Enzymatic cleaving of entangled DNA rings drives scale-dependent rheological trajectories

DNA, which naturally occurs in linear, ring, and supercoiled topologies, frequently undergoes enzyme-driven topological conversion and fragmentation in vivo, enabling it to perform a variety of functions within the cell. In vitro, highly concentrated DNA polymers form entanglements that yield viscoelastic properties dependent on the topologies and lengths of the DNA. Enzyme-driven alterations of DNA size and shape therefore offer a means of designing active materials with programmable viscoelastic properties. Here, we incorporate multi-site restriction endonucleases into dense DNA solutions to linearize and fragment circular DNA molecules. We pair optical tweezers microrheology with differential dynamic microscopy and single-molecule tracking to measure the linear and nonlinear viscoelastic response and transport properties of entangled DNA solutions over a wide range of spatiotemporal scales throughout the course of enzymatic digestion. We show that, at short timescales, relative to the relaxation timescales of the polymers, digestion of these 'topologically-active' fluids initially causes an increase in elasticity and relaxation times followed by a gradual decrease. Conversely, for long timescales, linear viscoelastic moduli exhibit signatures of increasing elasticity. DNA diffusion, likewise, becomes increasingly slowed, in direct opposition to the short-time behavior. We hypothesize that this scale-dependent rheology arises from the population of small DNA fragments, which increases as digestion proceeds, driving self-association of larger fragments via depletion interactions, giving rise to slow relaxation modes of clusters of entangled chains, interspersed among shorter unentangled fragments. While these slow modes likely dominate at long times, they are presumably frozen out in the short-time limit, which instead probes the faster relaxation modes of the unentangled population.

Optical-Tweezers-integrating-Differential-Dynamic-Microscopy maps the spatiotemporal propagation of nonlinear strains in polymer blends and composites

How local stresses propagate through polymeric fluids, and, more generally, how macromolecular dynamics give rise to viscoelasticity are open questions vital to wide-ranging scientific and industrial fields. Here, to unambiguously connect polymer dynamics to force response, and map the deformation fields that arise in macromolecular materials, we present Optical-Tweezers-integrating-Differential -Dynamic-Microscopy (OpTiDMM) that simultaneously imposes local strains, measures resistive forces, and analyzes the motion of the surrounding polymers. Our measurements with blends of ring and linear polymers (DNA) and their composites with stiff polymers (microtubules) uncover an unexpected resonant response, in which strain alignment, superdiffusivity, and elasticity are maximized when the strain rate is comparable to the entanglement rate. Microtubules suppress this resonance, while substantially increasing elastic storage, due to varying degrees to which the polymers buildup, stretch and flow along the strain path, and configurationally relax induced stress. More broadly, the rich multi-scale coupling of mechanics and dynamics afforded by OpTiDDM, empowers its interdisciplinary use to elucidate non-trivial phenomena that sculpt stress propagation dynamics-critical to commercial applications and cell mechanics alike.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Structure-Activity Relationships of Novel Thiazole-Based Modafinil Analogues Acting at Monoamine Transporters

Atypical dopamine reuptake inhibitors, such as modafinil, are used for the treatment of sleeping disorders and investigated as potential therapeutics against cocaine addiction and for cognitive enhancement. Our continuous effort to find modafinil analogues with higher inhibitory activity on and selectivity toward the dopamine transporter (DAT) has previously led to the promising thiazole-containing derivatives CE-103, CE-111, CE-123, and CE-125. Here, we describe the synthesis and activity of a series of compounds based on these scaffolds, which resulted in several new selective DAT inhibitors and gave valuable insights into the structure-activity relationships. Introduction of the second chiral center and subsequent chiral separations provided all four stereoisomers, whereby the S-configuration on both generally exerted the highest activity and selectivity on DAT. The representative compound of this series was further characterized by in silico, in vitro, and in vivo studies that have demonstrated both safety and efficacy profile of this compound class.

Spatially resolved single crystal x-ray spectropolarimetry of wire array z-pinch plasmas

A recently developed single-crystal x-ray spectropolarimeter has been used to record paired sets of polarization-dependent and axially resolved x-ray spectra emitted by wire array z-pinches. In this measurement, two internal planes inside a suitable crystal diffract the x-rays into two perpendicular directions that are normal to each other, thereby separating incident x-rays into their linearly polarized components. This paper gives considerations for fielding the instrument on extended sources. Results from extended sources are difficult to interpret because generally the incident x-rays are not separated properly by the crystal. This difficulty is mitigated by using a series of collimating slits to select incident x-rays that propagate in a plane of symmetry between the polarization-splitting planes. The resulting instrument and some of the spatially resolved polarized x-ray spectra recorded for a 1-MA aluminum wire array z-pinch at the Nevada Terawatt Facility at the University of Nevada, Reno will be presented.

A pilot study quantifying the shape of tidal breathing waveforms using centroids in health and COPD

During resting tidal breathing the shape of the expiratory airflow waveform differs with age and respiratory disease. While most studies quantifying these changes report time or volume specific metrics, few have concentrated on waveform shape or area parameters. The aim of this study was to derive and compare the centroid co-ordinates (the geometric centre) of inspiratory and expiratory flow-time and flow-volume waveforms collected from participants with or without COPD. The study does not aim to test the diagnostic potential of these metrics as an age matched control group would be required. Twenty-four participants with COPD and thirteen healthy participants who underwent spirometry had their resting tidal breathing recorded. The flow-time data was analysed using a Monte Carlo simulation to derive the inspiratory and expiratory flow-time and flow-volume centroid for each breath. A comparison of airflow waveforms show that in COPD, the breathing rate is faster (17 ± 4 vs 14 ± 3 min(-1)) and the time to reach peak expiratory flow shorter (0.6 ± 0.2 and 1.0 ± 0.4 s). The expiratory flow-time and flow-volume centroid is left-shifted with the increasing asymmetry of the expired airflow pattern induced by airway obstruction. This study shows that the degree of skew in expiratory airflow waveforms can be quantified using centroids.

Epidemiological features of drug resistant tuberculosis in Harare, 1994 to 1996

OBJECTIVES

To characterise the prevalence, clinical and radiological features of drug resistant tuberculosis in selected patients with pulmonary tuberculosis in Harare between 1994 and 1996.

DESIGN

A retrospective review of medical and microbiological records.

SETTING

Beatrice Road Infectious Diseases Hospital, Harare, Zimbabwe.

SUBJECTS

381 smear-positive tuberculosis patients who had samples submitted to the National Tuberculosis Reference Laboratory for culture and susceptibility testing.

MAIN OUTCOME MEASURES

Prevalence of resistance of isolated cultures of Mycobacterium tuberculosis to anti-tuberculosis drugs; clinical, radiological and microbiological response to treatment with recommended anti-tuberculosis regimens.

RESULTS

Resistance to one or more drugs was detected in 16 isolates (16/165, 9.7%), single drug resistance in five (3.0%) and resistance to two or more drugs in 11 (6.7%). There were no distinctive clinical or radiological features of drug-resistant tuberculosis, although a higher percent of drug resistant cases had evidence of pleural disease (25% vs 2.5%, p = 0.005). Neither past history of tuberculosis or known or suspected HIV infection was associated with the presence of drug resistance.

CONCLUSIONS

In spite of the resurgence of tuberculosis and the high prevalence of HIV infection in Zimbabwe, the rates of drug resistance have remained relatively low, even among a selected population at high risk of resistance. A significant proportion of cases of drug-resistant tuberculosis appear to be due to new transmission of drug resistant strains, which reinforces the importance of maintaining a surveillance system for the monitoring of drug susceptibility. Ongoing prospective studies should provide more reliable estimates of the prevalence and determinants of drug resistance in Zimbabwe.

Tuberculous pericardial effusion associated with HIV infection: a sign of disseminated disease

OBJECTIVE

To determine whether tuberculous pericardial effusion is associated with HIV infection.

DESIGN

Retrospective cohort study.

SETTING

Harare, Zimbabwe.

SUBJECTS

61 consecutive patients presenting with tuberculous pericarditis over an 18 month period.

RESULTS

Tuberculous pericarditis was significantly associated with HIV seropositivity (odds ratio [OR] 2.46, 95% confidence interval [CI] 1.4-4.3, P = 0.001). The combination of tuberculous pericarditis and tuberculosis at another clinically obvious site (disseminated disease) was more common than pericarditis alone, and was significantly associated with HIV seropositivity (OR 6.1, CI 1.5-25, P = 0.007). Patients with disseminated disease were usually in CDC stage IV prior to the diagnosis of their tuberculosis.

The association of tuberculosis and HIV infection in Harare, Zimbabwe

SETTING

The tuberculosis (TB) service responsible for all TB treatment in Harare, Zimbabwe.

OBJECTIVES

(1) To determine HIV seroprevalence among TB patients and controls. (2) To compare clinical and demographic characteristics of HIV-infected and uninfected TB patients.

DESIGN

Cohort study. Entry criterion: TB diagnosed during the 18 month study period. Assessment included HIV serology. Matched community controls were HIV serotested.

RESULTS

In 1434 TB patients tested, HIV seroprevalence was 48% in men and 44% in women, peaked in the 25-34 year age group and was higher than in controls (relative risk [RR] = 3.1, 95% confidence interval [CI] = 2.6-3.7). In adults, seroprevalence was 34%, 49% and 58% in successive 6 month periods. A history of entry of prior TB treatment was less common in the HIV-seropositive (RR = 0.57, CI = 0.37-0.88). In adults, tuberculin negativity, TB at 2 sites, lymph node, pericardial and miliary TB, hilar adenopathy and pleural effusion were significantly more common in HIV-seropositive patients; cavitation and upper lobe involvement were significantly less frequent. Pulmonary TB and sputum smear positivity had similar frequencies in the 2 groups.

CONCLUSION

HIV was strongly and increasingly associated with TB in Harare and altered the clinical and radiologic features of TB. Failed standard TB treatment in HIV-infected individuals contributed minimally to new cases of TB.

Antihypertensive effects of low doses of hydrochlorothiazide in hypertensive black Zimbabweans

The antihypertensive effects of low doses of hydrochlorothiazide have not been examined in black African hypertensive patients although hydrochlorothiazide is commonly used as first-line therapy. The antihypertensive effects of hydrochlorothiazide in a daily dose of 6.25, 12.5, 25 and 50 mg were examined in 19 black Zimbabwean hypertensive patients in a double-blind, random order, placebo-controlled, cross-over trial. The mean systolic blood pressure on placebo was 170.2 mmHg (95% CI +/- 9.0 mmHg) and on daily doses of hydrochlorothiazide decreased to: 161.1 mmHg (95% CI + 10.0 mmHg) on 6.25 mg; 156.6 mmHg (95% CI +/- 8.6 mmHg) on 12.5 mg; 154.9 mmHg (95% CI +/- 8.5 mmHg) on 25 mg and 149.1 mmHg (95% CI +/- 9.2 mmHg) on 50 mg. The mean diastolic blood pressure on placebo was 101.4 mmHg (95% CI +/- 5.0 mmHg) and decreased to: 98.0 mmHg (95% CI +/- 5.7 mmHg) on 6.25 mg; 96.1 mmHg (95% CI +/- 4.5 mmHg) on 12.5 mg; 93.6 mmHg (95% CI +/- 5.3 mmHg) on 25 mg and 90.5 mmHg (95% CI +/- 3.9 mmHg) on 50 mg. Hydrochlorothiazide in doses of 25 mg and 50 mg decreased systolic and diastolic blood pressure and the 12.5 mg dose decreased systolic blood pressure significantly more than placebo. We conclude that in this population maximum antihypertensive effect is not seen with the lower doses of hydrochlorothiazide and 25 mg is an appropriate starting dose for most patients.

Pulmonary Kaposi's sarcoma in Africa

BACKGROUND

A study was carried out to identify the main clinical radiological and bronchoscopic features of HIV related Kaposi's sarcoma of the lung in African patients.

METHODS

Forty seven HIV positive patients with epidemic Kaposi's sarcoma who had clinical or radiological respiratory changes were investigated by simple lung function tests and fibreoptic bronchoscopy.

RESULTS

The most common respiratory symptoms in the 47 patients were persistent cough in 42, haemoptysis in 23, and breathlessness in 38. A restrictive spirometric pattern was most common. The mean (SD) forced expiratory volume in one second (FEV1) was 1.88 (0.62) 1 with a forced vital capacity (FVC) of 2.66 (0.87) 1 and a FEV1/FVC% of 73.2 (7.5). On the chest radiograph 26 patients had diffuse reticulonodular shadows, 11 focal nodular shadows, seven a pleural effusion, and one a substantial increase in vascular markings; in two the radiograph was normal. At bronchoscopy characteristic discrete lesions were easily visible in 37 patients and were often bright red. Multiple nodules were seen in 11, flat or early plaque lesions in 12 (14 had both), proximal flat lesions and diffuse infiltration in three, diffuse infiltration alone in four, and masses in two; one had normal appearances at bronchoscopy. One patient had Pneumocystis carinii and two had a single bacterial pathogen cultured from the bronchoalveolar lavage fluid. Only two of 29 bronchoscopic biopsies showed classical histological Kaposi's sarcoma. After cytotoxic treatment 20 patients have died, with an overall median survival of 70 days.

CONCLUSION

In this African population symptomatic pulmonary Kaposi's sarcoma was common, with lesions seen in all but one patient at bronchoscopy. Coexistent infection was uncommon. Prognosis was poor despite treatment.

A comparative study of the schizontocidal efficacy and safety of artemether versus chloroquine in uncomplicated malaria

Forty-seven patients with uncomplicated falciparum malaria were randomly assigned to receive either artemether (n = 24), 9.6 mg/kg body weight intramuscularly over five days or chloroquine (n = 23), 25 mg/kg body weight orally. Patients were kept in hospital for seven days followed by review on days 14, 21 and 28. Five patients on chloroquine were withdrawn before day seven due to treatment failure. Of the remaining patients, parasite clearance time was 33.0 +/- 13.6 hours for the artemether group and 63.3 +/- 14.7 hours for patients on chloroquine (p < 0.001). No significant difference was recorded in fever clearance time between the two groups of patients. Recrudescence rate for patients on artemether was 14.3 pc compared to 57.1 pc for the chloroquine group (p < 0.05). No major adverse events were recorded for either treatment group although five patients on artemether had a transient spike of temperature after clearance of parasitaemia. In conclusion, our study has shown that no major adverse events were experienced by patients on artemether and the rate of parasite clearance for the artemether group was superior to that of patients on chloroquine.

Blastomycosis in Africa: clinical features, diagnosis, and treatment

Four cases of blastomycosis seen in two acute care hospitals in Harare, Zimbabwe, are described. All patients had symptoms of at least 2 months' duration before presentation, and all had radiographic evidence of pulmonary consolidation. Three patients had confirmed bone involvement, and two had chronic discharging sinuses. The features of blastomycosis in Africa are reviewed, and problems of diagnosis and treatment are discussed. It is concluded that blastomycosis in Africa may often be misdiagnosed as tuberculosis or pyogenic infection in the absence of adequate facilities for mycologic investigation.

Comparison of the prevalence of reversible airways obstruction in rural and urban Zimbabwean children

The prevalence of reversible airways obstruction has been assessed in children in three areas in Zimbabwe--northern Harare (high socioeconomic class urban children), southern Harare (low socio-economic class urban children), and Wedza Communal Land (rural children from peasant families). Peak expiratory flow (PEF) was measured before and after six minutes' free running in 2055 Zimbabwean primary school children aged 7-9 years. Height and weight were measured and nutritional state expressed as a percentage of the 50th centile for age (Tanner-Whitehouse standards). Reversible airways obstruction was deemed to be present when peak expiratory flow was below the 2.5th centile for height before exercise and rose by more than 15% after inhalation of salbutamol and when it fell by 15% or more after exercise and rose again after salbutamol. The prevalence of reversible airways obstruction was 5.8% (95% confidence interval 4.1-7.5%) in northern Harare (n = 726); 3.1% (1.8-4.5%) in southern Harare (n = 642), and 0.1% (0.0-0.4%) in Wedza (n = 687). In northern Harare, the only study area in which white children were found, the prevalence of reversible airways obstruction was similar in white (5.3%, 10/188) and black (5.9%, 32/538) children. Indicators of nutritional state also showed no significant differences between white and black children in northern Harare but were lower in southern Harare and lower still in Wedza. Urban living and higher material standards of living appear to be associated with a higher prevalence of reversible airways obstruction in children in Zimbabwe.

Variation in cuff blood pressure in untreated urban outpatients with mild hypertension in Harare, Zimbabwe--implications for the diagnosis of hypertension

Duplicate measurements of BP were recorded at six visits in 32 male urban factory workers found to have raised BP (systolic blood pressure (SBP) greater than or equal to 160 mmHg or diastolic blood pressure (DBP) greater than or equal to 90 mmHg) at the initial visit). A systematic decrease in both SBP and DBP occurred over the first three visits. The BP at visits 4-6 was not significantly different. Most of the decrease in BP occurred between the first and second visit (mean SBP decreased 8.5 mmHg and mean DBP decreased 11.1 mmHg). After 6 visits 66% of subjects could be classified into clear clinical groups (normotensive 53.5%, hypertensive 12.5%) but in 34% the variation in cuff BP precluded classification. In these subjects prolonged observation or home BP monitoring may be required before initiating lifelong treatment.

A comparison of inhaled beclomethasone dipropionate and nedocromil sodium as additional therapy in asthma

We have compared the effects of inhaled beclomethasone dipropionate (BDP) 400 micrograms day-1 with inhaled nedocromil sodium (NDS) 16 mg day-1 as additional therapy in adults with asthma not fully controlled by regular beta-2-agonist inhalers with, or without, oral theophyllines. Seventeen subjects were entered into a 2-week baseline phase, and subsequently in a double-blind crossover fashion into two 8-week phases of daily BDP or NDS. Subjects recorded daily peak expiratory flow rates, morning and evening (PEF am and pm), symptom scores and beta-2-agonist inhaler use. Thirteen subjects completed the study and the last 2 weeks of each phase were analysed. Compared to baseline, both BDP and NDS caused a significant improvement in PEF am (P less than 0.05), PEF pm (P less than 0.05) and the 'amplitude % mean' (P less than 0.001). Both drugs gave a highly significant improvement in all symptom scores. There was no significant difference between BDP and NDS for PEF am, PEF pm, amplitude % mean, cough and daytime asthma score. However, beta-2-agonist inhaler use and scores for nocturnal asthma and morning tightness were all significantly better in the BDP phase, and may have contributed to its better overall subjective performance. Thus, both NDS and BDP resulted in a significant improvement in asthma control in the subjects studied, and both drugs caused a similar improvement in PEF.

Carcinoma of the bronchus in tobacco farm workers. An unrecognised high risk group

A case-control study of 47 patients with bronchoscopically diagnosed carcinoma of the lung revealed that 12 were tobacco farm workers. This is significantly (p less than 0.001) greater than the number of tobacco farm workers in a healthy control group (1 out of 46). All of the tobacco farm workers smoked and 11 had smoked more than 10 pack-years of cigarettes. All of the tobacco farm workers admitted to smoking unprocessed tobacco, as did 28 of the other 35 carcinoma patients, but none of the control group. It was not possible to quantify the effect of working with tobacco or the effect of other atmosphere pollutants on a tobacco farm as possible risk factors for developing carcinoma, but this risk is unlikely to be significant compared to that from cigarette smoking.

Pneumocystis carinii pneumonia in patients with AIDS in Central Africa

Over a period of 11 months, 37 patients infected with the Human Immunodeficiency Virus (HIV) presenting with symptoms of bronchopulmonary disease were investigated. Patients presented with cough, weight loss, fever and dyspnoea. Investigations included fibreoptic bronchoscopy with bronchoalveolar lavage and transbronchial biopsy. In eight patients (22%) Pneumocystis carinii was found. Pulmonary infiltrates were found on chest radiographs of six patients, while in the remaining two patients chest radiographs showed clear lung fields. P. carinii was found in two patients with pulmonary Kaposi's sarcoma. Infection with P. carinii often occurred with other pathogens: Streptococcus pneumoniae was found in four patients, Staphylococcus aureus in two and tuberculosis in two. P. carinii pneumonia does occur in patients with HIV infection in Africa and the diagnosis is relatively simple to make provided that transbronchial biopsy and bronchoalveolar lavage are carried out through a fibreoptic bronchoscope and specimens examined after appropriate staining. However, the prevalence of P. carinii in patients with HIV infection in Africa appears to be lower than that found in patients with HIV infection in Europe and North America.

Effects of two pulmonary tuberculosis drug treatments and acetylator status on liver function in a Zimbabwean population

In Zimbabwe patients with pulmonary tuberculosis who are acid-fast bacilli (AFB) negative in the sputum are treated in the two month intensive phase with isoniazid, thiacetazone pyrazinamide and streptomycin (regimen A). Sputum positive patients receive regimen A plus rifampicin (regimen B). Both groups continue treatment with isoniazid and thiacetazone. 21 patients on regimen A and 19 on regimen B had clinical assessment and liver function tests performed at weeks 0, 2, 4, 8, and 12 weeks of treatment (during and four weeks after, the intensive phase of 8 weeks). Acetylator status was also assessed, no significant difference was found between patients on regimen A or B (41 per cent and 45 per cent fast acetylators respectively). Liver function tests results (alanine aminotransferase and alkaline phosphatase) showed a persisting rise during the intensive phase on both regimens, and further rise after four weeks in the continuation phase, this further rise reaching statistical significance in regimen B. These results are unexpected when compared to other studies but the regimens under investigation are not used elsewhere. The significant rise after stopping intensive therapy in regimen B suggests some protective effect of rifampicin against the hepatotoxicity of the regimen, possibly the isoniazid/thiacetazone component. Acetylator status did not influence the degree of hepatotoxicity.

Combination of a thiazide, a vasodilator and reserpine compared with methyldopa plus hydrochlorothiazide in the treatment of hypertension in Zimbabwe

Brinerdin (Sandoz), a combination of a diuretic (clopamide 5 mg), a vasodilator (dihydro-ergocristine 0.5 mg) and reserpine (0.1 mg) (CDR) was compared with methyldopa (MD) plus hydrochlorothiazide (HCT) for antihypertensive effect, adverse reactions, compliance and patient preference in an open cross-over trial. Eighteen patients completed both arms of the trial and 5 patients who completed the CDR arm were withdrawn while on the MD arm because of adverse effects in 4 and poor control in 1. On HCT 50 mg daily the mean baseline systolic blood pressure was 163.9 +/- 16.3 mmHg and the diastolic blood pressure was 105.9 +/- 6.7 mmHg. On CDR these were reduced to systolic blood pressure 140.3 +/- 15.1 mmHg and diastolic blood pressure 87.8 +/- 9.3 mmHg. On MD + HCT the systolic blood pressure was reduced to 138.5 +/- 16.9 mmHg and the diastolic blood pressure to 88.9 +/- 10.3 mmHg. The differences between the two treatment periods in systolic blood pressure (1.8 mmHg; 95% confidence interval (CI) - 4.1 + 7.7 mmHg) and diastolic blood pressure (1.1 mmHg; 95% CI - 4.6 + 2.4 mmHg) were not significant with P values of 0.6 and 0.7 respectively. Compliance was 98.2% for CDR and 94.7% for MD + HCT (P = 0.02). Unusual sleepiness occurred more frequently in the MD arm (P less than 0.01). Thirteen patients chose to continue on CDR, 2 on MD + HCT and 3 had no preference (P = 0.005). CDR is similar in antihypertensive effect to MD + HCT but is better tolerated with fewer withdrawals, fewer adverse effects, better compliance and has more patients electing to continue taking it.

Therapeutic review: antibiotic prophylaxis for bacterial endocarditis

A recent survey of antibiotic prophylaxis found that local practice often differed from that recommended by authoritative bodies such as the British Society for Antimicrobial Chemotherapy (BSAC) and the American Heart Association (AHA). Practitioners found the subject confusing and requested guidance. For these reasons we present current recommendations. Unfortunately all recommendations are based on animal studies and an understanding of the pathogenesis of bacterial endocarditis in humans. There are no controlled trials in humans on which to base guidelines, so rigidity is inappropriate. It is also important to realise that optimal prophylaxis will not eliminate bacterial endocarditis. In developed countries it has been estimated that only 10% of cases of endocarditis are theoretically preventable.

Pulmonary diseases in patients infected with the human immunodeficiency virus in Zimbabwe, Central Africa

During the 11 month period up to 30 September 1987, 37 patients (26 male, 11 female, mean age 27 years) with respiratory symptoms who were human immunodeficiency virus (HIV) positive, were studied prospectively on 40 occasions to determine the cause of any pulmonary complications. HIV was heterosexually transmitted. Predominant symptoms were cough (89%), fever (89%), weight loss (83%), and dyspnoea (60%). Transnasal fibre-optic bronchoscopy (with bronchoalveolar lavage, bronchial brushings and transbronchial lung biopsies) was performed on 35 patients, twice on 3 patients. 'Tru-cut' lung biopsies were obtained from 2 patients who died before bronchoscopy. Pulmonary tuberculosis was the commonest disease, being found in one-third of the patients (12 of 37). Mycobacterium tuberculosis was cultured from 4; the remainder of the plates were contaminated. Pneumocystis carinii was present in 8 patients: as the sole pathogen in 3, with Streptococcus pneumoniae in 4, Staphylococcus aureus in 2, and one also had tuberculous lymphadenitis. Endobronchial Kaposi's sarcoma was seen in 6 of 7 patients with skin nodules. Bacterial pathogens isolated included Staph. aureus (5), S. pneumoniae (5), Klebsiella pneumoniae (2), Haemophilus influenzae (2), H. parainfluenzae (1) and Pseudomonas aeruginosa (1). Invading Aspergillus fumigatus was diagnosed by lung biopsy in one. No diagnosis was reached for 8 patients. It is concluded that in Central Africa pulmonary complications in AIDS patients are similar to those in Europe and North America but the incidence of different pathogens depends on the prevalence of pathogens in the community. M. tuberculosis is probably the commonest pathogen. This study has confirmed that P. carinii pneumonia does occur, but occurs less frequently.

Ether does not antagonize bronchoconstriction caused by acetylcholine, histamine, or phenylephrine

The effect of ether as a possible antagonist of mediator-effected bronchoconstriction was tested in eight anesthetized, paralyzed, and mechanically ventilated baboons. Ether administered intravenously had no effect on bronchoconstriction caused by acetylcholine, histamine, or phenylephrine administered by the same route, either alone or in combination with propranolol.

Sputum levels of fluconazole in humans

We measured fluconazole levels in sputum samples obtained from 11 bronchiectatic volunteers at 4 and 24 h after a single oral dose of 150 mg of fluconazole. Levels in sputum were similar to levels in plasma at both times.

Lack of effect of paracetamol on the pharmacokinetics of chloramphenicol

The effect of oral paracetamol (1 g) on the pharmacokinetics of oral chloramphenicol (500 mg) was examined in five adult male Zimbabwean patients with normal hepatic and renal function. No significant alteration of half-life, area under the concentration-time curve or peak concentration of chloramphenicol was observed. The previously reported, potentially serious interaction between chloramphenicol and paracetamol administered intravenously was not observed with the more commonly used oral preparations.

Nocardiosis: a neglected chronic lung disease in Africa?

Nocardia organisms were cultured from the sputum of 11 patients at the central hospitals in Harare, Zimbabwe, over a 12 month period. Pulmonary nocardiosis was diagnosed in one further patient on the basis of direct microscopy. Among the nine patients available for follow up, pulmonary nocardiosis was considered to be the major clinical problem in six. The patients usually presented with a chronic pulmonary infection with fever and cough without evidence of dissemination of underlying systemic disease. The chest radiograph showed consolidation in any part of the lung, and this was seen to extend slowly over several months. Prolonged diagnostic delay was a frequent problem. Haemoptysis, alcohol abuse, and empirical treatment for tuberculosis commonly featured in the history. Treatment with sulphonamides was generally successful in those patients who complied. Nocardiosis is a treatable lung disease that may be more common in developing countries than is currently recognised.

Asthma induced by ivory dust: a new occupational cause

A case of asthma is reported that was due to ivory from the tusk of the elephant, a cause of occupational asthma unique to Africa.

Motivational interventions in community hypertension screening

To evaluate different techniques intended to motivate community residents to have their blood pressures taken, five inner-city target areas with comparable, predominantly Black, populations were selected. A sample of about 200 households in each of four areas were subjected to different motivational interventions; in one of these four areas, households were approached in a series of four sequential steps. The fifth target area served as a control. Findings establish that home visits by community members trained to take blood pressure measurements (BPMs) in the home produces much larger yields of new (previously unknown) hypertensives than more passive techniques such as invitational letters and gift offers. Prior informational letters, including letters specifying time of visit, do not affect refusals or increase the yield. More "passive" motivational techniques yield a higher proportion of previously known hypertensives than the more "active" outreach efforts.