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Biomedical subjects

J Stevens

Publications and source records attributed to J Stevens.

At least 181 records · Page 10Linked to original sources
PubMed1995

Who cares about care in nursing education?

Many sources indicate that nurses have a negative view of work with ageing patients. Wide-spread stereotypes concerning old age no doubt exercise influences in the formation of nurses' attitudes. The research reported here suggests that nurses' negative attitudes towards the elderly are consolidated rather than dissolved in the course of their training. The reasons for this may not, in fact, lie in the nature of the gerontology components (small as they usually are) of the curriculum. Rather, the course (or the "professional socialisation" process) as a whole appears to carry messages that devalue personal care duties--contra the prestige of activities attached to all levels of medical technology. The ageing patient, often requiring much hands-on (the body) care is thus located well outside areas of work which are perceived by nurses to include clearly focused professional pathways.

Adult↗
PubMed1995

Diaphragmatic agenesis as a distinct clinical entity.

Anatomically, diaphragmatic agenesis (DA) is the most extreme form of congenital diaphragmatic defect, but clinically it has not been defined separately from Bochdalek's hernia (BH). Between 1986 and 1992, the authors treated 55 neonates who had diaphragmatic defects. Forty-eight of these cases presented within 24 hours of birth. Seventeen of these neonates (35.4%) were found to have DA; the other 31 (64.6%) had BH. There were no significant differences in maternal age, gestational age, gender ratio, birth weight, and incidence of coexisting congenital anomalies between the two groups. However, neonates with DA differed significantly from those with BH with respect to incidence of antenatal diagnosis (76.4% v 12.5%, P = .0004), mean Apgar scores at 1 (4.1 +/- 2.0 v 5.7 +/- 2.3; P = .034) and 5 (5.5 +/- 2.7 v 7.6 +/- 2.2; P = .016) minutes, mean duration of preoperative stabilization (2.8 +/- 2.0 v 2.1 +/- 1.9 days; P = .044), and postoperative respiratory support (27.7 +/- 13.6 v 9.3 +/- 8.0 days; P = .002). Complications occurred in all seven DA survivors (100%) and in only four (19.0%) of the 21 BH survivors (P = .0008). The long-term survival rate was significantly lower for neonates with DA (29.4% v 64.5%; P = .04). Diaphragmatic agenesis is a distinct clinical entity; its unique short- and long-term problems require careful management.

Adult↗
PubMed1995

Genetic diversity and population structure of Trypanosoma brucei: clonality versus sexuality.

Genomic fingerprinting by arbitrarily primed PCR was used to analyze the genetic variability among 59 Trypanosoma brucei stocks representing the three T. brucei subspecies isolated from various hosts and different countries in Africa. 14 oligonucleotide primers revealed 355 polymorphic binary characters which were used for phenetic and phylogenetic analysis and to perform recombination tests exploring the linkage disequilibrium in the sample. There was good concordance between arbitrarily primed PCR polymorphisms and isoenzyme data previously collected for many of the same strains [1]. However, the arbitrarily primed PCR typing was more discerning than multilocus enzyme electrophoresis typing. Phenetic and phylogenetic analysis using arbitrarily primed PCR markers did not confirm T. brucei brucei and T. brucei rhodesiense as separate subspecies, but T. brucei gambiense group I was monophyletic, confirming this group as suitable for the subspecies status. With this exception, there were no clear lineages among the sample, other than clustering of East African stocks and clustering of West African stocks. Some features of the phylogenetic analysis suggested that the population structure was not strictly clonal though recombination tests showed linkage disequilibrium, even in the absence of repeated genotypes. While genotypes appear stable enough for tracking in applied studies, sexuality will impact at the evolutionary time scale, and may be more frequent under some ecological conditions. The arbitrarily primed PCR approach should be an effective and simple approach to follow epidemics and to quantify the role of sexuality in T. brucei populations.

Africa↗
PubMed1995

Chromosome 14 linked familial Alzheimer's disease. A clinico-pathological study of a single pedigree.

The clinical features of three affected members of a British pedigree with familial Alzheimer's disease are presented. This pedigree is one of six included in an earlier study which demonstrated linkage to chromosome 14. The individuals were investigated clinically and neuropsychologically, using both PET and MRI over a 4-year period. Further information from three deceased individuals was obtained, including histopathological confirmation of Alzheimer's disease in one case which came to autopsy. The mean age at onset for this family was 43 years. Neurological examination revealed myoclonic jerks in all cases, and one patient was documented to have seizures. Strikingly similar neuropsychological profiles were observed, characterized by an initial memory deficit with early dyscalculia and an impairment in speech production with relative absence of anomia. All individuals showed mild degrees of cerebral atrophy and two individuals had periventricular white matter lesions. PET scanning using [18F]fluorodeoxyglucose showed parieto-temporal hypometabolism in all cases and the two severely affected patients with speech production changes had additional left-sided frontal hypometabolism involving Broca's area. The least affected case initially had a more asymmetrical reduction in metabolism in the left inferior temporal and supramarginal gyri; a follow-up scan showed that this deficit had become bilateral and more severe. These clinical and neuroimaging features have not been previously reported in chromosome 14 linked pedigrees; the phenotypic variability between families suggests allelic heterogeneity at the chromosome 14 locus.

Adult↗
PubMed1995

The utilisation and economic evaluation of antibiotics prescribed in primary care.

This was an observational study of efficacy and resource utilisation over three years in a cohort of 917 patients who received at least one prescription for an oral antibiotic between January and March 1989 in a large rural primary care health centre in Tayside, Scotland. Three thousand, six hundred and sixty three prescriptions were issued (2286 to females) for; 1502 upper respiratory tract infections, 419 lower respiratory tract infections, 441 urinary tract infections, 177 skin and soft tissue infections, 97 gynaecological infections, 103 cases of acne and 71 other infections. Excluding acne, 14% of infections required more than one antibiotic to achieve a successful outcome. The highest success rates for antibiotics were amoxycillin (92%) and penicillin V (92%) in upper respiratory tract infections, erythromycin (90%) in lower respiratory tract infections and co-trimoxazole (83%) in urinary tract infections. The most cost-effective antibiotics were penicillin V for upper respiratory tract infection, erythromycin for lower respiratory tract infection and co-trimoxazole for urinary tract infection. Varying the value placed on general practitioners' time did not change the rank order of antibiotic cost-effectiveness. The efficacy and cost-effectiveness of the treatment of acute infections in primary care varies considerably with the antibiotic used as first choice. More expensive antibiotics might be justified in cost-effectiveness terms if they had high cure rates in clinical practice.

Adolescent↗
PubMed1995

Mutational analysis of the redox-sensitive transcriptional regulator OxyR: regions important for DNA binding and multimerization.

OxyR is a LysR-type transcriptional regulator which negatively regulates its own expression and positively regulates the expression of proteins important for the defense against hydrogen peroxide in Escherichia coli and Salmonella typhimurium. Using random mutagenesis, we isolated six nonrepressing OxyR mutants that were impaired in DNA binding. Five of the mutations causing the DNA binding defect mapped near the N-terminal helix-turn-helix motif conserved among the LysR family members, confirming that this region is a DNA binding domain in OxyR. The sixth nonrepressing mutant (with E-225 changed to K [E225K]) was found to be predominantly dimeric, in contrast to the tetrameric wild-type protein, suggesting that a C-terminal region defined by the E225K mutation is involved in multimerization.

Amino Acid Sequence↗
PubMed1995

Differential influence of arachidonic vs. eicosapentaenoic acid on experimental pulmonary hypertension.

The impact of the 2- and 3-series prostanoid precursors arachidonic acid (AA) and eicosapentaenoic acid (EPA) on experimental pulmonary hypertension was investigated. The model of buffer-perfused rabbit lungs was stimulated by infusion of Escherichia coli hemolysin (HlyA), which is known to provoke sustained thromboxane (Tx)-mediated pulmonary hypertension. Release of di- and trienoic Tx into the recirculating perfusate was quantified by a post-high-performance liquid chromatography enzyme-linked immunosorbent assay technique. HlyA at 0.08 hemolytic unit/ml caused a sustained rise in pulmonary arterial pressure (PAP; maximum increase 14 +/- 2 mmHg) accompanied by progressive TxB2 liberation (maximum perfusate concn 33 +/- 4 pg/ml, baseline < 2 pg/ml). Between 5 and 30 nM, AA provoked a transient monophasic rise in PAP (maximum pressor response 1.5-15 mmHg) and concomitant TxB2 release (peak concn 2-30 pg/ml). Simultaneous administration of HlyA and AA exhibited additive effects with regard to mediator release and pressor responses. EPA at 200-2,000 nM caused a transient rise in PAP similar to that provoked by 5-30 nM AA (maximum pressor response 3-18 mmHg). This was accompanied by liberation of TxB2 (peak concn 16 +/- 5 and 28 +/- 4 pg/ml after 1,000 and 2,000 nM EPA) and TxB3 (peak concn 9 +/- 4 and 30 +/- 3 pg/ml). Combined application of HlyA and EPA resulted in approximate addition of the TxB2 release reaction to each single compound, and TxB3 liberation more than doubled (maximum concn 59 +/- 12 pg/ml). The pressor responses to HlyA-EPA (200-2,000 nM) did not, however, surpass those to HlyA-AA (5-30 nM).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Combined intraoperative radiation and perioperative chemotherapy for unresectable cancers of the pancreas.

PURPOSE: To evaluate the effectiveness of combined intraoperative radiation therapy (IORT) and perioperative chemotherapy in the management of unresectable pancreatic cancer. MATERIALS AND METHODS: Forty-nine patients with localized unresectable adenocarcinoma of the pancreas were treated in a multimodality program of initial IORT and perioperative chemotherapy (fluorouracil [5-FU]/leucovorin) followed by combined external-beam radiation (40 to 55 Gy) and continued chemotherapy. Patients were evaluated for toxicity, pattern of failure, and survival. The follow-up times of these patients range from a minimum of 12 months to a maximum of 62 months, with a median of 28 months. RESULTS: The incidence of perioperative mortality was 0%. Early postsurgical morbidity (grade 3/4) was observed in seven of 49 patients (14%) and late treatment-related morbidity (grade 3/4) in eight of 43 patients (19%) alive beyond 6 months. Morbidity was primarily gastrointestinal (GI), with no hematologic toxicities observed. The median survival time in the total group of patients is 16 months, with a 2-year survival rate of 22% and a 4-year survival rate of 7%. Freedom from local progression of disease was achieved in 71% of patients. CONCLUSION: The patients who undergo IORT with electrons and treated with perioperative chemotherapy (5-FU leucovorin) followed by additional external-beam radiation and chemotherapy appear to have improved survival, with few early or late complications. Dose escalation of external-beam radiation and chemotherapy may further improve local control of disease and survival of patients.

Actuarial Analysis↗
PubMed1995

Increased axon regeneration in astrocytes grown in the presence of proteoglycan synthesis inhibitors.

We have recently reported that the critical difference between astrocytic cell lines that are good or poor promoters of axon growth lies in the extracellular matrix. We demonstrated that much of this difference between matrix produced by permissive and non-permissive cell lines could be ascribed to one or more dermatan/keratan sulphate proteoglycans and that these proteoglycans are able to block the neurite-promoting effect of laminin. These proteoglycans are also produced by cultures of primary astrocytes. In the present study, we have demonstrated that treatment of both astrocytic cell lines and primary astrocytes with inhibitors of proteoglycan synthesis, beta-D-xylosides and sodium chlorate, can strongly influence the axon growth promoting properties of both matrix and whole cells. Dorsal root ganglia grown on matrix or in conditioned medium from cultures treated with beta-D-xylosides or sodium chlorate had twice as many axons and the axons grew to twice the length as in control cultures. Following treatment of Neu7 cells with proteoglycan synthesis inhibitors there was also a significant reduction in the ability of Neu7 conditioned medium to block the neurite-promoting effect of laminin. Dorsal root ganglia grown on Neu7 cells treated with sodium chlorate extended 2 to 3 times the number of axons for approximately 300 mm longer distance than on control cultures. Treatment of Neu7 cells with beta-D-xylosides, however, did not make the cells less inhibitory to axon growth. We have also examined the effects of proteoglycan synthesis inhibitors on three-dimensional primary astrocyte cultures, which closely mimic the in vivo effects of astrocytes on axon growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Zidovudine plus interferon-alpha versus zidovudine alone in HIV-infected symptomatic or asymptomatic persons with CD4+ cell counts > 150 x 10(6)/L: results of the Zidon trial. Zidon Study Group.

OBJECTIVE: To evaluate the efficacy and safety of zidovudine (ZDV) and lymphoblastoid interferon (IFN)-alpha combination therapy compared with ZDV monotherapy in HIV-infected subjects with CD4+ cell counts between 150 and 500 x 10(6)/l. DESIGN: Open, randomized controlled trial with subjects stratified by the Centers for Disease Control and Prevention (CDC) 1986 classification of HIV disease (group II/III or IV). The study was amended to a sequential design in February 1992 to allow interim analyses to be conducted. SETTING: Outpatient clinics in 45 hospitals in Europe, Australia and Canada. PARTICIPANTS: A total of 402 previously untreated subjects with symptomatic HIV infection (CDC group IV) and CD4+ count 150-500 x 10(6)/l or asymptomatic HIV infection (CDC group II/III) with CD4+ count 150-350 x 10(6)/l. INTERVENTIONS: ZDV 250 mg twice daily with or without 3 MU subcutaneous injections of lymphoblastoid IFN-alpha three times per week. MAIN OUTCOME MEASURES: Time to development of a study endpoint defined as: progression from CDC group II/III to group IV, group IV non-AIDS to AIDS, or group IV AIDS to a second AIDS-defining condition; also CD4+ count to < 50 x 10(6)/l on two occasions at least 1 month apart or HIV-related death irrespective of CDC group on entry. RESULTS: There was no reduction in the rate of disease progression for patients receiving ZDV plus IFN-alpha compared with patients receiving ZDV alone. No major differences between the groups were seen for CD4+ counts or percentages, or p24 antigenaemia. In a subset of 70 patients, a similar proportion from both dose groups showed evidence of ZDV resistance after 48 weeks of treatment. More adverse experiences were seen in the ZDV/IFN-alpha group. CONCLUSIONS: Combination therapy with low dose lymphoblastoid IFN-alpha and ZDV revealed no clinical benefit compared with ZDV monotherapy.

Adolescent↗
PubMed1994

Body size perceptions and eating attitudes in elderly men.

The majority of studies on eating attitudes, dieting and body size perceptions have focused on young adults and women. This study examined these attitudes in 334 black and white men, ages 55 to 98 years, who were members of the Charleston Heart Study cohort. Associations of the eating attitude variable with race, education and weight status were examined. Eighty-two percent of the overweight white men studied had dieted to lose weight, whereas only 49% of slimmer white men had dieted. In contrast, overweight black men did not diet more than slimmer black men. Overall black men dieted less than white men (37% reported dieting). Black men who were high school graduates were 1.3 times more likely to have dieted than were less educated black men. Overweight white men were over twice as likely as slimmer white men to feel guilty after overeating. This difference was not found in overweight versus slimmer black men. Education was not associated with measured body mass index (BMI) or perceived or ideal body size. However, there were some racial differences in these variables. White men preferred to be slightly thinner than black men (ideal BMI 25.6 vs. 26.1 kg/m2), and the difference between actual and desired BMI was 0.6 kg/m2 greater in white than in black men. These results indicate that effects of race and weight status on eating restraint and body size perceptions seen in younger subjects and in women are also present, at least to some degree, in elderly men.

Aged↗
PubMed1994

Diaphragmatic agenesis as a distinct clinical entity.

Anatomically, diaphragmatic agenesis (DA) represents the most extreme form of congenital diaphragmatic defects, but clinically it has not been defined separately from Bochalek's hernia (BH). Between 1986 and 1992, the authors treated 55 neonates who had diaphragmatic defects. Forty-eight of them presented within 24 hours of birth and comprised the study group. Seventeen neonates (35.4%) were found to have DA; the other 31 (64.6%) had BH. There were no differences in the maternal age, gestation course, gender ratio, birth weight, or incidence of co-existing congenital anomalies between the two groups. However, there were significant differences with respect to the incidence of antenatal diagnosis (76.4% for DA patients v 12.5% for BH patients; P = .0004), mean (+/- SD) Apgar scores at 1 (4.1 +/- 2.0 v 5.7 +/- 2.3; P = .034) and 5 minutes (5.5 +/- 2.7 v 7.6 +/- 2.2; P = .016), mean duration of preoperative stabilization (2.8 +/- 2.0 v 2.1 +/- 1.9 days; P = .044) and mean duration of postoperative respiratory support (27.7 +/- 13.6 v 9.3 +/- 8.0 days; P = .002). Complications occurred in all seven survivors of DA and in only four (19.0%) of 21 survivors of BH (P = .0008). The neonates with DA had a significantly poorer long-term survival rates (29.4% v 64.5%; P = .04). Diaphragmatic agenesis is a distinct clinical entity; its unique short-term and long-term problems require careful management.

Diaphragm↗
PubMed1994

Ultrasonic carotid artery plaque structure and the risk of cerebral infarction on computed tomography.

PURPOSE: The North American and the European Symptomatic Carotid Endarterectomy Trial investigators reported a conclusive benefit of carotid endarterectomy for patients with symptomatic 70% to 99% internal carotid artery (ICA) stenosis. However, it has been suggested that plaque structure may be an even more important factor in producing stroke than the degree of stenosis. The aim of this study was to test the hypothesis that the ultrasonic characteristics of carotid artery plaques were closely related to symptoms and to the prevalence of cerebral infarcts on computed tomography (CT). METHODS: One hundred five carotid artery plaques causing greater than 70% stenosis in the ICA in 83 consecutive patients who underwent brain CT were characterized into four ultrasonic types: echolucent plaques, predominantly echolucent plaques, predominantly echogenic plaques, and echogenic plaques. Patients with permanent neurologic deficit were excluded. RESULTS: There was a significant ipsilateral association between type 1 plaques and symptomatic hemispheres (p < 0.002). Twenty-six of the 105 cerebral hemispheres assessed by CT had infarcts. There was an increased incidence of brain infarcts in type I plaques (37%) compared with 18% in types II, III, and IV combined (p < 0.02). CONCLUSION: Our results support the hypothesis that echolucent plaques are more frequently associated with symptoms and cerebral infarctions and provide further evidence that these plaques are unstable and tend to embolize. Studies on the natural history of asymptomatic carotid artery stenosis should investigate whether plaque characterization could identify a high-risk group.

Arteriosclerosis↗
PubMed1994

Black women have smaller abdominal girths than white women of the same relative weight.

Anthropometric measurements were compared in 312 white and 242 black women (mean age 54) who were participants in the Charleston Heart Study. Body mass index (BMI) was greater in black women (27.8 kg/m2) than in white women (24.7 kg/m2) as were body circumferences. However, when the girth measurements were adjusted for BMI, some racial differences were reversed. Age, smoking and BMI-adjusted abdominal girth was smaller in the black women than in the white women (88.9 cm vs 92.2 cm). The ratio of abdomen to midarm circumference was larger in white women than black women (3.24 vs 3.09), and could be interpreted to indicate a less central fat pattern in the black women. This conclusion should be viewed with caution since circumference measurements, though often used in epidemiologic research, do not differentiate between subcutaneous fat and visceral fat.

Abdomen↗
PubMed1994

A physical map and candidate genes in the BRCA1 region on chromosome 17q12-21.

We have constructed a physical map of a 4 cM region on chromosome 17q12-21 that contains the hereditary breast and ovarian cancer gene BRCA1. The map comprises a contig of 137 overlapping yeast artificial chromosomes and P1 clones, onto which we have placed 112 PCR markers. We have localized more than 20 genes on this map, ten of which had not been mapped to the region previously, and have isolated 30 cDNA clones representing partial sequences of as yet unidentified genes. Two genes that lie within a narrow region defined by meiotic breakpoints in BRCA1 patients have been sequenced in breast cancer patients without revealing any deleterious mutations. These new reagents should facilitate the identification of BRCA1.

Autoantigens↗
PubMed1994

Unexpected isolation of Bordetella pertussis from a blood culture.

Bordetella pertussis was isolated from a culture of blood from a 31-year-old man with Wegener's granulomatosis. The organism was detected with the BACTEC 9240 system after 6 days of incubation and was confirmed as B. pertussis by the Centers for Disease Control and Prevention. To our knowledge, this is the first published report of the recovery of B. pertussis from blood.

Adult↗
PubMed1994

Heightened airway responsiveness in normal female children compared with adults.

Studies have suggested that airway responsiveness declines with maturation; however, studies comparing infants, children, and adults are confounded by differences in size as well as maturation. Therefore, to determine whether maturation has a significant affect on airway responsiveness, we compared normal female children (n = 9; mean age = 13.6 yr) and adults (n = 7; mean age = 42.4 yr) who were matched for body size. Bronchial challenge tests were performed with increasing methacholine concentrations to a maximum of 30 mg/ml. At baseline, there were no significant differences between the two groups in lung volumes (TGV, RV, TLC) or flow-volume curves (FEV1, average forced expiratory flow rate between 25% and 75% of the vital capacity [FEF25-75], FVC). All subjects but one adolescent completed the challenge (30 mg/ml). The children had a greater percentage decline from baseline in FEV1 than the adults (17 versus 7%, p < 0.03). The percentage decline in FEF25-75 was greater for the children than for the adults, but the difference was not statistically significant (35 versus 20%, p < 0.10). Compared with the children, the adults more often demonstrated a plateau in their dose-response curves for FEV1 (22 versus 86%) and for FEF25-75 (33 versus 100%). We conclude that normal female children have a greater airway responsiveness to inhaled methacholine than do adults, and that this difference is not related to baseline lung size, airway caliber, or delivered methacholine dose.

Adolescent↗