Biomedical subjects

J C Garancis

Publications and source records attributed to J C Garancis.

At least 19 recordsLinked to original sources

PubMed1992

Mast cells and calcium in severe uremic itching.

Mast cells may be more abundant in the tissues of uremic patients and may contribute to itching via mediator release. Because mast cell (MC) granule release may be inhibited by ultraviolet B (UVB) radiation, we investigated skin MC in the superficial dermis by quantitative histomorphometry before and after whole body UVB for uremic itching. Toluidine blue-stained 3.5 mm punch biopsy specimens were examined with a micrometer grid after separate coding. Upon entry to the study, itching dialysis patients indicated their itching intensity on a visual analog scale (0 to 10). Concurrent study of living, related kidney donors (controls, n = 11) and their recipients (n = 11) showed no differences in MC number per unit area. Compared to controls, skin MC number was not greater in itching dialysis patients (n = 20). MC number decreased after 2 months of UVB from 1.6 +/- 0.6 (standard deviation) to 1.0 +/- 0.7 (n = 11, p = 0.025). Pre-UVB total plasma calcium correlated directly with itching intensity, but not with MC number. Plasma phosphate and intact parathyrin level were not statistically related to itching or MC number. Of the 14 subjects that completed UVB, 8 had objective benefit, and mean itching intensity declined from 7.1/10 to 5.2/10 in the 14 subjects. The conclusion is that although skin MC number may decline with chronic UVB, MC number is not related to uremic itching, and hypercalcemia, but not elevation of parathyrin or plasma phosphate, relates statistically to severe uremic itching.

Adult↗

PubMed1991

Histopathologic changes in snoring and obstructive sleep apnea syndrome.

The pathophysiologic events that lead to the loss of airway compensation in obstructive sleep apnea (OSA) are poorly understood. The development of airway instability may be secondary to changes in neurologic control, airway morphology, or both. To identify potential histopathologic features of pharyngeal tissues that may contribute to OSA, transverse sections of the distal soft palate and uvula were qualitatively compared using light and electron microscopy from 4 severe apneics (greater than 50 apnea/hour), 4 severe snorers (less than 20 apnea/hour), and 4 nonsnorers. Light microscopy of both apneics and snorers revealed mucous gland hypertrophy with ductal dilation and focal squamous metaplasia, disruption of muscle bundles by infiltrating mucous glands, focal atrophy of muscle fibers, and extensive edema of the lamina propria with vascular dilation. Severe snorers did not differ qualitatively from apneics in the characteristic changes found; however, some snorers had less extensive changes. No distinctive histopathologic findings could be associated with the development of apnea. Electron microscopy of severe apneics identified frequent focal degeneration of myelinated nerve fibers and axons. The finding of similar histopathologic changes in apneics and severe snorers supports previous speculation of a common etiology not directly related to apnea, such as vibratory trauma to pharyngeal tissues. Degenerative changes in peripheral nerves, identified on electron microscopy, however, may contribute to airway instability and the development of obstructive apnea by impairing pharyngeal reflexes.

Atrophy↗

PubMed1990

Antigenic and catalytic disparity in the distribution of cytochrome P-450-dependent 25-hydroxyvitamin D3-1 alpha- and 24-hydroxylases.

Chick 25-hydroxyvitamin D3-1 alpha-hydroxylase, a cytochrome P-450 monooxygenase with a molecular weight of 57 kDa, can be isolated as described by Mandel et al. (1990 b). Under normal physiological circumstances, it occurs exclusively in kidney mitochondria. An isozyme of the 1 alpha-hydroxylase, known as the 24-hydroxylase, which uses the same substrate to yield an isomeric product, is also a cytochrome P-450 monooxygenase, has a molecular weight of 55 kDa, and like-wise occurs in kidney mitochondria. The amino-terminal sequences of the first 10 residues of the two isozymes are 100% homologous. Monoclonal antibodies of the IgM class raised against the 1 alpha-hydroxylase, which quantitatively discriminate against other P-450 cytochromes of mitochondrial or microsomal origin, recognize and interact with the 24-hydroxylase as an antigen. In the present study we show that the intestine, which is the only non-renal tissue with demonstrable 24-hydroxylase activity, gives a positive peroxidase-antiperoxidase immunohistochemical reaction using the monoclonal antibodies against the 1 alpha-hydroxylase. The reactions revealed that the antigen in the kidney is restricted to the cortical proximal tubular cells while in the intestine, the antigen is localized in the enterocytes of the villi. In kidney medullary or intestinal crypt cells, or in liver, heart and lung tissues where 1 alpha-hydroxylase or 24-hydroxylase activity could not be detected using cell or tissue homogenates, the immunohistochemical reactions were also negative.(ABSTRACT TRUNCATED AT 250 WORDS)

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed1990

Chemical degeneration of intestinal nerves.

In 15 dogs, cobalt chloride solutions were infused close intra-arterially to perfuse a short segment of the jejunum. In an additional four dogs, the jejunum was perfused with the aqueous vehicle (perfusion control). All animals were killed after 1 mo and tissue samples from cobalt-treated and from nonperfused intestine (tissue comparison control) were obtained for electron microscopic and immunohistochemical studies. Segments infused with 0.25 g/dl cobalt solution showed minimal changes; the most striking feature was an increase of vasoactive intestinal polypeptide (VIP)- and substance P-containing neurosecretory granules. Cobalt chloride at higher concentrations (0.75-1.5 g/dl) induced degeneration of ganglion cells and axons in both the myenteric and submucosal plexi. In contrast, the smooth muscle and the mucosal cells of the cobalt-perfused intestine showed no histological abnormalities. Immunohistochemical staining of tissues treated with 0.75-1.5 g/dl cobalt solutions revealed absence of substance P, Met-enkephalin, and VIP immunoreactivity in all section studied; control segments showed the presence of all three peptides. Cobalt chloride in concentrations of 0.75-1.5 g/dl causes degeneration of intestinal intramural nerves and provides an experimental model suitable for studying the role of these nerves in small intestinal function.

Animals↗

PubMed1990

Effects of enteric neural defunctioning on small bowel motility.

In this study, we investigated the role of intrinsic nerves of the small intestine on phase III migration of the migrating myoelectric complex. Fasting myoelectric activity was recorded from the small bowel in chronically instrumented dogs. Once control experiments were completed, the animals were divided into two groups and were reoperated. In the first group of five dogs, a 1.5-g/dl aqueous solution of cobaltous chloride (shown to induce degeneration of intestinal intrinsic nerves) was infused close intra-arterially to perfuse a 15-cm segment of jejunum. In the second group of dogs, a catheter was implanted in a branch of the superior mesenteric artery supplying a 15-cm segment of intestine. Tetrodotoxin (0.3-1 micrograms/kg) was infused through the catheter just before the arrival of phase III activity in the perfused segment. Subsequent to the fifth postcobalt perfusion day, phase III traversed but did not occur in the cobalt-treated segment. When tetrodotoxin was injected through the catheter, spontaneous phasic myoelectric and contractile activities in the perfused jejunal segment were inhibited, but phase III migration was not blocked. These findings suggest 1) acute or chronic defunctioning of enteric nerves does not interrupt phase III migration, but 2) phase III expression is dependent on the integrity of intrinsic nerves.

Animals↗

PubMed1990

Alteration of endothelium-dependent distribution of myocardial blood flow after coronary occlusion and reperfusion.

We have previously demonstrated that intracoronary infusion of the endothelium-dependent vasodilators acetylcholine, ATP, or arachidonic acid produces a preferential increase in subendocardial blood flow in anesthetized dogs. This study was performed to assess the effects of coronary artery occlusion and reperfusion on the distribution of myocardial blood flow produced by endothelium-dependent and endothelium-independent vasodilators. The endothelium was damaged by occlusion of the left anterior descending coronary artery for 45 minutes followed by 60 minutes of reperfusion in pentobarbital-anesthetized dogs. Intracoronary infusions of the endothelium-dependent vasodilators acetylcholine, bradykinin and thiazolylethylamine or the endothelium-independent vasodilator sodium nitroprusside were performed, and regional myocardial blood flow (by radioactive microspheres) was measured before and after occlusion and reperfusion. There were no changes in systemic hemodynamics during intracoronary infusion of vasodilators before or after coronary occlusion and reperfusion. All vasodilators produced similar increases in transmural blood flow before occlusion; however, only the endothelium-dependent vasodilators produced a significant increase in the subendocardial-to-subepicardial blood flow ratio. Increases in transmural flow as well as the preferential increase in subendocardial blood flow produced by acetylcholine, bradykinin, and thiazolylethylamine were attenuated after coronary occlusion and reperfusion. In contrast, increases in transmural blood flow produced by sodium nitroprusside were unchanged. These results suggest that the preferential increase in subendocardial perfusion produced by acetylcholine, bradykinin, and thiazolylethylamine is endothelium-dependent and may be selectively modified by ischemic insult.

Acetylcholine↗

PubMed1990

Monoclonal antibodies to chick renal calcium regulating hemeproteins. Biochemical and immunohistochemical interactions with mitochondrial 25-hydroxyvitamin D3 hydroxylases.

The kidney mitochondrial monooxygenases known as 25-hydroxyvitamin D3 1 alpha- and 24R-hydroxylases are two analogous enzymes which utilize the vitamin as a common substrate for the catalytic production of 1 alpha,25-dihydroxyvitamin D3 and 24R,25-dihydroxyvitamin D3. These two enzymes are complexes of NADPH-ferredoxin reductase, and an (Fe-S)-cluster containing ferredoxin with a redox potential that allows the ultimate transfer of reducing equivalents to the terminal oxidases distinctly known as cytochromes P-450(1) alpha and P-450(24). We have used in vitro immunizations of splenocytes obtained from mice sensitized with the purified cytochrome P-450(1) alpha to generate three hybridoma clones from fusion with p3 x 63.Ag8.653 myeloma ATCC cells which selectively secrete monoclonal antibodies (MAbs) of the IgM class. The MAbs have been partially purified by ammonium sulfate fractionation followed by size separation chromatography on Sephacryl S-200-HR. We have compared the structural similarities and differences between the two kidney enzymes in Western Blot analyses using horseradish peroxidase conjugated goat anti-mouse Igs specific for the heavy and light chains of mouse IgA, IgG and IgM. The MAbs from all three clones recognized and interacted with apparent common epitopes of the two hydroxylases but selectively discriminated against liver microsomal P-450LM2 type and adrenal mitochondrial P-450SCC cytochromes. The cytochromes P-450(1) alpha and P-450(24) were detected as two separate bands with approximate molecular weights of 57 and 55 KDa, respectively. In reconstitution of hydroxylase activities in vitro, the MAbs were equally effective in inhibiting the 1 alpha-hydroxylation and 24R-hydroxylation reactions. The ratio of micrograms of Igs to pmol cytochrome P-450 for a 50% inhibition of either activity was approximately 25. These results, collectively, seem to suggest the existence of a precursor-product relationship between the kidney mitochondrial 1 alpha- and the 24R-hydroxylases, or perhaps, a common ancestral origin. Immunochemical peroxidase anti-peroxidase staining of kidney tissue first exposed to the MAbs revealed that only the proximal tubular segment of the nephron was specifically enriched with the cytochromes.

Adrenal Glands↗

PubMed1989

Clinical heterogeneity and treatment response in inclusion body myositis.

Inclusion body myositis has been described as an inflammatory myopathy with distinctive clinical and pathologic features that is refractory to treatment. Ten cases of inclusion body myositis, as defined by histopathologic findings, were reviewed to determine whether the clinical characteristics are different in patients whose disease has been defined by light and electron microscopic studies compared with those whose disease has been defined by light microscopic studies alone. The clinical characteristics of both groups of patients were similar, and 2 patients have had excellent responses to treatment. Although inclusion body myositis represents a histologic subset of polymyositis, from a clinical perspective, it must be considered a nonspecific designation. Despite a generally poor prognosis, therapeutic intervention is still warranted.

Adult↗

PubMed1989

Acquired progressive kinking of the hair.

A 14-year-old girl had acquired progressive kinking of the hair. Light microscopy disclosed flattening of the hair shafts with partial twists at irregular intervals. Cross-sections of paraffin-embedded hairs were elliptic or irregular in configuration. Scanning electron microscopy confirmed the presence of partial twists and demonstrated canalicular grooves that extended for variable lengths along the hair shafts. Acquired progressive kinking of the hair most resembles woolly hair in appearance and structural abnormalities.

Adolescent↗

PubMed1987

Evidence that stimulation of 1,25(OH)2D3 production in primary cultures of mouse kidney cells by cyclic AMP requires new protein synthesis.

When primary culture of C75BL6 mouse cortical kidney cells in serum-free medium were incubated with unlabeled 25(OH)D3, they produced a metabolite which co-migrated with authentic 1,25(OH)2D3 and which could be measured by competitive receptor assay. A metabolite co-migrating with authentic 10-oxo-19-nor-25-OH-D3 was also produced. However, when cultures were incubated with 25(OH)D3 for 1 hour or longer, 10-oxo-19-nor-25-OH-D accounted for less than 15% of the total 3H-1,25(OH)2D3 displacement activity. Production of 1,25(OH)2D3 increased with increasing content of the culture, with time of incubation, and with substrate concentration. The apparent Km was 1.4 +/- 0.6 microM and Vmax 2.6 +/- 0.4 pM/mg protein/hr. These cultures possessed a very high level of phosphodiesterase activity, as indicated by their high cyclic AMP (cAMP) response to IBMX. This high phosphodiesterase activity may have been responsible for the lack of stimulation of 1,25(OH)2D3 production by physiologic or near physiologic concentrations of parathyroid hormone (PTH) in the absence of IBMX. However, when IBMX 10(-6) M was present, bPTH 10(-9) M significantly increased production of both cAMP and 1,25(OH)2D3. There was a close correlation between 1,25(OH)2D3 production and cAMP content of the cultures (basal or stimulated). An incubation time of at least 4 hours was required for cAMP to increase 1,25(OH)2D3 production and was inhibited in the presence of cycloheximide and actinomycin D. This study further documents the regulation of renal 1,25(OH)2D3 synthesis by PTH in mammalian kidney and provides evidence for cAMP as a possibly important second messenger in this effect.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗

PubMed1987

Calcium oxalate crystal interaction with rat renal inner papillary collecting tubule cells.

Rat renal inner papillary collecting tubule cells (RPCT) have been isolated and maintained in primary culture. The cells have been found to be of only one type and they have maintained the characteristics of RPCT cells. The RPCT cells in culture appear as a monolayer with intermittent clumps of rounded cells. When small calcium oxalate monohydrate crystals (COM) or calcium oxalate dihydrate crystals (COD) are added to the monolayer of RPCT cells, the crystals bind on or about these clumps of rounded-up cells. The use of this system as a model for the study of crystal membrane interactions in crystalluria and urolithiasis is discussed.

Animals↗

PubMed1987

Regulation of pH in rat papillary tubule cells in primary culture.

To investigate the mechanisms responsible for urinary acidification in the terminal nephron, primary cultures of cells isolated from the renal papilla were grown as monolayers in a defined medium. Morphologically, cultured cells were epithelial in type, and similar to collecting duct principal cells. Cell pH measured fluorometrically in monolayers grown on glass slides showed recovery from acid loads in Na+-free media. Recovery was inhibited by cyanide, oligomycin A, and N-ethylmaleimide. Cyanide and oligomycin inhibited recovery less in the presence than in the absence of glucose. When cells were first acid loaded in a Na+-free medium and then exposed to external Na+, pH recovery also took place. This recovery exhibited first-order dependence on Na+ concentration and was inhibited by 5-(N-ethyl-N-isopropyl)amiloride. These studies demonstrate that in culture, collecting duct principal cells possess at least two mechanisms for acid extrusion: a proton ATP-ase and an Na+-H+ exchanger. The former may be responsible for some component of the urinary acidification observed in the papillary collecting duct in vivo; the role of the latter in acid-base transport remains uncertain.

Acid-Base Equilibrium↗

PubMed1985

Successful second kidney transplantation in a patient with focal glomerulosclerosis. A case report.

We report a woman who developed renal failure due to focal glomerulosclerosis (FGS). This disease recurred immediately in a kidney transplant from her brother resulting in removal of that graft. She subsequently received a cadaver kidney transplant, and FGS has not recurred after 24 months. This is the first report of nonrecurrence in a second kidney graft, when the first was lost due to recurrent FGS. Whether timing or tissue typing of the second graft in relationship to the first is important is not known. Recurrence of FGS in a first kidney graft should not, however, preclude future transplantation.

Adult↗

PubMed1985

Specificity and duration of post-inflammatory suppression in rabbit lungs challenged with aerosolized antigen.

Rabbits immunized and aerosolized with soluble protein antigens develop a short lived pulmonary inflammation. This is followed by a period of non-specific unresponsiveness which lasts approximately 30 weeks after the first exposure to aerosol treatment. This period is characterized by the inability of the rabbit to exhibit another inflammatory reaction either to the same antigen used to induce the first inflammation, or to a new antigenically unrelated antigen. After 30 weeks however, the animals become responsive (develop another pulmonary inflammation) to a second unrelated antigen, but remain unresponsive to the antigen used to elicit the initial inflammatory response. These studies indicate that following challenge with inhaled antigen, rabbits develop a non-specific suppression of pulmonary inflammation which lasts a finite period of time. When this disappears, the animal is left with an antigen specific suppression of pulmonary inflammation. These studies suggest a model for normal individuals who may respond similarly to potentially harmful inhaled allergens. Individuals with hypersensitivity pneumonitis, however, may not develop antigen specific unresponsiveness. The nature of this unresponsiveness is unknown at present, nor is it known when it begins to develop.

Aerosols↗

PubMed1984

Histopathological and ultrastructural studies of synovium in Milwaukee shoulder syndrome--a basic calcium phosphate crystal arthropathy.

Light and electron microscopic study of synovial specimens from four patients with the Milwaukee shoulder syndrome disclosed vascular congestion, villous and focal synovial lining cell hyperplasia, occasional giant cells, and fibrin deposition both within and on the surface of the synovium. Although these changes are non-specific, the finding of basic calcium phosphate crystal aggregates in all four cases and the near total absence of an inflammatory reaction are helpful in distinguishing this condition from other types of arthritis. The focal areas of synovial cell hyperplasia may relate to the powerful mitogenic effect of both synthetic and naturally occurring calcium-containing crystals in concentrations found in the synovial fluid of these patients.

Aged↗

PubMed1983

Changes in 25-hydroxyvitamin D3 alpha- and 24-hydroxylase activities of kidney cells isolated from rats with either unilateral kidney damage or acute renal insufficiency.

25-Hydroxyvitamin D3 1 alpha- and 24-hydroxylase, NADPH-cytochrome c reductase, heme oxygenase, and ATPase activities were studied in viable kidney cells isolated from rats submitted to unilateral kidney damage (cortical electrocoagulation) and during the development of acute renal failure subsequent to excision of the contralateral undamaged kidney. Measurements of blood pH, plasma total and ionized calcium, phosphorus, creatinine, kidney histology, and phosphorus nuclear magnetic resonance spectroscopy determinations of phosphorus-containing compounds in kidney tissue were also performed. Seventy-two hours after unilateral kidney damage, no significant changes were observed in blood pH or in the plasma parameters studied. During this period, a significant increase in the activity of the 25-hydroxyvitamin D3 hydroxylases could be demonstrated in the cells of the contralateral undamaged kidney. A similar pattern of compensatory rise in the activity of the other enzymes studied was not detected. However, in the damaged kidney viable cells, the hydroxylase activities remained unchanged relative to those in sham-operated controls, despite a 5-fold increase in the inorganic phosphate content and a marked decrease in the organophosphorus and ATP content of this tissue. During the development of acute renal failure, a significant decrease in the activity of the hydroxylases occurred only when the rise in plasma creatinine concentration suggested severe renal insufficiency.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗

PubMed1983

Immunoperoxidase localization of estrogen receptors in human brest carcinoma.

Monoclonal antibodies to the estrogen receptor protein were used to evaluate the specificity of the peroxidase antiperoxidase (PAP) method for localization of estrogen receptors (ER) in human breast carcinoma. Twenty-five cases of breast carcinoma were selected, and they were roughly classified as ER-rich and ER-poor tumors based on ER levels as determined by dextran-coated charcoal (DCC) assay. ER-rich tumors showed strongly positive cytoplasmic and, to a lesser degree, nuclear staining. Both the cytoplasmic and nuclear staining were less intense in ER-poor tumors, and the staining intensity varied from one to another cell population in the same tumor. Completely negative cells were also observed. The results of the PAP and DCC methods correlated fairly well in ER-rich tumors but not in ER-poor tumors. The PAP method provided visual localization of ER combined with excellent tissue morphology. Application of both methods (DCC and PAP) may provide better assessment of the estrogen receptor levels in breast carcinomas.

Breast Neoplasms↗

PubMed1982

Rapidly progressive glomerulonephritis superimposed on diabetic glomerulosclerosis. Recognition and treatment.

Two patients with long-standing diabetes mellitus and diabetic retinopathy were evaluated for declining renal function and heavy albuminuria. Initially, diabetic glomerulosclerosis was suspected as the cause of progressive glomerulopathy. However, in both patients the rate of loss of glomerular filtration rate was greater than that usually seen in diabetic glomerulosclerosis, and the urine sediment contained many RBC casts. These findings led to renal biopsy, which demonstrated crescentic glomerulonephritis superimposed on diabetic glomerulopathy. Both patients were treated with prednisone and cyclophosphamide and both experienced substantial improvement in renal function. These experiences demonstrate the importance of searching for evidence of a superimposed treatable glomerulopathy in the diabetic patient with glomerulopathy and advancing renal insufficiency.

Adult↗