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Biomedical subjects

J Bowen

Publications and source records attributed to J Bowen.

At least 19 recordsLinked to original sources
PubMed1995

Oxytocin changes in males over the reproductive cycle in the monogamous, biparental California mouse, Peromyscus californicus.

Levels of plasma oxytocin in male Peromyscus californicus were assessed across the reproductive cycle to provide a foundation for subsequent studies of the hormonal basis of paternal behavior and pair bonds. In Experiment 1, plasma oxytocin levels were significantly higher in expectant fathers than in virgin males or fathers. Plasma oxytocin increased in expectant fathers 1 day postcopulation and remained elevated for the first 15 days of gestation. Plasma oxytocin declined by Day 20 of gestation and oxytocin levels remained low in fathers throughout the lactational period. Oxytocin levels among expectant fathers did not differ between parental and nonparental males or between infanticidal and noninfanticidal males, suggesting that plasma oxytocin may not be involved in the prepartum onset of paternal behavior or the inhibition of infanticide. In Experiment 2, plasma oxytocin levels also did not differ between males that were parental or non-parental prepartum or postpartum. However, males separated from their mate and pups on the day of birth had elevated oxytocin levels on Day 3 postpartum compared to males that remained with their family, suggesting that disruption of the pair bond and/or absence of the young affects plasma oxytocin levels in males. This possibility remains to be determined.

Animals↗
PubMed1995

Acetylation of lysine 40 in alpha-tubulin is not essential in Tetrahymena thermophila.

In Tetrahymena, at least 17 distinct microtubule structures are assembled from a single primary sequence type of alpha- and beta-tubulin heterodimer, precluding distinctions among microtubular systems based on tubulin primary sequence isotypes. Tetrahymena tubulins also are modified by several types of posttranslational reactions including acetylation of alpha-tubulin at lysine 40, a modification found in most eukaryotes. In Tetrahymena, axonemal alpha-tubulin and numerous other microtubules are acetylated. We completely replaced the single type of alpha-tubulin gene in the macronucleus with a version encoding arginine instead of lysine 40 and therefore cannot be acetylated at this position. No acetylated tubulin was detectable in these transformants using a monoclonal antibody specific for acetylated lysine 40. Surprisingly, mutants lacking detectable acetylated tubulin are indistinguishable from wild-type cells. Thus, acetylation of alpha-tubulin at lysine 40 is non-essential in Tetrahymena. In addition, isoelectric focusing gel analysis of axonemal tubulin from cells unable to acetylate alpha-tubulin leads us to conclude that: (a) most or all ciliary alpha-tubulin is acetylated, (b) other lysines cannot be acetylated to compensate for loss of acetylation at lysine 40, and (c) acetylated alpha-tubulin molecules in wild-type cells contain one or more additional charge-altering modifications.

Acetylation↗
PubMed1995

The flank approach to the porcine upper urinary tract: safe and reliable.

An extra-peritoneal flank approach was used to gain access to the left pelviureteric junction of 8 young pigs. The operative procedure was simple and took 15 min to complete. There were no serious complications, analgesia requirements were negligible and all animals re-established on feeds within 12 h post-operatively. The operative procedure is described; due to the above considerations the flank approach to the porcine kidney can be recommended.

Animals↗
PubMed1994

The Mini-Mental State Examination score and the clinical diagnosis of dementia.

To set a working cutoff score for the referral to diagnostic examination, we evaluated 150 consecutive patients with complaints potentially related to dementia, using the Mini-Mental State Examination (MMSE). All patients were later given a complete, standardized work-up and diagnosis as part of our Alzheimer's Disease Patient Registry protocol. Dementia diagnosis was made, consistent with accepted criteria, by consensus of the physicians and psychologist. Diagnosis was reaffirmed after 1-year follow-up exam; 133 of the 150 original patients completed follow-up (80 dementia, 53 no dementia). We evaluated the initial MMSE score compared with the follow-up diagnosis. Sensitivity, specificity, and predictive values were calculated for MMSE scores ranging from 22 through 29. The conventional cutoff score of < 24 shows a sensitivity of 0.63 and a specificity of 0.96; sensitivity increased at higher cutoff scores. Multivariate analysis showed that educational level added significant prediction only at scores of > or = 27. We conclude that an MMSE score of 26 or 27 should be used as a cutoff score in symptomatic populations with similar educational and socioeconomic backgrounds when the goal is to miss few true cases. Population surveys where the expected prevalence is low may require a different cutoff score to indicate the need for further diagnostic evaluation.

Aged↗
PubMed1994

Chronic hydronephrosis: renographic drainage patterns and renal morphology in an animal model.

OBJECTIVE: To develop an animal model of chronic progressive hydronephrosis; to establish patterns of diuretic renography during development of the condition; and to relate renographic abnormality to morphological change in the renal parenchyma. MATERIALS AND METHODS: The cellophane sclerosis technique was used to produce a hydronephrosis in the left kidney of six rabbits. Post-operatively MAG3 diuretic renography was performed at weekly intervals. When a steady renographic trend was noted the rabbits were killed and the kidneys examined histologically. RESULTS: Four rabbits had persistent type II renographic curves on the left for 12 weeks. The measured split renal function fell steadily to < 20% in this time. Morphologically there was hydronephrosis with marked structural changes in the parenchyma seen on histological examination. Two rabbits had stable type IIIa renographic drainage patterns on the left with preserved renal function. Morphologically there was hydronephrosis but histologically the kidneys were normal. There were no renographic or structural changes in a control rabbit after a sham laparotomy. CONCLUSIONS: The cellophane sclerosis technique can be used to create a reproducible chronic progressive hydronephrosis. In this animal model hydronephrosis and a persistent type II curve are associated with renographic evidence of deteriorating renal function and disruption of renal architecture histologically. Hydronephrosis and a type IIIa curve are associated with preservation of normal renal function and histological structure.

Animals↗
PubMed1994

Causes of death associated with Alzheimer disease: variation by level of cognitive impairment before death.

OBJECTIVE: To describe causes of death for patients with Alzheimer disease (AD) and other dementing illnesses enrolled in a population-based Alzheimer disease patient registry (ADPR) and to describe the variation in causes by the level of cognitive impairment before death in probable AD cases. SETTING: The ADPR enrolls and diagnoses newly recognized potential dementia cases occurring in a large, stable health maintenance organization. To date, 654 cases have been enrolled and followed annually to monitor cognitive decline and verify initial diagnosis. DESIGN: Longitudinal descriptive study. PATIENTS: ADPR enrollees who have died. MEASUREMENTS: Death certificates were obtained for all who died (total n = 104, probable AD = 55); reported causes of death were reviewed by a physician to determine the underlying cause. AD patients were categorized according to their Mini-Mental State Exam score (cognitive impairment) within 12 months of death as (a) mildly (21+), (b) moderately (15-20), or (c) severely (0-14) impaired, and underlying cause and all reported causes of death for each group were tabulated. MAIN RESULTS: Among probable AD patients, pneumonia and AD were most often recorded on death certificates when cognitive impairment within the year prior to death had reached the severe level; heart disease, stroke, and other common causes of death predominated in AD patients who were less cognitively impaired. CONCLUSIONS: When AD cases were followed from first diagnosis to death, the causes of death varied by level of cognitive impairment. Illnesses potentially amenable to treatment caused death at all levels of disease, but more so early in the course of AD. Cognitive impairment may make patients less able to recognize and report symptoms of medical problems, thereby complicating efforts to intervene.

Aged↗
PubMed1994

Effect of a stroke protocol on hospital costs of stroke patients.

OBJECTIVE: To determine the impact of a protocol on hospitalization costs for patients admitted with stroke. DESIGN AND SETTING: Nonrandomized control trial in an urban community hospital with 376 beds. PATIENTS: All patients admitted with a diagnosis-related group code of 014 (cerebrovascular disease) were included (N = 390). Patients with subdural hematoma (N = 2) or subarachnoid hemorrhage (N = 2) were excluded. INTERVENTION: A protocol for treatment of acute stroke was developed that included a critical path for nursing care, an algorithm for emergency department care, and suggested admission orders for physicians. MAIN OUTCOME MEASURES: The hospital information system computer database was searched for hospitalization charges, length of stay, tests performed, and treatments provided. RESULTS: Patients treated with the protocol had lower charges compared with historical (p = 0.026) and concurrent (p = 0.02) control groups. Lower charges were accounted for by a decreased length of stay in the protocol group compared with historical (p = 0.001) and concurrent (p = 0.13) controls. Tests and treatments provided were similar except that carotid Doppler studies and deep venous thrombosis prophylaxis were more frequently done in those treated with the protocol (p = 0.001 for carotid Doppler and p = 0.026 for deep venous thrombosis prophylaxis). There were no differences in outcome measures such as death or discharge disposition. Medical complications were similar in all groups. CONCLUSIONS: There were significant savings in hospitalization cost for patients with acute stroke after introduction of a treatment protocol. These savings were almost entirely related to decreased length of stay. The protocol led to modest differences in tests ordered and treatments provided.

Acute Disease↗
PubMed1994

[Failure factors in endometrial resection. 196 cases].

OBJECTIVE: Study of factors affecting risk of failure after hysteroscopic endometrial resection. METHODOLOGY: A retrospective study of 196 patients treated by hysteroscopic endometrial resection for abnormal uterine bleeding from January 1989 to December 1990. A survey was conducted in February 1993 to study the results of these interventions with a particular attention paid to the failure cases. RESULTS: The survey revealed a satisfaction rate of 82%. Persistence of abnormal bleeding after resection was the most common problem reported, although in 32% of these cases the bleeding began after a period of at least 2 years in remission. A more complete clinical and pathological study was performed in 22 cases of hysterectomy for failure after resection. Enlarged uterine size and presence of adenomyosis increase significantly the failure rates. CONCLUSION: After 2 or 4 years of follow-up, the results are satisfactory but the existence of late recurrences showed that it will be necessary to have long term reviews. Two major risk factors are enlarged uterine size and the presence of adenomyosis.

Adult↗
PubMed1992

The Marfan syndrome: cardiovascular physical findings and diagnostic correlates.

Correlations among cardiac symptoms and auscultatory and phonoechocardiographic findings in Marfan syndrome have not been completely defined. A total of 24 patients with Marfan syndrome (16 men and 8 women; mean age 28.2 +/- 8.6 years) were studied. Mitral valve prolapse was noted in 22, of whom 19 had either nonejection systolic click or mitral regurgitation murmur. Mitral regurgitation was noted in 12 patients by Doppler imaging. Aortic root dilatation was noted in 20 patients and aortic regurgitation in six, five of whom had aortic regurgitation murmur (5 of 20 patients had undergone surgery). Proximal aortic dissection was noted in two. Dyspnea (n = 12) was associated with progressive mitral or aortic regurgitation in four, but in the others dyspnea could not be explained by valvular or ventricular abnormalities. Chest pain was related to pneumothorax in five and aortic dissection in two but was not associated with either in 15 patients. Palpitations (n = 12) and lightheadedness (n = 6) were not associated with specific arrhythmias. In conclusion, mitral valve prolapse and aortic root dilatation were the most common cardiovascular abnormalities in Marfan syndrome. Mitral valve prolapse was frequently associated with typical auscultatory findings and symptoms including dyspnea, chest pain, palpitations, and lightheadedness, whereas aortic root dilatation could be clinically silent unless complicated by aortic regurgitation or aortic dissection.

Adult↗
PubMed1992

The effects of ispaghula on rat caecal fermentation and stool output.

The colonic fermentation of ispaghula, a mucilage from Plantago ovata composed mainly of arabinoxylans, and its effects on stool output and caecal metabolism were investigated. Four groups of eight rats were fed on a basal diet (45 g non-starch polysaccharides/kg) for 28 d. The diet was then supplemented with ispaghula (g/kg; 0, 5, 15 or 50) for 28 d. Ispaghula increased stool dry weight and apparent wet weight but faecal water-holding capacity (amount of water held per g dry faecal material at 0.2 mPa) was unchanged. The extent of faecal drying in the metabolism cages was measured for rats fed on the basal diet and 50 g ispaghula/kg diet. At the faecal output levels encountered, only an 8% loss of wet weight would be predicted over 24 h and this was independent of diet. Faecal short-chain fatty acid (SCFA) concentration did not change but SCFA output increased. The molar proportion of SCFA as propionic acid increased and faecal pH was reduced. Values from pooled faecal samples suggested that approximately 50% of the ingested ispaghula was excreted by the 50 g ispaghula/kg diet group. Diaminopimelic acid (a constituent of bacterial cells) concentrations fell but output was unchanged indicating no change in bacterial mass. Similar changes were seen in the caecal contents but caecal pH and SCFA were unaffected. Ispaghula increased both caecal and colonic tissue wet weight and colonic length. Our results suggest that ispaghula is partly fermented in the rat caecum and colon, and loses its water-holding capacity. However, it is still an effective stool bulker and acts mainly by increasing faecal water by some unknown mechanism.

Animals↗
PubMed1992

Stroke after pituitary irradiation.

BACKGROUND AND PURPOSE: Cranial irradiation may lead to accelerated atherosclerosis over several years. Stroke has been described after cranial irradiation administered for a number of conditions. However, pituitary irradiation has only rarely been associated with stroke. CASE DESCRIPTIONS: Two patients, 39 and 46 years of age, suffered strokes 13 and 20 years, respectively, after irradiation for pituitary tumors. Strokes were in the territories of small perforating arteries, but large vessels such as the carotid siphon and anterior cerebral arteries were also abnormal. Other risk factors for stroke were absent. CONCLUSIONS: It is suggested that pituitary irradiation increases the risk of subsequent stroke due to the known effects of ionizing radiation on vascular walls.

Adenoma, Chromophobe↗
PubMed1992

Schizophrenics and social judgement. Why do schizophrenics get it wrong?

Videotaped social interactions were shown to a population of schizophrenics and controls who were asked to comment on the emotional state of the principal protagonist. Their free responses were subjected to a content analysis to examine which of three possible explanations of known schizophrenic inaccuracies on this task were responsible: formal thought disorder, selective avoidance of psychological factors, or perceptual/attentional deficits. Neither selective avoidance nor marked thought disorder were found to explain these errors. The schizophrenics as a group rated much the same, irrespective of clinical profile. Their judgements of personality were less clear-cut than the controls.

Adult↗
PubMed1992

Combined modality preoperative therapy for unresectable rectal cancer.

Locally advanced rectal cancer has been a surgical challenge because of fixation of the primary tumor to the boney pelvis or to other pelvic soft tissues. During a 12-month period seven patients with locally advanced adenocarcinoma of the rectum were treated preoperatively with simultaneous pelvic irradiation (4500-5040 cGy) and infusion chemotherapy (5-fluorouracil 1000 mg per m2 per day over 96 hours and mitomycin 10 mg per m2. Tolerance was reasonable and all patients underwent successful resection of the primary lesion. Two patients had a complete response to preoperative combined modality therapy with no cancer found in the surgical specimen. With a short follow-up period, all patients have experienced satisfactory healing and none have suffered local or distant recurrence. The results of this limited series are encouraging for future clinical trials.

Adenocarcinoma↗
PubMed1991

Stimulant medication and attention deficit-hyperactivity disorder. The child's perspective.

Fifty-eight children receiving stimulant medication for attention deficit-hyperactivity disorder at referral clinics for learning disabilities at two teaching hospitals in Massachusetts were invited to participate in a study of their knowledge and attitudes. The 45 respondents and parents completed separate questionnaires concerning how they felt about receiving stimulant medication. Eighty-nine percent of the children felt that the medication was helpful and 78% liked or were indifferent to it despite a high rate (85%) of reported side effects. The five children (11%) who responded that they would stop taking stimulant medication if they could were more likely to perceive the medication as unhelpful and were receiving standard methylphenidate hydrochloride rather than a long-acting preparation. We conclude that children's perspectives on medication should be elicited directly and sustained-release medication may be more acceptable to children with attention deficit-hyperactivity disorder.

Adolescent↗