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Biomedical subjects

T Gross

Publications and source records attributed to T Gross.

At least 73 records · Page 4Linked to original sources
PubMed1992

Ability of thawed tiger (Panthera tigris) spermatozoa to fertilize conspecific eggs and bind and penetrate domestic cat eggs in vitro.

Electroejaculates from tigers were collected and half was used fresh to inseminate tiger eggs in vitro and domestic cat eggs stored in a hypertonic salt solution. The remainder was pelleted, frozen in a solution of 20% egg yolk, 11% lactose and 4% glycerol, thawed and cultured with tiger and domestic cat eggs. The motility index ((sperm % motility)+(status rating x 20))/2 for thawed spermatozoa was about 86% of that in fresh aliquots. Of the 49 tiger oocytes inseminated in vitro with fresh spermatozoa, 34 (69.4%) cleaved, compared with 33 of 47 oocytes (70.2%) cultured with thawed spermatozoa (P > 0.05). Embryos generated by either sperm treatment could develop in vitro to the 16-cell or morula stage. Fresh and thawed tiger spermatozoa were equally capable (P > 0.05) of binding and penetrating the outer and inner zona pellucida of domestic cat eggs. These results demonstrate the ability of frozen-thawed tiger spermatozoa to (i) penetrate homologous and heterologous eggs and (ii) result in conspecific, advanced development of preimplantation embryos in vitro.

Animals↗
PubMed1990

In vitro fertilization and embryo development in vitro and in vivo in the tiger (Panthera tigris).

A study was conducted to evaluate the adaptability to the tiger of an in vitro fertilization/embryo culture system previously developed in the domestic cat. In Trial I (July 1989), 10 female tigers were treated with either 2,500 (n = 5) or 5,000 (n = 5) IU eCG i.m. and with 2,000 IU hCG i.m. 84 h later. In Trial II (January 1990), 6 females (5 of which were treated in Trial I) were given 2,500 IU eCG i.m. and 2,000 IU hCG i.m. 84 h later. Twenty-four to twenty-six hours after hCG treatment, all tigers were subjected to laparoscopy, and oocytes were aspirated transabdominally. On the basis of follicular development (follicles greater than or equal to 2 mm in diameter), all females responded to exogenous gonadotropins (range, 6-52 follicles/female). Follicle number and oocyte recovery rate were unaffected (p greater than 0.05) by eCG dose or time of year. A total of 456 oocytes were collected from 468 follicles (97.4% recovery; mean, 28.5 +/- 3.4 oocytes/female). Of these, 378 (82.9%) qualified as mature, 48 (10.5%) as immature, and 30 (6.6%) as degenerate. During Trial I, 8 electroejaculates were collected from 7 male tigers, and in Trial II, 3 semen samples were collected from 3 males. Motile sperm were recovered on each occasion; the overall mean (+/- SEM) ejaculate volume was 7.5 +/- 0.7 ml, the number of motile sperm/ejaculate was 105.9 +/- 20.6 x 10(6), and the percentage of structurally normal sperm/ejaculate was 81.4 +/- 2.0%. After swim-up processing, 0.05 x 10(6) motile sperm were co-cultured with 10 or fewer tiger oocytes in a humidified atmosphere (38 degrees C) of 5% CO2 in air. Of the 358 mature oocytes inseminated, 227 (63.4%) were fertilized. Oocytes from 2 females became contaminated in culture and, therefore, were excluded from embryo cleavage calculations. Of the remaining 195 fertilized oocytes, 187 (95.9%) cleaved to the two-cell stage. No parthenogenetic cleavage was observed in noninseminated control oocytes (n = 20). Eighty-six good-to-excellent-quality two- to four-cell embryos were transferred surgically into the oviducts of 4 of the original oocyte donors in Trial I and 2 females in Trial II. A pregnancy occurred in 1 female in Trial II, and 3 live-born cubs were delivered by Caesarean section 107 days after embryo transfer. Of the 56 cleaved embryos cultured in vitro in Ham's F10 for 72 h, 14 (25.0%) were at the sixteen-cell stage, and 15 (26.8%) were morulae.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

A ribosomal protein gene family from Schizosaccharomyces pombe consisting of three active members.

Recently, we have reported the isolation and characterization of a ribosomal protein gene from the fission yeast Schizosaccharomyces pombe. This gene was called K37. Here we describe the isolation of two genes which are related to the K37 gene. Sequence analysis of these genes revealed open reading frames encoding proteins which are almost identical to the ribosomal protein K37. Furthermore, all three genes are functional as determined by Northern analysis using transformed and wild type cells. The results indicate that S. pombe contains a ribosomal protein gene family, designated the K-family, consisting of three active members. The promoter regions of the three members are compared and several common motifes are identified which might serve as transcriptional activators in these genes.

Amino Acid Sequence↗
PubMed1989

The isometric twitch of rabbit papillary muscle: reflection of the cellular calcium movements?

The cycling of the activator-Ca of the myocardium is mediated by the sarcolemma (SL) and the sarcoplasmic reticulum (SR). Both the extent and the time course of the release as well as of the removal of the activator-Ca by the SL differ from that by the SR. The visualization of these differences in the isometric myograms of isolated myocardium (Bogdanov et al. 1979; Günther et al. 1986; King and Bose 1983; Malecot et al. 1986) prompted the conclusion that distinct cellular Ca movements determine distinct parts of the isometric contraction-relaxation cycle. To test this hypothesis the effects of Ca, isoprenaline and ouabain on the isometric contraction-relaxation cycle of rabbit papillary muscles were re-evaluated. The similarities and differences in the effects of the interventions on the twitch measures could be explained by their effects on the cellular Ca movements.

Animals↗
PubMed1988

Primary structure of the ribosomal protein gene S6 from Schizosaccharomyces pombe.

We have determined the nucleotide sequence of a ribosomal protein gene which codes for the ribosomal protein S6 (rps6). The sequence analysis revealed that the gene comprises 239 amino acids, giving rise to a basic protein with a molecular weight of 27,502 Da. The product of this gene is the equivalent of the ribosomal protein S10 from Saccharomyces cerevisiae. Northern analyses and S1 mapping of both the 5' and the 3' end of the transcripts of this gene show that it is transcribed into three distinct transcripts with different sizes and heterogeneous termini. In the DNA region flanking the coding sequence, several conserved elements are present that may be involved in the transcription initiation and termination.

Amino Acid Sequence↗
PubMed1988

A modified photometric quantification of skin surface lipids sampled using the cigarette paper method.

In severe cases of acne conglobata the use of substances which considerably reduce the sebum excretion rate, such as 13-cis-retinoic acid, is reasonable. To monitor the effect of such preparation a noninvasive and accurate method for measuring skin surface lipids (SSLs) is required. A new modified photometric quantification of SSLs sampled using the cigarette paper method based on reaction with phosphovanilic reagent was introduced. Our overall results indicate that a 3-h SSLs assessment measured photometrically is as accurate as the gravimetric technique; it is reproducible in situations with low and high levels of SSLs.

Acne Vulgaris↗
PubMed1988

Dextromethorphan protects against cerebral injury following transient focal ischemia in rabbits.

We investigated dextromethorphan, both a dextrorotatory opioid derivative and a clinically tested N-methyl-D-aspartate (NMDA) receptor antagonist, in a rabbit model of transient focal cerebral ischemia. Fourteen rabbits were randomly assigned to treatment with a 20 mg/kg i.v. loading dose followed by a 10 mg/kg/hr infusion of 0.4% dextromethorphan in normal saline or with an equivalent volume of normal saline alone. One hour after treatment, the rabbits underwent a 1-hour occlusion of the left internal carotid and anterior cerebral arteries followed by 4 hours of reperfusion. The seven dextromethorphan-treated rabbits showed a significant decrease in the area of neocortical severe ischemic neuronal damage (10.5%) compared with the seven normal saline-treated controls (49.6%, p less than 0.001). The dextromethorphan-treated rabbits also demonstrated significantly smaller areas of cortical edema (10.2%) on magnetic resonance imaging than the controls (38.6%, p less than 0.01). Analysis of somatosensory evoked potentials revealed recovery of the ipsilateral amplitude to contralateral values within 5 minutes of reperfusion in the dextromethorphan-treated rabbits but not in the controls (p less than 0.01). In our rabbit model of transient focal cerebral ischemia, dextromethorphan appears to protect the brain against ischemic neuronal damage and edema, as well as to promote neurophysiologic recovery. This clinically available drug should be further investigated as having potential therapeutic value in the treatment of stroke.

Animals↗
PubMed1987

Sequence and regulatory responses of a ribosomal protein gene from the fission yeast Schizosaccharomyces pombe.

We have determined the nucleotide sequence and mapped the 5' and 3' termini of a ribosomal protein gene. The gene is transcribed into a RNA molecule of about 770 nt and appears to initiate at multiple sites, as judged by SI nuclease analysis. Gene dosage experiments with a plasmid born gene leads to a proportional increase of the messenger RNA, but not to an overproduction of the protein, suggesting a posttranscriptional control mechanism. However, the heat shock response of this gene indicates that there is also a potential for transcriptional control. Comparison of the 5' flanking region of this gene with the ribosomal protein gene S 6 from Schizosaccharomyces pombe and with ribosomal protein genes from Saccharomyces cerevisiae revealed homologous sequences, which may be involved in the regulation of ribosomal protein genes.

Amino Acid Sequence↗
PubMed1986

Persistence of cholera in the United States: isolation of Vibrio cholerae O1 from a patient with diarrhea in Maryland.

A case of cholera was identified in Baltimore County, Md., in October 1984. The Vibrio cholerae O1 isolate from the patient was hemolytic, biotype El Tor, serotype Inaba, and was toxigenic by the Y-1 adrenal cell assay; on Southern blot analysis, the strain had a unique HindIII restriction site in the cholera toxin gene identical to that of other U.S. V. cholerae O1 isolates. Two days before he became ill, the patient had eaten meat from crabs harvested along the Texas coast.

Aged↗
PubMed1986

Modification of relaxation of isometrically contracting rabbit papillary muscle by calcium, isoprenaline, ouabain and amiloride.

The influence of isoprenaline, ouabain, amiloride, as well as enhanced extracellular Ca on the time course of relaxation of the isometrically contracting papillary muscle was investigated. Under the experimental conditions used the relaxation rate shows different phases, which are modified characteristically. It is concluded that this reflects the different involvement of the Ca transport mechanisms for the relaxation.

Amiloride↗
PubMed1985

Perinatal problems of the obese mother and her infant.

The health consequences of obesity in adults encompass both metabolic and cardiovascular complications. Pregnancy in obese women also has a particular set of problems. For the obese pregnant woman, these include weight gain less than 5.4 kg, chronic hypertension and superimposed preeclampsia, gestational diabetes, multiple gestation, and the potential for a macrosomic child. The combination of obesity and maternal diabetes does not appear to have an additive effect on the excessive growth of infants of obese mothers. Furthermore, despite inadequate weight gain, hypertension, and multiple gestation, infants of obese mothers are usually born with a greater birth weight than those of nonobese women. In addition, the incidence of intrauterine growth retardation is lower after an obese pregnancy. Neonates born to obese mothers have increased risk for birth asphyxia and birth trauma. Recently infants born to obese women were noted to have transient neonatal fasting asymptomatic hypoglycemia. Hyperinsulinism is not present in the infants of obese mothers; thus, alternate fuel mobilization (free fatty acids, glycerol, ketones) may respond to the hypoglycemic stimulus. Suggestions and rationale for the management of the pregnant obese woman, fetus, and newly born infant are discussed in the text.

Birth Weight↗
PubMed1984

Bioassay for salmon prolactin using hypophysectomized Fundulus heteroclitus.

A bioassay for salmon prolactin (PRL) is described. This assay which is based on the sodium-retaining action of PRL in the hypophysectomized killifish, Fundulus heteroclitus, has proved to be rapid, sensitive (250 pg PRL per gram of fish), and specific. The procedure has been used to characterize the biological activity of a highly purified PRL from the pituitaries of the chinook salmon, Oncorhynchus tschawytscha, and a similar PRL isolated (by acid buffer polyacrylamide disc gel electrophoresis) from pituitaries of coho salmon (O. kisutch) (MW ca. 22,000; isoelectric point greater than 9).

Animals↗
PubMed1984

Intrauterine growth and postnatal fasting metabolism in infants of obese mothers.

We compared neonatal fasting metabolism in 12 infants of obese women and 10 control infants born to lean mothers. Weight gain during pregnancy was less among obese women (7.2 vs 13.6 kg). Term infants born to obese women were heavier (3.9 bs 3.2 kg), had greater triceps and midscapular skinfold thicknesses, and had heavier placentae (687 vs 572 gm). Length and head circumference were not affected. After birth, fasting blood glucose concentrations declined in obese infants to hypoglycemic levels at 60 minutes of the study (26.3 vs 63.1 mg/dl). Insulin levels were not statistically different between the two groups. The postnatal rise of free fatty acids and glycerol was augmented in infants of obese mothers, whereas the decline of plasma beta-hydroxybutyrate values was augmented in infants of obese mothers, whereas the decline of plasma beta-hydroxybutyrate values was attenuated. Cord vein and artery plasma triglyceride concentrations were elevated in infants of obese mothers, and the usual rise of triglycerides with fasting after birth was further augmented in these infants. These data suggest that despite less than optimal maternal weight gain, sufficient or even surplus fuels are provided to the fetus of the obese mother and results in augmented fetal growth. Furthermore, the occurrence of fasting hypoglycemia necessitates careful monitoring of postnatal blood glucose values.

3-Hydroxybutyric Acid↗
PubMed1984

Expression of Epstein-Barr virus (EBV) DNA and cloned DNA fragments in human lymphocytes following Sendai virus envelope-mediated gene transfer.

Purified EBV DNA and cloned DNA fragments were trapped in Sendai virus (SV) envelopes during envelope reconstitution. The DNA-loaded reconstituted envelopes (RSVE/DNA) served as gene-transfer vehicles using the capability of RSVE to fuse with normal and tumor cells. The efficiency of RSVE-mediated EBV DNA transfer into lymphoid tumor cells and fresh human lymphocytes was 5-10% of the enveloped 3H-labeled EcoRI fragment B of EBV DNA. Purified intracellular EBV (B95-8 strain) DNA induced EBV nuclear antigen (EBNA) in 0.2-1% of human lymphocytes, transiently stimulated cellular DNA synthesis, but did not fully transform cells. Cloned Sal I F1 fragment [approximately equal to 9 kilobase pairs (kbp)] and a smaller BamHI K (5.2 kbp) fragment from the same region of B95-8 EBV DNA induced EBNA in 2-4% of human lymphocytes but did not stimulate DNA synthesis nor transform cells. Cloned BamHI D1 fragment (approximately equal to 9 kbp) from AG-876 virus DNA, or a combination of cloned BamHI X and H fragments (approximately equal to 2 and 7 kbp, respectively) from the similar region of B95-8 virus DNA, significantly stimulated lymphocyte DNA synthesis, but EBNA could not be detected and transformation was not achieved. Early antigen and viral capsid antigen were not observed with any of the fragments tested. Our results suggest that the induction of EBNA and stimulation of lymphocyte proliferation are not controlled by the same region of EBV DNA.

Base Sequence↗
PubMed1980

Obesity in pregnancy: risks and outcome.

Obesity has been associated in the literature with other pregnancy risks such as hypertension and diabetes mellitus, but disagreement persists about the expected course and complications of labor. Also, the effects of obesity on intrauterine growth and gestational duration have not been well defined. This study of 2746 consecutive deliveries used a computer-based uniform perinatal record to compare 300 pregnancy risk and outcome factors for obese and nonobese patients. The 279 obese women (more than 90 kg at some time during the pregnancy) were found to be older and of higher parity than the 2467 who were not obese. Those in the obese group were at increased antepartum risk and had increased frequencies of chronic hypertension, inadequate pregnancy weight gain, twin gestation, and diabetes mellitus. Oxytocin induction and repeat cesarean sections were performed more frequently for the obese patients, with no increase in complications during the current labor. The frequency of labor abnormalities, oxytocin augmentation, and primary cesarean section was similar to that of the comparison group. Examination of infant outcome revealed similar Apgar scores and perinatal mortality in the 2 groups, but fewer low-birth-weight infants (under 2500 g) and more macrosomic babies (over 4000 g) occurred in the obese population. This increase in birth weight was accounted for not only by an increase in the birth weight percentile, but also by a significant lengthening of the period of gestation.

Adult↗