[Survey on the fumonisins intake and the urinary Sa/So ratio of people suffered from a high incidence of esophageal cancer]

To explore the correlation between fumonisins and human esophageal cancer (HEC), the estimated fumonisin intake and the urinary sphinganine/sphingosine (Sa/So) ratio were investigated in the population with a high HEC incidence in the suburb of Hebi city, Henan province. Fumonisins were detected from 95 percent of corn samples in the endemic area, and the concentration of total fumonisins (fumonisin B1, B2 and B3) was in the range from 7.2 to 726.8 micrograms/kg. The estimated daily intake of fumonisins was in the range from 0 to 4.84 micrograms/(kg.d) in males, while from 0 to 4.04 micrograms/(kg.d) in females. Compared with the population in a low HEC incidence area, Suixian county, Henan province, the urinary Sa/So ratio of males in the endemic area was statistically significant higher, although no difference was observed in females. The results indicated that fumonisin might be one of the risk factors for the occurrence of HEC.

[Rapid detection of enterohemorrhagic Escherichia coli in food with multiplex PCR assay]

Rapid detection of enterohemorrhagic Escherichia coli (EHEC) in food was achieved by using multiplex PCR assay. The assay was designed to amplify the 1109, 302 and 228 bp regions of corresponding virulence genes eaeA, hlyAB, slt1 and/or slt2, by using specific primers for each one reaction. In 60 EHEC and other strains, the above three virulence gene sequences were co-amplified from DNA isolated from 12 EHEC O157:H7 strains, 1 O26:H11 strain and 1 O111:H8 strain; eaeA sequence was amplified from DNA isolated from 2 EAEC strains; slt1/2 sequence was amplified from DNA isolated from 1 VTEC strain. No specific amplification product was produced from other 43 non-EHEC strains. For the detection of EHEC in food, results could be obtained within 8 hrs, and the sensitivity of assay was less than or equal to 1.6 cfu/g(ml) of food. The method was applied to 126 food samples, and EHEC was detected in 3 samples.

Migration and differentiation of Nkx-2.2+ oligodendrocyte progenitors in embryonic chicken retina

During early neural development, the Nkx-2.2 homeobox gene is initially induced in the ventral ventricular zone of the central nervous system (CNS). At later stages, Nkx-2.2+ cells migrate away into the surrounding regions and co-express several oligodendrocyte marker genes. Here we report that Nkx-2.2+ cells also migrate into the avian retina from the optic nerve. These Nkx-2.2+ cells are specifically labeled by the early oligodendrocyte markers PDGFR alpha, O4 and GalC, but not the microglial marker QH1 or neuron-specific marker MAP-2. These observations provide further evidence that Nkx-2.2 is selectively expressed in migratory oligodendrocyte progenitor cells and that retina oligodendrocytes originate from the ventral diencephalon.

Control of oligodendrocyte differentiation by the Nkx2.2 homeodomain transcription factor

Oligodendrocytes are derived from glial precursors that arise from the ventral neural tube early in development. In the developing chicken CNS, oligodendrocyte progenitors selectively express Nkx2.2 homeodomain transcription factor, raising the possibility that Nkx2.2 may directly regulate oligogliogenesis. In this study, we have examined Nkx2.2 expression in rodent glial precursors and studied the effect of a loss of Nkx2.2 on oligodendrocyte and astrocyte differentiation. We show that Nkx2.2 is also expressed in mammalian oligodendrocyte progenitors and that the differentiation of MBP-positive and PLP-DM20-positive oligodendrocytes is dramatically retarded in Nkx2.2-null mutants along the entire rostrocaudal axis. In contrast, no effect is seen on astrocytic differentiation. Interestingly, absence of Nkx2.2 expression leads to a ventral expansion of the Olig1/Olig2 expression in neuroepithelial cells into the Nkx2.2 domain and a consequent increase in the production of Olig1/Olig2-positive and platelet-derived growth factor receptor α-positive oligodendrocyte progenitors. These results strongly suggest that Nkx2.2 regulates the differentiation and/or maturation, but not the initial specification, of oligodendrocyte progenitors. Consistent with this suggestion, overproduction of Nkx2.2 protein in fibroblast cells can induce gene expression from the proteolipid protein promoter.

Mice lacking the Nkx6.2 (Gtx) homeodomain transcription factor develop and reproduce normally

The Nkx homeobox genes are expressed in a variety of developing tissues and have been implicated in controlling tissue patterning and cell differentiation. Expression of Nkx6.2 (Gtx) was previously observed in the embryonic neural tube, testis, and differentiating oligodendrocytes. To investigate the role of Nkx6.2 in the control of cell specification and differentiation, we generated mice with null mutations in Nkx6.2 using the standard gene targeting approach. Null mutant mice were viable and fertile without apparent histological and immunohistochemical changes in the central nervous systems and testis. The absence of detectable phenotypes suggests a redundant function of Nkx6.2 in mouse development.

[A clinical study on the combination of gemcitabine and cisplatin in the treatment of advanced non-small cell lung cancer]

BACKGROUND

To evaluate the efficacy and toxicity of the combination of gemcitabine and cisplatin in the treatment of patients with advanced non-small cell lung cancer (NSCLC).

METHODS

Forty-three patients with locally advanced (stage IIIB) or metastatic (stage IV) NSCLC were enrolled into the study. The patients received gemcitabine 1 000 mg/m² on day 1,8 and 15, and cisplatin 30 mg/m² on day 1-3 of the 28-day cycle; or gemcitabine 1 200 mg/m² on day 1 and 8, cisplatin 30 mg/m² on day 1-3, administered in 21-day cycle.

RESULTS

An objective response was obtained in 48.8% of patients (one complete and 20 partial responses), whereas 13 patients had stable disease and 9 patients were progressive. The response rate was 62.5% in patients with no prior chemotherapy, and the response rate of 31.6% was achieved in patients who had been given prior treatment. Significant difference existed between the two groups (P<0.05). The main toxicities were leukopenia and thrombocytopenia.

CONCLUSIONS

The combination of gemcitabine and cisplatin is a feasible, well-tolerated, and active scheme in the treatment of advanced NSCLC.

[The effects of quercetin and isorhamnetin on oxidative modification of VLDL induced by Cu2+]

OBJECTIVE

To observe the effects of quercetin(Que) and isorhamnetin (Iso) on the oxidative modification of very low density lipoprotein (VLDL).

METHODS

Human VLDL was prepared by one-step ultracentrifuge and oxidized by Cu2+ in vitro; Que and Iso in different concentrations were added to VLDL before incubation with Cu2+. The MDA, vitamin E contents and the activity of superoxide dismutase(SOD) in ox-VLDL were determined.

RESULTS

Compared with ox-VLDL group, Que and Iso decreased MDA production in a dependent concentration-manner, Que and Iso also elevated Vit E level and SOD activity markedly.

CONCLUSION

This experiment indicates that Que and Iso have similar inhibitory effects on the oxidative modification of VLDL.

Leukocyte-specific adaptor protein Grap2 interacts with hematopoietic progenitor kinase 1 (HPK1) to activate JNK signaling pathway in T lymphocytes

Immune cell-specific adaptor proteins create various combinations of multiprotein complexes and integrate signals from cell surface receptors to the nucleus, modulating the specificity and selectivity of intracellular signal transduction. Grap2 is a newly identified adaptor protein specifically expressed in lymphoid tissues. This protein shares 40--50% sequence homology in the SH3 and the SH2 domain with Grb2 and Grap. However, the Grap2 protein has a unique 120-amino acid glutamine- and proline-rich domain between the SH2 and C-terminal SH3 domains. The expression of Grap2 is highly restricted to lymphoid organs and T lymphocytes. In order to understand the role of this specific adaptor protein in immune cell signaling and activation, we searched for the Grap2 interacting protein in T lymphocytes. We found that Grap2 interacted with the hematopoietic progenitor kinase 1 (HPK1) in vitro and in Jurkat T cells. The interaction was mediated by the carboxyl-terminal SH3 domain of Grap2 with the second proline-rich motif of HPK1. Coexpression of Grap2 with HPK1 not only increased the kinase activity of HPK1 in the cell, but also had an additive effect on HPK1 mediated JNK activation. Furthermore, over expression of Grap2 and HPK1 induced significant transcriptional activation of c-Jun in the JNK signaling pathway and IL-2 gene reporter activity in stimulated Jurkat T cells. Therefore, our data suggest that the hematopoietic specific proteins Grap2 and HPK1 form a signaling complex to mediate the c-Jun NH(2)-terminal kinase (JNK) signaling pathway in T cells.

Elevated superoxide production by active H-ras enhances human lung WI-38VA-13 cell proliferation, migration and resistance to TNF-alpha

Accumulating evidence has suggested that cellular production of superoxide acts as an intracellular messenger to regulate gene expression and modulate cellular activities. In this report, we set out to investigate the role of active H-ras-mediated superoxide production on tumor cell malignancy in a SV-40 transformed human lung WI-38 VA-13 cell line. Stable transfection and expression of constitutively active mutant V12-H-ras (V12-H-ras) dramatically increased intracellular production of superoxide. The expression of V12-H-ras significantly enhanced cell proliferation, migration and resistance to TNF-alpha treatment compared to that of parental and vector control cells, while expression of wild type H-ras (WT-H-ras) only had modest effects. Upon scavenging by superoxide dismutase and other molecules that decrease the intracellular level of active H-ras mediated superoxide production, cell proliferation, migration and resistance to TNF-alpha were significantly reduced. Furthermore, we demonstrated that the activation of membrane NADPH oxidase activity by expression of active H-ras contributed to the intracellular superoxide production. The causal relationship between membrane superoxide production and increased cell proliferation, migration, and resistance to TNF-alpha by the expression of active H-ras, has provided direct evidence to demonstrate that superoxide acts as an intracellular messenger to cascade ras oncogenic signal relay and to modulate tumor malignant activity.

Determination of sphinganine, sphingosine and Sa/So ratio in urine of humans exposed to dietary fumonisin B1

Fumonisin B1 (FB1) is an inhibitor of sphinganine N-acyltransferase and the increase in the sphinganine/ sphingosine (Sa/So) ratio in urine or serum has been proposed as a biomarker to evaluate exposure to fumonisins. The objectives of this study were to (1) develop a liquid chromatographic method sufficiently sensitive to determine the low concentration of free Sa in male human urine, and (2) analyse So and Sa in human urine and monitor the Sa/So ratio in urine of humans exposed to FB1 in corn diets over 1 month. The liquid chromatographic method involved isolation from human urine of exfoliated cells followed by an extraction of free sphingoid bases and their separation and quantification by high performance liquid chromatography. The detection limits for So and Sa were 0.15 ng/ml in female urine (2 ml used) and 0.005 ng/ ml in male urine (60 ml used). Twenty-eight healthy adult volunteers consumed for 1 month a normal diet containing their homegrown corn potentially contaminated with FB1. Immediately preceding the start of the test, morning urine samples for the determination of So and Sa were collected from each person, and the corn samples used in cooking were obtained from each family for the determination of FB1. At the end of the test period, morning-urine samples were collected from each person and analysed again. The daily FB1 intakes were estimated and used to assess the relationship between them and the urinary Sa/So ratios in humans exposed to dietary FB1 over 1 month. All the homegrown corn samples contained FB1 ranging from 0.08 to 41.1 mg/kg, and the estimated daily FB1 intakes ranged from 0.4 to 740 microg/kg b.w./day. The 1-month monitoring results suggest that sphingolipid metabolism of humans could be affected by FB1 intake, the urinary Sa/So ratio may be useful for evaluating FB1 exposure when the contamination of FB1 is high, and that males are more sensitive to FB1 disruption of sphingolipid metabolism than females.

Selective expression of Nkx-2.2 transcription factor in chicken oligodendrocyte progenitors and implications for the embryonic origin of oligodendrocytes

Recent studies have demonstrated that oligodendrocytes originate from the ventral region of the developing spinal cord. However, the precise neuroepithelial origin of oligodendrocytes remains controversial, and the transcriptional control of oligodendrocyte lineage specification is largely unknown. Here we present evidence that oligodendrocytes in the embryonic chicken spinal cord can be generated from neuroepithelial cells that express the Nkx-2.2 homeodomain transcription factor. Nkx-2.2 expression is initially confined to a narrow stripe of neuroepithelium flanking the floor plate. Later, Nkx-2.2+ cells migrate ventrally and dorsolaterally into the surrounding gray and white matter regions where they undergo rapid proliferation. Double labeling experiments revealed that Nkx-2.2+ cells coexpress markers specific for oligodendrocyte progenitors, e.g., PDGFRalpha+, O4, and R-mAb antigens. In the brain, the Nkx-2.2 cells are also highly migratory and can generate oligodendrocytes. The persistent expression of the Nkx-2.2 homeodomain transcription factor in the oligodendrocyte lineage suggests its important role in the control of oligodendrocyte development.

[Laparoscopic gastric resection]

OBJECTIVE

To modify laparoscopic surgery for gastric diseases.

METHODS

From December 1992 to January 1999, 61 gastric laparoscopic operations were performed in our hospital. The age of the patients ranged from 29 to 78 years (mean 57.4). 17 patients had Billroth II gastrectomy, 1 Billroth I gastrectomy, 2 proximal subtotal gastrectomy, 5 highly selective vagotomy, 3 gastrostomy, and 33 resection of gastric submucosal benign tumor. 54 patients (88.5%) underwent complete laparoscopy, and 7 (11.5%) an assisted one

RESULTS

The mean operative time was (164.2 +/- 93.5) min, the mean estimated blood loss was (218.3 +/- 166.6) ml, and the mean hospital stay was (6.8 +/- 2.1) days. Flatus was present within 48 hours in 86% of the patients. Two patients had laparoscopic surgery for early gastric cancer, and were followed up for more than 55 months. Postoperative complication were noted in 2 patients, who were cured by reoperation and endoscopy therapy respectively. Only 4 patients required postoperative analgesics.

CONCLUSION

Although specific indications need to be defined, laparoscopic surgery is feasible. But long-term follow-up should be made to evaluate its efficacy in treatment of gastric cancer.

GCIP, a novel human grap2 and cyclin D interacting protein, regulates E2F-mediated transcriptional activity

Regulation of mammalian cell growth and proliferation is governed through receptor-mediated signaling networks that ultimately converge on the cell cycle machinery. Adaptor proteins play essential roles in the formation of intracellular signaling complexes, relaying extracellular signals from the plasma membrane to the nucleus of a cell. The leukocyte-specific adaptor protein Grap2 is a central linker protein in immune cell signaling and activation. Using Grap2 as bait protein, we identified a novel human protein, GCIP (Grap2 cyclin-D interacting protein). We found that GCIP bound to Grap2 in both yeast two-hybrid assays and in mammalian cells through binding to the COOH-terminal unique domain and SH3 domain (designated QC domain) of Grap2. GCIP also associated with cyclin D both in vitro and in vivo. The expression of GCIP was found in all human tissues examined with the highest level of expression in the heart, muscle, peripheral blood leukocytes, and brain. Furthermore, phosphorylation of retinoblastoma protein by cyclin D-dependent protein kinase was reduced and E2F1-mediated transcription activity was inhibited in cells transfected with GCIP. High level expression of GCIP in terminally differentiated tissues and the inhibition of E2F1 transcription activation suggest that GCIP could play an important role in controlling cell differentiation and proliferation.

[A study on the relationship between the expression of Bax gene products and prognosis in patients with human non-small cell lung cancer]

BACKGROUND

To explore the relationship between the expression of Bax gene and oncogenesis , development and prognosis of lung cancer.

METHODS

The expression level of Bax gene products was detected in 124 human non-small cell lung cancer by immunohistochemistry labelled-streptavidin-biotin methods.

RESULTS

The expressional level of Bax products in lung cancer tissues (53. 76 %) was significantly lower than that in the normal tissues adjacent to lung cancer (75. 51 %) and normal lung tissues (74. 97 %) ( P < 0. 01) . The expressional level of Bax products was closely related with P-TNM stage , the size of primary tumor and lymph node metastasis ( P < 0. 01 or P < 0. 05) ; but not to histological classification , cell differentiation and site of the cancer , and age , sex of the patients and smoking or not ( P > 0. 05) . The five-year survival rate in patients with high Bax expression was significantly higher than that in patients with low Bax expression ( P < 0. 01) .

CONCLUSIONS

Abnormal expression of Bax gene may play an important role in the oncogenesis , development and prognosis of lung cancer. Bax gene may be involved in the oncogenesis , development and metastasis of lung cancer.

[A multicenter randomized phase II trial of domestic product of rhG-CSF(Rui Xue Xin) in preventing leukopenia caused by chemotherapy in patients with lung cancer]

BACKGROUND

To evaluate the effect and toxicity of the domestic product of rhG-CSF (Rui Xue Xin) in preventing leukopenia caused by chemotherapy in patients with lung cancer.

METHODS

67 patients in multicenter were randomly devided into AB group and BA group. The first cycle was a trial cycle (chemotherapy plus injection of Rui Xue Xin) , and the second cycle was a control cycle (chemotherapy alone) in AB group. On the contrast , the first cycle was a control cycle , and the second cycle was a trial cycle in BA group. The changes of white blood cell (WBC) and absolute neutrophil counts (ANC) , and the side effect of Rui Xue Xin were observed and compared between the trial cycle and control cycle.

RESULTS

Of the 67 patients , 6 cases were out of the trial because of patient compliance , and the another one case due to fever , and the other 61 cases could be used to analyze and to evaluate the effects and toxicity of Rui Xue Xin. The duration of leukopenia and neutropenia in cycle A was significantly shorter than that in cycle B ( P < 0. 01) . The nadirs of WBC and ANC following chemotherapy were remarkably higher in cycle A than those in cycle B ( P < 0. 01) . The incidence of chemotherapy delay due to WBC < 4. 0 *109 /L on the 21st day after chemotherapy in cycle A was also significantly lower than that in cycle B ( P < 0. 01) . The total rate of side effects of Rui Xue Xin was 26. 2 % , including pain and scleroma on the injection sites , weakness , fever. But , all of them were mild and didn't need to give any treatment.

CONCLUSIONS

The results demonstrate that Rui Xue Xin is able to reduce the degree of leukopenia and neutropenia , and to shorten the duration of leukopenia and neutropenia caused by chemotherapy in patients with lung cancer. The toxicity is also slight.

Evidence for the differential regulation of Nkx-6.1 expression in the ventral spinal cord and foregut by Shh-dependent and -independent mechanisms

The Nkx-6.1 homeodomain transcription factor was previously shown to be expressed in ventral neural progenitor cells and subsequently subsets of unidentified motor neurons during early neural development. In this study, we identify a specific subpopulation of motor neurons, the median half of the lateral motor neuron column (LMCm), that retain a strong expression of Nkx-6.1. In addition, we report novel patterns of Nkx-6.1 expression in several mesenchymal tissues surrounding Sonic hedgehog (Shh)-expressing cells, including ventral spinal meninges, esophageal mesenchyme, and dorsal tracheal mesenchyme. Whereas Shh signaling is required for Nkx-6.1 expression in the ventral neural tube and spinal meninges, an Shh-independent pathway appears to operate in regulating Nkx-6.1 expression in the foregut. The persistent and robust expression of Nkx-6.1 in motor neurons and mesenchymal cells suggests an important role for Nkx-6.1 in controlling cell fate specification and differentiation. genesis 27:6-11, 2000.

Thermal physiological consideration of precooling procedures in manned space craft

OBJECTIVE

To explore a space craft precooling temperature at which excessive thermal stress on the crew member could be prevented or reduced in an overheated launch or reentry module.

METHOD

Five young male volunteers wearing a space suit participated in 25 tests at sea level. The space suit was either ventilated in a volume air flow rate of 100 L/min (STPD) with ambient air at temperatures (Ta) of 15 degrees C, 10 degrees C, and 5 degrees C, respectively, or not ventilated. Rectal (Tr), mean skin (Tsk) and mean body (Tb) temperatures were measured.

RESULT

At Ta 15 degrees C, Tr decreased without significance (from 37.0 +/- 0.2C to 36.7 +/- 0.3 degrees C) in 120-min tests, whereas mean Tsk and mean Tb decreased significantly, and subjects had local cold strain whether the space suit was ventilated or not; while at Ta 10 degrees C, Tr decreased from 37.0 +/- 0.3 degrees C to 36.3 +/- 0.3 degrees C (P < 0.05), subjects had a whole body cold strain, and both mean Tsk and Tb dropped continuously and significantly.

CONCLUSION

Ambient temperature 15 degrees C, at which the thermal comfort states of crew was not significantly degraded, was acceptable after precooling in a space craft.

Effects of XW630 on bone formation in ovariectomized rats and in human osteoblast-like cells

OBJECTIVE

To study the effects of XW630 on bone formation in overiectomized (OVX) rats and in human osteoblast-like cell line TE85.

METHOD

Bone histomorphometric analysis was performed with undecalcified bone sections and tetracycline intraperitoneally labeling.

RESULTS

Compared with that of OVX rats, the static data of trabecular bone volume (TBV)/total tissue volume (TTV), TBV/sponge bone volume (SBV) and mean trabecular plate density (MTPD) were enhanced while mean trabecular plate spacing (MTPS) decreased after treated with XW630 for 13w. The dynamic data of single-labeled surface [Sfract(s)], double-labeled surface [Sfract(d)], Sfract(d+1/2s), trabecular osteoid surface (TOS) and bone formation rate in tissue level (Svf) were increased and osteoid maturation period (OMP) shortened in XW630 group. In osteoblast-like cells, both 3H-thymidine incorporation and cell count increased after treated with XW630 for 48. Treated with XW630 for 12 approximately 18h, inducible nitric oxide synthase (iNOS) activity and cGMP content increased in time-dependent manners.

CONCLUSIONS

XW630 enhanced bone activation frequency and increased trabecular connectivity, stability, and strength. The cellular mechanism related to effects of XW630 on bone formation in ovariectomized rats.

Changes of nitric oxide and its relationship with clinical features, intracranial pressure and outcome in acute head injury

To investigate the content and dynamics of nitric oxide (NO) in the cerebrospinal fluid (CSF) of patients with acute head injury and to clarify the relationship of NO with clinical features and intracranial pressure (ICP) as well as outcomes, 38 adults with acute head injury were studied. Glasgow Coma Scale (GCS) obtained at admission and Glasgow Outcome Scale (GOS) 3 months after injury was assessed. ICP was surveyed via intraventricular catheter and lumbar puncture and CSF samples were obtained simultaneously. NO was determined with Griess reagents. Results showed that NO peak content in the head injury group was significantly higher than that of the control group. During dynamic research, no peak content of mildly injured cases and severely injured ones appeared in different time windows respectively. The peak value of NO was distinctly higher in the severe group than in the mild group. NO peak value of the raised ICP group was remarkably higher than that of the normal ICP group. The peak value of NO was considerately higher in the poor outcome group than in the good outcome group. When the content of NO was over 6.5 mumol/L, the rate of poor outcome was increased. There existed a correlation between NO and GCS, ICP and GOS. It is concluded that the content of NO was increased in patients with acute head injury and the changes of NO had different time windows in severely injured patients and mildly injured ones. The more sever the injury, the higher the NO content; and the more serious the secondary brain injury and brain edema, the worse the outcomes. When NO is combined with GCS, GOS and ICP, it increases the accuracy of judgement to the degree of head injury and outcome.

[Comparison between carboplatin and cisplatin plus etoposide and carboplatin plus etoposide in the treatment of small cell lung cancer.]

BACKGROUND

To evaluate the effect and toxicity of combination chemotherapy with carboplatin and cisplatin plus etoposide (CPE regimen) and carboplatin plus etoposide (CE regimen) in the treatment of small cell lung cancer (SCLC) .

METHODS

Thirty-two patients with SCLC were treated with CPE and CE regimens , and each regimen had 16 cases respectively. There were 10 retreated cases in CPE group and 7 retreated cases in CE group.

RESULTS

The total response rate (CR + PR) was 81. 3 %(13/ 16) in CPE group , and 87. 5 %(14/ 16) in CE group ( P > 0. 05) respectively. The response rate of the retreated cases in CPE group was 60 %(6/ 10) , and 42. 9 %(3/ 7) in CE group ( P < 0. 05) . The bone marrow suppression rate was 71. 9 % in CPE group and 93. 8 % in CE group ( P < 0. 05) . There were no significant differences between other toxicity in both groups ( P > 0. 05) .

CONCLUSIONS

The therapeutic effect of CPE regimen in SCLC is similar to that of CE regimen , but the bone marrow suppression rate of CPE regimen is less severe than that of CE regimen. The therapeutic effect of CPE regimen is better than that of CE regimen for the retreated cases.

Expression and regulation of the chickenNkx-6.2 homeobox gene suggest its possible involvement in the ventral neural patterning and cell fate specification

Rapid accumulating evidence has suggested that the homeodomain transcription factors of the Nkx family play important roles in controlling vertebrate organ patterning and differentiation. In this study, we report the cloning, expression and regulation of a novel chicken homeobox gene, cNkx-6.2, whose expression is similar, but not identical, to that of mouse Nkx-6.2. The earliest expression of cNkx-6.2 was detected at the neural plate stage in the prospective midbrain and hindbrain regions. As the neural development proceeds, cNkx-6.2 expression was restricted in the ventral region of the entire neural axis except the forebrain region. At late stages of development, cNkx-6.2 expression is downregulated in the ventricular neuroepithelial cells, but subsequently upregulated in a sub-population of cells. Tissue recombination and explant culture experiments demonstrated that expression of cNkx-6.2 can be induced by the notochord signal and purified SHH protein, and repressed by BMP-4 and -7, indicating that the cNkx-6.2 expression can be influenced by both ventral and dorsal midline signals. Taken together, these studies have suggested two different roles for the cNkx-6.2 transcription factor: participating in the Shh-initiated ventral patterning during early CNS development and controlling cell fate specification and differentiation during late development.

[Thermal physiological analysis of man in an Intravehicular Activity space suit]

OBJECTIVE

To analyze the thermal physiological changes of man in a Intravehicular Activity (IVA) space suit.

METHOD

Combined second design was used to arrange 24 tests in 6 young male subjects wearing an IVA space suit at sea level.

RESULT

The relationship between common thermal physiological measurements and air ventilating parameters (air temperature, flow rate and its relative humidity) together with metabolic state (rest or work) of man were established in mathematical models. Possible applications of these models were illustrated. Metabolic heat production which influences the relations was also discussed.

CONCLUSION

Thermal physiological changes of man in the space suit were properly expressed by the mathematical models in this paper.

[Application of enzyme-linked immunosorbent assay for cholecystokinin]

An enzyme-linked immunosorbent assay for octapeptide cholecystokinin (CCK) has been developed. Using this method we distinguished two kinds of CCK-related peptides and is also useful for identified the compounds with CCK-like structure in tissue extracts, as well as different antipeptide antisera. The results showed that this method could be applied to preliminary structure analysis of CCK.

Msx1 is required for the induction of Patched by Sonic hedgehog in the mammalian tooth germ

We have used the mouse developing tooth germ as a model system to explore the transmission of Sonic hedgehog (Shh) signal in the induction of Patched (Ptc). In the early developing molar tooth germ, Shh is expressed in the dental epithelium, and the transcripts of Shh downstream target genes Ptc and Gli1 are expressed in dental epithelium as well as adjacent mesenchymal tissue. The homeobox gene Msx1 is also expressed in the dental mesenchyme of the molar tooth germ at this time. We show here that the expression of Ptc, but not Gli1, was downregulated in the dental mesenchyme of Msx1 mutants. In wild-type E11.0 molar tooth mesenchyme SHH-soaked beads induced the expression of Ptc and Gli1. However, in Msx1 mutant dental mesenchyme SHH-soaked beads were able to induce Gli1 but failed to induce Ptc expression, indicating a requirement for Msx1 in the induction of Ptc by SHH. Moreover, we show that another signaling molecule, BMP4, was able to induce Ptc expression in wild-type dental mesenchyme, but induced a distinct expression pattern of Ptc in the Msx1 mutant molar mesenchyme. We conclude that in the context of the tooth germ Msx1 is a component of the Shh signaling pathway that leads to Ptc induction. Our results also suggest that the precise pattern of Ptc expression in the prospective tooth-forming region is controlled and coordinated by at least two inductive signaling pathways.

[Study of morphologic effects of 4 Chinese herbs by bone histomorphometry in ovariectomized rats]

OBJECTIVE

To study the therapeutic effects of Chinese herbs Drynaria, Cynomorium, Epimedium and Chain Fern on osteoporotic ovariectomized (OVX) rat models.

METHODS

54 Wistar female rats at the age of 3 months were randomly divided into 2 groups: control groups and experimental group. The control group included: normal groups (N), shamed oprations group(S) and ovariectomized group (OVX) (10 in each group); The experimental group: group A (Drynaria), group B (Cynomorium), group C (Epimedium) and group D (Chain Fern) (6 in each group). Each of the experimental groups was fed separately with the 4 Chinese herbs (0.25 g/100 g B.W/day) respectively by mouth every day for 2 months. Double tetracycline labels were carried out on these animals before the sacrifice. Their left tibia was reserved for the preparation of bone specimen and was studied by bone histomorphometry.

RESULTS

The percentage of trabecular volume in total bone volume (TV/TBV) decreased significantly in OVX rats as compared with shame group (P < 0.01). However, after treatment with Drynaria or Epimedium, TV/TBV increased significantly as compared with that before treatment (P < 0.05). The surface area of tetracycline label in Drynaria group lowered and osteoid percentage increased in Epimedium group.

CONCLUSIONS

The 4 Chinese herbs have some therapeutic effects on osteoporotic rat models. Drynaria and Epimedium appeared to work better.

Molecular cloning and expression of human grap-2, a novel leukocyte-specific SH2- and SH3-containing adaptor-like protein that binds to gab-1

The SH2- and SH3-containing adaptor molecules serve to recruit cytosolic signal-transducing molecules to the activated receptor tyrosine kinases. In this study, we report the molecular cloning of a novel adaptor-like protein, Grap-2 (Grb-2 related adaptor protein 2), using the multisubstrate docking protein Gab-1 as bait in the yeast two-hybrid system. Sequence analysis revealed that Grap-2 contains a SH3-SH2-SH3 structure that has a high degree of sequence homology to those of the Grb-2 and Grap adaptor molecules. However, unlike in Grap and Grb-2, the SH2 and the C-terminal SH3 domains of Grap-2 are separated by a 120-amino-acid glutamine-rich sequence that shows no apparent homology to any known molecule or structural motif. The C-terminal SH3 domain of Grap-2 alone is sufficient to bind to Gab-1. Furthermore, Northern blot analysis demonstrated that Grap-2 has two major transcripts of 1.4 and 4.0 kb that can only be detected in tissues rich in leukocytes and in two leukemia cell lines. This highly restricted pattern of expression suggests that Grap-2 may participate in leukocyte-specific protein tyrosine kinase signaling.

Excitatory amino acids in cerebrospinal fluid and their relations with clinical features and outcomes in acute head injury

OBJECTIVE

To determine the contents and dynamics of excitatory amino acids (EAAs), glutamate (GLU) and aspartate (ASP) in the cerebrospinal fluid (CSF) of patients with acute head injury and to clarify the relationship of EAAs with clinical features and outcomes.

METHODS

Forty-two adults with acute head injury were included. Glasgow coma scale (GCS) obtained at admission and Glasgow outcome scale (GOS) obtained three months post-injury were assessed. Samples of CSF were obtained via ventricular or lumbar puncture every 24 hours. GLU and ASP in CSF were analyzed by reversed-phase HPLC with a fluorescent detector. Nine control subjects were adults with lumbar anesthesia but without neurological diseases.

RESULTS

The peak concentration of GLU and ASP of head-injured group was significantly higher than that of the control group. Dynamic research on severely injured ones indicated that the peak value of GLU mostly appeared within 48 hours post-injury; it decreased with the improving or remaining of the neurological status, and increased with the deterioration, but was still higher than that of the control seven days post-injury. The peak value of EAAs of severely injured patients was conspicuously higher than that of mildly injured group. There was a significant negative correlation between the peak values of GCS and EAAs. The peak value of EAAs in patients with poor outcome was remarkably higher than that in patients with good outcome. GOS was closely correlated to the peak value of EAAs. When the concentration of GLU was over 7 mumol/L, the rate of poor-outcome increased markedly.

CONCLUSION

The content of EAAs in CSF increases following acute head injury and remains higher at least a week post-injury in severely injured patients. The more severe the trauma, the more obvious the excitotoxicity induced by EAAs; the more serious the secondary brain insult and the brain edema will be, the worse the outcome, naturally.

Construction of a modular yeast two-hybrid cDNA library from human EST clones for the human genome protein linkage map

Identification of all human protein-protein interactions will lead to a global human protein linkage map that will provide important information for functional genomics studies. The yeast two-hybrid system is a powerful molecular genetic approach for studying protein-protein interactions. To apply this technology to generate a human protein linkage map, the first step is to construct two-hybrid cDNA libraries that cover the entire human genome. With a homologous recombination-mediated approach, we have constructed a modular human EST-derived yeast two-hybrid library in the Gal4 activation domain-based vector, pACT2. Quality analysis of this library indicated that the approach of constructing two-hybrid cDNA libraries from individually arrayed human EST clones is feasible, and such a two-hybrid library is suitable for detecting protein-protein interactions. This is also the first time that a comprehensive two-hybrid system cDNA library has been constructed from a collection of individually arrayed EST clones.

Cloning and expression pattern of chicken Pitx2: a new component in the SHH signaling pathway controlling embryonic heart looping

Asymmetry along the left-right axis of the embryo is a vital feature of vertebrate embryogenesis. In this study, we report the isolation and characterization of a bicoid-related homeobox gene, cPitx2, which displays left-right asymmetric expression during early chick embryogenesis. Asymmetric expression of cPitx2 is first detected at stage 7 and is restricted to mesodermal tissues on the left side of the embryo including the left sided lateral mesoderm, the left sided precardiac mesoderm, and the left half epimyocardium of the primitive heart. cPitx2 is also detected in the presumptive blood islands and endothelia of the embryonic blood vessels. Implantation of Sonic hedgehog (SHH) protein soaked beads on the right side of embryos induced ectopic cPitx2 expression on that side. Based on these observations, we suggest that cPitx2 is a component in SHH signaling pathway and plays a role in determining left-right asymmetry and in vasculogenesis during avian embryogenesis.

[Relationship between the toxigenicity and ribotype distribution of Pseudomonas cocovenenans subsp. farinofermentans]

By rDNA fingerprinting technique, ribotype discrimination analysis was conducted for exploring the relationship between the toxigenicity and ribotype distribution of 42 strains of Pseudomonas cocovenenans subsp. farinofermentans. The results showed that 73.8 percent of the strains were toxigenic, which were distributed within the most ribotype and isolated from either food poisoning samples or normal food samples. The other strains were not toxigenic; which were isolated from normal food samples and distributed only within a few ribotypes. Since the most clones of P. cocovenenans subsp. farinofermentans were toxigenic, their potential hazard should be concerned.

Control of anteroposterior and dorsoventral domains of Nkx-6.1 gene expression relative to other Nkx genes during vertebrate CNS development

Here we report the isolation, sequence and developmental expression in the central nervous system of several members of the chicken and mouse Nkx gene family. These are among the earliest genes to be regionally expressed in the neural plate; they are expressed just above the axial mesendoderm (prechordal mesendoderm and notochord). Each Nkx gene has a distinct spatial pattern of expression along the anterior-posterior axis of the ventral central nervous system: Nkx-2. 2 is expressed along the entire axis, whereas Nkx-2.1 is restricted to the forebrain, and Nkx-6.1 and Nkx-6.2 are largely excluded from the forebrain. They are also expressed in distinct patterns along the dorsal-ventral axis. These genes are expressed in both the ventricular and mantle zones; in the mantle zone Nkx-6.1 is co-expressed with Islet-1 in a subset of motor neurons. Like other Nkx genes, expression of Nkx-6.1 is induced by the axial mesendoderm and by sonic hedgehog protein. BMP-7 represses Nkx-6.1 expression. While the notochord can induce Nkx-6.1 expression in the anterior neural plate, sonic hedgehog protein does not, suggesting that the notochord produces additional molecules that can regulate ventral patterning.

[Surgical management of closed injury of mitral valve: report of four cases]

OBJECTIVE

To show the experience in dealing with mitral valve injury caused by trauma.

METHODS

Four cases of closed injury of mitral valve were treated.

RESULTS

Two of the four patients presented ruptured chordae of mitral valve and were cured with annutoplasty plus repair of the chordae and mitral valve replacement respectively. One presented tearing of mitral valve leaf and pseudoaneurysm of the femoral artery, which were complicated by infective endocarditis. The patient was cured with emergency operation to repair the lesions and remove pseudoaneurysm and neoplasm in the mitral valve. Another patient, who received mitral valve replacement 8 years before, presented ruptured valve-hook of the prosthesis and died of acute heart failure without prompt operation. The diagnosis was confirmed by autopsy.

CONCLUSIONS

The disease is easy to misdiagnose and once the diagnosis is established surgical intervention should be performed early. Emergency operation is necessary if acute heart failure occurs or infective endocarditis is complicated.

[Study on the molecular epidemiology characteristics of Pseudomonas cocovenenans subsp. farinofermentans isolated from China with rDNA fingerprinting]

After the chromosomal DNA digestion by Bgl II and EcoRV, rDNA fingerprinting for Pseudomonas cocovenenans subsp. farinofermentans was made using biotin-labeled 16S + 23S rDNA as a probe. Fifty one strains of P. cocovenenans subsp. farinofermentans isolated from some areas of China were divided into 20 ribotyes, 52.9 percent of which were RT6, 9 and 2. In most cases, there were 2 or more ribotypes in each province or city. Though same ribotypes were isolated from different provinces, each ribotype existed in part of an area. The ribotype of RT6 was detected in samples from 4 incidents of food poisoning in Guizhou, Jiangsu and Hebei provinces, which indicated that these incidents may be caused by the same clone. With discrimination and cluster analysis of ribotypes, the rDNA fingerprinting may effectively contribute to analyzing the homogeneity of different strains, tracing the transmission route, and exploring the evolution and epidemiological characteristics of P. cocovenenans subsp. farinofermentans.

Molecular control of odontogenic patterning: positional dependent initiation and morphogenesis

We have previously proposed that the patterning of the mammalian dentition is determined by an odontogenic homeobox code, whereby positional specification of odontogenic ectomesenchymal cell populations in a given region of the first branchial arch are determined by the combination of different homeobox genes expressed, described in detail in (1). Here we describe the first functional evidence for such a mechanism, and show that development of different types of teeth is controlled by independent genetic pathways. We suggest a mechanism whereby patterning is determined by position dependent control of tooth germ initiation, and propose that the pathway of morphogenesis is directly linked to the early mesenchymal expression of homeobox genes.

[Comparative study of tetracycline-estrone and estrone effects on bone histomorphometric parameters in ovariectomized rats]

OBJECTIVE

To compare the effects of tetracycline-estrone (TE) and estrone (E) on bone histomorphometric parameters of femoral distal diaphysis in ovariectomized (OVX) rats.

METHODS

Twenty female rats were randomly allocated into four groups, 5 rats in each: tetracycline-estrone (TE), estrone (E), OVX and sham operation (S). The OVX rats were used as a model for osteoporosis. After being fed with TE or E for 13 weeks, all rats were sacrificed. The effects of TE and E on bone microarchitecture and dynamics were studied by bone histomorphometry.

RESULTS

The histomorphometric data showed that the connectivity of trabecular bone in TE and E groups was significantly improved in comparision with that in S group (P < 0.05). The dynamic data indicated that in TE and E group, the tetracycline labelled and osteoid surfaces were remarkably increased in comparision with those in OVX group, especially the data in TE group were significantly higher than those in E group and other two groups (P < 0.05).

CONCLUSIONS

The connectivity of trabecular bone could be significantly improved by both TE and E. The activation frequency seemed to be higher in TE group than that in E group.

Minimum length of sequence homology required for in vivo cloning by homologous recombination in yeast

With efficient homologous recombination in Saccharomyces cerevisiae, a rapid in vivo cloning technique has been available. Here we demonstrated that 30 bp of a homologous sequence at each end of a DNA fragment is sufficient to integrate the fragment into a linearized plasmid in yeast. To obtain a high yield of recombination transformants, however, more than 60 bp are desirable. Interestingly, we observed that 20 bp of homology at one end of a DNA fragment is sufficient for efficient recombination provided that the other end contains 80 bp of homologous sequence. Some applications, including high-throughput transferring of EST inserts to the yeast expression systems for the Human Genome Project, are discussed.

Mutations of the homeobox genes Dlx-1 and Dlx-2 disrupt the striatal subventricular zone and differentiation of late born striatal neurons

The striatum has a central role in many neurobiological processes, yet little is known about the molecular control of its development. Inroads to this subject have been made, due to the discovery of transcription factors, such as the Dlx genes, whose expression patterns suggest that they have a role in striatal development. We report that mice lacking both Dlx-1 and Dlx-2 have a time-dependent block in striatal differentiation. In these mutants, early born neurons migrate into a striatum-like region, which is enriched for markers of the striosome (patch) compartment. However, later born neurons accumulate within the proliferative zone. Several lines of evidence suggest that mutations in Dlx-1 and Dlx-2 produce abnormalities in the development of the striatal subventricular zone and in the differentiation of striatal matrix neurons.

[Thermoregulation under simulated weightlessness]

The effect of simulated weightlessness on thermoregulation was studied in 5 subjects. The experiment consisted of 3d baseline measurements, 7d head-down bed rest and 2d recovery. Circadian rhythm was assessed by continuous measurements of rectal temperature and skin temperature with 2h intervals. Heat Stress Protein 70 (HSP70) was measured by Western-blot Dot method and the facial surface temperature distribution was measured by HR-2 infrared thermography. The results showed that rectal temperature keeps the wake-sleep variation, but the circadian rhythm changed during bed rest, and the change of rectum temperature rhythm appeared mainly in the early-days of bed rest; HSP70 and facial surface temperature increased during bed rest.

[Physiological effects of cabin temperature decrease on human]

To study effects of cabin temperature on human body, changes in rectal temperature, local skin temperature, local skin heat fluxes and skin infrared thermogram were observed in 5 male subjects dressed in different thermal insulation clothings under 20 degrees C, 15 degrees C and 10 degrees C cabin temperatures. The results showed that, average skin temperature and tip temperature obviously dropped, and skin heat fluxes increased with falling of cabin temperature, and changes of local skin infrared thermogram were significant. Subjective feeling were comfortable and cool at cabin temperature of 20 degrees C and 15 degrees C respectively. While subjective feeling was cold and there was a thermal debt of body 144 kJ/m2 at 10 degrees C which indicated that it was slightly cold but tolerable. The results may be valuable in determining the lowest tolerable limit of cabin temperature.

Role of the Dlx homeobox genes in proximodistal patterning of the branchial arches: mutations of Dlx-1, Dlx-2, and Dlx-1 and -2 alter morphogenesis of proximal skeletal and soft tissue structures derived from the first and second arches

The Dlx homeobox gene family is expressed in a complex pattern within the embryonic craniofacial ectoderm and ectomesenchyme. A previous study established that Dlx-2 is essential for development of proximal regions of the murine first and second branchial arches. Here we describe the craniofacial phenotype of mice with mutations in Dlx-1 and Dlx-1 and -2. The skeletal and soft tissue analyses of mice with Dlx-1 and Dlx-1 and -2 mutations provide additional evidence that the Dlx genes regulate proximodistal patterning of the branchial arches. This analysis also elucidates distinct and overlapping roles for Dlx-1 and Dlx-2 in craniofacial development. Furthermore, mice lacking both Dlx-1 and -2 have unique abnormalities, including the absence of maxillary molars. Dlx-1 and -2 are expressed in the proximal and distal first and second arches, yet only the proximal regions are abnormal. The nested expression patterns of Dlx-1, -2, -3, -5, and -6 provide evidence for a model that predicts the region-specific requirements for each gene. Finally, the Dlx-2 and Dlx-1 and -2 mutants have ectopic skull components that resemble bones and cartilages found in phylogenetically more primitive vertebrates.

Mutation of the Emx-1 homeobox gene disrupts the corpus callosum

Expression of the Emx-1 homeobox gene is largely restricted to the developing and mature cerebral cortex. To study its function, two lines of mice were generated using gene targeting methods that have a deletion that includes the N-terminal coding region of Emx-1. Mice homozygous for the deletion were viable and fertile and exhibited no obvious behavioral defects. However, 100% of homozygous mice lack most or all of their corpus callosum, the principle fiber tract that connects the left and right cerebral hemispheres. Heterozygotes show partial penetrance for the corpus callosum abnormality. The histology and various molecular properties of the cerebral cortex appear normal in the mutant mice.

Sequence, organization, and transcription of the Dlx-1 and Dlx-2 locus

There are at least five murine Dlx genes that are related to the Drosophila Distal-less homeobox gene. The Dlx genes are primarily expressed in the developing forebrain, derivatives of the cranial neural crest and restricted epidermal craniofacial and limb domains. Dlx-2 is required for differentiation of subsets of cranial neural crest and forebrain cells. Previous genomic studies have shown that Dlx-1 and Dlx-2 are linked on mouse chromosome 2, near the HoxD cluster. Here we report a detailed analysis of the nucleotide sequence (approximately 14 kb), organization, and transcription of the murine Dlx-1 and Dlx-2 locus. In addition, we show that Dlx-1 makes multiple sense transcripts and at least one antisense transcript, whereas Dlx-2 makes one major transcript. The sequence of the human Dlx-2 gene is reported and is compared to that of the murine gene. Finally, sequence analysis of the deduced protein sequences reveals several candidate functional domains.

[Application of laparoscopic technique in gastrointestinal surgery]

OBJECTIVE

To evaluate the feasibility of gastrointestinal procedures guided by laparoscopy in 42 patients aged from 18 to 86 years.

METHODS

We performed 10 Billroth II gastrectomies, 10 resections of gastric benign tumor, 11 repairs of duodenal perforation, 2 highly selective vagotomies, 5 resections of small bowel, 3 adhesiolyses of small bowel and 1 ileocolectomy. The operations were performed under general anesthesia with endotracheal intubation and through four portals (10mm). The omentum and mesentery were mobilized with an electrocautery and vessels controlled with either Endoclip or ELC. The reconstructions of the digestive tract were performed entirely intraabdominally with ELC.

RESULTS

Except one patient receiving Billroth II gastrectomy complicated with postoperative bleeding had to be reoperated, the remaining 41 patients were successfully treated. All the 41 patients could walk and take fluids on the second postoperative day. The average length of hospitalization after operation was 7.5 days.

CONCLUSIONS

Laparoscopic gastrointestinal procedures for selected cases can be carried out safely and effectively with decreased postoperative pain and rapid recovery. It may change the surgical management of some benign gastrointestinal diseases.

Null mutation of Dlx-2 results in abnormal morphogenesis of proximal first and second branchial arch derivatives and abnormal differentiation in the forebrain

Genetic analysis of the development and evolution of the vertebrate head is at a primitive stage. Many homeo box genes, including the Distal-less family, are potential regulators of head development. To determine the function of Dlx-2, we generated a null mutation in mice using gene targeting. In homozygous mutants, differentiation within the forebrain is abnormal and the fate of a subset of cranial neural crest cells is respecified. The latter causes abnormal morphogenesis of the skeletal elements derived from the proximal parts of the first and second branchial arches. We hypothesize that the affected skull bones from the first arch have undergone a transformation into structures similar to those found in reptiles. These results show that Dlx-2 controls development of the branchial arches and the forebrain and suggests its role in craniofacial evolution.

[Application of laparoscopic technique in splenic surgery]

Five patients of splenic operations had been performed by laparoscopic technique. Patients' ages ranged from 19 to 47, with an average of 31. Four were males and one was female. The procedures included splenectomy 1 patient, deroofing of splenic cyst (1), and hemostasis of splenic injuries (3). The results indicated that all the procedures were successful, and the average length of postoperative stay was 6.5 days. There were no complications. The advantages of laparoscopic splenic surgery include minimal incision, less postoperative pain and rapid recovery. It should be stressed, however, that laparoscopic splenic procedures should be performed cautiously for selected indications only and by surgical endoscopists well trained.

The small heat shock protein hsp27 is correlated with growth and drug resistance in human breast cancer cell lines

An emerging body of evidence suggests that the heat shock proteins (hsp) may be involved in drug resistance. When hsp are induced by elevated temperatures, resistance to doxorubicin (Dox), but not to other commonly used chemotherapeutic agents, is induced in breast cancer cells. To evaluate the role of hsp27 in this phenomenon, we have transfected MDA-MB-231 breast cancer cells, which normally express low levels of hsp27, with a full-length hsp27 construct. These hsp27-overexpressing cells now display a 3-fold elevated resistance to Dox. Anchorage-dependent proliferation and anchorage-independent growth were also increased 2-4-fold in these transfectants. We have also derived a MCF-7 breast cancer cell line with amplified endogenous hsp27 which is highly resistant to Dox. When these cells are transfected with an antisense hsp27 construct, they are rendered sensitive to Dox (3-fold) with anchorage-dependent as well as anchorage-independent growth, similarly decreased. These results suggest that hsp27 specifically confers Dox resistance in human breast cancer cells and, furthermore, that hsp27 may be involved in the regulation of cell growth.