Search PubMed⌕ Search

Biomedical subjects

J Dick

Publications and source records attributed to J Dick.

At least 37 records · Page 2Linked to original sources
PubMed1998

A graphical tool for ad hoc query generation.

Medical data are characterized by complex taxonomies and evolving terminology. Questions that clinicians, medical administrators, and researchers may wish to answer using medical databases are not easily formulated as SQL queries. In this paper we describe a graphical tool that facilitates formulation of ad hoc questions as SQL queries. This tool manages multiple attribute hierarchies and creates SQL query strings by navigating through the hierarchies. This interactive tool has been optimized using indexing to improve the overall speed of the query building and the data retrieval process. Indexed queries performed 5 to 100 times faster than query strings. However, query string generation time depends on the size of the taxonomies describing the hierarchies, while the index generation time depends on the size of the data warehouse.

Abstracting and Indexing↗
PubMed1997

Use of 2% propofol to produce diurnal sedation in critically ill patients.

OBJECTIVE: The assessment of propofol to produce diurnal sedation in critically ill patients. DESIGN: Prospective clinical study. SETTING: Intensive Care Unit, University Hospital. PATIENTS AND PARTICIPANTS: Thirty consecutive patients admitted to the Intensive Care Unit older than 18 years who were expected to be sedated for more than 50 h. INTERVENTIONS: The patients were randomised into two groups. All received sedation with a constant background infusion of morphine and a variable infusion rate of propofol, which was altered hourly to maintain the intended sedation score. The first group received constant light sedation (CLS) over 50 h aiming for a Ramsay score of 2-3. The second group received CLS between 0600 h and 2200 h and additional night sedation (ANS) with propofol between 2200 h and 0600 h, aiming for a sedation score of 4-5. MEASUREMENTS AND RESULTS: Patients were studied for 50 h from 1800 h on the first day of admission. Recordings of heart rate, blood pressure, sedation scores and propofol and morphine infusion rates were made hourly. An APACHE II score was recorded for each patient. Sedation scores were analysed by blind visual assessment and cosinor analysis, which is used in chronobiology to examine the correlation of data with a cosine curve. Patients in the ANS group had significantly better rhythmicity of sedation levels using cosinor analysis (r = 26% v 8%) p < 0.01. There was no difference between the CLS and ANS groups with respect to age, sex or APACHE II scores. Nine out of 15 patients in the ANS group achieved diurnal sedation. Three patients in the CLS group showed diurnal rhythmicity of sedation, which can be attributed to natural sleep, and had a median APACHE II score of 12. Five patients in the CLS group and three in the ANS group showed a deep constant sedation pattern. They had high APACHE II scores (median 21.5) and an obtunded conscious level on admission due to severe sepsis. CONCLUSION: Propofol can safely provide diurnal sedation in the critically ill when titrated against the Ramsay score. Sedation levels cannot be manipulated in some severely ill patients.

APACHE↗
PubMed1997

Propofol 2% in critically ill patients: effect on lipids.

OBJECTIVE: To investigate the concentrations of triglyceride, cholesterol, and high-density lipoprotein during a 50-hr infusion of 2% propofol, starting within 24 hrs of admission to the intensive care unit (ICU). DESIGN: Prospective, clinical study. SETTING: ICU, university hospital. PATIENTS: Thirty adult patients, who were ventilated and expected to be sedated for >2 days, were studied for 50 hrs, beginning at 1800 hrs on the first day of ICU admission. MEASUREMENTS AND MAIN RESULTS: Triglyceride, cholesterol, and high-density lipoprotein were measured at 2000, 0400, and 0800 hrs. Tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and C-reactive protein were measured at 2000 hrs. Median cholesterol and high-density lipoprotein concentrations were at the low end of the normal range. In seven patients, peak triglyceride concentrations were >3 mmol/L up to a maximum of 4.83 mmol/L. Although there was no statistical difference in lipid concentrations between days 1 and 2, there was an apparent pattern of increasing triglyceride concentrations. There was a correlation between peak triglyceride concentration and total propofol consumption, but there was no correlation between lipids and age, gender, or Acute Physiology and Chronic Health Evaluation II scores. There was a direct correlation between triglyceride and C-reactive protein concentrations, and an inverse correlation between cholesterol and C-reactive protein. Twenty-two patients had evidence of TNF and 11 patients had an IL-6 of >1000 pg/mL, but there was no relationship between concentrations of cytokines and triglycerides in plasma. CONCLUSIONS: Infusion of 2% propofol to critically ill patients over a 50-hr period does not result in a significant increase in triglyceride concentrations. Mean cholesterol and high-density lipoprotein concentrations were low throughout the study period. There was a significant direct correlation between triglyceride and C-reactive protein and an inverse correlation between cholesterol and C-reactive protein, suggesting that the changes in lipids in critically ill patients may be partly attributable to the acute-phase response.

APACHE↗
PubMed1997

Communication with TB patients; a neglected dimension of effective treatment?

Previous research has shown that patients who are satisfied with their interactions with a health provider tend to adhere to treatment. This study sets out to investigate the quality of the communication in the interactions between clinic nurses at a Western Cape clinic and newly notified tuberculosis patients. Routine interviews between clinic nurses and tuberculosis patients were video-recorded, transcribed and analysed, using a qualitative instrument devised by the researchers. The interactions were evaluated as being essentially nurse-centred; there was an unequal distribution of control, poor receptivity to the patient and little confirmation of the patient. The nursing staff received a period of training in communication skills. After this training their interviews with patients revealed a significant shift towards a more patient-centred approach, resulting in mutual satisfaction of nurse and patient. Training in communication skills should be introduced at TB clinics, in order to improve patients' adherence to therapy.

Analysis of Variance↗
PubMed1997

Combating tuberculosis--lessons learnt from a rural community project in the Klein Drakenstein area of the Western Cape.

OBJECTIVE: To describe and evaluate a lay worker project designed to enhance the effective control of tuberculosis in a rural/farm setting. DESIGN: A descriptive cohort study using both qualitative and quantitative research methodology. SETTING AND PARTICIPANTS: Farming community in the Klein Drakenstein area of Paarl, Western Cape, with health services provided by the Cape Metropolitan Council. The adherence of patients receiving tuberculosis treatment from 1 January 1993 to 31 December 1995 was analysed. The acceptability of the project was assessed using indepth interviews with key stakeholders. RESULTS: A cohort of 402 tuberculosis patients was included in the study. This cohort was divided into the patients from farms that had participated in the project (intervention group) and those that had not (non-intervention group). The adherence data for children and adults were analysed separately. The adherence rates for children in both groups were the same (RR = 1.00, 95% Cl 0.88-1.14), whereas the adherence rate for the adult intervention group was significantly better than that of the non-intervention group (RR = 1.19, 95% Cl 1.08-1.31). The qualitative component of the investigation indicated a high level of commitment to the intervention from the members of the implementation team, the farm health workers and their employers. The farm health workers described how their role had assisted their communities and had improved their own perceptions of self-efficacy. The close bond that they had developed with the formal health sector had improved the access of the labourers on the farm to primary health care. Although the project had commenced as a tuberculosis initiative, the farm health workers were dealing with a variety of health issues. Their ongoing training was designed to facilitate this development. The formal health sector found their activities facilitated by the easy access that they had with a representative from each farm. The employers were satisfied that the project had increased the cost-effectiveness of their economic endeavours. CONCLUSION: This farm worker project appears to be a model of a well-designed and expertly managed community-based project for tuberculosis control in rural/farm areas.

Adolescent↗
PubMed1997

Shared vision--a health education project designed to enhance adherence to anti-tuberculosis treatment.

SETTING: Two adjacent Cape Town Local Authority health clinics in Cape Town, South Africa, were selected. Clinic A was designated the 'intervention clinic' and Clinic B the 'control clinic.' OBJECTIVE: To assess whether the combined strategy of a patient-centred interview plus the issuing of a patient education booklet would have the effect of increasing the adherence of notified pulmonary tuberculosis (TB) patients to prescribed treatment. DESIGN: A controlled intervention study was implemented using a cohort of the first 60 consecutive patients notified with pulmonary TB at both Clinic A and Clinic B; the patient cohort thus consisted of 120 patients. RESULTS: The risk of patient non-adherence to anti-tuberculosis treatment was significantly reduced at the intervention clinic compared to the control clinic. CONCLUSION: The results of this study indicate the need for further operational research to assist health providers in developing standardised protocols of health education to enhance adherence to treatment in patients who require protracted treatment regimens.

Attitude to Health↗
PubMed1996

Induction of transmitter release at the neuromuscular junction prevents motoneuron death after axotomy in neonatal rats.

Motoneurons to rat hindleg muscles die after neonatal nerve injury. Here we show that increasing transmitter release of motor nerve terminals by treatment with 4-aminopyridine, prior to nerve injury at three days, reduces the extent of motoneuron death. Retrograde labelling of soleus motoneurons was carried out in 10-week-old animals that had their sciatic nerve crushed on one side when they were three days old. Only 20% (+/- 4.2 S.E.M.) of the motoneurons survived the nerve injury. A group of animals similarly injured at three days had their calf muscles treated with 4-aminopyridine at birth, prior to nerve injury. In these animals a significantly higher percentage (51 +/- 6.6% S.E.M.) of soleus motoneurons survived. In order to assess the proportion of surviving alpha-motoneurons only, the number of motor units in both the soleus and extensor digitorum longus muscles was established by following the stepwise increments of twitch tension in response to increasing intensity of stimulation of the respective motor nerve. After nerve injury at three days only 18% (+/- 4.1% S.E.M.) of motor units to soleus and 28.5% (+/- 4.9% S.E.M.) to extensor digitorum longus survived and were able to reinnervate their respective muscles. If the nerve injury was preceded by local application of 4-aminopyridine, then the number of motor units present in the reinnervated muscles was significantly greater, so that in soleus 52.7% (+/- 5.4% S.E.M.) and in extensor digitorum longus 52.1% (+/- 2.4% S.E.M.) of motor units were present. This increase of motoneuron survival was reflected in a smaller weight loss and in a better restoration of force production by the pretreated as compared to untreated muscles on reinnervation after nerve injury. It is suggested that enhancing transmitter release from nerve endings in neonatal animals induces the motoneuron to become more resistant to nerve injury.

4-Aminopyridine↗
PubMed1996

Aminoglycoside levels in the rabbit vitreous cavity after intravenous administration.

PURPOSE: To determine the penetration of gentamicin and amikacin into the rabbit vitreous cavity after their intravenous administration. METHODS: Gentamicin (1.6 mg/kg every 8 hours) and amikacin (6 mg/kg every 12 hours) were administered intravenously to 25 rabbits that had previously had the lens and vitreous removed from 43 eyes. For each drug, ocular inflammation was induced in one group of eyes by injection of heat-killed Staphylococcus epidermidis, while the other group was maintained as a control. Samples from the vitreous cavity were taken at regular intervals for 72 hours after beginning the intravenous medications and were analyzed for drug concentrations. RESULTS: The maximum intravitreal concentration +/- SD achieved for gentamicin was 1.8 +/- 0.5 microgram/ml. The maximum intravitreal concentration for amikacin was 8.5 +/- 3.2 micrograms/ml. Inflamed eyes demonstrated higher concentrations than did those without inflammation. CONCLUSIONS: In a rabbit model with conditions optimized to enhance penetration of antimicrobials into the vitreous cavity after intravenous administration, neither gentamicin nor amikacin penetrated sufficiently to reach potentially therapeutic concentrations consistently for either Pseudomonas or S epidermidis organisms.

Amikacin↗
PubMed1996

Tuberculosis in the community: 1. Evaluation of a volunteer health worker programme to enhance adherence to anti-tuberculosis treatment.

SETTING: A voluntary health worker project (Operation Elsies River) was started in a high incidence tuberculosis (TB) area in the Western Cape of South Africa, in order to assist the local TB Control programme with case-holding. OBJECTIVE: To evaluate the effectiveness of this group of volunteers in enhancing adherence of notified TB patients to tuberculosis treatment. DESIGN: A cohort study was conducted with 351 TB patients (203 children and 148 adults). RESULTS: The data from the child and the adult groups were analysed separately. The child group was more adherent to TB treatment than adults. The supervision option with staff dedicated to the treatment of TB, such as the clinic and the SANTA crèche, achieved better adherence results for pre-school children. The supervision modalities for adults did not differ in their adherence performance even following adjustment for confounders. CONCLUSION: The supervision option provided by the volunteers did not significantly improve the adherence of adult patients to antituberculosis treatment.

Adolescent↗
PubMed1996

Development of a health education booklet to enhance adherence to tuberculosis treatment.

Effective anti-tuberculosis chemotherapy was developed during the 1950's, yet four decades later the cure rates for tuberculosis (TB) worldwide remain unacceptably low. A major reason for the failure to eliminate TB is that many patients with active disease fail to take sufficient anti-tuberculosis medication to render a cure. This paper describes a project designed to involve clinic nurses in the process of exploring how TB patients experience their disease. Information obtained from the qualitative research process was used to develop a photonovel which can be used to supplement the education given to newly diagnosed TB patients.

Health Education↗
PubMed1996

Tuberculosis in the community: 2. The perceptions of members of a tuberculosis health team towards a voluntary health worker programme.

SETTING: A voluntary community health worker programme, in the Western Cape, South Africa, utilizing volunteers to administer directly observed therapy to tuberculosis (TB) patients. OBJECTIVE: This study describes the perceptions of health team members regarding the voluntary community health worker project. DESIGN: A qualitative, participatory research study utilizing focus groups. RESULTS: TB was perceived by the health team to be a stigmatized disease causing some patients to be reluctant to be associated with the TB control programme. Despite the project's dedicated approach to case-holding, volunteers expressed the need to develop skills in providing more comprehensive care. The volunteers appear to administer a more personalized service to TB patients and can bridge the gap between TB patients and the health agency. CONCLUSION: Sustained evaluation and support seem to be a vital tool in integrating a volunteer project into a health team approach. Its effectiveness appears to depend to a large degree on the people involved.

Adult↗
PubMed1995

Blocking of NMDA receptors during a critical stage of development reduces the effects of nerve injury at birth on muscles and motoneurones.

Blocking of NMDA receptors during a critical stage of development reduces the effects of nerve injury at birth on muscles and motoneurones. Injury to the sciatic nerve at birth causes many motoneurones to soleus and extensor digitorum longus (EDL) muscles of rats to die. This is reflected in a reduction of motor units in these muscles. In the soleus only 4 (12.3%) motor units remain while 10 (24.3%) remain in the EDL, showing that soleus alpha motoneurones are more sensitive to nerve injury at birth. Treatment with MK-801, an NMDA receptor blocker, rescues a proportion of motor units in both muscles, so that in the soleus 11 (36%) and in the EDL 17 (42%) of motor units survive. This loss of motor units results in muscle weakness and a reduction in force of both muscles. Treatment with MK-801 reduces the effect of nerve injury, so that muscles of treated animals are stronger and weigh more. Cross-sectional area and muscle fibre number in EDL muscles were assessed and found to be dramatically reduced after nerve injury at birth, so that the area was 20% of control, with only 13% of fibres remaining. Moreover the majority of the remaining EDL muscle fibres which are normally fast are converted into slow type I fibres, with 68% of fibres expressing slow myosin compared with 3% in control EDL muscles. In animals treated with MK-801 only 47% of muscle fibres are lost after nerve injury at birth, hence the area of the muscle is greater (51% of control). The change of muscle phenotype induced by nerve injury is prevented and the muscle fibre composition resembles that of normal EDL muscles in that 4% of muscle fibres express slow myosin compared with 3.5% in control EDL muscles. Thus, blocking NMDA receptors with MK-801 shortly after nerve injury at birth reduces the loss of motor units and this is directly reflected in an improved performance of the affected muscles.

Animals↗
PubMed1995

Vancomycin levels in the vitreous cavity after intravenous administration.

PURPOSE: We studied the effects of inflammation, repeated antibiotic doses, and the surgical status of the eye on penetration of vancomycin hydrochloride into the rabbit vitreous cavity after intravenous administration. METHODS: We studied three anatomic states (phakic, aphakic, and aphakic, vitrectomy-treated eyes) subdividing each into inflamed and noninflamed groups. Intravenous vancomycin hydrochloride (15 mg/kg of body weight) was administered every 12 hours for 48 hours. Eyes were harvested for the assay of vitreous cavity antibiotic levels at various intervals from one to 49 hours. We determined concentrations and calculated mean values and S.E.M. RESULTS: Therapeutic levels were not established in the vitreous cavity at any time period in the two phakic groups. At 25 hours, the inflamed aphakic eyes had concentrations of 5.05 +/- 1.9 micrograms/ml and the control noninflamed aphakic eyes 4.5 +/- 1.23 micrograms/ml; slight increases were found by 49 hours. Concentrations tested in the aphakic, vitrectomy-treated eyes at two, 13, 25, and 49 hours demonstrated progressive increases both in the inflamed eyes (5.4 +/- 2.4 micrograms/ml, 9.64 +/- 4.25 micrograms/ml, 9.2 +/- 3.96 micrograms/ml, 10.34 +/- 4.49 micrograms/ml) and noninflamed eyes (3.52 +/- 2.1 micrograms/ml, 5.4 +/- 1.96 micrograms/ml, 6.8 +/- 2.53 micrograms/ml, 8.7 +/- 5.44 micrograms/ml). CONCLUSIONS: Vitreous vancomycin concentrations in aphakic and aphakic, vitrectomy-treated eyes after intravenous administration exceed the minimal inhibitory concentrations for the usual gram-positive pathogens that create endophthalmitis, suggesting a role for intravenous vancomycin in the treatment of bacterial endophthalmitis.

Animals↗
PubMed1995

Vitreous cavity penetration of ceftazidime after intravenous administration.

PURPOSE: Penetration of ceftazidime, a third generation cephalosporin, into the vitreous cavity after intravenous administration was investigated. METHODS: Because antimicrobial penetration varies with surgical status of the eye and with inflammation, studies were conducted in phakic, aphakic, and aphakic, vitrectomized eyes in both normal and inflamed conditions. Ceftazidime 50 mg/kg was administered every 8 hours and vitreous cavity concentrations were tested at intervals from 2 to 72 hours after the initial dose. RESULTS: No penetration was found into control phakic and aphakic eyes, but drug concentrations were detected in inflamed eyes at 24 hours. Vitreous concentrations of ceftazidime in aphakic, vitrectomized eyes reached levels well above the minimal inhibitory concentration (MIC) for Pseudomonas organisms within 2 hours of intravenous administration in control eyes (8.5 micrograms/ml) and inflamed eyes (35.4 micrograms/ml). Inflammation and removal of the lens and vitreous significantly enhanced ceftazidime penetration at all time periods tested. CONCLUSION: Ceftazidime penetrates into the vitreous cavity of inflamed eyes after intravenous administration and achieves concentrations above the MIC for Pseudomonas organisms. Penetration is greatest in aphakic, vitrectomized eyes.

Animals↗
PubMed1995

Percutaneous cholecystolithotomy: risks, benefits, and long-term outcome.

BACKGROUND: For symptomatic patients with gallbladder stones and a patent cystic duct who wish to retain their 'functioning' gallbladders, percutaneous cholecystolithotomy (PCCL) offers an alternative to open or laparoscopic cholecystectomy. However, there are few data on the risks and benefits of this approach or on the long-term outcome. METHODS AND RESULTS: In 21 patients with symptomatic calcified gallstones, PCCL was successful (gallstone clearance) in 17 (81%). Four to 62 (median, 35) months after clearance 9 of the 17 remained symptom-free and stone-free, whereas 4 developed biliary sludge at 7, 30, 32, and 35 months, 2 of whom subsequently developed gallstones. In four other patients gallstones recurred without evidence of preceding biliary sludge at 9, 16, 19, and 27 months, corresponding to an actuarial gallstone recurrence rate at 36 months of 53.4 +/- SEM 15.1%, and a combined stone/sludge recurrence rate of 63.4 +/- 13.5%. CONCLUSIONS: PCCL is moderately effective but, because of the frequency of complications and sludge/stone recurrence, is likely to have only a limited residual role in the era of laparoscopic cholecystectomy.

Cholecystostomy↗