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Biomedical subjects

R Z Wang

Publications and source records attributed to R Z Wang.

At least 19 recordsLinked to original sources
PubMed2001

[Clonning and identification of the gene encoding specific IgE antibody-related antigen of Schistosoma japonicum].

OBJECTIVE: To obtain the gene encoding specific IgE-related antigen of Schistosoma japonicum from the cDNA library of adult Schistosoma japonicum. METHODS: The pooled sera from 15 individuals with high levels of specific IgE antibody against SWAP were absorbed with Protein-G and used for screening of IgE-related antigen from the adult worm cDNA library of Schistosoma japonicum. The inserted cDNA was amplified by PCR and sequenced. According to the first reading frame of the sequence, a pair of new probes, in which EcoR I and Not I sites were incorporated respectively, were designed and used to amplify the target gene. Then, the gene was cloned into vector pGEM-T and subcloned into expression vector pGEX-6p-1. The fusion protein was expressed, analysed by SDS-PAGE and identified by Western blotting with the specific IgE antibody, respectively. RESULTS: The inserted cDNA fragment from the positive clone was about 1,200 bp, with the ORF of 507 bp which encoded 169 amino acids. The deduced molecular weight of the recombinant protein was 19.3 kDa. The homology between the target gene (Sj43B) and other known DNA sequences was less than 40%. The fusion protein expressed by the recombinant vector pGEX-6p-1/Sj43B could be recognized by schistosome specific IgE antibody. CONCLUSION: Sj43B may encode the specific IgE-related antigen of Schistosoma japonicum. The successful construction of recombinant plasmid pGEX-6p-1/Sj43B lay the groundwork for further studies on immunological characteristics and protection immunity of the recombinant protein.

Animals↗
PubMed2001

[Magnetic resonance imaging of pituitary hyperplasia in a child with growth arrest and primary hypothyroidism].

We report a case of pituitary hyperplasia in a child presented with significant growth arrest and laboratory evidence of hypothyroidism. Magnetic resonance imaging (MRI) revealed symmetrical pituitary enlargement seemed to be macroadenoma. After thyroid hormone replacement therapy, the child's height increased and pituitary enlargement regressed. Awareness of MRI appearance of pituitary hyperplasia in children with laboratory evidence of hypothyoidism might avoid misdiagnosis for pituitary tumor, which may also manifest as growth disorder, obviating unnecessary surgery.

Child↗
PubMed2000

[Gene cloning and characterization of mitochondria-related protein of Schistosoma japonicum].

OBJECTIVE: To subclone and characterize a cDNA clone coding for Schistosoma japonicum (S.j.) mitochondria-related protein. METHODS: The open reading frame of the fragment(Sj338/24) obtained from an adult worm cDNA library of S.j. was analysed, at the upstream and downstream of the open reading frame(ORF) the primers A and B were designed, respectively, and the cDNA fragment was used as PCR template. The Sj338 gene fragment obtained was amplified by PCR method and then subcloned into pGEM-T vector for sequencing. The gene sequence was analyzed and the target fragment was restrictedly digested and subcloned into expression vector pGEX-6P-1. The expressed recombinant protein was purified and characterized. RESULTS: The cloned Sj338 gene was demonstrated to be 487 bp long containing one 459 bp ORF, encoding a protein with a molecular weight of 17 kDa. The nucleotide sequence of the cloned gene Sj338 had higher homology with those genes coding for mitochondrial outer membrane protein of Homo sapiens and Rattus norvegicus. The recombinant construct of pGEX-6P-1/Sj338 could be expressed efficiently and the antigenicity of its product rSj338 has been demonstrated by Western blotting. CONCLUSION: Sj338 may be the gene coding for S.j. mitochondria-related protein and the recombinant protein may be used as a new vaccine candidate.

Amino Acid Sequence↗
PubMed1998

Strain-structure relations in human teeth using Moiré fringes.

Teeth are subjected to stress during normal function. The manner in which the resulting strain is distributed within the tooth is related to its structure. The Moiré fringe technique was used to map the in-plane strain distribution in slices from human tooth crowns under compression. The strain inside enamel is much less than in dentin, and there is a roughly 200 microm thick zone in dentin beneath the dentin enamel junction which undergoes larger strain than the central coronal dentin. This zone is softer and less mineralized than the bulk of the dentin. The strain distribution in this zone along the dentin-enamel junction shows localized maxima on both the lingual and the labial sides. This study is consistent with the hypothesis that within the dentin there are structural adaptations for transferring and minimizing stress.

Bicuspid↗
PubMed1997

Design strategies of sea urchin teeth: structure, composition and micromechanical relations to function.

The teeth of sea urchins comprise a variety of different structural entities, all of which are composed of magnesium-bearing calcite together with a small amount of organic material. The teeth are worn down continuously, but in such a way that they remain sharp and functional. Here we describe aspects of the structural, compositional and micromechanical properties of the teeth of Paracentrotus lividus using scanning electron microscopy, infrared spectrometry, atomic absorption. X-ray diffraction and microindentation. The S-shaped single crystalline calcitic fibres are one of the main structural elements of the tooth. They extend from the stone part to the keel. The diameter of the fibres increases gradually from less than 1 micron at the stone tip to about 20 microns at the keel end, while their MgCO3 contents decrease from about 13 mol% to about 4.5 mol%. Each fibre is coated by a thin organic sheath and surrounded by polycrystalline calcitic discs containing as much as 35 mol% MgCO3. This structure constitutes a unique kind of gradient fibre-reinforced ceramic matrix composite, whose microhardness and toughness decrease gradually from the stone part to the keel. Primary plates are also important structural elements of the tooth. Each primary plate has a very unusual sandwich-like structure with a calcitic envelope surrounding a thin apparently amorphous CaCO3 layer. This central layer, together with the primary plate/disc interface, improves the toughness of this zone by stopping and blunting cracks. The self-sharpening function of the teeth is believed to result from the combination of the geometrical shape of the main structural elements and their spatial arrangement, the interfacial strength between structural elements, and the hardness gradient extending from the working stone part to the surrounding zones. The sea urchin tooth structure possesses an array of interesting functional design features, some of which may possibly be applicable to materials science.

Animals↗
PubMed1997

Advanced glycation end products in human penis: elevation in diabetic tissue, site of deposition, and possible effect through iNOS or eNOS.

OBJECTIVES: We hypothesized that advanced glycation end product (AGE) formation contributes to erectile dysfunction (ED) by quenching nitric oxide. Our first goal was to identify the specific AGE pentosidine in the diabetic human penis. Because AGE-mediated effects may involve inducible nitric oxide synthase (iNOS), we performed immunohistochemical and Western blot analysis of diabetic and nondiabetic human penile tissue for iNOS. Finally, because AGEs may act intracellularly to affect proteins, we set out to identify endothelial NOS (eNOS) in the human penis as an initial step in examining a possible intracellular interaction between eNOS and AGEs. METHODS: We performed high-performance liquid chromatographic analysis of diabetic human penile corpus cavernosum and serum for pentosidine and performed immunohistochemical, electron microscopic (EM), and Western blot analysis of the diabetic and nondiabetic penile corpus cavernosum and tunica for pyrraline, iNOS, and eNOS (and neural NOS [nNOS] for comparative purposes) via standard methods. RESULTS: We found a significant elevation of pentosidine in the penile tissue but not the serum of diabetic patients (average age 55.6 +/- 2.3 years) compared with that of nondiabetic patients (average age 61.8 +/- 3.6 years). Pentosidine was 117.06 +/- 9.19 pmol/mg collagen in the diabetic tunica versus 77.58 +/- 5.5 pmol/mg collagen in the nondiabetic tunica (P < 0.01) and 74.58 +/- 8.49 pmol/mg collagen in the diabetic corpus cavernosum versus 46.59 +/- 2.53 pmol/mg collagen in the nondiabetic corpus cavernosum (P < 0.01), suggesting a tissue-specific effect of the AGEs. We localized the site of deposition of the specific AGE pyrraline to the human penile tunica and the penile corpus cavernosum collagen. Immunohistochemical and EM analysis localized eNOS and iNOS to the cavernosal endothelium and smooth muscle. Western blot analysis in 6 patients revealed the following: iNOS, but no eNOS, in penile tissue from 1 insulin-dependent diabetic man; eNOS only in 1 man after radical prostatectomy; both eNOS and iNOS in 2 men with Peyronie's disease, as well as in 2 other men with impotence and hypertension. Finally, the specific iNOS inhibitor PNU-19451A significantly augmented relaxation of precontracted human cavernosal tissue, from 64.7% +/- 5.58 to 80.03% +/- 4.55 at 10 microM acetylcholine and 65.06% +/- 2.84 to 86.16% +/- 3.96 at 0.1 mM acetylcholine (n = 4, P < 0.002 and P < 0.02, respectively). CONCLUSIONS: AGEs are elevated in diabetic human penile tissue, but not in serum, and are localized to the collagen of the penile tunica and corpus cavernosum. We identified eNOS and iNOS in the human penile cavernosal smooth muscle and endothelium. The augmentation of cavernosal relaxation with a specific iNOS inhibitor, combined with the identification of iNOS protein, but not eNOS, in a patient with severe diabetes and ED, allows for speculation of a pathophysiologic mechanism for AGE-mediated ED via upregulation of iNOS and downregulation of eNOS. These data provide further insight into the mechanisms of advanced glycation end product-mediated ED and provide a foundation for further study.

Adult↗
PubMed1996

[Variability of the parameters of oscillatory potentials of the human electroretinogram].

Oscillatory potentials (OP) of the electroretinogram (ERG) of 20 subjects providing 30 normal eyes were recorded by means of Ganzfeld stimulation at 11 stimulus intensities. It was found that intensity-implicit time functions of the OP components are exponential, while the intensity-response curves are highly variable. The amplitudes of the four wavelets showed relatively large coefficients of variation and intersubject variation, while those of the implicit time are small. Thus it appears that measurement of oscillatory potential implicit time rather than amplitude may provide a more reliable index to access certain retinal condition.

Adult↗
PubMed1994

[Daunomycin-human albumin microspheres (dau-ha-ms)--preparation, characterization and use in experimental cancer therapy].

For the purpose of enhancing the therapeutic index and reducing the toxic effect of chemotherapeutic drugs, Dau-HA-Ms was prepared, mostly as monodispersed microspheres with a mean diameter of 52 +/- 16 microns, ranging from 29 to 194 microns, being suitable for the use of transarterial embolization (TAE) therapy. Dau released effectively in physiological saline solution from microspheres without burst release. The spectrophotometric characteristics and cytotoxic effect in vitro of the released Dau remained unchanged, retaining the original physicochemical and biological properties. It was demonstrated that 30% of mice bearing S-180 sarcoma ascites treated with intraperitoneal injection of Dau-HA-MS survived longer than 6 months, while all tumor bearing control mice and Dau treated tumor bearing mice died within 21 and 14 days, respectively. The results show that Dau-HA-MS is therapeutically more effective and less toxic than Dau, Dau-HA-MS can possibly be used in TAE therapy for human liver cancer.

Animals↗
PubMed1991

[Detection of Plasmodium falciparum infection in humans by (Dig)-DNA probe].

In this study, we used Digoxigenin, (Dig)-11-dUTP, in the Genius kit purchased from Boehringer Mannheim to label the Plasmodium falciparum (P.f.) DNA fragment by random primed labelling method. The P. falciparum DNA fragment was isolated from the recombinant clone pPF14 by enzyme digestion and agarose electrophoresis. This probe is designated pPF14-F-Dig. Purified P.f. DNA and blood samples from malaria patients in Hainan Province of China were detected by the probe in dot-blot hybridization. Thirty-eight patients with falciparum malaria, three with falciparum malaria and vivax malaria and four with vivax malaria were detected with the pPF14-F-Dig probe. The results showed that the pPF14-F-Dig probe could detect at least 40 pg of P.f. DNA and a parasitemia of 0.005 percent. Out of 38 detected P.f. patients' blood samples, 33 hybridized positively with this probe. The positivity rate was 86.8%. Twenty-one normal blood samples all showed negative. In addition, 2 of 3 samples with P.f. and P.v. were positive. Three of 4 samples with P.v. were negative and one was doubtful. The preliminary result of this study indicates that the pPF14-F-Dig probe could detect the patients of falciparum malaria with good sensitivity and specificity, and that this probe can be used to detect the patients with P. falciparum in Hainan Province.

Animals↗
PubMed1989

Observation on the effect of sodium nitroprusside and dopamine on acute myocardial infarction during hospitalization.

With improvements in cardiac monitoring systems and the effective treatment of arrhythmias, the case-fatality rate of acute myocardial infarction (AMI) has been declining gradually since 1972. But since 1977, despite the great efforts of medical workers in many countries, the lowest case-fatality rate of AMI has still been about 10%. Over many years, our institute has carried out research aimed at improving the treatment of AMI. However, in our institute the case-fatality rate has fluctuated between 15 and 20% in recent years. From March 1986 to January 1987 we adopted a sodium nitroprusside and dopamine intravenous drip in the treatment of 92 cases of AMI and achieved a hospitalization period AMI case-fatality rate of less than 5% (2 patients died). The treatment methods and relevant materials are reported here.

Adult↗
PubMed1987

[Clinicopathological study of combined preoperative radiotherapy with intracavitary hyperthermia in rectal cancer].

118 specimens of rectal cancer were studied pathologically. 40 cases were treated by both preoperative radiotherapy and intracavitary hyperthermia (group 1), 38 treated by preoperative radiotherapy alone (group 2) and 40 by operation alone (group 3). The tumor disappearance rates by gross observation were 57.5% and 5.3% in groups 1 and 2 (P less than 0.001). The moderate to severe damage of cancer cells (X2-X4) was observed in 90% of cases in group 1 and 31.6% in group 2 (P less than 0.05). In the former, the cancer cell disappearance was observed in 8 cases, while in the latter, only 1 case. The cell degenerations by 30 Gy plus hyperthermia were similar to those by 40 Gy plus hyperthermia, but both were more marked than by 30 Gy alone or 40 Gy alone (P less than 0.05). The lymphocyte, plasma cell infiltration and hyperplasia of fibrous tissue around the tumor in group 1 were more marked than those in groups 2 and 3 (P less than 0.05). The thrombosis around the tumor was more in group 1 than in group 2 (P less than 0.01). Every histological type of the tumor was sensitive to radiotherapy combined with hyperthermia. The lymph node metastatic rates were 35% in group 1 and 31.6% in group 2, both being lower than that in group 3 (52.5%). Immune function of the lymph nodes and the damage of the normal tissues around the tumor are observed. It has been clinically confirmed that neither resection rate is influenced nor postoperative complications are increased by preoperative radiotherapy combined with hyperthermia.

Adenocarcinoma, Mucinous↗
PubMed1987

[Chemoprevention of cancer of the uterine cervix--preliminary study on the intervention of the cervical precancerous lesion by retinamide RII].

Twenty seven women with mild, moderate or severe cervical dysplasia proven by pathology were treated by retinamide RII suppository. Retinamide RII suppository, 10 mg QD, was given intravaginally for six months (three months as a course). Clinical examination, Papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results indicated that after the second course, 26 out of 27 patients responded; of them, precancerous lesions disappeared in 24 and even normal squamous epithelium was observed in 3. The overall response rate was 96.29% and the marked response rate was 88.89%. The general side effects were mild. There was little cervical and vaginal irritation which was well tolerated. The results of this clinical trial make available a practical base for chemoprevention of cervical cancer.

Antineoplastic Agents↗