[Factors affecting transformation of Agrobacterium tumefaciens and their application on cereals]

Agrobacterium tumefaciens mediated genetic transformation is the method most widely used in plant transformation. How to improve its transformation efficiency and extend its host range to include most cereals is what people concern about. There are many factors that influence the transformation efficiency, including the wounding response of plants, attachment of bacteria, induction of virulent gene, DNA repair and replication activity of plant cells, state of explant, etc. Recent research has proved that cerelas can be transformed effectively by A. tumefaciens under suitable conditions. This paper reviewed the recent progress in the two aspects.

[Nonsyndromic cleft lip with or without cleft palate in Chinese population: analysis of 3766 cases]

A retrospective study was conducted to evaluate the variation trend in the incidence and epidemiological characteristics of nonsyndromic cleft lip with or without cleft palate in Chinese population. From 1988 to 1992, data were collected from more than 500 hospital-based units involved in a monitoring program and were analyzed by the National Center for Birth Defects Monitoring. The monitored subjects were the hospitalized births from 28 weeks gestation to a period within 7 days after delivery, which included 3246 408 perinatals and 3766 cases. The total incidence of nonsyndromic cleft lip with or without cleft palate was 11.6/10,000; the total incidence of celft lip alone was 3.8/10,000 and that of cleft lip with cleft palate was 7.8/10,000; no significant variation was noted in the annual incidence from 1988 to 1992. The incidence in males was 13.3/10,000, and 9.5/10,000 in females; there was a significant difference (P < 0.01). Of all the 3766 cases, cleft lip with cleft palate accounted for 67%, unilateral cleft lip 28% and unilateral cleft lip with cleft palate 43%. Left cleft lip and left cleft lip with cleft palate constituted 21% and 29% respectively. The sex-ratio was 1.6:1 for nonsyndromic cleft lip with or without cleft palate. It could be concluded that the incidence of nonsyndromic cleft lip with or without cleft palate showed no variation trend in China. Although no difference was found between urban and rural areas, the susceptibility to the defect was higher in males than in females. Cleft lip with cleft palate was more common than other types. There was a predominance of unilateral defects, of which most were on the left side.

[Cloning and primary analysis of 3 'end genome of two alphaviruses isolated from Hainan Province of China]

OBJECTIVE

To further characterize the HBbl7 and Ml viruses isolated from Hainan Province by molecular biology.

METHODS

The fragment containing partial El and 3'untranslated region of each of the viral isolate was amplified by RT-PCR, then subcloned. Recombinant was screened and sequenced. Analysis and comparison were carried out.

RESULTS

1.6kb fragment was amplified from HBbl7 and a 1.3kb was from Ml Comparison of sequences showed, in 3'untranslated region the nucleotide homology between HBbl7 and T48, the prototype of Ross River virus, is 99%, between Ml and Sagiyama virus is 98%. In the partial El sequence, the nucleotide (amino acid) homology between HBbl7 and T48 is 99%(99%),between Ml and Sagiyama virus is 97%(99%), and between Ml and Cetah virus is 94% (98%).

CONCLUSIONS

Sequence analysis showed HBb17 virus belongs to Ross River virus, Ml virus belongs to Sagiyama virus or Cetah virus.

[Experimental studies on exons 5-8 of p53 gene mutation in laryngeal squamous cell carcinoma]

This study was designed to detect the point mutations of exons 5-8 of p53 gene in laryngeal squamous cell carcinoma (LSCC) and analyze their relationship. The detection of fresh tumor samples from LSCC patients was performed using silver staining PCR-SSCP method. From among 60 patients samples, 47 were positive in SSCP. Mutation rate was 78.3% (47/60). The results showed that the prevalence of p53 mutations in LSCC subjected to silver staining PCR-SSCP test were 50% (30/60) in exon 5, 11.67%(7/60) in exon 6, 41.6%(25/60) in exon 7, and 25%(15/60) in exon 8. The majority of the mutations were found in exon 5 and exon 7. Exon 5 and exon 7 of p53 gene may be the mutation hotspot in LSCC; they may be the critical position easily attacked by some carcinogen factors relating to LSCC.

Efficient method for evaluation of the diffraction efficiency upper bound of diffractive phase elements

The theoretical diffraction efficiency upper limit of diffractive phase elements (DPE's) with finite apertures is investigated. A successful numerical method of evaluating the efficiency upper bound of DPE's is proposed. The method includes a hybrid optimization procedure that combines a genetic algorithm with the conjugate gradient method. This efficient global optimization technique can also be used to design DPE's. Simulation computations are detailed for rotationally symmetric beam shaping in which a Gaussian profile laser beam is converted into a uniform beam. Numerical results demonstrate that the estimated diffraction efficiency upper bound is consistent with the design results.

The structure of an HIV-1 specific cell entry inhibitor in complex with the HIV-1 gp41 trimeric core

The three-dimensional structure of the complex between an HIV-1 cell-entry inhibitor selected from screening a combinatorial library of non-natural building blocks and the central, trimeric, coiled-coil core of HIV-1 gp41 has been determined by X-ray crystallography. The biased combinatorial library was designed to identify ligands binding in nonpolar pockets on the surface of the coiled-coil core of gp41. The crystal structure shows that the non-peptide moiety of the inhibitor binds to the targeted cavity in two different binding modes. This result suggests a strategy for increasing inhibitor potency by use of a second-generation combinatorial library designed to give simultaneous occupancy of both binding sites.

[Acoustic densitometry for quantification of renal allografts microcirculation and microstructure]

OBJECTIVE

To establish a new method for observing renal allografts microcirculation and microstructure with acoustic densitometry (integrated backscatter, contrast, second harmonics).

METHODS

27 patients with renal allografts were investigated by Doppler, IBS, contrast and second harmonics. Renal allografts failed age in 5 patients 20-61 years. Intravenous injection of SHU-508A was given, compared with pre-injection by quantitative assessment of acoustic densitometry (AD) of renal microstructure.

RESULTS

There was a significant difference in the peak intensity, the area under the curve and the half-time of wash-out between pre-injection and injection contrast agent. The wish-in and wish-out curve was shown in a peak shape. The renal allografts with acute rejection were significantly lower than the control group in AD (P < 0.05). No contrast opacification of renal microstructure was present in 5 failed renal allografts and the wish-in and wish-out curve appeared in a straight line shape.

CONCLUSION

AD is safe, and efficient in assessing renal allografts microstructure. It more sensitive in detecting allograft complication such as rejection than Doppler.

Neuropeptide Y secretion from bovine chromaffin cells inhibits cyclic AMP accumulation

Neuropeptide Y (NPY) is secreted from bovine chromaffin cells in response to nicotinic receptor stimulation and may exhibit autocrine, paracrine or endocrine effects. Stimulation of bovine chromaffin cells with nicotine followed by the addition of forskolin (FSK) to the media results in a decrease in cyclic AMP accumulation compared to that seen in the absence of nicotine. Pertussis toxin (PTX) treatment or the addition of BIBP 3226, a selective NPY Y1 receptor antagonist prevents the inhibitory effect of nicotine. Fractionation of media obtained from cells stimulated with nicotine reveals an NPY-like substance that inhibits FSK-stimulated cAMP accumulation. Thus, an NPY-like substance can be secreted from bovine chromaffin cells in quantities sufficient to inhibit FSK-stimulated cAMP accumulation. These results suggest that NPY can act in an autocrine fashion to regulate chromaffin cell function.

Analysis of K-ras and p53 mutations in mesotheliomas from humans and rats exposed to asbestos

Malignant mesothelioma is known to be associated with asbestos exposure. However, the mechanism of mesothelial carcinogenesis in relation to the activation of proto-oncogenes or inactivation of tumor suppressor genes remains unclear. In this study, the PCR-Primer Introduced Restriction Site (PCR-PIRS) assay was employed to examine mutations in the K-ras proto-oncogene in mesothelioma tissues from workers exposed to asbestos and from rats treated with asbestos. Mutations in exons 5-8 of the p53 tumor suppressor gene were determined by direct DNA sequence analysis. Results of the PCR-PIRS analysis revealed no mutations in codons 12, 13 or 61 of the K-ras gene in any of the 17 human or 22 rat mesothelioma tissue samples. These results were confirmed by direct DNA sequence analysis. No mutations were found in exons 5-8 of the p53 gene in any of the mesothelioma tissue samples analyzed. These results and the results reported by others indicate that the K-ras proto-oncogene and p53 tumor suppressor gene may not play a critical role in the induction of mesothelioma by asbestos either in humans or in rats.

Application of hemodilution in microsurgical free flap transplantation

The intra-operative hemodilution and blood auto-transfusion is a blood-saving technique that can be performed when major blood loss is expected. The effects of this technique were studied in 30 microsurgical free flap transplantation patients. Between 400-600 ml blood was collected from the patients before surgery. The patients received dextran, a balanced salt solution, and glucose with the ratio of 3:1 to the collected blood volume, bleeding, and urine before the blood auto-transfusion. There were no significant changes in RBC, HCT, MCV, blood pressure, or heart rate. Of the 30 free flaps, 28 were successful with a 93.3% survival rate. The safety of intra-operative hemodilution and autologous blood transfusion in microsurgery as well as the effect of hemodilution on transplanted flap survival are discussed in this study.

Detection of mosaic chromosome 21 aneuploidy in vivo with CB-FISH method

OBJECTIVE

To explore the mechanism by which the ratio of mosaic diploid cells in vivo increased in trisomy 21 cases.

METHODS

Fluorescence in situ hybridization (FISH) with pericentric DNA probes specific to human chromosome 21 to the binucleated cells cytokinesis- blocked by cytochalasin-B(CB), namely, CB-FISH method.

RESULTS

The mean frequency of diploid cells (1.69%+/-1.07%) was significantly higher than that of tetrasomy 21 cells(0.042%+/-0.064%)(P=0.000) in 12 trisomy 21 cases aged 0-9 years (mean 4 years) in vivo; whereas the incidence of spontaneous monosomy 21 cells (0. 265%+/-0.13%) was close to the frequency of trisomy 21 cells (0. 225%+/-0.184%) in 20 control individuals aged 0-10 years (mean 5 years). The frequency of cells undergone chromosome 21 nondisjunction was 0.822%+/-0.554% in cultured trisomy 21 cells, which was significantly higher than that in the cultured diploid cells (0.369%+/-0.25%). However, the rates of cells with chromosome 21 loss in the two cultured cell lines (0.01%+/-0.03% vs 0.043%+/-0.049%) were not significantly different. In both cultured cell lines, chromosome 21 nondisjunction occurred more frequently than loss.

CONCLUSION

The increased frequency of diploidies in trisomy 21 cases may result from the accumulation of diploid cells originating from malsegregation of chromosome 21 in trisomic cells rather than the increase of chromosome 21 loss.

[A report of 115 cases of amputation after electric injury]

OBJECTIVE

To analyze the main features of amputation subsequent to electric injury.

METHODS

One hundred and fifteen cases of amputation were analyzed with the purpose to define the indication, the optimal level, operational methods and the prognosis.

RESULTS

The incidences of amputation in this group were 45.4% for upper and 14.9% for lower extremities, respectively. The indications were total necrosis of the extremities, secondary necrosis of the extremities due to the thrombosis, bleeding and rupture of the major supplying arteries and failure to restore severely injured tissue. The commonest amputation levels were the mid third and the upper third of the forearms. The primary healing rate was 63.5%.

CONCLUSION

It was very important to identify the optimal indications, the proper levels and operational methods for the amputation after electric injury, so as to make stumps more suitable for the installation of artificial limbs to restore better function.

[Relationship between the changes of serum free fatty acids and insulin resistance in type 2 diabetics]

The purpose of this study was to investigate the changes of serum free fatty acids (FFA) in fasting state and absorptive state and the relationship between FFA changes and insulin resistance in the patients with type 2 diabetes (DM2). 75 g of glucose were given to 60 patients with DM2. Fasting serum FFA, serum insulin levels and the same parameters 2 h after glucose load were measured by calorimetric and RIA methods. Fasting and 2 h after oral glucose tolerance test (OGTT) plasma glucose(PG) levels were also assessed by using glucose oxidase method. The results showed the levels of serum FFA, PG and insulin of fasting and after glucose load in the patients were significantly increased and their insulin-sensitive (ISI) was remarkably decreased as compared with those in 30 normal controls, P < 0.05. Multiple stepwise regression analysis showed that the FFA level of 2 h after OGTT was negatively correlated with ISI, P = 0.0304. The results suggest that in patients with DM2, the levels of fasting and absorptive FFA are significantly elevated, which is negatively correlated with the decline of ISI, implying the association of abnormal fasting and absorptive FFA and insulin resistance in patients with type 2 diabetes.

[Analysis on 2158 neural tube defects diagnosed prenatally by ultrasound examination]

A retrospective survey was made to study the prenatal diagnosis on neural tube defects(NTD) by ultrasound examination from 1990 to 1993 in China. A total of 2158 livebirths and stillbirths affected by NTD with 28 weeks or more of gestation were investigated in 233 hospitals of 28 provinces, municipalities and autonomous regions all over the country. The results showed that 61.8% of the NTD were diagnosed prenatally, and 56.5% of the NTD were diagnosed by ultrasound examination. The ratios of anencephaly, myelocele and meningocele diagnosed prenatally by ultrasound examination were 66.7%, 62.5% and 52.5% respectively. Thoracic(46.4%) and lumbar (43.4%) spina bifida were diagnosed more frequently than cervical(35.5%) and sacral(31.7%) spina bifida. The ratios of prenatal diagnosis on NTD by ultrasound examination in provincial, municipal, county, and factory hospital units were 55.7%, 59.4%, 49.0% and 57.2% respectively. The ratios of prenatal diagnosis of NTD by ultrasound examination from 1990 to 1993 were 53.5%, 55.8%, 60.7% and 54.7% respectively. There was an increase in the prenatal diagnosis of NTD by ultrasound examination from 1990 to 1993. The ratios of prenatal diagnosis of NTD in county hospitals by ultrasound examination were relatively low. Anencephaly, myelocele and meningocele were more frequently diagnosed by prenatal ultrasound examination.

[Survey of the patients with oblique facial clefts in China]

OBJECTIVE

A descriptive study was conducted to investigate the epidemiological characteristics of oblique facial clefts in China.

METHODS

From 1987 to 1992, data were collected from more than 500 hospital-based units involved in a monitoring program and were analyzed by the National Center for Birth Defects Monitoring. The monitored subjects were the hospitalized births from 28 weeks gestation to a period within 7 days after delivery.

RESULTS

There were 71 cases of oblique facial clefts in 4,489,692 births with an incidence of 0.16/10(4) in China. The incidence of oblique facial clefts in the rural and urban areas were 0.19/10(4) and 0.14/10(4) respectively, 0.18/10(4) in males and 0.12/10(4) in females. No significant differences were found. The unilateral oblique facial clefts were counted for 80%, and bilateral cases 20%. The incidence of unilateral oblique facial clefts in males is higher than that in females. The perinatal mortality was as high as 51%. There are 76% cases with associated abnormalities, most of which involved the maxillofacial region. The most common associated abnormality is cleft lip with cleft palate.

CONCLUSION

The incidence of oblique facial clefts in China is the same as those in other countries. There is an unilateral predominance in this defect, especially in males. The perinatal mortality of this defect is high.

Two novel fibrillin-2 mutations in congenital contractural arachnodactyly

Congenital contractural arachnodactyly (CCA) is an autosomal dominant connective tissue disorder, comprising marfanoid habitus, flexion contractures, severe kyphoscoliosis, abnormal pinnae, and muscular hypoplasia. It is now known that mutations in the gene encoding fibrillin-2 cause CCA. Interestingly, mutations described to date cluster in the fibrillin-2 region homologous to the so-called neonatal Marfan syndrome region of fibrillin-1. Thus, it has been hypothesized that the relative infrequency of CCA compared with the Marfan syndrome is due to the limited region of the gene targeted for mutations. In support of the above hypothesis, we report here the finding of two additional FBN2 mutations in CCA, C1141F (exon 26) and C1252W (exon 29). In addition, a new 3' UTR polymorphism is also described.

Indomethacin induces apoptosis and inhibits proliferation in chronic myeloid leukemia cells

A nonsteroidal anti-inflammatory drug (NSAID)--indomethacin (IN), was found to induce apoptosis and inhibit proliferation of K562 cells and primary culture bone marrow cells from six chronic myelogenous leukemia (CML) patients. IN induced cells apoptosis and inhibited cells proliferation in a dose-and time-dependent manner, the optimum IN concentration and incubation time for eliciting these effects were 400 micromol/l and 72 h, respectively. A synergic effect on Vp-16 (2.5 microg/ml) induced apoptosis was observed when combined with 100 micromol/l IN in K562 cells. RT-PCR results showed that IN down-regulated Bcl-2 mRNA expression, and did not change Bax mRNA expression; Western blot results confirmed that IN inhibited Bcl-2 protein expression, no influence was found on the translative level of bax protein. Our study indicate that IN induce apoptosis of CML cells by down-regulating Bcl-2 expression partially, and there is a potential significance in the treatment of CML.

New types of solitary wave solutions for the higher order nonlinear Schrodinger equation

We present new types of solitary wave solutions for the higher order nonlinear Schrodinger (HNLS) equation describing propagation of femtosecond light pulses in an optical fiber under certain parametric conditions. Unlike the reported solitary wave solutions of the HNLS equation, the novel ones can describe bright and dark solitary wave properties in the same expressions and their amplitude may approach nonzero when the time variable approaches infinity. In addition, such solutions cannot exist in the nonlinear Schrodinger equation. Furthermore, we investigate the stability of these solitary waves under some initial pertubations by employing the numerical simulation methods.

[Analyzing study of complications of tissue expansion related to the injectable system]

OBJECTIVE

To analyze the complications of tissue expansion related to its injectable system.

METHODS

One hundred and ninety six patients were followed up and analyzed for the complications of the tissue expansion concerned to its injectable system. The management of these complications was also reviewed.

RESULTS

There were five kinds of the complications(with the occurrence of 32%) related to the injectable system in this group patients. The highest frequency of the complications occurred in the implantation stage. Further management was also documented well.

CONCLUSION

The complications of tissue expansion related to the injectable system occurred commonly and should be paid more attention on them.

Ligand-induced stabilization of PPARgamma monitored by NMR spectroscopy: implications for nuclear receptor activation

Nuclear receptors are ligand-dependent transcription factors that are mediators of the action of lipophilic hormones and other endogenous ligands and are the targets of drugs useful in a variety of therapeutic areas. Peroxisome proliferator-activated receptor (PPAR)gamma is a nuclear receptor that, acting as a heterodimer with RXR, mediates a variety of cellular effects including adipocyte-differentiation. Due to its role in modulating insulin sensitivity, it is the target of therapeutically active anti-diabetic agents such as rosiglitazone. We have assigned the chemical shifts of the backbone atoms of the 32 kDa ligand-binding domain of PPARgamma in the presence of bound rosiglitazone. Three-dimensional HNCO spectra of the apo ligand-binding domain (LBD) have less than half the expected number of cross-peaks. The missing cross-peaks are restored upon binding strong agonists such as rosiglitazone. The NMR results indicate that the apo-LBD of PPARgamma is in a conformationally mobile state, and that agonist binding is associated with a marked stabilization of the conformation. Mapping the missing peaks to the 3D X-ray crystallographic structure indicates the region of mobility is extensive and includes the ligand-binding region and the cofactor-binding site. This leads to the conclusion that activation of this nuclear receptor is a result of a population shift of a dynamic ensemble of conformations, rather than a two-state switch from an inactive to an active conformation. Our results have important implications for the mechanisms by which antagonists, partial agonists, and agonists of nuclear receptor function operate.

[Subcutaneous panniculitis-like T-cell lymphoma: expression of cytotoxic-granule-associated protein TIA-1 and its relation with Epstein-Barr virus infection]

OBJECTIVE

To study the clinicopathologic features, the expression of cytotoxic-granule-associated protein TIA-1 and Epstein-Barr virus (EBV) infection in subcutaneous panniculitis-like T-cell lymphoma (SPTCL).

METHODS

Totally 17 cases of SPTCL were studied. Immunohistochemical staining was done for TIA-1, CD45RO, CD3, CD20 and CD68, and in situ hybridization for EBV encoded small nuclear RNA (EBER1/2).

RESULTS

In the 17 cases of SPTCL, the ratio of male-to-female was 1:1.1 and the median age was 24 years old. The main clinical manifestations were asymptomatic plaques, nodules and masses. Histologically, the pattern of lymphoid cells infiltration was panniculitis. The infiltrated lymphoid cells were pleomorphic and their mitotic figures were few (0 - 2/hpt). In the tumor tissue, there might be epithilioid granulomas, multinuclear cells, beanbag cells, small pieces of necrosis and small vessels with lymphoid cells infiltration in the vascular wall. Immunohistochemically, all the cases showed a T-cell phenotype and the expression rate of TIA-1 was 100% (16/16). By in situ hybridization, the positive rate of EBV-EBER1/2 was 29.4% (5/17).

CONCLUSIONS

SPTCL has a specific histopathologic picture. It may originate from cytotoxic T lymphocytes or NK cells. Some of them may be accompanying with EBV latent infection.

Transforming and carcinogenic potential of cadmium chloride in BALB/c-3T3 cells

A large number of workers are potentially exposed to cadmium during mining and processing. Therefore, there is a concern regarding the potential carcinogenic hazards of cadmium to exposed workers. Studies have been performed to determine if cadmium chloride (CdCl(2)) can induce morphological cell transformation, DNA from CdCl(2)-induced transformed cells can transform other mammalian cells, and the transformed cells induced by CdCl(2) can form tumors in nude mice. BALB/c-3T3 cells were treated with different concentrations of CdCl(2) for 72 h. The frequency of transformed foci from each treatment was determined after cells were cultured for 4 to 5 weeks. DNAs from five CdCl(2)-induced transformed cell lines were isolated and gene transfection assay was performed using NIH-3T3 cells. Non-transformed BALB/c-3T3 cells and cells from 10 transformed cell lines induced by CdCl(2) were injected into both axillary regions of nude mice. Mice were screened once a week for the appearance and size of tumors. CdCl(2) caused a statistically significant, concentration-related increase in the transformation frequency. DNA from all five CdCl(2)-induced transformed cell lines tested was found to induce varying degrees of transfection-mediated transformation in NIH-3T3 cells. All 10 CdCl(2)-induced transformed cell lines formed fibrosarcomas in nude mice within 39 days of inoculation. Within this time period, no tumors were found in nude mice injected with non-transformed BALB/c-3T3 cells. These results indicate that CdCl(2) is capable of inducing morphological cell transformation and that the transformed cells induced by CdCl(2) are potentially tumorigenic.