Metabolism of sitosterol by a Pseudomonas species

Fermentation of sitosterol by a Pseudomonas species (SK-25) resulted in the formation of 5-stigmastene-3 beta, 7 alpha-diol; 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol; 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol and 5 alpha-stigmastan-3 beta, 5,6 beta-triol. The metabolites were characterized by a variety of conventional chemical and spectrometric techniques.

Agonist specific effects of guanine nucleotides on muscarinic cholinergic receptors in rat anterior pituitary membranes

The effects of guanine nucleotides on the binding affinity of muscarinic cholinergic receptors for muscarinic agents were studied in rat anterior pituitary membranes using direct ligand binding methods with [3H]quinuclidinyl benzylate, GTP and Gpp(NH)p at a concentration of 0.1 mM markedly decreased the binding affinity of the agonist, oxotremorine, for the receptors but had no effect on the binding of the antagonist, atropine. Mg2+ (1 mM) on the other had markedly increased the binding affinity of oxotremorine but not that of atropine. Thus, it is conceivable that the release of the growth hormone or the inhibition of prolactin release by acetylcholine, which we and others have previously shown, is modulated by the opposite actions of guanine nucleotides and divalent metal ions such as Mg2+.

Glycoprotein synthesis in colonic epithelial cells from rats

Viable colonic epithelial cells from rats were isolated by a non-enzymatic procedure using EDTA. The isolated cells were fractionated by sedimentation through at 15% to 35% discontinuous Ficoll gradient to yield cells differing in proliferative capacity from three different density regions of the gradient. Glycoprotein synthesis of these fractionated cells was examined in terms of their ability to absorb and incorporate labeled glucosamine and fucose into trichloracetic acid precipitable material. Glycoprotein synthesis was highest among cells with intermediate densities, banding in the middle of the gradient (Fraction II). Cytomorphological examination showed that these cells were predominantly goblet type.

An improved embedding method for electron microscopy of lepromata

Spurr's resin mixture has been found to be the embedding material most suitable for electron microscopic studies of lepromata at present. Like methacrylate, it can penetrate well into foamy structures and the leprosy bacilli within foamy structures. On the other hand, like Epon 812, it is stable against the electron beam and can preserve ultrafine structures. Additionally, we have found that the use of dimethylformamide or dimethylsulfoxide instead of propylene oxide as substituter improves the preservation of the ultrafine structures of leprosy bacilli.

A bacteriological and histopathological study of apparently normal skin in lepromatous leprosy

A comparative study of clinically affected and apparently uninvolved skin in lepromatous patients has been undertaken in 22 cases. Parameters studied include skin smears for bacillary Index; bacillary load/gm of tissue and histopathological comparison of granuloma fraction and biopsy index. The results showed that the clinically unaffected sites have a lower bacillary index and lesser bacterial load. Histologically the granulomas were smaller and biopsy index was lower in uninvolved areas. The possible reasons for this comparative less involvement are discussed.

Leprous phlebitis

Six cases of phlebitis of leprous origin affecting the superficial veins have been recorded. This lesion does not seem to be as rare as was previously believed. The clinical and histopathological details of these cases are presented.

Beta adrenergic and muscarinic cholinergic receptors in canine myocardium. Effects of ischemia

Experimental myocardial ischemia produced in dogs by proximal left anterior descending coronary artery ligation is accompanied by relatively rapid (1 h) increases in the number of (-) [3H]dihydroalprenolol binding sites without changing their dissociation constants in ischemic left ventricular tissue. The changes, persist for at least 8 h and are accompanied by marked decreases in myocardial tissue ischemic region norepinephrine content. In contrast, in the same canine model 1 h of proximal left anterior descending coronary artery ligation did not result in a significant change in the number of [3H]quinuclidynl benzilate binding sites of their dissociation constants. However, the number of [3H]quinuclidynl benzilate binding sites (muscarinic cholinergic receptors) are 50--70% greater than (-) [3H]dihydroalprenolol binding sites (beta adrenergic receptors) in canine left ventricular tissue. Thus, the data suggest that proximal left anterior descending coronary artery occlusion for 1 h significantly increases the number of beta adrenergic receptors in ischemic left ventricular tissue without changing the number of muscarinic cholinergic receptors. Whether the ischemia-produced increase in cardiac beta-receptor content is causally related to increased cyclic AMP levels that develop in ischemic tissue and/or an etiologic factor in arrhythmias originating from ischemic myocardial tissue will have to be determined in additional studies.

Influence of volume dilution, lactate, phosphate, and calcium on mitochondrial functions

Oxidative phosphorylation of isolated canine myocardial mitochondria has been evaluated after exposure to different concentrations of phosphate (5--50 mM), lactate ion in excess (5--40 mM, pH 7.4), calcium (50--270 nmol/mg protein), to lactic acidosis (pH 6.3), and to mitochondrial protein dilution (in vitro volume expansion) for 10 min to 8 h. The influence of phosphate and lactate ion addition, lactic acidosis, and in vitro volume expansion on mitochondrial function were studied in the isolation medium (0.18 M KCl, 0.5% BSA (bovine serum albumin), with or without Tris-EDTA, pH 7.4) prior to evaluation of mitochondrial function in the assay medium (0.25 M sucrose, 10 mM Tris-HCl, and 10 mM inorganic phosphate, pH 7.4). The effect of calcium addition was assessed in the assay medium. The results of these studies demonstrate that each of these interventions detrimentally alters mitochondrial oxidative phosphorylative ability. The most severe mitochondrial functional impairment resulted from phosphate or calcium addition. The detrimental effect of phosphate and in vitro volume expansion was partially corrected by the addition of cytochrome c.

Shwartzman Phenomenon in Leprosy

Disturbances of preexieting immunological balance have been thought to bring about episodes of acute hypersensitivity to bacillary antigens of M. leprae. In view of the rare availability of pure M. leprae antigen, some haematological investigation were done simultaneously with hietological study for a better understanding of such supposedly immune complex syndrome. The investigative study comprised: Quantitation of heparin precipitable fraction (HPF) and fibrinogen along with studies on heamoetasis and histological examination of skin biopay. A total of 105 leprosy patients were studied. Significant rise in HPP and fibrinogen values were obeerved in Stable Lepromatous (SL) and Acute Lepromatous Infilltration (ALl) cases. Euglobulin lysis time was increassed in the ALI group only, during the acute phase. Deficiency of factor. V, VII, VIII, IX and XI, either singly or in combination, was noted in ALI patients, but platelets ware normal in all. Hitology revealed evidences of intravascular coagulation in small and medium sized dermal vessels. These obsevations suggest that during the course of lepromatous leproay, pariodically there might occur generalised Shwartizman type of reaction when qualitative and quantitative alteration of fibrinogen leads to its deposition in small blood vesssels.

Regulatory enzymes of carbohydrate and energy metabolism in the rabbit blastocyst

The activities of phosphofructokinase, pyruvate kinase, citrate synthase and creatine kinase were determined in blastocysts from rabbits at 144 h post coitum and in similar blastocysts cultured for 24 h with or without oestradiol-17beta (1 microgrm/ml). There was a significant increase in all the enzymes during the 24-h culture period but oestradiol had no effect.

Cyclic AMP and cyclic GMP in rabbit blastocysts

Concentrations of both nucleotides were significantly higher in Day-6 than in Day-5 blastocysts but the ratio of cAMP to cGMP changed from 0.5 to 1.5.

Creatine kinase BB isoenzyme levels by radioimmunoassay in patients with neurological disease

Creatine kinase BB (CK-BB) isoenzyme was measured by radioimmunoassay in serum and in cerebrospinal fluid from 61 patients with various neurological disorders. Statistically significant elevations of CK-BB isoenzyme in the serum were observed in patients with acute cerebrovascular accidents and in those with seizures and a prolonged alteration in level of consciousness. Statistically significant elevations of CK-BB isoenzyme in the cerebrospinal fluid were also found in patients who had suffered acute cerebrovascular accidents. Some patients with central nervous system infections, acute demyelinating disease, certain drug overdoses, head trauma, and complex migraine also had elevations of serum and CSF CK-BB isoenzyme. In 2 patients with elevations of CK-BB isoenzyme, the elevations in serum occurred later than those detected in the cerebrospinal fluid. If CK-BB elevations determined by radioimmunoassay can be demonstrated to be quantitatively related to the extent of brain damage, then these determinations in conjunction with experimental animal models and newer radiological techniques should allow evaluation, in an objective and precise manner, of measures designed to decrease that damage.

Sites and mechanisms of localization of technetium-99m phosphorus radiopharmaceuticals in acute myocardial infarcts and other tissues

This study was performed to elucidate the localization at the cellular level of technetium-99m phosphorus ((99m)Tc-P) radiopharmaceuticals in acute myocardial infarcts and the mechanisms responsible for (99m)Tc-P uptake in acute myocardial infarcts and other tissues. In 20 dogs with proximal left anterior descending coronary arterial ligation for 1-3 days, elevated calcium levels were measured at all sites of increased (99m)Tc-P uptake (acute myocardial infarcts, necrotic thoracotomy muscle, lactating breast, and normal bone); however, a consistent linear relationship between (99m)Tc-P and calcium levels was not observed. A strong correlation (r = 0.95 and 0.99, n = 2 dogs) was demonstrated between levels of (3)H-diphosphonate and (99m)Tc-P in infarcted myocardium. Autoradiographic studies with (3)H-diphosphonate revealed extensive labeling in the infarct periphery which contained necrotic muscle cells with features of severe calcium overloading, including widespread hypercontraction as well as more selective formation of mitochondrial calcific deposits. Autoradiography also demonstrated labeling of a small population of damaged border zone muscle cells which exhibited prominent accumulation of lipid droplets and focal, early mitochondrial calcification. Cell fractionation studies revealed major localization of both (99m)Tc-P and calcium in the soluble supernate and membrane-debris fractions of infarcted myocardium and less than 2% of total (99m)Tc-P and calcium in the mitochondrial fractions; however, electron microscopic examination showed that mitochondria with calcific deposits were not preserved in the mitochondrial fractions. In vitro studies evaluating the role of serum protein binding on tissue uptake of (99m)Tc-P agents demonstrated that, in spite of significant complexing with serum proteins, serum (99m)Tc-P activity retained the ability to adsorp to calcium hydroxyapatite and amorphous calcium phosphate. In vivo studies showed that concentration of human serum albumin (labeled with iodine-131) in infarcted myocardium reached a maximum of only 3.8 times normal after a circulation time of 96 h, whereas (99m)Tc-P uptake was at least 10 times normal after a circulation time as short as 1 h. It is concluded that: (a) (99m)Tc-P uptake in acutely infarcted myocardium, and possibly other types of soft tissue damage, is limited to necrotic and severely injured cells; (b) concentration of (99m)Tc-P results from selective adsorption of (99m)Tc-P with various forms of tissue calcium stores, including amorphous calcium phosphate, crystalline hydroxyapatite, and calcium complexed with myofibrils and other macromolecules, possibly supplemented by calcium-independent complexing with organic macromolecules; and (c) lack of a linear relationship between (99m)Tc-P and tissue calcium levels mainly results from local differences in composition and physicochemical properties of tissue calcium stores and from local variations in levels of blood flow for delivery of (99m)Tc-P agents.

Radioimmunoassay of creatine kinase-B isoenzyme in human sera: results in patients with acute myocardial infarction

A radioimmunoassay was developed to measure serum levels of the B isoenzyme of creatine kinase(ATP: creatine N-phosphotransferase, EC 2.7.3.2) (CPK) in order to evaluate the time course and frequency of MB isoenzyme elevation in patients with acute myocardial infarction. The method can identify as little as 0.2 ng of the B portion of the CPK-MB isoenzyme, does not significantly crossreact with CPK-MM isoenzyme, and is not affected by storage of serum at --20 degrees CPK isoenzyme containing B subunits was detected in 48 out of 51 sera from normal adults; serum levels in these individuals ranged between 1.2 and 12.5 ng/ml [mean +/- SEM was 2.7 +/- 0.30 ng/ml]. The mean serum level of CPK-B isoenzyme in a pool of sera obtained from 100 normal subjects was 2.9 +/- 0.35 ng/ml; two patients with rhabdomyolysis that were studied had serum CPK-B isoenzyme levels of 2.5 and 3.5 ng/ml, respectively. In contrast, serum levels of the CPK-B isoenzyme were markedly elevated in sera from 18 patients with acute myocardial infarcts when obtained within 12 hr after hospital admission; the mean +/- SEM concentration was 56 +/- 7.8 ng/ml. We performed serial determinations on 14 patients with acute myocardial infarcts and demonstrated that maximal serum CPK-B levels occurred within the first 12 hr after admission and were lower thereafter. The serum concentration of B-containing CPK isoenzyme in 19 additional patients admitted with chest pain but without acute myocardial infarction was 3.4 +/- 0.50 ng/ml. Thus, radioimmunoassay measurement of CPK-B isoenzyme appears to be a useful and sensitive test for the detection of acute myocardial infarcts in patients.

Abnormal myocardial fluid retention as an early manifestation of ischemic injury

Fifty-seven isolated, blood perfused, continuously weighed canine hearts have been utilized to study the development of abnormal myocardial fluid retention during early myocardial ischemic injury. Inflatable balloon catheters were positioned around the left anterior descending coronary arteries (LAD) of 54 hearts or the proximal left circumflex coronary arteries of three hearts for study of the following intervals of coronary occlusion: a) 10 minutes followed by 20 minutes of reflow, b) 40 minutes followed by either no reflow or by 20 minutes of reflow, and c) 60 minutes without reflow. After 60 minutes of fixed coronary occlusion, histologic and ultrastructural examination revealed mild swelling of many ischemic cardiac muscle cells in the absence of interstitial edema, cardiac weight gain, and obvious structural defects in cell membrane integrity. After 40 minutes of coronary occlusion and 20 minutes of reflow, significant cardiac weight gain occurred in association with characteristic alterations in the ischemic region, including widespread interstitial edema and focal vascular congestion and hemorrhage and swelling of cardiac muscle cells. Focal structural defects in cell membrane integrity were also noted. The development of abnormal myocardial fluid retention after 40 minutes of LAD occlusion occurred in association with a significant reduction in sodium-potassium-ATPase activity in the ischemic area, but with no significant alteration in either creatine phosphokinase or citrate synthase activity in the same region. Despite the abnormal myocardial fluid retention in these hearts, it was possible pharmacologically to vasodilate coronary vessels with adenosine and nitroglycerin infusion to maintain a consistently high coronary flow following release of the coronary occlusion after 40 minutes and to even exceed initial hyperemic flow values following release of the occlusion when adenosine and nitroglycerin infusion was delayed until 15 minutes after reflow. Thus, the data indicate that impaired cell volume regulation and interstitial fluid accumulation and focal structural defects in cell membrane integrity are early manifestations of ischemic injury followed by reflow, but fail to establish a major role for the abnormal fluid retention in altering coronary blood flow prior to the development of extensive myocardial necrosis. In contrast, fixed coronary occlusion for 60 minutes results in mild intracellular swelling but no significant interstitial edema and no obvious structural defects in cell membrane integrity.

Structure of ATP citrate lyase from rat liver. Physicochemical studies and proteolytic modification

ATP citrate lyase was purified by two different procedures from the livers of rats first starved and then fed with a fat-deficient and high carbohydrate-glycerol diet. These enzyme preparations were judged homogeneous by sedimentation equilibrium and polyacrylamide gel electrophoresis. The molecular weight of the native enzyme was around 4.4 X 10(5) as determined by sedimentation equilibrium. On sodium dodecyl sulfate gel electrophoresis the enzyme usually showed a single protein band with an estimated molecular weight of 1.2 X 10(5). A similar value for the molecular weight of the subunit was obtained by gel filtration on 6% agarose in the presence of 6 M guanidinium chloride. The molecular weight of this polypeptide chain was estimated by sedimentation equilibrium to be around 1.1 X 10(5). These results indicated that ATP citrate lyase has a subunit structure of four polypeptides of similar size. The extinction coefficient of the dry protein and its amino acid composition are also reported. Some batches of fully active enzyme, judged to be homogeneous by sedimentation equilibrium and polyacrylamide gel electrophoresis, showed two additional major polypeptides (Mr approximately 7.1 X 10(4) and 5.5 X 10(4)) on sodium dodecyl sulfate gel electrophoresis. Studies on the polypeptides produced by proteolytic modification of the native enzyme by trypsin indicated that the additional protein bands observed on sodium dodecyl sulfate gel electrophoresis with some of the batches of enzyme could have been formed by limited proteolysis ("nicking") of the original 1.1 X 10(5) subunit. Trypsin treatment of the native enzyme did not affect the enzyme activity, whereas chymotrypsin and pronase treatment inactivated the enzyme. The trypsin-treated enzyme, which contained only the two smaller polypeptides, did not differ significantly from the untreated enzyme with respect to sedimentation behavior, phosphorylation by ATP, Km for citrate, and immunoreactivity, but it was more heat-labile than the untreated enzyme. The phosphate group on the phosphorylated "nicked" enzyme was located on the larger polypeptide fragment.

Studies of the mechanism by which hepatic citrate synthase activity increases in vitamin B12 deprivation

Hepatic citrate synthase activity has been shown to be increased 2- to 3-fold in vitamin B12 deficiency. Immunochemical titrations of the affinity chromatography-purified enzyme obtained from liver of animals with B12 deprivation demonstrated that this increase in activity was the result of a true increase in enzyme protein content. When fixed ratios of aliquots of normal and B12-deprived rat liver homogenates were mixed, the activity measured showed no change from the expected total citrate synthase activity based on the admixture ratios. Partial purification of the enzyme resulted in the expected recovery of the enzyme at each of the purification steps. Thus, it is unlikely that the change in enzyme activity in B12 deprivation was due to the presence of a soluble or easily dissociable normally occurring activator or inhibitor. Ouchterlony double diffusion studies, immunochemical titration, and determination of Km vlaues for exalacetate and acetyl-CoA (substrates for citrate synthase) and Ki values for ATP (inhibitor of citrate synthase) all indicated that the enzyme from the B12-deprived livers was structurally the same as that from normal liver. Hepatic citrate synthase degradation rate constants were shown to be essentially unchanged in B12deficiency. The rate of hepatic citrate synthase synthesis, under steady state conditions, was shown to be 2.8-fold greater in the B12-deficient animal than in the normal animal. The increased rate of synthesis appeared to explian the increased enzyme content. Finally, no change in specific activity of the enzyme was seen in brain, heart, or kidney in the B12-deprived animal.

Biochemical and ultrastructural hepatic changes during vitamin B12 deficiency in animals and man

Vitamin B12 deficiency has been shown to result in an increase in content and activity of the hepatic cytosolic enzymes of fatty acid synthesis. The present study demonstrated that ATP citrate lyase, an enzyme whose activity has been positively correlated with rates of fatty acid biosynthesis, also increased in the livers of B12-deficient animals. Total and specific activity of hepatic citrate synthase, an enzyme whose activity is unaffected by a variety of dietary and hormonal changes, also was found to be increased in the B12-deprived state. By contrast, the activity of hepatic succinate-cytochrome c reductase, a portion of a multicomponent enzyme complex synthesized in part within the mitochondria, was unchanged in B12 deficiency. Vitamin B12 deprivation resulted in an increase in hepatic mitochondrial cristae membranes in both animals and man. Histochemical and chemical analysis demonstrated increased glycogen in the liver cells from B12-deficient animals and man. Thus, in the livers from vitamin B12-deficient animals there is an increased activity of the otherwise highly constant Krebs cycle enzyme citrate synthase, and in both animals and man there are increased mitochondrial cristae membranes.

Purification of and mechanism studies on citrate synthase. Use of biospecific adsorption-elution techniques

Citrate synthases from animal tissues were found to bind to Sepharose-"ATP." A pure preparation of citrate synthase was obtained from a crude fraction of rat heart by the specific elution of the enzyme from the Sepharose-"ATP" with the dead end complex-forming substrates, oxalacetate and CoA. The proposed mechanisms of citrate synthase, obtained from steady state kinetics, were examined in light of the elution pattern of the enzyme obtained using combinations of substrates and substrate analogs.