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Biomedical subjects

S Beer

Publications and source records attributed to S Beer.

At least 55 records · Page 3Linked to original sources
PubMed1991

The effects of human proinsulin on glucose turnover and intermediary metabolism.

We compared the effects of human proinsulin and human insulin on glucose disposal, suppression of hepatic glucose production (HGP), and intermediary carbohydrate and lipid metabolism. Six young, lean, subjects underwent eight separate euglycemic clamps with low-dose intravenous (IV) infusions of insulin and proinsulin (four each). The insulin infusions gave steady-state levels of 0.08 +/- 0.004 (I1), 0.12 +/- 0.003 (I2), 0.18 +/- 0.07 (I3), and 0.25 +/- 0.06 nmol/L (I4). The proinsulin infusions were chosen to give steady-state levels approximately 20-fold higher on a molar basis than insulin, based on previous findings that proinsulin has only 5% to 10% the biological potency of insulin. Steady-state proinsulin levels were 1.2 +/- 0.04 (P1), 2.8 +/- 0.07 (P2), 4.5 +/- 0.3 (P3), and 6.9 +/- 0.3 nmol/L (P4). HGP was suppressed equally by proinsulin and insulin at the four dose levels. Percentage elevation of glucose disposal was significantly increased during each of the insulin infusions compared with proinsulin: I1 107% +/- 4%, P1 87% +/- 4% (P = .03); I2 143% +/- 7%, P2 125% +/- 12% (P = .01); I3 238% +/- 38%, P3 173% +/- 22% (P = .03); I4 283% +/- 17%, P4 178% +/- 11% (P = .002). Dose-response curve analysis demonstrated that proinsulin stimulated glucose disposal approximately 3.3% compared with insulin. The effectiveness of proinsulin in suppressing HGP was approximately 5% compared with insulin. Plasma nonesterified fatty acids, blood glycerol, and 3-hydroxybutyrate were suppressed by similar amounts during each of the four insulin and proinsulin doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Variability in Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Small Subunits and Carboxylation Activity in Fern Gametophytes Grown under Different Light Spectra.

Two distinct ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) small subunit (SSU) populations were observed in Pteris vittata gametophytes grown under different illumination conditions. Exposure of the fern gametophytes to continuous red light (R) resulted in Rubisco SSUs that were not recognized by polyclonal antibodies raised against SSUs from spinach. Unlike the R-induced SSUs, blue light (B) induced SSUs were well recognized. This difference in SSU composition also reflected in Rubisco activity. In vitro, B-induced Rubisco exhibits a significantly higher carboxylation activity as compared to the R-induced Rubisco. Approximately a two- to threefold increase in the V(max) value of the B-induced carboxylase as compared to the R-induced one was measured. It thus seems very likely that certain domains in the SSU molecule affect enzyme activity.

Journal Article↗
PubMed1991

Utilization of Inorganic Carbon by Ulva lactuca.

Thalli discs of the marine macroalga Ulva lactuca were given inorganic carbon in the form of HCO(3) (-), and the progression of photosynthetic O(2) evolution was followed and compared with predicted O(2) evolution as based on calculated external formation of CO(2) (extracellular carbonic anhydrase was not present in this species) and its carboxylation (according to the K(m)(CO(2)) of ribulose-1,5-bisphosphate carboxylase/oxygenase), at two different pHs, assuming a photosynthetic quotient of 1. The K(m)(inorganic carbon) was some 2.5 times lower at pH 5.6 than at the natural seawater pH of 8.2, whereas V(max) was similar under the two conditions, indicating that the unnaturally low pH per se had no adverse effect on U. lactuca's photosynthetic performance. These results, therefore, could be evaluated with regard to differential CO(2) and HCO(3) (-) utilization. The photosynthetic performance observed at the lower pH largely followed that predicted, with a slight discrepancy probably reflecting a minor diffusion barrier to CO(2) uptake. At pH 8.2, however, dehydration rates were too slow to supply CO(2) for the measured photosynthetic response. Given the absence of external carbonic anhydrase activity, this finding supports the view that HCO(3) (-) transport provides higher than external concentrations of CO(2) at the ribulose-1,5-bisphosphate carboxylase/oxygenase site. Uptake of HCO(3) (-) by U. lactuca was further indicated by the effects of potential inhibitors at pH 8.2. The alleged band 3 membrane anion exchange protein inhibitor 4,4'-diisothiocyanostilbene-2,2'disulphonate reduced photosynthetic rates only when HCO(3) (-) (but not CO(2)) could be the extracellular inorganic carbon form taken up. A similar, but less drastic, HCO(3) (-)-competitive inhibition of photosynthesis was obtained with Kl and KNO(3). It is suggested that, under ambient conditions, HCO(3) (-) is transported into cells at defined sites either via facilitated diffusion or active uptake, and that such transport is the basis for elevated internal [CO(2)] at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation.

Journal Article↗
PubMed1990

Photosynthesis in Ulva fasciata: V. Evidence for an Inorganic Carbon Concentrating System, and Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase CO(2) Kinetics.

Evidence of an inorganic carbon concentrating system in a marine macroalga is provided here. Based on an O(2) technique, supported by determinations of inorganic carbon concentrations, of experimental media (as well as compensation points) using infrared gas analysis, it was found that Ulva fasciata maintained intracellular inorganic carbon levels of 2.3 to 6.0 millimolar at bulk medium concentrations ranging from 0.02 to 1.5 millimolar. Bicarbonate seemed to be the preferred carbon form taken up at all inorganic carbon levels. It was found that ribulose-1,5-bisphosphate carboxylase/oxygenase from Ulva had a K(m)(CO(2)) of 70 micromolar and saturated at about 250 micromolar CO(2). Assuming a cytoplasmic pH of 7.2 (as measured for another Ulva species, P Lundberg et al. [1988] Plant Physiol 89: 1380-1387), and given the high activity of internal carbonic anhydrase (S Beer, A Israel [1990] Plant Cell Environ [in press]) and the here measured internal inorganic carbon level, it was concluded that internal CO(2) in Ulva could, at ambient external inorganic carbon concentrations, be maintained at a high enough level to saturate ribulose-1,5-bisphosphate carboxylase/oxygenase carboxylation. It is suggested that this suppresses photorespiration and optimizes net photosynthetic production in an alga representing a large group of marine plants faced with limiting external CO(2) concentrations in nature.

Journal Article↗
PubMed1988

[Multiple sclerosis in the Bern canton (Switzerland). An epidemiologic study].

We conducted a study on the prevalence of multiple sclerosis in the canton of Berne (Switzerland) at the Department of Neurology (inpatient and outpatient sections) of the Inselspital hospital (University of Berne) in Berne. The canton of Berne is a heterogeneous region, geographically speaking, extending from the foot of the Jura mountains to high Alpine regions. There are approximately 920,000 inhabitants in an area of 6,000 square kilometers. Sources of our study were, besides the Department of Neurology of the University and the practising neurologists of Berne, the Association of Swiss Hospitals (VESKA) and the Swiss Multiple Sclerosis Society. For ensuring a safe diagnosis we employed a diagnosis score suggested by C. M. Poser et al (1983). This covered only safely established and probable cases of MS. To make sure of the actual residence of the retrospectively assessed patients we conducted a checkup with the relevant authorities. Besides personal data it was also possible, in a majority of patients, to obtain data on the onset and course of the disease. On 1, 1, 1986 1,016 MS patients were residents in the canton of Berne, according to our investigations. This corresponds to a prevalence rate of 110 MS patients for every 100.000 inhabitants. The sex ratio (female/male) is about 1.8: 1. The average age of the MS patients covered by the study was 50 years with an average duration of the disease of 18 years. From the data concerning the course of the disease our study was able to gain further pointers on the beginning of the disease, on the pattern of symptoms, course of the disease, and progression of multiple sclerosis.

Adolescent↗
PubMed1988

Heredofamilial syndrome of mesodermal hamartomas, macrocephaly, and pseudopapilledema.

A 4 1/2-year-old boy with macrocephaly, pseudopapilledema, lipoangiomatosis, macropenia, and spotted pigmentations of the glans is reported. Lipoid masses were found in the subcutaneous tissue, tonsils, and probably the left lung. Some of these findings are consistent with features already reported by Riley and Smith, later by Bannayan, and recently by Ruvalcaba et al. We propose to unify the features of this syndrome and name it macrocephaly, hamartomas, and papilledema syndrome. The inheritance in our described case seems to be autosomal dominant.

Child, Preschool↗
PubMed1987

Prodromal features of asthma.

One hundred and thirty four ambulatory children with bronchial asthma were investigated in the Pediatric Pulmonary-Allergic Service. In 95 patients an interval characterised by prodromal respiratory symptoms (cough, rhinorrhoea, and wheezing), behavioural changes (irritability, apathy, anxiety, and sleep disorders), gastrointestinal symptoms (abdominal pain and anorexia), fever, itching, skin eruptions, and toothache preceded the onset of the attack of asthma. Each child had his own constant set of prodromal findings. A significant age related increase in serum IgE concentrations was observed in these patients. No such relation was observed in children with an acute onset of attack of asthma without any preceding symptoms. We suggest that awareness of these prodromal symptoms may lead to an early introduction of treatment, thus avoiding or abbreviating some of the acute attacks of asthma.

Adolescent↗
PubMed1987

Clinical data bank at the University Department of Neurology, Bern, Switzerland: basis for an epidemiological study of multiple sclerosis in a high prevalence area.

Clinical and laboratory data for over 1000 patients with definite multiple sclerosis living on prevalence day January 1st, 1986 in the Swiss Canton of Bern, a geographically heterogeneous region, are analysed retrospectively by means of a specially developed computer system. The consequent application of the "Minimal Record of Disability" (MRD) as proposed by the IFMSS forms the basis of data sampling. Details of clinical aspects gained from these records are presented together with an account on the applicability of this system in collaborative epidemiological investigations, for which the now ongoing prospective study based on the aforementioned retrospective one at our Institution may serve as an example.

Adolescent↗
PubMed1986

Photosynthesis of Ulva sp: III. O(2) Effects, Carboxylase Activities, and the CO(2) Incorporation Pattern.

Ulva, a common green seaweed, performs at the biochemical level as a typical C(3) plant. Over 90% of label was found in glycerate 3-phosphate following a 3 second (14)C pulse in the light, and the label was subsequently transferred to sugars. Also, the level of ribulose-1,5-bisphosphate carboxylase activity in crude extracts was about 10 times higher than that of phosphoenolpyruvate carboxylase. Concerning gas exchange, photosynthetic rates of Ulva showed no O(2) sensitivity, indicating that photorespiratory CO(2) losses are repressed as in C(4) plants. This apparent anomaly could be explained by the efficient HCO(3) (-) uptake system of Ulva which might concentrate CO(2) to the chloroplasts, thus suppressing the oxygenase activity of ribulose-1,5-bisphosphate carboxylase.

Journal Article↗
PubMed1986

Predisposition of the asthmatic child to legionellosis?

The prevalence of seropositivity to Legionella spp. was studied in 184 children with bronchial asthma and in 80 control children, age- and sex-matched, without respiratory tract infections. The sera were examined by indirect immunofluorescence with antigens of six Legionella spp. The asthmatic children showed a significantly higher percentage of seroreactions to L. pneumophila than did the control children. In the asthmatic children, no association was found between age, sex, onset of asthmatic symptoms, living conditions, corticosteroid treatment, or exposure to aerosols and seropositivity to Legionella. No correlation could be found between the asthma severity score and the titer of serum antibodies to L. pneumophila. None of the 32 sera with titers of 256 or higher were reactive for Legionella-specific IgE antibodies. L. pneumophila antigen was detected in the urine of three children by an enzyme-linked immunosorbent assay (ELISA). The high prevalence of antibodies to L. pneumophila found in children with bronchial asthma, together with the detection of antigen in the urine of some of them, suggest that this group of children are highly susceptible to Legionnaires' Disease.

Adolescent↗
PubMed1985

Effects of CO(2) and O(2) on the Photosynthetic O(2) Evolution of Spirodela polyrrhiza Turions.

Net photosynthetic rates of Spirodela polyrrhiza turions, at low O(2) levels, were 6.2 and 38.8 micromoles O(2) per gram fresh weight per hour at 1 millimolar HCO(3) (-) and CO(2) saturation, respectively, and much lower in a regular low-pH growth solution. Air equilibration O(2) concentrations decreased rates considerably, except at CO(2) saturation. The surfacing rate of turions in various inorganic carbon surroundings correlated positively with their photosynthetic rates, but were the same at high and low O(2) levels. The relevance of these findings in relation to environmental conditions conductive to germination of autotrophically growing turions is discussed.

Journal Article↗
PubMed1985

Serum antibodies to Legionella agents in bronchial asthma.

The prevalence of seropositivity to Legionella species was studied in 184 children with bronchial asthma and 80 control children, age and sex matched, without respiratory tract infections. The sera were examined by indirect immunofluorescence with antigens of six Legionella species. The asthmatic children showed a significantly high percentage of seroreactions to L pneumophila compared with the control children. In the asthmatic children, no association was found between age, sex, onset of asthmatic symptoms, living conditions, corticosteroid treatment, or exposure to aerosols and seropositivity to Legionella. No relation could be found between the asthma severity score and the titre of serum antibodies to L pneumophila. None of the 32 sera with titres of 1:256 or higher were reactive for Legionella specific IgE antibodies. A high prevalence of antibodies to L pneumophila was found in children suffering bronchial asthma. Further studies are necessary to clarify the clinical relevance.

Adolescent↗
PubMed1985

A fatal case of Q fever hepatitis in a child.

A two-year-old boy of Arabic extraction presented with progressive jaundice and prolonged pyrexia. Both IgM and IgG immunofluorescent antibody titers for Q fever were 1:1280. Two goats and one cow of the domestic animals owned by the family also had positive antibody titers against Q fever. In spite of antibiotic treatment with tetracyclines and chloramphenicol, the hepatic involvement progressed gradually. On the twentieth day of admission the child succumbed from hepatic failure. This child presents a rare case of fatal hepatic failure due to Q fever.

Antibodies, Bacterial↗
PubMed1984

Bacteraemia among children in hospital--a four year prospective study.

The incidence of bacteraemia in children (excluding newborn babies) admitted to a general hospital during the period 1978 to 1981 was 3.2 patients per 1000 admissions. Of the total, nosocomial bacteraemia comprised 0.7 patients per 1000 admissions. Analysis of some probable risk factors showed that the chance of acquiring bacteraemia in the first year of life was 6.8 times that for older children, the difference being statistically significant (P less than 0.001). The male to female ratio was 1.7: but this difference was not statistically significant. Overall the case mortality rate was 4.5%. For nosocomial bacteraemia the rate was much higher (14.3%) than that of community acquired bacteraemia (1.9%) with a risk of dying 7.5 times greater (P less than 0.01). Of the pathogens isolated 71.2 per cent were Gram-negative, Escherichia coli being the most common followed by Salmonella typhi. Among the Gram-positive organisms isolated, as well as overall, the pneumococcus was the most common pathogen. Pneumonia and gastroenteritis were the underlying conditions most often found. Since the pneumococcus was the most common pathogen, and in all of our patients originated in the community, physicians who treat in out-patient clinics as well as emergency rooms should be aware of this and look especially for the early symptoms and signs of disease likely to be caused by this organism.

Adolescent↗
PubMed1982

A practical approach to the treatment of burn shock in childhood.

A simple method of evaluating and treating burn shock has been used with very good results and low mortality. The amounts of fluids given in a specific time and the type of fluids given are dependent upon the evaluation of a few simple observations. We believe that shock is a treatable condition and that 'shock kidney' is preventable. We stress the difficulty of trying to compare the results of two different burn units.

Blood Transfusion↗