Renovascular interaction of epinephrine, dopamine, and intraperitoneal sepsis

OBJECTIVE: To determine the effect of intraperitoneal sepsis on the systemic and renal actions of the continous infusion of epinephrine or dopamine, and during the concurrent administration of both drugs. DESIGN: Prospective, randomized study. SETTING: Laboratory at a university hospital. SUBJECTS: Seven conscious, chronically catheterized, adult merino sheep. INTERVENTIONS: Epinephrine at 40 micrograms/min or dopamine at 2 micrograms/kg/min, or both drugs concurrently were infused for 4 hrs on separate study days in healthy sheep. This protocol was then repeated following the induction of sepsis after the intraperitoneal injection of 10(11) Escherichia coli, 10(12) Bacteroides fragilis, and bran. MEASUREMENTS AND MAIN RESULTS: Systemic oxygen delivery (DO2) and consumption were measured using thermodilution cardiac output and measured oxygen content. Renal blood flow was measured using an electromagnetic flow transducer, and creatinine clearance was calculated as the quotient of renal blood flow and the renal extraction ratio of creatinine. Infusion of epinephrine augmented systemic DO2 and mean arterial pressure (MAP) during both healthy and septic studies. Systemic oxygen consumption was only increased during epinephrine infusion in the septic study. During the healthy animal study, renal blood flow was initially decreased during epinephrine infusion, but increased to 36% above baseline (p = .003). However, creatinine clearance remained unchanged. During the experimental sepsis study, the infusion of epinephrine had less marked effects on renal blood flow (unchanged from baseline), while an initial reduction (15 mins) in creatinine clearance (p = .04) was not sustained and had returned to baseline by 3 hrs. Dopamine alone produced no change in systemic oxygen variables or MAP during the studies on healthy or septic animals. Although dopamine produced renal vasodilation and an increase in renal blood flow in the healthy state, these results were not found during the septic state. In addition, concurrent infusion of dopamine with epinephrine did not alter the systemic or renal effects of epinephrine during the healthy or septic states. CONCLUSIONS: These results do not support the routine use of low-dose dopamine, and demonstrate a change in renovascular responses to catecholamines during intraperitoneal sepsis. The infusion of epinephrine at 40 micrograms/min had few deleterious effects on the kidney, and augmented both MAP and systemic DO2. Its role as a catecholamine in the management of sepsis may need to be reconsidered.     

GRAPHITE AS A REFRACTORY*

(1) Some properties of graphite are discussed and industrial applications as a refractory are enumerated. (2) Previous work on graphite, particularly during the World War on graphite crucibles, is reviewed. That work was directed toward finding substitutes for imported graphites and clays. Since peace-time conditions were restored the manufacturers have returned to foreign sources of raw materials and some reasons for this tendency are advanced (3) Analyses of several foreign and domestic graphites are tabulated (4) Reports are given on experiments on the thermal conductivity of clay-graphite bodies.; with the effect of varying percentages of graphite on the conductivity.     

Phylogenetic characterization of ineffective Frankia in Alnus glutinosa (L.) Gaertn. nodules from wetland soil inoculants

Ineffective Frankia endophytes were retrieved from various wet soils by using Alnus glutinosa clones as trapping plants. No pure cultures could be isolated from these ineffective nodules. Therefore, the phylogenetic position of these endophytes was determined by sequence analysis of cloned PCR products of bacterial 16S rDNA, derived from nodules. The results showed that all nodule endophytes belong to a hitherto undescribed cluster of the Frankia phylogenetic tree. The position of these uncultured ineffective Frankia nodule endophytes is different from that of the ineffective Frankia isolates derived from A. glutinosa nodules, even when originating from the same geographical location. This suggests a bias in current isolation techniques.     

Management of pulmonary tuberculosis suspects with negative sputum smears and normal or minimally abnormal chest radiographs in resource-poor settings

SETTING: Queen Elizabeth Central Hospital, Blantyre, Malawi. OBJECTIVES: 1) To determine the proportion of pulmonary tuberculosis (PTB) suspects with negative sputum smears and a normal/minimally abnormal chest radiograph (CXR) who are culture-positive for Mycobacterium tuberculosis, and 2) to determine how many develop smear or radiographic evidence of PTB (TB CXR) during follow-up. METHODS: PTB suspects with negative sputum smears and a normal/minimally abnormal CXR were given a second course of antibiotics and followed up at 3-week intervals over 3 months with repeat sputum smears and chest radiography. RESULTS: Of 79 patients (38 men and 41 women, mean age 33 years) with negative smears and a normal/minimally abnormal CXR, 16 (21%) were culture-positive for M. tuberculosis. Of 15 culture-positive patients who were alive and attended follow-up, seven (47%) developed a TB-CXR by 3 months. Of 41 culture-negative patients who were alive and attended follow-up, 13 (32%) developed a TB-CXR, including one patient who became sputum smear-positive. TB-CXRs were found only in patients with a cough. CONCLUSION: TB suspects with negative smears and normal/minimally abnormal CXRs in high human immunodeficiency virus (HIV) prevalent countries should be given a second course of antibiotics. If cough improves, patients can be advised not to return for further follow-up. If cough continues, patients should return for further follow-up with sputum smear examination and chest radiography. Approximately 50% of those who have culture-positive PTB will develop a TB-CXR by 3 months and can be identified if radiographic facilities are available.     

Carry-over effects of dietary crude protein and triiodothyronine (T3) in broiler chickens

Indian River male broiler chickens growing from 7 to 30 d of age were fed on diets containing crude protein levels ranging from 120 to 300 g/kg plus 0 or 1 mg triiodothyronine (T3)/kg diet. The purpose of this study was to examine the effects of these treatments on lipogenesis after a common diet was fed (180 g crude protein/kg diet from 30 to 56 d of age). Dietary treatment groups were sampled at 30 and 56 d. In vitro lipogenesis was determined by incubating liver explants for 2 h at 37 degrees in Hanks' salts containing 25 mM-HEPES and 10 mM-[2-14C]acetate and then measuring acetate incorporation into total lipid. Growth and feed consumption from 7 to 30 d increased (P < 0.01) as dietary protein increased from 120 to 210 g/kg diet. Both measurements decreased as crude protein increased from 210 to 300 g/kg diet. T3 decreased (P < 0.01) growth and feed intake during this period. Low-protein (< 180 g/kg) diets increased (P < 0.05) and T3 decreased lipogenesis in 30-d-old chickens. Although birds given T3 from 7 to 30 d grew at the greatest rate from 30 to 56 d of age, the final body weight was still less than controls. In vitro lipogenesis at 56 d of age was not affected by either of the two dietary treatments. In contrast, the relative size of the abdominal fat pad (g/kg body weight) at 56 d was decreased by feeding T3 from 7 to 30 d. Any changes in metabolism elicited by either dietary protein levels or hormone treatments may be specific to the particular dosing interval and are not sustained when a common diet is fed during a repletion period.     

Characterization of fetal ovine renal dysplasia after mid-gestation ureteral obstruction

OBJECTIVE: The etiology and pathogenesis of renal dysplasia are poorly understood. To characterize the histologic changes in fetal renal dysplasia, we studied a fetal ovine model of urinary obstruction. DESIGN: Animal study. ANIMALS: Seven fetal lambs, and other lambs of the same gestational age as controls. INTERVENTIONS: Unilateral ureteral ligation on fetal lambs at approximately 70 days' gestation (term for sheep is 145 days), during nephrogenesis. Kidneys were subsequently collected, examined histologically and characterized by immunohistochemical tests involving cytokeratin antiserum and a monoclonal antibody to alpha-actin. OUTCOME MEASURES: Histologic changes in ligated fetal lamb kidneys, based on comparison with normal fetal lamb kidneys. RESULTS: At near term (140 days' gestation), the ligated kidney showed distorted and less abundant renal parenchyma than a normal control kidney. Upon microscopic examination, the ligated kidney displayed marked architectural distortion of the outer cortex, with abundant interstitial fibrosis, primitive ductules and glomeruli, and cysts of varying sizes lined by squamous and cuboidal epithelia and surrounded by a loose mesenchyme. The renal medulla contained differentiated collecting ducts, which were structurally distorted and less abundant than in normal control kidneys. The proximal and distal tubule elements were primitive and markedly underdeveloped. Cytokeratin immunoreactivity was present in the collecting duct epithelium and in the cuboidal epithelium lining many of the cortical cysts. Smooth muscle alpha-actin immunoreactivity was localized in the cortical region of the kidney, which highlighted the abundance and disorganization of the undifferentiated mesenchyme and identified the fibromuscular collars of the primitive ductules of the cortex and the distorted collecting ducts of the medulla. CONCLUSIONS: These results highlight the histologic changes resulting from unilateral ureteral ligation in fetal lambs. This model is useful in the study of the pathogenesis of fetal obstructive renal dysplasia.     

Collagen-induced arthritis in nonhuman primates: multiple epitopes of type II collagen can induce autoimmune-mediated arthritis in outbred cynomolgus monkeys

A key event in signal transduction during chemotaxis of Salmonella typhimurium and related bacterial species is the interaction between the phosphorylated form of the response regulator CheY (CheY approximately P) and the switch of the flagellar motor, located at its base. The consequence of this interaction is a shift in the direction of flagellar rotation from the default, counterclockwise, to clockwise. The docking site of CheY approximately P at the switch is the protein FliM. The purpose of this study was to identify the CheY-binding domain of FliM. We cloned 17 fliM mutants, each defective in switching and having a point mutation at a different location, and then overexpressed and purified their products. The CheY-binding ability of each of the FliM mutant proteins was determined by chemical crosslinking. All the mutant proteins with an amino acid substitution at the N terminus, FliM6LI, FliM7SY and FliM10EG, bound CheY approximately P to a much lesser extent than did wild-type FliM. CheY approximately P-binding of the other mutant proteins was similar to wild-type FliM. To investigate whether the FliM domain that includes these three mutations is indeed the CheY-binding domain, we synthesized a peptide composed of the first 16 amino acid residues of FliM, including a highly conserved region of FliM (residues 6 to 15). The peptide bound CheY and, to a larger extent, CheY approximately P. It also competed with full-length FliM on CheY approximately P. These results indicate that the CheY-binding domain of FliM is located at the N terminus, within residues 1 to 16, and suggest that FliM monomers can form a complete site for CheY binding.