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Biomedical subjects

J Bowen

Publications and source records attributed to J Bowen.

At least 55 records · Page 3Linked to original sources
PubMed1998

MR imaging and proton MR spectroscopy in A-to-G substitution at nucleotide position 3243 of leucine transfer RNA.

MR imaging of the brain in a 38-year-old woman with maternally inherited diabetes and deafness (MIDD) showed extensive subcortical and basal ganglia high signal intensity on T2-weighted studies though she was neurologically asymptomatic. High-signal-intensity changes were also seen in the basal ganglia on T1-weighted studies. Proton MR spectroscopy showed increased lactate, an increased choline/creatine ratio, and a decreased N-acetylaspartate/creatine ratio. Our observations suggest that patients with MIDD may have subclinical neurologic dysfunction identifiable by proton MR spectroscopy.

Adult↗
PubMed1997

Cholelithiasis in early infancy

This report describes three children, age range 7 weeks to 5 months, who presented with obstructive jaundice secondary to gallstones. Previous Escherichia coli septicaemia and frusemide therapy were predisposing risk factors in two of the patients. All three were successfully treated with cholecystectomy and exploration of the common bile duct.

Journal Article↗
PubMed1997

Progression to dementia in patients with isolated memory loss.

BACKGROUND: The diagnosis of dementia requires both memory loss and at least one other type of cognitive impairment. The natural history of patients with severe memory loss but no other type of cognitive impairment is poorly understood. We studied progression to dementia in patients with isolated memory loss. METHODS: From a registry of 811 patients with cognitive complaints, 21 patients with severe isolated memory loss of unknown cause were identified and followed up for a mean of 48 months. A comparison group of 198 patients on the same register was identified with newly recognised cognitive complaints but without dementia or isolated memory loss (mean follow-up 31 months). We did a range of neuropsychological tests at intake. FINDINGS: During follow-up, 48% (n = 10) of patients with isolated memory loss-developed dementia compared with 18% (n = 36) of the comparison group. Life-table analysis showed the mean times to a diagnosis of dementia was 3.77 years (95% CI 2.99-4.56) and 5.96 years (5.60-6.31), respectively (p = 0.01). The neuropsychological tests did not predict which patients would progress to dementia. INTERPRETATION: Patients with severe isolated memory loss have an increased risk of developing dementia and should be closely followed-up.

Adult↗
PubMed1997

Pion radiation for high grade astrocytoma: results of a randomized study.

PURPOSE: This study attempted to compare within a randomized study the outcome of pion radiation therapy vs. conventional photon irradiation for the treatment of high-grade astrocytomas. METHODS AND MATERIALS: Eighty-four patients were randomized to pion therapy (33-34.5 Gy pi), or conventional photon irradiation (60 Gy). Entry criteria included astrocytoma (modified Kernohan high Grade 3 or Grade 4), age 18-70, Karnofsky performance status (KPS) > or = 50, ability to start irradiation within 30 days of surgery, unifocal tumor, and treatment volume < 850 cc. The high-dose volume in both arms was computed tomography enhancement plus a 2-cm margin. The study was designed with the power to detect a twofold difference between arms. RESULTS: Eighty-one eligible patients were equally balanced for all known prognostic variables. Pion patients started radiation 7 days earlier on average than photon patients, but other treatment-related variables did not differ. There were no significant differences for either early or late radiation toxicity between treatment arms. Actuarial survival analysis shows no differences in terms of time to local recurrence or overall survival where median survival was 10 months in both arms (p = 0.22). The physician-assessed KPS and patient-assessed quality of life (QOL) measurements were generally maintained within 10 percentage points until shortly before tumor recurrence. There was no apparent difference in the serial KPS or QOL scores between treatment arms. CONCLUSION: In contrast to high linear energy transfer (LET) therapy for central nervous system tumors, such as neutron or neon therapy, the safety of pion therapy, which is of intermediate LET, has been reaffirmed. However, this study has demonstrated no therapeutic gain for pion therapy of glioblastoma.

Adult↗
PubMed1997

Rare pulmonary manifestations of tuberous sclerosis in children.

Tuberous sclerosis is one of the rare neurocutaneous syndromes and may involve organs other than skin and brain. Pulmonary involvement is uncommon and predominantly affects women of childbearing age. Those affected present with dyspnea or spontaneous pneumothorax from cystic or fibrous degeneration of the lung. Males are affected very rarely. This paper describes another manifestation of pulmonary involvement in tuberous sclerosis, namely, recurrent intrapleural cysts in a young boy.

Child↗
PubMed1997

One-stage neonatal pull-through to treat Hirschsprung's disease.

INTRODUCTION: Traditionally Hirschsprung's disease has been treated by a three-stage procedure. This approach has been associated with stoma problems, three episodes of hospitalization, and a theoretical disadvantage, because of the delayed passage of feces via the rectum, in controlling defecation. The aim of this study was to assess the results of one-stage neonatal pull-through for the treatment of Hirschsprung's disease. METHODS: This was a 10-year retrospective review of all patients treated with a neonatal pull-through for Hirschsprung's disease. Information was obtained from the patients' records. All descriptive data are expressed as mean +/- standard deviation. RESULTS: Fifty-one patients were treated in the 10-year period studied. The mean gestational age was 39.6 +/- 1.7 weeks, weight was 3.3 +/- 0.54 kg, with 76% being boys. The surgery was performed at 10.3 +/- 5.8 days of age. A Swenson procedure was carried out in 38 patients and a Soave in 13. The extent of the disease was rectosigmoid in 39, and the remaining were sigmoid, descending colon, and total colonic. The mean length of the surgery was 181 +/- 40 minutes. Blood transfusions were required in 13 patients with a mean volume of 55 mL given. The complications observed were: an anastomotic leak in two cases, requiring laparotomy and colostomy (both in patients with Down's syndrome), and wound infection in three cases. There were two delayed deaths both associated with other congenital anomalies. In total, three patients required further surgery; two had colostomies, one requiring a redo pull-through and one had an ileostomy for enterocolitis. The total length of hospital stay was 20.4 +/- 11.2 days. Mean follow-up was 3.73 +/- 2.9 years. In 21 patients the follow-up was greater than 4 years and in this group none were totally incontinent. Four patients complained of soiling at least once a week, and 17 had normal bowel control. CONCLUSION: Hirschsprung's disease can be successfully treated in the neonatal period with a one-stage pull-through. The short- and long-term results are as good as those with the three-stage procedure, with the child usually benefitting by not having a stoma and a shorter hospital stay.

Anal Canal↗
PubMed1997

Germline and somatic transformation of mating Tetrahymena thermophila by particle bombardment.

Mating Tetrahymena thermophila were bombarded with ribosomal DNA-coated particles at various times in development. Both macronuclear and micronuclear transformants were recovered. Optimal developmental stages for transformation occurred during meiosis for the micronucleus and during anlagen formation for the macronucleus. Evidence is given for transient retention of the introduced plasmid. Genetic and molecular tests confirmed that sexually heritable transformation was associated with integration at the homologous site in the recipient micronuclear chromosome.

Animals↗
PubMed1997

Protective immunity against herpes simplex virus (HSV) type 1 following oral administration of recombinant Salmonella typhimurium vaccine strains expressing HSV antigens.

Salmonella typhimurium strains expressing foreign antigens of various pathogens are capable of eliciting antigen-specific humoral and cellular immune responses. Attenuated S. typhimurium strain chi4550 (delta(cya) delta(crp) delta(asd)) was used as an expression vector for herpes simplex virus (HSV) antigens. Genes encoding glycoprotein D (gD) and the immediate-early protein ICP27 of HSV-1 were cloned and expressed in plasmid pYA292 (asd+) and subsequently placed into chi4550. Following two oral immunizations, the protective efficacy of recombinant strains against zosteriform challenge with HSV-1 was measured in 3-4-week-old BALB/c mice. Levels of protection observed were 77% with the ICP27 construct but only 31% with the gD construct. Zosteriform protection correlates with a CD4+-mediated delayed-type hypersensitivity (DTH) reaction against HSV. Accordingly, significant DTH was observed only in mice immunized orally with the S. typhimurium ICP27 construct. ELISA analysis of antigen-specific humoral responses failed to detect serum antibody responses following oral administration although recombinant S. typhimurium were isolated from spleens of orally dosed mice up to day 30. Intravenous (i.v.) immunization with the gD-expressing construct did, however, induce detectable serum antibody responses. Some humoral IgA responses against gD in faecal samples were detected as early as 3 weeks post-oral immunization while those induced by the i.v. route were slightly lower. These data suggest that recombinant S. typhimurium HSV antigens are capable of inducing immunity against HSV, some aspects of which are protective against HSV challenge.

Administration, Oral↗
PubMed1997

Longitudinal study of plasma cortisol and 17-hydroxyprogesterone in very-low-birth-weight infants during the first 16 weeks of life.

There are few published data on plasma cortisol and 17-hydroxyprogesterone (17-OHP) in very-low-birth-weight (VLBW) infants beyond the 1st week of life. We therefore measured plasma cortisol and 17-OHP longitudinally in 26 infants (median birth weight 930 g, median gestational age 28 weeks) from 1 to 16 postnatal weeks to document normative values. We also examined the effect of clinical state on plasma cortisol and 17-OHP levels. Median plasma cortisol decreased with postnatal age from 1 to 8 weeks (110 vs. 60 nmol/l; p = 0.0007) and with postconceptional age from 25 to 36 weeks (104 vs. 47 nmol/l; p = 0.002). Median plasma 17-OHP decreased with postnatal age from 1 to 16 weeks (17.0 vs. 7.1 nmol/l; p < 0.0005) and also with postconceptional age from 25 to 42 weeks (21.1 vs. 7.1 nmol/l; p < 0.0005). Plasma cortisol was not influenced by the clinical state. Median plasma 17-OHP was significantly higher for 'unwell' versus 'well' infants at 5-8 weeks postnatal age (23.0 vs. 12.5 nmol/l; p = 0.012) but not at other postnatal age intervals. These data provide information on adrenocortical function in VLBW infants during the first 4 months of life.

17-alpha-Hydroxyprogesterone↗
PubMed1997

Cholelithiasis in early infancy.

This report describes three children, age range 7 weeks to 5 months, who presented with obstructive jaundice secondary to gallstones. Previous Escherichia coli septicaemia and frusemide therapy were predisposing risk factors in two of the patients. All three were successfully treated with cholecystectomy and exploration of the common bile duct.

Ampulla of Vater↗
PubMed1996

Short-stay comprehensive inpatient pulmonary rehabilitation for advanced chronic obstructive pulmonary disease.

OBJECTIVE: To evaluate the effectiveness of short-term, comprehensive inpatient pulmonary rehabilitation in severe chronic obstructive pulmonary disease (COPD). DESIGN: Retrospective analysis of several outcome measures. SETTING: Inpatient pulmonary rehabilitation unit. PARTICIPANTS: Thirty-eight consecutive adult patients with advanced COPD referred to our inpatient pulmonary rehabilitation program between January 1 and December 31, 1994. All but one were referred from acute care hospitals. The mean forced expiratory volume in 1 second (FEV1) was .69L; 79% required supplemental oxygen. MAIN OUTCOME MEASURES: (1) Discharge status; (2) timed walk, with measurements of distance and exertional dyspnea; and (3) functional status. RESULTS: All patients were able to be discharged home after a mean length of stay of 9.9 days. The 12-minute walk distance increased by 66%, from 416 +/- 282 feet to 690 +/- 337 feet (p < .001). Dyspnea during the walk testing also improved: the resting score decreased from 2.87 to .97, the 6-minute score from 7.84 to 3.05, and postwalk score from 8.53 to 3.51 (all p < .001). All patients showed improvement in the Pulmonary Function Status Scale (PFSS), with the functional activities subsection increasing by 39%, the dyspnea score by 65%, and psychosocial score by 35% (all p < .001). CONCLUSION: Short-term improvement in multiple areas can be accomplished with comprehensive pulmonary rehabilitation of short duration. This is particularly relevant to the current health care environment that dictates shorter in-hospital lengths of stay.

Activities of Daily Living↗
PubMed1996

Effects of interleukins, colony-stimulating factor and tumour necrosis factor on human hair follicle growth in vitro: a possible role for interleukin-1 and tumour necrosis factor-alpha in alopecia areata.

The immune system may be involved in the regulation of normal hair follicle growth as well as in the pathogenesis of some hair diseases. Immunomodulatory cytokines not only act as mediators of immunity and inflammation but also regulate cell proliferation and differentiation and, as such, may play an important part in regulating hair growth. We have investigated the effects of a number of interleukins (IL), colony stimulating factors and tumour necrosis factors (TNF) on hair follicle growth in vitro. Dose-response studies showed that IL-1 alpha, IL-1 beta and TNF-alpha were potent inhibitors of hair follicle growth. The histology of hair follicles maintained with inhibitory doses of IL-1 alpha, IL-1 beta and TNF-alpha showed similar changes in hair follicle morphology, resulting in the formation of dystrophic anagen hair follicles. These changes in histology were characterized by the condensation and distortion of the dermal papilla, marked vacuolation of the hair follicle matrix, abnormal keratinization of the follicle bulb and inner root sheath, disruption of follicular melanocytes and the presence of melanin granules within the dermal papilla. Moreover, these changes in hair follicle morphology are similar to those reported in alopecia areata and suggest that IL-1 alpha, IL-1 beta and TNF-alpha may play an important part in the pathophysiology of inflammatory hair disease.

Alopecia Areata↗
PubMed1996

The post-irradiation lower motor neuron syndrome neuronopathy or radiculopathy?

It is not known whether the post-irradiation lower motor neuron syndrome results from radiation damage to motor neuron cell bodies or from damage to the nerve roots of the cauda equina. We studied six cases who had presented with testicular neoplasms, subsequently undergoing irradiation that encompassed inter alia para-aortic nodes with co-irradiation of the distal spinal cord and cauda equina. A predominantly motor disorder affecting the legs ensued after variable and often prolonged latencies (3-25 years). However, all patients also developed mild sensory features either initially or on prolonged follow-up. Sural sensory nerve action potentials (SNAPs) were normal in five. Mild sphincter symptoms occurred in three of five surviving cases after a mean of 7.9 years. MRI showed gadolinium enhancement of the cauda equina in two of three patients. The first reported neuropathological study, uncomplicated by metastatic disease, of the conus and cauda equina was performed in one patient who died. This showed a radiation-induced vasculopathy of the proximal spinal roots, with preservation of motor neuronal cell bodies and spinal cord architecture. These clinical, radiological, neurophysiological and pathological findings all point to a predominantly, but not exclusively, motor radiculopathy affecting the irradiated portion of the cauda equina proximal to the dorsal root ganglia. Radiation exposure exceeded 40 Gy both in our series and in previous reports. The natural history of this disorder is one of relentless deterioration occasionally punctuated by 1-2-year periods of stability. Post-irradiation lumbosacral radiculopathy is a more accurate name for this condition.

Adult↗
PubMed1996

Either of the major H2A genes but not an evolutionarily conserved H2A.F/Z variant of Tetrahymena thermophila can function as the sole H2A gene in the yeast Saccharomyces cerevisiae.

H2A.F/Z histones are conserved variants that diverged from major H2A proteins early in evolution, suggesting they perform an important function distinct from major H2A proteins. Antisera specific for hv1, the H2A.F/Z variant of the ciliated protozoan Tetrahymena thermophila, cross-react with proteins from Saccharomyces cerevisiae. However, no H2A.F/Z variant has been reported in this budding yeast species. We sought to distinguish among three explanations for these observations: (i) that S. cerevisiae has an undiscovered H2A.F/Z variant, (ii) that the major S. cerevisiae H2A proteins are functionally equivalent to H2A.F/Z variants, or (iii) that the conserved epitope is found on a non-H2A molecule. Repeated attempts to clone an S. cerevisiae hv1 homolog only resulted in the cloning of the known H2A genes yHTA1 and yHTA2. To test for functional relatedness, we attempted to rescue strains lacking the yeast H2A genes with either the Tetrahymena major H2A genes (tHTA1 or tHTA2) or the gene (tHTA3) encoding hv1. Although they differ considerably in sequence from the yeast H2A genes, the major Tetrahymena H2A genes can provide the essential functions of H2A in yeast cells, the first such case of trans-species complementation of histone function. The Tetrahymena H2A genes confer a cold-sensitive phenotype. Although expressed at high levels and transported to the nucleus, hv1 cannot replace yeast H2A proteins. Proteins from S. cerevisiae strains lacking yeast H2A genes fail to cross-react with anti-hv1 antibodies. These studies make it likely that S. cerevisiae differs from most other eukaryotes in that it does not have an H2A.F/Z homolog. A hypothesis is presented relating the absence of H2A.F/Z in S. cerevisiae to its function in other organisms.

Amino Acid Sequence↗
PubMed1996

A one year prospective study of the effect of life events and medication in the aetiology of schizophrenic relapse.

BACKGROUND: We set out to determine whether and to what degree life events independent of illness increase the risk of relapse in schizophrenia following withdrawal from medication in the previous 6 months, either by triggering a relapse in the following 4 weeks or by acting cumulatively over time. METHOD: Seventy-one patients fulfilling DSM-III-R criteria for schizophrenia with chronic illness were followed for 48 weeks and assessed on the LEDS scale. Half were treated with regular neuroleptic medication and half had been recently withdrawn from medication. A subgroup was randomised double-blind to treatment or placebo. RESULTS: A proportional hazards regression model showed that life events made a significant cumulative contribution over time (P < 0.05) to the risks of relapse and that ceasing medication made an independent contribution. The risk of relapse increased in proportion to the number of life events but no interaction between medication status and events could be detected, i.e. life events were not more closely associated with relapse on medication than off medication. For those of the sample exposed to the mean rate of life events during the study period, it was estimated that 23% of the relapse risk could be attributed to life events, and for those with twice the mean rate of events, 41%. In contrast, patients who continued on regular medication had 80% less risk of relapse than those who had been withdrawn from medication either by choice or under double-blind controlled conditions. CONCLUSIONS: A contribution of life events to the risk of relapse in schizophrenia was confirmed by this study but the hypothesis that life events trigger relapse was not supported, nor was the hypothesis that life events are more relevant to relapse in patients on maintenance medication than in patients off medication.

Adult↗