An outbreak of epidemic diarrhoea in adults caused by a new rotavirus in Anhui Province of China in the summer of 1983

Shexian County of Anhui Province in East China experienced a severe outbreak of nonbacterial diarrhoea in May and June of 1983. Over 20,0000 cases were reported. Most were adults of 20 to 50 years old. The isolated virus was morphologically indistinguishable from ordinary infantile rotavirus, but CF and ELISA tests showed that the new virus lacked the common group-A antigen shared by ordinary rotavirus. Nine of 10 convalescent-phase and three paired sera of patients showed antibody positive, with a greater than four-fold antibody rise against new rotavirus in the CF test. Seventeen faecal samples from patients showed identical, and special, electropherotype. They all had a double-stranded RNA with 11 discrete segments. The RNA profiles were quite different from those of reference rotavirus Wa strain and ordinary infantile rotaviruses. Third and 4th segments were near to each other, 5th and 6th segments were very close, but 7th, 8th, and 9th segments were widely separated. This study indicates the new virus can be identified as part of a new group of rotaviruses. This new rotavirus has been incriminated as the causative agent of the epidemic.

Vasopressin and renin response to plasma volume loss in spontaneously hypertensive rats

Abnormalities in the vasopressin (VP) and renin-angiotensin systems have been described in spontaneously hypertensive rats (SHR). Responsiveness of these systems to a decrease in plasma volume was examined in the SHR at 6, 8, and 18 wk of age and compared with responses in age-matched normotensive Wistar and Wistar Kyoto rats (WKY). Trunk blood was collected 3 h after administration of 2 ml/100 g body wt of 0.9% saline, 15 or 30% polyethylene glycol (PEG), and in one group of conscious 8- and 18-wk-old rats, mean arterial pressure was monitored following PEG administration. Hematocrit and serum VP increased significantly in both strains at all ages following PEG. At 6 and 8 wk of age, the VP response to the PEG injection was significantly greater in SHR compared with WKY (P less than 0.005), but at 18 wk the response was comparable in the two strains. Serum renin activity (SRA) also increased in both strains receiving PEG at 6 and 8 wk of age, but the response was suppressed in the SHR relative to the WKY (P less than 0.001). At 18 wk of age, SRA increased in WKY, but the response was totally suppressed in SHR. Renal renin content in a separate group of rats was reduced in 19-wk-old SHR compared with WKY (P less than 0.001) but was not different in 5- and 8-wk-old rats. Thus there appears to be a hyperresponsiveness in the VP system in young SHRs that is not present in the renin-angiotensin system. The divergence in the responsiveness of the renin and VP systems and the attenuation of responsiveness in the VP system in 18-wk SHRs indicate a differential effect of the hypertensive process on the VP and renin systems in the SHR.

Splenic immune effector and suppressor cells in mice bearing a growing plasmacytoma

The occurrence of tumor immunity in mice bearing a growing plasmacytoma (PC) was studied by local adoptive transfer assay. Spleen cells from mice with a large PC but not with a nonpalpable or small PC retarded and often inhibited entirely the growth of homologous PC. They occasionally caused late regression of growing homologous and heterologous PC. The individual tumor-specific immune effector cells were found to be radiosensitive, non-adherent, Thy 1-positive T-cells. They were resistant to treatment of mice with high-dose cyclophosphamide (CTX). Their generation, however, was abrogated by low-dose CTX and irradiation at the early stage of their development. Spleen cells from PC-bearing mice treated with high-dose CTX were enhanced in their effector activity, suggesting the co-existence of CTX-sensitive suppressor cells. The suppressor cells could be demonstrated in spleens of mice bearing a heterologous PC and were found also to be radiosensitive, non-adherent, Thy 1-positive T-cells. Their generation was blocked by treatment of mice with CTX during the early stage of PC development. These findings provide evidence for the occurrence of immune effector T-cells in mice with a growing PC. This immunity appears to be down-regulated by CTX-sensitive suppressor cells.

Neonatal hypertension from a unilateral multicystic dysplastic kidney

Multicystic renal dysplasia is an extremely uncommon cause of hypertension in children and the few reported cases have not been of newborns. We report on a neonate in whom severe hypertension associated with elevated peripheral plasma renin resulted from a unilateral multicystic dysplastic kidney. Hypertension and plasma renin activity normalized after unilateral nephrectomy. No evidence of perfusion or excretory renal function in the dysplastic kidney was present on a radionuclide renal scan. This child demonstrates a relationship between hypertension and unilateral multicystic renal dysplasia.

Influence of renal perfusion pressure on alpha- and beta-adrenergic stimulation of renin release

Experiments were performed in pentobarbital-anesthetized dogs to 1) determine if neural stimulation of renin release can be mediated by renal alpha-adrenoceptors at renal nerve stimulation (RNS) frequencies that have little or no effect on total renal blood flow (less than or equal to 1.2 Hz) and 2) ascertain whether alpha-adrenergic control of renin release is affected by renal perfusion pressure (RPP). The renal nerves were electrically stimulated both in the absence of RPP control and with RPP controlled near 85 mmHg. Decreased RPP lowered the threshold for neurogenic stimulation of renin release from less than or equal to 1.2 to 0.3 Hz. beta-Adrenoceptor blockade with propranolol blunted the renin secretion rate (RSR) response to graded RNS (0.3-5.0 Hz), but the extent of inhibition during low-frequency RNS was dependent on RPP. Propranolol prevented increased RSR at 0.6-1.2 Hz RNS when RPP was 111-120 mmHg but not when RPP was 85 mmHg. Combined alpha- and beta-blockade with prazosin and propranolol totally prevented increased RSR during 0.6-1.2 Hz RNS at reduced RPP. In summary, both alpha- and beta-adrenoceptors mediate neural stimulation of renin release at RNS frequencies that do not decrease total renal blood flow when RPP is 85 mmHg.

A simple model for estimating the hemolytic rate in patients with sickle cell anemia

The pathophysiologic processes of hemolysis in sickle cell anemia were formulated by a simple mathematical model that assumed a unimodal bone marrow erythrocyte population and a finite probability of random destruction of red blood cells (RBCs) in the circulation. Recognizing that the hemolytic rate of marrow RBCs is likely to be distributed normally around a mean hemolytic rate, we simplified the model by using the mean hemolytic rate as representative of the entire marrow RBC population. The model thus constructed allows an easy estimation of the mean steady-state hemolytic rate simply by measurement of reticulocyte counts and hematocrit levels. When the model was applied to data from 43 patients with sickle cell anemia, the estimated mean hemolytic rates based on the model correlated significantly with the published hemolytic rates obtained by diisopropylphosphofluoridate-RBC survival studies of the peripheral blood, but were generally greater than the published rates. This discrepancy was postulated to be the result of an enrichment of RBCs with smaller hemolytic rate in the circulation. The results of computer simulation studies were consistent with this hypothesis and suggest that the variation in the hemolytic rate for marrow RBCs is on the order of 10%. This simplified model may serve as a close approximation of this pathophysiologic system. The estimates of the steady-state hemolytic rate provided by the model should be clinically useful, especially when repeated estimations are required. The method of calculation is illustrated.

Renal norepinephrine overflow during graded renal nerve stimulation before and after beta-adrenoceptor blockade

These experiments were designed to determine if renal venous norepinephrine (NE) overflow provides a valid index of renal sympathetic nerve activity. In addition, we evaluated the effect of beta-adrenoceptor blockade on renal NE overflow during graded renal nerve stimulation in order to examine the possibility that presynaptic beta-adrenoceptors facilitate neuronal release of NE in the kidney. In 6 pentobarbital-anesthetized dogs, the renal nerves were transected to remove tonic nerve activity and the distal ends were electrically stimulated (8-25 V, 0.5 ms) over the range of 0.3-5.0 Hz for consecutive 4-min periods. NE overflow rate was calculated as the product of the veno-arterial NE concentration difference and renal plasma flow. Control values of NE overflow (-8.7 +/- 1.8 ng/min) demonstrated net clearance of NE from the renal circulation. NE overflow rate rose to -3.1 +/- 2.2, 1.0 +/- 4.0, and 33.2 +/- 15.4 ng/min at 0.3, 0.6, and 1.2 Hz stimulation, respectively, with no accompanying change in renal blood flow. At 2.4 and 5.0 Hz, renal blood flow decreased by 21 +/- 4% and 37 +/- 3%, but there was no further increase in NE overflow rate (38.8 +/- 9.4 and 27.8 +/- 6.5 ng/min). Propranolol (0.5-1.0 mg . kg-1 plus 0.4-0.5 mg . kg-1 i.v., n = 4) did not alter the effect of nerve stimulation on either NE overflow or renal blood flow. Thus we were unable to demonstrate the presence of functional renal presynaptic beta-adrenoceptors. Further, our data indicate that renal norepinephrine overflow rate is not always a reliable index of renal nerve activity, since NE overflow was not proportional to renal nerve stimulation rate at frequencies high enough to cause vasoconstriction.

Diffusible suppressor factor from splenic macrophages in murine plasmacytoma

The immunosuppressive effect of splenic macrophages (M phi) in mice bearing plasmacytoma was previously shown to be mediated by a diffusible factor. This diffusible suppressor factor (DSF) was found to be non-dialysable and sensitive to heating to 56 degrees C and to the proteolytic action of trypsin. The suppressor factor could be removed from culture supernatants by binding to ligands that specifically bind to corresponding myeloma proteins. DSF from splenic suppressor M phi of mice bearing MOPC 315 was capable of binding dinitrophenyl L-lysine, and that from mice bearing MOPC 104E, dextran S. The suppressor factor apparently cross-reacted with anti-idiotypic antibody to the corresponding myeloma protein, but did not interact with anti-isotypic antibody to mouse immunoglobulins (Ig). A higher concentration of mouse Ig than that found in DSF preparations did not have a suppressive effect. Metabolic inhibitors for RNA and protein, but not DNA synthesis effectively blocked the production of DSF. These findings suggest that DSF is a non-Ig protein that may have a structural similarity to myeloma idiotype. Continuous RNA and protein synthesis is required for the elaboration of DSF by splenic suppressor M phi in cultures.

Biphasic effect on platelet aggregation by phospholipase a purified from Vipera russellii snake venom

A basic phospholipase A was isolated from Vipera russellii snake venom. It induced a biphasic effect on washed rabbit platelets suspended in Tyrode's solution. The first phase was a reversible aggregation which was dependent on stirring and extracellular calcium. The second phase was an inhibitory effect on platelet aggregation, occurring 5 min after the addition of the venom phospholipase A without stirring or after a recovery from the reversible aggregation. The aggregating phase could be inhibited by indomethacin, tetracaine, papaverine, creatine phosphate/creatine phosphokinase, mepacrine, verapamil, sodium nitroprusside, prostaglandin E1 or bovine serum albumin. The venom phospholipase A released free fatty acids from synthetic phosphatidylcholine and intact platelets. p-Bromophenacyl bromide-modified venom phospholipase A lost its phospholipase A enzymatic and platelet-aggregating activities, but protected platelets from the aggregation induced by the native enzyme. The second phase of the venom phospholipase A action showed a different degree of inhibition on platelet aggregation induced by some activators in following order: arachidonic acid greater than collagen greater than thrombin greater than ionophore A23187. The longer the incubation time or the higher the concentration of the venom phospholipase A, the more pronounced was the inhibitory effect. The venom phospholipase A did not affect the thrombin-induced release reaction which was caused by intracellular Ca2+ mobilization in the presence of EDTA, but inhibited collagen-induced release reaction which was caused by Ca2+ influx from extracellular medium. The inhibitory effect of the venom phospholipase A and also lysophosphatidylcholine or arachidonic acid could be antagonized or reversed by bovine serum albumin. It was concluded that the first stimulatory phase of the venom phospholipase A action might be due to arachidonate liberation from platelet membrane. The second phase of inhibition of platelet aggregation and the release of ATP might be due to the inhibitory action of the split products produced by this venom phospholipase A.

Purification and properties of the main coagulant and anticoagulant principles of Vipera russellii snake venom

Vipera russellii venom was separated into thirteen fractions by means of DEAE-Sephadex A-50 column chromatography. Fraction III possessed anticoagulant and phospholipase A activities and Fraction XI possessed procoagulant and caseinolytic activities, both were further purified by gel filtration on Sephacryl S-200 column. Purified procoagulant (Component II) was a two-chain protein with molecular weight of 86 000 consisting of A-chain (Mr 66 000) and B-chain (Mr 20 000). It was a glycoprotein containing 7.8% neutral sugar and 715 amino-acid residues. The procoagulant activity was 10-times that of the crude venom. It was an acidic proteinase with isoelectric point of pH 4.2. Upon heat treatment at 60 degrees C, Component II was stable at pH 5.5 and 7.2 for 3 h, but was destroyed completely after 30 min at pH 8.9. It was devoid of esterase or amidase activity. Purified anticoagulant (Component I) was a single peptide chain with molecular weight of 16 000. It was carbohydrate free and contained 136 amino-acid residues. It was a basic protein with an isoelectric point of larger than pH 10. It was a potent phospholipase A with an enzymatic activity of 510 +/- 30 mumol/min per mg using phosphatidylcholine as substrate, and 1 microgram/ml was sufficient to cause 100% hemolysis by the indirect hemolytic method. Upon heat treatment at 90 degrees C, Component I was heat stable at pH 5.5 for more than 3 h, but was destroyed completely after 2 h at pH 7.2 and 8.9. The anticoagulant activity of Component I could be neutralized by platelet factor 3, tissue thromboplastin and cephalin.

Optical activity and conformation of beta-bungarotoxin in solution

beta-Bungarotoxin, which consists of two polypeptide chains (A- and B-chain), in the venom of Formosan banded krait is stable in 7.5 M urea but can be denatured in 6.0 M guanidine hydrochloride. Its conformation remains virtually the same in solvents of lower polarity than water such as a mixture of 1,2-ethanediol-water (4:1 by volume). The circular dichroism spectrum in water shows a double minima at 222 and 209 nm, which is characteristic of the helical structure. The ellipticities at these two wavelengths indicate that the helical content of this toxin is not high. Comparing how guanidine hydrochloride effects the helix-coil transition of the toxin with that of phospholipase A2's which are structurally homologous to A-chain implicates that the two polypeptide chains should be coexisted and interacted with each other in order to maintain the active conformation of beta-bungarotoxin. Removal of eight amino acid residues from the N-terminus of the A-chain by action of CNBr on beta-bungarotoxin does not disrupt the polypeptide folding but abolishes the neurotoxicity.

Separation of isoenzymes of glucose-6-phosphate dehydrogenase from human erythrocytes by two-dimensional gel electrophoresis

Isoelectric focusing performed in 6.0% polyacrylamide gel in the presence of 1.0 M urea separates well the various molecular forms of glucose-6-phosphate dehydrogenase from human erythrocytes. At least seven sharp bands appear in the gel pattern, which vary both in isoelectric points and in the relative intensity. Their isoelectric points are at pH 6.88 for band 1, pH 6.79 for band 2, pH 6.64 for band 3, pH 6.50 for band 4, pH 6.39 for band 5, pH 6.19 for band 6, and pH 6.10 for band 7. A second-dimensional disc electrophoresis performed in a polyacrylamide gel slab resolves each band into two components, a slow and a fast component defined according to their mobilities in the disc gel. The slow component constitutes the major portion of each band. All the seven slow components appear to be dimer having a molecular weight between 98,000-94,000. They belong to "change isomers" having identical molecular size but containing different net changes. The molecular weight of the fast components is between 66,800-50,600. These fast components might be monomer or the digested products of slow components.

Membrane disintegration and hemolysis of human erythrocytes by snake venom cardiotoxin (a membrane-disruptive polypeptide)

The action of 7.2 microM cardiotoxin on 0.25% (v/v) human erythrocytes in plasma extender solution was studied by osmotic fragility and hemolysis. The toxin loosened the membrane rigidity without lysis for about 25 min and then the cells hemolyzed for about 6 h at 37 degrees. The membrane was not perturbed at 15 degrees. The hemolysis of cells was optimal at 37 degrees and virtually stopped below 20 degrees. Both events could be suppressed by adding inorganic salts or toxin antibody. Once the membrane was loosened, the addition of phospholipase A2 would potentiate the disintegration of erythrocytes. In contrast, hemolysis of erythrocytes by (Lys)n lacked a non-lytic period and was temperature independent and insensitive towards salts and phospholipase A2.

Suppressor activity of splenic macrophages in murine plasmacytoma (PC) is inhibited by PC specific ligands

Spleens of BALB/c mice with plasmacytoma contain macrophages (M phi) which were found to suppress the in vitro immune function of normal splenic cells through a diffusible factor. The suppressor activity of these macrophages was reversibly inhibited by ligands specific for the corresponding PC globulin, but not by anti-idiotypic antibody. Anti-idiotypic antibody with complement, however, abrogated the suppressor function, presumably by cytotoxicity. Anti-isotype with complement was ineffective. These findings suggest binding of ligand to a surface receptor of the suppressor M phi that although clearly not PC globulin, may be structurally similar to the PC idiotype. These receptors are retained in 3 day cultures of macrophages and are not removed by intensive washing. Ligand binding appears to modulate the suppressor function of M phi through blocking of the production of diffusible suppressor factor.