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Biomedical subjects

Q Dai

Publications and source records attributed to Q Dai.

At least 55 records · Page 3Linked to original sources
PubMed1999

Urinary excretion of isoflavonoids and the risk of breast cancer.

Isoflavonoids are a group of biologically active phytochemicals that humans are exposed to mainly through soy food intake. Because of the similar chemical structure of these compounds and estradiol, it has been hypothesized that isoflavonoids may be related to the risk of breast cancer. Overnight urine samples from 60 incident breast cancer cases and their individually matched controls were assayed for urinary excretion rates of five major isoflavonoids (daidzein, genistein, glycitein, equol, and O-desmethylangolensin) and total phenols. These subjects were from a large population-based case-control study conducted in Shanghai, and urine samples from breast cancer cases were collected before any cancer therapy to minimize the potential influence of the disease and its sequelae on study results. Urinary excretion of total phenols and all individual isoflavonoids, particularly glycitein, was substantially lower in breast cancer cases than controls. For total isoflavonoids, the mean excretion was 13.95 nmol/mg creatinine (SD, 20.76 nmol/mg creatinine) for cases and 19.52 nmol/mg creatinine (SD, 25.36 nmol/mg creatinine) for controls (P for difference = 0.04). The case-control difference was more evident when median levels of these compounds were compared, with the median excretion of all major isoflavonoids being 50-65% lower in cases than in controls. Individuals in the highest tertile of daidzein, glycitein, and total isoflavonoids had about half the cancer risk of those in the lowest tertile. The adjusted odds ratio for breast cancer was 0.14 (95% confidence interval, 0.02-0.88) for women whose urinary excretion of both phenol and total isoflavonoids was in the upper 50% compared with those in the lower 50%. The results from this study support the hypothesis that a high intake of soy foods may reduce the risk of breast cancer.

Adult↗
PubMed1998

Mammalian prenylcysteine carboxyl methyltransferase is in the endoplasmic reticulum.

Prenylcysteine carboxyl methyltransferase (pcCMT) is the third of three enzymes that posttranslationally modify C-terminal CAAX motifs and thereby target CAAX proteins to the plasma membrane. Here we report the molecular characterization and subcellular localization of the first mammalian (human myeloid) pcCMT. The deduced amino acid sequence of mammalian pcCMT predicts a multiple membrane-spanning protein with homologies to the yeast pcCMT, STE14, and the mammalian band 3 anion transporter. The human gene complemented a ste14 mutant. pcCMT mRNAs were ubiquitously expressed in human tissues. An anti-pcCMT antiserum detected a 33-kDa protein in myeloid cell membranes. Ectopically expressed recombinant pcCMT had enzymatic activity identical to that observed in neutrophil membranes. Mammalian pcCMT was not expressed at the plasma membrane but rather restricted to the endoplasmic reticulum. Thus, the final enzyme in the sequence that modifies CAAX motifs is located in membranes topologically removed from the CAAX protein target membrane.

Amino Acid Sequence↗
PubMed1998

[A pathological study on obliterative arteriopathy in human renal allografts].

OBJECTIVE: To observe the histopathological changes of obliterative arteriopathy (OBA) in human renal allografts, analyse OBA cellular components and probe its pathogenesis. METHODS: 74 renal allografts removed due to acute vascular rejection and chronic rejection were studied by light microscopy, electron microscopy and immunohistochemistry methods. RESULTS: OBA predominately affected the intima of interlobar, arcuate and interlobular arteries in all the 74 renal allografts. 29 cases developed OBA within 3 months post transplantation. 19 (25.7%) renal allografts showed early OBA with intimal arteritis, 55 (74.3%) cases had advanced OBA with intimal spindle-shaped smooth muscle cell (SMC) proliferation and intimal fibrosis. The cellular composition of OBA consisted of two origins, one from the host and the other from arterial wall intrinsic cells of renal allografts, including T lymphocytes; monocyte/macrophage cells; endothelial cells and different phenotypes--"contractile" or "synthetic" SMCs, "synthetic" SMCs secreted collagen types I, III. CONCLUSION: Our findings suggest that OBA is a post transplantation intrarenal arterial wall proliferative lesion. It is the result of a series of interactions between host immunocytes and allograft vascular wall cells. OBA is a type of immune reaction.

Graft Occlusion, Vascular↗
PubMed1998

[Ultrasonographic diagnosis of peritoneal mesothelioma].

OBJECTIVE: To investigate the sonographic features of peritoneal mesothelioma and its relationship with the gross pathology. METHODS: The ultrasonographic results of 14 cases with peritoneal mesothelioma were summarized, the sonographic features were compared with the gross pathology. RESULTS: With ultrasound examination a sheetlike mass was seen in two patients and a localized irregular mass was seen in one. Involvement of "cakelike omentum" was present in five. Pelvic mass was seen in eight and two were also with abdominal mass; one presented abdominal mass only. Bowel adhesion was found in one. Ascites was presented in all patients except one. CONCLUSIONS: It is possible for ultrasonography to suggest the diagnosis of peritoneal mesothelioma, when the sheetlike or irregular mass of peritoneum was founded. Ultrasound guided biopsy was helpful in diagnosis of peritoneal mesothelioma before operation.

Adult↗
PubMed1998

[CD44v and nm23-H1 gene product expression and its clinical significance in human recurrent bladder cancer].

OBJECTIVE: To investigate the expression of the CD44v and nm23-H1 gene products and its clinical significance in human recurrent bladder cancer. METHOD: The CD44v and nm23-H1 gene products in 45 cases of bladder cancer were analysed quantitatively by flow cytometry and cytoimmunofluorescence staining. RESULT: The CD44v gene product overexpression and nm23-H1 gene product low expression were correlated with invasive extent and recurrence of bladder cancer (P < 0.05). The correlation coefficients between CD44v gene product and nm23-H1 gene product were gamma = -0.2876 in bladder cancer. The correlation coefficients between CD44v gene product and nm23-H1 gene product were gamma = -0.4238 in recurrent bladder cancer. CONCLUSION: The expression of CD44v and nm23-H1 gene product cooperated in growth and progress of bladder cancer. Both CD44v and nm23-H1 gene products were an objective indication of invasive extent and recurrence of bladder cancer.

Adult↗
PubMed1997

Green tea consumption and the risk of pancreatic and colorectal cancers.

The effect of green tea drinking in reducing human cancer risk is unclear, though a protective effect has been reported in numerous animal studies and several epidemiologic investigations. Herein the hypothesis that green tea consumption may reduce the risk of cancers of the colon, rectum and pancreas is examined in a large population-based case-control study conducted in Shanghai, China. Newly diagnosed cancer cases (931 colon, 884 rectum and 451 pancreas) during 1990-1993 among residents 30-74 years of age were included. Controls (n = 1,552) were selected among Shanghai residents and frequency-matched to cases by gender and age. Multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of each cancer associated with green tea consumption were derived after adjustment for age, income, education and cigarette smoking. Additional adjustment for dietary items and body size was found to have minimal impact. An inverse association with each cancer was observed with increasing amount of green tea consumption, with the strongest trends for rectal and pancreatic cancers. For men, compared with non-regular tea drinkers, ORs among those in the highest tea consumption category (> or = 300 g/month) were 0.82 for colon cancer, 0.72 for rectal cancer and 0.63 for pancreatic cancer, with p values for trend being 0.38, 0.04 and 0.04, respectively. For women, the respective ORs for the highest consumption category (> or = 200 g/month) were 0.67, 0.57 and 0.53, with the respective p values for trend being 0.07, 0.001 and 0.008. Our findings provide further evidence that green tea drinking may lower the risk of colorectal and pancreatic cancers.

Adult↗
PubMed1997

Prior immunity-related medical conditions and oesophageal cancer risk: a population-based case-control study in Shanghai.

To investigate the role of immunity-related medical conditions in the aetiology of oesophageal cancer, data were analysed from a population-based case-control study, conducted in Shanghai during 1992-93. Information on histories of selected autoimmune diseases and allergic conditions was obtained from 163 incident cases of oesophageal cancer and 275 age- and sex-matched controls through personal interviews using a structured questionnaire. A significant 2.4-fold excess risk (95% CI, 1.3-4.4) of oesophageal cancer was associated with a history of autoimmune diseases after adjustment for age and sex. In contrast, a history of allergy was associated with a reduced risk (adjusted OR = 0.6, 95% CI = 0.4-0.9). The risk was also reduced 30-40% among individuals who reported having a moderate or strong skin reaction to mosquito bites. This study suggests that host immune function may be involved in the aetiology of oesophageal cancer. Further investigations into the mechanism of these observed associations are warranted.

Adult↗
PubMed1996

Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China.

To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990, and June 30, 1993. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.

Aged↗
PubMed1996

Endovascular embolization with self-made silk segment suspension in a rabbit model.

OBJECTIVE: To evaluate the efficacy and the histologic changes caused by self-made silk segment suspension as an agent for endovascular embolization of the external carotid artery of rabbit. METHODS: Three different silk suspension were used to perform selective endovascular embolization of the external carotid artery in 21 rabbits. Postembolization changes were investigated by angiography, light and electron microscopy, and behavioral and functional examination made in various groups of rabbits. RESULTS: The vascular changes in the group of simple silk segment were limited. The intima became thinner, while the media and adventitia were intact. However, in groups of ethanol-or estrogen-soaked silk segments, there was evident destruction of all layers of the vascular wall, including the intima, the media and the adventitia. CONCLUSIONS: Estrogen- or ethanol-soaked silk suspension is ideal and reliable for endovascular embolization, with the former being more effective than the latter. The obliteration caused by the suspension of simple silk segment was due to mechanical packing and compression plus incomplete thrombosis, which is likely to result in recurrence through compensatory collateral circulation.

Animals↗
PubMed1996

Endovascular embolization of intracranial aneurysms with self-made tungsten coils in a dog model.

OBJECTIVE: To evaluate the embolization effects and the long-term histologic changes, including the ultrastructure of the neoendothelium, in experimental canine aneurysms obliterated with self-made tungsten microcoil. METHODS: Twenty-eight experimental aneurysms were microsurgically created in 14 mongrel dogs by using end-to-side jungular carotid anastomosis. The aneurysms were obliterated with either self-made tungsten microcoil alone or the microcoil plus micro direct current electrocoagulation, with preservation of the parent vessel. The animals were kept in observation. 48 hours, 4 weeks, and 4 months after the embolization of the aneurysms, repeated carotid arteriography was performed to assess the potential recanalization of the aneurysms. The animals were then respectively killed and submitted for autopsy. The carotid artery and the embolized aneurysms were resected and studied with light and electron microscopy. RESULTS: A total of 14 obliterated aneurysms were completely excluded from the parent circulation by an endothelialized layer of connective tissue. The fundus of the aneurysm was completely obliterated by heavy reactive fibrous tissue surrounding the microcoils with very minimal inflammatory reaction. CONCLUSIONS: Tungsten microcoils are a relatively ideal embolic material at present for endovascular treatment of aneurysms. Microcoils plus micro direct current electrocoagulation yield more reliable, accurate, and safer embolic effects than microcoils alone for the obliteration of aneurysms.

Animals↗
PubMed1996

[Characterization of renal pelvic carcinoma with US and color Doppler flow imaging].

Ultrasonography (US) was utilized to assess 22 patients with renal pelvic carcinomas, The neoplasms were demonstrated as hypoechoic mass in 81.82%, and as visualized hyperechoic mass in 18.18%; Their echogenicity was highly correlated with gross pathology. Among all the cases, 5 patients were investigated with color Doppler Flow Imaging (CDFI), and none of them demonstrated the high-frequency Doppler shifted signals seen in renal cell carcinomas. Therefore CDFI may help to differentiate renal pelvic carcinomas from renal cell carcinomas.

Adult↗
PubMed1995

Prior immunity-related medical conditions and pancreatic-cancer risk in Shanghai.

To investigate the role of immunity-related medical conditions in the etiology of pancreatic cancer, we analyzed data from a population-based case-control study of pancreatic cancer conducted in Shanghai during 1992 and 1993. Information on prior histories of selected auto-immune diseases and allergic conditions was obtained from 108 incident pancreatic-cancer cases and 275 age- and gender-frequency matched controls by face-to-face interviews using a structured questionnaire. A prior history of auto-immune diseases was associated with a 2-fold elevated risk of pancreatic cancer (95% CI = 1.0-4.2), with an indication of a dose-response relation for the number of reported diseases. In contrast, a prior history of allergic condition was related to reduced risk (OR = 0.6, 95% CI = 0.4-1.1). With the possible exception of drug allergy, such an inverse association was seen for virtually all allergic conditions., although none of the OR was statistically significant. This study suggests that host immune function may be involved in the etiology of pancreatic cancer. Further investigations into the mechanism of these observed associations are warranted.

Adult↗
PubMed1995

Cigarette smoking and alcohol consumption and the risk of pancreatic cancer: a case-control study in Shanghai, China.

Cancer of the pancreas has been rising in incidence in Shanghai, China since the early 1970s. In 1987-89, this malignancy ranked eighth in cancer incidence among men and ninth among women in Shanghai. To examine risk factors for this tumor in urban Shanghai, a population-based case-control study was conducted. Cases (n = 451) were permanent residents of Shanghai, 30 to 74 years of age, newly diagnosed with pancreatic cancer between 1 October 1990 and 30 June 1993. Deceased cases (19 percent) were excluded from the study. Controls (n = 1,552) were selected among Shanghai residents, frequency-matched to cases by gender and age. Cases and controls were interviewed about their demographic background and potential risk factors, including tobacco, alcohol and beverage consumption, diet, and medical history. Adjusted odds ratios (OR) and 95 percent confidence intervals (CI) were estimated using logistic regression models. Current cigarette smoking was associated with excess risk of pancreatic cancer in both men (OR = 1.6, CI = 1.1-2.2) and women (OR = 1.4, CI = 0.9-2.4). ORs increased significantly with number of cigarettes smoked per day, and with duration and pack-years of smoking. Risk increased three- to sixfold among those in the highest categories of cigarette consumption, while risk decreased with increasing years since smoking cessation. Former smokers who stopped smoking for 10 or more years had risks comparable to nonsmokers.

Adult↗
PubMed1995

Percutaneous endovascular embolization of intracerebral arteriovenous malformations. Experience in 72 cases.

Endovascular therapeutic embolization of arteriovenous malformations (AVMs) of the brain was performed in 72 patients between October 1986 and March 1993. From October 1986 to May 1991, 38 patients in this series were treated with isobuty1-2-cyanoacrylate (IBCA) glue. After June 1991, in the remaining 34 patients the embolic materials used included surgical silk (5-0), polyvinyl alcohol (PVA), ethanol, and estrogen. After treatment, 29 patients (40.3%) had complete angiographic obliteration of AVM, 15 (21%) transient neurologic postembolization deficit, and 3 (4%) permanent deficit without death. Embolic agents and procedures are discussed as to their curative effects, safety, normal perfusion pressure breakthrough (NPPB) problem, with silk mixture fluid being considered preferable.

Adolescent↗
PubMed1995

Dietary factors and the risk of pancreatic cancer: a case-control study in Shanghai China.

In Shanghai, China, age-adjusted incidence rates for pancreatic cancer have increased steadily, beginning in the early 1970s. To examine the effects of diet on this cancer, a population-based case-control study was conduct. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990 and June 30, 1993. Decreased cases (19%) were excluded from the study. Controls (n = 1552) were selected among Shanghai residents, frequency matched to cases by gender and age. Information on usual adult dietary intake was obtained by trained interviewers in person, using a food frequency questionnaire. Dietary associations were measured by odds ratios and 95% confidence intervals. Risks of pancreatic cancer were inversely associated with consumption of vegetables (P for trend among men = 0.03; among women = 0.15) and fruits (P among men = 0.02; among women = 0.08). Reductions in risk were related also to intake of dietary fiber and micronutrients abundant in plant sources, such as vitamins C and E and carotene. There was also an inverse association with egg consumption (P for trend among men = 0.08; among women = 0.001). No consistent positive associations were observed with intake of other food groups, including preserved animal foods, fresh red meat, organ meat, poultry, and staple foods. On the other hand, risks increased with frequency of consumption of preserved vegetables and foods that were deep fried, grilled, cured, or smoked, providing clues to the possible role of nitrosamines, polycyclic aromatic hydrocarbons, and heterocyclic aromatic amines. The inverse associations observed with intake of dietary fat and protein in our study were unexpected, although these findings were based on consumptions well below the average intake in Western countries, where most previous studies on pancreatic cancer were conducted. Our results suggest that dietary variations have contributed little to the rising trends of pancreatic cancer in Shanghai. However, given the improving food availability and changing dietary patterns in China, further study of dietary and nutritional risk factors for pancreatic cancer appears warranted.

Adult↗
PubMed1994

Risk factors for esophageal cancer in Shanghai, China. I. Role of cigarette smoking and alcohol drinking.

A population-based case-control study of esophageal cancer was conducted in urban Shanghai involving interviews with 902 cases and 1,552 controls. Risk of esophageal cancer was increased among tobacco smokers and alcohol drinkers. Odds ratios (OR) for smoking were 2.1 and 1.6 for men and women, respectively, and increased with number of cigarettes smoked per day, duration of smoking, number of pack-years and decreasing age at start of smoking. For men who were current alcohol drinkers OR was 1.4, with the excess risk primarily among heavy drinkers. Few women drank alcoholic beverages. The combined effect of heavy smoking and drinking among men was pronounced: OR was 12.0 for those who smoked more than 1 pack per day and drank more than 750 g of ethanol per week. The relation with smoking appeared stronger for cancers of the middle and lower thirds of the esophagus than for the upper third, while patterns of risk for squamous cell carcinoma and adenocarcinoma were similar. Heavy drinking affected all 3 subsites, with increased risks mainly limited to squamous cell carcinoma. Cigarette smoking and alcohol drinking combined accounted for almost 50% of all esophageal cancers among men in Shanghai; among women, 14% of cases were attributed to smoking. Our study confirms that smoking and drinking are important risk factors for esophageal cancer in China, thereby paralleling findings from developed countries.

Adenocarcinoma↗
PubMed1994

Risk factors for esophageal cancer in Shanghai, China. II. Role of diet and nutrients.

A population-based case-control study of esophageal cancer (902 cases, 1,552 controls) in Shanghai, China, investigated the etiologic role of diet. After adjustment for cigarette smoking, alcohol consumption and other risk factors, increasing consumption of fruits, dark orange vegetables and beef or mutton was associated with statistically significant decreasing trends in risk for esophageal cancer. In general, risks were about 40% lower among those in the upper vs. lower quartiles of intake of these foods. Fivefold increases in risk were observed among those who consumed burning hot soup or porridge, with smaller excesses for preserved vegetables, salty and deep fried foods. Nutrient analysis revealed that increased dietary intake of protein, carotene, vitamins C and E and riboflavin was associated with reduced esophageal cancer risk. Our findings support the notion that the reported temporal increases in the per capita consumption of fruits, vegetables and animal products contribute to the substantial reduction in the incidence of esophageal cancer in Shanghai, particularly since cigarette and alcohol use has not decreased.

Adult↗