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Biomedical subjects

J Stevens

Publications and source records attributed to J Stevens.

At least 19 recordsLinked to original sources
PubMed1992

Body mass index and body girths as predictors of mortality in black and white men.

Anthropometric measurements collected from black and white men in the 1960 (n = 946) and 1963 (n = 456) examinations of the Charleston Heart Study cohort (Charleston County, South Carolina) were examined as predictors of all cause and coronary heart disease mortality. Anthropometric measurements included body mass index, chest girth (at the third intercostal space), abdominal girth (at the umbilicus) and midarm circumference. Vital status of 98 percent of the cohort was determined through 1988. Body mass index was not associated with mortality in the white men; however, it was predictive of all cause and coronary heart disease mortality in the black men. Analyses conducted separately in the lower and upper range of body mass index in black men showed the adjusted relative hazard at the 50th versus the 10th percentile of body mass index was 0.54 for all cause mortality, but was not significant for coronary heart disease mortality; whereas the adjusted relative hazard for the 90th relative to the 50th percentile was 1.7 for coronary heart disease deaths, but not significant for deaths from all causes. The circumference measurements were not predictive of all cause or coronary heart disease mortality in the white men. In the black men, the adjusted relative hazard ratios for all cause mortality for the 85th relative to the 15th percentiles were 0.22 for midarm circumference and 2.0 for abdominal circumference.

Age Factors↗
PubMed1992

Somatic mutations in the neurofibromatosis 1 gene in human tumors.

The neurofibromatosis 1 (NF1) gene product, neurofibromin, contains a GTPase-activating protein (GAP)-related domain, or NF1 GRD, that is able to down-regulate p21ras by stimulating its intrinsic GTPase. Since p21ras.GTP is a major regulator of growth and differentiation, mutant neurofibromins resulting from somatic mutations in the NF1 gene might interfere with ras signaling pathways and contribute to the development of tumors. We describe an amino acid substitution in the NF1 GRD, altering Lys-1423, that has occurred in three tumor types: colon adenocarcinoma, myelodysplastic syndrome, and anaplastic astrocytoma, and in one family with neurofibromatosis 1. The GAP activity of the mutant NF1 GRD is 200- to 400-fold lower than that of wild type, whereas binding affinity is unaffected. Thus, germline mutations in NF1 that cause neurofibromatosis 1 can also occur in somatic cells and contribute to the development of sporadic tumors, including tumors not associated with neurofibromatosis 1.

Adenocarcinoma↗
PubMed1992

Characterization of human adenylate kinase 3 (AK3) cDNA and mapping of the AK3 pseudogene to an intron of the NF1 gene.

We have isolated cDNA clones for human adenylate kinase isozyme 3 (AK3) with a genomic probe from the neurofibromatosis type 1 (NF1) region. Three overlapping clones isolated from a human frontal-cortex cDNA library gave rise to a consensus sequence of 1.7 kb. The open reading frame identified in this sequence predicted a peptide of 223 residues. A database search revealed striking homology, about 58% amino acid sequence identity, between this predicted protein and bovine AK3. Human AK3 protein also showed significant homology to other members of the adenylate kinase family isolated from various species. Genomic Southern analysis suggested that multiple AK3 loci exist in the human genome, including one located in an intron of NF1 on chromosome 17. The chromosome-17 locus appears to be a processed pseudogene, since it is intronless and contains a polyadenylate tract; it nevertheless retains coding potential because the open reading frame is not impaired by any observed base substitutions.

Adenylate Kinase↗
PubMed1992

Treatment of displaced subcapital femoral fractures with total hip replacement.

A series of 46 patients with 46 displaced subcapital femoral fractures were treated with total hip replacements. Indications for treatment were age between 65 and 79 years, a mental test score of greater than 7/13 and mobility sufficient to allow the patient to leave the house at least once a week. The main complication was dislocation (9 per cent), which tended to occur early, and was associated with inexperience of the surgeon. The 6-month mortality was 9 per cent. The mean Harris score of 33 patients reviewed at 3 years was 83. Preoperative mobility was well maintained and there was no evidence of deep sepsis or loosening. We recommend that this method of treatment should be studied further in a prospective comparative fashion.

Aged↗
PubMed1992

P-32 bremsstrahlung SPECT helps assess intracavitary therapy.

A patient underwent intracavitary P-32 chromic phosphate therapy for a chest tumor. Tc-99m sulfur colloid instilled before the P-32 demonstrated uniform distribution of activity throughout the right pleural space, and the P-32 was immediately administered. Ten days later, SPECT imaging using bremsstrahlung radiation of the P-32 showed an unexpected loculation of the P-32. A subsequent chest CT scan demonstrated pleural infolding and fluid localization in the same area as the P-32, indicating that the bremsstrahlung SPECT study had, in fact, documented the final localization of the P-32, which was unexpected and different from the initial localization. The procedure used in this case may be of value in documenting the ultimate distribution of intracavitary P-32.

Aged↗
PubMed1992

Transdermal hyoscine with patient-controlled analgesia.

Transdermal hyoscine (Scopoderm TTS CIBA) was compared with placebo in 67 patients receiving postoperative analgesia via a patient-controlled analgesia system. All patients underwent an abdominal hysterectomy and had a standard anaesthetic. They were followed up in recovery and daily for 3 days postoperatively. Fewer patients in the hyoscine group suffered emetic sequelae in recovery and on the third postoperative day (p less than 0.05). The hyoscine group received half the number of supplementary antiemetic doses compared to placebo. However, despite transdermal hyoscine there was still a high (78%) incidence of nausea and vomiting. The only significant (p less than 0.05) increase in side effects attributable to hyoscine was a higher reported incidence of visual disturbance on the second day.

Adult↗
PubMed1992

Importance of routine measurement of HDL with total cholesterol in diabetic patients.

The prevalence of hypercholesterolaemia and the frequency of a reduced HDL-cholesterol (at different cholesterol concentrations) were evaluated in a group of 400 diabetic patients attending a single diabetic clinic. Despite regularly supervised diabetes, including dietary advice, over one quarter of the patients had a serum total cholesterol concentration greater than 6.5 mmol/l, while over a quarter of the non-insulin treated and one eighth of the insulin treated diabetic subjects had an HDL-cholesterol less than 0.9 mmol/l, with a greater prevalence in the males compared with the females. More than 60% of all the diabetic patients who had a reduced HDL-cholesterol less than 0.9 mmol/l also had a total cholesterol concentration less than 6.5 mmol/l. When the total/HDL-cholesterol ratio was calculated more non-insulin treated subjects had a value greater than 4.5 as compared with insulin treated diabetic patients. When comparisons were made between an age matched group of diabetic patients (n = 185) and a group of non-diabetic subjects attending for a health screen (n = 155), the frequencies of serum cholesterol concentrations greater than 5.2, 6.5, and 7.8 mmol/l were similar for both groups. Significantly greater numbers of diabetic patients had a reduced HDL-cholesterol less than 0.9 mmol/l (at any level of serum cholesterol) and a total/HDL cholesterol ratio greater than 4.5. This study has shown that the measurement of serum total cholesterol concentration alone will not characterize many subjects who are at risk of macrovascular complications due to a reduced HDL-cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Factors which influence mortality after subcapital hip fracture.

We report a prospective study of the influence of various factors on the six-month mortality of 531 patients with subcapital hip fractures. We performed univariate and multivariate analyses on the 403 patients treated surgically. The most significant predictors of the six-month mortality were dementia, postoperative chest infection, malignant neoplasia, old age and deep-wound infection, in that order. A simple test of mental ability was the most significant prognostic indicator and this test should be included in future studies of the management of hip fractures in the elderly.

Age Factors↗
PubMed1992

An interpractice visit study.

In general terms the tests are performed to monitor disease or therapy, to help in reaching or excluding a diagnosis, and to screen for significantly treatable abnormalities in apparently healthy people either in the population at large (as in hyperlipidaemia) or in a specific risk group, for example, relatives of colorectal cancer sufferers. The result of the test gives some indication of its value in diagnosis. A preponderance of abnormal results suggest that it adds little to the clinical acumen of the observer, while in the opposite situation a high proportion of normal results suggest that it is being wrongly applied. Where the purpose is monitoring, the survey should throw some light on the value and frequency of use of the test. How often does the discerning general practitioner order routine electrolytes, serum digoxin levels, thyroid function tests? And, more significantly, how often should this be done? General practitioners are the appropriate people who can find out and establish an accepted standard. In screening it should be possible to demonstrate both the value of the test in terms of detection rate (ratio of normal to abnormal results) and the efforts of an individual practitioner in preventive medicine expressed as proportion of total work load. Suitably expanded it could be extended to discover the proportion of the total population at risk that is being reached by screening. This writer believes that general practice lacks a published body of knowledge culled from its collective experience on which it can call when challenged by colleagues, government or even hostile barristers.(ABSTRACT TRUNCATED AT 250 WORDS)

Family Practice↗
PubMed1992

Quality of life improvements in CAPD patients treated with subcutaneously administered erythropoietin for anemia.

Twenty-two continuous ambulatory peritoneal dialysis (CAPD) patients, mean age 48 years, at 3 U.K. renal units were assessed with the Nottingham Health Profile (NHP) before and after treatment with recombinant human erythropoietin (r-HuEPO). Mean (SD) hemoglobin (Hb) at baseline was 7.5 (1.0) gm/dL and 10.8 (1.5) gm/dL at retest. There were significant improvements in energy (p less than 0.0001), social life (p less than 0.005), relationships at home (p less than 0.05) and leisure pursuits (p less than 0.05). Twelve patients, mean age 51 years, who had already completed more than 9 months on r-HuEPO treatment were reassessed to determine the changes sustained. Mean (SD) Hb at second retest was 12.8 (1.3) gm/dL. Improvement in energy continued to be significant, and emotional wellbeing showed further improvement. Problems with household tasks, which had not shown significant improvement at Test B, were now considerably reduced (p = 0.016). The study showed far-reaching benefits similar to those reported in hemodialysis patients, in a population with a higher mean age and higher potential coexisting illness or disability than most reported hemodialysis studies.

Activities of Daily Living↗
PubMed1992

Body mass index and body girths as predictors of mortality in black and white women.

BACKGROUND: The high prevalence of obesity in black women has been hypothesized to contribute to higher rates of coronary heart disease and total mortality. Investigators have recently refined the study of obesity by differentiating anatomic patterns of the physical location of adipose tissue on the body. We examined fat patterning as a predictor of mortality in black women. METHODS: Body mass index (BMI) and body girths were examined as predictors of all-cause and coronary heart disease mortality during 25 to 28 years of follow-up in black and white women in the Charleston Heart Study. RESULTS: The BMI was associated with all-cause and coronary heart disease mortality in white, but not black, women. After controlling for differences in BMI, the risk of all-cause mortality was greater in white women with larger chest and abdominal girths, while midarm girths were inversely associated with mortality. The hazard at the 85th percentile relative to the 15th percentile of abdomen/midarm ratio was 1.44 in models that included BMI, education, and smoking as covariates. In black women, the girths were not predictive of either all-cause or coronary heart disease mortality. CONCLUSIONS: The failure of BMI and fat patterning to predict mortality in black women challenges previously held assumptions regarding the role of overweight in the higher mortality experienced by black women.

Adult↗
PubMed1991

Identification and characterization of the familial adenomatous polyposis coli gene.

DNA from 61 unrelated patients with adenomatous polyposis coli (APC) was examined for mutations in three genes (DP1, SRP19, and DP2.5) located within a 100 kb region deleted in two of the patients. The intron-exon boundary sequences were defined for each of these genes, and single-strand conformation polymorphism analysis of exons from DP2.5 identified four mutations specific to APC patients. Each of two aberrant alleles contained a base substitution changing an amino acid to a stop codon in the predicted peptide; the other mutations were small deletions leading to frameshifts. Analysis of DNA from parents of one of these patients showed that his 2 bp deletion is a new mutation; furthermore, the mutation was transmitted to two of his children. These data have established that DP2.5 is the APC gene.

Adenomatous Polyposis Coli↗
PubMed1991

Identification of deletion mutations and three new genes at the familial polyposis locus.

Small (100-260 kb), nested deletions were characterized in DNA from two unrelated patients with familial adenomatous polyposis coli (APC). Three candidate genes located within the deleted region were ascertained and a previous candidate gene, MCC, was shown to be located outside the deleted region. One of the new genes contained sequence identical to SRP19, the gene coding for the 19 kd component of the ribosomal signal recognition particle. The second, provisionally designated DP1 (deleted in polyposis 1), was found to be transcribed in the same orientation as MCC. Two other cDNAs, DP2 and DP3, were found to overlap, forming a single gene, DP2.5, that is transcribed in the same orientation as SRP19.

Adenomatous Polyposis Coli↗
PubMed1991

Demonstration that bone mass is greater in black than in white children.

Osteoporosis and hip fractures are less common and bone mass is greater in black than in white women. To determine if bone mass is greater in black than in white children, bone mineral density (BMD) of the midradius by single-photon absorptiometry and BMD of the lumbar spine (L1-L4), trochanter, and femoral neck by dual-photon absorptiometry were measured in 20 black boys, 18 black girls, 33 white boys, and 35 white girls between the ages of 7 and 12 years. Mean age (10.4 +/- 0.3 versus 10.2 +/- 0.2 years) and body weight (39 +/- 2 versus 38 +/- 2 kg) in the blacks and whites, respectively, were not different in the two groups, and the ages and weights of the boys and girls were not different from each other. BMD were significantly greater in black than in white children at each site, in the black than in white boys at the trochanter and femoral neck, and in the black than in white girls at each site. In both races, BMD varied directly with age and body weight. Multivariate analysis showed that BMD were greater at the midradius, lumbar spine, trochanter, and femoral neck in the black than in the white children, that BMD of the lumbar spine was greater in the girls than in the boys, and that BMD of the trochanter and femoral neck were greater in the boys than in the girls. There were significant partial correlations between race and BMD and between BMD and body weight at each site, between sex and BMD at the lumbar spine, trochanter, and femoral neck, and between age and BMD at the midradius, trochanter, and femoral neck. Race, sex, age, and body weight together accounted for 49-66% of the variation in bone mass. Thus, BMD of the midradius, spine, and hip are greater in black than in white children, body weight and age are important determinants of bone mass, and some sex differences in bone mass are present at this age.

Absorptiometry, Photon↗
PubMed1991

Immobilized artificial membrane chromatography: rapid purification of functional membrane proteins.

A solid-phase membrane mimetic system, denoted as immobilized artificial membranes (IAM), has been developed and utilized as a novel high-performance liquid chromatography (HPLC) matrix for the first step in the rapid purification of functional membrane proteins. IAM phases consist of monolayers of amphiphilic membrane lipid molecules covalently bonded to a rigid silica particle. These monolayers of lipids have proved remarkably effective for the chromatography of biomolecules. Several cytochrome P450 isozymes, an extremely important family of hydrophobic membrane proteins with a labile heme catalytic center, have been partially purified in functional conformations from rat liver, kidney, and adrenal microsomes on IAM supports. Functionality of purified P450 and P450 reductase has been demonstrated by optical difference spectroscopy, by carbon monoxide binding, and by reconstitution of enzymatic activity in vitro. Other membrane proteins, including rat liver plasma membrane NADH oxidase and ferricyanide oxidoreductase have also been partially purified by IAM HPLC. The methods for purification of these proteins are described.

Adrenal Glands↗
PubMed1991

The ASNIS guided system for fixation of subcapital femoral fractures.

We report a prospective, consecutive series of 84 patients with 86 subcapital femoral fractures treated by internal fixation using ASNIS cannulated screws. At 1 year the clinical and radiological failure rate was 15 per cent. The failure rate was significantly influenced by age over 75 years, dementia, and fracture displacement (P less than 0.001).

Adult↗