[The distribution of musk and river deer in local chronicles in Guizhou]

Some information and records about musk (She, ) and river deer (Zhang, /) can be found in local chronicles or documents in Guizhou. They were taken as the same species in terms of a medicinal animal. The records for their living areas in Guizhou were neither clear nor in detail in the Ming Dynasty, but were specific in the Qing Dynasty and more concise in the period of the Republic of China. The living areas for musk and river deer reduced from the Ming Dynasty to the Republic of China. Such change was believed to be the result of the natural environment and the social factors as well, such as the reclamation of mountain areas in Guizhou, the reduction of forests, and the demand and resulting exorbitant prices that led to excessive hunting.

First national record of Microhylahmongorum Hoang, Nguyen, Phan, Pham, Ninh, Wang, Jiang, Ziegler and Nguyen, 2022 (Anura, Microhylidae, Microhyla) in China

Background

To date, 10 species of the genus Microhyla have been recorded in China, of which six were distributed in Yunnan Province. Microhylahmongorum Hoang, Nguyen, Phan, Pham, Ninh, Wang, Jiang, Ziegler, and Nguyen, 2022 was also speculated to be distributed in Xishuangbana, Yunnan Province, China. However, there is no evidence of documentation of M.hmongorum.

New information

We report the first country record of Microhylahmongorum, based on specimens collected from Yunnan border region. Morphologically, the specimen was consistent with the original descriptions of M.hmongorum. Phylogenetically, the sequences of the specimens from China clustered with the sequence of type specimens of M.hmongorum from Vietnam, with uncorrected pairwise distances of 0.9% at the 16S gene fragment analysed. Therefore, we report M.hmongorum as a new record species in China.

DNA barcoding of Chinese snakes reveals hidden diversity and conservation needs

DNA barcoding has greatly facilitated studies of taxonomy, biodiversity, biological conservation, and ecology. Here, we establish a reliable DNA barcoding library for Chinese snakes, unveiling hidden diversity with implications for taxonomy, and provide a standardized tool for conservation management. Our comprehensive study includes 1638 cytochrome c oxidase subunit I (COI) sequences from Chinese snakes that correspond to 17 families, 65 genera, 228 named species (80.6% of named species) and 36 candidate species. A barcode gap analysis reveals gaps, where all nearest neighbour distances exceed maximum intraspecific distances, in 217 named species and all candidate species. Three species-delimitation methods (ABGD, sGMYC, and sPTP) recover 320 operational taxonomic units (OTUs), of which 192 OTUs correspond to named and candidate species. Twenty-eight other named species share OTUs, such as Azemiops feae and A. kharini, Gloydius halys, G. shedaoensis, and G. intermedius, and Bungarus multicinctus and B. candidus, representing inconsistencies most probably caused by imperfect taxonomy, recent and rapid speciation, weak taxonomic signal, introgressive hybridization, and/or inadequate phylogenetic signal. In contrast, 43 species and candidate species assign to two or more OTUs due to having large intraspecific distances. If most OTUs detected in this study reflect valid species, including the 36 candidate species, then 30% more species would exist than are currently recognized. Several OTU divergences associate with known biogeographic barriers, such as the Taiwan Strait. In addition to facilitating future studies, this reliable and relatively comprehensive reference database will play an important role in the future monitoring, conservation, and management of Chinese snakes.

[Association between sleep and prevalence of hypertension in elderly population]

Objective: To explore the association between sleep duration, sleep quality and the prevalence of hypertension in the elderly aged 65 years and above. Methods: This study was conducted among the elderly in communities in Yiwu, China from April to July, 2019, and participants were recruited through physical examination in the hospital. Face-to-face interview was performed to obtain basic information. Sleep duration and sleep quality were evaluated by Pittsburgh Sleep Quality Index (PSQI). Associations between sleep duration, sleep quality and hypertension were evaluated by multivariate logistic regression analysis. Results: A total of 3 169 elderly persons, aged ≥65 years old, were included in the study. The overall prevalence of hypertension was 50.8%. The elderly with very poor sleep quality and short sleep duration accounted for 22.4% and 28.5%, respectively. After adjusting for demographic characteristics, socioeconomic status, lifestyle and health status, the OR of hypertension for the elderly with very poor sleep quality was 1.42 (95%CI: 1.12-1.80) compared with those with very good sleep quality. Compared with the elderly with sleep duration of 6-7 h a night, the OR of hypertension for those with sleep duration <6 h was 1.37 (95%CI: 1.15-1.65). As the sleep quality decreased, the risk for hypertension increased. An U-shaped association was found between sleep duration and risk of hypertension. Subgroup analyses showed that this association existed in both men and women, but only significant in the elderly aged <75 years. Conclusion: Poor sleep quality and short sleep duration were associated with risk for hypertension in the elderly.

Contribution to the taxonomy of the genus Lycodon H. Boie in Fitzinger, 1827 (Reptilia: Squamata: Colubridae) in China, with description of two new species and resurrection and elevation of Dinodon septentrionale chapaense Angel, Bourret, 1933

While considerable progress has been made in the taxonomic studies of the genus Lycodon in Asia, questions remain to be clarified regarding the taxonomy of certain groups, particularly those containing species in China. Not only do many regions in China remain overlooked by herpetologists, resulting in the possibility of undiscovered new species, but the surveyed areas also have suspicious records of recognized congeners that require taxonomic confirmations. Combining both morphological and genetic data, we tackle these outstanding issues in the taxonomy of Lycodon in China. In particular, we discover two new species of Lycodon: one from the previously neglected hot-dry valley in the northern Hengduan Mountain Region close to Tibet, and another recluse and cryptic species from the L. fasciatus complex in the downtown park of a major city in southern Sichuan Province. Additionally, we clarify the distribution of L. septentrionalis in China and resurrect and elevate its junior synonym subspecies, Dinodon septentrionale chapaense, as a full, valid species, and we synonymize the recently described L. namdongensis to the resurrected L. chapaensiscomb. nov.. Lycodon chapaensiscomb. nov. thus represents a new national record of reptilian fauna of China. Lastly, based on literature review, we also correct some of the erroneous records of L. fasciatus and L. ruhstrati in China, point out remaining taxonomic issues of the genus for future research, and update the dichotomous key and distribution of the 20 species of Lycodon currently recorded from China.

[Evaluation of human milk feeding in hospitalized very low and extremely low birth weight infants]

Objective: To investigate the current situation of human milk (HM) feeding in hospitalized very low and extremely low birth weight infants. Methods: The study retrospectively extracted the data of 601 infants with birth weight <1 500 g, and admitted within 24 hours after birth to the Neonatal Intensive Care Unit of Nanjing Maternity and Child Health Care Hospital from January 2016 to December 2018. The infants were grouped into exclusive mother's-own-milk (MOM) group, donor human milk (DHM) group (partial or none MOM), and mixed (HM and formula) feeding group according to the feeding strategy. Qualitative and quantitative variables in the three groups were compared with One-way ANOVA, Kruskal-Wallis test, Chi-square test or Fisher exact test. Kappa and McNemar test were used for consistency testing. Results: Among the 601 infants (309 boys and 292 girls), 6 (1.0%) infants had never been fed with MOM. The gestational age and birth weight were (29.3±1.9) weeks and 1 260(1 115, 1 400) g in 601 infants. A total of 8 (1.3%) infants were grouped into MOM group, 542 (90.2%) were grouped into DHM group, and 51 (8.5%) were grouped into mixed feeding group. The percentage of enteral feedings with MOM in the stage of hospitalization 1-7 d, 8-14 d and 15-28 d were 73.6% (42.9%, 86.7%), 97.5% (78.6%, 100.0%) and 99.3% (93.0%, 100.0%), respectively (H=414.95, P<0.01), and the pairwise comparison suggested that the stage of hospitalization 1-7 d was the lowest (adjusted both P<0.05). The average weight adjusted daily dose of MOM were 9.7 (4.3, 18.2), 59.1 (26.5, 93.5) and 116.0 (60.3, 142.6) ml/(kg·d) in the stage of hospitalization 1-7 d, 8-14 d and 15-28 d, respectively (H=759.75, P<0.01), and the pairwise comparison suggested that the stage of hospitalization 1-7 d was the lowest (adjusted both P<0.05). The weight adjusted daily dose of MOM in exclusive MOM group, DHM and Mixed feeding group were 95.2 (40.0, 117.2), 82.9(53.6, 103.1) and 55.7 (16.6, 97.5) ml/(kg·d), respectively (H=10.78, P=0.005).Additionally, the percentage and weight adjusted daily dose of MOM showed a general consistency of 0.703 (P>0.05, Kappa=0.408). Conclusions: The rate of exclusive MOM feeding is low, especially during the first 7 days of hospitalization. The percentage of total enteral feedings with MOM and the average weight adjusted daily dose of MOM can well evaluate the situation of HM feeding during hospitalization quantitively.

[Disparity of minnesota multiphasic personality inventory between positions and its relationship with job burnout in a general hospital]

Objective: To explore the difference of personality characteristics of physicians, nurses, medical skills and administrative personnel in a general hospital and its influence on job burnout. Methods: Employee entered the hospital before 2018 were enrolled in the current study and the position was classified as physicians, nurses, medical technician and administrative staff. Minnesota Multiphasic Personality Inventory (MMPI) was completed by the employee at the time of entering the hospital. Status of job burnout was assessed in 2018 using the Maslach Burnout Inventory-General Survey (MBI-GS) . Results: Physicians have a higher rate of paranoia than others (P<0.05) , and administrative staff and medical technician have a slightly higher score than the other two categories of people (P<0.05) , and administrators lie at a higher rate than others (P<0.05) . Further analysis found that personality traits did not have a significant association with job burnout at the time of entry. Conclusion: The administrative and medical staff is slightly more irritable, the administrative staff lying slightly higher score, the staff after the entry of job burnout is not affected by the personality characteristics of the onboarding.

Quality assessment of groundwater from the south-eastern Arabian Peninsula

Assessment of groundwater quality plays a significant role in the utilization of the scarce water resources globally and especially in arid regions. The increasing abstraction together with man-made contamination and seawater intrusion have strongly affected groundwater quality in the Arabia Peninsula, exemplified by the investigation given here from the United Arab Emirates, where the groundwater is seldom reviewed and assessed. In the aim of assessing current groundwater quality, we here present a comparison of chemical data linked to aquifers types. The results reveal that most of the investigated groundwater is not suitable for drinking, household, and agricultural purposes following the WHO permissible limits. Aquifer composition and climate have vital control on the water quality, with the carbonate aquifers contain the least potable water compared to the ophiolites and Quaternary clastics. Seawater intrusion along coastal regions has deteriorated the water quality and the phenomenon may become more intensive with future warming climate and rising sea level.

Natural radioactivity in groundwater from the south-eastern Arabian Peninsula and environmental implications

Groundwater is the most valuable resource in arid regions, and recognizing radiological criteria among other water quality parameters is essential for sustainable use. In the investigation presented here, gross-α and gross-β were measured in groundwater samples collected in the south-eastern Arabian Peninsula, 67 wells in Unite Arab Emirates (UAE), as well as two wells and one spring in Oman. The results show a wide gross-α and gross-β activities range in the groundwater samples that vary at 0.01∼19.5 Bq/l and 0.13∼6.6 Bq/l, respectively. The data show gross-β and gross-α values below the WHO permissible limits for drinking water in the majority of the investigated samples except those in region 4 (Jabel Hafit and surroundings). No correlation between groundwater pH and the gross-α and gross-β, while high temperatures probably enhance leaching of radionuclides from the aquifer body and thereby increase the radioactivity in the groundwater. This conclusion is also supported by the positive correlation between radioactivity and amount of total dissolved solid. Particular water purification technology and environmental impact assessments are essential for sustainable and secure use of the groundwater in regions that show radioactivity values far above the WHO permissible limit for drinking water.

Model simulation of inflow water to the Baltic Sea based on ¹²⁹I

The semi-enclosed Baltic Sea represents a vital economic and recreational resource for more than 90 million people inhabiting its coasts. Extensive contamination of this sea by a variety of anthropogenic pollutants has raised the concern of the people in the region. Quantifying seawater inflow is crucial for estimating potential environmental risks as well as to find the best remedial strategy. We present here a model to estimate water inflow from the North Sea to the Baltic Sea by utilizing ¹²⁹I as a tracer. The results predicted inflow range of 230-450 km³/y with best fit value around 330 km³/y from the North Sea to the Baltic Sea during 1980-1999. Despite limited time series data on ¹²⁹I, the model presented here demonstrates a new management tool for the Baltic Sea to calculate inflow water compared to conventional methods (such as salinity, temperature and hydrographic models).

Birth weight and subsequent risk of obesity: a systematic review and meta-analysis

This report describes the association between birth weight (BW) and obesity. Screening of 478 citations from five electronic databases resulted in the inclusion of 33 studies, most of medium quality. The meta-analysis included 20 of these published studies. The 13 remaining articles did not provide sufficient dichotomous data and were systematically reviewed, revealing results consistent with the meta-analysis. Our results revealed that high BW (>4000 g) was associated with increased risk of obesity (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.91-2.24) compared with subjects with BW ≤ 4000 g. Low BW (<2500 g) was associated with decreased risk of obesity (OR, 0.61; 95% CI, 0.46-0.80) compared with subjects with BW ≥ 2500 g. However, when two studies exhibited selection bias were removed, the results indicated no significant association between low BW and obesity (OR, 0.77; 95% CI, 0.58-1.04). Sensitivity analyses showed that differences in the study design, sample size and quality grade of the study had an effect on the low BW/obesity association, which low BW was not associated with the risk of obesity in cohort studies, studies with large sample sizes and studies with high quality grades. Pooled results were similar when normal birth weight (2500-4000 g) was used as the reference category. Subgroup analyses based on different growth and developmental stages (pre-school children, school children and adolescents) also revealed that high BW was associated with increased risk of obesity from childhood to early adulthood. No significant evidence of publication bias was present. These results suggest that high BW is associated with increased risk of obesity and may serve as a mediator between prenatal influences and later disease risk.

Intelligence in relation to obesity: a systematic review and meta-analysis

We performed a systematic review describing obesity/intelligent quotient (IQ) association, particularly childhood IQ in relation to adulthood obesity. After screening 883 citations from five electronic databases, we included 26 studies, most of medium quality. The weighted mean difference (WMD) of the full IQ (FIQ)/obesity association in the pre-school children was -15.1 (P > 0.05). Compared with controls, the WMD of FIQ and performance IQ of obese children were -2.8 and -10.0, respectively (P < 0.05), and the WMD of verbal IQ was -7.01 (P > 0.05). With increasing obesity, the FIQ in pre-school children declined, with a significant difference for severely obese children and FIQ. In pubertal children, a slightly different effect of FIQ and obesity emerged. Two studies reported an inverse FIQ/obesity association in adults, but it was non-significant after adjusting for educational attainment. Four papers found that childhood FIQ was inversely associated with adult body mass index, but after adjusting for education, became null. Overall there was an inverse FIQ/obesity association, except in pre-school children. However, after adjusting for educational attainment, FIQ/obesity association was not significantly different. A lower FIQ in childhood was associated with obesity in later adulthood perhaps with educational level mediating the persistence of obesity in later life.

[Immunohistochemical studies of estrogen receptor in the heart of Gekko swinhonis]

AIM

To observed the expression of estrogen receptor (ER alpha and ER beta) in the heart of Gekko swinhonis.

METHODS

The immunohistochemical technique for the estrogen receptor was used.

RESULTS

The positive ER alpha and beta cells existed in cardiac myocytes and fibroblasts of the atria and the ventricles of Gekko swinhonis and had no sexual difference. The difference of ER alpha between the atria (11.56 +/- 1.67) and ventricles (6.68 +/- 1.88) was observed in both sexes (P < 0.01).

CONCLUSION

The atria are probably the main target tissue of estrogen through ER alpha pathway while some functions of whole heart will be regulated by estrogen through ER beta pathway. The sexual differences aren' t related to the content of ER. It may be involved in the state of activity and function of ER under the physiological conditions.

[Daily 1 h standing can prevent depression of myocardial contractility in simulated weightless rats]

Objective. To observe and compare the effect of daily standing of rats for different durations in alleviating the depression of myocardial contractility induced by simulated weightlessness. Method. Fifty male Sprague-Dawley rats were randomly assigned to five groups: simultaneous control (CON), four-week tail-suspension (SUS), SUS plus daily 1 h standing (STD1), SUS plus daily 2 h standing (STD2) and SUS plus daily 4 h standing (STD4). Four weeks later, wet weights of the left soleus, testis and adrenal gland were measured, and the isometric contractile tension and its time parameters of isolated perfused papillary muscles from rats of various groups were examined. Result. Compared with CON, the wet weights of testis in different treatment groups decreased significantly (P<0.05). The wet weight of soleus in SUS decreased by 58.9% (P<0.01); but in STD1, STD2 and STD4, decreased by 38.5%, 24.0% and 11.0% (P<0.01, or P<0.05) respectively. The relative protections were 34.7%, 59.2% and 81.4% (P<0.01) respectively. In SUS group, developed tension (DT), peak rate of tension rise (+dT/dtmax) and peak rate of tension fall (-dT/dtmax) decreased by 32.2%, 29.2% and 30.7% (P<0.05), and time to peak rate of tension rise (TPP) and time to peak tension (TPT) prolonged by 21.2% and 11.0% (P<0.05), respectively. Whereas in STD1, STD2 and STD4, all the parameters reflecting myocardial contractility (like DT, + dT/dtmax, -dT/dtmax and TPP), did not show any significant change as compared with those of CON. However, being an exception, TPT still showed obvious prolongation (P<0.05) in STD1. Conclusion. Daily 1 h standing could prevent depression of myocardial contractility in rat induced by medium-term simulated weightlessness. However, with respect to prevention of atrophic changes in soleus muscle and testis, daily standing for 1 h, 2 h, or 4 h was only partially effective and even totally devoid of any effect, respectively.

[Transition of soleus troponin I isoforms and atrophy of testis in tail-suspended rats]

Objective. To observe the transition time of soleus I (TnI) isoforms and to elucidate the relationship between soleus TnI transition and atrophy; and to analyze the time course between testis atrophy and soleus atrophy. Method. Eight groups of male rats were suspended for 3, 4, 5, 7, 14, 21, 28 and 42 d, respectively. Besides, three groups of female rats were suspended for 3, 4 and 5 d respectively. Wet and relative weights (wet weight/body weight) of testis and soleus were measured. The expression of TnI was observed by Western blot. Result. The relative weight of soleus of tail-suspended male rats decreased significantly after 4 d of suspension as compared with control. The degree of rats soleus atrophy in the first 14 d of suspension was greater than that after 14 d. The relative weight of testis showed the same change as that of soleus. There was no significant change in the relative weight of soleus in 4 d of tail-suspended female rats. The significant decrease in the relative weight of tail-suspended female rats began on the 5th day. The Western blot showed that the transition from slow skeletal TnI (ssTnI) to fast skeletal TnI (fsTnI) in the soleus occurred in 14 d of tail-suspension. Conclusion. The overt atrophy of tail-suspended male rats occurs on the 4th day. The soleus TnI transition from ssTnI to fsTnI is on the 14th day. It is suggested that the TnI is not the sensitive protein to gravity. The overt atrophy of female tail-suspended rats occurs at the 5th day. This indicated that the decrease in testosterone level may accelerate the atrophy of the soleus.

Peripheral effector mechanism hypothesis of postflight cardiovascular dysfunction

Studies on the mechanisms of cardiovascular dysfunction after space-flight are important to illustrate the cardiovascular effect of microgravity and develop appropriate multi-system countermeasures for future long-duration spaceflights. Over the past 10 yr, we have systematically studied the adaptational changes in structure and function of both the heart and vessels, using the tail-suspension rat model to simulate microgravity effects. Our results indicate that simulated microgravity induced atrophic changes and reduced contractility of the heart muscle, and upward- and downward-regulation in structure, function, and innervation state of vessels in the brain and hind body of the rat. In addition, more recent advances in relevant ground-based and space-flight studies from different laboratories have also been reviewed. Based on these studies, it has been speculated that, in addition to hypovolemia, the microgravity-induced adaptational changes in the structure and function of the two main effectors of the cardiovascular system, i.e., the arterial smooth muscle and the cardiac muscle, might be among the most important mechanisms responsible for postflight cardiovascular dysfunction and orthostatic intolerance. In this paper we will review the available evidence with comments.

A proteolytic NH2-terminal truncation of cardiac troponin I that is up-regulated in simulated microgravity

In a tail suspension rat model, we investigated changes in myofilament protein during cardiac adaptation in simulated microgravity. Contractile force and velocity of cardiac muscle were decreased in the tail suspension rats as compared with the control. Ca(2+)-dependent actomyosin ATPase activity was also decreased; however, sensitivity of cardiac muscle to Ca(2+) activation was unchanged. There was no change in expression of myosin heavy chain, tropomyosin, troponin T, or troponin I isoforms in hearts of tail suspension rats. A novel finding is a fragment of cardiac troponin I (cTnI) that had increased amounts in the heart of tail suspension rats. Binding of this cTnI fragment by a monoclonal antibody that specifically recognizes the COOH terminus indicates an intact COOH terminus. NH(2)-terminal sequence analysis of the cTnI fragment revealed truncations primarily of amino acids 1-26 and 1-27 and smaller amounts of 1-30, including Ser(23) and Ser(24), which are substrates of protein kinase A phosphorylation. This cTnI fragment is present in normal cardiac muscle and incorporated into myofibrils, indicating a role in regulating contractility. This proteolytic modification of cTnI up-regulated during simulated microgravity suggests a potential role of the NH(2)-terminal segment of cTnI in functional adaptations of cardiac muscle.

[Heat stress-induced HSP70 expression in heart and vessels of simulated weightless rats]

To examine the effect of simulated weightlessness on inducible HSP70 expression in the heart and vessel tissues of rats, a tail-suspension rat model was used to simulate weightlessness. HSP72 mRNA and HSP70 expression in heart and vessel tissues of both simulated weightless and control rats exposed to heat stress (ambient temperature, Ta = 43 degrees C) and recovered at Ta of 25 degrees C for 1 h (CON-H1, SUS-H1) or 2 h (CON-H2, SUS-H2) were analyzed using Northern blot and Western blot. The expression of HSP72 mRNA in the myocardium significantly decreased in SUS-H2, as compared with that of CON-H2 rats. The amount of HSP72 in the myocardium tended to decrease in both SUS-H1 and SUS-H2 groups, as compared with the corresponding control groups, but the differences were not statistically significant. The levels of inducible HSP70 expression in the vessels were related with their anatomical locations, for that the expression of both HSP72 mRNA and HSP72 significantly increased in basilar arteries, whereas it showed a slight decline in femoral arteries. The blunted HSP70 expression in myocardium suggests that simulated weightlessness may induce myocardial changes similar to those in aging. However, the HSP70 expression changes in arteries are in accord with the trend of differential adaptation changes in vessels to simulated weightlessness.

The highly conserved COOH terminus of troponin I forms a Ca2+-modulated allosteric domain in the troponin complex

The primary structure of the COOH-terminal region of troponin I (TnI) is highly conserved among the cardiac, slow, and fast skeletal muscle TnI isoforms and across species. Although no binding site for the other thin filament proteins is found at the COOH terminus of TnI, truncations of the last 19-23 amino acid residues reduce the activity of TnI in the inhibition of actomyosin ATPase and result in cardiac muscle malfunction. We have developed a specific monoclonal antibody (mAb), TnI-1, against the conserved COOH terminus of TnI. Using this mAb, isolation of the troponin complex by immunoaffinity chromatography from muscle homogenate and immunofluorescence microscopic staining of myofibrils indicate that the COOH terminus of TnI forms an exposed structure in the muscle thin filament. Binding of this mAb to the COOH terminus of cardiac TnI induced extensive conformational changes in the protein, suggesting an allosteric role of this region in the functional integrity of troponin. In the absence of Ca2+, the binding of troponin C and troponin T to TnI had very little effect on the conformation of the COOH terminus of TnI as indicated by the unaffected mAb affinity for the TnI-1 epitope. However, Ca2+ significantly increased the accessibility of the TnI-1 epitope on TnI in the presence of troponin C and troponin T. The results provide evidence that the COOH terminus is an essential structure in TnI and participates in the allosteric switch during Ca2+ activation of contraction.

[Peripheral effector mechanism hypothesis on cardiovascular dysfunction after spaceflight]

In the years of 1990's, we systematically studied the adaptational changes in structure and function of both the heart and the vessels during simulated weightlessness. In our serial work, the tail-suspension rat model was used to simulate the microgravity-induced cephalad shift and redistribution of blood. On the basis of the facts we observed and the more recent advances in space and ground-based studies in 1990's, we put forward a hypothesis to offer a possible explanation for the frequent occurrence of postflight cardiovascular dysfunction. It states that, in addition to the factor of hypovolemia, the microgravity-induced adaptational changes in the structure and function of the two main effectors of the cardiovascular system, i.e., the arterial smooth muscle and the cardiac muscle might be one of the most important mechanisms accounting for postflight cardiovascular dysfunction.

Changes in myocardial contractility and contractile proteins after four weeks of simulated [correction of simulate] weightlessness in rats

The interaction between the gravitational field, the position of the body, and the functional characteristics of the blood vessels determines the distribution of intravascular volume. In turn, this distribution determines cardiac pump function. One of the most profound circulatory changes that occurs in man during exposure to weightlessness is a cephalad redistribution of fluid caused by the lack of hydrostatic pressure in this microgravitative environment. The cephalad redistribution of fluid results in a loss of blood volume and then induces a decrease in preload. Recently, a decrease in sensitivity of arteriole to catecholamine has reported in rats of simulated weightlessness. This change in arteriole may reduce afterload. As a result, cardiovascular system may be shifted to a hypokinetic state during weightlessness condition for long-term. Echocardiographic data from astronauts during space flight showed an increase in heart rate, a 12 % decrease in stroke volume, and a 16 % decrease in left end diastolic volume. Electron-microscopic studies have shown changes in cardiac morphology in rats after exposure to microgravity for 7-12.5 days. After the COSMOS 2044 flight for 14 days, the light-microscopic studies have shown an atrophy of papillary muscles in rats left cardiac ventricle. It is not clear whether the function of atrophic myocardium is impaired. The data in three aspects as mentioned above suggest that weightlessness or simulated weightlessness may decrease the myocardial function. However, definite changes in cardiac performance have been hard to prove due to many limits. This studies were to answer two questions: Is the myocardial contractility depressed in rats subjected to simulated weightlessness for four weeks? What are the underlying mechanisms of the changing contractility?

Heat shock protein 70 expression in myocardium is blunted with simulated weightlessness

Exposure of cardiac cells to a mild thermal or ischaemic stress, sufficient to induce HSP expression, protects them against a subsequent exposure to a more severe ischaemic stress. Over expression of HSPs by transfection of herpes simplex virus vectors in vitro or in transgenic animal in vivo can protect primary cardiac cells from subsequent exposure to severe thermal or hypoxic stress. The increases in myocardial and liver HSP70 accumulation in response to nonexertional heat stress are attenuated with senescence, and hearts from aged animals exhibit an impaired ability to produce the protective HSP. In our previous work, peculiar changes associated with aging, like lipofuscin accumulation and collagen deposition were shown in the myocardial tissue of long-term simulated weightless rats. We therefore designed the present study to examine whether the heat-stress induced HSP70 accumulation in myocardial tissue may decline with simulated weightlessness.

[Echocardiographic assessment of left ventricular structure and function after simulated weightlessness in rats]

Objective. To investigate whether the changes in rat after simulated weightlessness are similar to those in astronaut after flight. Methods. The effects of 4 wk tail-suspension on left ventricular structure and function in rats were examined by echocardiography. Results. After 4 wk of simulated weightlessness, the thickness of both the anterior and posterior wall in left ventricle (LV) showed a general trend of decrease, but these changes were not statistically significant; the end-systolic and end-diastolic internal dimensions (ESD and EDD respectively) of LV decreased significantly; and the end-systolic volume, end-diastolic volume and stroke volume (ESV, EDV and SV respectively) were all reduced; so did the relevant indices of them. There were no significant differences in ejection fraction (EF) and fractional shortening (FS) between the tail-suspended and control groups. The left ventricular mass (LVM) and its index (LVMI) were decreased. The peak velocities of blood flow of aorta, pulmonary artery and mitral valve didn't show any significant change after simulated weightlessness. Conclusion. Medium-term simulated weightlessness may lead to a significant decrease in left ventricular internal dimension, ventricular volume, and mass, and a trend of decrease in mean left ventricular wall thickness. These changes in rats are similar to those observed in astronauts postflight.

Plasticity of arterial vasculature during simulated weightlessness and its possible role in the genesis of postflight orthostatic intolerance

Even after several decades of extensive research, the basic mechanism of postflight cardiovascular dysfunction has not yet been fully elucidated. It is now well recognized that multiple mechanisms might account for the frequent occurrence of significant postflight orthostatic intolerance. It has been found that all tissues adapt their design when exposed to sustained alteration in local activity and/or stress. The most obvious example is the musculo-skeletal system, structure and function of which might be severely affected during microgravity exposure. In an attempt to elucidate whether structure and function of cardiac and vascular smooth muscle might be affected by simulated by microgravity, a serial work was started several years ago. In this paper, we present our more recent findings on plasticity of arterial vasculature and its innervation state during and after simulated microgravity and its time course.

Time course and reversibility of arterial vasoreactivity changes in simulated microgravity rats

Recent works have shown that postflight orthostatic intolerance involves multiple alterations in physiological function during actual or simulated microgravity. In our previous work, we demonstrated that 14-day tail-suspension resulted in an impaired ability of vascular smooth muscle to develop tension in arteries confined to the hindquarter, which have been suggested as an important factor accounting for the occurrence of orthostatic intolerance. To our knowledge, data on arterial vasoreactivity alterations induced by simulated microgravity longer than two weeks are not found. The aim of the present work was to characterize the time course of alterations in vasoconstrictor properties of hindquarter arteries during tail-suspension up to eight weeks, and to examine whether these alterations are reversible.

Localization of the potassium ion activation site in human liver fructose 1,6-bisphosphatase

Three mouse monoclonal antibodies of human liver fructose 1,6-bisphosphatase are shown to bind to the enzyme at different sites as determined by ELISA. The binding of one of the monoclonal antibodies, L2E1, mimics the effects of K+ ions, including increase in the enzyme activity and enhancement of the sensitivity of the enzyme to AMP inhibition. We tentatively suggest that human liver FruP2ase may have a specific K+ activation site, which at least partially overlaps with the L2E1 binding region. This site has been localized by analyzing the peptide fragments formed by cleavage with cyanogen bromide.

[Uveitis and immune complexes]

The mean level of circulating immune complexes (CIC) in 24 uveitic patients determined by PEG deposition with the biochemical analyzor was found to be 28.458 +/- 7.796, in contrast to the value of 14.499 +/- 6.194 in the control group. The CIC level in acute iridocyclitis and panuveitis was significantly elevated compared with those in other types of uveitis. The results again demonstrated that most cases of uveitis, especially those of unknown origin, were related with immune complexes, and changes in the level of CIC could also be an indicator of therapeutic effects.