Response of circadian locomotor activity and the proestrous luteinizing hormone surge to phase shifts of the light-dark cycle in the hamster

Female hamsters with regular 4 day estrous cycles were exposed to either a 3 hour phase advance or delay of the 14:10 light-dark (LD) cycle on the first, second or third day before proestrus. Blood samples were taken on proestrus to characterize the LH surge, and locomotor activity onset was recorded. Both the LH surge and activity onset phase delayed more quickly than they advanced, which can be explained by the free-running period of the hamster (longer than 24 hours). Higher estradiol levels were correlated with more rapid advances of activity onset.     

Quantity not composition of dietary fats represents the dominant contributor to experimental obesity: Relevance to human pathophysiology

Plant fats are low in saturated fats but high in unsaturated fats compared to animal fats, and are supposedly less obesogenic. This study compared the obesogenic effects of plant and animal derived fatty diets in Wistar rats. Rats of each gender were divided into three dietary (standard chow (SC), high fat diet rich in animal fat (HFDaf) and a high fat diet rich in plant fat (HFDpf)) groups of ten each and fed for 17 weeks. Anthropometric, Adiposity and nutritive variables were assessed using standard methods. Comparing HFDpf to HFDaf: Abdominal circumference (AC),initial feed intaken (IFI), final feed intake(FFI), final body weight (FBW), white adipose tissue (WAT) were increased but brown adipose tissue (BAT) decreased in male rats fed with HFDpf; also, there were increased body length, IFI, FFI but decreased AC, FBW, BAT in female rats fed with HFDpf. Comparing male to female rats: Thoracic circumference, IFI, FFI, energy intake were increased while Adiposity index decreased across diet groups in male rats; the AC, FBW increased while WAT, BAT decreased in HFDpf fed group, also, BAT was increased but AC, FBW decreased in HFDaf fed group in male rats. Palatability and high feed efficiency of consumed diets were more associated with obesogenic risk than just the level of saturation. Therefore, Obesogenic effects of fatty diets in both genders is more dependent on the quantity (amount) of fatty diet consumed than the dietary fat composition alone.     

The production of fatty acid modifying enzyme (FAME) and lipase by various staphylococcal species.

Eighty-six strains encompassing 11 species of coagulase-negative staphylococci were examined for the production of fatty acid modifying enzyme (FAME) and lipase. Staphylococcus schleiferi and S. saprophyticus most closely resembled S. aureus in that 80% of the strains produced both enzymes. In contrast, no strains of S. lugdunensis and S. haemolyticus tested produced these enzymes. S. simulans was unusual in that eight of 10 strains produced FAME, but only one produced lipase. Among the other species the proportion of strains producing both enzymes ranged from 10 to 60%. Generally there was a strong correlation between FAME and lipase production.     

Maternal behavior predicts infant cortisol recovery from a mild everyday stressor

BACKGROUND: In the very first years of life, parenting is considered to be important for the regulation of the infant's emotional and physiological states. In the present study, three-month-old infants' cortisol responses (reactivity and recovery) to a mild everyday stressor, namely being taken out of the bath, were examined in relation to the quality of maternal behavior. It was hypothesized that a higher quality of maternal behavior towards the infant predicted lower cortisol reactivity as well as a better recovery from the reaction. METHOD: The participants were 64 infants (34 boys and 30 girls) and their mothers. Maternal behavior (sensitivity and cooperation) towards the infant during the bathing routine was rated from videotapes. Salivary cortisol was obtained from the infants three times: before the bathing routine (T1), and 25 minutes (T2) and 40 minutes (T3) after the infants were taken out of the bath. RESULTS: The infants reacted with a significant increase in cortisol to the stressor (from 6.8 nmol/l to 9.9 nmol/l), and regression analysis showed that the higher the quality of maternal behavior the better the cortisol recovery from the stressor. CONCLUSION: Our findings indicate the potential importance of social processes for physiological recovery from everyday stressful situations in infants.     

Autosomal recessive retinitis pigmentosa and cone-rod dystrophy caused by splice site mutations in the Stargardt's disease gene ABCR

Ophthalmological and molecular genetic studies were performed in a consanguineous family with individuals showing either retinitis pigmentosa (RP) or cone-rod dystrophy (CRD). Assuming pseudodominant (recessive) inheritance of allelic defects, linkage analysis positioned the causal gene at 1p21-p13 (lod score 4.22), a genomic segment known to harbor the ABCR gene involved in Stargardt's disease (STGD) and age- related macular degeneration (AMD). We completed the exon-intron structure of the ABCR gene and detected a severe homozygous 5[prime] splice site mutation, IVS30+1G->T, in the four RP patients. The five CRD patients in this family are compound heterozygotes for the IVS30+1G- >T mutation and a 5[prime] splice site mutation in intron 40 (IVS40+5G- >A). Both splice site mutations were found heterozygously in two unrelated STGD patients, but not in 100 control individuals. In these patients the second mutation was either a missense mutation or unknown. Since thus far no STGD patients have been reported to carry two ABCR null alleles and taking into account that the RP phenotype is more severe than the STGD phenotype, we hypothesize that the intron 30 splice site mutation represents a true null allele. Since the intron 30 mutation is found heterozygously in the CRD patients, the IVS40+5G->A mutation probably renders the exon 40 5[prime] splice site partially functional. These results show that mutations in the ABCR gene not only result in STGD and AMD, but can also cause autosomal recessive RP and CRD. Since the heterozygote frequency for ABCR mutations is estimated at 0.02, mutations in ABCR might be an important cause of autosomal recessive and sporadic forms of RP and CRD.      

人头颈部骨骼肌干细胞的分离培养及生长特性研究

目的 体外建立人骨骼肌干细胞的纯化及鉴定方法,并对所分离干细胞的生物学特性进行分析研究.方法 分离人头颈部正常骨骼肌组织,采用无血清培养基,悬浮状态培养技术得到人骨骼肌干细胞,体外扩增并观察生长特性.细胞免疫荧光染色和反转录聚合酶链反应(RT-PCR)技术鉴定标记物的表达情况,单细胞克隆观察单个细胞生长特性.将分离来的细胞分别转移至采用成平滑肌、成脂、成骨诱导培养基内,观察细胞的生长分化特性,并通过特异性染色予以鉴定.结果 悬浮培养条件下,倒置相差显微镜观察示骨骼肌干细胞在培养基内不断增殖形成细胞球.免疫荧光染色示细胞球表达卫星细胞的标记物Pax7及ALDH1,贴壁生长扩增传代后表达肌原细胞标记物Myod及Desmin;RT-PCR检测示表达干细胞标记物Oct3/4,Nanog,Sox2和Pax7;单克隆形成实验显示单个细胞可在悬浮状态下形成新的细胞克隆.骨骼肌细胞在体外可以诱导分化为平滑肌、骨和脂肪细胞.结论 在体外可以成功分离、纯化和扩增人骨骼肌干细胞,其具有干细胞的自我更新和多向分化潜能.     

Overexpression of Nerve Growth Factor in Skin Increases Sensory Neuron Size and Modulates Trk Receptor Expression

Sensory neuron development and differentiation is dependent on a family of growth factors known as neurotrophins. Neurotrophins modulate neuron development via trk tyrosine kinase receptor proteins trkA, trkB and trkC. To determine how elevated levels of a target-derived neurotrophin might affect neuronal differentiation, we analysed trk expression in the trigeminal ganglion of transgenic mice that overexpressed nerve growth factor (NGF) in the skin. increased levels of NGF caused a five-fold increase in neurons expressing trkA mRNA and a two-fold increase in neurons expressing trkC. In control mice, cell size distributions of neuronal subpopulations expressing each trk mRNA showed the three subpopulations distributed over a narrow, overlapping range. In contrast, cell size distribution in NGF-transgenic mice was significantly divergent due in large part to hypertrophy of trkA neurons and, to a lesser extent, trkC neurons. In addition, we examined neurons that bound the isolectin B4 from Bandeiraea simplicifolia (BS-IB4) because most of these neurons do not express any trk receptor in the adult. There was a significant increase in the size of BS-IB4–positive neurons in transgenic mice; however, there was no increase in their number. These studies indicate that an increased level of target-derived NGF affects the development of sensory neurons that in the adult express trkA or trkC, as well as neurons that do not express trk receptors.