Structural and functional alterations of the intramyocardial coronary arterioles in patients with arterial hypertension

BACKGROUND: In hypertensive patients with angina pectoris, the coronary vasodilator reserve is frequently impaired despite a normal coronary angiogram. Experimental data indicate that structural alterations of the intramyocardial coronary vasculature contribute to an increased minimal coronary resistance and a diminished coronary flow reserve. METHODS AND RESULTS: In 14 patients (10 men and 4 women) with arterial hypertension and 8 normotensive subjects, minimal coronary resistance and vasodilator reserve (dipyridamole: 0.5 mg/kg body wt, gas chromatographic argon method) were determined after the angiographic exclusion of relevant coronary artery disease. Coronary reserve was depressed in hypertensive patients (2.7 +/- 2.3 vs 4.6 +/- 1.3, P < or = .05) due to increased minimal coronary resistance (0.64 +/- 30 vs 0.24 +/- 0.055 mm Hg.min.100 g.mL-1, p < or = 0.002). In right septal biopsies, mean external arteriolar diameter (21.6 +/- 2.3 vs 17.2 +/- 2.5 microns, P < or = .001), mean arteriolar wall area (271 +/- 61 vs 172 +/- 62 microns 2, P < or = .01), percent medial wall area (69.9 +/- 4.0 vs 66.0 +/- 3.2%W, P < or = .05), mean periarteriolar fibrosis area (216 +/- 122 vs 104 +/- 68 microns 2, P < or = .05), and volume density of total interstitial fibrosis (3.6 +/- 1.8 vs 1.9 +/- 0.5Vv% fibrosis, P < or = .05) were increased in hypertensive patients compared with normotensive subjects. Minimal coronary resistance correlated with %W (r = .6, P < or = .003) and Vv% fibrosis (r = .62, P < or = .002). Left ventricular mass index (111 +/- 21 vs 97 +/- 17 g/m2, P = NS) and left ventricular end-diastolic pressure (12 +/- 6 vs 8 +/- 3 mm Hg, P = NS) did not correlate significantly with minimal coronary resistance. In multivariate analysis, both %W and Vv% fibrosis explained half of the variability of minimal coronary resistance (r2 = .5, P < or = .002). CONCLUSIONS: Structural remodeling of the intramyocardial coronary arterioles and the accumulation of fibrillar collagen are decisive factors for a reduced coronary dilatory capacity in patients with arterial hypertension and angina pectoris in the absence of relevant coronary artery stenoses.     

Health economic benefits and quality of life during improved glycemic control in patients with type 2 diabetes mellitus: a randomized, controlled, double-blind trial

CONTEXT: Although the long-term health benefits of good glycemic control in patients with diabetes are well documented, shorter-term quality of life (QOL) and economic savings generally have been reported to be minimal or absent. OBJECTIVE: To examine short-term outcomes of glycemic control in type 2 diabetes mellitus (DM). DESIGN: Double-blind, randomized, placebo-controlled, parallel trial. SETTING: Sixty-two sites in the United States. PARTICIPANTS: A total of 569 male and female volunteers with type 2 DM. INTERVENTION: After a 3-week, single-blind placebo-washout period, participants were randomized to diet and titration with either 5 to 20 mg of glipizide gastrointestinal therapeutic system (GITS) (n = 377) or placebo (n = 192) for 12 weeks. MAIN OUTCOME MEASURES: Change from baseline in glucose and hemoglobin A1c (HbA1c) levels and symptom distress, QOL, and health economic indicators by questionnaires and diaries. RESULTS: After 12 weeks, mean (+/-SE) HbA1c and fasting blood glucose levels decreased with active therapy (glipizide GITS) vs placebo (7.5% 0.1% vs 9.3%+/-0.1% and 7.0+/-0.1 mmol/L [126+/-2 mg/dL] vs 9.3+/-0.2 mmol/L [168+/-4 mg/ dL], respectively; P<.001). Quality-of-life treatment differences (SD units) for symptom distress (+0.59; P<.001), general perceived health (+0.36; P= .004), cognitive functioning (+0.34; P=.005), and the overall visual analog scale (VAS) (+0.24; P=.04) were significantly more favorable for active therapy. Subscales of acuity (+0.38; P=.002), VAS emotional health (+0.35; P=.003), general health (+0.27; P=.01), sleep (+0.26; P=.04), depression (+0.25; P=.05), disorientation and detachment (+0.23; P= .05), and vitality (+0.22; P=.04) were most affected. Favorable health economic outcomes for glipizide GITS included higher retained employment (97% vs 85%; P<.001), greater productive capacity (99% vs 87%; P<.001), less absenteeism (losses = $24 vs $115 per worker per month; P<.001), fewer bed-days (losses = $1539 vs $1843 per 1000 person-days; P=.05), and fewer restricted-activity days (losses = $2660 vs $4275 per 1000 person-days; P=.01). CONCLUSIONS: Improved glycemic control of type 2 DM is associated with substantial short-term symptomatic, QOL, and health economic benefits.     

Effect of feeding raw and treated common vetch seed (Vicia sativa) on the performance and egg quality parameters of laying hens

Two experiments were conducted to study the effect of feeding raw or treated common vetch seeds (V) on BW, feed intake (FI), egg production (EP), feed conversion (FC), egg weight (EW), shell thickness (ST), yolk color score (YC), and Haugh unit score (HU) of Single Comb White Leghorn hens for 56 d. In Experiment 1, diets contained 0, 7.5, 15, and 22.5% raw V. Compared with the control, the 22.5% V diet decreased (P < .05) BW, FI, and EP. In Experiment 2, intact or ground (G) V were either soaked (S) in water (1:5) for 24 h or autoclaved (A) at 103.5 x 10(3) Pa for 8 h, and then dried (D) at 55 C for 24 h. Eight diets were used, a corn soybean (control) and seven others, each containing 25% V, previously subjected to the forementioned treatments as follows: untreated V (UV), SDV, GSDV, ADV, GADV, SADV, and GSADV. Compared with the control, the UV diet decreased (P < .05) FI (75 vs 98 g) and EP (47.3 vs 88.7%), increased FC (1.99 vs 1.4 kg feed per dozen eggs), and induced BW loss (-63 vs 49 g). Soaking intact V improved (P < .05) FI (85 g) and EP (69%). Remaining treatments resulted in further improvement. Hens fed all V diets produced eggs with HU score 13 points better than that of the control (P < .05). In both experiments, EW, YC, and ST were not different among treatments. Results indicated that autoclaved V at 25% level was not detrimental to layers' performance.     

Efficacy of brompheniramine maleate for the treatment of rhinovirus colds

We tested the efficacy of brompheniramine maleate in a large randomized, controlled trial of volunteers with experimental rhinovirus colds. Brompheniramine (12 mg) or placebo was administered at 8:00 A.M. and 8:00 P.M. for < or = 4 days after the onset of symptoms (24, 36, or 48 hours after virus challenge). During the first 3 days of treatment (the first 4 days after virus challenge), nasal secretion weights were lower for infected evaluable subjects receiving brompheniramine (n = 113) than for controls (day 1: 4.3 g vs. 6.8 g; day 2: 4.8 g vs. 7.7 g; and day 3: 3.3 g vs. 5.3 g) (P < or = .03), as were rhinorrhea scores (day 1: 0.6 vs. 0.8; day 2: 0.5 vs. 0.8; and day 3: 0.3 vs. 0.5) (P < .03), sneeze counts (day 1: 1.8 vs. 3.6; day 2: 2.1 vs. 5.1; and day 3: 1.3 vs. 3.3) (P < or = .001), and sneeze severity scores (day 1: 0.3 vs. 0.6; day 2: 0.25 vs. 0.7; and day 3: 0.2 vs. 0.4) (P < .001) (n = 112). Cough counts were lower after day 1 of treatment for the brompheniramine group than for controls (4.7 vs. 7.9) (P = .05) (day 2 after virus challenge), and other symptoms were modestly reduced or were unaffected in the brompheniramine group. Total symptom scores were also lower for the brompheniramine group than for controls on treatment days 1 (4.8 vs. 6.0) (P = .03) and 2 (4.1 vs. 5.6) (days 2 and 3 after virus challenge) (P = .003). Treatment with brompheniramine was associated with the adverse effects of somnolence (n = 3) and confusion (n = 1). Brompheniramine was efficacious treatment for the sneezing, rhinorrhea, and cough associated with rhinovirus colds.     

Glucose utilization during interictal intervals in an epilepsy model induced by pilocarpine: a qualitative study

OBJECTIVE: To compare the antibiotic susceptibility of bacterial isolates from patients in the surgical intensive care unit (SICU) with hospital-wide bacterial susceptibility. DESIGN: Retrospective cohort analytic study. SETTING: Eight-bed SICU in a university-affiliated teaching hospital. PATIENTS: All hospitalized patients with culture results positive for microorganisms. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Antibiotic susceptibility data were collected retrospectively for all bacterial isolates from SICU patients during July 1, 1994, to June 30, 1995. All duplicate and surveillance cultures were eliminated from the data set. Susceptibility testing was conducted using our standard laboratory methods. Results were compared with the hospital-wide antibiogram (HWA) for the same time period. Comparisons were made using the chi(2) test with Yates correction or the Fisher exact test, as appropriate. Staphylococcus aureus (HWA, n=494; SICU, n=71) was significantly less susceptible to oxacillin (51% vs 28%; P<.001), ciprofloxacin (50% vs 25%; P<.001), erythromycin (46% vs 23%; P<.001), and clindamycin (51% vs 27%; P<.001) in the SICU. Coagulase-negative staphylococci (HWA, n=339; SICU, n=37) were significantly less susceptible to oxacillin (33% vs 16%; P=.04) and clindamycin (57% vs 34%; P=.02). Pseudomonas aeruginosa (HWA, n=513; SICU, n=96) was less susceptible to imipenem (85% vs 74%, P=.01) and more susceptible to ticarcillin-clavulanic acid (88% vs 100%, P<.001) in the SICU. Escherichia coli (HWA, n=474; SICU, n=36) was more susceptible to most penicillin-derivative antibiotics in the SICU (ampicillin [68% vs 83%, P=.06], ticarcillin [65% vs 86%, P=.01], mezlocillin [76% vs 95%, P=.01], and ticarcillin-clavulanic acid [88% vs 100%, P=.02]). CONCLUSIONS: The 2 most commonly isolated bacterial pathogens in the SICU (S aureus and P aeruginosa) had significantly different susceptibility patterns compared with the HWA. Surprisingly, E coli isolated in the SICU tended to be more susceptible to penicillin-derivative antibiotics. These data indicate that empiric antibiotic choices in the SICU may be better guided by unit-specific antibiograms.     

Effect of UVB 311 nm irradiation on normal human skin

OBJECTIVE: To determine the relative efficacy and morbidity of Ho:YAG versus Nd:YAG laser treatment of bullous lung disease in an animal model. SUMMARY BACKGROUND DATA: Laser coagulation procedures for treatment of emphysematous pulmonary bullae and heterogeneous emphysema continue to evolve. The role of lasers in lung volume reduction surgery remains controversial due to issues of relative efficacy and morbidity. The Nd:YAG laser is most commonly used for these procedures. We hypothesized that the shallower penetration of the Ho:YAG laser may be better suited for laser bullae coagulation and emphysema lung volume reduction with increased efficacy and reduced lung injury. METHODS: Thirty New Zealand White rabbits (15 normal rabbits; 15 with bullous lung disease) were evaluated with Ho:YAG compared to Nd:YAG laser exposures. Bullae were coagulated by either Ho:YAG or Nd:YAG treatment. In all animals (bullous-induced and normals), unaffected lung tissue in the upper lobes and contralateral lungs were treated with 5 spot exposures of Nd:YAG and Ho:YAG, each to assess depth of lung injury. Animals were sacrificed at Days 0, 7, and 21 and their lungs were examined histologically. RESULTS: Ho:YAG and Nd:YAG exposures caused equivalent lung injury to normal lung tissue. In the acute phase, parenchymal necrosis depth was similar for both Ho:YAG and Nd:YAG (850 +/- 273 microns vs. 900 +/- 270 microns respectively, p = 0.7). By Day 7, lung necrosis depth was 925 +/- 133 microns Ho:YAG vs. 1225 +/- 235 microns Nd:YAG (p = 0.33), and lung fibrosis depth was 300 +/- 134 microns Ho:YAG vs. 558 +/- 127 microns Nd:YAG (p = 0.11). By Day 21, pulmonary parenchymal necrosis was not seen. Pleural fibrosis depth was maximal at Day 21, reaching 250 +/- 102 microns for Ho:YAG vs. 300 +/- 156 microns Nd:YAG (P = 0.88). Pleural necrosis depth was 67 +/- 42 microns Ho:YAG vs 48 +/- 34 microns Nd:YAG (p = 0.42) on Day 7 and resolved by Day 21. During surgical coagulation procedures, the Ho:YAG laser was dramatically more efficient in coagulating bullae. The Ho:YAG laser required less exposure at equivalent power and resulted in immediate desiccation of bullae, in sharp contrast to the Nd:YAG laser. CONCLUSIONS: Because the Ho:YAG was more effective and did not result in more acute lung injury than the standard Nd:YAG laser in this study, Ho:YAG lasers may have improved potential for laser treatment of bullae or lung volume reduction surgery (LVRS) compared to Nd:YAG lasers.     

Biochemical-morphological modifications of platelet membranes during pregnancy-induced hypertension

Progesterone profiles were monitored in goats housed in single (n = 9) or group (n = 14) pens during winter (JJA) and spring (SON). Normal cycles (n = 97) were < or = 30 days. Extended cycles (n = 45) were > 30 days and, except for one cycle with a persistent corpus luteum, had periovulatory periods of 10 to 20 days (n = 29) or averaging 65.1 days in length (n = 15), mostly characterised by recurrent oestrus and/or occasional transient rises in progesterone. The proportion of normal cycles occurring in winter was 87.5% (28/32) and 77.7% (42/54) for goats in single and group pens respectively, falling to 62.5% (15/24) and 37.5% (12/32) respectively in spring. The distribution of normal vs extended cycles according to season was significant (P < 0.05, single; P < 0.001 group pens). Goats housed communally experienced a greater fall in the percentage of normal cycles in spring, possibly due to increased stress associated with group feeding. Within each season, however, housing per se did not influence the distribution of normal vs extended cycles. For normal cycles, Harvey's Analysis of Variance showed that season was significantly associated with length of the periovulatory period (3.99 days (JJA) vs 5.79 days (SON); P < 0.001), oestrus detection rate (87% (JJA) vs 55% (SON); P < 0.01) and oestrus duration (1.94 days (JJA) vs 1.13 days (SON); P < 0.05). In contrast, luteal phase length was not affected by season, but was significantly associated with housing (16.93 days (single pens) vs 18.32 days (group pens); P < 0.01). The reduction in ovarian activity observed in spring may reflect a seasonal reduction in fertility, possibly linked with increasing temperature and photoperiod.     

Cryopreserved arterial allografts in the treatment of major vascular infection: a comparison with conventional surgical techniques

OBJECTIVE: Recent findings with cryopreserved heart valve allografts in the treatment of infectious endocarditis suggest that the use of cryopreserved arterial allografts may improve the outcome in patients with vascular infections. METHODS: Seventy-two patients with mycotic aneurysms (n = 29) or infected vascular prostheses (n = 43) of the thoracic (n = 26) or abdominal aorta (n = 46) were treated with in situ repair and extra-anatomic reconstruction using prosthetic material (n = 38) or implantation of a cryopreserved arterial allograft (n = 34). Disease-related survival and survival free of reoperation were assessed. Morbidity, cumulative lengths of intensive care, hospitalization, antibiotic treatment, and costs were calculated per year of follow-up. RESULTS: The use of cryopreserved arterial allografts was superior to conventional surgery in terms of disease-related survival (P =.008), disease-related survival free of reoperation (P =.0001), duration of intensive care per year of follow-up (median 1 vs 11 days; range 1 to 42 vs 2 to 120 days; P =.001), hospitalization (14 vs 30 days; range 7 to 150 vs 15 to 240 days; P =.002), duration of postoperative antibiotic therapy (21 vs 40 days; range 21 to 90 vs 60 to 365 days; P =.002), incidence of complications (24% vs 63%; P =.005), and elimination of infection (91% vs 53%; P =.001). In addition, costs were 40% lower in the group treated by allografts (P =.005). CONCLUSIONS: The use of cryopreserved arterial allografts is a more effective treatment for mycotic aneurysms and infected vascular prostheses than conventional surgical techniques.     

Hormonal modulation of the physiologic responses of calves infected with Eimeria bovis

OBJECTIVE: To determine whether an estradiol-progesterone (EP) growth implant would have an effect on febrile responses and on the catabolic component of Eimeria bovis infection. ANIMALS: 27 Holstein bull calves. PROCEDURE: Calves were assigned to treatment groups as: control (n = 5), EP implant (EP, n = 5), E bovis-inoculated (coccidia: C, n = 7), pair fed (n = 4), or EP plus E bovis-inoculated coccidia (EP/C, n = 6) groups. Calves were provided subcutaneous EP implants at 8 weeks of age, and were inoculated with 2 x 10(5) oocysts of E bovis at 11 weeks of age. Body weight was measured on postinoculation day (PID) 0, 14, and 28. Rectal temperature and food intake were determined and fecal samples were collected daily from PID 15 to 28. Blood samples were collected on PID 24 for analysis of CD2+, CD4+, and CD8+ antigens and plasma insulin-like growth factor I concentration. Blood samples were collected at 15-minute intervals for measurement of pulsatile growth hormone release. RESULTS: Group-EP/C calves had fever for 2 days versus 5 days for group-C calves (P < 0.05). These calves had diarrhea for fewer days than did their group-C counterparts (P < 0.05). Fibrinogen and glucose values were high in group-C (P < 0.05) but not group-EP/C calves. The latter had positive weight gain from PID 14 to 28, whereas group-C calves had weight loss (P < 0.05). Plasma insulin-like growth factor I concentration was reduced by infection (P < 0.05). EP-treated noninfected calves had increased numbers of CD2+, CD4+, and CD8+ blood mononuclear cells (P < 0.05). CONCLUSIONS: EP has a protective effect in calves infected with E bovis. This may relate to changes in immune function induced by EP. CLINICAL RELEVANCE: Treatment of calves with EP could offer some protection against the often severe wasting and debilitation associated with E bovis infection.     

Hypokalemia and potassium excretion in stroke patients

OBJECTIVES: To determine (1) the prevalence of hypokalemia (plasma potassium < or = 3.4 mmol/L) in a group of stroke patients in comparison with age- and sex-matched groups of patients having sustained a myocardial infarction or having mild hypertension and (2) the association between plasma potassium concentration and stroke outcome. DESIGN: Observational study. PARTICIPANTS: A total of 421 consecutive stroke patients admitted to a teaching hospital, 150 consecutive patients 50 years or older with myocardial infarction admitted to the hospitals Coronary Care Unit, and 161 out-patients 60 years or older with borderline and established hypertension. MEASUREMENTS: All stroke and cardiac patients had plasma urea and electrolytes estimated within 2 hours of hospital admission; in the hypertensive group blood samples were taken in clinic. Stroke patients had blood pressure, stroke severity (Barthel score) and smoking status recorded. A sub-group of 61 stroke patients and all 79 hypertensive patients not taking antihypertensive medication had 24-hour urine electrolyte excretion measured. Outcome (independent, dependent, or dead) at 3 months post-stroke was established in 349 patients. RESULTS: Hypokalemia occurred more frequently in stroke patients than in patients with myocardial infarction (84 (20%) vs 15 (10%), P = .008) or patients with hypertension (84 (20%) vs 13 (8%), P < .001), even when patients taking diuretics were excluded from analysis (56 (19%) vs 12 (9%) of cardiac group, P = .014 and 56 (19%) vs 4 (5%) of hypertensive group, P = .005, respectively). 24-hour urine excretion of potassium and the potassium:creatinine ratio was lower in stroke patients than in hypertensive patients (41 +/- 21 vs 62 +/- 25 mmol/24 hour, P = .001, 5.5 +/- 2.2 vs 7.4 +/- 2.6 mmol/24 hour, P = .001, respectively). On survival analysis, a lower plasma potassium on admission to hospital was associated with an increased chance of death, independent of age, stroke severity, history of hypertension, blood pressure level, or smoking history (hazard ratio 1.73 (95% CI: 1.03-2.9) for a 1 mmol/L lower plasma potassium concentration). CONCLUSIONS: Hypokalemia post stroke is common and may be associated with a poor outcome.     

Single serum progesterone as a screen for ectopic pregnancy: exchanging specificity and sensitivity to obtain optimal test performance

OBJECTIVE: To investigate the diagnostic accuracy of screening serum P in diagnosis of ectopic pregnancy (EP) and to identify a cutoff value that provides the best compromise between test sensitivity and specificity. DESIGN: Retrospective analysis. SETTING: University hospital. INTERVENTIONS: Observation only. PATIENTS: First trimester pregnant women at risk for EP. MAIN OUTCOME MEASURE: Single P measurements were obtained from 3,674 pregnancies with outcomes defined as EP, viable intrauterine pregnancy (IUP), and spontaneous abortion (SAB). Diagnostic accuracy of the test was analyzed by generating receiver operating characteristic (ROC) curves, which quantify the ability of the test to distinguish EP and SAB from IUP. RESULTS: Diagnostic accuracy for EP versus IUP was 88.7% +/- 0.1% (mean +/- SEM); for SAB versus IUP, 93.8% +/- 0.4%; and for SAB + EP versus IUP, 92.8% +/- 0.4%. Diagnostic accuracy for SAB versus EP was only 39.4% +/- 0.2%. In the interval of 15.0 to 19.9 ng/mL (47.7 to 63.3 nmol/L), P missed 5.3% of the EPs and incorrectly included 84.3% of the viable IUPs; in the interval of 20.0 to 24.9 ng/mL (63.6 to 79.2 nmol/L), sensitivity improved in that only 3.5% of the EPs were missed but 88.8% of viable IUPs were included incorrectly. A cutoff value of > or = 17.5 ng/mL (55.7 nmol/L), the median point of the 15.0 to 19.9 ng/mL (47.7 to 63.3 nmol/L) interval, missed only 35 of 423 (8.3%) total EPs in the study. CONCLUSION: Analysis of ROC curves demonstrates that single serum P has high diagnostic accuracy for differentiating accidents of pregnancy (SAB and EP) from viable IUP, both individually (SAB versus IUP and EP versus IUP) and collectively (SAB + EP versus IUP); it cannot efficiently discriminate SAB versus EP. We conclude that for P > or = 17.5 ng/mL (55.7 nmol/L), patients thought to be at risk for EP may be followed reasonably without ultrasound or further invasive diagnostic studies.     

Gender differences in strength and muscle fiber characteristics

Strength and muscle characteristics were examined in biceps brachii and vastus lateralis of eight men and eight women. Measurements included motor unit number, size and activation and voluntary strength of the elbow flexors and knee extensors. Fiber areas and type were determined from needle biopsies and muscle areas by computerized tomographical scanning. The women were approximately 52% and 66% as strong as the men in the upper and lower body respectively. The men were also stronger relative to lean body mass. A significant correlation was found between strength and muscle cross-sectional area (CSA; P < or = 0.05). The women had 45, 41, 30 and 25% smaller muscle CSAs for the biceps brachii, total elbow flexors, vastus lateralis and total knee extensors respectively. The men had significantly larger type I fiber areas (4597 vs 3483 microns2) and mean fiber areas (6632 vs 3963 microns2) than the women in biceps brachii and significantly larger type II fiber areas (7700 vs 4040 microns2) and mean fiber areas (7070 vs 4290 microns2) in vastus lateralis. No significant gender difference was found in the strength to CSA ratio for elbow flexion or knee extension, in biceps fiber number (180,620 in men vs 156,872 in women), muscle area to fiber area ratio in the vastus lateralis 451,468 vs 465,007) or any motor unit characteristics. Data suggest that the greater strength of the men was due primarily to larger fibers. The greater gender difference in upper body strength can probably be attributed to the fact that women tend to have a lower proportion of their lean tissue distributed in the upper body.(ABSTRACT TRUNCATED AT 250 WORDS)     

Composition analysis of pork carcasses by dual-energy x-ray absorptiometry

Dual-energy x-ray absorptiometry (DXA) was used as a noninvasive method to measure the composition of pig carcasses. A total of 181 half-carcasses (10 to 51 kg, from pigs slaughtered at approximately 30, 60, 90, and 120 kg) were scanned using a Lunar (Madison, WI) DPX-L densitometer. The DXA measurements of fat, lean, bone mineral, and total tissue mass were compared with chemical analysis for fat, water, protein, total ash, and scale weight. The mean value for total tissue mass by DXA was slightly less than the mean carcass weight (32.3 kg vs 33.6 kg, P > .05, R2 = .998). Although highly correlated (R2 = .81), the DXA measurement of the percentage of fat in the half-carcass was less (P < .001) than the chemical measurement (19.5 vs 24.9%). The DXA measurement of lean tissue mass (total mass less fat and bone mineral) was correlated with carcass protein (R2 = .97) and water (R2 = .99) content. The correlation (R2) between DXA bone mineral content and carcass ash content was only .68; however, DXA bone mineral content was more highly correlated with carcass weight (R2 = .93) than was carcass ash content (R2 = .70). When we used the DXA R value (ratio of the attenuation coefficients for fat and lean) to predict percentage of fat in the carcass, the mean value for predicted carcass fat was 25.9% (P > .05). Similarly, carcass protein and water content were predicted from DXA lean. Using DXA region of interest analysis, estimates of the fat content of the shoulder and ham regions were close to chemical values; however, DXA underestimated the fat content of the loin and side regions by 20 and 28%, respectively. When prediction equations were used to evaluate DXA measurements of the half-carcasses of 28 gilts and 37 boars slaughtered at approximately 120 kg, the half-carcasses of gilts contained more fat (33.9 vs 27.8%, P < .001), less protein (14.1 vs 16.1%, P < .001), and less water (45.9 vs 52.1%, P < .001) than those of boars. These results indicate that DXA could be a valuable research tool for measuring the composition of pig carcasses. On the basis of the results of this study, prediction equations were revised for the DXA estimation of fat, protein, and water content of the half-carcass: Fat (%) = 450 - (315 x DXA R value), Protein (g) = -145 + (.23 x DXA lean), and Water (g) = 150 + (.73 x DXA lean). Furthermore, it seems that separate prediction equations are needed for regional analysis.     

Neuroradiology case of the day. Burkitt lymphoma

We describe the clinical and laboratory manifestations of human granulocytic ehrlichiosis (HGE) in eight patients for whom cultures were positive for the HGE agent and compare them with 15 patients for whom cultures were negative but who fulfilled a modified New York State Surveillance definition for HGE. Polymerase chain reaction analysis was positive in 8 (100%) of 8 culture-positive cases vs. 3 (20%) of 15 culture-negative cases (P < .001), morulae were detected in 7 (100%) of 7 culture-positive cases in which tests were performed vs. 0 of 15 culture-negative cases (P < .001), and a fourfold change in antibody titer was demonstrated in 6 (75%) of 8 culture-positive cases vs. 9 (69%) of 13 culture-negative cases (P = not significant). Patients for whom cultures were positive had higher mean oral temperatures +/- SD at presentation than did patients for whom cultures were negative (38.6 degrees C +/- 0.7 degree C vs. 37.2 degrees C +/- 0.8 degree C, respectively; P = .002). Other symptoms and signs were not significantly different between the two groups. Multivariate analysis revealed that the lymphocyte count at presentation was significantly lower in culture-positive cases than in culture-negative cases. Clinical response to treatment was similar in the two groups. Culture confirmation of HGE is the gold standard for defining the sensitivity and specificity of other diagnostic tests presently being developed.     

Prehospital-initiated vs hospital-initiated thrombolytic therapy. The Myocardial Infarction Triage and Intervention Trial

OBJECTIVE: To determine the effect of prehospital-initiated vs hospital-initiated treatment of myocardial infarction on clinical outcome. DESIGN: Randomized, controlled clinical trial. SETTING: Multicenter study involving 19 hospitals and all paramedic systems in the Seattle, Wash, metropolitan area. PATIENTS: A total of 360 patients with symptoms for 6 hours or less, no risk factors for serious bleeding, and ST-segment elevation were selected by paramedics and a remote physician for inclusion into the trial. They represented 4% of patients with chest pain who were screened and 21% of those with acute infarction. INTERVENTIONS: Patients were allocated to have aspirin and alteplase treatment initiated before or after hospital arrival. Intravenous sodium heparin was administered to both groups in the hospital. MAIN OUTCOME MEASURE: The primary endpoint was a ranked composite score (combining death, stroke, serious bleeding, and infarct size). The relation between time to treatment and outcome (composite score, infarct size, ejection fraction, and mortality) was also assessed. RESULTS: Initiating treatment before hospital arrival decreased the interval from symptom onset to treatment from 110 to 77 minutes (P < .001). Although more patients whose therapy was initiated before hospital arrival had resolution of pain by admission (23% vs 7%; P < .001), there were no significant differences in the composite score (P = .64), mortality (5.7% vs 8.1%), ejection fraction (53% vs 54%), or infarct size (6.1% vs 6.5%). A secondary analysis of time to treatment and outcome showed that treatment initiated within 70 minutes of symptom onset was associated with better outcome (composite score, P = .009; mortality, 1.2% vs 8.7%, P = .04; infarct size, 4.9% vs 11.2%, P < .001; and ejection fraction, 53% vs 49%, P = .03) than later treatment. Identification of patients eligible for thrombolysis by paramedics reduced the hospital treatment time from 60 minutes (for patients not in the study) to 20 minutes (for study patients allocated to begin treatment in the hospital). CONCLUSION: There was no improvement in outcome associated with initiating treatment before hospital arrival; however, treatment within 70 minutes of symptom onset--whether in the hospital or in the field--minimized the infarct process and its complications.     

Rectal trauma: management based on anatomic distinctions

Principles of rectal wound management, including routine diversion, injury repair, presacral drainage and distal washout, evolved from World War II and the Vietnam conflict and have been questioned in recent years. We believe significant confusion arises because of imprecise definition of injury location relative to retroperitoneal involvement. Our 5-year experience with penetrating rectal injuries at a Level I trauma center was analyzed. Injuries to the anterior and lateral surfaces of the upper two-thirds of the rectum were classified as intraperitoneal (IP, serosalized), and those of the posterior surface extraperitoneal (EP, no serosa); injuries to the lower one-third were EP. A total of 58 injuries were managed (92% gunshot wounds). Of these, 16 were IP, and 42 had some EP component. Ten patients underwent repair without diversion (6 IP, 4 EP); there were no leaks. Ten septic complications occurred in the remaining population: 2 necrotizing fasciitis, 5 abdominal abscess, and 3 presacral infections (PIs) (2 presacral abscesses and 1 wound tract infection). PI is the only complication that can be specifically associated with EP rectal injuries relative to management; as associated injury confounds interpretation of the other complications. The operative management in the 38 patients with diverted EP wounds with respect to presacral infection (PI) demonstrated the following: repair injury (n = 10), 0 PI versus no repair (n = 28), 3 PI (P = 0.55); washout (n = 33), 2 PI versus no washout (n = 5), 1 PI (P = 0.35); presacral drain (n = 30), 1 PI versus no drain (n = 8), 2 PI (P = 0.11). We conclude that most IP injuries can be managed with primary repair. EP wounds to the upper two-thirds of the rectum should usually be repaired. EP wounds to the lower one-third, which are explored and repaired, do not require drainage. EP wounds that are not explored should be managed with presacral drainage to minimize the incidence of presacral abscess.     

A comparison of a fluoroscopy-free mechanical targeting system and a free-hand technic for the placement of distal interlocking screws of tibial nails

Recently, radiation-independent aiming devices for the tibia which compensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement with a radiation-independent distal aiming system and the free-hand technique. In an oblique cadaveric tibial fracture, a surgeon inexperienced with either technique performed a statically locked intramedullary nailing. For the aiming system and free-hand technique respectively, the total operation time was 25.4 +/- 11.3 vs 30.9 +/- 14.3 min (P = 0.029), the distal locking time was 16.7 +/- 8.6 vs 21.9 +/- 10.5 min (P = 0.004), the total fluoroscopy time was 9 +/- 5 vs 93 +/- 34 s (P < 0.0001), the distal locking fluoroscopy time was 0 versus 88 +/- 33 s (P < 0.0001), and the screw destruction was -0.7 +/- 5.2 vs 26.8 +/- 31.6 microns (P = 0.001). The failure rate was 1.6% (1 of 60 screws) in both groups. These results suggest that aiming devices can eliminate the need for radiation during distal interlocking screw placement.     

Disparate effects of insulin on isolated rabbit afferent and efferent arterioles

Despite evidence that insulin per se may be an important regulator of glomerular hemodynamics, little is known about its direct action on the glomerular afferent arterioles (Af-Art) and efferent arterioles (Ef-Art), the crucial vascular segments that control glomerular hemodynamics. In the present study, we examined the direct effect of physiological concentrations of insulin on isolated microperfused rabbit Af- and Ef-Arts. After cannulation, vessels were equilibrated in insulin-free medium for 30 min. To determine whether insulin causes vasodilation or constriction, increasing doses (5, 20, and 200 microU/ml) were added to the bath and lumen of arterioles that were either preconstricted to 50% of control diameter with norepinephrine or left nonpreconstricted. Insulin caused no vasoconstriction in either Af- or Ef-Arts, but it reversed norepinephrine-induced constriction in Ef-Arts but not Af-Arts (suggesting a vasodilator action selective to the Ef-Art): at 200 microU/ml, insulin increased Ef-Art luminal diameter by 75.8 +/- 7.0% from the preconstricted level (n = 6; P < 0.008). The vasorelaxant effect of insulin on Ef-Arts was not affected by blockade of either endothelium-derived relaxing factor/nitric oxide or prostaglandin synthesis. Despite the lack of effect of insulin on Af-Art when added after the equilibration period, when Af-Arts were equilibrated in the presence of either 20 or 200 microU/ml insulin, their basal diameter was significantly reduced (11.7 +/- 0.9 microns; P < 0.025, n = 6, and 12.0 +/- 0.9 microns; P < 0.025, n = 7, respectively) compared with nontreated Af-Arts (16.2 +/- 1.3 microns; n = 7). In conclusion, this study demonstrates that at physiological concentrations, insulin dilates NE-constricted Ef-Arts, while insulin pretreatment enhances Af-Art tone. The disparate actions of insulin on the Af- vs the Ef-Art may contribute to its beneficial effect on glomerular hypertension.     

Endotoxin temporarily impairs canine jejunal absorption of water, electrolytes, and glucose

OBJECTIVE: To evaluate the usefulness of a portable, computer-based, oscillometric, noninvasive blood pressure monitor for the automatic surveillance of postoperative infrainguinal bypasses. DESIGN: Prospective unblinded study. SETTING: Regional tertiary care Veterans Affairs medical center. PATIENTS: A total of 60 limbs were examined in 3 groups (n = 20 in each group): normal, asymptomatic volunteers; older patients with symptomatic peripheral vascular disease; and patients who had undergone infrainguinal bypass procedures. INTERVENTIONS: Noninvasive blood pressure monitor pressures, complete lower extremity arterial studies with Doppler ankle-brachial index (ABI), segmental pressures, and pulse volume recordings were performed in all groups. The patients who had undergone surgery also had hourly noninvasive blood pressure measurements taken. MAIN OUTCOME MEASURES: Ankle-brachial indices obtained with the noninvasive blood pressure monitor were compared with simultaneous manual Doppler ABIs and pulse volume recordings. RESULTS: There was a significant overall correlation between the Doppler-derived ABIs and automatic oscillometric values (r = 0.89, P < .001). Although there was a slight difference in absolute values (+/-SEM) (0.90 +/- 0.03 vs 0.84 +/- 0.03, respectively), an excellent correlation was found between the 2 methods in the clinically relevant range of ABI values between 0.60 and 1.10. The oscillometric method, however, overestimated the ABI when it was less than 0.60 by the Doppler method (0.61 +/- 0.02 vs 0.44 +/- 0.03, P < .001) and underestimated it when it was more than 1.10 (1.05 +/- 0.02 vs 1.16 +/- 0.01, P < .001). (All values given as +/-SEM.) Oscillometric overestimation correlated with depressed pulse volume recording waveforms (P < .001) or diminished pulse volume recording amplitudes of less than 10 mm (P < .001). CONCLUSION: The automatic oscillometric monitor provides a useful, accurate, objective, and quantitative method for postoperative bypass graft surveillance.