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Biomedical subjects

H Meyer

Publications and source records attributed to H Meyer.

At least 19 recordsLinked to original sources
PubMed1992

[Energy intake of adult Great Danes].

Energy intake and weight development were recorded in 5 adult Great Danes kept in outdoor kennels during maintenance, pregnancy and lactation. In periods with constant weights the energy requirement was 0.96 MJ DE/kg BW0.75/d with a minimum in summer (0.82) and a maximum in winter (1.1). In pregnancy (weight gain depending on litter size 7-15 kg) energy intake (ad-lib.-feeding) was similar to maintenance. During lactation energy intake reached 1.6-1.7 MJ DE/kg BW0.75/d with a dry matter intake of 83 g/kg BW0.75/d. Pups of great litters had to be fed with milk substitute for normal weight development.

Animal Feed↗
PubMed1992

Encephalitis and chorioretinitis associated with neurotropic African horsesickness virus infection in laboratory workers. Part II. Ophthalmological findings.

Four laboratory workers developed uveitis-chorioretinitis, associated with encephalitis in 3 cases. The retinitis was characterised by haemorrhages and areas of retinal oedema, most marked over the posterior polar regions, and was associated with exudative retinal detachments. The lesions progressed over weeks and showed a severe retinal arterial vasculopathy with arteriolar narrowing, ghost vessel formation and the development of optic atrophy. The picture in 2 of the patients resembled that of the acute retinal necrosis syndrome (ARN). Antibodies to African horsesickness (AHS) virus were detected. The serology for AHS virus was positive in all 4 patients as well as in 5 of 15 laboratory workers from the same facility who were clinically and ophthalmologically normal. This is to our knowledge the first description of subclinical and probable clinical neurotropic AHS virus infection in man. AHS is a hitherto-unrecognised possible cause of viral retinitis and the ARN syndrome.

Adolescent↗
PubMed1992

The switch of tau protein to an Alzheimer-like state includes the phosphorylation of two serine-proline motifs upstream of the microtubule binding region.

The paired helical filaments (PHFs) of Alzheimer's disease consist mainly of the microtubule-associated protein tau. PHF tau differs from normal human brain tau in that it has a higher Mr and a special state of phosphorylation. However, the protein kinase(s) involved, the phosphorylation sites on tau and the resulting conformational changes are only poorly understood. Here we show that a new monoclonal antibody, AT8, records the PHF-like state of tau in vitro, and we describe a kinase activity that turns normal tau into a PHF-like state. The epitope of AT8 is around residue 200, outside the region of internal repeats and requires the phosphorylation of serines 199 and/or 202. Both of these are followed by a proline, suggesting that the kinase activity belongs to the family of proline-directed kinases. The epitope of AT8 is nearly coincident with that of another phosphorylation-dependent antibody, TAU1 [Binder, L.I., Frankfurter, A. and Rebhun, L. (1985) J. Cell Biol., 101, 1371-1378], but the two are complementary since TAU1 requires a dephosphorylated epitope.

Alzheimer Disease↗
PubMed1992

Endogenous and environmental factors influence 35S promoter methylation of a maize A1 gene construct in transgenic petunia and its colour phenotype.

30,000 transgenic petunia plants carrying a single copy of the maize A1 gene, encoding a dihydroflavonol reductase, which confers a salmon red flower colour phenotype on the petunia plant, were grown in a field test. During the growing season plants with flowers deviating from this salmon red colour, such as those showing white or variegated phenotypes and plants with flowers exhibiting only weak pigmentation were observed with varying frequencies. While four white flowering plants were shown at the molecular level to be mutants in which part of the A1 gene had been deleted, other white flowering plants, as well as 13 representative plants tested out of a total of 57 variegated individuals were not mutants but rather showed hypermethylation of the 35S promoter directing A1 gene expression. This was in contrast to the homogeneous fully red flowering plants in which no methylation of the 35S promoter was observed. While blossoms on plants flowering early in the season were predominantly red, later flowers on the same plants showed weaker coloration. Once again the reduction of the A1-specific phenotype correlated with the methylation of the 35S promoter. This variation in coloration seems to be dependent not only on exogenous but also on endogenous factors such as the age of the parental plant from which the seed was derived or the time at which crosses were made.

Alcohol Oxidoreductases↗
PubMed1992

Immunohistological and immunoelectron microscopic identification of TNF alpha in normal human and murine epidermis.

The presence, distribution and cellular localization of tumour necrosis factor-alpha (TNF alpha) were investigated in normal human and murine epidermis using immunohistological and immunoelectron microscopic methods with monoclonal and polyclonal antibodies. The immunostaining revealed an intercellular plasma membrane and cytoplasmic labelling of the epidermal keratinocytes, but no labelling of Langerhans cells, melanocytes and Merkel cells. Large amounts of TNF alpha were regularly found in the sebaceous glands. These findings demonstrate that epidermal keratinocytes and especially sebocytes produce and release TNF alpha and that this keratinocyte-derived cytokine may be important for the structural and functional homeostasis of normal epidermis.

Adult↗
PubMed1992

Rapid identification and differentiation of the vaccine strain Rac H from EHV 1 field isolates using a non-radioactive DNA probe.

A method for rapid differentiation between the EHV 1 live vaccine strain Rac H and field isolates is described. Total DNA was isolated from virus-infected small scale cell cultures. DNA fragments digested with restriction endonuclease BamHI were separated, transferred and immobilized on filter membranes. A Digoxigenin-labeled probe derived from EHV 1 was used for hybridization. This probe hybridized specifically to sequences of the inverted terminal repeat region which in case of Rac H include a deletion of 0.8 kb. By comparing the different migration patterns after blot hybridization it could be shown that in 65 isolates from cases of abortion the live vaccine strain Rac H was not involved.

Abortion, Veterinary↗
PubMed1992

Glycoprotein gp116 of human cytomegalovirus contains epitopes for strain-common and strain-specific antibodies.

Glycoprotein gp116 of human cytomegalovirus (HCMV) is a target for neutralizing antibodies. Gp116 is a component of the gCI complex which consists of gp58 and gp116. Like its homologue, glycoprotein B of herpes simplex virus type 1, gp116 contains a highly antigenic region in the N-terminal part of the molecule, between amino acids 28 and 84. Prokaryotic expression plasmids and synthetic peptides were used to define binding sites for mouse and human monoclonal antibodies (MAbs) as well as HCMV convalescent sera. Site I, located between amino acids 68 and 77, contains an epitope recognized by the human MAb C23, which is capable of neutralizing HCMV independently of complement and the site is conserved between HCMV strains. Of HCMV-positive human sera, 53% recognized site I. Site II was mapped using mouse MAbs as well as human sera. It is located between residues 50 and 54, an area which is not conserved between strains AD169 and Towne, the two laboratory strains of known sequence. Strain-specific antibodies were detected in 25% of human sera. Site II-specific antibodies, purified from human sera by affinity chromatography, were found to be incapable of neutralizing HCMV in tissue culture.

Amino Acid Sequence↗
PubMed1992

Cytotoxicity of cyanobacterium Microcystis aeruginosa.

Cytotoxic effects of crude extracts and fractions of the purification steps towards Microcystin-LR (MCYST-LR) were investigated in vitro. Cytotoxicity was evaluated by measure of lactate dehydrogenase liberation of Chang liver cells and by hemolysis. Crude extracts of strain PCC 7806 damaged the cells within a few minutes. In contrast, MCYST-LR did not show any detectable cytotoxic effects. The cytotoxic activity could be related to a heat-labile substance with a molecular weight of about 30,000 Da.

Animals↗
PubMed1992

Heart transplantation at the Heart Center North Rhine-Westphalia.

Since 1989, 427 heart transplants were performed at our center, limited only by donor availability, not by moderating donor criteria. Therefore, an increasing number of possible recipients was bridged with mechanical circulatory support systems. Immunosuppression was based on double-drug therapy (CsA, Aza) without steroid maintenance if possible and without mono- or polyclonal antibody prophylaxis. Monitoring adult transplant patients was based on endomyocardial biopsies only during the first 12 months posttransplant. In the pediatric group, only noninvasive diagnostic procedures were performed. Our present 1- and 3-year survival rates for heart transplant patients are 85% and 78%, respectively. We believe that only centers performing approximately 1,000 routine open-heart surgery procedures per year should be allowed to perform heart transplantation, with a minimum of 25 procedures per year (5). Our goal is to start our heart-lung and lung transplant programs in the near future. Our research interests are mainly in the field of postoperative monitoring, induction of immune tolerance, and in establishing a method to determine an individual immunosuppression protocol for each patient (6).

Academic Medical Centers↗
PubMed1992

[The effect of a different energy supply on the growth intensity and skeletal development of growing Great Danes. 2. Effect on insulin-like growth factor I and on thyroid hormones].

In an experiment with 13 growing Great Danes (littermates) fed ad libitum (4 dogs) or restrictively (70% of ad libitum energy intake; 9 dogs), concentrations of insulin-like growth factor I (IGF-I), 3,5,3'-triiodothyronine (T3) and thyroxine (T4) were measured in blood samples until the age of 6 months. In the ad libitum fed group, levels of T3 and T4 were partially and of IGF-I were significantly (p < 0.01) elevated as compared with the control dogs. Postprandial changes of IGF-I were absent in growing Great Danes as well as in a reference group of 3 adult beagles. Increased concentrations of IGF-I, T3 and T4 could be causally related to osteochondrosis, which frequently occurs in intensively fed dogs.

Animal Feed↗
PubMed1992

[The effect of a different energy supply of growing Great Danes on body weight and skeletal development. 1. Body weight development and energy requirement].

27 Great Danes (from 3 litters) were fed ad lib. (n = 9) or with an energy intake (n = 18) restricted to 80 and 70% of the paired ad lib. group, respectively, and a nearly equalized protein and nutrient supply meeting the current recommendations (8 dogs of the restricted groups were bearing weight loaded [15% of own BW] belts in the scapular region). Dogs were weighed weekly, shoulder height, approximate length of the forearm and foot were recorded in certain intervals. In plasma protein, urea, Ca, P, Cu, Zn, and alkaline phosphatase were determined. Intake of digestible energy (according to the results of digestive trials) was recorded daily.

Animal Feed↗
PubMed1991

Heart catheterization in a neonate by interacting magnetic fields: a new and simple method of catheter guidance.

Catheter guidance in a critically ill neonate can be difficult and hazardous. A new technique of directing a catheter based on the interaction of magnetic fields is described. A strong external permanent magnet is moved across the body surface to control the magnetic tip of a catheter in the body. We report on the first clinical case of such a heart catheterization in a neonate with complex congenital heart disease. This method can also be used for other invasive investigations in the neonatal period.

Angiography, Digital Subtraction↗
PubMed1991

Nonisotopic in situ hybridization as a method for nondisjunction studies in human spermatozoa.

Human spermatozoa were studied with a nonradioactive in situ hybridization method. Using a chemically modified DNA probe and immunocytochemical reactions for visualization, it was possible to obtain hybridization signals in 31 of 32 semen samples. Positive hybridization reactions, depending on cell accessibility, varied from 40% to over 90% for the different samples. Using a chromosome 1-specific DNA probe, disomy for this chromosome was found in 0.67% of all accessible sperm cells.

Adult↗
PubMed1991

Primary repair of complete atrioventricular septal defect in infancy.

Forty infants with complete atrioventricular septal defect have undergone primary repair within their 1st year of life. The mean age at time of surgery was 4 months (range 1-12 months) and the mean weight 4.2 kg (range 2.9-7.0 kg). Either the one- or the two-patch method was used. Four patients died (10%). There were no late deaths. Three patients needed reoperation due to mitral valve insufficiency. Postoperative complications were: 1 total atrioventricular block in an infant with an absent ventricular septum 3 weeks after surgery, 9 complete right bundle branch blocks, 3 small residual ventricular septal defects. Mean follow-up of the 36 survivors is 22 months (3-46 months). Thirty (83%) are in NYHA functional class I, 4 (11%) in NYHA class II and 2 (6%) in NYHA class III. No atrioventricular valve regurgitation is detectable by the color Doppler technique in 19 (53%) patients. Mitral incompetence is mild in 13 cases (36%) and moderate in 4 (11%). In ten recatheterized patients the average systolic pulmonary to systemic artery pressure ratio dropped from 1.0 to 0.42 and the average pulmonary arteriolar resistance was reduced from 5.5 to 3.9 U/m2. All but one patient gained weight and underwent adequate statomotoric development. Primary repair should be performed at the age of 5-6 months or even earlier, if pulmonary arteriolar resistance exceeds 5 U/m2.

Cardiac Catheterization↗
PubMed1991

Early rhythm disorders after arterial switch and intraatrial repair in infants with simple transposition of the great arteries.

Between 1986 and 1990 68 infants with transposition of the great arteries (TGA) have been repaired within their first six months of life. From the 51 simple TGA, forming the study group, 20 underwent intraatrial repair according to Mustard and Brom (group I) and 31 received the arterial switch procedure (group II). We compared the observed rhythm disorders after both surgical methods. There were no deaths in group I and 3 deaths in group II. Group I: 7 cases (35%) had early postoperative arrhythmias, 6 patients received transient therapy. There were 3 cases of supraventricular tachycardia (SVT), 2 cases of frequent supraventricular premature beats (SVPB), 1 infant with temporary AV junctional rhythm and 1 with temporary total AV block. Both needed external pacemaker support for maximal two days. Group II: 14 cases (50%) presented rhythm disorders, 13 patients received transient therapy. There were 4 SVT and 3 SVPB. The time of occurrence was between the first and the sixth postoperative day. 2 cases of temporary AV junctional rhythm and 2 infants with transient total AV block needed external pacemaker support for maximal two days. 3 cases with relative sinus bradycardia (less than 130 beats/min) improved clinically with temporary external pacemaker support for several hours. Finally all patients of both groups were in sinus rhythm and after two months all antiarrhythmic drugs could be stopped. There have not been any ventricular arrhythmias in the early postoperative period. During the whole follow up (mean 28 months, range 4-60 m) no arrhythmias reappeared with two (4%) exceptions.

Arrhythmias, Cardiac↗