Safety studies of the intraperitoneal injection of E1A--liposome complex in mice

The HER-2/neu (also called c-erbB-2) proto-oncogene is overexpressed in many human cancer cells, including those of breast cancer and ovarian cancer. We have previously shown that adenovirus 5 E1A inhibits HER-2/neu transcription and functions as a tumor suppressor gene in HER-2/neu-overexpressing cancer cells. Liposome-mediated E1A gene transfer suppresses tumor development and prolongs survival of tumor-bearing mice. In support of a phase I clinical trial of an E1A-liposome complex administered to patients with HER-2/neu-overexpressing breast of ovarian cancer, we conducted a series of studies to evaluate the safety of intraperitoneal injection of E1A in normal mice. The cumulative doses used were from five to 40 times the DNA-lipid starting dose proposed for the phase I clinical trial. In this dosing range, the administration of the E1A-liposome complex had no adverse effects on renal, hepatic and hematological parameters studied. No major organ pathologic changes were observed. We concluded that intraperitoneal administration of E1A-liposome complex at the proposed dose would not be expected to produce significant toxicity. The E1A-liposome clinical trial was recently approved by the Recombinant DNA Advisory Committee and Food and Drug Administration for a phase I trial in patients with HER-2/neu-overexpressing breast and ovarian cancer.

[The frequencies of the vitamin D receptor gene alleles in adults of Han nationality in Beijing area]

Vitamin D receptor (VDR) gene is considered as one of candidate genes related to the genetic basis of bone and mineral metabolism. In order to determine VDR genotypes, we analysed the polymorphisms, or genotypes of Bsm I, Apa I, and Taq I restriction enzymes, by PCR technique in 223 unrelated healthy adults of Han nationality in Beijing area. Some of the VDR genotypes were also confirmed by Southern blotting analysis. We discovered that Chinese had high frequencies of b, a, T alleles, as high as 95%, 75%, and 95% respectively, which were different from those in Caucasians and Japanese, but similar to those in Koreans (P > 0.05). This difference gave us further insight into the different pathogeny of osteoporosis in various ethnics.

[Normal spinal changes of bone mineral density in 445 individuals: assessment by quantitative computed tomography]

Spinal BMD was measured by QCT in 445 normal individuals aged 10-80 including 190 males and 255 females, which were divided into age-groups by every ten years. Statistic results showed that peak bone mass reached at 10-19 age-group for both male and female and that BMD assessed by QCT in females was not lower than that in males and BMD declined with increasing age. In females, BMD results in this study were different from those in USA. An acceleration bone loss was predominantly shown in the period after 40-49 age group. Among many factors related to bone loss, we consider that estrogen change may play a most important role for the remarkable bone loss in our country.

Identification of a specific DNA region required for enhanced transcription of HER2/neu in the MDA-MB453 breast cancer cell line

Overexpression and/or amplification of the HER2/neu gene has been shown in roughly 30% of breast cancer patients. Increased levels of HER2/neu mRNA in some breast cancer cell lines is partially caused by increased gene transcription. In MDA-MB453 human breast cancer cells, an activated trans-acting factor is involved in the increased transcription of HER2/neu by mediating its effects through a specific DNA region in the HER2/neu promoter. A methylation interference experiment showed a novel sequence for protein-DNA interactions. Three polypeptides of approximately 110, 70, and 35 kD interact with this DNA element. This region of the human HER2/neu promoter is highly conserved in the rat and mouse promoters and was shown to be capable of mediating transcriptional trans-activation in HER2/neu-overexpressing MDA-MB453 cells while having little effect in a control cell line that expresses basal levels of HER2/neu. Knowledge on interactions between this DNA element and nuclear protein factors may help us better understand the molecular mechanisms regulating HER2/neu overexpression in breast cancer cells.

[Predictable value of fasting blood glucose level for the incidence of non-insulin-dependent diabetes mellitus]

In order to investigate the predictable value of fasting blood glucose (FBG) level for the incidence of non-insulin-dependent diabetes mellitus (NIDDM), 638 nondiabetic subjects who were investigated in 1986 (including 341 subjects with normal glucose tolerance and 297 subjects with impaired glucose tolerance) were reexamined in 1992. The results showed that the 6-year-incidence of NIDDM was significantly increased with rising of baseline FBG level. After adjusting for age, sex and body mass index (BMI), proportional hazard regression analysis showed that FBG level in impaired glucose tolerance group was positively associated with the development of NIDDM (P = 0.0001). Subjects with mean FBG level of 5.19 mmol/L had a higher risk of developing NIDDM than subjects with mean FBG level of 4.61 mmol/L (RR 2.1, 95% CI 1.19-3.74, P = 0.01). The risk ratio of NIDDM was further increased in the group with mean FBG level of 6.l5 mmol/L (RR = 2.9, 95% CI 1.79-4.59, P = 0.0001). The result indicates that FBG level is an independent risk factor for the development of NIDDM.

Mutant SV40 large T antigen as a therapeutic agent for HER-2/neu-overexpressing ovarian cancer

The HER-2/neu gene is frequently amplified and/or its protein product, p185, is overexpressed in a number of human cancers. Overexpression of p185 correlates with poor prognosis and low survival rates in ovarian cancer patients. We previously found that the K1 mutant of SV40 large T antigen inhibits rat neu promoter and suppresses mutation-activated rat neu transformation in mouse fibroblasts. We show here that K1 also inhibits human HER-2/neu promoter in human ovarian cancer cells. To investigate whether K1 can suppress HER-2/neu transformation and thus is a potential therapeutic agent, we used an orthotopic ovarian cancer model in which mice were injected intraperitoneally with HER-2/neu-overexpressing human ovarian cancer cells to induce tumor development. The tumor-bearing mice were then treated with K1-liposome complex weekly. We found that liposome-mediated K1 gene transfer decreased the p185 protein level by K1 expression in these cancer cells and significantly prolonged mice survival; about 40% of these treated mice were alive for more than 1 year without any tumor development. On the other hand, the animals from control groups that did not receive this gene therapy all developed tumors and died within 7 months. The results indicate that liposome-mediated K1 gene transfer is able to suppress tumor development from HER-2/neu-overexpressing ovarian cancer cells in mice.

Reproducibility of nutrient intake in a food frequency questionnaire used in a general population

This study evaluates the reproducibility of nutrient intake in a 45-item food frequency questionnaire (FFQ). The FFQ was mailed in 1980 to persons eligible to participate in a large cohort study on diet and cancer risk; a follow-up version with 75 food items was mailed in 1988 to selected original participants. A random sample of 500 men and 500 women from the New York State general population was selected from individuals who responded to both waves of the study. The subjects' 1988 responses were compared with their original 1980 responses; Pearson's correlations ranged from 0.25 for retinol to 0.55 for vitamin C with or without supplements and vitamin E with supplements in women. Reproducibility of nutrient intake in this questionnaire indicates that brief FFQs may be a useful tool to study nutrient intake and chronic disease relationships, although they are subject to substantial measurement error and dietary change.

[The injury of liver sinusoidal endothelial cells in a rat's isolated liver perfusion (ILP) model for regional chemotherapy]

To observe the pathological changes of liver sinusoidal endothelial cells, the regional perfusion with different dosage of 5-FU was performed by using modified rat's model of ILP. The results demonstrated that ILP with over maximum tolerence dosage of (MTD) 5-FU resulted in irreversible damage of liver and endothelial cells. The endothelial cells were more fragile than liver cells. The changes of TXA2 and PGI2 balance play an important role in the process of damage of endothelial cells.

The retrospective study on high risk factors of subphrenic infection after hepatectomy

In order to identify the high risk factors that determine subphrenic infection after hepatectomy, 187 liver resections performed during January, 1985 to December, 1990 in Department of Surgery of Tongji Hospital were reviewed. Thirteen patients developed subphrenic infection with the incidence of subphrenic infection being 6.95%. The results of retrospective study on 187 liver resections demonstrated that the high risk factors related to subphrenic infection after hepatectomy were as follows: (1) The extent of liver resection was associated with subphrenic infection. (2) The incidence of subphrenic infection after liver resection of primary liver cancer patients with hepatic cirrhosis was higher than that of non-cirrhotic patients. (3) Intraoperative estimated blood loss greater than 1500 ml was found to be a significant risk factor in the development of postoperative subphrenic infection. (4) Adequate postoperative drainage of subdiaphragm and the raw surface of the liver was one of critical factors of decreasing subphrenic infection after liver resection.

[Baseline hypertriglyceridemia, a risk factor for non-insulin dependent diabetes mellitus: a 6-year follow-up study of 432 nondiabetics]

The relationship between baseline fasting plasma triglycerides level (FTG) and the incidence of non-insulin-dependent diabetes mellitus (NIDDM) within 6 years were investigated in 432 Chinese nondiabetics. They were identified by oral glucose tolerance test (OGTT, oral 75 g glucose) in Daqing diabetes survey in 1986. 220 subjects were men and 212 women. Among them 226 had normal glucose tolerance and 206 impaired glucose tolerance. The measurement of fasting plasma lipids and glucose were performed at the baseline examination and after 6-year follow-up. Six-year incidence of NIDDM in the highest triglycerides tertile group (top tertile Q3, mean = 2.5 mmol/L) was 2.3 times (38.6% vs 16.6%, P < 0.01) as compared with that of the lowest triglycerides tertile group (first tertile Q1, mean = 0.7 mmol/L). The difference of 2-hour blood glucose level in OGTT (OGTT BG2h level) between Q1 and Q3 was 2.4 mmol/L (mean = 7.6-10.0 mmol/L) after 6 years. Multivariate general linear regression analysis demonstrated that the FTG level was positively associated with the OGTT BG2h level after 6 years (P = 0.0335) after controlling the age, sex, fasting blood glucose (FBG) and body mass index (BMI). Therefore this result indicates that FTG level is an independent risk factor for the development of NIDDM in this population.

[Changes in surface microcirculation of extensor digitorum longus tendon after ischemia-reperfusion of rabbit hindlimbs]

The circulation was stopped by tourniquet in one rabbit hindlimb. After 2 or 5 hr of ischemia, the hindlimb was reperfused. During the first 1 hr of reperfusion, dynamic changes in surface microcirculation of extensor digitorum longus tendon were observed by using intravital microscopy. Particular attention was paid to leukocyte-endothelium adhesion and microvascular perfusion condition. It was found that 1) the number of leukocytes adherent to the venular endothelium of ischemic tissue significantly increased following reperfusion and the degree of increases appeared to be directly related to the duration of ischemic period; 2) reperfusion after 5 hr of ischemia could result in the formation of "no reflow phenomenon" in the ischemic tissues, including "primary no reflow" and "secondary capillary perfusion failure". These results suggest that 1) leukocyte-endothelium adhesion may contribute to the development of ischemia reperfusion injury; 2) in the limbs undergone 5 hr of ischemia, not all injuries that occur after ischemi-reperfusion can be attributed to ischemia reperfusion injury. The injury seen some in areas may be produced by ischemia alone, and in others ischemia-reperfusion-secondary ischemia injury may be responsible.

HER-2/neu-targeting gene therapy--a review

The HER-2/neu (also named c-erbB-2) oncogene is known to be overexpressed in many human cancers, including breast, ovarian, lung, gastric and oral cancers. In animal models, HER-2/neu overexpression was shown to enhance malignancy and metastasis phenotypes. Repression of HER-2/neu overexpression suppresses the malignant phenotypes of HER-2/neu-overexpressing cancer cells, suggesting that HER-2/neu may serve as an excellent target for developing anti-cancer agents. We have previously shown that the adenovirus-5 (Ad5) E1a gene products and the SV40 large T antigen (large T) inhibit transcription of the HER-2/neu promoter and accordingly suppresses transformation induced by HER-2/neu. In this review, we summarize our recent findings on using cationic liposomes or an Ad vector to deliver E1a or large T into tumor-bearing mice. Our results indicate that both cationic liposomes or an Ad vector can efficiently deliver E1a or large T into tumor cells in mice, and this results in suppression of tumor growth and longer survival of the mice.

[Clinical application of immediate intraoperative expansion technique]

Since June 1992, 14 patients with skin or soft tissue defects from resection of scar or nevus were treated using the technique of immediate intraoperative expansion with good results. The operative procedure, indications and key points are discussed. We concluded that immediate intraoperative expansion may be accepted as a simple, safe and effective technique for the repair of the skin defects, which can be sutured directly under great tension.

[Changes and trend prediction in cancer morbidity of urban residents in Beijing]

Data from a long-term cancer morbidity registry and notification system were analyzed dynamically. A theoretical model of grey system was established based on time-series changes in cancer morbidities to predict its trend by the year of 2001 in Beijing. Results show cancer morbidities in Beijing will increase yearly from 1991 to 2001, and overall morbidity rate of malignant tumor will increase to 179.9/100,000 from 162.5/100,000. Proportions of malignant tumor in different sites will change greatly. Morbidities of lung cancer and breast cancer will increase rapidly, of liver and colon-rectal cancer shoes an increasing trend, too, of esophageal and cervical cancer will decline steadily, and of stomach cancer will begin to decline. All these facts laid a scientific basis for the study on cancer prevention and control.

Reproducibility of food intake in a food frequency questionnaire used in a general population

This study evaluates the reproducibility of food intake reports in a 45-item self-administered food frequency questionnaire (FFQ) used for a diet study in a large cohort in New York State. The first FFQ was mailed in 1980, and a followup version containing 75 food items was mailed in 1988 to the eligible original participants. Reproducibility was evaluated by comparing the subjects' 1988 responses with their original 1980 responses. Spearman's correlations ranged from 0.27 (nuts other than peanuts) to 0.56 (summer squash) in men and from 0.25 (tomatoes) to 0.51 (summer squash) in women. Analyses stratified by age, education, marital status, body mass index, cigarette smoking, alcohol drinking, and special diet revealed few substantial differences in correlations. The moderate reproducibility of foods in this questionnaire indicates that brief FFQs may be a useful tool to study food intake and chronic disease relationships in this population.

[The preliminary experiences of diagnosis and treatment for hypercalcemia crisis--clinical analysis of 23 cases]

This article report a study of 23 cases of hypercalcemia crisis resulting from primary hyperparathyroidism (18 cases), carcinoma (4 cases) and vitamin D intoxication (1 case). In addition to the symptoms of primary diseases, the patients with hypercalcemia crisis often had anorexia, nausea, vomiting, polydipsia, polyuria, psychoneurotic symptoms, arrhthmia. The severity of the symptoms was proportional to the degree of hypercalcimia. Serum calcium concentration of patients in hypercalcemia crisis should be equal or higher than 3.75 mmol/L (15 mg/dl) or serum ionized calcium higher than 1.88 mmol/L. Treatment hypercalcemia crisis consisted of rapidly lowering the serum calcium level by various measures while actively treating the primary diseases. Our experience is to supply normal saline intravenously or orally to increase the extracellular fluid and to enhance excretion of the urine calcium by administrating furosemide. In this paper, serum calcium concentration of 5 patients with hypercalcemia crisis treated with salmen calcitonin was reduced in varying degrees. The above mentioned treatment would be beneficial to the alleviation of the crisis and the preparation for operative treatment.

[The diagnosis of primary hyperparathyroidism--analysis of 134 cases]

This article reports the diagnostic experiences of 134 cases of primary hyperparathyroidism (PHPT) confirmed by operation and pathologic examination. The clinical presentations were divided into 4 types: (1) 75 cases (56.0%) with bone resorption; (2) 47 cases (35.0%) with bone lesions plus urinary calculus; (3) 8 cases (6.0%) with urinary calculus only and; (4) 4 cases (3.0%) with hypercalcemia only. Bone lesions included bone resorption, osteomalacia and osteoporosis. Stones at multiple sites in the urinary tract or nephrocalcinosis were found in 41 cases. The measurement of ionized calcium was much more sensitive and accurate than the total calcium assay with the positive rate of 95.3% and 73.4% respectively. The concentration of plasma iPTH was high in the whole group (n = 84), the mean value was 21.4 +/- 17.9 times higher than that of the normal control group. For the localization of the affected parathyroid gland, instiat examination was by neck ultrasonography which gone a positive predictive value of 81.5% (43/53), 99mTc-MIBI scan showed positive rate 94.1% (16/17). The CT scan of the chest was used when ectopic location in mediastinum was highly suspected. If the first operative exploration failed to find the affected parathyroid gland, we performed the determinations of iPTH with samples taken from internal jugular vein through selective venous catheterization; the coincidence rate was found to be 85.2% (23/27).

[Experimental studies on microcirculation of the hindlimb after ischemia and reperfusion in the rabbits. 1. Establishment of an in vivo method for observing microcirculation using tendon surface microvessels on the dorsum of the foot]

The blood supply system of the extensor digitorum longus tendon in the rabbit hindlimb is observed by the aid of dye injection technique and dissecting microscope. We find that the segment proximal to metatarsophalangeal joint of this tendon is an ideal site for observation of in vivo microcirculation. In this site, there are abundant microvessels on the surface of the tendon, and as red microvessels are on white tendon, it forms a sharp contrast. In addition, the tendon is only covered by skin and little loose connective tissue, so it is easy to expose. On the bases of abovementioned findings, a new in vivo method for observing microcirculation in the rabbit hindlimb is developed. In our experiences, the advantages of this method are as follows: (1) It is simple and convenient; (2) The time required for preparation is short (about 10-15 min), and the observation period can be extended (over 6 h.); (3) Surgical trauma is not serious; (4) The image is clear. This method opens up a new way to using rabbit hindlimb ischemia model to study microcirculation changes in vivo following reperfusion after extremity ischemia.

Influence of vibration on microdiameter measurements using a laser-charge-coupled device system

The influence of vibration on dynamic measurements of microdiameters using a laser diffraction-CCD detection system is studied. The theoretical analysis indicates that the influence of vibration on the diffraction pattern of a measured object introduces significant errors into its diameter measurement, and the improvement can be approached by using a TEM(00) Gaussian incident beam instead of the usual uniform beam. The experimental results of these cases are also presented and in good accordance with the theoretical analysis.

[Comparative study on tissue morphology and vascular changes of skin xenografts, allografts and autografts after transplantation]

In this study, the tissue morphology and the vascular changes of skin xenografts from the rats to the rabbits were compared with that of skin allografts and autografts simultaneously transplanted to the same recipient by the use of histological examination and dye injection. The results suggested that the xenografts were incapable of becoming vascularized, and exhibited necrosis on the third day, while early vascularization was demonstrated in the allografts and autografts. The xenografts underwent a course of "white graft rejection", which probably contributed to rejection.

Weighted learning of bidirectional associative memories by global minimization

A weighted learning algorithm for bidirectional associative memories (BAMs) by means of global minimization, where each desired pattern is weighted, is described. According to the cost function that measures the goodness of the BAM, the learning algorithm is formulated as a global minimization problem and solved by a gradient descent rule. The learning approach guarantees not only that each desired pattern is stored as a stable state, but also that the basin of attraction is constructed as large as possible around each desired pattern. The existence of the weights, the asymptotic stability of each desired pattern and its basin of attraction, and the convergence of the proposed learning algorithm are investigated in an analytic way. A large number of computer experiments are reported to demonstrate the efficiency of the learning rule.

[Comparative study of the transplantation of vascular pedicle and traditional free tendon tissues]

The most frequent cause of failure after tendon transplantation is the formation of adhesions between the tendon graft and its surrounding tissues. In this study, the healing mechanism, adhesion formation and biomechanical properties of vascular pedicle and traditional free tendon grafts were compared in the rabbits. It was observed that the former remained normal histologically in healing process and had less adhesion formation; that of the latter underwent necrosis and was gradually replaced by new connective tissues, its adhesions were extensive and dense; and that the healing mechanism of the both tendon grafts at the anastomosed site were extrinsic, the biomechanical properties (rupture load and elastic stiffness) showed no statistically significant difference (P greater than 0.05). On the basis of these results, we believe that preserving of the blood supply of tendon graft is important for reducing the adhesion formation and improving the functional results.