Muscle-specific expression of the smyd1 gene is controlled by its 5.3-kb promoter and 5'-flanking sequence in zebrafish embryos.

Zebrafish SmyD1 is a SET and MYND domain-containing protein that plays an important role in myofiber maturation and muscle contraction. SmyD1 is required for myofibril organization and sarcomere assembly during myofiber maturation. Whole-mount in situ hybridization revealed that smyd1 mRNAs are specifically expressed in skeletal and cardiac muscles in zebrafish embryos. However, it is unknown if smyd1 is expressed in other striated muscles, such as cranial and fin muscles, and moreover, the regulatory elements required for its muscle-specific expression. We report here the analyses of smyd1 expression using smyd1-gfp transgenic zebrafish. smyd1-gfp transgenic zebrafish were generated using the 5.3-kb smyd1 promoter and its 5'-flanking sequence. GFP expression was found in the skeletal and cardiac muscles of smyd1-gfp transgenic embryos. GFP expression appeared stronger in slow muscles than fast muscles in transgenic zebrafish larvae. In addition, GFP expression was also detected in cranial and fin muscles of smyd1-gfp transgenic zebrafish larvae. In situ hybridization confirmed smyd1 mRNA expression in these tissues, suggesting that the expression of the smyd1-gfp transgene recapitulated that of the endogenous smyd1 gene. Deletion analysis revealed that the 0.5-kb sequence in the proximal promoter of smyd1 was essential for its muscle specificity. Together, these data indicate that smyd1 is specifically expressed in most, if not all, striated muscles, and the muscle specificity is controlled by the 5.3-kb promoter and flanking sequences.     

纳曲酮对移植排异反应的抑制作用

以小鼠心肌组织异位移植和混合淋巴细胞反应为整体和离体模型，观察了阿片受体阻断剂纳曲酮对移植排异反应的影响。结果显示：给动物从术前开始腹腔注射纳曲酮共１０天（每日二次，每次５ｍｇ／ｋｇ）可明显延长移植心肌组织的存活时间；加入纳曲酮（１０－４～１０－８ｍｏｌ／Ｌ）对混合淋巴细胞反应有抑制作用并呈量效关系。同时还观察到，给正常小鼠腹腔注射纳曲酮３天以上，可引起动物脾细胞由ＣｏｎＡ诱导的淋巴细胞转化反应受抑制。以上结果说明纳曲酮可抑制移植排异反应，此作用有可能是通过阻断内源性阿片肽所致。     

The vitamin D content of fortified milk and infant formula.

BACKGROUND. The fortification of milk and infant formula with vitamin D has had an important role in eliminating rickets in children and osteomalacia in adults. A recent outbreak of vitamin D intoxication caused by drinking milk fortified with excess vitamin D has led to questions about the level of vitamin D in milk from other producers. METHODS. We used high-performance liquid chromatography to measure vitamin D in samples of 13 brands of milk with various fat contents and 5 brands of infant formula purchased at random from local supermarkets in five Eastern states. RESULTS. Only 12 (29 percent) of the 42 samples of the 13 brands of milk and none of the 10 samples of the 5 brands of infant formula contained 80 to 120 percent of the amount of vitamin D stated on the label. Twenty-six of the 42 milk samples (62 percent) contained less than 80 percent of the amount claimed on the label. No vitamin D was detected in 3 of the 14 samples of skim milk tested (lower limit of assay, 4.7 IU per quart [5.0 IU per liter]). One milk sample labeled as containing vitamin D2 (ergocalciferol) contained vitamin D3 (cholecalciferol). Seven of the 10 samples of infant formula contained more than 200 percent of the amount stated on the label; the sample with the highest concentration contained 419 percent of the stated amount. None of the samples of infant formula contained less than the amount stated. CONCLUSIONS. Milk and infant-formula preparations rarely contain the amount of vitamin D stated on the label and may be either underfortified or overfortified. Since both underfortification and overfortification are hazardous, better monitoring of the fortification process is needed.     

家兔腓肠肌在电刺激下力学行为的实验研究

目的 获得肌肉收缩力学特性与其电生理特性间的实验关系。方法 用肌电仪发出不同波宽、不同强度的脉冲电流，对家兔的胫神经进行刺激，记录其复合动作电位及收缩力。结果 得到了收缩力与各种肌电信号的实验关系曲线。结论收缩力与刺激电流之间呈正相关关系、与复合动作电位幅值(CAMP)之间呈线性关系，且收缩力与肌电积分值之间也呈较好的线性关系。     

V3 sequence analysis and biological characterization of HIV-1 isolates from asymptomatic and early symptomatic Tanzanian individuals

The aim of this study was to determine HIV-1 V3 sequences, in vitro biological characteristics and co-receptor usage of virus isolates from Tanzania. Virus was isolated from 14 of 17 samples investigated. Four of the isolates induced syncytia in MT-2 cells and used the CXCR4 co-receptor, while the remaining 10 isolates used the CCR5 co-receptor characteristic of non-MT-2 tropic viruses. One of the four MT-2 tropic isolates also used the CCR5 and CCR3 co-receptors. Proviral DNA was detected in all 14 isolates and PCR products were subjected to DNA sequencing. Unambiguous V3 amino acid sequences were obtained from 11 amplificates. Phylogenetic analysis indicated that these sequences were divergent and clustered in HIV-1 subtypes A, C or D. Sequences from the viruses that induced syncytia in MT-2 cells presented characteristic V3 phenotype-associated amino acids. Results of co-receptor analysis are in concordance with the isolate phenotype as determined by replication and induction of syncytia in MT-2 cells. The considerable diversity illustrated by a limited number of isolates from Tanzania is in accordance with reports from other regions of Africa.     

Diversity of Hepatitis G Virus within a Single Infected Individual

The extent of population diversity among GB virus C (GBV-C)/hepatitis G virus (HGV) within a persistently infected individual (Iw) was investigated by sequence analysis of multiple clones generated from polymerase chain reaction (PCR)-amplified products of cDNA analogous to fragments of 5 non-coding region (5NC), envelope region 1/2 (E1/E2) and non-structural region 3 (NS3) of viral genome. Although nucleotide substitutions were more common in coding regions than in the 5NC region, there was no region corresponding to the hypervariable region of hepatitis C virus in the E1/E2 region. Transition substitution exceeded transversion by 7 to 12-fold, and 79.4% of substitutions were synonymous. This bias against substitutions producing amino acid replacements and the use of Pfu DNA polymerase with an error rate 10 times lower than the observed frequency of substitution, suggests that most substitutions were not artefactual. This data suggests that individual genomes of HGV within an infected individual may differ from each other at 0.23–0.84% nucleotide position and at 0.42–0.61% amino acid position.     

白血病骨髓瘤单抗对白血病细胞株细胞内环核苷酸的影响

本文应用放射免疫测定法,检测了单克隆抗体(λ-44-5-15,λ26-4-15,SMb,OKT10和抗B)作用于相应白血病瘤细胞后细胞内cAMP、cGMP的含量变化。结果发现:抗原、抗体比例在80∶1时经McAb作用16～24h后,瘤细胞内cAMP含量明显高于对照组,cGMP含量明显低于对照组(P<0002-0001)。从而提示:McAb可通过对细胞膜作用,调控细胞内cAMP和cGMP的水平。本文还对McAb作用浓度及作用时间进行了探讨。     

Undocumented Migrants Reintroducing COVID-19, Yunnan Province,China

To limit the spread of severe acute respiratory syndrome coronavirus 2, the government of China has been monitoring infected travelers and minimizing cold-chain contamination. However, other factors might contribute to recurring outbreaks. We analyze the role of undocumented migrants as potential transmitters of severe acute respiratory syndrome coronavirus 2 in China.     

板层角膜移植联合球结膜唇粘膜移植治疗烧伤重症睑球粘连

目的 观察角膜移植治疗烧伤后睑球粘连的效果。方法 应用板层角膜移植联合自体球结膜、唇粘膜移植术治疗28例（29眼）重症睑球粘连,将角结膜假性胬肉分离至穹窿部,保留板层角膜及胬肉上皮层并反转作为睑结膜或移植粘膜作为睑膜,用新鲜板层角膜作供体更替浑浊角膜,用同侧或对侧眼球结膜修补巩膜表面结膜创面。结果 一次手术者25眼,二次手术3眼,三次手术1眼,治愈20眼,明显好转6眼,复发3眼。结论 板层角膜移植联合球结膜、唇粘膜 后重症睑球粘连是一种良好的手术方法。