Calcium regulation by lens plasma membrane vesicles.

The role of the plasma membrane in the regulation of lens fiber cell cytosolic Ca2+ concentration has been examined using a vesicular preparation derived from calf lenses. Calcium accumulation by these vesicles was ATP dependent, and was releasable by the ionophore A23187, indicating that calcium was transported into a vesicular space. Calcium accumulation was stimulated by Ca2+ (K1/2 = 0.

Abnormal sarcoplasmic reticulum ryanodine receptor in malignant hyperthermia.

Previous studies have demonstrated that skeletal muscle from individuals susceptible to malignant hyperthermia (MH) has a defect associated with the mechanism of calcium release from its intracellular storage sites in the sarcoplasmic reticulum (SR). In this report we demonstrate that the [3H]ryanodine receptor of isolated MH-susceptible (MHS) porcine heavy SR exhibits an altered Ca2+ dependence of [3H]ryanodine binding at the low affinity Ca2+ site as well as a lower Kd for ryanodine (92 versus 265 nM) when compared to normal porcine SR. The Bmax of the normal and MHS [3H] ryanodine receptor (9.

Drosophila S virus, a hereditary reolike virus, probable agent of the morphological S character in Drosophila simulans.

Isometric reolike virions were found in all the examined Drosophila simulans flies from two strains (SimES-st and Israel-st) presenting the S phenotype, a maternally inherited morphological trait (abnormalities of bristles). Normal flies of both strains appeared virus-free. Virions were found in the cytoplasm of male and female gonads and epidermal cells, including the bristle-forming cells, which appeared disorganized.

Site-specific derivatives of wheat germ calmodulin. Interactions with troponin and sarcoplasmic reticulum.

Wheat germ calmodulin (CaM) was derivatized at its single cysteine (Cys27) with either the fluorescent reagent, N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonic acid (I-EDANS) or the photoactivable cross-linker benzophenone-4-maleimide. Comparison of the native and derivatized wheat germ CaMs with native bovine testis CaM indicates that the concentrations of these proteins required for half-maximal stimulation of either erythrocyte membrane Ca2+-ATPase activity or cardiac sarcoplasmic reticulum phosphorylation are very similar. Affinity labeling of troponin subunits with 125I- and benzophenone-4-maleimide-labeled CaM demonstrates CaM binding to troponin I (TnI) and troponin T (TnT) in binary complexes, as well as to both subunits in the CaM.

[Generalized mucormycosis. Apropos of a case caused by Absidia corymbifera].

This is the case of a woman, 49 year old, suffering from acute lymphoblastic common leukemia, who died from respiratory and cardiac insufficiency 47 days after the onset of aplasia. Autopsy revealed cardiac and cerebral dissemination of pulmonary mycosis. Absidia corymbifera (Mucoraceae, Phycomycete) was shown by culture to be the pathogen involved.

Erythrocyte membrane ATPase and calcium pumping activities in porcine malignant hyperthermia.

To investigate possible abnormalities in erythrocyte membrane enzyme activities in the pharmacogenetic disorder MH, membrane ATPase activities have been examined in erythrocyte ghosts prepared from red blood cells of MHS and normal swine. While no differences were noted in Mg2+-ATPase activities, the (Na+, K+)-ATPase activity of MHS erythrocyte ghosts was less than that of normal ghosts. Ca2+-ATPase activity exhibited low- and high-affinity Ca2+-binding sites in both types of erythrocyte ghost.

Temperature-dependent abnormalities of the erythrocyte membrane in porcine malignant hyperthermia.

The temperature dependence of ATPase activities and stearic acid spin label motion in red blood cells of normal and MH-susceptible pigs have been examined. Arrhenius plots of red blood cell ghost Ca-ATPase and calmodulin-stimulable Ca-ATPase activities were identical for both normal and MH erythrocyte ghosts. Arrhenius plots of Mg-ATPase activity exhibited a break (defined as a change in slope) at 24 degrees C in both MH and normal erythrocyte ghosts.

The instability of the TE-like mutation Dp(2:2)GYL of Drosophila melanogaster is intimately associated with the hobo element.

We have characterized molecularly several derivatives of the TE-like element Dp(2:2)GYL of Drosophila melanogaster. This highly unstable mutation occurred in a dysgenic cross involving the 23.5 MRF chromosome, and represents an inverted insertional duplication of approximately 130 polytene bands of the paternal 2L, at 50AB of the right arm of the maternal 2R.

Increased skeletal muscle acetylcholinesterase activity in porcine malignant hyperthermia.

The content and distribution of acetylcholinesterase (AChE) activity in the skeletal muscle disorder malignant hyperthermia (MH) was examined. The AChE activity of sarcolemma membranes isolated from MH-susceptible (MHS) swine was increased twofold when compared with normal sarcolemma. The total AChE activity of muscle extracts was also doubled in MHS tissue; however, the relative distribution between low-salt extractable (globular forms) and high-salt extractable (asymmetric forms) AChE activities were similar in MHS and normal muscle.

Phospholamban stoichiometry in canine cardiac muscle sarcoplasmic reticulum.

Treatment of cardiac sarcoplasmic reticulum with the crosslinking reagent dithiobis (succinimidyl propionate) in the presence of 125I-calmodulin, resulted in the formation of a 40,000-dalton affinity labeled component, consisting of a 1:1, phospholamban: 125I-calmodulin complex. In parallel experiments, sarcoplasmic reticulum was phosphorylated in the presence of calmodulin and [gamma-32P]ATP, and then treated with the crosslinking reagent to produce an affinity labeled component consisting of a 1:1, calmodulin: 32P-phospholamban complex. These experiments permitted determination of the amount of 125I and 32P incorporated into the 40,000-dalton complexes, as well as the amount of 32P incorporated into the 23,000-dalton form of phospholamban.

[Not Available].

The conditional potentials of redox systems involving protons, such as those of uranium, vanadium and arsenic, have been studied as a function of phosphoric acid concentration (1-14M) with ferricinium/ferrocene as comparison system. The influence of sulphate and fluoride on the conditional potential of the U(VI)/U(IV) couple, and uranium-iron and uranium-silver interactions are considered.

[Not Available].

The conditional potentials of redox systems not involving protons have been studied as a function of phosphoric acid concentration (1-14M), with the ferricinium/ferrocene couple as the comparison system. The following systems were considered: Cu(II)/Cu, Cd(II)/Cd, Sn(II)/Sn, Zn(II)/Zn, Ag(I)/Ag, Pb(II)/Pb, Hg(II)/Hg, Bi(III)/Bi and particularly Fe(III)/Fe(II) and Fe(II)/Fe. The hexacyanoferrate(III)/hexacyanoferrate(II) and iodine/iodide couples were also studied.

Plasma-dependent and -independent mechanisms of platelet aggregation induced by human tumour cell lines.

Tumour cell induced platelet aggregation (TCIPA) may facilitate haematogenous tumour metastasis. In this study of the aggregatory responses of human platelets to human tumour cell lines, we have found two distinct mechanisms of TCIPA. Colon carcinoma lines Colo 205 and Colo 397 produced TCIPA which was dependent upon thrombin generated through the activation of clotting factor VII, consistent with the expression of tissue factor activity by these cells.

hobo is responsible for the induction of hybrid dysgenesis by strains of Drosophila melanogaster bearing the male recombination factor 23.5MRF.

The male recombination factor 23.5MRF, isolated ten years ago from a natural Greek population of Drosophila melanogaster, has been shown to induce hybrid dysgenesis when crossed to some M strains, in a fashion slightly different from that of most P strains. Furthermore, it was recently shown that 23.

[Ceftriaxone and severe infections in medical resuscitation].

Ceftriaxone was used in 24 medical intensive care patients to treat 8 pulmonary infections, 12 septicaemias, 3 urinary tract infections, 1 meningitis. It was administered at a single intravenous dose of 2 g every 24 h. The therapy was successful, clinically and bacteriologically in 16 patients.

Regulation of lens cyclic nucleotide metabolism by Ca2+ plus calmodulin.

Adenylate cyclase activity was identified in membranes isolated from bovine lens fiber cells. Basal activity, in the presence of microM Ca2+ was stimulated by either sodium fluoride, guanosine 5'-[alpha,beta-imido]triphosphate (Gpp(NH)p), or forskolin; ethylene glycolbis(2-aminoethylether) tetraacetic acid (EGTA) markedly inhibited both the basal activity and the extent of stimulation by these agents. Exogenous calmodulin enhanced the Ca2+-dependent stimulation of adenylate cyclase activity.

Skeletal muscle sarcolemma in malignant hyperthermia: evidence for a defect in calcium regulation.

Sarcolemmal properties implicated in the skeletal muscle disorder, malignant hyperthermia (MH), were examined using sarcolemma-membrane vesicles isolated from normal and MH-susceptible (MHS) porcine skeletal muscle. MHS and normal sarcolemma did not differ in the distribution of the major proteins, cholesterol or phospholipid content, vesicle size and sidedness, (Na+ + K+)-ATPase activity, ouabain binding, or adenylate cyclase activity (total and isoproterenol sensitivity). The regulation of the initial rates of MHS and normal sarcolemmal ATP-dependent calcium transport (calcium uptake after 1 min) by Ca2+ (K1/2 = 0.

Identification of the calmodulin-binding components in canine cardiac sarcolemma.

The covalent attachment of 125I-calmodulin to canine cardiac sarcolemma has been achieved using the crosslinker dithiobis(succinimidyl propionate). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crosslinked products revealed three 125I-calmodulin-labeled components of Mr = 125,000, 108,000 and 81,000. That the formation of these three components was Ca-dependent and inhibited by unlabeled calmodulin, or calmodulin antagonists, would indicate that the formation of these components was calmodulin-specific.

Malignant hyperthermia susceptibility: cardiac histomorphometry of dogs and young and market-weight swine.

The defect causing malignant hyperthermia has been proposed to involve cardiac as well as skeletal muscle. We tested the hypothesis that histomorphometric parameters for ventricular wall from malignant hyperthermia-susceptible swine and dogs were abnormal. Hearts were obtained from: mature dogs, age- and weight-matched young swine (89 +/- 15 days, 30 +/- 3 kg); and market-weight swine (102 +/- 10 kg).

[Anorectal manometry. Practical use in a pediatric surgical clinic].

Over a series of 158 cases of anorectal manometry the authors describe the technique used in a general pediatric surgery department. Results are reported in Hirschsprung's disease specially in the neonatal period, chronic constipation, fecal incontinence after anorectal malformations and meningomyelocele, encopresis. Biofeedback was performed in 28 patients.

Enhanced Ca2+-induced calcium release by isolated sarcoplasmic reticulum vesicles from malignant hyperthermia susceptible pig muscle.

To further define the possible involvement of sarcoplasmic reticulum calcium accumulation and release in the skeletal muscle disorder malignant hyperthermia (MH), we have examined various properties of sarcoplasmic reticulum fractions isolated from normal and MH-susceptible pig muscle. A sarcoplasmic reticulum preparation enriched in vesicles derived from the terminal cisternae, was further fractionated on discontinuous sucrose density gradients (Meissner, G. (1984) J.

Behavioral fever and therapy in a rickettsia-infected Orthoptera.

Gryllus bimaculatus were infected with an intracellular prokaryote, Rickettsiella grylli, then reared either at fixed temperatures or in a temperature gradient (22-36 degrees C) where they could select the temperature they preferred. Only 50% of the infected insects reared at 28 degrees C or less survived after 20 days, against 75% of those reared at 30 degrees C or more and 90% of those in the temperature gradient. Examination of smears of insect tissue showed that all (100%) of the infected insects reared between 23 and 29 degrees C had developed a strong rickettsial infection.