[Feasibility and safety of transseptal transcatheter mitral valve replacement for severe mitral regurgitation]

A prospective, single-center, single-arm, and open-design study was performed to evaluate the feasibility and safety of transseptal transcatheter mitral valve replacement in the treatment of severe mitral regurgitation. Patients with symptomatic moderate-severe or severe mitral regurgitation at high-surgical risk and anatomically appropriate for the HighLife transseptal mitral valve replacement (TSMVR) system in West China Hospital, Sichuan University from December 2021 to August 2022 were enrolled. Four patients (1 male and 3 females) with severe mitral regurgitation were included, with a median age of 68.5 (64.0-77.0) years and a median Society of Thoracic Surgeons (STS) score of 8.1% (6.4%-8.9%). Technical success was achieved in all the patients. There was no residual mitral regurgitation, paravalvular leakage, or left ventricular outflow tract obstruction. Three major cardiovascular and cerebrovascular adverse events occurred within 30 days after the procedure, including ventricular tachycardia, iatrogenic atrial septal defect closure, and heart failure readmission. The current study preliminarily demonstrates that transcatheter mitral valve replacement using the HighLife system via the transseptal approach for severe mitral regurgitation is feasible and relatively safe.

[Analysis of the characteristics of delayed high-degree atrioventricular block after transcatheter aortic valve replacement]

Objective: To investigate the characteristics of delayed high-degree atrioventricular block (DHAVB) after transcatheter aortic valve replacement (TAVR). Methods: One hundred and seventy-six patients who underwent TAVR with a self-extending valve between May 2014 and November 2018 in the Department of Cardiology, West China Hospital of Sichuan University, were retrospectively enrolled, including 101 males and 75 females, aged 54-92 (73±7) years, and the data were collected during the perioperative and 30 d follow-up periods. According to the occurrence of HAVB after TAVR, 160 patients were divided into no-HAVB group (145 cases) and DHAVB group (15 cases), except 16 patients who developed HAVB within 2 days after TAVR. Baseline data, intraoperative data, and immediate postoperative ECG characteristics were compared between the two groups, and logistic regression models were used to analyze the factors associated with the occurrence of DHAVB after TAVR. Meanwhile, the diagnostic ability of the postoperative routine 12-lead ECG for DHAVB was evaluated using the ambulatory ECG findings as the standard diagnosis. Results: The incidence of DHAVB was 8.5% (15/176) and occurred at 5 (4, 6) d. Compared with the no-HAVB group. The percentage of no new conduction block on the immediate postoperative ECG was lower in the DHAVB group [6/15 vs 66.2%(96/145), P=0.044], and the percentage of new right bundle branch block on the immediate postoperative ECG was higher [4/15 vs 3.4%(5/145), P=0.002]. Multifactorial logistic regression analysis showed that right bundle branch block on the immediate postoperative ECG [OR (95%CI):6.60 (1.26-34.47), P=0.025] was an associated factor for the development of DHAVB after TAVR. The specificity of postoperative routine 12-lead ECG for the diagnosis of DHAVB was 100% (145/145), but the sensitivity was only 73.3% (11/15). Conclusions: The incidence of DHAVB after TAVR is also high in Chinese. The immediate postoperative ECG characteristics of patients who underwent TAVR are associated with DHAVB events, and applying these characteristics to risk stratify patients may optimize the management of DHAVB after TAVR.

Selection of different reaction channels in 6Li induced fusion reaction by a powerful combination of a charged particle array and a high-resolution gamma spectrometer

Investigation of the breakup and transfer effect of weakly bound nuclei on the fusion process has been an interesting research topic in the past several years. In comparison with radioactive ion beam (RIB), the beam intensities of stable weakly bound nuclei such as 6,7Li and 9Be, which have significant breakup probability, are orders of magnitude higher. Precise fusion measurements induced by these nuclei have already been performed. However, the conclusion of reaction dynamics was not clear and has contradiction. In order to have a proper understanding of the influence of breakup and transfer of weakly bound projectiles on the fusion process, the 6Li+89Y experiment with incident energies of 22 MeV and 34 MeV was performed on Galileo array in combination with Si-ball EUCLIDES at Legnaro National Laboratory (LNL) in Italy. Using the coincidence by the charged particles and γ-rays, the different reaction channels can be clearly identified.

Effect of Trap Color, Height, and Orientation on the Capture of Yellow and Stick Tea Thrips (Thysanoptera: Thripidae) and Nontarget Insects in Tea Gardens

Two thrips species-the yellow tea thrips ( Scirtothrips dorsalis Hood) and the stick tea thrips ( Dendrothrips minowai Priesner)-are serious pests affecting tea plants in southern China. Although the stick tea thrips is primarily restricted to southern China, the yellow tea thrips is gradually proliferating worldwide. Colored sticky card traps may be useful for monitoring and capturing these species, but a systematic analysis has not been conducted to identify the most effective trap color, height, and orientation. We performed indoor experiments using an orthogonal experimental design, as well as field tests in tea gardens, to identify the color most attractive to the two thrips species. Field tests were then conducted using color-optimized traps-lawngreen (RGB: 124, 252, 0) for yellow thrips and lime (RGB: 0, 255, 0) for stick tea thrips-to determine the most effective trap height and orientation. The greatest numbers of both yellow and stick tea thrips were captured on traps positioned 0-20 cm above the tea canopy in an east-west orientation. We also evaluated the performance of the color-optimized sticky card traps compared with commercially available yellow ones. Significantly more yellow and stick tea thrips and fewer natural enemies were captured on the color-optimized traps than on commercial ones. Although additional research is needed to explain the responses of the two different species and to increase trap effectiveness, our findings should assist in the control of these harmful insects.

A fatal case of hepatic failure possibly induced by nitrosofenfluramine: a case report

A 42-year-old female developed fulminant hepatic failure after having ingested an undetermined quantity of a herbal product over a period of approximately four months prior to the onset of her illness. Clinically, the cause of liver failure was assessed to be drug-induced and she eventually underwent total hepatectomy, with porto-caval shunting, in anticipation of a living-unrelated liver transplant. Unfortunately, her condition deteriorated and she died less than 48 hours post-operatively, approximately three weeks post-admission. An autopsy showed that the subject was deeply jaundiced and severely obese (BMI: 47.1 kg m(-2)), with evidence of diffuse haemorrhage, including the presence of 1.35 l of blood in the peritoneal cavity. The liver had been removed and was later recovered as a formalin-fixed specimen which was markedly contracted, comprising multiple micronodules interspersed with extensive areas of dense fibrotic tissue. Histologically, there was massive necrosis of the hepatic parenchyma, such that the residual hepatocytes were disposed as nodules displaying variable cellular regeneration and ballooning degeneration, attended by florid ductal proliferation and mixed inflammatory infiltrates. Infective, autoimmune, metabolic, vascular, neoplastic and most other natural causes of massive hepatocellular necrosis were effectively excluded. Analysis of the post-mortem blood samples yielded fluconazole, metronidazole, frusemide, lignocaine and tramadol, (therapeutic agents administered to the patient during her last illness). Subsequent analysis of the residual capsules revealed that they were adulterated by fenfluramine, N-nitrosofenfluramine (1.3-1.6 mg per capsule), nicotinamide (13.3-15.6 mg per capsule) and thyroid extract. None of the herbal ingredients is currently known to be hepatotoxic and much the same applies to fenfluramine, nicotinamide (except when taken in mega-doses) and thyroid extract. However, as nitrosamines are known to be variably hepatotoxic, it would be reasonable to surmise that, in the absence of a more plausible cause of liver damage, N-nitrosofenfluramine was the likely cause of massive hepatocellular necrosis in this instance.

[Effect of lower body negative pressure and rotating-table simulated push-pull effect in flight on cardiovascular function]

Objective. To explore the effect of push-pull effect (PPE) simulated by lower body negative pressure (LBNP) rotating-table, and observe the physiological responses to push-pull maneuver. Method. A special LBNP rotating-table was used to simulate the push-pull maneuver. 8 healthy adults participated randomly in two experiments. One was simulated PPE test, which include a series of head-up stand (HUT, +1 Gz) for 1 min, then in head-down stand (HDT, -1 Gz) for 30 s and again in HUT combining LBNP (-50 mmHg) for 10 min. The other one was control test, which only consists of HUT combining LBNP (-50 mmHg) for 10 min. Changes of heart rate (HR), blood pressure (BP), basic impedance (Z0) , stroke output (SO) , cardiac output (CO) and total peripheral resistance (TPR) were monitored by electrical impedance instrument during the experiment. Result. During simulated PPE experiment, 3 subjects presented presyncopal symptoms, with average standing time of 8.99 +/- 1.47 min, while during control test, all the subjects completed HUT combining LBNP for 10 min. In simulated PPE experiment, as compared with HUT (control), HR, Z0 during HDT were significantly lowered, while SV and CO were increased significantly. During HUT + LBNP, HR, Z0 and TPR were significantly higher, while SV and CO were significantly lower than that of control and HDT. SBP was increased significantly than control value when "HUT + LBNP" started, but during the whole process of "HUT + LBNP ", it became significantly lowered. In control experiment, the above mentioned indexes showed the same trend of as change compared with the control, however, the percentage of the change was lower than simulated PPE test, the change percentage in HR was not including. Conclusion. After headstand, head-up stand combining LBNP caused cardiovascular function descends, the degree was larger than simple head-up stand combining LBNP. LBNP rotating-table can be used to simulated push-pull effect.

[Variety of lower body negative pressure tolerance after different repeated lower body negative pressure exposures]

AIM

To investigate the variety of lower body negative pressure (LBNP) tolerance after different repeated lower body negative pressure exposures and select the best one.

METHODS

27 health male subjects were divided into 3 groups at random and exposed in 8 consecutive daily LBNP of -5.33 kPa 8 min (group A), -6.67 kPa 4 min (group B), - 6.67 kPa 8 min (group C) respectively. Pre- and post- exposures, lower body negative pressure tolerance were measured. HR and BP are recorded during exposures.

RESULTS

As compared with pre-exposure, Cumulative Stress Index (CSI) and During Negative Pressure(DNP) of group C are increased significantly after repeated LBNP exposures. During exposures HR increased and SBP decreased significantly. DBP did not change.

CONCLUSION

LBNP tolerance were increased significantly after eight consecutive daily LBNP (- 6.67kPa) exposures. Among the three modes, this is the best one.

[Changes of cerebral blood flow during 21 d head-down tilt bed rest and the effect of lower body negative pressure during the last week]

Objective. To investigate the changes of cerebral blood flow (CBF) during 21 d head-down tilt (HDT) bed rest and the effect of lower body negative pressure (LBNP) in the last week. Method. Twelve healthy male subjects were randomly divided into control and LBNP groups, with 6 in each group. All of them were exposed to -6 degrees HDT for 21 d. The LBNP group received -4.0 kPa LBNP training 1 h/d in the last week of HDT while the control group did not. CBF and cerebral vascular resistance were measured by rheoencephalogram in pre-HDT, day 3, 10 and 21 of HDT. Result. In control group, left cerebral I quadrant area and inrush velocity decreased significantly during HDT, and left cerebral delta Gy wave crest height decreased significantly, whereas left cerebral resistance index increased significantly on day 3 and 21 of HDT as compared to those of pre-HDT. In LBNP group, left cerebral I quadrant area decreased significantly, and left cerebral delta Gy wave crest height and inrush velocity tended to decrease on day 3 and 21 of HDT, whereas left cerebral resistance index increased significantly during HDT as compared to those of pre-HDT. There were no significant differences between above indexes in control group and LBNP group. Conclusion. It is suggested that 21 d HDT may increase cerebral vascular resistance and decrease CBF, which can not be prevented by LBNP training in the last week of 21 d HDT.

[Changes of cardiac function during 21 d head-down tilt bed rest and the effect of lower body negative pressure in the last week]

OBJECTIVE

To investigate the change of cardiac function during 21 d head-down tilt (HDT) bed rest and the effect of lower body negative pressure (LBNP) in the last week in human.

METHOD

12 healthy male served as subjects which were randomly divided into control and LBNP groups, with 6 in each group. All of them were exposed to -6 degrees HDT for 21 d. The LBNP group received -4.0 kPa LBNP training 1 h/d in the last week of the test. The cardiac pump function and cardiac systole function were measured before, during and after HDT.

RESULT

Cardiac output, cardiac index and stroke volume decreased significantly, whereas total peripheral resistance, pre-ejection period (PEP), isovolumetric contraction time/left ventricular ejection time (LVET) and PEP/LVET increased significantly during HDT in both control and LBNP groups, compared to pre-HDT values, and they returned to normal level on day 2 post HDT. PEP and PEP/LVET in LBNP group were significantly higher than those in control group on day 21 of HDT and day 2 post HDT.

CONCLUSION

The reduction of cardiac pump function and cardiac systole function induced by 21 d HDT could not be prevented by LBNP training in the last week of 21 d HDT.

Changes of human cerebral bottom arterial hemodynamics during 21 d head-down tilt (-6 degrees) bed-rest

OBJECTIVE

To investigate the change of human cerebral bottom arterial hemodynamics during 21 d simulated weightlessness.

METHOD

21 d -6 degrees head-down tilt bed rest (HDT) were used to simulate weightlessness. 6 healthy male, aged 24.8 +/- 6.1 served as subjects. Systolic blood velocity (Vs), diastolic blood velocity (Vd), mean blood velocity (Vm), pulsatility index (PI), resistance index (RI) and other indices of middle cerebral arteries (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA) were measured by transcranial ultrasound Doppler before HDT and on day 0 (D0), 1, 3, 7, 10, 21 of HDT. HUT +75 degrees 20 min orthostatic tolerance tests were done on day -1, 10, and 21 of HDT.

RESULT

During HUT +75 degrees 20 min orthostatic tolerance test on day 10 and 21 of HDT, the average standing time were shorter than that of the pre-HDT values (P<0.05). On day 3 and 21 of HDT, Vs of right MCA reduced significantly than pre-HDT (P<0.05 or P<0.01). On day 1, 3, 7, 10 and 21 of HDT, Vs of right MCA were obviously lower than that on D0 (P<0.05 or P<0.01). Left MCA Vs on D0 increased significantly than that of pre-HDT (P<0.05), and both were significantly higher than those of the 3rd day of HDT (P<0.01). Right MCA Vm on the 3rd and 21st day of HDT were significantly lower than those pre-HDT and D0 (P<0.05 or P<0.01). On day 10 of HDT, Vm of right MCA were significantly reduced than that on D0 (P<0.05). Both MCA bilateral velocity difference (right Vm-left Vm) on the 3rd, 10th, 21st day of HDT, and MCA inter-hemispheric asymmetry index on the 10th, 21st day of HDT were significantly lower than that of pre-HDT (P<0.05 or P<0.01).

CONCLUSION

21 d HDT bed-rest decreased orthostatic tolerance, Vs of both side MCA, and Vm of right MCA. Lower Vs of both side MCA and the inter-hemispheric asymmetry of MCA during HDT maybe responsible, in part, for the increased risk of orthostatic intolerance.

Role of PTCH and p53 genes in early-onset basal cell carcinoma

Basal cell carcinoma (BCC) is the most common skin cancer in the Western world. Ultraviolet (UV) exposure, race, age, gender, and decreased DNA repair capacity are known risk factors for the development of BCC. Of these, UVB irradiation from sunlight is the most significant risk factor. The incidence of sporadic BCC increases in individuals older than age 55, with the greatest incidence reported in individuals who are older than 70, and is rare in individuals who are younger than 30. In this study, we analyzed 24 BCC samples from individuals who had BCC diagnosed by the age of 30. Fifteen single-stranded conformation polymorphism variants in the PTCH gene were identified in 13 BCC samples. Sequence analysis of these single-stranded conformation polymorphism variants revealed 13 single nucleotide changes, one AT insertion, and one 15-bp deletion. Most of these nucleotide changes (nine of 15) were predicted to result in truncated PTCH proteins. Fifteen p53 mutations were also found in 11 of the 24 BCC samples. Thirty-three percent (five of 15) and 60% (nine of 15) of the nucleotide changes in the PTCH and p53 genes, respectively, were UV-specific C-->T and CC-->TT nucleotide changes. Our data demonstrate that the p53 and PTCH genes are both implicated in the development of early-onset BCC. The identification of UV-specific nucleotide changes in both tumor suppressor genes suggests that UV exposure is an important risk factor in early onset of BCC.

[Effects of repeated low body negative pressure (LBNP) exposures on LBNP tolerance]

OBJECTIVE

To investigate variation of low body negative pressure (LBNP) tolerance and the relationship with change of heart function after repeated LBNP exposures.

METHOD

Ten healthy subjects were exposed to eight min consecutive daily LBNP (-50 mmHg). Before and after this exposures, tolerance to LBNP was determined by a cumulative stress index (CSI) and duration of negative pressure (DNP).

RESULT

The pre- and post repeated exposure values of CSI and DNP were 1058 +/- 216 s, 1354 +/- 233 s and 45833 +/- 12546 s mmHg, 63433 +/- 13458 s mmHg, respectively. It showed that both were increased significantly (P<0.05), and the heart function was showed to have a tendency of being enhanced.

CONCLUSION

It suggested that LBNP tolerance increased after repeated exposures, which might be achieved via strengthening of ventricular contractivity, decreasing the compliance of peripheral vascular, the hypotensive [correction of hypotentive] reflex compensatory mechanisms becoming more effective, and increasing arterial blood pressure on heart level.

[Effects of 24 h -6 degrees head-down tilt bed-rest on cardiovascular function and response to orthostatic stress]

Objective. To investigate the effects of 24 h -6 degrees head-down tilt bed-rest (HDT) on cardiovascular function and response to orthostatic stress. Method. -6 degrees head-down tilt bed rest for 24 h in 6 healthy males, aged 22-23, were observed. The changes of cardiac function were observed by electrical impedance instrument before and at 0th, 6th, 12th, 18th and 24th hour of HDT, and blood pressure were recorded and urine were collected. The changes of cardiovascular response to head up tilt (HUT 90 degrees, 10 min) before and post HDT were recorded. Result. During HDT, HR reduced significantly than that of pre-HDT (standing). HR at 6th, 12th, and 18th hour of HDT reduced significantly than that at 0th hour of HDT. Stroke output (SO) and stroke index (SI) [correction of CI] at 0th, 6th, 12th, and 24th hour of HDT were higher than pre-HDT value. Cardiac output (CO) and cardiac index (CI) at 18th hour of HDT were significantly lower than those at 0 h of HDT. Total peripheral resistance (TPR) at 18th hour of HDT were higher than that at 0th of HDT. During HUT before and post HDT, HR, MBP, TPR were significantly increased, SO, [correction of SV] SI, CO and CI were significantly reduced. DBP were significantly increased and PP were reduced significantly during HUT post-HDT. Hourly average value of urine during 0-4 h were higher than those during 4-12 h and 12-24 h. Conclusion. 24 h -6 degrees head-down tilt bed rest has significant effects on cardiovascular function and response to HUT in humans.

Mutation report: identification of a germline mutation in keratin 17 in a family with pachyonychia congenita type 2

Pachyonychia congenita type 2 (PC-2), also known as Jackson-Lawler type PC, is an autosomal dominant disorder characterized by hypertrophic nail dystrophy associated with focal keratoderma and multiple pilosebaceous cysts. It has been demonstrated that PC-2 is associated with germline mutations in the keratin 17 (K17) gene and in its expression partner keratin 6b. In this report, we describe a novel germline mutation in K17, M88T, in a family with PC-2.

[Effect of extremity cuffs as a countermeasure against the cardiovascular deconditioning during 21 d head-down bedrest]

OBJECTIVE

To affirm the protective effect of inflated cuffs.

METHOD

The protective effect against the cardiovascular deconditioning of inflated cuffs on the upper parts of thighs and arms during the 1st through 10th days of 21 d bedrest has been reported previously. The effect of the cuffs during the rest of the 21 d bedrest were studied in this paper. Five subjects in cuffs group whose orthostatic tolerance were well maintained continued bed rest for 7 d without inflated cuffs. For the last 4 days of this period, inflated cuffs were again applied. Orthostatic tolerance of subjects in cuffs group with and without cuffs were measured.

RESULT

Two of the five subjects suffered orthostatic intolerance on the 17th day. No sign of orthostatic intolerance were observed by the end of bedrest.

CONCLUSION

(1) the cardiovascular deconditioning developed when inflated cuffs were not used, and (2) the use of inflated cuffs for 4 d improves the orthostatic tolerance.

[Mechanisms and detection of G-induced loss of consciousness]

High sustained +Gz acceleration induced loss of consciousness (G-LOC) is the main factor that causes flying accident. This paper reviewed the mechanisms and its physiological detection. During slow onset rate (SOR) acceleration, cerebral ischemia/hypoxia are the mechanisms of G-LOC, during rapid onset rate (ROR) acceleration, G-LOC might be related to mechanical intracranial hypertension, but the direct experimental data were lacking. Arterial blood pressure of eye level and cerebral oxygen saturation are important among the physiological indices of G-LOC detection.

[Variation of several volume regulating hormones during 21 d - 6 degrees head-down bed rest]

Objective To investigate variations of plasma renin activity, a prostaglandin I2 (PGI2) during 21 d -6 degrees head-down tilt (HDT) with and without lower body negative pressure (LBNP).

METHOD

-6 degrees head-down tilt for 21 d were used to simulate weightlessness. 12 healthy male, aged 23.7 +/- 5.0, were equally and randomly divided into control group (CON) and LBNP group. The latter subjected to LBNP (-30 mm Hg, 1 h/d) in the last week of HDT. Samples of plasma were taken before HDT and on the 2nd, 4th, 11th and 22nd day during HDT.

RESULT

Compare to control levels, Ald declined significantly on the 2nd (CON -30%, P < 0. 05; V. S. LBNP -38%, P < 0.01), and increased significantly on the 11th day (CON +30%, P < 0.05; LBNP +48%, P < 0.01). PRA reached peak value on the 4th day (P < 0.05), and declined to below the control level on the 22nd day. PGI2 increased constantly during HDT, and increased significantly on the 22nd day (CON P < 0.01), 11th, 22nd (LBNP P < 0.05). No apparent difference was found between groups after LBNP concerning PRA and Ald; and PGI2 didn't increase further in LBNP group. Conclusion HDT induced a timely increasing in PRA and Ald, constant increasing in PGI2.

[Computer simulation of cardiovascular response to lower body negative pressure]

OBJECTIVE

To simulate the cardiovascular response to lower body negative pressure (LBNP).

METHOD

A computer model was developed. It had 7 subparts: the redistribution of blood, the filling of left ventricle, left ventricle, peripheral circulation, control of heart rate, control of peripheral resistance and control of venous tone. The heart rate and venous tone were controlled by high-pressure receptor baroreflex, while the peripheral resistance was controlled by high- and low-pressure receptor baroreflexes.

RESULT

With the help of the model, cardiovascular response to LBNP up to -10.64 kPa (-80 mmHg) were simulated, including the changes of systolic blood pressure, mean blood pressure, heart rate and cardiac output. The time-dependent response to a LBNP profile was also simulated. The simulation results coincided well with human experiments.

CONCLUSION

The model is valid and can accurately reproduce the short-term hemodynamic response to LBNP.

PTEN/MMAC1 mutations in hepatocellular carcinomas

Mutations in the PTEN/MMAC1 gene have been identified in several types of human cancers and cancer cell lines, including brain, endometrial, prostate, breast, thyroid, and melanoma. In this study, we screened a total of 96 hepatocellular carcinoma (HCC) samples from Taiwan, where HCC is the leading cancer in males and third leading cancer in females, for mutations in the PTEN/MMAC1 gene. Complete sequence analysis of these samples demonstrated a missense mutation in exon 5 (K144I) and exon 7 (V255A) from HCC samples B6-21 and B6-2, respectively. A putative splice site mutation was also detected in intron 3 from sample B6-2. Both B6-21 and B6-2 were previously shown to contain missense mutations in the coding sequences of the p53 gene. Functional studies with the two missense mutations demonstrated that while mutation V255A in exon 7 resulted in a loss of phosphatase activity, mutation K144I in exon 5 retained its phosphatase activity. Additionally, we identified a silent mutation (P96P) in exon 5 of the PTEN/MMAC1 gene from HCC sample B6-22. These data provide the first evidence that the PTEN/MMAC1 gene is mutated in a subset of HCC samples.

[Countermeasuring effect of lower body negative pressure against orthostatic intolerance induced by 21 d -6 degrees head down tilt in humans]

Objective. To investigate whether LBNP during 21 d -6 degrees head-down tilt (HDT) would modify orthostatic tolerance. Method. 12 healthy males, age 23.7 +/- 5.0, were exposed to -6 degrees HDT for 21 d. 6 of them received -4.0 kPa LBNP sessions for 1 h/d from 15th day to 21st day of HDT. The other 6 served as control. HUT + 75 degrees, 20 min orthostatic tolerance test were done before, on day 10 and on day 21 of HDT. Result. During HUT + 75 degrees, 20 min orthostatic tolerance test on day 10 of HDT, 5 subjects of the control group and 4 of the LBNP group presented presyncopal or syncopal signs and symptoms, the average standing time of both groups were shorter than those of the pre-HDT (p<0.05). During HUT + 75 degrees, 20 min orthostatic tolerance test on day 21 of HDT, 5 subjects of the control group and one subject of the LBNP group presented presyncopal or syncopal signs and symptoms, the average standing time of control group reduced significantly as compared with those of pre-HDT(P<0.05), also significantly shorter than those of LBNP group (P<0.05). Conclusion. The present study clearly shows that the use of LBNP could alleviate the bed rest-induced orthostatic intolerance.

Repression of transactivation of the retinoic acid receptor beta2 promoter in human breast cancer cells

In previous studies, we have shown that the expression of retinoic acid receptor beta2 (RARbeta2) is altered in certain breast cancer cell lines. To investigate the mechanism responsible for this change, we studied in detail the RARbeta2 promoter in cell lines which demonstrated altered expression and compared these results to cell lines in which RARbeta2 was expressed normally. Direct DNA sequencing failed to identify alterations in the sequences of the known response elements in the cell lines manifesting altered expression patterns. By contrast, electrophoretic mobility shift studies of the proteins binding to these response elements demonstrated striking differences in the cells in which expression was altered, when compared to patterns seen in normal cells. Moreover, transient transfection studies using constructs of the RARbeta2 promoter demonstrated an absence of transactivation in the lines in which the expression of this gene was altered. These data suggest that the mechanism responsible for loss of induction of RARbeta2 in breast tumor cells is, at least in part, transcriptional repression.

Infrared photorefractive polymers and their applications for imaging

Photorefractive polymers with high diffraction efficiency in the visible and near-infrared regions of the electromagnetic spectrum have been developed. These polymers, which have a large dynamic range because of their high orientational birefringence, incorporate a dye designed to have a large dipole moment and a high linear polarizability anisotropy. Such polymers have enabled demonstrations of imaging through scattering media, using a holographic time-gating technique at a wavelength that is compatible with the transparency of biological tissues and with the emission of low-cost semiconductor laser diodes.

Acidic and neutral drugs screen in blood with quantitation using microbore high-performance liquid chromatography-diode array detection and capillary gas chromatography-flame ionization detection

Blood previously acidified with aqueous saturated ammonium chloride solution was extracted with ethyl acetate. The dried extract was subjected to acetonitrile-hexane partition. The acetonitrile portion was analysed for the presence of acidic and neutral drugs by HPLC-DAD (200 mm x 2.1 mm I.D. microbore ODS-Hypersil column) and GC-FID (25 m narrow-bore x 0.25 mm I.D. HP-5 column with 0.33 micron film thickness). The protocol was found to be suitable for both clinical toxicology (including emergency toxicology) and postmortem toxicology. At least 66 drugs of interest were unequivocally identified by RRTs (HPLC) and UV spectra (DAD) match while another 12 were unequivocally identified by double RRTs match (HPLC and GC). Quantitation was facilitated by incorporating calibration blood standards in each assay batch. The five drugs most commonly encountered in clinical blood specimens (1150 cases) were: paracetamol (47.4% of the cases); chlormezanone (6.6%), theophylline (1.74%), naproxen (1.65%) and mefenamic acid (1.56%). The following drugs were detected in toxicologically significant quantities in postmortem blood specimens (245 cases): phenobarbitone (1.22% of the cases), naproxen (0.82%), chlormezanone (0.82%), theophylline (0.82%), carbamazepine (0.41%) and paracetamol (0.41%).

Short-term safety of live attenuated Japanese encephalitis vaccine (SA14-14-2): results of a randomized trial with 26,239 subjects

The short-term safety of an effective and inexpensive new live attenuated Japanese encephalitis vaccine (SA14-14-2) was studied in a randomized trial, using block randomization. Of 26,239 children who were enrolled, half received the vaccine and half served as controls. Subjects were prospectively followed for 30 days for severe adverse events, such as encephalitis, meningitis, and "all-cause" hospitalization. No cases of encephalitis or meningitis occurred in either group. The upper 95% confidence limit for adverse events not occurring among subjects receiving their first dose was 4.1/10,000. Risk ratios and 95% confidence intervals for other adverse events were 0.70 (0.43-1.15) for all-cause hospitalization, 0.91 (0.37-2.22) for seizure, and 0.79 (0.56-1.11) for fever lasting > or = 3 days. These data attest to the short-term safety of the SA14-14-2 virus strain and the hamster kidney cell substrate.

Expression of retinoid X receptors in human dermal fibroblasts

Retinoic acid (RA) is known to exert profound effects on growth and differentiation in human dermal fibroblasts. In the observations presented here, we examined the regulation of expression of members of the RXR multigene family in human dermal fibroblasts. We showed that the messenger RNAs for both RXR alpha and RXR beta are expressed in human fibroblasts, but that the messenger RNA for RXR gamma is not detectable in these cells. Electrophoretic mobility shift studies of binding to the beta 2RARE in human dermal fibroblasts demonstrated that a single complex binds to beta 2RARE in the absence of RA. Stimulating cells with all-trans RA induced a second complex. An antibody to the RXR beta protein supershifted both complexes, while an antibody to the RXR alpha S/B protein had no effect on the binding. These data demonstrate that RXR beta plays an important role in retinoid-regulated signal transduction pathways in human dermal fibroblasts and the regulation of expression of the RXR gene family is different from that of the RAR gene family.

Analysis of recombinant human tumor necrosis factor beta by capillary electrophoresis

Capillary electrophoresis was used for the analysis of recombinant human tumor necrosis factor beta (rhTNF-beta). Reproducible separation of the protein could be achieved in Polybrene-coated capillaries. Optimum conditions for separation were achieved with a pH 4.5 sodium acetate buffer. Besides Polybrene-coated capillaries, other commercially available column and column-coating reagents were also examined for the separation of rhTNF-beta. Capillary electrophoresis was found to be a potentially useful method for product analysis and process monitoring in recombinant-DNA technology.

Optimization of the gradient HPLC separation of selected phthalates using the overlapping resolution mapping technique

Optimization procedures for the reversed-phase separations of six phthalates using the isoselective multisolvent gradient elution (IMGE) system are described. A systematic experimental design has been employed to gather retention data on the compounds in a mixture. The data were then fitted into a second-order polynomial equation and an overlapping resolution mapping (ORM) technique of data analysis was subsequently used to establish the optimum solvent mixture for the highest resolution of all adjacent peaks in the chromatogram.

[Diagnosis of congenital CMV infection by specific CMV IgM antibody in cord serum with ELISA]

Cytomegalovirus IgM (CMV IgM) antibodies of 582 cord sera from 6 hospitals in Chengdu were detected by direct ELISA and indirect ELISA. Twenty-seven cases with CMV IgM antibody positive were detected from 582 cord sera. Twenty-five and 15 cases were found to have CMV IgM antibody by direct ELISA and indirect ELISA, respectively (P greater than 0.05). Indirect ELISA for detection CMV IgM antibody was only interfered by high concentration of CMV IgG and rheumatoid factor. Children with CMV IgM antibody positive were followed-up to 5-6 months. Hearing loss was detected by impedance audiology in only 2 cases. But the other physical and mental examinations were normal. The result showed that the prevalence of congenital CMV infection is 4.6% in our study and direct ELISA method is more specific and sensitive than indirect ELISA method to detect CMV IgM antibody in cord serum.