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Biomedical subjects

J Collins

Publications and source records attributed to J Collins.

At least 361 records · Page 20Linked to original sources
PubMed1985

Parathyroid hormone and the altered vascular response to norepinephrine in uremia.

Patients with chronic renal failure manifest reduced pressor response to norepinephrine (NE); this abnormality is at least partly responsible for the autonomic nervous system dysfunction observed in these patients. Since uremia is associated with increased levels of parathyroid hormone (PTH) and since PTH blunts the pressor effect of NE most likely via activation of prostaglandins, we have studied the relationship between blood levels of PTH and the reduced pressor response to NE in 17 uremic patients and we examined the effect of treatment with indomethacin on the response to NE in 9 uremic and 5 normal subjects. There was a significant negative correlation (r = -0.63, p less than 0.01) between the changes in blood pressure and the blood levels of PTH in uremic patients. Treatment with indomethacin was followed by significant improvement or normalization of the pressor response to NE in uremic patients. These data are consistent with the notion that the decreased pressor response to NE in uremia is due to increased production of prostaglandins induced by excess PTH and provide a therapeutic tool for the treatment of some of the manifestations of autonomic nervous system dysfunction in uremia.

Adult↗
PubMed1985

Indium-111 oxine platelet survival in dogs: effect of doxorubicin and Dacron grafts.

The cytotoxic chemotherapeutic agent doxorubicin was found to acutely decrease platelet survival times in beagle dogs as determined using platelets labeled with [111In]oxine. Recovery was rapid, with platelet survival times returning to normal within 3 wk of cessation of treatment. Doxorubicin (1.5 mg/kg i.v. every 3 wk for a total of four doses) also delayed the return of platelet survival times to normal when given to beagle dogs following placement of thoracoabdominal aortic Dacron grafts. It is not known whether or not this may have clinical significance.

Animals↗
PubMed1985

Structure of the penicillin acylase gene from Escherichia coli: a periplasmic enzyme that undergoes multiple proteolytic processing.

Penicillin acylase is processed from a 90-kD precursor through the cleavage of a leader peptide and two further endopeptidase cleavages to yield an enzyme that contains a 22-kD (or 23-kD) and a 65-kD subunit. The endopeptidase cleavages require an intact carboxy terminus. This type of processing appears to be unique for a prokaryotic enzyme, having its most closely related analog in the synthesis and processing of preproinsulin and other eukaryotic hormones.

Amidohydrolases↗
PubMed1984

Synthesis and secretion of serum phosphorylcholine-binding protein by rat hepatocytes.

The incorporation of [1-14C]glucosamine into rat serum phosphorylcholine-binding protein in an isolated rat hepatocyte system was used to demonstrate the synthesis and secretion of this protein by the liver. The hepatocytes after incubating with colchicine resulted in an increased intracellular accumulation of phosphorylcholine-binding protein and less of the synthesized phosphorylcholine-binding protein was secreted into the medium. The synthesis of phosphorylcholine-binding protein was found to be significantly impaired when the hepatocytes were incubated with tunicamycin. The radiolabelled phosphorylcholine-binding protein co-eluted with exogenous phosphorylcholine-binding protein as a homogeneous peak by affinity chromatography. The identity of the radiolabelled phosphorylcholine-binding protein was further established by quantitative immunoprecipitation, polyacrylamide gel electrophoresis and isoelectric focusing.

Animals↗
PubMed1984

Community adjustment among older depressives.

Depression is the most common emotional disorder of later life, yet there is much confusion and clinical speculation about it. Adjustment of later-life depressives after psychiatric treatment is virtually an unknown area, as is the phenomenon of depression itself with this population. This study addressed these two issues. Community adjustment of younger and older clinically depressed patients after treatment was monitored. Also, adjustment differences in self and other ratings were compared between the two age groups. Results show that there are no significant differences in posttreatment adjustment ratings between the age groups. In addition, it was found that older depressives with a longer history of depression adjust less well than expected. Lastly, older depressives (relative to younger ones), particularly neurotic ones, show the following pattern of adjustment: Less alienation, less vigor, less confidence in skills, poorer work history, less abuse of alcohol or drugs, more social constriction, more agitation, and fewer household management skills.

Aged↗
PubMed1984

Older age research non-responders: an inpatient "profile".

Examined the differences between older research non-responders and older completers and between older research non-responders and younger ones. As part of a large cooperative Veterans Administration study, a sample of 619 older non-responders were compared to 964 older completers and also to 4,731 younger non-responders on basic demographic and treatment factors, as well as on self-rated adjustment dimensions. Among other factors, results show that older non-responders tend to be substance abusers, to be "loners," but have equal or better adjustment ratings than older completers; and among other variables, older non-responders tend to be "first timers" in psychiatric hospitals, to have greater treatment expectations, and to rate themselves with better adjustment in many areas relative to younger non-responders.

Age Factors↗
PubMed1984

Novel cluster of alpha-interferon gene sequences in a placental cosmid DNA library.

A human cosmid library was constructed and probed with a human alpha interferon (IFN-alpha) cDNA clone. One clone giving a strong hybridizing signal was isolated and characterized. The cosmid DNA insert represents a section of the human genome containing three regions of IFN-alpha-like sequences. The DNA was characterized with restriction endonuclease mapping, thereby allowing comparison to similar linkage groups reported recently and determination of homologous regions on the known physical map. The three IFN-alpha-like sequences were analyzed by a partial sequence analysis. Mapping and sequence data establish this section as a not-yet-described cluster of IFN-alpha sequences in the human genome; however, a part of the section matches to some degree to a previously described genomic region. The region described here could represent genetic polymorphism or a duplicated segment.

Base Sequence↗
PubMed1984

Mitoxantrone treatment in advanced breast cancer.

Half of our patients presenting with breast cancer will eventually require cytotoxic chemotherapy. In searching for an effective drug with low toxicity, many new drugs have been investigated. Seventeen patients with advanced breast cancer were treated with mitoxantrone, an analogue of adriamycin. The response rate was 44% (CR 6% + PR 38%). Side effects were fewer than those normally anticipated for most cytotoxic chemotherapy in that only two patients suffered hair loss and three nausea and vomiting. There was, however, significant bone marrow depression with granulocytopenia and two patients died of septicaemia following treatment. Cardiac toxicity occurred in two patients: of these, both had prior treatment with adriamycin, and one had prior radiotherapy to the chest wall. Both of these patients died.

Adult↗
PubMed1984

Gas transport during oscillatory flow in a network of branching tubes.

A transport coefficient was measured for a range of oscillatory flow conditions in a branching network of tubes. Measurements were made both across the first generation of a three-generation network and the second generation of a four-generation network. The results for these two series of tests were similar, indicating that there was no significant effect due to the system boundaries. The results are cast in terms of an effective axial diffusion coefficient of the form (Formula: see text) where kappa is the molecular diffusivity, Vt is the local stroke volume (cc); and f is the oscillation frequency (Hz). These results are compared to those obtained by other investigators in branching systems of similar geometry. At low frequency, this result is found to be in approximate agreement with the steady flow result of Scherer, et al. [15]. This expression differs from the oscillatory flow results of Tarbell, et al. [19] for liquids, primarily in terms of the effects of oscillation frequency.

Animals↗
PubMed1984

Prescriptive authority for nurse practitioners: a comparative study of professional attitudes.

We assessed the attitudes of Wyoming physicians, pharmacists, nurses, and nurse practitioners about granting prescriptive authority to nurse practitioners. Support for the issue was mixed, with physicians expressing the strongest disagreement. All groups supported limitation of authority to a specific drug formulary, collaborative regulation, and mandatory certification and continuing education if prescriptive authority is granted to nurse practitioners.

Attitude of Health Personnel↗
PubMed1984

Pharmacological evaluation of intravenous delivery of 5-bromodeoxyuridine to patients with brain tumors.

Previously, 5-bromodeoxyuridine (BrdUrd) has been shown to be an effective radiosensitizing agent in rapidly dividing cells. As part of a Phase I/II study to evaluate BrdUrd as a radiosensitizer in gliomas, the pharmacology was studied in eight patients. BrdUrd was infused using an i.v. route as a 12-hr constant infusion each day for as long as 14 days. BrdUrd steady-state arterial levels are described for three different infusional rates: 1.6 mumol/sq m/min (350 mg/sq m/12 hr) produced a steady-state arterial level of 0.7 microM; 3.2 mumol/sq m/min (700 mg/sq m/12 hr) resulted in 2.1 microM; 5.9 mumol/sq m/min (650 mg/sq m/6 hr) showed a level of 3.9 microM. Because of myelosuppression, the highest tolerable dose for this intermittent long-term infusional therapy with BrdUrd appears to be 700 mg/sq m/12 hr. Contrary to the nonlinear pharmacokinetics of thymidine, 5-fluorouracil, and 5-fluorodeoxyuridine described previously, BrdUrd shows linear behavior in the range studied. BrdUrd still has promise as a radiosensitizer for gliomas in humans, but an alternative means of safe delivery into the carotid artery is needed. Because of an estimated 11- to 16-fold-higher local concentration, use of the intraarterial route could deliver optimum levels of BrdUrd to the tumor with minimal systemic toxicity.

Brain Neoplasms↗
PubMed1983

The effect of early meconium evacuation on early-onset hyperbilirubinemia.

Delayed passage of meconium has been associated with hyperbilirubinemia. To determine if early evacuation of meconium is effective in reducing total serum bilirubin level, 84 term healthy neonates were randomly assigned to a suppository group or a nonsuppository group. Use of suppositories resulted in earlier evacuation of meconium as measured by the appearance of transitional stool. No significant effect was noted, however, on total serum bilirubin levels in the first three days of life. Routine use of suppositories to decrease total serum bilirubin level cannot be recommended for term healthy neonates.

Bilirubin↗
PubMed1983

Community adjustment of older schizophrenics.

Community adjustment among older schizophrenics is a virtually unresearched area. This study addressed two questions related to this problem: Does the community adjustment of older schizophrenics differ from that of younger schizophrenics?, and Do "older" old schizophrenics differ from "younger" old schizophrenics? Patients from 79 psychiatric wards across the country completed a self-rating adjustment scale within 5 days of admission to the hospital and again 3 months after discharge. Significant others rated these patients for adjustment also. For the first analysis two groups were selected: Those patients diagnosed schizophrenic and at least 55 years of age and those below the age of 55. A second analysis divided patients into "younger" old (between 55 and 60) and "older" old (greater than 60). Results show that older schizophrenics adjust about as well as those younger on self-ratings, but less well when rated by others. Also, "older" old schizophrenics adjust better than the "younger" old in both self- and significant other ratings. These findings are discussed.

Age Factors↗
PubMed1983

Mode of action of dl-norgestrel and ethinylestradiol combination in postcoital contraception. III. Effect of preovulatory administration following the luteinizing hormone surge on ovarian steroidogenesis.

A combination of 1.0 mg dl-norgestrel and 0.1 mg ethinylestradiol was administered orally at 18 hours after the detection of luteinizing hormone rise and again at 30 hours in five healthy volunteers with normal menstrual cycles. The effects on ovarian function were studied by comparing the daily serum levels of progesterone (P), 17 alpha-hydroxyprogesterone, and estradiol (E2) measured in a control (placebo) cycle with those in two consecutive treatment cycles. Treatment did not alter the steroid levels in one subject. P was suppressed in one or both treatment cycles of four subjects. E2 was suppressed in both treatment cycles of one subject and produced widely fluctuating patterns in another. The hormonal patterns in the two consecutive treatment cycles of the same individual were similar in all but one instance, where only the P level in the second treatment cycle was diminished. These results showed that this treatment can elicit steroidogenic responses of varying degrees and duration. The contraceptive action may lie in the altered P and/or E2 level at certain points in the menstrual cycle.

17-alpha-Hydroxyprogesterone↗