Search PubMed⌕ Search

Biomedical subjects

J Gross

Publications and source records attributed to J Gross.

At least 343 records · Page 19Linked to original sources
PubMed1980

Suppression of thyrotropin by 3,5-dimethyl-3'-isopropyl-L-thyronine in euthyroid and hypothyroid rats.

The effect of 3,5-dimethyl-3'-isopropyl-L-thyronine (DIMIT) a nonhalogenated thyroid hormone analog, on plasma and pituitary TSH levels was studied in euthyroid and 5-day-thyroidectomized (T-5d) rats. The minimal dose of DIMIT which suppressed basal plasma TSH for a 24-h period was 5.3 micrograms/100 g BW in the euthyroid rats and 5.2 micrograms/100 g BW in the T-5d group. The equipotent doses of T3 were 1.0 and 1.5 micrograms/100 g BW, respectively. Thus, the apparent DIMIT to T3 molar ratio ranged from 6.6 in the hypothyroid to 10 in the euthyroid group. The suppression of TRH-induced TSH release in the euthyroid rats required a high dose of DIMIT (9.2 micrograms/100 g BW), resulting in a DIMIT to T3 molar ratio of 17. Time-course studies comparing the effects of equipotent doses of DIMIT and T3 on TSH release rates in euthyroid and T-5d rats have shown a maximal suppression by 3--24 h after the administration of both T3 and DIMIT. However, the recovery from the effect was slower after T3. TSH synthesis in the T-5d group was similarly suppressed by DIMIT and T3. DIMIT has significant thyromimetic activity in euthyroid and hypothyroid rats, as evidenced by the suppresion of TSH synthesis and release.

Animals↗
PubMed1980

[Development of bilirubin-UDP-glucuronosyltransferase (EC 2.4.1.17) and the concentration of transport proteins Y and Z of rat liver under postnatal hypoxia].

The development of bilirubin-UDP-glucuronyltransferase (bili.-UDP-GT) activity and the concentration of transport proteins Y and Z from the livers of Sprague-Dawley rats were studied in the first 20 days from birth and compared to the findings obtained on postnatally hypoxic rat newborns. The activity of bili.-UDP-GT is very low immediately after birth, and rises within the first 4 days to values distinctly exceeding adult values. Onset of hypoxia within the first 3 h of life inhibits the development of bili.-UDP-GT; later onset of hypoxia is without effect. The development of Y and Z transport proteins proceeds more slowly than that of bili.-UDP-GT. The binding properties of the Y protein in regard to substrate affinity. There is evidence in newborns for interactions in terms of cooperative binding. No influence of hypoxia on the development of Y and Z transport proteins is demonstrable.

Aging↗
PubMed1980

[Behavior of creatine in red blood cells and blood plasma of adult rats following exposure to hypoxia].

Adults rats exposed to hypoxia showed a definite increase of creatine concentration in red cells and plasma. The rise in cell creatine 37 h after the beginning of hypoxia had disappeared 2 days after the end of hypoxia. It is explained by the expulsion of preformed reticulocytes from the bone marrow. The increase of plasma creatine is supposed to be due to hypoxic damage to the muscles, which release creatine into the blood stream.

Animals↗
PubMed1979

Regulation of corneal collagenase production: stimulation of serially passaged stromal cells by blood mononuclear cells.

After three or more passages, stromal cell outgrowths from explants of normal rabbit corneas and from corneas previously burned with alkali did not produce collagenase until they were stimulated by the addition of rabbit blood-derived mononuclear cells or media conditioned by them. Normal stromal cells required stimulation by lymphocytes or their products from alkali-burned animals, whereas those from alkali-burned corneas were stimulated by lymphocytes from either normal or alkali-burned rabbits.

Animals↗
PubMed1979

Procollagen segment-long-spacing crystallites: their role in collagen fibrillogenesis.

Naturally occurring segment-long-spacing crystallites of procollagen collagen have been found in the culture medium of fibroblasts from chick embryo tendon, human skin, and dermatosparaxic calf skin; in whole-mount preparations of cultured human skin fibroblasts; in homogenates of lathyritic chick embryo tendon, cartilage, and cornea; and in a partially purified preparation of procollagen. Bundles of similar aggregates occurred within secretory vacuoles of collagen-synthesizing fibroblasts and chondrocytes. These observations suggest that fibroblasts and chondrocytes secrete procollagen assemblies that are stable in the extracellular environment. We propose that subsequent enzymatic processing is accompanied by direct incorporation of such structures into the assembling fibril, which then may be considered as an n X 67 nm staggered array of segment-long-spacing crystallites.

Animals↗
PubMed1979

Hyaluronate and invasiveness of the rabbit V2 carcinoma.

We propose that hyaluronate, a major component of extracellular matrices through which cells migrate during embryonic tissue development and in regenerative processes, is also concentrated in the environment through which neoplastic cells invade local host tissues and may facilitate this process. The hyaluronate content of invasive V2 carcinoma grown in rabbit was found to be 3-4 times greater than that of the same tumor grown in the nude mouse, in which it is noninvasive. Moreover, hyaluronate concentrations were most elevated in the connective tissue interface between the tumor mass and the neighboring host tissue in the invasive rabbit tumors. The particular site of tumor implantation in the rabbit or nude mouse did not affect the concentrations of hyaluronate in either the parenchyma or the surrounding connective tissue. Similar values were obtained for neoplasms grown in muscle, which normally contains little hyaluronate, and in subcutaneous tissue, which is relatively rich in this glycosaminoglycan.

Animals↗
PubMed1979

TSH synthesis and release in the thyroidectomized rat: b) effect of T3.

The time and dose dependent effects of T3 on the anterior pituitary (AP) TSH release and synthesis were studied in rats 5 days after thyroidectomy (T-5d). T3, in various doses, was injected iv to animals which were kileed at various times later. Plasma and AP TSH were measured. T3 lowered plasma TSH to a minimum within 3 h. An inverse linear relationship was found between T3, up to 634 +/- 134 ng/100 g b.w. (mean +/- SD) and plasma TSH. Higher doses of T3 did not lower plasma TSH any further. At T3 of 634 +/- 134 ng/100 g b.w. the specific AP binder was calculated to be 68% to 90% saturated; thus suggesting a relationship between occupancy by T3 of the AP binder and the regulation of TSH release. The TSH release and synthesis rates were compared after 0.5 micrograms, 1 microgram and 25 micrograms T3. All three doses of T3 suppressed the release as well as the synthesis. The effect of T3 on the synthesis rate, however, lagged behind the effect on the release both in time and magnitude.

Animals↗
PubMed1979

[In vitro investigations of microphages function in patients with chronic mucocutaneous candidosis (author's transl)].

In five patients with either familial or non-familial type of chronic mucocutaneous candidosis some properties of phagocytic function of the polymorphonuclear leucocytes (PMNL) have been studied in vitro. In each of the patients there were found: a) a decreased chemotactic activity of PMNL, b) a weakness of intake and of intracellular destruction of Candida albicans cells by PMNL, c) an impairment of phagocytosis and intracellular killing of Candida albicans as well of Staphylococcus aureus by PMNL. The rate of phagocytosis of heat-inactivated Candida albicans cells by PMNL was normal in each case. In the serum of two patients a phagocytosis inhibiting factor is supposed to exist. In PMNL of 3 patients a defective activity of NADH-dependent oxidase was found. The occurrence of hereditary CMCC in a father and his two daughters points to an autosomal dominant trait, whereas in most cases of familiar CMCC hitherto described an autosomal recessive mode of transmission was found.

Adult↗
PubMed1979

[Erythropoietin and erythropoiesis inhibition factor in the newborn and infants with cyanotic heart abnormalities].

In the present study, hematocrit, pO2 in the capillary blood, reticulocyte count, erythropoietin activity in plasma and activity of the erythropoiesis inhibition factor in 24-h collective urine were determined in newborns and infants with cyanotic malformations of the heart (transpositions of the big arteries). The plasma of the healthy newborns shows immediately after birth an erythropoietin activity below 1%, as measured by the 59Fe incorporation. The erythropoietin activity of the plasma of infants with cyanotic malformations of the heart is enhanced up to the 14th day of life. In the period of day 14--30 it corresponds to the values of healthy newborns despite the persistence of hypoxia. After the 30th day of life there is again demonstrable an increased erythropoietin activity in the plasma of infants with cyanotic malformations of the heart. Obviously, the low values of 59Fe incorporation from day 14--30 are due to the occurrence of the erythropoiesis inhibition factor. In the urine of infants with cyanotic malformations of the heart there could be demonstrated distinct inhibitions of the stimulated erythropoiesis of the polycythemic mouse. The present studies suggest that the erythropoiesis inhibition factor occurs in postnatal development irrespectively of the degrees of O2-supply of the tissue, and is possibly dependent on the gestational age.

Aging↗
PubMed1979

[Pre- and postoperative erythrocyte volume distribution curves in children with cyanotic heart defects].

The behaviour of the volume distribution curves (VVK) of red blood cells in children with cyanosed organic heart defect is reported by taking preoperative and postoperative observations as a basis. MCV determined from the volume distribution curve amounts to 80.3 micron3. If the volume distribution curves of the preoperative patient group are compared with the postoperative patient group (4 months) by means of the criteria DSmax, DS, inclination and dispersion, no significant changes can be identified. Therefore, shifting maturity divisions cannot be assumed in children with cyanosed organic heart defects, even in those with a preoperative hypoxia of a high degree.

Adolescent↗
PubMed1978

Covalent structure of collagen: amino acid sequence of chick skin collagen alpha1(1)-CB6B.

The amino acid sequence of the peptide alpha1(I)-CB6B, the carboxyl-terminal peptide containing 91 residues of alpha1(I) chain of chick skin collagen, is described. The amino acid sequence was determined by automated Edman degradation of intact peptide plus its tryptic and thermolytic peptides. The comparison of this sequence with the corresponding segment of previously published alpha1(I)-CB6 of calf skin collagen showed a sequence identity of 90%.

Amino Acid Sequence↗