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Biomedical subjects

P He

Publications and source records attributed to P He.

155 records · Page 9Linked to original sources
PubMed1985

[Effect of microwave contraception on human serum testosterone and luteinizing hormone].

Using home-made match kits and radioimmunoassay, both serum luteinizing hormone (LH) and testosterone (T) were measured in 53 healthy adult males using microwave contraception and 76 normal fertility males as control. The results showed that in contraceptive group the serum T level was significantly decreased (p 0.0001), while serum LH was apparently elevated (p 0.01) as compared whith the normal controls. Furthermore, the longer exposure duration the lower serum T declined and the higher serum LH increased (p 0.001). The present study suggests that the microwave dose used for contraception seems to cause damage in Leydig cell function in terms of T production, and then influence endocrine function of testis. The progressively increased LH level also indicates certain degree damage of the Leydig cells. However, the damage might be reversible. The results may be useful for further clinical investigation.

Androgens↗
PubMedDate not supplied

Phenacetin O-deethylation in extrahepatic tissues of rats.

Phenacetin O-deethylation is a marker reaction of CYP450 1A2 activity. The drug-metabolizing enzyme is constitutively expressed in liver. In this study, an in vivo rat model for assessment of extrahepatic metabolism was used to investigate phenacetin O-deethylation and the alterations in the disposition of phenacetin due to the loss of liver function. Rats were divided into the model and normal control groups. The model was established according to our previously described method. The concentrations of phenacetin and its major metabolites acetaminophen, glucuronate-acetaminophen and sulfate-acetaminophen in plasma and urine were determined by HPLC. 30 min after intravenous administration of 0.16% phenacetin 10 mg x kg(-1), plasma acetaminophen in the model group was only 3.6% of that in the control group (0.09+/-0.04 microg x mL(-1) vs 2.49+/-0.85 microg x mL(-1), n = 8). 30 min after intragastric injection of 0.4% phenacetin 30 mg x kg(-1), plasma acetaminophen formation was very slight, about 8.6% of plasma phenacetin in the model group (0.74+/-0.43 microg x mL(-1) acetaminophen vs 8.57+/-8.42 microg x mL(-1) phenacetin) and 6.8% in the control group (1.06+/-0.59 microg x mL(-1) acetaminophen vs 15.47+/-7.21 microg x mL(-1) phenacetin, n = 8); no significant differences were observed in plasma phenacetin, total acetaminophen and the ratio of acetaminophen to phenacetin between control and model groups. In the urine collected for 3 h after intravenous administration of 0.16% phenacetin 10 mg x kg(-1), the total recovery of acetaminophen (as free, glucuronate- and sulfate-acetaminophen ) in the model group was 4.6% of that in the control group (4.47+/-4.27 microg vs 96.63+/-8.50 microg, n = 6), but phenacetin recovery in the model group was 9 times higher than that in the control group (15.03+/-17.72 microg vs 1.66+/-0.50 microg). The results indicate that phenacetin O-deethylation in the extrahepatic tissues and the first-pass metabolism of the probe compound seem to be negligible in rats, but the renal excretion of phenacetin, as a compensation, dramatically increases in model rats.

Acetaminophen↗
PubMedDate not supplied

Sustained release chitosan microspheres prepared by novel spray drying methods.

Modified spray drying methods, especially a novel w/o/w emulsion-spray drying method, were developed to prepare chitosan microspheres with a sustained drug release pattern. Release of the model drugs cimetidine and famotidine, from the microspheres prepared by the emulsion-spray drying methods, was greatly retarded with release lasting for several hours, compared with drug loaded microspheres prepared by conventional-spray drying or emulsion methods where drug release was almost instant. The slow release of drug was partly due to the poor wetting ability of the microspheres which floated on the surface of the dissolution medium. The addition of a wetting agent increased the release rate significantly. The coating of the microspheres with gelatin decreased the rate of release of drug in the presence of wetting agents.

Aerosols↗
PubMedDate not supplied

Extended effects of human papillomavirus 16 E6-specific short hairpin RNA on cervical carcinoma cells.

Most cervical carcinomas express high-risk human papillomavirus (HPV) E6 and E7 oncogenes. Small interfering RNA can mediate sequence-specific inhibition of gene expression in mammalian cells. To find a most effective short hairpin RNA (shRNA) for HPV16 E6 messenger RNA (mRNA) and investigate the extended effects of the HPV16 E6 shRNA on cervical carcinoma cells, we stably transfected SiHa cells with four shRNA expression vectors (E6A-D). HPV16 E6A shRNA was found to be the most efficient in our study, which caused the reduction of HPV16 E6 mRNA to 10% in SiHa cells but did not reduce HPV18 E6 mRNA expression in HeLa cells. We subsequently demonstrated that E6A could stably express shRNA and effectively reduce HPV16 E6 and E7 viral genes expression in SiHa cells for more than 4 months. After E6 and E7 repression, there was a dramatic accumulation of p53, p21, and hypophosphorylated pRb proteins in cells. Furthermore, cell proliferation, colony formation ability, tumorigenicity, and in vitro cell invasive capability were suppressed substantially in E6A-transfected cells. These results suggest that the use of shRNA expression vector may be a potential approach for the treatment of persistent HPV infection and HPV-positive cervical carcinoma.

Animals↗
PubMedDate not supplied

Temperature dependence of the O2-oscillation pattern in the filamentous cyanobacterium Oscillatoria chalybea and in Chlorella kessleri.

Five characteristic discontinuities of the pattern of oxygen evolution have been detected for the filamentous cyanobacterium Oscillatoria chalybea in the temperature range of 0 degree C to 30 degrees C. The temperatures at which these discontinuities occur are: approximately 5 degrees C, approximately 11 degrees C, approximately 15 degrees C, approximately 21 degrees C and approximately 25 degrees C. The calculated initial 5-S state distribution, the miss parameter and the fraction of the fast transition S3-->So + O2 are affected. The discontinuities are observed at the same transition temperature also for Chlorella kessleri hence are not specific for the cyanobacterium. Based on these studies it is concluded that the not vanishing oxygen signal under the first flash of a flash train in Oscillatoria cannot have its origin in interactions between oxygen-evolving complexes. A decrease of temperature should slow down the expected charge exchanges, improve the oscillations thus reduce or lower the first two oxygen amplitudes of the oscillatoria pattern. Lowering of the temperature improves the oscillations but does not lower the first O2 signal of the pattern.

Activity Cycles↗
PubMedDate not supplied

Seeds of Trichosanthes kirilowii, an energy-rich diet.

The kernels of Trichosanthes kirilowii seeds contain a green oil which makes up for 62% of their dry matter. This oil consists up to 95% of triglycerides, 2% of glycolipids, 1.3% of phospholipids and 1.8% of chlorophylls. As fatty acid components the triglycerides, glycolipids and phospholipids contain the unsaturated fatty acids linoleic and oleic acid and the saturated palmitic acid. In the triglycerides 19% of the C18:3 acid occur with the configuration delta9 cis, delta11 trans, delta13 cis. This acid is called trichosanic acid and is absent in glycolipids and phospholipids which contain instead another C18:3 fatty acid, which has conjugated double bounds and occurs with an amount of 21% and 3%, respectively. Typically, these oil seeds contain in addition up to 30% of their dry matter proteins and up to 2.5% mono- and oligosaccharides. The monosaccharides consist of rhamnose, galactose and glucose and the oligosaccharides represent a mixture of tri- and tetrasaccharides.

Carbohydrates↗
PubMedDate not supplied

Capacity of enzymes of the euphorbiacea Aleurites montana involved in CO2-fixation, compared to plants having C3-, C4- and Crassulacean acid metabolism.

Capacities of phosphoenolpyruvate carboxylase (PEP-Co), ribulose bisphosphate carboxylase (Rubisco), NADP+ malic enzyme (ME) and of malate dehydrogenase (MDH) were measured in the Euphorbiacea Aleurites montana, grown under 700 ppm CO2 for four weeks prior to enzyme extraction. For comparison Bryophyllum daigremontiana (CAM). Saccharum officinarum (C4) and Capsicum frutescens (C3) were treated in the same way. PEP-Co capacity of Aleurites was in the range of 12-, that of Capsicum approx. 26 nmol x min(-1) x mg protein(-1), without significant influence of the light period or CO2-treatment. In contrast, the activity of the enzyme from Saccharum was, depending on the duration of light, 160- respectively 96 times higher than that of the tung-oil tree. In Bryophyllum a rather low activity in the morning was increased during the day to approx. 230 nmol x min(-1) x mg protein(-1) in plants grown in the greenhouse and to approx. 115 nmol x min(-1) x mg protein(-1) in those from the growth chamber. Malate was hardly detectable in extracts of Aleurites, whereas it was high in Bryophyllum, depending on the light period. The ratio of average PEP-Co to Rub-Co capacity was high for the CAM-plant (20:1), somewhat lower for sugar cane (10:1), but almost at equality for Aleurites (0.9:1) and chilli (0.8:1). For the NADP+ malic enzyme, low capacity (20 to 28 nmol x min(-1) x mg protein(-1)) was found for Aleurites and for Capsicum, whereas it was 10 to 17 times higher in Saccharum. In Bryophyllum, the activity was up to 80 nmol x min(-1) x mg protein, dependent on light period. MDH capacity was extremely high in all plants investigated. Highest rates (10-20 micromol x min(-1) x mg protein(-1)), were obtained for Bryophyllum, followed by sugar cane and Capsicum with 5-8 micromol x min(-1) x mg protein(-1). Again, the lowest capacity was found in extracts of Aleurites with approx. 1.3 to 1.6 micromol x min(-1) x m protein(-1). Thus, in Aleurites montana no indication for C4- or Crassulacean acid metabolism was obtained. Therefore, the earlier observed very efficient uptake of CO2 cannot be explained by a high expression of the PEP-Co protein, known to occur in CAM- and C4-plants.

Capsicum↗
PubMedDate not supplied

Breast cancer diagnosis by laser transmission photo-scanning with spectro-analysis (report 4).

The laser transmission photo-scanning (LTPS) is a non-invasive imaging technique for breast examination that is based on the fact that tumors have a different light transmission rate than normal tissues. The LTPS equipment used in our study was improved by adopting a dual (red and infrared) beam scan method. LTPS results of 19 patients are presented here, together with their mammography results. Sixteen positive cases were detected by LTPS, while mammography yielded 15 out of 19 cases. In our study, LTPS images were similar in accuracy to those of X-ray mammography. This dual-wavelength LTPS system improved the tumor sensitivity and specificity of transmission images. It may be possible to present pathophysiological data in addition to anatomical data, to distinguish malignant from benign tumors.

Adult↗
PubMedDate not supplied

Construction of a laser transmission photo-scanner: pre-clinical investigation (report 2).

A prototype high-speed laser transmission photo-scanner using a 1 mm He-Ne laser beam and corresponding detector was constructed. Signals obtained from the detector were digitalized and stored in floppy disks by a micro-computer and displayed as color-coded pictures on the CRT monitor. The data were analyzed and absorption in the tissue was shown in a histogram. Breast tissue was simulated using pork, ham, lard, and cheese in a pre-clinical investigation. Normal breasts of volunteers were also examined. When disks of varying sizes were inserted into ham and cheese of various thicknesses, it was found that disks closer to the beam's point of entrance produced the best images, while disks in the center and those closer to the exit were poorly detected. Disks close to the surface were better detected than central lesions. Laser transmission images of normal breasts of twelve volunteers were symmetrical but often nonhomogeneous because of the complexity of breast tissue.

Breast↗
PubMedDate not supplied

Laser transmission photo-scanner: clinical application in breast tumor detection (report 3).

The increasing number of breast cancer patients in Japan necessitates the development of a useful screening method. Previous studies using a laser transmission photo-scanner for breast lesions showed its use to be feasible in screening for small lesions in small breasts. An increase in the power of the laser beam, however, is necessary to detect small tumors in larger breasts or large tumors. In cases where mammography was compared with laser transmission images, the latter were compatible with published data. More precise examination of laser transmission photo-scanning with the addition of spectro-analysis is the next step.

Breast Neoplasms↗