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Biomedical subjects

D Rees

Publications and source records attributed to D Rees.

At least 19 recordsLinked to original sources
PubMed2005

Desferrioxamine mesylate for managing transfusional iron overload in people with transfusion-dependent thalassaemia.

BACKGROUND: Thalassaemia major is a genetic disease characterised by a reduced ability to produce haemoglobin. Management of the resulting anaemia is through transfusions of red blood cells. Repeated transfusions results in excessive accumulation of iron in the body (iron overload), removal of which is achieved through iron chelation therapy. Desferrioxamine is the most widely used iron chelator. Substantial data have shown the beneficial effects of desferrioxamine. However, important questions exist about whether desferrioxamine is the best schedule for iron chelation therapy. OBJECTIVES: To determine the effectiveness (dose and method of administration) of desferrioxamine in people with transfusion-dependent thalassaemia. SEARCH STRATEGY: We searched the Cochrane Haemoglobinopathies Trials Register, MEDLINE, EMBASE, ZETOC, Current Controlled Trials and bibliographies of relevant publications. We also contacted the manufacturers of desferrioxamine and other iron chelators. Date of last searches: April 2004. SELECTION CRITERIA: Randomised controlled trials comparing desferrioxamine with placebo; with another iron chelator; or comparing two schedules of desferrioxamine, in people with transfusion-dependent thalassaemia. DATA COLLECTION AND ANALYSIS: Four authors working independently, were involved in trial quality assessment and data extraction. Missing data were requested from the original investigators. MAIN RESULTS: Eight trials involving 334 people (range 20 to 144 people) were included. One trial compared desferrioxamine with placebo, five compared desferrioxamine with another iron chelator (deferiprone) and two compared different schedules of desferrioxamine. Overall, few trials measured the same outcomes.Compared to placebo, desferrioxamine significantly reduced iron overload. The number of deaths at 12 years follow up and evidence of reduced end-organ damage was less for desferrioxamine than placebo. When desferrioxamine was compared to deferiprone or a different desferrioxamine schedule there were no statistically significant differences in measures of iron overload. Compliance was recorded by two trials. Compliance was less for desferrioxamine than deferiprone in one trial and of no difference in comparison with desferrioxamine and deferiprone combined with a second trial. Adverse events were recorded in trials comparing desferrioxamine with other iron chelators. There was evidence of adverse events in all treatment groups. In one trial, adverse events were significantly less likely with desferrioxamine than deferiprone, relative risk 0.45 (95% confidence interval 0.24 to 0.84). Assessment of the methodological quality of included trials was not possible, given the general absence of these data in the trials. AUTHORS' CONCLUSIONS: We found no reason to change current treatment recommendations. However, considerable uncertainty continues to exist about the optimal schedule for desferrioxamine in people with transfusion-dependent thalassaemia.

Chelation Therapy↗
PubMed2005

Expression of alpha5beta1 integrin and fibronectin during early pregnancy in pigs.

The implantation in pig is superficial and non-invasive, involving phases of apposition, adhesion and attachment of conceptuses to endometrial surface epithelium. The role of integrins and ECM proteins is suggested. In the study, the expression of beta5beta1 integrin and FN on conceptus trophectoderm and endometrium during implantation and early pregnancy was investigated. The immunohistochemical localization of alpha5beta1 integrin and FN was performed on formalin-fixed, paraffin-embedded tissue sections using the ABC method. The results indicate that both conceptus and uterus expressed alpha5beta1 integrin and FN during early porcine pregnancy. The most intensive staining for alpha5beta1 integrin and FN was found in conceptus trophectoderm and endometrial surface epithelium in all investigated periods. During placentation the immunohistochemical staining for both alpha5beta1 integrin and FN was increased in trophectoderm and all endometrial structures. Since placenta in pigs is non-invasive, it can be suggested that both alpha5beta1 integrin and FN participate in molecular events leading to successful implantation and placentation in species with true epitheliochorial placenta.

Animals↗
PubMed2005

Asbestos in the non-mining industry on the Witwatersrand, South Africa.

BACKGROUND AND INTRODUCTION: For many decades, and until fairly recently, asbestos was commonly found in most sectors of South African industry. Consequently there is a large but indeterminate pool of formerly exposed workers, some of whom will present to medical practitioners for evaluation of possible asbestosis, the pneumoconiosis caused by the fibre. Fundamental to the diagnosis of asbestosis is a history of asbestos exposure sufficient to cause the disease. Attending practitioners need to be aware of the common asbestosis-inducing industries and jobs and the duration of exposure reported by patients if we are to obtain and interpret their exposures. This paper describes asbestos exposure in 141 cases of asbestosis. METHODS: Cases were identified from patient records at the Occupational Medicine Clinic of the National Institute for Occupational Health (NIOH, formerly NCOH), for the years 1980-2000. Patients were only included in the series if they had no asbestos exposure in mining, if they had been certified with asbestosis by a compensation panel, and if on re-reading of the chest radiograph a radiologist reported irregular opacities (profusion 1/0 or greater on the International Labour Organisation (ILO) scale). Asbestos exposure was taken from the patient's records. RESULTS: Only one patient was exposed in an industry where asbestos was incidental to the enterprise's operation, while 54% of cases arose from exposure in primary asbestos industries, i.e. companies selling, distributing, refining, milling or using raw asbestos to manufacture products. The mean reported duration of exposure was 17.5 years. Surprisingly, 21 cases (15%) reported less than 5 years' exposure. Unexpectedly, 7 cases had a latency period from first exposure to diagnosis of less than 6 years. CONCLUSION: The data presented should assist practitioners in the purposeful exploration of asbestos exposure and in interpretation of its significance with regard to asbestosis.

Adult↗
PubMed2004

Pulmonary function abnormalities in children with sickle cell disease.

BACKGROUND: Adults with sickle cell disease (SCD) have restrictive lung function abnormalities which are thought to result from repeated lung damage caused by episodes of pulmonary vaso-occlusion; such episodes start in childhood. A study was therefore undertaken to determine whether children with SCD have restrictive lung function abnormalities and whether the severity of such abnormalities increases with age. METHODS: Sixty four children with SCD aged 5-16 years and 64 ethnic matched controls were recruited. Weight and sitting and standing height were measured, and lung function was assessed by measurement of lung volumes and forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) before and after bronchodilator. RESULTS: Compared with the control subjects, the children with SCD had lower mean (SD) sitting height (69 (6.3) cm v 73 (7.7) cm; p=0.004), sitting:standing height ratio (0.50 (0.02) v 0.51 (0.01); p<0.0001), weight (33 (10.9) kg v 41 (14.9) kg; p=0.001), functional residual capacity measured by a helium gas dilution technique (1.2 (0.3) l v 1.3 (0.4) l; p=0.04), FEV1 (1.5 (0.5) l v 1.9 (0.7) l; p=0.0008), FVC (1.7 (0.6) l v 2.1 (0.8) l; p=0.001), and PEF (3.9 (1.3) l/s v 4.8 (1.5) l/s; p=0.0004). The effect of age on lung function differed significantly between the children with SCD and the controls for total lung capacity and vital capacity measured by plethysmography and functional residual capacity measured by helium gas dilution. CONCLUSION: Lung function differs significantly in children with SCD compared with ethnic matched controls of a similar age. Our results suggest that restrictive abnormalities may become more prominent with increasing age.

Adolescent↗
PubMed2003

Epstein-Barr virus-related post-transplant lymphoproliferative disorder with t(9;14)(p11-12;q32).

The immunoglobulin heavy chain gene locus on 14q32 is known to be involved in translocations that are associated with B-lymphoproliferative disorders, typically Burkitt lymphoma and B-cell acute lymphoblastic leukemia. Several cytogenetic abnormalities have been described in post-transplant lymphoproliferatve disease (PTLD), some of which include this locus. To our knowledge, we report the first case of translocation t(9;14)(p11-12;q32) in a PTLD that developed after orthoptic liver transplantation.

Biliary Atresia↗
PubMed2002

Tibial cyst formation after anterior cruciate ligament reconstruction using a new bioabsorbable screw.

We report a case of tibial cyst formation twelve months after anterior cruciate ligament reconstruction using hamstring graft. A composite bioabsorbable interference screw made of 'beta tricalcium phosphate and poly L-lactide' fixed the graft distally. The patient presented with acute symptoms of pain and swelling over the proximal tibia. Curettage of the cyst resulted in complete recovery within 3 months.

Absorbable Implants↗
PubMed2001

Assessment of Australian Trichogramma species (Hymenoptera: Trichogrammatidae) as control agents of stored product moths.

Trichogramma species (T. brassicae, T. pretiosum and T. carverae) were assessed for their suitability as bio-control agents against Ephestia cautella and E. kuehniella which are important pests in food manufacturing and processing facilities in Australia. Parameters examined were longevity, fecundity on eggs of E. kuehniella, walking speed of adult wasps, reaction to moth scales, and host acceptance and host suitability of eggs of E. cautella and E. kuehniella. T. pretiosum and T. carverae performed better than T. brassicae in all traits examined apart from fecundity. T. pretiosum and T. carverae differ mainly in higher fecundity and host acceptance in T. pretiosum, and a better host-finding ability (walking speed, reaction to moth scales) in T. carverae. The suitability of the Trichogramma species for use as control agents is discussed with respect to these results.

Journal Article↗
PubMed2001

Occupational asthma as identified by the Surveillance of Work-related and Occupational Respiratory Diseases programme in South Africa.

BACKGROUND: The nationwide Surveillance of Work-related and Occupational Respiratory Diseases in South Africa, SORDSA, was established in 1996 to provide systematic information on occupational respiratory diseases. OBJECTIVE: SORDSA's objectives are to monitor the nature, extent and distribution of occupational respiratory diseases, and to increase awareness of their diagnosis and prevention. This paper describes the programme and results obtained for occupational asthma in the first 2 years, ending in October 1998. METHODS: SORDSA identifies newly diagnosed cases of occupational respiratory disease through voluntary reporting by pulmonologists, occupational medicine doctors and occupational health nurses. Initially, recruitment of the above health care providers was done through the membership infrastructure of their respective professional societies. Booklets with prescribed monthly reporting forms were distributed annually to all reporting members and a core of reporting providers was established through a proactive method of data collection. Information dissemination and reporting feedback takes place through quarterly newsletters and issue-specific brochures on certain hazardous agents. RESULTS: Over the initial 2-year period, 3285 cases of occupational respiratory disease were reported to SORDSA by 203 doctors and 97 occupational health nurses. After pneumoconiosis and associated respiratory conditions, occupational asthma was the second most commonly reported disease with 225 cases (6.9%). The average annual incidence for occupational asthma in South Africa was 13.1 per million employed people, with the highest incidence reported from the Western Cape province (37.6 per million). Latex was the most frequently reported agent for occupational asthma, followed by isocyanates and platinum salts. Low molecular weight agents accounted for 59.6% of the cases of occupational asthma. CONCLUSION: The results from this initial phase show that despite some limitations, SORDSA has the potential to obtain useful data on the industries, agents and occupations causing occupational asthma in South Africa.

Asthma↗
PubMed2001

Sequence analysis of the rat phenylalanine hydroxylase gene promoter.

We have characterized the 5'-end (3218 bp) of the rat phenylalanine hydroxylase (PAH) gene. Within this PAH promoter sequence, we have identified a number of putative regulatory sites analogous to those present in the human and murine PAH promoters. In particular, potential HNF 1 binding sites and a CRE have been identified. These sequences respectively bind HNF1 and CREB transcription factors present in rat nuclear extracts and may be significant in the tissue-specific and hormonal control of PAH expression.

5' Flanking Region↗
PubMed2001

Occupational respiratory diseases in South Africa--results from SORDSA, 1997-1999.

OBJECTIVES: To describe the nature and extent of work-related respiratory diseases reported to the national Surveillance of Work-related and Occupational Respiratory Diseases in South Africa (SORDSA) reporting scheme. The causative agents and industrial categories in which they occurred are also characterised. DESIGN: Voluntary monthly reporting of newly diagnosed cases by pulmonologists, occupational medicine practitioners and occupational health nurses. SETTING: Medical and occupational health referral centres in the nine provinces of South Africa. SUBJECTS: Cases were workers from non-mining industries or ex-miners, suffering from a newly diagnosed occupational respiratory disease, reported to SORDSA between October 1996 and December 1999. OUTCOME MEASURES: Frequencies of reported occupational respiratory disease by year, reporting source, province and sex. Frequencies of short- and long-latency diseases by industry and causative agent. RESULTS: There was incomplete reporting coverage of the nine provinces in the first 3 years. Reporting was most comprehensive from Gauteng, KwaZulu-Natal and the Western Cape. Diseases with long latency periods made up 76.2% of the cases. Pneumoconiosis, even in non-mining industries, was the most frequently reported disease, followed by inhalation accidents. Occupational asthma was the fourth most reported disease. Apart from the prominence of pneumoconiosis, the results obtained by SORDSA are similar to those from a British occupational lung disease surveillance scheme. This study showed that newly diagnosed cases of occupational lung disease occurred in many industries and were caused by a variety of agents. CONCLUSION: SORDSA has contributed insight into the nature, extent and distribution of occupational respiratory diseases in South Africa. It has also highlighted important causes of occupational respiratory diseases in South Africa, as well as hazardous industries. The data indicate that South Africa has a widespread occupational lung disease problem, and provide a platform for targeted prevention strategies.

Accidents, Occupational↗
PubMed2001

Occurrence and causes of occupational asthma in South Africa--results from SORDSA's Occupational Asthma Registry, 1997-1999.

OBJECTIVE: To present results for the first 3 years of the occupational asthma registry of the Surveillance of Work-related and Occupational Respiratory Diseases in South Africa (SORDSA) programme, ending December 1999. DESIGN: Surveillance was accomplished by collecting voluntary reports of occupational asthma cases from pulmonologists, occupational medicine practitioners and occupational health nurses. SETTING: Medical and occupational health referral centres in the nine provinces of South Africa. SUBJECTS: Patients diagnosed with new-onset occupational asthma with latency or irritant-induced asthma, reported to SORDSA during 1997-1999. OUTCOME MEASURES: Frequencies of cases, causative agents, industries causing exposure and diagnostic methods. Average annual incidence rates by province and by occupation. RESULTS: During this period 324 cases of occupational asthma were reported. The average annual incidence rate of occupational asthma was estimated in the three best-reporting provinces, namely Gauteng, KwaZulu-Natal and the Western Cape, as 17.5 per million employed people annually. This rate was highest in the Western Cape (25.1 per million). Semi-skilled operators had the highest incidence rate of 68.7 per million annually in the three provinces. Isocyanates and latex were the most common agents. Low molecular weight causative agents predominated (68.8%) over high molecular weight agents. Health care was the most frequently reported workplace for occupational asthma (OA) development. Serial peak flow testing was the method most often used for diagnosis. One-fifth of the cases were still occupationally exposed to the causative agent at time of diagnosis. CONCLUSION: Despite underreporting, SORDSA's estimate of the occupational asthma incidence rate was similar to that of the UK. SORDSA has also demonstrated that surveillance programmes in a developing country can provide useful information on which to base prevention activities.

Asthma↗
PubMed2001

Asbestos lung fibre concentrations in South African chrysotile mine workers.

Mesothelioma has not been found in South African chrysotile miners and millers despite decades of producing about 100000 tons of the mineral per year. One possible explanation for the scarcity or absence of the cancer may be a relative lack of contaminating fibrous tremolite, an amphibole that variably occurs with chrysotile ores. The fibre content in the lungs of nine former chrysotile mine workers was ascertained by transmission electron microscopy. Despite fairly long service in most cases (median 9.5 yr; range 32-4 yr) the concentrations of chrysotile fibres were relatively low: only two cases exceeded 1.14 million fibres/g dried lung. Tremolite fibre levels were even lower: less than 1 million fibres/g dried lung in all but one case. Tremolite fibre concentrations exceeded those of chrysotile in only two cases. These results support the contention that South African chrysotile is not heavily contaminated by tremolite.

Adult↗
PubMed2000

Risk of mesothelioma from exposure to crocidolite asbestos: a 1995 update of a South African mortality study.

OBJECTIVE: To find the risk of developing mesothelioma in a cohort born in 1916-36 in Prieska, Northern Cape Province, South Africa. METHODS: A birth cohort mortality study was carried out in a small town in the Northern Cape Province, South Africa, with a history of crocidolite asbestos mining and milling. The cohort comprised all white births registered in the magisterial district of Prieska from 1916 to 1936, inclusive (2390). Causes of death due to mesothelioma and other cancers as recorded on medical certificates of cause of death were investigated. Person-years analysis was used to calculate mortalities due to mesothelioma, other respiratory cancers, and other non-respiratory cancers. Proportional cancer mortalities were also calculated for mesothelioma and other specific neoplasms. RESULTS: The follow up rate for the cohort was 74.3% in 1995, and 683 traced members (38.6%) had died. Cause of death was unknown for 6.4% of deaths. There were 118 cases of cancer, 28 of them from mesothelioma, giving a cause specific mortality for mesothelioma of 277 (170-384) per 10(6) person-years. The rates for men and women were 366 and 172 per 10(6) person-years, respectively. The mortality for lung cancer (29 deaths) was 287 (135-436) per 10(6) person-years, and that for other non-respiratory cancers (60 deaths) was 593 (442-745). Two cases of laryngeal and four of colon cancer were observed. All cancer mortality, mesothelioma, and lung cancer proportional cancer mortality ratios were increased. CONCLUSION: The mortality for mesothelioma in men was twice that in women, probably because men were more likely to have had both occupational and environmental exposure to asbestos. Nevertheless, the mortality in women was still high and is probably indicative of the environmental exposure as white women were rarely employed in the asbestos industry in the Prieska area. Due to the long latency from first exposure to diagnosis of the neoplasm, the cause specific mortality in this cohort could be expected to increase rapidly over the next 10 years.

Adolescent↗
PubMed2000

Pseudoaneurysm of the medial inferior genicular artery following anterior cruciate ligament reconstruction.

Pseudoaneurysm is a rare complication of surgery or trauma around the knee. A 30-year-old man presented 10 days following anterior cruciate ligament repair with a 2 cm pulsatile swelling on the medial side of the knee. Angiography demonstrated a pseudoaneurysm of the medial inferior genicular artery. Surgical exploration and ligation of the feeding vessel to the aneurysm was performed and the patient made a full recovery. Vascular injury must be suspected in patients presenting with a haemarthrosis or pulsatile swelling following surgery on the knee.

Adult↗