Biological Properties of 3D-Printed Zirconia Implants with p-Cell Structures

Research on 3-dimensional (3D) printed porous zirconia-based dental implants is still in its infancy. This study aimed to evaluate the biological responses of novel zirconia implants with p-cell structures fabricated by 3D printing. The solid zirconia samples exhibited comparable density, 3-point flexural strength, and accelerated aging properties compared to specimens prepared previously by conventional methods. Cell-based experiments showed that the p-cell structure promoted cell proliferation, adhesion, and osteogenesis-related protein expression. Mechanical tests showed that both p-cell and control implants could withstand a torque of 35 Ncm without breaking. The mean maximum breaking loads of p-cell and control implants were 1,222.429 ± 115.591 N and 1,903.857 ± 250.673 N, respectively, which were much higher than the human physiological chewing force and human mean maximum occlusal force. An animal experiment showed that the bone trabeculae around the implants were significantly thicker, more numerous, and denser in the p-cell group than in the control group. This work could provide promising guidance for further exploring 3D printing techniques for porous zirconia bionic implants in dentistry.

Construction of carbon sequestration ecological network in Linyi City based on supply and demand of ecosystem service

The increasing carbon emissions is one of the important reasons for global warming. As a key area of carbon emissions, carbon sequestration capacity of cities is urgently needed to be improved. Carbon sequestration ser-vices can be transferred between supply and demand areas due to the circulation of atmosphere. With Linyi City as an example, we used the minimum cumulative resistance model to extract the matching path of supply and demand, and constructed a carbon sequestration ecological network. The results showed that the regions with high supply of carbon sequestration services were located in the north and south of the study area, and that current total supply could solve about 60% of the total demand. Although the spatial distribution of supply and demand was uneven, 54% of the areas that could meet the surrounding carbon sequestration demand were still idle. The optimized supply-demand matching paths could maintain good transmission efficiency of material and energy, with lower costs. Paths with strong potential carbon sequestration capacity were located in the central and northwest part of the research area. In the construction of carbon sequestration ecological network, it is necessary to strengthen the protection and restoration of the supply side of carbon sequestration services, realize carbon reduction and strengthen carbon sequestration on the demand side, and optimize the matching path of supply and demand. This method provided services to the demand areas through the oversupply of ecosystem services, optimized the overall resource allocation, which could advance regional carbon sequestration capacity.

Buschke-Ollendorff syndrome presenting with asymptomatic yellowish papules and leg length discrepancy: A case report

Buschke-Ollendorff syndrome (BOS) is a rare, usually benign, autosomal dominant genetic disease affecting about 0.005% globally. BOS commonly manifests with asymptomatic connective tissue nevi, sometimes with sclerotic bone lesions like osteopoikilosis or melorheostosis. However, BOS may develop severe, symptomatic complications that require surgical intervention. Here we report a 9-year-8-month girl presenting with multiple nonpruritic, nonpainful skin plaques scattered around the trunk, buttocks, and bilateral legs. She had a history of right varus foot with inadequate plantar flexion. Upon visiting, obvious leg length discrepancy (LLD) was noted. Lesional biopsy revealed increased fibroblasts within dermal collagen bundles. Verhoeff-van Gieson stain revealed scattered foci of thickened elastic fibers between collagen fibers, especially in the mid-dermis. Radiographic examination of the lower extremities showed multiple small, round-to-oval shaped, radiopaque spots on the pelvic bones, femurs, tibiae, and both feet. Hyperostosis along the long axis with "dripping candle wax" appearance was characteristic of osteopoikilosis and melorheostosis. Genetic analysis showed heterozygous point mutation in exon 1 of LEMD3 gene (c.1323C>A, p.Y441X), confirming diagnosis of BOS. Sequential and epiphyseodesis were performed to correct LLD with a favorable outcome at 2-year follow-up. BOS associated with severe bone abnormalities is rare, but orthopedic surgical intervention can provide satisfactory outcome.

Association of multiple sclerosis with vitiligo: a systematic review and meta-analysis

Polyautoimmunity implicates that some autoimmune diseases share common etiopathogenesis. Some studies have reported an association between multiple sclerosis (MS) and vitiligo; meanwhile, other studies have failed to confirm this association. We performed a systemic review and meta-analysis to examine the association of MS with vitiligo. We searched the MEDLINE and Embase databases on March 8, 2020 for relevant case–control, cross-sectional, and cohort studies. The Newcastle–Ottawa Scale was used to evaluate the risk of bias of the included studies. Where applicable, we performed a meta-analysis to calculate the pooled odds ratio (OR) for case–control/cross-sectional studies and risk ratio for cohort studies with 95% confidence interval (CI). Our search identified 285 citations after removing duplicates. Six case–control studies with 12,930 study subjects met our inclusion criteria. Our meta-analysis found no significant association of MS with prevalent vitiligo (pooled OR 1.33; 95% CI 0.80‒2.22). Analysis of the pooled data failed to display any increase of prevalent vitiligo in MS patients compared with controls. Ethnic and genetic factors may play an important role for sporadically observed associations between MS and vitiligo. Future studies of this association should therefore consider stratification by ethnic or genetic factors.

Toxic epidermal necrolysis induced by human herpesvirus 7 treated with a tumor necrosis factor-α inhibitor

Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is a life-threatening hypersensitivity reaction. Long-term sequelae include dry eyes, visual impairment and psychological complications. TEN is mostly induced by medication; however, viral infections, such as coxsackievirus A6, are known triggers of this disease. However, how to define the role of infection in SJS/TEN is still a problem. Most patients develop SJS/TEN over the course of symptoms of the infection first, and then take medication. Therefore, virus culture and nucleic acid detection at the acute stage cannot predict that the virus itself will indeed produce such a serious reaction. Furthermore, many SJS/TEN patients who are diagnosed with an infection are afraid of receiving the drug rechallenge test. Thus, we report the first case worldwide of a patient who suffered from TEN caused by herpesvirus 7 infection, which was confirmed by both real-time polymerase chain reaction and lymphocyte transformation test.

In vitro evaluation of the hyaluronic acid/alginate composite powder for topical haemostasis and wound healing

The use of haemostatic agents can provide life-saving treatment for patients who suffer from massive bleeding in both prehospital and intraoperative conditions. However, there are still urgent demands for novel haemostatic materials that exhibit better haemostatic activity, biocompatibility, and biodegradability than existing products. In the present study, we aim to evaluate the feasibility of new wound dressing, RapidClot, for treating uncontrolled haemorrhage through a series of in vitro assessments to determine the swelling ratio, clotting time, enzymatic degradation, haemolytic activity, cytotoxicity, cell proliferation, and migration. The results indicated that the RapidClot revealed better water adsorption capacity and shorter blood clotting time (132.7 seconds) than two commercially available haemostatic agents Celox (378.7 seconds) and WoundSeal (705.3 seconds). Additionally, the RapidClot dressing exhibited a similar level of degradability in the presence of hyaluronidase and lysozyme as that of Celox, whereas negligible degradation of WoundSeal was obtained. Although both Celox and RapidClot revealed a similar level in cell viability (above than 90%) against NIH/3 T3 fibroblasts, improved cell proliferation and migration could be obtained in RapidClot. Taking together, our results demonstrated that RapidClot could possess a great potential for serving as an efficient healing dressing with haemorrhage control ability.

[Quantitative study on the development of fetal ventricles and cisterna magna in second and third trimesters with MRI]

Objective: To analyze the changes of growth and development of normal fetal ventricles and cisterna magna with gestational age(GA) and the correlation with fetal gender in the second and third trimester,and establish the MR prenatal diagnosis reference standards. Methods: A total of 633 fetuses (mean GA (27.0±4.1) weeks (18.9-40.6 weeks))without central nervous system abnormalities were retrospectively collected from the Obstetrics and Gynecology Hospital of Fudan University from June 2012 to August 2017. The lateral ventricle trigonometric width (LVTW), third ventricle width (TVW), fourth ventricle width (FVW), anterior-posterior diameter of the fourth ventricle(APDFV), cavum septum pellucidum width (CSPW) and cisterna magna width (CMW) were obtained in the standard measure planes on MR image.The correlation between the biometrics and GA and the correlation between the biometrics and fetal gender were analyzed respectively, and the normal reference values of the biometrics were calculated. Spearman correlation analysis, Pearson correlation analysis,linear regression analysis, independent samples t-test and paired samples t-test were used for statistic analysis. Results: (1)Fetal LLVTW,RLVTW,TVW,CSPW and CMW in second and third trimesters were correlated with GA at medium and low levels(the correlation coefficient r were 0.311, 0.277, 0.207, 0.226, 0.295, respectively, all P<0.01). FVW and APDFV were statistically correlated with GA, and the linear regression equations were as follows: y=0.022×GA-0.043 (adjusted R(2)=0.642); y=0.018×GA-0.159 (adjusted R(2)=0.690). (2)Fetal LLVTW,RLVTW,FVW,APDFV and CSPW were not correlated with fetal gender in second and third trimesters(r=-0.078,-0.057,-0.087,-0.004 and 0.024, P=0.124,0.258,0.085,0.931 and 0.618, all P>0.05). TVW and CMW were statistically correlated with fetal gender(r=-0.310, -0.180, P=0.000, 0.006, all P<0.05). (3) The mean values of LLVTW and RLVTW were (0.71±0.13) cm and (0.68±0.13) cm, respectively, and significant difference was found between them(t=3.180, P=0.002). The mean value of CSPW was (0.59±0.15) cm. And the mean values of male and female fetuses for TVW and CMW were (0.17±0.05) cm, (0.16±0.06) cm and (0.68±0.15) cm, (0.58±0.15) cm, respectively. The corresponding prenatal MRI diagnostic criteria were as follows: LLVTW 1.1 cm, RLVTW 1.0 cm, CSPW 1.0 cm, TVW 0.3 cm, CMW (male 1.1 cm, female 1.0 cm). Conclusions: The normal fetal ventricles and cisterna magna are increased with the GA in the second and third trimesters. TVW and CMW are related to fetal gender. The establishment of normal reference values of fetal ventricles and cisterna magna based on GA and fetal gender are conducive to enhance the accuracy of MRI prenatal diagnosis.

mTORC1 drives HIF-1α and VEGF-A signalling via multiple mechanisms involving 4E-BP1, S6K1 and STAT3

Recent clinical trials using rapalogues in tuberous sclerosis complex (TSC) show regression in volume of typically vascularised tumours including angiomyolipomas (AMLs) and sub-ependymal giant cell astrocytomas (SEGAs). By blocking mechanistic/mammalian target of rapamycin complex 1 (mTORC1) signalling, rapalogue efficacy is likely to occur in part through suppression of hypoxia inducible factors (HIFs) and vascular endothelial growth factors (VEGFs). We show that rapamycin reduces HIF-1α protein levels, and to a lesser extent VEGF-A levels, in renal cystadenoma cells in a Tsc2+/− mouse model. We establish that mTORC1 drives HIF-1α protein accumulation through enhanced transcription of HIF-1α mRNA, a process that is blocked by either inhibition or knockdown of signal transducer and activation of transcription 3 (STAT3). Furthermore, we demonstrate that STAT3 is directly phosphorylated by mTORC1 on Ser727 during hypoxia, promoting HIF-1α mRNA transcription. mTORC1 also regulates HIF-1α synthesis on a translational level via co-operative regulation of both initiation factor 4E-binding protein 1 (4E-BP1) and ribosomal protein S6 kinase-1 (S6K1), whilst HIF-1α degradation remains unaffected. We therefore propose that mTORC1 drives HIF-1α synthesis in a multi-faceted manner through 4E-BP1/eIF4E, S6K1 and STAT3. Interestingly, we observe a disconnect between HIF-1α protein levels and VEGF-A expression. While both S6K1 and 4E-BP1 regulate HIF-1α translation, VEGF-A is primarily under the control of 4E-BP1/eIF4E. S6K1 inhibition reduces HIF-1α but not VEGF-A expression, suggesting that mTORC1 mediates VEGF-A expression via both HIF-1α-dependent and -independent mechanisms. Our work has important implications for the treatment of vascularised tumours, where mTORC1 acts as a central mediator of STAT3, HIF-1α, VEGF-A and angiogenesis via multiple signalling mechanisms.

Detection of copy number changes at the NF1 locus with improved high-resolution array CGH

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disease caused by various types of mutations in the NF1 gene. We have previously developed a locus-specific DNA microarray for detection of copy number changes at the NF1 locus by comparative genomic hybridization (CGH) analysis. The original array contains 183 probes pooled from 444 polymerase chain reaction (PCR) products. In the current work, we have used 493 probes derived from single PCR products (200--998 bp in size) to construct a higher resolution array with a smaller average probe size for molecular diagnosis of NF1. This has improved the average resolution from 12.6 kb in the previous array to 4.5 kb in the current version. The performance of the newly constructed microarray was validated with 14 well-characterized NF1 mutations for CGH analysis. These mutations represent deletions from approximately 7 kb to over 2 Mb in size. Using this array, we examined a total of 55 NF1 patients for copy number changes at the NF1 locus, detecting deletions in four of them. These results demonstrate that a locus-specific microarray constructed from single PCR products can efficiently detect copy number changes at the NF1 locus, providing a simple method for the molecular diagnosis of NF1.

Determinants and distributions of plasma total homocysteine concentrations among school children in Taiwan

BACKGROUND

Plasma total homocysteine (tHcy) level is an independent risk factor for cardiovascular disease (CVD) even among children. The purpose of this study is to evaluate the determinants and distributions of plasma tHcy levels and the relationship between plasma tHcy, folate and vitamin B12 levels among school children in Taipei.

METHODS

After multi-stage sampling, we randomly selected 1234 school children (609 boys and 625 girls) with the mean age of 13 years (from 12 to 15 years) in this study. Fasting plasma tHcy levels were measured using an ABBOTT IMx analyzer (Axis Biochemicals ASA, Oslo, Norway). Plasma folate and vitamin B12 levels were measured by ACS:180 automated chemiluminescence analyzer (Bayer, Tarrytown, NY, USA).

RESULTS

The distribution of plasma tHcy levels were skewed to the right with the mean values of 10.50 and 8.95 micromol/l and medians of 9.67 and 8.474 micromol/l for boys and girls, respectively. Plasma tHcy concentrations were lower in younger children and progressively increased with increasing age. Boys had significantly higher plasma tHcy levels than girls (10.50 +/- 4.134 vs. 8.95 +/- 2.61 micromol/l, p < 0.01) and lower plasma folate levels (6.05 +/- 2.85 vs. 6.39 +/- 2.58 nmol/l, p < 0.01), and vitamin B12 levels (444.8 +/- 158.4 vs. 495.0 +/- 181.5 pmol/l, p < 0.001). Plasma tHcy levels were significantly positively associated with anthropometric measures in boys; but these characteristics attenuated and became insignificant after adjusting for other potential confounders in girls. Plasma tHcy levels were negatively associated with plasma folate and vitamin B12 levels even after adjusting for BMI and other potential confounders in both genders.

CONCLUSIONS

From this study, the distributions of tHcy levels were skewed to the right and the boys had higher plasma tHcy levels than girls. Plasma tHcy levels were significantly positively associated with BMI among boys. Further studies are needed to evaluate the relationship between tHcy and CVD risk factors among children for the better prevention of heart disease in early life.

Relationship between plasma leptin levels and lipid profiles among school children in Taiwan--the Taipei Children Heart Study

Leptin, an adipose tissue-derived of gene product, is important in energy metabolism. However, the role of leptin in the metabolism of lipids is still not clear in humans. The purpose of this study was to evaluate the association of plasma leptin concentrations and lipid profiles among school children in Taiwan. After multistage sampling of 85 junior high schools in Taipei, we randomly selected 1264 children (617 boys and 647 girls) aged 12-16 years for this study. We measured the anthropometric variables, lifestyle factors and biochemical parameters among these children. Anthropometric measurements included body height (BH) and weight (BW) and we calculated body mass index (BMI) as the ratio of the BW to the square of the BH, expressed in kg/m2. Plasma leptin levels were measured by radioimmunoassay. We also measured lipid profiles including serum total cholesterol (CHOL), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C), apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), and lipoprotein(a) (Lp(a)) levels, and calculated low density lipoprotein-cholesterol (LDL-C) levels and CHOL to HDL-C ratio (TCHR). Girls had higher leptin, CHOL, TG, HDL-C, (LDL-C), Apo-A1, Apo-B, and Lp(a) levels and lower BMI than boys did. Plasma leptin concentrations were significantly positively correlated with TG, LDL-C, and Apo-B, but negatively with HDL-C and Apo-A1 in both the genders. Children with higher plasma leptin levels (>75th percentiles) have significantly higher TG, HDL-C, LDL-C, TCHR, and Apo-B than those with relatively lower leptin levels. In multivariate regression analyses, the association between plasma leptin level and lipid profiles (such as CHOL, TG, and Apo-B) were still significant (p < 0.05) even after adjusting for BMI among boys. However, this association became attenuated and insignificant among girls. Finally, in the model that included the standard covariates, plasma leptin was the most predictive of CHOL, TG and Apo-B levels among those school children in Taiwan. Our results suggest that plasma leptin and BMI were independently associated with the lipids and lipoprotein profiles among Taiwanese Children. In both genders, children in the top 25% of the leptin distribution have more adverse lipid and lipoprotein profiles.

Neo-centromere formation on a 2.6 Mb mini-chromosome in DT40 cells

We describe a mammalian artificial mini-chromosome lacking human alphoid DNA and mouse minor and major satellite DNA repeats. This mini-chromosome, initially recovered in a mouse embryonic stem (ES) cell line (CGR8), is 2.6 Mb in size and consists of sequences derived from the human Y chromosome and mouse chromosomes 12 and 15. It is not stable in the CGR8 cells but replicates and segregates with high fidelity after transfer into chicken DT40 cells. Combined analysis by immunocytochemistry/fluorescence in situ hybridisation (FISH) on metaphase spreads detected an active neo-centromere on the mini-chromosome in these cells. Further analysis by immunocytochemistry/FISH on stretched chromatin allowed the localisation of the CENP-C protein to the DNA sequence derived from interval 5 of the human Y chromosome.

The accuracy of segregation of human mini-chromosomes varies in different vertebrate cell lines, correlates with the extent of centromere formation and provides evidence for a trans-acting centromere maintenance activity

We show that the accuracy of mitotic segregation of three engineered, mapped human mini-chromosomes differs between human, mouse and chicken cell lines. We have studied the cause of these differences by analysing the extent of centromere formation on one mini-chromosome immunocytochemically. In human and chicken cell lines the mini-chromosomes segregate accurately and form centromeres but in one mouse cell line centromere formation is undetectable and mitotic segregation is inaccurate. These results indicate that the centromere is maintained by an activity that functions in trans and varies either in amount or specificity between different cells. Structurally defined mini-chromosomes may allow this activity to be studied.

Effects of TAK-044, a nonselective endothelin receptor antagonist, on the spontaneous and indomethacin- or methylene blue-induced constriction of the ductus arteriosus in rats

We studied the effects of TAK-044, a nonselective endothelin (ET) receptor antagonist, on the indomethacin- or methylene blue-induced constriction of the ductus arteriosus (DA) in rats and compared them with the effects on spontaneous DA constriction. Injection of TAK-044 into 21-day-old fetuses in utero was performed through the uterine wall of laparotomized mother rats under light ether anesthesia. The fetuses were autopsied 3 hr after treatment with TAK-044 (10 mg/kg) in utero and simultaneous administration to the laparotomized mother rats of indomethacin (3 mg/kg, p.o.) or methylene blue (100 mg/kg, i.p.). In the second experiment, pregnant rats were decapitated on day 21 of gestation to obtain newborn rats by cesarean delivery. Newborn rats which were given TAK-044 (2, 10 mg/kg) immediately after or 1 hr before cesarean delivery were autopsied at various times after birth. In both experiments, pups were rapidly frozen in an acetone-dry ice mixture at autopsy to evaluate the DA constriction by the whole-body freezing and shaving method. TAK-044 injection into the fetus 3 hr before autopsy completely inhibited the DA constriction induced by maternal treatment with indomethacin or methylene blue. TAK-044 caused dose-dependent inhibition of the spontaneous closure of the DA after birth. The inhibitory effect was more pronounced in pups which were given TAK-044 in utero 1 hr before birth; however, the inhibitory effect was incomplete in newborn pups. These results, together with the previous finding that BQ-123, an ETA-specific receptor antagonist, inhibits the ductal constriction induced by oxygen in vitro [Coceani et al., 1992], indicate that the ETA receptor plays a significant role in the indomethacin- or methylene blue-induced DA constriction as well as in the spontaneous DA constriction after birth, and also indicate that the inhibition of ETA receptor by TAK-044 was more easily achieved in fetuses than in neonates.

A structurally defined mini-chromosome vector for the mouse germ line

Yeast artificial mini-chromosomes have helped to define the features of chromosome architecture important for accurate segregation and replication and have been used to identify genes important for chromosome stability and as large-fragment cloning vectors. Artificial chromosomes have been developed in human cells but they do not have defined, experimentally predictable structures. Fragments of human chromosomes have also been introduced into mice and in one case passed through the germ line. In these experiments, however, the structure and sequence organization of the fragments was not defined. Structurally defined mammalian mini-chromosome vectors should allow large tracts of DNA to be introduced into the vertebrate germ line for biotechnological purposes and for investigations of features of chromosome structure that influence gene expression. Here, we have determined the structure and sequence organization of an engineered mammalian mini-chromosome, ST1, and shown that it is stably maintained in vertebrate somatic cells and that it can be transmitted through the mouse germ line.

Differential stability of a human mini-chromosome in mouse cell lines

A 4 Mb human mini-chromosome, DeltaDelta2, was transferred from Chinese hamster ovary (CHO) cells into a mouse L cell line. The mini-chromosome could be transferred intact into the L cells, with 112/119 clones maintaining a mini-chromosome of the same size as the original. Ten clones were grown for 30 days in continuous culture. The mini-chromosomes were maintained stably with or without selection at a copy number of 1-2 per cell and none experienced any size alterations, as determined by pulsed-field gel electrophoresis. Thus DeltaDelta2 is structurally and mitotically stable in L cells. This contrasts with results in embryonic stem cells, in which DeltaDelta2 is highly unstable. These findings indicate that established somatic cell lines, such as L cells and CHO cells, have less stringent controls over centromeric function than do normal embryonic cells.

Underregistration of neonatal deaths: an empirical study of the accuracy of infantile vital statistics in Taiwan

STUDY OBJECTIVE

The accuracy of the official statistic on infant deaths in Taiwan has been questioned. This study aimed to survey infant deaths nationwide, to measure associated vital statistics, and compare them with the official statistics to assess accuracy.

DESIGN AND PARTICIPANTS

A nationwide survey of all gestational outcomes occurring at > or = 20 weeks' gestation over a three day study period (15-17 May 1989) was conducted to collect data from 23 counties and cities nationwide using a two stage data collection procedure.

MAIN RESULTS

The survey derived infant death rate was 9.72 per 1000 live births, which was higher than the reported official statistic of 5.71 per 1000 live births. A more detailed examination of data on infant deaths showed that the estimated neonatal death rate of 6.68 per 1000 live births (95% confidence intervals: 3.33, 11.96 per 1000 live births) was significantly higher than the published official statistic of 1.94 per 1000 live births, while the postneonatal mortality of 3.04 per 1000 live births was comparable to the reported statistic of 3.37 per 1000 live births.

CONCLUSIONS

This study empirically documented the underregistration of infant deaths in Taiwan, particularly those occurring during the first 27 days of life.

Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini-chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re-arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini-chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.

The aging retarding effect of 'Long-Life CiLi'

'Long-Life CiLi' ('CiLi') oral liquid, is composed of superoxide dismutase (SOD), polysacchairide, vitamin C, vitamin E and trace elements which were all extracted from a natural plant fruit Cili (Rosa roxburghii Tratt) in Guizhou, China. A set of indices were evaluated after administration of 'CiLi' 10 ml Bid, for two months in 50-75 years old healthy people, the mean value of NK cell activity (22.4 +/- 10.8-->27.5 +/- 12.9%, P < 0.05), SOD (453.0 +/- 24.2-->468.6 +/- 21.3 micrograms/gHb, P < 0.001), Catalase (15.5 +/- 1.7-->17.4 +/- 3.0 U/mgHb, P < 0.001) and GSH content (2.3 +/- 0.3-->2.6 +/- 0.5 mg/gHb, P < 0.001) in erythrocytes and 'delta CO, CI, SV, SI, LVET, LVETI and AC' values increased significantly, while the serum LPO level (4.20 +/- 0.78-->3.78 +/- 0.50 nmol/ml, P < 0.001), total microcirculation weighed value (1.87 +/- 1.0-->0.92 +/- 0.5, P < 0.001), delta PVR (-241.7 +/- 733.2-->187.9 +/- 938.2, P < 0.05) and the light reaction time (Simple RT, red light: 383 +/- 128-->332 +/- 68.9 ms, P < 0.05; selective RT: red light 709 +/- 287-->566 +/- 119 ms, P < 0.05; green light 639 +/- 162-->536 +/- 80 ms, P < 0.01) decreased significantly. There were no significant differences in the control group. The mean life span of fruit flies were significantly elongated for low, medium and high concentrations 'CiLi' treatment groups than in the control group (Female: 57.6 +/- 11.3-->62.1 +/- 12.8; 69.6 +/- 14.7; 62.6 +/- 12 days; P < 0.05 approximately 0.001. Male: 56.3 +/- 9.6-->64.9 +/- 12.4; 64.5 +/- 14.5; 64.8 +/- 14.1 days, P < 0.001). It is suggested that 'CiLi' has an aging retarding and geroprotection effect.

Mammalian artificial chromosomes

The development of candidate vectors and of techniques for their manipulation by sequence targeting suggest that a mini-chromosome vector system for the mouse germline may be at hand. Mini-chromosome vectors should allow new sorts of genetic problems to be addressed experimentally and may accelerate the process of gene identification.

Molecular genetics of neurofibromatosis type 1 (NF1)

Neurofibromatosis type 1 (NF1), also called von Recklinghausen disease or peripheral neurofibromatosis, is a common autosomal dominant disorder characterised by multiple neurofibromas, café au lait spots, and Lisch nodules of the iris, with a variable clinical expression. The gene responsible for this condition, NF1, has been isolated by positional cloning. It spans over 350 kb of genomic DNA in chromosomal region 17q11.2 and encodes an mRNA of 11-13 kb containing at least 59 exons. NF1 is widely expressed in a variety of human and rat tissues. Four alternatively spliced NF1 transcripts have been identified. Three of these transcript isoforms (each with an extra exon: 9br, 23a, and 48a, respectively) show differential expression to some extent in various tissues, while the fourth isoform (2.9 kb in length) remains to be examined. The protein encoded by NF1, neurofibromin, has a domain homologous to the GTPase activating protein (GAP) family, and downregulates ras activity. The identification of somatic mutations in NF1 from tumour tissues strongly supports the speculation that NF1 is a member of the tumour suppressor gene family. Although the search for mutations in the gene has proved difficult, germline mutation analysis has shown that around 82% of all the fully characterised NF1 specific mutations so far predict severe truncation of neurofibromin. Further extensive studies are required to elucidate the gene function and the mutation spectrum. This should then facilitate the molecular diagnosis and the development of new therapy for the disease.

Two single base polymorphisms in introns 41 and 16 of the NF1 gene

We have characterized two intragenic polymorphisms in the neurofibromatosis type 1 (NF1) gene by direct sequencing of PCR products. The variants for these polymorphisms were initially detected on Hydrolink gels. One of the polymorphisms involves a G to A transition in intron 41 at the 28th base upstream of exon 42 with an observed 'G'/'A' heterozygosity of 0.42. The other polymorphism is a T to C transition in intron 16 at the 16th base upstream of exon 17 with an observed 'T'/'C' heterozygosity of 0.09. In combination with other documented polymorphisms in the NF1 gene, these variants should assist in genetic analysis of NF1 families.

Neurofibromatosis type 1 (NF1): the search for mutations by PCR-heteroduplex analysis on Hydrolink gels

Despite the extensive search for disease causing mutations in exons 28-36 of the neurofibromatosis type 1 (NF1) gene, the NF1 specific mutations so far documented account for only a small proportion of all NF1 cases. In this study, we have used 8 sets of new primers to amplify sequences throughout the NF1 gene, including 10 different exons and their flanking intron sequences. The derived PCR products from 150 independent NF1 patients and 50 normal controls were examined by heteroduplex analysis on Hydrolink gels. Three novel mutations were identified and characterised. Two of these mutations include the same 3-bp deletion (AAT) within exon 17 with a silent codon change from ACA (threonine) to ACG (threonine) and a loss of the codon ATG (methionine). The third mutation is a 10-bp deletion (TTCTCTTGGA) within exon 44 resulting in the formation of an inappropriate stop codon. These results should be useful for the further elucidation of the molecular basis of NF1.

A de novo nonsense mutation in exon 28 of the neurofibromatosis type 1 (NF1) gene

We have screened a total of 105 unrelated patients with neurofibromatosis type 1 (NF1) for mutations in exon 28 of the NF1 gene using heteroduplex analysis and single strand conformation polymorphism analysis. One novel mutation has been identified and characterised. This mutation involves a 13-bp deletion (AAACTGGCTGAGC or AACTGGCTGAGCA) from base position 5077 (or 5078) to 5089 (or 5090) of the cDNA coding sequence. This alteration leads to a reading frame shift with a premature amber termination signal (TAG) at codon 1694. In addition, there is a change from lysine to threonine at codon 1693. The truncated gene product is estimated to be 1125 amino acid residues shorter than the predicted normal protein (2818 amino acids).

[Studies on genetic engineering of human insulin-purification and characterization of human proinsulin and insulin]

E. coli DH 5 alpha cells harboring a plasmid pWR 590-BCA 4 for fused human proinsulin production were cultured. The fused human proinsulin was isolated from the fermented cells and then subjected it to cleavage with BrCN. The cleaved product was then converted to crude proinsulin-S-sulfonate using oxidative sulfitolysis. The isolation of human proinsulin-S-sulfonate was accomplished by ion exchange chromatography on QAE-sephadex A-25, followed by gel filtration on sephadex G-50. The purified human proinsulin-S-sulfonate was folded using a disulfide interchange method. The folding mixture was then chromatographed on sephadex G-50 and purified proinsulin was obtained. The proinsulin was then converted to human insulin and C-peptide by a combination cleavage with trypsin and carboxypeptidase B. The total yield of human insulin was about 5 mg/L The Zinc insulin crystals were obtained with amorphous human insulin using citrate method. The amino acid composition N-terminal sequences as well as C-terminal amino acid residues are in agreement with expected results. The hypoglycemic activity of purified human insulin is 26-27 U/mg, as judged by mouse convulsion assay, and the RIA activity is about 99% of that of porcine insulin.

DNase I-hypersensitive sites and transcription factor-binding motifs within the mouse E beta meiotic recombination hot spot

The second intron of the E beta gene in the mouse major histocompatibility complex is the site of a meiotic recombination hot spot. We detected two DNase I-hypersensitive sites in this intron in meiotic cells isolated from mouse testes. One site appears to be constitutive and is found in other tissues regardless of whether or not they express the E beta gene. Near this hypersensitive site are potential binding motifs for H2TF1/KBF1, NF kappa B, and octamer transcription factors. Gel retardation studies with mouse lymphoma cell nuclear extracts confirmed that each of these motifs is capable of binding protein. The binding of transcription factors may contribute to the enhancement of recombination potential by altering chromatin structure and increasing the accessibility of the DNA to the recombination machinery.