[Effect of corneal e-value on myopia control in children and adolescents with orthokeratology]

Objective: To investigate the influence of corneal e-value on the effectiveness of orthokeratology in controlling myopia in children and adolescents. Methods: A retrospective cohort study was conducted, involving the data from 1 563 myopic patients (1 563 eyes) who underwent orthokeratology at the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine from June 2015 to August 2021 and adhered to lens wear for at least 2 years. The cohort consisted of 737 males and 826 females with an average age of (10.84±2.13) years. Based on corneal e-value parameters obtained from corneal topography, patients were categorized into a low e-value group (n=425) and a high e-value group (n=1 138). Data on gender, age, parental myopia history, and baseline measures such as spherical equivalent (SE), axial length, and corneal e-value were collected. Differences in axial length change and corneal fluorescein staining rates were compared between the two groups at 1 and 2 years after the start of lens wear. A generalized linear mixed model was established with axial length change as the dependent variable to analyze the correlation between axial length change and baseline corneal e-value. Results: The initial age of the 1 563 myopic patients was (10.84±2.13) years, with a baseline SE of (-3.05±1.30) D. After 1 year of lens wear, the axial length change was (0.20±0.19) mm in the low e-value group and (0.24±0.20) mm in the high e-value group. After 2 years, the changes were (0.38±0.25) mm and (0.43±0.27) mm, respectively, with statistically significant differences (all P<0.05). The incidence of corneal staining after 1 year of lens wear was 9.2% (39/425) in the low e-value group and 14.1% (160/1 138) in the high e-value group. After 2 years, the rates were 15.8% (67/425) and 21.8% (248/1 138), respectively, with statistically significant differences (all P<0.05). After adjusting for parental myopia history, age, SE, and baseline axial length, the baseline corneal e-value was positively correlated with axial length change at 1 and 2 years after lens wear (all P<0.05). Conclusions: Corneal e-value is an independent factor influencing the effectiveness of orthokeratology in controlling myopia. A smaller corneal e-value is associated with slower axial length growth after orthokeratology, indicating better control of myopia in treated eyes.

[Construction of a risk prediction model for diabetes after kidney transplantation based on genome-wide association study]

Objective: To explore the clinical risk factors and susceptibility genes of diabetes after kidney transplantation (PTDM) and construct a risk prediction model for PTDM. Methods: The data of kidney transplant recipients who underwent follow-up in the Affiliated Lihuili Hospital, Ningbo University and Sir Run Run Shaw Hospital, Zhejiang University School of Medicine from January 2001 to December 2022 were retrospectively analyzed. The recipients were divided into PTDM group and Non-PTDM group according to whether they were complicated with PTDM. The differences in clinical indicators between the two groups were compared, the risk factors affecting the incidence of PTDM were determined, and susceptibility genes of PTDM were screened by genome-wide association study (GWAS). PTDM risk prediction models based only on clinical indicators (Model 1) and clinical indicators combined with susceptibility genes (Model 2) were established respectively, and the predictive performance of the two prediction models was compared. Finally, the Nomogram of the optimal model was drawn, and the discrimination, calibration and clinical applicability of the model were evaluated. Results: A total of 113 kidney transplant recipients (70 males and 43 females) were included, with an average age of (46.2±10.8) years. There were 51 cases in PTDM group and 62 cases in Non-PTDM group. The related factors screened by GWAS and logistic regression analysis included family history of diabetes (OR=88.912, 95%CI: 5.827-1 356.601, P=0.001), preoperative triglyceride (TG) (OR=1.888, 95 %CI: 1.150-3.098, P=0.012), uric acid (UA) (OR=1.011, 95%CI: 1.000-1.022, P=0.045) and rs802707 (OR=10.046, 95%CI: 1.462-69.042, P=0.019). The area under the curve (AUC) of the receiver operating characteristics analysis (ROC) predicted by Model 1 for PTDM was 0.891 (95%CI: 0.811-0.972), with the sensitivity of 0.889 and the specificity of 0.742. The AUC of ROC curve predicted by Model 2 for PTDM was 0.930 (95%CI: 0.864-0.995), with the sensitivity of 0.885 and the specificity of 0.900. Conclusions: Family history of diabetes, preoperative TG and UA, and rs802707 are significantly associated with the occurrence of PTDM. In addition, the combination of susceptibility genes could improve the predictive ability of clinical indicators for the risk of PTDM.

[Comparison of the effects and safety of dydrogesterone and medroxyprogesterone acetate on endometrial hyperplasia without atypia: a randomized controlled non-inferior phase Ⅲ clinical study]

Objective: To compare the effects and safety of dydrogesterone (DG) and medroxyprogesterone acetate (MPA) on the treatment in patients with endometrial hyperplasia without atypia (EH). Methods: This was a single-center, open-label, prospective non-inferior randomized controlled phase Ⅲ trial. From February 2019 to November 2021, patients with EH admitted to the Obstetrics and Gynecology Hospital of Fudan University were recruited. Enrolled patients were stratified according to the pathological types of simple hyperplasia (SH) or complex hyperplasia (CH), and were randomised to receive MPA or DG. Untill May 14, 2022, the median follow-up time after complete response (CR) was 9.3 months (1.1-17.2 months). The primary endpoint was the 6-month CR rate (6m-CR rate). The secondary endpoints included the 3-month CR rate (3m-CR rate), adverse events rate, recurrence rate, and pregnancy rate in one year after CR. Results: (1) A total of 292 patients with EH were enrolled in the study with the median age of 39 years (31-45 years). A total of 135 SH patients were randomly assigned to MPA group (n=67) and DG group (n=68), and 157 CH patients were randomly assigned to MPA group (n=79) and DG group (n=78). (2) Among 292 patients, 205 patients enrolled into the primary endpoint analysis, including 92 SH patients and 113 CH patients, with 100 patients in MPA group and 105 in DG group, respectively. The 6m-CR rate of MPA group and DG group were 90.0% (90/100) and 88.6% (93/105) respectively, and there were no statistical significance (χ²=0.11, P=0.741), with the rate difference (RD) was -1.4% (95%CI:-9.9%-7.0%). Stratified by the pathology types, the 6m-CR rate of SH patients was 93.5% (86/92), and MPA group and DG group were respectively 91.1% (41/45) and 95.7% (45/47); and the 6m-CR rate of CH patients was 85.8% (97/113), and MPA group and DG group were 89.1% (49/55) and 82.8% (48/58) respectively. The 6m-CR rates of the two treatments had no statistical significance either (all P>0.05). A total of 194 EH patients enrolled into the secondary endpoint analysis, including 88 SH patients and 106 CH patients, and 96 patients in MPA group and 98 in DG group, respectively. The 3m-CR rate of SH patients were 87.5% (77/88), while the 3m-CR rates of MPA group and DG group were 90.7% (39/43) and 84.4% (38/45), respectively; the 3m-CR rate of CH patients was 66.0% (70/106), and MPA group and DG group had the same 3m-CR rate of 66.0% (35/53). No statistical significance was found between the two treatments both in SH and CH patients (all P>0.05). (3) The incidence of adverse events between MPA group and DG group had no statistical significance (P>0.05). (4) A total of 93 SH patients achieved CR, and the cumulative recurrence rate in one year after CR were 5.9% and 0 in MPA group and DG group, respectively. While 112 CH patients achieved CR, and the cumulative recurrence rate in one year after CR were 8.8% and 6.5% in MPA group and DG group, respectively. There were no statistical significance between two treatment groups (all P>0.05). Among the 93 SH patients, 10 patients had family planning but no pregnancy happened during the follow-up period. Among the 112 CH patients, 21 were actively preparing for pregnancy, and the pregnancy rate and live-birth rate in one year after CR in MPA group were 7/9 and 2/7, while in DG group were respectively 4/12 and 2/4, and there were no statistical significance in pregnancy rate and live-birth rate between the two treatment groups (all P>0.05). Conclusions: Compared with MPA, DG is of good efficacy and safety in treating EH. DG is a favorable alternative treatment for EH patients.

Efficacy of dual enkephalinase inhibition in a preclinical migraine model is mediated by activation of peripheral delta opioid receptors

OBJECTIVE

The aim of this study was to evaluate whether elevating levels of enkephalin by inhibiting their degradation can attenuate stress-induced migraine-like behaviors in mice.

BACKGROUND

Previous studies in animals have suggested the delta opioid receptor (DOR) as a novel migraine target. The primary endogenous ligands for DOR are enkephalins and their levels can be increased by pharmacological inhibition of enkephalinases; however, it is not clear whether enkephalinase inhibition can be efficacious in preclinical migraine models through activation of DOR or whether other opioid receptors might be involved. Further, it is not clear whether opioid receptors in the central nervous system are necessary for these effects.

METHODS

This study used a model of repetitive restraint stress in mice that induces periorbital hypersensitivity and priming to the nitric oxide donor sodium nitroprusside (SNP; 0.1 mg/kg). Von Frey filaments were used to measure periorbital mechanical thresholds and grimace scores were evaluated by observing mouse facial features. Animals were treated with the dual enkephalinase inhibitor (DENKI) PL37.

RESULTS

On day two post-stress, PL37 given to mice via either intravenous injection (10 mg/kg) or oral gavage (20 mg/kg) significantly attenuated stress-induced periorbital hypersensitivity and facial grimace responses. Additionally, both intravenous (10 mg/kg) and oral gavage (20 mg/kg) of PL37 prior to SNP (0.1 mg/kg) administration on day 14 post-stress significantly reduced SNP-induced facial hypersensitivity. Injection of the DOR antagonist naltrindole (0.1 mg/kg) but not the mu-opioid receptor antagonist CTAP (1 mg/kg) prior to PL37 treatment blocked the effects. Finally, pretreatment of mice with the peripherally restricted opioid receptor antagonist naloxone methiodide (5 mg/kg) blocked the effects of PL37.

CONCLUSIONS

These data demonstrate that inhibiting enkephalinases, and thus protecting enkephalins from degradation, attenuates stress-induced migraine-like behavior via activation of peripheral DOR. Peripheral targeting of endogenous opioid signaling may be an effective therapeutic strategy for migraine.

[Research Progress on the Role of Mitochondrial DNA in the Pathogenesis of Chronic Liver Disease]

Mitochondrial DNA is the mitochondria's own genetic material located within the mitochondrial matrix and is involved in cellular metabolism and energy supply. Mitochondrial DNA damage exacerbates oxidative stress by increasing the release of reactive oxygen species, while mitochondrial DNA release also triggers apoptosis and activates immune inflammatory responses through damage-related molecular patterns. Mitochondrial autophagy regulates mitochondrial DNA damage and release through a negative feedback mechanism to maintain intracellular homeostasis. Recent studies have shown that the occurrence and development of chronic liver disease are closely related to mitochondrial DNA-mediated immune inflammatory responses and oxidative stress.

[A survey on sexual needs and factors of HIV risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture]

Objective: To understand sexual needs and factors of risky sexual behaviors among elderly men at different ages in two communities of Qiandongnan Miao and Dong autonomous prefecture and provide basis for targeted HIV prevention and intervention. Methods: Two communities in the prefecture were selected as study sites. Questionnaire surveys were carried out among elderly men aged 50 and over who visited or consulted in the communities from June to December 2018, and they were tested for HIV and syphilis antibodies. Results: Among 400 elderly men, 209 (52.2%) were 50-64 years old, and 191(47.8%) were above 65 years old. They were mainly Miao people, accounting for 66.3% (265/400), and 235 (58.8%) had an education no more than 6 years. HIV awareness of the two age groups were only 25.8% (54/199) and 26.2% (50/191), respectively. Among those aged 50-64, 142 (68.0%) felt normal sexual desire, and 153 (73.6%) reported penile erections or erections in most cases whenever sex, and 52.9% (110) ejaculated most of the time. HIV prevalence was 1.0% (4/400). Compared with the over 65-year-old group, the proportion of having sex with spouse/stable partners (89.5%, 179/200), proportion of no condom use with their spouse/stable sexual partners during the most recent sex (93.8%, 168/179), proportion of having casual sex (11.0%, 23/209) and commercial sex (3.8%, 8/209) were all higher among 50-64 age group. In comparison to those aged over 65 years old, average monthly income>3 000, and use of sex helper, aged 50-64 (OR=2.70, 95%CI: 1.22-5.95), average monthly income ≤1 000 yuan (OR=2.79, 95%CI: 1.25-6.21), and no use of sex helper (OR=3.78) (95%CI: 1.65-8.67) were related factors of HIV risky sexual behavior last time. Conclusion: Elderly men in the minority prefecture had low HIV awareness. Compared with those≥65 years old, the 50-64 age group had more active sexual behaviors and higher sexual needs. Those from 50-64 age group, with lower economic level and good sexual ability were more likely to have HIV risky sexual behaviors.

[Brief discussion on the taboo and application of stem cell transplantation in the treatment of liver cancer]

Liver cancer is the second-highest mortality cancer in China. It is highly occult, and there is no effective treatment so far. In recent years, stem cell transplantation, especially mesenchymal stem cell (MSCs) transplantation, has been widely used in the treatment of various diseases. Nevertheless, the industry has reached a consensus that malignant tumors are the forbidden area of this transplantation therapy. This is closely related to the two main characteristics of stem cells themselves, namely "self-renewal" and "pluripotency". The following is an overview of the reasons why stem cells, especially MSCs, have become taboo in tumor treatment and their potential application methods, so as to provide some references for further research on this therapy.

PAX3 silencing suppresses gastric cancer proliferation and angiogenesis via MET/PI3K signaling

PAX3 is the key factor in cell signal transduction pathway and may be involved in the regulation of cancer cell proliferation, differentiation and migration. The aim of the study was to investigate the effects and mechanism of PAX3 silencing on the gastric cancer. Specific PAX3 silencing was performed both in vitro and in vivo using small-interfering RNAs (siRNAs). The proliferation, apoptosis and angiogenesis of gastric cancer cells were assessed using MTT assay, flow cytometry and in vitro tube formation assay. Mice with gastric xenografts, which expressed either si-PAX3 or non-coding siRNA (si-NC), were developed and the effects of PAX3 silencing on tumor progression were evaluated. PCNA is a proliferating cell nuclear antigen and can be used as an index for evaluating cell proliferation status. Immunocytochemistry assay was used to quantify PAX3 and PCNA expression. After 4 weeks of tumor inoculation, tumor tissues were weighed. Tumor tissue morphology and apoptosis were evaluated using HE staining and TUNEL assay. In order to investigate the effect of silencing PAX3 on cell apoptosis, angiogenesis and MET/PI3K pathway, quantitative real-time PCR (qRT-PCR) or western blot were used to detect the expression levels of caspase-3, VEGF, MET, p-MET, PI3K and p-PI3K. After PAX3 silencing, PAX3 expression was significantly decreased in two gastric cancer cell lines, MKN-28 and SGC-7901 (p<0.05 vs Control). PAX3 silencing reduced cell proliferation, induced cell apoptosis and inhibited tube formation. PAX3 and PCNA expression were also significantly decreased. In mice, silencing PAX3 significantly inhibited tumor growth and decreased microvessel density in tumor. PAX3 silencing also decreased cell density in tumors, which concurred with increased apoptosis and PAX3 expression. PAX3 silencing upregulated the expression of caspase-3, downregulated the expression of VEGF, phosphorylation of PI3K and MET. Our data showed that these anti-tumor effects of PAX3 silencing might be attributed to its role in inducing cell apoptosis and inhibiting angiogenesis.

[Influence of gender, age and season on thyroid hormone reference interval]

Objective: Using clinical "big data" , to investigate the factors that affect the levels of thyroid hormones, and to explore the partitioning criteria for reference intervals (RI) of these hormones. Methods: An observation study was conducted. Information of 107 107 individuals undergoing routine physical examination in Peking Union Medical College Hospital from September 1(st,) 2013 to August 31(st,) 2016 was collected, thyroid hormone of these subjects were detected. To explore the test results distribution and differences of TSH, FT4 and FT3 by gender and age; according to the seasonal division standard of China Meteorological Administration, the study period was divided into four seasons, and the seasonal fluctuation on TSH was analyzed.To define the appropriate partition by gender, age and season according to significant difference analysis. Results: In male and female, the distributions of TSH were 1.779(0.578-4.758), 2.023(0.420-5.343)mU/L, respectively, and the level of TSH in female was higher than in male (Z=-37.600, P<0.001). The distributions of FT4 were 0.127(0.098-0.162), 0.117(0.091-0.151) μg/L, the distributions of FT3 were 3.33(2.47-3.74), 3.01(2.35-3.57)ng/L. And the level of FT4, FT3 in female were significantly lower than in male (Z=-94.000, -154.600, all P<0.001). Furthermore, males were divided into two groups by 65 years old and female were divided by 50 years old, respectively, and the distributions of TSH in male and female of older group were 1.818(0.528-5.240), 2.111(0.348-5.735)mU/L, in younger group were 1.778(0.582-4.696), 1.991(0.427-5.316)mU/L. The level of TSH in older group was significantly higher than in younger group (Z=-2.269, -10.400, all P<0.05), and the distribution of TSH in older group was much wider than in younger. The distribution of whole in spring, summer and autumn was 1.869( 0.510-5.042)mU/L, in winter was 1.978(0.527-5.250) mU/L, and the difference between them had statistical significance (Z=-15.000, P<0.001). Conclusions: Gender and age significantly affect the serum levels of TSH, FT4, and FT3, the distribution of TSH in female and elder group are wider than in male, and that of FT4, FT3 are lower.Seasons significantly affect the serum TSH level, the peak value is observed in winter. There are obviously differences between "rough" RIs and manufacture recommended RIs. Each laboratory should establish reference intervals for thyroid hormones on the premise of appropriate grouping.

[Analysis of Spatial Clustering of HIV infected in men who have sex with men in Chongqing of 2004-2015]

Objective: To analyze the spatial clustering characteristics of HIV/AIDS among men who have sex with men (MSM) in Chongqing from January 2004 to December 2015 and understand the HIV/AIDS related behaviors among MSM by interview. Methods: Data related to MSM who were infected with HIV and whose present address were in Chongqing, were collected from Information System on the HIV/AIDS Prevention and Control. Information included the age when the information was inputted, address, occupation, education level, and marital status. The total number of MSM who were infected with HIV and reported was 6 604 in Chongqing. Those with unknown address were ruled out. The spatial autocorrelation analysis and the local spatial autocorrelation analysis were carried out by using ArcGIS 10.3. In addition, in November 2015 and May 2016, using a convenience sampling, we conducted one-on-one interviews among 23 MSM in the Chongqing Center for Disease Control and prevention.

INCLUSION CRITERIA

Receiving voluntary counseling and testing in the urban area of Chongqing and willing to participate in the interview by oral informed consent; male and self-described as MSM. The content of the interview included basic information, sexual orientation, sexual role, the main place of making friends, the main place of sexual behavior, a long-term experience in other provinces and drug abuse. Results: The HIV/AIDS reported number in Chongqing from 2004 to 2015 showed an uptrend, except in 2010. The age distribution of 6 604 cases of HIV positive patients was mainly concentrated in the 15-34 years old, about 68.5% (4 522 cases). There was a positive spatial autocorrelation in MSM, except 2005 (Moran's I=-0.046, P=0.823), form 2004 to 2015, Global Moran's I values were 0.308, 0.254, 0.335, 0.683, 0.673, 0.558, 0.620, 0.673, 0.685, 0.654 and 0.649, respectively; all P values were <0.01. The result of local spatial autocorrelation analysis showed that high-high accumulation area development in Chongqing city was divided into two stages in 2004-2015, which were Yuzhong, Jiangbei, and Shapingba district in 2004-2007 and the expanded Jiulongpo, Nan'an, and Yubei district in 2008-2015. Qualitative interviews results revealed that the age of the respondents was 20-44, and the mainly way of making friends were using mobile phone App and internet (17 participants). Most of the participants (11 participants) were making friends in the bar. The majority of respondents would ask the friends or themselves to use condoms when meeting with them the first time (19 participants), and 8 of respondents reported that they would not use condoms when their old friends refused to use condoms. Conclusion: The HIV infected MSM mainly aged between 15-34 years old and the spatial distribution of HIV/AIDS among MSM was clustered in economically developed main area in Chongqing. MSM began to make friends on the Internet, and could not adhere to using condom, which indicated that we should focus on internet intervention to find more efficacious interventions.

[Study on the role of NALP3 inflammasome in Porphyromonas gingivalis lipopolysaccharide induced RAW264.7]

Objective: To illuminate the effect of NALP3 inflammasome on regulating the expression of cytokines of macrophages in periodontitis. Methods: RAW264.7 cells were cultured and divided into three groups. The first group stayed normal as control, the second group was stimulated by 1 mg/L Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS), the third group was pretreated with AC-YVAD-CMK (caspase-1 inhibitor) before stimulated with 1 mg/L Pg LPS. RAW264.7 cells pretreated with various concentrations (0, 5, 10, 25, 50, 75, 100, 200 μmol/L) of AC-YVAD-CMK for 2 h, and stimulated by 1 mg/L Pg LPS for 24 h in the third group. After that, cell survival rate were detected by cell counting kit-8. Every group cells gene transcription of NALP3 and interleukin-1β (IL-1β) were detected by quantitative real-time PCR (qPCR) after 6 h, protein expression of NALP3 and IL-1β were separately detected by Western blotting and enzyme linked immunosorbent assay (ELISA) after 24 h, respectively. Results: It is observed that treatment with 5, 10, 25, 50, 75, 100, 200 μmol/L AC-YVAD-CMK did not significantly affect the viability of RAW264.7 cells. qPCR showed that mRNA expression of IL-1β level (1.03±0.08, 5.48±0.22, 4.31±0.20) and NALP3 level (0.96±0.05, 2.62±0.44, 1.73±0.09). Western blotting showed that protein expression of NALP3 level (1.00±0.10, 2.34±0.04, 1.64±0.04), ELISA showed protein secretion of IL-1β level ([40.20±0.25], [61.50±1.81], [52.40±1.91] ng/L). After stimulated by Pg LPS, mRNA and protein expression of IL-1β (P<0.01, P<0.01) and NALP3 (P<0.01, P<0.01) significantly increased; but the expression of IL-1β (P=0.002, P=0.027) and NALP3 (P<0.01, P<0.01) were decreased when pretreated with AC-YVAD-CMK. Conclusions: NALP3 inflammasome signal pathway can be activated by Pg LPS in RAW264.7. Block of the pathway can inhibit Pg LPS-induced secretion of cytokines.

[The clinical characteristics of 128 childhood- and adolescent-onset hypoparathyroidism in Peking Union Medical College Hospital: a retrospective analysis]

Objective: To study the clinical characteristics of childhood- and adolescent- onset hypoparathyroidism. Methods: The clinical data of 128 hypoparathyroidism patients with onset before the age of 18 years were collected and analyzed retrospectively. Results: The predominant features of the hypoparathyroidism were carpopedal spasm (89.3%, 108/121) and seizures (66.1%, 84/127). Intracranial calcification was identified in 89.4%(101/113) of the patients. Duration is an independent predictive factor (OR=1.483, P=0.011) for intracranial calcification. All the patients were treated with calcium and vitamin D or its metabolites. Hypercalciuria was associated with serum calcium (P=0.016). Conclusions: Carpopedal spasm and seizures were the main manifestations of childhood- and adolescent- onset hypoparathyroidism. Calcium and vitamin D or its metabolites are effective. Monitoring the concentration of serum and urinary calcium is of highly importance for the prevention of hypercalciuria.

Enhanced anaerobic digestion of waste activated sludge of low organic content in a novel digester

A novel digester, termed an internal circulation anaerobic digester (ICAD), was developed to intensify sludge digestion. It consists of reaction zone, settling zone, thickening zone, riser and downcomer. Internal circulation in the digester is intensified by backflow biogas. The mesophilic ICAD treating thermal pretreated waste activated sludge with volatile suspended solids (VSS)/suspended solids (SS) of 0.45-0.49 was conducted in this study to reduce and stabilize the low organic content sludge. The results showed that the VSS removal rate and biogas rate reached 46.0% and 0.72 m(3)/kg VSS(fed) at hydraulic retention time (HRT) of 15 days. VSS/SS and soluble chemical oxygen demand (SCOD) of the effluent sludge ranged from 0.39 to 0.41 and 274 mg/L to 473 mg/L, respectively, under various HRTs from 10 to 27 days. The degradation ability of ICAD derived from the improved mass transfer by internal circulation and long solid retention time at short HRT is compared with continuous stirred tank reactor.

Fam83h is associated with intracellular vesicles and ADHCAI

Defects in FAM83H on human chromosome 8q24.3 cause autosomal-dominant hypocalcified amelogenesis imperfecta (ADHCAI). FAM83H does not encode a recognizable signal peptide, so we predicted that the Fam83h protein functions within the cell. We tested this hypothesis by constitutively expressing mouse Fam83h with green fluorescent protein (GFP) fused to its C-terminus in HEK293 and HeLa cell lines. Green fluorescent signal from the Fam83h-GFP fusion protein was associated with perinuclear vesicles, usually in the vicinity of the Golgi apparatus. No signal was observed within the nucleus. In addition, we identified FAM83H nonsense mutations in Hispanic (C1330C>T; p.Q444X) and Caucasian (c.1192C>T; p.Q398X) families with ADHCAI. We conclude that Fam83h localizes in the intracellular environment, is associated with vesicles, and plays an important role in dental enamel formation. FAM83H is the first gene involved in the etiology of amelogenesis imperfecta (AI) that does not encode a secreted protein.

Partial nitrification to nitrite for treating ammonium-rich organic wastewater by immobilized biomass system

This study focused on the characteristics of the partial nitrification and degradation of organics with immobilized biomass beads in the treatment of ammonium-rich organic wastewater. Sodium alginate (SA) was selected as the best entrapment support after comparing partial nitrification rate and adsorption efficiency. The immobilization methods were optimized by an orthogonal experiment. Zeta position and BET surface area were used to explain the adsorption behavior of SA immobilized beads. FT-IR revealed that a SA immobilized biomass bead was not a simply physical mixture of SA and biomass. The porous structure of SA immobilized biomass beads were observed by scanning electron microscopy (SEM), which confirmed the porosity of the beads. According to the experimental data, the effects of pH and temperature on partial nitrification and COD removal were evidently weakened in SA immobilized biomass beads due to the "protective" effect of immobilization, whereas the effects of HRT and DO were enhanced.

Comparison of partial nitrification to nitrite for ammonium-rich organic wastewater in sequencing batch reactors and continuous stirred-tank reactor at laboratory-scale

The combined partial nitrification/Anammox process is especially suitable for the treatment of influents with low C/N ratio. However, many nitrogenous wastewater are also rich in organics. Two systems (continuous stirred-tank reactor (CSTR) and sequencing batch reactor (SBR)) are commonly used to achieve nitrite accumulation, but no complete comparison between these two systems for treating different wastewater has been reported. The objective of this paper was to compare the partial nitrification in CSTR and SBR for the treatment of ammonium-rich organic wastewater. The result showed that it took a shorter time to startup partial nitrification in CSTR, but SBR was a better option for treating ammonium-rich organic wastewater with C/N lower than 0.34. With increase HRT to 48 h, excellent nitrite accumulation could be achieved in both reactors for wastewater containing landfill leachate. For subsequent anammox, CSTR was more suitable when leachate percentage ranged from 35% to 40%.

Genetic engineering of Periplaneta fuliginosa densovirus as an improved biopesticide

The smoky-brown cockroach (Periplaneta fuliginosa) densovirus (PfDNV) has previously shown potential in urban pest control. To improve its efficacy as a biopesticide, the genome of PfDNV was engineered by inserting the insect-specific toxin gene BmKIT1 in the open reading frame encoding the major structural proteins. A green fluorescent protein (GFP) marker was tagged to the BmKIT1 at its C-terminus for in vivo imaging using Confocal laser scanning microscopy (CFSM). Using a virion rescue strategy, the genomes of recombinant and wild-type (wt) PfDNV were then cotransfected in P. fuliginosa nymphs. Reverse transcription PCR (RT-PCR) showed that the inserted BmkIT1 genes were expressed in the P. fuliginosa nymphs 48 h after cotransfection. CFSM and transmission electron microscopy also confirmed the generation of virus particles and expression of BmKIT1-GFP fusion protein in the cotransfected nymphs. The recombinant viruses remained infective to P. fuliginosa nymphs in feeding tests. Using the LT(50) bioassay method, the coninfection of the recombinant and wt PfDNV killed the P. fuliginosa nymphs approximate 32% faster than wt PfDNV only. This is the first report showing the improvement of engineered densovirus for the potential application of biopesticide.

Amelogenin p.M1T and p.W4S mutations underlying hypoplastic X-linked amelogenesis imperfecta

Mutations in the human amelogenin gene (AMELX, Xp22.3) cause a phenotypically diverse set of inherited enamel malformations. We hypothesize that the effects of specific mutations on amelogenin protein structure and expression will correlate with the enamel phenotype, clarify amelogenin structure/function relationships, and improve the clinical diagnosis of X-linked amelogenesis imperfecta (AI). We have identified two kindreds with X-linked AI and characterized the AMELX mutations underlying their AI phenotypes. The two missense mutations are both in exon 2 and affect the translation initiation codon and/or the secretion of amelogenin (p.M1T and p.W4S), resulting in hypoplastic enamel. Primary anterior teeth from affected females with the p.M1T mutation were characterized by light and scanning electron microscopy. The thin enamel had defective prism organization, and the surface was rough and pitted. Dentin was normal. The severity of the enamel phenotype correlated with the predicted effects of the mutations on amelogenin expression and secretion.

Antimicrobial susceptibility of Haemophilus influenzae among children in Beijing, China, 1999-2000

A study on the nasopharyngeal carriage and antimicrobial susceptibility of Haemophilus influenza among children was conducted in Beijing Children's Hospital from April to May 2000. The study included 292 children between 1 and 60 mo of age with acute upper respiratory tract infection. Nasopharyngeal swabs from these patients were cultured, and 105 Haemophilus influenzae strains were isolated, 3 of which were type b. Antibiotic susceptibility of the strains was determined using disk diffusion and E-tests and the results compared with those of isolates from children with pneumonia in 1999. The carriage rate of Haemophilus influenzae was 36.0% (105/292). It was found that 4.8% and 1.0% of isolates were resistant to ampicillin and cefaclor, respectively, and 5.7%, 16.2% and 77.1% were resistant to chloramphenicol, tetracycline, and sulphamethoxazole/trimethoprim, respectively. Amoxicillin/clavulanic acid, cefuroxime, ceftriaxone, azithromycin, and clarithromycin were uniformly active to all strains. Compared with the data from 1999, there was a significant increase in resistance to tetracycline (from 12.7% in 1999 to 16.2%) and sulphamethoxazole/trimethoprim (from 40.5% in 1999 to 77.1%).

CONCLUSION

H. influenzae isolates from outpatients in Beijing Children's Hospital had low ampicillin resistance and were sensitive to amoxicillin/clavulanic acid. Sulphamethoxazole/ trimethoprim resistance rates increased rapidly compared with those in the 1999 data. Further surveillance investigations are important for the choice of empiric therapy of acute respiratory tract infection.

Chromosomal analysis of group B streptococcal clinical strains; bac gene-positive strains are genetically homogenous

A collection of 45 epidemiologically unrelated Streptococcus agalactiae strains (group B Streptococcus, GBS), belonging to different serotypes, isolated from pregnant women in China and Russia was studied. Strains were characterized by pulsed-field gel electrophoresis (PFGE) employing hybridization with nine genes potentially involved in virulence. Molecular sizes of GBS genomes varied from 2030 to 2290 kb. Location of the genes under study bac, bca, glnA, scpB, cyl, hylB, lmb, scaA and cfb on the GBS genomes was found to be conserved irrelevant to the serotype. Potential virulence genes scpB, hylB, lmb were located on a 91-kb SmaI fragment that is equal to 4.5% of total genome. Ribotyping of the strains under study revealed three different HindIII, nine EcoRI and 12 PvuII ribotypes among 45 strains. A strong correlation between the PvuII ribotype and the presence of the bac gene was observed, with 21 of 22 bac-positive strains belonging to the same PvuII ribotype P1. PFGE patterns of bac-positive strains were also similar. The possibility of close genetic relatedness of all bac-positive strains is discussed.

[Study of normal range of speed of sound in tibia in Beijing area]

OBJECTIVE

To study the normal reference value of adult tibial speed of sound (tibia SOS) in Beijing region.

METHODS

951 normal volunteers (male/female = 461/490) were included in this study. Speed of sound were measured in the middle of tibia by ultrasound scan (Sound Scan 2000, Myrid, Isereal). According to their gender and age, all subjects were divided into different subgroup by 10 year-age period.

RESULTS

The peak value of SOS presented in 30-39 years period in both male and female. The peak value was higher in males than in females. After reach the peak value, the tibial SOS begin to decline. The decreasing rate was fast in SOS were found at 50-59 period in female and over 50-59 years old in male. The tibia values of SOS of postmenopausal was obviously lower than that of premenopausal women. The relationship of menopausal duration and the values if tibial SOS was found to be a non-linear curve, which included 3 stages: the quick decrease, stabilization and further decrease.

CONCLUSION

The tibia values of SOS provides a kind of meaningful diagnostic criteria of osteoporosis.

Species distribution of polymeric aluminium-ferrum--timed complexation colorimetric analysis method of Al-Fe-ferron

The effects of the colorimetric buffer solutions were investigated while the two colorimetric reactions of Al-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexation colorimetric analysis method of Al-Fe-ferron in view of the total concentration of (Al + Fe) was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 nm and the testing pH value was 5. With a comparison of the ratios of nAl/nFe, the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were various in both the molar nAl/nFe ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total [Al + Fe] which ranged from 10(-5) to 10(-4) mol/L.

The treatment of osteomyelitis with gentamicin-reconstituted bone xenograft-composite

We have developed a new drug-delivery system using reconstituted bone xenograft to treat chronic osteomyelitis. This material, which has the capabilities of osteoinduction and osteoconduction, was supplemented with up to 2000 times the minimum inhibitory concentration of gentamicin against Staphylococcus aureus to prepare a gentamicin-reconstituted bone xenograft-composite (G-RBX-C). In a rabbit model, we evaluated the release of gentamicin from this composite in vivo, its capability for induction of ectopic bone and the repair of segmental defects of the radius. There was a high level of concentration of antibiotics, which was sustained for at least ten days. In the study of induction of ectopic bone, there was abundant woven bone in the G-RBX-C group two weeks after operation. At 16 weeks after implantation of G-RBX-C the radial defects had been repaired, with the formation of lamellar bone and recanalisation of the marrow cavity. Our findings suggest that G-RBX-C may be useful in the treatment of chronic osteomyelitis.

[Construction of human bone morphogenetic protein-2 expressing eukaryotic vector]

OBJECTIVE

To construct human bone morphogenetic protein-2(hBMP-2) expressing eukaryotic vector and observe whether it can be expressed in eukaryotic cells.

METHODS

pUC19 was digested with Sal I and Xba I. The resulting Sal I-Xba I fragment (1.24 kb) which contains the full length of human BMP-2 cDNA was separated on agarose gel and ligated into eukaryotic expression vector pcDNA3 digested with XhoI and XbaI. The recombinant pcDNA3-hBMP-2 plasmid was transferred into fibroblasts cell line NIH3T3. The stable expression of hBMP-2 in the positive cells G418 selected was determined by in situ hybridization and immunohistochemical analysis.

RESULTS

The two fragments digested from recombinant pcDNA3-hBMP-2 plasmid by EcoR I and Xba I represented 1.3 kb and 5.38 kb respectively by agarose electrophoresis, meanwhile the Xho I site was disappeared in pcDNA3-hBMP-2 indicating the successful construction of recombinant pcDNA3-hBMP-2 plasmid. Stable expression of hBMP-2 in pcDNA3-hBMP-2 transfected cells was confirmed by in situ hybridization and immunohistochemical analysis.

CONCLUSION

hBMP-2 expressing eukaryotic vector is successfully constructed and can be expressed in eukaryonic cells.

[Osteoarticular allografts for repairing large bone or osteoarticular defects]

OBJECTIVE

To evaluate clinical outcome of bone or osteoarticular allografts.

METHODS

From September 1991 to November 1997, large bone or osteoarticular defects secondary to bone tumors resection in 36 patients and severe trauma in 2 patients were repaired by deep frozen or lyophilized allogeneic osteoarticular or diaphysis graft.

RESULTS

No obvious immune rejection to the grafts was observed in most of the patients in early stage after operation. The patients were followed up from 1 year and five months to 7 years and five months with an average of 4.2 years. Limb function was satisfactory in 74.19% of the 31 survival patients with large osteoarticular or diaphysis allografts.

CONCLUSION

Cryopreserved or lyophilized allogeneic osteoarticular grafts with decreased antigenicity and good biocompatibility are suitable materials for repairing large bone or osteoarticular defects.

Effects of salvianolic acid-A on rat hepatic stellate cell proliferation and collagen production in culture

AIM

To investigate the effects of salvionolic acid-A (SA-A), one of main effective components of Salvia miltiorrhiza for its antifibrotic action, on the cell proliferation and collagen production in cultured hepatic stellate cells (HSC).

METHODS

HSC were isolated through in situ perfusion of liver with pronase E and collagenase, and gradient centrifugation with Nycodenz. The cultured HSC were incubated with SA-A 0.1-100 mumol/L for 24 h. MTT spectrometric assay and intercellular incorporation of methyl-[3H]thymidine ([3H]TdR) was used to assess the cell proliferation. The amount of collagen was semi-quantified by ponceau staining and image analysis, the amount of type I collagen secretion was measured with ELISA and normalized by the total protein of cell layer. The total RNA was prepared from the control cells and the drug treated cells respectively, and the expression of pro-collagen alpha 2 (I) mRNA was semi-quantitatively analyzed with RT-PCR.

RESULTS

SA-A 100 mumol/L showed a little cytotoxity, SA-A 0.1-10 mumol/L did not influence cell morphology, and SA-A 1-100 mumol/L decreased the cell proliferation significantly in a concentration-dependent manner (P < 0.05). SA-A 1, 10, 100 mumol/L decreased the cell collagen deposition by 78.6%, 71.8%, and 61.3% of the control respectively (P < 0.05), and decreased type I collagen secretion to 53.1%, 52.6%, and 49.5% (P < 0.01 or P < 0.05). Both SA-A 1 and 10 mumol/L downregulated procollagen alpha 2 (I) mRNA expression remarkably (P < 0.05).

CONCLUSION

SA-A inhibited HSC proliferation and collagen expression. The inhibitory effect on HSC activation is the main mechanism of SA-A action against liver fibrosis.

[Material selection and structural design of simulated space module for field]

OBJECTIVE

To select the suitable material for the structure of simulated space cabin to meet the special requirements which the unitary metallic material cannot do.

METHOD

The structural material was selected through comparison between the mechanical properties of fiber reinforced plastics (FRP) and a few conventional metallic materials. The content and arrangement of the fibers in the composite material were suitably designed according to load condition and structural shape of the cabin.

RESULT

High strength and high stiffness, light weight, anti-fatigue and shock proof were achieved for the whole module structure. It meets the medical and hygienic standard for hazardous gases.

CONCLUSION

The structural design of fiber glass reinforced plastics composite module was proved to be successful. It reduced the weight of the module body, and increased the strength and toughness of the whole module.

[Actions of salvianolic acid A on CCl4-poisoned liver injury and fibrosis in rats]

AIM

To study the actions of salvianolic acid A (SA-A) on liver injury and liver fibrosis.

METHODS

The liver fibrotic rat was made by i.p. injection of CCl4. The model rats were divided into 3 groups treated with SA-A, colchicine (Col), and Salvia miltiorrhiza Bunge (SMB), respectively. Six wk later the rat liver pathology was examined, type I and III collagen in the liver were examined by immunohistochemistical method. Also hydroxyproline (Hyd) and malondialdehyde (MDA) in the liver, alanine aminotransferase (AlaAT), aspartate aminotransferase (AspAT), and albumin (Alb) levels in the serum were measured.

RESULTS

SA-A inhibited serum AlaAT and AspAT activities, decreased MDA and Hyd contents, alleviated liver fibrogenesis, protected deposition of type I and III collagen in liver matrix. The actions of SA-A on liver fibrosis were similar to those of Col and SMB, action of SA-A decreasing MDA was better than that of Col.

CONCLUSION

SA-A has marked effects against liver injury and fibrosis, associated with its anti-lipid peroxidation actions.

[Effect of fuzheng huayu recipe in treating posthepatitic cirrhosis]

This article deals with the effect of Fuzheng Huayu recipe (FZHYR), composed of Semen Persicae, Cordyceps, Radix Salviae Miltiorrhizae, Pollen pini, etc. in treating posthepatitic cirrhosis. 40 patients treated with FZHYR were observed, and another 40 patients in simila condition treated with symptomatic therapy were taken as control. Results showed that the FZHYR could (1) Increase the serum level of albumin and decrease the gamma-globulin; (2) Elevate the lowered plasma branched-chain amino acid/aromatic amino acid ratio; (3) Reduce the raised level of laminin and hyaluronic acid in serum; (4) Escalate the level of CD3+, CD4+, CD4+/CD8+ ratio, NK cells activity and complement C3, lowered the raised level of IgG and IgM in serum. In addition, it could also adjust the anormal change of hormonal secretion. These results suggested that FZHYR has beneficial effect in treating posthepatitic cirrhosis, it acts multifariously and plays important role either in controlling the development of disease or in preventing the complications.

[Observation on the action of extractum semen Persicae on anti-fibrosis of liver]

It was observed that Extractum Semen Persicae acted obviously on hepatic fibrosis induced by CCl4. Through promoting the degradation of collagens type I, II, IV, VI and fibronectin, ESP has proved helpful in markedly reducing the fibrous septa composed of both collagenous and reticular fibers as well as in repairing the structure of hepatic tissues.

[Experimental studies on reconstituted xenograft and its clinical application]

The authors developed a reconstituted bone xenograft (RBX) composed of bovine BMP and the homologous cancellous bone. 36 New Zealand rabbits were used with 15mm defects created in both radii. In group A, 80mg of RBX was implanted into the defect on the left side while the cancellous bone alone was implanted on the right: in group B, the defects in the left and right radius were implanted with RBX plus autologous red marrow and the bioactive ceramic granules, respectively. The healing of the defects was evaluated radiologically, histologically, as well as by tetracycline double-labelling and immunofluorescent techniques within 16 weeks following the surgery. The results suggest that RBX behaves well as a grafting material in filling up and promoting the repair of the defect. Of 38 patients with non-unions and bone defects treated by RBX implantation, 30 were followed up for over 6 months, and all but one had satisfactory bone healing. The authors believe that RBX possesses a strong osteoinductive capacity without evoking immune rejection. Taking into account its unlimited sources, ready availability and simplicity in processing and storage, RBX is expected to have a broad prospect for clinical use.

Evidence for nm23 RNA overexpression, DNA amplification and mutation in aggressive childhood neuroblastomas

Reduced expression of nm23 RNAs/proteins has been associated previously with high tumor metastatic potential. In contrast, we report that regional (state III) and metastatic (stage IV) childhood neuroblastomas exhibit elevated nm23 RNA levels as compared with localized tumors. Elevated neuroblastoma nm23 RNA levels were associated with significant reductions in patient survival in the overall (n = 75) and N-myc non-amplified (n = 61) portion of the cohort. Amplification of the chromosomal nm23-H1 gene was observed in 6/18 stage III and IV tumors; amplification of nm23-H2 was not demonstrated. Genomic amplification of nm23-H1 was associated with increased tumor nm23 RNA expression and reduced patient survival. Single-strand conformational polymorphism (SSCP) analysis was performed on seven neuroblastomas. Minor subpopulations of cDNAs exhibiting altered mobility were apparent in both nm23-H1 and nm23-H2 translated regions of stage III and IV tumors, suggestive of mutations. Confirmation of the SSCP data was provided by direct sequencing of nm23-H2 in a stage IV tumor, revealing a leucine to valine mutation at position 48. The data indicate that molecular alterations to nm23 other than its reduced expression can be associated with tumor aggressiveness, and provide the first evidence for nm23 mutation in a human cancer.

[The study on ultrastructure of gap junction of rat atrial myocytes in primary culture]

We have studied the ultrastructure of gap junction of rat atrial myocytes of primary culture in situ embedded by ultramicrotomy. We observed a kind of gap junction-associated vesicles (GJAV), a kind of cluster of particles which are surrounded by plasma membrane, and a concatenate GJAV complexes (CGJAVC) in some big clusters. We found that both of GJAV and CGJAVC are very near the plasma membrane at the intercellular space, and at the same time they are usually adjacent the assembled GJ. So we infered that they are the pre-body or midproduct of the assembled GJ probably. This article analysed these observes and probed into the process about how to assemble the gap junction.

[Determination of pressure gradient across patent ductus arteriosus with simultaneous continuous wave Doppler and catheterization methods and non-invasive estimation of pulmonary artery pressure]

To evaluate the accuracy of Doppler technique for measuring the pressure gradient (delta P) across patent ductus arteriosus (PDA) with a simplified Bernoulli equation (delta P = 4 V2) and estimating the pulmonary artery pressure (PAP) by subtracting delta P from brachial arterial pressure (BAP) measured with cuff sphygmomanometry, Doppler echocardiography and catheterization (both left and right) were performed simultaneously in 20 patients with PDA. For the values of systolic peak delta P (SPPG), mean delta P (MPG) and end-diastolic delta P (EDPG) determined by both Doppler and catheter, the correlation was excellent (r = 0.99, 0.99, 0.99). Doppler determined SPPG also correlated well with catheter determined peak to peak delta P (P-PPG) (r = 0.97). Comparison between Doppler-derived and catheter measured systolic PAP (SPAP), mean PAP (MPAP) and diastolic PAP (DPAP) also showed high correlation (r = 0.95, 0.98, 0.97). This study demonstrates that Doppler echocardiography is valuable for measurement of delta P across PDA and non-invasive estimation of PAP in patients with PDA.

Isolation and partial characterization of a human amelogenin from a single fetal dentition using HPLC techniques

A strategy based on high pressure liquid chromatography (HPLC) techniques for the isolation or a principal amelogenin molecule from a single human dentition is described. A partial sequence (33 residues) for this 24 kDa amelogenin is presented and related to earlier studies of human 5 kDa tyrosine-rich amelogenin polypeptides (TRAPs). A failure to identify amino acid residue #25 (tryptophan in other amelogenins) suggests that this 24 kDa amelogenin is the progenitor of the human TRAP-2 molecule and provides further support for the possibility of several human amelogenin gene products, generated by splice-junction selection, from the single amelogenin gene in the same individual. Alternatively, multiple amelogenins may arise by expression of both the AMELX and AMELY loci.

[Estimation of systolic pulmonary artery pressure with continuous wave Doppler pressure gradient method: a simultaneous Doppler and catheter correlative study]

To estimate more precisely the systolic pulmonary artery pressure (PASP), continuous wave Doppler pressure gradient method and catheter measurement were performed simultaneously in 85 patients. There were 30 patients with tricuspid regurgitation (TR), 35 with ventricular septal defect (VSD), and 20 with patent ductus arterosus (PDA). For maximal transtricuspid pressure gradient (TRPG) determined by continuous wave Doppler and catheter determined PASP in TR group, the correlation coefficient (r) was as high as 0.99. For Doppler determined PASP (subtracting pressure gradient across PDA from systemic arterial pressure measured by cuff sphygmomanometer) and catheter determined PASP in PDA group, r was 0.95. Doppler determined PASP in VSD group (subtracting pressure gradient across VSD from systemic arterial pressure) also correlated well with catheter determined PASP (r = 0.97). This study demonstrates that continuous wave Doppler pressure gradient method can accurately estimate PASP in patients with TR, PDA, and VSD.

A simple method for direct cloning cDNA sequence that flanks a region of known sequence from total RNA by applying the inverse polymerase chain reaction

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Human amelogenins: sequences of "TRAP" molecules

The extracellular protein matrix of developing enamel includes a major class of proteins, the amelogenins, which are believed to be concerned in regulating enamel biomineralization. Previous studies have shown the amelogenins of the extracellular matrix to be a complex of proline-rich hydrophobic proteins which, it is suggested, arise through posttranslational and postsecretory processing of a primary ameloblast gene product. More recently, it has been shown that the human amelogenin gene is located on both the X and Y chromosomes raising the possibility that polymorphism at the level of the gene may also contribute to the observed complexity of these enamel matrix proteins. To investigate such possible amelogenin polymorphism in developing human dental enamel, individual fractionated by size-exclusion and reversed-phase high pressure liquid chromatography (HPLC). Two tyrosine-rich amelogenin polypeptides (TRAPs) of approximately 5 kDa in size were isolated from an individual human dentition and characterized by automated gas-phase sequencing. These polypeptides were found to be of 42 (TRAP-2) and 44 (TRAP-1) amino acid residues in length; TRAP-2 lacked a carboxy-terminal -Gly-Trp sequence as has previously been described for analogous bovine TRAP molecules. However, residue #25 of the human TRAP-2 sequence was refractory to sequencing, apparently differing from the Trp-25 identified in TRAP-1. These findings suggest (1) two forms of TRAP molecules, differing only by cleavage of a carboxy-terminal dipeptide, are a general feature of human and other mammalian enamel proteins, probably being derived by postsecretory cleavage from the primary extracellular amelogenin; and (2) in human developing enamel four forms of TRAPs may arise either from polymorphism at the level of the gene, or by posttranscriptional alternative splicing of amelogenin mRNAs, coupled with specific post-secretory proteolytic processing.

Amelogenesis in vitro: a model for studies of epithelial postsecretory processing during tissue-specific extracellular matrix biomineralization

The extracellular matrix (ECM) of developing mammalian enamel comprises a complex of unusual epithelial-derived proteins, which appear to function in concert to initiate and propagate tissue-specific biomineralization. Following enamel protein synthesis by ameloblast cells within the enamel organ, the subsequent steps of posttranslational modification, secretion, postsecretory processing and eventual removal of these proteins from forming enamel are largely unknown. To address this issue we have designed studies to investigate the hypothesis that enamel proteins are removed from enamel and translocated into the vasculature as relatively high-molecular-weight components. We examined enamel proteins recovered from serumless medium during prolonged organ culture of mouse capstage mandibular first molars. By 21 days in vitro the tooth crown formed and dentine and enamel biomineralization were apparent. At 31 days, explants retained metabolic activity and the enamel matrix showed extensive transformation. Immunologically identified enamel proteins of 26-18 k Da were produced by cultured tooth organs, translocated from tooth explants to the culture medium, recovered from the medium and then compared to control enamel protein from in vivo preparations. Comparable postsecretory processing of the 26-k Da amelogenin protein was observed in vitro and in vivo. We speculate that the pathway reported in the present studies is comparable to the processing of the enamel protein polypeptides of the maturing enamel which occurs in vivo. The in vitro organ culture model described in this report provides an approach with which to investigate the molecular events associated with epithelial-derived postsecretory processing of ECM molecules associated with tissue-specific biomineralization.

Successful replantation in ten-digit complete amputations

The authors report a case of successful replantation of all fingers in a ten-finger complete amputation. Among the factors responsible for the successful outcome were an adequate number of microsurgically-trained resident surgeons and staff, good organization and supervision by senior staff, emphasis on precision and perseverance in the operative procedures, and postoperative management. Follow-up is 15 months, and the patient now has a pair of functionally and cosmetically good hands.