The detrimental effects of adrenocorticosteroid therapy in HBsAg-positive chronic active hepatitis: fact or artifact?
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Adrenal Cortex Hormones↗
Biomedical subjects
R D Soloway
Publications and source records attributed to R D Soloway.
Mucin glycoprotein content of human pigment gallstones.
Mucin glycoproteins, a secretory product of the gallbladder, are thought to contribute to the matrix or nucleus of gallstones. Human black pigment stones originate in the gallbladder and have as their major constituent calcium bilirubinate, as well as inorganic salts and small amounts of cholesterol. The object of this study was to estimate the amount of glycoprotein in black pigment stones and to isolate gallbladder mucin from dissolved stones. Black pigment stones containing 18 to 65% calcium bilirubinate were first dissolved in 12.5 mM EDTA/0.1 N NaOH and decolorized, then subjected to glycoprotein assay. The mean glycoprotein content of eight stones was 12.4%. In separate experiments, pigment stones were partially dissolved by brief exposure to EDTA/NaOH to minimize glycoprotein breakdown, and the glycoproteins isolated by gel filtration and ultracentrifugation. Pigment stones contained two glycoprotein fractions on Sepharose 4B; a high molecular weight mucin glycoprotein in the void volume and a lower molecular fraction in the included volume. Mucin was further purified by density gradient ultracentrifugation in cesium chloride. Three separate mucin fractions had an average buoyant density of 1.48 gm per ml which is typical for these glycoproteins. Bile pigment was associated with high molecular weight mucin even after extensive dialysis, gel filtration, and density gradient ultracentrifugation. The identity of mucin was further established by beta-elimination of glycoproteins in alkaline borohydride which yielded galactosaminitol from cleavage of O-glycosidic bonds. Our results indicate that mucin glycoproteins are present in significant concentrations in human black pigment stones and can be purified from stones solubilized in EDTA/NaOH. The association of bile pigment with gallbladder mucin, even after extensive purification, is consistent with the hypothesis that mucin contributes to the matrix of pigment gallstones.
Bilirubin↗
Black and brown pigment gallstones differ in microstructure and microcomposition.
The two subtypes of pigment gallstones, black and brown stones, differ in chemical composition and pathogenesis. We examined a black bilirubinate stone and a black phosphate stone (which represented opposite ends of the compositional spectrum of black noncarbonate stones), a black carbonate stone, and a brown pigment stone using scanning electron microscopy and microchemical techniques to determine if stone microstructure and microcomposition reflected different patterns of formation. The cross-sectional surfaces of the black bilirubinate and black phosphate stones were smooth and homogenous. Electron probe microanalysis demonstrated high concentrations of sulfur and copper in the center of the black bilirubinate stone; sulfur was in a low valence state consistent with disulfide linkages in proteins. The brown stone was rough-surfaced with lamellated bands on cross-section. The lighter-colored bands in this stone contained virtually all of the detected calcium palmitate, while the darker sections contained much more calcium bilirubinate. Plasma oxygen etching demonstrated a network of protein interdigitating with calcium bilirubinate salts in the black bilirubinate and black phosphate stones but not in the black carbonate or brown stones. Argon ion etching demonstrated that calcium bilirubinate was in a closely packed rod-shaped arrangement in all three black stones but not in the brown stone. We conclude that the marked differences in structure and composition between the black noncarbonate and brown pigment gallstones support the hypothesis that the two major pigment gallstone types form by different mechanisms. In addition, the layered structures of the black carbonate and brown stones suggest that stone growth is affected by cyclic changes in biliary composition.
Argon↗
Composition of pigmented centers of cholesterol gallstones.
Most cholesterol gallstones have visually pigmented centers, but it is unclear whether this represents simple co-precipitation of pigment with cholesterol during stone nidation or nidation on a true pigment stone center. To clarify this issue, we selected from among 67 sets of cholesterol gallstones, 12 sets with the most conspicuously pigmented centers. The composition of the centers and the peripheries of these 12 stones was analyzed using infrared spectroscopy and compared with that of 10 black pigment gallstones. The pigmented centers of cholesterol stones contained 80.1 +/- 7.9% (mean +/- S.E.) cholesterol, 6.2 +/- 3.4% calcium bilirubinate (only 4 of the 12 centers had measurable calcium bilirubinate), trace amounts of calcium phosphate and no calcium carbonate or calcium palmitate. The peripheral areas of the cholesterol stones contained 91.6 +/- 2.3% cholesterol and no detectable calcium salts. For comparison, the composition of the centers of 10 black pigment gallstones was 13.5 +/- 2.2% cholesterol, 28.2 +/- 5.3% calcium bilirubinate, 5.5 +/- 2.4% calcium phosphate and 10.6 +/- 5.8% calcium carbonate. The composition of only one cholesterol stone center (15.8% cholesterol, 26.8% calcium bilirubinate) resembled that of a pigment stone, but even this center differed from that of a typical pigment stone in that it contained only a trace amount of calcium phosphate and no calcium carbonate. Thus, the chemical composition of pigmented centers of cholesterol gallstones is quantitatively different from that of black pigment stones, suggesting that cholesterol gallstones do not form on a pigment stone nidus.
Bilirubin↗
The calcium ionophore A23187 stimulates glycoprotein secretion by the guinea pig gallbladder.
The purpose of this study was to examine the role of calcium ions in gallbladder glycoprotein secretion in cultured guinea pig gallbladder explants. The calcium ionophore A23187 showed a threshold of 2 micrograms per ml medium for stimulation of secretion of [3H]glucosamine-labeled glycoproteins over a 30 min incubation period. The ionophore at 3 and 5 micrograms per ml medium resulted in a 3- to 4-fold increase in secretion of [3H]glucosamine-labeled glycoproteins. Ionophore-induced stimulation of glycoprotein secretion was abolished by the addition of 0.01 mM verapamil to the medium. To study the effect of changes in extracellular calcium on basal glycoprotein secretion, explants were cultured for 24 hr in media with 0.007, 0.5 or 2.0 mM calcium; no differences in basal glycoprotein secretion were observed. When cultured in medium with 1.0 mM EGTA, basal secretion decreased significantly vs. controls in 0.007 mM total calcium medium. Total [3H]glucosamine incorporation by explants in medium with EGTA was unaltered, however, suggesting that the low level of calcium in the medium was selectively impairing the secretory process. These findings indicate that calcium ions are important in the regulation of gallbladder glycoprotein secretion.
Animals↗
Inhibitors present in blood do not inhibit PCR from buccal cell preparations: case report.
BACKGROUND: Hemochromatosis is a common disease that is characterized by high ferritin levels and/or high iron saturation and mutations in two alleles. MATERIAL AND METHODS: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) is often performed on DNA extracted from blood since blood yields high concentrations of DNA. However, inhibitors can cause PCR failure in DNA extracted from blood thus preventing a molecular diagnosis. RESULTS: This report describes a case where multiple blood draws resulted in unamplifiable DNA. Subsequently, a buccal cell sample was collected and extracted. DNA extracted from the buccal cells yielded amplifiable DNA in contrast to DNA extracted from the patient's blood. In addition, the patient was identified as having a homozygous mutation for one allele of the hemochromatosis gene. CONCLUSION: These results suggests that a buccal cell DNA extraction may be useful in cases where blood samples contain inhibitory substances for PCR.
Blood Proteins↗