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Biomedical subjects

J Hess

Publications and source records attributed to J Hess.

At least 253 records · Page 14Linked to original sources
PubMed1985

Blood-brain barrier and peptides.

The brain is both the source and the recipient of peptide signals. The question is: Do endogenous, blood-borne peptide molecules influence brain function? Brain regions with the tight capillaries of the blood-brain barrier (BBB) extract low but measurable amounts of labeled peptide molecules from an intracarotid bolus injection. In the rat, the extraction fractions of beta-casomorphin-5, DesGlyNH2-arginine-vasopressin, arginine-vasopressin, lysine-vasopressin, oxytocin, gonadoliberin, substance P, and beta-endorphin, studied in this laboratory, range from 0.5% (substance P) to 2.4% (arginine-vasopressin). Extraction varies little among the 15 examined brain regions. As shown for arginine-vasopressin, the extracted peptides may be bound in part to specific binding sites located on the luminal membrane of the tight endothelial cells. Transport of peptide molecules across the BBB cannot be ruled out, but it is unlikely that endogenous peptides pass the BBB in physiologically significant amounts. In contrast, in brain regions with leaky capillaries, e.g., selected circumventricular organs including the pineal gland, neurohypophysis, and choroid plexus, the peptide fraction extracted approaches that of water. Within the circumventricular organs, the peptide molecules actually reach the cellular elements of the tissue. However, no studies definitively show that peptides reach neurons in the deeper layers of the brain. On the other hand, blood-borne peptides influence the BBB permeability by altering the transport of essential substances. The effect may be mediated by specific peptide binding sites located at the luminal membrane of the endothelium. It is possible that the effect of peptides on the BBB is necessary for proper brain function.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Left ventricle descending aorta valved conduit to relieve congenital aortic stenosis in children.

A valved conduit was inserted between the apex of the left ventricle and the descending aorta in 2 patients, 4 months and 10 years of age, respectively, who had valvular aortic stenosis. The development of both patients has been excellent since operation. At control catheterization (1 and 2 years postoperatively) no pressure gradient was found between the left ventricle and the aorta. In both patients the aortic valve area showed growth to near normal size on echocardiographic study 3 years postoperatively.

Aorta, Thoracic↗
PubMed1984

Lack of neutralizing antibodies to caprine arthritis-encephalitis lentivirus in persistently infected goats can be overcome by immunization with inactivated Mycobacterium tuberculosis.

The pathogenesis of the persistent progressive diseases of sheep (visna-maedi) and goats (arthritis-encephalitis) is dependent on continuous replication of the causative lentiviruses. One subgroup of these viruses, Icelandic visna virus, accomplishes this form of replication by undergoing antigenic mutation. Mutant viruses arising late in the infection escape neutralization by antibodies directed to the parental virus. In contrast, we show here that viruses obtained from persistently infected sheep and goats with natural disease in this country do not induce virus-neutralizing antibodies, although antibodies to virus core proteins were produced. The lack of neutralizing antibodies was not overcome by hyperimmunization of animals with concentrated preparations of live or inactivated virus. Thus, failure to produce these specific antibodies was not due to lack of sufficient antigen or interference with the immune response because of the ability of these viruses to infect macrophages. The hyporesponsive state, however, was overcome by immunization of animals with virus and large amounts of inactivated Mycobacterium tuberculosis. Induction of agglutinating and neutralizing antibodies by this method was probably due to a unique form of antigen processing by macrophages activated by M. tuberculosis. Neutralizing antibodies were produced for the first time against the caprine arthritis-encephalitis virus by this method. These antibodies have similar biological properties to those induced by Icelandic visna virus. They belong to the immunoglobulin G1 subclass, they are effective against a narrow range of caprine arthritis-encephalitis viruses, and they identify (for the first time) antigenic variants among these caprine agents.

Animal Diseases↗
PubMed1984

Generalised Coxsackie A9 infection in a neonate presenting with pericarditis.

Coxsackie A9 virus was isolated from a neonate presenting with a massive pericardial effusion. Delivery had occurred after maternal infection. The virus was cultured from the cerebrospinal fluid, urine, and faeces of the infant and from the faeces of the mother and a sibling. Despite signs of generalised infection with pericarditis, meningitis, pneumonitis, and hepatitis, recovery was complete.

Adult↗
PubMed1984

[Myocardial infarct in a newborn infant].

Myocardial infarction is rarely described in the newborn. We report a case in which the newborn had a normal heart and probably normal coronary arteries. The only presenting sign was transient extrasystolic beats. The course was uneventful and our patient recovered spontaneously. A review of the literature is presented.

Cardiac Complexes, Premature↗
PubMed1984

Protein-losing enteropathy after Fontan operation.

Generalized edema resulting from severe protein-losing enteropathy occurred in three patients 12, 15, and 17 months after the Fontan operation. One patient originally had tricuspid atresia and the other two, univentricular heart disease. At operation a conduit had been inserted between the right atrium and pulmonary artery. Apart from the protein loss, the patients were in good health. The cardiac catheterization data obtained 0.8 to 2.4 years (median 1.3 years) after operation in the three patients with protein-losing enteropathy were compared with those of 18 patients in whom Fontan's operation had been performed because of tricuspid atresia (eight patients) or univentricular heart disease (10 patients). All had atriopulmonary connections. The mean right and left atrial pressures and systemic blood flows measured by dye dilution in the patients with and without protein-losing enteropathy did not differ. However, the patients with protein-losing enteropathy had a higher diastolic right atrial pressure. Since maximal antegrade flow in the superior vena cava after Fontan's operation occurs during atrial diastole, these observations suggest that an increase in diastolic right atrial pressure may result in protein-losing enteropathy because of impairment of blood flow and therefore congestion in the superior vena cava, subclavian vein, and thoracic duct.

Adolescent↗
PubMed1984

[Biocompatibility of implants with and without fluorohydrocarbon glow-discharge polymer coating. 1. Histologic and semiquantitative estimation of subcutaneous reactions in guinea pigs].

The reaction of the subcutaneous tissue in guinea-pigs at implants of titanium, titanium/glow discharge polymer, Gisadent KCM (chromium cobalt molybdenum alloy), and Gisadent/glow discharge polymer was investigated by a semiquantitative method of informing character. The 4 tested materials were well-tolerated at which titanium caused the smallest reaction.

Animals↗
PubMed1984

[Biocompatibility of implants with and without fluorohydrocarbon glow-discharge polymer coating. 2. Automated equidensitometric recording of tissue reactions].

A conclusion on the biocompatibility, the solubility, and the chronic toxicity of different implant materials showed the equidensitometric measurement of the capsular thickness in the environs of the implants by means of the electronic image interpretation equipment Densitron. The method, the results, and the advantages of the technique are described.

Animals↗
PubMed1984

[Biocompatibility of implants with and without fluorohydrocarbon glow-discharge polymer coating. 3. Mathematical models of the subsiding processes of the tissue reaction].

The subsidence process of the tissue reaction was estimated by the thickness of the fibrous capsule as well as different histologic characteristics in dependence on the period after the implantation of 4 several implant materials. This subsidence process was fitted mathematically by an exponential function respectively a power function by means of the regression analysis. The power function described best the experimentally found curve. The correspondence, on principle, of the subsidence process of the fibrous capsula thickness on the one hand and the 9 histologic characteristics on the other hand could be proved. A standard valuation for subcutaneous tests is demanded which include the designation of the thickness of the fibrous capsula as well as characteristic cell type frequencies as histologic characteristics.

Animals↗
PubMed1983

Penicillin prophylaxis in children with cardiac disease: postextraction bacteremia and penicillin-resistant strains of viridans streptococci.

The incidence of postextraction bacteremia in 82 children with dental foci and cardiac disease given parenteral penicillin prophylaxis was assessed 5 min after extraction. Penicillin concentrations were determined in blood samples obtained at the same time. Before extraction, cultures were taken from the gingival sulcus. Postextraction bacteremia occurred in 21% of the patients and was due to penicillin-sensitive microorganisms in 10 and to both penicillin-sensitive and penicillin-resistant microorganisms in seven children. In three of these children penicillin-resistant viridans streptococcal strains were isolated. Penicillin-resistant viridans streptococci were present in the gingival sulcus flora of 39% of the children, but a relationship between the presence of such strains in the gingival sulcus and the occurrence of postextraction bacteremia could not be demonstrated. There was no difference in the serum penicillin concentrations found in children with bacteremia due to penicillin-sensitive or penicillin-resistant microorganisms, or between the concentrations in children with and without bacteremia.

Adolescent↗
PubMed1983

Significance of penicillin tolerance in vivo: prevention of experimental Streptococcus sanguis endocarditis.

To determine whether in-vitro tolerance to penicillin among viridans streptococci influences the efficacy of penicillin in vivo, we studied four strains of dextran-producing. Streptococcus sanguis serotype II. All four strains were inhibited in vitro by 0.1 mg/l penicillin or less; one was not-tolerant, one intermediate, and two were tolerant to the lethal action of penicillin. The combination of penicillin and streptomycin killed all strains completely within 24 h in vitro. Sera from rabbits injected with penicillin were inhibitory for all strains, but were bactericidal only for the non-tolerant strain. The incidence of endocarditis in untreated rabbits with left heart catheters was 100% after inoculation of each of the four strains. Despite attempted prophylaxis with procaine penicillin G, endocarditis developed in 44 of 70 rabbits (63%) injected with the tolerant strains, contrasting with 2 of 22 (9%) for the non-tolerant strain (P=0.0001). The probability that penicillin would fail to prevent endocarditis was directly related to its minimal bactericidal concentration for each strain (r=0.95). In contrast, the combination of penicillin plus streptomycin always prevented endocarditis. We conclude that penicillin tolerance can be a crucial determinant of the response of viridans streptococci to penicillin in vivo.

Animals↗
PubMed1983

Importance of minimizing carry-over effect at subculture in the detection of penicillin-tolerant viridans group streptococci.

Penicillin susceptibility determinations made for 14 strains of Streptococcus mitior by two different broth dilution tests revealed small numbers of tolerant strains regardless of the volumes (0.01 and 0.1 ml) of subcultured broth. The addition of penicillinase to the subculture medium increased the number of tolerant strains significantly in 0.1 ml of subcultured broth, demonstrating that the detection of penicillin-tolerant viridans group streptococci might be hampered by the carry-over of penicillin.

Microbial Sensitivity Tests↗
PubMed1983

Occipitofrontal circumference in newborns of betamethasone treated mothers.

Celestona (betamethasone-disodiumphosphate) and Celeston (betamethasone-acetat + betamethasone-disodiumphosphate) given intramuscularly to pregnant women in order to reduce the frequency of respiratory distress syndrome does not reduce the occipitofrontal circumference of the newborn infants. Before the results from the actual work were available an impeding effect of the evolution of the brain was found in the light of animal experiments. The material is comprised of 52 newborn infants whose mothers were treated with Celestona 8 mg daily for 3 days and 46 infants treated with Celeston 12 mg daily for 3 days. The untreated population comprises 1012 newborn infants. Excluded were non-caucasian infants, twins, stillborns and cases of uncertain gestational age. The occipitofrontal circumference in normal infants and those infants treated with betamethasone were compared in Figs. 2 and 3. Focusing only upon cases in which corticoids were given more than 7 days before delivery and in which no placental dysfunction was diagnosed, no differences from the normal were found (Tabs. II and III, and Figs. 3 A and B).

Animals↗
PubMed1983

Serum estriol level during treatment with betamethasone in the last trimester of human pregnancy.

A comparison was made between betamethasone disodiumphosphate/betamethasone acetate (Celeston) and betamethasone disodiumphosphate (Celestona) in antenatally prophylactic treatment of respiratory distress syndrome syndrome (RDS). Altogether 65 pregnant women in the last trimester of pregnancy were treated with the first-mentioned drug and 62 with the second. The RDS-preventive effect was the same in the two groups. Celeston has a much longer depressive effect on the level of plasma estriol than has Celestona. Use of this drug, betamethasone disodiumphosphate, is therefore recommended in the prophylaxis against RDS.

Betamethasone↗
PubMed1983

Incidence of postextraction bacteremia under penicillin cover in children with cardiac disease.

To assess the efficacy of penicillin prophylaxis as recommended by the American Heart Association to prevent the onset of bacterial endocarditis, the incidence of postextraction bacteremia was determined in 82 children with cardiac disease who were receiving prophylactic penicillin. Aerobic and anaerobic blood cultures were taken five minutes after dental extraction, as was a blood sample to assay the serum penicillin concentration. The incidence of postextraction bacteremia was 21%. Streptococcal species accounted for half of the number of aerobes isolated. Of the isolated microorganisms, 16% were strict anaerobes. Susceptibility testing of the isolates showed that 24 penicillin-sensitive and eight penicillin-resistant microorganisms caused the bacteremia. There was neither a significant difference between the serum penicillin concentrations of children with and without bacteremia, nor between the serum penicillin concentrations of children with bacteremia due to penicillin-sensitive microorganisms and children with bacteremia due to penicillin-resistant microorganisms. It is concluded that the occurrence of postextraction bacteremia is not prevented by penicillin prophylaxis and that the serum penicillin concentration at extraction is not the discriminating factor in preventing this bacteremia. None of the children developed bacterial endocarditis. It is speculated that mechanisms not thoroughly studied are involved in the prevention of bacterial endocarditis after dental extraction.

Adolescent↗