Adipsic hypernatremia complicated by hyponatremia.
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Adult↗
Biomedical subjects
D J Hirsch
Publications and source records attributed to D J Hirsch.
In vitro activity of tosufloxacin (A-61827; T-3262) against selected genital pathogens.
The in vitro activity of tosufloxacin (A-61827; T-3262) against 15 clinical isolates of Chlamydia trachomatis and 31 recent clinical isolates of Neisseria gonorrhoeae, including 15 spectinomycin-resistant N. gonorrhoeae and 16 penicillinase-producing N. gonorrhoeae, was determined. Tosufloxacin was compared with doxycycline, ciprofloxacin, and temafloxacin against C. trachomatis. Susceptibility testing was performed by using McCoy cell monolayers. The in vitro activity of tosufloxacin against N. gonorrhoeae was compared with that of ciprofloxacin, temafloxacin, doxycycline, ceftriaxone, and spectinomycin by using an agar dilution method. Tosufloxacin was as active as temafloxacin against C. trachomatis (MIC for 90% of strains tested [MIC90], 0.25 microgram/ml; MBC for 90% of strains tested [MBC90], 0.25 microgram/ml) and was almost as active as doxycycline (MIC90, 0.06 microgram/ml; MBC90, 0.125 microgram/ml). Ciprofloxacin, temafloxacin, and tosufloxacin were extremely active against N. gonorrhoeae, including spectinomycin-resistant N. gonorrhoeae and penicillinase-producing N. gonorrhoeae, with MIC90s of 0.004, 0.015, and 0.008 microgram/ml, respectively. Ceftriaxone was slightly less active (MIC90, 0.03 microgram/ml), and doxycycline was the least active drug tested (MIC90, 4.0 micrograms/ml). Tosufloxacin and temafloxacin had excellent activity against the C. trachomatis and N. gonorrhoeae strains tested.
4-Quinolones↗
Adenylate cyclase uncoupled beta-adrenergic receptors in salamander proximal tubules.
The isolated perfused proximal tubule of the neotenic salamander Ambystoma tigrinum responds with either a hyperpolarization or depolarization of both the basolateral cell membrane and transepithelial potentials following the addition of 10(-5) M isoproterenol to the bath superfusate. Both responses were blocked by 10(-6) M propranolol but neither response was mimicked by 10(-4) M cAMP. beta-Adrenergic binding studies of individual microdissected proximal tubules using (-)-[3H]CGP-12177 as a hydrophyllic radioligand and (+/-)-timolol (0.1 mM) as the displacer drug revealed two distinct populations of proximal tubules possessing either low (KD = 153.8 nM; Bmax = 110.2 fM/mm) or high affinity (KD = 12.0 nM: Bmax = 3.9 fM/mm) binding characteristics. Competition studies indicated that the bound (-)-[3H]CGP-12177 behaved as a typical beta-adrenergic ligand, being displaced by (-)-isoproterenol but not by (+)-isoproterenol or (-)-phenylephrine. However, neither appeared to be coupled to the adenylate cyclase system. These data suggest the presence of functional beta-adrenergic receptors that do not appear to be coupled to the adenylate cyclase system.
Adenylyl Cyclases↗
Hyperkalemia and hypertension: is this a "chloride-shunt" disorder?
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Acidosis↗
A comparative study of the nephrotoxicity of iohexol, iopamidol and ioxaglate in peripheral angiography.
Iohexol (Omnipaque 350) and iopamidol (Isovue 370) are nonionic monomers; ioxaglate (Hexabrix 320) is an ionic dimer. We compared the nephrotoxicity of these three media by a prospective double-blind evaluation in 500 patients who underwent peripheral angiography during a 6-month period. Serum creatinine levels were determined before injection of the contrast medium and 72 hours after in 478 patients. In 308 (64%) patients there was an average increase in the serum creatinine level of 18.1 mumol/L after injection of an average volume of 123 ml of contrast medium. A subset of 80 patients who had an elevated baseline creatinine level (more than 110 mumol/L) had an average increase in the serum creatinine level of 40.45 mumol/L. Of patients who had arterial injections, 182 (72%) had an increase in serum creatinine level (20.7 mumol/L), but of those who had peripheral venous injections, only 43 (45%) had an elevated creatinine level (9.2 mumol/L), and of those who had central venous injections, 83 (63.8%) had an elevated level (17.0 mumol/L). In most patients elevation of the serum creatinine level was not of clinical importance. High-risk patients with an elevated serum creatinine level were found to be most vulnerable to contrast nephrotoxicity. Although mean differences were not statistically significant, there were consistent trends which suggested that ioxaglate was the least nephrotoxic of the three agents studied.
Acute Kidney Injury↗
Epinephrine and dDAVP administration in patients with congenital nephrogenic diabetes insipidus. Evidence for a pre-cyclic AMP V2 receptor defective mechanism.
We recently showed that the administration of the antidiuretic V2 specific agonist, 1-desamino[8-D-arginine]vasopressin (dDAVP), to seven male patients with congenital nephrogenic diabetes insipidus (CNDI) did not cause a decrease in blood pressure nor an increase in plasma renin activity or factor VIIIc or von Willebrand factor release. In normal subjects, plasma renin activity, coagulation factors and plasma cyclic AMP are stimulated not only by dDAVP but also by the administration of epinephrine. In the present study, we measured tissue plasminogen activator (activity and antigenicity), von Willebrand factor multimers, plasma and urinary cyclic AMP concentrations following dDAVP or epinephrine administration. We infused epinephrine into three male patients with CNDI. Factor VIIIc and tissue plasminogen activator augmented by 75 to 100% and von Willebrand Factor multimers were increased; plasma renin activity and plasma cyclic AMP concentration increased by 200%. None of these values changed when the same subjects as well as eleven other male patients with CNDI received dDAVP. Furthermore, dDAVP administration increased plasma cyclic AMP concentrations in normal subjects, but not in 14 male patients with CNDI. These results demonstrate the specificity of the extrarenal V2 receptor defect expressed in our patients. The lack of a plasma cyclic AMP response to the administration of dDAVP would suggest an altered pre-cyclic AMP stimulation mechanism.
Adult↗
Low-sodium environment induces adaptation in salamander diluting segments.
The urodele Ambystoma tigrinum adapts to a distilled water environment by decreasing renal sodium excretion, but the site and mechanism of renal adaptation is unknown. Isolated diluting segments of Ambystoma kidney were studied after a 2-wk exposure of the animals to either distilled or artificial pond ([Na] = 1.2 meq/l) water. Identification of diluting segments was confirmed by electron microscopy. Morphometric study revealed evidence of increased tubular diameter and cellular hypertrophy in the distilled water group. Na+-K+-ATPase activity was increased in tubules from the distilled water group compared with tubules from the pond water group; 40.2 +/- 6.9 vs. 21.7 +/- 4.3 nM ADP generated.min-1.mm tubule length-1, P less than 0.036. This alteration in ATPase activity was due to an increase in the number of pump units present on the basolateral membrane, since specific ouabain binding was also doubled in distilled water compound with pond water group tubules, 20.7 +/- 2.3 vs. 9.1 +/- 0.9 fmol/mm tubule length tubules, P less than 0.011. An increase in transepithelial potential difference of the diluting segment was noted in distilled water group tubules (19.5 +/- 1.4 mV) compared with tubules in the pond water group (13.2 +/- 1.8 mV), P less than 0.015. We conclude that distilled water adaptation is associated with specific diluting segment structural and functional alterations, which are probably linked to an increase in sodium transport rate.
Acclimatization↗
Death from dialysis termination.
The only detailed analysis of dialysis termination by viable patients was reported by Neu and Kjellstrand (N Engl J Med 1986; 314: 14-20) from the USA. We analysed a similar series from Halifax, Nova Scotia, to add to our understanding of this important mode of treatment rejection by dialysis patients. Of 178 chronic dialysis patients at risk from January 1982 to May 1987, 11 viable patients (6%) stopped dialysis (16% of all patient deaths) after a mean of 22 +/- 7 months of therapy. Mean age at death was 67 +/- 5 years. The majority of these patients were receiving in-centre haemodialysis. Six patients independently decided to stop therapy, while in three cases physicians first proposed termination. In only two cases did the family propose termination. All patients died in hospital a mean of 10 +/- 2 days after the last dialysis. Dementia was the reason for stopping treatment in only two cases, while chronic heart failure with poor exercise tolerance was the major precipitant. One patient suffered from diabetes mellitus. We were not able to differentiate patients terminating therapy from those continuing treatment on the basis of age or co-morbidity, suggesting that subjective patient perception of their condition is a critical factor in stopping dialysis.
Adaptation, Psychological↗
Response of collecting tubule cells to aldosterone and potassium loading.
To investigate the sites of action of aldosterone (Aldo) and chronic potassium loading (high K) and to determine whether dietary K can modulate collecting duct structure independent of Aldo, a morphometric study of the structure of the initial collecting tubule (ICT), the cortical collecting tubule (CCT), the medullary collecting duct in the outer stripe (MCDOS) and the inner stripe (MCDIS), and the papillary collecting duct (PCD) was carried out in a rat model in which plasma levels of Aldo were clamped at basal or physiologically elevated levels and high K could be induced without concomitant hyperaldosteronism. Elevated levels of Aldo increased cell area (Ac) and basolateral membrane surface (BLM) from control values in the ICT, CCT, and MCDOS but not in the MCDIS or PCD. High K with normal physiological levels of Aldo increased BLM in the ICT and CCT without a concomitant change in AC. No response was seen in MCDOS, MCDIS, or PCD. It is concluded that Aldo can modulate principal cell structure in the collecting duct system in segments extending from the ICT through the MCDOS in the rat and that high K independent of Aldo can influence collecting duct structure only in the ICT and CCT.
Aldosterone↗
Effect of adrenalectomy on distal tubule water permeability of the Brattleboro rat.
The mechanism of impaired water excretion in adrenalectomized mammals is unclear. Previous workers have suggested that one cause might be increased water permeability of the distal nephron, allowing back diffusion of water from tubular fluid diluted by the ascending limb. Evidence to support this mechanism in previous studies has been confounded by simultaneous changes in steroid and antidiuretic hormone levels. We compared osmotic and diffusional water permeability of the surface late distal tubule in vivo in intact and adrenalectomized Brattleboro rats, which are free of antidiuretic hormone. The adrenalectomized rats were demonstrated to have impaired diluting capacity in clearance studies. Adrenalectomized rats had a sixfold increase in osmotic permeability and a 1.5-fold increase in diffusional permeability over intact controls. Adrenal steroids have a specific action on water permeability of the distal nephron, independent of antidiuretic hormone.
Adrenalectomy↗
Limited-protein diet: a means of delaying the progression of chronic renal disease?
Recent studies suggest that restricting the dietary protein intake of patients with progressive renal disease slows their loss of renal function. Studies in animals have shown that an increase in the filtration rates of individual nephrons (hyperfiltration), an adaptive response to loss of renal mass, appears to induce progressive renal damage and that such damage may be prevented by dietary protein restriction. Preliminary evidence suggests that restriction of protein intake to less than 50 g/d in man has a similar beneficial effect in slowing the progression of chronic renal disease. Dietary therapy appears to be particularly effective for patients with early renal disease, allowing a doubling in the time until dialysis is required in many cases. Although large-scale clinical studies are planned, there is now sufficient evidence to warrant the use of moderate protein restriction (to less than 50 g/d) in most patients suffering from progressive renal disease. Such therapy should only be instituted with expert dietary and nephrologic consultation.
Adult↗
Effect of central air conditioning and meteorologic factors on indoor spore counts.
We have studied the effect of residential central air conditioning on indoor spore counts. The air of 6 pairs of homes (air-conditioned and non-air-conditioned) was sampled volumetrically 4 times daily for 3 consecutive days at 2-hr intervals in the kitchens, bedrooms, and basements with an Anderson sampler. Nearly simultaneous samples were taken outdoors at the same intervals. The total spore count was significantly lower (p less than 0.05) in the kitchens and bedrooms of air-conditined as compared to non-air-conditioned homes. Logarithmic conversion of the total spore count showed significant reduction in all indoor locations of air-conditioned homes. Multiple regression analysis revealed the lower relative humidity of air-conditioned homes to be associated with the lower spore counts. There was no difference in the percent concentration of the major genera within both types of homes. Since reducing the influx of outdoor spores decreases the total spore count without altering the relative concentration of the genera whereas filtration preferentially removes the larger spores, we conclude that the major mechanism in reducing spore counts in air-conditioned homes is the closed windows, although the lower relative humidity and perhaps filtration are also associated with lower spore counts.
Air Conditioning↗
Resource utilization for peritoneal catheter placement.
We reviewed hospitalization data for our large regional peritoneal dialysis (PD) program between January 1, 1997, and November 30, 1998, to determine the impact of inpatient PD catheter placement, by using Toronto Western II catheters placed under general anesthesia. Of 106 catheter placements, 80 were elective in previously identified renal failure patients. In elective cases, mean length of hospital stay was 6.75 days (SD, 7.01), median 4.5 days. These Canadian data are similar to those from the American Health Cost and Utilization Project. Evidently surgical PD catheter placement even in elective, planned circumstances involves a significant use of hospital resources. Current published reports do not outline hospital resource requirements or complication rates for this method.
Catheters, Indwelling↗
Progressive increases in peritoneal dialysis prescription: patient acceptance and complication rates.
Peritoneal dialysis adequacy has an impact on patient mortality. Both the CANUSA study and DOQI Guidelines outline targets for adequacy, and it has been suggested that quantitative adequacy determinations be made at regular intervals. Some groups believe these targets are not achievable because of lack of patient acceptance and high complication rate. We examined the outcome of peritoneal dialysis in a setting where prescription changes are made on clinical grounds, and determined the complication rates and patient acceptance of prescription changes. A total of 154 patients commencing peritoneal dialysis from January 1, 1994,-December 31, 1996, were studied to determine reasons for dialysis prescription changes, patient acceptance of, and complications related to these changes. Point prevalence data for dialysis prescription for our center and other Canadian centers were obtained from the Canadian Institute for Health Information. Co-morbidity - adjusted patient and technique survival for our center versus other centers in Canada was performed by Poisson regression analysis. Dialysis prescription changes were based on clinical assessment. A total of 102 patients started on either > 8 L of dialysate or had an increase in dialysis prescription during the study period. These patients were heavier, on peritoneal dialysis for longer, and fewer were transplanted compared with the patients on standard prescription (8 L or less). Only 4% of patients refused the change in dialysis prescription, and only 13 peritoneal leaks occurred, resulting in 3 transfers to hemodialysis. Our center prescribed a larger number of exchanges than other Canadian centers in 1995-1997. Adjusted mortality rate ratios for our center versus the other Canadian Centers (1990-1996) are equal. The 3 year technique survival for peritoneal dialysis patients from our center between 1990-1996 was 75% vs. 61% for other centers in Canada. At last follow-up, > 60% of patients had a Kt/V urea >2.1 and 45% had a creatinine clearance > 70 L/1.73 m2/week. This Regional Program has successfully prescribed high volume and frequency peritoneal dialysis on clinical grounds alone. This practice is associated with high patient acceptance, equivalent mortality, and higher technique survival compared with the rest of Canada.
Aged↗
Rapidly progressive glomerulonephritis during antituberculous therapy.
Within 3 weeks of beginning continuous daily isoniazid and rifampin therapy for pulmonary tuberculosis, a patient developed acute renal failure. Renal biopsy demonstrated lesions characteristic of rapidly progressive glomerulonephritis with minor interstitial changes. Prior reports have emphasized the tubular and interstitial lesions associated with intermittent or discontinuous rifampin therapy for tuberculosis. This report documents the occurrence of severe glomerular pathology associated with continuous, daily antituberculous therapy. The spectrum of renal lesions occurring during antituberculous therapy, particularly in association with rifampin, may be wider than previously suspected.
Acute Kidney Injury↗
Long-term peritoneal dialysis in the absence of residual renal function.
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Anuria↗