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Biomedical subjects

J H Guo

Publications and source records attributed to J H Guo.

50 records · Page 3Linked to original sources
PubMed1993

An investigation into the mechanical and transport properties of aqueous latex films: a new hypothesis for the film-forming mechanism of aqueous dispersion system.

The effects of plasticizer, physical aging, and film-forming temperature on the mechanical and transport properties of films formed from aqueous dispersions of ethylcellulose latex were investigated. The water vapor permeability of latex films was found to decrease with diethyl phthalate to a minimum value and then to increase with diethyl phthalate at higher concentrations. Because of the decrease in free volume and the further coalescence of particles of latex polymer films in the physical aging range, the creep compliance of latex films decreased with physical aging time. Within 60 to 100 degrees C, the film-forming temperature was found to have no effect on the mechanical and transport properties of Aquacoat films. However, since many pinholes formed in the latex films when the film-forming temperature was above 100 degrees C, the water vapor permeability of latex films was higher than that of latex films formed between 60 and 100 degrees C. The formation of films from aqueous latex dispersions is suggested to proceed gradually from the top to the bottom of the latex dispersion in this study.

Cellulose↗
PubMed1993

Preoperative transcatheter hepatic arterial embolization for hepatic malignancy.

RATIONALE AND OBJECTIVES: This retrospective study was undertaken to determine clinically and histopathologically the efficacy of preoperative transcatheter hepatic arterial embolization (PTHAE) in liver malignancies. METHODS: Ten patients underwent either single or multiple episodes of PTHAE with lipiodol in an emulsion with chemotherapeutic agents. Four of the patients were thought to be unresectable before embolotherapy. Eight patients had hepatocellular carcinoma, one had cholangiocarcinoma, and one metastatic colon carcinoma. All patients subsequently underwent surgical resection. Histologic observations were made in all resected specimens. RESULTS: No viable tumor cells were recognized in three of the ten specimens, whereas extensive necrosis (70%-95%) was seen in the remaining seven patients. The four patients with tumors that were that to be unresectable before PTHAE had significant reduction in tumor burden (60%-80%) and were thought to be resectable after their embolization. Effectiveness on satellite nodules, thrombi in the portal veins, and intracapsular infiltration was histologically verified. The mean and median survival times to date have been 24.8 and 24.5 months, respectively. CONCLUSIONS: Preoperative transcatheter hepatic arterial embolization is a useful procedure that, in this small patient series, converted unresectable liver tumors into potentially resectable lesions.

Aged↗
PubMed1993

[Studies on laxative function of maren soft capsule].

The experimental results show that the Maren soft capsule can increase the amount and weight of the stool of normal mice and model mice with dry stool, promote the advanced percentage of charcoal powder in the small and large intestines of mice, enhance the movement of the smooth muscle of isolated ileum of guinea pigs under physiological conditions or low temperature, as well as strengthen the intestinal movement in rabbits.

Animals↗
PubMed1993

[The effect of zinc glycyrrhizate on toxicity and anticancer activity of cisplatin in mice].

The preventive effects of Zn Glycyrrhizate (Gly-Zn) on lethal toxicity, nephrotoxicity, hemotoxicity, testicular toxicity and anticancer activity of cisplatin (CDDP) were investigated in mice. The toxicity of CDDP evaluated by the above criterion was significantly reduced by preadministration of Gly-Zn 400 mg.kg-1.d-1 x 5 (P < 0.05 or P < 0.01). The protective effects were better than bismuth subnitrate (BSN) which has been studied previously (0.05 < P < 0.1). The metallothionein (MT) level in the liver, kidney, heart and cancer of mice treated with one of these compounds were determined. The results showed that the levels of MT induced by Gly-Zn were significantly increased in liver and kidney (P < 0.05). It was just in conformity with the conclusion that the best protective effect appeared in the groups treated with preadministration of Gly-Zn. These results suggest that increased MT synthesis in the liver and kidney may be involved in the protective effect of Gly-Zn on the toxicities produced by CDDP. The experiments also showed that Gly-Zn did not affect the anticancer effect of CDDP in vitro and in vivo, while the MT level was not increased in cancer (P < 0.05), so Gly-Zn might improve the therapeutic index of CDDP.

Animals↗
PubMed1992

[Relationship between plasma and urinary platinum pharmacokinetics with cisplatin nephrotoxicity in breast cancer patients].

In 25 cycles of 20 breast cancer patients who received 26 cycles of high-dose cisplatin (100 mg/m2, iv drip), the urinary Alb, IgG and NAG values were elevated above normal. These patients were divided into low-nephrotoxicity and high-nephrotoxicity groups by the degree of renal dysfunction. Of these patients 35% showed high-nephrotoxicity. They had significantly higher plasma and/or urinary Pt peak levels during cisplatin infusion than did those with low-nephrotoxicity. And 70-80% of the patients developed significant nephrotoxicity when the urinary Pt level rose up to greater than 40 micrograms/ml or plasma Pt level greater than 4 micrograms/ml. It is very important to keep the urinary and plasma Pt level below 40 micrograms/ml and 4 micrograms/ml respectively in order to reduce the nephrotoxicity. It is suggested that the urine output be maintained over 300 ml/hr for 2 hours before and after the completion of infusion and greater than 100 ml/hr in the following 3 days. This helps keep the cisplatin-induced nephrotoxicity in less severe and the function of kidney easy to recover.

Acetylglucosaminidase↗
PubMed1991

Influence of physical aging on mechanical properties of polymer free films: the prediction of long-term aging effects on the water permeability and dissolution rate of polymer film-coated tablets.

The effects of physical aging on the water permeation of cellulose acetate and ethylcellulose, the mechanical properties of ethylcellulose, and the dissolution property of hydroxypropyl methylcellulose phthalate were investigated. The water permeabilities of cellulose acetate and ethylcellulose and the dissolution rate of hydroxypropyl methylcellulose phthalate were found to decrease with physical aging time after being quenched from above the glass transition temperatures to sub-Tg temperatures. The gradual approach toward thermodynamic equilibrium during physical aging decreases the free volume of the polymers. This decrease in free volume is accompanied by a decrease in the transport mobility, with concomitant changes in those properties of the polymer that depend on it. The effects of long-term aging on the dissolution rate and water permeabilities of these polymers can be estimated from a linear double-logarithmic relationship between the mobility properties and physical aging time. The existence of the linear double-logarithmic relationship can be derived from the Williams-Landel-Ferry equation, the Doolittle equation, Struik's model, and Fujita's relationship between diffusion and free volume.

Cellulose↗
PubMed1989

[Transesophageal supra-burst pacing to terminate paroxysmal supraventricular tachycardia].

A new cardiac stimulation mode (transesophageal supra-burst pacing) to terminate paroxysmal supraventricular tachycardia (PSVT) in the clinical and electrophysiologic laboratory is first described for the first time in this paper. All the parameters of this method were as follows: (1) pulse duration: 10 ms; (2) pulse rate: 250-300 bpm; (3) pulse amplitude: 26-43 volts; (4) number of pulse from each supra-burst pacing: 3-5 beats. The results of terminating PSVT using this method showed that (1) among 112 patients with PSVT treated by this method, PSVT was terminated in 103 cases and failed to terminate in 9 cases; (2) during each PSVT successfully terminated by this method, once (90.4%), twice (6.6%), thrice time (3%) supra-burst pacing were respectively used. These data indicate that transesophageal supra-burst pacing is a safe, simple and useful method to terminate PSVT.

Adolescent↗
PubMedDate not supplied

Automated percutaneous lumbar discectomy: a prospective multi-institutional study.

PURPOSE: A prospective study in 10 independent hospitals from 1992 to 1994 evaluated automated percutaneous lumbar discectomy (APLD) with a newly designed percutaneous instrument. MATERIALS AND METHODS: One thousand five hundred eighty-two APLD procedures were performed in 1,525 patients with disc herniation or back pain. Mean follow-up after APLD was 18.3 months. Follow-up of at least 1 year was available in 1,474 patients. One thousand two hundred eighty-nine patients had sciatic pain and 185 had back pain only. Eight hundred twenty-two patients had symptoms for less than 2 years, 652 for more than 2 years. One thousand two hundred sixty-two patients were older than 60 years, 212 were younger than 60 years. Nine hundred fifty patients had disc protrusion, and 357 had sequestration. Forty-eight patients had disc or longitudinal ligament calcification. Twenty-two had previous surgical discectomy. All discectomies were done with use of a straight needle with the patient in the lateral decubitus position. RESULTS: Success rate (measured by Hijikata's criteria) was 83% at 1 year. Success was significantly greater for protrusion versus sequestration (86% vs 72%, P < .001); for back pain alone versus leg and back pain (89% vs 80%, P < .005); for duration of symptoms less than 2 years versus more than 2 years (85% vs 79%, P < .005); and for age younger than 60 years versus older than 60 years (84% vs 76%, P < .01). Among postsurgical patients, success rate was 77% (17 of 22 patients). The only complication was discitis (0.06%, nine patients). Technical success at L5-S1 was 99% (795 of 800). CONCLUSION: APLD with Teng's instrument has excellent results. Indications may include back pain alone. A straight needle can be used at L5-S1 in most patients, with proper positioning.

Diskectomy, Percutaneous↗
PubMedDate not supplied

Expression of testis specific ankyrin repeat and SOCS box-containing 17 gene.

Human ASB-17 (Ankyrin Repeat and SOCS Box-containing 17) is a recently identified gene belonging to the ASB family, isolated from testis cDNA library. Human ASB-17 is expressed exclusively in testis among 16 tissues, revealed by Northern blot. Mouse Asb-17 was shown to be expressed from the third week post birth to adult by semi-quantitative RT-PCR analysis. In situ hybridization on frozen sections demonstrated that Asb-17 is expressed in spermatogenic cells in adult mouse, but not in Leydig cell and epididymis in adult mouse. ASB-17 proteins are highly conserved in mammals including human, mouse, rat, Canis familiaris and Macaca fascicularis.

Adaptor Proteins, Signal Transducing↗