[Clinical efficacy of antibiotic bone cement combined with vacuum sealing drainage in treating diabetes mellitus complicated with necrotizing fasciitis]

Objective: To explore the clinical efficacy of antibiotic bone cement combined with vacuum sealing drainage (VSD) in treating diabetes mellitus complicated with necrotizing fasciitis. Methods: The retrospective observational study approach was used. From January 2020 to March 2022, 12 patients with type 2 diabetes complicated with necrotizing fasciitis who met the inclusion criteria were admitted to Wuxi Ninth People's Hospital, including 7 males and 5 females, aged 27 to 76 years. The initial diagnosis of lesions was in the lower limbs. After admission, bedside incision and drainage were performed timely, and a sample of wound exudate was collected for microbial cultivation. At the same time, the comprehensive supportive treatment was performed. At stage Ⅰ, debridement was performed, and the skin and soft tissue defect area was 40 cm×15 cm to 80 cm×25 cm after debridement. The dead space was filled with bone cement containing gentamicin and vancomycin and VSD was performed. After there was no obvious infection on the wound, the antibiotic bone cement was removed and wound repair surgery was performed at stage Ⅱ. The times of debridement, amputation, infection control, wound treatment method and wound healing at stage Ⅱ, total hospitalization day, and recurrence of necrotizing fasciitis during follow-up after the stage Ⅱ surgery. At the last follow-up, the walking function of patients was evaluated according to the scoring standards of American Orthopedic Foot and Ankle Association (AOFAS). Results: Eleven patients had wound infection control with one debridement surgery and did not undergo amputation surgery; one patient had significant foot gangrene, and the infection was controlled after one debridement and amputation of the gangrenous limb. Blood routine and infection indicators gradually returned to normal within 7 days after surgery. At stage Ⅱ, the wounds in 4 patients were sutured directly, the wounds in 6 patients were repaired with full-thickness inguinal skin graft, while the wounds in 2 patients were repaired with pedicled or tongue-shaped flaps at the wound edge. The wounds healed well after surgery, with no ulceration. The total hospitalization day of patients was 20 to 45 days. Follow-up for 3 to 24 months after stage Ⅱ surgery showed no recurrence of necrotizing fasciitis in any patient. At the last follow-up, the walking function was evaluated as excellent in 10 cases and good in 2 cases according to the AOFAS scoring standard. Conclusions: Antibiotic bone cement combined with VSD used in treating type 2 diabetes complicated with necrotizing fasciitis can effectively control infection and reduce the times of debridement, with good wound healing and walking function after surgery.

[Effects of pedicled flap combined with membrane induction technique in repairing foot and ankle wounds in diabetic patients]

Objective: To explore the effects of pedicled flap combined with membrane induction technique in repairing foot and ankle wounds in diabetic patients. Methods: A retrospective observational study was conducted. From March 2019 to July 2021, 12 patients with diabetic foot and ankle wounds who met the inclusion criteria were admitted to Wuxi Ninth People's Hospital, including 7 males and 5 females, aged 20 to 92 years. The wound area before debridement was 4.0 cm×2.5 cm to 16.0 cm×12.5 cm. The patients underwent debridement+antibiotic cement tamponade in stage Ⅰ; according to the wound site, peroneal artery perforator flap or posterior tibial artery perforator flap was chosen to repair the wound in stage Ⅱ, with the area of the resected flap ranging from 4.5 cm×3.0 cm to 18.5 cm×14.0 cm. The donor site was directly closed in 4 patients or covered by full-thickness inguinal skin graft in 8 patients. After the operation of stage Ⅱ, the survival of flap and skin graft, the scar in donor and recipient sites of flap, the appearance of flap, and the function of ankle joint of affected extremity were followed up. The recovery of foot and ankle function was evaluated and rated by the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scoring System at the last follow-up. Results: During the follow-up of 4 to 15 months after the operation of stage Ⅱ, both the flap and skin graft survived, without obvious infection recurrence. Linear scars were left in donor and recipient sites of flap, with good appearance in flap. The function of ankle joint in the affected extremity was nearly normal. At the last follow-up, the AOFAS scores of patients were 79 to 93, with excellent in 8 cases and good in 4 cases. Conclusions: The pedicled flap combined with membrane induction technique for repairing foot and ankle wounds in diabetic patients has the advantage of simple operation, preserved ankle joint function, and less postoperative infection recurrence, which is worth popularizing in clinical practice.

Cytotoxicity and genotoxicity in liver cells induced by cobalt nanoparticles and ions

Objectives

The cytotoxicity induced by cobalt ions (Co²⁺) and cobalt nanoparticles (Co-NPs) which released following the insertion of a total hip prosthesis, has been reported. However, little is known about the underlying mechanisms. In this study, we investigate the toxic effect of Co²⁺ and Co-NPs on liver cells, and explain further the potential mechanisms.

Methods

Co-NPs were characterised for size, shape, elemental analysis, and hydrodynamic diameter, and were assessed by Transmission Electron Microscope, Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy and Dynamic Light Scattering. BRL-3A cells were used in this study. Cytotoxicity was evaluated by MTT and lactate dehydrogenase release assay. In order to clarify the potential mechanisms, reactive oxygen species, Bax/Bcl-2 mRNA expression, IL-8 mRNA expression and DNA damage were assessed on BRL-3A cells after Co²⁺ or Co-NPs treatment.

Results

Results showed cytotoxic effects of Co²⁺ and Co-NPs were dependent upon time and dosage, and the cytotoxicity of Co-NPs was greater than that of Co²⁺. In addition, Co-NPs elicited a significant (p < 0.05) reduction in cell viability with a concomitant increase in lactic dehydrogenase release, reactive oxygen species generation, IL-8 mRNA expression, Bax/Bcl-2 mRNA expression and DNA damage after 24 hours of exposure.

Conclusion

Co-NPs induced greater cytotoxicity and genotoxicity in BRL-3A cells than Co²⁺. Cell membrane damage, oxidative stress, immune inflammation and DNA damage may play an important role in the effects of Co-NPs on liver cells.

Cite this article: Y. K. Liu, X. X. Deng, H.L. Yang. Cytotoxicity and genotoxicity in liver cells induced by cobalt nanoparticles and ions. Bone Joint Res 2016;5:461–469. DOI: 10.1302/2046-3758.510.BJR-2016-0016.R1.

A case-control study indicates that the TRIB1 gene is associated with pancreatic cancer

Pancreatic cancer is a malignant neoplasm originating from transformed cells arising in tissues that form the pancreas. To investigate whether the tribbles homolog 1 (Drosophila) gene (TRIB1) is associated with pancreatic cancer in the Chinese Han population, we conducted this case-control study and genotyped 3 single nucleotide polymorphisms (rs2980879, rs2980874, and rs2235108) of the TRIB1 gene in 182 patients and 359 normal controls of Chinese Han origin and analyzed their association. The results showed that the rs2980879 polymorphism was associated with pancreatic cancer [allele: P = 0.023434, genotype: P = 0.03005; odds ratio (OR) and 95% confidence interval (CI) = 0.727788 (0.552664-0.958404)], whereas the rs2980874 polymorphism had no association with pancreatic cancer [allele: P = 0.749885, genotype: P = 0.699533; OR and 95%CI = 1.041981 (0.809196-1.341734)], and the rs2235108 polymorphism was not associated with the disease [allele: P = 0.629475, genotype: P = 0.547534, OR and 95%CI = 1.128290 (0.690829-1.842770)]. Haplotype analyses and linkage disequilibrium tests were also conducted, and the results showed that these 3 loci are not in the same block. In conclusion, our study indicated that the TRIB1 gene is associated with pancreatic cancer. More studies with larger samples are needed in order to support this finding.

Peripheral blood mRNA expression patterns to differentiate hepatocellular carcinoma from other hepatic diseases

Peripheral blood genes expressions profiling (GeXP) have been convinced to be more specific for the diagnosis of cancer and other diseases, and the GeXP system provides an ideal method to analyze multiple genes expression in one normalized and equable system. We aim to differentiate hepatocellular carcinoma from other hepatic diseases based on peripheral blood and the GeXP system. Fifteen selected hepatic diseases related genes with two house-keeping genes for normalization were detected by the GeXP system. The diagnosis model was based on K nearest neighbor classifier and cross validation, and software based on MATLAB software was built for differential diagnosis of hepatic diseases. Eight hepatic related genes were demonstrated to show an obvious statistic difference in expressions while the K nearest neighbors classifier showed that the accuracy for normal controls, hepatitis B, liver cirrhosis, hepatocellular carcinoma and the Other group was separately 80.57 %, 78.17 %, 84.48 %, 73.24 % and 85.85 %. The set of validation has been carried out to assess the accuracy of Model Two and the accuracy was even higher than the set of building for the model, except for the hepatitis B (HBV) group. A sensitive and specific GeXP system of eight genes has been developed for the accurate differential diagnosis of hepatic disease.

Peripheral blood mRNA expression patterns to differentiate hepatocellular carcinoma from other hepatic diseases

Peripheral blood genes expressions profiling (GeXP) have been convinced to be more specific for the diagnosis of cancer and other diseases, and the GeXP system provides an ideal method to analyze multiple genes expression in one normalized and equable system. We aim to differentiate hepatocellular carcinoma from other hepatic diseases based on peripheral blood and the GeXP system. Fifteen selected hepatic diseases related genes with two house-keeping genes for normalization were detected by the GeXP system. The diagnosis model was based on K nearest neighbor classifier and cross validation, and software based on MATLAB software was built for differential diagnosis of hepatic diseases. Eight hepatic related genes were demonstrated to show an obvious statistic difference in expressions while the K nearest neighbors classifier showed that the accuracy for normal controls, hepatitis B, liver cirrhosis, hepatocellular carcinoma and the Other group was separately 80.57 %, 78.17 %, 84.48 %, 73.24 % and 85.85 %. The set of validation has been carried out to assess the accuracy of Model Two and the accuracy was even higher than the set of building for the model, except for the hepatitis B (HBV) group. A sensitive and specific GeXP system of eight genes has been developed for the accurate differential diagnosis of hepatic disease.

Isolation of cytoplasts from Satsuma mandarin (Citrus unshiu Marc.) and production of alloplasmic hybrid calluses via cytoplast-protoplast fusion

Cytoplasm of Satsuma mandarin (Citrus unshiu Marc.) is known to influence seedlessness. Transfer of cytoplasm to a seedy cultivar could possibly lead to the production of seedless citrus fruits. In the present paper cytoplasts were isolated from cell suspension-derived protoplasts of Satsuma mandarin via ultra-centrifugation in a discontinuous gradient. No nucleus could be detected in the cytoplasts by DAPI (4', 6-diamidino-2-phenylindole) staining compared with normal protoplasts. The cytoplasts, with high viability and small size, did not divide during solid embedding culture. Cytoplasts of Satsuma mandarin were electrically fused with embryogenic protoplasts of Murcott tangor (C. reticulata x C. sinensis), which led to regeneration of several cell lines. Flow cytometry (FCM) indicated that the cell lines were diploids. Simple sequence repeats (SSR) and cleaved amplified polymorphism sequence (CAPS) showed that the cell lines got their nuclear DNA from the protoplast parent, whereas the cytoplast parent donated the mtDNA, confirming transfer of mtDNA from Satsuma mandarin into Murcott tangor via cytoplast-protoplast fusion though no polymorphism was detected in chloroplast DNA between the fusion partners. This is the first report on isolation and characterization of cytoplasts, together with cytoplast-protoplast fusion in Citrus, which has a potential for citrus cultivar improvement involving cytoplasm transfer via cytoplast-protoplast fusion.

GISH, AFLP and PCR-RFLP analysis of an intergeneric somatic hybrid combining Goutou sour orange and Poncirus trifoliata

Intergeneric somatic hybrids combining Goutou sour orange (Citrus aurantium L.) with trifoliate orange Poncirus trifoliata (L.) Raf] were produced by electrofusion and their genetic inheritance analyzed by amplified fragment length polymorphism (AFLP), genomic in situ hybridization (GISH), and PCR-restriction fragment length polymorphism (PCR-RFLP). Sixteen mini-calluses were obtained after 20 days of culture; they all developed into embryoids on EME500 medium. Following several subcultures on shoot induction medium for a total culture period of 6 months, shoots regenerated. The plants grew vigorously with a well-developed root system and exhibited the trifoliate leaf character of P. trifoliata. Ploidy analysis verified that all of the regenerates were tetraploids (2 n=4 x=36) as expected. GISH analysis confirmed that 18 chromosomes came from trifoliate orange and the remaining 18 from Goutou sour orange, as with most symmetric somatic hybrid plants; moreover, chromosome translocations were also observed in one plant. AFLP analysis of 16 regenerates and their fusion parents indicated that all of the somatic hybrids except one were genetically uniform. Analysis of the somatic hybrid cytoplasmic genomes with universal primers revealed that their chloroplast DNA (cpDNA) banding patterns were identical to those of the mesophyll parent trifoliate orange, while their mitochondria (mt) genomes were of the callus parent sour orange. The potential of GISH in Citrus somatic hybrid analysis is discussed.

Targeted cybridization in citrus: transfer of Satsuma cytoplasm to seedy cultivars for potential seedlessness

CMS (cytoplasmic male sterility) can be controlled by the mitochondrion genome in higher plants, including Satsuma mandarin. Somatic fusion experiments in citrus combining embryogenic callus protoplasts of one parent with leaf protoplasts of a second parent often produce cybrid plants of the leaf parent, a phenomenon occurring most often with interspecific fusion combinations. In an attempt to practically exploit this cybridization phenomenon, we conducted somatic fusion experiments combining embryogenic suspension-derived protoplasts of Satsuma mandarin, Citrus unshiu Marc. cv. Guoqing No. 1 (G1), a male-sterile cultivar, with leaf protoplasts of other seedy types--Hirado Buntan Pink pummelo (HBP) [Citrus grandis (L.) Osbeck], Sunburst mandarin (C. reticulata Blanco), Orie Lee hybrid (C. reticulata cv. Clementine x Murcott tangor), and Murcott tangor [C. reticulata x C. sinensis (L.) Osbeck], respectively--in an attempt to generate seedless cybrids by the targeted transfer of CMS. The genetic identities of regenerated plants from all four parental combinations were determined by flow cytometry, SSR, CAPS (or PCR-RFLP), RFLP, and chloroplast-SSR analyses. Regenerated plants from the first three parental combinations were diploids, and the cybrid nature of G1 + HBP with the mitochondrion genome from G1 and the chloroplast genome from HBP was confirmed, whereas the cybrid nature of the remaining two combinations was difficult to confirm because of the close phylogenetic relatedness of both fusion parents, as expected. Plants from G1 + Murcott were confirmed as tetraploid somatic hybrids. This is the first report of targeted citrus cybrid production by symmetric fusion with male-sterile Satsuma as the callus parent and other seedy cultivars as the leaf parents.

Factors influencing Agrobacterium-mediated embryogenic callus transformation of Valencia sweet orange (Citrus sinensis) containing the pTA29-barnase gene

Valencia sweet orange (Citrus sinensis (L.) Osbeck) calluses were used as explants to develop a new transformation system for citrus mediated by Agrobacterium tumefaciens. Factors affecting Agrobacterium-mediated transformation efficiency included mode of pre-cultivation, temperature of cocultivation and presence of acetosyringone (AS). The highest transformation efficiency was obtained with a 4-day pre-cultivation period in liquid medium. Transformation efficiency was higher when cocultivation was performed for 3 days at 19 degrees C than at 23 or 28 degrees C. Almost no resistant callus was obtained if the cocultivation medium lacked AS. The transformation procedure yielded transgenic Valencia plants containing the pTA29-barnase gene, as verified by PCR amplification and confirmed by Southern blotting. Because male sterility is a common factor leading to seedlessness in citrus cultivars with parthenocarpic characteristics, production of seedless citrus genotypes by Agrobacterium-mediated genetic transformation is a promising alternative to conventional breeding methods.

Molecular characterization of cytoplasmic and nuclear genomes in phenotypically abnormal Valencia orange (Citrus sinensis) + Meiwa kumquat (Fortunella crassifolia) intergeneric somatic hybrids

Organelle DNA inheritance of four 10-year-old somatic hybrid trees between Valencia orange [Citrus sinensis (L.) Osbeck] and Meiwa kumquat (Fortunella crassifolia Swingle) was analyzed by cleaved amplified polymorphic sequence (CAPS) and restriction fragment length polymorphisms (RFLPs). Five chloroplast (cp) and three mitochondrial (mt) universal primer pairs were amplified, but no polymorphisms were detected. When the polymerase chain reaction products were digested by 15 restriction enzymes, four polymorphic cpDNA-CAPS and two mtDNA-CAPS markers were found. Both the cpDNA and mtDNA in the somatic hybrids were derived from Valencia orange (the embryogenic suspension parent). Genomic DNA of the somatic hybrids and corresponding parents was digested by five restriction endonucleases and hybridized with one chloroplast probe (RbcL- RbcL) and nine mitochondrial probes (coxI, coxII, c oxIII, c ob, atpA, tyr, proI, atp6 and atp9). The results indicated that three hybrid plants shared one strong cpDNA band with both parents and that the remaining one plant had two additional novel bands besides the shared band, while their mtDNA was identical to that of Valencia orange plus non-parental bands. When data on the mtDNA banding patterns were combined with observations on phenotypic performance in the field, it was found that the more complex mtDNA banding pattern coincided with increased vigor of the plant. The stability of the organelle genomes was studied by extracting the genomic DNA of one hybrid plant at monthly intervals for 1 year and then analyzing it using RFLPs. Before the dieback of the shoots, two fragments of the mtDNA were lost while the cpDNAs remained stable. Ploidy analysis by flow cytometry showed that all of the hybrids were stable tetraploids. Four simple sequence repeat primer pairs were applied to detect microsatellite alleles of the four hybrid plants, both parents and the 12 DNA samples from one plant. The results showed that all hybrids had biparental bands uniformly, which indicated that they had the same nuclear background. These results suggest that the mtDNA pattern is correlated with the phenotypic abnormality of Valencia and kumquat somatic hybrid plants and that nuclear-cytoplasm incompatibility may be the cause of dieback.

Effect of cryopreservation on apple genetic resources at morphological, chromosomal, and molecular levels

Shoot tips of three apple genotypes, namely, Malus pumila cv. M26, Gala, and Hokkaido No. 9, were successfully cryopreserved using a modified encapsulation-dehydration method. As a result, in addition to a high survival rate and regeneration rate, the capacity of shoots regenerated from cryopreserved samples to root was enhanced. Eight M26 single-bud sibling lines were used to assess genetic stability. Although cytological examination revealed a ploidy difference in the noncryopreserved control, the ploidy constitution remained relatively stable during the period of cryopreservation. Amplified fragment length polymorphism (AFLP) assay was performed to detect DNA-level variation. No change in DNA fragment pattern and number was observed between the control and the cryopreserved samples. In addition, methylation-sensitive amplified polymorphism (MSAP) assay was carried out to investigate the DNA methylation status during the period of cryopreservation. It was found that cryopreservation induced a decrease in DNA methylation level.

[Production of intergeneric somatic hybrid plants via protoplast electrofusion in citrus]

Leaf derived protoplasts of Sour orange (Citrus aurantium L.) were fused electrically with embryogenic protoplasts of Microcitrus papuana Swingle. Plants were regenerated from the fusion products, which were characteristic with three types of leaf morphology. Most of the plants were identical to Sour orange (namely, Leaf-parent-type plant) and two plants had large and thick leaves whereas one plant had bifoliate and trifoliate leaves. Chromosome examination showed that these plants were diploid with 18 chromosomes (2n = 2x = 18). RAPD analysis was employed to verify the hybrid characteristics of the plants in the first two types. Four 10-mer arbitrary primers with polymorphism were chosen. Band pattern of the plants was similar with the leaf parent (Sour orange) for the primer OPAA-17. Band pattern of the plants was similar with either Sour orange or M. papuana for OPA-08. As for OPA-07 and OPA-04 three kinds of band profiles were detected. Results of RAPD marker, together with chromosome determination, indicated that all of the analyzed plants were intergeneric diploid somatic hybrids between Sour orange and M. papuana.

[Two interspecific somatic hybrid plants regenerated via protoplast electro-fusion]

Protoplasts isolated from cell suspension cultures of 'Bonnaza' navel orange (Citrus sinensis L. Osbeck) were electrically fused with mesophyll protoplasts of rough lemon (Citrus jambhiri Lush) and Goutou orange (Citrus aurantium L.) respectively. Plants regenerated from both fusion combinations. Chromosome counting of randomly selected fifty two globular embryoids as well as all the regenerated seventy four plants from Bonnaza navel + rough lemon revealed that twenty six embryoids were tetraploids, and the rest were diploids while 100% regenerated plants were tetraploids. The results inferred that somatic hybrids were more competitive than parental genotypes in the process of plant regeneration. All the regenerated 14 plants from Bonnaza navel + Goutou orange were tetraploids as revealed by chromosome counting. POX isozyme and RAPD analysis verified that the plants from Bonnaza navel + rough lemon were hybrids, and RAPD analysis confirmed the hybridity of those from Bonnaza navel + Goutou orange.

[Genetic analysis of leaf-parent-type plants regenerated from somatic hybridization in Citrus]

The leaf indexes and stoma characteristics of leaf-parent-type regenerants were the same as those of the leaf parent Rough lemon, but quite different from the somatic hybrids. Leaf-parent-type plants were diploid (2n = 2x = 18). Patterns of POX, PPO, GOT isozymes were identical to those of Rough lemon. The plants were analyzed by using 54 arbitrary primers with polymorphisms. Most of the primers (52) showed that leaf-parent-type plants were in concordance with Rough lemon. However, with primer OPW-12, the plants contained a unique band of Hamlin sweet orange. Amplification products with primer OPV-04 showed slight differences among the accessions. The research suggested that most genetic constitutions of the leaf-parent-type plants were from leaf parent Rough lemon and a little from embryogenic suspension parent Hamlin sweet orange.

[Induction of embryogenic callus of loose skin mandarins]

Young ovules from 3 cultivars and undeveloped ovules in mature fruits from 8 cultivars of loose skin mandarin of Citrus were cultured on 4 different media respectively to induce embryogenic calli. Results showed that the combination of EME(MT + 500 mg/L malt extract) and MKT (EME + 10 mg/L KT) media performed well in the induction of embryogenic calli from young ovules; MGS(EME + 1 mg/L GA3 + 40 mg/L sulfate adenine) medium was better than MDB (MT + 0.01 mg/L 2,4-D + 0.1 mg/L BA) medium in inducing calli from the undeveloped ovules, and the darkness was conducive to the induction of embryogenic calli. There was no chromosome number variation in the induced calli. All of the examined cells were diploid with 2n = 2x = 18 chromosomes.

Effect of metformin on patients with impaired glucose tolerance

AIMS

To evaluate the effect of metformin on glucose metabolism, insulin sensitivity and rate of conversion diabetes in people with impaired glucose tolerance (IGT).

METHODS

Seventy subjects with IGT were randomized under double-blind conditions to receive either placebo (n = 37) or metformin (n = 33) at a dosage of 250 mg three times daily for a duration of 12 months. Glycaemic control, plasma insulin and other biochemical indexes were assessed before and after 3, 6 and 12 months.

RESULT

At 12 months the conversion rate to diabetes was 16.2% in the placebo group compared to 3.0% for the metformin group (P = 0.011). Of subjects treated with metformin for 12 months, 84.9% became normoglycaemic compared to 51.4% of those receiving the placebo. Significant improvements in fasting glucose, glucose tolerance and insulin sensitivity were found at 12 months and at intermediate clinic assessments.

CONCLUSIONS

Metformin can improve glucose metabolism in IGT patients and may be a treatment option in their management of IGT subjects.

Somatic hybrid plantlets regeneration between Citrus and its wild relative, Murraya paniculata via protoplast electrofusion

Protoplasts isolated from `Page' tangelo (Minneola tangelo × clementine) cell suspension cultures were electrically fused with mesophyll protoplasts of orange jessamine [Murraya paniculata (L.) Jack]. Shoots were regenerated after 6 - 10 months of culture, but they were extremely recalcitrant to producing roots in root-induction medium. Complete plantlets were formed via micrografting. Chromosome counting of shoot tips revealed they were tetraploids (2n = 4x = 36). Glutamateoxaloacetate transaminase isozyme and randomly amplified polymorphic DNA analysis confirmed their hybridity. Orange jessamine is immune to citrus huanglongbin, a severe disease of citrus, but sexual incompatibility and limited graft compatibility exist between Citrus and orange jessamine. The cell fusion technique may make it possible to transfer the huanglongbin resistance trait from orange jessamine to Citrus.

[Observation of female gametophyte development of Ginkgo biloba and its protoplast isolation and culture]

Results of observation showed that the female gametophyte of Ginkgo biloba was at the coenocytic stage from March 30ty to May 30ty. A density of 6-8 x 10(5) protoplasts/ml with a viability of 87.3% was achieved when the female gametopytes collected from May 8th to 15th were treated with 0.5% cellulase Onzuka R-10, 0.5% Pectolyase for 4-5 hours. The thin-layer liquid Murashige and Tuker medium modified by omitting ammonium ions and supplementing with glutamine 1000 mg/L, Vc 5 mg/L, benzyladenine 1.0 mg/L and naphthaleneacetic acid 3.0 mg/L was used for the protoplast culture and multiple cell colonies were obtained.

Study of the prevalence of diabetes mellitus in adults in the Shougang Corporation in Beijing

The aim was to determine the burden of diabetes mellitus (DM) in an urban area of China to aid us in planning preventive measures for those at risk of DM. A survey was conducted among the 29,859 subjects aged between 30 and 64 belonging to 32 units of the Shougang Corporation (a heavy industry enterprise) within the Beijing area. WHO study protocols and diagnostic criteria were used to determine the prevalence of DM and impaired glucose tolerance (IGT). The results showed that the age-adjusted prevalence of DM and impaired glucose tolerance (IGT) was 3.63% and 4.19%, respectively, both increasing with age. Peak prevalence for both occurred in the 60-64 age group. Prevalence showed no difference between the sexes in DM but was higher for females in IGT. Obesity, being overweight, a family history of diabetes mellitus and in women, a history of delivering babies with macrosomia, all correlated closely with the prevalence of DM and IGT. High protein intake was also associated with DM, Smoking had no effect on either DM or IGT. Intellectual workers had a higher incidence of IGT than manual workers. Seventy per cent DM was undiagnosed prior to the survey. This survey, done according to the recommendation of WHO, and including appropriate adjustments, reflects the growing prevalence of DM and IGT in this population. It can be compared with other studies for epidemiological analysis.

[Effect of hypoxia on the conversion of angiotensin I to A II in pulmonary vascular endothelial cells]

The effect of hypoxia on intrapulmonary conversion of angiotensin I (A I) to angiotensin II (A II) was examined by using an isolated rat lung preparation perfused at constant flow and cultured calf pulmonary artery endothelial cells. The conversion rate of A I in endothelial cells of pulmonary vascular bed was found to be decreased in both acute hypoxic and chronic hypoxic (CH-5000, CH-8000) rats. The conversion rate of A I to A II was significantly higher in acute hypoxic rat lungs than that in denuded endothelial cells rat lungs. There was no significant difference between chronic hypoxic and denuded endothelial cells rat lungs. In cultured calf pulmonary artery endothelial cells (PAEC) exposed to hypoxia (3% O2) for 30 minutes the conversion of A I to A II was significantly reduced. In the time course of hypoxic exposure the conversion of A I to A II in cultured calf PAEC showed significant difference between hypoxia and normoxia. The results indicated that (1) Acute and chronic hypoxia impaired pulmonary conversion of A I to A II. (2) Effect of hypoxia on the pulmonary conversion of A I to A II is associated with the degree and the time of hypoxia.

[Role of endothelium-derived relaxing factor in the contractions of intrapulmonary artery induced by oxygen-derived free radicals in chronic hypoxic rat]

The role of endothelium-derived relaxing factor (EDRF) on the effect of oxygen-derived free radicals (generated by xanthine-xanthine oxidase system) on intrapulmonary arterial in chronic hypoxic rats was studied by a microbioassay method. Intrapulmonary artery rings with intact or denuded endothelium of hypoxic (5,000 m, 10 days) and normoxic rats were prepared for observation of oxygen-derived free radicals induced contraction. It was shown that oxygen-derived free radicals induced contractions of intrapulmonary arterial rings with intact endothelium were obviously augmented in hypoxic rats than in normoxic controls. The augmented responses could be further potentiated by the addition of EDRF inactivator reduced hemoglobin (RHb), but diminished or even abolished by applying superoxide dismutase (Cu-Zn SOD). However, no effect on denuded rings was observed when RHb or SOD was added. It is concluded that chronic hypoxia may attenuate the action of EDRF in the enhancement of the reactivity of intrapulmonary artery to oxygen-derived free radicals.

Genetic transformation of xylose-fermenting yeast Pichia stipitis. Scientific note

A plasmid-mediated transformation system has been developed for the xylose-fermenting yeast Pichia stipitis. We found that plasmid vectors containing the Saccharomyces cerevisiae 2 mu replicon and the kanamycin resistance gene (KmR) could be introduced into the Pichia cells and maintained as extrachromosomal elements. Pichia transformants containing such vectors will be resistant to the antibiotic geneticin that can be inactivated by the protein product of KmR. Plasmids identical to those used for transformation can be recovered from the Pichia transformants. Protocols for transformation of P. stipitis by the CaCl2-polyethylene glycol-protoplast process or by direct electroporation of intact Pichia cells have both been developed.

Induction of triploid Citrus plants from endosperm calli in vitro

Triploid hybrid Citrus plants were regenerated by somatic embryogenesis in vitro from endosperm derived calli. A sequence of media formulations was used to induce and support proliferation of primary callus from endosperm, to induce embryogenesis from primary callus, and to allow embryo development leading to viable plantlets. Calli were induced from cellular endosperm of Citrus sinensis (sweet orange), C. Xparadisi (grapefruit), and C. grandis (pummelo) excised 12-14 weeks post-anthesis. Induction of embryogenesis from sweet orange and pummelo primary calli required gibberellic acid and double mineral nutrient concentrations. Embryogenesis was not induced from grapefruit calli in these experiments. Only sweet orange embryos developed sufficiently to allow plant regeneration. Triploid axillary buds were minigrafted onto etiolated diploid rootstock seedlings in vitro in order to transfer triploid regenerants to soil and the external environment. Triploidy (2n = 3x = 27) was observed consistently in all phases of regeneration and in recovered plants. These results demonstrate that triploid hybrid plant recovery from Citrus endosperm can overcome barriers to sexual hybridization resulting from apomixis.

Xylulokinase activity in various yeasts including Saccharomyces cerevisiae containing the cloned xylulokinase gene. Scientific note

D-Xylose is a major constituent of hemicellulose, which makes up 20-30% of renewable biomass in nature. D-Xylose can be fermented by most yeasts, including Saccharomyces cerevisiae, by a two-stage process. In this process, xylose is first converted to xylulose in vitro by the enzyme xylose (glucose) isomerase, and the latter sugar is then fermented by yeast to ethanol. With the availability of an inexpensive source of xylose isomerase produced by recombinant E. coli, this process of fermenting xylose to ethanol can become quite effective. In this paper, we report that yeast xylose and xylulose fermentation can be further improved by cloning and overexpression of the xylulokinase gene. For instance, the level of xylulokinase activity in S. cerevisiae can be increased 230fold by cloning its xylulokinase gene on a high copy-number plasmid, coupled with fusion of the gene with an effective promoter. The resulting genetically-engineered yeast can ferment xylose and xylulose more than twice as fast as the parent yeast.