Influence of vestibulo-sympathetic reflex on muscle sympathetic outflow during head-down tilt

To clarify the response of muscle sympathetic nerve activity (MSNA) to static stimulation of otolith organs in a craniocaudal direction (+Gz) in humans, we examined the effect of otolith stimulation on MSNA without changing the effect of cardiopulmonary baroreceptors using a 6-8.5 degrees head-down tilt (HDT) and lower body negative pressure (LBNP) device. Before the study, we established that 6-8.5 degrees HDT with 10 mmHg LBNP caused a fluid shift to the degree that the thoracic impedance was the same as the supine position without LBNP. Subjects were young male volunteers aged 22.1 +/- 3.8 years who gave informed consent. MSNA was recorded from the tibial nerve by microneurography simultaneously with heart rate (ECG), thoracic fluid volume (impedance method), and blood pressure (tonometric method). During 6-8.5 degrees HDT with 10 mmHg LBNP, MSNA was suppressed slightly without significantly changing heart rate, thoracic impedance, or mean arterial blood pressure. The results suggest that the sympathosuppression was related not to the result of cardiopulmonary [correction of cardioplumonary] loading but to the -Gz change (caudocranial direction [correction of dirction]) of 0.1 G. It is estimated that the vestibulo-sympathetic reflex may suppress sympathetic outflow to muscles in humans.

Effect of sodium nitroprusside on hemodynamics of corpus cavernosum in Chinese

AIM

To study the effect of sodium nitroprusside (SNP) on the hemodynamics of corpus cavernosum in Chinese men with erectile dysfunction (ED).

METHODS

In 68 ED patients receiving intracavernous injection (ICI) of SNP, the cavernous hemodynamics were studied by Doppler ultrasonography.

RESULTS

The peak flow velocity (PFV), the artery diameter (Ad), the mean velocity of arterial blood (MV) and the vein diameter (Vd) were significantly higher after ICI of SNP than before ICI, but the end diastolic velocity (EDV) did not change significantly.

CONCLUSION

The increase in Vd after SNP suggests that the venous outflow is not invariably decreased during penile erection.

Effect of simulated microgravity exposure on thermoregulatory control of sweating

The purpose of the present study was to investigate the alterations in thermoregulatory control following 14 days of head-down bed rest (HDBR). The threshold temperature for sweating onset and sweating sensitivity were determined from sweating rates on the chest and forearm, and tympanic temperature as an index of core temperature (Tc) in nine healthy males exposed to a 60-min heat stress with a water-perfused blanket before and after HDBR. The threshold temperature for sweating onset, that is, the Tc at which sweating began on the chest and forearm was 36.75 +/- 0.14 and 36.72 +/- 0.13 degrees C before HDBR, respectively. The value significantly increased to 37.05 +/- 0.09 (p<0.05) for the chest and 37.04 +/- 0.08 degrees C (p<0.05) for the forearm after HDBR. On the other hand, the sweating sensitivity which was indicated as a slope of the Tc-sweating rate relationship significantly decreased from 4.20 +/- 1.15 to 2.32 +/- 1.18 for the chest (p<0.05) and from 4.20 +/- 1.06 to 2.92 +/- 0.98 mg/min/cm2/degrees C for the forearm (p<0.05) after HDBR. These findings suggest that the heat-dissipatory function was attenuated after 14 days of HDBR.

Suicide attempts in an adolescent female twin sample

OBJECTIVE

To examine suicide attempts in an epidemiologically and genetically informative youth sample.

METHOD

3,416 Missouri female adolescent twins (85% participation rate) were interviewed from 1995 to 2000 with a telephone version of the Child Semi-Structured Assessment for the Genetics of Alcoholism, which includes a detailed suicidal behavior section. Mean age was 15.5 years at assessment.

RESULTS

At least one suicide attempt was reported by 4.2% of the subjects. First suicide attempts were all made before age 18 (and at a mean age of 13.6). Major depressive disorder, alcohol dependence, childhood physical abuse, social phobia, conduct disorder, and African-American ethnicity were the factors most associated with a suicide attempt history. Suicide attempt liability was familial, with genetic and shared environmental influences together accounting for 35% to 75% of the variance in risk. The twin/cotwin suicide attempt odds ratio was 5.6 (95% confidence interval [CI] 1.75-17.8) for monozygotic twins and 4.0 (95% CI 1.1 -14.7) for dizygotic twins after controlling for other psychiatric risk factors.

CONCLUSIONS

In women, the predisposition to attempt suicide seems usually to manifest itself first during adolescence. The data show that youth suicide attempts are familial and possibly influenced by genetic factors, even when controlling for other psychopathology.

Scattering and Internal Fields of a Microsphere that Contains a Saturable Absorber: Finite-Difference Time-Domain Simulations

Illumination intensities that are used to induce scattering and fluorescence in aerosols can be large enough to cause variations in the refractive index. Methods used to calculate the scattering from homogeneous particles may not be valid for these systems. We use the finite-difference time-domain method and an iterative technique to model scattering by microspheres that contain a saturable absorber. We illustrate this technique by calculating the scattering from spheres that contain tryptophan. We show the Mueller scattering matrices along with the internal intensity distributions for different incident intensities. The backscattering increases as the illumination intensity becomes large enough to saturate the absorption in regions of the sphere.

Static handgrip exercise modifies arterial baroreflex control of vascular sympathetic outflow in humans

To examine effects of static exercise on the arterial baroreflex control of vascular sympathetic nerve activity, 22 healthy male volunteers performed 2 min of static handgrip exercise at 30% of maximal voluntary force, followed by postexercise circulatory arrest (PE-CA). Microneurographic recording of muscle sympathetic nerve activity (MSNA) was made with simultaneous recording of arterial pressure (Portapres). The relationship between MSNA and diastolic arterial pressure was calculated for each condition and was defined as the arterial baroreflex function. There was a close relationship between MSNA and diastolic arterial pressure in each subject at rest and during static exercise and PE-CA. The slope of the relationship significantly increased by >300% during static exercise (P < 0.001), and the x-axis intercept (diastolic arterial pressure level) increased by 13 mmHg during exercise (P < 0.001). These alterations in the baroreflex relationship were completely maintained during PE-CA. It is concluded that static handgrip exercise is associated with a resetting of the operating range and an increase in the reflex gain of the arterial barorelex control of MSNA.

[Determination of paraoxonase activities in serum and HDL]

OBJECTIVE

[corrected] To establish a reliable method of determining the activity of paraoxonase(PON) in serum and high density lipoprotein(HDL).

METHODS

We used phenylacetate(PA) as substrate and investigated the hydrolysis of PA catalyzed by serum PON or HDL-PON. The PON activities were calculated from the velocities of reaction that had been determined by the increasing absorbance of product p-phenol within the first 5 minutes.

RESULTS

Through the studies on the effects of substrate concentration, pH, activator Ca2+, and inhibitor EDTA, we found the best conditions of reaction to be: substrate concentration 5 mmol/L, pH8.0, and Ca2+ concentration 2 mmol/L. And we established the method with good reproducibility and stability.

CONCLUSION

Under the above-stated conditions, it is reliable to determine the activity of paraoxonase in serum and HDL.

Effects of lower body positive pressure on muscle sympathetic nerve activity response to head-up tilt

The present study was performed to test the hypothesis that application of lower body positive pressure (LBPP) during orthostasis would reduce the baroreflex-mediated enhancement in sympathetic activity in humans. Eight healthy young men were exposed to a 70 degrees head-up tilt (HUT) on application of 30 mmHg LBPP. Muscle sympathetic nerve activity (MSNA) was microneurographically recorded from the tibial nerve, along with hemodynamic variables. We found that in the supine position with LBPP, MSNA remained unchanged (13.4 +/- 3.3 vs. 11.8 +/- 2.3 bursts/min, without vs. with LBPP; P > 0.05), mean arterial pressure was elevated, but arterial pulse pressure and heart rate did not alter. At 70 degrees HUT with LBPP, the enhanced MSNA response was reduced (33.8 +/- 5.0 vs. 22.5 +/- 2.2 bursts/min, without vs. with LBPP; P < 0.05), mean arterial pressure was higher, the decreased pulse pressure was restored, and the increased heart rate was attenuated. We conclude that the baroreflex-mediated enhancement in sympathetic activity during HUT was reduced by LBPP. Application of LBPP in HUT induced an obvious cephalad fluid shift as well as a restoration of arterial pulse pressure, which reduced the inhibition of the baroreceptors. However, the activation of the intramuscular mechanoreflexes produced by 30 mmHg LBPP might counteract the effects of baroreflexes.

[Studies on the pharmacokinetics and relative bioavailability of salbutamol aerosol in healthy volunteers]

AIM

To study the pharmacokinetics and relative bioavailability of salbutamol aerosol in healthy volunteers.

METHODS

An HPLC method for the determination of salbutamol in human plasma was improved. Ten healthy male subjects were enrolled. A randomized, two-way crossover, open design was adopted. After the subjects inhaled or orally administered salbutamol, fourteen blood samples were taken at predetermined time. The concentrations of salbutamol in plasma were determined by HPLC, and then assessed with PCNONLIN software to obtain the pharmacokinetic parameters and relative bioavailability of aerosol versus water solution.

RESULTS

The standard curve was linear over the range 0.2-20 ng.mL-1. The intra- and interassay RSDs were 7.01% and 2.10% at 0.4 ng.mL-1, 2.18% and 5.25% at 4.0 ng.mL-1 and 4.61% and 4.85% at 15.0 ng.mL-1. The recoveries were between 90% and 110%. The pharmacokinetics of salbutamol aersol was described well with a two-compartment model, and the parameters for salbutamol inhaled and orally administered were assessed as follows: Tmax were (0.22 +/- 0.07) h and (1.8 +/- 0.6) h, Cmax were (3.4 +/- 1.1) ng.mL-1 and (3.9 +/- 1.4) ng.mL-1, T1/2 beta were (4.5 +/- 1.5) h and (4.6 +/- 1.1) h, respectively. The AUC0-20 min (inhal) was 7.94 times as high as the AUC0-20 min (p.o.). There were significant differences between Tmax, AUC, K12, K21, alpha and T1/2 alpha (P < 0.05). The relative bioavailability of salbutamol aerosol was 57.23% compared with its oral solution.

CONCLUSION

The assay was sensitive, specific, accurate and precise. The absorption process of salbutamol aerosol in human was significantly different from that of the oral solution. It was demonstrated that AUC0-20 min reflected the lung availability of salbutamol inhaler.

[The comparison of genetic divergences and its relationships to heterosis revealed by SSR and RFLP markers in rice (Oryza sativa L.)]

Genetic divergences of 57 entries from 6 ecotypes of rice were surveyed by PCR analysis with 48 pairs of SSR and by Southern analysis by 50 RFLP probes. It was indicated that SSR markers detected polymorphism efficiently in comparison to RFLP markers, considering the allele numbers per locus and average gene diversity. Among all of 1,596 pairs, 1,452 pairs of genetic distances based on SSR data (GDSSR) were higher than the genetic distance based on RFLP data (GDRFLP) by average of 0.2492. The average GDSSR of entries within indica subspecies was 0.5483, but GDRFLP was only 0.2776. And the GDSSR and GDRFLP of entries with japonica subspecies were 0.577, 0.2405 respectively. The average GDSSR between varieties of interspecies was 0.8074, and the average GDRFLP was 0.7310. It is suggested that the GDSSR between varieties of introspecies or interspecies are higher than that of GDRFLP. The analysis of correlation between GDSSR and GDRFLP of any entry with other 56 entries indicated that the correlation coefficient for typical Indica or Japonica varieties were higher, but lower for Indica-like or Japonica-like materials. It was also found that the relationships between genetic distance based on these two kinds of markers and the yield of hybrid performance were not significant, but most of the correlation coefficient between heterosis and GDRFLP or GDSSR arrived at highly significant level.

[Clinicopathologic analysis of ovarian serous and mucinous borderline tumors]

OBJECTIVE

To understand the clinicopathological features of ovarian borderline tumors and evaluate the significance of various histological appearances.

METHODS

Forty-five patients with borderline tumors were analyzed retrospectively. The stage distribution was stage I, 34 patients, stage II, 4 patients and stage III, 7 patients.

RESULTS

Forty-five cases of borderline tumors accounted for 25.4% of ovarian epithelial malignant tumors. The ratio of serous borderline tumors (SBTs) to mucinous borderline tumors (MBTs) was approximately 1:1.3. Nine of eleven SBTs with exophytic growth presented peritoneal implants, of which two were invasive and seven noninvasive. Two SBTs and 1 MBT recurred after 5, 4, and 1 years respectively. Thirty-three cases were followed from 2 to 9 years. The 5-year survival rate was 100% (Kaplan-Meir method).

CONCLUSIONS

The prognosis of the SBTs is favorable. SBTs with exophytic growth are often associated with peritoneum implants.

Effects of lower body positive pressure on muscle sympathetic nerve activity response [correction of respopnse] to head-up tilt

The benefits of lower body positive pressure (LBPP) are generally accepted for clinical treatment in medical emergencies caused by massive bleeding to maintain the systemic blood pressure. They are also used by NASA post spaceflight for preventing orthostatic hypotension in the astronauts. However, controversy still exists concerning the mechanisms underlying LBPP benefits. The purpose of this study was to test the hypothesis that the baroreflex-mediated enhancement in sympathetic activity would be attenuated by LBPP during an orthostatic challenge in humans. Specifically, we studied 1) the sympathetic activity responses by the microneurographic technique, using direct intraneural measurement of muscle sympathetic nerve activity (MSNA); and 2) the contributions of preload and afterload to the chances in MSNA response during orthostasis on application of LBPP. To accomplish these issues, MSNA was recorded microneurographically along with noninvasive measurement of the cardiovascular variables in all the subjects during exposure to a 70 degrees HUT with 30-mm Hg LBPP.

Cloning, expression patterns, and chromosome localization of three human and two mouse homologues of GABA(A) receptor-associated protein

Type A receptors of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter, contain alpha, beta, delta, gamma, and rho subunits. The gamma subunit has four subtypes: gamma1, gamma2, gamma3, andgamma4. GABA(A) receptor-associated protein (GABARAP) was previously demonstrated to act as a linker protein between microtubules and the gamma2 subunit of GABA(A) receptors. However, no other linker proteins have been identified as mediating the linkage of microtubules and the remaining subunits of GABA(A) receptors. In this study we identified three human paralogues (GABARAPL1, GABARAPL2, and GABARAPL3) and two mouse orthologues (Gabarapl1 and Gabarapl2) of human GABARAP, all of which encoded 117 amino acids, as does Gabarapl. The expression patterns of GABARAPL1, GABARAPL2, and GABARAP in 16 adult tissues showed that they were expressed ubiquitously. The expression levels of GABARAPL1 as a 2.3-kb transcript were very high in brain, heart, peripheral blood leukocytes, liver, kidney, placenta, and skeletal muscle, very low in thymus and small intestine, and moderate in other tissues tested. The unique 1.35-kb transcript of GABARAPL2 was expressed at high levels in heart, brain, testis, prostate, ovary, spleen, and skeletal muscle, at very low levels in lung, thymus, and small intestine, and moderately in other tissues tested. For GABARAP, a 1.3-kb transcript was abundantly expressed in all tested tissues with small variation. The expression patterns of Gabarapl1 and Gabarapl2 were similar to those of their counterparts in human. In addition, GABARAPL1 was localized to human chromosome 12p12.3 and GABARAPL2 to 16q22.3-q24.1 by RH mapping, while GABARAP and GABARAPL3 were found to be localized at chromosomes 17p13.2 and 15q25.1, respectively, by searching the related databases. Sequence comparison of the cDNAs and their corresponding genomic sequences shows that GABARAP, GABARAPL1, and GABARAPL2 are composed of four exons each, while GABARAPL3 is distributed only at one exon.

Effect of diabetes and insulin treatment on nitric oxide synthase content in rat corpus cavernosum

AIM

To study the effect of diabetes mellitus and insulin treatment on rat penile nitric oxide synthase content.

METHODS

Male Wistar rats were divided at random into two groups: the Control (n = 8) and the Diabetic (n = 17). Diabetes mellitus was induced by intraperitoneal injection of streptozotocin. The diabetic animals were then randomly divided into two subgroups: diabetic rats without insulin treatment (n = 7) and diabetic rats with insulin treatment (n = 10). The neuronal nitric oxide synthase (nNOS) in the penile corpus cavernosum were assayed by immumohistochemical staining with specific antibody to nNOS and the nNOS-positive nerve fibers were counted semiquantitatively under a high power microscope.

RESULTS

The nNOS- positive nerve fibres in diabetic rats with treatment was higher than that in diabetic rats without treatment (P < 0.05) and lower than that in the controls (P < 0. 01). The nNOS-positive nerve fibres in diabetic rat without treatment were also lower than that in the controls (P < 0. 01).

CONCLUSION

In streptozotocin-induced diabetic rats, the nNOS content in the penile corpus cavernosum was significantly decreased. Insulin treatment at the dose level employed partially restores the penile nNOS content in these rats.

[Effects of laser welding on ceramic fused to metal]

OBJECTIVE

This study was aimed to investigate the bonding effect of laser welding on ceramic fused to metal.

METHODS

Ten laser welded CW-PA ceramo-alloy rods were fused with porcelain at fusion zone. The porcelain-metal bond strength was measured with pull-through test. SEM examination and EDAX analysis were performed. Ten non-welded CW-PA ceramo-alloy pull-rod plates were used as comparison.

RESULTS

The results showed that the bond strength of laser welded sample was 41.32 +/- 6.69 MPa, approaching to 45.71 +/- 9.98 MPa of the non-welded sample (P > 0.05). The microscope displayed the interface compacted union of the two phase boundary. There was no change in the elements and their ratio at the fusion zone.

CONCLUSION

These results indicate that laser welding does not affect ceramic fused to metal.

Molecularly imprinted polymers from nicotinamide and its positional isomers

Imprinted polymers were prepared for nicotinamide and its positional isomers. The influence of porogenic solvent and functional monomer on recognition properties of the polymer was compared. The results indicated that two functional groups, the heterocyclic nitrogen and the amide group, in the nicotinamide or isonicotinamide molecule have a synergistic effect in binding to the polymer. The polymers prepared with nicotinamide and isonicotinamide can be used as HPLC stationary phase for the separation of positional isomers of nicotinamide or isonicotinamide, while the polymer prepared with picolinamide showed no specificity toward the template. The mechanisms for the differences in recognition are discussed. In addition to the retention of polymers to their templates the polymers also displayed excellent retention to nicotinic acid and isonicotinic acid, compounds structurally similar to the template. This dual recognition property of the polymer may be useful in circumstances where the preparation of a polymer for a specific template may be problematic because of poor stability or solubility.

[Effects of clasp designs of Kennedy Class II RPD on the displacement of alveolar bone around the abutment tooth--an under load hologram study]

OBJECTIVE

This article is to investigate the effects of different clasp designs of Kennedy class II RPD on the displacement of alveolar bone around the abutment tooth.

METHODS

This experiment was carried out by using a separate human mandible. Five clasp designs were examined in this experiment, including RPA, RPI, modified RPI (mRPI), three-arm clasps and buccal wrought wired three-arm clasps. Hologramatic measurement was applied to record the different effects of these five designs of clasps on buccal and lingual alveolar bone.

RESULTS

The RPI clasp was found to cause the smallest bone displacement. Generally, the clasps with the mesial occlusal rest (RPA, RPI, mRPI) caused smaller bone displacements than those with distal occlusal rests. The bar clasps brought about evenly spread bony displacements, however, the circumferential clasp caused highly concentrated displacement around apical site of the abutment tooth.

CONCLUSION

The results suggest that mesial occlusal rests and bar clasps are preferable designs in this kind of prostheses.

Mie theory for light scattering by a spherical particle in an absorbing medium

Analytic equations are developed for the single-scattering properties of a spherical particle embedded in an absorbing medium, which include absorption, scattering, extinction efficiencies, the scattering phase function, and the asymmetry factor. We derive absorption and scattering efficiencies by using the near field at the surface of the particle, which avoids difficulty in obtaining the extinction based on the optical theorem when the far field is used. Computational results demonstrate that an absorbing medium significantly affects the scattering of light by a sphere.

Carbohydrate-directed conjugation of cobra venom factor to antibody by selective derivatization of the terminal galactose residues

Cobra venom factor (CVF) can cause cell death by complement-mediated bystander cell lysis. Several studies have investigated CVF for application in cancer therapy by conjugating CVF to antibodies against tumor cell surface-specific antigens via the side-chain amino acid residues. In most cases, the activity of CVF was markedly impaired, presumably by modification of the factor B binding domain due to random derivatization. Since CVF is a glycoprotein and its oligosaccharide chains are distal to the factor B binding domain, coupling of CVF to antibodies through its oligosaccharide chains is expected to yield immunoconjugates with retention of CVF activity and elimination of the immunoreactivity of the terminal alpha-galactosyl residues. In this study, we investigated the carbohydrate site-directed conjugation of CVF to a monoclonal IgG specific to a cell-surface antigen of human ovarian cancer cells. The terminal galactosyl residues of CVF were selectively modified at C-6 by treatment with galactose oxidase, and the generated aldehyde groups were derivatized in situ with hydrazides containing either protected thiol or maleimide functional groups. The CVF derivatives were allowed to react with thiol groups introduced to the antibody by derivatization with 2-iminothiolane to yield carbohydrate site-directed CVF-antibody conjugates. In both cases, 30-40% of the antibody cross-linked to CVF to yield predominantly monovalent CVF-antibody conjugates. The purified immunoconjugates retained 70-75% of CVF activity and significant level of antigen-binding capacity. This is the first study to exploit the oligosaccharide chains of CVF for the preparation of active immunoconjugates.

Mouse phosphoglycerate mutase M and B isozymes: cDNA cloning, enzyme activity assay and mapping

Two mouse cDNAs encoding the non-muscle-specific or brain isoform (type B, Pgam1) and the muscle-specific isoform (type M, Pgam2) of phosphoglycerate mutase (PGAM) were isolated and characterized. Pgam1 contains a 765 bp open reading frame (ORF) coding for a 254-residue protein while Pgam2 contains a 762 bp ORF coding for a 253-residue protein. The deduced proteins of mouse Pgam1 and Pgam2 are highly similar to those of human and rat (> or = 93% similarity). Northern blot analysis showed that the expression patterns of Pgam1 and Pgam2 were distinct. Pgam1 was expressed as a 2.1-kb transcript highly in brain and kidney and moderately in liver, thyroid, stomach and heart, whereas Pgam2 was expressed as a 1.0-kb transcript highly in muscle, testis and moderately in heart and lung, but was not detectable in the other six tissues examined. Transfecting the cDNA fragments containing the entire ORFs of these two cDNAs into COS7 cells for transient expression, respectively, the enzyme activities of mouse Pgam1 and Pgam2 were detected to be 2.2-2.5 times of those of COS7 cells and COS7 cells transfected with vector, proving the validity of mouse Pgam1 and Pgam2 cDNAs we report here. Pgam1 and Pgam2 were assigned to 116.16 cR from D19Mit52 and 29.57 cR from D11Mit129, respectively, by radiation hybrid method. The partial genomic sequence of Pgam2 was determined, which showed that mouse Pgam2 consisted at least three exons and two introns. In addition, a pseudogene of Pgam1, Pgam1-ps1, was identified from mouse genomic sequence.

1,2,5-Thiadiazolidin-3-one 1,1 Dioxide: A Powerful Scaffold for Probing the S′ Subsites of (Chymo)trypsin-Like Serine Proteases

The 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold (I) embodies a motif that allows it to dock to the active site of (chymo)trypsin-like proteases in a predictable and substrate-like fashion. Consequently, inhibitors derived from this heterocyclic scaffold interact with both the S and S' subsites of an enzyme. Exploitation of binding interactions with both the S and S' subsites of a target enzyme may lead to compounds with greatly enhanced enzyme selectivity and inhibitory potency. This preliminary report describes the use of a series of compounds having the heterocyclic scaffold linked to various amino acids to probe the S' subsites of human leukocyte elastase (HLE), proteinase 3 (PR 3), and cathepsin G (Cat G). For comparative purposes, a series of compounds derived from a related scaffold, isothiazolidin-3-one 1,1 dioxide (II), was also generated. Several of the compounds were found to be highly potent and selective time-dependent inhibitors of HLE, PR 3, and Cat G.

Cloning and characterization of human VPS35 and mouse Vps35 and mapping of VPS35 to human chromosome 16q13-q21

Maintenance of different organelles in eukaryotic cells depends on sorting proteins, which ensure the proper delivery of organelle-specific proteins. The studies on yeast (Saccharomyces cerevisiae) VPS35, a hydrophilic membrane protein having a direct role in the retrieval of cargo proteins, suggest a mechanism underlying a possible lysosomal protein-sorting pathway in mammalian cells. Here, we report the isolation of human and mouse VPS35 cDNAs, which are 3208 and 3186 bp in length, respectively. The deduced proteins of the two cDNAs, which are both composed of 796 amino acids and share 99% identity, show homology to yeast VPS35 and other VPS35 homologues of various sources ranging from Schizosaccharomyces pombe to Drosophila melanogaster (31-56% identity and 49-71% similarity), especially in their amino- and carboxyl-termini. The conservation of VPS35 suggests that the function of this class of protein is important. The results of Northern hybridization of human VPS35 in 16 tissues showed that one transcript of 3.6 kb was highly expressed in brain, heart, testis, ovary, small intestine, spleen, skeletal muscle, and placenta and expressed at moderate or low levels in other tissues. Another transcript of 3.0 kb was also expressed with proportionally lower levels than the 3.6-kb transcript in all the tissues except that the 3.0-kb transcript was not detected in brain. Mouse Vps35 was widely expressed as a 3.4-kb transcript. In addition, human VPS35 was assigned to human chromosome 16q13-q21 by radiation hybrid mapping.

Leg venous compliance in orthostatic intolerance before and after 14-day head-down bed rest

To test the hypothesis that increased leg venous compliance (LVC) is one of the contributory factors to orthostatic intolerance (OI) after simulated microgravity, 28 healthy young males were exposed to a 14-day head-down bed rest, and LVC was measured by venous occlusion plethysmography. Orthostatic tolerance was evaluated by a 60 degree head-up tilt (HUT) for 15 min. Sixteen subjects suffered from OI after the bed rest. They were then divided into orthostatic tolerance (non-fainters, n=12) and intolerance (fainters, n=16) groups. We found that fainters had significantly larger LVC before bed rest (0.055 +/- 0.003 vs. 0.065 +/- 0.002 ml 100 ml-1 mm Hg-1, non-fainter vs. fainter; P < 0.05). After bed rest, LVC markedly increased in both groups. In all the subjects calf circumference was reduced on average by 4.7% and the percent change in LVC was negatively correlated with the percent change in calf circumference when all subjects' data were combined after bed rest (r = -0.42, P < 0.05). Our results did not support the hypothesis that increased LVC is the contributory factor to OI after a 14-day bed rest; however, the mechanisms behind the large LVC in the fainters before bed rest are unclear, and the initial LVC might be a predictive indicator for OI after microgravity exposure.

A clinical comparative study on effects of intracavernous injection of sodium nitroprusside and papaverine/phentolamine in erectile dysfunction patients

AIM

To study the effect of intracavernous sodium nitroprusside (SNP), a nitric oxide (NO) donor, on penile erection.

METHODS

Forty-two patients with erectile dysfunction (ED) were randomly assigned to receive SNP 300 micrograms or the control drugs (papaverine 30 mg + phentolamine 1 mg) intracavernously crosswise one week apart. The penile length, circumference and hardness after the administration of the experimental and control drugs were assessed and compared statistically.

RESULTS

(1) There was no significant difference between the changes in penile length and circumference in the two occasions; (2) In 25 SNP and 28 control cases, the hardness of the penis was scored above 100 as evaluated by the Virag method (P > 0.05); (3) The duration of erection in the controls was longer than that in the SNP, but there were three priapism in the controls and not a single one in the SNP; (4) there was no apparent change in the heart rate and blood pressure in both occasions; other side effects were minimal except slight local pain in a few controls.

CONCLUSION

SNP facilitates relaxation of the penile smooth muscle and penile erection without significant side effects. SNP may be used in ED patients that experience pain and priapism with papaverine/phentolamine.

Effect of aging on muscle sympathetic nerve activity and peripheral venous pressure in humans

To elucidate the effect of aging on blood pressure regulation, especially cardiopulmonary baroreflex in humans, we measured the resting value of muscle sympathetic nerve activity (MSNA), heart rate (HR), blood pressure (BP), peripheral venous pressure (PVP), and calf blood flow (CBF) in eight healthy young male subjects and eight healthy aged subjects, and compared the responses to the low level of lower body negative pressure (LBNP) between the two groups. The resting MSNA was higher, and the response of MSNA to LBNP was lower in the aged group than in the young group; the response of PVP to LBNP was also lower in the aged than in the young group. Delta MSNA/delta PVP showed no significant differences between the two groups. The present findings indicate that the effect of LBNP on cardiopulmonary baroreflex is greater in young people than in aged people, but that cardiopulmonary baroreflex may be preserved with advancing age.

Muscle sympathetic nerve activity (MSNA) during high-intensity, isometric leg exercise in humans

Muscle sympathetic nerve activity (MSNA) is activated during mild-intensity isometric handgrip exercise, but not during isometric leg exercise at a similarly relative intensity. It is unclear whether MSNA is increased by leg exercise at heavy intensity in humans. We aimed to examine how MSNA responds to high-intensity, isometric leg exercise in humans. Eight young healthy male volunteers performed isometric plantar flexions of high intensity (70% of MVC) for 2 min, followed by 2 min of post-exercise muscle ischemia (PEMI; isolated muscle metaboreflex stimulation), with monitoring of muscle sympathetic nerve activity (MSNA), heart rate and arterial blood pressure. MSNA was increased at the onset of exercise (p<0.05), and further increased to 512 +/- 111% of baseline at the second min of exercise (p<0.05). Furthermore, MSNA remained elevated above baseline during PEMI (259 +/- 41 % of baseline, p<0.05). Heart rate also rose at the onset of the test (P<0.05) and gradually increased all through the test (p<0.05), but decreased to baseline level during PEMI. Mean blood pressure was progressively increased from the onset to the end of test (p<0.05), and remained elevated above baseline during PEMI (p<0.05). In summary, MSNA was increased progressively throughout high-intensity, isometric plantar flexion in humans, primarily due to muscle metaboreflex.

Finite-difference time-domain solution of light scattering by dielectric particles with large complex refractive indices

The finite-difference time-domain (FDTD) technique is examined for its suitability for studying light scattering by highly refractive dielectric particles. It is found that, for particles with large complex refractive indices, the FDTD solution of light scattering is sensitive to the numerical treatments associated with the particle boundaries. Herein, appropriate treatments of the particle boundaries and related electric fields in the frequency domain are introduced and examined to improve the accuracy of the FDTD solutions. As a result, it is shown that, for a large complex refractive index of 7.1499 + 2.914i for particles with size parameters smaller than 6, the errors in extinction and absorption efficiencies from the FDTD method are generally less than approximately 4%. The errors in the scattering phase function are less than approximately 5%. We conclude that the present FDTD scheme with appropriate boundary treatments can provide a reliable solution for light scattering by nonspherical particles with large complex refractive indices.

Skin sympathetic neuroeffector response is attenuated dose-dependently by systemic prostaglandin E1 injection in humans

To clarify the effects of prostaglandin E1 (PGE1) on the vasoconstrictive responses, we compared the correlation between the amplitude of integrated skin sympathetic nerve activity (SSNA) and per cent reduction in skin blood flow (SBF) before and after the infusion of lipo PGE1 and placebo (bolus one-shot infusion, single blind study), and constant rate infusion of PGE1 (10 and 50 ng kg(-1) min(-1) by infusion pump, dose-dependency study) in ten healthy men. SSNA was recorded microneurographically from the median nerve simultaneously with SBF by laser Doppler flowmetry at the index fingertip. The measurement was conducted 30 min after injection of lipo PGE1 or placebo, and during the drip infusion of 10 and 50 ng kg(-1) min(-1) of PGE1 with maneuvers to enhance SSNA. The resting and activated skin blood flow were not significantly different between 10 ng lipo PGE1 and placebo administration, and between baseline and 10, 50 ng kg(-1) min(-1) of PGE1 injection. The vascular response, defined as the slope of regression line between logarithm of amplitude of integrated SSNA bursts and the reduction in SBF, was significantly suppressed by injection of lipo PGE1 as compared with that by placebo. It was also decreased dose-dependently by the constant rate infusion of PGE1 (10 and 50 ng kg(-1) min(-1)). We concluded that the intravenous injection of PGE1 attenuates vasoconstrictive responses to SSNA, and analysis of the relations between SSNA and vasoconstrictive response, i.e. the neuroeffector response, is suggested to be an important tool to assess the drug effect.

Representation of accuracy in the dorsal premotor cortex

The endpoint accuracy of a reaching movement strongly affects kinematics, particularly during the final phases of movement. However, where and how accuracy is represented in the central nervous system remains unknown. In this study, the discharge of 150 neurons located primarily in the dorsal premotor cortex (PMd), were recorded from monkeys performing an instructed delay, centre-out reaching task in which movement direction and target size were systematically varied. Linear regression analyses were used to assess the dependence of movement kinematics and cell discharge on target direction, size and tangential velocity (i.e. speed). The speed and timing of the movement were dependent on both direction and target size. Initially direction was the dominant predictor whilst target size became more important as the hand reached the target. A temporal multiple linear regression analysis found significant correlations with target size in 99 of 150 cells. The discharge of 134 cells was directionally tuned and 83 cells modulated with mean speed. Significant correlations of discharge with target size occurred throughout the task as did correlations with direction. However, correlations with direction preferentially occurred early in the task, prior to movement onset, whilst correlations with target size tended to occur late, well after movement onset. This temporal dependency of the firing in relationship to target direction and size mirrored that observed for the kinematics. We conclude that the discharge of PMd cells is highly correlated with the accuracy requirement of the movement. The timing of the correlations suggest that accuracy information is available for the planning and for the on-line control of endpoint accuracy.

Light Scattering from Deformed Droplets and Droplets with Inclusions. II. Theoretical Treatment

We provide theoretical results from the scattering of light by deformed liquid droplets and droplets with inclusions. With improved instrumentation and computer technologies available, researchers are able to employ two-dimensional angular optical scattering as a tool for analyzing such particle systems and which then could be applied in industrial, occupational, and military aerosol measurement. We present numerically calculated spatial light-scattering data from various droplet morphologies. We describe characteristic features of the theoretical data and compare these with the experimental results.

[Cloning and tissue expression pattern analysis of the human citrate synthase cDNA]

Tricarboxylic acid (TCA) cycle is an important way to generate ATP, which is widely distributed in the cells of animal, plant or microorganism. It catalyses the catabolism of sugar as well as protein and fat. Citrate synthase plays a key role in regulating TCA cycle and is responsible for catalysing the synthesis of citrate from oxaloacetate and acetyl CoA. Screening of genomic informatics was performed by using pig citrate synthase cDNA as a probe and a contig which is 1636 bp long and has highly homologous to the pig citrate synthase cDNA was obtained from selected ESTs with the ASSEMBLY program. According to the sequence of this contig, a pair of primers was designed and used to amplify cDNA libraries. A 1492 bp cDNA containing an open reading frame encoding 466 amino acids was cloned from human testis and skeletal muscle cDNA libraries. The deduced amino acid sequence of the cDNA showed 95%, 92% and 60.9% identity to pig, chicken and yeast citrate synthase respectively. Because the deduced amino acids sequence contains a highly conserved motif of citrate synthase from three different species, it is believed that this cDNA may be a transcript of human citrate synthase gene. Northern analysis showed that the human citrate synthase was expressed at high level in heart and muscle, at middle level in brain, kidney and pancreas tissues, not detectable in thymus and small intestine tissues, and at low level in other nine tested human tissues.

Head-down bed rest alters sympathetic and cardiovascular responses to mental stress

Astronauts usually work under much mental stress. However, it is unclear how and whether or not an exposure to microgravity affects physiological response to mental stress in humans. To examine effects of microgravity on vasomotor sympathetic and peripheral vasodilator responses to mental stress, we performed 10 min of mental arithmetic (MA) before and after 14 days of 6 degrees head-down bed rest (HDBR), a ground-based simulation of spaceflight. Total muscle sympathetic nerve activity (MSNA, measured by microneurography) slightly increased during MA before HDBR, and this increase was augmented after HDBR. Calf blood flow (measured by venous occlusion plethysmography) increased and calf vascular resistance (calculated by dividing mean blood pressure by calf blood flow) decreased during MA before HDBR, but these responses were abolished after HDBR. Increases in heart rate and mean blood pressure during MA were not different between before and after HDBR. These findings suggest that HDBR augmented vasomotor sympathoexcitation but attenuated vasodilatation in the calf muscle in response to mental stress.

Cloning and characterization of human DDX24 and mouse Ddx24, two novel putative DEAD-Box proteins, and mapping DDX24 to human chromosome 14q32

DEAD-box proteins are a large group of putative RNA helicases that exist ubiquitously in organisms ranging from bacteria to humans. They are likely to play important roles in many different RNA metabolic processes. In this paper, we report the cloning of human DDX24, a putative DEAD-box protein, and its ortholog, Ddx24 in mouse. The deduced proteins encoded by these two cDNAs share 78.7% identity at the amino acid level and possess all the well-conserved motifs of DEAD-box proteins. However, little homology can be found between them and other DEAD-box proteins, even in their core region (identity <40%). Northern blot analysis showed that a 3.0-kb transcript of human DDX24 exists ubiquitously in the 16 human tissues examined and was most abundant in heart and brain, but with lowest levels in thymus and small intestine. The mouse Ddx24, whose transcript is 4.0 kb, was also expressed widely in 10 tissues tested with the highest level in heart and testis. By radiation hybrid mapping, the human DDX24 gene was localized to human chromosome 14q32 between the markers D14S81 and D14S265. Moreover, the gene structure of DDX24 was determined by comparing its cDNA and genomic sequence from BAC R-1089B7, which showed that the gene spanned a 30-kb region and consisted of at least nine exons.

Body temperature and skin blood flow during a 14-day bed-rest in a head-down tilt position in humans

Exposure to microgravity or simulated microgravity is known to affect regulatory function in autonomic nervous system. With regard to thermoregulation, simulated microgravity impairs sweating and induces lower skin and higher internal temperatures during physical work. During supine rest after HDT bed rest, the internal temperatures were reported to be higher than those of pre-HDT bed rest in some studies but not in others. There is no report about the dynamic changes of skin blood flow during 14-day HDT bed rest. The process of HDT bed-rest deconditioning on the function of the thermoregulatory system is virtually unknown. The HDT induces an immediate cephalad fluid shift which would inhibit the sympathetic outflow through the arterial and cardiopulmonary baroreflexes, which may increase the skin blood flow. On the other hand, prolonged HDT bed rest induces dehydration, which will increase sympathetic outflow through cardiopulmonary baroreceptor modulation. Both sympathetic activation and dehydration itself will decrease skin blood flow. It seems probable that the general effect on skin blood flow may reverse along the HDT bed rest. However, the dynamic characters of skin blood flow and body temperature during the HDT bed rest have not been studied thoroughly. Therefore, the purpose of present study was to investigate the changes of skin blood flow and body temperature during 14 days HDT bed rest.

Molecular cloning and mapping of the brain-abundant B1gamma subunit of protein phosphatase 2A, PPP2R2C, to human chromosome 4p16

Protein phosphatase 2A (PP2A) is one kind of serine/ threonine protein phosphatase regulating mainly cell growth and division. It comprises three subunits, A, B, and C. The B-subunit is involved in enzyme activity and substrate specificity. The B-subunit family is of great diversity and is divided into three classes, the B1, B2, and B3 subfamilies. Until now, two members of the B1 subfamily, B1alpha and B1beta, have been identified in human. In this report, the third member of the sub-family, B1gamma, was identified, and its cDNA was isolated from a human brain cDNA library. This novel cDNA is 4,120 bp in length and contains an open reading frame (nt 55-1,398) encoding 447 amino acid residues. The putative protein shares 81 and 85% identity with B1alpha (PPP2R2A) and B1beta (PPP2R2B), respectively, and was named PPP2R2C for its high level of homology to the other two isoforms. One remarkable characteristic of this novel gene is that it is highly expressed in brain with a 4.7-kb transcript while it is nearly undetectable in other tissues. In addition, the PPP2R2C gene was localized to human chromosome 4p16 between markers D4S2925 and D4S3007 with 5.45 cR (LOD > 14) and 2.63 cR (LOD > 15) RH distance, respectively, by radiation hybrid panel mapping.

Effects of leg venous hemodynamics on cardiovascular responses to lower body negative pressure and aging

In aged people, decreases in stroke volume and cardiac output during orthostatic challenge are less. It is suggested that the stiffness of blood vessels is greater in the elderly, blunting leg venous pooling and drop in central blood volume in an upright position. Leg venous hemodynamics plays an important role in human cardiovascular homeostasis against gravitational stress. This study aimed to clarify how aging influences the leg venous hemodynamics and its contribution to cardiovascular homeostasis during lower body negative pressure (LBNP) in humans.

Responses of muscle sympathetic nerve activity to static handgrip exercise after 14 days of exposure to simulated microgravity

Decrease in muscle perfusion affects on cardiovascular response to exercise. Muscle hypoperfusion enhances the increase in blood pressure responses to exercise. Muscle perfusion depends not only on central blood pressure but also how fit the active muscle is above or below the heart level; muscle perfusion decreases as arm is elevated. Static exercise increases muscle sympathetic nerve activity (MSNA) innervating vessels in non-active muscles. The exercise-induced increase in MSNA is mainly mediated by stimulating chemosensitive muscle afferents in active muscles. However, the effect of arm elevation on MSNA during forearm exercise is not examined. On the other hand, space flight and simulated microgravity exposure causes reduction in muscle blood flow, suggesting chronic muscle hypoperfused condition during simulated microgravity. Therefore, there is a possibility that arm elevation after microgravity exposure alters MSNA responsiveness during exercise. However, arm elevation effect after exposure to simulated microgravity is not examined.

Arterial baroreflex control of sympathetic vasoconstrictor traffic and orthostatic intolerance after head-down bed rest

The purpose of the present study is to examine the changes in the arterial baroreflex control of muscle sympathetic nerve activity (MSNA) after head-down bed rest (HDBR), in relation to orthostatic hypotension after HDBR. Therefore, we performed 60 degrees head-up tilt (HUT) tests before and after 14 days of HDBR, with monitoring MSNA, heart rate and blood pressure. We calculated the gain of the arterial baroreflex control of MSNA, and compared the gains between the subjects who did (defined as the fainters) and those who did not (defined as the nonfainters) become presyncopal in HUT tests after HDBR.

Nonlinear pharmacokinetics of paclitaxel in ovarian cancer patients

AIM

To characterize the disposition of paclitaxel in patients with ovarian carcinoma after a 3-h infusion.

METHODS

Fifteen patients with advanced ovarian cancer were enrolled and were administered paclitaxel in a 3-h infusion at dosing levels of 135 mg/m2, 175 mg/m2, and 235 mg/m2. Thirteen plasma samples were obtained during the infusion and up to 24 h after the infusion. Paclitaxel concentrations in plasma were determined by HPLC assay. Pharmacokinetic parameters were assessed with noncompartment model and model-dependent method.

RESULTS

The disposition of paclitaxel in patients with ovarian cancer conformed to a two-compartment model. The main pharmacokinetic parameters of three groups were T1/2 beta (5.18 +/- 3.49), (6.26 +/- 2.21), and (6.99 +/- 1.45) h, AUC (14.71 +/- 0.76), (39.09 +/- 13.10), and (66.52 +/- 12.23) mg.h.L-1, Cl (14.29 +/- 0.74), (7.52 +/- 2.15), and (6.25 +/- 1.93) L.h-1, respectively.

CONCLUSION

The disposition of paclitaxel was nonlinear after a 3-h infusion. There was individual variability of metabolism among patients.

Regulation of the venous capacitance during microgravity

The purpose of this paper is to report our recent investigations on the relationship between sympathetic tone and leg venous compliance, as well as on the baroreflex control of leg venous compliance after simulated microgravity exposure in healthy humans.

Molecular cloning, expression characterization, and mapping of a novel putative inhibitor of rho GTPase activity, RTKN, to D2S145-D2S286

The Rho proteins are a class of small molecular GTPases that regulate multiple fundamental cellular processes by mediating the G-protein-coupled receptor signaling pathway. Rhotekin, which is one of the downstream target molecules of Rho with a Rho binding motif class I domain, can inhibit endogenous or RhoGAP-stimulating Rho GTPase activity to regulate the signaling pathway. Here, a novel human cDNA containing an intact open reading frame that encodes 544 amino acids has been identified. As this putative protein shares 84. 6% amino acid identity with mouse Rhotekin, and has a tandem Rho binding domain class 1 and Pleckstrin homology domain, it was regarded as a human homologue of the mouse Rhotekin and assigned a symbol of RTKN. With the human Rhotekin cDNA as a probe, Northern hybridization revealed that a 4.0-kb transcript was expressed at a high level in prostate and at a middle level in 13 of 16 tissues examined, but it cannot be detected in liver and lung tissues. Meanwhile, a 2.4-kb transcript was expressed at a middle level in prostate and another 3.0-kb transcript in kidney. In addition, the RTKN gene was localized to chromosome 2p13 between markers D2S145 at 6.94 cR (LOD > 12) and D2S286 at 8.12 cR (LOD > 9.7) by radiation hybrid panel mapping. Compared with BAC clone AC005041 sequence, there were 12 exons for the RTKN gene and it spanned a 16.5-kb genomic region.

[Cloning and tissue expressive pattern analysis of the human ribosomal S6 kinase-RPS6KA5 cDNA]

Human ribosomal protein S6 kinase includes two protein families: P90RSK and P70S6K, they participate in two different signaling pathways. When the two kinases were inhibited by their antibodies or rapamycin, the proliferation of cells was arrested. However, their analog, the immunosupressant FK-506, can inhibit the proliferation of fibroblast PBL1 without interfering with the activities of P90RSK, P70S6K and MAPK. We take the tactics of "homolog screening" to demonstrate whether there are some novel proteins which can substitute for the known P90RSK and P70S6K or other pathways without interfering with the known P90RSK and P70S6K. With the conserved sequence of mouse p90RSK as a probe, we screened the homologous sequence in NCBI EST database and got three human EST fragments. With the assembled contig as a probe to screen human brain cDNA library, a full-length cDNA of 3833 bp was attained. It contains a completed open reading frame from 165 bp to 2570 bp encoding 802 amino acids. The putative protein has higher homology with other members of p90RSK family. The gene was named RPS6KA5, the accession number in GenBank is AF090421. Northern hybridization showed the gene expressed in 16 human tissues tested, and the gene was localized in 14q31-32.1 by RH mapping. Another novel P70S6K gene has also been cloned. Thus, our initial presumption that there is an analog of known P90RSK and P70S6K in human beings was proved.

A comparison of autonomic responses in humans induced by two simulation models of weightlessness: lower body positive pressure and 6 degrees head-down tilt

Six-degree head-down tilt (HDT) is well accepted as an effective weightlessness model in humans. However, some researchers utilized lower body positive pressure (LBPP) to simulate the cardiovascular and renal effects of a decreased gravitational stress. In order to determine whether LBPP was a suitable model for simulated weightlessness, we compared the differences between these two methods. Ten healthy males, aged 21-41 years, were subjected to graded LBPP at 10, 20 and 30 mmHg, as well as 6 degrees HDT. Muscle sympathetic nerve activity (MSNA) was microneurographically recorded from the tibial nerve along with cardiovascular variables. We found that MSNA decreased by 27% to a similar extent both at low levels of LBPP (10 and 20 mmHg) and HDT. However, at a high level of LBPP (30 mmHg), MSNA tended to increase. Mean arterial pressure was elevated significantly by 11% (10 mmHg) at 30 mmHg LBPP, but remained unchanged at low levels of LBPP and HDT. Heart rate did not change during the entire LBPP and HDT procedures. Total peripheral resistance markedly increased by 36% at 30 mmHg LBPP, but decreased by 9% at HDT. Both stroke volume and cardiac output tended to decrease at 30 mmHg LBPP, but increased at HDT. These results suggest that although both LBPP and HDT induce fluid shifts from the lower body toward the thoracic compartment, autonomic responses are different, especially at LBPP greater than 20 mmHg. We note that high levels of LBPP (>20 mmHg) activate not only cardiopulmonary and arterial baroreflexes, but also intramuscular mechanoreflexes, while 6 degrees HDT only activates cardiopulmonary baroreflexes. We conclude that LBPP is not a suitable model for simulated weightlessness in humans.

[Stress-corrosion test of laser welded ceramic alloys]

OBJECTIVE

The corrosion properties of dental material are very critical. This study is to investigate the corrosion properties of laser welded basemetalalloys.

METHODS

The precise stainless rod molds had been made in size of phi 3 mm x 4 mm, with which 20 wax patterns were made. They were invested with inner investment (Bellavest) and outer investment (phosphate and gypsum). Then they were casted with CW-PA (Ni-Cr-Nb) alloys. All casted alloy rods were ultra-sonic washed in distilled water. Every two rods were contacted longitudinally by a special welding jig. Laser welding machine (DL-2002) was used to weld them at 305 V, 20 ms. The specimens were divided into 2 groups as following: 1. The group of stress-corrosion: 5 laser welded samples were subjected to the stress-corrosion test under 261.44 MPa in the 37 degrees C artificial saliva for 3 months in a special stress-corrosion test jig. After that, the ultimate tensile strength (UTS) was tested, the surface microcrack at the fusion zone (FZ), the heat affecting zone (HAZ) and the interface zone was observed with SEM (ARMY-1845, USA), the elements were also analyzed with EPMA (ARMY-1845, USA) at the fusion zone (FZ), the parent metal zone and the interface zone. 2. The other 5 laser welded samples were made as the controlled group. No special treatment were done to them, and the UTS was also tested, the surface of the micro crack and the elements at the FZ, the HAZ, parent metal zone and the interface zone were observed and analyzed with SEM, EPMA as well.

RESULTS

The study showed us that the UTS of the stress-corrosion group was 502.48 +/- 12.49 MPa, while that of the controlled group was 446.05 +/- 82.50 MPa, there was no significant difference (P > 0.05). There was no microcrack on any sample's surface at the FZ, the HAZ and the interface zone. The main elements of the FZ were Ni(56.63%), Cr(19.36%), Nb (6.57%), Si(6.01%), Al(0.32%) and Mo(11.11%), while the elements of the parent metal zone were Ni(60.77%), Cr (20.59%), Nb(5.03%), Si(3.95%), Al(0.37%) and Mo(9.29%) respectively.

CONCLUSION

The results suggest that the corrosion properties of laser welded alloys are excellent.

[Generation of cytotoxic T lymphocytes induced with HSP-PC70 derived from tumor cells]

OBJECTIVE

To investigate the killing effect of cytotoxic T lymphocytes (CTLs) induced with heat shock protein-peptide complexes (HSP-PC70) derived from tumor cells.

METHODS

Cell culture, flow cytometric analysis, affinity chromatography for protein extraction and purification, SDS-PAGE, Western blotting, CTL induction and expansion, and LDH release were used.

RESULTS

63.5% of the HcaF cells expressed HSP-PC70 on their membrane by FCM analysis under physiological condition, and the expression was 75.5% of the stressed cells (P < 0.01). HcaF cells had high HSP70 expression and inducibility. The cytotoxic activity of the CTLs induced with HSP70 obtained by affinity chromatography from HcaF cells was 84.2%, 47.9% and 14.8% respectively at E/T ratio of 50 : 1, 25 : 1 and 12.5 : 1. The CTLs were CD8 positive T cells. All mice which received CTL injection got long period survival (over 90 days, P < 0.01), compared with control group (10.6 days).

CONCLUSION

HSP-PC70 derived from tumor cells has strong immunogeneicity, and can activate CTLs with high peculiarity and killing activity. HSP-PC70 induced CTL adoptive immunotherapy can be a promising treatment for human to fight cancers.

Increased vasomotor sympathetic nerve activity and decreased plasma nitric oxide release after head-down bed rest in humans: disappearance of correlation between vasoconstrictor and vasodilator

We hypothesized that the relationship between resting levels of sympathetic vasoconstrictor nerve traffic and dilator substance nitric oxide (NO) release is altered after exposure to microgravity, resulting in abnormal peripheral resistance. To examine the hypothesis, we assessed muscle sympathetic nerve activity (MSNA) (microneurography), an indicator of NO release (plasma nitrite/nitrate concentrations) and leg vascular resistance (venous occlusion plethysmography) in 20 healthy male volunteers before and after 14 days of 6 degrees head-down bed rest (HDBR), the ground-based analogue of microgravity. MSNA increased, while plasma nitrite/nitrate concentrations decreased after HDBR. A significant positive correlation observed between MSNA and plasma nitrite/nitrate concentrations before HDBR disappeared after HDBR. Leg vascular resistance increased after HDBR. In conclusion, an imbalance between sympathetic vasoconstrictor traffic and NO release might contribute to elevated peripheral vascular resistance following HDBR.

Unique biochemical, cytotoxic, and antitumor activity of camptothecin and 4beta-amino-4'-O-demethylepipodophyllotoxin conjugates

Two compounds having a camptothecin (CPT) analog conjugated to the 4beta-amino-4'-O-demethylepipodophyllotoxin analog were evaluated for their biochemical and biological activities. W1[camptothecin-(para)-4beta-amino-4'-O-demethylepipodophyllotoxin] had no activity against topoisomerase II (TOP II), but inhibited topoisomerase I (TOP I) with an IC(50) value 2-fold higher than CPT. W2 [camptothecin-(ortho)-4beta-amino-4'-O-demethylepipodophyllotoxin] had inhibitory activity against TOP I and TOP II with IC(50) values 1.5-fold higher than either CPT or etoposide (VP-16). Both conjugates had similar cytotoxicity against the KB cell line, although the protein-linked DNA breaks (PLDBs) generated by W2 in KB cells were about 4-fold more than those of W1. No cross-resistance with the two conjugates was seen in a VP-16-resistant KB subline, which showed down-regulation of TOP II and overexpression of the multiple drug resistance-associated protein, or in a vincristine-resistant KB subline with overexpression of gp-170/mdr-1. The CPT-resistant KB variant (KB CPT 100), which has a reduction in TOP I content and another mechanism that occurs post-PLDB formation, was partially resistant to both compounds. W1 was not affected by this post-PLDB resistance mechanism. Cell cycle analysis demonstrated that W1 and W1 had similar cell cycle effects on KB and KB CPT 100 cells, which accumulated in S-phase upon drug treatment. These results suggested that W1 and W2 exerted their cytotoxicity through TOP I. In CPT-resistant cells, however, an unidentified target also may be involved in the cytotoxic action of W1 and TOP II may still be a target for W1. In vivo, W1 was more effective against the growth of human prostate cancer cells in nude mice than VP-16, CPT, or W2. Given its antitumor activity and unique biochemical mechanism of action, W1 warrants exploration as an antitumor compound.