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Biomedical subjects

E Weiss

Publications and source records attributed to E Weiss.

At least 217 records · Page 12Linked to original sources
PubMed1981

Effect of chronic and acute changes in sodium balance on the urinary excretion of prostaglandins E2 and F2 alpha in normal man.

1. The effects of changes in sodium balance on renal prostaglandins have been hitherto studied mainly in experimental animals and the results have been controversial. In this study the 24 h urinary excretion of prostaglandins E2 and F2 alpha was measured by radioimmunoassay in seven normal subjects under basal conditions and after 5 days of a diet containing less than 20 mmol of sodium/day. Subsequently a sodium chloride (150 mmol/l: saline) load (300 mmol of sodium over 4 h) was infused and prostaglandins were again measured in hourly urine collections. Plasma renin activity and aldosterone were also measured under basal conditions, after the low sodium diet and at 2 and 4 h of the saline infusion. 2. Dietary sodium restriction was associated with a marked increase in prostaglandin E2 excretion (from 769.7 +/- 201.6 SEM to 1761.3 +/- 304.9 ng/24 h, P less than 0.0005). Prostaglandin F2 alpha also increased from 1187.0 +/- 390.1 to 1435.6 +/- 344.6 ng/24 h, but this was not statistically significant. The prostaglandin E2/prostaglandin F2 alpha ratio increased from 0.83 +/- 0.2 to 1.52 +/- 0.34 (P less than 0.01). Plasma renin activity and aldosterone rose significantly (P less than 0.05 and less than 0.0025 respectively). 3. During the saline load prostaglandin E2 decreased after 2 h from 142.4 +/- 29.9 to 86.7 +/- 22.9 ng/h (P less than 0.05) and to 36.9 +/- 5.96 ng/h after 4 h. Prostaglandin F2 alpha decreased at a slower rate, from 98.4 +/- 18.7 to 37.5 +/- 8.8 ng/h at 4 h (P less than 0.02). At 4 h the prostaglandin E2/prostaglandin F2 alpha ratio returned to control values (0.90 +/- 0.17). Plasma renin activity and aldosterone decreased significantly after 2 h (P less than 0.02 and less than 0.0025 respectively) and reached control values after 4 h. 4. The present study demonstrates that chronic and acute changes in sodium balance induce changes in the excretion of prostaglandin E2 parallel to changes in plasma renin activity and aldosterone. The similar but quantitatively smaller changes in prostaglandin F2 alpha and the inversion of the ratio between the two prostaglandins during sodium deprivation suggest that at least two factors are involved: increased delivery of substrate for prostaglandin synthase and decreased activity of the prostaglandin E1 9-keto-reductase. Prostaglandins probably play an important role in the adaptation of the kidney to changes in sodium balance.

Adult↗
PubMed1981

Improved serodiagnosis of Salmonella enteric fevers by an enzyme-linked immunosorbent assay.

The value of the enzyme-linked immunosorbent assay (ELISA) for the serological diagnosis of typhoid or paratyphoid fevers was tested with a collection of five sets of sera from 23 individuals who had no history of Salmonella infection from a nonendemic area (set 1) and from 143 patients from a highly endemic area (sets 2 to 5). The test was performed with a crude cell envelope fraction derived from Salmonella typhi. On the basis of results with sera in set 1, titers >160 (inverse of serum dilution) for immunoglobulin M (IgM) or >500 for IgG were regarded as signifying a specific antibody response. These titers were occasionally exceeded in sera in set 2, derived from patients with no clinical or laboratory evidence of Salmonella infection. In presumptive cases of typhoid or paratyphoid fevers (culture positive and agglutination negative or vice versa; 13 patients, set 3, and 26 patients, set 4, respectively), IgG antibodies were encountered more frequently than IgM, but some sera were negative in each group. In 81 confirmed cases (culture and agglutination positive, set 5) IgG antibodies were detected in at least one of the paired sera from all patients, and the IgG titers were higher (median 3,500) than those of the IgM antibodies (median 600). There was no evidence of a significant difference in IgM or IgG titers between acute- and convalescent-phase sera. The titers of 10 paired sera from patients from whom S. enteritidis, bioserotype paratyphi A, was isolated were somewhat lower than those of 84 patients with S. typhi isolation (serogroup D). There was some correlation between O antigen agglutination and IgM enzyme-linked immunosorbent assay, but otherwise the titers in the two serological tests varied independently. Of 11 patients in set 3 (2 patients with serogroup B agglutinins omitted), 1 belonged to blood group O, in contrast to 54 group O among 107 agglutination-positive patients, a distribution not necessarily reflected by the enzyme-linked immuno-sorbent assay. This study has provided good evidence that the enzyme-linked immunosorbent assay can serve as a valuable aid to the diagnosis of Salmonella infection in an endemic area, as a substitute for the agglutination test.

ABO Blood-Group System↗
PubMed1981

Intake follow-up of "no service" cases.

At The Hospital for Sick Children in Toronto, an attempt was made to bypass long pre-assessment waiting lists by referring an increasing number of patients to local community resources at the point of the initial intake call. During the pilot study, we contacted 40 families who had been redirected along these lines between January and June 1979. We found that 31 (78%) families had followed our recommendation and most were satisfied with the treatment they were receiving. This suggests that "re-referral" upon intake can often be a highly effective and useful service when provided by a central resource and consultation centre. A further systematic follow-up of all applications to children's mental health clinics, including a careful appraisal of no-show cases (families who are accepted so that we can tailor our services to the specific child psychiatry needs of our varied clientel.

Adolescent↗
PubMed1980

The not-so-benign Miller Fisher syndrome: a variant of the Guilain-Barré syndrome.

Two patients with Fisher's syndrome of ophthalmoplegia, ataxia, and areflexia experienced severe weakness and respiratory distress. Both patients required tracheostomy and assisted ventilation, but both made a complete recovery. Fisher's syndrome is generally considered to be a benign variant of acute infectious polyneuropathy (the Guillain-Barre syndrome). Our two patients demonstrate that the condition is not always benign.

Adult↗
PubMed1980

Significance of bursa of Fabricius as target organ in infectious bursal disease of chickens.

The highly virulent strain Cu-1 of infectious bursal disease virus caused 100% mortality in 4-week-old specific pathogen-free chickens. In contrast, chickens infected after bursectomy did not become sick and only showed some discrete and transient necrosis in lymphatic tissues. However, these chickens contained infectious virus and, subsequently, produced specific antibodies. The virus concentrations in the organs studied reached their maximum 2 days postinfection, but were about 1,000 times lower in non-bursectomized animals. It may be assumed that in bursectomized chickens the early events of infection are the same as in non-bursectomized ones. Virus is spread in varius organs, but due to the absence of a sufficient number of susceptible cells, virus multiplication is moderate and can be kept in check by the host defense mechanism. With the occurrence of circulating specific antibodies the virus can be rapidly eliminated. The studies particularly stress that the availability of a large number of highly susceptible cells is a crucial point in acute viral infections.

Animals↗
PubMed1980

[Vagus effect on action potentials of rest-potentiated contractions in the isolated left atrium of the rabbit].

After a period of rest action potentials in constantly driven preparations of left rabbit atria show a marked change in configuration. After the upstroke an early repolarization takes place which is followed by a prolonged phase of secondary depolarization. This depolarization is strongly suppressed by vagal stimulation. Frequency-response characteristics of this electrotropic effect were obtained by stimulating the vagal supply of the preparation with frequencies in the range from 1.0 to 40.0 s-1 and compared with those of the constantly driven preparation. In most cases studied the frequency-response curves for the post rest action potential are steeper in rise and shifted to the left. By placing a series of vagal stimulations at different moments into the resting interval vagal effects could be composed to reflect the time course of transmitter action in a non beating preparation. It was shown that such time course is not essentially altered compared with that of a driven preparation. From a mathematical treatment of the frequency-response relations it is concluded that post rest action potentials show a higher sensitivity towards the transmitter action and that the amount of transmitter liberated after a period of rest may be increased. Possible explanations for this behaviour are proposed.

Action Potentials↗
PubMed1979

Demonstration of specific antibodies to a coxsackie-like virus in patients of a hepatitis outbreak.

Lynchburg fecal virus (LFV), originally isolated from the stool of an infectious hepatitis patient, was passaged 15 times in WI-38 cells and partially characterized. Its properties are as follows: RNA virus; 27 nm in diameter, picornavirus-like morphology; inactivated at 56 C for 60 minutes; resistant to treatment with hydrochloric acid (pH 3.0), chloroform (33%), and diethyl ether (20%). Neutralization studies indicated that LFV is antigenically related to coxsackievirus A-24 but not to prototype hepatitis A virus (HAV). The simultaneous occurrence of infections with LFV and with HAV was indicated by the results of enzyme immunoassay (EIA) of the sera of patients of the Lynchburg outbreak. Absence of anti-LFV in patient sera was accompanied by an absence of anti-HAV and, conversely, an increased titer in anti-LFV was accompanied by an increased titer in anti-HAV. Each antibody type was shown to be elicited independently indicating simultaneous infections with LFV and HAV. The contribution, if any, of LFV to disease in the outbreak remains unknown.

Antibodies, Viral↗
PubMed1979

Growth of Rickettsia typhi in irradiated L cells enhanced by lysosomal stabilization.

The growth of some obligate intracellular parasites is contingent upon avoidance of lysosomal activation during growth in their host cells. This is accomplished by the various parasites by different mechanisms and with different degrees of efficiency. The possibility was tested that the lysosomal stabilizer cortisone acetate might protect and thus enhance the growth of Rickettsia typhi in mouse L cells irradiated 6 days earlier. Beginning 2 days before infection of the L cells with a multiplicity of 10 rickettsiae, 20 microgram of cortisone per ml was added in medium 199 containing 5% fetal calf serum. This concentration of cortisone was below the cytotoxic level, as determined by viability staining, but was sufficient to significantly alter the ratios of cellular and released acid phosphatase and beta-glucuronidase in uninfected and infected cells, as shown by spectrophotometric analysis. Rickettsial replication, measured by hemolytic activity at 96 h and confirmed by microscopic observations at earlier stages of infection, was increased by the cortisone. Cortisone concentrations of 10 or 40 microgram/ml were less effective, and cortisone was ineffective when the rickettsial multiplicity per L cell was 2 or lower. These results indicate that amounts of cortisone that increase lysosomal stabilization in L cells favor rickettsial multiplication when the multiplicity of infection is relatively high.

Alkaline Phosphatase↗