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Biomedical subjects

J Gross

Publications and source records attributed to J Gross.

At least 271 records · Page 15Linked to original sources
PubMed1986

Effect of early and late postnatal hypoxia on subcellular synaptosomal fractions from cerebral cortex of rats. II. A quantitative ultrastructural study.

Synaptosomal subfractions were isolated by discontinuous sucrose gradient centrifugation from the P2-fraction of cerebral cortices of juvenile rats exposed to moderate intermittent hypobaric hypoxia from day 2-11 (early postnatal period) or from day 12-21 (late postnatal period) after birth. Ultrastructural investigations were carried out on fractions A and E of the preparation. Quantitative parameters of synaptosomes and mitochondria (volume density, numerical density, profile size frequency distribution) were estimated in a stereological analysis. Early postnatal hypoxia exposition strengthened the irreversible swelling of mitochondria. The effect on synaptosomes was less pronounced, very large synaptosomes showed significant condensation. Late postnatal hypoxia exposition resulted in strong condensation of synaptosomes in all size classes and similar reaction in mitochondria. Both hypoxia experiments produced an enhanced vulnerability of the synaptosomal membranes against the fractionation procedure and the appearance of monstrous large condensed synaptosomes. The results are discussed in view of hypothetical biochemical mechanisms underlying these changes.

Age Factors↗
PubMed1986

Sperm maturation associated with subfertility following hyperbaric exposure of mice.

Mice exposed to 50 ATA heliox pressure during one spermatogenic cycle subsequently exhibit subfertility which can recover over an 8-wk period. This study was designed to investigate the changes in spermatid and testicular histology associated with these phenomena. Electron microscopy of testicular tissue from hyperbaric-exposed animals revealed a significant effect on spermatogenesis including disorganization and patchy necrosis of the epithelium. Two weeks after exposure to pressure, abnormalities were more difficult to find and tissues taken from animals 8 wk after exposure were indistinguishable from normal. These data directly confirm our earlier hypothesis that chronic hyperbaric exposure has a deleterious effect on sperm maturation, which is subsequently manifest as a failure in fertilizing capacity.

Animals↗
PubMed1985

Intrarenal hemangiomas in the Klippel-Trenaunay syndrome.

The Klippel-Trenaunay syndrome is composed of the triad of unilateral limb hypertrophy, abnormalities of the deep venous system, and port-wine hemangiomas. An interesting case is presented in which there were multiple abnormalities of the renal veins and intrarenal hemangiomas resulting in renal failure in addition to the usual peripheral abnormalities.

Angiomatosis↗
PubMed1985

An unusual bovine pancreatic protein exhibiting pH-dependent globule-fibril transformation and unique amino acid sequence.

An unusual hitherto unreported protein, extracted in acid from fresh bovine pancreas, has been purified and characterized biochemically. It precipitates in the neutral pH range in the form of uniform double-helical threads, each strand of which is smooth and of uniform diameter, about 7-8 nm. The threads dissolve to a nonviscous solution below pH 3.6 and above pH 9.4, and they reconstitute reversibly in the pH range in between. The monomer in acid has an apparent molecular weight of 17,800 and consists of two disulfide-linked nonidentical polypeptide chains of different lengths. It is rich in aromatic amino acids, particularly tryptophan. There is no significant content of carbohydrate, fatty acid, or bound phosphate. The amino acid sequences of the first NH2-terminal 48 residues of the A chain and 35 residues of the B chain appear to be unique, differing from all other reported animal proteins, including those of the pancreas. Thus far, a function has not been found.

Amino Acid Sequence↗
PubMed1985

Mood and appetite during minimal-carbohydrate and carbohydrate-supplemented hypocaloric diets.

After a baseline period of free-feeding, 20 obese outpatients alternated between four 2-wk periods of minimal-carbohydrate diet (800 kcal; 58% protein and 42% fat by weight) and of a carbohydrate-supplemented diet (1,000 kcal; 42% protein, 30% fat, and 28% carbohydrate). In a comparison of psychological adjustment during the baseline and low-calorie diets, the initial 2 wk of dieting was associated with a decrease in appetite and elevation of psychological well-being, regardless of the composition of the diet. Thereafter, appetite and mood approached basal levels. Further changes in these psychological reactions to dieting did not vary with the type of diet. There was no support for the idea that a minimal-carbohydrate, protein-supplemented fast decreases appetite and elevates mood more in comparison with a similar diet containing enough carbohydrate to minimize ketosis.

3-Hydroxybutyric Acid↗
PubMed1985

Serum factors for opsonisation of non-typable Haemophilus influenzae.

Neutrophil chemiluminescence was used to assess the opsonins required for phagocytosis of non-typable Haemophilus influenzae isolated from sputum samples of patients with hypogammaglobulinaemia. Immunoglobulin was the major opsonin, whereas complement was relatively unimportant. Evidence was found for a heat-labile opsonin other than complement that enhanced phagocytosis of these organisms. Tuftsin was shown to aid phagocytosis of H. influenzae without triggering chemiluminesence.

Agammaglobulinemia↗
PubMed1985

An ex vivo method for evaluating prostaglandin synthetase activity in cortical slices of mouse brain.

The release of prostaglandin E2 (PGE2) from cortical slices of mice into incubation medium is followed for 3 h and compared to PGE2 levels in the corresponding slice. Immediately after decapitation, the rate of PGE2 released into the incubation medium is elevated and a steady low rate of spontaneous release is gained within 1-2 h of incubation. PGE2 synthesis and release is blocked in a dose-dependent manner by either indomethacin (3 X 10(-6) -3 X 10(-4) M) or flufenamic acid (2.6 X 10(-6) M) either when added in vitro or administered in vivo. Full recovery of PGE2 synthesis is reached after 3 h incubation of slices following in vivo administration of indomethacin. In vivo administration of flufenamic acid results in prolonged inhibition of PGE2 released in vitro. The inhibition of PGE2 released by indomethacin is also correlated with the slice PGE2 content. Administration of lipopolysaccharide (LPS), a known activator of phospholipase A2, results in a fivefold increase in PGE2 and a twofold increase in 6-keto-PGF1 alpha released into the medium. The release of thromboxane B2 is not affected by LPS.

6-Ketoprostaglandin F1 alpha↗
PubMed1985

Isolation, characterization, and distribution of an unusual pancreatic human secretory protein.

An unusual protein was isolated from acid extracts of normal human pancreas and pancreatic secretion in the form of uniform 7-10-nm long single threads without visible axial periodicity or other structure, as seen in the electron microscope. It accounts for as much as 300 micrograms/ml in some pancreatic secretions as measured by specific radioimmunoassay. The protein undergoes a freely reversible, pH dependent, globule-fibril transformation, being stable in the fibril form between pH 5.4 and 9.2. The monomer at acid pH has an apparent molecular weight of approximately 14,000 and consists of a single polypeptide chain, the amino acid composition of which is rich in aromatic amino acids and lacks carbohydrate, fatty acid, and phosphate. The amino acid sequence of 45 residues from the amino terminus shows no homology with any other reported protein sequences other than that of the A chain of the bovine pancreas thread protein (reported elsewhere). A sensitive radioimmunoassay employing monoclonal antibodies against human pancreatic thread protein failed to detect the antigen in a wide range of human tissues other than pancreas, nor was the antigen measurable in normal human sera. Immunohistochemistry utilizing these antibodies revealed the antigen as a component of the cytoplasm of some but not all the pancreatic acinar cells. A physiologic function has not yet been determined for this protein.

Amino Acid Sequence↗
PubMed1985

Relief of morning stiffness: a comparative study of naproxen and ibuprofen.

Morning stiffness in 75 patients with mild to moderate rheumatoid arthritis was treated with 1600 mg ibuprofen 4-times daily or 750 mg naproxen twice daily after a placebo-induced flare of this symptom. With the final daily dose of each drug administered at bedtime, both drugs significantly reduced the duration and severity of morning stiffness compared to baseline values but, on average, duration of morning stiffness tended to be shorter for naproxen patients than for ibuprofen patients. No corresponding between-drug difference was found for severity of morning stiffness.

Adolescent↗
PubMed1985

The concentration of hypoxanthine and lactate in the blood of healthy and hypoxic newborns.

This work examines the correlation between the concentration of hypoxanthine and lactate, the clinical course, and the parameters of the acid-base metabolism in newborns. In order to obtain normal values in mature, healthy newborns (Group A) 136 determinations of hypoxanthine and 126 determinations of lactate in blood were performed in the first five postnatal days. In well prematures (Group B) hypoxanthine was determined 18 times and lactate 16 times. In newborns requiring oxygen therapy including ventilator support (Group C) hypoxanthine and lactate were determined 36 and 31 times respectively. Hypoxanthine levels in the blood of mature healthy newborns decreased with increasing age. A similar course is known for lactate levels. In the group of well prematures (Group B), hypoxanthine and lactate levels have an age dependent course similar to that in group A. Correlations between hypoxanthine and lactate concentrations were observed in all three groups but were not noted to be as well defined as has been seen experimentally (e.g., by SAUGSTAD) and thus confirm the clinical results of other authors. Among the newborns requiring oxygen therapy (Group C) 7 of 36 hypoxanthine values were more than two standard deviations above those in the normal group. For lactate group C infants were in 12 of 31 cases above the two standard deviation range. The hypoxanthine and lactate concentrations of group C newborns were correlated with clinical and biochemical indicators of hypoxia. Infants with unequivocal signs of hypoxia showed elevated as well as normal hypoxanthine and lactate levels. Conversely, infants without clinical, pathological or biochemical hypoxia indicators showed in some cases elevated hypoxanthine and lactate values.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1985

Serum reduces the TSH content in rat pituitary cells in culture.

Euthyroid rat pituitary cells were plated on a natural extracellular matrix (ECM) and cultured in either a medium supplemented with hormones and growth factors (SM) or in an unsupplemented medium (USM). Hormone supplementation resulted in a marked increase in the number of cells and in a less pronounced increase in the TSH content. Addition of 10% dehormonized serum (DHS) to the medium caused a further increase in the cell number as well as a significant elevation in the GH content but, surprisingly, it caused also a dramatic decrease in the TSH content. Time course experiments revealed that the serum doubled the rate of suppression of the TSH. DHS prepared from rat serum was as effective as that prepared from foetal calf serum and heat-inactivation of the serum did not change its suppressive effect on the production of TSH. This effect was confined to the serum fraction which was precipitable with 45% ammonium sulphate but did not bind to Con-A. It is suggested that a high molecular weight protein fraction of serum reduces the number of thyrotrophs in the culture and/or decreases the rate of TSH production by these cells.

Animals↗
PubMed1985

The relations between erythrocytic and CNS parameters following postnatal hypobaric hypoxia of the rat.

In the present paper the relations between selected erythrocytic criteria and alterations of biochemical brain parameters following hypoxia were investigated in order to find out the relevance of erythrocytic criteria for the diagnosis of hypoxia-induced alterations of the CNS during development. Newborn Wistar rats (n = 80) with their mother were exposed to hypobaric hypoxia, pO2 = 11.3 kPa, from day 2-10 of life, daily for 11 h. On the 11th day of life the animals had a lower body (38%), liver (33%) and brain (17%) weight, an increased number of reticulocytes, a lower median density of peripheral red blood cells (rbc) and an increased packed cell volume (PCV) indicating stimulation of erythropoiesis. Hypoxia caused a decrease of protein concentration, of AChE activity and of the amount of DNA in the brain tissue. In addition to these parameters the cholesterol level and the protein/DNA ratio are diminished and the carboanhydrase activity is increased in the cortex. In order to quantify the changes of various brain parameters in each animal in the sense of altered development a score of these results was calculated. It can be concluded that the hypoxia-induced changes of erythrocytic parameters correlate with those of the neurochemical indices.

Animals↗
PubMed1985

Effect of chronic postnatal hypoxia on dopamine uptake by synaptosomes from striatum of adult rats.

The exposure of rats to an early postnatal hypoxia (pO2 11.3 kPa, 12 h daily, 2nd-11th day of life) causes not only long lasting changes in the dopamine (DA) release from striatum slices but also in the DA uptake by striatal synaptosomes. Adult controls have a synaptosomal DA uptake of about 5 pmoles per mg protein and per min (males 4.99, females 5.69). Rats which have been exposed to an early postnatal hypobaric hypoxia exhibit a DA uptake of 2.71 (males) and 4.53 (females) pmoles per mg protein and per min. This long-lasting effect on the dopaminergic system of the striatum must be caused by a hypoxic alteration of gene expression in a critical period of the neonatal rat brain development, with permanent effects on the DA-metabolism and/or on the function of synaptic membranes.

Animals↗