H. William Harris

Vasopressin-elicited water and urea permeabilities are altered in IMCD in hypercalcemic rats

To investigate how hypercalcemia blunts renal concentrating ability, alterations in basal and arginine vasopressin (AVP)-elicited osmotic water ( P f) and urea ( P urea) permeabilities were measured in isolated perfused terminal inner medullary collecting ducts (IMCD) from control and chronically hypercalcemic rats after dihydrotachysterol (DHT) (M. Levi, L. Peterson, and T. Berl. Kidney Int. 23: 489-497, 1983) treatment. The IMCD P f of DHT-treated rats did not increase significantly after AVP and was accompanied by a significant 87 ± 4% reduction in aquaporin-2 (AQP-2) protein but not mRNA. In contrast, both basal and AVP-elicited IMCD P urea from DHT rats were significantly increased and accompanied by a significant 41 ± 11% increase in AVP-regulated urea transporter protein content. Immunoblotting with anti-calcium/polyvalent cation-sensing receptor protein (CaR) antiserum revealed specific alterations in CaR bands in endosomes purified from the apical membranes of inner medulla of DHT rats. These data are the first detailed analyses of hypercalcemia-induced alterations in AVP-regulated permeabilities and membrane transporters in IMCD. We conclude that selective alterations in IMCD transport occur in hypercalcemia, permitting the body to dispose of excess calcium without forming calcium-containing renal stones.

Hamman-Rich syndrome: Report of a case diagnosed antemortem by lung biopsy and successfully treated with long-term cortisone therapy

Abstract 1.1. A case of Hamman-Rich syndrome diagnosed by lung biopsy is presented. 2.2. The patient is symptomatically well and x-ray of the chest is virtually normal eight and one-half months after initiation of continuous cortisone therapy. 3.3. This case demonstrates the longest clinical remission induced by therapy reported in the literature.

The mouse polycystic kidney disease mutation (cpk) is located on proximal chromosome 12

The mouse congenital polycystic kidney (cpk) mutation produces a condition that resembles human autosomal recessive polycystic kidney disease (ARPKD) in its pattern of inheritance, clinical progression, and histopathology. Inheritance of this mouse mutation in crosses segregating the Rb(12.14)8Rma translocation chromosome and various DNA markers of Chromosome 12 have localized cpk to a site near D12Nyu2, approximately 7 cM from the centromere of Chromosome 12. This result suggests that the homologous PKD2 gene should be localized to either human chromosome 2p23-p25 or chromosome 7q22-q31.

The Perinatal Expression of Aquaporin-2 and Aquaporin-3 in Developing Kidney

The kidney provides an important contribution to permit the fetus to successfully transition to an independent existence by production of urine with significantly different osmolality compared with plasma. Although recent work has uncovered many aspects of the maturation and regulation of the renal concentrating and diluting mechanism, understanding of how alterations in the expression of aquaporin (AQP) water channels contribute to the formation of urine in the perinatal period is incomplete. Here, we report that both AQP-2 and -3 are expressed during fetal life as early as embryonic d 18 in ureteric buds of rat kidneys, where each is localized to the apical and basolateral membranes of epithelial cells, respectively. Northern analyses demonstrate that the 1.9-kb AQP-2 transcript is present in fetal and postnatal rat kidneys similar to that observed in adults. AQP-2 mRNA expression increases after d 3 of postnatal life. Immunoblotting reveals an increase in total kidney AQP-2 protein particularly with respect to its glycosylated form after postnatal d 3. AQP-3 protein also exhibits a similar alteration likely due to a similar increase in its glycosylation state. Both AQP-2 and AQP-3 display a distribution in the collecting ducts of human postnatal infants and adults identical to that exhibited in rat kidneys. These data show that both AQP-2 and -3 are present in collecting duct epithelia of fetal and postnatal kidneys. Thus, the reduced AVP-responsiveness and decreased urinary concentrating ability of the kidney during the fetal and immediate postnatal period does not appear to be caused by lack of AQP-2 or AQP-3 proteins.

Calpain-mediated AQP2 proteolysis in inner medullary collecting duct

Vitamin D-elicited hypercalcemia/hypercalciuria is associated with polyuria in humans and in animal models. In rats, dihydrotachysterol (DHT) induces AQP2 water channel downregulation despite unaltered AQP2 mRNA expression and thus we investigated the mechanism of AQP2 degradation. Incubation of AQP2-containing inner medullary collecting duct (IMCD) endosomes with Ca(2+) or calpain elicited AQP2 proteolysis, an effect abolished by leupeptin. This endogenous, Ca(2+)-sensitive protease activity exhibited a different proteolytic digest pattern from trypsin, which also degraded AQP2 in vitro. IMCDs contain abundant micro-calpain protein and functional calpain proteolytic activity as demonstrated by immunohistochemistry, immunoblotting, and gel zymography. Furthermore, by small particle flow cytometry we demonstrated that micro-calpain colocalizes with apical IMCD endosomes. DHT does not appear to elicit general proteolysis, however, in addition to AQP2 degradation, DHT treatment also diminished micro-calpain and calpastatin expression although whether these changes contributed to the AQP2 instability remains unclear. Together, these data show for the first time that AQP2 is a substrate for calpain-mediated proteolysis and that furthermore, micro-calpain, like AQP2, is both highly expressed in renal inner medulla and localized to apical IMCD endosomes.

Treatment of Pneumococcal Pneumonia with Penicillin

ALTHOUGH the sulfonamide drugs are highly effective in the treatment of the pneumococcal pneumonias, serious problems sometimes arise in their administration. In patients with underlying cardiac or...

Streptomycin treatment of urinary tract infections, with special reference to the use of alkali.

T HERE are a number of reports on the streptomycin treatment of urinary tract infections caused by susceptible gram-negative organisms.‘-9 The clinical results have been quite variable. Some authors have advocated alkalinization of the urine during streptomycin therapy,8~10*11 but to date there have been no convincing data to indicate that the clinical results of streptomycin therapy are favorably influenced by alkalinization of the urine. The purpose of this report is to present clinical and bacteriological observations in twentyone streptomycin-treated patients with urinary tract infections, of whom fourteen were also treated with alkalis.

Pulmonary dysplasia, Denys-Drash syndrome and Wilms tumor 1 gene mutation in twins

Abstract While a genetic basis for the association of developmental lung and kidney defects has been suspected, the involvement of specific genes in this process is under active investigation. We report such a possible genetic linkage present in identical twins with a mutant Wilms tumor (WT1) gene. Twin girls, born at 35 weeks gestation, manifested symptoms of congenital nephrotic syndrome, renal failure, and severe respiratory abnormalities refractory to assisted ventilation. Both died at 1 month of age. Renal biopsies and autopsy kidney tissue from both the girls revealed diffuse mesangial sclerosis (DMS). Autopsy lung tissue revealed pulmonary dysplasia and hypoplasia in both twins. The WT1 gene from renal tissue in both twins was analyzed for mutations using polymerase chain reaction (PCR) amplification and the single-strand conformation polymorphism (SSCP) technique. Both twins possessed an identical missense mutation in exon 8 of the WT1 gene, resulting in replacement of arginine by histidine at amino acid 366 (arg366his) in the WT1 protein. This mutation has previously been described in Denys-Drash syndrome. The WT1 gene plays a role in mesenchymal epithelial (ME) interactions in the developing urogenital system, and possibly has a similar role during lung morphogenesis. We propose that this WT1 gene mutation contributes to both DMS and developmental pulmonary abnormalities by altering ME interactions in both organs.

Micro quantitative Edman manual sequencing

A manual Edman technique is described which allows sequential quantitative determination of from 3 to 10 amino terminal residues on quantities of peptides or proteins down to one nanomole. This is achieved by a fast, efficient method of obtaining the anilinothiazolinone or phenylthiohydantoin amino acid, and quantitating by either back hydrolysis and amino acid analysis or by a new, rapid, high resolution, quasi-isocratic, high-pressure liquid chromatographic procedure. The overall method has been extensively tested successfully on both peptides and proteins of known and unknown amino-terminal sequence and the results included here. In addition, a wide variety of applications relevant to primary structure analysis such as sequencing blocked polypeptides, use of denaturing agents as coupling buffers, reduction of protein or peptide losses on consecutive sequencing and peptide mixture analysis are all incorporated in the methodology outlined.

CHOICE OF ANESTHETIC AGENTS FOR INTRAVENOUS REGIONAL ANESTHESIA

The choice of any anesthetic agent must be made on the basis of two factors, effectiveness and safety. The safety factor must always be paramount, and this is especially true in dealing with the intravenous administration of an anesthetic agent, since removal of the agent once administered is not practical. The importance of effectiveness is obvious. In addition to considering the use of different drugs for the production of intravenous regional anesthesia, one also has the variables of the total dose given, the concentration used, and any other factors which might influence the effectiveness, toxicity, or both, such as pre-injection ischemia of the limb. I will have more to say about pre-injection ischemia later in the paper, but a word of introduction here is in order. We have studied extensivelylsg the influence on the effectiveness of a period of total ischemia of the l i b prior to injection of the local anesthetic agent of a given dose. It is clear from all of our studies that some factor associated with the metabolic changes secondary to the ischemia enchances the effectiveness of the drug in producing anesthesia or, stated conversely, the effective dose level can be reduced by using a period of prior isolation of the limb from the systemic circulation. In a series of 312 subjects, both patients and volunteers, we have studied these variables in connection with three agents; namely chlorprocaine, lidocaine, and prilocaine. The onset and effectiveness of anesthesia, the central nervous system signs and symptoms of toxicity, the response of the cardiovascular system, and, in the case of prilocaine, the appearance of methemoglobinemia, were all studied. Serial blood level determinations of each of the three agents were carried out. The effectiveness of the anesthesia was graded as follows: The loss of all sensory modalities, including touch, pin prick, deep pressure and pain sensation, accompanied by a marked or total paralysis and associated with the absence of pain or discomfort during the operative procedure, constituted