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Biomedical subjects

J Chase

Publications and source records attributed to J Chase.

At least 37 records · Page 2Linked to original sources
PubMed1992

Comparison of pregnancy rates following in vitro fertilization-embryo transfer between the donors and the recipients in a donor oocyte program.

Our in vitro fertilization (IVF) program provides a unique opportunity to evaluate influences of hormonal milieu on pregnancy outcome, by using a shared pool of oocytes obtained by donors (in exchange for financial assistance). The study presented herein evaluated 38 retrieval cycles (28 oocyte donors/22 recipients). No difference in mean number of embryos transferred was seen (2.7 in the donors vs 2.8 in the recipients). However, a statistically significant difference was seen in the pregnancy rates per retrieval (10.5% donors vs 29% recipients) and per transfer (4/35, 11.1%, vs 11/34, 32.3%). Abortion rates were similar (25% donor, 27.2% recipients). These data suggest that other reports of higher pregnancy rates from donor oocyte programs may not be due exclusively to better-quality oocytes. Possibly a negative effect of hyperstimulation or adverse endometrial environment of the donor (possible chronic endometritis) may explain these data.

Abortion, Spontaneous↗
PubMed1992

A microsomal fatty acid synthetase from the integument of Blattella germanica synthesizes methyl-branched fatty acids, precursors to hydrocarbon and contact sex pheromone.

Methyl-branched fatty acids present in the integument of the German cockroach, Blattella germanica, were identified by gas chromatography-mass spectrometry of their methyl esters and reduction products (alkanes) as n-3-, n-4-, n-5-, n-7-, n-8-, and n-9-monomethyl fatty acids and as n-5,9-, n-3,9-, and n-3,11-dimethyl fatty acids with 16 to 20 total carbons. These fatty acids have the same branching patterns as do the major hydrocarbons of this insect, including 3,11-dimethylnonacosane, the precursor to the major contact sex pheromone, and are presumed to be intermediates in hydrocarbon formation. A novel microsomal fatty acid synthetase (FAS) located in the integument of this insect incorporated [methyl-14C]methylmalonyl-CoA into methyl-branched fatty acids as demonstrated by radio-high-performance liquid chromatography. A cytosolic FAS is also present in the integument. Both the microsomal and the soluble FAS incorporated [methyl-14C]methylmalonyl-CoA into fatty acids, but only the microsomal FAS was able to efficiently use methylmalonyl-CoA as the sole elongating agent. This is the first report of the characterization of methyl-branched fatty acids from the integument of an insect and of an integumental microsomal FAS that incorporates methylmalonyl-CoA into branched fatty acids.

Acyl Coenzyme A↗
PubMed1991

Hepatic arterial infusion chemotherapy with complete hepatic venous isolation and extracorporeal chemofiltration: a feasibility study of a novel system.

When chemotherapeutic drugs with low liver extraction are used for hepatic arterial infusion (HAI), dosage limits are usually determined by systemic rather than hepatic toxicity. If such agents could be administered by HAI at dosages limited by hepatic toxicity, regional drug exposure and therapeutic efficacy might be significantly enhanced. We report herein a novel system that achieves complete hepatic venous isolation using a dual-balloon vena cava catheter that can be inserted percutaneously. This catheter is connected to a carbon filter in an extracorporeal venous bypass circuit to recover drug that is not absorbed by the liver after HAI. The hemodynamic response to this system was evaluated in six pigs. When the animals were placed on the extracorporeal circuit, we observed a 22% decrease in cardiac output that was well tolerated without significant change in blood pressure. When the filter was incorporated into the circuit, cardiac output was significantly reduced (50%); however, continuous infusion of phenylephrine rapidly normalized blood pressure, heart rate, cardiac output, and left ventricular filling pressures. Initial testing of chemofiltration efficacy was performed in four of the six animals, the remaining two animals being used only to assess hemodynamic response. One each of the four tested animals received either doxorubicin (3 or 9 mg/kg), mitomycin C (1 mg/kg), or cisplatin (1 mg/kg) by HAI. The filter removed over 90% of hepatic venous doxorubicin and mitomycin C and 65% of hepatic venous cisplatin. This feasibility study confirms that hepatic venous isolation with chemofiltration can significantly reduce systemic exposure to high-dose chemotherapeutic agents given by HAI.

Animals↗
PubMed1990

Evaluating the potential for powered mobility.

It has been 5 years since Chris was evaluated for a powered wheelchair, and she has had two occupational therapists and three physical therapists since the evaluation and training process began. It has been a long and arduous process, full of triumphs and setbacks. Chris's level of functional mobility, self-confidence, and ability to socialize, however, have increased dramatically as a result of her perseverance. The powered wheelchair, which she can control herself, has increased her ability to explore her environment and to master the increased activities made available through an expanded environment.

Adult↗
PubMed1986

An effective five-drug antiemetic combination for prevention of chemotherapy-related nausea and vomiting. Experience in eighty-four patients.

Antiemetics of known efficacy have been shown to block mainly one of three neurotransmitter receptors in the brain. A combination of antiemetics, designed specifically for outpatient use and consisting of metoclopramide, thiethylperazine, diphenhydramine, dexamethasone, and diazepam, is capable of blocking multiple sites in the emesis pathway. Eighty-four patients receiving highly emetic chemotherapy (85% received cisplatin) completed 200 trials of this five-drug combination using two similar regimens. Complete control (i.e., no nausea or vomiting) was achieved in 45% and two or fewer episodes of vomiting was experienced in 72% of these 200 trials. The mean number of vomiting episodes was 1.65, the median 1.0, and the range 0-15. Sedation was nearly universal, although no serious toxicity was encountered. Thus, this antiemetic combination designed for outpatient use proved highly effective in controlling nausea and vomiting associated with highly emetic anticancer treatment.

Adolescent↗
PubMed1982

The evolution of retinal vascularization in mammals. A comparison of vascular and avascular retinae.

There is a bimodal distribution of retinal thicknesses among mammals. Avascular retinae that are totally dependent on the choroid measure less than the theoretical oxygen diffusion maximum of 143 microns. Vascular retinae often measure twice this distance, but their avascular portions do not exceed the calculated diffusion maximum. Avascular retinae also show heavy glycogen deposition in the Müller cells of the inner retina, short photoreceptors, and lack both a tapetum and retinal taper. It is argued (1) that these anatomical features represent adaptations to their nutritional dependence on the choroid, and (2) that the phylogenetic distribution of avascularity (monotremes, many marsupials, and some of the primitive placental mammals) suggests that it is the ancestral condition in mammals. Finally, it is noted that some of the pathologic changes associated with retinal vascular damage in humans, namely thinning, gliosis, and glycogen deposition, are reminiscent of these ancestral patterns for coping with a limited blood supply.

Adult↗
PubMed1977

Antigenic shift of visna virus in persistently infected sheep.

Visna viruses isolated from persistently infected sheep were antigenically distinct from the plaque-purified virus used for inoculation. The selection of antigenic variants under antibody pressure, thought to occur in vivo, was reproduced in sheep cell cultures inoculated with plaque-purified visna virus and maintained in antibody. Antigenic shift may be a mechanism for persistence of virus in slow or recurrent viral infections.

Animals↗
PubMed1976

Experimental arthrogryposis caused by viral myopathy.

Immobilization of the embryo has been postulated to cause the joint deformities in arthrogryposis multiplex congenita (AMC). Experimental damage to the motor neurons or pharmacologic blockade of neuromuscular transmission has previously resulted in typical joint changes of AMC. In the present investigation, we have studied the effects of paralysis produced by a viral myopathy on joint development. Coxsackievirus A2 was injected intravenously into chick embryos on the seventh day of incubation. Within 48 hours, severe myositis and paralysis resulted. Electron microscopical and immunofluorescence techniques demonstrated virus in muscle cells. Within three to four days after infection, the muscle had virtually disappeared. Ankylosis of joints, corresponding to that seen in human AMC, occurred. This study shows that primary myopathy with paralysis can produce arthrogrypotic joint deformities. The possibility of a viral etiologic factor in some human cases of AMC should be considered.

Animals↗