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To determine the timing and location of renal cell regeneration after ischemic injury to the kidney and to assess whether exogenous epidermal growth factor (EGF) enhances this regenerative repair process to accelerate recovery of renal function, experiments were undertaken in rats undergoing 30 min of bilateral renal artery clamp ischemia followed by reperfusion for varying time intervals. Renal cell regeneration, as reflected by incorporation of radiolabeled thymidine within the kidney, began between 24 to 48 h and reached a peak at 72 h after renal ischemia. As demonstrated by histoautoradiography, renal thymidine incorporation was essentially confined to tubule cells. After the rats were killed by decapitation and exsanguination, the kidneys were quickly removed and cut longitudinally. Portions (100 mg) of the kidney were placed in cryogenic tubes and snap-frozen in liquid nitrogen. Samples were stored at -20 to -70'C for a maximum of 6 d before processing. Tissue samples were homogenized in ice-cold distilled water using a tissumizer (Tekmar Co., Cincinnati, OH). DNA was purified from 1.0 ml of homogenate. To obtain a complete time course, some animals were allowed to recover for 7 d after renal ischemia and blood samples were then obtained daily for BUN or serum creatinine measurements. Radioactivity was measured on 0.5 ml of sample in 20 ml of Safety-Solve (Research Products International Corp., Mt. Prospect, IL) in a scintillation counter (model 9000; Beckman Instruments, Inc., Fullerton, CA). Counting efficiency was estimated by an internal standard. Serum samples were counted to assure consistent intraperitoneal absorption of the [3H]thymidine. Samples of the DNA extract were counted and corrected for sample DNA content.To localize and identify the cells incorporating the radiolabeled thymidine within the kidney, histoautoradiography of kidney samples was also accomplished using methods previously published from this laboratory (5). Kidneys were perfused in vivo with 2% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.2). Tissue sections from kidneys were placed in 4% formaldehyde, 1% glutaraldehyde, 100 mM phosphate buffer (7.2). Specimens were dehydrated and embedded in methacrylate. Tissue sections (4 ,m) were dipped in NBT-2 nuclear emulsion (Eastman Kodak Co., Rochester, NY) and stored in the dark at 4°C for 21 d. The sections were developed and counterstained with Lee's methylene blue-basic fuchsin. For quantitative evaluation, a computerized operator-interactive system was used as described previously (5). Sections were examined at 176 magnification, and 10-15 fields were counted in the cortex and outer and inner stripes of the outer medulla in each section for an individual animal. The cell type of the labeled cells was identified as either tubular or interstitial.For the experiments that used EGF, rats were administered EGF (20 ,ug) subcutaneously 1-1.5 h after surgery. This dose of EGF is substantially lower than those employed in previously reported studies that administered EGF...

Nineteen malnourished chronic peritoneal dialysis patients who were ingesting a low protein intake underwent metabolic balance studies to test whether a dialysate that contained amino acids would improve their protein nutrition. Patients lived in the hospital for 35 days while they ate a constant diet and underwent their usual regimen of continuous ambulatory peritoneal dialysis (CAPD). The first 15 days served as a Baseline Phase. For the last 20 days, the usual dialysate was substituted with a dialysate of essentially the same composition except that it contained 1.1% essential and nonessential amino acids and no glucose. Patients received one or two dialysate exchanges with amino acids each day depending on the amount necessary to bring the individual's dietary protein plus dialysate amino acid intake to 1.1 to 1.3 g/kg body weight/day. During Baseline, patients were in neutral nitrogen balance; net protein anabolism was positive, as determined from 15N-glycine studies. After commencing intraperitoneal amino acid therapy, nitrogen balance became significantly positive, there was a significant increase in net protein anabolism, the fasting morning plasma amino acid pattern became more normal, and serum total protein and transferrin concentrations rose. Patients generally tolerated the treatment well, although some patients developed mild metabolic acidemia. These findings indicate that a dialysate containing amino acids may improve protein malnutrition in CAPD patients ingesting low protein intakes.

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Key Points Question What are the characteristics and mortality outcomes associated with COVID-19 among Medicare patients undergoing long-term dialysis? Findings This cohort study among 498 169 patients receiving regular maintenance dialysis found several risk factors for COVID-19 that persisted as risk factors for mortality: nursing home status, time on dialysis, congestive heart failure, diabetes, and comorbidity burden. Higher COVID-19 rates were observed among Black patients, while attenuated survival differences were observed between Black and non-Black patients, and although male sex was not associated with a higher COVID-19 rate, it was associated with higher mortality among patients with COVID-19. Meaning These findings suggest that among patients undergoing long-term dialysis, Black race, male sex, nursing home status, and having comorbidities, such as diabetes and cardiac diseases, were associated with higher risk of COVID-19 and higher post–COVID-19 mortality.

Purpose To determine if a slight modification of the 1987 Eaton-Glickel staging and interpreting 4 standardized radiographs for trapeziometacarpal arthritis improved analysis, to determine if a quantifiable index measurement from a single Robert (pronated anteroposterior) view enhanced reproducibility, and to examine whether improved radiographic staging correlated to clinically relevant disease and thus support validity. Methods We analyzed 4 thumb radiographs (posteroanterior, lateral, a Robert, and stress views) in 60 consecutive subjects representing an adult population spectrum of asymptomatic to advanced disease. Two experienced hand surgeons, 1 chief resident, and 1 medical student performed the analysis on each subject’s radiographs. We analyzed all 4 radiographs for Eaton and modified Eaton staging and then later analyzed only the Robert view for the thumb osteoarthritis (ThOA) index measurement. The radiographs were randomized and re-read a week later for each classification at separate times. Surgically excised trapeziums from 20/60 subjects were inspected for first metacarpal surface disease and correlated to the 3 classifications. Results All 3 staging classifications demonstrated high reproducibility, with the intraclass correlation coefficient averaging 0.73 for the Eaton, 0.83 for the modified Eaton, and 0.95 for the ThOA index. Articular wear and metacarpal surface eburnation correlated highest to the ThOA index, with advanced disease ≥ 1.55 correlating to Eaton III/IV and modified Eaton stage 3/4 in a linear relationship. Discussion The ThOA index based on a Robert view provided a measurable alternative to Eaton staging and correlated to severity of surgically relevant thumb TMC OA. Clinical Relevance A simple reproducible radiographic measurement may enhance TMC OA classification and provide a reliable means to predict clinical disease. Level of Evidence Level of Evidence II/Diagnostic

The present report describes more than nine years of experience with simultaneous removal and replacement of the chronic peritoneal dialysis (PD) catheter in treating refractory mechanical and infectious complications. Simultaneous catheter replacement and removal not only succeeded in 22 of 23 cases with non-infectious mechanical complications, allowing uninterrupted PD in all but three, but also succeeded in 30 (83%) of 36 additional cases with persisting or recurring infection. Simultaneous procedures failed in six (17%) of 36 infectious cases, due to persistent infection in two cases and to procedure complications in four cases. The clinical characteristics of the 30 successful infectious cases were compared to the characteristics of both the six failures, as well as 29 additional infectious cases in which the peritoneal catheter was removed but was not replaced because of a variety of serious complications (such as pancreatitis, abscess, sepsis, or fluid overload). At the time of simultaneous catheter replacement in successful cases, temporary control of active peritoneal inflammation was achieved more frequently (80% vs. 31%, P less than 0.001) with a shorter interval of antibiotic coverage (6.4 +/- 0.9 vs. 14.7 +/- 1.3 days, P less than 0.001). In addition, the successful cases were characterized by significantly more Staphylococcal infections (70% vs. 26%, P less than 0.001) and significantly fewer Pseudomonal or fungal infections (6% vs. 59%, P less than 0.001), although successful cases included some non-Pseudomonal, non-enteric gram negative infections (23%).(ABSTRACT TRUNCATED AT 250 WORDS)

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