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Biomedical subjects

M McMahon

Publications and source records attributed to M McMahon.

At least 127 records · Page 7Linked to original sources
PubMed1989

Comparison of the pattern of postprandial carbohydrate metabolism after ingestion of a glucose drink or a mixed meal.

To determine whether the postprandial pattern of carbohydrate metabolism differs after ingestion of an identical amount of glucose as either a drink or as a part of a mixed meal, normal subjects were studied on two occasions. On both occasions, hepatic and extrahepatic glucose metabolism were assessed using the dual isotope and forearm catheterization techniques as well as indirect calorimetry. Plasma glucose, insulin, and C-peptide concentrations and rate of systemic entry of ingested glucose all were lower (P less than 0.05) during the first 15 min after the mixed meal than after the glucose drink. The integrated C-peptide response was greater (P less than 0.05) after the mixed meal, whereas the integrated suppression of glucagon was greater (P less than 0.05) after the glucose drink. Despite these differences in circulating hormone concentrations, after the first 15 min, the rates of systemic entry of ingested glucose, endogenous glucose release, incorporation of carbon dioxide into glucose, and glucose and lipid oxidation as well as nonoxidative glucose storage were virtually the same after the mixed meal and the glucose drink. We conclude that the pattern of postprandial carbohydrate metabolism after ingestion of a glucose meal is remarkably similar to that after ingestion of a more traditional mixed meal. These data suggest that insights regarding the pattern of postprandial carbohydrate metabolism derived from previous studies employing only a glucose drink are likely to pertain to those observed when healthy individuals ingest a meal that contains protein and fat.

Adult↗
PubMed1989

Effects of basal insulin supplementation on disposition of mixed meal in obese patients with NIDDM.

Basal insulin supplementation has been used as a therapy for patients with non-insulin-dependent diabetes mellitus (NIDDM) who require insulin. To determine whether basal insulin supplementation in addition to lowering postabsorptive plasma glucose concentration also improves the postprandial pattern of glucose disposition, glucose metabolism after ingestion of a solid mixed meal was assessed in obese patients with NIDDM before and after treatment with ultralente and compared with glucose metabolism observed in nondiabetic subjects. Splanchnic uptake of ingested glucose clearance was assessed by including [2-3H]glucose (a tracer that only minimally cycles through glycogen) in a solid mixed meal. Postprandial gluconeogenesis was estimated by measuring the rate of incorporation of carbon dioxide into glucose. Net glucose and lipid oxidation were measured by indirect calorimetry. Both splanchnic uptake of ingested glucose (27 +/- 1 vs. 14 +/- 2 g) and postprandial hepatic glucose release (51 +/- 5 vs. 24 +/- 3 g) were greater (P less than .001) in diabetic than in nondiabetic subjects. Although the percentage of postprandial hepatic glucose release accounted for by glucose synthesis from bicarbonate was similar in the two groups (25 +/- 2 vs. 35 +/- 5%), the absolute rate was greater in the diabetic patients (13 +/- 1 vs. 8 +/- 1 g; P less than .05). Postprandial glucose oxidation and glucose disposal (measured either isotopically or by the forearm-catheterization technique) were similar in both groups. However, total lipid oxidation was increased in the diabetic patients. (P less than .05). Two weeks of basal insulin supplementation lowered fasting glucose concentrations (from 219 +/- 22 to 144 +/- 21 mg/dl; P less than .01) and integrated postprandial glycemic response (from 814 +/- 68 to 621 +/- 72 min.mg.ml-1) but not to normal. Although circulating insulin concentrations were two- to threefold greater (P less than .02) after 3 mo of basal insulin supplementation, the postprandial pattern of glucose metabolism remained essentially the same. Basal insulin supplementation decreased (P less than .05) both splanchnic uptake of ingested glucose and hepatic glucose release. The addition of a preprandial injection of soluble insulin to basal insulin supplementation further suppressed (P less than .05) postprandial hepatic glucose release, thereby further improving postprandial glucose tolerance. These studies indicate that initial splanchnic glucose clearance, hepatic glucose release, and new glucose synthesis, as well as extrahepatic substrate metabolism, are altered in NIDDM after ingestion of a mixed meal.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Glucose↗
PubMed1989

Personal adjustments and regimen compliance 1 year after myocardial infarction.

The relationship of attitudes and perceived beliefs of others to regimen compliance and personal psychologic and social adjustments of patients with myocardial infarction was investigated 1 year after the infarction. Eighty-one patients (39 in the experimental group, 42 in the control group) who participated in a prior study on the effect of a nursing intervention on regimen compliance, completed scales that assessed attitudes toward regimen prescriptions (diet, medications, activity, smoking, and stress response), perceived beliefs of others concerning compliance, personal adjustments, and regimen compliance. At 1 year, no differences were found between experimental and control groups for regimen compliance or personal adjustments. There was a significant decrease in mean scores for all variables from the time the patient was in the hospital to 30 days afterward, but no change at 1 year from the 30- or 60-day visit. At 1 year, attitudes were predictive of compliance for all regimen prescriptions. Perceived beliefs of others were predictive of diet, activity, and medication prescriptions.

Adaptation, Psychological↗
PubMed1988

Thiamine status, vitamin supplements and postoperative confusion.

In a prospective, randomized, controlled study an intravenous vitamin B complex and vitamin C preparation was administered pre- and post-operatively to 28 elderly patients with a fractured proximal femur and compared with 32 nonsupplemented postoperative controls. Vitamin supplementation significantly, though only transiently, improved postoperative thiamine status (P less than 0.001), but had no influence on mental state or outcome during the postsurgical period. Therefore, the use of parenteral vitamins for postoperative confusion cannot be justified on a routine basis.

Aged↗
PubMed1988

Radiographic performance of two different total hip cemented arthroplasties. A survivorship analysis.

Detailed serial radiographic analysis of the femoral and acetabular components of 367 Charnley (cobalt-chrome alloy) and 383 STH (titanium alloy) primary cemented total hip prostheses was conducted. The follow-up of the Charnley prosthesis ranged from 1 to 16 years (mean follow-up, 9 years), and for the STH from 1 to 11 years (mean follow-up, 80 months). Both single period and survivorship analyses were done to evaluate the radiographic performance. The analysis revealed that the curved STH prostheses' overall radiographic performance was less satisfactory than the Charnley prostheses. However, the STH with a straight stem had significantly better radiographic performance compared with the Charnley prostheses in all parameters except in the incidence of bone-cement radiolucent lines.

Adolescent↗
PubMed1986

Interferon-induced gene expression in wild-type and interferon-resistant human lymphoblastoid (Daudi) cells.

Interferon-induced gene expression was analyzed in wild-type and interferon-resistant Daudi cells. Two classes of alpha-interferon-induced mRNAs and proteins were observed: those that were similarly induced in both types of cell and those that were induced only in the wild-type cells. Furthermore, the level of c-myc mRNA decreased in the wild-type but not in the resistant cells. This differential control in the wild-type and resistant cells indicates that there must be either functionally distinct alpha-interferon receptors or more than one pathway leading to altered gene expression triggered by a single receptor.

Cell Division↗
PubMed1986

A multicase family study of rheumatoid arthritis in south west Ireland.

A study of 26 families with multiple cases of RA was conducted in South West Ireland. In 149 relatives examined, 67 cases of RA were identified. An analysis of affected sibling pairs and trios revealed significant linkage between HLA and RA (p less than 0.05). A high frequency of DR4 was observed in probands (80.7 per cent) and affected members (74.6 per cent) compared with controls (18 per cent). An elevated frequency of the haplotypes A2-B44-DR4 (19.2 per cent) and A2-Bw62-DR4 (5.7 per cent) was seen in the affected sample. HLA-Bw62 was at raised frequency in probands (19.2 per cent) compared with controls (9 per cent). The haplotype frequency of A2-B44-DR4 was raised in affected females and A2-Bw62-DR4 in affected males. A low haplotype frequency of A1-B8-DR3 was found in all RA subjects. Disease severity (clinical and radiological criteria) was associated with DR4, but this did not reach statistical significance. A high incidence of extra-articular features of RA was observed, with DR4 occurring in all cases of vasculitis (75 per cent of whom were DR4 homozygous).

Adult↗
PubMed1986

Life situations, health beliefs, and medical regimen adherence of patients with myocardial infarction.

One hundred twelve patients with MI were followed over a 6- to 9-month period to investigate their intentions and adherence behavior to a prescribed medical regimen in four life situations. The subjects with MI had strong intentions in the hospital to follow their prescription in all four situations, with the strongest for the home situation and the weakest for work. However, the actual adherence behaviors were less than the original intentions. The findings indicate the need for a review of the content of rehabilitation programs and consideration of the stage of recovery at which instructions are presented to patients rehabilitating from a MI. The intentions and adherence behaviors of subjects with MI were closely related to their perceptions of significant others' expectations. For the health team, this emphasizes the need to include significant others in patient rehabilitation.

Adult↗
PubMed1985

Human 2-5A synthetase: characterization of a novel cDNA and corresponding gene structure.

The enzyme 2-5A synthetase is induced in cultured cells in response to interferon (IFN) treatment. A lambda gt10 cDNA library of mRNA from IFN-induced Daudi lymphoblastoid cells was screened with oligonucleotide probes. Several overlapping cDNAs were isolated and shown to be derived from the human synthetase gene using filter selection and oocyte microinjection assays. The nucleotide sequence of one of these, cDNA 8-2, extended the 2-5A synthetase sequence already described 72 bp in the 5' direction but was found to differ significantly in coding sequence at the 3' end. The longest cDNA isolated (6-2) was approximately 1.4 kb. By Northern hybridization analysis single mRNAs of 1.7 kb were detected in Daudi and T98G (glioblastoma) cells. However, in HeLa cells, four mRNAs ranging in size from 1.5 to 3.5 kb were found, one of which differed at the 3' end. Analysis of both phage and cosmid genomic clones and comparison with genomic DNA indicate that there is a single gene for 2-5A synthetase, comprising at least six exons and five introns, which can undergo a novel form of alternative RNA processing depending on cell type.

2',5'-Oligoadenylate Synthetase↗
PubMed1985

Exercise and hypertension.

Hypertension is a major risk factor for atherosclerosis. In this article the authors review the use of physical activity as therapy for elevated blood pressure and explore the hemodynamic effects of exercise among patients with treated and untreated hypertension. Recommendations concerning the use of exercise in the management of hypertension are outlined.

Adolescent↗
PubMed1985

Uveal melanoma presenting after cataract extraction with intraocular lens implantation.

Four patients underwent cataract extraction with implantation of intraocular lenses. Preoperative ultrasonography did not include a comprehensive diagnostic B-scan analysis. Postoperative examination revealed uveal melanomas. The clinical presentations as well as the histopathologic findings of the two enucleated eyes are discussed. These cases emphasize the necessity for B-scan ultrasonography prior to cataract surgery when media opacity prevents adequate visualization of the fundus.

Aged↗