On-column refractive-index detection based on retroreflected beam interference for capillary electrophoresis

A novel refractive-index detection scheme used for capillary electrophoresis detection, based on the interference of two retroreflected beams from the outer surface of a capillary tube illuminated by a focused laser beam, is described. A theoretical description and experimental measurement of the intensity profile of the interference fringe pattern in the detection plane are presented. The factors that limit the sensitivity of the proposed refractive-index detection scheme are discussed and compared with the transmitted beam interference and backscatter-based refractive-index detection configurations. The proposed refractive-index detector was used successfully for detection of capillary electrophoresis separations of saccharose, maltose, and lactose with a capillary tube of 50-mum inner diameter and a simple experimental setup.

[Microvasculature of the dog's periodontal ligament and its immediate response to orthodontic forces]

The purpose of this study was to examine the microvascular architecture of dog's periodontal ligament (PDL) and its immediate response to horizontal orthodontic force. A force of 200 g was applied mesially to the mandibular premolar of a dog for 2 hours, the distal side served as the contrast side. Formalin ink was perfused into the carotid arteries bilaterally through the cannulas. After perfusion the mandible was decalcified, celloidin embedded, serially sectioned and stained with eosin. The sections were then observed by light microscope and analyzed by image analyzer. Vascular corrosion casts were prepared by the similar way with the formalin ink perfusion and examined by scanning electron microscope. The results showed: there were extensive interconnections among the PDL, dental pulp, gingiva, alveolus and the neighbour tooth PDL, which would benefit the maintenance of health and functions of the dental pulp and the periodontal tissues. Arterioles and venulae could be confirmed by the presence of characteristic differences of nuclear impressions in endothelial cell under the scanning electron microscope. The quantitative analysis showed that the tensioned PDL sites in the experimental group had a higher microvascular volume density than the corresponding sites in the contrast group, while the pressed PDL sites in the experimental group had a lower microvascular volume density than the corresponding sites in the contrast group. This should result from the hydraulic mechanism in the PDL.

The human homolog of rat Jagged1 expressed by marrow stroma inhibits differentiation of 32D cells through interaction with Notch1

A cDNA clone encoding the human homolog of rat Jagged1 was isolated from normal human marrow. Analyses of human stromal cell lines indicate that this gene, designated hJagged1, is expressed by marrow stromal cells typified by the cell line HS-27a, which supports the long-term maintenance of hematopoietic progenitor cells. G-CSF-induced differentiation of 32D cells expressing Notch1 was inhibited by coculturing with HS-27a. A peptide corresponding to the Delta/Serrate/LAG-2 domain of hJagged1 and supernatants from COS cells expressing a soluble form of the extracellular portion of hJagged1 were able to mimic this effect. These observations suggest that hJagged1 may function as a ligand for Notch1 and play a role in mediating cell fate decisions during hematopoiesis.

[The influence of electroacupuncture on the mast cells in the acupoints of the stomach meridian]

Giving electroacupuncture at unilateral "Biguan" and "Zusanli" points, we observed the rat subcutaneous mast cells of "Tianshu", "Biguan", "Futu", "Zusanli" and "Xiajuxu" acupoints in bilateral Stamach Meridian. It was found that the numbers of mast cells in all the acupoints studied were higher than that in the non acupoint area. The numbers of mast cell in acupoints were increased under electroacupuncture, while that in non acupoint area was not changed. The results suggested the mast cells play an important role in the functions of the Meridian.

[Effects of electroacupuncture on the subcutaneous mast cells of zusanli acupoint in rat with unilateral sciatic nerve transection]

Electroacupuncture could induce the convergence and degranulation of subcutaneous mast cells in acupoints. After unilateral transection of sciatic nerve, we studied the numbers of subcutaneous mast cells and its degranulation in bilateral Zusanli and Xiajuxu acupoints with electroacupuncture in Zusanli. We found that sciatic nerve transection could reduce the total numbers of mast cells and the degranulation numbers of mast cells in Zusanli. The results suggested peripheral nerves play an important role in the convergence and degranulation of mast cells in acupoints by electroacupuncture induction.

[Transduction of antisense RNA of MHC-II gene into CD3+ cord blood stem/progenitor cells inhibits the expression of HLA-DR antigen]

OBJECTIVE

To explore whether the antisense RNA of HLA-DR gene could modulate the expression of the gene and reduce the immunogenicity of cord blood (CB) cells.

METHODS

A retroviral vector encoding antisense RNA of HLA-DR gene was constructed and transducted into packaging cell line PA317 by lipofectin. CD34+ hematopoietic stem cells/progenitors were sorted and enriched by MACS.

RESULTS

A high titer (1 x 1095) cfu/ml) helper-free,virus producing cell PA317 was obtained. The vector was identified by blot hybridization and mapping of restriction points. The CD3+ CB cells were infected by the supernatant of the viral cultures. The G418-resistant clone was demonstrated to express the antisense RNA of HLA-DR gene by RT-PCR technique. The expression rate of HLA-DR antigen on CB cells was 28%, which was apparently lower than that of the control (45%) with an inhibition rate of 38.25%.

CONCLUSION

The introduction of antisense RNA of HLA-DR gene into CB hematopoietic stem cells can successfully decrease the expression of HLA-DR antigen. These studies provide evidences for the prevention and treatment of GVHR in clinical CB transplantation.

[Long-term effects of stapes elevation]

To assess the clinical value of stapes elevation, 38 cases had been followed-up for 1-12 years (average 6.7 years). The results revealed that hearing improvement rate (over 10 dB) was 94.7% in short term and 86.8% in long term follow-up. The long term regression rate was similar to that in stapedectomy, and no severe sensorineural hearing loss occurred. In addition, the vestibular reaction was slight, especially in reoperated cases. The stapes elevation was easy to perform as compared with stapedectomy. Therefore, this technique may be the first choice for stapes surgery.

Preparation of (R)-N-methylsalsolinol via reversed-phase high-performance liquid chromatography using beta-cyclodextrin as a mobile-phase additive

A new preparation method was devised using beta-cyclodextrin as a mobile-phase additive in a reversed-phase high-performance liquid chromatography system. Preparative separation of the biologically active (R)-enantiomer was achieved from racemic N-methylsalsolinol. Beta-cyclodextrin was removed completely in good yield by acid extraction and solid-phase extraction. By a slight modification, this method will be applicable to the isolation of various types of biologically important enantiomers.

On-column indirect photothermal interference detection for capillary zone electrophoresis

An indirect photothermal interference detection method, which is based on the diffraction of a probe laser beam by a capillary tube, for detecting metal cations separated by capillary zone electrophoresis (CZE) is described. In this capillary photothermal interference detector, a 2 mW He-Ne probe laser is employed to provide the probe beam and an 18 mW He-Ne pump laser is used to supply the pump beam. Factors that contribute to the noise and signal in indirect photothermal interference detection in CZE, such as the noise from the scattered light caused by both the probe beam and the pump laser beam, and effects of the concentration of ethanol and NaCl on the separation efficiency, were studied. The effect of scattered light can be reduced effectively with the configuration constraints investigated for photothermal capillary absorption measurements. With Methylene Blue added to carrier electrolyte as an absorber, three typical metal cations (KI, CuII and AlIII) were separated using this system. For CuII, a 2.1 x 10(-7) mol l-1 concentration detection limit (S/N = 2) without preconcentration and a 1.02 x 10(-17) mol detection limit as absolute amount were measured, considering the optical sampling volume estimated to be 50 pl, and 1.99 x 10(6) theoretical plates were observed on the laboratory-made CE system. It was demonstrated that indirect photothermal interference detection is suitable for small capillaries and a large ionic strength range for CE analysis.

Electrochemical behavior of [ReI(DMPE)3]+, where DMPE = 1,2-bis(dimethylphosphino)ethane, at perfluorosulfonated ionomer-modified electrodes

The perfluorosulfonated ionomer Nafion shows potential utility as a polymer film to enhance the electrochemical detection of [ReI(DMPE)3]+, where DMPE = 1,2-bis-(dimethylphosphino)ethane. [ReI(DMPE)3]+, a nonradioactive radiopharmaceutical analog for heart imaging, partitions strongly into Nafion films on glassy carbon. Well-defined, chemically reversible cyclic voltammograms are obtained for the [ReI(DMPE)3]+/[ReII(DMPE)3]2+ couple with Eo' shifted positively by 60 mV relative to its value on bare glassy carbon. [ReI(DMPE)3]+ partitions into Nafion more strongly than the oxidized form, [ReII-(DMPE)3]2+. The detection limit for [ReI(DMPE)3]+ by cyclic voltammetry was improved by 2-3 orders of magnitude by the Nafion film. Differential pulse voltammetry for oxidation of [ReI(DMPE)3]+ at the Nafion-modified electrode has a detection limit of 2.5 x 10(-9) M compared to 1.0 x 10(-7) M at the bare electrode. A preconcentration factor of 1 x 10(6) for partitioning of [ReI(DMPE)3]+ from 0.05 M NaCl into Nafion on a glassy carbon electrode was measured.

[Effects of glycated protein on the expression of plasminogen activator inhibitor-1 of cultured human mesangial cells]

OBJECTIVE

To investigate whether nonenzymatic glycated end products (AGEs) have effects on the expression and bioactivity of plasminogen activator inhibitor-1 (PAI-1), one of the seripin proteinases, which lead to extracellular matrix (ECM) degradation in cultured human mesangial cells.

METHODS

Human mesangial cells (HMC) were cultured. Cell proliferation, fibronectin production, mRNA expression and bioactivity of PAI-1 were determined after exposure to AGE-BSA for 24 hours and 48 hours in vitro.

RESULTS

HMC stimulated by AGE-BSA exhibited inhibition in HMC proliferation, increase in fibronectin production, and PAI-1 bioactivity. These changes were pronounced with prolongation of experimental time. PAI-1 mRNA expression increased significantly at 24 hr (0.45% +/- 0.06% vs 0.65% +/- 0.08%, P < 0.05), however more marked increase of PAI-1 mRNA expression at 48 hr (0.51 +/- 0.08% vs 0.92 +/- 0.10%, P < 0.01).

CONCLUSIONS

Increase of mRNA expression and bioactivity of PAI-1 induced by AGEs decreased ECM degradation and play an important role in the pathogenesis of ECM accumulation and glomerulosclerosis.

Extremely low awareness of AIDS, sexually transmitted diseases and condoms among Dai ethnic villagers in Yunnan province, China

OBJECTIVE

To assess the awareness of AIDS, other sexually transmitted diseases (STDs), condoms, sources of health information and HIV-related societal risks among Dai villagers in southern Yunnan Province, China.

SUBJECTS AND METHODS

In November-December 1994, a cross-sectional descriptive study, comprising a questionnaire-based survey and focus group discussions, was conducted in three Dai villages in Mengla county; a total of 177 Dai villagers were interviewed in the survey and eight focus group discussions were held. Ethnographic observations provided a composite picture of HIV risks in the area.

RESULTS

Only 18% of respondents had heard of AIDS, and only 25 and 28%, respectively, had heard of STDs or condoms. Furthermore, among these more aware groups, the level of knowledge was low and misconceptions were common. An ability to understand the official language (Mandarin) was the most important predictor of awareness of AIDS, other STDs or condoms. The sources of information in the three Dai villages sampled included TV, videos, radio and magazines, but only TV and videos had a large audience. Even so, these media were mostly in Mandarin and were not used in AIDS education. Travel outside of China was frequent; most villagers (77%) had traveled to Laos and 9% had traveled to Thailand. Societal risks of HIV transmission, such as an increasing incidence of STDs and an active sex industry, were observed in this area.

CONCLUSIONS

Dai villagers in southern Yunnan Province had an extremely low awareness and knowledge of AIDS, other STDs and condoms. Given the high mobility of ethnic villagers to neighboring countries in Southeast Asia and the societal risks of HIV transmission in this area, there is an urgent need to provide accessible education about AIDS and other STDs. Suggestions regarding such health education and the implications of HIV policy-making are discussed.

Alagille syndrome is caused by mutations in human Jagged1, which encodes a ligand for Notch1

Alagille syndrome is an autosomal dominant disorder characterized by abnormal development of liver, heart, skeleton, eye, face and, less frequently, kidney. Analyses of many patients with cytogenetic deletions or rearrangements have mapped the gene to chromosome 20p12, although deletions are found in a relatively small proportion of patients (< 7%). We have mapped the human Jagged1 gene (JAG1), encoding a ligand for the developmentally important Notch transmembrane receptor, to the Alagille syndrome critical region within 20p12. The Notch intercellular signalling pathway has been shown to mediate cell fate decisions during development in invertebrates and vertebrates. We demonstrate four distinct coding mutations in JAG1 from four Alagille syndrome families, providing evidence that it is the causal gene for Alagille syndrome. All four mutations lie within conserved regions of the gene and cause translational frameshifts, resulting in gross alterations of the protein product Patients with cytogenetically detectable deletions including JAG1 have Alagille syndrome, supporting the hypothesis that haploinsufficiency for this gene is one of the mechanisms causing the Alagille syndrome phenotype.

[Construction of human genomic YAC clones with "terminal modification"]

A human YAC genomic pool with more than 4,000 clones was constructed by means of "terminal modification" of YAC vector and genomic inserts, as well as optimization of relevant experimental parameters. The transformation rate is approximately 400-500 transformants per microgram DNA. Preliminary characterization of randomly sampled clones demonstrates that YAC-specific inserts, in the average size of 450 kb and ranging 150-750 kb, were detected from 80% of the clones. The vector ligation experiment indicates the efficient reduction of "coligation" by terminal modification.

[Expression of Epstein-Barr virus latent membrane protein (EBV-LMP) in human laryngeal carcinoma]

In order to investigate the expression of Epstein-Barr virus in human laryngeal carcinoma, immunohistochemical study for Epstein-Barr virus latent membrane protein (EBV LMP) was performed on 90 laryngeal specimens taken from laryngeal carcinoma patients. The results showed that LMP was localized on the cell membrane and in cytoplasm. LMP was detected in 41 of 90 (45.5%) laryngeal squamous cell carcinoma, among them the positive rates of poorly differentiated, middle differentiated and well differentiated squamous carcinoma were 44% (12/27), 52% (25/47) and 26.6% (4/15) respectively. This study indicated that EB virus was not only presented in poorly differentiated carcinoma, it was also presented in well differentiated carcinoma. The development of laryngeal squamous carcinoma is related to the infection of EB virus.

Localization, quantitation, and in situ detection of specific peptide-MHC class I complexes using a monoclonal antibody

CD8+ T lymphocytes recognize antigens as short peptides bound to MHC class I molecules. Available methods cannot determine the number and distribution of these ligands on individual cells or detect antigen-presenting cells in tissues. Here we describe a method for eliciting and identifying monoclonal antibodies specific for a particular peptide-MHC class I combination. One such antibody can identify antigen complexes with a limit of detection approaching that of T cells. We used this antibody to determine the number of peptide-class I complexes generated upon viral infection, to identify antigen-presenting cells in cell mixtures, to determine the site of peptide-MHC class I interaction inside cells, and to visualize cells bearing specific peptide-MHC class I complexes after in vivo infection. Similar antibodies may prove useful for diagnostic or therapeutic purposes in cancer, infectious diseases, and autoimmune disorders.

[Immunobiological significance of S-100 protein positive dendritic cells (S-100+DC) in patients with oral squamous cell carcinoma]

The purpose of this study is to investigate the role and clinical significance of S-100+DC in oral squamous cell carcinoma. Distribution of S-100+DC in the tumor tissues and regional lymph nodes (LN) of 60 patients with oral squamous cell carcinoma was detected by immunohistochemistry (ABC). The results showed that the S-100+DC density in tumor tissues was correlated with the tumor histologic grade (P < 0.05). The density of S-100+DC was significantly higher in regional LN without tumor than those with metastases (P < 0.05). However, there was no difference of S-100+DC in tumor tissues between patients with and without regional LN metastases. The distribution of S-100+DC in tumor tissues and regional LN could be considered as a reference indicator of tumor histologic grade and clinical prognosis of patients.

A wavelet-based multiresolution regularized least squares reconstruction approach for optical tomography

In this paper, we present a wavelet-based multigrid approach to solve the perturbation equation encountered in optical tomography. With this scheme, the unknown image, the data, as well as the weight matrix are all represented by wavelet expansions, thus yielding a multiresolution representation of the original perturbation equation in the wavelet domain. This transformed equation is then solved using a multigrid scheme, by which an increasing portion of wavelet coefficients of the unknown image are solved in successive approximations. One can also quickly identify regions of interest (ROI's) from a coarse level reconstruction and restrict the reconstruction in the following fine resolutions to those regions. At each resolution level a regularized least squares solution is obtained using the conjugate gradient descent method. This approach has been applied to continuous wave data calculated based on the diffusion approximation of several two-dimensional (2-D) test media. Compared to a previously reported one grid algorithm, the multigrid method requires substantially shorter computation time under the same reconstruction quality criterion.

Inhomogeneous distribution of brightness in the split-element filter

The inhomogeneous distribution of brightness in a split-element filter is discussed. This inhomogeneity is caused by the off-axis effect of the birefringent crystal and can seriously affect astronomical observations in the case of a large field of view. For example, the maximal brightness fluctuation is ~9.44% in a full-disk solar telescope whose maximal incident angle is 70 arcmin. We also discuss ways to avoid this disadvantage.

[A three-month follow-up study of excimer laser photorefractive keratectomy for myopia]

In order to evaluate the efficacy of photorefractive keratectomy (PRK) in the treatment of myopia, we summed up and analysed the 3-month follow-up data on 145 cases treated in our hospital. Prior to PRK, refractive dioptal was -1.5 to -11.5; visual acuity was less than 0.1 in 137 cases (94%) and less than 0.5 in 8 cases(6%). One month after operation, the mean refractive dioptal was +0.98 +/- 0.88; visual acuity increased to > or = 1.0 in 95 cases (66%) and to > or = 0.5 in 142 cases(98%). Three months after operation, the mean refractive dioptal was -0.13 +/- 1.09; visual acuity increased to > or = 1.0 in 104 cases(72%) and to > or = 0.5 in 135 cases(93%). There was no severe complication noted in all cases. The results demonstrate that PRK is and effective, safe and predictable treatment for myopia.

The role of subcellular localization in initiation of apoptosis by photodynamic therapy

Rapid initiation of apoptosis can be induced by photodynamic therapy, depending on the cell line and sensitizer employed. In this study, we evaluated the photodynamic responses to two structurally related photosensitizing agents, using the P388 murine leukemia cell line in culture. Photodamage mediated by tin etiopurpurin involved lysosomes and mitochondria and yielded a rapid apoptotic response; apoptotic nuclei were observed within 60 min after PDT. A drug analog, tin octaethylpurpurin amidine, targeted lysosomes, mitochondria and cell membranes; apoptotic nuclei were not observed until 24 h after PDT. These results, together with other recent reports, are consistent with the hypothesis that membrane photodamage can delay or prevent an apoptotic response to PDT.

Assay for the (R)- and (S)-enantiomers of salsolinols in biological samples and foods with ion-pair high-performance liquid chromatography using beta-cyclodextrin as a chiral mobile phase additive

A chromatographic procedure was devised for the quantitative determination of the enantiomers of salsolinol and N-methylsalsolinol, which are biologically important alkaloids. The enantiomers of salsolinol and N-methylsalsolinol were completely separated using beta-cyclodextrin in a reversed-phase ion-pair system. The HPLC method was sensitive enough to detect the isoquinolines at a concentration less than 0.1 pmol per injection. The presence of (R)- and (S)-salsolinol was confirmed in fermented foods and beverages, while N-methylsalsolinol was not detected. On the other hand, the (R)-enantiomers of both salsolinol and N-methylsalsolinol were found to predominate in the human brain.

MHC affinity, peptide liberation, T cell repertoire, and immunodominance all contribute to the paucity of MHC class I-restricted peptides recognized by antiviral CTL

MHC class I-restricted T cell responses to viral proteins focus on a limited set of peptides. To better understand this phenomenon, we examined all of the 26 nonameric peptides encoded by the influenza virus A/Puerto Rico/8/34 (PR8) conforming to the canonical Kd binding motif. Ten peptides bound strongly to Kd as assessed by a cell surface stabilization assay. Five of these 10 induced in vitro secondary CD8+ T cell responses from splenocytes derived from PR8-immunized mice. The strongest responses were induced by the two previously defined antigenic peptides, which ranked only second and fifth in relative binding affinity. To examine the limiting factors in the immunogenicity of Kd-binding peptides, we produced recombinant vaccinia viruses (rVVs) expressing cytosolic or endoplasmic reticulum (ER)-targeted peptides. rVVs expressing ER-targeted versions of the 7 peptides with the highest relative affinities for Kd rescued Kd cell surface expression in T2 cells, while those expressing the 3 lowest affinity peptides did not. The immunogenicity of several, but not all, of the highest affinity peptides was greatly enhanced when expressed as VV-encoded cytosolic or ER-targeted peptides as compared with full length proteins. We conclude that limitations in the immunogenicity of class I binding peptides reflects, in order of decreasing importance, peptide liberation by cellular proteases, T cell repertoire, and TAP-mediated peptide transport. We also observed an additional important contributing factor: suppression of T cell responses to nondominant peptides by an immunodominant peptide located in the same protein.

MHC affinity, peptide liberation, T cell repertoire, and immunodominance all contribute to the paucity of MHC class I-restricted peptides recognized by antiviral CTL

MHC class I-restricted T cell responses to viral proteins focus on a limited set of peptides. To better understand this phenomenon, we examined all of the 26 nonameric peptides encoded by the influenza virus A/Puerto Rico/8/34 (PR8) conforming to the canonical Kd binding motif. Ten peptides bound strongly to Kd as assessed by a cell surface stabilization assay. Five of these 10 induced in vitro secondary CD8+ T cell responses from splenocytes derived from PR8-immunized mice. The strongest responses were induced by the two previously defined antigenic peptides, which ranked only second and fifth in relative binding affinity. To examine the limiting factors in the immunogenicity of Kd-binding peptides, we produced recombinant vaccinia viruses (rVVs) expressing cytosolic or endoplasmic reticulum (ER)-targeted peptides. rVVs expressing ER-targeted versions of the 7 peptides with the highest relative affinities for Kd rescued Kd cell surface expression in T2 cells, while those expressing the 3 lowest affinity peptides did not. The immunogenicity of several, but not all, of the highest affinity peptides was greatly enhanced when expressed as VV-encoded cytosolic or ER-targeted peptides as compared with full length proteins. We conclude that limitations in the immunogenicity of class I binding peptides reflects, in order of decreasing importance, peptide liberation by cellular proteases, T cell repertoire, and TAP-mediated peptide transport. We also observed an additional important contributing factor: suppression of T cell responses to nondominant peptides by an immunodominant peptide located in the same protein.