Longitudinal study of the frequency and duration of breastfeeding in rural Bangladeshi women.

A 27-month longitudinal study of 140 Bangladeshi mothers living in three tea gardens examined the effect of maternal factors (mother's age, number of live births, birth interval, and mother's work status) and sex of the infant on the duration and bout frequency of breastfeeding over 8-hr daytime periods. Prolonged breastfeeding of the infant was observed, but there was a sharp decline in duration of breastfeeding over the first 6 months, followed by a more gradual diminution thereafter. The feeding bouts showed a different pattern, with a more gradual decline over time. Housewives consistently showed a greater duration and bout frequency than women in paid employment as tea-pluckers. Over the first 6 months, primigravid mothers breastfed more frequently, but not thereafter. Older mothers (>35 years of age) breastfed with higher frequency during the first 2 months, but thereafter, the bout frequency decreased with increasing age of the infant. Over the 27-month study, maternal work status was the main factor associated with the duration and frequency of breastfeeding, with significantly higher frequency and duration among housewives. However, in the first 6 months after birth, there was very little difference in frequency or duration of breastfeeding between tea-workers and housewives, indicating that working mothers probably adjusted their time to breastfeed their infants before going, or after coming back, from work.     

用混合粘合剂碳糊电极测定丁螺环酮

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Viral infections in the mouth

Oral hairy leukoplakia (OHL) and Kaposi's sarcoma (KS) are commonly encountered in the HIV-infected patient. A unique feature of OHL is non-cytolytic high level of replication of Epstein–Barr virus (EBV) in the glossal epithelium. The expression of viral-encoded anti-apoptotic proteins concomitant to replicative proteins probably underlies this phenomenon. The question of whether OHL arises from activation of EBV latent in the tongue, or from superinfection by endogenous EBV shed via non-glossal sites or by exogenous EBV remains unresolved. Human herpesvirus 8 (HHV8) is now seen as necessary but not sufficient cause of KS. Expression of HHV8-encoded oncogenic proteins in endothelial cells probably explains the aberrant proliferation of these cells in KS lesions. Studies into why KS is so commonly observed at the palate in HIV-infected patients may provide important clues to its pathogenesis.     

Longitudinal growth of Bangladeshi infants during the first year of life

The growth in length and weight of 91 poor urban Bangladeshi infants was monitored at monthly intervals from birth to 1 year. At birth 18%, 22% and 8% were below -2.00 standard deviations of the National Center for Health Statistics (NCHS) height-for-age, weight-for-age and weight-for-height, respectively and at 1 year the percentages were 40%, 40% and 7%. Infant weights over the first 6 months associated positively with both mother's BMI and percentage body fat. Higher mean infant weights from 6 to 12 months were associated with both higher educational status of the mother and monthly family income and the latter two variables provided the best model for predicting weight velocity from birth to 12 months. Internal Z-scores, corrected for day of measurement, provided clear evidence of catch-up/catch-down over the first 6 months with heavier and longer babies at birth showing catch-down while lighter and shorter babies demonstrated catch-up. Infants' weights were almost three times more variable than lengths. Monthly incremental variability of both infant weight and length increased sharply from 6 to 12 months with weight showing significantly more variability. The correlations of birth weight and length with subsequent distances and monthly increment revealed that the first 6 months were dominated by catch-up and catch-down but during the latter half of the year the growth phenomena were influenced mainly by earlier intra-uterine or genetic effects.     

Inhibition of cigarette smoke-related lipophilic DNA adducts in rat tissues by dietary oltipraz

The present study investigated the effects of dietary oltipraz on cigarette smoke-related lipophilic DNA adduct formation. Female Sprague- Dawley rats were exposed daily to sidestream cigarette smoke in a whole- body exposure chamber 6 h/day for 4 consecutive weeks. One group of rats was maintained on control diet while another group received the same diet supplemented with either a low (167 p.p.m.) or high (500 p.p.m.) dose of oltipraz, starting 1 week prior to initiation of smoke exposure until the end of the experiment. Analysis of lipophilic DNA adducts by the nuclease P1-mediated 32P-post-labeling showed up to five smoke-related adducts. Adduct no. 5 predominated in both the lung and the heart while adduct nos 3 and 2 predominated in the trachea and bladder, respectively. Quantitative analysis revealed that the total adduct level was the highest in lungs (270+/-68 adducts/10(10) nucleotides), followed by trachea (196+/-48 adducts/10(10) nucleotides), heart (141+/-22 adducts/10(10) nucleotides) and bladder (85+/-16 adducts/10(10) nucleotides). High dose oltipraz treatment reduced the adduct levels in lungs and bladder by >60%, while the reduction in lungs in the low-dose group was approximately 35%. In trachea, the effect of low and high dietary oltipraz on smoke DNA adduction was equivocal, while smoke-related DNA adducts in the heart were minimally inhibited by high-dose oltipraz. In a repeat experiment that employed a 3-fold lower dose of cigarette smoke, oltipraz (500 p.p.m.) was found to inhibit the formation of DNA adducts in rat lungs and trachea by 80 and 65%, respectively. These data clearly demonstrate a high efficacy of oltipraz in inhibiting the formation of cigarette smoke-induced DNA adducts in the target tissues.      

Mutation of the p53 tumor suppressor gene in spontaneously occurring osteosarcomas of the dog

Inactivation of the p53 tumor suppressor gene has been implicated in the pathogenesis of numerous human cancers, including osteosarcomas. Appendicular osteosarcomas of the dog appear to be a good model for their human equivalent with regard to biologic behavior, epidemiology and histopathology. We individually screened exons 5-8 of the p53 gene for mutations in 15 canine appendicular osteosarcomas using 'Cold' SSCP to compare the role of this gene in human and canine osteosarcoma tumorigenesis. Seven of the tumors (47%) exhibited point mutations, with one tumor possessing two mutations within different exons. Of these, seven were missense mutations and the eighth was a 'silent' mutation potentially affecting the exon 6-7 splicing region. Five of the missense mutations were located in highly conserved regions IV and V, while another corresponded with the highly conserved codon 220 mutational hotspot located outside the conserved domains. The locations and types of mutations were nearly identical to those reported in human cancer. These findings provide strong evidence of the involvement of p53 mutations in the development of canine appendicular osteosarcomas. Canine osteosarcomas appear to be a promising model for their human equivalent on a clinical, pathologic, and molecular level.