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Biomedical subjects

K H Lu

Publications and source records attributed to K H Lu.

At least 37 records · Page 2Linked to original sources
PubMed1999

In vitro fertilization with flow-cytometrically-sorted bovine sperm.

An attractive feature of IVF is that fewer sexed sperm are needed than for artificial insemination. However, sperm sexed by flow cytometry/cell sorting are probably pre-capacitated, necessitating modifications to standard IVF systems for optimal success. With current procedures, the percentages of oocytes fertilized with sorted and unsorted frozen bovine sperm are similar, and events during the first cell cycle are timed similarly for sorted and unsorted sperm. However, in most cases, blastocyst production with sorted sperm was approximately 70% of controls produced with unsorted sperm. In some early studies, there appeared to be an unexplained delay of about half a day in blastocyst development. Nevertheless, some dozens of apparently normal calves, pre-sexed with 90% accuracy, have resulted from frozen embryos produced via IVF with sexed sperm. IVF also has proven useful as a bioassay for improving sperm-sorting procedures such as determining potential detrimental effects of laser power. It is likely that use of IVF in cattle breeding programs will increase considerably when sexed, frozen sperm become commercially available.

Animals↗
PubMed1999

Juvenile hormone inhibition of gene expression for cytochrome P4504C1 in adult females of the cockroach, Blaberus discoidalis.

The regulation and pattern of gene expression for cytochrome P4504C1 was measured in the fat body of adult females of the cockroach, Blaberus discoidalis. The level of CYP4C1-mRNA was high at adult emergence but disappeared after 4 days of adult life. In starved females, CYP4C1-mRNA levels declined by day 4 but increased steadily thereafter; by 25 days, the levels were nearly twice those observed at eclosion. Both the rapid early disappearance of the transcript and the starvation-related increase failed to occur following decapitation. Allatectomy also prevented the disappearance of CYP4C1-mRNA at day 4, and treatment of decapitated females with methoprene (JHA) stimulated a 70% decrease in transcript within 24 h. Injection of synthetic Blaberus hypertrehalosemic hormone (HTH) increased CYP4C1-mRNA by six-fold in the fat body of both intact and decapitated females. CYP4C1-mRNA in the fat body of males did not respond to JHA treatment. The dynamics of CYP4C1-mRNA in the fat body of females could be explained based on an inhibition of CYP4C1 expression by JH that was overcome by HTH.

Age Factors↗
PubMed1999

Cytokine and prostaglandin E2 release from leukocytes in response to metal ions derived from different prosthetic materials: an in vitro study.

Cytokines produced by leukocytes in the periprosthetic membranes surrounding joint replacements have been implicated as causal agents in osteolysis and prosthetic loosening. In this study, we used an in vitro leukocyte culture system to monitor the response of leukocytes to various metal ions and their possible roles in the mechanism of aseptic loosening. Human peripheral leukocytes were isolated and incubated with various concentrations of Co2+, Cr3+, and Ti3+ ions. Leukocyte cell counts and the levels of the tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6) and prostaglandin E2 (PGE2) released into the media were analyzed at 1 h, 3 h, and 1, 3, and 7 day intervals. The results showed that adding different metal ions into leukocyte cultures did not affect the cell counts. Exposure of leukocytes to Co2+ ion increased the release of TNF-alpha, IL-6, and PGE2. Exposure of leukocytes to Cr3+ ion did not increase the release of TNF-alpha but increased the secretion of IL-6 and PGE2. In contrast, exposure of the leukocytes to Ti3+ ions was associated with a decrease in the release of TNF-alpha and PGE2 and a minimal change in IL-6 noted after 7 days' culture. The present study elucidated the possible mechanisms involved in periprosthetic osteolysis and the inflammatory response of human leukocytes to metal ions. We found that cobalt ion is the most potent stimulant for cytokines and prostaglandin secretion by leukocytes. This elucidation, in combination with other efforts to reduce the generation of wear debris and metal ions, may improve the longevity of orthopedic implants.

Cell Count↗
PubMed1999

Trophoblastic pulmonary embolization after hysterectomy for invasive complete mole. A case report.

BACKGROUND: Trophoblastic pulmonary embolization usually occurs after evacuation of a molar pregnancy when the uterus is larger than dates and the human chorionic gonadotropin level is > 100,000 mIU/mL. It has a dramatic onset, with dyspnea, tachypnea, bilateral pulmonary infiltrates and low Po2 levels. Treatment requires supportive measures only. Intubation is rarely required. The clinical course is short-lived, with gradual improvement after 48 hours and complete resolution in 72 hours. There are no long-term sequelae. Differential diagnosis includes pulmonary embolization, fluid overload and aspiration. CASE: A 27-year-old, Caucasian woman, gravida 4, para 2, spontaneous abortion 1, developed presumed trophoblastic pulmonary embolization following abdominal hysterectomy for an invasive mole. The clinical course was typical of this condition, with spontaneous clearing in 72 hours with supportive measures only. CONCLUSION: Trophoblastic pulmonary embolization can occur following abdominal hysterectomy for invasive mole as well as after molar evacuation and should be considered part of the differential diagnosis if patients present postoperatively with acute respiratory distress.

Adult↗
PubMed1999

[Observation of microvascular casting of avulsion injured skin flap under electron microscope].

OBJECTIVE: To investigate the mechanism of necrosis of avulsion injured skin flap. METHODS: Six swine were used. An avulsed skin flap and traditional island flap were made on each hind leg of the swine respectively, and the latter was used as control. Then the microvascular casting of each flap was made routinely immediately following the injury and 72 hours later, and the vascular casting were observed under electron microscopic scanning. RESULTS: There were three characteristic changes in the avulsed skin flap: tearing of blood vessels, formation of complete thrombosis and incomplete thrombosis. If these changes were excessive in the avulsed flap, then the necrosis was the result, otherwise, the flap survived. CONCLUSION: The necrosis of avulsed flap was related to the type and extent of the damage of microvascular endothelial structure. So the degree of endothelial damage was the keypoint in the viability of avulsed flap.

Animals↗
PubMed1999

[Application of skin-stretching devices in reparative and reconstructive surgery].

OBJECTIVE: To testify the availability and the clinical efficacy of the skin-stretching device. METHODS: The skin-stretching device designed by ZHOU Li-an, which was used in the treatment of the granulation wound, the donor site of flap, and the skin defect after the excision of tumor by skin traction technique at the wound edges. RESULTS: The usage time of skin-stretching device was 15-720 minutes, it could be used preoperatively, intraoperatively and postoperatively. Followed up 16 cases for 6 to 12 months, the device was effective. CONCLUSION: The skin stretching device is practical and effective in wound closure of skin defect.

Adolescent↗
PubMed1998

Evidence for the multifocal origin of bilateral and advanced human serous borderline ovarian tumors.

Borderline ovarian tumors (BOTs), or ovarian tumors of low malignant potential, represent a distinct category of epithelial ovarian neoplasms that have a clinically more favorable outcome than invasive epithelial ovarian cancer. Histologically, BOTs and invasive ovarian carcinomas both show cellular proliferation and pleomorphism, but unlike invasive ovarian carcinomas, BOTs lack stromal invasion. Although serous BOTs are frequently confined to a single ovary at the time of diagnosis, bilateral or extra-ovarian spread occurs in 30-40% of cases. The purpose of this study is to determine whether bilateral or extraovarian serous borderline lesions are metastatic sites from the original tumor, or represent separate primary tumors. DNA specimens from multiple tumor sites and normal tissue controls were obtained in eight women with bilateral or extra-ovarian serous borderline tumors. The pattern of loss of heterozygosity at the androgen receptor locus on the X chromosome was evaluated in the multiple tumor sites. In addition, the pattern of X-chromosome inactivation was determined using HpaII restriction endonuclease digestion, followed by PCR amplification of the androgen receptor locus. Multifocality was determined when alternate patterns of X-chromosome inactivation occurred. In two of the eight patients, the left and right ovarian tumor sites had different androgen receptor alleles inactivated, indicating that the bilateral tumors derived independently. In a third patient, the X inactivation pattern in the left ovarian tumor differed from the two peritoneal implants, suggesting that the implants were separate primary tumors, and not metastatic, from the left ovarian tumor. The remaining five patients had the same pattern of loss of heterozygosity and X inactivation in the tumor sites studied. These results suggest that bilateral and advanced stage serous BOTs may be multifocal in origin. This result is in contrast to invasive epithelial ovarian cancer, which has been shown to be unifocal in origin.

Adult↗
PubMed1997

A novel 4-cM minimally deleted region on chromosome 11p15.1 associated with high grade nonmucinous epithelial ovarian carcinomas.

Prior cytogenetic and restriction fragment length polymorphism studies have demonstrated that allelic deletion of chromosome 11p is common in human invasive epithelial ovarian tumors. To construct a highly detailed deletion map of chromosome 11p, we used 13 polymorphic microsatellite CA repeat primers to identify regions harboring potential tumor suppressor genes. Twenty-three of 48 samples (48%) of invasive epithelial ovarian cancer showed LOH involving at least one locus, consistent with prior studies. None of the five mucinous tumors showed allelic deletion at any of the 13 primers, suggesting that loss of heterozygosity at chromosome 11p may not be involved in the pathogenesis of mucinous ovarian cancer. Two separate minimally deleted regions were identified in nonmucinous ovarian cancer. The first is an 11-cM region on chromosome 11pl5.5-15.3 that extends from D11S2071 to D11S988 and includes the HRAS locus. The second is a novel 4-cM region on 11p15.1, defined by marker D11S1310. Deletion of both regions at 11p15.5-15.3 and 11p15.1 is strongly associated with high grade nonmucinous epithelial ovarian cancer.

Chromosome Deletion↗
PubMed1996

Physiological effectors of hyperglycemic neurohormone biosynthesis in an insect.

Biosynthesis of hypertrehalosemic hormone (HTH) by isolated corpora cardiaca (CC) from Blaberus discoidalis cockroaches was measured for the 3-week period following adult ecdysis using an in vitro bioassay based on the incorporation of [3H]tryptophan. Synthetic rates for both males and females were highest following the molt and declined with age. Rates of HTH secretion and levels of stored HTH followed a similar pattern. We found no neural or endocrine brain effects or photophase influence on HTH synthesis. Synthesis was unaffected by treatment with 20-hydroxyecdysone or the juvenile hormone analog methoprene. In starved insects, HTH synthesis doubled and secretion increased 66% relative to fed controls.

Animals↗
PubMed1996

Arthroscopy for acute knee haemarthrosis in road traffic accident victims.

The objective of this study is to show the characteristics of acute traumatic haemarthrosis of the knee due to road traffic accidents. A prospective study was undertaken of 47 knees in 46 road traffic accident victims (14 to 74 years old), who presented with an acute haemarthrosis of the knee over 12 months. Anterior cruciate ligament (ACL) tears occurred in 51.1 per cent (24 of 47). Lateral meniscus injuries occurred in 40.4 per cent (19 of 47). There were seven injuries of the posterior segment of the lateral meniscus associated with the 18 PCL tears. Road traffic accident victims had a higher incidence of PCL and lateral meniscus injuries than did a series of athletes with injuries. High-energy and multi-directional injury and the anatomy of the posterior horn of the lateral meniscus might account for a major part of the discrepancy.

Accidents, Traffic↗
PubMed1994

[Haemolytic transfusion reaction of surgical patients due to incompatibility of Rh blood groups].

Haemolytic transfusion reactions occurred in 4 patients under plastic surgery due to incompatibility of Rh blood groups. The reaction in one of the patient occurred not only abrupt but severe and finally died of renal failure. Other three patients with delayed haemolytic reactions survived after treatment. Since more than 99.5% Chinese population is Rh positive, cross-matching on Rh blood groups is not a routine. The reactions develop usually different from typical ABO blood group haemolytic reactions and are not easy to make an early diagnose. If the surgical patients show profound anemia and haemorrhage following transfusion which could not be explained by bleeding and coagulation abnormalities, haemolytic transfusion reactions due to incompatibility of Rh blood groups might be considered.

Adult↗
PubMed1990

[Applications of bacterial pathogens to the mosquito control].

Both Bacillus thuringiensis subsp. isrealensis (Bti) and Bacillus sphaericus are common bacteria found in a variety of soil and aquatic habitats. Some strains of them can produce a protein crystal, called parasporal body (or crystal) beside the spore in the cell during sporulation, and it is toxic if eaten by mosquito larvae. As the parasporal bodies are ingested into a mosquito digestive tract, they will be digested and activated by certain enzymes in alkaline digestive juice. The activated toxins can destroy midgut epithelium and other tissues, and then the mosquitoes will be intoxicated and killed. There are some factors affecting efficiency of the toxins produced by these two mosquitocidal bacteria. First, the toxicity of the toxins will decrease as larval age and density increase. Second, difference in mosquito species will demonstrate a different tolerance to both toxins. However, larvae of Anopheles are more tolerant to Bti than those of Aedes and Culex; whereas larvae of Aedes are more tolerant to B. sphaericus than Culex and Anopheles. Environmental factors are as important as the mosquito hosts in influencing the efficiency of the toxins. For examples, raising temperature under suitable ranges may increase the toxicity of the toxins. The UV light of sunlight could inhibit activity of the toxins and therefore decrease their efficiency. Quality and depth of the water are also important environmental factors affecting toxicity of the toxins to the mosquito larvae. The precipitation of the crystal and organic materials absorbing the toxins decreases their toxicity to the mosquito larvae as well.

Animals↗
PubMed1989

c-ras-Ha gene expression is regulated by insulin or insulinlike growth factor and by epidermal growth factor in murine fibroblasts.

Although much is known about the structure of ras-encoded proteins, little is known about how expression is regulated. In serum-stimulated murine fibroblasts, c-ras-Ha mRNA levels fluctuated with the growth state but not with the position in the cell cycle. Two types of growth factors regulated c-ras-Ha expression: insulin (IN) or insulinlike growth factor I, each apparently acting through its cognate receptor, and epidermal growth factor (EGF). In quiescent cells, IN or insulinlike growth factor I induced c-ras-Ha mRNA three- to fivefold within 4 h, but thereafter the mRNA declined. By contrast, EGF had little effect in 4 h but induced the mRNA after 4 to 6 h. When quiescent cells were given serum or IN and EGF simultaneously, c-ras-Ha mRNA rose steadily, beginning 1 to 2 h after stimulation, and reached a stable five- to sevenfold elevation in 16 h. Thus, c-ras-Ha gene expression was sequentially regulated by two growth factors, one of which (IN) does not induce expression of other growth-regulated protooncogenes. A transformed derivative cell line that does not require IN for G1 progression has lost early IN-dependent but not late serum-dependent regulation. The results support the possibility that c-ras-Ha and IN action are functionally linked.

Animals↗
PubMed1989

[Expanded forehead flap for reconstruction of the nose].

Eight cases of reconstruction of nose by using skin expander are reported in detail in this article. In which, 6 cases were total nose reconstruction, 2 were upper partial reconstruction. The results were good in all cases. It is considered that the forehead flap is the place of choice in nasal reconstruction. It gives good shape contour and best color match. After application of tissue expander it could provide more skin for reconstruction, and prove more advantages in repairing the donor site. It has been observed that the reconstructed nose contour was satisfactory, with no obvious constriction after more than a year follow up. The methods and advantages of operation and some typical cases are presented.

Adult↗