Low serum reverse T3 levels in patients with primary hyperparathyroidism

Although patients with primary hyperparathyroidism (1 degree HPT) were euthyroid, we measured serum thyroid hormone levels in 16 patients with 1 degree HPT together with 17 patients with hypercalcemia due to malignant diseases (HCM). In patients with 1 degree HPT, serum levels of T3, T4 and T3U were within normal range, but serum rT3 (reverse T3) levels (205 +/- 37 pg/ml, mean +/- SD) were significantly decreased as compared with those in normal controls (276 +/- 44 pg/ml, P less than 0.01). A significant inverse correlation was observed between the serum levels of rT3 and parathyroid hormone (PTH) (r = 0.54, P less than 0.05). After parathyroidectomy, serum rT3 levels were significantly elevated (240 +/- 56 pg/ml) compared to preoperative levels (P less than 0.01). Low levels of serum rT3 seemed to be attributed to the high levels of serum PTH. On the other hand, serum levels of T3 and T4 were low and serum rT3 levels were high in patients with HCM. Low serum rT3 allows for the differentiation of patients with 1 degree HPT from those with HCM.     

Effect of Exogenous Gangliosides on Amino Acid Uptake and Na+,K+-ATPase Activity in Superior Cervical and Nodose Ganglia of Rats

The effects of some gangliosides on active uptake of nonmetabolizable alpha-aminoisobutyric acid (AIB) and Na+, K+-ATPase and Ca2+, Mg2+-ATPase activities in superior cervical ganglia (SCG) and nodose ganglia (NG) excised from adult rats were examined during aerobic incubation at 37 degrees C for 2 h. In NG, amino acid uptake was greatly accelerated with the addition of galactosyl-N-acetylgalactosaminyl-[N-acetylneuraminyl]-galactosylgluc osyl ceramide (GM1) (85%) and also with N-acetylgalactosaminyl-[N-acetylneuraminyl]-galactosylglucosyl ceramide (GM2) or [N-acetylneuraminyl]-galactosyl-N-acetylgalactosaminyl-[N-acetyl- neuraminyl]-galactosylglucosyl ceramide (GD1a) (43% each) compared with a nonaddition control at a 5 nM concentration. Under identical conditions, Na+, K+-ATPase activity was strongly stimulated with GM1 (180%) and GD1a (93%), whereas Ca2+, Mg2+-ATPase activity showed no change. In SCG, on the other hand, AIB uptake was apparently inhibited (-27%) by addition of GM1, with a slight decrease in Na+, K+-ATPase but no change in Ca2+, Mg2+-ATPase activity in the tissue. Both asialo-GM1, in which N-acetylneuraminic acid is deficient, and Forssman glycolipid, which is not present in nervous tissue, failed to produce any significant increase in both SCG and NG not only in amino acid uptake, but also in Na+, K+-ATPase activity. A kinetic study of active AIB uptake showed that GM1 ganglioside produced an increase in Km with no change in Vmax in SCG, whereas it caused a decrease in Km with a slight increase in Vmax in NG. Treatment of NG and SCG with neuraminidase from Vibrio cholerae, an enzyme that split off sialic acid from polysialoganglioside, leaving GM1 intact, caused little inhibition of the amino acid uptake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Structure and function relationship of staphylocoagulase

The bacterial protein staphylocoagulase binds stoichiometrically to human prothrombin, resulting in a coagulant complex, staphylothrombin. The enzymatic properties of staphylothrombin differ from those of -thrombin in their substrate specificities toward natural and synthetic substrates, in addition to their interaction with protease inhibitors. In order to obtain information about the region of staphylocoagulase that interacts with human prothrombin, staphylocoagulase was cleaved by -chymotrypsin. Limited -chymotryptic cleavage of staphylocoagulase yielded three large fragments, of 43, 30, and 20 kD. The 43-kD fragment exhibited a high affinity for human prothrombin (K_d=1.7 nM), which is comparable to the affinity observed using intact staphylocoagulase (K_d=0.46 nM). A complex of the 43-kD fragment and prothrombin possessed both clotting and amidase activity essentially identical to that observed in a complex of intact staphylocoagulase and prothrombin. The 30-kD fragment exhibited weaker affinity for prothrombin (K_d=120 nM.) While clotting activity was not observed with a complex of this fragment and prothrombin, it nonetheless possessed a weak amidase activity. The 20-kD fragment was found only to bind to prothrombin. The NH₂-terminal sequence analyses of these fragments revealed that the 43-kD fragment constitutes the NH₂-terminal portion of staphylocoagulase, and contains the 30-kD and 20-kD fragments. It is therefore concluded that the functional region of staphylocoagulase for binding and activation of prothrombin is localized in the NH₂-terminal region of the intact protein. The 43-kD fragment contained 324 amino acids with a molecular weight of 38,098. The 43-kD fragment had an unusual amino acid composition based on a sequence in which the sum of Asp (28 residues), Asn (22), Glu (35), Gln (9), and Lys (52) residues accounted for more than 45% of the total. A comparison of the amino acid sequence of the 43-kD fragment with that of streptokinase did not reveal any obvious sequence homology. There was also no sequence homology with that of trypsin, -chymotrypsin, and elastase.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Involvement of the acyl chain of ceramide in carbohydrate recognition by an anti-glycolipid monoclonal antibody: the case of an anti-melanoma antibody,M2590, to GM3-ganglioside

The effect of the chain length of the fatty acid residue of the ceramide moiety of ganglioside G_M3 on the binding ability of monoclonal antibody M2590, which is specific for the carbohydrate structure of G_M3-ganglioside, was examined by means of a direct binding assay on thin layer chromatography plates (TLC immunostaining) and a quantitative enzyme-linked immunosorbent assay (ELISA). Derivatives of G_M3 with a long fatty acid chain reacted with the M2590 antibody, but those with a short fatty acid chain showed no reaction in either assay system. These results suggested that the acyl fatty acid moiety of the ganglioside played an important role in the formation or maintenance of the antigenic structure of the carbohydrate moiety of the ganglioside.     

Effect of calcium overload on the phosphoinositide breakdown in the rat left ventricular papillary muscle

We investigated the effect of Ca²⁺ overload on the phospholipase C-catalyzed hydrolysis of phosphoinositides in the rat left ventricular papillary muscle. Ca²⁺ overload on the papillary muscle was induced by treatment with 0.3 mM ouabain in Ca²⁺-containing medium following either Ca²⁺-containing or Ca²⁺-free superfusion. The phosphoinositide breakdown was evaluated by determining accumulations of [³H]inositol phosphates ([³H]IPs) in the tissues prelabeled with [³H]inositol. Ca²⁺ repletion following Ca²⁺-free superfusion resulted in a rapid but small increase in resting tension that was not followed by contracture, nor was it associated with a significant increase in [³H]IPs accumulations. Treatment with ouabain following Ca²⁺-containing superfusion increased resting tension after a lag period of several minutes and produced contracture associated with an increase in [³H]IPs accumulations. The ouabain induced increases in resting tension, and accumulations of [³H]IPs were significantly potentiated by prior Ca²⁺-free superfusion instead of Ca²⁺-containing superfusion. There was a significant positive correlation between increases in resting tension and the phosphoinositide breakdown. The increased resting tension and the accumulations of [³H]IPs were not antagonized by treatments with prazosin plus atropine or indomethacin, but were abolished by superfusion with Ca²⁺-free buffer solution. Although the enhanced phospholipase C-catalyzed hydrolysis of phosphoinositides appears to be a consequence rather than a cause of increased intracellular Ca²⁺, such a biochemical change may provoke a positive feedback mechanism to develop the muscle contracture through the putative intracellular messenger action of inositol triphosphate and diacylglycerol.Abbreviations [³H]IPs [³H]Inositol Phosphates - IP Inositol Phosphate - IP₂ Inositol Bisphosphate - IP₃ Inositol Trisphosphate - PI Phosphatidylinositol - PI-4-P Phosphatidylinositol-4-phosphate - PI-4,5-P₂ Phosphatidylinositol 4,5-bisphosphate - PRZ Prazosin - ATR Atropine - INDO Indomethacin - min Minutes     

Low density lipoprotein and apoprotein B induce increases in inositol trisphosphate and cytosolic free Ca2+ via pertussis toxin-sensitive GTP-binding protein in vascular smooth muscle cells

Low density lipoprotein (LDL), a major cholesterol-carrying lipoprotein in the plasma, binds to its receptor through apoprotein B (Apo-B). The addition of LDL and Apo-B induced rapid (5 s), but transient increase in the inositol 1,4,5-trisphosphate (Ins-1,4,5-P3) level with K0.5 values of 1.1 and 0.07 microgram/ml, accompanied by increases of cytosolic free Ca2+ concentration [( Ca2+]i), in vascular smooth muscle cells (VSMC). The increases by LDL and Apo-B were both reduced by pretreatment of the VSMC with pertussis toxin. The early change in Ins-1,4,5-P3 involving a GTP-binding protein may function as an initial signal for the action of LDL in VSMC.     

Immunohistochemical study on fetal raphe samples transplanted into the leptomeningeal tissue of 5,6-dihydroxytryptamine-treated adult rats

Summary Pieces of fetal midbrain raphe containing serotonergic and dopaminergic neurons were transplanted into the leptomeningeal tissue (see Fig. 3) of adult host rats that had previously been denervated by treatment with 5,6-dihydroxytryptamine. One, 2 and 5 months after transplantation, the rate of neuronal survival in the grafted tissue and the extent of axonal outgrowth into the host brain were studied by use of serotonin and tyrosine hydroxylase (TH) immunohistochemistry. The survival rate of the grafts in the 1-month group was approximately 70%. Neurons containing either serotonin or catecholamine were demonstrated by means of immunocytochemical procedures in the grafts. Two and 5 months after transplantation, serotonin-immunoreactive nerve fibers were densely distributed throughout the graft tissue, while TH-immunoreactive fiber elements were restricted to an area near the somata of TH-positive neurons. Numerous serotonin-immunoreactive fibers derived from the transplant were found in the leptomeningeal tissue surrounding the graft, on the wall of neighboring blood vessels, and also in the adjacent parenchyma of the host brain. Outgrowing TH-immunoreactive nerve fibers were not observed in the host brain, although such elements occurred in the leptomeningeal tissue and the wall of the larger blood vessels. These results suggest that the serotonergic and catecholaminergic (dopaminergic) neurons located in transplants of the raphe nuclei show different patterns when reinnervating the host tissue.     

Primary structure of an N-linked sugar chain derived from glucoamylase of Rhizopus niveus

The primary structure of the N-linked sugar chain of Rhizopus niveus glucoamylase (major component) was investigated. The carbohydrate moiety was released from the polypeptide backbone by Flavobacterium sp. endo-beta-N-acetylglucosaminidase digestion. Studies using the method of exoglycosidase digestion of the fluorescent pyridylamino derivative, gel-permeation chromatography on Bio-Gel P-4 and 400-MHz 1H-NMR spectroscopy revealed that the most abundant structure is (Man)8-GlcNac-ol.     

A complete deletion mutant of the Escherichia coli dnaKdnaJ operon

Southern hydridization analyses of genomic DNAs from various dnaJ mutants of Escherichia coli showed that mutant K7052, which has well characterized dnaK706 and dnaJ705 double mutantions, is a deletion mutant. The deletion is about 8.0 kb long and encompasses the whole of the dnaKdnaJ operon.     

Plasmid expression and maintenance during long-term starvation-survival of bacteria in well water.

Strains of enteric bacteria and pseudomonads containing plasmid R388::Tnl721 (Tpr, Tcr) or pRO101 (Hgr, Tcr) were starved for over 250 days in sterile well water to evaluate effects of starvation-survival on plasmid expression and maintenance. Viable populations dropped to between approximately 0.1 and 1% of the initial populations. Escherichia coli(pRO101) and Pseudomonas cepacia(pRO101) lost both viability and plasmid expression at a lower rate than strains containing R388::Tnl721. Three patterns of host-plasmid interaction were detected: (i) no apparent loss of plasmid expression, (ii) loss of plasmid expression on initial recovery with subsequent expression upon resuscitation, and (iii) loss of capability to produce functional plasmid resistance.