[Quantitative analysis of vestibulo-ocular reflex and optokinetic reflex electronystagmography in patients with unilateral loss of vestibular function]

OBJECTIVE

To study changes of the vestibular function in the process of vestibular compensation.

METHODS

The electronystagmography recording of spontaneous nystagmus(SN) with tests for vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) were performed in 105 patients with unilateral loss of vestibular function, the results were analysed quantitatively.

RESULTS

(1) Twenty-one patients with courses from 3 days to 6 years presented a SN directed towards the intact side, with an average slow phase velocity (ASPV) of 7.12-12.07 degrees/s. (2) The intensity of VOR nystagmus as a response to the warm-cold water stimulation to the intact ear was lower than that of normal subjects. (3) By 0.167 Hz, 90 degrees sinusional oscillation stimulation, the ASPVs of the patients' VOR nystagmus directed towards the intact and affected sides were lower than that of the normal. A predominance of VOR nystagmus rotation towards the intact side was found in patients with courses < or = 5 years. There was no predominance of VOR nystagmus found in patients with courses > 5 years. (4) There was no significant difference between the optokinetic nystagmus (OKN) intensity of the normal persons and that of patients with lesions outside the cerebellopontine angle and with tumors in cerebellopontine angle which was < 2.5 cm in diameter. The OKN intensity of patients with tumors in cerebellopotine angle with diameters > or = 2.5 cm was lower than that of normal subjects. A predominance of OKN towards the intactside was found in these patients.

CONCLUSION

The vestibular function is in inhibitory and the vestibular system becomes rebalanced due to this inhibition in the process of vestibular compensation.

[Effects of hypoxia and qigong on urine malondialdehyde, superoxide dismutase and circulating endothelial cell in humans during simulated weightlessness]

Changes of lipid hyperoxidation and amount of circulating endothelial cells under simulated weightlessness and factors that may influence these changes were observed in 3 groups of subjects (5 in each group) exposed to 17d - 6 degrees head down bed rest (HDBR), HD-BR+ hypoxia and HDBR + qigong respectively. The results showed: (1) simple HDBR promotes antioxidation activity and attenuates hyperoxidation of lipids, and hypoxia and have some influence on the former but not on the latter; (2) circulating endothelial cells decreased significantly after simple HDBR for 7 d but recovered to normal when HDBR continued for 17 d. Hypoxia showed no influence on this effect while Qigong alleviated it significantly. It suggests that (1)both hypoxia and Qigong have some influence on the promotion of antioxidation activity but have no influence on the production of oxygen free radicals. (2) Qigong shows some antagonistic effect against the attenuation of circulating endothelial cells by HDBR.

Negative regulation of yeast telomerase activity through an interaction with an upstream region of the DNA primer

A number of published studies indicate that telomerase may interact with oligonucleotide primers in a bipartite manner, with the 3'-end of the primer positioned at the catalytic site of the enzyme and a more 5' region of the primer binding to a second or 'anchor' site of the enzyme. We systematically investigated the effects of mutations in the DNA primer on overall binding and polymerization by yeast telomerase. Our studies indicate that there is sequence-specific interaction between telomerase and a substantial region of the DNA primer. Mutations in the 3'-most positions of the primer reduced polymerization, yet had little effect on overall binding affinity. In contrast, mutations around the -20 position reduced binding affinity but had no effect on polymerization. Most strikingly, mutations centered around the -12 position of the DNA primer reduced overall binding affinity but dramatically enhanced primer extension, as well as primer cleavage. This finding suggests that reduced interaction with the -12 region of the DNA primer can facilitate a step in the catalytic region of yeast telomerase that leads to greater polymerization. A tripartite model of interaction between primer and telomerase is proposed to account for the distinct effects of mutations in different regions of the DNA primer.

[Detection of rotavirus RNA using DIG labelled probe prepared by polymerase chain reaction]

The digoxigenin (DIG) labelled cDNA probe of rotavirus was directly prepared by polymerase chain reaction (PCR). The results of cDNA-RNA hybridization showed that the DIG-cDNA probe exhibits rotavirus specificity and can detect as tiny as 10 pg rotavirus RNA. 120 fecal samples of diarrhea from infants and young children were tested by dot-blot hybridization. It was shown that the positive rate of dot-blot hybridization(65.0%) was significantly higher than that of PAGE(49.1%). This study indicated that direct preparation of DIG-labelled rotavirus-cDNA probe by PCR is much faster and simpler than common method of labeling.

[Immunodiagnosis of cysticercosis by simplified western blotting using recombinant fusion protein as antigen]

AIM

To provide simple and useful method for the immunodiagnosis of cysticercosis.

METHODS

Fusion protein of beta-galactosidase-Cysticercus cellulosae cDNA was analysed with simplified Western blot.

RESULTS

The positive rate was 93.5% when detecting 124 cases of human cysticercosis sera with four clones (cC1, cC2, cP1 and cH1) and 100% when detecting 38 cases of porcine cysticercosis sera with three clones (cC1, cC2 and cP1), being higher than those using monoclone fusion protein alone. Moreover, the fusion proteins did not react with other parasitosis sera.

CONCLUSION

Simplified Western blot analysis using recombinant fusion protein as antigen was highly sensitive and specific and easy to be operated.

Computational models for the formation of protocell structures

There have been various attempts to simulate the self-assembly process of lipid aggregates by computers. However, due to the computationally complex nature of the problem, previous simulations were often conducted with unrealistic simplifications of the molecules' morphology, intermolecular interactions, and the environment in which the lipid molecules interact. In this article, we present a new computational model in which each lipid is simulated by a more realistic amphiphilic particle consisting of a hydrophilic head and a long hydrophobic tail. The intermolecular interactions are approximated by a set of simple forces reflecting physical and chemical properties of lipids, for example, hydrophobicity and electrostatic forces, which are believed to be crucial for the formation of various aggregates. With a set of carefully selected parameters, this model is able to simulate successfully the formation of micelles in an aqueous environment and reversed micelle structures in an oil solvent from an initially randomly distributed set of lipidlike particles. This model can be used to study, at the microscopic level, the self-assembly of different protocell structures in the evolutionary process and the impact of environmental conditions on the formation of these structures. It may be further generalized to simulate the formation of other, more complex structures of amphiphilic molecules such as monolayer and bilayer aggregates.

[Human lens epithelial cells culture in vitro]

PURPOSE

To provide a simple and rapid procedure to culture human len epithelial cells in vitro.

METHODS

Specimens of capsule lentils were isolated from lens by microscissors. They were cut into small segments and then directly implanted into basks(culture bottles). The tissue pieces were cultured in a incubation at 37 degrees C with PR1640 until attached cells reached confluence. The len epithelium were passaged by tropism.

RESULTS

Len epithelial cells usually appeared after 4 days in incubation. The cells growed rapidly in a way of attachments.

CONCLUSION

Len epithelial cells were easily cultured with our method. The procedure is simple, rapid and highly successful.

Biotransformation of compactin to pravastatin by Actinomadura sp. 2966

Actinomadura sp. strain 2966 can effectively convert compactin to pravastatin. The degree of conversion observed was 65% to 78% of compactin added and 65% to 88% of compactin taken up, depending on the concentration of compactin and duration of the experiment. Increasing the compactin concentration resulted in a higher final pravastatin concentration especially when compactin was added intermittently. Higher glucose concentrations had no effect on the bioconversion although uptake of compactin was inhibited. The conversion was linear over 16 hours. The system requires no induction and thus appears to be different from previously studied hydroxylases from actinomycetes.

Identification and characterization of a telomerase activity from Schizosaccharomyces pombe

A telomerase-like primer extension activity has been detected in chromatographic fractions derived from Schizosaccharomyces pombe extracts. This primer extension activity acts preferentially on dG-rich oligodeoxynucleotides, is sensitive to RNase A pretreatment and requires all four deoxynucleotides for optimal polymerization. The extension products are also truncated by the inclusion of any one of the four dideoxynucleotides, consistent with the presence of all four bases in the S.pombe telomeric repeats. The intensity distribution of the extension products and the dideoxynucleotide termination pattern suggest that nucleotide addition is template directed, and that telomere-like sequences are added to the primers. In particular, the sequence d(CGGTTA), a variant of the S.pombe telomeric repeat, can be added directly by the in vitro activity. Partially purified S.pombe telomerase sediments as a 35S particle, suggesting that it exists in vivo as part of a large multi-protein complex.

Optical resolution of DL-alanine by using immobilized Aspergillus oryzae cells

Mycelium pellets with diameters of 1-2 mm and containing abundant aminoacylase were obtained by the liquid fermentation of Aspergillus oryzae 3042. By the cross-linking method with reagents of gelatin and formaldehyde, the immobilized A. oryzae cells (IAC) were prepared with much higher activity and reactive properties. The effects of factors on enzymatic activity of IAC were investigated. When substrate concentration was less than 0.15 mol/L, the Michaelis-Menten mechanism was suitable for this reaction.

[Evaluating clinical significance of tumor necrosis factor-alpha and hydroxyproline in blood of patients with active pulmonary tuberculosis]

OBJECTIVE

To evaluate the clinical significance of tumor necrosis factor-alpha (TNF-alpha) and hydroxyproline (HYP) in blood of patients with active pulmonary tuberculosis (APT).

METHOD

Contents of TNF-alpha and HYP in blood of 28 patients with APT and 17 normal subjects were determined with enzyme-linked immunosorbent assay and ultraviolet spectrophotometer respectively.

RESULT

It was found that the concentrations of TNF-alpha and HYP in patients with APT before antituberculosis treatment were obviously higher than those of the normal subjects (192.85 +/- 37.14 ng/L vs 89.36 +/- 23.18 ng/L and 4.96 +/- 1.13 mg/L vs 1.64 +/- 0.33 mg/L respectively, all P < 0.001) and those who received 3- month anti-tuberculosis treatment (192.65 +/- 37.14 ng/L vs 112.50 +/- 44.93 ng/L and 4.96 +/- 1.13 mg/L vs 2.17 +/- 0.39 mg/L respectively, all P < 0.001). TNF-alpha level was significantly correlated with HYP (r = 0.5132, P < 0.001).

CONCLUSION

The results indicate that TNF-alpha might play an important role in inducing pulmonary tissue damage of APT, and the lowering of HYP content in blood might indicate that pulmonary tuberculosis is recovering from active stage.

Arrest of the cell cycle by the tumour-suppressor BRCA1 requires the CDK-inhibitor p21WAF1/CiP1

Much of the predisposition to hereditary breast and ovarian cancer has been attributed to inherited defects in the BRCA1 tumour-suppressor gene. The nuclear protein BRCA1 has the properties of a transcription factor, and can interact with the recombination and repair protein RAD51. Young women with germline alterations in BRCA1 develop breast cancer at rates 100-fold higher than the general population, and BRCA1-null mice die before day 8 of development. However, the mechanisms of BRCA1-mediated growth regulation and tumour suppression remain unknown. Here we show that BRCA1 transactivates expression of the cyclin-dependent kinase inhibitor p21WAF1/CIP1 in a p53-independent manner, and that BRCA1 inhibits cell-cycle progression into the S-phase following its transfection into human cancer cells. BRCA1 does not inhibit S-phase progression in p21-/- cells, unlike p21+/+ cells, and tumour-associated, transactivation-deficient mutants of BRCA1 are defective in both transactivation of p21 and cell-cycle inhibition. These data suggest that one mechanism by which BRCA1 contributes to cell-cycle arrest and growth suppression is through the induction of p21.

Immunohistochemical localization of lysosomal cathepsin D in schwannomas

The immunohistochemical localization of cathepsin D (CD) was demonstrated for the first time in 54 schwannomas (32 intra- and 22 extracranial; 47 benign and 7 malignant) and 5 normal nerve fibers. Granular or vesicular CD-reactive structures were observed in all normal Schwann cells. All tumors contained CD-reactive tumor cells, although the population of CD-reactive tumor cells, the density, intracellular localization, and morphology of CD-reactive structures, and the intensity of CD immunoreactivity varied from case to case, portion to portion, and cell to cell, differing variously from those in normal Schwann cells. The variations were greater in malignant than in benign schwannomas. In mildly degenerate tumor cells, CD immunoreactivity was increased, possibly in response to the increased intracellular degenerate proteins, suggesting that the mechanism of induction of lysosomal proteases preserved in normal cells is not affected by the process of neoplastic transformation. In lesions of severe degeneration or necrosis, CD immunoreactivity was lost in most tumor cells but was strong in macrophages invading the lesions and perivascular regions. CD immunoreactivity was observed at various intensities in tumor cells in the Antoni type A area but not in most tumor cells in the Antoni type B area, suggesting that Antoni type B lesions show degenerative changes. The presence of CD-reactive tumor cells in all tumors examined and strong CD immunoreactivity observed at the invasion front of tumors in some cases of benign or malignant schwannoma suggests the possible role of CD in tumor invasion in some cases.

Cyclopia in one of discordant twins: a case report

Cyclopia is an uncommon congenital anomaly resulting from arrest of the development of the anterior end of the neural plate. It is always associated with abnormalities of the brain. Cyclopia has never been reported in one twin only. In this report, we describe a case of cyclopia in a female infant with normal karyotype who was one of discordant twins. The infant died perinatally. The parents were healthy and not sanguineously related. Prenatal imaging studies revealed cyclopia, holoprosencephaly and hypognathia. Postmortem examinations revealed one orbit, one eyeball and absence of the nose. The central nervous system included rudimentary cerebral hemispheres with fusion of the two lateral ventricles and the third ventricle forming a single large cavity. The superior aspect of each cerebral hemisphere consisted of only a transparent membrane. The olfactory bulb nad tract was absent. The optic nerves were not identified.

[Analysis of chromosome karyotype of Lycium chinense Mill]

The chromosome karyotypes of wild Lycium chinese and its cultivated breeds for vegetable have been studied. The Chromosome 12 of both has a satellite. The former, with 24 chromosomes and 1B karyotype, is a diploid and its karyotype formula is 2n = 2x = 24 = 18m + 6sm. The chromosome number of the latter is 48. As a tetrploid, it has 2B karyotype and a karyotype formula 2n = 4x = 48 = 36m + 12sm.

Cloning, human chromosomal assignment, and adipose and hepatic expression of the CL-6/INSIG1 gene

Rat CL-6 is the most highly insulin-induced gene in a liver cell line and is expressed in proliferating liver during regeneration and development. CL-6 is now denoted INSIG1 (insulin-induced gene 1). Human INSIG1 was isolated and found to be 80% identical to the rat gene within the translated region. It was located on human chromosome 7 within band q36. The human INSIG1 promoter conferred a high level of expression in both liver and fibroblast cell lines. INSIG1 expression was upregulated at the transcriptional level in rat regenerating liver and induced in a model of murine adipocyte differentiation, suggesting that INSIG1 may play a role in growth and differentiation of tissues involved in metabolic control.

HRS/SRp40-mediated inclusion of the fibronectin EIIIB exon, a possible cause of increased EIIIB expression in proliferating liver

Serine-arginine (SR)-rich proteins are believed to be important in mediating alternative pre-mRNA splicing. HRS/SRp40 expression is elevated in liver cell proliferation during development, regeneration, and oncogenesis. We tested whether HRS expression correlates with the appearance of alternatively spliced fibronectin transcripts during liver growth. HRS was highly expressed during the proliferative phase of liver development, correlating with expression of the fibronectin EIIIB alternative exon. In regenerating liver, HRS protein was induced in a time course consistent with the observed increase in fibronectin transcripts containing the EIIIB exon, particularly in nonparenchymal liver cells. Furthermore, in an in vivo assay, HRS, and not other SR proteins, directly mediated EIIIB exon inclusion in the fibronectin transcript. This alternative splicing was dependent on a purine-rich region within the EIIIB exon to which HRS specifically bound. We have established that HRS has the potential to contribute to the regulation of fibronectin pre-mRNA splicing during liver growth. Changes in fibronectin forms may be important in modifying liver architecture during the proliferative response, thus providing a potential mechanism by which SR proteins may participate in cellular growth control.

Posttransplant lymphoproliferative disorders: a fine-needle aspiration biopsy study

Fine-needle aspiration biopsy (FNAB) has been used with high sensitivity and specificity in the diagnosis of both Hodgkin's and non-Hodgkin's lymphoma. However, studies of FNAB of posttransplant lymphoproliferative disorders (PTLDs) are rare. The clinical course of 593 allograft recipients (cardiac, 288; renal, 250; lung, 50; and heart/lung, 5) was reviewed. Twenty-six patients developed PTLD with an overall incidence of 4.4%. Of these patients, 12 underwent FNAB. Their age ranged from 33-67 yr (mean, 55 yr). The interval between transplantation and FNAB ranged between 2-14 mo (average, 8.4 mo). The lungs were the most common site aspirated (7 cases), followed by lymph nodes (3 cases) and other extranodal sites (2 cases, liver and paraspinal mass). The cytologic features of these aspirates could be classified into two categories: a polymorphous smear composed of a spectrum of mature and immature lymphocytes with scattered plasma cells and histiocytes; and a monotonous population of large lymphoid cells consistent with malignant lymphoma, large-cell type. Surgical biopsies were available in 10 (83.3%) cases and confirmed the FNAB diagnosis. In summary, FNAB appears to be a highly sensitive and specific diagnostic tool in patients with PTLD.

[Effects of the double chamber intra-aortic balloon pumping on the renal circulation]

The effects of the double chamber intra-aortic balloon (DIAB) and the single chamber intra-aortic balloon (SIAB) on the hemodynamic parameters in the kidney were studied. No negative effect of both cases was observed. Before and after removing the renal nerve system, the DIAB was used and the results had been compared. The pulse produced by pumping activized the renal nerve system and reduced the renal vascular resistance. Therefore the reduction of the renal vascular resistance is an important reason for increasing the renal blood flow during intra-aortic balloon pumping.

Localization of BRCA1 and a splice variant identifies the nuclear localization signal

Inherited mutations in BRCA1 confer susceptibility to breast and ovarian neoplasms. However, the function of BRCA1 and the role of BRCA1 in noninherited cancer remain unknown. Characterization of alternately spliced forms of BRCA1 may identify functional regions; thus, we constructed expression vectors of BRCA1 and a splice variant lacking exon 11, designated BRCA1 delta 672-4095. Immunofluorescence studies indicate nuclear localization of BRCA1 but cytoplasmic localization of BRCA1 delta 672-4095. Two putative nuclear localization signals (designated NLS1 and NLS2) were identified in exon 11; immunofluorescence studies indicate that only NLS1 is required for nuclear localization. RNA analysis indicates the expression of multiple, tissue-specific forms of BRCA1 RNAs; protein analysis with multiple antibodies suggests that at least three BRCA1 isoforms are expressed, including those lacking exon 11. The results suggest that BRCA1 is a nuclear protein and raise the possibility that splicing is one form of regulation of BRCA1 function by alteration of the subcellular localization of expressed proteins.

Early versus deferred zidovudine monotherapy: impact on AIDS-free time and survival in the multicenter AIDS cohort study

The objective of this study was to compare the time to AIDS and to death between men receiving zidovudine therapy before or not before the diagnosis of AIDS. For the time to AIDS comparison, 821 men receiving zidovudine therapy before the diagnosis of AIDS were pair matched with men who did not receive zidovudine therapy until after diagnosis on their CD4 cell count (+/- 75 cells/mm3), haemoglobin level (+/- 0.75 g/dl), number of clinical symptoms and study visit at the time of initiation of zidovudine therapy and were monitored for a median of 2.08 years. For the time to death comparison, 186 men who received zidovudine therapy prior to AIDS diagnosis were pair matched on the same variables to men who received zidovudine therapy only after the AIDS diagnosis, and were monitored for a median of 2.88 years. Only men with < 350 CD4 cells/mm3 who received zidovudine therapy prior to AIDS diagnosis remained AIDS free significantly longer than their pair match who did not (P < 0.0001). The median extension of time to AIDS was 0.61 years for men with < 200 CD4 cells/mm3 and 1.13 years for men with 200-349 CD4 cells/mm3. Cox regression analysis showed a significantly increased time to AIDS for the men with < 350 CD4 cells/mm3, both before and after adjustment for the use of prophylactic drugs against Pneumocystis carinii pneumonia. No difference was seen in the time to death between men receiving zidovudine therapy before or only after AIDS diagnosis. Zidovudine treatment of asymptomatic HIV-1-infected men provides significant benefit to men with < 350 CD4 cells/mm3 by extending AIDS-free time, but does not extend survival. The analytical technique used is applicable to other observational studies of treatment.

Detection of minimal residual disease in leukemia using polymerase chain reaction and restriction analysis

OBJECTIVE

To investigate the relationship between the clinical outcome of childhood acute lymphoblastic leukemia and the status of minimal residual disease after termination of therapy.

METHODS

A total of 18 children with acute lymphoblastic leukemia were studied. Eleven cases were treated with chemotherapy, the other 7 with autologous peripheral blood stem cell transplantation (ABSCT) or autologous bone marrow transplantation (ABMT). The outcome of the 18 patients was obtained by clinical follow-up. Minimal residual disease was detected by means of the polymerase chain reaction (PCR) and restriction analysis.

RESULTS

Minimal residual disease was detected in 9 patients after completion of therapy. Three out of the 9 patients relapsed within 3 to 6 months. Among the other 9 patients with no detectable minimal residual disease, no one relapsed.

CONCLUSIONS

PCR detection of minimal residual disease after termination of therapy can identify patients at risk for relapse in future. Minimal residual disease that cannot be detected after termination of therapy may be one of the important factors for long-term disease-free survival.

Mechanism of anti-beta-adrenoceptor antibody mediated myocardial damage in dilated cardiomyopathy

Antibodies against beta(1)-adrenoceptor can be detected in serum of patients with dilated cardiomyopathy (DCM), which have beta-agonist-like activity, and induce a positive chronotropic effect on cardiac myocytes by its persistence at full strength. Effects of the antibodies against beta-adrenoceptor from sera of patients with DCM on myocardial cytotoxicity and cytoplasmic free Ca(2+)-concentration ([Ca2+]i) were observed in the cultured single layer SD rat ventricular cells by using the cytotoxicity assay and fluorescent Ca(2+)-indicator fura-2/AM. The positive sera of the anti-beta-adrenoceptor antibodies from patients with DCM markedly enhanced myocardial [Ca2+]i. Betaloc, a beta(1)-receptor blocker, might inhibit the increase of the antibody-mediated myocardial [Ca2+]i, and the sera from healthy donors had no effect on myocardial [Ca2+]i. Our results suggest that the anti-beta-adrenoceptor antibody might increase myocardial [Ca2+]i and result in myocardial damage. The antibodies might activate receptor-gating Ca(2+)-channel, thereby causing myocardial [Ca2+]i rise and calcium overload. Early use of betaloc is recommended in the treatment of dilated cardiomyopathy.

Field trials of combined use of two species of mermithid nematodes to control Anopheles and Culex breeding in China

The field tests of combined use of Romanomermis yunanensis 2000-3000 larvae per sq m and Romanomermis sp 1000-2000 larvae per sq m in rice fields. Ponds and streams in four cities of China, resulted in 60.8-95.5% parasitism in Culex tritaeniorhynchus, Cx. quinquefasciatus, Anopheles sinensis and An. anthropophagus. This successful use of two species of Romanomermis together not only curb mosquito nuisance it also controls the major vectors of malaria, filariasis and encephalitis B in China.