Effect of vitamin D3 supplementation in winter on physical performance of university students: a one-month randomized controlled trial

BACKGROUND

There is epidemiological evidence which suggests an association between 25-hydroxyvitamin D [25(OH)D] levels and bone and muscle function; however, it is unclear whether vitamin D supplementation has an added benefit beyond bone health. Here, we investigated the effects of vitamin D3 supplementation (1 month) on physical performance in Chinese university students in winter.

METHODS

One hundred and seventeen eligible subjects with 25(OH)D (19.2 ± 7.8 ng/mL) were randomly assigned to either vitamin D3 supplement (N = 56; 1000 IU/day) or the control (N = 61) group for 1 month. Pre- and post-measurements included: 1) serum levels of 25(OH)D; 2) musculoskeletal and pulmonary function [vertical jump height (VJH) and right handgrip strength (RHS), forced vital capacity (FVC), and forced expiratory volume at 1s (FEV1)]; 3) bone turnover markers [parathyroid hormone (PTH), n-terminal osteocalcin (N-MID), and calcium]; 4) hemoglobin-related parameters [hemoglobin (Hb), hematocrit (HCT), red blood cells (RBC), and red cell distribution width (RDW)]; 5) lipid parameters [total triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)]; 6) Fatigue-related indicators [serum creatine kinase (CK), lactate dehydrogenase (LDH), and total testosterone (T)]. In addition, aerobic capacity was assessed by measuring maximal oxygen uptake (VO2max) at baseline.

RESULTS

During wintertime, supplementation with 1000 IU/d of vitamin D3 significantly increased serum 25(OH)D levels (from 18.85 ± 7.04 to 26.98 ± 5.88 ng/mL, p < 0.05), accompanied by a decrease of PTH (p < 0.05). However, vitamin D3 supplementation did not significantly impact the physical performance, serum lipid parameters, and bone turnover markers of students. Furthermore, 25(OH)D was found to be positively correlated with VJH and negatively correlated with PTH and TC at the beginning and end of the study (p < 0.05). In addition, the multiple linear regression analysis showed that 25(OH)D combined with athletic, gender, height, weight, Hb, and FVC could account for 84.0% of the VO2max value.

CONCLUSIONS

The study demonstrated that one-month of 1000 IU/d of vitamin D3 supplementation during the winter had beneficial effects on 25(OH)D status and PTH. However, vitamin D3 intervention was not sufficient to improve physical performance. Furthermore, 25(OH)D levels combined with athletic, Hb and FVC could be a predictor of VO2max.

[Associations between different levels of blood pressure and risk of prediabetes]

Objective: To explore sex and rural-urban differences in the associations of different blood pressure levels with the risk of prediabetes. Methods: We used a multi-stage stratified cluster random sampling method to investigate 21 637 residents aged ≥18 years from 10 survey areas in Hubei province in 2020. The data on questionnaire, physical measurements, and laboratory indicators of the participants were collected. The associations of different blood pressure levels with risk of prediabetes by sex and regions were analyzed using multivariate logistic regressions after complex weighting. Results: A total of 16 111 subjects were included. The prevalence (95%CI) of prediabetes, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and IFG complicated with IGT were 25.1% (14.4%-35.9%), 12.7% (3.2%-22.1%), 8.1% (6.3%-9.8%), and 4.4% (2.3%-6.5%), respectively. After multivariate adjustment, the risk of prediabetes, IFG, IGT, and IFG complicated with IGT increased with the increment of blood pressure (both P for trend <0.05). The positive dose-response relationships between blood pressure levels and risk of prediabetes were also significant among male, urban, and rural residents (both P for trend <0.05), and the interactions between sex and blood pressure showed significant associations for risk of prediabetes and IGT (both P for interaction <0.05). Conclusions: Higher blood pressure levels were associated with an increased risk of prediabetes. The association with prediabetes was stronger in males, but no significant difference was found between urban and rural residents. More distinctive and effective prevention and control strategies should be developed for different populations.

[Analysis of the whole genome traceability and transmission path simulation experiment of the local cluster COVID-19 epidemic]

Objective: To trace and characterize the whole genome of SARS-CoV-2 of confirmed cases in the outbreak of COVID-19 on July 31, 2021 in Henan Province. Method: Genome-wide sequencing and comparative analysis were performed on positive nucleic acid samples of SARS-CoV-2 from 167 local cases related to the epidemic on July 31, 2021, to analyze the consistency and evolution of the whole genome sequence of virus. Results: Through high-throughput sequencing, a total of 106 cases of SARS-CoV-2 whole genome sequences were obtained. The results of genome analysis showed that the whole genome sequences of 106 cases belonged to the VOC/Delta variant strain (B.1.617.2 clade), and the whole genome sequences of 106 cases were shared with the genomes of 3 imported cases from Myanmar admitted to a hospital in Zhengzhou. On the basis of 45 nucleotide sites, 1-5 nucleotide variation sites were added, and the genome sequence was highly homologous. Conclusion: Combined with the comprehensive analysis of viral genomics, transmission path simulation experiments and epidemiology, it is determined that the local new epidemic in Henan Province is caused by imported cases in the nosocomial area, and the spillover has caused localized infection in the community. At the same time, it spills over to some provincial cities and results in localized clustered epidemics.

[Study of portal venous pressure gradient to predict high-hepatic encephalopathy-risk population post TIPS]

Transjugular intrahepatic portosystemic shunt (TIPS) can effectively reduce the portal venous pressure and relieve the clinical complications related to portal hypertension. However, hepatic encephalopathy (HE) is still the main complication post TIPS. Studies have shown that patients over 65 years old with liver function reserve in Child-Pugh grade C are the high-HE-risk group post TIPS, and early TIPS treatment can benefit the survival of these high-risk patients. In this study, TIPS was used to treat 60 cases aged > 65 years old and liver function reserve in Child-Pugh grade C (decompensated liver cirrhosis) with esophagogastric variceal bleeding. The clinical results of 1-year was observed and the porto systemic gradient (PSG) was evaluated. The relationship between the incidence of HE and the PSG of patients with and without HE were compared to evaluate the effect of PSG on the incidence of HE.

Gout in China, 1990-2017: the Global Burden of Disease Study 2017

OBJECTIVE

The aim of the study was to estimate the gout burden and risk factors in China from 1990 to 2017.

STUDY DESIGN

The Global Burden of Disease (GBD) Study uses various analytical tools and a diverse set of data sources to generate comparable estimates of deaths and mortality rates broken down by age, sex, cause, year, and geography.

METHODS

We used the results from the GBD Study 2017 to compare disability-adjusted life years (DALYs), prevalence, incidence, and risk factors of gout in China. The median of the percentage change and 95% uncertainty intervals were determined for the period between 1990 and 2017.

RESULTS

The age-standardized DALY rate, prevalence, and incidence increased 6.92%, 6.88%, and 6.16%, respectively, in China from 1990 to 2017. Although the rates of gout both globally and in China were increasing, the range of change for males in China was larger than that of the global level. All risk factors combined accounted for 30.04% of gout DALYs in 2017. The leading risk factors for gout DALYs were high body mass index and impaired kidney function, and the proportion of high body mass index increased significantly from 10.67% to 24.31%, whereas the proportion of impaired kidney function remained basically unchanged.

CONCLUSIONS

The age-standardized DALY rate, prevalence, and incidence in China have increased progressively since 1990. Increasing attention on body weight management should be prioritized for controlling the rising prevalence of gout in the young and middle-aged population.

[Review on the etiology and complications of hand, foot and mouth disease, using data from the national sentinel surveillance program, in China, 2015-2016]

Objective: To understand the characteristics relating to the etiology and complications of hand, foot and mouth disease (HFMD) based on data from the pilot National Sentinel Surveillance (NSS) program so as to explore the feasibility, advantages and disadvantages of the NSS. Methods: Data were extracted from the NSS system, conducted in 11 provinces of China from November 2015 to October 2016. Characteristics regarding the etiology, complications of HFMD and factors related to the positive rates of HFMD specimens were analyzed under the logistic regression method by SPSS 20.0 software. Results: A total of 4 783 specimens were collected, including 3 390 from mild, 1 390 from severe and 3 from death cases. The overall positive rate was 81.43% (3 895/4 783). Other enteroviruses (non EV71/Cox A16 enteroviruses) appeared the major serotype (52.68%, 1 482/2 813) for mild infection of the disease while EV71 was for the severe cases (65.31%, 706/1 081). The serotype spectrum revealed by the pilot NSS was almost identical with the existing surveillance system. Other enteroviruses tended to infect younger children (χ(2)=130.17, P<0.001) than EV71 and Cox A16, in China. The multivariate logistic regression results showed that higher positive rate was associated with specimens which were collected from males, at children' hospitals, in peak seasons, timely and in stools. The positive rates presented downwarding trends with the extension of the onset-sampling interval (χ(2)=14.47, P<0.001 in stool specimen; χ(2)=31.99, P<0.001 in throat swab; χ(2)=24.26, P<0.001 in anal swab). Aseptic meningitis, non-brainstem encephalitis and brainstem encephalitis appeared the top three complications of both EV71-associated and other enteroviruses-associated severe HFMD cases. Conclusions: Factors as gender, season/place/timeliness of specimen collection, and types of hospital all appeared independently influenced the positive rates. NSS seemed feasible to be used as an alternative or supplement tool to the existing surveillance program in China.

Prevalence and Characteristics of Liver Fibrosis Detected by Elastography: Results from the Cameron County Hispanic Cohort

Mexican Americans in south Texas have among highest rates of hepatocellular carcinoma (HCC) in the US. Non-invasive measures of liver fibrosis are needed to identify those at high risk of HCC. The purpose of the study was to determine the prevalence of and factors associated with liver fibrosis using acoustic radiation force impulse (ARFI) elastography, an accurate and non-invasive modality, in the Cameron County Hispanic Cohort (CCHC). Methods. The CCHC is a well characterized population-based cohort in south Texas. Liver stiffness was measured by ARFI in 404 participants in the CCHC by two separate operators. Median liver stiffness &gt; 1.34 m/s was considered significant (F2-F4) fibrosis. Ultrasound was used to determine presence of steatosis. Absence of HCV and HBsAg antigen, and absence of heavy drinking, was considered non-alcoholic fatty liver disease (NAFLD). We calculated design-based prevalence of fibrosis and determined clinical associations with (1) significant fibrosis and (2) simple steatosis using multinomial logistic regression. Results. Mean age was 51.1 years, 44.6% were male, and 29.1% had diabetes. The prevalence of significant fibrosis was 16.5%. In the fibrosis group, most (47/57, 84%) had NAFLD. We excluded participants with etiologies other than NAFLD for further analyses. After adjustment for age and sex, hypertension [Odds Ratio (OR) 3.0, 95% confidence interval (CI) 1.1–8.1), platelet count (OR 0.6, 95% CI, 0.5–1.0), and potassium level (OR 1.5, 95% CI, 1.1–2.0) were significantly associated with fibrosis, but not steatosis. HDL cholesterol (OR 0.5, 95% CI, 0.4–0.7), obesity (OR 2.2, 95% CI, 1.2–4.0) and insulin level (OR 2.1, 95% CI, 1.2–3.7) were significantly associated with steatosis, but not fibrosis. Elevated fasting glucose, diabetes, and elevated ALT levels were significantly associated with both steatosis and fibrosis. Conclusion. This is the first population-based application of liver elastography in the US. We find a high prevalence of fibrosis in Mexican Americans, dominated by NAFLD. Our results indicate a higher burden of fibrosis than population-based studies of liver fibrosis conducted elsewhere. We urge community intervention for the early detection of liver disease and prevention of NAFLD-related HCC.

Effects of PEMFs on Osx, Ocn, TRAP, and CTSK gene expression in postmenopausal osteoporosis model mice

Objective: Ovariectomized mice were used to simulate the symptoms of postmenopausal women with osteoporosis, and observe the effects of PEMF treatment on expression of Osx, Ocn, TRAP, and CTSK in ovariectomized mice. Methods: Thirty-week-old wild-type C57BL/6 mice were randomly divided into three groups (n=10, each group): sham operation group, ovariectomy (OVX) group, and PEMF group. Mice in the sham group underwent sham ovariectomy, while mice in the remaining two groups were ovariectomized. On postoperative day two, mice in the PEMF treatment group received PEMF treatment at a frequency of 8 Hz and an intensity of 3.8 mT for one hour daily for four weeks. At the same time, mice in the remaining two groups were placed in the PEMF treatment area under power-down state daily, similar to that in the PEMF group. After four weeks, all relevant indicators were tested. Results: (1) Compared with mice in the sham group, the number of trabecular bones significantly decreased, the thickness of the trabecular bone became thinner, the number of osteoclasts significantly increased, the gene expression of Osx and Ocn significantly decreased, and the gene expression of TRAP and CTSK significantly increased in the OVX group (P<0.01). (2) Compared with the blank controls without operation, the number of osteoblasts increased in the PEMF group. (3) Compared with the OVX group, the number of osteoclasts significantly decreased, the expression of Osx and Ocn significantly increased, and the gene expression of TRAP and CTSK significantly decreased in the PEMF group (P<0.01). Conclusion: PEMF treatment can significantly promote bone formation, which may be realized through inhibition of osteoclast formation, achieving bone morphological protection. PEMFs can significantly upregulate Osx and Ocn osteogenesis-related genes, which affect bone formation, and downregulate TRAP and CTSK osteoclast-related genes, which affect bone resorption. PEMFs may be used to treat postmenopausal osteoporosis by regulating Osx, Ocn, TRAP, and CTSK gene expression.

[Effect of umbilical cord mesenchymal stem cell transplantation on immune function and prognosis of patients with decompensated hepatitis B cirrhosis]

Objective: To investigate the effect of human umbilical cord mesenchymal stem cells (hUCMSCs) on the immune function and prognosis of patients with decompensated hepatitis B cirrhosis. Methods: A total of 65 patients with decompensated hepatitis B cirrhosis were divided into observation group and control group. The patients in the observation group were given intervention (via the proper hepatic artery or the portal vein) and intravenous infusion of 4×10⁸ hUCMSCs in two doses, as well as the same basic treatment as in the control group. The patients in the control group were given conventional medical treatment. ELISA as used to measure the serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNFα), interleukin-10 (IL-10), and transforming growth factor-β (TGFβ) in the observation group before surgery and at 1 week after surgery, as well as the serum levels of IL-6, TNFα, IL-10, and TGFβ in the control group on admission and at 1 week after admission. Flow cytometry was used to measure the percentage of lymphocyte subsets in the observation group before surgery and at 1 week after surgery, as well as that in the control group on admission and at 1 week after admission. In addition, the patients' prognosis and major complications during hospitalization were observed in both groups, and the patients were followed up for 24 weeks to record the number of deaths. The t-test was used for comparison of continuous data, and the chi-square test was used for comparison of categorical data which were expressed as percentages. Results: At 1 week after the transplantation of hUCMSCs, compared with the control group, the observation group had significant reductions in the serum levels of IL-6 and TNFα and significant increases in the serum levels of IL-10 and TGFβ (all P < 0.001), as well as significant increases in the percentages of T4 cells and Treg cells and significant reductions in the percentages of T8 cells and B cells (all P < 0.05). There were no significant differences in the changes in T3 cells and natural killer cells between the two groups (P > 0.05). Compared with the control group, the observation group had a significantly lower probability of progression to liver failure (6.45% vs 14.71%, P = 0.017). Conclusion: In the treatment of patients with decompensated hepatitis B cirrhosis, transplantation of UCMSCs can inhibit the proliferation of T cells and B cells and the differentiation of T8 cells, upregulate Treg cells, promote the secretion of immunosuppressive cytokines, and reduce the production of inflammatory cytokines. Therefore, it can alleviate liver inflammatory response and liver cell damage and reduce the probability of hepatic failure.

[Severe cases with hand, foot and mouth disease: data based on national pilot hand, foot and mouth disease surveillance system]

Objective: To investigate the clinical severity, etiological classification and risk factors of severe cases with hand, foot and mouth disease (HFMD). Methods: A total of 1 489 records on severe and fatal HFMD cases reported to the national pilot surveillance system of HFMD were used to analyze the demographic, medical treatment, etiological classification of the cases. Treatment outcome related risk factors were also studied with multi-variable stepwise logistic regression method. Results: Seven out of the 1 489 severe HFMD cases died of this disease. A total of 960 (72.9%) were under three years old and 62.9% were male and most of the cases (937, 62.9%) resided in rural areas. Among all the cases, 494 (33.2%) went to seek the first medical assistance at the institutions of village or township level. Durations between disease onset and first medical attendance, being diagnosed as the disease or diagnosed as severe cases were 0(0-1) d, 1 (0-2) d and 2 (1-4) d, respectively. In total, 773 (51.9%) of the severe HFMD cases were diagnosed as with aseptic meningitis, 260 (17.5%) with brainstem encephalitis, 377 (25.3%) with non-brainstem encephalitis, 6 (0.4%) with encephalomyelitis, 1 (0.1%) with acute flaccid paralysis, 4 (0.3%) with pulmonary hemorrhage/pulmonary edema and 68 (4.6%) with cardiopulmonary failure. Of the etiologically diagnosed 1 217 severe and fatal HFMD cases, 642 (52.8%) were with EV71, other enterovirus 261 (21.5%), Cox A16 36 (3.0%), 1 (0.1%) with both EV71 and Cox A16. However, 277 (22.8%) showed negative on any pathogenic virus. Complication (Z=3.15, P=0.002) and duration between onset and diagnosed as severe cases (Z=3.95, P<0.001) were shown as key factors related to treatment outcomes. Conclusions: Most severe HFMD cases appeared in boys, especially living in the rural areas. Frequently seen complications would include aseptic meningitis, non-brainstem encephalitis and brainstem encephalitis. EV71 was the dominant etiology for severe and fatal cases. Early diagnosis and complication control were crucial, related to the treatment outcome of HFMD.

[Human enterovirus infection status and clinical characteristics of 274 patients with viral encephalitis in Henan Province, 2011-2012]

Objective: To investigate human enterovirus (HEV) infection and clinical characteristics of viral encephalitis patients in Pingdingshan, Henan Province. Methods: Cerebrospinal fluid specimens and epidemiological information were collected from 274 viral encephalitis patients in the departments of pediatrics and neurology in hospitals in Pingdingshan, Henan Province, from April 2011 to August 2012. Patients with bacterial infections were excluded from the study. Demographic information was collected by questionnaires and clinical information was mainly obtained from hospital examinations. Viral RNA was extracted using magnetic bead extraction. Real-time RT-PCR was then performed for HEV, CV-A16, and EV-A71 testing. SPSS statistical software was statistical analyses. Significant differences were determined using the chi-squared test (P<0.05). Results: Among 274 cases of viral encephalitis, 180 cases (65.7%) were male and 94 cases were female (34.3%). The median age was 2.17 years. Approximately 61.3% (168) of patients were younger than 3 years of age. A total of 107 (39.1%), 2 (0.7%), and 42 (15.3%) cases were positive for HEV, CV-A16, and EV-A71, respectively. Eleven patients were younger than 6 months of age and one patient was co-infected with HEV and EV-A71. In the<3, 3-5, 6-15, and>15 years old age groups, HEV infections comprised 31.5% (53/168), 52.9% (18/34), 53.0% (35/66), and 16.7% (1/6) (χ(2)=13.10, P=0.003), respectively. The EV-A71 infection rates were 17.9% (30/168), 23.5% (8/34), 6.1% (4/66), and 0 (χ(2)=8.04, P=0.045), respectively. The other enterovirus (OEV) infection rates were 12.5% (21/168), 29.4% (10/34), 48.5% (32/66), and 16.7% (1/6) (χ(2)=35.19, P<0.001), respectively. The rate of vomiting in OEV and EV-A71 infected patients was 73% (44/60) and 26% (11/42), respectively, while the frequency of skin rash in OEV and EV-A71 infected patients was 32% (19/60) and 79% (33/42), respectively. Approximately 95% (99/104) of patients infected with HEV had a fever, and the breathing rhythm change rate was 19% (20/104), which was lower than that of patients without HEV infection (36.8% (60/163)) (χ(2)=9.35, P=0.002). Conclusion: In Pingdingshan, HEV was a major causative agent of viral encephalitis and the rate of OEV infection was high, especially in children aged 3-15 years old. Fever was a common clinical symptom of patients infected with HEV. Patients infected with OEV primarily exhibited vomiting symptoms and EV-A71 infected patients showed skin rash.

Phase II study of sorafenib in combination with cisplatin and 5-fluorouracil to treat recurrent or metastatic nasopharyngeal carcinoma

BACKGROUND

We aimed to investigate the efficacy and tolerability of sorafenib combined with cisplatin and 5-fluorouracil (5-FU) in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

It was a Simon two-stage designed trial. Chemotherapy-naive patients with recurrent or metastatic disease were enrolled. The regimen was sorafenib 400 mg orally b.i.d., cisplatin 80 mg/m(2) i.v. day 1, and 5-FU 1000 mg/m(2)/day CIV for 4 days, repeated every 21 days. After a maximum of six cycles of chemotherapy, patients received maintenance of sorafenib.

RESULTS

In total, 54 patients were enrolled. The objective response rate reached 77.8%, including 1 complete response and 41 partial responses. The median progression-free survival was 7.2 months (95% CI 6.8-8.4 months), and the median overall survival was 11.8 months (95% CI 10.6-18.7 months). Major toxic effects included hand-foot skin reaction, myelosuppression, and gastrointestinal (GI) reaction. The incidence of hemorrhage was 22.2%, and one patient with liver metastases died of GI bleeding. Contrast-enhanced ultrasonography was carried out in a subset of patients with liver metastases.

CONCLUSION

Combination of sorafenib, cisplatin (80 mg/m(2)) and 5-FU (3000 mg/m(2)) was tolerable and feasible in recurrent or metastatic NPC. Further randomized trials to compare sorafenib plus cisplatin and 5-FU with standard dose of cisplatin plus 5-FU in NPC are warranted.

Variation of respiratory resistance suggests optimization of airway caliber

Physiologically optimized processes, such as respiration, walking, and cardiac function, usually show a range of variability about the optimized value. Airway resistance has, in the past, been noted as variable, and this variability has been connected to pulmonary disease (e.g., asthma). A hypothesis was presented many years ago that postulated airway resistance as an optimized parameter in healthy individuals, and we have noticed that respiratory measurements made with the airflow perturbation device (APD) tend to be variable in nature. It was posited that this variability indicates that respiratory resistance is optimized similarly to other physiological processes. Fifty subjects with a wide range of demographics volunteered to have 100 measurements made of their respiratory resistances. Resistances were separated into inhalation and exhalation phases. These were plotted and shown to have frequency distributions that were consistent with expectations for an optimized process. The frequency distributions were not quite symmetrical, being skewed slightly toward upper resistances. Comparison between subject data and data from a mechanical respiratory analog showed that subject resistance variation is overwhelmingly from the respiratory system and not from the APD.

The management of hepatitis C

Hepatitis C is a serious public health problem with more than 170 million chronic carriers worldwide. Although hepatitis C infection can be cured in up to 40% of patients, current treatment is not ideal and is associated with a wide spectrum of side effects and complications. Therefore, emerging evidence suggests that patients can receive tailored therapy based on their viral kinetic changes during treatment. With better knowledge of hepatitis C viral genome and life cycle, compounds so called ''Specifically Targeted Antiviral Therapy for HCV or STAT-C'' are under development. This review will discuss current therapies and recent advances in new therapies for hepatitis C.

Determination of the absolute configurations of natural products using TDDFT optical rotation calculations: the iridoid oruwacin

We report the determination of the absolute configuration (AC) of the iridoid natural product oruwacin by comparison of the optical rotations, [alpha] D, of its two enantiomers, calculated using time-dependent density functional theory (TDDFT), to the experimental [alpha] D value, +193. Conformational analysis of oruwacin using density functional theory (DFT) identifies eight conformations which are significantly populated at room temperature. [alpha] D values of these eight conformations are calculated using TDDFT at the B3LYP/aug-cc-pVDZ//B3LYP/6-31G* level, leading to the conformationally averaged [alpha] D values of -193 for the (1 R,5 S,8 S,9 S,10 S)-enantiomer and +193 for the (1 S,5 R,8 R,9 R,10 R)-enantiomer. Comparison of the calculated [alpha] D values to the value of the natural product proves that naturally occurring oruwacin has the AC 1 S,5 R,8 R,9 R,10 R. This AC is opposite to that assigned by Adesogan by comparison of the [alpha] D of oruwacin to that of the iridoid plumericin. Our results show that the assignment of the AC of a natural product by comparison of its [alpha] D to that of a chemically related molecule can be unreliable and should not be assumed to be definitive.

Determination of the Absolute Configurations of Natural Products via Density Functional Theory Calculations of Vibrational Circular Dichroism, Electronic Circular Dichroism, and Optical Rotation: The Iridoids Plumericin and Isoplumericin

The absolute configurations (ACs) of the iridoid natural products, plumericin (1) and isoplumericin (2), have been re-investigated using vibrational circular dichroism (VCD) spectroscopy, electronic circular dichroism (ECD) spectroscopy, and optical rotatory dispersion (ORD). Comparison of DFT calculations of the VCD spectra of 1 and 2 to the experimental VCD spectra of the natural products, (+)-1 and (+)-2, leads unambiguously to the AC (1R,5S,8S,9S,10S)-(+) for both 1 and 2. In contrast, comparison of time-dependent DFT (TDDFT) calculations of the ECD spectra of 1 and 2 to the experimental spectra of (+)-1 and (+)-2 does not permit definitive assignment of their ACs. On the other hand, TDDFT calculations of the ORD of (1R,5S,8S,9S,10S)-1 and -2 over the range of 365-589 nm are in excellent agreement with the experimental data of (+)-1 and (+)-2, confirming the ACs derived from the VCD spectra. Thus, the ACs initially proposed by Albers-Schönberg and Schmid are shown to be correct, and the opposite ACs recently derived from the ECD spectra of 1 and 2 by Elsässer et al. are shown to be incorrect. As a result, the ACs of other iridoid natural products obtained by chemical correlation with 1 and 2 are not in need of revision.

Convergent coevolution in the domestication of coral mushrooms by fungus-growing ants

Comparisons of phylogenetic patterns between coevolving symbionts can reveal rich details about the evolutionary history of symbioses. The ancient symbiosis between fungus-growing ants, their fungal cultivars, antibiotic-producing bacteria and cultivar-infecting parasites is dominated by a pattern of parallel coevolution, where the symbionts of each functional group are members of monophyletic groups. However, there is one outstanding exception in the fungus-growing ant system, the unidentified cultivar grown only by ants in the Apterostigma pilosum group. We classify this cultivar in the coral-mushroom family Pterulaceae using phylogenetic reconstructions based on broad taxon sampling, including the first mushroom collected from the garden of an ant species in the A. pilosum group. The domestication of the pterulaceous cultivar is independent from the domestication of the gilled mushrooms cultivated by all other fungus-growing ants. Yet it has the same overall assemblage of coevolved ant-cultivar-parasite-bacterium interactions as the other ant-grown fungal cultivars. This indicates a pattern of convergent coevolution in the fungus-growing ant system, where symbionts with both similar and very different evolutionary histories converge to functionally identical interactions.

Strong phase-controlled fiber Bragg gratings for dispersion compensation

Dispersion-compensating fiber Bragg gratings with approximately 99.9% reflectivity that are made by continuous apodization and phase control are demonstrated. These strong dispersion-compensating gratings provide precision second-order, third-order, or even more complex dispersion compensation, as well as sufficient transmission isolation to be used at add-drop stages without additional filtering. A 99.84% grating with a constant approximately 700-ps/nm dispersion and a 99.94% grating with dispersion varying linearly from 1000 to -1000 ps/nm are demonstrated.

Studies of the inheritance of seed qualities and the exploitation of F2 heterosis in low gossypol strains in upland cotton

Twenty cross combinations were made with 4 recessive glandless lines (gl2gl2 gl3gl3) used as females and 5 dominant glandless lines (Gl2eGl2e Gl3Gl3) used as male parents to estimate the genetic variance components of kernel oil and protein content of seeds, oil and protein index, and kernel index using a genetic model for parents, F2 and F3. The results showed that all the analyzed traits were mainly controlled by additive effects. Oil content was controlled mainly by maternal additive effect, and other traits by direct additive effect. The average heterosis of F2 over mid-parent based on population mean was -1.99% to 1.11% for all these traits. It suggests that little inbreeding depression exists for F2 and F3 seeds. There were 75% and 60% of the F2 and the F3 combinations in which open-pollinated seeds contained gossypol levels lower than 0.4 gkg-1. This result indicated that it is possible to screen and select high yielding F2 hybrids with a gossypol content lower than the regulated criterion and without lowering seed quality.

Effect of site-directed mutagenesis of the conserved aspartate and glutamate on E. coli undecaprenyl pyrophosphate synthase catalysis

Undecaprenyl pyrophosphate synthase (UPPs) catalyzes condensation of eight molecules of isopentenyl pyrophosphate with farnesyl pyrophosphate to yield C(55)-undecaprenyl pyrophosphate. We have mutated the aspartates and glutamates in the five conserved regions (I to V) of UPPs protein sequence to evaluate their effects on substrate binding and catalysis. The mutant enzymes including D26A, E73A, D150A, D190A, E198A, E213A, D218A, and D223A were expressed and purified to great homogeneity. Kinetic analyses of these mutant enzymes indicated that the substitution of D26 in region I with alanine resulted in a 10(3)-fold decrease of k(cat) value compared to wild-type UPPs. Its IPP K(m) value has only minor change. The mutagenesis of D150A has caused a much lower IPP affinity with IPP K(m) value 50-fold larger than that of wild-type UPPs but did not affect the FPP K(m) and the k(cat). The E213A mutant UPPs has a 70-fold increased IPP K(m) value and has a 100-fold decreased k(cat) value compared to wild-type. These results suggest that D26 of region I is critical for catalysis and D150 in region IV plays a significant role of IPP binding. The E213 residue in region V is also important in IPP binding as well as catalysis. Other mutant UPPs enzymes in this study have shown no significant change (<5-fold) of k(cat) with exception of E73A and D218A. Both enzymes have 10-fold lower k(cat) value relative to wild-type UPPs.

Product distribution and pre-steady-state kinetic analysis of Escherichia coli undecaprenyl pyrophosphate synthase reaction

Undecaprenyl pyrophosphate synthase (UPPs) catalyzes the condensation of eight molecules of isopentenyl pyrophosphate (IPP) with farnesyl pyrophosphate (FPP) to generate C(55) undecaprenyl pyrophosphate. We investigated the kinetics and mechanism of this reaction pathway using Escherichia coli UPPs. With a variety of different ratios of enzyme to substrate and FPP to IPP in the presence or absence of Triton, different product distributions were found. In the presence of excess FPP, the intermediates (C(25)-C(50)) accumulated. Under a condition with enzyme and FPP in excess of IPP, instead of C(20)-geranylgeranyl pyrophosphate, C(20), C(25), and C(30) were the major products. The UPPs steady-state k(cat) value (2.5 s(-1)) in the presence of 0.1% Triton was 190-fold larger than in the absence of Triton (0.013 s(-1)). The k(cat) value matched the rate constant of each IPP condensation obtained from the enzyme single-turnover experiments. This suggested that the IPP condensation rather than product release was the rate-limiting step in the presence of Triton. In the absence of Triton, the intermediates formed and disappeared in a similar manner under enzyme single turnover in contrast to the slow steady-state rate, which indicated a step after product generation was rate limiting. This was further supported by a burst product formation. Judging from the accumulation level of C(55), C(60), and C(65), their dissociation from the enzyme cannot be too slow and an even slower enzyme conformational change with a rate of 0.001 s(-1) might govern the UPPs reaction rate under the steady-state condition in the absence of Triton.

Novel designs for sampled grating-based multiplexers demultiplexers

Novel multiplexers-demultiplexers for dense wavelength-division multiplexing systems that use interleaved sampled gratings are presented. It is shown that, with the appropriate design, configurations ranging from hybrid to add-drop as well as all-grating-based multiplexers can easily be realized.

Mixed quantum mechanical/molecular mechanical simulations of chemical reactions in solution and in enzymes by the classical trajectory mapping approach

We present a practical hybrid quantum mechanical/molecular mechanical approach to study chemical reactions in solution and in enzymes. In this method, referred to as the "Classical Trajectory Mapping" method, trajectories are calculated on the classical potential surfaces and, by using the classical surfaces as a reference state for the actual quantum mechanical ground state potential, the free energy profile of the chemical reaction is obtained by the free energy perturbation technique. This method was applied to proton-transfer reactions both in aqueous solution and in papain. The encouraging results indicate the applicability of our method to chemical reactions in the condensed phase and the biological systems.

Analysis of binding of cobra cardiotoxins to heparin reveals a new beta-sheet heparin-binding structural motif

Heparin and heparan sulfate have recently been shown to bind to snake cardiotoxin (CTX) and to potentiate its penetration into phospholipid monolayer under physiological ionic conditions. Herein we analyze the heparin-binding domain of CTX using 10 CTXs from Taiwan and African cobra venom. We also performed computer modeling to obtain more information of the binding at molecular level. The results provide a molecular model for interaction of CTX-heparin complex where the cationic belt of the conserved residues on the concave surface of three finger beta-sheet polypeptides initiates ionic interaction with heparin-like molecules followed by specific binding of Lys residues near the tip of loop 2 of CTX. The dissociation constants of CTXs differ by as much as 4 orders of magnitude, ranging from approximately 140 microM for toxin gamma to approximately 20 nM for CTX M3, depending on the presence of Lys residues near the tip of loop 2. High affinity heparin binding becomes possible due to the presence of Arg-28, Lys-33, or the so-called consensus heparin binding sequence of XKKXXXKRX near the tip of the loop. The well defined three-finger loop structure of CTX provides an interesting template for the design of high affinity heparin-binding polypeptides with beta-sheet structure. The finding that several cobra CTXs and phospholipase A2 bind to heparin with different affinity may provide information on the synergistic action of the two venom proteins.

[Polydipsia and water intoxication in schizophrenia patients: report of two cases]

This report describes two cases of schizophrenia inpatients with polydipsia, intermittent hyponatremia, and water intoxication. Case 1, a 38 year-old male, developed polydipsia after seven years duration of schizophrenia, with a daily intake of water of more than 10 liters as a result of auditory hallucination suggestion. Nocturnal hyponatremia, agitation and exacerbation of psychosis were noted during admission. After 12 treatments of electroconvulsive therapy, the symptoms of psychosis and polydipsia declined. Case 2, a 42 year-old male, had also been a case of schizophrenia for about twenty years, and developed polydipsia with more than 5 liters of daily water intake in a chronic psychiatric hospital for a period of 5 years schizophrenia. He claimed that he enjoyed the pleasure of drinking water. The symptom of water intoxication had been noted intermittently in the past year, leading to at least two seizures. Finally the patient was transferred to our ward due to agitated mood, self-destructive behavior, consciousness loss, and motor weakness. The clinical features, differential diagnosis and treatment concept of polydipsia and water intoxication were also discussed in context.