Mating type switching in yeast controlled by asymmetric localization of ASH1 mRNA

Cell divisions that produce progeny differing in their patterns of gene expression are key to the development of multicellular organisms. In the budding yeast Saccharomyces cerevisiae, mother cells but not daughter cells can switch mating type because they selectively express the HO endonuclease gene. This asymmetry is due to the preferential accumulation of an unstable transcriptional repressor protein, Ash1p, in daughter cell nuclei. Here it is shown that ASH1 messenger RNA (mRNA) preferentially accumulates in daughter cells by a process that is dependent on actin and myosin. A cis-acting element in the 3'-untranslated region of ASH1 mRNA is sufficient to localize a chimeric RNA to daughter cells. These results suggest that localization of mRNA may have been an early property of the eukaryotic lineage.

LPS-induced delayed myocardial adaptation enhances acute preconditioning to optimize postischemic cardiac function

Myocardial tolerance to ischemia and reperfusion (I/R) injury can be achieved by either acute or delayed cardioprotective mechanisms. Ischemic preconditioning has been demonstrated to be a powerful acute cardioprotective stimulus. We have reported that lipopolysaccharide (LPS) pretreatment induces delayed myocardial adaptation to I/R injury. To optimize myocardial protection, we examined the ability of delayed myocardial adaptation to enhance acute ischemic preconditioning in the isolated working rat heart. Male Sprague-Dawley rats were divided into control, acute [transient ischemia (TI); 5-min global ischemia, 37 degrees C], delayed (LPS; 500 micrograms/kg i.p.), or combined (LPS + TI) cardioprotective groups. Delayed cardioprotection involved LPS injection 72 h before heart isolation. All hearts were subjected to 20-min global ischemia (37 degrees C) and 30-min reperfusion. Coronary effluent collected during reperfusion was assayed for creatine kinase (CK) activity. Both TI and LPS treatment improved postischemic aortic flow recovery (29 +/- 4.5 and 44 +/- 4.0%, respectively; P < 0.05, LPS vs. TI) compared with control hearts (11 +/- 2.2%; P < 0.05, TI or LPS vs. control). When TI was applied to LPS-treated hearts (LPS + TI), aortic flow recovery was further enhanced (57 +/- 3.8%; P < 0.05 vs. TI or LPS alone). CK release during 20 and 30 min of reperfusion was decreased in all treated hearts compared with control hearts (P < 0.05). These results indicate that delayed myocardial adaptation and acute ischemic preconditioning independently activate protective mechanisms against ischemia. Enhanced protection occurs when induced delayed mechanisms are combined with acute cardioprotective stimuli, which optimize postischemic myocardial function and reduce myocellular necrosis.

[The setting up of human serum calcitonin radioimmunoassay and its clinical application]

This study deals with the setting up of human serum calcitonin radioimmunoassay (hCT-RIA) using the high titer and specific antibody which was prepared by our own laboratory. The final dilution of the antibody titer was 1:1,200,000 when the binding rate of Bo/T was 30%. The antibody's affinity constant (Kd) was 2.25 x 10(11) L/M. No cross reaction was found between the antibody and the following eight different peptide hormones and proteins, viz.: TSH, T3, T4, ACTH, PTH, BGP, Insulin and Gastrin. The coefficients variation of intra and inter assay were 3.2% and 9.0%, respectively. The mean recovery rate of CT was 99.8%. The sensitivity of this assay was 9.4 pg/ml. The examination of this methodology showed that all its indices met the demands of RIA. There was no difference in the mean value of serum CT between the two sexes in 232 normal subjects, but the serum CT concentration in those aged of sixty and over of men and women, were much lower than those aged of fourty group. Mean CT concentration was low in the patients with primary osteoporosis, but were significantly higher in those suffering from medullary thyroid carcinoma, primary hyperparathyroidism crisis and chronic renal failure.

[Evaluation of oral glucose tolerance test in the assessment of reserved function of liver for patients with hepatocellular carcinoma]

The aim of this study was to evaluate oral glucose tolerance test(OGTT)in the assessment of reserved function of liver for predicting the tolerability of patients to hepatectomy and hence provided a criteria for selecting the candidates for undergoing hepatectomy, since the majority of hepatocellular carcinoma (HCC) patients were associated with posthepatitis cirrhosis. The preoperative and postoperative OGTT and liver biopsy for pathological investigation were carried out in 62 cases of hepatecomized patients and 49 cases of unresected patients for comparison. The results revealed that the patients whose preoperative OGTT curve was of P type recovered uneventfully after hepatectomy, but those whose curve was of L type of tolerated poorly to hepatectomy and were liable to postoperative hepatic failure and complications. The severity of cirrbosis in those poor risk patients fell to C III or C IV histological degree. 29 patients with intermediate feature of OGTT curve between P type and L type, i.e. I type underwent regional vascular occlusion at hepatic hilus as hepatectomy, and infusion of Danshen extract solution before vascular occlusion to prevent hepatocytes from reperfusion injury. Of them, 20 recovered uneventfully, 8 suffered from complications such as ascites and/or juandice, and 1 died within 1 month after operation. The followup study showed that the survival time of patients with P type OGTT curve was longer than that of I type, and the latter was longer than that of L type. The pattern of OGTT curve could change from preoperative P type to postoperative L type, depending on the severity of vascular interruption of liver and the ischemic injury to hepatocytic mass in operation.

Hyperplasia of lymphatic vessels in VEGF-C transgenic mice

No growth factors specific for the lymphatic vascular system have yet been described. Vascular endothelial growth factor (VEGF) regulates vascular permeability and angiogenesis, but does not promote lymphangiogenesis. Overexpression of VEGF-C, a ligand of the VEGF receptors VEGFR-3 and VEGFR-2, in the skin of transgenic mice resulted in lymphatic, but not vascular, endothelial proliferation and vessel enlargement. Thus, VEGF-C induces selective hyperplasia of the lymphatic vasculature, which is involved in the draining of interstitial fluid and in immune function, inflammation, and tumor metastasis. VEGF-C may play a role in disorders involving the lymphatic system and may be of potential use in therapeutic lymphangiogenesis.

The RNA-binding protein, TB-RBP, is the mouse homologue of translin, a recombination protein associated with chromosomal translocations

The mouse RNA-binding protein, TB-RBP, suppresses translation in vitro and attaches mRNAs to microtubules by binding to conserved elements in the 3' untranslated regions of specific mRNAs. We have now purified TB-RBP from testicular and brain cytoplasmic extracts and cloned its cDNA. We find that the mouse TB-RBP cDNAs contain an open reading frame of 228 amino acids with a leucine zipper domain within its C terminus, a transmembrane helix, and a group of putative phosphorylation sites. TB-RBP shows 99% identity to the human protein, translin, a recombination hotspot-binding protein associated with chromosomal translocations [Aoki, K., Suzuki, K., Sugano, T., Tasaka, T., Nakahara, K., Kuge, O., Omori, A. & Kasai, M. (1995) Nat. Genet. 10, 167-174]. As shown for translin, TB-RBP also binds to single-stranded DNAs containing a broad range of consensus sequences, many of which are similar to the Y and H RNA-binding sequences. Recombinant TB-RBP was synthesized and an antiserum was prepared against the recombinant protein. The identity between translin and TB-RBP was confirmed by demonstrating that immunoprecipitation of TB-RBP from testicular extracts abolished formation of the RNA-TB-RBP complex. Based upon its DNA binding to target sequences in clustered breakpoint regions, we propose that TB-RBP may be involved in DNA recombination or DNA repair in male germ cells.

Polymorphisms of vitamin D receptor gene and its association with bone mineral density and osteocalcin in Chinese

OBJECTIVE

To explore the distribution frequencies of vitamin D receptor (VDR) gene polymorphisms in Chinese and the relationship between VDR genotypes and bone mineral density (BMD) or serum osteocalcin level in Chinese women.

METHODS

Polymorphisms of VDR gene were analyzed by polymerase chain reaction (PCR) to amplify the DNA sequence and three restriction enzymes (namely BsmI, ApaI and TaqI) to digest the PCR products in 223 subjects. Some of the VDR genotypes were also confirmed by Southern hybridization analysis. BMD was measured at the spine and proximal femur by dual-energy X-ray absorptiometry (DEXA). Serum osteocalcin concentrations were determined by radioimmunoassay.

RESULTS

Chinese had high frequencies of "b,a,T" alleles, 95%, 75% and 95% respectively, which were much different from Caucasians. "BB" or "AA" genotype had tendency for higher BMD at some sites in the group of young women, whereas in the group of postmenopausal women, "bb" or "aa" genotype had relationship with lower BMD at femoral neck and trochanter. Furthermore, no relationship were found between VDR genotypes and the serum osteocalcin level in Chinese women.

CONCLUSIONS

Allele frequencies of VDR gene in Chinese are different from those in Caucasians. VDR gene polymorphisms are associated with BMD in Chinese, but in a different pattern from other reports. Further study on predicting function of VDR for osteoporosis is necessary.

Protein kinase C isoform diversity in preconditioning

Protein kinase C (PKC) appears to be a common intracellular effector and signal collector during cardiac preconditioning; however, it remains unknown whether agonists that activate different PKC isoforms are also linked to select aspects of myocardial protection. Using agonists that are known to activate unique combinations of PKC isoforms, we interrogated the relationship between isoform activation and the different aspects (pH, function, and viability) of endogenous myocardial protection. To study this, isolated rat hearts were subjected to ischemia-reperfusion (I/R) (20 min/40 min), without (control = Ctrl) or with receptor-dependent [phenylephrine (PE), 50 microM; adenosine (ADO), 125 microM] or -independent [phorbol myristate acetate (PMA), 100 nM] activation of PKC. Function, pH, and viability were assessed by rate pressure product (%RPP) and coronary flow (CF; ml/min), by 31P NMR, and by CF creatine kinase (CK; U/liter) leak, respectively. PMA, which activates PKC delta but not eta, resulted in intracellular pH (pHi) and viability protection, but did not protect against postischemic myocardial stunning. ADO, which activates PKC eta but not delta, protects against stunning, but not acidosis or necrosis. PE, which activates PKC delta and eta, provided global myocardial protection against necrosis, acidosis, and stunning. Different PKC isoforms may be linked to distinct aspects of myocardial protection. Targeted activation of PKC isoforms may allow precise mechanistic application of preconditioning-like myocardial protection.

Upregulation of aquaporin-2 water channel expression in chronic heart failure rat

Aquaporin-2 (AQP2) mediates vasopressin-regulated collecting duct water permeability. Chronic heart failure (CHF) is characterized by abnormal renal water retention. We hypothetized that upregulation of aquaporin-2 water channel could account for the water retention in CHF. Male rats underwent either a left coronary artery ligation, a model of CHF, or were sham operated. 31-33 d after surgery, mean arterial pressure (MAP) and cardiac output were measured in conscious animals, and the animals were killed 24 h later. Cardiac output (CO) and plasma osmolality were significantly decreased and plasma vasopressin increased in the CHF as compared to the sham-operated rats. Both mRNA and protein AQP2 were significantly increased in the kidneys of the CHF rats. The effect of oral administration of a nonpeptide V2 vasopressin receptor antagonist, OPC 31260, was therefore investigated. OPC 31260 induced a significant increase in diuresis, decrease in urinary osmolality, and rise in plasma osmolality in the OPC 31260-treated CHF rats as compared to untreated CHF rats. The mRNA and protein AQP2 were significantly diminished in both cortex and inner medulla of the treated CHF rats. In conclusion, an early upregulation of AQP2 is present in CHF rats and this upregulation is inhibited by the administration of a V2 receptor antagonist. The results indicate a major role for vasopressin in the upregulation of AQP2 water channels and water retention in experimental CHF in the rat.

A keratin K10 gene mutation in a Japanese patient with epidermolytic hyperkeratosis

Epidermolytic hyperkeratosis (EHK), or bullous congenital ichthyosiform erythroderma, is characterized by generalized erythroderma, ichthyosiform skin and blistering, and is caused by an aberration of the keratin intermediate filaments. In this study, we examined keratin K10 and 1 gene mutations in a Japanese EHK patient who had severe ichthyosiform erythroderma at birth and developed subsequent blistering. The patient had a G to A transition at codon 156 of the keratin K10 gene, which resulted in an arginine (Arg)-->histidine (His) substitution in the helix initiation peptide of the highly-conserved 1A domain in keratin K10. This is the first mutation report of a Japanese patient with EHK, although the position and mode of the mutation identified here did not differ from those in reported Western cases.

[Gama hydroxybutyrate sodium (gama-OH)-diazepam combined anaesthesia for cleft palate repair in children below 3 years old]

To investigate the effect of Gama-OH-Diazepam combined anaesthesia for cleft palate repair in children below 3 years old.

METHODS

Heart rates were measured in 120 children at induction, at 5 minutes after endotrocheal intubation, at finishing of operation, and at 5 minutes after extubation. In addition, changes of SpO2 was randomly detected in 10 children.

RESULTS

Heart rate decreased after intubation, increased when operation was completed and decreased again after extubation. SpO2 of all stages were in the normal range.

CONCLUSIONS

This method of anaesthesia is suitable for cleft palate repair in children below 3 years old, with the advantages of little effect on the children's circulatory and respiratory systems, and being easy to perform and control.

In vivo transfer of a foreign gene to keratinocytes using the hemagglutinating virus of Japan-liposome method

The hemagglutinating virus of Japan (HVJ)-liposome method involves the entrapment of DNA and nuclear protein within liposomes and the use of HVJ to enhance liposome fusion with cell membranes. This method has been used successfully for in vivo gene transfer to various types of tissue. In this study, we investigated whether this method transfers genes effectively to normal and malignantly transformed keratinocytes in vivo. We applied HVJ-liposome complex (HLC) containing the beta-galactosidase gene to the tape-stripped skin of hairless rats and detected the enzyme activity in the keratinocytes of the treated skin. Comparison of this method with the naked DNA injection method, which was shown recently to be useful for in vivo gene transfer to keratinocytes, demonstrated that the transfer efficiency of the latter was about 5 times higher than that of the former. We assessed the efficacy of the HVJ-liposome method for gene transfer to transformed keratinocytes by examining the effect of HLC containing the herpes simplex virus thymidine kinase gene on the growth of mouse squamous cell carcinomas. Local injection of HLC into the tumors followed by administration of ganciclovir to mice resulted in tumor growth inhibition. These results indicate that the HVJ-liposome method is suitable for in vivo gene transfer to keratinocytes; also that this method may prove a good tool for basic research into keratinocyte biology and future keratinocyte gene therapy.

Hemorrhage induces acute cardioadaptation to ischemia-reperfusion by an alpha1-adrenoceptor-mediated, protein synthesis-independent mechanism

Hemorrhage and resuscitation (H-R) has been recognized as an exclusively destructive process that results in multiple organ dysfunction. Although it is well established that endogenous adaptation mechanisms exist, it is unknown whether H-R induces endogenous adaptive/protective mechanisms. Furthermore, alpha1-adrenoceptors and de novo protein synthesis have been variably implicated in myocardial adaptation responses. This study tests the hypothesis that H-R results in myocardial adaptation by a mechanism mediated by alpha1-adrenoceptors and requiring de novo protein synthesis. The aims of the present study were to determine 1) whether H-R stress results in acute cardioadaptation to subsequent global, normothermic ischemia-reperfusion (I-R); 2) whether H-R-induced endogenous adaptation is mediated by alpha1-adrenoceptors; and 3) whether H-R-induced endogenous adaptation requires de novo protein synthesis. Rats were hemorrhaged and resuscitated, sham operated, or neither, with and without prior alpha1-adrenoceptor or protein synthesis inhibition. Hearts were then isolated and subjected to a second insult consisting of global, normothermic I-R (20 min ischemia-40 min reperfusion). The results show that antecedent H-R improved post-I-R left ventricular developed pressure, compliance, coronary flow, and decreased reperfusion creatine kinase loss (P < 0.05, analysis of variance with Bonferroni-Dunn). H-R-induced adaptation was abolished by prior alpha1-adrenoceptor blockade (prazosin, 0.5 mg/kg ip); however, inhibition of de novo protein synthesis (cyclohexamide, 1.0 mg/kg ip) did not affect H-R-induced acute adaptation. This study constitutes the initial demonstration that H-R induces endogenous cardioadaptation, which is mediated by an alpha1-adrenergic signaling pathway, but does not require de novo protein synthesis.

Nitric oxide synthase is not involved in cardiac contractile dysfunction in a rat model of endotoxemia without shock

Endotoxin and proinflammatory cytokines induce nitric oxide synthase (NOS), and nitric oxide (NO) plays an important role in promoting endotoxin shock. However, the role of NOS in endotoxemic cardiac contractile dysfunction is not defined. To determine whether endotoxemic cardiac contractile dysfunction involves NOS, the present study used a rat model of endotoxemia without shock and examined the effects of glucocorticoids (dexamethasone, a potent inhibitor of inducible NOS, iNOS, expression), isoform nonselective NOS inhibitor (NG-monomethyl-L-arginine, L-NMA) and iNOS selective inhibitor (S-methylisothiourea sulfate, SMT) on cardiac contractile dysfunction. A sublethal dose of endotoxin (from Salmonella typhimurium, .5 mg/kg, i.p.) was given to adult rats, and left ventricular developed pressure (LVDP) examined by Langendorff technique was attenuated in hearts isolated at 4 or 6 h (66.7 +/- 3.4 and 60.3 +/- 5.5 mmHg, respectively, p < .05 vs. 102 +/- 2.4 mmHg in saline control) after endotoxin treatment. Pretreatment of rats with dexamethasone (4.0 mg/kg, i.v., -30 min) partially abolished endotoxin-induced contractile dysfunction at 6 h (LVDP 87.6 +/- 6.8 mmHg, p < .05 vs. endotoxin alone at 6 h). However, pretreatment with L-NMA (30 mg/kg, i.v., -5 min) or SMT (5.0 mg/kg, i.v., -1 min) failed to prevent the contractile dysfunction. Moreover, infusion of L-NMA or SMT in vitro could not restore contractile function in hearts isolated at 6 h after endotoxin treatment. In contrast, inhibition of NOS with L-NMA or SMT in vitro further attenuated coronary flow in endotoxin-treated hearts. Thus, endotoxemic cardiac contractile dysfunction in this non-shock rat model may not involve NOS, and inhibition of NOS may deteriorate coronary perfusion in endotoxemic heart.

[The frequencies of the vitamin D receptor gene alleles in adults of Han nationality in Beijing area]

Vitamin D receptor (VDR) gene is considered as one of candidate genes related to the genetic basis of bone and mineral metabolism. In order to determine VDR genotypes, we analysed the polymorphisms, or genotypes of Bsm I, Apa I, and Taq I restriction enzymes, by PCR technique in 223 unrelated healthy adults of Han nationality in Beijing area. Some of the VDR genotypes were also confirmed by Southern blotting analysis. We discovered that Chinese had high frequencies of b, a, T alleles, as high as 95%, 75%, and 95% respectively, which were different from those in Caucasians and Japanese, but similar to those in Koreans (P > 0.05). This difference gave us further insight into the different pathogeny of osteoporosis in various ethnics.

[Antioxidative effect of constituents of herba Epimedii (ESPS)]

Herba Epimedii is a traditional Yang invigorating Chinese herb widely used in clinic. The experimental results have shown that ESPS obviously increases superoxide dismutase(SOD) activity of red cells and liver in aged mice and rats, and increases glutathione peroxidase(GSH-Px) activity of red cells in aged mice. On the other hand, ESPS obviously helps to reduce the content of serum and liver lipoperoxide(LPO) in aged mice and rats, as well as the content of lipofuscin(LF) in cardiac muscle of aged mice. The results suggest that being helpful in increasing SOD and GSH-Px activities and inhibiting the formation of LPO and LF, ESPS may be a good antiageing agent.

[Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography]

Spinal BMD was measured by QCT in 445 normal individuals aged 10-80 including 190 males and 255 females, which were divided into age-groups by every ten years. Statistic results showed that peak bone mass reached at 10-19 age-group for both male and female and that BMD assessed by QCT in females was not lower than that in males and BMD declined with increasing age. In females, BMD results in this study were different from those in USA. An acceleration bone loss was predominantly shown in the period after 40-49 age group. Among many factors related to bone loss, we consider that estrogen change may play a most important role for the remarkable bone loss in our country.

Neutrophil depletion attenuates endotoxin-induced dysfunction of cGMP-mediated pulmonary vasorelaxation

The effect of neutrophil depletion on endotoxin-induced dysfunction of guanosine 3',5'-cyclic monophosphate (cGMP)-mediated pulmonary vasorelaxation was studied in rats. Two mechanisms of neutrophil depletion were used: vinblastine (0.75 mg/kg iv) and rabbit anti-rat neutrophil antiserum (0.15 ml iv). Concentration-response curves were generated (10(-9) to 10(-6) M) for acetylcholine (ACh), A-23187, and sodium nitroprusside (SNP) in isolated pulmonary arterial rings preconstricted with phenylephrine 6 h after endotoxin (20 mg/kg ip). Absolute neutrophil count was significantly lowered from 1,050 +/- 206 (neutrophils/ml; mean +/- SE) in controls to 100 +/- 41 by vinblastine and to 50 +/- 29 by antiserum. Endotoxin produced histological evidence of pulmonary vascular endothelial damage and significantly increased lung neutrophil accumulation (myeloperoxidase assay, 5.1 +/- 0 vs. 1.2 +/- 0.1 in controls; 0.1 +/- 0.1 and 0.8 +/- 0.0 U/g lung wt after endotoxin in neutrophil-depleted rats by vinblastine and antiserum, respectively). Endotoxin produced significant impairment of endothelium-dependent cGMP-mediated pulmonary vasorelaxation by receptor-dependent (ACh) and -independent (A-23187) pathways as well as endothelium-independent relaxation (SNP). Neutrophil depletion significantly attenuated the endotoxin-induced impairment of all three of these mechanisms. We conclude that neutrophils contribute to endotoxin-induced impairment of GMP-mediated pulmonary vasorelaxation.

[Effect of active constituents of Herba Epimedii on hypothalamic monoamine neurotransmitters and other brain functions in aging rats]

The active constituents of Herba Epimedii can raise the hypothalamic monoamine neurotransmitters levels in aging male rats and improve the learning and memory in aging rats and mice. It can also inhibit the activities of AchE both in brain tissues and whole blood in mice.

Endotoxin induces cardiac HSP70 and resistance to endotoxemic myocardial depression in rats

Endotoxin (bacterial lipopolysaccharide, LPS) depresses myocardial function. However, heat shock and sublethal LPS can confer cardiac resistance to postischemic dysfunction. We hypothesized that a prior exposure to LPS stress induces the expression of cardiac heat shock protein 70 (HSP70) and resistance to endotoxemic myocardial depression. Moreover, induction of HSP70 by hyperthermia should also increase cardiac resistance to LPS toxicity. LPS (500 micrograms/kg ip) depressed rat left ventricular developed pressure (LVDP) maximally at 6 h (58.4 +/- 3.72 vs. 101 +/- 1.46 mmHg in saline control, P < 0.01), and myocardial contractile function recovered at 24 h. In rats pretreated with LPS 24 h earlier, subsequent LPS exposure did not depress LVDP (97.0 +/- 3.53 mmHg at 6 h, P < 0.01 vs. single exposure). Both LPS and hyperthermia (42 degrees C, 15 min) induced HSP72 mainly in the cardiac interstitial cells, including macrophages at 24 h after treatment. When hyperthermia-pretreated animals were similarly challenged with LPS, myocardial depression at 6 h was partially abrogated (LVDP 80.1 +/- 5.67 vs. 62.2 +/- 4.91 mmHg in sham+LPS group, P < 0.01). We conclude that LPS induces HSP70 in rat heart and that an exposure to LPS or heat stress confers cardiac resistance to endotoxemic myocardial depression.

Clinical application of Omniplane transesophageal echocardiography

One hundred and twenty-four patients with heart disease (75 cases of rheumatic heart disease, 26 cases of congenital heart disease, 13 cases of aortic disease and 10 cases of other disease) were examined by Omniplane transesophageal echocardiography (TEE). The result showed that Omniplane TEE transducer can be rotated from 0 degree to 180 degrees in probe and had the advantages of broader scope, obtaining more information, less stimulation to esophagus and easy to manipulate. It suggests that Omniplane TEE is a efficient technique in clinical diagnosis and can be extensively used in the future.