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Biomedical subjects

T Hecht

Publications and source records attributed to T Hecht.

At least 37 records · Page 2Linked to original sources
PubMed1986

Purification of a polypeptide complex (p52) belonging to the D-subspecificites of Epstein-Barr virus-induced early antigens.

A two-dimensional immunoblot analysis of chemically induced EBV DNA carrying Burkitt's lymphoma cell lines shows besides a large number of minor components at least two major groups of polypeptides: the most prominent group of polypeptides is observed in the range of 48 to 58 kDa (pI 4.5 to 8.5) and another group at 38/36 kDa (pI 4.4). A polypeptide complex (p52) belonging to the Epstein-Barr virus (EBV)-induced early antigen complex (EA) has been isolated from IdU-induced Raji and B95-8 cells as well as from n-butyrate-induced P3HR-1 cells. The p52 polypeptides have been purified by chromatography on Blue-, DEAE-, CM-, and Phenyl-Sepharose. The purification of these components of the EA complex was monitored by ELISA and by two-dimensional immunoblots using a well-characterized high anti-EBV positive human serum. The isolated polypeptides have an apparent mol wt of about 52,000 Da as determined under nondenaturing conditions by gel filtration chromatography on Sephacryl S-300. One- and two-dimensional immunoblots show a major group of polypeptides of 52 kDa (pI 8.5 to 5.5) with EA activity and some minor components with smaller size up to 40 kDa. The latter seem to be generated by limited proteolysis of p52 polypeptides. The EA activity of the isolated polypeptides could be confirmed by their reaction with IgG anti-EA positive as well as IgA anti-EA positive sera by ELISA. The purified polypeptide complex did not react with anti-EA-D negative, anti-EA-R positive sera obtained from patients with African Burkitt's lymphoma, suggesting that these polypeptides belong to the EA-D complex. The monoclonal antibody R3 reacted with the isolated 52 kDa components of EA suggesting a common epitope present on these polypeptides, the same result was obtained with three rabbit sera produced against the isolated polypeptide complex.

Antibodies, Viral↗
PubMed1984

A monoclonal antibody to hemoglobin F.

A monoclonal antibody BMU7-17 which recognizes an antigenic site unique to the cyanogen bromide fragment, CB2 (residues 56 through 133) of the gamma-chain of human hemoglobin has been produced using cell hybridization techniques. The antibody does not crossreact with hemoglobin A, the isolated alpha- or beta-chains, or with hemoglobin of various mammals. Affinity chromatography on Staphylococcal protein A-Sepharose 4B and radial immuno-diffusion revealed the antibody to be of the mouse IgG 1 class. BMU7-17 identifies F cells in adult and in cord blood specimens, as demonstrated by an indirect immunofluorescence assay. The dissociation constant of the antibody as determined using tritiated hemoglobin F with a double antibody radioimmunoassay has a Kd = 1.2 X 10(-9) moles by Scatchard plot analysis.

Animals↗
PubMed1984

Long-term effects of psychoemotional stress and tread-mill exercise on the microcirculatory system of rats.

To answer the question of whether the increased intensity of tonic or of relaxing influences acting on the microcirculatory system predominate in various chronic psychoemotional stress situations and/or after long-lasting and intense tread-mill exercise, the left-ventricular wall of the heart and the skeletal muscle or pancreas of 49 experimental and 33 control animals were investigated, using a new histomorphometric method. Chronically stressed rats showed an increase of wall thickness in microvessels documenting a long-term increase of contractile performance of wall cells for the development and maintenance of an increased contractile tone; however, there were quantitative differences depending on the manner, intensity, and duration of stress. The opposite occurred in rats exercised by a tread-mill over 6 months, 3 h per day, demonstrating the morphological correlative of metabolic long-term autoregulation. An aversion stress applied simultaneously on these animals effectively antagonized the mentioned effects of exercise.

Animals↗
PubMed1984

Visual detection of granulocyte surface antigens using the avidin-biotin complex.

A visual test for detection of granulocyte surface markers using the avidin-biotin complex (ABC) has been developed. That this assay is highly specific, reproducible, and sensitive was determined by studying the expression of HLA antigens on granulocytes with monoclonal antibodies. Further, using granulocyte specific alloantisera, the results of the ABC test compared well to data from leukoagglutination assays and indirect immunofluorescence tests. The assay is particularly advantageous in that granulocytes can be stored, only small amounts of cells and sera are needed, and heterogeneous cell populations can easily be studied.

Agglutination Tests↗
PubMed1983

Bone marrow ablation followed by allogeneic marrow grafting during first complete remission of acute nonlymphocytic leukemia.

Of 33 patients who had undergone allogeneic bone marrow transplantation during first complete remission of acute nonlymphocytic leukemia, 21 patients have now been followed in continued complete remission for 6-64 mo (median greater than 18 mo) without maintenance chemotherapy. The median age of the surviving patients is 27 yr. Transplant-related complications occurring throughout the first year after marrow grafting were fatal in 7 patients, and leukemic recurrence led to the death of 5 patients. The actuarial long-term disease-free survival is 60% and the actuarial remission rate is 79%.

Bone Marrow↗
PubMed1982

Platelet transfusion therapy in an alloimmunized patient. The value of crossmatch procedures for donor selection.

A 51-year-old patient with acute myelogenous leukemia, who was alloimmunized to platelets, failed to show adequate platelet increments after receiving transfusions of HLA grade A-identical platelets. Only platelets from an HLA grade B-matching donor gave high increments. Several crossmatching procedures were used to select platelet donors. A correlation was seen between in vitro tests and in vivo response. HLA typing has limitations in the selection of platelet-compatible donors.

Adult↗
PubMed1982

Human cyclic neutropenia transferred by allogeneic bone marrow grafting.

Human cyclic neutropenia shows many features in common with the animal model of cyclic neutropenia in grey collie dogs. Until now, however, evidence was lacking that cyclic neutropenia in man as in the dog is caused by a defect in a transplantable hematopoietic stem cell. A patient is presented who, while undergoing bone marrow transplantation as treatment for acute lymphoblastic leukemia in relapse, acquired cyclic neutropenia from her histocompatible sibling donor.

Agranulocytosis↗
PubMed1981

Histochemical demonstration of terminal deoxynucleotidyl transferase in leukemia.

White blood cells from 22 patients with leukemia and lymphoma were studied for the presence of terminal deoxynucleotidyl transferase with a peroxidase-antiperoxidase method. The enzyme was detected in leukemic cells of 5 patients with acute lymphoblastic leukemia and 1 patient with chronic myelogenous leukemia, whereas 16 patients with different forms of leukemia or lymphoma were negative for this enzyme. Comparative studies using a biochemical and an indirect immunofluorescence assay revealed complete concordance between these three methods.

Animals↗
PubMed1980

A gene controlling H-Y antigen on the X chromosome. Tentative assignment by deletion mapping to Xp223.

The existence of a strict correlation between presence of testicular tissue and presence of H-Y antigen in mammals and man leads to the conclusion that H-Y antigen is an essential differentiation factor in testicular morphogenesis. Presence of low titers of this differentiation antigen even in fertile females indicates that its morphogenetic effect depends on a threshold. Here, studies on H-Y antigen in female individuals with various deletions of the X-chromosome are reported. It turns out that deletion of Xp results in the synthesis of reduced amounts of H-Y antigen, while deletion of Xq does not. In a fertile female with only Xp223 deleted due to an X/Y translocation, including the distal Yq, presence of a reduced H-Y titer allows for the tentative assignment of a controlling gene repressing the H-Y structural gene. From the cases studied, it follows that the H-Y structural gene is autosomal and under the control of X- and Y-linked genes. The conception emerges that interaction between X- and Y-linked genes or their products results in variation of the H-Y antigen titer. The fate of the indifferent gonadal anlage to differentiate into the male or the female direction will depend on the titer of H-Y antigen reached by the action or interaction of the controlling genes involved.

Adolescent↗
PubMed1980

A new case of Y to X translocation in a female.

An unbalanced Y to X translocation due to a de novo mutation is described in a female with some clinical features of the Turner syndrome. Her karyotype is defined as 46,X,t(X;Y)(Xp11.2;Yq11). Hae III restriction analysis revealed an amount of male-specific DNA sequences in the normal male range. DNA replication analysis showed that in all cells studied the translocation X chromosome was late replicating and that the X segment of the translocation chromosome was later replicating while replication of the Y segment varied. A serologic test indicated a reduced titer of H-Y antigen, and biochemical studies for the enzyme steroid sulfatase revealed activity in the male range.

Adult↗
PubMed1980

Turner syndrome patients are H-Y positive.

H-Y antigen was examined in six patients exhibiting the characteristic features of Turner syndrome. Five of the patients were of the karyotype 45,X, and one was a mosaic 45,X/46, Xi(Xq). H-Y antigen was detected in all of them, however, compared to male controls, their antigen titer was reduced. Within the intermediate range between female and male controls, considerable interindividual variation was detected among the patients which could be due to least in part to biological variation. The findings permit the inference that the H-Y structural gene is not Y-linked, and support the assumptions of an X-linked gene escaping inactivation and of it controlling the expression of the H-Y structural gene. It is probable that the structural gene itself is autosomal. The results also suggest that male gonadal differentiation is dependent on a threshold level of H-Y antigen concentration.

Cytotoxicity Tests, Immunologic↗
PubMed1980

Effects of a substance P-analogue on blood pressure and avoidance learning of rats with spontaneous hypertension.

A shortened and modified eledoisin-hexapeptide sequence (Lys-Phe-Ile-Gly-Leu-MetNH2) was tested for their action on avoidance learning and blood pressure of rats with spontaneous hypertension (SH-rats) and intact Wistar rats. Both groups were 10, 14, and 26 weeks of age. Disorders of avoidance learning and elevation of blood pressure were likely to aggravate along with growing age of SH-rat. The used eledoisin-hexapeptide sequence is related to the essential C-terminal pentapeptide sequence of Substance P (SP). After injection of the used hexapeptide at doses of 250 microgram/kg intraperitoneally disorders in avoidance learning were completely eliminated from ten-week SH-rats or conditionally for SH-rats aged 14 and 26 weeks. Elevated blood pressure in SH-rats aged 26 weeks was reduced by the hexapeptide from 220 Torr to approximately 190 Torr. Blood pressure in SH-rats aged 14 weeks, originally about 180 Torr, was almost unaffected by the hexapeptide. Blood pressure went up from about 150 Torr to 190 in ten-week-old Sh-rats. A hypothesis was made about the mode of action of Substance P and related peptides.

Animals↗
PubMed1979

Conditioned-reflex learning of normal juvenile and adult rats exposed to action of substance P and of an SP analogue.

The actions of both Substance P, a potential neurotransmitter or modulator and of a shortened analogue on learning and memorizing processes are reported in this paper. Sixty male rats, aged 22, 14, and 10 weeks, were exposed to Substance P (Arg-Pro-Gln-Gln-Phe-Gly-Leu-MetNH2) and to a shortened hexapeptide analogue (Lys-Phe-Ile-Gly-Leu-MetNH2), doses being 250 microgram/kg and 500 microgram/kg, to test their action upon learning and memorizing processes, such as acquisition, retention, and ecphoration, by means of a conditioned-reflex locomotor defense method. Response time of all three age groups as well their retention and ecphoration were normal under the impact of hexapeptide. The effects of Substance P were decline of retention in juvenile animals (10 weeks of age) and coupling between the processes of central-nervous afference synthesis, on the one hand, and the efference integral related to motoricity, on the other, in both juvenile and adult animals. A retention test was conducted and showed that discontinuation of application of either peptide over 4 d was followed by complete inhibition of ecphoration. Learning and memorising processes were restorable by reapplication of the peptides. These findings were defined as "state-dependent learning". Only slight variation under the impact of both Substance P and the analogue was recordable by non-invasive measurement of systolic blood pressure.

Aging↗
PubMed1978

[Learning and memory processes during postnatal ontogenesis in rats with spontaneous hypertension].

The examination of learning and memory processes by a conditional reflectory locomotor avoidance reaction on 8-, 10-, 12-, 14-, 16-, 20-, 26-, and 50-week-old rats with spontaneous hypertension (SHR Okamoto/Aoki) revealed, up to an age of 20 weeks, correlations between the height of blood pressure and learning and memory performance by analogy with parameters of the hydrocarbon metabolism [1,2]. Three stages were observed: Stage I: Juvenile animals (8--10 weeks) with mean systolic blood pressure values of 150 to 170 torr showed a comparatively low restriction of learning and memory processes. Stage II: In adult animals (12--20 weeks) with mean systolic blood pressure values of 180 to 210 torr learning was inhibited by about 50%, while retention of memory was completely disturbed. Stage III: In old animals (26--50 weeks) with mean systolic blood pressure values above 200 torr the faculty to learn a conditional avoidance reflex was virtually lost. Destruction or blockage of hypothalamic behavioral substances are assumed to cause the derangement of learning and memory processes in spontaneously hypertensive rats.

Aging↗