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Biomedical subjects

C Berry

Publications and source records attributed to C Berry.

At least 37 records · Page 2Linked to original sources
PubMed1990

An analysis of the genes encoding the 51.4- and 41.9-kDa toxins of Bacillus sphaericus 2297 by deletion mutagenesis: the construction of fusion proteins.

A series of deletion mutants have been constructed, in which varying numbers of amino acids have been deleted from both the N- and C-termini of both the 51.4- and 41.9-kDa toxins of Bacillus sphaericus. The results show that between 34-39 and 52-54 amino acids respectively at the N- and C-termini of the 51.4-kDa protein, are not essential for toxicity. In the case of the 41.9-kDa protein, the removal of only 7 amino acids from the C-terminus abolishes toxicity whilst at least 17 amino acids can be deleted from the N-terminus without loss of toxicity. A fusion protein with the 51.4-kDa derived sequence N-terminal to the 41.9-kDa sequence yielded a protein of Mr 87 kDa which was not toxic by itself. When supplemented with cells expressing only the 51.4-kDa protein, toxicity was restored. In contrast, another fusion protein, in which the gene order was reversed, was shown to be fully active in toxicity assays.

Amino Acid Sequence↗
PubMed1990

Myocardial protection with autoperfusion during prolonged coronary artery occlusion.

Passive transcatheter coronary arterial perfusion, i.e., autoperfusion, has been introduced for clinical use to ameliorate short episodes of myocardial ischemia during percutaneous transluminal coronary angioplasty. The primary goal of this study was to evaluate the cardioprotective effect of autoperfusion after prolonged coronary artery occlusion. Accordingly, in 24 anesthetized dogs, either the left anterior descending or left circumflex coronary artery was occluded for 6 hours. The dogs were randomized to a control group subjected to coronary artery occlusion alone (n = 13) or to a group treated with transcatheter autoperfusion (n = 11). The hypoperfused zone, i.e., risk area and infarct size, were measured by autoradiography and triphenyltetrazolium chloride staining, respectively. The hypoperfused zone was 30 +/- 2% and 29 +/- 2% in the control and treated (NS) groups, respectively. When infarct size was expressed as a percent of the hypoperfused zone, it was 84 +/- 5% in the control group and 25 +/- 9% in the group treated with transcatheter autoperfusion (p less than 0.001), showing a reduction of 70%. In addition, an in vitro study showed pressure-dependent flow during autoperfusion as reflected by close linear relationship between perfusion pressure and flow (Flow = 0.54 X Pressure + 16.16, r = 0.99, n = 16). These data suggest that although passive coronary arterial perfusion for 6 hours after coronary occlusion does not prevent myocardial necrosis, it markedly reduces myocardial infarction in the canine model.

Angioplasty, Balloon, Coronary↗
PubMed1990

Prediction of salt sensitivity.

The overall prevalence of salt sensitivity was studied in 75 men stratified by diagnosis (hypertensive v normotensive) and race (black v white). All were studied in a crossover design employing a 200 mEq and 10 mEq Na/day. High salt led to a decrease in diastolic pressure for all groups (P less than .002). For systolic pressure, there was no salt effect on blood pressure across the whole group; however amongst the hypertensives, particularly the black hypertensives, high salt led to increases in systolic pressure (P less than .022). Obese patients were more likely to increase their systolic pressure in response to salt loading (P less than .05). The patients whose pressure increased on high salt were those who manifested less of a decrease in plasma levels of norepinephrine and renin in response to salt loading (both P less than .05). Systolic salt sensitivity was predicted with high statistical power (R = 0.689, P less than .00001) by a multiple regression equation employing: race; diagnosis; the change in renin and norepinephrine levels with diet; and the change in BP sensitivity to infused norepinephrine across the two diets. In view of the findings of increased norepinephrine, renin and diastolic pressure on low salt and in view of the particular physiological and epidemiological setting associated with systolic salt sensitivity, one wonders about the advisability of across-the-board recommendations of low salt diets for all hypertensive patients.

Adult↗
PubMed1990

Interaction of the Bacillus sphaericus mosquito larvicidal proteins.

Genes for 51.4- and 41.9-kDa insecticidal proteins of Bacillus sphaericus were separately cloned and expressed in Escherichia coli. Both proteins were required for toxicity. Approximately equal numbers of cells containing the 51.4- and 41.9-kDa proteins produced the greatest toxicity; excess 41.9-kDa protein did not affect toxicity, whereas excess 51.4-kDa protein reduced activity. Larvae were killed when 41.9-kDa protein was fed up to 24 h after the 51.4-kDa protein, but not when the order of feeding was reversed. Radiolabelled toxins bound in approximately equal amounts to the gastric caecum and posterior midgut of Culex quinquefasciatus larvae. Radiolabelled 51.4-kDa protein was rapidly degraded by ca. 12-13 kDa in the larval gut, while 41.9-kDa protein was degraded by 1-2 kDa. Nonreduced toxin extracted from B. sphaericus produced a band on SDS-PAGE of ca. 68-74 kDa that contained both 51.4- and 41.9-kDa proteins based on sequence analysis, and a band of ca. 51 kDa that contained primarily 41.9-kDa protein. Escherichia coli containing 51.4-kDa protein enhanced toxicity of the latter eluted SDS-PAGE band. These proteins may associate very strongly, and trace amounts of 51.4-kDa protein in preparations of 41.9-kDa protein from B. sphaericus may be responsible for the previously reported toxicity of the latter.

Amino Acid Sequence↗
PubMed1990

Effects of salt, race, and hypertension on reactivity to stressors.

Blood pressure and heart rate reactivity to a psychological stressor and to a cold pressor test were examined in a group of 51 normotensive and 37 unmedicated hypertensive men. All were studied twice, once while the participants were maintained on a moderately high salt (200 meq sodium/day) diet and once while the participants were maintained on an extremely low salt (10 meq sodium/day) diet. Dietary salt had no effect on blood pressure or heart rate responses to the two stressors. The systolic and diastolic responses of the white participants to the psychological stressor were greater than those of the black participants (both p less than 0.05); however, there was no difference between blacks and whites in reactivity to the cold pressor challenge. As compared with the normotensive group, the hypertensive group reacted to the psychological stressor with increased responses in systolic blood pressure, diastolic blood pressure, and heart rate (all p less than 0.05). The hypertensive group also hyperresponded in terms of the systolic pressure response to the cold pressor task (p less than 0.05). Plasma norepinephrine and epinephrine responses were not significantly different across the two diets, races, or diagnoses.

Adult↗
PubMed1989

Surface electrocardiogram in the detection of transmural myocardial ischemia during coronary artery occlusion.

To examine whether coronary occlusion causing transmural ischemia was accurately reflected by ST-segment elevation on routine electrocardiograms, intracoronary and surface electrocardiograms were simultaneously recorded during percutaneous transluminal coronary angioplasty (PTCA). The study group consisted of 54 patients who had intracoronary ST-segment elevation during transient coronary occlusion (left anterior descending [LAD]: 25 patients, left circumflex [LC]: 19 patients, right coronary artery: 12 patients). Elevation of the ST segment on the surface electrocardiogram (greater than or equal to 0.1 mV) was recorded in 84% of patients during LAD dilatation, in 32% of patients during LC dilatation (p less than 0.01 vs LAD and right), and in 92% of patients during right coronary dilatation (not significant vs LAD). The magnitude of intracoronary ST elevation was 1.10 +/- 0.8, 1.68 +/- 1.2 and 0.8 +/- 0.6 mV for the LAD, LC and right occlusions, respectively (not significant). Thus, despite the comparable magnitude of intracoronary ST elevation, LC occlusion resulted in ST-segment elevation on the surface electrocardiogram in significantly fewer patients than did LAD or right occlusion. During LC occlusion, 9 patients had no electrocardiographic changes and 4 had only precordial ST depression. Thus, in patients with transmural ischemia during right or LAD occlusions, concordant ST elevation on the surface electrocardiogram is common. In contrast, ST-segment elevation is an insensitive marker of LC occlusion. In patients with ongoing ischemic symptoms and isolated precordial ST depression or no repolarization abnormalities, LC occlusion should be considered in the differential diagnosis.

Adult↗
PubMed1989

Survival prediction in amyotrophic lateral sclerosis.

This longitudinal study of 194 patients with sporadic ALS demonstrated that it is possible for physicians to predict the approximate survival time for an individual ALS patient given: (1) the age of the patient, (2) the duration of his weakness and (3) an estimate of his clinical disability (ALS Score). This information is of value in the clinical management of ALS patients, and it should facilitate construction of experimental therapeutic trials in ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1989

[Caries recurrence: descriptive, analytic and prospective clinimetric study].

The purpose of the work is to study primary and recurrent caries through an epidemiological inquiry on the bucco-dental state of dental students at the University of Bordeaux II from 1986 to 1988. The first part describes the sample with mean and standard deviation; then histograms are constructed for each parameter with mean and median. A second, analytical part allows the study of the influence of time and research of risk factors and associated ones of primary and secondary caries, and evidence of a linear relationship between dental caries and quantitative factors. The last, prospective part leads to quantification of predictive value of risk factors with the calculation of sensitivity, specitivity and conditional probability. Results statistically show that risk factors predispose to dental caries and their recurrence for alpha = 10%. They, consequently, confirm particularity of the population about hygiene, treatment motivation and show trends to sugared food consumption, hygiene, salivary ph, yet setting the problem of sample representativity.

Adult↗
PubMed1988

Chloroquine treatment of severe malaria in children. Pharmacokinetics, toxicity, and new dosage recommendations.

Although empirical regimens of parenteral chloroquine have been used extensively to treat severe malaria for 40 years, recent recommendations state that parenteral chloroquine should no longer be used because of potential toxicity. We studied prospectively the pharmacokinetics and toxicity of seven chloroquine regimens in 58 Gambian children with severe chloroquine-sensitive falciparum malaria. In all regimens the total cumulative dose was 25 mg of chloroquine base per kilogram of body weight. Chloroquine was rapidly absorbed after either intramuscular or subcutaneous administration (5 mg of base per kilogram every 12 hours), producing high peak blood concentrations but transient hypotension in 5 of 18 patients (28 percent). Intermittent intravenous infusion (5 mg of base per kilogram over 4 hours, repeated every 12 hours) also produced wide fluctuations in chloroquine levels, suggesting incomplete distribution from a small central compartment. Continuous infusion (0.83 mg of base per kilogram per hour for 30 hours) and smaller, more frequent intramuscular or subcutaneous injections of chloroquine (3.5 mg of base per kilogram every 6 hours) produced smoother blood-concentration profiles with lower early peak levels and no adverse cardiovascular or neurologic effects. Chloroquine given by nasogastric tube (initial dose, 10 mg of base per kilogram) was absorbed well, even in comatose children. We conclude that simple alterations in dosage and frequency of administration can give parenteral chloroquine an acceptable therapeutic ratio and reinstate it as the treatment of choice for severe malaria in areas where chloroquine resistance is not a major problem.

Animals↗
PubMed1988

Ultrastructural studies as a method of prenatal diagnosis of neuronal ceroid-lipofuscinosis.

Ultrastructural studies of uncultured amniotic fluid cells obtained by genetic amniocentesis at 16 wk of gestation demonstrated 3 major cell types. Membrane bound curvilinear cytosomes were observed in about 30% of a subpopulation of dark, elongated cells. These are considered typical of the inclusions of the late infantile variant of neuronal ceroid-lipofuscinosis. This technique was used to monitor 6 at-risk pregnancies of which 2 were identified as affected. We have followed 6 of the 7 fetuses through to delivery with confirmation of our findings by skin biopsy in 4 and with clinical observations of a fifth child. There are major problems involved in the use of uncultured amniotic fluid cells for prenatal diagnosis. In addition to a great deal of heterogeneity of cell type, there is a considerable amount of tissue debris and a very high proportion of nonviable cells. We have examined chorionic villus tissues of 3 fetuses known to have inborn errors of lysosomal metabolism without finding any evidence of storage material. This is taken as an indication that the mutant gene(s) is not expressed in these tissues at this early stage of pregnancy. Notwithstanding these limitations, the usefulness of this technique in monitoring at-risk pregnancies has to be determined.

Amniocentesis↗
PubMed1988

Antenatal origin of neurologic damage in newborn infants. I. Preterm infants.

Currently, the diagnosis of white matter necrosis may be performed with echoencephalography when cysts are observed in the white matter adjacent to the lateral ventricles. One hundred twenty-seven infants with a gestational age less than 36 weeks (mean [+/- SE] gestational age = 31 +/- 3.2 weeks) were studied in the neonatal period with echoencephalography to determine the incidence of white matter necrosis and the perinatal variables associated with this complication. Twenty-three infants (18.3%) had white matter necrosis. Thirteen (10.3%) had cysts by day 3 (11 on day 1), indicating that the onset of white matter necrosis occurred antenatally. The incidence of antenatal white matter necrosis was inversely related to birth weight and was more frequent in infants weighing less than 1000 gm (19%). Stepwise logistic regression analysis of 31 antenatal variables showed that placental vascular anastomoses in multiple pregnancies, funisitis, and purulent amniotic fluid were the only complications associated with antenatal white matter necrosis. Follow-up neurologic evaluations were abnormal in four of six patients with antenatal white matter necrosis. The findings in this study focus attention on prenatal, rather than intrapartum and postnatal, factors as causative agents of neurologic morbidity and emphasize the importance of early and sequential evaluation of neonatal brain structures.

Cerebral Hemorrhage↗
PubMed1988

Influence of starches of low digestibility on the rat caecal microflora.

1. Male Sprague-Dawley rats were fed on either a purified, fibre-free diet or a diet in which half the maize starch was replaced with uncooked amylomaize or potato starch (equivalent to 100 or 200 g amylase-resistant starch (ARS)/kg diet respectively). Changes in short-chain fatty acids (SCFA), pH, ammonia and a number of bacterial variables in caecal contents were then assessed. 2. Both ARS supplements decreased caecal content pH by approximately 1-2 units, with an associated reduction in ammonia concentration. Potato starch significantly decreased the concentration of SCFA in the hindgut, while amylomaize supplementation increased propionic and butyric acids but decreased the occurrence of minor, branched-chain fatty acids. 3. Caecal bacterial biotransformation activities (beta-glucosidase (EC 3.2.1.21), beta-glucuronidase (EC 3.2.1.31), reduction of p-nitrobenzoic acid, apparent ammonia formation) were consistently decreased by both ARS sources. 4. The results demonstrate that amylase-resistant carbohydrate altered toxicologically important functions in the large-intestinal flora of the rat.

Ammonia↗
PubMed1987

Pharmacokinetics of rimantadine hydrochloride in patients with chronic liver disease.

Six patients with chronic liver disease and six sex-, age (+/- 5 years)-, and weight (+/- 5 kg)-matched healthy control subjects received a single dose of two 100 mg tablets rimantadine HCl. Eight additional patients with chronic liver disease who were not matched to healthy subjects received a single dose of two 100 mg tablets of rimantadine HCl. Blood and urine samples were collected and rimantadine concentrations were determined by a GCMS method. The values for maximum plasma concentration, AUC, elimination half-life, and renal clearance were not significantly different between patients and control subjects, independent of the statistical analyses (parametric and nonparametric) used. The mean apparent elimination half-life, volume of distribution, and total clearance in the matched patients with liver disease were 32 hours, 24 L/kg, and 676 ml/min, respectively. Renal clearance and the amount excreted in the urine unchanged were 63 ml/min and 10%, respectively. In conclusion, rimantadine pharmacokinetics were not appreciably altered in patients with less severe chronic liver disease.

Adamantane↗
PubMed1987

Identification, cloning and sequence analysis of the Bacillus sphaericus 1593 41.9 kD larvicidal toxin gene.

A number of strains of the widespread aerobic soil bacterium, Bacillus sphaericus, possess crystalline inclusions of a toxin lethal to a variety of insect (larvae) which are vectors of major tropical diseases. Partial amino acid sequence data from one strain, B. sphaericus 2362 have permitted us to design oligonucleotide probes for identifying the toxin gene in the closely related B. sphaericus 1593. The gene was found to be contained within an EcoRI-HindIII fragment and was cloned in its entirety in the bacterial plasmid pUC12. The DNA sequence was determined together with the upstream and downstream controlling elements, and a sequence of 370 amino acids was deduced for the toxin protein. This is the first reported sequence of a B. sphaericus toxin gene and will facilitate further work in characterizing the genes from other strains of different virulence and host range. The data do not support the suggestion that the toxin is derived by proteolysis of a protoxin precursor.

Amino Acid Sequence↗
PubMed1987

Diminished atherosclerotic arterial calcifications in asthma. A possible role for elevated endogenous heparin-like material.

Twenty-seven patients beyond the age of 50 were radiographically compared with age- and sex-matched controls for the degree of calcified atherosclerotic plaque formation in the aorta and its major pelvic branches. Significantly less calcification was present in the aorta, iliac and hypogastric arteries of the asthmatics (P = 0.01). Previous studies in other asthmatic patients have shown elevated endogenous heparin-like material to be present in their plasma. It is speculated that diminished atherosclerosis in asthmatic patients might be a consequence of elevated circulating endogenous heparin-like material.

Aged↗