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Biomedical subjects

J Thompson

Publications and source records attributed to J Thompson.

At least 739 records · Page 41Linked to original sources
PubMed1979

Group B beta-hemolytic streptococci causing pharyngitis.

Group B beta-hemolytic streptococci were isolated from the throats of 49 of 1,110 patients who had pharyngitis. Compared with patients whose throat cultures were negative for beta-hemolytic streptococci, those harboring group B were more likely to have enlarged tonsils (P less than 0.001), exudate (P less than 0.02), and tender enlarged anterior cervical lymph nodes (P less than 0.01). Group B should not necessarily be dismissed as a nonpathogen when identified in the pharynx of patients with exudative pharyngitis; laboratories which report beta-hemolytic streptococcal isolates from the pharynx only as group A or non-group A should be encouraged to perform definitive group identification of all beta-hemolytic isolates to further evaluate the role of other streptococcal groups as the causative agents for pharyngitis.

Adolescent↗
PubMed1979

Lateral wall of the olfactory fossa in determining intracranial extension of sinus carcinomas.

The role of plain skull radiography and pluridirectional tomography in determining anterior cranial fossa extension of paranasal sinus tumors is reassessed. The lateral wall of the olfactory fossa, a thin bony plate forming part of the roof of the ethmoid sinuses, is routinely visualized on plain skull radiography and pluridirectional tomography in the coronal plane and serves as an indicator of intracranial tumor extension. In a series of 47 patients with paranasal sinus tumors, 100% true positive and 3% false negative interpretations of the integrity of the lateral wall of the olfactory fossa were made with pluridirectional tomography. Interpretations with plain skull radiography were 90% true positive and 3% false negative. Assessment of the integrity of the lateral wall of the olfactory fossa by these techniques provides an accurate evaluation of the presence of intracranial tumor extension by this route. Computed tomography in the coronal plane with contrast infusion is a useful adjunct.

Adult↗
PubMed1979

Postfeeding radioimmunoassay artefact in heparinized pig plasma: studies with intestinal calcium-binding protein.

Samples of pig blood were taken in relation to feeding and assayed for intestinal CaBP by radioimmunoassay. When heparinized plasma was assayed by a double-antibody technique, significant postprandial increases of plasma immunoreactivity between twofold and 10-fold were noted. These apparent feeding responses were seen only with heparinized plasma and not with EDTA plasma, ACD plasma, or serum. Nor were such responses seen when heparinized plasma was assayed with talc or charcoal methods for phase seperation. The height of the artefactual response in immunoreactivity following feeding was related to the amount of carrier serum added during the incubation with second antibody and with the duration of this incubation. The artefact was seen in the presence of 0.01M EDTA. These results demonstrate a striking postfeeding radioimmunoassay artefact localized to the second-antibody precipitation step. The artefact can easily be avoided by several methodological changes. Such an artefact could conceivably affect other double-antibody radioimmunoassays of hormones or other substances. Caution is advised when double-antibody radioimmunoassays are used to assay samples taken in relation to feeding.

Animals↗
PubMed1978

Acute cholecystitis in the elderly: a surgical emergency.

A retrospective review of 88 male patients older than 60 years of age with billiary tract disease showed a mortality of 6.8%. More than 40% of the patients (39 of 88) had acute cholecystitis. Medical therapy failed for almost all of the patients (38 of 39) with acute inflammatory disease and they then required an operation during their initial hospitalization. In this acute disease group, 21% had empyema of the gallbladder, 18% had gangrenous cholecystitis or free perforation of the gallbladder, and 15% had subphrenic or liver abscesses. Escherichia coli and Klebsiella were obtained from 78% of the bile cultures, and obligate anaerobes were present in 25% of them. A delay in diagnosis and operation occurred in 33% of the patients with acute disease. Factors responsible for this delay included a deceptively benign clinical presentation and the requirement for prolonged resuscitation. Since response to conservative measures is unlikely in the elderly patient with acute cholecystitis, optimal management consists of resuscitation and prompt operation for control of infection.

Acute Disease↗
PubMed1978

High levels of inosine monophosphate in the erythrocytes of elasmobranchs.

The acid soluble organic phosphates of the erythrocytes of three species of elasmobranchs were assayed by chromatography on Dowex 1 anion exchange columns. Organic phosphates in the peaks eluted from these columns were identified by their ultraviolet absorption spectra and by further chromatography on paper. All three species are unusual amongst the vertebrates in that their erythrocytes contain high levels of inosine monophosphate (IMP). IMP has little effect on the oxygen affinity of the hemoglobins of the two species tested.

Animals↗
PubMed1978

Osmotic effects of membrane permeability in a marine bacterium.

When cells of Alteromonas haloplanktis 214 (ATCC 19855) were preloaded with alpha-[(14)C]aminoisobutyric acid or the K(+) in the cells was labeled with (42)K by incubation in a buffered salt solution containing 0.05 M MgSO(4), 0.01 M KCl, and 0.3 M NaCl, the cells retained their radioactivity when resuspended in the same salt solution. When NaCl was omitted from the solution, 80 to 90% of the radioactivity was lost from the cells. Cells suspended at intermediate concentrations of NaCl also lost radioactivity. New steady-state levels of the intracellular solutes were established within 15 s of suspending the cells; the percentage of radioactivity retained at each level decreased proportionately as the osmolality of the NaCl in the suspending solution decreased. With minor variations in effectiveness, MgCl(2), LiCl, and sucrose could substitute for NaCl on an equiosmolal basis for the retention of radioactivity by the cells. KCl, RbCl, and CsCl were appreciably less effective as replacements for NaCl, particularly when their osmolalities in the suspending solutions were low. The amount of alpha-[(14)C]aminoisobutyric acid taken up by the cells at the steady-state level increased to a maximum as the NaCl concentration in the suspending medium increased to 0.3 M. At suboptimal levels of NaCl, either LiCl or sucrose could substitute for NaCl in increasing the steady-state levels. The results obtained indicate that the porosity of the cytoplasmic membrane of this organism is determined by the difference between the osmotic pressure of the cytoplasm and the suspending medium. The lesser effectiveness of K(+), Rb(+), and Cs(+) than Na(+), Li, or Mg(2+) in permitting the retention of solutes by the cells is attributed to the greater penetrability of the hydrated ions of the former group through the dilated pores of a stretched cytoplasmic membrane.

Aminoisobutyric Acids↗
PubMed1978

Catabolite inhibition and sequential metabolism of sugars by Streptococcus lactis.

Growth of galactose-adapted cells of Streptococcus lactis ML(3) in a medium containing a mixture of glucose, galactose, and lactose was characterized initially by the simultaneous metabolism of glucose and lactose. Galactose was not significantly utilized until the latter sugars had been exhausted from the medium. The addition of glucose or lactose to a culture of S. lactis ML(3) growing exponentially on galactose caused immediate inhibition of galactose utilization and an increase in growth rate, concomitant with the preferential metabolism of the added sugar. Under nongrowing conditions, cells of S. lactis ML(3) grown previously on galactose metabolized the three separate sugars equally rapidly. However, cells suspended in buffer containing a mixture of glucose plus galactose or lactose plus galactose again consumed glucose or lactose preferentially. The rate of galactose metabolism was reduced by approximately 95% in the presence of the inhibitory sugar, but the maximum rate of metabolism was resumed upon exhaustion of glucose or lactose from the system. When presented with a mixture of glucose and lactose, the resting cells metabolized both sugars simultaneously. Lactose, glucose, and a non-metabolizable glucose analog (2-deoxy-d-glucose) prevented the phosphoenolpyruvate-dependent uptake of thiomethyl-beta-d-galactopyranoside (TMG), but the accumulation of TMG, like galactose metabolism, commenced immediately upon exhaustion of the metabolizable sugars from the medium. Growth of galactose-adapted cells of the lactose-defective variant S. lactis 7962 in the triple-sugar medium was characterized by the sequential metabolism of glucose, galactose, and lactose. Growth of S. lactis ML(3) and 7962 in the triple-sugar medium occurred without apparent diauxie, and for each strain the patterns of sequential sugar metabolism under growing and nongrowing conditions were identical. Fine control of the activities of preexisting enzyme systems by catabolite inhibition may afford a satisfactory explanation for the observed sequential utilization of sugars by these two organisms.

Biological Transport↗
PubMed1978

In vivo regulation of glycolysis and characterization of sugar: phosphotransferase systems in Streptococcus lactis.

Two novel procedures have been used to regulate, in vivo, the formation of phosphoenolpyruvate (PEP) from glycolysis in Streptococcus lactis ML3. In the first procedure, glucose metabolism was specifically inhibited by p-chloromercuribenzoate. Autoradiographic and enzymatic analyses showed that the cells contained glucose 6-phosphate, fructose 6-phosphate, fructose-1,6-diphosphate, and triose phosphates. Dithiothreitol reversed the p-chloromercuribenzoate inhibition, and these intermediates were rapidly and quantitatively transformed into 3- and 2-phosphoglycerates plus PEP. The three intermediates were not further metabolized and constituted the intracellular PEP potential. The second procedure simply involved starvation of the organisms. The starved cells were devoid of glucose 6-phosphate, fructose 6-phosphate, fructose- 1,6-diphosphate, and triose phosphates but contained high levels of 3- and 2-phosphoglycerates and PEP (ca. 40 mM in total). The capacity to regulate PEP formation in vivo permitted the characterization of glucose and lactose phosphotransferase systems in physiologically intact cells. Evidence has been obtained for "feed forward" activation of pyruvate kinase in vivo by phosphorylated intermediates formed before the glyceraldehyde-3-phosphate dehydrogenase reaction in the glycolytic sequence. The data suggest that pyruvate kinase (an allosteric enzyme) plays a key role in the regulation of glycolysis and phosphotransferase system functions in S. lactis ML3.

Biological Transport↗
PubMed1978

Heavy water effects on leaky heart muscle cells and actomyosin.

Heavy water inhibition of skeletal muscle contraction in barnacle and frog is thought to occur through inhibition of Ca release by SR. If this were so, D2O might be useful for studies on control of the inotropic state in mammalian myocardium. We therefore compared selected properties of mechanically disaggregated leaky myocardial fragments, and actomyosin, in D2O and H2O. At equal values of electrode-determined acidity the contraction frequency, initial velocity of 45Ca uptake, and equilibrium (Ca)i/(Ca)o of the myocardial fragments were all less when heavy water was used. For each of these parameters, and for actomyosin superprecipitation, the H2O and D2O acidity-response curves were similar but the D2O curve was shifted to the right. The actomyosin sedimentation rate was less in D2O than in H2O at near neutral acidity but not different under more acidic or basic conditions. Actomyosin ATPase showed an acidity-dependent increased activity in D2O. These results verify that heavy water inhibits contraction in mammalian myocardium, as is the case with invertebrate and frog skeletal muscle. The effect, however, cannot be attributed to inhibition of Ca release from SR.

Actomyosin↗
PubMed1977

Plasma and urinary digoxin in thyroid dysfunction.

The response to a single oral dose of 0.5 mg digoxin has been studied in eight patients, of whom four were hyperthyroid and four were hypothyroid, both before and after treatment for their thyroid dysfunction. The post-dose plasma digoxin levels were significantly lower in the hyperthyroid patients when they were thyrotoxic than when they became euthyroid. In only one hypothyroid patient was the post-dose plasma digoxin level significantly higher before treatment than it was after and in the others the digoxin values reached were either the same as, or lower than, before treatment. There was a significant correlation between the creatinine clearance and the urinary concentrations of digoxin and these both altered with change in thyroid status. Total urinary digoxin excretion did not change. Pharmacokinetic analysis suggested that digoxin was distributed in a way compatible with a two-compartment model and that the volume of the central compartment was high in thyrotoxic patients and low in hypothyroid patients. In both cases it reverted to a median value after treatment. It is recommended that plasma digoxin levels should be monitored in all patients with thyroid dysfunction who require therapeutic digoxin.

Aged↗
PubMed1977

Influenza A infections in young children. Primary natural infection and protective efficacy of live-vaccine-induced or naturally acquired immunity.

To assess the impact of an influenza A/Port Chalmers infection on normal young children, we monitored 147 children during an epidemic; 121 were seronegative. There was a high attack rate (61 of 147), and a high rate of symptomatic disease (38 of 147), which resulted in frequent physician visits (25 of 38). Influenza accounted for 76 per cent of the sick-child visits during the two-month epidemic period. Young children undergoing primary influenza infection produced hemagglutination inhibition and antineuraminidase antibodies. Because of the immunologic responsiveness of young children, we examined the serologic correlates of protection. Ten children previously infected with influenza A/London and 16 who received live, attenuated A/Hong Kong ts-1[E] vaccine were protected against infection with the non-homologous A/Port Chalmers strain. The morbidity of influenza and ability of the young child to produce protective antibody should encourage evaluation of life, attenuated influenza vaccines in this age group.

Age Factors↗
PubMed1977

Drowning and near-drowning in the Australian Capital Territory: a five-year total population study of immersion accidents.

A total population study of all serious immersion accidents is reported from the Australian Capital Territory. The annual immersion accident rate of 4-69 per 100,000 of the population at risk is low, and the fresh water fatality rate of 2-58 per 100,000 is very low. The annual fatality rate for childhood swimming pool accidents is 0-34 per 100,000 children (that is, under 16 years of age) at risk. Serious immersion accidents are not increasing in frequency, in striking contrast to the epidemic trends seen from other centres. Factors which might explain this are discussed.

Accidents↗