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Biomedical subjects

L Hu

Publications and source records attributed to L Hu.

At least 109 records · Page 6Linked to original sources
PubMed1997

Perinatal lethality and multiple craniofacial malformations in MSX2 transgenic mice.

MSX2 is a homeodomain transcription factor that has been implicated in craniofacial morphogenesis on the basis of its expression pattern during mouse development and the finding of a missense mutation (P148H) in humans affected with Boston-type craniosynostosis. We have generated transgenic mice carrying a 34 kb DNA fragment encompassing a human MSX2 gene encoding either wild-type or mutant (P148H) MSX2. Inheritance of either transgene resulted in perinatal lethality and multiple craniofacial malformations of varying severity, including mandibular hypoplasia, cleft secondary palate, exencephaly, and median facial cleft, which are among the severe craniofacial malformations observed in humans. Transgenic mice also manifested aplasia of the interparietal bone and decreased ossification of the hyoid. Transgene-induced malformations involved cranial neural-crest derivatives, were characterized by a deficiency of tissue, and were similar to malformations associated with embryonic exposure to ethanol or retinoic acid, teratogens that cause increased cell death. Together with previous observations implicating MSX2 expression in developmentally-programmed cell death, these results suggest that wild-type levels of MSX2 activity may establish a balance between survival and apoptosis of neural crest-derived cells required for proper craniofacial morphogenesis.

Animals↗
PubMed1997

In search of the harmonious face: Apollo revisited, with an examination of the indications for retrograde maxillary displacement.

A historical review of our perception of facial flatness and convexity and what constitutes "a pleasing face," both in North America and internationally, is provided. Attractive faces may range from slightly flat ("Apollonian") to mildly bimaxillary protrusive, but marked deviations in either direction, from the dish face to extreme bimaxillary protrusion, constitute a deformation and warrant combined orthodontic and surgical treatment. Technical aspects of segmental and total maxillary setback are presented, along with four representative cases.

Asian People↗
PubMed1997

Role of nitric oxide in the arterial pressure and renal adaptations to long-term changes in sodium intake.

The goals of this study were to determine whether long-term nitric oxide (NO) synthesis inhibition in dogs results in an increase in the sodium sensitivity of arterial pressure and whether changes in plasma renin activity or the plasma concentrations of arginine vasopressin (AVP) and aldosterone play an important role in this hypertension. Studies were conducted in a control group and groups that received NO inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) at 10 or 25 microg x kg(-1) x min(-1). Each group was challenged with normal, low, and high sodium intake for periods of 5 days each. Urinary nitrate + nitrite excretion (UNOx) more than doubled in the control group during high sodium intake. In both L-NAME groups, UNOx decreased significantly, there was a hypertensive shift in the relation between urinary sodium excretion and arterial pressure, and urinary sodium excretion remained normal even in the high-sodium intake period. L-NAME infusion did not change the sodium sensitivity of arterial pressure or plasma renin activity, plasma aldosterone, and plasma AVP. In conclusion, the data suggest that, in dogs, increases in NO synthesis are not necessary to excrete a chronic sodium load, and decreases in NO do not increase the sodium sensitivity of arterial pressure.

Acclimatization↗
PubMed1997

[Effects of increasing perilymph calcium levels on various cochlear potentials].

In the present study, we examined the effects of increasing perilymph calcium (12.20 mmol/L) on guinea pig cochlear functions. The results demonstrated that high calcium perilymphs suppressed the magnitude of compound action potential of auditory nerves (CAP) with a prolongation of N1-peak delay at a constant intensity (90 dB SPL), but not of cochlear microphonics (CM). High calcium perilymph didn't change general endocholear potential (G-EP), while reduced the rapid change of EP at on and off set of 115dB SPL white noise exposure. Furthermore the value of negative potential (N-EP) induced by anoxia was decreased because of high calcium perfusions. Machanisms of these effects were discussed.

Action Potentials↗
PubMed1997

[A preliminary report of microlamellar keratectomy for correction of high myopia].

OBJECTIVE: To evaluate the preliminary results of high myopia corrected by microlamellar keratectomy (MLK). METHODS: 73 eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00 to -32.00 D (mean -18.45 +/- 6.18 D). All the operations were performed with a special apparatus made in America for MLK. RESULTS: At 6 months after surgery, in the 73 eyes with complete data, all the uncorrected visual acuity and corrected visual acuity were betterthan or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). The correction of refraction in 63 eyes (86.30%) was within +/- 4.00 D of the intended correction. No severe complications occurred during and after operation. The postoperative status of refraction was stable. CONCLUSIONS: MLK is effective in high myopia treatment and has some special advantages compared with radial keratotomy, photorefractive keratectomy, automated lamellar keratoplasty and excimer laser in situ keratomileusis. But the procedure is influenced by several factors, and the predictability of this procedure is merely fair. The authors suggest that this kind of procedure be done with excellent microsurgery equipment, microsurgical skills and much more clinical experiences in managing corneal disorders.

Adolescent↗
PubMed1997

[Immunogenecity of expressed protein p68 from recombinant plasmid rpDJt in L. interrogans serovar lai].

There are two types of infection caused by pathogenic microorganisms, intracellular infection and intercellular infection. Infection of pathogenic leptospira is an intercellular infection. The immunological reaction of host to intercellular infection is unique. The potential immunogen of an expressed protein should meet three criteria: it can be degraded (by antigen-present cells in the host); it should have antigenic epitope which can be recognized by specific antibodies and have at least one epitope that can be recognized by an MHC II protein and T cell receptor. In this study we report the cloning of an L. interrogans protein in plasmid rpDJt and the immunogencity of the expressed protein derivative. A genomic library of L. interrogans serovar lai strain 017 was constructed with the plasmid vector pUC18. Recombinant plasmids, designated pDJH2 and pDJ8 were screened from the bank. EcoRI-inserted fragment of 1. 9 kb recombinant DNA of pDJH2 was ligated into T7 RNA polymerase/promoter vectors (pT7-7). Then they were transformed into E. coli JM109 (De3), one of subclones, designated rpDJt was achieved. SDS-PAGE showed that the molecular weights of expression proteins were 68 kd and 23 kd respectively, designated p68 and p23. Purifying and isolating p68 and p23, we separated them from SDS-Polyacrylamide gels by using Side-Strip method. After fragmenting and electroeluting, p68 and p23 were injected into guinea pigs and rabbits. An extremely strong immune response to p68 was obtained since an anti-p68 antibody response could be detected to a dilution 1:524,288 (guinea pigs) and 1:262,144 (rabbits) by ELISA while anti-P23 antibody being 1:1024 (the same to guinea pigs and rabbits). The results of improved MTT and conA 3HTdR transformation methods showed the activities and proliferation of Th-cells were increased in guinea pigs after p68 immunization (IL-6, 83.25 IU/ml, IL-2, 28.75 IU/ml; RPI, 2.04, SI, 65.62%) Thlymphocyte existed in two subclasses, the Th1- and Th2-cells. A major role of Th2-cells is to "help" B-cells differentiate, replicate, and secrete antibody. The properties of these interactions explain why p68 makes good antigen and p23 does not. The antigens responsible for eliciting the production of protective antibodies are not known; however, several outer membrane proteins on L. interrogans are candidates for vaccine. Our results suggest that expresion protein p68 from recombinants (rpDJt) may be a candidate for gene engineered subunit vaccine for Leptospirosis.

Animals↗
PubMed1997

[Construction of genomic library of L. interrogans serovar lai using lambda gt11 as the vector and a study of recombiant plasmid pDL121].

A genomic library of L. interrogans serovar lai strain 017 has been constructed using lambda gt11 as the vector. DNA was partially digested by two blunt-end restriction enzymes, then methylated with EcoR I methylase; after EcoR I linker was added to the DNA, the linker-ended DNA was ligated to the dephosphorylated EcoR I digested lambda gt11 arms. The recombined DNA was packaged in vitro, and used to transduct E. coli Y1090 for amplification. There were 2.1 x 10(6) recombinant bacteriophages as recognized by their ability to form white plaques plated on Lac host in the presence of both IPTG and X-Ga1. A positive clone, designated lambda DL12, was screened with a rabbit anti-serum against L. interrogans serovar lai from the genomic library. The DNA from lambda DL12 was subcloned into plasmid pUC18. A recombinant (designated as pDL121) was obtained. SDS-PAGE analysis indicated that a 23 kd was expressed in E. coli JM 103 harboring pDL121. Western blotting analysis showed that a specific protein band molecular weight of 23 kd could be recognized by the rabbit antiserum against L. interrogans serovar lai strain 017.

Cloning, Molecular↗
PubMed1997

[Allogeneic bone marrow transplantation for a patient with malignant histiocytosis].

OBJECTIVE: To observe the efficacy and side effects of allogeneic bone marrow transplantation (allo-BMT) in the treatment of malignant histiocytosis (MH). METHODS: After conditioning with chemotherapy and total body irradiation, HLA-A, B, DR, DQ compatible allo-BMT was performed in a patient with MH. RESULTS: DNA fingerprinting showed engraftment on day 22, bone marrow aspiration showed hypercellularity on day 50, and no abnormal cell was found. The patient developed acute graft-versus-host disease ( II degrees) on day 40 and herpes zoster 6 months post-transplantation, and the patient has survived disease-freely for 24 months after allo-BMT. CONCLUSION: This is the first report of treatment of MH with allo-BMT in China, showing that allo-BMT may significantly prolong the survival of MH.

Adult↗
PubMed1997

A new direction for cleft palate research.

Successful outcomes in the treatment of complete unilateral cleft-lip and palate (CUCL/P) and complete bilateral cleft lip and palate (CBCLP) are not obtained universally, despite significant improvements in surgical techniques over the past three decades. In particular, deficient palatal growth may occur even when expert surgical treatment is rendered. The factors which contribute most significantly to unfavorable growth outcomes remain obscure.

Journal Article↗
PubMed1997

Isotypic antibody responses of a population in an endemic area of schistosomiasis japonica and their epidemiologic significance.

The present study was designed to explore if there exists a correlation between predominant isotype-defined antibody levels and reinfection in low age groups of the population in an endemic area of schistosomiasis japonica in China. One hundred and thirty-eight individuals aged 3-25 years old were selected for serological investigations including the levels of IgG, IgG4, IgM and IgE, detected by ELISA with soluble egg antigen and soluble adult worm antigen. Results show that age is a determinant for SEA-specific IgG, IgG4, and IgE, and SWA-specific IgG and IgG4 antibody levels, which increased with age, and that SEA- and SWA- specific IgG4 antibody levels are risk factors of reinfection, ie, the risk of reinfection occurrence of the population with high level of SEA or SWA-specific IgG4 is 2.83 or 2.40 times, respectively, that with low level of SEA or SWA-specific IgG4, suggesting that in the endemic area of schistosomiasis japonica, there exists a possibility that in the population aged 3-25 years, SEA and SWA-specific IgG4 antibodies mediate a blocking immunity response.

Adolescent↗
PubMed1997

Detection of differentially expressed genes in methylnitrosourea-induced rat mammary adenocarcinomas.

In this study, altered gene expression in five methylnitrosourea (MNU)-induced rat mammary adenocarcinomas was investigated using a newly developed competitive cDNA library screening assay. In order to detect the differentially expressed cDNA transcripts, three cDNA libraries (rat mammary, rat liver, and rat kidney) with over 18,000 clones were differentially screened with competing normal and neoplastic mammary cDNA probes. Ninety-eight clones indicated by competitive hybridization to be differentially expressed in tumors were verified by dot-blot hybridization analysis. Of these clones, 45 were found to be overexpressed while 53 were underexpressed in tumors. Forty-five of the confirmed clones were further analyzed by single-pass cDNA sequence determination. Four clones showed homology with cytochrome oxidase subunit I, polyoma virus PTA noncoding region, cytoplasmic beta-actin, and mouse secretory protein containing thrombospondin motifs. Further investigation into the potential roles of these identified genes should contribute significantly to our understanding of the molecular mechanism(s) of rat mammary tumorigenesis.

Adenocarcinoma↗
PubMed1997

Microlamellar keratectomy for correction of high myopia.

OBJECTIVE: To evaluate the preliminary results of high myopia correction by microlamellar keratectomy (MLK). METHODS: Seventy-three eyes of 43 patients with high myopia were treated by MLK. The preoperative refraction ranged from -7.00D to -32.00D (mean -18.45D +/- 6.18D). All the operations were performed with the special apparatus for MLK. RESULTS: At 6 months after surgery, in the 73 eyes except 2 with new other symptoms, all the uncorrected visual acuity and corrected visual acuity were better than or equal to their preoperative ones respectively. Uncorrected visual acuity was better than or equal to the preoperative corrected visual acuity in 51 eyes (71.83%). No severe complications occurred during and after operation. The postoperative refractive status was stable. CONCLUSIONS: MLK is effective to reduce high myopia and has some special advantages as compared with radial keratotomy (RK), photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK). But influenced by several factors, the predictability of this procedure is merely fair. It is suggested that this kind of procedure must be done with excellent microsurgery equipments, microsurgical skills and much more clinical experience of managing corneal disorders.

Adolescent↗
PubMed1997

[Clinical and experimental study for allergic rhinitis with treatment of biminkang mixture].

OBJECTIVE: To observe the efficacy of Biminkang in treating allergic rhinitis. METHODS: One hundred and sixty-four cases of allergic rhinitis were treated with the Chinese medicine Biminkang mixture mainly consisted of the Kazak folk herb Artemisia rupestis L. and in 52 cases of allergic rhinitis were treated as the control with the patent medicine Biyankang. RESULTS: The total effective rates in both groups are 93.9% and 69.2% respectively. After stopping the medications, the recurrence rates were 46.8% and 87.1%. Biminkang was better than Biyankang in short or long term of effectiveness (P < 0.01). Pharmacological study demonstrated Biminkang played a significant role of resisting histamine, inhibiting allergic reaction I and stabilizing cell membrane of mastocyte. CONCLUSION: Biminkang mixture is an effective drug in treating allergic rhinitis.

Adolescent↗
PubMed1996

Overexpression of c-Fos induces apoptosis of CD43+ pro-B cells.

The proto-oncogene product c-Fos, a component of the transcription factor AP-1, is induced in early B lineage cells. To investigate a role of c-Fos in early B cell development, fetal liver (FL) cells from transgenic mice carrying an IFN-alphabeta (IFN)-inducible c-fos gene (Mx-c-fosD) were cultured on a stromal cell layer with IL-7. Although B lineage cells normally developed in the Mx-c-fosD FL cell culture, the development was perturbed by the addition of IFN at the beginning of culture. When IFN was added in the FL culture after B lineage cells developed, pro-B (B220+,CD43+) cells were selectively dying by apoptosis within 48 h after IFN stimulation. This apoptosis was intrinsically induced in the pro-B cells that overexpressed c-fos when the Mx-c-fosD FL (H-2Kb) cells were cocultured with the normal C3H FL (H-2Kk) cells. The molecular basis of the apoptosis was investigated by examining expression of the genes that regulate apoptosis. The IFN stimulation did not modulate expression of Bcl-2 and Fas in early B lineage cells from the Mx-c-fosD FL culture. However, Rag-2 was down-regulated in these cells within 12 h after IFN stimulation. These results suggest that the c-Fos plays a causal role in deletion of pro-B cells with nonfunctional Ag receptor.

Animals↗
PubMed1996

p53-dependent G1 arrest and p53-independent apoptosis influence the radiobiologic response of glioblastoma.

PURPOSE: Loss of the p53 tumor suppressor gene has been associated with tumor progression, disease relapse, poor response to antineoplastic therapy, and poor prognosis in many malignancies. We have investigated the contribution of p53-mediated radiation-induced apoptosis and G1 arrest to the well described radiation resistance of glioblastoma multiforme (GM) cells. METHODS AND MATERIALS: Radiation survival in vitro was quantitated using linear quadratic and repair-saturation mathematical models. Isogenic derivatives of glioblastoma cells differing only in their p53 status were generated using a retroviral vector expressing a dominant negative mutant of p53. Radiation-induced apoptosis was assayed by Fluorescence-activated cell sorter (FACS) analysis, terminal deoxynucleotide transferase labeling technique, and chromatin morphology. Cells were synchronized in early G1 phase and mitotic and labeling indices were measured. RESULTS: Radiation-induced apoptosis of GM cells was independent of functional wild-type p53 (wt p53). Decreased susceptibility to radiation-induced apoptosis was associated with lower alpha values characterizing the shoulder of the clonogenic radiation survival curve. Using isogenic GM cells differing only in their p53 activity, we found that a p53-mediated function, radiation-induced G1 arrest, could also influence the value of alpha and clonogenic radiation resistance. Inactivation of wt p53 function by a dominant negative mutant of p53 resulted in a significantly diminished alpha value with no alteration in cellular susceptibility to radiation-induced apoptosis. The clonal derivative U87-LUX.8 expressing a functional wt p53 had an alpha (Gy-1) value of 0.609, whereas the isogenic clonal derivative U87-175.4 lacking wt p53 function had an alpha (Gy-1) value of 0.175. CONCLUSION: We conclude that two distinct cellular responses to radiation, p53-independent apoptosis and p53-dependent G1-arrest, influence radiobiological parameters that characterize the radiation response of glioblastoma cells. Further understanding of the molecular basis of GM radiation resistance will lead to improvement in existing therapeutic modalities and to the development of novel treatment approaches.

Apoptosis↗
PubMed1996

A regulatory role of c-Fos in the development of precursor B lymphocytes mediated by interleukin-7.

The proto-oncogene product c-Fos, a component of the transcription factor AP-1, plays a critical role in the expression of genes required for cellular proliferation and differentiation. The c-Fos is induced in early B lineage cells developed in the interleukin-7-dependent bone marrow (BM) cell culture from normal mice. In order to investigate a role of the c-Fos in early B cell development, we have used BM cells from two different transgenic mice carrying the exogenous c-fos gene controlled by the promoter of the H-2Kb gene (H2-c-fos) or the interferon alpha/beta (IFN)-inducible Mx gene (Mx-c-fosD). Development of B lineage cells was retarded in the BM cell culture from H2-c-fos mice. Although B lineage cells normally developed in the BM cell culture from Mx-c-fosD mice without IFN stimulation, the development was completely blocked in the Mx-c-fosD culture when transgenic c-fos was induced in BM cells by IFN stimulation. Furthermore, the IL-7-dependent proliferation of B lineage cells in Mx-c-fosD BM cells was also suppressed by the induction of c-Fos. These results suggest that the c-Fos plays a role as a negative regulator in the early B cell development.

Animals↗