Electrocardiographic monitoring in severe falciparum malaria

Electrocardiographic monitoring over 24 h was performed with 53 patients with severe Plasmodium falciparum malaria (11 adults and 42 children) to assess the frequency of unrecognized cardiac arrhythmias. Nine patients (17%) died, 5 during the monitoring period and 4 afterwards. Pauses lasting 2-3 s were observed in 3 children, a single couplet in one, and a further child experienced frequent supraventricular ectopic beats which had not been detected clinically. In none of the patients who died could death be attributed to cardiac arrhythmia. Furthermore, no abnormality was detected which could have resulted from the often large doses of quinine, chloroquine or the artemisinin derivatives used for treatment. These results suggest that the heart is remarkably resilient even in the face of heavy parasite sequestration and other vital organ dysfunction, and that deaths from cardiac arrhythmias in severe malaria are rare. The need for routine cardiac monitoring of patients with severe and complicated P. falciparum malaria is questionable.

Registration of non-melanoma skin cancers in Scotland--how accurate are site and morphology codes?

Although under-reporting of non-melanoma skin cancers to cancer registries is widely acknowledged, less is known about the accuracy of information held about registered cases. In 1993, the accuracy of a random sample of cancer registrations in Scotland attributed to the year 1990 was assessed by reference to relevant medical records. The sample contained 290 registrations of non-melanoma skin cancers, 251 (90%) of which had records available for scrutiny. Here we report the results of a detailed analysis of the accuracy of site and morphology coding of non-melanoma skin cancers. Following reabstraction of details from available medical records, only three cases (1.2%) did not retain the same first three digit ICD-9 site code (173.--), although a further three cases were judged to have been registered in error. There were 56 (21.5%) discrepancies in morphology coding, but 21 of these arose through inferences about morphology in the absence of microscopic confirmation, and most of the remainder were of a relatively minor nature. In summary, it does seem possible to collect data about non-melanoma skin cancers to a reasonably high standard of accuracy. This provides some justification to those who advocate an increased effort directed towards improving levels of completeness of case ascertainment.

Registration of lung cancer in Scotland: an assessment of data accuracy based on review of medical records

Lung cancer represents a major public health problem in Scotland. Cancer registration data permit the approximate incidence of this disease to be measured directly and the projected incidence to be modelled. Thus, in addition to epidemiologic studies and survival analyses, cancer registration data may be used for planning and monitoring relevant health services. Since the value of the data depends on their quality, we undertook a large-scale study of the accuracy of cancer registration data in Scotland. The medical records of a random sample of cancer registrations attributed to the year 1990 were sought. The sample contained 340 registrations of lung cancer, 309 (91 percent) of which had relevant medical records available for scrutiny. Registration details were reabstracted from available records and compared with data in the registry. Results revealed 19 discrepancies in identifying items of data (surname, forename, gender, and date of birth) involving 16 (5.2 percent) patients. Most were trivial and would not disturb record linkage. Discrepancy rates were found to be: 7.8 percent in postcode of residence at the time of diagnosis, 10 percent in 'anniversary date' (excluding differences of six weeks or less), 12.5 percent in histologic verification status; 4.2 percent in ICD-9 site code (the first three digits), and 15.5 percent in four digit ICD-O morphology code (excluding 'inferred' morphology codes). This relatively high level of accuracy gives weight to routinely published incidence figures and supports the use of these data for exploratory epidemiologic studies, assessment of health care needs, and calculation of survival.

Registration of colorectal cancer in Scotland: an assessment of data accuracy based on review of medical records

Colorectal cancer accounts for a substantial burden of morbidity and mortality in the population. While the need for reliable incidence data may be self-evident, the quality of cancer registration data has rarely been assessed. In Scotland during 1993, the medical records of a random sample of cancer registrations attributed to the year 1990 were sought. The sample contained 238 registrations of colorectal cancer, 217 (91%) of which had relevant medical records available for review. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were recorded in eight cases (3.7%, 95% confidence intervals 1.2-6.2%). None would have disturbed record linkage. Discrepancy rates of 3.7% (1.2-6.3%) in postcode of residence at the time of diagnosis (excluding differences arising through boundary changes), 8.3% (4.6-12.0%) in 'anniversary date' (excluding differences of 30 days or less), 2.8% (0.6-5.0%) in histological verification status and 13.5% (8.9-18.1%) in morphology code (excluding 'inferred' morphology codes) were recorded. Twelve cases (5.5%, 2.5-8.6%) were deemed not to warrant site codes for cancer of the colon (ICD-9 153) or rectum (ICD-9 154). In many respects, therefore, the data held about registrations of colorectal cancer in Scotland appear to show a high level of accuracy. Completeness of case ascertainment has still to be formally assessed.

Improving the quality of cancer registration data

Cancer registration is an essential element of any cancer control strategy. Data quality is, however, of paramount importance. This paper sets out some of the ways in which the quality of cancer registration data might be improved. In particular, the potential contribution of clinicians and pathologists is highlighted.

Effect of glutathione depletion and oxidative stress on the in vitro cytotoxicity of velnacrine maleate

Velnacrine maleate (Mentane) is an aminoacridine drug developed for the treatment of Alzheimer's disease. Although velnacrine maleate has not been observed to cause prominent cytotoxicity in in vitro hepatocyte cultures, this drug was associated with elevated serum levels of hepatic enzymes in clinical trials. The purpose of the present study was to manipulate cultures of rat hepatocytes in an attempt to elicit a cytotoxic response from this drug and to better understand the in vitro mechanisms of action. Cytotoxicity was evaluated by measuring lactate dehydrogenase (LDH) leakage, neutral red (NR) uptake, and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction. Preliminary studies with fluorescent probes did not indicate a role for calcium influx or the formation of reactive oxygen species in the cytotoxicity of velnacrine maleate. However, depletion of cellular glutathione (GSH) by diamide (DA) pretreatment resulted in a cytotoxic response at concentrations of velnacrine maleate (1 and 10 micrograms/ml) which were approximately 25-fold lower than those in the absence of DA. Similarly, pretreatment with velnacrine maleate enhanced the cytotoxicity of DA. Pre-exposure of cells to a mixture of DA and t-butyl hydroperoxide (t-BHP) at non-toxic concentrations resulted in significant cytotoxicity of the hepatocyte cultures by velnacrine maleate. Results from these studies indicate that oxidative stress and GSH depletion may enhance Alzheimer patients' susceptibility to the hepatotoxic potential of aminoacridine drugs.

How accurate are Scottish cancer registration data?

In order to assess the accuracy of Scottish cancer registration data, a random sample of 2,200 registrations, attributed to the year 1990, was generated. Relevant medical records were available for review in 2,021 (92%) cases. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were found in 3.5% of cases. Most were trivial and would not disturb record linkage. Discrepancy rates of 7.1% in post code of residence at the time of diagnosis (excluding differences arising through boundary changes), 11.0% in anniversary date (excluding differences of 6 weeks or less), 7.7% in histological verification status, 5.4% in ICD-9 site codes (the first three digits) and 14.5% in ICD-O morphology codes (excluding 'inferred' morphology codes) were recorded. Overall, serious discrepancies were judged to have occurred in 2.8% of cases. In many respects, therefore, Scottish cancer registration data show a high level of accuracy that compares favourably to the reported accuracy of the few other cancer registries undertaking such analyses.

Lactic acidosis and hypoglycaemia in children with severe malaria: pathophysiological and prognostic significance

Serial clinical and metabolic changes were monitored in 115 Gambian children (1.5-12 years old) with severe malaria. Fifty-three children (46%) had cerebral malaria (coma score < or = 2) and 21 (18%) died. Admission geometric mean venous blood lactate concentrations were almost twice as high in fatal cases as in survivors (7.1 mmol/L vs. 3.6 mmol/L; P < 0.001) and were correlated with levels of tumour necrosis factor (r = 0.42, n = 79; P < 0.0001) and interleukin 1-alpha (r = 0.6, n = 34; P < 0.0001). Admission blood venous glucose concentrations were lower in fatal cases than survivors (3.2 mmol/L, vs. 5.8 mmol/L; P < 0.0001). Treatment with quinine was associated with significantly more episodes of post-admission hypoglycaemia when compared with artemether or chloroquine. After treatment, lactate concentrations fell rapidly in survivors but fell only slightly, or rose, in fatal cases. Plasma cytokine levels fluctuated widely after admission. Sustained hyperlactataemia (raised lactate concentrations, 4 h after admission) proved to be the best overall prognostic indicator of outcome in this series. Lactic acidosis is an important cause of death in severe malaria.

Initial effects of the grounding of the tanker Braer on health in Shetland. The Shetland Health Study Group

OBJECTIVE

To determine if the oil spillage from the tanker Braer had any immediate health effects on the exposed resident population.

DESIGN

Cohort study with a comparison against controls, exposure status being assigned on the basis of geographical location.

SETTING

Rural Shetland.

SUBJECTS

All those resident on or after 5 January 1993 (day 0) within 4.5 km of the site of tanker's grounding. Controls matched for sex and age were drawn from a general practice list 95 km distant.

OUTCOME MEASURES

Demographic details; smoking and alcohol consumption; perception of health and reported presence or absence of specific symptoms; peak expiratory flow; results of haematology, liver and renal function tests, and blood and urine toxicology.

RESULTS

Of subjects contacted, 420 (66%) exposed people and 92 (68%) controls were studied; 56 non-attenders were surveyed. Principal health effects arose on days 1 and 2 and were headache, throat irritation, and itchy eyes. No significant differences between those exposed and controls were found for any of the biological markers. Toxicological studies did not show any exposures that are known to affect human health.

CONCLUSIONS

The study confirmed the anecdotal reports of certain acute symptoms. No evidence of pulmonary, haematological, renal, or hepatic damage was detected at the population level. Toxicological samples from exposed people did not find levels known to affect human health. Further studies are required to ascertain whether there have been any long term effects on the population.

The epidemiology of Haemophilus influenzae invasive disease in Scotland prior to immunisation

Immunisation against Haemophilus influenzae b (Hib) was added to the UK childhood vaccination schedule on 1 October 1992. Based on reports of laboratory isolations from blood and/or CSF, the epidemiology of Haemophilus influenzae invasive disease in Scotland during the last full year before immunisation (1991) is reviewed. In children aged under five years the estimated incidence of infection (25.5 per 100,000) is higher than that previously reported from Scotland, but lower than estimates from Glasgow and other UK studies. However, the age-sex and seasonal distribution is consistent with previous surveys. As in England and Wales, there appears to be regional variation in incidence within Scotland, although this may simply reflect differences in the completeness of laboratory reporting. In addition to 113 laboratory reports of H. influenzae invasive infection, a retrospective search of hospital discharge data and death registrations identified a further 51 and two cases respectively, some of whom may be genuine. In spite of reservations about hospital discharge data, this raises the possibility that there may be an element of under-reporting by laboratories. With the advent of record linkage of hospital discharge data, it would be prudent to monitor the impact of the Hib vaccine programme using this data source in addition to laboratory reports and death registrations.

Surveillance of measles in Scotland 1983-1991; a comparison of statutory notification and laboratory reporting

The epidemiology of measles in Scotland for the period 1983-1991, based on statutory notification and laboratory reporting, is described. There were 34,823 notifications compared to only 690 laboratory reports. This suggests that for less than 1 in 50 notifications of measles was the clinical diagnosis confirmed by laboratory testing. Both sets of data show a declining incidence of measles (in keeping with rising rates of immunisation) but a statistically significant shift in the age distribution of cases towards the over 15 years age group. There were differences, however, between the two sets of data in the sex ratio within various age groups. In particular, among notified cases, there was a highly significant but unexplained preponderance of males in the over 15 years age group (59.7% vs. 40.3%, P < 0.001). Discrepancies between the two sets of data were also evident from comparisons among Health Boards. Possible sources of bias are suggested for each set of data. The relevance of this surveillance to the current debate about the need for a two stage Measles/Mumps/Rubella (MMR) immunisation policy is briefly discussed. In order that this debate be reliably informed, it is highly desirable that the clinical diagnosis in each case of apparent vaccine failure is confirmed by laboratory testing.

Comparison of artemether and chloroquine for severe malaria in Gambian children

Artemether is an oil-soluble methyl ether of artemesinin (qinghaosu). It has been studied extensively in China, where it has been shown to be rapidly effective in severe falciparum malaria. Nearly all the patients studied previously were adults. We have investigated the efficacy of artemether in children with moderate or severe falciparum malaria. In the preliminary study of moderately severe malaria, 30 Gambian children were randomised in pairs to receive either intramuscular artemether (4 mg/kg loading dose followed by 2 mg/kg daily) or intramuscular chloroquine ('Nivaquine') 3.5 mg base/kg every 6 h. Both drugs were well tolerated and rapidly effective. The times to parasite clearance were significantly shorter in the artemether recipients (mean 36.7 [SD 11.3] vs 48.4 [16.8] h, p less than 0.05). 43 children with severe malaria were then randomised to receive intramuscular treatment with the same regimens of artemether (n = 21) or chloroquine (n = 22) as used in the preliminary study. 8 children (19%) died. There were no significant differences between the two groups in the clinical, haematological, biochemical, or parasitological measures of therapeutic response in survivors and there was no evidence of local or systemic toxicity. Despite similar parasite counts on admission, clearance times overall were longer in severe malaria than in moderate malaria. Artemether is a well tolerated and rapidly effective parenteral treatment for severe malaria in children, and would be especially valuable in areas with chloroquine-resistant P falciparum.

Interethnic genetic differentiation in Africa: HLA class I antigens in The Gambia

A total of 752 individuals from The Gambia, west Africa who are representative of the major ethnic groups in the capital, Banjul, were serologically typed for HLA-A, -B, and -C antigens. Although all were typically "African" in their antigenic profiles, some marked frequency differences were found between the ethnic groups. Genetic distance comparisons with several other African populations showed that, although these west African populations clustered closely together, the positions of the various ethnic groups in The Gambia were consistent with historical and linguistic evidence of their affinities with one another and with other African populations. Despite the potential confounding effects both of selection by infectious diseases and of genetic drift caused by local differences in population structure, HLA frequencies appear to be of value in measuring inter- and intraregional population affinities in sub-Saharan Africa.

Common west African HLA antigens are associated with protection from severe malaria

A large case-control study of malaria in West African children shows that a human leucocyte class I antigen (HLA-Bw53) and an HLA class II haplotype (DRB1*1302-DQB1*0501), common in West Africans but rare in other racial groups, are independently associated with protection from severe malaria. In this population they account for as great a reduction in disease incidence as the sickle-cell haemoglobin variant. These data support the hypothesis that the extraordinary polymorphism of major histocompatibility complex genes has evolved primarily through natural selection by infectious pathogens.

Intracranial pressure in childhood cerebral malaria

Lumbar punctures were performed in 40 Gambian children with acute cerebral malaria aged between 18 months and 10 years. The mean opening pressure was elevated in 32 (80%) of the children, but was not significantly different in the 14 fatal cases compared with survivors: 110 (standard deviation 71) versus 131 (58) mm of cerebrospinal fluid respectively. Cerebral perfusion pressures were also similar in the 2 groups: 64 (20) mm Hg versus 64 (11) mm Hg respectively. There was no clear clinical evidence of raised intracranial pressure, and no evidence of deterioration immediately following lumbar puncture. Nevertheless brain swelling, and consequent brain-stem compression, may contribute to a fatal outcome in cerebral malaria--particularly in those children who die from sudden respiratory arrest. A prospective evaluation of osmotic agents in childhood cerebral malaria seems to be justified.

Sequence analysis of HLA-Bw53, a common West African allele, suggests an origin by gene conversion of HLA-B35

In the West African population of the Gambia the class I antigen HLA-Bw53 is found at high frequency. We used the polymerase chain reaction to amplify cDNA from an individual homozygous for this allele and determined the nucleotide sequence of the polymorphic alpha 1 and alpha 2 domains. The HLA-Bw53 sequence is identical to HLA-B35 except for a short sequence at the 3' end of exon 2 (encoding the alpha 1 domain) which specifies a Bw4 rather than a Bw6 motif. This suggests an origin for HLA-Bw53 involving a gene conversion of HLA-B35 by an allele containing this Bw4 sequence. The alpha 2 domain shared by HLA-Bw53, -B35, and -Bw58 is particularly common in sub-Saharan Africans.