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Biomedical subjects

J Chase

Publications and source records attributed to J Chase.

At least 19 recordsLinked to original sources
PubMed1996

NMR studies of muscle glycogen synthesis in insulin-resistant offspring of parents with non-insulin-dependent diabetes mellitus immediately after glycogen-depleting exercise.

To examine the impact of insulin resistance on the insulin-dependent and insulin-independent portions of muscle glycogen synthesis during recovery from exercise, we studied eight young, lean, normoglycemic insulin-resistant (IR) offspring of individuals with non-insulin-dependent diabetes mellitus and eight age-weight matched control (CON) subjects after plantar flexion exercise that lowered muscle glycogen to approximately 25% of resting concentration. After approximately 20 min of exercise, intramuscular glucose 6-phosphate and glycogen were simultaneously monitored with 31P and 13C NMR spectroscopies. The postexercise rate of glycogen resynthesis was nonlinear. Glycogen synthesis rates during the initial insulin independent portion (0-1 hr of recovery) were similar in the two groups (IR, 15.5 +/- 1.3 mM/hr and CON, 15.8 +/- 1.7 mM/hr); however, over the next 4 hr, insulin-dependent glycogen synthesis was significantly reduced in the IR group [IR, 0.1 +/- 0.5 mM/hr and CON, 2.9 +/- 0.2 mM/hr; (P < or = 0.001)]. After exercise there was an initial rise in glucose 6-phosphate concentrations that returned to baseline after the first hour of recovery in both groups. In summary, we found that following muscle glycogen-depleting exercise, IR offspring of parents with non-insulin-dependent diabetes mellitus had (i) normal rates of muscle glycogen synthesis during the insulin-independent phase of recovery from exercise and (ii) severely diminished rates of muscle glycogen synthesis during the subsequent recovery period (2-5 hr), which has previously been shown to be insulin-dependent in normal CON subjects. These data provide evidence that exercise and insulin stimulate muscle glycogen synthesis in humans by different mechanisms and that in the IR subjects the early response to stimulation by exercise is normal.

Adult↗
PubMed1996

Information sources used in decision making: considerations for simulation development.

Simulation tasks, together with think aloud techniques are often used to research the cognitive processes individuals go through when making a decision or solving a problem. They have been utilised to a certain degree within nursing. A study was carried out to try and identify the sources of information nurses in acute medical and surgical wards used to make assessment judgements. A sample of 114 nurses were interviewed, and their responses analysed using content analysis. Four main sources of information were identified, with verbal interaction being the source of information most frequently mentioned by the subjects. The content of material presented in simulations is normally tested using techniques such as expert panels. However, this paper suggests that of equal importance may be the form of presentation or source of that information. It is suggested that in order to increase the validity of information obtained from simulation tasks, the form of presentation of information to the subject should also be considered.

Clinical Nursing Research↗
PubMed1995

The cognitive component of nursing assessment: an analysis.

This paper presents an analysis of the cognitive component of nursing assessment, complimenting the growth in knowledge of other important aspects of assessment. The purpose of the paper is to provide a framework for understanding how nurses structure assessment problems and the types of judgements they make. The thrust of the analysis is based on a comparison between nursing assessment and medical diagnosis, since the cognitive component and judgements formed in medical diagnosis have been more fully articulated. The results suggest that there may be similarities between the cognitive strategies used in nursing assessment and those used in medical diagnosis, particularly in relation to the gathering and organization of information. But the purpose of the information search appears to be different. In medical diagnosis the aim is to establish an explanation for the patient's presenting problem. In nursing assessment, on the other hand, the aim appears to be to provide an accurate picture of the patient's current condition or situation. The assessments formulated fit the definition of a judgement and, in common with medical diagnoses, include some form of prediction. Unlike the medical diagnoses, however, which usually remain stable throughout treatment, the assessments need to change as the patient's condition changes. The cognitive component of assessment has significant implications for nurse education and clinical practice. Further understanding of how nurses structure assessment problems and formulate judgements is therefore needed. The findings may also help to clarify the meaning of nursing diagnosis.

Cognition↗
PubMed1994

Hepatic arterial infusion of floxuridine, leucovorin, doxorubicin, and cisplatin for hepatocellular carcinoma: effects of hepatitis B and C viral infection on drug toxicity and patient survival.

PURPOSE: To conduct a pilot trial of hepatic arterial infusion (HAI) of floxuridine (FUDR), leucovorin, Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and cisplatin (FLAP) in nonresectable hepatocellular cancer (HCC) confined to the liver and assess the effects of hepatitis B (HBV) and hepatitis C (HCV) viral markers on toxicity, response to treatment, and patient survival. PATIENTS AND METHODS: Of 31 HCC patients, 13 were HBV- and HCV-nonreactive, and 18 had evidence of either current or prior HBV and/or HCV infection. Treatment was delivered through percutaneous hepatic arterial catheters, and Infusaid pumps (Shiley Infusaid, Norwood, MA) were placed in responding patients. Cisplatin (100 mg/m2) and Adriamycin (30 to 35 mg/m2) were administered on day 1, followed by a continuous 24-hour HAI of an admixture of floxuridine (60 mg/m2) and leucovorin (15 mg/m2) daily for 4 days. Treatment was repeated every 5 weeks. RESULTS: Twelve (41%) of 29 assessable patients had a partial response (PR), with a median time to disease progression of 13 months. Six (50%) of 12 HBV-negative (HBV-)/HCV-negative (HCV-) and six of 17 (35%) HBV-positive (HCV+) and/or HCV-positive (HCV+) patients achieved a PR. Eight patients have been maintained in remission for a median duration greater than 15.5 months. The median survival duration of all 31 patients was 15 months, 7.5 months among HBV+ and/or HCV+ patients, and significantly longer among hepatitis-non-reactive patients (P = .007). (A median has not yet been reached.) Granulocylopenia (< 0.1 x 10(3)/microL), thrombocytopenia (< 25 x 10(3)/microL), and hospitalizations for infectious complications were significantly more common among HBV-HCV-reactive than -nonreactive patients: 56%, 50%, and 67% versus 15%, 15%, and 8%, respectively (P < .05 for all). CONCLUSION: HAI of FLAP has induced long-term PR and has palliated extensive nonresectable HCC. Positive hepatitis serology appeared to increase bone marrow susceptibility to myelotoxic drugs. Conceivably, one or both viruses may have a direct inhibitory effect on bone marrow progenitors and thereby contribute to the observed myelotoxicity.

Aged↗
PubMed1993

Reduction of systemic drug exposure after hepatic arterial infusion of doxorubicin with complete hepatic venous isolation and extracorporeal chemofiltration.

BACKGROUND: Hepatic arterial infusion of doxorubicin has produced tumor response in hepatic malignancies; however, the limited success of these treatments is related in part to dose-limiting systemic toxicities. The purpose of this study was to determine whether a novel venous isolation-chemofiltration system could limit systemic exposure to doxorubicin after hepatic arterial infusion. METHODS: Doxorubicin (1 or 3 mg/kg) was infused in the hepatic arteries of domestic pigs after complete hepatic venous isolation was achieved with a dual-balloon vena cava catheter. The hepatic vein effluent was pumped through an extracorporeal carbon chemofiltration circuit. Doxorubicin levels were measured in prefilter (hepatic vein), postfilter, and systemic serum at intervals up to 1 hour after drug infusion. RESULTS: Complete hepatic venous isolation with extracorporeal chemofiltration significantly reduced (> 90%) the postfilter and systemic levels of doxorubicin compared with prefilter levels (p < 0.01). At the time animals were killed 7 days after infusion of doxorubicin (3 mg/kg), tissue levels of doxorubicin in the liver showed a 16-fold increase compared with levels in the heart (p < 0.01). CONCLUSIONS: For chemotherapeutic drugs like doxorubicin with a low first-pass extraction by the liver, the novel system described herein achieved significant reduction in systemic drug exposure. This system will allow dose intensification of doxorubicin administered by hepatic arterial infusion to treat hepatic malignancies.

Alanine Transaminase↗
PubMed1992

Biosynthesis and endocrine control of the production of the German cockroach sex pheromone 3,11-dimethylnonacosan-2-one.

The biosynthesis and endocrine regulation of sex pheromone production in the female German cockroach (Blattella germanica) were determined. Radio-TLC and radio-GLC were used to demonstrate the metabolism of 3,11-dimethylnonacosane, a major cuticular lipid component, to the corresponding alkan-2-ol and methyl ketone. [11,12-3H2]-3,11-Dimethylnonacosan-2-ol was efficiently metabolized to the methyl ketone, and radio-GLC showed that the methyl ketone product from both experiments was coeluted with a methyl ketone standard. A comparison of the metabolism of the labeled dimethylalkane and dimethylalkan-2-ol by age and sex showed that both males and females from day 1 through day 9 after adult emergence readily metabolized the alcohol to the corresponding methyl ketone, whereas only females of 5-9 days postemergence efficiently converted the labeled dimethylalkane to the corresponding methyl ketone. Application of the juvenile hormone analog hydroprene induced significant increases in the conversion of the labeled hydrocarbon to the methyl ketone in starved adult females as well as in females fed a protein-free diet, conditions under which endogenous juvenile hormone biosynthesis is nearly undetectable. These data show that the methyl ketone sex pheromone is formed by the hydroxylation and oxidation of the 3,11-dimethylalkane at the 2 position, show that the age- and sex-specific step in this process is the conversion of 3,11-dimethylnonacosane to 3,11-dimethylnonacosan-2-ol, and provide evidence that juvenile hormone regulates sex pheromone production in the German cockroach.

Animals↗
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↗