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Biomedical subjects

S Lu

Publications and source records attributed to S Lu.

396 records · Page 22Linked to original sources
PubMed1984

Activation of chemical carcinogens by cultured human fetal liver, esophagus and stomach.

Cultured fetal human stomach, esophagus and liver activated benzo[a]pyrene (BP), aflatoxin B1 (AFB) and certain N-nitrosamines into metabolites that bound to cellular DNA. When the 3 organs were compared the highest level of activity was observed in the stomach. The interindividual variation was 10-fold and the amount of carcinogen-DNA adducts did not correlate with the sex or age of the fetus. The reaction products between BP or AFB and cellular DNA were investigated in liver explants. The carcinogen-DNA adduct patterns were identical to those observed in adult human tissues; BPDEI-Gua being the major adduct formed by BP and 2,3-dihydro-2-(7'-guanyl)-3-hydroxy-AFB by AFB. The results indicate that fetal organs can metabolize those oncogenic compounds at an early stage of the development, and that the metabolic pathways and DNA adducts are quite similar to those in experimental animals in which the compounds are carcinogenic.

Aflatoxin B1↗
PubMed1979

Formation of carcinogenic N-nitroso compounds in corn-bread inoculated with fungi.

DMNA, DENA and MBNA are formed in corn-bread which has been inoculated with the most common species of fungi found in foodstuffs of Lin Xian County, Henan Province, such as F. moniliforme, A. flavus and others, and then, added with small amount of NaNO2 after a few days of incubation. These carcinogenic N-nitroso compounds can induce cancer of the liver or/and esophagus in experimental animals. Results of the present study show the capability of some fungi to produce chemical carcinogens as well as mycotoxins in contaminated food, and thus, open a new field of research in cancer etiology.

Aspergillus flavus↗
PubMedDate not supplied

Binding of radioiodinated influenza virus peptides to class I MHC molecules and to other cellular proteins as analyzed by gel filtration and photoaffinity labeling.

In order to determine how T cell-presented peptides associate with the antigen binding sites (desetopes) of class I major histocompatibility complex (MHC) molecules and how they might be scavenged from an endogenous processing pathway for transfer to those molecules, we characterized the binding of two synthetic peptides restricted by HLA-B37 or HLA-A2 to class I MHC molecules and to cellular proteins of histotyped cell lines, by gel filtration and photo-affinity labeling techniques. In gel filtration binding studies, each peptide associated with immunopurified class I MHC molecules from cells with its restricting, histotype, but little was bound to class I MHC molecules from cells without the restricting histotype and none was bound to bovine serum albumin. After crosslinkage of a radioiodinated photoreactive derivative of influenza virus nucleoprotein peptide NP(336-355Y) and immunoprecipitations with antibodies to class I MHC molecules, that peptide was found to bind to immunopurified class I MHC molecules from HLA-B37+ but not HLA-B37- cells. Binding of the [125I]NP peptide increased from 6 to 12 hr of incubation and was competed by unlabeled, NP peptide but not by HLA-A2-restricted, influenza virus matrix MA(57-73). The principal microsomal membrane proteins binding [125I]NP were about 65, 45 and 33 kD.

Affinity Labels↗
PubMedDate not supplied

Androgens and estrogens modulate 5-HT1A and 5-HT1B agonist effects on aggression.

Intermale offensive aggressive behavior is facilitated by gonadal steroids and inhibited by serotonin (5-HT), presumably through its effects at 5-HT1A and 5-HT1B receptor sites. To examine the interaction between these neuroendocrine and neurochemical regulatory systems, CF-1 male mice were gonadectomized and implanted with silastic capsules containing either diethylstilbestrol (DES, a synthetic estrogen), the nonaromatizable androgens methyltrienolone (R1881) or dihydrotestosterone (DHT), or testosterone (T). Two weeks later, they were given 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, a 5-HT1A agonist; 0.1 or 1.0 mg/kg), CGS12066B (a 5-HT1B agonist; 4.0 or 8.0 mg/kg), 0.1 or 1.0 mg/kg 8-OH-DPAT + 4.0 mg/kg CGS12066B, or vehicle, and tested for aggression. In the presence of DES, the higher 8-OH-DPAT dose given in combination with CGS attenuated aggression in comparison to vehicle controls. When given nonaromatizable androgen (R1881 or DHT), all drug treatments except 0.1 mg/kg 8-OH-DPAT significantly reduced offensive attack behavior. In the presence of T, which provides estrogenic and androgenic stimulation, aggression scores were significantly reduced when males were given the high dose of 8-OH-DPAT or CGS12066B, as well as in the 1.0 mg/kg 8-OH-DPAT + CGS12066B condition. Assessments of changes in motor behavior showed significant impairment when 8.0 mg/kg CGS12066B was administered across all hormonal conditions, indicating that reductions in offensive aggression in these treatment groups were nonspecific. The results demonstrate differential effects of the steroidal environment on the ability of 5-HT1A and 5-HT1B agonists to modulate aggression, with estrogens producing a more restrictive environment than androgens for serotonergic inhibition of male-typical aggressive behavior.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMedDate not supplied

Potential effectiveness of stored cord blood (non-frozen) for emergency use.

Bone marrow has been used for a number of years to assist patients who have accidentally received potentially lethal levels of irradiation. The intent of the transplant is to replace the victim's own bone marrow that has been injured from the irradiation or to act as temporary support to allow the patient's own marrow to recover. Following the Chernobyl disaster, some victims received bone marrow that was HLA matched or partially matched. However, donor marrows were difficult to obtain in adequate numbers; as a substitute for bone marrow, frozen fetal liver cells were used as a source of hematopoietic stem cells. The use of fetal livers, however, was unsuccessful. Human umbilical cord blood, currently considered an excellent source of hematopoietic stem cells, was not used at Chernobyl. For several years, we have been able experimentally to keep SJL/J mice alive with the use of human umbilical cord blood after the animals received lethal levels of irradiation. This finding suggests that under certain conditions human cord blood does not have to be HLA matched to facilitate rescue from irradiation. In addition, there are reports of unmatched HLA cord blood being used successfully for marrow transplantation. If human cord blood does not have to be matched for HLA, there may be emergency cataclysmic circumstances where the availability of umbilical cord blood may be of considerable value. To simulate a clinical situation such as a nuclear accident, in which human cord blood might serve as a source of stem cells for marrow transplantation, we attempted to rescue immunocompetent mice after 900 cGY of irradiation with the use of (nonfrozen) human cord blood stored in a blood bank. The blood was stored under routine conditions (3-6 degrees C) for 5 and 7 days in special bags that allow transmission of oxygen. Following lethal levels of irradiation, the cord blood was administered to the animals and a significant survival rate was obtained.

Adoptive Transfer↗
PubMedDate not supplied

The effect of accelerated aging on the wear of UHMWPE.

Oxidative degradation of UHMWPE has been found to be a cause of elevated wear rate of the polymer in total joint replacement leading to failure of these devices. In order to evaluate long term stability of polymers, various accelerated aging methods have been developed. In this study, wear rates of shelf aged UHMWPE and "accelerated aged" UHMWPE were compared using a multi-directional pin-on-plate wear test machine in order to evaluate the effect of the accelerated aging on wear. Wear factors of the aged materials were found to depend on their density, which is a measure of oxidation level. Finally, accelerated aging was calibrated against shelf aging in terms of wear rate.

Journal Article↗
PubMedDate not supplied

Quality of life after small intestinal transplantation and among home parenteral nutrition patients.

BACKGROUND: The purpose of the study was to quantify changes in the quality of life of small bowel recipients before and after transplantation and of home parenteral nutrition (HPN)-dependent patients before and after therapy. We examined quality of life across multiple areas of function including physical, social, and emotional indices. METHODS: The Quality of Life Instrument in the form of a self-administered questionnaire was completed voluntarily by the recipients of small intestinal transplants and by a cohort of HPN-dependent patients. RESULTS: Small intestinal transplant recipients reported significant improvement in the quality of their life and function. They also rated their quality of life and function during the pretransplant, TPN-dependent period to be worse than before the development of chronic intestinal failure. Similarly, HPN recipients reported significant worsening across most areas of quality of life when they compared their premorbid period to the HPN-dependent state. CONCLUSIONS: TPN dependence causes significant impairment in the quality of life in most areas of functioning. In contrast, small intestinal transplantation restores the quality of life among recipients with functioning grafts.

Adult↗
PubMedDate not supplied

The change of C-fos expression in ovariectomized rats following electroacupuncture treatment--an immunohistochemistry study.

The roles of electroacupuncture (EA) in regulating the function of ovulation in rat have been investigated; however, the systematic study for the involvement of neural population of central nervous system (CNS) in acupuncturing the ovariectomized rat for promoting functional recovery has not been well understood. The present research was designed to examine, by C-fos immunocytochemistry, the distribution of Fos labelled neuron in CNS after acupuncturing the point of "Zhong-Ji (RN3)", "Guan-Yuan (RN4)", "San-Ying-Jiao (SP6)" and "Zi-Gong (EXCA1)" in ovariectomized rat. The area occupied by Fos protein labelled neuron, two hours after ovariotomy, was detected in medial preoptic nucleus (MPN), lateral preoptic nucleus (LPN), suprachiasmatic nucleus (SCN), paraventricular nucleus of the hypothalamus (PANH), medial amygdala nucleus (MAN), periventricular nucleus of the hypothalamus (PVNH), ventromedial nucleus of the hypothalamus (VNH), and arcuate nucleus (AR). The C-fos immunoreactive labelled neurons disappeared two weeks later following ovariotomy. The rat, recovering for two weeks after ovariotomy, received EA, and many specific Fos labelled cell were observed in LPN, PVNH, VNH, SCN and especially in AR, PANH and MPN, but not any labelled neuron could be found in MAN. No obvious C-fos expression was shown in these areas in the control group and EA group without ovariotomy. These results indicate that the above structures involved in regulating the function of hypothalamus-pituitary-ovarian axis and EA could modulate this function through effects on the above nuclei.

Animals↗
PubMedDate not supplied

Outreach, consolidation, and networking: Columbia's approach to successful integration of laboratory services in California.

At the forefront of integrated laboratory services, Columbia Bay Area Healthcare Network's Lab Link provides a unique approach to operating hospital-based laboratories in today's heavily penetrated managed-care environment. Columbia recognizes that a combined strategy of laboratory consolidation, outreach, and networking is essential to compete successfully with commercial reference laboratories for local and statewide contracts. Implementing this model enables hospital laboratories to produce high quality, cost-effective test results while increasing volume and reducing duplication. When hospital laboratories consolidate and network with local and regional laboratories, inpatient and outpatients information is cross-fertilized through a web of information systems. Patients information can then be accessed easily and monitored throughout the continuum of care. The goal of this article is to provide hospital laboratories with a streamlined approach to structuring and delivering services while maintaining a competitive edge in the tumultuous healthcare market. The future of laboratory services within the hospital setting lies in the aggressive use of three elements--consolidation, outreach, and networking--to ensure quality service as well as economic viability.

California↗
PubMedDate not supplied

Angiogenesis and vasodilation in skin warts. Association with HPV infection.

BACKGROUND: Angiogenesis is required for tumour growth. Since human papillomavirus (HPV) infection is associated with the development of neoplastic lesions, the aim of this study was to determine the possible association between HPV infection and angiogenesis in benign tumours. MATERIALS AND METHODS: Specimens of skin warts which were either negative for HPV types 1, 2, 3 and 4 (HPV-ve; n = 15), or positive for HPV2 (HPV+ve; n = 19) were compared with normal skin (NS, n = 10). Vascularity and inflammation were assessed in consecutive sections. vWF-positive blood vessels were classified as small or large using a cut-off value of 50 microns diameter. RESULTS: Vascularity values for small vessels increased significantly from NS to HPV-ve warts and from HPV-ve to HPV+ve warts. Large vessels were found only in warts and their abundance was not related to HPV status. No significant association was found between vascularity and inflammation or between vascularity values for small and large vessels. CONCLUSIONS: The development of skin warts is accompanied by angiogenesis and vasodilation and these two processes may be independently regulated. Further increased angiogenesis, but not vasodilation, is associated with the presence of HPV type 2 DNA.

Analysis of Variance↗