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J S Rodman

Publications and source records attributed to J S Rodman.

At least 37 records · Page 2Linked to original sources
PubMed1984

A randomized double-blind study of acetohydroxamic acid in struvite nephrolithiasis.

We studied the effects of the bacterial urease inhibitor acetohydroxamic acid on the growth of struvite stones in the urinary tract. Eighteen patients who received acetohydroxamic acid (15 mg per kilogram of body weight per day, in divided oral doses) for a mean of 15.8 months were compared in a randomized double-blind study with 19 patients who received placebo for a mean of 19.6 months. Seven patients given placebo reached a pre-determined end point: a 100 per cent increase in the two-dimensional surface area of their stones. No patient who received acetohydroxamic acid had a doubling of stone size (P less than 0.01). Nine patients receiving the drug and one patient receiving placebo required a decrease in dosage or cessation of treatment because of adverse effects (P less than 0.01). Episodes of tremulousness (n = 5, P less than 0.05), which reversed with a decrease in drug dose, and phlebothrombosis (n = 3, P not significant) were limited to the group given acetohydroxamic acid. We conclude that acetohydroxamic acid effectively inhibits the growth of struvite stones in the short term in patients infected with urea-splitting bacteria, but the prevalence of adverse reactions appears to be high and the toxicity and effectiveness of long-term therapy for struvite nephrolithiasis remain to be defined.

Adult↗
PubMed1984

Presence of an extensive clathrin coat on the apical plasmalemma of the rat kidney proximal tubule cell.

The nature of the cytoplasmic coat present on the apical invaginations of the kidney proximal tubule cell was investigated by immuneoverlay and immunocytochemistry of renal brush borders with anticlathrin antibodies. When kidney cortex was prepared for electron microscopy using methods that enhance visualization of clathrin coats, the apical invaginations at the base of the brush border microvilli were seen to be backed by a nearly continuous coating which resembles but is more extensive than the lattice-like clathrin coats found around brain coated vesicles. When isolated brush border fractions were prepared under conditions that preserve the coats, separated by SDS PAGE, and transferred to nitrocellulose, the presence of clathrin heavy and light chains was detected by immuneoverlay using two different affinity-purified anticlathrin IgGs--one that we prepared, which detects only the clathrin light chains, and the other, prepared by Louvard et al. ( Louvard , D., C. Morris, G. Warren, K. Stanley, F. Winkler , and H. Reggio , 1983, EMBO [Eur. Mol. Biol. Organ.] J., 2:1655-1664), which detects both the heavy and light chains. As viewed by light microscopy (immunofluorescence or immunoperoxidase), staining with both anticlathrins was concentrated at the base of the proximal tubule microvilli. Immunoelectron microscopic localizations carried out on brush border fractions (using peroxidase and gold conjugates) demonstrated specific binding of anticlathrin IgGs to the lattice-like cytoplasmic coat. When brush border fractions were reacted with monoclonal antibodies prepared against gp330 and maltase, proteins that serve as markers for the membrane of the apical invaginations and microvilli, respectively ( Kerjaschki , D., L. Noronha - Blob , B. Sacktor , and M. G. Farquhar , 1984, J. Cell Biol., 98:1505-1513), the two proteins retained their restrictive distribution in the brush border. The findings demonstrate (a) that the cytoplasmic coat of the proximal tubule intermicrovillar apical invaginations is composed of clathrin heavy and light chains, and (b) that the differential distribution of proteins in these two brush border microdomains is maintained in appropriately prepared brush border fractions.

Animals↗
PubMed1984

The effect of dietary protein on cystine excretion in patients with cystinuria.

Seven patients with homozygous cystinuria were studied on a metabolic ward to determine the effect of dietary manipulation on urinary cystine excretion. Isocaloric diets were calculated based on body weight and activity. Balance studies were performed for 5 days on a low protein diet (9.4 +/- 1.0% total calories) with equal amounts of animal and plant protein sources and an additional 5 days on a high protein (27 +/- 3.0% of total calories) with 70% animal protein. A significant (p less than 0.01) decrease in the excretion of 1/2-cystine, histidine, 3-methylhistidine, 1-methylhistidine, lysine, and ornithine plus arginine occurred on the low protein diet. The mean excretion of 1/2-cystine on the high protein diet was 6.13 +/- 1.48 mMoles per 24 hours which decreased to 4.89 +/- 1.06 mMoles per 24 hours on the low protein diet (p less than 0.001). Thirty seven percent of urine collections during the study were less than 2 liters/24 hours despite the fact that patients were encouraged to drink enough fluid to make 3 liters of urine/24 hours. For patients whose customary diet is high in animal protein, a more vegetarian diet may significantly reduce urinary cystine excretion. Cystine excretion in patients with cystinuria may be significantly different from day to day if animal protein consumption is variable.

Adolescent↗
PubMed1983

Partial dissolution of struvite calculus with oral acetohydroxamic acid.

Most staghorn calculi occur in patients who have chronic urinary tract infections with urea-splitting organisms. Acetohydroxamic acid, an inhibitor of the bacterial urease enzyme, is currently undergoing clinical trials to determine whether or not it can prevent stone growth in patients at risk. We report on a patient whose stones grew while she was taking placebo and then decreased in size when she took the active drug.

Administration, Oral↗
PubMed1983

Induction of expression of the rat G5 nervous system antigen occurs postnatally.

G5 is a cell membrane component found in high levels in the adult rat central nervous system and in low levels on some cells of the rat immune system. Binding assays with adult brain particulate protein preparations and monoclonal antibody to G5 (G5-IgG) gave highest activity in cerebral cortex and lowest in the white matter rich regions pons and spinal cord. Three peripheral nervous system components had no G5 activity. Analysis of G5 content in particulate protein preparations from whole rat brain of ages embryonic day 15 to adult indicates that G5 is present in negligible amounts in the newborn rat. It increases in both specific and total activity to reach adult levels by postnatal day 30. A similar induction curve was observed with cerebellum samples. In adult cerebellum, high levels of G5 were found in the molecular layer using both autoradiographic and immunofluorescence techniques. White matter had essentially no activity. The density and uniformity of reaction product in these techniques suggest that G5 is present on a major cellular constituent of the molecular layer. Pharmacologic experiments indicate G5 is not detectable on climbing fibers or adrenergic fibers. Cerebellar samples from juvenile rats also had predominant G5 activity in the forming molecular layer.

Animals↗
PubMed1981

Symptomatic hypokalemia resulting from surreptitious diuretic ingestion.

We report five cases of symptomatic hypokalemia caused by surreptitious diuretic ingestion. A positive diagnosis was made in four patients by a colorimetric detection of the diuretic in urine by simple chemical means. Patients who surreptitiously ingest diuretics appear to be mainly women, among whom there appears to be high prevalence of diagnoses involving the reproductive system. Many of these patients have health-related occupations. They seem to be very concerned with appearing obese or edematous. A high urine potassium level in the presence of a low serum potassium level can suggest this diagnosis.

Adult↗
PubMed1981

A new antigen common to the rat nervous and immune systems: II. Molecular characterization.

G5-IgG is a monoclonal antibody that binds specifically to some cells and tissues of the adult rat nervous and immune systems. The molecular nature of the G5 antigen from adult rat brain is described in this paper. G5 antigen in adult rat brain membrane fractions was trypsin-sensitive and heat-labile but not chloroform/methanol-soluble. It was solubilized by the nonionic detergent NP40 but not by 3 M KCl. Detergent-soluble rat brain particulate protein inhibited G5-IgG binding to glutaraldehyde-fixed rat brain particulate protein. Inhibitory activity could be removed by prior incubation with concanavalin-A agarose beads. Immunoprecipitates of enzymatically iodinated, detergent-solubilized brain particulate protein gave a single band on polyacrylamide gels of apparent molecular weight 95,000--105,000 daltons. A band of identical molecular weight was visualized in gels of unlabeled immune precipitates by 125I-concanavalin A. These results strongly suggest that G5 is an integral membrane glycoprotein in adult rat brain.

Amino Acids↗
PubMed1981

Hemiacidrin irrigations to dissolve stone remnants after nephrolithotomy. Problems with solution flow.

Following surgery for branched renal calculi, hemiacidrin irrigation may be useful to dissolve any residual stones. Struvite, the mineral in these stones, is itself an alkaline buffer and can raise the pH of the irrigating solution rendering it ineffective. Large volumes of hemiacidrin must reach the stone remnants or they are unlikely to dissolve. Two cases are described in which creative positioning of the patient or the irrigation catheters was necessary to permit adequate amounts of hemiacidrin to reach and dissolve stone remnants.

Adult↗
PubMed1980

The role of extra-hepatic tissues in the receptor-mediated plasma clearance of glycoproteins terminated by mannose or N-acetylglucosamine.

The mannose- and N-acetylglucosamine-specific pathway for the clearance of mammalian glycoproteins has been characterized by using 125I-labelled neoglycoproteins, glycosidase-treated orosomucoid and lysosomal glycosidases (beta-glucuronidase and beta-N-acetylglucosaminidase) as probes. There are two components to this pathway in vivo; one liver-dependent and the other extrahepatic or liver-independent. Cells that mediate clearance by the latter component of the pathway are present in spleen, bone and in elements of the reticuloendothelial system, but not in the kidney. Glycoproteins that possess terminal mannose, glucose or N-acetylglucosamine residues, including various lysosomal enzymes, are rapidly cleared from plasma via this pathway. Glucose-terminated glycoproteins are recognized by two pathways in the intact animal; the hepatic galactose-specific pathway and the mannose/N-acetylglycosamine-specific pathway, which is present in liver and in peripheral tissues. Following removal of the liver by surgical evisceration, glucose-terminated glycoproteins are cleared whereas glycoproteins bearing galactose are not cleared. Uptake of 125I-labelled neoglycoproteins and agalacto-orosomucoid by isolated alveolar macrophages closely mimics clearance in vivo by the mannose/N-acetylglucosamine pathway. Neoglycoproteins terminated by mannose, glucose or N-acetylglucosamine all compete with 125I-labelled agalacto-orosomucoid for uptake by receptor-mediated pinocytosis. The extent of substitution of the neoglycoproteins is a critical determinant of their inhibitory potency. It is proposed that mononuclear phagocytes are in important component of the clearance pathway in vivo. The mannose/N-acetylglucosamine pathway may be important in the regulation of extracellular levels of various glycosylated macromolecules, including lysosomal hydrolases.

Abdomen↗
PubMed1980

Receptor-mediated pinocytosis of mannose glycoconjugates by macrophages: characterization and evidence for receptor recycling.

125I-Mannose--BSA is taken up by alveolar macrophages by receptor-mediated endocytosis. Uptake is macrophage-specific and does not occur in polymorphonuclear leukocytes. Binding (4 degrees C) and uptake (37 degrees C) of 125I--Man--BSA are time- and ligand concentration-dependent [Kuptake = 40 nM; Kd (4 degrees C) = 10 nM]. When adjusted for ligand degradation, ligand uptake is linear with time. Binding saturates at 60 min and requires Ca++. Following binding, ligand remains on the cell surface where it can be released by EGTA and trypsin. Internalization of prebound ligand occurs very rapidly (t 1/2 less than 5 min) when cells are warmed to 37 degrees C. Following internalization of prebound ligand, binding activity is rapidly recovered (t 1/2 less than 5 min). Trypsin treatment (4 degrees C) substantially reduces binding activity (greater than 70% per 30 min). However, binding activity is rapidly recovered in cells treated with trypsin at 4 degrees C by warming to 37 degrees C in the absence of added ligand. Trypsin treatment at 37 degrees C rapidly destroys binding and uptake. On the contrary, 4 degrees C trypsin treatment produces only a modest reduction in subsequent ligand uptake. These results, taken together with the observation that cycloheximide has no effect on ligand uptake, suggest that receptors must be spared from degradation and that reutilization of receptors probably occurs.

Animals↗
PubMed1978

Plasma clearance of glycoproteins with terminal mannose and N-acetylglucosamine by liver non-parenchymal cells. Studies with beta-glucuronidase, N-acetyl-beta-D-glucosaminidase, ribonuclease B and agalacto-orosomucoid.

Glycoproteins having mannose and/or N-acetylglucosamine in the terminal non-reducing position [Stockert, Morell & Scheinberg (1976) Biochem. Biophys. Res. Commun. 68, 988--993], and various lysosomal enzymes [Stahl, Schlesinger, Rodman & Doebber (1976) Nature (London) 264, 86--8] are rapidly cleared from plasma by the liver after intravenous administration. A liver cell-separation technique was used to determine the cellular localization of 125I-labelled beta-glucuronidase, ribonuclease B, agalacto-orosomucoid and asialo-orosomucoid. On a specific readioactivity basis, all ligands except 125I-labelled asialo-orosomucoid were enriched in the non-parenchymal cell fraction. Isolated cells, fixed and stained for beta-glucuronidase or N-acetyl-beta-D-glucosaminidase activity after intravenous injection of the enzymes, showed enrichment in the non-parenchymal cell fraction (probably Kupffer cells). After uptake by the non-parenchymal cells, liver lysosomal beta-glucuronidase and N-acetyl-beta-D-glucosaminidase showed degradation half-times of 2.2 and 0.4 days respectively.

Acetylglucosamine↗
PubMed1978

Changes in the kinetics of muscle contraction in vitamin D-depleted rats.

Using an in situ rat soleus neuromuscular preparation, changes in the muscle contraction kinetics in response to vitamine D depletion were studied. For a single isometric contraction, the time-to-peak tension (Tp) and the time-for-recovery-half-way-to-resting tension (T1/2r) were recorded. For a 150 Hz, 300 msec tetanus, the T1/2r was determined. Animals raised on high-calcium, high-phosphate, vitamin D-depleted diets showed prolongation of all parameters. Repletion of vitamin D returned Tp and T1/2r values to normal. Neither dietary calcium deficiency nor thyroparathyroidectomy produced an prolongation of Tp or T1/2r values. Therefore, based upon the experimental data, it appears that vitamin D or one of its metabolites, independent of any effect on the serum calcium or serum phosphate concentration, is necessary for normal muscle relaxation.

Animals↗
PubMed1978

Evidence for receptor-mediated binding of glycoproteins, glycoconjugates, and lysosomal glycosidases by alveolar macrophages.

Alveolar macrophages have been shown to bind glycoproteins and synthetic glycoconjugates (neoglycorpoteins) that have mannose, N-acetylglucosamine, or glucose in the exposed, nonreducing position. Galactose-terminal glycoproteins are not bound. Binding of radiolabeled ligands to cells is nearly completely impaired by the presence of an excess of yeast mannan. Binding is temperature sensitive and proceeds optimally at pH 7.0. Prior treatment of the cells with trypsin severely decreases their capacity to bind ligands. An inhibition assay has been developed, using radioiodinated glucose-albumin conjugate, agalacto-orosomucoid, beta-glucuronidase, and RNase B as ligands. Various glycoproteins have been shown to be effective inhibitors of ligand binding including horseradish peroxidase, agalacto-orosomucoid, beta-glucuronidase, ovalbumin, agalacto-fetuin, and RNase B. RNase A and asialo-fetuin are ineffective as antagonists. The results suggest the presence of a cell surface receptor on alveolar macrophages that binds glycoproteins having terminal sugars with the mannose or glucose configuration.

Animals↗