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Biomedical subjects

S Lu

Publications and source records attributed to S Lu.

At least 235 records · Page 13Linked to original sources
PubMed1997

Role of nitric oxide in the control of the renal medullary circulation.

1. Nitric oxide (NO) has been implicated as an important controller in the short- and long-term regulation of arterial pressure. Studies performed in our laboratory have demonstrated that chronic intravenous administration of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) selectively decreases renal medullary blood flow, causes sodium and water retention and leads to hypertension. 2. To determine the importance of the renal medullary effects in this model of hypertension, further studies were conducted to examine the influence of selective stimulation or inhibition of renal medullary NO on whole kidney function and cardiovascular homeostasis. With the use of a unique catheter to directly infuse into the renal medullary interstitial space, stimulation (bradykinin or acetylcholine) or inhibition (L-NAME) of renal medullary NO selectively increased or decreased renal medullary blood flow. 3. The changes in medullary flow in these experiments were associated with parallel changes in sodium and water excretion independent of alterations in renal cortical blood flow or glomerular filtration rate. 4. Studies were then undertaken to examine the long-term effects of selective NO inhibition in the renal medulla on cardiovascular homeostasis. Chronic infusion of L-NAME directly into the renal medullary interstitial space of uninephrectomized Sprague-Dawley rats led to a selective decrease in renal medullary blood flow that was sustained throughout the 5 day L-NAME infusion period. The decrease in medullary blood flow was associated with retention of sodium and the development of hypertension and the effects were reversible. 5. The data reviewed indicate that NO in the renal medulla has a powerful influence on fluid and electrolyte homeostasis and the control of blood pressure.

Animals↗
PubMed1997

Studies of dual promoters of mouse kappa-opioid receptor gene.

Dual promoters were identified in the mouse kappa-opioid receptor (KOR) gene. The distal promoter was located in the 5'-upstream region of exon 1 and the proximal promoter was located in the first intron of this gene. The transcription initiation site of the proximal promoter was mapped to the -93rd nucleotide position from the ATG codon in a primer extension experiment. The expression of KOR mRNAs transcribed from these two promoters in mouse central nervous system and an embryonal carcinoma cell line P19 was confirmed in a ribonuclease protection assay. In non-neuronal tissues, only the transcripts initiated from the distal promoter were detected. The biological activities of these two promoters were determined in transient transfection of P19 cells with a series of reporters, each truncated at various 5'-upstream regions. It was concluded that the distal promoter was located between nucleotide positions -990 and -570, and the proximal promoter was located between nucleotide positions -330 and -93, relative to the translation initiation codon. The presence of dual promoters in the KOR gene suggested potential regulation of KOR expression by using different promoters.

Animals↗
PubMed1997

Isolation of high molecular weight DNA for reliable genotyping of transgenic mice.

A fast and reliable method for the PCR characterization of DNA from mouse toes is described. The toes biopsied to tag the mice are incubated for 2 h in proteinase K and heated for 15 min at 95 degrees C. This DNA solution is directly used as a template for PCR amplification. The same procedure can be used for PCR analysis of DNA from other tissues in adult mice, mouse embryos and cultured cells. Because of minimal tissue manipulation, high-quality and high-molecular-weight DNA (fragments larger than 100-200 kb) is isolated. This procedure is performed in a single tube and requires no organic solvent extraction or centrifugation, allowing the isolation of high-molecular-weight DNA suitable for PCR amplification in a fast and reproducible way. Only the tissue excised during mice tagging is used and a large number of animals can be quickly and simultaneously analyzed as required to maintain a transgenic mice colony. In addition, this rapid and efficient procedure represents an alternative to other methods in which, in our experience, inhibition of the PCR amplification occurs when DNA from tail tissues is used.

Animals↗
PubMed1997

[A non-invasive method for detecting endothelium-dependent dilation].

Using high resolution ultrasound, we measured the diameter of brachial arteries at rest, during reactive hyperemia and after glyceryl trinitrate (GTN) taking in 22 healthy persons. The results showed that brachial artery dilation was present both in reactive hyperemia and response to GTN. The mean flow-mediated dilation was 13.8 +/- 3.9% increment. The mean increment of dilation in response to GTN was 24.9 +/- 9.7%. The diameters of brachial arteries during reactive hyperemia and after sublingual GTN had significant difference compared with that in baseline (P < 0.01). It indicates that increased flow may mediate endothelium-dependent vessel dilatation and GTN cause endothelium-independent vessel dilatation in normal subjects. This paper presents a new non-invasive method of detecting endothelium-dependent dilation, which is proved to be simple, secure and practical.

Adult↗
PubMed1997

[Effects of different intensity endurance training on hypothalamus-pituitary regulatory function].

Effects of different intensity endurance training on several main hormones related to exercise in the rat hypothalamus-pituitary-adrenal axis-gonadal axis were studied. The results indicated that different intensity endurance training played different roles in their synthesis and release. In 36 m/min training group, the reserve of beta-endorphine beta-EP, in hypothalamus-pituitary, the capacity of body stress and aerobic capacity were increased, whereas the stress level in exercise, the luteinizing hormone LH content were decreased as compared with other groups. It is suggested that proper endurance training may elevate the sports capacity in which beta-EP may play an important role in regulating adrenal axis and gonadal axis directly and indirectly.

Animals↗
PubMed1997

[Study on adaptive changes of myocardial ultrastructure after endurance training at different intensities in rats].

The purpose of the investigation was to determine the adaptive changes of central mechanism of aerobic metabolism and to probe the best training intensity for developing the structure and function of heart most effectively. After endurance training at different intensities (including 26 m/min, 30 m/min, 36 m/min, 42 m/min) for 16 weeks, the rats were decapitated. Left ventricle were excised soon and were then processed for electron microscopy. Morphometry was performed at image analysis system. Quantitative analysis of ultrastructure of left ventricle and capillaries indicated that the best development of mitochondria inner membrane and cristea, the maximum improvement in number of capillaries, the most obvious enlarging of capillary cavity and the most remarkable shortening of maximum oxygen diffusion distance from capillary wall to the mitochondria appeared after training at the highest speed (42 m/min). It is demonstrated that after endurance training at different intensities the ultrastructure of all training groups showed good developments in varying degrees. Furthermore, endurance training at suitably high intensity could improve adaptation of myocardium most effectively.

Adaptation, Physiological↗
PubMed1997

[Investigation on nitrosamines in the diets of the inhabitants of high-risk area for esophageal cancer in the southern China and analysis of the correlation factors].

Nan'ao County in Guangdong Province was an esophageal cancer high-risk area in the southern China. Of the suspected etiological factors in the environment, N-nitrosamines and their precursors have been received the most attention. 55 samples of the diets ingested by the inhabitants were collected and tested for volatile N-nitroso compounds and for their precursors by GC-TEA. Five kinds of N-nitrosamines (NDMA, NDEA, NPYR, NPIP and NMBzA) were detected in the samples. The average level of them was 312.0 micrograms/kg(median). The day intake of the nitrosamines was 286.5 micrograms/head/day. By the computerized stepwise regression analysis and curve fitting, we studied the correlation among the nitrosamines, the precursors and the major food items. It demonstrated that a relatively high content of volatile N-nitrosamines was present in the diets collected in the area.

Carcinogens↗
PubMed1997

[Microwave heating and neoadjuvant chemotherapy for malignant bone tumor].

Limb salvage is widely used but has different disadvantages. Attempting to establish a new limb conservative procedure, we treate patients with malignant bone tumor by intraoperative microwave heating on tumor bearing bone in place and neoadjvant chemotherapy. The tumors were localized at distal femur in 16, proximal tibia in 5, femur shaft in 2, and illia in 2. Pathological diagnosis showed osteosarcoma in 16 patents, parosteoal osteosarcoma in 4, chondrosarcoma in 3, and leiomyosarcoma in 2. The stage of tumor was II b in 18 patients, II a in 6, and III b in 3. Operative technique was wide resection for tumor in soft tissue, protecting the surrounding tissue from heat injury by copper net, and cheating tumor bone at 50 C for 15 minutes. Follow-up varied from 4 to 180 months (mean 57 months). The 5-, 10-years surviral rates were 70.19% and 54.83% respectively. Functional results of 21 patients were > 15 points by Enneking system. The advantages of the method and keeping the shape and continuity of the tumor bearing bone without osteotomy and internal fixation, controlling the time and temperature of heating treatment easily, benefiting for bone remodeling of heated bone. The indications, complications, and surgical procedure of this method were discussed in detail.

Adolescent↗
PubMed1997

[Pedicled omentum graft for improvement of late-blood supply after myocardial revascularization with Nd:YAG laser in the treatment of ischemic heart disease].

26 dogs were devided into 3 groups. Selected left coronary artery branches of all dogs were ligated to make the models of myocardial infarction. The control group of 10 dogs received ligation of selected coronary artery branches(L group) only. Eight dogs were revascularized by Nd:YAG laser (LL group), and 8 dogs were revascularized and covered with pedicled omentum. All dogs were monitored by ECG, cardiac output, fractional 86Rb uptake and histological examination. The results showed that laser channels can perfuse ischemic myocardium and recover myocardial circulation to improve cardiac function immediately. However, the laser channels were closed after 4 weeks by clot, fibrosis and scarring which caused by thermal damage of Nd:YAG laser. The late result of laser myocardial revascularization with pedicled omentum graft is more better in perfusing myocardium and improving cardiac function than sole laser myocardial revascularization.

Animals↗
PubMed1997

[Effects of the double chamber intra-aortic balloon pumping on the renal circulation].

The effects of the double chamber intra-aortic balloon (DIAB) and the single chamber intra-aortic balloon (SIAB) on the hemodynamic parameters in the kidney were studied. No negative effect of both cases was observed. Before and after removing the renal nerve system, the DIAB was used and the results had been compared. The pulse produced by pumping activized the renal nerve system and reduced the renal vascular resistance. Therefore the reduction of the renal vascular resistance is an important reason for increasing the renal blood flow during intra-aortic balloon pumping.

Animals↗
PubMed1997

[Down-regulation effect of HIM82 on respiratory burst of neutrophil].

OBJECTIVE: The early control of respiratory burst of Neutrophil (PMN) was studied by using McAb HIM82. METHODS: PMNs were isolated from healthy volunteers. Superoxide anion, Hydrogen peroxide were measured in the presence of HIM82 FMLP. Sustance P and the NEP activities was measured in the presence of HIM82 alone. RESULTS: The amount of O2.- and H2O2 produced in experimental group (by combining with HIM82) are (44.00 +/- 8.9)% (n = 8, P < 0.01) and (65.16 +/- 15.41)% (n = 8, P < 0.01) of control group respectively. The activity of NEP inactivated by PMA (without HIM82) is (43.29 +/- 9.41)% (n = 8, P < 0.05) and the activity is (66.48 +/- 15.53)% (n = 8, P < 0.05) in PMA-inactivated group with HIM82. CONCLUSIONS: The result mentioned above showed that the HIM82 monoclonal antibody exerts obvious down regulation on respiration burst induced by PMA and antagniation on inactivity of NEP. We under stand that this McAb has important regulation effect on function of PMN, it shows that the specific combination with corresponding antigen on membrane is essential for function of PMN especially for mechanism of respiratory burst of activated PMN.

Antibodies, Monoclonal↗
PubMed1997

[Total knee replacement of severe flexion contracture deformities greater than 60 degree].

The technique of total knee arthroplasty for the patients with severe flexion contractures of more than 60 degrees is not clear. Recently, We have performed 37 total knee arthroplasties in 23 patients with flexion contracture of more than 60 degrees (average 77.97 degrees). Among them, 14 knees (37.9%) with flexion contracture of more than 90 degrees, and 7 knees (18.0%) with 90 degrees flexion fusion deformities. Significant improvements occurred after averaged 4.3-year follow-up. Complications occurred in four patients: three had transient peroneal-nerve palsy, and one had temporary circulatory disturbance of the lower extremity. They recovered after conservative therapy. We consider that severe flexion contracture of more than 60 degrees is not a contraindication of TKR. Staged bone resection and thoroughly soft-tissue release of the posterior capsule and collateral ligament balance were the critical procedure. If necessary, additional distal femoral condyle resection with posterior cruciate ligment sacrifice can be considered.

Adult↗
PubMed1997

[The effects of microwave heating on osteoinduction of demineralized bone matrix in rabbits].

In order to study the change of the autograft demineralized bone matrix, twenty-four new-Zealand rabbits were randomly divided into four groups of 2, 4, 8, 12 week by sacrified time, each group had 7, 7, 5, 5 rabbits. Autoradiography was done for 2 rabbits in 2, 4 weeks respectively. The tibiae were removed by amputation at knee joint level, then they were cleansed of marrow and periosteun, cut into six pieces in length of 0.8 cm heated with microwave. Demineralized bone matrix were made by defated and decalcified, and implanted into abdomenal walls autograft. The results showed that the implants heated at 45 degrees C 30 min had same osteoinduction as control group. The 65 degrees C 30 minutes heating may reduce implant's osteoinduction slightly. The osteoinduction of the groups heated 75 degrees C for 30-60 minutes were impaired severely. The implants boiled at 100 degrees C 30 minuts had no osteoinduction at all, 65 degrees C 30 minutes may be a "safty" limit when heat treatment on bone clinically. Otherwise, bone formation ability would be reduced and remodelling was delayed.

Abdominal Muscles↗
PubMed1997

[Deletion of MTS1/p16 gene in endometrial carcinoma].

OBJECTIVE: To investigate the possible relationship between deletion of MTS1/p16 gene and progression of endometrial carcinoma. METHODS: Thirty two primary endometrial carcinoma, 7 tumor-adjacent endometrial tissue and 10 normal endometrial tissue specimens were examined for homozygous deletion of MTS1/p16 gene by polymerase chain reaction-based analysis. RESULTS: Of 32 endometrial cancer specimens, 6(18.8%) showed homozygous deletion of MTS1/p16 gene. No deletion was detected in the tumor-adjacent and normal endometrial tussues. Nor was it detected in well differentiated endometrial carcinoma. CONCLUSIONS: Deletion of MTS1/p16 gene might contribute to the progression of endometrial carcinoma and could be served as indicator for predicting prognosis.

Adenocarcinoma↗