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Biomedical subjects

R Harrison

Publications and source records attributed to R Harrison.

At least 55 records · Page 3Linked to original sources
PubMed1991

The Longwood Medical Area Network.

The Longwood Medical Area Network (LMAnet) is a high speed fiber optic network that connects several patient care, research, and educational organizations in Boston's Longwood Medical Area. This paper describes the architecture of the network, current and potential future uses of the network, network costs and administration, and management issues associated with the use of LMAnet.

Boston↗
PubMed1991

Pharmacokinetics of dopamine in infants and children.

OBJECTIVE: We studied the pharmacokinetics of dopamine in hemodynamically stable children. DESIGN: Prospective clinical trial. SETTING: Pediatric ICU. PATIENTS: Children (age 3 months to 13 yrs) recovering from cardiac surgery or shock. INTERVENTION: Plasma dopamine concentrations were measured at the steady state or at termination of infusion using high-performance liquid chromatography. RESULTS: The half-lives of distribution and elimination were 1.8 +/- 1.1 and 26 +/- 14 (SD) mins, respectively. The apparent volume of distribution was 2952 +/- 2332 mL/kg. The clearance rate was 454 +/- 900 mL/kg.min. Dopamine clearance was linearly related to dose only in patients who were also receiving dobutamine (r2 = .76, p less than .05). Hepatic and renal dysfunction did not affect the pharmacokinetics of dopamine. CONCLUSIONS: A relationship between dopamine and dobutamine that affects the disposition of these two drugs may exist. The pharmacokinetics of dopamine are variable even in hemodynamically stable children. Hepatic or renal function does not adversely affect the pharmacokinetics of dopamine.

Child↗
PubMed1991

Localisation of xanthine oxidase to synovial endothelium.

The presence of the xanthine oxidase enzyme system has been demonstrated in the rheumatoid synovium. This supplies a reactive oxygen species generating system to synovium that is subjected to hypoxic-reperfusion cycles (cf inflamed rheumatoid synovium). An antibody to bovine milk xanthine oxidase has been used to localise the enzyme by immunohistochemistry to synovial endothelium. This implicates the endothelial cell as playing a major part in exacerbations of synovitis, induced by radicals.

Antigens↗
PubMed1991

Neuropsychological impairment among former microelectronics workers.

Although chemicals posing potential neurotoxic hazards are commonly used in the microelectronics industry, there has been no systematic study of possible chronic nervous system effects in microelectronics workers. The objective of the present study was to assess neuropsychological functions of a group of former microelectronics plant assembly workers and a group of referents, using a matched pair design. During employment, the former microelectronics workers had been exposed to multiple organic solvents, including trichloroethylene, xylene, chlorofluorocarbons and trichloroethane. Referents were recruited from the same geographic region. From a pool of 180 former workers and 157 referents, 67 pairs were matched on the basis of age, sex, ethnicity, educational level, sex and number of children. Comparison of results on the subtests of the California Neuropsychological Screening Battery-Revised (CNS-R) revealed significantly lower performance by the former microelectronics workers on tests of attention/concentration, verbal ability, memory functions, visuospatial functions, visuomotor speed, cognitive flexibility, psychomotor speed, and reaction time (t-test for pairs or Wilcoxon Signed Rank p less than 0.05). No significant differences were observed for performance on tests assessing mental status, visual recall, tactile function and learning. This overall pattern of impairment is consistent with organic solvent-related chronic toxic encephalopathy, and possible early stages of dementia. These findings underline the need for more studies among workers currently or previously employed in microelectronics industries.

Adult↗
PubMed1990

Neurotrophic activities of normal and motor neurone disease patient skeletal muscle extract on cultured rat spinal neurones.

Cultured foetal rat spinal neurones, grown in serum-free medium from day 3, respond to neuronotrophic factors present in adult human skeletal muscle extracts. Levels of total protein, neurofilament protein and choline acetyltransferase (ChAT) activity are all increased approx. 2 to 3-fold at 200 micrograms extract/ml medium. Culture survival is also extended from an average of 21 days to more than 30 days. Extracts prepared from skeletal muscle biopsies of motor neurone disease (MND) patients do not differ significantly from non-MND patient muscle extracts in their ability to boost the parameter levels or survival of the cultures. The results show no evidence that neuronotrophic factors are lacking in the skeletal muscle of MND patients.

Animals↗
PubMed1990

Pion therapy at TRIUMF. Treatment results for astrocytoma grades 3 and 4: a pilot study.

At TRIUMF, (located on the University of B.C. Campus), 53 patients with supratentorial astrocytoma grades 3 and 4 were treated with pions between 1982 and 1985. A 3-dimensional spot-scanning treatment technique has proven to be practical. The accuracy of the beam alignment system used for treatment was reproducible daily within 2 mm. Low pion flux has hindered optimal beam shaping but this will soon be remedied as flux improves. The overall median survival observed (53 patients) is 262 days from date of first radiation treatment. Younger (less than 49 years) patients have significantly better survival than older (greater than 50 years) patients (p = 0.001). From a base line dose of 40 Gy photons whole brain and 17.5 Gy pion boost, doses were escalated to 33 Gy pions localised to the primary tumour and the median survival improved from 198 to 436 days. Survival curves for patients treated with localised pion techniques to doses above 30 Gy are significantly better than for those treated with schedules of pions mixed with photons (p = 0.04). It appears that optimal pion dose for brain tumours is 33 Gy minimum with a possible maximum of 36 Gy and doses delivered in 15 fractions in 3 weeks. Requirements for future trials are discussed.

Adult↗
PubMed1990

Inferior turbinectomy: comparison of four techniques.

As yet, there is not totally satisfactory means for treating hypertrophied turbinates and the proper management of turbinate dysfunction remains in question. In the present series, four of the widely practiced surgical procedures for the reduction of the size of the inferior turbinates were evaluated and compared. In all cases turbinectomy was performed as an isolated procedure. Eighty patients with chronic non-allergic rhinitis and hypertrophied inferior turbinates were selected, randomly divided into four groups, and followed up post-operatively for one year. Study of the results indicated that the beneficial effect of the operation is mainly mechanical by reduction of the resistance to nasal airflow. The post-operative improvement in smell acuity correlated positively with the increased patency of the nasal airway. None of the procedures had a deleterious effect on olfactory acuity. In contrast, the operation failed to enhance the mucociliary clearance rate or significantly decrease nasal drainage. Partial inferior turbinectomy and laser turbinectomy improved nasal breathing in 77 per cent of patients, and enhanced olfactory acuity in 78 per cent of patients who had pre-operative hyposmia. The results of turbinoplasty and cryoturbinectomy were less favourable. The surgical technique, advantages, and drawbacks of each of these procedures are discussed.

Adult↗
PubMed1990

Dementia, depression and physical disability in a London borough: a survey of elderly people in and out of residential care and implications for future developments.

We studied 1303 of the 1471 elderly people resident in Local Authority homes, NHS long-stay wards (medical and psychiatric), private and voluntary homes and Local Authority sheltered housing or in receipt of augmented domiciliary services in the London Borough of Waltham Forest. Depression and dementia were assessed using the Brief Assessment Schedule and physical functioning by a modified Barthel index. Residents with high levels of dependency were spread throughout the different forms of residential accommodation. There was little disability outside residential care. There was a high prevalence of depression in the study population. These findings are relevant to future plans for services for elderly people.

Aged↗
PubMed1990

Antibodies to xanthine oxidase: elevated levels in patients with acute myocardial infarction.

Circulating antibodies to whole dried cows' milk, previously reported to be elevated in patients with myocardial infarction, have been shown to be directed mainly to the bovine milk fat globule membrane. Human antibodies against the bovine milk fat globule membrane themselves interact primarily with the enzyme, xanthine oxidase. Comparison of anti-(xanthine oxidase) antibody levels in 107 patients, who had suffered a myocardial infarction, with those in 86 control subjects showed significantly higher IgM levels in the patients with myocardial infarction. No corresponding differences were found for IgG or IgA anti-(xanthine oxidase) antibodies. Total levels of IgM class immunoglobulins did not differ between patients and controls. Serial assays following myocardial infarction showed no evidence that raised levels of IgM anti-(xanthine oxidase) antibodies result from the infarction itself.

Antibodies↗
PubMed1990

Experimental infection of timed-pregnant rhesus monkeys with simian immunodeficiency virus (SIV) during early, middle, and late gestation.

Ten rhesus monkeys were inoculated with SIV/DeltaB670 during various stages of gestation to determine factors predictive of transplacental infection. Two abortions associated with rapid disease occurred shortly after infection; uninfected infants were caesarean delivered from eight other females. SIV-specific RNA accompanied by deciduitis was identified in the maternal portion of two placentas suggesting that opportunistic infections may promote entry of SIV into placental tissue. The lack of evidence for SIV infection of caesarean delivered infants suggests that fetal infection may often occur during parturition.

Abortion, Spontaneous↗