Coronary vasodilatory capacity is impaired in patients with dilated cardiomyopathy

Increases in wall stress because of left ventricular enlargement and/or alterations in coronary vasomotor tone might affect myocardial blood flow and vasodilatory capacity in patients with dilated cardiomyopathy. To test this hypothesis myocardial blood flow was measured at rest and during intravenous administration of dipyridamole (0.56 mg/kg) using dynamic nitrogen 13-ammonia positron emission tomography (two-compartment model) in 10 patients with dilated cardiomyopathy (mean left ventricular ejection fraction 28 +/- 8% 1 woman, 9 men; 47 +/- 13 years of age). Ten age and gender matched healthy volunteers served as controls. Coronary artery disease was ruled out by coronary angiography and left ventricular hypertrophy by two dimensional-echocardiography. Baseline heart rate (70 +/- 13 v 64 +/- 12 bpm), systolic blood pressure (111 +/- 20 v 114 +/- 12 mm Hg) and rate pressure product (7,686 +/- 1264 v 7,306 +/- 1,645) were similar in patients and controls. During dipyridamole administration, the rate pressure product increased similarly in both groups. Myocardial blood flow at rest did not differ between groups of patients and volunteers (0.69 +/ -0.27 v 0.67 +/- 0.17 mL/g/min) but correlated with the rate pressure product only in controls (myocardial blood flow, 0.18 + 0.000068214; rate pressure product, .67; P < .05). Hyperemic myocardial blood flow was lower in patients (1.57 +/- 0.39 v 1.92 +/- 0.31 mL/g/min, p < .05, whereas myocardial flow reserve did not differ between groups of patients and controls (2.57 +/- 1.15 v 3.02 +/- 0.94). Coronary vasodilatory capacity is reduced in patients with severe nonischemic cardiomyopathy. Increases in extravascular compressive forces or increased serum catecholamine levels, which in turn induce coronary vasoconstriction, might account for this finding.     

The design of today's operating rooms

With the exception of radiation therapy, the surgical suite is still the most costly area in a health care facility to renovate or construct. It is also the most needs intensive, as far as staff, equipment, material, and building system. Health care providers need an environmentally sensitive area that meets the needs of today, as well as the future. It is equally important to create a working environment that promotes staff comfort, while streamlining time and cost.     

Effect of N-methyl-D-aspartate receptor blockade on the control of cerebral O2 supply/consumption balance during hypoxia in newborn pigs

Using dizocilpine (MK-801), we tested the hypothesis that N-methyl-D-aspartate (NMDA) receptors are important controllers of cerebral O2 supply/consumption balance in newborn piglets both during normoxia and hypoxia. Twenty-five 2 to 7-day-old piglets were anesthetized and divided into four groups: (1) Normoxia (n = 6), (2) Normoxia + MK-801 (n = 6), (3) Hypoxia (n = 6), and (4) Hypoxia + MK-801 (n = 7). Regional cerebral blood flow (rCBF) in ml/min/100 g was measured using 14C-iodoantipyrine, and we determined arterial and venous O2 saturations by microspectrophotometry, calculating cerebral O2 consumption (VO2) in ml O2/min/100 g in the cortex, hypothalamus and pons. MK-801 did not significantly affect regional VO2 or rCBF in normoxic piglets. Hypoxia resulted in an increase in local rCBF compared to controls: from 41 +/- 6 to 103 +/- 18 in the cortex; 34 +/- 7 to 101 +/- 20 in the hypothalamus; and 45 +/- 10 to 95 +/- 11 in the pons. Pretreatment with MK-801 abolished this hypoxic flow effect in the cortex (51 +/- 2) and hypothalamus (49 +/- 5), but not in the pons (91 +/- 17). Similar results were observed for VO2 with control values of 1.9 +/- 0.3, 1.6 +/- 0.2 and 2.1 +/- 0.3 for the cortex, hypothalamus and pons respectively. Hypoxia resulted in an increase in the VO2 to 3.9 +/- 0.4 (cortex), 3.8 +/- 0.6 (hypothalamus) and 3.9 +/- 0.8 (pons). Pretreatment with MK-801 prior to hypoxia abolished these effects in the cortex (2.1 +/- 0.2) and hypothalamus (2.1 +/- 0.2), but not in the pons (2.9 +/- 0.2). These findings suggest that NMDA receptors may play a role in the control of cerebral metabolism during hypoxia in this immature porcine model.     

Relation between negligent adverse events and the outcomes of medical-malpractice litigation

BACKGROUND: We have previously shown that in New York State the initiation of malpractice suits correlates poorly with the actual occurrence of adverse events (injuries resulting from medical treatment) and negligence. There is little information on the outcome of such lawsuits, however. To assess the ability of malpractice litigation to make accurate determinations, we studied 51 malpractice suits to identify factors that predict payment to plaintiffs. METHODS: Among malpractice claims that we reviewed independently in an earlier study, we identified 51 litigated claims and followed them over a 10-year period to determine whether the malpractice insurer had closed the case. We obtained detailed summaries of the cases from the insurers and reviewed the litigation files if the outcome of a case differed from the outcome predicted in our original review. RESULTS: Of the 51 malpractice cases, 46 had been closed as of December 31, 1995. Among these cases, 10 of 24 that we originally identified as involving no adverse event were settled for the plaintiffs (mean payment, $28,760), as were 6 of 13 cases classified as involving adverse events but no negligence (mean payment, $98,192) and 5 of 9 cases in which adverse events due to negligence were found in our assessment (mean payment, $66,944). Seven of eight claims involving permanent disability were settled for the plaintiffs (mean payment, $201,250). In a multivariate analysis, disability (permanent vs. temporary or none) was the only significant predictor of payment (P=0.03). There was no association between the occurrence of an adverse event due to negligence (P = 0.32) or an adverse event of any type (P=0.79) and payment. CONCLUSIONS: Among the malpractice claims we studied, the severity of the patient's disability, not the occurrence of an adverse event or an adverse event due to negligence, was predictive of payment to the plaintiff.     

T20 measurements for 1H(d

When cytochrome b5 is added to large unilamellar vesicles (LUVs) of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC), it binds predominantly in a 'loose,' or transferable form. Prolonged incubation of 30 degrees C leads to insertion in the physiological 'tight,' nontransferable form, with a halftime for the loose --> tight conversion of approx. 9 days. In this study, the effect of cholesterol on the rate of tight insertion was determined. Tight binding was assayed by depleting the LUVs of loose cytochrome b5 with an excess of SUV acceptors and then separating the liposome populations by gel-filtration or velocity sedimentation. Incorporation of cholesterol into the LUVs was found to markedly increase the rate of tight insertion, even though cholesterol decreases the equilibrium binding constant and saturation level of protein binding. The effect is not a continuously increasing function of cholesterol content, but attains a maximum at 20-25% mol%, where the rate enhancement is approx. 10-fold over baseline. At higher cholesterol levels, the rate decreases, returning to baseline at 40 mol% cholesterol. These observations are highly unusual in that cholesterol generally decreases the membrane binding affinity and the permeability of solutes, and does so as a monotonic function of cholesterol concentration (above the liquid-crystalline phase transition of the phospholipids). It is suggested that tight insertion is enhanced by lipid-protein packing mismatches and by bilayer fluidity; the former increases monotonically with increasing cholesterol whereas the latter decreases monotonically. At 20-25 mol% cholesterol the optimum balance of these physical properties is obtained for tight insertion.     

Effect of missed hemodialysis treatments on mortality in patients with end-stage renal disease

Dietary fibre is believed to protect against a range of Western diseases, including colorectal cancer. Whole plant cell walls make up most of the dietary fibre in Western diets, but their role in disease protection has rarely been studied. At least in vitro, suberized plant cell walls possess novel properties that suggest they could have exceptional potential for cancer protection. Our aim was to test in a rat model the abilities of suberized cell walls from potato skins and commercial cork to decrease gastrointestinal transit time and to protect against the development of aberrant crypts, an early marker of colon cancer. Groups of six rats were fed a modified AIN-76 diet as the control diet and this diet supplemented with 5% dietary fibre from the following sources: commercial cork, commercial-cork cell walls and potato-skin cell walls. A diet supplemented with wheat bran was used as a positive control. The colon carcinogen IQ (2-amino-3-methylimidazo[4,5-f]quinoline) was administered for 3 weeks and after another 12 weeks the number of aberrant crypts determined. Transit times were determined after feeding the diets for 4 weeks. Compared with rats fed the control diet, rats fed diets supplemented with the suberized cell-wall preparations had decreased transit times and had significantly fewer aberrant crypts, with no aberrant crypt foci containing four or more crypts. The diets supplemented with suberized cell walls were more effective than thediet supplemented with wheat bran. We conclude that suberized and lignified cell walls, but particularly suberized, may play an important role in protection against Western diseases, including colorectal cancer. Failure to distinguish suberized and lignified plant cell walls from other sources of non-starch polysaccharides may provide a major limitation in current assessments of the role of dietary fibre in preventing colorectal cancer in humans.     

The Fc gammaRIIIA-158F allele is a risk factor for systemic lupus erythematosus

OBJECTIVE: To study whether the Fc gammaRIIIA-158V/F polymorphism, which affects IgG binding affinity, is a risk factor for systemic lupus erythematosus (SLE). METHODS: We genotyped a group of 70 Caucasian SLE patients for all known Fc gammaR polymorphisms. Of this group, 45 patients (64%) had nephritis. In 35 patients, this diagnosis was confirmed by renal biopsy. RESULTS: In the total group of 70 SLE patients, the frequency of the Fc gammaRIIIA-158F allele was 0.74, versus 0.57 in healthy controls (P = 0.003). The genotype distribution of the Fc gammaRIIIA-158V/F polymorphism was also significantly different from that of the control population (P = 0.004). The distribution of the other Fc gammaR polymorphisms--Fc gammaRIIA-131R/H, Fc gammaRIIIB-NA(1,2), and Fc gammaRIIIA-48L/R/H--was similar in SLE patients and controls. CONCLUSION: In our group of SLE patients, only the distribution of the alleles of the Fc gammaRIIIA-158V/F polymorphism was significantly different from that in the control group. This might indicate that macrophage expression of the Fc gammaRIIIA-158F isoform is involved in the disturbed clearance of immune complexes in patients with SLE.     

Clinical picture and differential diagnosis of cardiomyopathy and myocarditis

BACKGROUND: The purpose of this prospectively randomized study was to evaluate intraoperative as well as long-term performance of different coating materials for knitted Dacron aortobifemoral prostheses. PATIENTS AND METHODS: Between 1989 and 1992 a total of 150 consecutive patients who underwent aortobifemoral bypass were randomized for three different coating materials: gelatine (Unigraft; n = 49), collagen (Hemashield; n = 50) and human albumin (USCI; n = 51). Intra- and perioperative data such as duration of operation, clamping time, blood loss, and early complications were obtained as well as yearly follow-up examinations up to five years. Frequency of late complications, graft patency, and patient survival were observed. RESULTS: No statistically significant difference of intraoperative data could be obtained. In every group 6% of patients presented with anastomotic aneurysm in the groin. Primary patency rates were Unigraft 92%, Hemashield 91%, USCI 92% (no significant difference, n.s.), secondary patency rates after 5 years were Unigraft 98%, Hemashield 95%, USCI 94% (n.s.). CONCLUSIONS: Overall superiority of one particular type of prosthesis could not be stated. In order to prevent sudden graft failure associated with progressive arteriosclerotic disease or from late anastomotic aneurysm regular follow-up examinations should follow aorto-bifemoral bypass.