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R C Wiggins

Publications and source records attributed to R C Wiggins.

At least 91 records · Page 5Linked to original sources
PubMed1986

Amount of antibody is critical for immune complex displacement by charge competition from both rabbit glomeruli and anionic beads.

The purpose of this study was to determine the feasibility of displacing cationized bovine serum albumin (CBSA) immune complexes from glomeruli by charge competition. An in vitro model identified protamine as an effective agent for displacing 125I-CBSA from anionic beads (dextran sulfate-coated Sepharose 4B). Anti-CBSA serum prevented displacement of 125I-CBSA from anionic beads in a dose-dependent fashion. When 125I-CBSA was injected intravenously into rabbits 98% of 125I-CBSA disappeared from blood within 5 min, at which time CBSA was visualized by immunofluorescence in glomerular capillary walls but not in liver, muscle, skin, spleen or lung. By 24 h 90% of 125I-CBSA had disappeared from glomeruli. In contrast, injection of anti-CBSA antibody caused persistence of 125I-CBSA in kidney (particularly along glomerular capillary walls) for more than 7 days (detected by counting 125I in kidney, by radionuclide imaging and by immunofluorescence). Protamine administration (50 mg intravenously daily for 6 days) caused significant reduction of 125I-CBSA trapped in kidney only if the amount of anti-CBSA injected was small. Protamine did not significantly displace 125I-CBSA from glomeruli if the anti-CBSA dose was larger. Therefore both in vivo and in vitro displacement of 125I-CBSA by protamine depended upon the amount of antibody. We conclude that although charge dependent displacement of immune complexes from glomeruli is probably feasible using protamine this approach would only work in the presence of small amounts of antibody.

Animals↗
PubMed1985

Fragmentation and polymeric complexes of albumin in human urine.

Analysis of urine proteins of some individuals with proteinuria by SDS-PAGE and silver staining revealed protein bands in urine which did not appear to be present in plasma. The bands migrated with apparent molecular weights of 260 000, 180 000, 110 000, 45 000, 40 000, 30 000, 24 000, 18 000 and 11 000. These bands were shown to be albumin polymer and fragments by using a polyclonal antibody to (a) immunoprecipitate radiolabelled urine proteins, and (b) identify bands blotted from SDS-PAGE gels onto nitrocellulose paper. The specificity of the polyclonal anti-albumin antibody was confirmed by using two mouse monoclonal antibodies raised against human albumin which, between them, recognized the same protein bands on nitrocellulose paper as did the polyclonal antibody. The results of these studies of albumin in human urine confirm that albumin exists as polymer and also show that albumin fragmentation occurs in urine. Fragmentation occurs by proteolysis of the albumin molecule both at sites within and outside disulfide loops. The predominant cleavage site appears to be approximately two-fifths of the distance from one end of the albumin molecule to produce disulfide-linked fragments of about 45 000 and 30 000 molecular weight.

Albuminuria↗
PubMed1985

The corpus callosum during postnatal undernourishment and recovery: a morphometric analysis of myelin and axon relationships.

This study was designed to compare morphometric relationships between myelin lamellae and axons in undernourished and well nourished developing rats, and in rats nutritionally rehabilitated for two weeks. Although sampling techniques employed in this study were not specifically designed to compare numbers of myelinated fibers in test and control populations, we did observe a trend indicating a reduction in the numbers of myelinated fibers. The mean numbers of myelin lamellae, from an average of all myelinated axons, were not different in control and test population. However, regression analysis of axon sizes by numbers of myelin lamellae revealed significant differences from the normal in 21-day-old undernourished rats. For callosal axons of any size, there were too few myelin lamellae in the undernourished rats. A partial recovery was observed in relatively small fibers by 35 days of age, but no recovery was observed in larger sized fibers. Comparison of the frequency distribution of axon circumferences of myelinated fibers revealed an increase in average axonal caliber. Computation shows that although mean numbers of lamellae were not altered by undernourishment, the axons themselves are increased in size by about 10%. This unexpected result indicates that the relationship normally governing the numbers of myelin lamellae is altered by postnatal nutritional deprivation, and that the relatively larger axon calibers do not produce in the ensheathing oligodendroglia any compensatory increase in the layers of myelin.

Animals↗
PubMed1985

Prolonged daily inhalation of halothane modifies the dose-response pattern to acute administration of halothane. An electrophysiological study.

Sensory-evoked field potentials were obtained from freely moving rats implanted sterotaxically with permanent electrodes in the parafasciculus thalami (PF), mesencephalic central gray (CG), ventromedial hypothalamus (VMH) and somatosensory cortex (SCX). Animals were exposed to chronic, subanesthetic inhalation of halothane (0.5%, 3 hr/day, 5 days/week) for 56 days. The averaged acoustic evoked responses (AAER) were recorded on day 0, as well as at 28 and 56 days after a 48-hr halothane-free period ("control") and after acute doses of halothane (0.25, 0.5 and 1.5%). In general, the averaged sensory-evoked responses from each structure were affected at day 0 of the experiment in dose-response manner, and suppression of the responses was the main effect of halothane. Chronic exposure to subanesthetic inhalation of halothane produced marked alteration of the "control" recording from 3 CNS structures; mainly from the mesencephalic central gray, the parafasciculus thalami and the somatosensory cortex and the direction (increase or decrease) of the averaged acoustic evoked responses in all the four CNS sites studied. The total responsiveness was modified as well, i.e. the recordings obtained from the mesencephalic central gray and somatosensory cortex exhibited hypersensitivity while the recordings obtained from the parafasciculus thalami and ventromedial hypothalamus exhibited tolerance. It is concluded that prolonged and intermittent inhalation of halothane can alter the electrophysiological properties of the four structures investigated.

Acoustic Stimulation↗
PubMed1985

Role of oxygen radicals in phorbol myristate acetate-induced glomerular injury.

Phorbol myristate acetate (PMA) is known to be a potent activator of neutrophils and macrophages resulting in the generation of large amounts of oxygen-free radicals by these cells. When injected into the left renal artery of 250 to 300 g male Sprague-Dawley rats, PMA caused significant proteinuria compared to control rats which received normal saline (35.4 +/- 4 mg/24 hr in PMA treated vs. 14.1 +/- 0.9 mg/24 hr in saline control, P less than 0.02). The proteinuria was associated with evidence of glomerular injury. These PMA-induced alterations were not prevented by complement depletion but were prevented by prior depletion of neutrophils. The coinstillation of catalase prevented the development of the proteinuria (catalase + PMA 12.7 +/- 2.3 mg/24 hr vs. PMA alone 38.2 +/- 5.7 mg/24 hr, P less than 0.001) suggesting that H2O2 and/or its metabolites derived from neutrophils were important in the PMA-induced proteinuria. In contrast, superoxide dismutase (SOD) had no effect. We conclude that, following the intra-arterial injection of PMA, neutrophil-derived hydrogen peroxide and/or its metabolic products are capable of causing acute proteinuria in association with morphological alterations in glomeruli of rats.

Animals↗
PubMed1985

Effect of reactive oxygen species on myelin membrane proteins.

Fresh myelin, isolated from brainstems of adult rats, was incubated in the presence of Cu2+ and H2O2. Electrophoretic analysis of the reisolated myelin membrane revealed a gradual loss of the protein moiety from the characteristic pattern and an increase in aggregated material appearing at the origin of the gel. The aggregation of proteins was time-dependent and was concomitant with the accumulation of lipid peroxidation products reactive with thiobarbituric acid. Furthermore, during the course of incubation, there was a gradual decrease in the amount of recovered light myelin and a quantitatively similar increase in heavier myelin subfractions. The aggregation of proteins seems not to be directly related to the buoyant densities of myelin fragments. The peroxidative damage to the myelin proteins may be an important contributor to pathochemistry of myelin sheath, in particular, and in general it implies the susceptibility of the protein moiety of cell membranes to oxygen-induced deterioration.

Animals↗
PubMed1985

Intracellular translocation of myelin proteolipid protein.

Brainstem slices prepared from 22-day-old rats were employed to study the intracellular translocation of radioactively labeled myelin proteolipid protein (PLP). Double-isotope and short pulse-chase procedures allowed us to demonstrate the flux of PLP through nine different subcellular membrane fractions that were isolated on the basis of their particle size and buoyant density. Tagged PLP was rapidly depleted from microsomes, showed transient passage through a number of presumably intermediate membranous pools, and accumulated in myelin. On the basis of the kinetics of PLP labeling and isotope ratios, the membranes can be arranged as they participate in the intracellular translocation of PLP and consistently show a pattern indicating possible precursor-product relationships.

Animals↗
PubMed1985

Acute hypotension due to platelet serotonin-induced chemoreflexes after intravenous injection of dextran sulfate in the rabbit.

The hypotension and bradycardia observed after intravenous injection of dextran sulfate in rabbits was prevented by prior depletion of circulating platelets, but was not prevented by depletion of the third component of complement or Hageman factor. Dextran sulfate injection caused immediate thrombocytopenia with temporary localization of platelets within lungs. Morphological analysis revealed platelet aggregates in lung capillaries. The platelets had changed shape and were in the process of degranulating. Serotonin and histamine levels in blood increased approximately 5-fold and 7-fold, respectively, after dextran sulfate injection. The cardiovascular events following dextran sulfate injection were mimicked by intravenous serotonin but not by intravenous histamine injection, although a combination of serotonin and histamine reproduced the pattern of blood pressure changes better than did either agent alone. Quantification of platelets trapped in lung revealed that the potential release of serotonin from trapped platelets could account for the rise in plasma serotonin concentration and the hemodynamic changes observed. Both the dextran sulfate-induced cardiovascular effects and serotonin-induced hypotension were markedly diminished by cutting vagus and depressor nerves, and were virtually abolished by carotid ligation in addition to nerve section. These results support the concept that platelet activation within rabbit lungs may cause hypotension via serotonin-induced chemoreflexes.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

Hageman factor in experimental nephrotoxic nephritis in the rabbit.

This study was performed to investigate whether the Hageman factor (HF) system might contribute to glomerular damage in vivo. HF was purified from rabbit plasma. The proteolytic activation pattern of 80,000-dalton rabbit HF was the same as that previously reported for human HF. Anti-HF IgG, raised in a goat, was monospecific as judged by immunodiffusion analysis and inhibited HF activity in rabbit plasma. A telescoped model of nephrotoxic nephritis in the rabbit was developed using guinea pig antirabbit glomerular basement membrane IgG injected into rabbits preimmunized against guinea pig IgG. In this model protein excretion was increased by days 3 to 4 in association with glomerular influx of acute inflammatory cells. By days 5 and 6 fibrin was present within glomerular capillaries, beneath endothelial cells, in Bowman's space, and in proximal tubules. By fluorescent microscopic analysis rabbit IgG and C3 had accumulated along the glomerular capillary wall; however, no HF was detectable in glomerular capillary wall over the initial 10 days of glomerular injury. Positive fluorescence for HF was seen within Bowman's space and in tubules along with albumin and plasmin- and fibrin-related antigens. Although the circulating antigenic HF concentration did not change during the glomerular injury, the rate of turnover of 125I-HF did increase. However, when this was factored for turnover of 131I-albumin in a paired study, the relative turnover of 131I-albumin was found to be faster than that of 125I-HF. Proteolysis of 125I-HF in plasma consistent with HF activation was noted in only one of these rabbits in spite of a decrease in antigenic C3 level to 54% of baseline. The 125I-HF appearing in urine of nephritic rabbits had undergone proteolysis from the native 80,000-dalton parent molecule to form fragments of 50,000 and 30,000 daltons, compatible with HF activation. Urine from nephritic rabbits also contained procoagulant activity that was HF dependent. These results are compatible with the concept that HF passively crosses the damaged glomerular filter where it may become activated in Bowman's space or in fluid draining damaged glomeruli in this model of nephrotoxic nephritis in the rabbit.

Animals↗
PubMed1985

Procoagulant activity in glomeruli and urine of rabbits with nephrotoxic nephritis.

A telescoped model of nephrotoxic nephritis in the rabbit, using guinea pig antiglomerular basement membrane IgG in rabbits preimmunized with guinea pig IgG, reproducibly induced crescentic nephritis. Procoagulant activity (PCA) was measured in sieve-isolated glomeruli that had been either sonicated or cultured for 48 hours. In both sonicated and cultured glomeruli PCA peaked on days 5 and 6. The time course for appearance of PCA corresponded precisely with the appearance of proteinaceous material containing fibrin in Bowman's space as measured by a light microscopic histologic scoring system and confirmed by immunofluorescence and electron microscopy. Glomerular PCA returned to baseline by days 9 and 10 in spite of progression of glomerular injury. PCA also appeared in urine. Urine PCA peaked on day 8 and persisted through day 12 when glomerular PCA had returned to baseline. Glomerular and urine PCA were characterized using human coagulation factor-deficient plasmas and antithromboplastin IgG. Both glomerular PCA and urine PCA were inhibited by antithromboplastin IgG, showing that thromboplastin (tissue factor) contributed to PCA. The PCA in glomerular sonicates was dependent on factor X, but independent of factor VII or Hageman factor, suggesting that factor VII was present. Following glomerular culture for 48 hours the PCA had changed and in some cases was dependent on Hageman factor, factor IX, and factor VII for full PCA expression. Urine PCA was uniformly Hageman factor dependent and sometimes independent of factors VII and X. No active thrombin was present. The forms of glomerular and urine PCA were, therefore, complex. They seemed to be primarily driven by thromboplastin but also appeared to require the presence of the intrinsic coagulation pathway for full expression of PCA.

Animals↗
PubMed1984

Polymeric complexes and fragments of albumin in normal human plasma.

Nitrocellulose blots of normal human plasma proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were examined for polymeric complexes and fragments of albumin using an immunoperoxidase-labelled mouse monoclonal anti-human albumin antibody. Under reducing conditions, no polymeric complexes were seen. Under non-reducing conditions, polymeric complexes were detected at the following molecular weights: 210 000, 168 000, 147 000, 132 000, and 110 000. These probably represent both homo- and heteropolymers of albumin. Fresh plasma samples were also analyzed by S-200 chromatography with the same results indicating that detection of polymeric complexes was not an artifact of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. In quantitative terms, polymeric complexes constituted 0.3-2.8% of the total albumin present. Fragments of albumin were also seen in normal human plasma with molecular weights of 45 000, 28 000 and 19 000. These fragments probably represent breakdown products of albumin in normal blood, and they constituted less than 2% of the total albumin present.

Antibodies, Monoclonal↗
PubMed1984

Undernutrition and the development of brain neurotransmitter systems.

While there are homeostatic mechanisms to protect the brain against wide fluctuations in the availability of essential nutrients, food deprivation is known to influence brain neurochemistry. Given the growing problem of infant undernutrition and the fact that the developing nervous system appears to be especially vulnerable to this type of insult, numerous studies have been conducted to define the relationship between nutritional factors and cellular growth and maturation in the brain. The data suggest that the development of both neural and nonneural elements are significantly affected by undernutrition. This includes processes and substances important for neurotransmission such as transmitter synthesis, degradation and receptor sites. Because many neuropsychiatric conditions can be traced to dysfunctions in synaptic neurochemistry, it is possible that some of the central nervous system abnormalities which result from childhood undernutrition may be a consequence of a modification in synaptic biochemistry. The present report reviews data relating to this issue with the aim of assessing its relevance to developmental neurobiology.

Acetylcholine↗
PubMed1984

Brain myelination in the offspring of ethanol-treated rats: in utero versus lactational exposure by crossfostering offspring of control, pairfed and ethanol treated dams.

Pregnant Long-Evans rats were received on day 5 of gestation and divided into 4 treatment groups: (1) 27% calories provided as ethanol in a liquid diet; (2) pairfed i.e., isocaloric liquid diet restricted to match group (1); (3) liquid diet provided ad libitum; and (4) laboratory chow and water provided ad libitum. Litters were culled to 8 pups at birth and crossfostered across dams in all 4 groups to provide offspring falling into 16 different experimental groups, including some exposed to ethanol in utero only and some exposed only during lactation. At birth, blood alcohol levels of dams, culled pups and alcohol levels in the stomach contents of culled pups were measured. All pups were weaned and fed laboratory chow and water ad libitum from 21 days onward. At ages 16, 21, 30 and 52 days, pups were sacrificed, and organ/body weight ratios and brain myelin concentrations were determined. Ethanol treated dams had longer gestational periods. The offspring of ethanol treated dams which were crossfostered to pairfed and well nourished dams during lactation had delayed eye opening, persistent lag in body growth and slightly lower brain myelin concentrations. Offspring of dams which were either pairfed or well nourished during gestation, but crossfostered during lactation to ethanol treated dams, had abnormal organ weights, abnormal brain weights and severely depressed brain myelin concentrations persisting through 52 days of age. Thus, lactational ethanol effects on brain myelin were more severe than gestational effects; body growth was affected more severely by gestational exposure, and gestational effects were generally less severe with adequate nutrition.

Alcoholism↗
PubMed1984

Myelination of the rat optic nerve during postnatal undernourishment and recovery: a morphometric analysis.

Newborn rats were undernourished from the second postnatal day through 20 days of age and weaned to a diet of laboratory chow ad libitum. Optic nerve development was examined by various light and electron microscopic techniques at 14, 21, 35 and 63 days of age. The degree of undernourishment achieved resulted in body growth lag comparable to results obtained in our previous studies. Although cellularity (cells per photomicrograph area) of the oligodendroglia was unaffected, there was an apparent significant relative reduction in the total number of myelinated fibers by 21 days of age, as determined by light microscopic sampling. Ratios of unmyelinated-to-myelinated fibers were thus estimated by electron microscopy, and results indicated an early increase in the ratio (14 days). Either as the result of catch up in a developmental lag, or as a result of possible restorative effects of rehabilitation, these differences were significant by 35 days of age. The relationship between axon circumference and numbers of myelin lamellae was determined by regression analysis, which revealed a significant reduction in numbers of lamellae over axons of all sizes at 14 days. By 21 days, only fibers in the size range of 1-2 micron of circumference showed a difference, and by 35 days there were no significant differences. These results all indicate that there is a significant myelin reduction in optic nerve of the undernourished rat.

Aging↗
PubMed1984

The relationship between nutritional adequacy and brain myelin accumulation: a comparison of varying degrees of well fed and undernourished rats.

Rats undernourished through 17 days of age to produce mild weight lag (less than 20%) had either the same amount, or slightly more myelin than well fed controls. Schedules of undernourishment producing approximately 30, 40 and 50% body weight lags produced corresponding rank-ordered myelin deficits of 25, 55 and 60%, respectively. Brain growth was relatively spared in all cases, never exceeding a deficit of 10%. Absolute myelin deficits did not recover following nutritional rehabilitation, although myelin continued to increase in both normal and all test populations.

Animals↗
PubMed1984

Brain hypomyelination during postnatal undernourishment: a comparison of proteolipid protein synthesis versus assembly into membrane.

A double isotope methodology which permits the separate analysis of (i) the synthesis of myelin proteolipid protein and (ii) its subsequent assembly into myelin membrane was applied to the case of postnatal undernourishment of rats. Results showed that brain proteolipid protein synthesis was greatly depressed, indicating that undernourishment limited the production of myelin components. This is a different result from that obtained in the mouse Quaking mutant, in which case component formation is normal whereas their assembly into myelin membrane is blocked. The results have possible implications regarding cellular development of oligodendroglia of undernourished rats.

Animals↗
PubMed1984

Evidence for the role of oxygen radicals in acute nephrotoxic nephritis.

Acute glomerular injury in the rat has been induced by the intrarenal, intraarterial infusion of sheep antibody to glomerular basement membrane (antiglomerular basement membrane). The antiglomerular basement membrane antibody has been verified to be of the variety that is complement and neutrophil dependent for the induction of acute proteinuria, which peaks during the first 24 hours. Following injection of the antibody, acute, intense, glomerular injury resulted, with the denuding of glomerular vascular basement membrane associated with extensive damage or destruction of glomerular endothelial cells and fusion of epithelial cell foot processes. Treatment of animals with catalase produced, in a dose-dependent manner, as much as 75% protection against glomerular injury, as assessed by reduction in the proteinuria. Treatment of animals with superoxide dismutase caused a small reduction in the degree of glomerular injury, again assessed by a reduction in proteinuria. However, this protective effect of superoxide dismutase was not found to be statistically significant. The hydroxyl radical scavenger, dimethyl sulfoxide, which has been shown to protect against endothelial cell injury following systemic activation of complement, was not protective in the anti-GBM model. Morphologically, glomeruli from catalase-protected rats showed numerous neutrophils but little or no evidence of injury of either glomerular endothelial or epithelial cells. These data suggest that acute glomerular injury produced by antiglomerular basement membrane is related to H2O2 production from activated neutrophils.

Acute Disease↗