A child's growth achievement depends on his genetic endowment and the environment in which he lives; Comparative studies of children of similar racial origin but growing under different environmental conditions have shown differences in their body size and shape. In general higher income families produce offspring with higher mean birth weight. This is largely due to better nutrition and care of mothers during pregnancy and childhood. Children from higher socioeconomic groups are on an average larger in size in terms of weight, height, head circumference, midarm circumference, crown-rump length and leg length. This is largely due to a better home environment including sanitation, nutrition, health and care enjoyed by the better-off children. .Generally urban children are larger than rural children mainly due to economic differences between the two areas. In most countries the secular trend to children getting larger still continues reflecting an improvement of living conditions with time. Unlike body size, body shape is less influenced by the environment and the change in body proportion brought about by environment is not permanent. In developing countries, children from higher socioeconomic families have generally thicker skinfolds. On the average, infants and preschool children of European ancestry have thicker triceps skinfolds compared with Negroes and Asians living in comparable environments. It is possible that this is due to long term adaptation to different climatic conditions.
The author examines migration trends in Malay villages. "This report deals with the case of Galok, a settlement opened in the last decade of nineteenth century about 40 kilometers up the Kelantan River, based on field data collected in 1970/71 and 1984." The low rate of population growth due to migration is analyzed, with a focus on the impact of rural-urban migration and changes in household composition. (SUMMARY IN ENG)
This paper reports the experimental transmission of a bird parasite into jirds. Infective larvae of Cardiofilaria nilesi obtained from laboratory colonized Coquillettidia crassipes mosquitoes which had fed on an infected chicken were inoculated subcutaneously into jirds. The number of larvae per jird varied from 10 to 228. Microfilaraemia appeared 22 to 89 days after inoculation of the infective larvae. Experiments were carried out with 24 jirds through six generations extending over a period of 22 months and 17 produced patent infections. At present 8 infected jirds are being maintained in the laboratory; their patent periods ranging from 6 to 13 months. However, the longest patent period observed was about thirteen months. The percentage of adults recovered in autopsied jirds ranged from 0 to 40 with an average of 16. The chicken showed a microfilarial periodicity with the peak microfilarial density around 2200 hours. However, in jirds there was a change in sub-periodicity. This model in the jird may be very useful for the screening of filaricides and in immunological work.
Matched MeSH terms: Filarioidea/growth & development*; Microfilaria/growth & development
Injectable vitamin A was given to six pregnant beef cows in their last third of pregnancy to study the effect of this vitamin in their calves. Average birth weight and growth rate of calves from the treated cows were higher than that of calves from the nontreated cows. Prepartum vitamin A injections also resulted in a significant increase (P less than 0.05) in the mean corpuscular volume (MCV), total serum protein and globulin fraction of serum protein in calves of treated cows.
Studies on larval population densities and adult emergence rates of the Brugian filariasis vectors Mansonia bonneae Edwards and Ma. dives Schiner were conducted in freshwater swamp forest bordering the Sadong River, Serian District, Sarawak, East Malaysia, during 1984-85. Three species of aquatic host-plants in the Family Araceae were identified as supporting immature stages of the Ma. bonneae/dives complex. Proportions of positive plants were 4.7%, 6.5% and 3.4% with 6.4 +/- 2.6, 7.3 +/- 2.8 and 10.1 +/- 1.1 larvae per positive plant, respectively, for the plant species Homalomena cordata Schott, H. rostrata Griffiths and Hydrostemma motleyi (Hook. f.) Mabberley. These data indicate no significant preferences between the three types of host-plant. Detailed monitoring of the host-plant H. cordata revealed no significant monthly fluctuations in larval density per plant nor the proportion of positive plants. 11.6% of larvae were Ma. dives and 88.4% were Ma. bonneae. Mean daily yields of Ma. bonneae/dives adults per square metre of H. cordata vegetated water surface were 0.45 males plus 0.57 females during the wet season (December-February) compared with 0.2 males plus 0.31 females during the dry season (June-August). Thus output of adults per plant was approximately halved, and suitable breeding areas were further reduced, during the dry season. By extrapolation from these rates, a crude mean estimate for productivity of Ma. bonneae/dives females is 1.6 million per hectare per annum in swamp forest habitats vegetated with any of the host-plants studied.
This study was initiated to determine the mechanism of iron-uptake in Salmonella typhi. When stressed for iron, microorganisms produce siderophores to obtain the necessary nutrient. Generally two types of siderophores exist: the phenolate-type predominantly produced by bacteria and the hydroxamate-type commonly secreted by fungi. Results of this investigation showed that S. typhi produced siderophores of the phenolate-type since culture supernatant of the organism grown under iron-deprivation supported the growth of the phenolate-dependent auxotroph. The culture supernatant when extracted for phenolate siderophores, also supported the growth of the phenolate auxotroph but not the hydroxamate auxotroph. Production of phenolate-type siderophores were further confirmed using biochemical assays. These results showed that S. typhi utilized the high-affinity iron transport system to obtain the necessary iron.
Matched MeSH terms: Arthrobacter/growth & development
Two separate observations from recent electrophoretic studies of the systematics and population genetics of laboratory-reared populations which had a long history of colonization in various laboratories, were found to be inconsistent with the present study which used wild-caught populations from East Malaysia. Reanalysis of the two data sets generally indicated a low amount of genetic variation in laboratory colonies. The latter is characterized by higher frequency of monomorphic loci, low average heterozygosity values and, in one extreme case, no variability at two loci. However, natural populations of An. balabacensis and An. leucosphyrus showed more protein variability by the use of polyacrylamide gel electrophoresis. Since laboratory-maintained mosquitoes are genetically and phenotypically different from those in the field, results of laboratory studies on the systematics and population genetics of Anopheles species complexes may be biased.
Matched MeSH terms: Animals, Laboratory/growth & development
Cyclic AMP phosphodiesterase (PDE) partially purified from roots of Vigna mungo exhibited optimum activity at pH 5.5 to 6.0 and maximum enzyme activity at 50 degrees C. Levels of PDE activity in roots remained relatively constant from the first to the eleventh day after germination; on the twelfth day there was a 400% increase in PDE activity. The enzyme was stable for at least 48 hours at 28 degrees C, retaining 92% of its original activity. Plant growth hormones including gibberellic acid, indoleacetic acid and kinetin at 1.0 and 10.0 microM concentrations did not have any significant effect on enzyme activity. Nucleotides tested including cyclic 2'3' AMP, cyclic 2'3' GMP completely abolished enzyme activity at 1.0mM while cyclic 3'5' GMP, cyclic 3'5' GMP, 2'deoxy 5' ATP, 2'deoxy 5'GTP and 5'ADP were also inhibitory to the enzyme. The enzyme was stimulated by Mg2+, Fe2+ and NH4+ while Cu2+ and Fe3+ were inhibitory. Theophylline, caffeine, phosphate, pyrophosphate and EDTA were inhibitory to the enzyme.
The fertility and parameters of population growth of the Semai Senoi of Malaysia are studied by using a two-census method based on nonstable population theory. Semai fertility is shown to be moderately high; female completed fertility is 7.42 children and the crude birth rate is greater than 0.050. Previous estimates of Semai mortality rates are also moderately high but are insufficient to balance birth; thus, the overall rate of growth is presently nearly 2%. Compared with an earlier description of the pre-1969 Semai population, fertility has increased markedly leading to a nearly threefold increase in the annual growth rate.
The ability of passage in HeLa cells to attenuate flaviviruses was investigated for three different strains of the mosquito-borne West Nile (WN) virus and two tick-borne viruses, louping-ill and Langat. One strain of WN virus, Sarawak, was attenuated 4000-fold for adult mice by intraperitoneal or intranasal challenge after six HeLa passages. The HeLa-passaged virus was also found to be antigenically different and temperature-sensitive in its growth characteristics compared with the parent. After six HeLa cell passages the Egypt 101 and Smithburn strains of WN virus lost their ability to infect monkey kidney cells and no longer killed adult mice, although inoculated animals became sick for several days. In contrast, two tick-borne flaviviruses remained as virulent for mice after six HeLa passages as the parent non-HeLa-passaged virus. Neither of the tick-borne viruses exhibited characteristics associated with temperature sensitivity. The results, therefore, indicate that the mosquito-borne, but not tick-borne, flaviviruses can be attenuated by very few passages in HeLa cells. This observation may provide a model system with which to analyse the molecular basis of attenuation and/or virulence of mosquito-borne flaviviruses.
Matched MeSH terms: Flavivirus/growth & development
Twelve goats were inoculated with 40,000 third-stage Haemonchus contortus larvae and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. More worms established in the fundic, than in the middle or pyloric thirds of the abomasum. Early development occurred within the mucosa; emergence into the lumen started between 7 and 11 days after infection. By 4 DAI, all worms had completed the third moult to the L4 stage. At 11 DAI the majority of the worms were adults. A mean of 13.2% of the female worms had eggs in their uteri at 18 DAI; by 21 DAI more than half of the female worms had eggs in their uteri. The development of H. contortus was essentially similar to that described in sheep.
Twelve goats were inoculated with 20,000 infective larvae of Trichostrongylus colubriformis and two were killed on each of Days 4, 7, 11, 14, 18 and 21 after inoculation (DAI). The number of worms that established, and the site of development were recorded. Most of the worms established within the first 3 m of the small intestine. There was little relocation or loss of nematodes after establishment. The worms started to migrate from the mucosa to the lumen 11 days after infection. At 4 DAI, 63% of the worms were still at the late L3 stage; the remainder of the worm population had completed the third moult to the L4 stage. The population at 11 DAI comprised largely young adults. When 21 DAI was reached, about 57% of the female worms had eggs in their uteri.
The leaf-monkeys, Presbytis cristata and Presbytis melalophos, experimentally infected with subperiodic Brugia malayi, have been used for studies on the pathoimmunology of the infection and the screening of potential filaricides during the last 6-8 years, and considerable information on the pattern of microfilaraemia and adult worm recoveries have been obtained. The prepatent periods in 97 P. cristata and 45 P. melalophos, each infected with about 200 infective larvae, were similar, these being approximately 70 and 68 days respectively. Although all infected animals became microfilaraemic, the peak geometric mean count was much higher in P. cristata than in P. melalophos, this being 182.0 and 65.8 per ml blood respectively. Mean adult worm recovery expressed as the percentage of the infective dose was 4.7% and 2.5%, respectively. Most worms were recovered from the sacral nodes/thoracic duct or inguinal lymph nodes in these animals. In view of the higher worm recovery and the higher peak microfilaraemia attained, it is concluded that P. cristata is a better model for the infection than P. melalophos.
A simple and sensitive double-antibody radioimmunoassay for human growth hormone (HGH) was developed, optimised and validated. The anti-hGH sera raised in 2 rabbits were highly specific with low cross-reactions of 0.19% and 0.3% with human placental lactogen and 0.21% and 0.13% with human prolactin. The mean sensitivity of the assay determined from 28 assays was found to be 0.4 +/- 0.2 mIU/L. Mean recovery of added exogenous hGH was 98.8 +/- 6.8%. Linearity studies of samples diluted at 1:2, 1:4 and 1:8 gave values of 101.3 +/- 5.3%, 109.6 +/- 13.4% and 97.3 +/- 13% respectively of those expected. The reproducibility of the assay was good; within assay coefficient of variation for serum samples with GH concentrations of 2.7, 13.6 and 28.2 mU/l ranged from 5.1 to 8.3% while the inter-assay precision varied from 4.9 to 10.3%. The in-house assay showed good correlation (r = 0.96, p less than 0.001) with a commercial HGH RIA kit (Dainabot, Japan). A reference normal adult fasting GH level of less than 7 mIU/l was established from 95 samples assayed by this method.
The known filaricides, suramin and diethylcarbamazine citrate, were tested against subperiodic Brugia malayi infection in the leaf-monkey, Presbytis cristata. As expected, intravenous suramin at 10 mg/kg daily x 5 days or 17 mg/kg weekly x 5 weeks, did not show any microfilaricidal activity, but substantially reduced the recovery of live adult worms to 50.6% and 13.6% of controls respectively. Oral diethylcarbamazine citrate at 6 mg/kg daily x 6 or 10 days reduced final microfilarial counts to 30% of initial counts four weeks post-treatment and adult worm recovery was reduced to 4.5% and 0% of controls respectively. Although the antifilarial activity of these drugs against the infection in this non-human primate model appears to be similar to that seen in man, these results have to be confirmed using larger groups of animals.
Matched MeSH terms: Brugia/growth & development; Microfilaria/growth & development