[Efficacy of venetoclax-based induction regimen in newly diagnosed pediatric acute myeloid leukemia].

Objective: To explore the efficacy of venetoclax-based induction regimen for children with newly diagnosed acute myeloid leukemia (AML). Methods: Children with newly diagnosed AML in Beijing Children's Hospital Affiliated to Capital Medical University and Baoding Hospital Affliliated to Capital Medical University from November 2019 and December 2023 were prospectively included. The patients were divided into DAH group (daunorubicin, cytarabine and homoharringtonine) and VAH group (venetoclax, cytarabine and homoharringtonine) according to induction regimen. The clinical data of the children were collected, the clinical characteristics and induced remission rate between the two groups were compared, and multivariate logistic regression was used to analyze the related factors affecting the induced remission rate. Results: A total of 135 patients were enrolled, including 96 cases in the DAH group (54 males and 42 females), aged [M (Q1, Q3)] 6.4 (3.9, 11.6) years and 39 cases in the VAH group (26 males and 13 females), aged 8.0 (6.2, 13.2) years. Among patients initially diagnosed with low-medium risk AML, the morphologic complete remission rates were 94.7% (18/19) in the VAH group and 84.4% (38/45) in the DAH group, respectively, and the negativity conversion rates of minirnal residual disease (MRD) were 57.9% (11/19) and 46.7% (21/45), respectively, with no statistically difference (all P>0.05). Among patients initially diagnoised with high-risk AML, the morphologic complete remission rates in the VAH group was higher than that in the DAH group [95.0% (19/20) vs 70.6% (36/51), P=0.027], and negativity conversion rates of MRD were 45.0% (9/20) and 33.3% (17/51), respectively, with no statistically difference (P=0.359). The induction regimen (venetoclax, cytarabine and homoharringtonin) was beneficial to morphological remission (OR=0.126, 95%CI: 0.025-0.629). FLT3 mutation was not conducive to morphological remission (OR=5.832, 95%CI: 1.778-19.124) and negative MRD (OR=4.166, 95%CI: 1.396-12.433). Conclusion: Venetoclax-based induction regimen is more effective than traditional chemotherapy regimen for newly diagnosed pediatric AML.

[The diagnostic potential of Golgi protein 73 for cirrhosis in patients with chronic hepatitis C].

Objective: To explore the diagnostic value and model of serum Golgi protein 73 (GP73) in patients with hepatitis C cirrhosis. Methods: 271 cases with chronic hepatitis C virus infection who were treated in the Fifth Medical Center of PLA General Hospital from January 2010 to December 2017 were retrospectively collected as the research objects, including 126 cases with hepatitis and 145 cases with liver cirrhosis. Serum GP73 and liver stiffness measurement (LSM) based on transient elastography test were performed in all patients. Simultaneously, blood routine, liver function, coagulation function and other related indicators were collected. GP73 diagnostic efficiency for liver cirrhosis was evaluated by receiver operating characteristic curve (ROC). GP73 diagnostic value was clarified after comparison with aspartate aminotransferase/platelet ratio index (APRI), FIB-4 index (FIB-4) and LSM. Compensated hepatitis C virus-related cirrhosis diagnostic model based on serological index was established by logistic regression analysis. Results: The area under the receiver operating characteristic curve (AUC) of GP73, LSM, FIB-4 and APRI in the diagnosis of compensated hepatitis C virus-related cirrhosis were 0.923, 0.839, 0.836 and 0.800 respectively, and GP73 had the best diagnostic efficiency (P <0.001). LSM and GP73 combined use had improved the diagnostic sensitivity of cirrhosis to 97.24%. Multivariate logistic regression analysis revealed that GP73, age, and platelets were independent predictors of cirrhosis.Compensated hepatitis C virus-related cirrhosis diagnostic model (GAP) was established based on the result: LogitP=1/[1+exp(6.145+0.013×platelet-0.059×age-0.059×GP73)].AUC model for diagnosing compensated liver cirrhosis was 0.944, and the optimal cut-off value was 0.56, with sensitivity and specificity of 84.03% and 92.06%, respectively, and the diagnostic efficiency of this model was better than that of APRI, FIB-4, LSM and GP73 alone (P<0.05). Conclusion: GP73 is a reliable serum biomarker for the diagnosis of compensated hepatitis C virus-related cirrhosis. The GAP diagnostic model based on GP73, platelet count, and age can further improve the diagnostic efficiency and help to diagnose patients with compensated hepatitis C virus-related cirrhosis.

[Analysis on the epidemic characteristics and genetic characteristics of varicella in Beijing from 2019 to 2021].

The reported incidence of varicella in Beijing from 2019 to 2021 were 63.8/100 000, 32.2/100 000 and 38.6/100 000, respectively. There were two VZV epidemics in Beijing each year, one peaked in May and the other in November. However, the first VZV epidemic almost disappeared in 2020. Among the cases involved in the varicella outbreaks in school, the proportion of the students with no history of vaccine immunization, 1 dose of immunization and 2 doses of immunization were 33.12%, 44.79% and 22.08%, respectively. The major body of VZV breakthrough cases was children aged 6-14 years (523/755, 69.27%). The proportion of moderate- or severe-rash were 55.32%, 39.06%, 29.96% in the three groups of cases with no immunization history, 1 dose of immunization and 2 doses of immunization, respectively (P<0.001). A total of 1 089 varicella samples were collected, and 837 (76.86%) were confirmed to be PCR-positive for VZV and were identified as VZV wild strains. 311 VZV strains were sequenced successfully, and 307 strains were clade 2 (98.72%), 1 clade 3 (0.32%) and 3 Clade 5 (0.96%). Compared with the representative strains, the nucleotide similarities of ORF22 fragments were between 99.4% and 100%, and amino acid similarities were between 99.4% and 100%.

New α-Emitting Isotope

A new α-emitting isotope ^{214}U, produced by the fusion-evaporation reaction ^{182}W(^{36}Ar,4n)^{214}U, was identified by employing the gas-filled recoil separator SHANS and the recoil-α correlation technique. More precise α-decay properties of even-even nuclei ^{216,218}U were also measured in the reactions of ^{40}Ar, ^{40}Ca beams with ^{180,182,184}W targets. By combining the experimental data, improved α-decay reduced widths δ^{2} for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N=126 are deduced. Their systematic trends are discussed in terms of the N_{p}N_{n} scheme in order to study the influence of proton-neutron interaction on α decay in this region of nuclei. It is strikingly found that the reduced widths of ^{214,216}U are significantly enhanced by a factor of two as compared with the N_{p}N_{n} systematics for the 84≤Z≤90 and N<126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the π1f_{7/2} and ν1f_{5/2} spin-orbit partner orbits, which is supported by the large-scale shell model calculation.

An efficient in vitro regeneration system from different wild apple (Malus sieversii) explants.

BACKGROUND: Wild apple, Malus sieversii, is an endangered species and a valuable genetic resource that requires a variety of conservation techniques. This study aimed to investigate the influence of different concentrations of hormones on wild apple regeneration from leaf and stem explants to establish an optimal regeneration system. RESULTS: Leaves and stems derived from seedlings were cultured on several media supplemented with various concentrations of thidiazuron (TDZ) or 6-benzylaminopurine (BA) in different combinations with 1-naphthaleneacetic acid (NAA). The results showed that the most efficient shoot formation media (35% and 90%) were MS medium containing 4.0 mg L-1 TDZ and 1.0 mg L-1 NAA for leaf explants and MS medium containing 1.0 mg L-1 BA without NAA for stem explant. MS medium supplemented with 0.4 mg L-1 BA and 0.1 mg L-1 NAA (for shoot multiplication) and 1/2 MS + 0.1 mg L-1 NAA + 1.5% sucrose (for rooting) were effective media. Shoot regeneration from leaf explants was the most effective when the explants were placed abaxial side down onto the medium and were subjected to a pre-treatment of 3 weeks in darkness. CONCLUSIONS: An optimized regeneration system for M. sieversii that allowed regeneration within 2-3 months developed. The protocol developed herein can be used in large-scale clonal propagation for the conservation of wild apple, M. sieversii.

[Exploring the mechanism of liver enzyme abnormalities in patients with novel coronavirus-infected pneumonia].

Objective: To explore and analyze the possible mechanism of liver injury in patients with coronavirus disease 2019 (novel coronavirus pneumonia, NCP). Methods: The correlation between ALT, AST and other liver enzyme changes condition and NCP patients' disease status reported in the literature was comprehensively analyzed. ACE2 expression in liver tissue for novel coronavirus was analyzed based on single cell sequencing (GSE115469) data. RNA-Seq method was used to analyze Ace2 expression and transcription factors related to its expression in liver tissues at various time-points after hepatectomy in mouse model of acute liver injury with partial hepatectomy. t-test or Spearman rank correlation analysis was used for statistical analysis. Results: ALT and AST were abnormally elevated in some patients with novel coronavirus infection, and the rate and extent of ALT and AST elevation in severe NCP patients were higher than those in non-severe patients. Liver tissue results of single cell sequencing and immunohistochemistry showed that ACE2 was only expressed in bile duct epithelial cells of normal liver tissues, and very low in hepatocytes. In a mouse model of acute liver injury with partial hepatectomy, Ace2 expression was down-regulated on the first day, but it was elevated up to twice of the normal level on the third day, and returned to normal level on seventh day when the liver recovered and hepatocyte proliferation stopped. Whether this phenomenon suggests that the bile duct epithelial cells with positive expression of Ace2 participate in the process of liver regeneration after partial hepatectomy deserves further study. In RNA-Seq data, 77 transcription factors were positively correlated with the expression of Ace2 (r > 0.2, FDR < 0.05), which were mainly enriched in the development, differentiation, morphogenesis and cell proliferation of glandular epithelial cells. Conclusion: We assumed that in addition to the over activated inflammatory response in patients with NCP, the up-regulation of ACE2 expression in liver tissue caused by compensatory proliferation of hepatocytes derived from bile duct epithelial cells may also be the possible mechanism of liver tissue injury caused by 2019 novel coronavirus infection.

[Establishment and preliminary application of serum Golgi protein 73 based noninvasive diagnostic model for compensated stage hepatitis B cirrhosis].

Objective: To establish and evaluate diagnostic efficacy and applicability of serum Golgi protein (GP) 73 based non-invasive diagnostic model with other conventional serological indicators for compensated stage hepatitis B cirrhosis. Methods: 666 cases with chronic hepatitis B (CHB) who had visited to the Fifth Medical Center of People's Liberation Army General Hospital from January 2010 to December 2017 were selected as the study subjects, and were classified according to compensated stage cirrhosis into clinical and pathological diagnosis group based on whether or not the liver histological examination was performed. A diagnostic model of compensated stage hepatitis B cirrhosis in the clinical diagnosis group was established. The current clinically used diagnostic model of liver cirrhosis, aspartate aminotransferase/platelet ratio index (APRI), fibrosis index (FIB)-4 and liver stiffness measurement (LSM) were compared. Eventually, the diagnostic model was verified step by step by pathological diagnosis group. Results: The area under the receiver operating characteristic curve (AUC) of GP73 and APRI, FIB-4, and LSM for cirrhosis patients in the clinical diagnosis group were 0.842, 0.857, 0.864, and 0.832, respectively. The diagnostic efficiency of the four indicators were of similar (P value > 0.05). A diagnostic model of compensated stage hepatitis B cirrhosis (GAPA) using logistic regression analysis was established: LogitP = 1/ [1 + exp (1.614-0.054 × GP73-0.045 × Age + 0.030 × PLT-0.015 × ALP)]. The AUC of the model was as high as 0.940 and the optimal cut-off value were 0.41. The corresponding diagnostic sensitivity and specificity were 0.92 and 0.82, respectively. The diagnostic efficiency was better than that of APRI, FIB-4, LSM and GP73 alone (P < 0.05). The AUC of GAPA was 0.877 in the pathological diagnosis group, which was similar to the diagnostic efficacy of LSM (0.891) and FIB-4 (0.847) (P > 0.1), but still superior to that of APRI (0.811) and GP73 alone (0.780) (P < 0.001). Conclusion: GAPA, a diagnostic model for compensated stage hepatitis B cirrhosis established in this study, has a good diagnostic efficacy in both the clinical and pathological diagnosis group, and has certain auxiliary diagnostic value in the areas where resources are relatively scarce or where LSM has not been developed.

Performance of Xpert® MTB/RIF and Determine™ TB-LAM Ag in HIV-infected adults in peri-urban sites in Zambia.

SETTING: Peri-urban health facilities providing HIV and TB care in Zambia. OBJECTIVE: To evaluate 1) the impact of Xpert® MTB/RIF on time-to-diagnosis, treatment initiation, and outcomes among adult people living with HIV (PLHIV) on antiretroviral therapy (ART); and 2) the diagnostic performance of Xpert and Determine™ TB-LAM Ag assays. DESIGN: Quasi-experimental study design with the first cohort evaluated per standard-of-care (SOC; first sputum tested using smear microscopy) and the second cohort per an algorithm using Xpert as initial test (intervention phase; IP). Xpert testing was provided onsite in Chongwe District, while samples were transported 5-10 km in Kafue District. TB was confirmed using mycobacterial culture. RESULTS: Among 1350 PLHIV enrolled, 156 (15.4%) had confirmed TB. Time from TB evaluation to diagnosis (P = 0.018), and from evaluation to treatment initiation (P = 0.03) was significantly shorter for IP than for SOC. There was no difference in all-cause mortality (7.0% vs. 8.6%). TB-LAM Ag showed higher sensitivity with lower CD4 cell count: 81.8% at CD4 < 50 cells/mm3 vs. 31.7% overall. CONCLUSION: Xpert improved time to diagnosis and treatment initiation, but there was no difference in all-cause mortality. High sensitivity of Determine TB-LAM Ag at lower CD4 count supports increased use in settings providing care to PLHIV, particularly with advanced HIV disease.

[Advances in the p75 neurotrophic factor receptor in stomatology].

The p75 neurotrophic factor receptor is a low affinity receptor for neurotrophic factors and plays an important role in nerve growth, development and function integrity. It is closely related to dental development, oral and maxillofacial tumor, nerve repair and tissue engineering. It shows good prospect for application. In this paper, the research progress of p75 neurotrophic factor receptor in Stomatology is reviewed.

Effect of Variable Temperature on the Development of Eucryptorrhynchus brandti (Coleoptera: Curculionidae).

Temperature is one of the most important abiotic factors that influences the development and growth of insects. We investigated the effect of temperature on the development of the weevil Eucryptorrhynchus brandti (Harold). The developmental zeros and effective accumulated temperatures for different developmental stages of E. brandti were estimated under variable temperatures in the laboratory. We observed that the developmental zeros of eggs, larvae, and pupae were 15.27 °C, 20.86 °C, and 14.04 °C, respectively, and the effective accumulated temperatures were 81.46 °C·d, 293.76 °C·d, and 127.76 °C·d, respectively. The rate of development increased as the temperature increased within a particular temperature range, and temperatures from 30 °C to 31 °C were particularly suitable for E. brandti rearing. Based on these results, we may be able to predict the occurrence of E. brandti, providing a reference for physical control measures targeting adults to effectively reduce oviposition and minimize population expansion.

[Expression of p75 neurotrophin receptor during the mineralization of ectomesenchymal stem cells in vitro].

OBJECTIVE: To investigate the mineralized capacities of ectomesenchymal stem cells (EMSC) from facial process of Sprague Dawley(SD) rat embryo of different age in vitro and the expression of p75 neurotrophin receptor(p75NTR) in this process. METHODS: The stem cell surface antigens of EMSC from 12.5 d, 15.5 d and 18.5 d SD rat embryonic facial process were tested by flow cytometry technology. E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were incubated under mineralization induction and analysed by alkaline phosphatase(ALP) staining on day 7(d7) and alizarin red staining on day 21(d21). Expression changes of Runt-related transcription factor-2(RUNX2), collagen Ⅰ (Col Ⅰ) and p75NTR in each group were measured using Western blotting and real time(RT)-PCR on day 0(d0), day 7(d7), day 14(d14) and day 21(d21). RESULTS: The expression of the special substances CD29, CD146 and p75NTR in E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were positive, and the expression of CD45 was negative. The expression level of p75NTR in E18.5 d EMSC(84.04%) was much higher than that of E12.5 d EMSC (22.53%) and E15.5 d EMSC(81.43%). The mineralized capacities of E18.5 d EMSC was stronger than that of E12.5 d EMSC and E15.5 d EMSC. The higher expression of RUNX2, Col Ⅰ in E18.5 d EMSC(RUNX2: 1.92±0.20, Col Ⅰ: 1.85±0.66) was found compared with E12.5 d EMSC(RUNX2: 0.38±0.02, Col Ⅰ: 0.33± 0.94) and E15.5 d EMSC(RUNX2: 0.72±0.22, Col Ⅰ: 0.64±0.07) (P<0.05), and p75NTR in the E18.5 d EMSC experimental group(E12.5 d: 0.79±0.23, E15.5 d: 0.84±0.29, E18.5 d: 1.35±0.22) was significantly higher than the in control group(E12.5 d: 0.42±0.12, E15.5 d: 0.43±0.13, E18.5 d: 0.48±0.15)(P<0.05). RT-PCR further proved the results of the Western blotting. CONCLUSIONS: p75NTR participated in the mineralization differentiation of EMSC. E18.5 d EMSC had a higher expression of p75NTR and stronger mineralization capacity and was the ideal engineering seed cells.

Detection, differentiation, and VP1 sequencing of duck hepatitis A virus type 1 and type 3 by a 1-step duplex reverse-transcription PCR assay.

Duck hepatitis A virus (DHAV) is an infectious pathogen causing fatal duck viral hepatitis in ducklings. Although both the inactivated vaccines and live attenuated vaccines have been used to protect ducklings, DHAV-1 and DHAV-3 still cause significant serious damage to the duck industry in China and South Korea. For rapid detection, differentiation, and epidemic investigation of DHAV in China, a genotype-specific 1-step duplex reverse-transcription (RT) PCR assay was established in this study. The sensitivity and specificity of the developed RT-PCR assay was evaluated with nucleic acids extracted from 2 DHAV reference strains, and 9 other infectious viruses and bacteria. The genotype-specific primers amplified different size DNA fragments encompassing the complete VP1 gene of the DHAV-1 or DHAV-3. The assay detected the liver samples collected from experimentally infected ducklings and dead ducklings collected from different regions of China. Sequence analysis of these DNA fragments indicated that VP1 sequences of DHAV-1 can be used to distinguish wild type and vaccine strains. The phylogenetic analysis of VP1 sequences indicated that the developed RT-PCR assay can be used for epidemic investigation of DHAV-1 and DHAV-3. The developed RT-PCR assay can be used as a specific molecular tool for simultaneous detection, differentiation, and sequencing the VP1 gene of DHAV-1 and DHAV-3, which can be used for understanding the epidemiology and evolution of DHAV.

Meta-analysis on the efficacy and tolerability of the augmentation of antidepressants with atypical antipsychotics in patients with major depressive disorder

We assessed the efficacy and tolerability of the augmentation of antidepressants (ATDs) with atypical antipsychotics (AAPs) to treat patients with major depressive disorder. A retrograde study to identify relevant patient data included databases of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Database of Abstracts of Reviews of Effects. Data from 17 trials, involving 3807 participants, were identified. The remission rate (RR) and overall response rate (ORR) of adjunctive treatment with AAPs were significantly higher than placebo treatment: RR=1.90 (95%CI=1.61-2.23, z=7.74, P<0.00001) and ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001). We found that the short-term (4 weeks) treatment [ORR=1.70 (95%CI=0.98-2.95, Z=1.89, P=0.06)] was significantly different from the long-term (6-12 weeks) treatment [ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001)]. No significant difference in ORR was observed between groups with or without sedative drugs. The discontinuation rate due to adverse effects was higher for adjunctive treatment with AAPs: ORR=3.32 (95%CI=2.35-4.70, z=6.78, P<0.00001). These results demonstrate that the augmentation of ATDs with AAPs (olanzapine, quetiapine, aripiprazole, and risperidone) was more effective than a placebo in improving response and remission rates, although associated with a higher discontinuation rate due to adverse effects.

Meta-analysis on the efficacy and tolerability of the augmentation of antidepressants with atypical antipsychotics in patients with major depressive disorder.

We assessed the efficacy and tolerability of the augmentation of antidepressants (ATDs) with atypical antipsychotics (AAPs) to treat patients with major depressive disorder. A retrograde study to identify relevant patient data included databases of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Database of Abstracts of Reviews of Effects. Data from 17 trials, involving 3807 participants, were identified. The remission rate (RR) and overall response rate (ORR) of adjunctive treatment with AAPs were significantly higher than placebo treatment: RR=1.90 (95%CI=1.61-2.23, z=7.74, P<0.00001) and ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001). We found that the short-term (4 weeks) treatment [ORR=1.70 (95%CI=0.98-2.95, Z=1.89, P=0.06)] was significantly different from the long-term (6-12 weeks) treatment [ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001)]. No significant difference in ORR was observed between groups with or without sedative drugs. The discontinuation rate due to adverse effects was higher for adjunctive treatment with AAPs: ORR=3.32 (95%CI=2.35-4.70, z=6.78, P<0.00001). These results demonstrate that the augmentation of ATDs with AAPs (olanzapine, quetiapine, aripiprazole, and risperidone) was more effective than a placebo in improving response and remission rates, although associated with a higher discontinuation rate due to adverse effects.

A unique surface-initiated property of nanoparticles and application for the synthesis of hybrid organic-inorganic nanoparticles.

We report a unique property of nanoparticles to initiate acrylic acid and acrylamide solution polymerization under low air pressure conditions. This property could be applied to synthesize a wide variety of hybrid organic-inorganic nanoparticles, which hold great promise for use in nanophotonics, catalysis, and medical applications.

Clay pica has no hematologic or metabolic correlate in chronic hemodialysis patients.

OBJECTIVE: Clay pica is a form of compulsive ingestion of non-nutritive substances frequently practiced by dialysis patients. Its consequences are unknown. In this study, we evaluated the effect of regular consumption of clay on hematologic and metabolic profiles in hemodialysis patients. DESIGN: A prospective, case-control study with use of structured questionnaire. SETTING: Free-standing hemodialysis units. PATIENTS: One hundred thirty-eight patients on hemodialysis for at least 12 months were interviewed. Thirteen of 138 (9.4%) confessed to clay pica. Ten randomly selected patients with no history of pica served as control. INTERVENTION: Average of all laboratory profiles and interdialytic weight gain (IDWG) over a 3-month period were recorded. Assay of the aluminum (Al), silica (Si), and iron (Fe) content of commercially purchased clay was performed. MAIN OUTCOME MEASURE: Comparison of laboratory profiles and IDWG between cases and control. Estimation of the daily consumption of Al, Fe, and Si from clay and their relationship to the laboratory profiles. RESULTS: There was no statistically significant difference in the levels of Al, albumin, calcium, ferritin, hematocrit, iron saturation, phosphorus, and IDWG between pica cases and control. Iron was significantly higher in pica patients (13.0 +/- 7.9 micromol/L v 7.5 +/- 2.5 micromol/L, P =.04), but potassium was higher among control than pica cases (4.9 +/- 0.7 mmol/L v 4.4 +/- 0.6 mmol/L, P =.07). Estimated metal exposure from daily clay consumption per patient were: Al (1-2 mg), Fe (11-23.5 mg), and Si (2-4.5 g). Multivariate logistic regression analysis failed to show any association between clay consumption and nutrition, anemia, or mineral metabolism (R(2) = 0.0, P =.79). CONCLUSION: Clay pica does not appear to be detrimental to the hematologic and metabolic milieu of hemodialysis patients. The practice should, however, be discouraged, because of potential for ingestion of unknown substances, and reported potential for gastrointestinal complications.

Actin filament bundles in cortical fiber cells of the rat lens.

The distribution and organization of actin filament bundles were studied in cortical fiber cells of rat lenses at various ages (3 days to 2.5 months old), using thin-section electron microscopy, immunocytochemistry and immunoblotting. Electron microscopy showed that actin bundles were regularly found along cortical fiber cell membranes of the lens at all ages studied. The actin bundles were commonly arranged in three distinct units, one bundle in each fiber cell, located at the intersections where three hexagonal fiber cells meet as seen in cross sections. These actin bundles were approximately 150 nm in diameter and were composed of 7-nm small filaments. They were aligned parallel to the long axis of fiber cells as judged by both cross and longitudinal sections. The outside border of each bundle was always surrounded by a zone of 10-nm intermediate filaments which have the same orientation as that of the actin bundles. In longitudinal sections, elongated actin bundles were always parallel to the cell membranes. A number of individual actin bundles sometimes were found to form a chain with periodic short intervals. In addition, actin bundles were frequently associated with adherens junctions near the intersections and other regions of fiber cell membranes. By immunoelectron microscopy, we demonstrated that these filament bundles indeed contained actins. By rhodamine-phalloidin labelling, we found that labeled actin bundles appeared as large, distinct dots at the corners of hexagonal fiber cells in all ages studied. In addition, non-bundle F-actins were labeled preferentially along the cell membranes of the short sides of hexagonal fiber cells. This resulted in a unique zigzag pattern of actin labeling commonly seen in the cortical fiber cells of a mature rat lens. Finally, we showed that alpha-actinin was associated with the actin bundles in the fiber cells by immunofluorescent double labeling and immunoblotting. It is suggested that this unique arrangement of actin bundles in fiber cells may provide a stabilizing structure for forming a sharp angle at each corner of fiber cells, thereby the hexagonal shape of the cells can be maintained.

Porous hydroxyapatite reinforced with collagen protein.

Porous hydroxyapatite (HAP) with certain porosity and pore size was prepared, and incorporated with bovine collagen protein. The composition and structure of the HAP was confirmed by X-Ray Diffraction (XRD) and ICP. Scanning Electron Microscopy (SEM), mechanical tests and in vitro degradation were performed. Collagen protein with low antigenicity was obtained from bovine tendon by enzyme digestion, and was then forced to fill in the HAP matrix to form composites. Scanning Electron Microscopy (SEM), Mechanical tests and in vitro degradation were performed. The test results show that first, HAP thus made has specific pore size and directions; second, mechanical properties of the composites have been markedly improved; third, the in vitro degradation rate of the composite is almost the same as and mainly controlled by the degradation rate of collagen.