重组人白血病抑制因子对体外移植前鼠胚发育的影响

目的：观察重组人白血病抑制因子（rhLIF)对体外移植前鼠胚发育的影响。方法：将36只小鼠随机分成3组,每组12只。组I（体内对照）小鼠注射人绒毛膜促性腺激素（hCG)116-120h后处死,组Ⅱ及组Ⅲ（体外对照）小鼠注射hCG44-48h后处死,收集组Ⅱ及组Ⅲ的2细胞期鼠胚,组Ⅱ的鼠胚用人输卵管液（HTF）＋10％人血清培养,组Ⅲ的鼠胚用HTF＋10％人血清＋rhLIF(1000U/ml）培养,观察并记录各细胞期鼠胚发育的数目。结果：（1）组Ⅱ和组Ⅲ发育到4细胞期、8细胞期、桑椹胚阶段的鼠胚百分率（分别为93．4％、87．7％、75．0％和94．5％、91．2％、85．4％）相似,差异无显著性（P＞0．05）。（2）组Ⅱ发育到囊胚期、扩张囊胚期和孵出期的鼠胚百分率低于组Ⅲ（分别为48．1％、32．1％、18．4％和82．3％、59．7％、36．3％）,差异有显著性（P＜0．05）。（3）组I和组Ⅲ发育到囊胚期的鼠胚百分率（分别为86．0％和82．3％）相比,差异无显著性（P＞0．05）。结论：rhLIF对鼠胚的早期发育没有显著影响,但能促进移植前晚期鼠胚的生长、分化和孵出。     

Early prophylactic inhaled beclomethasone in infants less than 1250 g for the prevention of chronic lung disease

OBJECTIVE:

Inflammation plays an important role in the development of chronic lung disease (CLD), which has become a major cause of morbidity in surviving infants less than 1250 g at birth. The authors hypothesized that the progression of this inflammation and, therefore, the establishment of CLD would be decreased with the use of early prophylactic inhaled corticosteroids. Short, and long term respiratory and neurodevelopmental outcomes were also examined.

DESIGN:

A double-blind, randomized placebo controlled trial.

SETTING:

Level-III neonatal intensive care unit.

POPULATION STUDIED:

Sixty infants less than 1250 g at birth, diagnosed with respiratory distress syndrome and requiring ventilatory support at 72 h of age were enrolled in the study.

INTERVENTION:

Infants enrolled received either placebo or beclomethasone diproprionate by a metered dose inhaler, which was used in-line with the ventilator circuit while the infant was ventilated and then via a spacer until 28 days of age.

RESULTS:

Thirty infants were given beclomethasone and 30 were given placebo. There were two deaths in each group. Among the surviving infants, the frequency of moderate-to-severe CLD was 17% in each study group. Mean time to extubation was not different for beclomethasone compared with placebo at 16.4 and 12.5 days (P=0.12), respectively. The requirement for intravenous corticosteroids was lower in the beclomethasone-treated group (RR 0.67, 95% CI 0.43 to 1.04), although this difference was not statistically significant. The incidence of growth failure, infection and intraventricular hemmorhage did not differ between the two groups. Long term outcomes were not different with respect to the incidence of respiratory re-admissions, cerebral palsy, developmental delay, blindness or deafness.

CONCLUSIONS:

Early treatment with inhaled beclomethasone diproprionate did not reduce the incidence of CLD or decrease the duration of mechanical ventilation. The decrease in intravenous corticosteroid use was not statistically significant. Long term outcome was not affected.     

Intra-individual difference between recumbent length and stature among growing children

Objective Difference between recumbent length and stature in an individual has been observed by many researchers in the past in European and American populations. The present study explores the intra-individual differences between recumbent length and stature (R.L.-Stature).Methods: A sample of 920 school going children was considered in Chandigarh city.Result: These differences are found to be statistically significant and have definite relationship with age and weight of the children. The mean difference between recumbent length and stature is found to be greater in males than in females between 5 through 10 years and between 15 through 18 years of age. However, between 10 through 15 years, it was greater in females than in males.Conclusion: This was largely due to the fact that adolescent spurt in stature preceded by two to three years in girls than that of boys. This difference was also found to be significantly correlated with age, weight and stature in both the sexes. Two regression equations are derived separately for the two sexes, from which, one can convert recumbent length into stature and vice-versa     

Analysis of medical students' use of web-based resources for a gross anatomy and embryology course

An extensive Web site supporting our gross anatomy and embryology course, which includes various course management pages as well as online lectures, has been in use for the past 2 years. To determine how this Web site is being used by students, we examined server log files to track access to each of the Web pages on the site. Using this data, along with student responses on a course evaluation, we have been able to quantitatively characterize Web site use and gain some insight into students' perception of the site. This analysis showed that all of the resources available online, including course management information, exam reviews, online lectures, and dissection guides were heavily used and deemed useful by students. Despite universal computer ownership and Internet access from home, most use of the Web site was from on-campus computer labs, especially for lectures with audio streams. This was probably due to the limited bandwidth of off-campus connections. Data on the day of the week and time of the day of access showed peak activity at expected times, but also significant activity at all hours, as students took full advantage of 'access on demand.' This on-demand nature of the Web was also evident in students' viewing of lectures in short sessions rather than in one sitting. Online lectures were used regularly by a majority of students both before and after corresponding class sessions, however, this was not the preferred venue for all students. Although the flexibility of Web-based resources accommodates students' varying study habits, the alternative of traditional print material and live lectures should not be abandoned lightly.     

Determinants of linear growth and predictors of severe stunting during infancy in rural Malawi

Stunting is common among children under 5 y of age in sub-Saharan Africa. Several risk factors have been associated with poor growth but few studies have prospectively addressed the development of linear growth faltering and stunting during the first year of life. The present study was designed to analyse typical growth among rural Malawian infants, focusing particularly on the impact of birth size, adherence to feeding guidelines and morbidity in the development of severe stunting during infancy. A community-based cohort of 613 singleton newborns was prospectively followed by monthly home visits. Data were collected on the children's socioeconomic background, maternal size and weight gain during pregnancy, birth events, morbidity, breastfeeding and complementary feeding, growth and mortality. Univariate and multivariate analyses were used to determine associations between predictor variables and poor linear growth. The proportions of stunted infants (Height-for-age Z-score 3 32) at 3, 6 and 9 mo of age were 27%, 51%, and 63%, respectively. At 1 y of age, over two-thirds (71%) of the infants were at least moderately (HAZ 3 32) and 31% severely stunted (HAZ 3 33). Conclusion: The strongest predictor of severe stunting at 12 mo of age was small birth size. Other variables independently associated with this outcome included inappropriate complementary feeding, high morbidity, maternal short stature, male gender, and home delivery. Faltering of linear growth started soon after birth and continued throughout infancy. Interventions increasing birth size could have a significant role in the prevention of early childhood stunting. The ideal strategy should also emphasize the importance of appropriate infant feeding and decreasing the number of illness episodes amongst the infants.     

Swedish population-based longitudinal reference values from birth to 18 years of age for height,weight and head circumference

This study aimed to update growth reference values for height, weight and head circumference in order to reflect the changes in body size in the Swedish population during the past two decades. The data came from a large longitudinal growth study on 3650 full-term healthy Swedish children who were born between 1973 and 1975. All of these 1801 girls and 1849 boys had longitudinal data for height and weight from birth to final height. Comparison with previous Swedish growth reference values based on children born between 1955 and 1958 revealed that there have been secular changes in body size. For instance, at 18 y of age, the updated height and weight reference values are 180.4 cm for males and 167.7 cm for females, i.e. 1.9 cm taller and 5.7 kg heavier for males and 2.3 cm taller and 3.4 kg heavier for females compared with the previous reference values.

Conclusion : These new growth reference values provide current national standards for growth monitoring and evaluation since the year 2000.     

Psychological functioning in boys of short stature: effects of different levels of growth hormone secretion

Aim: To examine the relationship between growth hormone (GH) and psychological functioning, especially self-perception and well-being, in 60 prepubertal boys of short stature with a wide range of GH levels. Methods: A comparison was made of the well-being and self-perception of children with GH insufficiency, children with idiopathic short stature (ISS), a normative sample and healthy boys with normal stature. Results: Children with GH insufficiency had a more negative perception of their own physical appearance than the normative sample. They perceived themselves as more alert but also more inhibited than both the children with ISS and the healthy boys with normal stature. In comparison with the healthy boys with normal stature they perceived themselves as having more stability. The parents of the boys with GH insufficiency also perceived their children as being more stable compared with how the parents of boys with ISS perceived their children. To elucidate the effects of GH on psychological functioning a multiple regression analysis was performed.

Conclusion: The lower the levels of GH the more inhibited were the boys of short stature, as perceived both by themselves and by their parents. The boys with GH insufficiency had a more negative perception of their physical appearance than the normative sample.     

Cloning and characterisation of the GH gene from the common dolphin (Delphinus delphis)

The sequence of growth hormone (GH) is generally strongly conserved in mammals, but episodes of rapid change occurred during the evolution of primates and artiodactyls, when the rate of GH evolution apparently increased at least 50-fold. As a result, the sequences of human and ruminant GHs differ substantially from those of other non-primate GHs. Recent molecular studies have suggested that cetaceans are closely related to artiodactyls and may be deeply nested within the artiodactyl phylogenetic tree. To extend the knowledge of GH in Cetartiodactyla (Artiodactyla plus Cetacea), we have cloned and characterised a single GH gene from the common dolphin (Delphinus delphis), using genomic DNA and a polymerase chain reaction technique. As in other mammals, the dolphin GH gene comprises five exons and four introns. The deduced sequence for the mature dolphin GH differs from that of pig at two residues only, showing that the apparent burst of rapid evolution of GH occurred largely after the separation of cetaceans and ruminants.     

Small changes in whole-body corticosterone content affect larval Rana pipiens fitness components

In amphibians, large changes in tissue corticosterone content (caused by treatment with large doses of hormone) alter tadpole growth and development, but the effects of smaller changes on growth, development, behavior, and morphology are unknown. In the current study, we exposed pre-metamorphic Rana pipiens tadpoles to moderate doses (62 and 125 nM) of exogenous corticosterone by adding it to the rearing water. We then analyzed effects on growth, development, behavior, morphology, and the endogenous corticosterone response to exogenous adrenocorticotropic releasing hormone (ACTH). A 50% elevation in whole-body corticosterone content was associated with slowed growth and development, increased tail muscle depth, and a diminished corticosterone response to ACTH. Behavior was unaffected by corticosterone administration. Treatment with the corticoid synthesis inhibitor metyrapone (MTP) reduced whole-body corticosterone content by 50% and was associated with increased size at metamorphosis but no change in time to metamorphosis. Our findings support the hypothesis that corticoids can mediate growth, developmental, and morphological responses of tadpoles to changing environmental conditions. Our results also demonstrate that even small changes in corticosterone content can have important implications for amphibian fitness.     

Long-term linear growth of children with severe steroid-responsive nephrotic syndrome

The present study was designed to evaluate the risk of permanent linear growth impairment in a selected group of 42 children with steroid-dependent nephrotic syndrome (SDNS) and 14 children with frequently relapsing nephrotic syndrome (FRNS). Longitudinal height measurements were available in all patients from the onset of the disease for a mean follow-up of 11.7±3.5 years. During the prepubertal period, patients lost 0.49±0.6 height SD score (HtSDS) (P<0.001). Twenty-three patients have reached their final height with an average loss of 0.92±0.8 HtSDS from the onset of their disease (P<0.001) and 0.68±0.7 from their target HtSDS (P<0.001). The pubertal growth spurt was mildly delayed in male but not female patients. Steroid therapy, calculated as the mean duration of prednisone (PDN) treatment or as the average cumulative PDN dose, was the only predictor of poor growth evolution. Partial catch-up growth occurred after PDN withdrawal. Children with early onset NS and adolescent patients, who were still receiving PDN after the age of 9 years in girls and 11 years in boys, were at higher risk for HtSDS loss. In conclusion, children with severe steroid-responsive NS are at risk of permanent growth retardation secondary to prolonged courses of steroid treatment.