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Biomedical subjects

M Alpers

Publications and source records attributed to M Alpers.

At least 37 records · Page 2Linked to original sources
PubMed1990

Plasma glucose and insulin responses in young Papua New Guineans (aged 10-19 years).

A study of rural and periurban children aged 10-19 years in the Tolai population of Papua New Guinea has demonstrated a higher average plasma glucose concentration and relative hyperinsulinaemia after an oral glucose challenge in the periurban group. The findings could not be explained by differences in age or adiposity. In the rural children, plasma insulin concentration remained consistently low throughout the range of glucose tolerance, indicating a high degree of insulin sensitivity. In the periurban children there was a marked increase in plasma insulin concentration with increasing plasma glucose concentration, possibly suggesting the development of insulin resistance, or an antecedent state, and incipient glucose intolerance. In view of the potential public health implications of these findings, further ecological studies of insulin response in children and adolescents would appear warranted. These should include appropriate measures of pubertal development, which is a possible confounding factor not addressed in the present study, as well as addressing the role of nutritional factors.

Adolescent↗
PubMed1990

Failure of chloroquine prophylaxis for falciparum malaria in pregnant women in Madang, Papua New Guinea.

Six hundred and twenty pregnant women, living under conditions of year-round transmission of malaria in a rural coastal area of Madang, Papua New Guinea (PNG), were followed while attending mobile antenatal clinics and receiving chloroquine prophylaxis (300 mg base weekly). Whole blood chloroquine concentrations measured by ELISA from samples collected at delivery indicated a high level of drug compliance in regular attenders. Susceptibility is increased in primigravidae to Plasmodium falciparum but not to other malaria species, with the peak prevalence occurring at nine to 16 weeks gestation. The incidence of P. falciparum infection per person-month was 20% for primigravidae, 25% for those gravida 2, 17% for those gravida 3 or greater, and 14% for non-pregnant nulliparae. Some 8.7% of primigravidae and 9.5% of those gravida 2 had persistent infections. Prophylactic chloroquine is required in this pregnant population because of altered host immunity during pregnancy, but is reduced in efficacy because of chloroquine resistance. Despite this, a missed clinic attendance resulted in a two-fold increase in incidence for all pregnant women, indicating that chloroquine was having some effect.

Animals↗
PubMed1989

Isolation of Fusobacterium nucleatum and electron microscopic observations of spirochetes from tropical skin ulcers in Papua New Guinea.

Tropical ulcer is a disabling condition of the lower leg affecting mainly young adults and older children. Microscopic observations of lesion material have shown fusiform bacilli and spirochetes. We used anaerobic culture techniques to isolate and identify these fusiform bacilli. Electron microscopic (EM) studies were performed to characterize the spirochetes. Material collected on swabs was used to inoculate pre-reduced media and to prepare smears for gram staining; the swabs were placed in fixative for EM study. After incubation, colonies containing fusiform bacilli were subcultured. The anaerobic gram-negative fusiform isolates were identified as Fusobacterium nucleatum using biochemical reactions, hemagglutination testing, and reaction of antigen preparations of the isolates and ATCC strains in serological tests with rabbit antisera. EM observations of negatively stained spirochetes revealed an 8-16-8 periplasmic flagellar arrangement. F. nucleatum and spirochetes may participate in the pathogenesis of this polymicrobic infection.

Adolescent↗
PubMed1989

Asthma and chronic airflow limitation in the highlands of Papua New Guinea: low prevalence of asthma in the Asaro Valley.

The prevalence of asthma in the South Fore region of Papua New Guinea was found to be 7.3%, which is thought exceptionally high for highland areas in this country. To investigate the prevalence of asthma and of chronic airflow limitation in a different highland region with similar living conditions, adults and children from 7 villages in the Asaro Valley were interviewed. Questions were asked about smoking history and about past and present symptoms of cough, of shortness of breath, of chest tightness and of asthma. Of 743 adults interviewed, 206 underwent a clinical study with measurements of lung function, bronchial responsiveness and skin prick tests. Dust was collected from the floors and blankets of 36 houses for counts of house dust mites. We did not find any children with symptoms of asthma. Only 2 adults (0.3%) had symptoms consistent with asthma, and a further 6.2% had symptoms and/or lung function consistent with chronic airflow limitation. Most bronchial hyperresponsiveness was associated with asthma or with chronic airflow limitation. The prevalence of atopy was similar in the Asaro and South Fore populations, but the South Fore had higher house dust mite counts in blanket dust. The low prevalence of asthma in the Asaro Valley is unexplained in terms of factors normally associated with asthma. Because asthma in this area does not appear in childhood and only develops in a small proportion of adults, it may be of different aetiology to asthma in Caucasian populations.

Adult↗
PubMed1986

Effect of dietary protein levels on urea utilization in Papua New Guinea highlanders.

Ability to utilize urea nitrogen for body protein synthesis was examined with Papua New Guinea (PNG) highlanders and Japanese (JPN). Eight male PNG highlanders and 8 male JPN were fed on a low protein diet containing 0.55 g protein/kg or an adequate protein diet containing 1.34 g protein/kg for 1 or 2 weeks. The fate of 15N was measured after oral administration of 15N-labelled urea. There was no difference in 15N incorporation into serum protein between PNG highlanders and JPN receiving low protein diets. On the other hand, on the adequate protein diet, 15N incorporation in PNG highlanders was similar to that on the low protein diet, in contrast to that in JPN which was hardly detected in the adequate protein diet. When PNG highlanders take more protein than protein in their usual diet, they effectively incorporate ingested protein into their body protein and urea nitrogen is utilized for synthesis of body protein.

Adolescent↗
PubMed1985

Blood pressure in Papua New Guinea: a survey of two highland villages in the Asaro Valley.

The results of a population survey of blood pressure in the adult residents of two highland villages in the Asaro Valley, Papua New Guinea are reported. The survey was conducted in 1983 as part of a wider epidemiological investigation of non-communicable disease in Papua New Guinea. Response to the survey was 95%, and 308 subjects were examined. Population estimates of both systolic and diastolic blood pressures were low and there was a virtual absence of hypertension, as defined by internationally recommended criteria. There was no evidence of a rise in blood pressure with age, and the association between blood pressure and indices of obesity was weak. These findings are consistent with previous studies of blood pressure in traditional Papua New Guinean societies. The two villages differed with respect to their degree of modernisation. An unexpected finding was that in both sexes, both systolic and diastolic blood pressures were higher in the more traditional village. In each case, these differences were consistent across the three age groups examined, and they could not be explained by differences between the villages with respect to the indices of obesity. Analysis of variance showed that the higher blood pressures in the more traditional village were most unlikely to be due to chance (p less than 0.001). The explanation for this finding remains obscure.

Adult↗
PubMed1984

Iron and infection in infancy--report on field studies in Papua New Guinea: II. Protocol and description of study cohort.

The protocol for a prospective, randomized, double-blind, placebo controlled trial of iron prophylaxis in infants is described. Specific design points discussed include (i) control and "blind", (ii) dose, preparation and age of administration of iron, (iii) standardization of morbidity recording, (iv) data analysis and (v) ethics. The study cohort at birth is described and rationale for exclusions and reasons for withdrawals are discussed. An initial descriptive comparison is made of treatment and control groups entering the trial at two months of age.

Age Factors↗
PubMed1984

Serotypic variation of culture-adapted isolates of P. falciparum.

Culture adapted isolates of P. falciparum had different growth patterns (P less than 0.01) when cultured in the presence of sera obtained from 31 healthy Papua New Guinea residents. Both enhancement and suppression of growth was observed. Less variation was observed using an indirect immunofluorescent antibody method directed against schizont antigens, and no correlation between the two assays was found. This bioassay is assessed as a basis for serotyping P. falciparum strains.

Animals↗
PubMed1984

Parasitologic and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea.

Bancroftian filariasis has been reported in several areas of Papua New Guinea. The epidemiologic features and natural history of Wuchereria bancrofti infection in this geographic region, however, have not been well-defined. The objective of this study was to assess the parasitological and clinical features of bancroftian filariasis in a community in East Sepik Province, Papua New Guinea. In a village of 99 individuals, the overall prevalence of microfilaremia was 68%. The microfilarial carrier rate was high in those less than or equal to 10 years (62%), remained elevated in the 11-20, 21-30, and 31-40 age groups (42-55%), and peaked in subjects greater than or equal to 41 years old (90%). The geometric mean level of parasitemia in all subjects with patent infection was 3,198 microfilariae/ml blood. This value was 78 parasites/ml in the less than or equal to 10-year-old age group, increased to 1,753 in 21 to 30-year-olds and was markedly elevated in subjects greater than or equal to 41 years old (6, 792 microfilariae/ml). Acute symptoms of filariasis (lymphadenitis and lymphangitis) were initially noted in individuals between the ages of 11 and 20 years (30%). Obstructive disease, manifested as elephantiasis and hydroceles, was present in 64 and 79% of 31-40 and greater than or equal to 41-year-olds, respectively. These data suggest that intense transmission of W. bancrofti infection occurs at an early age in this area of East Sepik Province; patent infection remains high in older age groups. Irreversible lymphatic obstruction develops 20-30 years after initial infection and may be associated with either amicrofilaremia or microfilaremia.

Adolescent↗
PubMed1984

Glucose tolerance in a highland population in Papua New Guinea.

A diabetes survey was conducted in the highlands of Papua New Guinea in June 1983. Two villages in the Asaro Valley, Eastern Highlands Province, were selected for study. The subjects were of Melanesian ancestry, and were free of Austronesian genetic admixture. The response rate was 95% and 308 subjects were examined. As defined by current WHO criteria, there was a total absence of non-insulin-dependent diabetes (NIDDM) in these communities. The prevalence of impaired glucose tolerance (IGT) was 2%. These estimates of glucose intolerance are the lowest yet to be reported from the Pacific, using currently accepted diagnostic criteria and standardized survey methods. The 2-hr plasma glucose and insulin concentrations were positively correlated in both sexes. Of the two villages studied, one had undergone a greater degree of acculturation than the other. Both the total distribution and the mean value of 2-hr plasma glucose concentration were lower in the more traditional village, and these findings could not be explained by differences in age or obesity between the two communities. Mean 2-hr plasma insulin concentration did not differ significantly between the two villages, and was very low in both. The results of this study support the theory that Melanesians free of Austronesian genetic admixture are relatively, though not absolutely resistant to the deleterious influence of acculturation upon glucose tolerance seen in other Pacific populations. However, the notion that in this population cultural change has been insufficient, or of too recent onset for a deterioration in glucose tolerance to be manifest cannot be excluded.

Adult↗
PubMed1983

A microassay for detecting merozoite inhibition suitable for routine laboratory use.

A micro semiautomative assay of merozoite inhibition antibody has been developed, based on incorporation of radiolabeled isoleucine into parasite protein. The assay has been validated using 44 sera from healthy blood donors in Madang. Inhibition of uptake of label occurred in 43.2% of tests, while an enhancement of uptake was demonstrated in 4.7%. This assay has 'potential' for both seroepidemiological studies, and for providing a mechanism of biotyping wild isolates.

Animals↗
PubMed1982

Sulfadoxine-pyrimethamine for the treatment of acute malaria in children in Papua New Guinea. I. Plasmodium falciparum.

Chloroquine-resistant Plasmodium falciparum malaria is increasing in prevelance in Papua New Guinea and alternative therapies for acute malaria are being sought. A trial of sulfadoxine-pyrimethamine for the treatment of acute falciparum malaria in children has been carried out in Madang, Papau New Guinea. Eighty-five children were treated with sulfadoxine-pyrimethamine, either alone or in combination with a single 10 mg/kg dose of chloroquine. Of 78 children completing 28-days follow-up, treatment failures occurred in 15 (19.2%) and of these, 8 (10.3%), are believed to be sulfadoxine-pyrimethamine resistant; the others remain equivocal. There was no advantage in this study in combining a single dose of chloroquine with sulfadoxine-pyrimethamine; indeed, this combination was associated with an increased incidence of vomiting. It is argued that sulfadoxine-pyrimethamine should not become the standard presumptive treatment for acute malaria in Papua New Guinea.

Child↗
PubMed1982

Sulfadoxine-pyrimethamine for the treatment of acute malaria in children of Papua New Guinea. II. Plasmodium vivax.

In Papua New Guinea, Plasmodium falciparum and P. vivax are common causes of acute malaria in children and P. malariae an uncommon cause. The increasing prevelance of chloroquine-resistant strains of P. falciparum in Papua New Guinea has prompted the search for alternatives to chloroquine as standard presumptive treatment. Sulfadoxine-pyrimethamine, either alone or in combination with a single dose of chloroquine, was compared with chloroquine alone for treatment of acute vivax malaria in children in Madang. Fever resolution was slowest in the group treated with sulfadoxine-pyrimethamine alone, and time to clearance of parasitemia was significantly longer in this group (P less than 0.001). Where possible, species identification should be undertaken in acute malaria and cases of P. vivax treated with chloroquine.

Child↗
PubMed1980

Blood lead levels in Papua New Guinea children living in remote area.

Improved contamination-free micro blood sampling and chemical analysis techniques were used to study the lead in blood (Pb--B) levels in 100 Papua New Guinea children living in a remote area. Six soil samples from different locations in the area were also chemically analysed as a check on environmental conditions. The mean value for Pb--B was 5.2 micrograms/100 ml with a range of 1.0--13.0 microgram/100 ml. The standard deviation was 2.5 micrograms/100 ml. The results indicate much lower Pb--B levels for children living in a remote area than the earlier commonly reported levels for similar areas. These results indicate a need to reappraise the comparisons often made with Pb--B levels for urban children.

Child↗
PubMed1980

Plasmodium falciparum strains from Papua New Guinea: culture characteristics and drug sensitivity.

Seven strains of Plasmodium falciparum from Papua New Guinea have been established in continuous in vitro culture. Samples with a high initial parasitaemia were more likely to form continuous lines, possibly due to the time required for transport of infected blood samples from Papua New Guinea to laboratories in Australia. Most but not all established lines were resistant to chloroquine and all were resistant to pyrimethamine, possibly reflecting the parasite strain characteristics in that region.

Adolescent↗