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Biomedical subjects

R Mueller

Publications and source records attributed to R Mueller.

At least 109 records · Page 6Linked to original sources
PubMed1986

T3 releasing activity by Graves' sera from Graves' thyroid in vitro.

The insensitivity of Graves' thyroid to stimulation of cAMP formation by TSH as well as Graves' immunoglobulins in vitro is well known. The present study was performed to find out Graves' sera which may induce a final activation i.e. stimulation of T3 release in Graves' thyroid slices despite this insensitivity of tissue and to characterize determinants responsible for the efficiency of those sera. Out of 20 sera from patients with active untreated Graves' disease 6 were found to stimulate T3 release from Graves' thyroid in vitro. These 6 sera were effective in stimulating different Graves' glands, irrespective of pretreatment with propranolol, thiamazole (methimazole) or thiamazole plus iodine. In contrast, a significant response to bTSH was not observed in any Graves' gland. For comparison, 17/20 of the same sera were able to stimulate T3 release when tested on human goitrous thyroid. Sera which stimulated Graves' slices revealed no higher stimulating activities in goitrous tissue than serum samples which did not. All sera were additionally assessed for TSH binding inhibiting immunoglobulins in a radioreceptor assay. Remarkably, Graves' thyroid stimulating sera had a low or absent TSH binding inhibiting activity. Thus, hormone release from Graves' thyroid in vitro - in contrast to that from goitrous tissue - could only be activated by a minority of Graves' sera. These Graves' thyroid stimulating sera could be characterized to contain a selected spectrum of biologically active antibodies with a high TSH agonistic potency stimulating in the presence of a negligible TSH binding inhibiting activity.

Adult↗
PubMed1985

On the therapy of disturbances of blood fluidity.

Physiology and pathophysiology of blood fluidity are reviewed focussing the clinical relevance of the different hyperviscosity syndromes with particular respect to the microcirculation and thromboembolic complications. A new therapeutical approach is presented with pentoxifylline, a drug which largely satisfies the complex requirements of a compound affecting most of the determinants of disturbed blood fluidity. The presented data of the multifunctional pharmacological properties of pentoxifylline on blood components and vessel wall suggest this drug as indicated for the treatment of the disorders of blood fluidity linked with many diseases. Its antihemostasiological and antithrombotic potential also offers the facility for prevention of postoperative thrombotic events and in vessel surgery to avoid reocclusion.

Blood Coagulation↗
PubMed1984

Role of prostaglandins in pathogenesis of bovine mastitis induced by Escherichia coli endotoxin.

Four doses (5 to 100 micrograms, 1 dose/quarter) of Escherichia coli endotoxin were introduced into lactating mammary glands of 2 cows. There was no effect on milk prostaglandin (PG) E2 concentration, except that the concentration was increased from 200 pg/ml of milk to 1,060 pg/ml at post-treatment hour (PTH) 8 in cow 1 and from 75 to 420 pg/ml at PTH 4 in cow 2 after the highest dose 100 micrograms. Endotoxin caused a dose-dependent increase in milk PGF2 alpha concentrations in both cows. After the highest dose, PGF2 alpha was maximally increased from 200 to 3,500 pg/ml at PTH 4 in cow 1 and from 250 to 2,000 pg/ml in cow 2 at PTH 8. The instillation of 50 micrograms of endotoxin in all 8 quarters of 2 more lactating cows caused no significant (P greater than 0.05) changes in milk PGE2 and thromboxane B2 concentrations, whereas milk PGF2 alpha was significantly increased from the base-line value of 642 to 2,683, 1,189, and 2,281 pg/ml at PTH 4, 8, and 12, respectively. The 6-keto-PGF1 alpha was also significantly increased from the base-line value of 305 to 871, 631, and 600 pg/ml at the corresponding times, respectively. A marked increase in vascular permeability, as judged by high concentrations of serum albumin in the whey, was observed as early as PTH 4 and peaked at PTH 12 followed by a gradual decline, although it remained significantly increased over the control for 48 hours after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Histology of congenital nevi during the first year of life. A study by conventional and electron microscopy.

We studied 14 biopsies of congenital melanocytic nevi of children up to 1 year of age. In 11 biopsies we found two different types of melanocytic cells. In the reticular dermis, they were small cells. They had small nuclei, little cytoplasm, and no detectable pigment. They did not come in nests, but were scattered between the collagen bundles. The other type of cells was found within the epidermis or closely under it. These cells were large and round, and had abundant cytoplasms and evenly distributed melanin. Sometimes these cells were arranged in nests and in two moles they were also found in the epithelia of follicles. In all of these biopsies (with three exceptions) the superficial, large pigmented cells were separated from the deep, small, nonpigmented ones by a zone of tissue without any melanocytic cell. Early in life both types of cells are clearly separated, and the superficial ones are few. At later ages the superficial large cells are found in increased numbers, whereas the number of the deep ones does not change with age.

Biopsy↗
PubMed1983

Restriction endonuclease mapping of gamma-delta-beta-globin region in G gamma (beta)+ HPFH and a Chinese A gamma HPFH variant.

Restriction endonuclease mapping of the beta-globin genomic region was used for studying the molecular basis of two variants of hereditary persistence of fetal hemoglobin (HPFH): an African G gamma (beta)+ HPFH and a Chinese HPFH variant with predominant synthesis of A gamma chains. HPFH and control DNA samples were digested with a battery of restriction enzymes, and the fragments were identified by hybridization to a family of discrete probes. DNA fragments from the A gamma HPFH (Chinese) and the G gamma (beta)+ HPFH individuals were identical with those of the normal controls. These findings suggest that the two mutants are the result of small structural anomalies of DNA sequences that play a role in the regulation of the expression of gamma-globin genes.

Chromosome Mapping↗
PubMed1983

Comparison of hemagglutination and competitive enzyme-linked immunosorbent assay procedures for detecting canine parvovirus in feces.

A competitive enzyme-linked immunosorbent assay (ELISA) for detection of canine parvovirus (CPV) antigen in fecal samples was developed. Fecal samples were tested by ELISA and a direct hemagglutination assay, and the results compared. The tests gave the same results in 83% and 88% of the fecal samples, depending on whether the samples were treated with chloroform. The discrepancies were due to the fact that each test detected virus in certain fecal samples that was not detected by the other. The use of a monoclonal anti-CPV conjugate resulted in a highly specific test. The performance of the ELISA as a competitive assay also increased the reproducibility and sensitivity over that which could be obtained from a classic sandwich-type procedure.

Animals↗
PubMed1983

Hemolytic complement titers and complement C3 levels in endotoxin-induced mastitis.

Escherichia coli lipopolysaccharide B was instilled through the lactiferous duct of cows to induce acute mastitis. Hemolytic complement (C) activity and C3 concentrations were determined in blood serum and in renninprecipitated whey before, and at certain times after, mastitis was induced. Hemolytic complement activity was detected in the whey only during the first 36 hours after endotoxin was instilled, whereas activity was not seen before and 48 or more hours after the endotoxin was given. The maximum titer as measured with the guinea pig RBC/bovine natural antibody system was 1:64. The C3 concentrations in normal whey (before installation of endotoxin), measured by radial immunodiffusion, were between 1% and 4% of the base-line blood serum values (pool from healthy cows). The whey concentration of C3 increased (to 5% to 18%) during the first 8 hours of mastitis. However, at 72 hours, the whey values were back to preinstillation concentrations in all quarters.

Animals↗
PubMed1983

Changes of complement values in calves during the first month of life.

Hemolytic complement activity and the 3rd component of complement (C3) concentrations were measured in the blood sera of 8 dams before, at, and after parturition, and in the sera of their calves before and after feeding colostrum and at fixed intervals up to 1 month of life. The mean hemolytic titer in the dams, as measured by incubating guinea pig RBC sensitized with bovine natural antibodies in serially diluted serum, was slightly less than 200 and was not influenced by parturition and onset of lactation. The titers in the sera of the calves immediately after birth ranged from 63 to 149 with a mean of 99. One day later, values in all calves had dropped markedly to a mean of 39. During the following month, the titers increased and reached the precolostral levels after about 4 weeks; however, these titers were still far below the titers measured in adult cows. A similar pattern was seen in the C3 concentration. The mean value at birth was 28% of the values measured in adult cows. Values decreased to 18% one day later and increased during the following month to 43% of the adult C3 concentration.

Aging↗
PubMed1982

Effects of acute potassium infusions with salts other than chloride on plasma renin activity.

To evaluate the contribution of chloride to the suppression of plasma renin activity (PRA) by KCl, PRA was measured before and after venous infusions of KCl, KHCO3, KNO3, and KC2H3O2 in dietary NaCl-restricted rats. In contrast to controls, PRA decreased (P less than 0.02) after infusion of each potassium salt [KCl from 55.3 +/- 6.4 to 27.0 +/- 6.4 ng.ml-1.h-1 (mean +/- SE); KC2H3O2 from 39.3 +/- 4.0 to 20.6 +/- 4.0; KHCO3 from 64.4 +/- 6.2 to 47.2 +/- 6.2; KNO3 from 40.0 +/- 4.0 to 18.6 +/- 4.0]. Arterial pressure, plasma volume, inulin clearance, serum sodium concentration, and net sodium balance were not different between control and potassium-infused groups. Potassium loading did not increase absolute or fractional sodium excretion. PRA failed to decrease in animals given an equal volume of NaNO3. Furosemide prevented the fall in PRA associated with potassium loading despite replacement of urinary losses. These results suggest that the decrease in PRA observed during potassium loading occurs through the macula densa mechanism but is not dependent on concomitant chloride administration. As furosemide prevents the fall in PRA, macula densa chloride transport may be necessary for potassium to exert this effect.

Animals↗
PubMed1982

Chemotactic factors for bovine leukocytes.

An agarose method was used to determine the nature of chemotaxins for bovine leukocytes as related to coliform mastitis. Freshly collected bovine serum or plasma was frequently chemotactic, probably due to spontaneous complement activation. Fresh serum was always rendered chemotactic when activated with zymosan or when heat-killed or viable coliform bacteria were incubated in the serum. The bacteria did not contribute to preexisting activity in the serum. Escherichia coli grown in synthetic media did not generate chemotaxins, and the synthetic peptide formyl-L-methionyl-L-leucyl-L-phenyl-alanine was not chemotactic in the agarose system for bovine leukocytes. Endotoxin-treated serum had variable activity.

Animals↗
PubMed1981

Enzyme-linked immunosorbent assay for the quantitation of immunoglobulin G bound to Escherichia coli.

Two strains of Escherichia coli were opsonized by incubation in heat-inactivated bovine blood serum and in whey. The opsonized bacteria were then immobilized by complexing with anti-bovine antibodies previously coated to walls of polystyrene tubes. The amount of bovine immunoglobulin (Ig) G in the immobilized complex was then determined by a direct enzyme-linked immunosorbent assay, using peroxidase as enzyme. Thus, a direct measurement of one class of opsonic substances on the surface of the organisms was determined. The sensitivity for measurement of IgG ranged from nanograms to micrograms. After incubation in blood serum, 500-fold more IgG was found on the surface of the serum-resistant strain. The amount of IgG absorbed from whey in each instance was much less than that absorbed from serum. The number of bound molecules per bacterium ranged between 2,000 and 2,000,000, depending on both the strain and the serum.

Animals↗
PubMed1976

Thyrotropin releasing hormone: antagonism of pentobarbital narcosis in the monkey.

The effect of TRH on pentobarbital narcosis in 21 rhesus monkeys was examined. Vital signs monitored included respiration rate, heart rate, temperature, sleeping time,and time of reappearance of certain reflexes. Blood samples were obtained for pentobarbital assay. Two dose schedules for TRH administration were used. One group of 6 animals received a single dose of 20 mg/kg 30 min after barbiturate administration, while the other group were received 3 injections of 20 mg/kg spaced at 30, 40 and 50 min after injection of pentobarbital. Both groups were sex balanced. TRH administration resulted in dramatically increased respiration and heart rates and arrested the progress of barbiturate induced hypothermia. The extended dose schedule prolonged increased respiration rate and a differential effect of TRH on pentobarbital induced hypothermia across sexes was observed. All animals regained reflexes sooner and sleeping time was reduced by 22%. No differences in pentobarbital blood levels with TRH were observed. These results extend earlier work in rodents to primates and suggest a possible use of TRH in cases of acute barbiturate intoxication.

Animals↗