Genetic influences on the difference in variability of height, weight and body mass index between Caucasian and East Asian adolescent twins.

OBJECTIVE: Twin studies are useful for investigating the causes of trait variation between as well as within a population. The goals of the present study were two-fold: First, we aimed to compare the total phenotypic, genetic and environmental variances of height, weight and BMI between Caucasians and East Asians using twins. Secondly, we intended to estimate the extent to which genetic and environmental factors contribute to differences in variability of height, weight and BMI between Caucasians and East Asians. DESIGN: Height and weight data from 3735 Caucasian and 1584 East Asian twin pairs (age: 13-15 years) from Australia, China, Finland, Japan, the Netherlands, South Korea, Taiwan and the United States were used for analyses. Maximum likelihood twin correlations and variance components model-fitting analyses were conducted to fulfill the goals of the present study. RESULTS: The absolute genetic variances for height, weight and BMI were consistently greater in Caucasians than in East Asians with corresponding differences in total variances for all three body measures. In all 80 to 100% of the differences in total variances of height, weight and BMI between the two population groups were associated with genetic differences. CONCLUSION: Height, weight and BMI were more variable in Caucasian than in East Asian adolescents. Genetic variances for these three body measures were also larger in Caucasians than in East Asians. Variance components model-fitting analyses indicated that genetic factors contributed to the difference in variability of height, weight and BMI between the two population groups. Association studies for these body measures should take account of our findings of differences in genetic variances between the two population groups.

A femtosecond laser pacemaker for heart muscle cells.

The intracellular effects of focused near-infrared femtosecond laser irradiation are shown to cause contraction in cultured neonatal rat cardiomyocytes. By periodic exposure to femtosecond laser pulse-trains, periodic contraction cycles in cardiomyocytes could be triggered, depleted, and synchronized with the laser periodicity. This was observed in isolated cells, and in small groups of cardiomyocytes with the laser acting as pacemaker for the entire group. A window for this effect was found to occur between 15 and 30 mW average power for an 80 fs, 82 MHz pulse train of 780 nm, using 8 ms exposures applied periodically at 1 to 2 Hz. At power levels below this power window, laser-induced cardiomyocyte contraction was not observed, while above this power window, cells typically responded by a high calcium elevation and contracted without subsequent relaxation. This laser-cell interaction allows the laser irradiation to act as a pacemaker, and can be used to trigger contraction in dormant cells as well as synchronize or destabilize contraction in spontaneously contracting cardiomyocytes. By increasing laser power above the window available for laser-cell synchronization, we also demonstrate the use of cardiomyocytes as optically-triggered actuators. To our knowledge, this is the first demonstration of remote optical control of cardiomyocytes without requiring exogenous photosensitive compounds.

Chromosomal assignment of LASP1 and LASP2 genes and organization of the LASP2 gene in chicken.

Lasp-1 and lasp-2 are actin-binding proteins that contain a LIM domain, two nebulin repeats and an SH3 domain with significant identity. We determined the chromosomal locations of the LASP1 and LASP2 genes in chicken by fluorescence in situ hybridization. The LASP1 gene was localized to a pair of microchromosomes and the LASP2 gene was localized to chromosome 2p3.1, indicating that the chromosomal locations of the LASP1 and LASP2 genes are highly conserved between chicken and human. The comparison of genomic and cDNA sequences of chicken lasp-2 and nebulette, a nebulin-related protein in muscle, suggested that both the corresponding mRNAs shared exons in the same manner as their human homologues. When compared with the domain structure of nebulette, another nebulin repeat was predicted for lasp-2, and all the nebulin repeats of lasp-2 were better conserved than those in nebulette. We also found the exon boundaries in nebulin repeats of lasp-2 were similar to those of other nebulin-related proteins.

Fluid shear stress activates Ca(2+) influx into human endothelial cells via P2X4 purinoceptors.

Ca(2+) signaling plays an important role in endothelial cell (EC) responses to shear stress generated by blood flow. Our previous studies demonstrated that bovine fetal aortic ECs showed a shear stress-dependent Ca(2+) influx when exposed to flow in the presence of extracellular ATP. However, the molecular mechanisms of this process, including the ion channels responsible for the Ca(2+) response, have not been clarified. Here, we demonstrate that P2X4 purinoceptors, a subtype of ATP-operated cation channels, are involved in the shear stress-mediated Ca(2+) influx. Human umbilical vein ECs loaded with the Ca(2+) indicator Indo-1/AM were exposed to laminar flow of Hanks' balanced salt solution at various concentrations of ATP, and changes in [Ca(2+)](i) were monitored with confocal laser scanning microscopy. A stepwise increase in shear stress elicited a corresponding stepwise increase in [Ca(2+)](i) at 250 nmol/L ATP. The shear stress-dependent increase in [Ca(2+)](i) was not affected by phospholipase C inhibitor (U-73122) but disappeared after the chelation of extracellular Ca(2+) with EGTA, indicating that the Ca(2+) increase was due to Ca(2+) influx. Antisense oligonucleotides designed to knockout P2X4 expression abolished the shear stress-dependent Ca(2+) influx seen at 250 nmol/L ATP in human umbilical vein ECs. Human embryonic kidney 293 cells showed no Ca(2+) response to flow at 2 micromol/L ATP, but when transfected with P2X4 cDNA, they began to express P2X4 purinoceptors and to show shear stress-dependent Ca(2+) influx. P2X4 purinoceptors may have a "shear-transducer" property through which shear stress is perceived directly or indirectly and transmitted into the cell interior via Ca(2+) signaling.

A matrix attachment region (MAR)-binding activity due to a p114 kilodalton protein is found only in human breast carcinomas and not in normal and benign breast disease tissues.

A M(r) 114,000 protein (p114) that specifically binds to nuclear matrix attachment DNA (matrix attachment region, MAR) from a breast carcinoma cell line SK-BR-3 was purified to near homogeneity. p114 strongly binds to a wild-type A+T-rich MAR probe with high unwinding propensity with a dissociation constant (Kd) of 10(-9), while it exhibits substantially reduced binding to a mutated A+T-rich non-MAR probe, which lacks unwinding propensity. This binding specificity and affinity is similar to the previously cloned thymocyte-associated MAR-binding protein SATB1. By Southwestern blot analysis, the MAR-binding activity of p114 is detectable in human breast carcinomas but is undetectable in normal breast tissues, benign breast diseases, and immortalized epithelial MCF-10A cells. Thus, the MAR-binding activity of p114 is not merely reflecting cell proliferation, but it strongly associates with breast carcinomas. The p114 MAR-binding activity was found in all 43 human breast carcinoma specimens tested, without exception. Much stronger p114 MAR-binding activity was detected in poorly differentiated than well-differentiated carcinomas. p114 may be a reliable diagnostic and possibly prognostic marker for breast cancer.

Steroid sulfatase expression is an independent predictor of recurrence in human breast cancer.

Steroid sulfatase (STS) hydrolyzes several sulfated steroids such as estrone sulfate, dehydroepiandrosterone sulfate, and cholesterol sulfate. In the present study, we have measured STS mRNA levels in 97 breast cancers by reverse transcription-PCR using a fluorescent primer in the presence of an internal standard RNA and evaluated its association with disease-free and overall survival. The median value was 728.0 amol/ng RNA (range, 0-11,778 amol/ng RNA). Levels were significantly higher in tumors demonstrating lymph node metastasis than in those without nodal involvement (P = 0.033) and in patients who experienced a recurrence during the follow-up period (mean, 40.8 months; median, 39 months) compared with those with no evidence of further disease (mean, 49.2 months; median, 48 months; P = 0.029). No significant associations were found between STS mRNA expression and age, menopausal status, tumor size, histological grade, estrogen receptor status, or postoperative adjuvant therapy. High levels of STS mRNA proved to be a significant predictor of reduced relapse-free survival as a continuous variable (log STS mRNA; P = 0.028). As a dichotomous variable with an optimized cutoff point of 1,240 amol/ng RNA, expression was also associated with a significantly shorter relapse-free survival rate (P = 0.002), but no significant correlation was found between the STS mRNA level and overall survival. Expression was found to be an independent factor for predicting relapse-free survival on multivariate analysis. The results thus support a putative role of STS in breast cancer growth and metastasis.

Upregulatory expression of furin and transforming growth factor-beta by fluid shear stress in vascular endothelial cells.

Furin, a yeast Kex2-family endoprotease, converts many vasoregulatory propeptides, including pro-transforming growth factor (TGF)-beta to their mature forms. We examined whether furin expression is regulated by shear stress in vivo and in vitro. When an arteriovenous shunt was placed between the carotid artery and external jugular vein in rabbits, furin and TGF-beta were highly expressed in shear stress-loaded endothelial cells. Exposure of bovine aortic endothelial cells in culture to shear stress induced furin and TGF-beta expression in a similar manner. Molecular analysis of furin expression in bovine aortic endothelial cells revealed that shear stress increases the furin gene expression at transcriptional levels. Furthermore, TGF-beta itself increased the furin mRNA levels. Shear-mediated furin expression was partly mediated by TGF-beta because shear-induced furin mRNA levels were considerably decreased by overexpression of the truncated form of the TGF-beta type II receptor. Likewise, blockade of furin activity by a furin inhibitor significantly decreased the endothelial production of mature TGF-beta. Taken together, the results indicate that furin expression is induced and maintained by a coordination of shear stress and TGF-beta. Increased furin expression may facilitate the formation of mature TGF-beta, resulting in the enhanced effects of TGF-beta on endothelial cells and vascular smooth muscle cells in the vasculature.

Sprouting from arteriovenous shunt vessels with increased blood flow.

The purpose of this study was to evaluate the effect of increased blood flow on angiogenesis at the large vessels. The arteriovenous (AV) shunt was made on the thigh of male Wistar rats (n = 27) to increase blood flow, wrapped with artificial skin dermis, which consisted of a silicon outer layer, and isolated from surrounding tissues. Blood flow increased from 2.40 +/- 0.77 to 35.8 +/- 8.7 ml min(-1) (14.9 times), and the shear stress index (relative value of shear stress) increased from 10.7 +/- 3.6 to 73.4 +/- 18.1 (6.85 times) 60 min after the shunt formation. Newly formed vessels were observed around the AV shunt loop. Scanning electron micrographs at the AV shunt vessel lumen showed modified endothelial cells at day 7 and a remarkable number of pores at day 14. The volume of newly formed vessels was increased 12 times from day 5 to day 14. The mechanical factor of shear stress was considered the major stimulator of angiogenesis. This is the first report of electron-microscopic observation of sprouts from a large vessel lumen. The new AV shunt model is useful for basic research on angiogenesis at the large vessels in vivo and, furthermore, could generate vascularised tissues with various cultured cells.

Responsiveness of hypophyseal-adrenocortical axis to repetitive administration of synthetic ovine corticotropin-releasing hormone in patients with isolated adrenocorticotropin deficiency.

The primary lesion site in isolated ACTH deficiency was studied in three patients by examining the responses of immunoreactive ACTH to insulin-induced hypoglycemia, lysine vasopressin, and synthetic ovine corticotropin-releasing hormone (CRH). In all patients, no significant changes in immunoreactive ACTH followed insulin-induced hypoglycemia or lysine vasopressin. Fifty micrograms (greater than or equal to 1 microgram/kg BW) of CRH administered as an iv bolus dose daily for 6 consecutive days elicited no significant increase in plasma immunoreactive ACTH, beta-lipotropin, or cortisol levels in all patients. Eight iv bolus injections of 0.63 microgram/kg BW CRH at 4-h intervals also failed to induce a significant response of immunoreactive ACTH to an iv bolus dose of 1 microgram/kg CRH at 36 h in one patient. In contrast, a single bolus dose of 50 micrograms CRH induced a response of plasma immunoreactive ACTH in a patient with Cushing's disease and a patient with Addison's disease. The present results suggest that the primary lesion of isolated ACTH deficiency is not the hypothalamus, but, rather, is located in pituitary ACTH-secreting cells.

Shear stress augments expression of C-type natriuretic peptide and adrenomedullin.

Shear stress is known to dilate blood vessels and exert antiproliferative effects on vascular walls: these effects have been ascribed to shear stress-induced upregulation of endothelium-derived vasoactive substances, mainly nitric oxide and prostacyclin. We have demonstrated the significance of C-type natriuretic peptide (CNP) as a novel endothelium-derived relaxing peptide (EDRP) that shares a cGMP pathway with nitric oxide. Adrenomedullin is a recently isolated EDRP that elevates intracellular cAMP as prostacyclin does. To elucidate the possible role of these EDRPs under shear stress, we examined the effect of physiological shear stress on CNP mRNA expression in endothelial cells derived from the human umbilical vein (HUVECs), bovine aorta (BAECs), and murine lymph nodes (MLECs) as well as adrenomedullin mRNA expression in HUVECs. CNP mRNA was stimulated prominently in HUVECs under shear stress of 15 dyne/cm2 in a time-dependent manner (4 hours, sixfold increase compared with that in the static condition; 24 hours, 30-fold increase). Similar results were obtained in BAECs (4 hours, twofold increase; 24 hours, threefold increase) and MLECs (4 hours, threefold increase; 24 hours, 10-fold increase). Augmentation of CNP mRNA expression that was dependent on shear stress intensity was also observed (5 dyne/cm2, 2.5-fold increase of static; 15 dyne/cm2, 4.5-fold increase). Increased CNP secretion was also confirmed by the specific radioimmunoassay for CNP. Adrenomedullin mRNA expression in HUVECs increased under shear stress of 15 dyne/cm2 in a time-dependent manner (4 hours, 1.2-fold increase of static: 24 hours, threefold increase) and shear stress intensity-dependent manner (15 dyne/cm2, threefold increase compared with that at 5 dyne/cm2). These results suggest that the coordinated augmentation of mRNA expression of these novel EDRPs may constitute shear stress-dependent vasodilator and antiproliferative effects.

Synthesis and antitumor activity of tropolone derivatives. 7. Bistropolones containing connecting methylene chains.

Bistropolone derivatives (4-12) containing differing lengths of linkage between the two tropolone rings were prepared and examined for their antitumor activity in in vitro (KB cell) and in vivo (leukemia P388 in mice) systems. Parent compound 3, related compounds previously prepared, and the new compounds 4-12 were evaluated for inhibitory activity against ribonucleotide reductase by indirect means to measure their effects on the dNTP pool imbalance. Present structure-activity relationship results would suggest that potently active bistropolones in vivo inhibit intracellular ribonucleotide reductase through chelating with the two irons at the two active sites of the enzyme.

Inhibitory effects of uterine endometrial carcinogenesis in Donryu rats by tamoxifen.

The effects of tamoxifen (TAM) on uterine carcinogenesis were investigated in female Donryu rats. The effects were initiated by a single intrauterine treatment with N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) at a dose of 20 mg/kg body weight via the vagina at 10 weeks of age. TAM tubes (cholesterol tubes containing 50% TAM) were implanted into the backs of the rats for 13 months (full TAM group) or for the second-half of this period (half TAM group). In the control group treated with ENNG alone, various proliferative lesions were induced in the uterine endometrium and the incidence of endometrial adenocarcinomas was about 30%. In contrast, the uteri in both TAM-treated groups showed severe atrophy and the incidences of uterine proliferative lesions were limited to a few endometrial hyperplasias in the half TAM group. Most of the vaginas in both TAM-treated groups showed mucification, while cornification was common in the vaginal epithelium of controls. The ovaries demonstrated similar atrophy with cystic follicles and no corpora lutea in all groups. Other estrogen responsive endocrine organs, such as the pituitaries and adrenals, were small in the TAM-treated groups. Serum estrogen levels in the TAM-treated groups were lower than in the control group but progesterone levels did not differ. These results indicated that TAM acts as an anti-estrogen on the adult rat uterus, inhibiting the development of endometrial adenocarcinomas initiated by ENNG.

Time-dependent promotion activity of 17beta-estradiol on uterine carcinogenesis in mice initiated with N-ethyl-N-nitrosourea.

The time-dependent promotion activity of 17beta-estradiol (E2) by initiation with N-ethyl-N-nitrosourea (ENU) on induction of mouse uterine endometrial proliferative lesions was examined. Illumination-induced persistent estrous female CD-1 mice were divided into five groups at 9 weeks of age. At 10 weeks of age, mice in all groups (n=25) were given a single intra-uterine administration of ENU (50 mg/kg), dissolved in polyethylene glycol. Animals in Groups 2 to 5 were then implanted s.c. with an E2 pellet at 9, 11, 14 and 17 weeks of age. The implants were left in place for 8 weeks and then taken out. At the termination of the experiment (week 15 after the ENU-treatment), all surviving mice were killed and the development of uterine proliferative lesions were assessed. All groups demonstrated endometrial hyperplasias and adenocarcinomas and the incidences of the latter in ENU plus E2 treated animals (Groups 2 to 5; 36, 48, 35 and 36%, respectively) were significantly higher compared to 8% for Group 1, without any variation with the age at E2 treatment. However, the incidences of adenocarcinomas plus severe hyperplasias increased from Groups 1 to 5 (28, 40, 56; P<0.05, 61; P<0.05 and 80%; P<0.01, respectively), indicating that promotion effects of E2 on induction of uterine proliferative lesions in the uterine endometrium become more pronounced with the interval after ENU initiation.

Possible mechanisms underlying mammary carcinogenesis in female Wistar rats by nitrofurazone.

Mechanisms underlying mammary carcinogenesis in female rat given nitrofurazone (NF) were examined. Experiment I: female Wistar rats were divided into three groups, and given diets containing 0, 500 or 1000 ppm NF for 5 weeks. At terminal sacrifice, body and uterus weights were the same in all groups, although ovary weights in NF-treated animals were significantly higher than in control animals, the increase being dose-dependent. Serum prolactin (PRL) concentrations in NF-treated groups at 17:00 h on the day of proestrus were also dose-dependently higher than that in control group. Experiment II: a two-stage rat mammary carcinogenesis protocol was performed. Rats were divided into four groups, Groups 2 and 4 being treated by 9,10-dimethyl-1,2-benzanthracene (DMBA) at 7-weeks-old. Groups 3 and 4 were given diets containing 1000 ppm of NF between 8 and 27 weeks of age, when all surviving rats were autopsied. DMBA-treated animals demonstrated mammary tumors at high incidences, 91.1 and 90.5%, respectively, in Groups 2 and 4, no tumor development being observed without the initial carcinogen exposure (Groups 1 and 3). The mean tumor weights and the mean numbers of tumors per tumor-bearing rats in Group 4 were increased as compared with Group 2, albeit not significantly. Serum PRL (proestrus day at 17:00 h) and progesterone (PG) (diestrus day at 10:00 h) concentrations in NF-treated animals (Groups 3 and 4) were significantly higher than those in untreated rats (Groups 1 and 2). These results suggest that increases of serum PRL and PG concentrations by NF may be the most important factors regarding its promotion of mammary tumor growth and/or enhancement of mammary carcinogenesis in female rats.

Hepatotoxicity and consequently increased cell proliferation are associated with flumequine hepatocarcinogenesis in mice.

It has been reported that flumequine (FLU) induces hepatic tumors in mice when given orally for 18 months. We investigated possible underlying mechanisms using a two-stage mouse hepatocarcinogenesis model. After initiation with a single intraperitoneal injection of 100 mg/kg body weight diethylnitrosamine (DEN) or saline, male CD-1 mice were given 4000 ppm FLU in the diet or 500 ppm phenobarbital (PB) in drinking water for 9, 19, 24 or 30 weeks. Toxicity, evidenced by centrilobular swollen and polar hepatocytes with fatty droplets, infiltration of inflammatory cells and increased numbers of mitosis in hepatocytes, was apparent in the livers of mice treated with FLU at all time points, but its severity declined towards the termination. FLU did not induce cytochrome P-450 enzymes such as 1A1, 2B1 and 3A2 as assessed immunohistochemically, while positive expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was increased in hepatocytes of both DEN + FLU and FLU groups compared with the relevant controls. In animals given PB, eosinophilic swelling of hepatocytes was prominent, and the hepatocytes showed strongly positive reactions for CYP 1A1 and 3A2. Altered cell foci were induced in the livers of FLU-treated animals both with and without DEN initiation, especially the former, and their development paralleled the degree of hepatic toxicity. These results suggest that FLU hepatocarcinogenicity in mice is dependent on hepatotoxic damage and consequently increased cell proliferation. Oxidative damage to DNA may also be a crucial factor.

Transplacental administration of diethylstilbestrol (DES) causes lesions in female reproductive organs of Donryu rats, including endometrial neoplasia.

The effects of transplacental administration of diethylstilbestrol (DES) on female reproductive organs were investigated using Donryu rats. The animals were given subcutaneous injections of DES dissolved in olive oil at doses of 0.01 or 0.1 mg/kg on days 17 and 19 of gestation. In female offspring, clinical signs, body weights and estrous cycles were continuously assessed until all survivors were killed at month 18. A low mean litter size and shortening of period of pregnancy were recognized in the 0.1 mg/kg group. Disorder and/or suspension of the estrous cycle (so called persistent estrus) also appeared very early in the 0.1 mg/kg group. Macroscopically, the incidences of hypoplasia of the oviduct, cystic dilatation of the uterus and small size of the uterine cervix were higher in the 0.1 mg/kg group than those in the control group. Histologically, in the ovary, the incidence and degree of atrophy were increased in both 0.01 and 0.1 mg/kg groups. In the uterus, total incidences of endometrial hyperplasias were about the same in all groups. However, endometrial adenocarcinomas were dose-dependently increased in the treated groups, the incidence in the 0.1 mg/kg group being significant, compared to that in the control. In the vagina, mucification was more prominent in the treated animals, especially at the higher dose, but no tumors were observed. The present results indicate that prenatal exposure to DES can produce uterine adenocarcinomas in rats, as reported earlier for mice, although its carcinogenic activity is not so strong. Increase of endometrial adenocarcinoma incidence might depend on hormonal imbalance resulting from the ovarian atrophy due to transplacental treatment of DES.

Salmon gonadotropin IIbeta subunit promoter contains multiple DNA elements responsible for stimulation by gonadotropin-releasing hormone through protein kinase C-dependent and -independent pathways.

Gonadotropin-releasing hormone (GnRH) stimulates gonadotropin (GTH) production by activating GTH subunit gene transcription. In salmonid fish, the expression of the beta subunit gene of GTH II (sGTH IIbeta) is stimulated by GnRH at the final stages of reproduction. DNA elements required for the GnRH stimulation were examined by analyzing sGTH IIbeta promoter activity by transfection studies in a gonadotrope-derived cell line, alphaT3-1. A GnRH analog (GnRHa) specifically stimulated the sGTH IIbeta promoter (3358 bp) expression 3.6-fold, while phorbol myristate acid (PMA) stimulated it 6.2-9-fold. Analysis of a series of 5'-deletion mutants has revealed that a proximal region (-258 to -199) was important in GnRHa stimulation through protein kinase C (PKC)-independent signal transduction pathways, because an internal deletion mutant (delta(246 - 217)/3358) showed a significant decrease in the level of GnRHa stimulation, but showed no change in stimulation by PMA. A large upstream region (-3358 to -1260) showed an enhancing activity of the GnRHa stimulation, and a far upstream 530 bp segment in this region (-3358 to -2829) may be responsible for this activity. The present results suggest that sGTH IIbeta gene may be controlled by GnRH through multiple DNA elements including those responsive to PKC-dependent and -independent signal transduction pathways.

Genetic structure of the five-factor model of personality in a Japanese twin population.

Dimensional approaches have been used to describe the fundamental dimensions that underlie the entire domain of normal and pathological personality. We tested the five factor model of personality structure in a sample of Japanese twins, to clarify the contributions of genetic and environment. The revised NEO personality inventory (NEO-PI-R) was administered to 251 twin pairs, ranging in age from 15 to 27 years of age. The NEO-PI-R is a 240-item questionnaire which was developed to assess the dimensions of personality. Univariate genetic analysis showed that the AE model in which phenotypic covariances are explained only by additive genetic (A) and nonshared environment (E) is still a plausible model, and that the relative proportion of genetic influence was comparable to that reported by Loehlin (1992). Multivariate genetic analysis of the Japanese data suggested/revealed that the five factors are genetically dependent on each other and one common genetic factor mediates their interdependence. Previous studies have assumed that they are phenotypically independent and robust. Although there are sampling biases in the present study, it is noteworthy that the results for all five factors depicted by the NEO-PI-R were comparable to those reported by Western researchers, and the genetic structure of the five-factor model is complex.

Genomic structure of the spermatid-specific hsp70 homolog gene located in the class III region of the major histocompatibility complex of mouse and man.

The Hsc70t gene is a Hsp70 homolog gene expressed constitutively in spermatids in mice. This gene is linked to two heat-inducible Hsp70 genes, Hsp70.1 and Hsp70.3, located in the MHC class III region. The syntenic region of human chromosome 6 contains the HSPA1B, HSPA1A, and HSPA1L genes. Here, we have isolated a HSPA1L cDNA clone from human testicular cells. The HSPA1L gene contained an intron 13 bp upstream of the initiating ATG. A similar genomic structure was found in the Hsc70t gene. The transcription initiation site of the Hsc70t gene was located at ca. 600 bp upstream of the heat-inducible Hsp70.3 gene, linked head-to-head. Sequence alignment of the mouse and human genes revealed that the human HSPA1L and HSPA1A genes were orthologous to the mouse Hsc70t and Hsp70.3 genes, respectively. Conserved sequence stretches observed in the 5' flanking region and the first exon of the spermatid-specific Hsp70 gene may be involved in regulation of the specific gene expression.

Down-regulation of vascular adhesion molecule-1 by fluid shear stress in cultured mouse endothelial cells.

This study was undertaken to determine whether blood flow modulates the adhesive property of vascular endothelial cells to lymphocytes and, if it does, what adhesion molecules are involved. Cultured mouse endothelial cells were exposed to medium flow in a parallel plate chamber, and binding assay using fluorescence-labeled lymphocytes was carried out. The adhesion rate of endothelial cells to lymphocytes, which was high in the static control state, decreased when exposed to shear stress (1.5 dynes/cm2) for 6 h. The treatment of static endothelial cells with a monoclonal antibody of vascular cell adhesion molecule-1 (VCAM-1) depressed the adhesion rate to the same extent as that caused by flow, while monoclonal antibodies of CD44 and intercellular adhesion molecule-1 had no effect on it. Flow cytometric analysis revealed that the application of flow decreased markedly the amount of VCAM-1 expressed on the cell surface. A reverse transcriptase-polymerase chain reaction of mRNA showed that flow depressed VCAM-1 mRNA levels. These results suggest that blood flow can modulate the adhesive property of endothelial cells to lymphocytes via affecting the surface expression of adhesion molecules, e.g., down-regulation of VCAM-1.