[The effects of phorbol 12-myristate 13-acetate and microcystine-LR on calcium channel in resistance vascular smooth muscle cells in SHRsp]

OBJECTIVE

To investigate the effects of phorbol 12-myristate 13-acetate (PMA) and microcystine-LR (MCYST-LR) on the whole-cell barium currenta of voltage-dependent calcium channels (VDCs) of the resistance vascular smooth muscle cells (VSMC) from the A4-A5 branches of mesenteric artery in stroke-prone spontaneously hypertensive rats (SHRsp) and its normotensive control Wistar rats.

METHODS

Using the whole-cell Ba2+ current recording of the patch clamp technique.

RESULTS

It was found that PMA, a protein kinase C (PKC) agonist or MCYST-LR, a protein phosphatase IA and IIA inhibitor by which the enhancement of phosphorylation induced could apparently activate the VDCs of the visceral resistance VSMC.

CONCLUSIONS

This activation would be significantly potentiated during hypertension, in which the increase of L-type calcium channel openings induced by PMA was obviously manifest, as the T-type calcium channel activity weakly potentiated. In normotensive Wistar rats, the increase of T-type calcium channel openings was greater than that of SHRsp. However, the effect of MCYST-LR appeared that only the increase of L-type calcium channel current in SHRsp was significant. It is suggested that the action of PKC and/or phosphorylation on the different components of calcium currents should be emphasized in the investigation of the mechanism in the increase in peripheral resistance during hypertension.

[Sequence analysis of Ad7 vaccine strain 87 mu-97.4 mu fragment]

Adenovirus 7 vaccine strain(Ad7v) possesses potentiality to be used as a vector for producing recombinant vaccine. In order to construct Ad7 vector, the nucleotide sequence of a 3698 bp fragment(87 to 97.4 mu) of the virus DNA was analysed. The fragment encodes three ORFs namely, one ORF of early region 4(E4), one ORF of early region 3 and one ORF of fiber protein. The predicted amino acids of three ORFs(ORF 8.1 kD, 42.8 kD and 10.3 kD) share 33%, 43% and 44% homology with Ad2 E4 corresponding regions (ORF 3, ORF 4 and ORF 6/7) respectively. A comparison of the nucleotide and amino acid sequences of those fiber ORF demonstrated a higher homology between Ad7v and prototype strains of Ad7v than those between Ad7v and Ad7h. The Ad7v E3 15.4 kD protein shares 86%, 88%, 90% and 98.5% amino acid homology with the equivalent region of ad7h E3 15.3 kD protein, Ad4 E3 region 15 kD protein, Ad3 E3 15.3 kD and Ad7p E3 15.3 kD protein protein respectively, but only 68% with Ad2 E3 14.7 kD protein.

Effects of carbon source on expression of F0 genes and on the stoichiometry of the c subunit in the F1F0 ATPase of Escherichia coli

Expression of the genes for the membrane-bound F0 sector of the Escherichia coli F1F0 proton-translocating ATPase can respond to changes in metabolic conditions, and these changes are reflected in alterations in the subunit stoichiometry of the oligomeric F0 proton channel. Transcriptional and translational lacZ fusions to the promoter and to two F0 genes show that, during growth on the nonfermentable carbon source succinate, transcription of the operon and translation of uncB, encoding the a subunit of F0, are higher than during growth on glucose. In contrast, translation of the uncE gene, encoding the c subunit of F0, is higher during growth on glucose than during growth on succinate. Translation rates of both uncB and uncE change as culture density increases, but transcription rates do not. Quantitation of the c stoichiometry shows that more c subunits are assembled into the F1F0 ATPase in cells grown on glucose than in cells grown on succinate. E. coli therefore appears to have a mechanism for regulating the composition and, presumably, the function of the ATPase in response to metabolic circumstances.

[Effects of GTP gamma S and GDP beta S on calcium channels of resistance vascular smooth muscle cells in SHRsp]

OBJECTIVE

To investigate the effects of GTP gamma S and GDP beta S on the whole-cell barium currents of voltage-dependent calcium channels (VDC) of the vascular smooth muscle cells (VSMC) from the A4-A5 branches in SHRSP mesenteric artery.

METHODS

Using the whole-cell Ba2+ current recording of the patch clamp technique.

RESULTS

(1) GTP gamma S, a G-protein agonist, increased whole-cell Ba2+ currents both of SHRSP and Wistar, but SHRSP with a higher ratio of amplitude change than Wistar. In addition, GTP gamma S shifted D infinity to right both in SHRSP and Wistar, but D infinity shifted more in SHRSP than that in Wistar. (2) GDP beta S, a G-protein antagonist, decreased whole-cell Ba2+ currents both of SHRSP and Wistar, but SHRSP with a higher inhibition ratio of amplitude change than Wistar. In addition, GDP beta S shifted F infinity to right and in SHRSP shifted more than control under HP = -80 mV.

CONCLUSIONS

The G-protein mechanism may promote Ca2+ influx and contribute to the increase of peripheral resistance during hypertension.

[The parapharyngeal space tumour of children: reports of 4 cases]

In 1986-1996, four childish patients with parapharyngeal space tumour were treated in our hospital. In the beginning, we ought to define the size and range by CT scanning. The second, we excized it from neck-flank. The patients had a satisfying effect after surgical operation. Meantimes, it's necessary to protect the important vessel and nerve in surgical operation.

[DNA cloning of Ad7 vaccine strain and sequence analysis of its Sma I H fragment]

Human adenoviruses have been a hot topic of study because of their potential utility for gene therapy and development of live viral vectored vaccines. Adenovirus types 4 and 7 have been given orally as vaccines for prevention of acute respiratory infections caused by these serotypes of adenovirus in U.S. army recruits for more than 30 years. Therefore, the advantage of using Ad4 and Ad7 as vectors in the development of oral live recombinant vaccine is obvious. For constructing Ad7 vector, 10.8-100 mu DNA of Ad7 vaccine strain has been cloned. The Sma I H fragment was sequenced using Ad7 DNA as a template and then the fragment was cloned by PCR. For verifying the sequence the fragment was sequenced again. The strategy we used to clone terminal end of adenovirus is reliable and practicable.

[Effect of SNP on KCa of resistance vascular smooth muscle cell membrane in SHRsp]

OBJECTIVE

To investigate the effect of sodium nitroprusside (SNP) on calcium activated potassium channels (KCa) of mesenteric arterial A4-A5 branches resistence vascular smooth muscle cell membrane in Stroke-prone Spontaneously Hypertensive Rats (SHRsp) and its normotensive control WKY rats.

METHODS

Cell-attached patch clamp technique was used.

RESULTS

It was found that SNP could activate the KCa of the resistance vascular smooth muscle in both SHRsp and WKY. Under the same dose of SNP (1 nmol/L), the conductance and channel current amplitude etc. of the activated KCa in SHRsp were smaller than that in WKY rats. Given the same dose of 8-Br-cGMP (10 mumol/L), the cGMP activation of SHRsp KCa was less potentiated than that of WKY, appeared very similar to SNP/NO activation.

CONCLUSIONS

The results suggested the KCa of hypertensive resistance vascular smooth muscle membrane appearing weaker response to relaxing factor EDRF/NO.

Ionic basis of ryanodine's negative chronotropic effect on pacemaker cells isolated from the sinoatrial node

Spontaneous electrical activity and indo 1 fluorescence ratios were recorded simultaneously in cultured pacemaker cells isolated from the rabbit sinoatrial node. Ryanodine (10 microM) reduced the amplitude of action potential-induced intracellular Ca2+ (Ca2+i) transients by 19 +/- 3%, increased the time constant for their decay by 51 +/- 5%, and slowed spontaneous firing by 32 +/- 3%. 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)-acetoxymethyl ester (AM; 25 microM) inhibited the Ca2+i transients and slowed spontaneous firing by 28 +/- 4%. Ryanodine did not alter hyperpolarization-activated or time-independent inward current, but it reduced the sum of L- and T-type Ca2+ currents (ICa,L and ICa,T) in both the presence and absence of BAPTA-AM. In contrast, ICa,L was unchanged by ryanodine. Slow inward current tails, presumed to be Na/Ca exchange current (INa/Ca), were abolished by BAPTA or ryanodine. The results suggest that a decrement of ICa,T, due to reduction of the intracellular Ca2+ concentration or a direct effect of ryanodine on T-type Ca2+ channels, contributes to the negative chronotropic effect. Another possibility, based primarily on theory and results in other preparations, is that a reduction of INa/Ca, as a consequence of the smaller action potential-induced Ca2+i transients, contributes to the effect of ryanodine.

[Diagnosis and treatment of mediastinal tumor by VATS]

Twenty-eight patients with mediastinal tumors underwent thoracoscopic operation, among which 22 received the resection of mediastinal tumor including mediastinal cyst (9), teratoma (5), neurogenic tumor (5), thymoma (1), vagothyrophyma (1), and lipoma (1), and 6 patients received diagnostic biopsy of mediastinal tumor. The preliminary results were promising. The experience of thoracoscopic operation on mediastinal tumor are discussed in this article and VATS is regarded as a new diagnostic and treating method which is superior to conventional thoractomy on some kinds of mediastinal diseases.

[The mutiplication of Sindbis virus and host BHK-21 cell apoptosis]

The process of apoptosis of BHK-21 cells induced by Sindbis virus (SbV) infection is reported here in details. The nuclear DNA cleavage can be first detected at 6 h after SbV infection, followed by the chromatin margination and condensation at 12 h and the DNA ladder can be detected at 24 h after infection. The details of apoptosis body's formation can be revealed by electron microscopy: First, the outer nuclear membrane protrudes where the condensed chromatin accumulates, then the chromatin get into the budding area with the inner nuclear membrane and separate from the nuclear. Progressively, we cloned the gene of SbV nonstructure protein 2 (nsP2) into the eukaryotic expression vector pMAMneo, and it can be expressed transiently. The DNA cleavages, the basic characteristics of apoptosis also can be detected in some cells. Together with the sequence analysis of nsP2 and the other former results, we conclude that the nsP2 may have direct relation with the SbV-induced apoptosis.

[Nuclear reconstitution around purified E. coli DNA in cell-free extracts of Xenopus laevis eggs]

In recent years we have succeeded in inducing various exogenous DNA to assembly typical nuclei in cell-free Xenopus egg extracts. However, it is not clear if prokaryotic chromosomal DNA can also form the nucleus in this eukaryotic system. In our experiment, we used the purified E. coli. chromosomal DNA to reconstitute the nucleus in the nuclear reconstitution extracts and found that typical nuclei can also be assembled around added DNA. We observed the process of nuclear reconstitution by using light microscopy and electronic microscopy. The scanning results of chromatin-like materials and assembled nuclei by microspectrophotometer showed that E. coli, chromosal DNA underwent obvious change from condensation to decondensation during nuclear reconstitution. Incorporation of alpha-32P-dCTP into DNA suggested that the reconstituted nuclei were capable of DNA replication.

[Determination of chlorosilanes by gas chromatography]

Chlorosilanes are the essential raw material of SiC fibre made by "CVD (chemical vapour deposition)" method. The purity of chlorosilane affects the quality of SiC fibre obtained. Therefore, a simple and reliable method for the determination of the constituent of chlorosilane is needed. A gas chromatographic method for quantitative analysis of chlorosilane is described in this paper. The gas chromatographic conditions were as follows: column, 10% diethyl phthalate on 6201 support (60-80 mesh), 3m x 5mm i.d. stainless-steel column; column temp., 60 degrees C; injection temp., 110 degrees C; thermal conductivity detector temp., 140 degrees C carrier gas H2 with flow rate of 60 mL/min. The results show that the method is simple and rapid, and has good precision and reproducibility. The coefficient of variation of the method was less than 1% (n = 6).

Cloning, expression and chromosomal mapping of human lysosomal sialidase and characterization of mutations in sialidosis

Sialidase (neuraminidase, EC 3.2.1.18) catalyses the hydrolysis of terminal sialic acid residues of glyconjugates. Sialidase has been well studied in viruses and bacteria where it destroys the sialic acid-containing receptors at the surface of host cells, and mobilizes bacterial nutrients. In mammals, three types of sialidases, lysosomal, plasma membrane and cytosolic, have been described. For lysosomal sialidase in humans, the primary genetic deficiency results in an autosomal recessive disease, sialidosis, associated with tissue accumulation and urinary excretion of sialylated oligosaccharides and glycolipids. Sialidosis includes two main clinical variants: late-onset, sialidosis type I, characterized by bilateral macular cherry-red spots and myoclonus, and infantile-onset, sialidosis type II, characterized by skeletal dysplasia, mental retardation and hepatosplenomegaly. We report the identification of human lysosomal sialidase cDNA, its cloning, sequencing and expression. Examination of six sialidosis patients revealed three mutations, one frameshift insertion and two missense. We mapped the lysosomal sialidase gene to human chromosome 6 (6p21.3), which is consistent with the previous chromosomal assignment of this gene in proximity to the HLA locus.

[Experience of surgical treatment of patients with N2 lung cancer]

From January 1987 to December 1993, 426 patients with lung cancer were operated in our hospital, among which 159 patients were diagnosed postoperatively to be N2 disease by pathology including 81 central type and 78 peripheral type lung cancer. Radical operations were performed on 135 cases, palliative operations on 24 cases. Follow up study: one-year survival rate was 71.7%, three-year survival rate 29.0% and five-year survival rate 21.7%. The main factors affecting operative results are tumor cell type, the number and location of metastatic lymph nodes and the thoroughness of dissection. Tumor staging, except T4 tumor is not a main factor influencing prognosis. The indications of operation performed on N2 lung cancer and the necessity of extensive nodal exenteration are also discussed in this article. We consider extensive hilar and mediastinal nodal exenteration necessary in order to achieve radical resection and good prognosis.

Fragile site and interstitial telomere repeat sequences at the fusion point of a de novo (Y;13) translocation

We describe a novel fragile site in a rearranged chromosome, associated with the presence of telomeric repeat sequences at the fusion point of a translocation between chromosomes 13 and Y. The case reported in this study shows a de novo (Y;13) translocation, which appears to represent fusion of an apparently intact chromosome Y with a chromosome 13 that has lost only part of its short arm. Ten percent of the cells show a normal karyotype without the (Y;13) translocation. Molecular cytogenetic studies of the derived Y;13 chromosome revealed three hybridization sites of the telomeric probes-one at each end and one at the breakpoint junction. A fragile site is also observed in the intrachromosomic telomeric region. This coincidence suggests that the telomere repeat sequences (TTAGGG)n, when present at an interstitial chromosomal location, can promote the formation of a novel fragile site.

Phosphatidylserine-mediated adhesion of T-cells to endothelial cells

Phosphatidylserine was exposed on the surface of human umbilical endothelial cells (ECV304) a few minutes after adding thrombin in vitro, as monitored by prothrombinase assays with and without annexin V. Jurkat T cells adhered to the thrombin-treated cells. The adhesion was inhibited by annexin V, indicating that it was mediated by exposed phosphatidylserine on the endothelial cells.

[The relationship between prognosis of esophageal squamous carcinoma and Langerhans cell]

The operative tumor specimen of esophageal squamous carcinoma were studied with immunohistochemical (ABC) method S-100 protein staining. Under the light microscopy, we observed the morphology, number and distribution of Langerhan's cells (LC) in different portion of the tumor mass and its relationship with the pathological staging in 167 cases. We observed also the relationship between LC and the postoperative survival period in 127 cases followed for more than 3 years. These results suggested found that positive relation between the number of LC in the cancer nest and in the lymphfollicle with the increasing of TNM classification. The number of LC in the cancer nest significantly increased in state III and IV cases than II cases. On the contrary, the number of LC in the peritumor and interstitial tissue decreased while the TNM classification was increasing. These findings suggested that the survival period was shorter in patients whose LC had increased in the cancer nest, whereas the survival period would be longer in those patients whose LC had increased in the tissue around the tumor mass, in the mucosa near the tumor as well as in the interstitial tissue. These two points might be used as an immunological para-meter for the assessment of the prognosis.

[Lipopolysaccharide (LPS) induced pulmonary inflammatory response and effects of TNF in immunocompromised host (ICH)]

OBJECTIVE

To investigate the pulmonary inflammatory response and TNF-mediated effects in ICH.

METHODS

ICH models of guinea pigs were induced successfully by receiving daily intraperitoneal injections of cyclophosphamide (15mg.kg-1.d-1) plus daily subcutaneous injection of cortisone acetate (100mg.kg-1.d-1) for a total of 7 consecutive days. On the day after the final dose of drugs, guinea pigs were challenged intratracheally with LPS (200 micrograms/animal) and were lavaged before and 1, 3, 5, 8, 24 hours after challenged, respectively.

RESULTS

Five hours after LPS challenged, total counts of bronchoalveolar fluid (BALF) cells and the proportion of PMN increased significantly. Although the counts of both PAM and PMN increased, the proportion of PAM decreased gradually accompanied by increase of the proportion of PMNs. Hematoxylin eosin stained lung sections after challenged with LPS showed an acute intraalveolar inflammatory response. After intra-tracheal injection of LPS, the TNF level in BALF progressively increased. Both the TNF level and PMN count started to increase at 1 hour after LPS challenge, peaked at 5 hours. The TNF level in serum did not increase markedly after intratracheal injection of LPS. In the development of an inflammatory response, a large amount of TNF were released in BALF, the level of TNF in BALF was closely matched the influx of PMN.

CONCLUSIONS

The data suggested that TNF was one of the cytokines which mediated influx of PMNs and inflammation. High level of TNF released in BALF of ICH could induce the lung injury. The systemic inflammatory response of ICH was involving immunosuppressed state after intratracheal injection of LPS, however, strong intraalveolar inflammatory response still occurred, which reflected the phenomenon of "compartmentalization" in inflammatory response.

The use of micromachined surfaces to investigate the cell behavioural factors essential to osseointegration

OBJECTIVE

Although currently available implants can be used to achieve osseointegration under well-defined conditions, a greater understanding of cell behaviour is required to improve the designs and embark on actual tissue engineering.

MATERIALS AND METHODS

We employed micromachined substrata to investigate some of the main behavioural responses of osteoblasts from rat fetal calvaria to surface topography. In particular, confocal laser scanning microscopy (CLSM), differential interference contrast microscopy, time-lapse cinemicrography, immunofluorescence, digital radiography and image analysis were used to investigate cell adhesion, cell shape and cytoskeleton distribution, tissue organization, cell differentiation, and microenvironment.

RESULTS AND CONCLUSIONS

A grooved surface permitted the attachment of more cells than a smooth one. Cell shape and cytoskeleton were strikingly influenced as early as 20 min after cell attachment, when the cytoskeleton begins to align with the topography. Some grooved surfaces appeared to promote osteogenesis in vitro as assessed by the production of bone-like nodules. Moreover, these nodules align with the topography in vitro, and preliminary results indicate that bone-like tissue also aligns with grooves when such surfaces are implanted in vivo.

[Thoracoscopic esophagectomy for esophageal carcinoma: report of 8 patients]

Eight patients with esophageal carcinoma were treated by VATS in our hospital since March 1995. Of the 8 patients, 2 had lower-middle segment esophageal carcinoma and 6 middle segment. The operations performed on seven patients were successful except one that had to be changed to thoractomy as a result of invasion of tumor. Techniques of VATS in treating esophageal carcinoma and indication were discussed.

[Basic study on evaluation of the fundus with monochromatic photography]

By using the monochromatic fundus photographic system we developed, fundus pictures of 93 normal subjects were taken under the illumination of 10 lights with varying wavelengths. A densitometer was used for evaluating these photographic results. Optimal illumination lights were selected respectively for photography of different layers of fundus details. The results showed that the degrees of contrast at the macula, optic nerve fiber layer, physiological cup of papilla, retinal artery and vein, optic nerve head, choroid striae are the highest under the illumination of light with wavelength 478nm, 478nm, 530nm, 570nm, 628nm and 628nm respectively. The visibility of nerve fiber layer in the subjects over 50 years old is the highest under the illumination of light with a wavelength of 530nm. However, the degrees of contrast of all their fundus structural details, especially the macula and nerve fiber layer, are lower than those of subjects under 50 years old photographed with the corresponding lights with optimal wavelengths (P < 0.01).

Biological activity assays of cell-free reassembled nuclei--injecting cell-free reassembled nuclei into unfertilized eggs can induce the eggs to cleave and reconstitute asters, and the injected nuclei undergo cell cycle changes

Nucleus may reassemble spontaneously in cell-free mixture of HeLa metaphase chromosomes, Xenopus egg extracts and ATP-regenerating system, and the nucleus shows some biological activities. It is found that, after being injected into unfertilized mature eggs, the cell-free reassembled nuclei can cause the eggs to cleave and reconstitute asters in their cytoplasm, and the injected nuclei undergo changes in response to cell cycle regulators stored in the eggs, and that reinjecting cytostatic factors (CSF) into the eggs can stabilize the eggs in mitotic phase, cause the nuclei disassembly and chromatin condensation to chromosomes.

[The distribution of SbV nonstructural protein 2 (nsP2) in host cell]

The distribution of SbV nsP2 has been observed by means of immunolabelling electron microscopy. The results showed that SbV nsP2 existed both in the cytoplasm and in the nucleus of host cell. When the cDNA of SbV nsP2 was transfected in host cell, the nsP2 also accumulates in the nucleus.