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Biomedical subjects

D Hamann

Publications and source records attributed to D Hamann.

At least 55 records · Page 3Linked to original sources
PubMed1993

Arginine vasotocin gene expression and hormone synthesis during ontogeny of the chicken embryo and the newborn chick.

Chicken embryos at different developmental stages (embryonal day (E) 6 to 21) and chicks at posthatch day 1 (D1) were monitored for the development of their hypothalamo-neurohypophysial system as indicated by the kinetics of arginine vasotocin (AVT) gene expression via mRNA concentration and brain AVT content. Our data concerning the onset of gene expression support previous results from our laboratory and others about an early activation of the AVT gene transcriptional and translational activity around E6. We could detect measurable amounts of AVT in chicken embryo brains at E6 and an exponential increase during further development until D1. Dot blots of hypothalamic RNA extracts indicated that AVT gene transcript concentrations rose between E12 and E17 and slightly dropped thereafter. Northern hybridization showed that this drop was caused by a decrease of full length message and an increase of smaller transcripts during late embryonal and D1 stages, probably an AVT mRNA specific degradation phenomenon. The dissociation between the increase of AVT concentration and AVT mRNA concentration visible at the D1 stage might be due to accumulation and storage of AVT in the magnocellular neurons, preferentially in their axon terminals in the neurohypophysis. Blood samples taken from E14 onwards revealed a constant increase in plasma osmolality and plasma AVT concentration. Our data suggest that, in the chicken, AVT seems to be required early during embryonal development, either for osmoregulatory or further unknown functions.

Animals↗
PubMed1991

[Familial panhypopituitarism].

Two Italian brothers showed identical subsequent loss of anterior pituitary function during the first decades of their life, developing panhypopituitarism. The investigations carried out indicate that in this family the etiology is hereditary in nature, being X-chromosomal recessive or autosomal recessive, with the defect located at the level of either the hypothalamus or the pituitary gland.

Adult↗
PubMed1991

[Characterization of a T-cell subpopulation with a new monoclonal antibody BL-TSub/2].

The mab BL-TSub/2 binds to a majority (80%) of thymocytes. The antigen isolated from these cells has an apparent molecular weight of about 170 kDa. The mab BL-TSub/2 recognized antigen is expressed on approximately 50% of mature T cells in peripheral blood. The mab BL-TSub/2 does not bind to monocytes, granulocytes, platelets and CD16+NK cells. The antigen is possibly present on a part of peripheral B cells in very low density. Double labelling experiments showed that about 30% of CD4+ and 60% of CD8+ cells react with the mab BL-TSub/2. This BL-TSub/2+ subset is not identical with T-cell subpopulations till now defined. Within the CD4+ subset the majority of BL-TSub/2+ cells is included in the CD45RO+ subset while only a small proportion is CD45RA+. However, the CD8+ BL-TSub/2+ cells are mostly CD45RA+ with only few cells belonging to the CD45RO+ subset.

Antibodies, Monoclonal↗
PubMed1990

[Changes in redox potentials in serum samples as affected by adenosine triphosphate].

Irradiated serum samples show characteristic alterations of their redoxpotential. This reaction is in close correlation to metabolic alterations, that for instance occur with tumor growth or severe inflammatory diseases. The role of ATP as universal biochemical energy transmitter led us to study the influence of ATP on redoxpotential in serum. In result the sole addition of ATP to serum in vitro gave a clear alteration of the redoxpotentials. In healthy persons a shifting of redoxpotentials was seen to high positive values. On the other hand ATP has slight influence on sera of tumor patients.

Adenosine Triphosphate↗
PubMed1989

[Changes in the redox potential of serum samples following in vitro irradiation--an indicator of malignant tumor growth].

In serum samples of healthy persons and patients with malignant neoplasia the reduction-oxidation-potentials were determined. Measurements were made in untreated sera and after irradiation with different doses. Sera of healthy persons showed a decrease that of tumor patients an increase of redox-potential values. With this method malignant tumor growth can be demonstrated. It does not yet permit any statements on tumor localisation. On the other hand conclusions seem to be possible on growth speed of neoplasia. To our hitherto existing experiences estimations of redox-potential are applicable to the diagnosis of fast growing recurrences and metastases in tumor after-care, but can also support the therapeutic procedure decisively in defined differential diagnostic problems and in tumors of dignity in question.

Blood↗
PubMed1989

[Therapy of carcinoma of the oral cavity and the mesopharynx].

From the period 1969-1984 the progresses of 93 patients could be analysed, which were treated because of a squamous cell carcinoma of the mouth-cavity and the mesopharynx. Different therapeutic modalities and the prognostic relevance of locoregional tumor starting situation were analysed at criterion of survival. 44.8% of tumors of category T1, 23.3% of T2, 22.2% of T3 and 0% of T4 lived 5 years later. Only 18 months later T4-tumors turned prognostically worse. Only in fixed lymph-node of the neck (N3-category) the prognosis grew worse in our patients. The global 5-years-survival was 25.8% only. Sole operation and combination of short-time preirradiation, operation and postoperative dose-saturation gave the same 5-years-survivals (40% or 43%), in prognostically more auspicious patients in starting situation for the sole operation. From the groups of combined radiologically-surgically treated patients these ones were observed separately, whose tumors could not be removed within the healthy tissue. In these patients a pre- and postoperatively irradiation shows a little better results than postoperative radiotherapy alone, both concerning the mean survival and the 5-years-survival too. For carcinomas of the mouth-cavity (T1N0) the sole operation is the adequate treatment. For all the other cases the medium-high short-time preirradiation with operation and, depending on findings, postoperative dose-saturation should be considered. Plastic reconstructive measures can be planned 24 months later, because after this period the survival rates stay constant.

Adult↗
PubMed1984

[Finger varicose veins of the aged].

Palmar and finger varicosis is a common abnormality of the veins in the elderly. This often overlooked age-related condition is illustrated by three observations.

Aged↗
PubMed1982

Measurement of Tennessee antigen, carcinoembryonic antigen, tissue polypeptide antigen and alpha-feto-protein in body fluids associated with pregnancy.

The aim of this study was to establish if the oncofetal antigens alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), tissue-polypeptide antigen (TPA), and Tennessee antigen (TAG) were present in body fluids associated with pregnancy. There antigens were measured in amniotic fluid, cord blood, and semen. In contrast to AFP, CEA, and TPA, which were found in high concentration in amniotic fluid, the TAG concentration was lower than observed in serum. In cord blood, AFP was elevated in all samples examined. CEA was elevated in 35% of the samples. TAG was normal in all 20 samples studied. Examination of semen demonstrated that TPA, CEA, and TAG were increased over normal serum values; AFP was not increased over normal serum values in the 103 samples of semen studied. The lack of increased concentrations of TAG in amniotic fluid, cord blood and serum of pregnant women provides further evidence that this antigen is distinct from CEA, AFP or TPA. The lack of AFP in semen is interesting, and requires further investigation.

Amniotic Fluid↗