PubMed HealthSearch

Biomedical subjects

J Townsend

Publications and source records attributed to J Townsend.

At least 19 recordsLinked to original sources

Accumulation of a Brazil nut albumin in seeds of transgenic canola results in enhanced levels of seed protein methionine.

We have increased the methionine content of the seed proteins of a commercial winter variety of canola by expressing a chimeric gene encoding a methionine-rich seed protein from Brazil nut in the seeds of transgenic plants. Transgenic canola seeds accumulate the heterologous methionine-rich protein at levels which range from 1.7% to 4.0% of the total seed protein and contain up to 33% more methionine. The precursor of the methionine-rich protein is processed correctly in the seeds, resulting in the appearance of the mature protein in the 2S protein fraction. The 2S methionine-rich protein accumulates in the transgenic seeds at the same time in development as the canola 11S seed proteins and disappears rapidly upon germination of the seed. The increase in methionine in the canola seed proteins should increase the value of canola meal which is used in animal feed formulations.

Gene Expression

Neuropathologic findings after liver transplantation.

Neuropathologic findings are described in 37 patients autopsied after one or more orthotopic liver transplants. Gross or microscopic lesions were observed in almost all patients, including anoxic-ischemic change, hemorrhages and/or infarcts, and opportunistic infections by fungi (most commonly Aspergillus) and rarely viruses (cytomegalovirus). Central pontine and extra-pontine myelinolysis was commonly observed, and appeared to result from severe multifactorial metabolic abnormalities in the perioperative period. Low-grade (microglial nodule) encephalitis without an obvious pathogen was often encountered. Common clinical neurologic abnormalities included encephalopathy, seizures (myoclonic, focal or generalized), obtundation and coma. These were found more commonly than focal findings, but clinical features in a given patient were not uniformly predictive of underlying neuropathologic change.

Brain Diseases

Comparison of condom breakage during human use with performance in laboratory testing.

This paper combines results from a study of the determinants of condom quality and use conducted by The Population Council in two countries in the Caribbean with results from a condom breakage study conducted by Family Health International (FHI) in the United States. The studies, conducted two years apart, compared the breakage rates of condoms from the same lot during human use to their performance in laboratory test results. Breakage rates of 12.9% for Barbados, 10.1% for St. Lucia and 6.7% for the United States compared to passing ASTM laboratory tests suggest that existing laboratory tests as used with the current pass/fail standards are either not sufficiently sensitive or not well-defined to reliably predict condom performance during human use. The study also suggests that user behaviors and practices may be a factor in condom breakage. If the condom is to be an effective method against unplanned pregnancy and STD/HIV infection, and if consumer confidence is to be retained, condom breakage during sexual intercourse must be reduced.

Barbados

Relation between cerebral oxidative metabolism following birth asphyxia, and neurodevelopmental outcome and brain growth at one year.

Studies of cerebral oxidative metabolism were carried out by phosphorous magnetic resonance spectroscopy during the first week of life in 52 infants with clinical and/or biochemical evidence of birth asphyxia. 15 infants died and the 37 survivors were assessed by a wide range of neurodevelopmental tests at one year of age. The minimum recorded values for cerebral phosphocreatine/inorganic phosphate concentration ratio (an index of oxidative metabolism) were related to outcome. The results showed a significant relation between the extent of derangement of oxidative metabolism and the severity of adverse outcomes, including death, neurodevelopmental impairment and reduced head growth.

Adenosine Triphosphate

Adolescent smokers seen in general practice: health, lifestyle, physical measurements, and response to antismoking advice.

OBJECTIVE: To compare physical, lifestyle, and health characteristics of adolescent smokers and non-smokers and their initial response to anti-smoking counselling. DESIGN: Adolescents aged 13, 15, and 17 years were identified from age-sex registers and invited by letter for a general practice health check. SETTING: Three general practices in the MRC general practice research framework. MAIN OUTCOME MEASURES: Blood pressure, body mass index, saliva cotinine concentration, peak flow rate, alcohol consumption, exercise, duration of sleep, and stated persistent health problems. RESULTS: 73% of the adolescents (491) attended for the health check. A total of 68 (14%) were regular smokers. By age 17 those who smoked regularly had a significantly lower systolic blood pressure than those who had never smoked regularly (by 6 mm Hg; p = 0.025) despite a significantly higher body mass index (by 1.5; p <0.001) [corrected]. Cotinine concentrations increased with smoking exposure, from 0.7 ng/ml when no family member smoked to 155 ng/ml in active smokers of six or more cigarettes a week. Significantly more regular smokers than never regular smokers drank greater than or equal to 8 g alcohol a day (chi 2 = 15.2 adjusted for age and sex p less than 0.001); regular smokers exercised less (1.0 hrs/week in boys and 0.8 hrs/week in girls v 3.4 hrs/week in boys and 2.2 hrs/week in girls; p less than 0.001) and slept less (8.0 hrs/night v 8.5 hrs/night at age 17; p less than 0.005). Persistent health problems, mostly asthma or allergic symptoms, were reported by 25% (17/68) of the smokers and 16% (60/381) of the non-smokers. Of the smokers given counselling, 60% (26/43) made an agreement with the practice doctor or nurse to give up smoking. CONCLUSION: General practice is an appropriate setting for adolescents to receive advice on healthy lifestyle, which should not focus solely on smoking.

Adolescent

Phenotypic profiles of language-impaired children based on genetic/family history.

Although etiological influences in developmental language impairment (dysphasia) are not well defined, a significant increase of family aggregation for the disorder has been reported. We report data from a large cohort of language-impaired (LI) children participating in the San Diego longitudinal study in which we examined whether children with or without positive family histories show different phenotypic profiles. Due to the longitudinal design of the study, questions pertaining to change over time are also addressed. Second, a subgroup of the most impaired children were reevaluated to obtain additional information pertaining to family history and phenotypic outcome. Approximately 70% of the LI children met criteria for inclusion as family history positive, with fathers reporting a history of language or learning problems one and a half to two times as frequently as mothers. LI children with or without a positive family history were not significantly different on language skills or IQ. However, subjects having a positive family history for developmental language/learning problems were significantly lower in socioeconomic status and were rated by parents and teachers as having more attention-related behavior problems than their family history negative counterparts. Similarly, family history positive LI children performed more poorly on standardized academic tests as well as on tests of auditory processing and attention.

Child

HIV-1 seropositivity and behavioral and sociological risks among homosexual and bisexual men in six Mexican cities.

We report on the epidemiology of sexual behaviors, HIV-1 seroprevalence, and condom use in gay and bisexual men in six Mexican cities in 1988 and test the extent to which variations in sexual behavior and sociological risks are responsible for variations in prevalence. Seroprevalence rates among samples in six cities ranged from 2% to 25%. In multiple logistic regression models controlling for city, insertive/receptive behavior (IRB), and meeting partners in bathhouses, the following were independently related to seropositivity (p less than 0.05): city, IRB, syphilis, sex with a person with AIDS, and meeting partners in bathouses. The independent risks associated with categories of IRB were no or almost no activity (odds ratio 1.0), only insertive (3.0), mostly insertive (4.9), mixed (6.0), mostly receptive (3.3), and only receptive (0.9). The condom use rate on last sexual encounter was 30%. The main sexual risk for HIV-1 infection is not exclusively receptive anal sex, but rather mixed behavior. This association may be explained by the infectious state of the partner pools. The sociologic risk variables (national and local partner pools) are better predictors of seroprevalence than behavioral variables, such as the number of partners or use of condoms. These results imply that more effective individual strategies for risk reduction are needed, including better knowledge concerning the risk status of partners.

Adolescent

Terminal cancer care and patients' preference for place of death: a prospective study.

OBJECTIVE: To assess the preference of terminally ill patients with cancer for their place of final care. DESIGN: Prospective study of randomly selected patients with cancer from hospital and the community who were expected to die within a year. Patients expected to live less than two months were interviewed at two week intervals; otherwise patients were interviewed monthly. Their main carer was interviewed three months after the patient's death. SETTING: District general hospital, hospices, and patients' homes. MAIN OUTCOME MEASURE: Stated preferred place of final care; actual place of death; reason for final hospital admission for those in hospital; community care provision required for home care. RESULTS: Of 98 patients approached, 84 (86%) agreed to be interviewed, of whom 70 (83%) died during the study and 59 (84%) stated a preferred place of final care: 34 (58%) wished to die at home given existing circumstances, 12 (20%) in hospital, 12 (20%) in a hospice, and one (2%) elsewhere. Their own home was the preferred place of care for 17 (94%) of the patients who died there, whereas of the 32 patients who died in hospital 22 (69%) had stated a preference to die elsewhere. Had circumstances been more favourable 67% (41) of patients would have preferred to die at home, 16% (10) in hospital, and 15% (9) in hospice. CONCLUSION: With a limited increase in community care 50% more patients with cancer could be supported to die at home, as they and their carers would prefer.

Consumer Behavior

Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment.

OBJECTIVE: To compare chiropractic and hospital outpatient treatment for managing low back pain of mechanical origin. DESIGN: Randomised controlled trial. Allocation to chiropractic or hospital management by minimisation to establish groups for analysis of results according to initial referral clinic, length of current episode, history, and severity of back pain. Patients were followed up for up two years. SETTING: Chiropractic and hospital outpatient clinics in 11 centres. PATIENTS: 741 Patients aged 18-65 who had no contraindications to manipulation and who had not been treated within the past month. INTERVENTIONS: Treatment at the discretion of the chiropractors, who used chiropractic manipulation in most patients, or of the hospital staff, who most commonly used Maitland mobilisation or manipulation, or both. MAIN OUTCOME MEASURES: Changes in the score on the Oswestry pain disability questionnaire and in the results of tests of straight leg raising and lumbar flexion. RESULTS: Chiropractic treatment was more effective than hospital outpatient management, mainly for patients with chronic or severe back pain. A benefit of about 7% points on the Oswestry scale was seen at two years. The benefit of chiropractic treatment became more evident throughout the follow up period. Secondary outcome measures also showed that chiropractic was more beneficial. CONCLUSIONS: For patients with low back pain in whom manipulation is not contraindicated chiropractic almost certainly confers worthwhile, long term benefit in comparison with hospital outpatient management. The benefit is seen mainly in those with chronic or severe pain. Introducing chiropractic into NHS practice should be considered.

Adolescent

Role of catecholamines in regulating ovine median eminence blood flow.

Blood flow was measured in the ovine median eminence and neural lobe before and after the intravenous infusion of dopamine (n = 7), the D1 agonist SKF 38393 (n = 4), the D2 agonist bromocriptine (n = 4), and the dopamine antagonist haloperidol (n = 5). It was also measured before and after the intracarotid infusion of dopamine into eight naive sheep and seven sheep pretreated with phenoxybenzamine. Radiolabeled microspheres were used to determine regional cerebral and regional neurohypophysial blood flows (RNHBF) in these 35 adult female sheep anesthetized with pentobarbital sodium. Samples for serum prolactin measurement by radioimmunoassay were obtained before and after drug infusion. Intravenous dopamine infusion did not change median eminence or neural lobe blood flow (RNHBF) but increased renal and choroid plexus blood flow. Intravenous haloperidol caused a significant fall in RNHBF and blood flow in choroid plexus, caudate nucleus, and kidneys. Intracarotid dopamine infusion decreased RNHBF but increased choroid plexus blood flow. RNHBF was significantly greater in the seven sheep pretreated with phenoxybenzamine than in the eight naive sheep. These findings do not support a role for dopamine in the regulation of median eminence blood flow. The last observation does add support to the hypothesis that norepinephrine or epinephrine interaction with alpha-receptors plays a role in the control of ovine median eminence blood flow and hence in the regulation of delivery of humoral messages from the brain to the anterior pituitary gland.

Animals

Relationship between neurodevelopmental status of very preterm infants at one and four years.

The neurodevelopmental status of 171 very preterm infants was assessed at one and four years of age. At one year 17 had major impairments and 14 had minor ones. At four years the numbers had increased to 25 with major and 25 with minor impairments. Infants with no impairments at one year had a 4 per cent probability of a major impairment at four years, whereas infants with a major impairment had a 94 per cent probability. Infants who later proved to have major neuromotor impairments had been accurately identified at one year, as had infants with sensorineural hearing-loss. Infants with minor impairments of tone and reflexes at one year did not develop cerebral movement disorder, but as a group their scores on tests of cognitive functioning were low. An additional group of infants with cognitive impairments was identified who were unimpaired at one year. The emergence of cognitive deficits largely accounted for the increase in impairments between one and four years.

Child, Preschool