Measurement of 7-dehydrocholesterol and cholesterol in hair can be used in the diagnosis of Smith-Lemli-Opitz syndrome

7-dehydrocholesterol (7-DHC) and cholesterol (CHOL) are biomarkers of Smith-Lemli-Opitz Syndrome (SLOS), a congenital autosomal recessive disorder characterized by elevated 7-DHC level in patients. Hair samples have been shown to have great diagnostic and research value, which has long been neglected in the SLOS field. In this study, we sought to investigate the feasibility of using hair for SLOS diagnosis. In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), hair samples were completely pulverized and extracted by micro-pulverized extraction in alkaline solution or in n-hexane. After microwave-assisted derivatization with N,O-Bis(trimethylsilyl)trifluoroacetamide, the analytes were measured by GC-MS. We found that the limits of determination for 7-DHC and CHOL were 10 ng/mg and 8 ng/mg, respectively. In addition, good linearity was obtained in the range of 50–4000 ng/mg and 30–6000 ng/mg for 7-DHC and CHOL, respectively, which fully meets the requirement for SLOS diagnosis and related research. Finally, by applying the proposed method to real hair samples collected from 14 healthy infants and two suspected SLOS patients, we confirmed the feasibility of hair analysis as a diagnostic tool for SLOS. In conclusion, we present an optimized and validated analytical method for the simultaneous determination of two SLOS biomarkers using human hair.     

The protective effects of MSC‐EXO against pulmonary hypertension through regulating Wnt5a/BMP signalling pathway

The aim of the study was to explore the mechanism of mesenchymal stem cell‐derived exosomes (MSC‐EXO) to protect against experimentally induced pulmonary hypertension (PH). Monocrotaline (MCT)‐induced rat model of PH was successfully established by a single intraperitoneal injection of 50 mg/kg MCT, 3 weeks later the animals were treated with MSC‐EXO via tail vein injection. Post‐operation, our results showed that MSC‐EXO could significantly reduce right ventricular systolic pressure (RVSP) and the right ventricular hypertrophy index, attenuate pulmonary vascular remodelling and lung fibrosis in vivo. In vitro experiment, the hypoxia models of pulmonary artery endothelial cell (PAEC) and pulmonary vascular smooth muscle cell (PASMC) were used. We found that the expression levels of Wnt5a, Wnt11, BMPR2, BMP4 and BMP9 were increased, but β‐catenin, cyclin D1 and TGF‐β1 were decreased in MSC‐EXO group as compared with MCT or hypoxia group in vivo or vitro. However, these increased could be blocked when cells were transfected with Wnt5a siRNA in vitro. Taken together, these results suggested that the mechanism of MSC‐EXO to prevent PH vascular remodelling may be via regulation of Wnt5a/BMP signalling pathway.     

Pre‐copulation intervals,copulation frequencies,and initial progeny sex ratios in two biotypes of whitefly,Bemisia tabaci

The whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is a species complex, and its systematic classification requires controlled crossing experiments among its genetic groups. Accurate information on pre‐copulation intervals, copulation frequencies, and initial frequency of egg fertilization of newly emerged adults is critical for designing procedures for collecting the virgin adults necessary for these experiments. In the literature, considerable variation is reported between B. tabaci populations, with respect to the length of the pre‐copulation interval and the initial frequency of egg fertilization. Here, we used a video‐recording method to observe continuously the copulation behaviour of the Mediterranean/Asia Minor/Africa (B biotype) and the Asia II (ZHJ1 biotype) groups of B. tabaci. We also recorded the initial frequency of egg fertilization, as determined by the sex of the progeny. When adults were caged in female–male pairs on leaves of cotton plants, the earliest copulation events occurred 2–6 h after emergence; at 12 h after emergence 56–84% of the females had copulated at least once, and nearly all (92–100%) had copulated at least once by 36 h after emergence. Both females and males copulated repeatedly. Approximately 80 and 20% of copulation events occurred during the photophase and scotophase, respectively. By 72 h post‐emergence, the females of the B and ZHJ1 biotypes had copulated on average 6.1 and 3.9 times, respectively. When adults were caged in groups on plants 1–13 h after emergence, 30–35% of the eggs deposited during this period were fertilized, and approximately 90% of females were fertilized by the end of the 13 h. Although timing of copulation differed in detail between the two genetic groups, the results demonstrate that B. tabaci adults can start to copulate as early as 2–6 h post‐emergence and the majority of females can become fertilized on the day that they emerge.     

Ca~(++)促进大麦根K~+吸收的过程分析

吸收溶液中CaCl_2促进了大麦根K~+净吸收,Ca~(++)本身对H~+分泌无影响,Cl~-减少了H~+净分泌量。 含有~(86)Rb的大麦根在1m mol/L KCl溶液中发生~(86)Rb外流,在H_2O、1m mol/L NaCl或0.5 m mol/L CaCl_2中没有明显外流。VO_4~(3-)、NaN_3和4℃低温均可以减少根段在1m mol/L KCl溶液中的~(86)Rb外流量。Ca~(++)抑制K~+(~(86)Rb~+)的外流,EDTA加剧外流,Ca~(++)可以逆转EDTA的效应。 Ca~(++)抑制K~+(~(86)Rb)外流和促进K~+净吸收的趋势相吻合。K~+吸收的通量分析结果表明,Ca~(++)抑制K~+通过质膜的外流,促进K~+由细胞质向液泡中转运,而不影响K~+通过质膜的内流速率。     

Changes in the timing of births in Melbourne, Australia

2 10-year marriage cohorts from 2 surveys of married women in Melbourne were compared on their timing of the 1st and 2nd births. The results showed that women who were married in the early 1970s were much more likely to delay their first birth until about the 3rd or 4th year of marriage compared with women who married in the 1960s. This tendency to delay the 1st birth was probably aided by effective contraception, as it coincided with widespread use of the oral contraceptive. There was no difference in the timing of the 2nd birth in relation th the 1st birth between the 2 marriage cohorts. Women who delayed childbearing also preferred smaller families. Indeed, the increase in the % of women delaying childbearing appears to be synonymous with the trend toward the two-child family. Altough the number of married women in the labor force increased significantly from the early to the later cohort, a desire to work was not usually cited as the reason for delaying childbearing. Rather, economic reasons were most frequently mentioned for delaying childbearing.     

Simulation of gas transport due to cardiogenic oscillations

We simulated gas transport due to cardiogenic oscillations (CO) using a model developed to quantify the gas mixing due to high-frequency ventilation (16). The basic components of the model are 1) gas mixing by augmented transport, 2) symmetrical lung morphometry, and 3) a Lagrangian (moving) reference frame. The theoretical predictions of the model are in general agreement with published experimental studies that have examined the effect of CO on the nitrogen concentration obtained by intrapulmonary gas sampling and the effect of CO on regional and total anatomical dead space. Further, the model predicts that augmentation of gas transport due to CO is less, nearer to the alveolar regions of the lung, and that the effect of CO during normal tidal breathing is negligible, but that CO may contribute up to approximately 10% of the alveolar ventilation in patients with severe hypoventilation. The agreement between experimental and theoretical results suggests that it may not be necessary to invoke gas transport mechanisms specific to an asymmetrical bronchial tree to explain the major proportion of gas transport due to CO.     

表面活性剂和Ca~(++)对大麦根质膜透性的作用

阳离子型表面活性剂(CTMA)以低于CMC的浓度、非离子型表面活性剂(Triton-X-100)以高于CMC的浓度引起大麦离体根K~+及可溶性糖的外流,并有浓度效应。5℃时表面活性剂引起溶质外流,CTMA预处理10 min后,Ca~(++)无抑制作用。Ca~(++)与 Triton-X-100同时处理大麦根促进溶质外流。Mg~(++)、Mn~(++)对CTMA及Triton-X-100引起溶质外流的效应与Ca~(++)的相类似,但不如Ca~(++)有效。     

Hypermagnesaemia in Presence of Magnesium Depletion in Acute-on-chronic Renal Failure

A patient with renal failure developed hypermagnesaemia, with confusion, drowsiness, and dysarthria. Nevertheless, the dietary magnesium content was low, and investigation showed actual intracellular depletion of magnesium. The cause of this state is not known, though it is presumably connected with a failure to maintain the normal concentration gradient of magnesium across the cell wall. The clinical state and the serum magnesium level returned to normal after treatment with calcium gluconate.     

Causes of Hypertension in the Young

Of 127 hypertensive patients aged 12 to 40 investigated by intravenous pyelography, abdominal aortography, and renal biopsy an underlying cause was found in 57%. The proportion with secondary hypertension was higher in young patients and in those with severe hypertension. Primary arteritis of the aorta was an important cause of renovascular hypertension in an Asian population.