Effective graphical displays

A graph is a visual display of data to achieve an understanding of the underlying patterns and interrelationships of the data. Such visual representations of data often form the basis for inferences and decisions. However, a poorly chosen graphical form can lead to erroneous inferences. In this paper previously published graphs depicting biopharmaceutical, drug metabolism, formulation, and pharmacokinetic data are recast using alternate display methods in an attempt to better clarify the data structure. The display methods used include dot plots and trellis plots.

Resources used by general practitioners for advising travelers from New Zealand

BACKGROUND

The risks of the destination and any specific requirements for travel health advice may be obtained from a variety of resources. This study was designed to investigate the usefulness of various resources available in New Zealand for providing travel health advice and the extent to which GPs used these resources in providing travel health advice.

METHOD

Four hundred GPs (400/2830) were randomly selected from the register of the New Zealand Medical Council and sent self-administered questionnaires. Two reminders were sent.

RESULTS

Three hundred and thirty-two (332/400, 83%) GPs responded. The usefulness of various resources was reported, including Health Advice for Overseas Travellers (277/289, 96%), New Ethicals (256/278, 92%), New Zealand Public Health Report (79/164, 48%), International Travel and Health (41/144, 28%), computerized databases (6/122, 5%), journals (14/130, 11%), and other resources (44/139, 32%). Health Advice for Overseas Travellers was regarded as significantly more useful than International Travel and Health (x2 = 4,68, df = 1, p <.05). Only 23% (70/309) of respondents indicated that they always used these resources in their practice of travel medicine. Fifty percent (154/309) of respondents indicated that they usually used these resources, while 27% (83/309) of respondents indicated that they used these resources sometimes. Only 1% (2/309) of GPs did not use resources at all for their practice of travel medicine.

CONCLUSIONS

The most useful resource was Health Advice for Overseas Travellers, which outlines the New Zealand recommendations for medical practitioners providing travel health advice. It may be useful for GPs to gain access to and training in association with a greater range of specialist resources to use in conjunction with the provision of travel health advice. These might include international guidelines, journals, and access to computerized databases and the internet. With the recent introduction of a widely accessible computerized database in New Zealand, follow-up studies could be instituted to determine if GPs' use of computerized databases becomes more widespread and whether access to and use of these computerized databases influences the provision of travel health advice by GPs. Further studies are needed to examine the appropriateness of the advice provided by the various resources used by GPs in New Zealand.

Refining the mouse chromosomal location of Cdm, the major gene associated with susceptibility to cadmium-induced testicular necrosis

Cadmium (Cd++) is a widespread environmental pollutant and classifed as an IARC 'Category I' human carcinogen. Cd++ can also cause severe renal toxicity and may be involved clinically in cardiovascular disease and osteoporosis. Genetic differences in sensitivity to cadmium toxicity have been noted in humans, whereas, among inbred mouse strains, unequivocal genetic data exist. Resistance to cadmium-induced testicular damage was reported in 1973 to be associated with a single major recessive gene, named Cdm, which has now been localized to mouse chromosome (Chr) 3. Using polymorphic microsatellite markers and semiquantitative histological parameters, we have corroborated the original 1973 data concerning mendelian inheritance and have further refined the region containing the Cdm gene from more than 24 cM to 0.64 cM (estimated 40-80 genes). We phenotyped 26 recombinant inbred lines generated from C57BL/6J (B6, resistant) and DBA/2J (D2, sensitive) inbred mice, and determined that the Cdm gene maps between microsatellite markers D3Mit110 and D3Mit255. Although toxicity to numerous heavy metals is well known, virtually no molecular mechanisms have yet been uncovered either in humans or laboratory animals. Identification and characterization of the mouse Cdm gene should enhance our understanding of heavy metal toxicity by identifying and characterizing, for the first time, a major mammalian gene responsible for susceptibility to diseases caused by heavy metal toxicity.

Training, experience and interest of general practitioners in travel medicine in New Zealand

BACKGROUND

In New Zealand, general practitioners (GPs) are a major group of travel health advisers. This study was designed to investigate the prevalence of training, experience, and interest in travel medicine or related areas, interest in undertaking training in travel medicine and how training might be best delivered.

METHOD

Four hundred GPs were randomly selected from the register of the New Zealand Medical Council and sent self-administered questionnaires. Two reminders were sent.

RESULTS

Three hundred and thirty-two (83%) GPs responded and these GPs advised an average of two travelers per week. Most GPs (257/282, 91%) reported that they had no training in travel medicine/related area. Training in travel medicine/related areas was significantly associated with age group (x2=14.09, df=6, p<.05), with the proportion of GPs with training in travel medicine/related area tending to be higher in the 45-49 and 50-54 years age groups, and also with GP college membership/fellowship (x2=6.39, df=1, p<.05). Forty-one percent (121/298) of respondents stated that they had previous experience working in tropical medicine/developing country. There was a significant association between GPs having experience working in tropical medicine/developing countries and training in travel medicine (x2=14. 19, df=1, p<.001) and those who were non-New Zealand graduates (x2=7. 84, df=1, p<.01). Forty-four percent (131/300) of respondents stated that they had an interest in travel medicine. Nearly two thirds of respondents (200/309, 65%) indicated that they would be interested in undertaking various types of travel medicine training, with a short course most commonly identified (159/309). The interest for training in travel medicine was significantly associated with those GPs with an interest in travel medicine (x2=26.45, df=1, p<.001), in younger age groups (x2=41.30, df=6, p<.001), a lower mean number of years since graduation (t value=5.70, df=297, p<.001), a higher mean proportion of patients who were travelers (t value=23.15, df=303, p<. 01), and a higher mean number of travelers seen per week (t value=22. 94, df=303, p<.01). The most common postgraduate qualification amongst GPs was membership/fellowship of a GP college (85/282, 30%), which was significantly more prevalent amongst the older age groups (x2=18.18, df=8, p<.05). Membership of travel medicine was very low.

CONCLUSIONS

This cross-sectional study found that most GPs in New Zealand did not have any formal training in travel medicine, although more than two fifths of GPs indicated an interest in travel medicine and experience in tropical medicine/related area. GPs mainly wanted continuing medical education (CME) on travel medicine in the form of short and certificate level courses. As membership in GP colleges and other organizations was limited, other providers of CME should also be considered for providing more of these courses, such as universities and pharmaceutical companies. Providers of CME may target less experienced GPs and those GPs who may be seeing more travelers and use various approaches. Undergraduate and postgraduate medical curricula may also need to include more training in travel medicine.

Health advice given by general practitioners for travellers from New Zealand

AIMS

To investigate where general practitioners (GP's) in New Zealand view travel health advice best given and where they refer for this advice, the prevalence of travel health advice reported to be given, and the prevalence of written advice, including a doctor's letter.

METHOD

This was a descriptive cross-sectional study, using self-report questionnaires, sent to 400 GPs randomly selected from the register of the New Zealand Medical Council.

RESULTS

Three hundred and thirty-two GPs (83%) responded. Most GPs reported that they saw travel medicine as best practised in general practice (241/308, 78%) or in a combination of locations, usually including general practice (28/308, 9%). Most GPs (223/308, 72%) did not refer travellers for travel health advice. Health advice concerning malaria (310/310, 100%), immunisation (309/310, 100%), travellers' diarrhoea (296/305, 97%), insect avoidance (287/ 299, 96%), sexually transmitted diseases/human immunodeficiency virus (233/283, 82%), water purification (235/293, 80%) and other areas (35/75, 47%) was given. Written advice was usually given by 23% of GPs (69/302). Written advice was significantly more likely to be provided by those GPs with an interest in travel medicine (chi2=5.67, df=1, p<0.005), experience in tropical medicine/developing countries (chi2=6.69, df=1, p<0.001), a policy on travel medicine (chi2=21.4, df=1, p<0.001), a written policy on travel medicine (chi2=302.0, df=1, p<0.001), who saw a higher number of travellers per week (t=-2.51, df=296, p<0.05) and who saw a significantly higher proportion of patients who were travellers (t=-3.27, df=-295, p=0.001). Almost all GPs (303/310, 98%) reported giving their travelling patients a doctor's letter at least sometimes but only 7% (23/310) always gave travellers a doctor's letter. GPs with training in travel medicine/related area were significantly more likely to provide travellers with a doctor's letter (chi=11.61, df=3, p<0.01).

CONCLUSIONS

This study confirmed that GPs in New Zealand see travel health advice as best given in general practice. Travel health advice, as recommended by New Zealand guidelines, should continue to be given. With limited time in general practice to advise travellers, GPs should also consider giving written advice, including a doctor's letter, more often. Epidemiological and specialist support by public health units and commercial groups, continuing medical education and training in travel medicine for GPs are among the major considerations. Further studies are needed concerning the adequacy and currency of destination-specific advice for travellers.

Prevalence of dental caries and co-relation with fluorosis in low and high fluoride areas

The aim of the study was to determine the degree of caries prevalence in the permanent dentition and the accompanying fluorosis in children between 6-16 years of age in both low (0.5 ppm) and relatively high (1.2 ppm) fluoride areas. In 3605 children in a low fluoride area (Dharwad), the mean DMFT was 0.65; 77% of the children were caries free. Grade I fluorosis (using Dean's fluorosis inded) was observed in only 0.66% of the children. Among 3618 children of similar age groups, living in high fluoride areas (Gadag), 84% were caries free and the mean DMFT value was 0.39. Varying degrees of fluorosis were present in 57.07% of the children. The results of the study suggest a definite relationship between the amounts of fluoride ingested through water and caries experience observed in the population.

Chronotropic competence of the sinus node in congenital complete heart block

Electrocardiograms taken at rest of 2 children with transplacental exposure to anti-Ro antibody but 1:1 atrioventricular conduction demonstrated sinus node disease. Treadmill exercise testing of 28 patients with congenital complete heart block found 3 patients with chronotropic incompetence of the sinus node.

Safety advice for travelers from New Zealand

BACKGROUND

Accidents and injuries are important preventable causes of morbidity and mortality for travelers. This study was designed to investigate the prevalence of advice given by general practitioners (GPs) on personal safety, health and travel insurance, and finding medical assistance abroad in the event of misadventure or ill health.

METHOD

Four hundred general practitioners were randomly selected from the register of the New Zealand Medical Council and sent self-administered questionnaires. Two reminders were sent.

RESULTS

Three hundred and thirty-two (83%) GPs responded. Advice to travelers on health and travel insurance (164/273, 60%), personal safety (127/255, 50%), and finding medical assistance abroad (165/308, 54%) was given by half or just over half of GPs. Giving advice on medical assistance abroad was significantly associated with giving advice on health and travel insurance (x2 = 18.89, df = 1, p<.001) and personal safety (x2 = 25.26, df = 1, p<.001). Seeing a higher proportion of patients who were travelers was significantly associated with giving advice on health and travel insurance (t-value = -3.39, df = 267, p = .001) and personal safety abroad (t-value = -2.63, df = 249, p &lt; .01). Those GPs with previous experience in tropical medicine/developing countries were significantly more likely to advise travelers on personal safety abroad (x2 = 6.55, df = 1, p<.05) and about seeking medical assistance abroad (x2 = 4.11, df = 1, p<.05). Those GPs in older age groups (45-49 years and over) were significantly more likely to advise travelers on health and travel insurance (x2 = 16. 31, df = 8, p<.05) and personal safety abroad (x2 = 19.88, df = 8, p<.05). Those GPs with an interest in travel medicine were significantly more likely to advise travelers about seeking medical assistance abroad (x2 = 11.07, df = 1, p<.001) and health and travel insurance (x2 = 16.31, df = 8, p<.05). When advising travelers about seeking medical assistance abroad, GPs most commonly recommended contacting travel insurance companies (60/308, 19%), a specific medical service (48/308, 16%), tour company (30/308, 10%), specific doctor (29/308, 9%), New Zealand embassy (27/308, 9%), local medical service (23/307, 7%), personal contact (21/307, 7%), and other sources (12/307, 4%).

CONCLUSIONS

This cross-sectional study found that only around half of New Zealand GPs were giving advice to travelers on personal safety, health and travel insurance, and finding medical assistance abroad. Continuing education providers should reinforce the need for this advice to be given to all travelers. There was also considerable variability in what New Zealand GPs recommended to travelers about seeking medical assistance abroad, including several nonmedical sources.

Histopathological evaluation of inflammatory & hereditary demyelinating polyneuropathies

In view of therapeutic implications and problems in clinical diagnosis, this study sought to evaluate and identify histopathological features of acquired inflammatory demyelinating neuropathies and hereditary demyelinating neuropathies. Sural nerve biopsies from 41 patients of demyelinating neuropathies, diagnosed on the basis of accepted clinical criteria, were studied using routine histological staining and special stains for myelin and axons. Chronic inflammatory neuropathies differed from the acute ones in having more endoneurial connective tissue, less of subperineurial oedema and presence of axonal sprouting and occasional onion bulb formation. Acquired neuropathies differed from hereditary neuropathies in having a more localized involvement, endoneurial oedema and variable inflammatory cell infiltration, while in hereditary neuropathies Schwann cell proliferation was diffuse and relatively uniform. The frequency and degree of nerve thickening was more in hereditary neuropathy. Evidence of inflammation was not universal, both in the acute and the chronic inflammatory demyelinating neuropathies. Histopathological examination is essential as the clinical and electrophysiological features alone may not offer definitive diagnosis.

Health care costs of obesity in New Zealand

OBJECTIVE

To estimate the costs of health care that are attributable to obesity in New Zealand.

METHODS

The 1991 health care costs of non-insulin dependent diabetes, coronary heart disease, hypertension, gallstone disease, post-menopausal breast cancer and colon cancer were estimated and multiplied by the population attributable factor for obesity for each condition. The relative risk estimates were taken from the literature, the obesity prevalence from a 1990 New Zealand survey, and the costs and volumes of services were taken from a variety of sources and covered hospital (inpatient and outpatient) services, general practitioner consultations, pharmaceuticals, laboratory tests and ambulance services. Calculations were conservative and net of goods and services tax.

RESULTS

A conservative estimate of the health care costs attributable to obesity for the six conditions was NZ$135 million. This represents about 2.5% of total health care costs which is similar to analyses from other countries.

CONCLUSIONS

The health care costs of obesity as estimated are considerable. However, the total cost of overfatness to the New Zealand population is far greater than this because lesser degrees of overfatness, the health care costs of other obesity-related conditions such as arthritis, the costs to individuals of weight-loss programs and the indirect and intangible costs were not included in the analysis. A substantial and wide-ranging public health effort is needed to turn around the increasing prevalence and costs of obesity.

Malaria prophylaxis prescribed for travellers from New Zealand

AIM

To investigate advice given by general practitioners on the use of chemoprophylaxis and other preventive measures against malaria.

METHOD

Four hundred general practitioners were randomly selected from the register of the New Zealand Medical Council and sent self-administered questionnaires.

RESULTS

Three hundred and thirty two (83%) general practitioners responded. Advice concerning malaria (310/310, 100%) and insect avoidance (287/299, 96%) was commonly given. The most commonly prescribed regimes for malaria chemoprophylaxis were chloroquine (93/305, 30.5%), chloroquine plus either quinine or mefloquine as a standby (63/305, 21%), mefloquine (45/305, 15%), chloroquine/Maloprim (pyrimethamine/dapsone) (41/305, 13%), doxycycline (26/305, 8%), and chloroquine plus doxycycline (24/305, 8%). Chloroquine plus Maloprim was used significantly more by general practitioners in older age groups, ie 45 years and over (p < 0.05).

CONCLUSIONS

This cross sectional study has shown variability in the patterns of antimalarials used. Issues of concern include continued use of chloroquine alone, given widespread global resistance, and the use of Maloprim. Although Maloprim use has not been recommended since 1992, it is still being used by a substantial minority of general practitioners. This issue, which needs to be addressed nationally, is of concern given the adverse events associated with the use of Maloprim. New methods for the effective dissemination of information regarding appropriate chemoprophylaxis need to be developed.

Human Ah receptor (AHR) gene: localization to 7p15 and suggestive correlation of polymorphism with CYP1A1 inducibility

The mammalian aromatic hydrocarbon receptor (AHR) is a ubiquitous ligand-activated transcription factor. AHR ligands include 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD; dioxin), benzo[a]pyrene, and polychlorinated and polybrominated biphenyls; the endogenous ligand is not yet known. Following ligand binding, the AHR transcriptionally activates genes encoding drug-metabolizing enzymes important in both the metabolic potentiation of substrates to genotoxic reactive intermediates and ultimate carcinogens, and the detoxification of toxic or carcinogenic drugs and other environmental pollutants. AHR-mediated gene expression is also involved in many critical life processes (e.g. cell type-specific differentiation, cell division, apoptosis) by signal transduction mechanisms. Similar to mice, human populations exhibit a > 20-fold range of the CYP1A1 inducibility/AHR affinity phenotype. In the present study, we localized the human AHR gene to chromosome 7p15, using fluorescence in situ hybridization (FISH). Performing linkage analysis in a three-generation family, we show with good probability that the high CYP1A1 inducibility phenotype segregates with the 7p15 region. Sequencing 93 nt (31 amino acids) of the human AHR gene's exon 9, which is the region correlated with the mouse A375V polymorphism responsible for the major portion of high vs low CYP1A1 inducibility/AHR affinity, we found no nucleotide differences; Val-381 was present in all five individuals examined (four related and one unrelated), two of whom show "high' and three of whom show "low' CYP1A1 inducibility. These data indicate that the "high' and "low' CYP1A1 inducibility trait, in the population studied, cannot be explained by a difference among these 31 amino acids in exon 9 of the AHR gene.

Extra pelvic endometriosis and catamenial pneumothorax

Extra pelvic endometriosis is rare and its presentation is varied. A case of pulmonary and umbilical endometriosis which presented as catamenial pneumothorax is presented. Due to poor response to medical treatment, a total abdominal hysterectomy and bilateral salpingo-oophorectomy was done to relieve the patient of her recurrent symptoms.

Mortality and morbidity from malaria after stopping malaria chemoprophylaxis

Gambian children who had received malaria chemoprophylaxis for a variable period of time during their first 5 years of life were followed to determine whether they experienced a rebound in mortality or in morbidity from malaria during the period after chemoprophylaxis was stopped. The risk of dying between the ages of 5 years, when chemoprophylaxis was stopped, and 10 years was no higher among children who had received chemoprophylaxis with Maloprim (pyrimethamine plus dapsone) for some period during their first 5 years of life than among children who had received placebo (21 vs. 24 deaths) and the beneficial effect of chemoprophylaxis on mortality observed during the first 5 years of life was sustained. The incidence of clinical attacks of malaria during the year after medication was stopped was significantly higher among children who had previously received Maloprim for several years than among children who had previously received placebo. However, at the end of this year, there was no significant difference in spleen rate, parasite rate or packed cell volume between the 2 groups of children. Thus, stopping chemoprophylaxis after a period of several years increased the risk of clinical malaria but did not result in a rebound in mortality in Gambian children. However, the number of deaths recorded was small, so a modest effect on mortality cannot be excluded.

Disseminated Burkitt's lymphoma presenting as multiple cranial nerve palsies

A case of disseminated Burkitt's lymphoma with nervous system involvement in a HIV negative 35 year old lady is described. She primarily presented with multiple cranial nerve palsies. At autopsy, diffuse involvement of parenchymatous organs and lymphomatous meningitis with conspicuous sparing of gastrointestinal system was observed. In addition, there was an unusual feature of paraneoplastic demyelinating peripheral neuropathy. Incidentally, a large hydatid cyst was also seen in the left lobe in addition to the lymphomatous involvement of the liver.

Undernotification of tuberculosis in Otago: national implications

AIM

To ascertain the reliability of notification of tuberculosis in Otago; to establish a more accurate incidence rate for cases of tuberculosis in Otago.

METHODS

Official notification information 1985-93 was cross checked against other record systems.

RESULTS

In the 1985-90 period the official notifications were underestimated by 33% (28/84) and during 1991-2 by 48.5% (17/35). The crude annual incidence rates for all cases were 7.3 per 100,000 for the 1985-90 period and 9.1 per 100,000 for the 1991-3.

CONCLUSION

The average annual crude incidence rates for tuberculosis were considerably higher than the official rates. Tuberculosis remains an important clinical and public health issue. Improvements in notification locally and nationally are required if the impact of the projected increase in tuberculosis is to be minimised.

The costs of mammography screening in New Zealand: evidence from the pilot programmes

AIMS

To measure the public health service costs associated with New Zealand's pilot mammography screening programmes. To compare the early evidence on cost per woman screened and per cancer detected in those programmes to that of overseas screening programmes. To estimate the cost of introducing a national screening programme in New Zealand.

METHODS

Costs in each screening centre were obtained by a careful examination of screening budgets and public health service accounts; these were inflation adjusted using a consumers price index, and analysed in terms of equivalent annual operating costs.

RESULTS

In the first year of screening the cost per woman screened (in $1991) was $182 in Waikato and $178 in Otago/Southland. The cost per woman screened in the third year of screening (with an assumed full screening throughput of 8,000 women per annum) is estimated to fall to $106 and $113 for the Waikato and Otago/Southland programmes respectively. The cost per cancer detected in the first screening round differs between the two programmes. In the first year of screening the cost per cancer detected was $35,975 in Waikato and $21,908 in Otago/Southland. The difference was primarily attributable to a lower cancer detection rate in Waikato in that period (0.51% of women screened compared with 0.81% in Otago/Southland).

CONCLUSIONS

The initial performance of the New Zealand pilot programmes, both in terms of cost per woman screened and cost per cancer detected, falls within the range indicated from overseas experience. An established national screening programme is estimated to add between $9.3 and $9.9 million dollars (in 1991 dollar terms) to health service costs each year. These costs will be partly offset by savings resulting from the earlier detection of cancers.

Effect of corticosteroid therapy on human immunodeficiency virus-associated nephropathy

PURPOSE

Human immunodeficiency virus-associated nephropathy (HIV-AN) occurs predominantly in blacks and is characterized histologically by focal segmental glomerulosclerosis or mesangial proliferation and a lymphohistiocytic tubulointerstitial infiltrate. Patients manifest heavy proteinuria and, once azotemia occurs, progress rapidly to end-stage renal disease within 2 to 6 months. No treatment has been shown to be useful for HIV-AN. The purpose of this study was to determine the effect of corticosteroid agents on the progression of HIV-AN.

PATIENTS AND METHODS

Four consecutive HIV-infected adults with fewer than 200 CD4 cells/microL, moderate to severe renal insufficiency, proteinuria greater than 2 g per 24 hours, and HIV-AN demonstrated by renal biopsy were treated with 60 mg of prednisone daily for 2 to 6 weeks. Patients were followed with respect to serum creatinine level, 24-hour protein excretion, adverse drug reactions, and the occurrence of opportunistic infections.

RESULTS

CD4 counts ranged from 30 to 80 cells/microL before therapy with steroids. The mean (+/- SD) pretreatment serum creatine concentration was 9.1 +/- 5.7 mg/dL and decreased to 3.3 +/- 1.8 mg/dL (P < 0.05) after 2 to 6 weeks of corticosteroid therapy. Twenty-four hour protein excretion did not change (5.2 +/- 2.4 g pretreatment versus 4.6 +/- 4.1 g posttreatment). One patient was able to discontinue dialysis after 10 days. Two patients developed Mycobacterium avium-complex infections and steroid-associated psychosis. One of these patients developed a recurrence of genital herpes, and the other developed dermatomal zoster. None of the four required dialysis during a 1.5- to 5.5-month period of follow-up after cessation of steroid treatment.

CONCLUSION

In selected patients with HIV-AN, short-term treatment with corticosteroid agents improves renal function and prevents the development of end-stage renal disease during a 1.5- to 5.5-month period of observation, but may be associated with an increased risk of opportunistic infection.

Development and evaluation of a monolithic floating dosage form for furosemide

The poor bioavailability of orally dosed furosemide (60%), a weakly acidic drug, is due to the presence of a biological window comprised of the upper gastrointestinal tract. The purpose of the present study was to develop and optimize in vitro a monolithic modified-release dosage form (MMR) for furosemide with increased gastric residence time and to evaluate the in vivo performance of the dosage form. The principle of floatation was used to restrict the MMR to the stomach. A two-factor three-level full factorial experimental design was employed for formulation development. A flow-through cell was designed to evaluate in vitro dissolution parameters. Quadratic regression models indicated the polymer viscosity and polymer:drug ratio to be significant (p < 0.05) formulation factors in determining the duration of buoyancy and the release profile. Statistical optimization using response surface methodology with certain physiological constraints relating to gastric emptying time predicted an optimal MMR. In vivo evaluation of the optimized MMR in beagle dogs resulted in a significant increase (p < 0.05) in the absolute bioavailability for the MMR dosage form (42.9%) as compared to the commercially available tablet (33.4%) and enteric product (29.5%). Significant in vitro/in vivo correlations (p < 0.05) were obtained for the MMR using deconvolution analysis normalized for bioavailability. The floating dosage form was found to be a feasible approach in delivering furosemide to the upper gastrointestinal tract to maximize drug absorption.

Effect of mode of incorporation of disintegrants on the characteristics of fluid-bed wet-granulated tablets

A full factorial experimental design was employed to investigate the effects of mode of disintegrant incorporation and concentration in wet-granulated paracetamol tablets manufactured by top-spray fluid-bed. Disintegrants (croscarmellose sodium, sodium starch glycolate, or crospovidone) were incorporated either intragranularly, extragranularly, or distributed equally between the two phases. The results were analysed by a general quadratic equation and response surfaces generated. On examining the results for dissolution studies the combined mode resulted in significantly faster dissolution rates than did the extragranular mode which, in turn, was superior to the intragranular mode of inclusion. These results were reflected in the disintegration studies where the combined mode exhibited the shortest disintegration times for all the disintegrants. Tablet crushing strength was not affected by the mode of incorporation of concentration of the disintegrants. Main as well as interaction effects between the types, mode of incorporation and percent disintegrant employed were significant (P < 0.05) for disintegration time and percent release at 15 min. Croscarmellose sodium exhibited the shortest while crospovidone displayed significantly (P < 0.05) longer disintegration times. Formulations containing crospovidone did not meet official compendial (USP XXII) requirements of 80% in 30 min. In general, croscarmellose sodium and sodium starch glycolate were found to be less sensitive to the mode of incorporation than crospovidone.

Decline in meningococcal antibody levels in African children 5 years after vaccination and the lack of an effect of booster immunization

Antibodies to group A meningococcal polysaccharide were measured by hemagglutination (HA) and by ELISA in sera obtained from Gambian children before vaccination and 3 weeks, 2 years, and 5 years after vaccination with a group A + group C meningococcal capsular polysaccharide vaccine. Children were 1-4 years old at the time of vaccination. Most showed a good initial response to vaccination, including those aged 1-2 years. However, antibody titers declined progressively during follow-up, and 5 years after vaccination, antibody titers measured by both HA and ELISA had returned to prevaccination levels. This decline was not influenced significantly by a booster dose of vaccine given 2 years after initial immunization. Administration of malaria chemoprophylaxis reduced the rate at which antibody levels fell after initial immunization. Sustained protection of children against group A meningococcal disease will require the development of vaccines that are immunogenic in infants and that can induce T cell memory.

Sarcoidosis: a review of cases seen at the University Hospital, Kuala Lumpur

Fourteen cases of sarcoidosis consisting of 7 male and 7 female patients with a mean age of 42.4 years were seen at the University Hospital from 1972 to 1990. There were 10 Indians, 2 Malays, and 2 Chinese. Twelve patients had thoracic involvement. The other common disease manifestations included weight loss, arthralgia, hepatomegaly, erythema nodosum, peripheral lymphadenopathy, and hypercalcaemia. At initial presentation, the disease was in radiographic stage I, II, and III in 8, 3 and one patient respectively. The Kveim test was positive in 7 out of 9 patients. Eight patients required steroid therapy.

A set of STS assays targeting the chromosome 22 physical framework markers

The widespread use of the sequence-tagged site (STS) as a quick, efficient, and reproducible assay for comparing physical and genetic map information promises to facilitate greatly long-range goals of the mapping of the human genome. We have designed 21 STS assays for loci on human chromosome 22. These assays primarily tag the physical framework markers of the long arm of 22, but additional assays have been designed from known genes and loci in the neurofibromatosis 2 (NF2) region. The availability of these assays will make these loci available to the research community without physical transfer of materials and will serve as start points for further efforts to physically map chromosome 22 with yeast artificial chromosome clones.

Complete human NF1 cDNA sequence: two alternatively spliced mRNAs and absence of expression in a neuroblastoma line

Neurofibromatosis type 1 (NF1) is caused by mutations in a large gene on chromosome 17q11.2. Previously described partial cDNAs for this gene predicted a protein related to yeast IRA1/IRA2 and the mammalian RAS GTPase activator protein GAP. To initiate a detailed study of the role of this gene in NF1, we have characterized a set of overlapping cDNAs that represent its complete coding sequence. Our results show that two differentially expressed human NF1 mRNAs differ by a 63-bp insertion in the GAP-related domain. These mRNAs predict two 2,818- and 2,839-amino acid proteins with calculated molecular masses of approximately 317 and 319 kD. Extensive similarity to IRA proteins is evident in a 1,450-amino-acid central segment, roughly between amino acids 900 and 2,350. However, the remainder of the NF1 protein is not significantly similar to other proteins. Interestingly, the SK-N-SH human neuroblastoma line expresses no detectable NF1 mRNA, indicating that expression of NF1 is not essential for viability of this neural crest-derived tumor cell line.

Evidence for the association of unexplained pulmonary hypertension in children with the major histocompatibility complex

BACKGROUND

A link between primary pulmonary hypertension (PPH) and autoimmune disorders has been postulated. To investigate this relation, we performed immunofluorescent antinuclear antibody tests (ANA) and serological human leukocyte antigen (HLA)-A, B, C, DR, and DQ typing on two groups of Caucasian children with unexplained pulmonary hypertension (PHT) and their parents.

METHODS AND RESULTS

Group 1 consisted of 17 children with PPH including two patients with familial PPH and three patients with trivial congenital pulmonary to systemic communications. Group 2 consisted of 13 children with advanced PHT and anatomically large congenital pulmonary to systemic communications (PHT + shunt). Both groups had comparably severe pulmonary vascular disease documented by cardiac catheterization. The following statistically significant data (p less than 0.05) were obtained when the study groups were compared with those published for normal controls. Although positive ANAs and varying titers of autoantibodies were found in both groups of children and mothers (not fathers), +ANAs were only significant for the maternal groups. The PPH (group 1) children had increased frequencies of HLA-DR3, DRw52, and DQw2 and decreased DR5, whereas the group 2 (PHT + shunt) children (also their parents) had no statistically significant alterations in any of the DR or DQ alleles. The PPH mothers had decreased DQw3, an allele in linkage disequilibrium with DR5.

CONCLUSIONS

These immunogenetic data suggest that childhood PPH appears to be associated with the major histocompatibility complex alleles HLA-DR3, DRw52, and DQw2. This newly found correlation of juvenile PPH with these alleles adds this disease to the DR3+ group of autoimmune diseases. Further studies are needed to determine whether there is also an immunological or autoimmune component in some children with PHT + shunt lesions because this group lacked an HLA association.

Diagnosis of Legionnaires' disease by radioimmunoassay of Legionella antigen in pleural fluid

We describe a case of culture-proven Legionnaires' disease (serogroup 1) in which a rapid diagnosis was made by detection of Legionella antigen in pleural fluid by use of the Binax radioimmunoassay for urine.

Biopharmaceutic evaluation of furosemide as a potential candidate for a modified release peroral dosage form

An attempt was made to evaluate some of the criteria for developing a modified release peroral dosage form for furosemide which has a poor bioavailability when given in the conventional peroral dosage forms. The pathway of absorption for furosemide was studied ex vivo employing the Wilson-Wiseman test. Passive absorption was found to be the predominant mechanism of transport across the ileum of the guinea pig followed by active transport to the extent of about 17%. The in situ procedure to study the extent of absorption of furosemide from the various sites in the lumen of the gastrointestinal tract of the rat indicated the stomach to be the major site of absorption followed by the duodenum. It is hence postulated that due to the site-specificity and mechanism of absorption a peroral modified release dosage form having a longer gastric residence time could possibly increase the bioavailability of furosemide.

Pharmacokinetics and bioavailability of papaverine HCl following intravenous, peroral, rectal, vaginal, topical and buccal administration in beagle dogs

This in vivo study was designed to obtain bioavailability data and a definite pharmacokinetic profile of papaverine HCl in Beagle dogs following intravenous (IV), peroral (PO), rectal, vaginal, topical, and buccal administration of different papaverine HCl formulations. Blood samples were analyzed by high-performance liquid chromatography. The pharmacokinetic parameters were determined using either a curve fitting program (RESID) or a compartment model independent program (AUC-RPP). The plasma concentration-time profiles show that papaverine HCl pharmacokinetics is best described by an open two-compartment model. The absolute bioavailability of papaverine HCl was determined to be 57.2 per cent, 25.2 per cent, 53.2 per cent, 3.2 per cent and 7.5 per cent, respectively, following P.O., rectal, vaginal, topical and buccal administration.

TP53 gene mutations and 17p deletions in human astrocytomas

Astrocytomas, including the most malignant form, glioblastoma multiforme, are the most frequent and deadly primary tumors of the human nervous system. Recent molecular genetic analyses of astrocytomas have demonstrated frequent chromosome 17 deletions involving the telomeric region of the short arm (17p12-pter). This region contains a candidate tumor suppressor gene, TP53, which has recently been implicated in the etiology of a broad array of human cancers. To study the possible role of TP53 in astrocytoma development, 24 randomly chosen human astrocytic tumors were examined for genomic TP53 sequence aberrations using primer-directed DNA amplification in conjunction with direct sequencing. Five of the 11 grade III astrocytomas (glioblastoma multiforme), but only one of seven grade II astrocytomas (anaplastic astrocytoma) and none of either the grade I astrocytomas or oligodendrogliomas demonstrated distinct point mutations involving the TP53 gene. These data suggest that TP53 mutations may play a role in astrocytoma development and are predominantly associated with higher grade tumors.

Sustained protection against mortality and morbidity from malaria in rural Gambian children by chemoprophylaxis given by village health workers

Mortality and morbidity from malaria were measured in children for a one-year period in a rural area of The Gambia 3-4 years after the introduction of a primary health care programme into some villages in the study area. Among children resident in primary health care villages who received treatment for febrile illnesses from a village health worker resident in their village there was no reduction in overall mortality or in morbidity from malaria compared with levels found in villages without a primary health care worker. However, among children aged 3-59 months who received malaria chemoprophylaxis from a village health worker in addition to treatment there was a 49% reduction in mortality and a 73% reduction in attacks of clinical malaria. The level of protection against malaria achieved by chemoprophylaxis given by village health workers 3-4 years after the chemoprophylaxis programme was started was as high as that obtained shortly after the introduction of the primary health care programme.

Compliance with malaria chemoprophylaxis over a five-year period among children in a rural area of The Gambia

We have reviewed a malaria chemoprophylaxis programme in which Maloprim (pyrimethamine and dapsone) has been administered fortnightly by village health workers (VHWs) to approximately 1500 children each year aged 6-59 months resident in 15 primary health care villages in a rural area of The Gambia over 5 years. Reasonable levels of compliance with chemoprophylaxis have been maintained by many children over this period. this has occurred despite minimal outside supervision and support of the programme. Factors which may have affected the level of compliance in individual villages are identified. Large villages and those where social or political factionalism were evident tended to have low levels of compliance. The attitudes of VHWs and mothers to the programme were determined. Most VHWs cooperated enthusiastically and kept accurate records of compliance, despite receiving no compensation from the villagers for administering chemoprophylaxis. The administration of a drug to prevent illness in children was complementary to the curative service provided by VHWs. The chemoprophylactic was widely acceptable and nearly all mothers stated that the tablets were good for their children's health. However, knowledge of the specific purpose of chemoprophylaxis in the prevention of malaria was limited. Improvements in the programme which may result in higher levels of compliance are discussed.

A genetic linkage map of chromosome 17

We have developed a genetic linkage map of 19 markers (including nine genes) on human chromosome 17, providing 13 reference points along virtually the entire length of this chromosome. The map covers an estimated 149 cM in length (sex-averaged), with a total length of 214 cM in females and 95 cM in males. This sex difference appears to be significant along virtually the entire length of the map. This map will be useful both for providing reference points for fine structure genetic and physical mapping and for genetic linkage studies of diseases, including von Recklinghausen neurofibromatosis and Charcot-Marie-Tooth disease.

A national survey of the prevalence of chloroquine resistant Plasmodium falciparum malaria in The Gambia

In The Gambia, 760 children less than 10 years of age with Plasmodium falciparum malaria were treated with chloroquine (25 mg/kg) and followed-up 2 and 9 d after the start of treatment. 700 children (92.1%) completed the study. The level of in vivo resistance to chloroquine varied by area from 0.4% to 16.4%. Of the 28 children found to have chloroquine resistant malaria, none was ill when seen at the 9 d follow-up and only 3 (10.3%) required further treatment with alternative antimalarials because of persistent high levels of parasitaemia. However, the fact that 30.4% of the children who completed the study had chloroquine in their urine at presentation may have masked the true level of resistance and led to underestimation of the clinical significance of these findings. The blood film at day 2 did not usefully predict resistance. 67 isolates were tested in vitro for chloroquine sensitivity. The mean EC50 was 15.5 nmol/litre, an eight-fold decrease in sensitivity from that of isolates tested in 1982. 8 (11%) of the isolates had EC50s above the WHO reference value for sensitive isolates of 18.3 nmol/litre, with values ranging from 22 to 65 nmol/litre of culture medium. Gambian isolates were sensitive to quinine (mean EC50 = 49.6 nmol/litre).

The epidemiology of Haemophilus influenzae meningitis in children under five years of age in The Gambia, West Africa

Haemophilus influenzae meningitis was studied over a 2-year period in children less than 5 years of age in a population-based, prospective study in The Gambia, West Africa. A total of 77 cases were recorded. The incidence was 60 cases/100,000 children less than 5 years of age and 297 cases/100,000 children less than 1 year of age. The peak prevalence was at the age of 5 months; 83% of the children were less than 1 year old and 45% were less than 6 months old. Only 55% of cases recovered completely. The distance to the nearest hospital was an important predisposing factor for a fatal outcome. Two cases were secondary. Many patients were anemic and underweight. The observations show that H. influenzae meningitis in The Gambia has an incidence as high as that in the USA, but that it has 10-fold more devastating outcome. If the infection is to be prevented by vaccination in The Gambia, immunization will have to be given very early in life.

Cellular immune responses to Plasmodium falciparum antigens in children receiving long term anti-malarial chemoprophylaxis

Fifty-two Gambian children who had received fortnightly chemoprophylaxis with maloprim, (pyrimethamine and dapsone), and 45 receiving placebo, were studied. Cellular immune responses to malaria antigens, measured by lymphoproliferative responses and interferon production, were higher in children who had received prophylaxis than in controls, although the anti-malarial antibody levels were lower. During a one-year period after termination of prophylaxis, there was no increase in the frequency of clinical episodes of malaria in the children who had received Maloprim. These results suggest that chemoprophylaxis for 3 years may lower malaria antibody levels, but does not interfere with the development of protective immunity, perhaps by enhancing cell-mediated immune responses to malaria in protected children.

Lack of an association between acute gastroenteritis, acute respiratory infections and malaria in young Gambian children

The incidence of acute gastrointestinal and acute respiratory infections was measured in 2 groups of approximately 750 Gambian children aged 3-59 months during a 3-year period. One group of children was partially protected against malaria by fortnightly chemoprophylaxis with Maloprim whilst children in the other group were infected much more frequently. Mortality from acute gastroenteritis and from acute respiratory infections was similar in the 2 groups. The proportions of children in each group who complained of gastrointestinal or severe respiratory symptoms on morbidity surveillance were also similar. Thus, no evidence was found to suggest that malaria plays either a direct or indirect role in causing acute gastrointestinal or respiratory infections in young children in The Gambia.

Differential non-responsiveness in humans of candidate Plasmodium falciparum vaccine antigens

Synthetic subunit vaccines to sporozoites, merozoites, and gametes are being developed for malaria. The vaccine strategy assumes that the population to be immunized will respond favorably to these vaccine antigens. Using sera of 35 adults and 50 children from the The Gambia, West Africa, where Plasmodium falciparum is highly endemic, we examined the humoral immune response to candidate malaria vaccine antigens from sporozoites, merozoites, and gametes. We observed widespread restricted immunogenicity to defined parasite antigens in children and adults. HLA typing of adult lymphocytes demonstrated a marked diversity in HLA haplotypes in this population. Our results and those from our studies in mice suggest that genetic factors may partly explain the immunological non-responsiveness. This may necessitate re-evaluation of the malaria vaccine strategy.

Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein

Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.

Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein

Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.

Presence of a non-HLA B cell antigen in rheumatic fever patients and their families as defined by a monoclonal antibody

Numerous investigators have suspected that there is a genetic predisposition to rheumatic fever (RF). In this context we have recently produced a series of monoclonal antibodies directed against B cells obtained from RF patients one of which, labeled D8/17, identifies a B cell antigen present in 100% of all RF patients studied. While the highest percentage of positive cells were exhibited by RF probands (33.5% +/- SE), the percentage of cells in unaffected siblings and parents was 14.6 and 13%, respectively. The percentage of positive cells in APSGN probands, unaffected siblings, and parents was 2.96, 3.86, and 2.8%, respectively. A low level of B cells (5-7%) bearing the D8/17 marker was seen in control patients. The segregation pattern of the phenotypes defined by the percentage of D8/17 positive cells within HLA-typed RF families are consistent with an autosomal recessive mode of inheritance not associated with the human MHC system. We postulate that these phenotypes indicate the presence of at least one necessary genetic factor for susceptibility to RF.

A comparative study of Lapudrine (chlorproguanil) and Maloprim (pyrimethamine and dapsone) as chemoprophylactics against malaria in Gambian children

A comparison has been made of Lapudrine (chlorproguanil) and Maloprim (pyrimethamine +dapsone) as malaria chemoprophylactics when given every two weeks for 3 years to Gambian children under the age of 5 years. Both drugs produced falls in spleen and malaria parasite rates and an increase in packed cell volume. Maloprim, but not chlorproguanil, significantly reduced the incidence of episodes of fever accompanied by malaria parasitaemia. Children who received Maloprim, but not those who received chlorproguanil, grew better than children in the placebo group. This finding suggests that brief clinical episodes of malaria are more important in impairing growth than more prolonged periods of asymptomatic parasitaemia. No serious side-effect attributable to either drug was observed. After chemoprophylaxis had been given for 3 malaria transmission seasons the level of resistance of Plasmodium falciparum to pyrimethamine and to chlorproguanil was about 10%.