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Biomedical subjects

Y Tao

Publications and source records attributed to Y Tao.

At least 145 records · Page 8Linked to original sources
PubMed1995

[Efficacy of praziquantel combined with albendazole in the treatment of clonorchiasis].

This paper reported on the clinical efficacy of praziquantel-albendazole combination in the treatment of clonorchiasis in Guangxi. Two hundred and two cases were divided into three groups. The first group comprised 66 cases who were treated with praziquantel at 180 mg/kg bwt for three days. The second group consisted of 62 cases who were treated with albendazole at 90 mg/kg bwt for three days. In the third group, 74 cases were treated with 90 mg/kg bwt praziquantel plus 45 mg/kg albendazole for three days. The results showed that the negative conversion rates were 98.5%, 61.3% and 87.8% in groups one, two and three, respectively, one month after treatment. In some cases who continued to be egg positive, the reduction rates in faecal egg counts were 99.7%, 65.0% and 97.3%, respectively. Although the cure rate in group three was not as high as in group one, the side effects were more mild and transient and the cost of treatment could be reduced by 60% as compared with group one. In cases with light and moderate infections, the praziquantel-albendazole combination proved more effective. In addition, the praziquantel-albendazole combination was also highly effective for treating those cases who were infected with Ascaris, Trichuris or hookworm.

Albendazole↗
PubMed1995

Platelet-activating factor induces the expression of metalloproteinases-1 and -9, but not -2 or -3, in the corneal epithelium.

PURPOSE: The inflammatory mediator platelet-activating factor (PAF) induces the expression of interstitial collagenase (metalloproteinase-1) messenger RNA in rabbit corneal epithelium. In this study, the authors investigated the effect of PAF on gene expression and protein activity of other matrix metalloproteinases (MMPs) in the cornea. METHODS: Rabbit corneas were incubated in an organ culture with 100 nM of cPAF (a nonhydrolyzable PAF analog), PAF, or lyso-PAF, an inactive metabolite of PAF. In some experiments, the corneas were preincubated for 1 hour with 10 microM BN50730, a PAF antagonist, before cPAF was added to the medium. Corneal epithelial cells and/or conditioned medium were collected at different times for analysis. Also, in vivo experiments were done by injecting 2 micrograms of cPAF intrastromally into rabbit eyes and collecting the epithelium 8 hours later for study. Northern blot analysis and zymography were performed to determine the mRNA abundance and/or enzyme activity of 92 kd gelatinase (MMP-9), 72 kd gelatinase (MMP-2), and stromelysin (MMP-3). The activity of MMP-1 was tested by collagenase assays. RESULTS: cPAF induced the expression of MMP-9 mRNA, but not MMP-3 mRNA. The message was induced at 4 hours and remained elevated at 48 hours, with a peak at 36 hours. In corneas preincubated with BN50730, MMP-9 mRNA activation by cPAF was inhibited. In vivo injection of cPAF also induced the expression of MMP-9. Furthermore, cPAF increased MMP-9 activity in the epithelial cells and in the conditioned media. The effect was blocked by BM50730. cPAF did not affect MMP-2 activity. Finally, cPAF also increased MMP-1 collagenolytic activity of the corneal epithelium, which was blocked by the PAF antagonist. CONCLUSION: These results suggest a novel mechanism by which PAF activates MMPs. The lipid mediator selectively enhances the expression of MMP-1 and MMP-9 in rabbit corneal epithelium. This activation by PAF may be involved in the remodeling mechanisms of the cornea after injury and, when overexpressed, may lead to the formation of corneal ulcers. Specific PAF antagonists could therapeutically deter corneal ulcer formation and facilitate corneal wound healing.

Animals↗
PubMed1995

[A survey on distribution of red cell blood group systems in naxi and primi ethnic groups].

A survey of distribution of red cell blood group systems, including ABO, MNSs, Rh and P, was carried out on the Naxi and Primi ethnic groups in Yunnan province. The results based on 104 cases in each of the two ethnic groups showed that both Naxi and Primi possessed a high gene frequency r of 0.6082 and 0.6882, respectively, with gene frequency p = q. The gene frequency m of Naxi (0.8509) was found to be very high among the populations studied in China until now, only next to that of Lizu (0.8709). The most common phenotype of Rh system was CcDE- in both Naxi and Primi, with a quite high cDE frequency. No case of Rh negative was observed in the two ethnic groups. The P1 in Naxi approximated to that in Primi. The red cell blood group systems and their genetic distances suggested that the Naxi and Primi was genetically close to ethnic groups of North China, but different from those of South China. This fact suggests that these two ethnics groups originated from the North China.

ABO Blood-Group System↗
PubMed1995

Cloning of a gene encoding the precursor of nisin by PCR.

The structural gene for the precursor of nisin was synthesized by polymerase chain reaction and then cloned in pUC18. The nucleotide sequence of the cloned precursor nisin gene was determined by dideoxy termination method. The sequence data obtained agreed with those of precursor nisin genes isolated by other workers from different Lactococcus lactis strains.

Amino Acid Sequence↗
PubMed1994

A phase I trial of intrahepatic verapamil and doxorubicin. Regional therapy to overcome multidrug resistance.

BACKGROUND: Verapamil can modulate multidrug resistance in vitro, but only at levels that are not tolerable when administered systemically. Regional strategies of drug administration may permit the delivery of high concentrations of a drug to specific areas with lower systemic levels. Colorectal cancers typically express the multidrug resistance phenotype. METHODS: A Phase I trial was performed to determine the maximum tolerable dose (MTD) and dose limiting toxicities of verapamil by hepatic artery infusion, together with doxorubicin, to patients with hepatic metastases of colorectal cancer. Fourteen patients with metastatic colorectal cancer received a 14-hour intrahepatic infusion of verapamil. Six hours after the start of the infusion, a fixed dose of doxorubicin (50 mg/m2) was given, also via the hepatic artery, over a 30-minute period. Patients were followed by cardiac telemetry but were not in an intensive care setting, and no invasive monitoring was used. All patients had received prior intrahepatic chemotherapy. RESULTS: The MTD of intrahepatic verapamil on this schedule in this patient population was 1.2 mg/kg/hour. Hypotension was the dose limiting toxicity. No major objective responses were noted in this heavily pretreated patient population. A dose of 1.0 mg/kg/hour is recommended for Phase II trials. CONCLUSIONS: Based on estimations of normal hepatic artery blood flow, the estimated concentration of verapamil delivered to the hepatic tumors at 1.0 mg/kg/hour is 3.6 micrograms/ml (7.3 microM), which is comparable to concentrations at which an in vitro reversal of MDR is seen. This study demonstrates that the systemic toxicities of an MDR reversal agent can be overcome by regional drug delivery, establishing this approach as an important model system for further study of MDR modulation.

Adenocarcinoma↗
PubMed1994

A phase I trial of immediate postoperative intraperitoneal floxuridine and leucovorin plus systemic 5-fluorouracil and levamisole after resection of high risk colon cancer.

BACKGROUND: The purpose of this study was to evaluate the toxicity of immediate postoperative intraperitoneal (IP) floxuridine (FUdR) and leucovorin (LV) after resection of high risk colon cancer, and to determine the appropriate dose of intravenous fluorouracil (FU) plus levamisole during concurrent intraperitoneal therapy. METHODS: The authors conducted a tertiary referral Comprehensive Cancer Center Phase I Trial in patients with resected colon cancer at high risk for recurrence. After resection of all gross disease, intraperitoneal treatment was administered twice daily for 3 days every 2 weeks for three cycles (Days 1-3, 15-17, 29-31). Intravenous FU daily for 5 days was administered on days 29-33 concurrently with the third cycle of intraperitoneal therapy. Fluorouracil doses during the last cycle of intraperitoneal therapy were escalated; intraperitoneal FUdR and LV doses and weekly intravenous FU doses (starting on Day 58) were fixed. RESULTS: Twenty-six patients with resected high risk colon cancer were treated. Three had Dukes' B2, 16 Dukes' C, and 7 Dukes' D (M1) resected tumors. Intraperitoneal therapy was well tolerated with no increase in operative morbidity and no operative mortality. Two patients had > or = Grade 3+ toxicity during IP therapy alone. There were no treatment related deaths. During concurrent intraperitoneal and intravenous chemotherapy, the maximum tolerated dose of FU was 300 mg/m2/day for 5 days. The recommended dose for Phase II or III trials is 200 mg/m2/day for 5 consecutive days. Pharmacokinetic analysis indicated that using the doses used in this trial, measurable systemic concentrations of FUdR and LV were obtained during IP therapy. This may have contributed to observed toxicity with intravenous FU doses of 300-400 mg/m2. With a median duration of follow-up of 18 months, four patients had recurrence of disease. No peritoneal recurrences have been noted to date. CONCLUSIONS: Immediate postoperative IP FUdR and LV are well tolerated after resection of high risk colon cancer. The recommended dose of intravenous FU beginning on Day 29 (concurrent with the last dose of IP therapy) is 5FU 200 mg/m2 for 5 consecutive days. The remaining year of adjuvant fluorouracil and levamisole can be administered with standard dose attenuation. Although follow-up is short, the lack of recurrent peritoneal metastases is encouraging. Additional trials with this approach are warranted in patients with high risk colorectal cancer.

Adult↗
PubMed1994

PCR-based cloning of the full-length Neurospora eukaryotic initiation factor 5A cDNA: polyhistidine-tagging and overexpression for protein affinity binding.

Eukaryotic initiation factor 5A (eIF-5A) is the only cellular protein known to contain a hypusine residue that is formed by transferring the aminobutyl moiety from spermidine to a specific lysine residue, followed by hydroxylation at the aminobutyl group. A simple PCR-based strategy was developed to obtain a full-length cDNA of Neurospora crassa eIF-5A. The strategy consists of (i) the design of a pair of key primers (21-mer) based on the highly conserved eIF-5A cDNA domains known in other species, (ii) PCR amplification of Neurospora cDNA using the two key primers to obtain the core sequence for the design of core primers, and (iii) combined use of the key primers, core primers and the universal primers, T3 and T7, to amplify the target sequence in a Neurospora cDNA library. The longest cDNA obtained was cloned into pBlueScript phagemid, and sequence analysis indicated that it encodes a polypeptide of 163 amino acid residues with a codon usage preference characteristic of abundant Neurospora genes. The Neurospora polypeptide showed 59% and 67% identity with human and yeast eIF-5A precursor protein respectively. We subcloned the Neurospora eIF-5A cDNA into pQE-30, which introduces six adjacent histidine residues to the N-terminus of the recombinant protein. The resulting plasmid, pQTy21, was overexpressed in Escherichia coli, and the soluble polyhistidine-tagged protein was purified by metal chelation chromatography. We obtained about 60 mg of purified eIF-5A precursor from 1 litre of culture in a single step using a Ni(II)-nitrilotriacetic acid (NTA)-agarose column. The histidine-tagged eIF-5A precursor protein could be recognized by anti-Neurospora crassa 21 kDa protein serum raised against wild-type eIF-5A precursor and could serve as the substrate protein for deoxyhypusine synthase. Using the histidine-tagged recombinant protein and the Ni(II)-NTA-agarose column, we constructed a protein affinity column and demonstrated an affinity binding between eIF-5A precursor and deoxyhypusine synthase in the presence of NAD+. One-step eIF-5A precursor affinity-column chromatography could lead to a 30-fold purification of deoxyhypusine synthase.

Amino Acid Sequence↗
PubMed1994

Nitric oxide regulation of glyceraldehyde-3-phosphate dehydrogenase activity in Dictyostelium discoideum cells and lysates.

The ability of compounds releasing nitric oxide (NO) to regulate glyceraldehyde-3-phosphate dehydrogenase (GraPDH) activity was analysed both in cell homogenates and in intact Dictyostelium discoideum. The time course of GraPDH inactivation in cell lysates by NO-releasing compounds suggests that two processes may be involved, one of which accounts for the majority of the inactivation and shows a close correlation with GraPDH ADP-ribosylation. Maximal ADP-ribosylation under these conditions exhibited a stoichiometry of about 0.4 mol ADP-ribose/mol enzyme tetramer. NO-mediated inhibition of GraPDH activity was attenuated if specific substrates, cofactors, or cysteine were added to cytosol preparations. Under such conditions, ADP-ribosylation of the enzyme was correspondingly reduced or negligible. Intact cells treated with NO-releasing compounds were shown to respond by rapidly decreasing their GraPDH activity. This inhibition was transient and, after a 10-min incubation, enzyme activity returned to the level seen in control cells. The time course of these in vivo changes correlated well with those of the NO-stimulated ADP-ribosylation of GraPDH also seen in intact cells. The basis underlying the NO-stimulated inhibition of GraPDH activity was investigated and found to reflect a decreased Vmax. No changes in either the Km of the enzyme for its substrates or its state of polymerization were observed.

Adenosine Diphosphate Ribose↗
PubMed1994

Deoxyhypusine synthase assay based on the use of polyhistidine-tagged substrate and metal chelate-affinity chromatography.

Hypusine formation on the eukaryotic initiation factor 5A (eIF-5A) precursor is a unique spermidine-dependent post-translational modification that appears to be ubiquitous in eukaryotic cells. In this modification, a specific lysine residue of eIF-5A precursor protein is first converted to deoxyhypusine by an addition of a butylamino group derived from spermidine; the deoxyhypusine residue is then hydroxylated to form hypusine. Deoxyhypusine synthase, an NAD(+)-dependent enzyme, catalyzes the first step of hypusine formation on the eIF-5A precursor. Since deoxyhypusine formation represents one of the most specific polyamine-dependent reactions in eukaryotic cells, the reaction may play an important role in cellular growth regulation. To facilitate the study of the function and significance of deoxyhypusine formation, we have developed a rapid and sensitive assay for deoxyhypusine synthase. The assay relied on the use of hexahistidine-tagged recombinant Neurospora 21-kDa eIF-5A precursor protein as the substrate protein. The radiolabeled polyhistidine-tagged protein, once modified by [3H]spermidine, was separated from free [3H]spermidine by a microscale metal-affinity chromatography in a dot blot filtration apparatus and quantified by liquid scintillation counting. The assay procedure is quick and simple compared to other methods reported in the literature. The sensitivity is limited by the specific activity of [3H]-spermidine in the reaction mixture. The metal-affinity chromatographic assay for deoxyhypusine synthase should facilitate the purification, characterization, and functional studies of this enzyme.

Chromatography, Affinity↗
PubMed1994

The necessary and sufficient conditions of density-dependent evolutionary stable strategy (DDESS) in the two-phenotype model.

In this paper, we discuss the stability conditions of both the density-dependent pure and mixed strategy models of a polymorphic haploid population with only two pure strategies. Our results show that for the definition of density dependent evolutionary stable strategy DDESS and its stability. Cressman's frequency conditions are necessary and sufficient, and Cressman's density condition is not required.

Animals↗
PubMed1994

Guinea pig asthma induced by red soft coral (Dendronephthya nipponica) inhalation.

Spiny lobster fishermen on the Pacific coast of Miyazaki Prefecture in Japan develop bronchial asthma due to occupational sensitization to red soft coral (Dendronephthya nipponica). To assess the role of sensitization in the development of bronchial hyperresponsiveness and the relationship between bronchial responsiveness and bronchial inflammation, we established a guinea pig model of red soft coral induced asthma. Twenty-four guinea pigs were intramuscularly immunized with a priming dose of red soft coral, 5 OD280 (15 mg protein) per 0.5 ml, and 0.5 ml complete Freund's adjuvant on day 1. Booster doses were repeated on day 15. By day 43 all sensitized animals showed high hemagglutination titers against red soft coral conjugated sheep erythrocytes and high IgG1 titers by passive cutaneous anaphylaxis. On day 43, the animals were challenged by inhalation of red soft coral extracts, 20 OD280 for 30 min. The respiratory resistance was monitored by the oscillation method. The respiratory resistance increased immediately upon inhalation in all sensitized animals and returned to baseline within 4 h. The bronchial reactivity to acetylcholine, measured 6 h after red soft coral inhalation in the sensitized animals when the respiratory resistance was returned to baseline, increased significantly (p < 0.05) as compared with the values measured 24 h before inhalation. The acetylcholine response measured 30 h later did not differ from preinhalation levels. There was a significant difference in the number of eosinophils (p < 0.001) in lamina propria and epithelium and of lymphocytes (p < 0.05) in the lamina propria 6 h after inhalation in the sensitized animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1994

Improved survival in stage III melanoma patients with GM2 antibodies: a randomized trial of adjuvant vaccination with GM2 ganglioside.

PURPOSE: To perform a double-blind randomized trial with American Joint Commission on Cancer (AJCC) stage III melanoma patients for the following reasons: (1) to confirm our previous finding that patients with antibodies against the melanoma differentiation antigen GM2 have an improved prognosis, and (2) to demonstrate clinical benefit from GM2 antibody induction. PATIENTS AND METHODS: One hundred twenty-two patients with AJCC stage III melanoma who were free of disease after surgery were randomized: 58 to receive treatment with the GM2/BCG vaccine, and 64 to receive treatment with bacille Calmette-Guèrin (BCG) alone. All patients were pretreated with low-dose cyclophosphamide (Cy). RESULTS: GM2 antibody was detected in 50 of 58 patients treated with GM2/BCG and seven of 64 patients treated with BCG alone. With a minimum follow-up period of 51 months, there was a highly significant increase in the disease-free interval (P = .004) and a 17% increase in overall survival (P = .02) in these 57 antibody-positive patients, confirming our earlier experience. Exclusion of all patients with preexisting GM2 antibodies (one in the GM2/BCG group and five in the BCG group) from statistical analysis resulted in a 23% increase in disease-free interval (P = .02) and a 14% increase in overall survival (P = .15) at 51 months for patients treated with the GM2/BCG vaccine. However, when all patients in the two treatment groups were compared as randomized, these increases were 18% for disease-free interval and 11% for survival in the GM2/BCG treatment group, with neither result showing statistical significance. CONCLUSION: (1) Vaccination with GM2/BCG induced immunoglobulin M (IgM) antibodies in most patients. (2) GM2 antibody production was associated with a prolonged disease-free interval and survival. (3) Comparison of the two arms of this trial as randomized fails to show a statistically significant improvement in disease-free interval or survival for patients treated with GM2/BCG vaccines.

Adolescent↗
PubMed1994

Distribution of red cell blood group systems in Achang and De'ang ethnic groups in China.

A survey on the distribution of red cell group systems, including ABO, MNSs, Rhesus and P, was carried out in the Achang and De'ang ethnic groups in Yunnan Province, South-West China. The Achangs are characterized by the highest frequency of IA in China, while the De'angs show a high frequency of IO and CDe. The distribution of these blood group systems in Achang and De'ang exhibits the same characteristics observed in other ethnic groups of South China.

ABO Blood-Group System↗
PubMed1994

[Clinical application of rhombotrapezious island musculocutaneous flap for skull base and/or craniomaxillary operation with malignant tumor].

Regional pedicled musculocutaneous flaps are the mainstay of the head and neck reconstruction. They provide a rapid, highly reliable and single-staged technique that is applicable in most cases. The rhombotrapezious island musculocutaneous flap is valuable in the base and craniomaxilloface reconstruction. In this study we updated our experience with the rhombotrapezious island musculocutaneous flap (RTIMF) in 6 cases from 1989 to 1993. Dissections were performed on 9 cadavers, 4 preserved and 5 fresh, yielding 18 pairs or dorsal scapular and transverse cervical artery for evaluation. In the five fresh cadavers, the arteries were selectively cannulated and injected with colored latex. 67% with dorsal scapular and transverse cervical artery commonly arose from the thyro-cervical trunk. 33% with the dorsal scapular artery directly arose from the second part of the subclavian artery. In the period of 1989-1993, 6 rhombotrapezious island musculocutaneous flaps with vascularized pedicle were used for immediate repair in the skull base or craniomaxillary cancer operations. There was no complication of the flaps. Donor site complications were relatively minor. The disturbance in shoulder function was well tolerated. We advocated the incorporation of both the greater and lesser rhomboid muscle to form the compound rhombotrapezious flaps to enhance the vascular supply to the overlying skin. The major advantage of the RTIMF are that it provides a long paddle of thin pliant, hairless skin and muscle that can be rotated as far as the craniomaxilloface and scalp in a single stage. It offers the longest arc of rotation and thus the greatest versatility for the skull base or craniomaxillary reconstruction.

Adult↗
PubMed1994

[A case of limited Wegener's granulomatosis with hemophilia A, complicated by empyema, bronchopleural fistula and herpes zoster during therapy].

A 36-year-old man with hemophilia A was admitted to hospital because of otalgia, hearing loss, nasal obstruction, nonproductive cough, and high fever. His laboratory data showed high-grade acute inflammatory reactions. His chest X-ray and CT films showed multiple cavitary masses in the right lower lung field. Bronchoscopy performed at our institution revealed bronchial nodules in the intermediate truncus, and BAL revealed increases in the neutrophils and an IgG index (BAL IgG/albumin divided by serum IgG/albumin). Biopsy specimens obtained from nasal mucosa showed epithelioid granulomas with Langerhans' giant cells and necrotizing vasculitis. Antineutrophil cytoplasmic antibodies were also positive, but no evidence of glomerulonephritis was observed. The diagnosis of limited Wegener's granulomatosis was thus made. He was treated with standard therapy (daily cyclophosphamide and glucocorticoids), but within 1 month he had complications of empyema with herpes zoster, and bronchopleural fistula. The complications resolved with appropriate treatment.

Adult↗
PubMed1994

[Gliomatosis peritonei].

Gliomatosis peritonei (GP) is the implantation of glial tissue on the peritoneal surface in patients with solid ovarian teratoma. The average age at time of biopsy was 17.4 years in this study. The largest ovarian teratoma was 30cm in diameter with an average of 21.4cm. The tumor capsules were ruptured and adhered to the omentum in 5 cases. Peritoneal dissemination was detected in one patient at the second operation 10 months after the first one. It's believed that injury to the tumor capsule may have a role in peritoneal implantation. In general, regardless of the grade of the primary ovarian teratoma, the implanted peritoneal nodules consisted exclusively of GFAP and S-100 protein positive mature astroglia. The average length of follow up was 36.2 months. One patient with GP is alive and clinically healthy 8 years and 3 months post-operatively. The authors consider GP is a benign condition and associated with an improved prognosis for solid ovarian teratoma.

Adolescent↗