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Biomedical subjects

J Sun

Publications and source records attributed to J Sun.

At least 541 records · Page 30Linked to original sources
PubMed1996

Nonparametric tests of tumor prevalence data.

This note discusses the statistical analysis of tumor prevalence data arising from tumorgenicity experiments with focus on the comparison of different treatments. In this situation, the commonly used tests can be classified into two types: interval-based tests and model-based tests (Hoel, D. G. and Walburg, H. E., 1972, Journal of the National Cancer Institute 49, 361-372; Dinse, G. E. and Lagakos, S. W. 1983, Applied Statistics 32, 236-248). It is known that the results obtained from the interval-based tests may vary according to the choice of intervals and, for the model-based tests, it may be difficult to justify the assumed model. A computationally simple alternative to these tests is proposed; this alternative is not interval-based and makes no strong model assumption. The results of a simulation study comparing the proposed test with other tests are presented and suggest that the proposed approach is quite satisfactory.

Animals↗
PubMed1996

Purification, characterization and cDNA cloning of a novel anticoagulant of the intrinsic pathway, (prolixin-S) from salivary glands of the blood sucking bug, Rhodnius prolixus.

The salivary glands of the blood sucking insect, Rhodnius prolixus, have an anticoagulant, prolixin-S, which was reported as a specific inhibitor of intrinsic coagulant pathway. Prolixin-S was purified from the salivary glands extract of Rhodnius prolixus by gel filtration and anion exchange HPLC by assaying prolongation of activated partial thromboplastin time (APTT). The isolated protein specifically inhibited factor IXa-catalyzed activation of factor X in the presence of Ca2+ and phospholipids irrespective of the presence or absence of factor VIIIa. The anticoagulant factor had red color and a specific absorbance peak at 402 nm and thus it was identified as a heme protein. A Rhodnius prolixus salivary gland cDNA library was prepared, screened with an antibody against prolixin-S and its complete cDNA sequence was determined. cDNA and deduced amino acid sequences showed that prolixin-S is a novel anticoagulant of 19,922 Da, which has no sequence homology with any other anticoagulant reported so far.

Amino Acid Sequence↗
PubMed1996

Endometrial progesterone receptors and markers of uterine receptivity in the window of implantation.

OBJECTIVE: To compare the expression of endometrial P receptors (PR) levels with markers of endometrial receptivity during the window of implantation. DESIGN: Prospective, controlled study to examine endometrial PR and three cycle-specific integrins in endometrial biopsies obtained during the window of implantation. SETTING: An academic teaching hospital. PATIENTS: One hundred seventy-five endometrial biopsies from regularly cycling women with luteal phase defect (LPD; group 1; n = 80), medically treated LPD (group 2; n = 16), minimal and mild endometriosis with aberrant alpha v beta 3 expression (group 3; n = 21), fertile controls (group 4; n = 26), and infertile controls (group 5; n = 32). MAIN OUTCOME MEASURE: Immunohistochemical staining intensity of each antigen using the semi-quantitative grading system (HSCORE), compared using analysis of variance with Scheffe's correction. RESULTS: Among the five groups studied, nuclear PR expression was significantly elevated in glandular epithelial cells from tissue samples with histologic delay > or = 3 days consistent with luteal phase deficiency (LPD; group 1). Failure of PR down-regulation was associated with aberrant alpha v beta 3 integrin expression. Medical correction of LPD was associated with return of normal endometrial histology, normal integrin expression, and the loss of epithelial PR, similar to controls. The other two cycle-dependent integrin markers, alpha 1 beta 1 and alpha 4 beta 1, were not different between groups. In women with aberrant alpha v beta 3 and "in phase" endometrium, epithelial PR expression was not different from controls. CONCLUSIONS: The establishment of normal endometrial receptivity appears to be tightly associated with the down-regulation of epithelial PR. Histologic delay, consistent with LPD, is associated with a failure of PR down-regulation and the lack of normal markers of endometrial receptivity. Occult uterine receptivity defects (aberrant beta 3 expression in otherwise normal histology) are regulated differently, suggesting alternate mechanisms also exist which influence endometrial receptivity.

Adult↗
PubMed1996

The effect of oral contraceptive pills on markers of endometrial receptivity.

OBJECTIVE: To determine if oral contraceptive (OC) usage alters expression of integrins associated with endometrial receptivity. DESIGN: Immunohistochemical staining intensity for integrins was compared in frozen sections of endometrial tissue specimens obtained from women with normal ovulatory cycles (n = 23; cycle days 20 to 24 based on LH surge) and from those taking oral contraceptives pills (n = 23; cycle days 5 to 27). SETTING: University-based outpatient infertility clinic. RESULTS: Constitutive integrin expression in the endometrium (alpha 2 beta 1, alpha 3 beta 1, alpha 5 beta 1, alpha 6 beta 1, and alpha 6 beta 4) was similar in OC users and normally cycling individuals, except for an increase in epithelial alpha 3 beta 1 in OC users. Oral contraceptive use was associated with significant alterations in cycle-dependent integrin expression (alpha 1 beta 1, alpha 4 beta 1, and alpha v beta 3). Specifically, we observed increased glandular alpha 4 beta 1, and decreased alpha v beta 3 expression. The P-regulated alpha 1 subunit was present in both groups. Increased stromal alpha v and beta 3 and decreased alpha 3 beta 1 and alpha 6 beta 1 staining was observed in OC users. CONCLUSIONS: Expression of those integrins most closely associated with endometrial receptivity, alpha v beta 3 and alpha 4 beta 1, is altered in the glandular epithelium of women taking OCs. Stromal integrin expression in OC users also differs from that in cycling women. These alterations in epithelial and stromal integrin expression suggest that impaired uterine receptivity is one mechanism whereby OCs exert their contraceptive actions.

Adult↗
PubMed1996

Plasma concentrations of carotenoids and tocopherols in male long-term tobacco chewers, smokers and nonusers.

Plasma carotenoid and tocopherol concentrations of men, aged 25 to 55 years, who were long-term chewers, smokers, or tobacco nonusers were determined. Tobacco users had either chewed (n = 11) or smoked (n = 23) for > 15 years. Nonusers (n = 10) had never smoked > 1 pack or chewed > 34 g. Food energy, mono- and poly-unsaturated and saturated fats, cholesterol, vitamin A, vitamin E, and carotenoid intakes of the three groups were not significantly different. Chewers and smokers reported consuming significantly less cryptoxanthin, found primarily in some fruits, and had significantly lower plasma cryptoxanthin levels than nonusers. Nonusers had significantly higher concentrations of plasma alpha-tocopherol than smokers; whereas those of chewers were intermediate. Nonusers had significantly higher concentrations of plasma gamma-tocopherol and total tocopherols than chewers or smokers. Plasma delta-tocopherol concentrations of the groups were not significantly different. Nonusers had significantly higher levels of beta-carotene than smokers but not chewers. Plasma lutein and lycopene concentrations of all groups were not significantly different. Dietary intakes of total carotenoids and tocopherols of the three groups were not significantly different, yet nonusers had higher plasma concentrations of total and most individual carotenoids and tocopherols than smokers with values for chewers being intermediate.

Adult↗
PubMed1996

Timing of surgery after acute myocardial infarction.

OBJECTIVE: We wished to determine if timing of surgery, when other co-morbid variables are controlled, influenced outcome after operations for acute myocardial infarction. DESIGN: Between 3/20/1990 and 6/17/1994, data was prospectively collected on 338 patients undergoing operation for either evolving infarcts (n=73) or up to 21 days after infarction (mean 7.9 days). SETTING: Tertiary hospital referral center. PATIENTS: Infarction was diagnosed by CK enzymes or EKG Q-waves preoperatively in 338 patients undergoing surgery. The mean age of the patients was 66.1 years (SD+/-10.5 years), 76 had emergency operations immediately after catheterization (50 following PTCA complications), 223 had urgent operations, and 39 were elective. INTERVENTIONS: Seventy-three had preoperative ballon pumps, and 259 had one or more mammary artery bypasses with a mean of 3.27 (SD+/-1.0) distal anastomoses. RESULTS: In-hospital and 30-day survival rate was 95.6% (323/338). Of the 73 variables evaluated by step-wise logistic regression analysis, the multivariate independent preoperative predictors of death were: aortic valve regurgitation, chronic pulmonary disease, preoperative diuretic administration, preoperative balloon pump, preoperative inotropes, and the need for additional concomitant noncardiac surgery. Including the operative variables, the predictors were: preoperative balloon pump, preoperative inotropes, the presence of left main stenosis, preoperative renal failure, chronic pulmonary disease, valve disease, ischemic arrhythmia, pump perfusion time, valve surgery, and homologous blood transfusion volume required. When the postoperative variables were included, the predictors were: preoperative inotropes, postoperative balloon pump, postoperative epinephrine, postoperative permanent stroke, and postoperative acute renal failure. The time between infarction and operation was not an independent prediction (p>0.4) in any of the logistic regression models. CONCLUSION: Early operation after acute infarction is not in itself a risk factor, rather comorbid disease and preoperative hemodynamic status determine outcome after surgery.

Hemodynamics↗
PubMed1996

[Enhancement of tumor growth after partial hepatectomy and blood transfusion].

Female adult BUF rats (6-8 week) received sham operation (Sham), 70% hepatectomy (PH); Sham or PH with blood transfusion (BT or PH+BT). BUF 7316A hepatoma cells were inoculated subcutaneously in the neck of rats on the operation day. Tumor size was measured from day 7 to 20 after inoculation. Sera and splenic adherent cells harvested on day 5 from Sham and PH rats were added into mixed lymphocyte cultures (MLR). The result showed that tumor growth in PH or BT rats was significantly promoted as compared to that in Sham rats (P < 0.01, P < 0.05). The most marked enhancement of tumor growth was observed in PH+BT rats (P < 0.001). Sera and splenic adherent cells from PH rat significantly inhibited MLR (P < 0.05). These results suggest that partial hepatectomy and blood transfusion are responsible for the enhancement of tumor growth. Some immunosupperassive factor might be produced in the process of liver regeneration, and blood transfusion might have an additive immunosuppressive effect.

Animals↗
PubMed1996

[Early changes in cardiac function and beta-ARs in heart after severe scalds in rat].

The changes in left ventricular function and ventricle beta-adrenoceptors (beta-ARs) were measured in rat undergoing a full thickness scalded burn of skin of 30% total body surface area. The results showed that there were a significant decrease in left ventricular systolic pressure (LVSP), maximum rising and falling rate of left intraventricular pressure (LV +/- dp/dtmax) and density of ventricular beta-ARs. Correlation analysis showed that the change in beta-ARs density correlated with the change in LVSP, LV +/- dp/dtmax positively.

Animals↗
PubMed1996

[Ovarian metastasis in uterine cervical cancer: analysis of 17 cases].

OBJECTIVE: To investigate the incidence of ovarian metastasis in cervical cancer, especially in early FIGO stages. METHODS: Seventeen cervical cancer patients with ovarian metastasis treated at Cancer Hospital, Chinese Academy of Medical Sciences from 1958 to 1994 were retrospectively analysed. The diagnoses of all patients were confirmed by operations and pathologic examinations. RESULTS: The incidence of ovarian metastasis in cervical cancer was 0.07% in squamous cell carcinoma and 1.81% in adenocarcinoma (P < 0.05). In early stages (stage l-I), the incidence of ovarian metastasis in adenocarcinoma was higher than that in squamous cell carcinoma (2.2% VS 0.08%, P < 0.05). In patients treated by surgery, the rate of ovarian metastasis in adenocarcinoma was also higher than that in squamous cell carcinoma (7.8% VS 1.6%, P < 0.05). 10 of the 17 cases had macroscopic metastasis and 7 had microscopic metastasis. 11 patients (58.8%) were with bilateral ovarian involvement. Uterine corpus invasion and retroperitoneal lymph node involvements were high risk factors for ovarian metastasis in cervical cancer. The prognosis of cervical cancer patients with ovarian metastasis was poor, the 5-year survival rate in this study being only 17.6%. CONCLUSIONS: Patients with cervical cancer are threatened with the risk of ovarian metastasis, especially in adenocarcinoma. Conservative treatment of the cervical cancer with reservation of the ovary should be further investigated.

Adenocarcinoma↗
PubMed1996

[Determination of serum free amino acids and ammonia in pregnant women with severe pregnancy induced hypertension].

OBJECTIVE: To determine the changes of serum free amino acids and ammonia in pregnant women with severe pregnancy induced hypertension (PIH) and to evaluate its significance. METHODS: 16 kinds of free amino acids and ammonia in maternal serum were measured by auto-amino acid-analyzor in 33 cases with severe PIH and 29 normal pregnancies. Haematocrit (HCT) and hemoglobin (Hb) in some of the samples were also determined. The correlation between HCT, Hb and the total free amino acid were studied. RESULTS: The group with PIH showed the following changes: amino acidemia and ammonemia; high aromatic amino acidemia; high threonine, arginine, glycine, cystine and glutamic acidemia. The level of glutamic acid was obviously higher in the eclampsia patients than that in the preeclampsia ones. There existed a negative correlation between the quantities of the total amino acid and HCT and Hb in PIH group. CONCLUSION: There were amino acidemia and ammonemia in PIH patients. The high levels of some amino acids might be related with the pathogenesis of hypertension and the cerebral symptoms.

Adult↗
PubMed1996

[Evaluation of radiotherapy for state I ovarian carcinoma].

To investigate the role of radiotherapy for stage I epithelial ovarian carcinoma, the results in 91 patients treated from 1970-1989 were retrospectively analysed. There were 60 patients treated by operation combined with chemotherapy, 31 patients by operation combined with chemotherapy and radiotherapy. Patients in both groups were comparable with regard to age, clinical stage, histology grade, type of operation and chemotherapeutic regimen. The 5-year actuarial survival rate was 78.3% for those receiving additional radiotherapy and 72.4% for those without additional radiotherapy. The recurrence rate was 32.2% with a median recurrence time of 34 months in the former group while 60.6% and 18.6% months for the latter. Radiotherapy did not confer survival advantage in the treatment of stage I ovarian cancer, but it could decrease recurrence rate and delay onset of recurrence.

Adenocarcinoma, Mucinous↗
PubMed1996

[The ultrastructure of the Eustachian tube].

To observe the ultrastructure of mucous membrane of Eustachian tube in human being, ninteen human's Eustachian tube from various ages, were divided into tympanic segment, isthmus and pharyngeal segment and observed under SEM. The results showed that the epithelium of Eustachian tube consisted of ciliated cells, nonciliated cells and goblet cells. At the isthmus, the bone and cartilage junction, the cells got crowded, and there were more and more goblet cells from tympanic side to pharyngeal side, as well as the cilia of ciliated cell leaned towards the pharyngeal side. The upper one third part of Eustachian tube was covered mostly by nonciliated cells, the floor and lower parts were ciliated cells. It was concluded that the upper parts of Eustachian tube's wall played an important role in maintaining equation of pressure in middle ear, and the floor and lower parts in providing an active mucociliary mechnism. The defence system of the Eustachian tube mucous membrane had developed during the fetal stage and was well established at birth.

Adult↗
PubMed1996

[Combined treatment for advanced vulvar cancer].

OBJECTIVE: To investigate the combined treatment of surgery and radiotherapy as well as prognosis significance for advanced vulvar cancer. METHODS: Fourty-three cases of advanced vulvar cancer treated by surgery and pre- and post-operative radiation were retrospectively analysed. Twenty-nine patients were treated by preoperative radiotherapy with surgery, fourteen by surgery with postoperative irradiation. 43 patients were underwent radical vulvectomy with inguinal lymphadenectomy (20 cases) and with biopsies of inguinal lymph nodes (16 cases). Partial resection of vagina, distant urethra or anus were done concurrently with radical vulvectomy in 41 patients with adjacent organs invaded. The effects with various doses of radiation for local tumor were compared and the recurrences in patients with tumor resected completely and with microresidual disease after surgery were analysed. RESULTS: The overall 5-yr survival rate was 45.0% for this group (by Kaplan-Meier). Patients received preoperative irradiation with dose maximum (Dm) > or = 40 Gy had a better tumor regression than with Dm < 40 Gy (75.0% vs 18.2%, P < 0.05). 4 out of 6 patients received postoperative irradiation Dm > 40 Gy were survived over 5-yr, in contrast, 2 out of 8 patients with Dm < or = 40 Gy were survived over 3 and 5 years respectively. The local recurrence rate was 25.0% in patients with no residual disease and 68.4% with microscopic tumor in the surgical margins or nearby (P < 0.05). CONCLUSION: The results demonstrate that the dosage of irradiation and the thoroughness of radical surgery are the most important factors influencing the prognosis.

Adult↗
PubMed1996

[Experimental study on adenosine hypothesis of bradyarrhythmias occurring in myocardial hypoxia and its clinical significance].

Important role of endogenous adenosine in the pathogenesis of hypoxic bradyarrhythmias was verified experimentally both in vivo and in vitro models of myocardial hypoxia in 180 guinea pigs and 40 rabbits by using enzyme differential spectrophotometry, synchronous quantitative analysis of correlated factors and adenosine antagonist. Results disclosed that endogenous adenosine in hypoxic myocardium increased markedly from a gram myocardial tissue 5.8 +/- 1.7 nmol of the control group to 27.5 +/- 2.0 nmol of 5% O2 inhalation group (P < 0.01). Sinus bradycardia and A-V block induced by injection of exogenous adenosine were closely akin to those caused by myocardial hypoxia both in ECG characteristics and dose-response curve. Both of their His electrograms showed prolongation of A-H interval but nochange of H-V interval, indicating the same locality of conduction block. Synchronous quantitative analysis of 3 related factors revealed a correlation coefficient of 0.99 (P < 0.01) between endogenous adenosine and bradyarrhythmias, denoting a subordinate instead of coordinate relation. Moreover, cause and effect relation could be shown between them from the result that aminophylline (50 mg, i.p.) could abolish completely II degrees-III degrees A-V block which would otherwise be bound to occur after inhalation of 5% O2. The present study is the first in vivo experimental verification of adenosine hypothesis throughout the world which not only can well explain those atropine-resistant cases, but also opens up the way to an entirely new therapeutic strategy for these kinds of bradyarrhythmias, i.e. instead of M-cholinoceptor blocker, adenosine antagonist (methylxanthines, e.g. aminophylline) should be prescribed.

Adenosine↗
PubMed1996

[Screening for the new formulation of 25% ascorbic acid injection and studies on its stability].

Two optimum new formulation of 25% ascobic Acid injection were selected by screening with the method of orthogomal design. To estimate the stability of these new formulations, samples were subjected to accelerated stability test at elevated temperatures. The rats of coloration and variation in the concentration of the new formulation under anaerobic degradation were studied. Experimental results indicate that the rule of coloration of ascorbic acid injection may be represented by the following regression equation T = T(o)-kt2 where To is the initial transmittance of the injection, T denotes the transmittance at time t, and k denotes the regression coefficient. The variation in the concentration of the two new formulations under amaerobic degradation was found to proceed in the pseudo-zero order reaction. The discoloration and content of ascorbic acid for two injections were predicted by accelerated stability test with the classical isothermal method and one-point method respectively. The discoloration shelf-life was about 39 months for R I and 36 months for R II, the content shelf-life about 40 months for R I and 38 months for R II respectively.

Animals↗
PubMed1996

[A study of mechanism by which tumor growth was induced by partial hepatectomy].

In this study, 18 BUF rats with 7316 A liver cancer burden were divided into three groups. Groups A underwent simple laparotomy, group B had 70% hepatectomy, and group C with laparotomy plus TGF-beta . Splenic adhesive cells and serum of postoperative day 5 in both group A and B were added into mixed lymphocellular culture and CCL-64 cell culture, TGF-beta was also added into MLC and 7613 A liver cancer culture. It was found that in group B and C the growth rate of tumor cells was greatly accelerated (P < 0.01); whereas MLC and CCL-64 cell proliferation was inhibited by the serum and splenic adhesive cells from group B (P < 0.05). TGF-beta also significantly inhibited MLC through it had no effect on 7316 A liver cancer cells. The authors came to the conclusion that there was the activity of TGF-beta in the serum of the rats with partial hepatectomy which inhibits the proliferation of host immune cells.

Animals↗