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Biomedical subjects

J Harrison

Publications and source records attributed to J Harrison.

At least 109 records · Page 6Linked to original sources
PubMed1996

Administration of peripheral parenteral nutrition: a prospective study comparing rotation of venous access sites with ultrafine cannulas.

Peripheral veins have been used successfully for patients requiring short- to medium-term total parenteral nutrition. This study prospectively compares two methods of peripheral parenteral nutrition (PPN). Forty-six patients requiring parenteral nutrition (PN) were identified prospectively. Fifty courses of PPN were prescribed using a standardized PPN formula of 9.3 g nitrogen, 1400 kCal, 2500 ml (KABI II, Pharmacia). Patients were randomized to receive PPN via 23G, 15 cm flexane catheters (Nutriline) inserted into an antecubital vein which remained in-situ with a continuous infusion over 24 h, or to receive 12-h cyclical infusions through peripherally sited 18G catheters (Venflon) which were removed postinfusion and reinserted into the contralateral forearm on alternate days. Data collected included duration, complications and cost of materials for each prescribed course. A scoring system to determine patient anxiety and depression and a questionnaire regarding patients' perspectives were evaluated. Fifty courses were prescribed, 26 by rotation of veins (RV) and 24 by Nutriline (N). Mean duration of feeding was 7.9 and 8.6 days, respectively; cost of materials were comparable 6.48/day (RV) vs 5.17/day (N); 2 RV patients failed to complete their course (no access [P< 0.05], whilst 9 N patients failed to complete their course (4 severe phlebitis, 2 no venous access, 2 septicaemia, 1 dislodged). Five patients required CPN (RV, N 3) while 4 remaining patients were fed by an alternative PPN method. The overall incidence of anxiety was 20% and of depression 16%, with no significant difference between groups. The majority of patients (87%) found mobility restricted. Twelve-hourly infusions via alternate forearm veins were significantly more successful than continuous infusions via Nutriline, both in terms of completion of the prescribed course and less venous morbidity. This study confirms that rotation of forearm veins allows affordable and successful PN administration to the majority of patients, with low PN-related morbidity.

Journal Article↗
PubMed1996

Synaesthesia: prevalence and familiality.

Synaesthesia is a condition in which a mixing of the senses occurs; for example, sounds trigger the experience of colour. Previous reports suggest this may be familial, but no systematic studies exist. In addition, there are no reliable prevalence or sex-ratio figures for the condition, which is essential for establishing if the reported sex ratio (female bias) is reliable, and if this implicates a sex-linked genetic mechanism. Two independent population studies were conducted in the city of Cambridge, England (studies 1 and 2 here), as necessary background to the family genetic study of synaesthesia (study 3). Studies 1 and 2 arrived at an almost identical prevalence rate for synaesthesia: approximately 1 case in 2000. The sex ratio found was 6:1 (female:male). A third of cases also reported familial aggregation. In study 3 six families were examined, and first-degree relatives were tested for genuineness of the condition. All six families were indeed multiplex for synaesthesia. Alternative modes of inheritance are discussed.

Chromosome Aberrations↗
PubMed1996

Effects of vibration on the hand-arm system of miners in India.

Sixty-six Jackhammer drillers and 35 blasters from two mines were clinically screened for hand-arm vibration syndrome (HAVS). The screening consisted of questionnaire-based information, clinical examination including measurement of phalangeal circumferences of fingers (FCT) and motor nerve conduction (MCV) studies. In a warm environment, the prevalence of symptom complexes suggested the existence of peripheral neuropathy and musculoskeletal abnormalities rather than any peripheral circulatory disorders. Clinical examination revealed soft tissue wasting in the hands (26 cases), ulnar nerve impairment (23 cases), median nerve impairment (16 cases) and Dupuytren's contracture (4 cases). Mean motor nerve conduction velocities of 59 out of 66 drillers who volunteered for this assessment were not significantly different from those of the 35 blasters. The results of their correlation coefficients varied considerably for MCVs when age and years of vibration exposure underwent regression analysis. However, comparison of MCV and FCT of 30 drillers with 30 matched blasters revealed that the mean MCV of the right median nerve in the vibration exposed group was significantly decreased (p < 0.01) and for the mean FCT, the proximal phalanxes of the right index finger, left thumb and left ring fingers were thinner in the vibration exposed group (p < 0.05).

Adult↗
PubMed1996

Control of resting ventilation rate in grasshoppers

We examined the effect of extracellular acid-base status and tracheal gas levels on the ventilation rate of resting Romalea guttata and Schistocerca americana grasshoppers. We manipulated haemolymph pH and [HCO3-] within normal physiological ranges using injections of HCl, NaOH, NaHCO3 and NaCl into the haemocoel. In contrast to terrestrial vertebrates, there was no evidence that extracellular acidification increases ventilation rate in grasshoppers. Elevation of haemolymph bicarbonate levels (by NaHCO3 injection) increased ventilation rate, while depression of haemolymph bicarbonate levels (HCl injection) had no effect. Injection of NaHCO3 also increased tracheal PCO2, suggesting that the effect of the NaHCO3 injection might be mediated by a sensitivity of the ventilatory system to tracheal gases. We tested for effects of tracheal gases on ventilation rate by independently manipulating tracheal PCO2 and PO2 using tracheal perfusions. Ventilation rate was positively correlated with tracheal PCO2 and negatively correlated with tracheal PO2. Increasing tracheal PO2 above normal resting levels or decreasing tracheal PCO2 below normal levels decreased ventilation rate. We conclude that quiescent grasshoppers regulate tracheal PCO2 and PO2 by varying ventilation rate and that both PCO2 and PO2 in the trachea stimulate ventilation in normal, resting grasshoppers.

Journal Article↗
PubMed1996

Haemolymph acid-base status, tracheal gas levels and the control of post-exercise ventilation rate in grasshoppers

In grasshoppers, ventilation rate increases after jumping, in association with decreases in haemolymph pH and tracheal PO2 and increases in haemolymph and tracheal PCO2. Are these changes in haemolymph acid-base status or tracheal gas composition causally responsible for the increases in post-locomotion ventilation rate? To answer this question, we manipulated haemolymph acid-base status with injections into the haemocoel and independently manipulated tracheal PO2 and PCO2 with tracheal perfusions. Using a new technique, we continuously monitored ventilation rate and ventilatory pressures on virtually unrestrained insects. Changes in haemolymph acid-base status or tracheal PCO2 did not affect post-exercise ventilation rate, clearly demonstrating that the ventilatory stimulus associated with locomotion is not dependent on negative feedback from these variables. Post-exercise ventilation rate varied with tracheal PO2, with the lowest ventilation rates observed at the lowest tracheal PO2 values, a result opposite to that expected if negative feedback from internal PO2 levels were to drive the increase in ventilation rate. Particularly after activity, there was considerable heterogeneity in unperfused animals between tracheal and haemolymph PCO2, and between tracheal PCO2 in the thorax and leg, consistent with unidirectional airflow and a considerable role for diffusion gradients in the gas exchange of grasshoppers.

Journal Article↗
PubMed1996

Methodological issues in evaluating HIV prevention community planning.

To be effective, HIV prevention programs should be planned in partnership with affected communities and should be built on a solid scientific foundation. In 1994, the Centers for Disease Control and Prevention (CDC) and its prevention partners implemented HIV prevention community planning to achieve primarily these two objectives. In order to manage the community planning process effectively, extensive evaluation activities were employed at both the grantee and national level. This paper describes the first year evaluation goals and methods in detail. Throughout, reasons for collecting specific types of information and for using particular methodologies are highlighted.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Effect of bethanechol or erythromycin on gastric emptying in horses.

OBJECTIVE: To investigate the prokinetic effect of bethanechol and erythromycin in the upper gastrointestinal tract of healthy horses by measuring the gastric emptying (GE) rate of a radioactive meal. ANIMALS: 4 healthy adult horses. PROCEDURE: After food was withheld for 12 hours, horses were given 370 MBq of 99mTc-labeled sulfur colloid incorporated into egg albumen and 37 MBq of 111In-labeled diethyltriaminepentaacetic acid in 120 ml of water via nasogastric intubation. Intravenously administered treatments were 0.9% NaCl solution, erythromycin (0.1 or 1.0 mg/kg of body weight), or bethanechol (0.25 mg/kg). All drugs were given in 10 ml of 0.9% NaCl solution. Dual-phase scintigraphic images were obtained by use of a gamma camera. The best-fit function was determined for each study, and the resultant curves were then analyzed by use of least squares nonlinear regression. Two variables, time to 50% emptying of the stomach (T-50) and slope of the emptying curve, were derived from the calculated power exponential equation. CONCLUSIONS: Treatment had a significant (P < 0.05) overall effect on T-50 of solid-phase GE. The T-50 of bethanechol (30.09 +/- 10.01 minutes), erythromycin at 0.1 mg/kg (59.08 +/- 10.01 minutes), and erythromycin at 1 mg/kg (60.50 +/- 10.01 minutes) were significantly shorter than T-50 after saline administration (89.97 +/- 10.01 minutes). There was a trend (P = 0.09) for the slope of solid-phase GE of bethanechol and erythromycin (0.1 mg/ kg; P = 0.37) to be steeper than that of saline solution. For liquid-phase GE, the T-50 and the slope of bethanechol differed significantly (P < or = 0.05) from those for saline solution. CLINICAL RELEVANCE: Bethanechol and erythromycin significantly increased solid-phase GE in healthy horses and may have value for use as prokinetic agents in certain gastrointestinal tract diseases.

Animals↗
PubMed1995

Metabolism and blood-brain clearance of L-3,4-dihydroxy-[3H]phenylalanine ([3H]DOPA) and 6-[18F]fluoro-L-DOPA in the rat.

6-[18F]fluoro-L-DOPA (FDOPA) has been used as a tracer for the cerebral activity of L-3,4-dihydroxyphenylalanine (DOPA)-decarboxylase in studies of positron emission tomography (PET). However, the substitution of fluorine on the aromatic ring may alter the disposition and metabolism of FDOPA from that of endogenous DOPA. In the present study, the kinetics of the peripheral metabolism and the facilitated unidirectional blood-brain clearance of [3H]DOPA and FDOPA were compared in Wistar rats pretreated with carbidopa. In arterial plasma, FDOPA was O-methylated with an apparent rate constant (0.031 min-1) 3-fold that of [3H]DOPA in the same rats. The O-methylated metabolite of FDOPA (OMe-FDOPA) was eliminated from plasma at a rate constant (0.018 min-1) 3-fold that of OMe-[3H]DOPA. The mean unidirectional blood-brain clearance of FDOPA (4.5 mL.hg-1.min-1) in six brain regions was 60% higher than that of [3H]DOPA.

Animals↗
PubMed1995

The internal control of action and Parkinson's disease: a kinematic analysis of visually-guided and memory-guided prehension movements.

This paper reports two experiments which examined the effects of Parkinson's disease (PD) upon the sensorimotor mechanisms used to control prehension movements. Transport and grasp kinematics for visually-guided and memory-guided prehension movements were examined in healthy control subjects and compared against those of patients with idiopathic PD. Two research questions were addressed: (1) Are patients with PD particularly susceptible to distraction by non-relevant objects? (2) Are patients with PD especially reliant on external feedback when executing goal-directed actions? The results indicated that the patient group were no more susceptible to distraction by non-relevant objects than the control group. In contrast, the patients with PD were shown to be significantly impaired when executing memory-guided reaches. Furthermore, the deficits exhibited by the PD group on memory-guided reaches were confined solely to those markers associated with the transport component of the prehension movement. That is, while both controls and patients with PD widened their grip aperture on memory-guided trials, the magnitude of this adjustment was comparable across the two groups. The implications of these findings for theories of visuomotor processing in sufferers of PD and the control of prehension movements more generally are discussed.

Aged↗
PubMed1995

Serial reaction time learning and Parkinson's disease: evidence for a procedural learning deficit.

This paper presents evidence in support of a serial reaction time (SRT) deficit associated with Parkinson's disease, and related to the acquisition or execution of serial-order information. Eleven patients with idiopathic Parkinson's disease, and 10 age-matched but otherwise healthy control subjects, were compared on a variant of the SRT task introduced by Nissen and Bullemer (Cognit. Psychol. 19, 1-32, 1987). The results of this study clearly demonstrate that PD patients produce a quite different pattern of RT performance to that of control subjects. Such a pattern of results may reflect either: (1) a deficit in the patients' ability to learn the temporal order information provided by a repeating sequence of target locations in the SRT task; or (2) a deficit in the patients' ability to express temporal order information provided by the repeating sequence of target locations in the SRT task.

Aged↗
PubMed1995

Synaesthesia: reconciling the subjective with the objective.

Coloured hearing synaesthesia (from the Greek syn (union) and aisthesis (sensation)), has been known to the scientific community for over 300 years and yet has gone relatively uninvestigated. This review charts recent progress in the investigation of synaesthesia and discusses the consequences of this research for our understanding of the condition.

Auditory Perception↗
PubMed1995

Confiding in crisis: gender differences in pattern of confiding among cancer patients.

Social support has been identified as a key predictor of psychological morbidity following adverse life-events. However, the majority of the research has focused exclusively on women, despite evidence of significant gender difference in the utilisation and role of social support. To examine gender differences in patterns of confiding crisis, 520 subjects were interviewed within 8 weeks of a cancer diagnosis. Men were as likely as women to have confided their main concern in others (61% mainly or fully confided vs 67% of women, P = 0.308) but were much more likely to have used only one confidante (45% vs 25% of women, P < 0.001) while women made use of a wider circle of family, friends and partner and used more confidantes overall. The results confirm marked gender differences in the utilisation of social support at times of crisis and call into question the extent to which support research using exclusively female samples can be generalized.

Adaptation, Psychological↗
PubMed1995

Ambient, biological, and biological effect monitoring of exposure to polycyclic aromatic hydrocarbons (PAHs).

A novel strategy was utilised to assess the risk to health from exposure to polycyclic aromatic hydrocarbons (PAHs). Ambient monitoring was carried out by personal sampling. Urinary thioethers (UTh) and urinary 1-hydroxypyrene (1-HP) were utilised for biological monitoring. Urinary d-glucaric acid (UDGA) and sister chromatid exchange (SCE) in peripheral blood lymphocytes were used as biological effect markers. The population was categorised into exposed and control groups according to the external dose of PAHs. The excretion of 1-HP in the controls over the 3-day period showed a relatively stable baseline, while the exposed showed a significant increase over the same period of time. SCE frequency in the exposed population was significantly different from controls.

Adult↗
PubMed1995

The impact of cancer on key relatives: a comparison of relative and patient concerns.

This study examines the impact of diagnosis on key relatives of 108 newly diagnosed cancer patients. Cancers of the breast, colon, female reproductive tract and testicle were included. Relatives completed a self-report checklist of concerns and the General Health Questionnaire (GHQ) (28 items). Patients were administered a corresponding concerns checklist as part of a semi-structured interview. More relatives than patients expressed each of the nine common concerns; the discrepancy was greatest for concern about the patient's emotional reaction, reported by 95% of relatives and only 18% of patients. The total relatives' concern score (median 16.0) was significantly greater than the patients' score (median 4.0) (P < 0.0001). Cancer type, age of patient and nature of relationship to patient had little impact on the frequency of relatives' concerns. 52 (48%) relatives scored above the usual cut-off on the GHQ, suggesting significant psychological morbidity. Relatives of newly diagnosed cancer patients report high levels of concerns and psychological distress, and deserve greater attention than they currently receive.

Adolescent↗
PubMed1995

A multidisciplinary audit of manual hyperinflation technique (sigh breath) in a neurosurgical intensive care unit.

Manual hyperinflation of the lungs (sigh breath) is a technique which is used to deliver a large volume of gas to the lungs. The purpose of this technique is to either maintain or improve the respiratory status of the patient. However, the volume of gas delivered is rarely measured, and therefore there is little evidence that hyperinflation occurs. Through the process of audit staff were able to examine the technique critically and improve it. With the addition of measurement tools a defined standard was developed against which performance was measured. To explore the effects of a particular technique it is essential that the delivery of that technique is standardised. This audit has enabled staff to achieve a standard technique and create a position from which research into its effects can now take place.

Clinical Protocols↗