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Biomedical subjects

R Gregg

Publications and source records attributed to R Gregg.

36 records · Page 2Linked to original sources
PubMed1993

Exclusion of malignant hyperthermia susceptibility (MHS) from a putative MHS2 locus on chromosome 17q and of the alpha 1, beta 1, and gamma subunits of the dihydropyridine receptor calcium channel as candidates for the molecular defect.

Malignant hyperthermia (MH) is a potentially lethal pharmacogenetic disease with autosomal dominant inheritance triggered by exposure to commonly used inhalational anaesthetics or depolarising muscle relaxants. A MHS locus has been identified on human chromosome 19q12-q13.2 and the gene for the skeletal muscle calcium release channel of sarcoplasmic reticulum (ryanodine receptor) (RYR1) is considered a candidate for the molecular defect. However, MH has been shown to be genetically heterogeneous, and in the ensuing search for other MHS genes, a locus on chromosome 17q has been proposed, and the gene for the adult muscle sodium channel (SCN4A) was suggested as a candidate. We performed linkage studies using polymorphic microsatellite markers for subunits of the skeletal muscle dihydropyridine (DHP) receptor, CACNL1A3 mapped to chromosome 1q, as well as C-ACNLB1 and CACNLG, the latter two localised on chromosome 17q11.2-q24 in proximity to the proposed MHS2 and the SCN4A loci, and we also included markers for the loci D17S250, D17S579, NM23 (NME1), GH1, and SCN4A from that region. Our results exclude the alpha 1, beta 1 and gamma subunit of the DHP receptor as well as the SCN4A locus from that region. Our results exclude the alpha 1, beta 1, and gamma subunit of the DHP receptor as well as the SCN4A locus as candidates for the molecular defect in MHS for these pedigrees where also the RYR1 on chromosome 19q13.1 has been excluded. A multipoint analysis excludes the disease from the entire 84 cM interval containing the proposed MHS locus on chromosome 17q.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1993

"Choice" as a double-edged sword: information, guilt and mother-blaming in a high-tech age.

Women in the United States experience pregnancy in the context of more medical interventions than ever before. Procreative technologies can enhance both the range of choices for women and the possibility of greater social control of women's choices. Sometimes procreative technologies are a matter of routine, not choice. New developments in genomic research and prenatal diagnosis may lead to the routinization of further medical interventions in pregnancy. Women increasingly may lose the freedom to choose not to use prenatal tests or the information they provide. This article is drawn from a study of women's experiences of pregnancy. The women's stories and two examples of recent news reports demonstrate some of the pressures women face as they attempt to make choices about pregnancy and motherhood. The examples indicate that women face subtle and overt pressures on their "choices."

Choice Behavior↗
PubMed1991

Use of femoral venous catheters in critically ill adults: prospective study.

OBJECTIVE: To determine the frequency of clinically important complications of femoral venous catheters. DESIGN: Prospective survey of major and minor complications. SETTING: A mixed medical/surgical ICU in a university hospital. PATIENTS: One hundred twenty-three patients admitted to the ICU who underwent femoral venous catheterization over a 2-yr period. MEASUREMENTS AND MAIN RESULTS: There were 150 catheters inserted in 123 patients for a mean duration of 6.4 days. There were no major complications including catheter-related sepsis. Minor complications consisted of arterial puncture (9.3%), local bleeding (10%), and local inflammation (4.7%). Critical care fellows had a significantly lower rate (6%) of insertion complications than interns or medical students (16%). We did not specifically look at the frequency of deep venous thrombosis. CONCLUSIONS: Femoral venous catheterization offers an alternative site of insertion to the subclavian and jugular veins for central venous access in the critically ill. The occurrence rate of clinically important complications is acceptably low.

Adult↗
PubMed1991

Jamaican patients' understanding of diabetes mellitus.

Ambulant and hospitalized patients with diabetes mellitus were interviewed by two trained interviewers to obtain information about their knowledge of the illness and the communication they had received about it. Sixty to seventy per cent of patients claimed that no explanation about the illness was given to them at the time of diagnosis. This poor communication occurred in both public and private medical services. Fifty-seven per cent of the patients scored no more than the 50th percentile on the knowledge rating score, reflecting that patients' knowledge of the illness was in general poor. The hospitalized patients did learn about the illness while there, but still claimed that they learnt nothing. These data are examined in the context of the nature of the doctor-patient communication style and effect. Jamaican diabetic patients need to be better informed about their illness; despite short patient-physician contact time, an effort to explain the nature of the illness at the time of diagnosis would be worthwhile. This will need subsequent assessment and reinforcement by involving a team approach.

Ambulatory Care↗
PubMed1989

Binding of thyroxine to human plasma low density lipoprotein through specific interaction with apolipoprotein B (apoB-100).

Human plasma low density lipoprotein (LDL), which binds 0.2% of plasma T4, was shown to interact with the hormone through its protein moiety, apolipoprotein B-100. LDL and LDL2, the major subfraction of LDL, were found to have 3 equivalent binding sites for T4 with Ka = 2.5 x 10(6) M-1. Photoaffinity labeling of LDL with inner ring-labeled [125I]T4, followed by SDS-PAGE or agarose-SDS-PAGE of the labeled products, revealed that apoB-100 and its proteolytic cleavage products, apoB-74 and apoB-26, bound [125I]T4. In the presence of 1 or 10 microM T4, labeling was decreased in 7 separate experiments by 40-53% or 65-86%, respectively, consistent with a Ka of approximately 10(6) M-1. Binding of T4 to apoB-100 associated with VLDL was also demonstrated by photoaffinity labeling. The observed thyroid hormone binding property of lipid-complexed apoB-100 and the knowledge that receptors for the apolipoprotein exist in various tissues suggest a possible physiological role in thyroid hormone transport.

Apolipoproteins B↗
PubMed1982

Circulatory, plasma catecholamine, cortisol, lipid, and psychological responses to a real-life stress (third molar extractions): effects of diazepam sedation and of inclusion of epinephrine with the local anesthetic.

We studied the circulatory, psychological, plasma catecholamine, cortisol, and lipid responses to a real-life stress--third molar extractions--in 21 patients and the effects of sedation with intravenous diazepam and of inclusion of epinephrine with the local anesthetic. Across all patients, the surgery was associated with significantly increased heart rate (25%), systolic blood pressure (13%) and cardiac output--as indicated using impedance cardiography (34%)--without a significant change in diastolic blood pressure. Plasma norepinephrine increased by 60% during the surgery in nonsedated patients. Diazepam sedation abolished the norepinephrine response to the surgery, without significantly affecting the heart rate or systolic pressure responses. Receipt of epinephrine with the local anesthetic resulted in a fivefold increase in mean plasma epinephrine 5 min after the injection, as well as increased cardiac output. The direct effect of epinephrine accounted for the cardiac output increase observed during the surgery. The results suggest the participation of the sympathetic nervous system in producing the circulatory responses to dental surgery. The elimination of sympathetic recruitment by diazepam-induced sedation, however, without concomitant reductions in heart rate or systolic pressure responses, suggests that other systems besides the sympathetic nervous system influence the circulatory response to this real-life stress.

Adolescent↗
PubMed1979

The association of pyloric antral tissue levels of 5-hydroxytryptamine and restraint stress ulceration in the rat.

To determine the possible role of 5-hydroxytryptamine (5-HT) in the formation of restraint ulcerations, we investigated the relationship among mucosal tissue levels of 5-HT, vagotomy, and restraint ulcerations. Three murine experimental groups and one control group were used to compare the ulcerogenic effects of restraint with and without prior vagotomy. Ulcers were graded as to frequency, size, and hemorrhage on a 0-4+ scale. 5HT was measured in the gastric mucosa of each animal. Restraint caused significant ulcerations. The mean tissue level of 5-HT was significantly higher in the group with marked ulcerations (p less than 0.001). Our data suggest an increased cellular production of 5-HT during the development of the restraint ulcers. Vagotomy protected the animals against restraint ulcerations without depleting the baseline levels of 5-HT. Previous experiments have shown that urine levels of 5-hydroxyindoleacetic acid (5-HIAA) increase during the restraint period. Thus, increased tissue and urine levels of 5-HT appear to coincide with the development of restraint stress ulcers in the rat. Accordingly, if the coincidence occurs in humans, the measurement of urinary levels of 5-HIAA may be an indirect means of determining those patients at high risk for the development of stress ulcers.

Animals↗
PubMed1976

Effect of acute uremia on triglyceride kinetics in the rat.

Plasma triglyceride (TG) levesl were elevated 24 hr after the production of acute uremia in rats. The effect of acute uremia on TG production rate was estimated by determining the rate of TG accumulation following Triton WR 1339 inhibition of lipoprotein removal, by measuring hepatic TG secretion rate during in situ liver perfusion, and by quantifying hepatocyte very low density lipoprotein content with the electron microscope. The results of all three of these approaches indicated that TG synthesis and secretion were decreased in acute uremia, suggesting that the associated increase in plasma TG levels had to result from a removal defect. This hypothesis was tested directly by injecting pre-labeled very low density lipoprotein TG into acutely uremic and control rats, and measuring its rate of disappearance from plasma. The t1/2 of removal in acutely uremic rats was found to be approximately twice that of control, confirming the hypothesis that the rise in plasma TG levels in acute uremia is due to a defect in removal of TG from plasma.

Acute Disease↗
PubMedDate not supplied

Low back pain following epidural blood patch.

A patient underwent outpatient knee arthroscopy with spinal anesthesia administered at the patient's request. The patient was discharged after a 3-hour recovery period. Three days later, the patient returned because of a headache that had begun the evening after surgery and progressively worsened. Treatment with caffeine and hydration for presumed postdural puncture headache resulted in relief for approximately 1 hour. An epidural blood patch was then performed and relieved symptoms for 3 hours until backache began and worsened over the next 7 hours. Computed axial tomography showed epidural air. After symptomatic treatment and observation overnight, the patient was released, and follow-up by telephone was planned. For 2 days, symptoms persisted. Therapy with aspirin 600 mg 4 times daily resulted in acute and significant relief. The backache resolved after 1 week. A review of the literature on backache following epidural blood patch is presented.

Anesthesia, Spinal↗
PubMedDate not supplied

Promoting health in young people.

This article discusses aspects of health that might affect young people and ways in which nurses can promote healthy living and support this group of clients during a potential period of anxiety.

Adolescent↗