PubMed Health⌕ Search

Biomedical subjects

A S Muller

Publications and source records attributed to A S Muller.

At least 19 recordsLinked to original sources
PubMed2002

Down-regulation of GPx1 mRNA and the loss of GPx1 activity causes cellular damage in the liver of selenium-deficient rabbits.

The effects of 10 weeks of dietary selenium and/or vitamin E deficiency (< 0.03 mg Se and 1.5 mg vitamin E per kg diet) on body Se and vitamin E stores and on the down-regulation of liver cellular glutathione peroxidase (GPx1) and plasma glutathione peroxidase (GPx3) were examined in growing female New Zealand White rabbits in comparison to Se (+ 0.40 mg Se/kg diet) and/or vitamin E (+ 150 I.U./kg diet) supplemented controls. Additionally plasma lactate dehydrogenase (LDH) activity, liver thiobarbituric acid-reactive substances (TBA-RS) and liver protein carbonyls were measured to assess the development of oxidative stress during an alimentary Se and/or vitamin E deficiency. Significantly decreased concentrations of Se and vitamin E in plasma (Se: - 70%; vitamin E: - 87%) and liver (Se: - 90%; vitamin E: - 95%) indicated an efficacious Se and vitamin E depletion of the rabbits within 10 weeks. GPx1 messenger RNA levels (GPx1 mRNA) in the livers of Se-depleted rabbits were down-regulated to 1/3-1/8 of the Se supplemented controls. GPx1 enzyme activity in the livers of Se-deficient rabbits declined to 10% of the Se-supplied control rabbits. A significantly elevated LDH activity in the blood plasma of Se- and vitamin E-deficient rabbits indicated a general impairment of tissues. Markedly increased TBA-RS concentrations and protein carbonyl contents in the livers of Se- and vitamin E-deficient rabbits gave further evidence for severe oxidative damage of cellular lipids and proteins during an alimentary Se and/or vitamin E deficiency. Both a full expresssion of GPx1 attained by dietary Se supplementation and dietary vitamin E supply effected an almost complete protection against oxidative cellular damage of the liver.

Animal Feed↗
PubMed1995

Splenomegaly in Baringo District, Kenya, an area endemic for visceral leishmaniasis and malaria.

The relationship between splenomegaly and visceral leishmaniasis (VL) was investigated during a cross-sectional study in 2,941 individuals in Baringo District, Kenya, where both malaria and VL are endemic. Spleen size was correlated with presence of malaria parasites in thick blood films and with evidence of present or past Leishmania donovani infection as determined by serology and history. Marked splenomegaly (Hackett grade 3 or greater) significantly correlated with present or previous leishmanial infection (chi 2 = 53.5; p < 0.001) whereas moderate splenomegaly (Hackett grade 1 or 2) significantly correlated with malaria parasitaemia (chi 2 = 73.03; p < 0.001). The presence of antimalarial antibodies did not contribute to the differentiation of the cause of splenomegaly. The diagnostic significance of splenomegaly in this population is discussed.

Adolescent↗
PubMed1994

Studies on the prevalence of leishmanin skin test positivity in the Baringo District, Rift Valley, Kenya.

The leishmanin skin test (LST) was applied in 26 clusters of an average of 97 individuals in Baringo District, Kenya. These clusters were centered around recent cases of visceral leishmaniasis (VL). Of 2,411 individuals tested, 254 (10.5%, 155 males and 99 females) had a positive reaction. Among cured VL patients, the frequency was approximately 30% and no sex difference was observed. In the population as a whole, LST positivity increased with age to a stable level from approximately 15 years of age, reflecting an endemic situation. The level of LST positivity was 25-30% and 10-15% in males and females, respectively. Uninfected household contacts of VL cases had a higher frequency of LST reactivity than the rest of the population. This relationship was significant only in females and children, the prevalence ratio being 2.3 (95% confidence interval 1.3-4.1), 1.9 (1.1-3.5), and 1.4 (0.8-2.5) for females, children, and males, respectively. The frequency of LST positivity was higher individuals living in wood houses than in individuals living in house with mud or stone walls. Again, this difference was significant only in females and children (P = 0.02 and P = 0.04), but not in males (P = 0.7). The results suggest that children and women are exposed to the parasite in or around their houses, whereas adult males are, in addition, exposed elsewhere.

Adolescent↗
PubMed1994

Epidemiology and clinical manifestations of visceral and cutaneous leishmaniasis in Baringo District, Rift Valley, Kenya. A literature review.

Visceral leishmaniasis (VL), caused by Leishmania donovani, is endemic in Baringo District, Kenya. The disease has a focal distribution in the dry, hot areas below 1500 metres. Infections may be characterized as follows: 1) asymptomatic, 2) subclinical and self-limiting (not medically identifiable), and 3) clinically manifest disease (that is medically identifiable). Half of the reported VL patients are between 5 and 14 years of age and 66% of them are males. The reasons for the focal distribution and for the age and sex preference are discussed. Phlebotomus martini is the vector of the parasite, and man is the only known reservoir. Cutaneous leishmaniasis (CL), due to Leishmania major, is rare in humans, but underreporting is likely. The vector, Phlebotomus duboscqui, is mainly found in animal burrows where it feeds on rodents which are frequently infected. A human case of a mixed L. donovani and L. major infected. A human case of a mixed L. donovani and L. major infection has been reported in this dual focus of VL and CL.

Adolescent↗
PubMed1991

Differential birthweights and the clinical relevance of birthweight standards in a multiethnic society.

Using a computer-stored database, birthweights and related variables over 25,000 infants born in Amsterdam (The Netherlands) were analysed retrospectively. Only after allowing for maternal height, did the difference between mean birthweights of Dutch and Asian infants disappear, whereas Negroid and Mediterranean infants continued to show respectively lower and higher means than the others. These results confirm that the birthweight standards presently used are inappropriate for detection of deviant weight in non-Dutch groups.

Birth Weight↗
PubMed1984

Pertussis in a rural area of Kenya: epidemiology and results of a vaccine trial.

Pertussis surveillance was carried out from 1974 to 1981 among a population of 24 000 in the Machakos district of Kenya by fortnightly or monthly home visits. The diagnosis was verified by a physician according to standard criteria including bacteriological and haematological findings. Since not all cases could be diagnosed with certainty, each case was scored from 0 to 3 according to the probability of pertussis. During the surveillance a vaccine trial was carried out: 436 children receiving two diphtheria-pertussis-tetanus (DPT) immunizations 6 months apart were compared with 466 children receiving the conventional three doses 3 months apart.The agglutinating antibody response was determined in approximately 100 children in the trial at 1 month, 2 years, 3(1/4) years and 4(1/4) years after completing the immunizations. The results showed no difference in titres between the 2-dose and 3-dose groups at one month after the last immunization. Waning of antibodies proceeded more rapidly in the 2-dose group, the differences between both groups becoming statistically significant after 2 years.Two epidemic waves of pertussis occurred during the seven years of surveillance. A third epidemic did not materialize, possibly because of increased herd immunity due to the immunizations. The case fatality rate was 1% and was highest (2.6%) among infants. During the 4 years following completion of the immunizations, 36 children in the vaccine trial, based on the cumulative probability of pertussis, yielded 16.7 cases. The number of "cases" so defined did not differ significantly between the two immunized groups, although there was a suggestion of greater protection with the 3-dose schedule. Compared with the observed number of "cases" among 1281 children of the same birth cohorts not included in the trial, the reduction among the trial children (both immunized groups) was 54%.

Child, Preschool↗
PubMed1980

Agents affecting health of mother and child in a rural area of Kenya. XVII. Population growth in 1974-1978.

Demographic information was collected on a fortnightly basis between 1974 and 1978 in the framework of the Machakos Project. Results reported here deal with population size and increase on a de jure and de facto basis, population composition by age and sex, and crude birth and death rates. The results show that the study area is characterized by somewhat lower fertility than the national average of Kenya and much lower mortality. In addition, there is net-in-migration into the study area and the overall result is very rapid population increase. It is argued that underreporting of births and deaths, has been kept to a minimum due to the design that was used together with the use of several control measures.

Adolescent↗
PubMed1980

Agents affecting health of mother and child in a rural area of Kenya. XVIII. Fertility, mortality and migration in 1975-1978.

The results reported here are based on age-specific rates and are, therefore, more sensitive and meaningful as indicators of fertility and mortality than the crude rates mentioned in the previous article. The results confirm that, compared to world standards, the study area is characterized by a high level of fertility and a fairly low level of mortality. Fertility and mortality are, however, lower in the study area in comparison to Kenya as a whole. Another characteristic is high population mobility which is of two types: temporary migration of absent members of the population, and permanent in- and out-migration.

Adolescent↗
PubMed1979

Machakos Project Studies: agents affecting health of mother and child in a rural area of Kenya. XVI. The outcome of pregnancy.

The outcome of pregnancy of all women belonging to the study population of the Machakos project studies who delivered during 1975 and 1976 is presented. The birth-rate was 43.0 per 1,000 population per year, the fertility rate was 235 per 1,000 women 15--44 years of age per year. Unexpected low mortality rates were found; stillbirths, neonatal and infant death rates were respectively 29.8 per 1,000 total births and 22.5 and 50.0 per 1,000 live births. One maternal death occurred among the 2,223 deliveries. Maternal age of less than 25 and over 34 years, a history of previous perinatal death and breech delivery were associated with higher perinatal mortality. Parity, marital status, birth-interval and maternal height were not associated with a difference in outcome of pregnancy. The stillbirth rate among the children born in hospital (26.4%) was 4.4% compared with 2.4% among the children born at home, neonatal and infant death rates were the same. Half of all perinatal deaths were caused by either prematurity or birth trauma, 75% of all infant deaths after the first week of life were caused by infections.

Adolescent↗
PubMed1978

Machakos Project Studies: agents affecting health of mother and child in a rural area of Kenya. VII. The incidence of diarrhoeal disease in the under-five population.

The outcome of three years of fortnightly diarrhoea surveillance of about 4000 children under the age of five is described. The two-weekly incidence of diarrhoea in children in the age group 0-5 months, 6-11 months and 12-23 months, who were reported and/or observed to be ill, was 3.4%, 5.6% and 3.4% respectively. A decline in the attack rates of diarrhoea not associated with measles at the end of 1975 and the beginning of 1976 corresponds with a similar decline in the incidence of measles and malnutrition. Initially diarrhoea information was only obtained from children who where reported and/or observed to be ill; later on, all mothers were questioned about their children's diarrhoea experience at the moment of the fieldworkers's visit or in the preceding two weeks. This yielded a four to sevenfold increase in diarrhoea incidence. Thus, diarrhoea appears to be a common condition among under-fives which is not necessarily considered to be an illness by the mother.

Attitude to Health↗
PubMed1978

Agents affecting health of mother and child in a rural area of Kenya. XI. Antibodies against rotavirus in sera from children living in the Machakos District of Kenya.

207 sera from children under 5 years of age and living in the Machakos District in Kenya were tested in the Complement Fixation Test for antibodies against rotavirus. Two different antigens were used. The superiority of 'O' antigen over Nebraska calf diarrhoea virus antigen was confirmed. After a fall to 29 percent in the 6-8 months age group, the percentage of children with antibodies quickly rises with age to 80 percent at the age of 24 months and to practically 100 percent at the age of 30 months. This age-immunity curve suggests that the majority of children contract infections with rotavirus between 6 and 23 months of age. This is conform the pattern usually found in temperate climate countries.

Antibodies, Viral↗
PubMed1978

Agents affecting health of mother and child in a rural area of Kenya. X. Haemagglutination inhibiting antibodies against influenza A (H3N2) and influenza B virus in sera from children living in the Machakos District of Kenya.

In the framework of the Machakos Project bloodcollections from random samples of children under 5 years of age and living in a rural area of Kenya were done with regular intervals, Serum samples of two collections were tested for haemagglutination inhibiting antibodies against influenza A and B viruses. The children had been exposed to the Hong Kong/1/68 (H3N2) virus or its variants during one, two or three episodes of circulation and probably to only one epidosde of B/Hong Kong/8/73 virus. The results can be explained by the assumption that 30-40 percent of non-immune children were infected per epidosde of exposure to influenza A and not more than 12 percent per episode of influenza B circulation.

Antibodies, Viral↗