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Biomedical subjects

D Armstrong

Publications and source records attributed to D Armstrong.

At least 325 records · Page 18Linked to original sources
PubMed1992

Cryptococcal meningitis: outcome in patients with AIDS and patients with neoplastic disease.

A retrospective analysis of 41 patients with cryptococcal meningitis and AIDS or neoplastic disease was done. Patients with AIDS were younger and predominantly male; they had a shorter duration of prior illness, higher initial serum cryptococcal antigen titers, and lower initial cerebrospinal fluid white blood cell counts than those with neoplastic disease. The median overall survival for patients with AIDS was 9 months compared with 2 months for those with neoplastic disease (P = .004). Seventy-eight percent of patients with AIDS and 43% of those with neoplastic disease were cured or improved 6 months after diagnosis (P = .039). Toxicity from amphotericin B and flucytosine was similar for both groups. One patient with AIDS relapsed. Multivariate predictors of survival included headache (P = .007) and an AIDS diagnosis (P = .009). Examination of outcomes for other opportunistic infections associated with AIDS and other immunosuppressive illness may distinguish prognostic features for different patient populations.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Comparisons of anti-human immunodeficiency virus activities, cellular transport, and plasma and intracellular pharmacokinetics of 3'-fluoro-3'-deoxythymidine and 3'-azido-3'-deoxythymidine.

3'-Fluoro-3'-deoxythymidine (FLT), a candidate anti-AIDS compound in clinical trials, showed anti-human immunodeficiency virus type 1 (HIV-1) potency (50% effective concentration, 0.0052 microM) slightly better than or equal to that of 3'-azido-3'-deoxythymidine (AZT) in MT4 cells and was threefold more potent in H9 cells. There was no FLT resistance demonstrable in the AZT-resistant HIV-1 strains. Both FLT and AZT showed low cytotoxicity for MT4 cells, with selectivity indices (efficacy/toxicity ratio) of greater than 47,000 and greater than 33,000, respectively. Cellular permeation of FLT and thymidine (dThd) was greater than that of AZT, and FLT and dThd permeated the cell membranes by a carrier-mediated mechanism as well as by simple diffusion, as indicated by the existence of nitrobenzylthioinosine-5'-monophosphate-sensitive and -insensitive components. By contrast, transport of AZT into cells was by simple diffusion. The intracellular level of the triphosphate of FLT (FLTTP) in MT4 cells was two- to threefold higher than that of AZT (AZTTP) after exposure to 1.8 microM each compound for 12 h. The elimination kinetics of FLTTP and AZTTP in HIV-1-infected MT4 cells in fresh medium showed biphasic patterns, with initial half-lives of 1.03 and 1.09 h, respectively. In phytohemagglutinin-stimulated human peripheral blood lymphocytes, the FLTTP level was increased 59-fold compared with that in unstimulated cells at 12 h, was four- to sixfold higher than the level of AZTTP in stimulated cells at 12 h, and remained four- to fivefold higher during a 4-h elimination period in fresh medium and twofold higher at the end of a 12-h elimination period. Two- to eightfold more [3H]AZT than [3H]FLT was incorporated into the host cell DNA, and both [3H]AZT and [3H]FLT remained persistently incorporated for over 24 h. The incorporated [3H]AZT and [3H]FLT were alkali labile, whereas incorporated [3H]dThd was alkali stable. Pharmacokinetics of FLT in plasma of monkeys after intravenous (i.v.) administration showed that the FLT concentration in plasma declined, with a half-life of 1.19 +/- 0.1 h; the steady-state volume of distribution was 0.93 +/- 0.2 liter/kg of body weight, and total clearance was 0.56 +/- 0.15 liter/kg. Oral bioavailability of FLT was excellent and comparable to i.v. bioavailability in terms of areas under the concentration-time curves for three monkeys. Of the total dose, 41 to 61% was excreted in urine as unchanged FLT, and only 3.2 to 7.4% of the total dose was identified as glucuronide-conjugated FLT in urine 48 h after i.v. administration to monkeys. We conclude that FLT exhibits an anti-HIV-1 potency similar to that of AZT but with slightly better selectivity of effects and with higher intracellular active metabolite levels.

Animals↗
PubMed1992

Development of clinical guidelines in a health district: an attempt to find consensus.

OBJECTIVE: To formulate consensus based guidelines for antenatal care in a health district. DESIGN: Prospective formulation of draft guidelines by a working group of consultant obstetricians and general practitioners with an obstetric interest, canvassing opinions of all GPs in the district by questionnaire, and revision and final circulation of the guidelines. SETTING: One health district. SUBJECTS: All 160 GPs in the district and members of the working party. MAIN MEASURES: Questionnaire responses to specific proposals within the draft guidelines for managing anaemia, antepartum haemorrhage, and hypertension. RESULTS: 136 GPs responded (response rate 85%); responders and nonresponders did not differ in age, sex, or presence on obstetric list. Overall they favoured more conservative management than suggested in the guidelines. For example, only 38% (44/116) prescribed iron routinely and 34% (38/113) referred to hospital for haemoglobin concentration of < or = 10 g/l; 10% referred women unnecessarily for oedema unassociated with proteinuria; and 20% managed active bleeding progressing to old brown staining as an urgent admission. The guidelines were revised according to the relative weight of the views obtained. CONCLUSION: Establishing guidelines is mainly a political process. Canvassed views influenced guidelines most when internal disagreement existed within the working party. IMPLICATIONS AND ACTION: Regular revising of the guidelines is planned, which, in conjunction with repeating the questionnaire to monitor changing practice, will allow a long term district wide clinical review.

Attitude of Health Personnel↗
PubMed1992

Comparison of azoles against aspergilli in vitro and in an experimental model of pulmonary aspergillosis.

Current treatment modalities for bronchopulmonary aspergillosis are not very satisfying. We determined the in vitro activity of recently available azoles against Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger. Subsequently, these agents were evaluated in an animal model of bronchopulmonary aspergillosis using A. fumigatus as test organism. In vitro, detectable activity was only found for itraconazole (all minimal inhibitory concentrations, MICs, less than or equal to 3.2 micrograms/ml). The MICs for SCH39304 were greater than or equal to 12.8 micrograms/ml and greater than or equal to 25.6 micrograms/ml for ketoconazole and fluconazole. In vivo, amphotericin B was the most active agent tested, and SCH39304 was the most active azole in terms of survival and reduction in lung weight, followed by itraconazole. Ketoconazole and fluconazole did not improve survival nor reduce the lung weight of infected animals. We conclude, (1) that in vitro activity of azoles against aspergilli does not always correlate with in vivo activity; (2) that in vivo, SCH39304 was the most active azole tested, followed by itraconazole; (3) that for those agents for which data about effectiveness in human pulmonary aspergillosis are available (amphotericin B, ketoconazole, itraconazole) antifungal activity in our model corresponds to activity as seen in human beings, and (4) that SCH39304 and itraconazole are rational choices for clinical trials in human pulmonary aspergillosis.

Amphotericin B↗
PubMed1992

Cranio-orbito-zygomatic measurements from standard CT scans in unoperated Crouzon and Apert infants: comparison with normal controls.

Cranio-orbito-zygomatic measurements taken from standard axial computed tomographic (CT) scans of unoperated patients with Crouzon syndrome (6 males, 14 females) and Apert syndrome (6 males, 10 females) under 1 year of age were compared to each other and to normal controls (40 males, 35 females). Fifteen cranio-orbito-zygomatic variables were measured and repeated. Means and standard deviations were computed for each sex, and means were pooled since they were not significantly different. Correlation coefficients for repeat measures (intra-observer error) of each variable showed good reproducibility. Only the lateral orbital wall angle differed between the syndromes (p = .034), suggesting that upper facial differences (as measured by these variables) do not manifest themselves at this young age. All measurements for both syndromes, except one, were outside the 95 percent confidence range for age-matched controls. Measurements taken from standard CT scans provide an objective comparison between specific syndromes and the normal population.

Acrocephalosyndactylia↗
PubMed1992

Oesophageal pH-metry: should meals be standardized?

To assess the effect of a late-evening, high-fat meal on nocturnal supine gastro-oesophageal reflux, eight healthy volunteers (aged 20 to 38 years) underwent two ambulatory oesophageal pH-metry recordings, the first after a standardized light meal at 1930 h and the second after a high-fat meal including peppermint and chocolate, at 2130 h. Between 2300 and 0700 h, when subjects were supine, the median acid exposure time (percentage recording with pH less than 4) increased from 0.0% (range, 0.0-6.8%) after the standardized meal to 7.9% (0.0-17.8%) after the high-fat meal (p = 0.031). Similarly, the median number of reflux episodes increased from 0 (0 to 11) after the standardized meal to 7 (0 to 26) after the high-fat meal (p = 0.031). Reflux occurred after both meals, but, in general, persistent nocturnal reflux was observed only after the high-fat meal. Thus, the analysis of oesophageal pH recordings should consider the effects of meal composition and timing on oesophageal acid exposure.

Adult↗
PubMed1992

Influence of stress on the healing and relapse of duodenal ulcers. A prospective, multicenter trial of 2109 patients with recurrent duodenal ulceration treated with ranitidine. RUDER Study Group.

The influence of psychologic factors on the healing and relapse of duodenal ulcers under treatment with ranitidine was studied in a prospective, multicenter trial in 2109 patients with an endoscopically proven duodenal ulcer (DU) and a history of recurrent duodenal ulceration. All patient received ranitidine (300 mg daily), and, after healing, 1899 patients continued maintenance treatment (ranitidine, 150 mg daily) for 2 years. A physician's assessment of stress (stress or no stress) was made at every consultation. In the healing phase an overall classification of stress as absent, intermittent, or continuous was made, and in the maintenance phase patients were classified dichotomously as having stress (stress on at least half of the follow-up consultations) or no stress. In addition, at the start of the healing phase stress was measured by means of a standardized questionnaire. Continuous stress, as assessed by the physicians, was associated with a lower 14-day healing rate (35.7%) than intermittent or absent stress (42.4%; relative risk (RR) for delayed healing in patients with continuous stress, 1.19; 95% confidence interval (CI), 1.06-1.33; P < 0.02). Differences in the 14-day healing rate for patients with low and moderate stress scores (43.1%) compared with those with high and very high stress scores (37.9%) just failed to reach statistical significance (RR for patients with stress, 1.14; 95% CI, 0.998-1.29; P = 0.051). During the 1st year of maintenance treatment 18.3% of patients with stress, but 10.9% of patients without stress, had a DU relapse (RR of stress for DU relapse during the first year, 1.73; 95 CI, 1.44-2.09; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Evaluating two different evaporative cooling management systems for dairy cows in a hot, dry climate.

Milk production, rectal temperature, live weight gain, reproductive performance, and weather data were obtained on 150 Holstein cows managed under two cooling systems on a large dairy farm in Saudi Arabia during the summer months. Cows were paired at the onset of the trial according to days postpartum, lactation number, and current milk production. Females were then allocated either to a system that forced air, precooled by evaporative cooling, over the cows or to a system that alternately showered a fine mist onto the surface of the cows and then forced air at ambient temperature over them. The cows receiving evaporative cooling and those with spray and fan cooling were on sand and on slatted concrete floor, respectively, during the periods of cooling. The onset of estrus was observed during the night when the cows preferred the unshaded corral. For the 120-d trial period, 84% (62 of 75) of the cows receiving evaporative cooling and 60% (44 of 75) of the cows receiving spray and fan cooling became pregnant. In the evaporative cooling system, the pregnancy rate per insemination was 35.2% (179 inseminations) versus 23.2% (194 inseminations) for spray and fan cooling. The mean postpartum interval to pregnancy was 117.6 d for the evaporative cooling cows and 146.7 d for spray and fan cooling cows. The evaporative cooling system, with its open shades and sand bedding, enhanced reproductive performance and milk production compared with that of cows cooled with a spray and fan system with slatted flooring in this hot climate.

Air Conditioning↗
PubMed1992

Early clinical results with the hydroxyapatite-coated porous LSF Total Hip System.

The design of and early clinical results with the uncemented porous-coated LSF Anatomic and Midstem Total Hip Systems are described. In a Food and Drug Administration-approved program, a random selection method was used to determine which patients receive implants with a hydroxyapatite (HA) coating applied to the porous surface and which patients receive non-HA-coated implants. The early clinical results with the HA-coated systems appear superior to the non-HA-coated systems. A greater percentage of patients with HA systems have clinical scores in the excellent/good range, which is primarily a reflection of less prosthesis-related pain. Radiographically, all components appear well fixed with evidence of bone ingrowth. The HA-coated systems have a decreased incidence of radiolucencies, particularly in proximal zones.

Durapatite↗
PubMed1992

Presbycusis: correlations of clinical audiology with morphological changes in the cochlea and the ventral cochlear nucleus.

Five cases of presbycusis are presented. Analysis included audiological tests, cochlear hair cell and ganglion cell counts, assessment of degree of strial atrophy, and ventral cochlear nucleus neuron counts. One case showed a reduction in cochlear nucleus neuron counts without significant cochlear changes, indicating that this pattern of pathological changes is a possible cause of high tone sensorineural deafness.

Aged↗
PubMed1992

[Prevention of recurrence of ulcer disease: indications and choice of procedure].

In this contribution we discuss the relapse prophylaxis of ulcers by nonmedicamentous measures, by long-term drug therapy and, in particular, with inhibitors of secretion, by eradication therapy of Helicobacter pylori and by surgical therapy. Besides secondary prophylaxis (prevention of ulcer relapses), primary prophylaxis (prevention of the first episode) is also briefly treated.

Anti-Ulcer Agents↗
PubMed1992

Inappropriate reattendances in out-patient departments.

In an attempt to identify the number and characteristics of inappropriate reattendances at out-patient clinics, clinic doctors and patients in two specialties throughout a health district were given a questionnaire to complete on every patient attendance over one week. Four hundred and fifty-two patients were seen, and 293 were asked to reattend: in some 80 of the latter cases the clinic doctor felt that the GP could nevertheless manage the problem. These 'inappropriate' invitations to reattend were more likely to be given by junior hospital staff to long-standing patients of the clinic attending for monitoring purposes. The patients involved in these 'inappropriate' requests to reattend also tended to think that their GP could manage the problem. It is concluded that discharge policy needs to be made more explicit and training for juniors organized if out-patient resources are to be used most efficiently.

Health Services Misuse↗
PubMed1992

Diagnostic assessment of gastroesophageal reflux disease: what is possible vs. what is practical?

The diagnosis of gastroesophageal reflux disease (GERD) entails the identification of patients with esophagitis and its complications as well as patients who have symptoms but no mucosal disease. Endoscopy is mandatory to establish a diagnosis of reflux esophagitis, to exclude other esophageal disease and to permit directed biopsy if columnar metaplasia, dysplasia or carcinoma is suspected. The lesions of reflux esophagitis--erosions, ulceration, stricturing and metaplasia--should be identified and graded independently, using a classification system such as the recently described "MUSE" (Metaplasia, Ulcer, Stricture, Erosions) system. Fluoroscopy can identify associated structural changes such as stricturing or esophageal shortening. Measures of esophageal acid exposure time may be used to quantify reflux before and after treatment; however, if the patient has typical symptoms but no esophagitis, a temporal association between symptoms and episodes of esophageal acidification should be sought. Ambulatory 24-hour esophageal pH-monitoring with accurate event-marking provides recordings suitable for an objective statistical analysis, which was evaluated prospectively in 14 patients. Computerized analysis of 24-hour esophageal pH recordings diagnosed 5 patients as having acid-related symptoms although only 3 of 5 patients fulfilling the criteria for pathological reflux had pH-related chest pain. This finding was confirmed by 5 experts who analyzed all recordings visually, unaware of the result of the computer analysis. The Bernstein test should be reserved for patients whose symptoms are too infrequent to permit an objective assessment of symptom occurrence during pH monitoring. In conclusion, i) endoscopy is the test of choice for the diagnosis of esophagitis but it should be supplemented by a standardized and reliable scoring system for disease severity; ii) ambulatory esophageal pH recording with accurate event-marking is the test of choice for the diagnosis of GER-related symptoms, but it should be supplemented by an objective assessment of the temporal relationship between symptoms and esophageal pH; and iii) esophageal manometry is the test of choice for evaluating esophageal peristalsis and LES (lower esophageal sphincter) function but, in the context of GERD, its main indication is the assessment of GERD patients who are being considered for surgery. The widespread use of other tests for clinical purposes must await a better understanding of the pathophysiological mechanisms which can lead to the development of GERD.

Esophagitis, Peptic↗
PubMed1992

Indirect intracranial volume measurements using CT scans: clinical applications for craniosynostosis.

This paper describes a method for obtaining indirect intracranial volume measurements using CT scans with CTpak, a software package for quantitative analysis of CT scan data. The validity of this technique was confirmed by comparing direct measurement of the intracranial volume of five dry skulls with axial scans at 1.5- and 4-mm slice intervals to determine indirect volume. The indirect intracranial volume measurement technique was then used to compare preoperative and postoperative intracranial volume in 30 patients with craniosynostosis who underwent cranial vault and orbital osteotomies with reshaping and advancement. Our findings show that the suture release and simultaneous reshaping procedures usually carried out are, in fact, associated with increased intracranial volume. The observed intracranial volume gain is attributable to a combination of factors, including the surgical procedure carried out and ongoing growth. These factors are further modified by the diagnosis, age of the patient, and time interval between CT scans.

Age Factors↗