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Biomedical subjects

A W Wang

Publications and source records attributed to A W Wang.

6 recordsLinked to original sources
PubMed1998

Radiographic and histologic analysis of cemented double tapered femoral stems.

The macroscopic, radiographic, and histologic features of the prosthesis-cement and cementbone interfaces and adjacent bone were studied in 21 cemented hemiarthroplasties in sheep that had lived until sacrifice at 9 months. The features were compared with those immediately after implantation of the stem in the contralateral femur. The femoral stem was a double taper that was either polished collarless, matte collarless, or matte collared. There was no prosthesis to cement debonding or cement to bone radiolucent line immediately after implantation, and there was excellent interdigitation at the cement-bone interface. After 9 months there was no evidence of prosthesis to cement debonding and no stem with definite loosening. At 9 months after implantation there was evidence of bone remodeling with new bone filling what were presumed to be gaps at the cement-bone interface from immediately after implantation. Radiolucent lines at the cement-bone interface were found to represent trabeculation of the cortical bone rather than the presence of a complete fibrous interface, which was not seen. There was no difference between stem types. Sheep have been shown to be useful in a model of cemented hip arthroplasty and, although no differences were seen between stem types at 9 months after implantation, long term differences cannot be excluded.

Animals↗
PubMed1997

Reactive oxygen species generation by seminal cells during cryopreservation.

OBJECTIVES: To test the hypothesis that conventionally used procedures for semen cryopreservation may cause an increase in the production of reactive oxygen species (ROS) by sperm or by seminal leukocytes, which may contribute to poor sperm function following cryopreservation. METHODS: Eighteen semen specimens with normal parameters from healthy male donors 22 to 40 years of age were each divided into two portions. The first portion was combined 1:1 with Test Yolk Buffer-Glycerol Freezing Medium and was frozen by gradual cooling into liquid nitrogen (-196 degrees C). The second portion was washed and the cells were resuspended in Sperm Washing Medium (SWM) and incubated at room temperature to serve as controls. After a period of treatment, frozen samples were thawed and semen cells were washed and resuspended in SWM. ROS generation by semen cells from each treatment group was measured on a luminometer. Sperm motility, sperm viability, and sperm membrane integrity were also measured in both control and freeze-thaw samples. To further assess ROS generation by semen cells during the cooling process, aliquots of washed semen cells and purified polymorphonuclear leukocytes (PMNs) were incubated separately at different temperature conditions (37 degrees C, 22 degrees C, 4 degrees C, and -20 degrees C). ROS activity in each treatment group was measured and compared with each other. RESULTS: In both semen cells and PMNs, ROS activity increased significantly during the cooling process. The highest ROS levels were recorded in both groups when cooled to 4 degrees C. The ROS levels were extremely low in samples cooled to -20 degrees C and in freeze-thaw samples, probably due to marked loss of cell viability. CONCLUSIONS: Gradual reduction of temperature during the process of semen cryopreservation can cause a significant ROS generation by semen cells. ROS is particularly elevated during cooling if the semen sample is contaminated by more than 0.5 x 10(6) leukocytes. Removal of leukocytes from semen samples or treatment with antioxidants prior to cryopreservation may improve sperm viability and function.

Adult↗
PubMed1996

Early motion after flexor tendon surgery.

Flexor tendon rehabilitation means control of the tendon healing process. It is therefore important to appreciate the physiological and biomechanical nuances of flexor tendon healing.

Biomechanical Phenomena↗
PubMedDate not supplied

Leukocytospermia in male infertility patients in China.

Recent studies have revealed a high prevalence of leukocytospermia (> 1 x 10(6) white blood cells ml-1 semen) in male infertility patients in the USA and certain European countries, and have implicated white blood cells as a cause of infertility. Since leukocytospermia may often be attributed to male genital-tract infections, its prevalence could vary widely in different populations depending on factors such as sexual practices and the prevalence of sexually transmitted pathogens. In the study described here the incidence of leukocytospermia was determined in a group of 101 male infertility patients and a small reference group of normal fertile men in Beijing, China. Seminal white blood cells (WBC) and WBC sub-populations were enumerated by peroxidase staining and immunohistological assay. Eight out of 101 (7.9%) samples from infertility patients and 0/10 samples from fertile donors were leukocytospermic. The incidence of leukocytospermia in the Chinese infertility patients was considerably lower than the 23% incidence observed in a recent study of infertility patients in the USA using a similar technique. All but one of the patients with leukocytospermia had a poor sperm count and/or poor sperm motility. However, due to the low incidence of leukocytospermia and the small number of patients in this group, a statistically significant association between leukocytospermia and poor semen quality was not attained. The simple peroxidase test correlated well with the more expensive and technically demanding immunohistological assay for detection of white blood cells in semen.

Adult↗