Family history and prostate cancer risk

The authors examined the relation between family history of prostate cancer and the risk of this cancer in a population-based case-control study conducted in Massachusetts between December 1992 and October 1994. Cases were all incident cases of prostate cancer in men younger than 70 years (n = 563); controls were men with no history of the disease matched to the cases on age and town of residence (n = 703). Prostate cancer risk was increased among men who reported a history of this cancer in either their fathers or brothers (odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.7-3.3). Risk varied with the number of relatives affected and their relationship to the case. For a history of prostate cancer in one relative, the OR was 2.2 (95% CI 1.5-3.2); if two or more relatives were affected, it was 3.9 (95% CI 1.7-5.2). For prostate cancer in the father, the OR was 1.9 (95% CI 1.2-3.0); for prostate cancer in a brother, it was 3.0 (95% CI 1.8-4.9). Risk was inversely related to the subject's age and to age at diagnosis of prostate cancer in his affected relative. Among probands younger than 60 years, the OR was 5.3 (95% CI 2.5-12); for those 60-64 years of age, the OR was 2.7 (95% CI 1.3-5.5); and for those 65 years of age and older, the OR was 1.6 (95% CI 1.0-2.5). For prostate cancer diagnosed in a relative before age 65, the OR was 4.1 (95% CI 2.3-7.3); for detection of the disease after age 74, the OR was 0.76 (95% CI 0.38-1.5). The association was present both among men with local and advanced stage disease and among men whose prostate cancer was detected either by screening or because of symptoms. These data provide evidence that after controlling for diet and other potential confounders, familial factors are significantly associated with the risk of prostate cancer.

A simple, rapid, reproducible tie-over dressing

A simple and quickly performed technique for the construction of tie-over dressings is described. After adjustment of the graft to the skin defect, skin staples are used to tack simultaneously the graft and looped silk threads circumferentially. Securing the threads is achieved by using a shortened disposable syringe cylinder through which the threads are passed and held in place by the adjusted piston. A stable fixation is easily achieved in all cases using one or more of these devices depending on the size of the defect. This technique enables the subsequent application of the dressing if needed.

Transdifferentiation of human islets to pancreatic ductal cells in collagen matrix culture

Transdifferentiation is a change from one differentiated phenotype to another, involving morphological and functional phenotypic markers. Stability of the cellular phenotype is probably related to the extracellular milieu, as well as cytoplasmic and nuclear components that interact to control gene expression, and the conversion of cell phenotype is likely to be accomplished by selective enhancement of gene expression, which controls the terminal developmental commitment of cells. In this paper, we show the induction of cultured human islets cells to alter their usual phenotypic expression and attain morphological and functional characteristics of duct cells. Islets were isolated by collagenase digestion of pancreata that were removed from cadaveric organ donors. The islets were purified on a two-step density gradient of bovine serum albumin and were then placed into a three-dimensional rat-tail collagen gel matrix supplemented with NuSerum epithelial growth factor and cholera toxin. During the initial 96 h of culture, the islets underwent a cystic transformation that was associated with (1) the maintenance of immunoreactivity for neuron-specific enolase, an endocrine cell marker, but a progressive loss of insulin gene expression, (2) a loss of immunoreactivity for insulin protein, and (3) the appearance of CK-19, a marker for ductal cells. After the transformation was complete, the cells had the ultrastructural appearance of primitive duct-like cells. Cyst enlargement after the initial 96 h was associated, at least in part, with cell replication, as reflected in the 1500% increase in the incorporation of tritiated thymidine. These experiments are consistent with the transdifferentiation of an islet cell to a ductal cell. The exact mechanisms involved still need to be fully elucidated.

Expression of endothelin-1 in pancreatic tissue of patients with chronic pancreatitis

Chronic pancreatitis is characterized by the presence of an inflammatory infiltrate, progressive destruction of acinar cells, and fibrosis. The finding that endothelin-1, an endothelium-derived peptide with vasoconstrictive and mitogenic properties, reduces pancreatic blood flow in normal rats suggested that the peptide may be associated with the reduced pancreatic flow seen in animal models of chronic pancreatitis and in the morphological abnormalities of the disease. The aim of this study was to investigate sites of endothelin-1 expression in the pancreas of normal subjects and patients with chronic pancreatitis. The techniques of immunohistochemistry, in situ hybridization, and Northern blotting were used. Endothelin-1-like immunoreactivity was localized predominantly to islet cells both in normal subjects and in patients with chronic pancreatitis. Semi-quantitative analyses of immunostaining showed that endothelin-1-like immunoreactivity in islet cells of patients with chronic pancreatitis was greater than in normal subjects. Co-localization studies with glucagon, insulin, somatostatin, and pancreatic polypeptide showed that endothelin-1-like immunoreactivity co-exists with glucagon and insulin. There was no apparent co-existence of endothelin-1-like immunoreactivity with somatostatin or pancreatic polypeptide. Endothelin-1 mRNA was expressed in sites similar to those of the immunostaining, as well as in vascular endothelial cells. Northern blot analysis showed an increase in the expression of endothelin-1 mRNA in the patient population. There was a significant correlation between intensity of endothelin-1 immunostaining and severity of fibrosis in the patients with chronic pancreatitis. These findings suggest that an elevation in local expression of endothelin-1 may be associated with the morphological and haemodynamic changes of chronic pancreatitis.

Decorin regulates collagenase gene expression in fibroblasts adhering to vitronectin

Vitronectin, a principal cell adhesion molecule in plasma and extracellular matrix, mediates cell adhesion and spreading via the alpha V family of integrins. In this study we demonstrate that decorin, a small dermatan sulfate proteoglycan, regulates extracellular matrix remodeling in rabbit synovial fibroblasts adhering to vitronectin. Decorin induced the expression of the matrix metalloproteinase collagenase (MMP-1) when present on the substrate with vitronectin, or with the 120-kDa cell-binding domain of fibronectin, but not when present with intact fibronectin or Type I collagen. Secreted collagenase was detected within 8 h of adhesion, there was no associated alteration in cell shape or focal contact formation in cells adhering to decorin plus vitronectin, whereas cell rounding was observed in cells adhering to decorin plus the 120-kDa fragment of fibronectin. The core protein of decorin, but not the glycosaminoglycan moiety, was sufficient to induce collagenase expression on both substrates; however, the glycosaminoglycan moiety of decorin as well as the core were required for cell rounding observed in cells adhering to the 120-kDa domain of fibronectin. The collagenase-inducing effect of decorin seems to be independent of its effects on transforming growth factor-beta, as function-blocking antibodies against transforming growth factor-beta did not interfere with the collagenase-inducing effects of decorin. These data indicate that decorin has specific gene regulatory effects in cells when present in the matrix with vitronectin or the 120-kDa fragment of fibronectin, polypeptides that are present in actively remodeling tissues. Thus, in combination, these adhesion regulatory molecules transduce novel signals that may contribute to the tissue remodeling process in morphogenesis, wound healing and disease states.

Alterations in pancreatic microcirculation and expression of endothelin-1 in a model of chronic pancreatitis

Chronic pancreatitis (CP) is characterized by the presence of an inflammatory infiltrate with progressive destruction of acinar cells and fibrosis. The finding that endothelin-1 (ET-1), an endothelium-derived peptide having vasoconstrictive and mitogenic properties, reduces pancreatic blood flow (PBF) in normal rats suggested that the peptide may be associated with the reduced PBF seen in animal models of CP and with the morphological abnormalities of the disease. This study investigates changes in blood flow to the pancreas and other abdominal organs in a rat model of CP and compares ET-1 production in the pancreata of these rats and normal controls. CP was induced in male Wistar rats by the injection of oleic acid into the common bile/pancreatic duct. The radiolabeled microsphere technique was employed to measure blood flow to the pancreas, duodenum, liver, spleen, and kidneys. Immunohistochemistry was used to investigate the cellular production of ET-1. After 3 weeks, significant decreases were noted in body weight, pancreatic weight, and pancreatic DNA, amylase, and protein content in the animals with CP. PBF was reduced by 64% and duodenal blood flow by 80% relative to those in control animals. Hepatic and splenic blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flows were increased by 91 and 88%, respectively, compared to those in controls. A 50% decrease in renal blood flow was also seen in the experimental group after 3 weeks. Pancreata from animals with CP stained diffusely for ET-1 in the cytoplasm of vascular endothelial, acinar, and ductal cells. In the control pancreata, focal staining for ET-1 was observed only in acinar cells. This difference was significant in endothelial and ductal cells. There was weak staining of islet cells in both groups. The results suggest that elevation in local production of ET-1 may be associated with the morphological and hemodynamic changes of CP.

Induction of islet cell differentiation and new islet formation in the hamster--further support for a ductular origin

Partial obstruction of the adult hamster pancreas leads to islet cell differentiation and new islet formation. From morphologic and morphometric observations, we have tentatively identified the source of the new islet tissue to be from cells in the ducts. In this study, in vivo labeling with a single pulse of tritiated thymidine after partial duct obstruction was used to ascertain whether newly formed islet cells were in fact derived from cells in the ductal epithelium. Supportive evidence for this formulation was also sought using immunocytochemistry for islet hormones and in situ hybridization for glucagon and insulin mRNA to probe areas of proliferating duct cells. Endocrine cell differentiation was observed as a migration of cells out from small ducts beginning at about 10 days after obstruction. Duct and islet cell labeling indices (LI;%) in control animals remained at a low level (0.25 +/- 0.01 and 0.26 +/- 0.03, respectively) throughout the experiment. In contrast, at 2 weeks after partial obstruction, the duct and islet cell LI were 4.2 +/- 0.7 and 0.80 +/- 0.1 (p < 0.05 vs. control). After 2 weeks, there was a rapid and significant 86% decline in the duct cell LI to a low of 0.6 +/- 0.2 at 8 weeks, which was accompanied by a comparable, but reciprocal, 113% increase in the islet cell LI to a high of 1.7 +/- 0.8 (p < 0.05). In situ hybridization demonstrated glucagon and insulin mRNA-positive cells within intralobular ducts as early as 6 and 8 days, respectively, after obstruction. Glucagon and insulin peptides appeared in these cells at approximately 8 and 10 days, respectively, as cells migrated out from the duct wall. This study provides additional evidence that further supports our concept that pancreatic endocrine cell differentiation in this model reiterates the normal ontogeny of beta cell differentiation from cells in the ductular epithelium.

Long-term culture and immortalization of epithelial cells from normal adult human pancreatic ducts transfected by the E6E7 gene of human papilloma virus 16

Pancreatic cancer is one of the most lethal cancers in humans. The majority of these cancers arise from the pancreatic duct epithelium. Research into the pathogenesis of pancreatic carcinoma has largely relied on animal models. In vitro models of pancreatic carcinogenesis using propagable cultured epithelial cells derived from the pancreatic ducts of rats and hamsters have been described. A human model, however, has been nonexistent due to the unavailability of propagable cultured duct epithelial cells derived from normal human pancreas. We report here a reproducible method for the long-term culture of pancreatic duct epithelial cells derived from normal and benign adult human pancreata by infection with a retrovirus containing the E6 and E7 genes of the human papilloma virus 16. One of these cell lines has become immortal and has propagated continuously for more than 20 passages. They remain anchorage dependent in their growth and nontumorigenic in nude mice. These cell lines and the methodology described here to establish them may provide new avenues for in vitro studies of the roles played by duct epithelium in human pancreatic diseases and cancers.

Adult height and risk of breast cancer among white women in a case-control study

Data from a hospital-based case-control study were analyzed to evaluate the relation of adult height to the risk of breast cancer among white women. The authors compared 5,358 newly diagnosed breast cancer cases and 4,555 controls interviewed from 1976 to 1992 in hospitals located mainly in the United States. Overall, there was no association between stature and risk of breast cancer. In comparison with women whose heights were less than 62 inches (< 158 cm), the adjusted odds ratios were 1.1 (95% confidence interval (Cl) 0.9-1.2), 1.0 (95% Cl 0.9-1.2), 1.0 (95% Cl 0.9-1.1), and 1.0 (95% Cl 0.8-1.2) for women with heights of 62-63, 64-65, 66-67, and > or = 68 inches (equivalent to 158-160, 163-165, 168-170, and > or =173 cm), respectively. There was no consistent evidence of modification of the effect of height by other risk factors. The results suggest that adult stature in white women is not related to the risk of breast cancer.

Islet-cell regeneration in the diabetic hamster pancreas with restoration of normoglycaemia can be induced by a local growth factor(s)

Partial pancreatic duct obstruction in the hamster leads to the induction of endocrine-cell differentiation and new islet formation. We prepared cytosolic extracts from the partially obstructed pancreas and identified one, which when administered i.p., produced significant increases in the incorporation of tritiated thymidine by ductular and islet cells, as well as a corresponding increase in islet mass. In this study, we evaluate the ability of this extract to reverse streptozotocin diabetes mellitus. Hamsters were treated i.p. twice daily for 7 weeks with either 0.9% NaCl (saline) (n = 10) or a cytosol extract (n = 10) prepared previously from partially obstructed hamster pancreata. All animals in the cytosol group survived vs only 60% of the saline group (p = 0.02). Random blood glucose levels were greater than 22.2 mmol/l in 90% of the saline group vs 40% in the cytosol group (p < 0.05). Pancreatic tissue from the surviving saline animals and from persistently hyperglycaemic cytosol-treated animals, showed intra-cytoplasmic vacuolation of islet cells, a characteristic lesion of sustained hyperglycaemic states. Vacuolation was not observed in normoglycaemic extract treated animals. Islets in hyperglycaemic animals demonstrated a profound decrease or absence of immunoreactive insulin, compared to an abundance of immunoreactive beta cells in cytosol-treated animals that reverted to normoglycaemia. In this group, single cells or nests of cells stained for insulin on glucagon cells were identified in ductal epithelium in association with cells budding from the duct. Morphometric analysis of pancreata in reverted cytosol-treated animals showed a new population of small islets compared with saline controls and an increased islet mass. In summary, streptozotocin diabetes can be reversed by new islet formation induced by local pancreatic growth factors, the exact nature of which remains to be determined.

Paracrine/autocrine regulation of pancreatic islet cell proliferation and differentiation in the hamster: studies using parabiosis

Partial obstruction of the pancreatic duct in hamsters leads to new islet formation and reversal of streptozotocin diabetes. The purpose of this study was to delineate the mechanism by which endocrine cell proliferation and differentiation is mediated in this model. Six pairs of parabiotic hamsters were established and partial duct obstruction was inducted in 1 parabiont from each pair. At 6 weeks, the pancreatic weight (mg/100g bw); DNA (microgram/100g bw) and protein content (mg/100g bw) showed 28% (167 +/- 21 vs. 130 +/- 17), 32% (1,052 +/- 206 vs. 795 +/- 159), and 20% (25.4 +/- 6.6 vs. 21.2 +/- 1.9) increases (p < 0.05), respectively, over the non-wrapped parabionts. Morphometric analysis demonstrated the presence of new islets in the wrapped pancreata with a 100% increase in the number of islets/mm2 compared with non-wrapped controls (0.90 +/- 0.5 vs. 1.8 +/- 0.7, p < 0.01). A cytosol extract was prepared from duct-obstructed pancreases, and 4 microliters/g bw injected i.p. twice daily for 2 d produced significant increases in pancreatic weight and DNA content of 12% and 40%, respectively. Cytosol extract from non-wrapped pancreata had no effects compared with saline. When wrapped cytosol extract was injected for 21 d, the labeling index of ductular and islet cells (% cell nuclei labeled with 3H-TdR) was increased 10- and 6-fold respectively over controls (2.42 +/- 0.28 vs. 0.23 +/- 0.01 and 1.17 +/- 0.01 vs. 0.25 +/- 0.04, respectively, p < 0.01). The trophic effects observed in this model of islet cell proliferation and differentiation did not appear to be mediated by a humoral mechanism because the changes induced by partial obstruction were not observed in the non-operated parabiont. Control of pancreatic endocrine cell growth in this model appears to involve paracrine and/or autocrine regulatory mechanisms.

Identification of differentially expressed genes induced in pancreatic islet neogenesis

Cellophane wrapping of the hamster pancreas induces islet neogenesis. We have used the mRNA differential display technique to select for genes expressed during islet neogenesis but not in control pancreata. Ten candidate clones have been identified. Upon sequencing, 6 clones showed a high degree of homology to known genes, 1 showed some, and 3 showed no homology to genes of known sequence. Thus, mRNA differential display is a useful technique to identify genes induced during islet neogenesis, and in combination with screening hamster pancreatic cDNA libraries for full length clones, will enhance the likelihood of capturing the participants in this process.

Case-control study of oral contraceptive use and risk of breast cancer

The relation of oral contraceptive use to the risk of breast cancer in white women aged 25-59 years was assessed with data collected during 1977-1992 in a case-control surveillance system in hospitals in Boston, New York, and Philadelphia. A total of 3,540 cases with breast cancer were compared with 4,488 controls with nonmalignant nongynecologic conditions unrelated to oral contraceptive use. Relative risk estimates were obtained by unconditional logistic regression with control for major risk factors. For at least 1 year of use relative to less than 1 year, the multivariate relative risk estimate was 1.7 (95% confidence interval (CI) 1.3-2.3) in women aged 25-34 years, 0.9 (95% CI 0.7-1.0) in women aged 35-44 years, and 1.2 (95% CI 1.0-1.4) in women aged 45-59 years (p < 0.01 for the difference across age). Among women aged 25-34 years, the relative risk estimates were greatest for use of long duration, but the trend was not statistically significant (p = 0.17); in addition, the duration of use was correlated with the recency of use, and it was not possible to distinguish their effects. Among women aged 35-44 years, the relative risk estimate decreased with increasing duration of use (p = 0.01). Among women aged 45-59 years, some relative risk estimates were increased, but there was no consistent pattern. The results add to the evidence of an association between oral contraceptive use and an increased risk of breast cancer at young ages.

Expression of endothelin-1 in pancreatic tissue of patients with chronic pancreatitis

Chronic pancreatitis is characterized by the presence of an inflammatory infiltrate, progressive destruction of acinar cells, and fibrosis. The finding that endothelin-1, an endothelium-derived peptide with vasoconstrictive and mitogenic properties, reduces pancreatic blood flow in normal rats suggested that the peptide may be associated with the reduced pancreatic flow seen in animal models of chronic pancreatitis and in the morphological abnormalities of the disease. The aim of this study was to investigate sites of endothelin-1 expression in the pancreas of normal subjects and patients with chronic pancreatitis. The techniques of immunohistochemistry, in situ hybridization, and Northern blotting were used. Endothelin-1-like immunoreactivity was localized predominantly to islet cells both in normal subjects and in patients with chronic pancreatitis. Semi-quantitative analyses of immunostaining showed that endothelin-1-like immunoreactivity in islet cells of patients with chronic pancreatitis was greater than in normal subjects. Co-localization studies with glucagon, insulin, somatostatin, and pancreatic polypeptide showed that endothelin-1-like immunoreactivity co-exists with glucagon and insulin. There was no apparent co-existence of endothelin-1-like immunoreactivity with somatostatin or pancreatic polypeptide. Endothelin-1 mRNA was expressed in sites similar to those of the immunostaining, as well as in vascular endothelial cells. Northern blot analysis showed an increase in the expression of endothelin-1 mRNA in the patient population. There was a significant correlation between intensity of endothelin-1 immunostaining and severity of fibrosis in the patients with chronic pancreatitis. These findings suggest that an elevation in local expression of endothelin-1 may be associated with the morphological and haemodynamic changes of chronic pancreatitis.

Expression of Reg gene in the Syrian golden hamster pancreatic islet regeneration model

We have reported previously that cellophane wrapping of the hamster pancreas is a stimulus that leads to the induction of duct epithelial cell proliferation, followed by endocrine cell differentiation and new islet formation. Reg is a candidate gene that has been reported to be expressed in regenerating pancreatic islets, suggesting a role in islet growth. We examined Reg gene expression in the cellophane-wrap model by isolating total RNA from hamster pancreata at various times after wrapping. Northern blot analysis using a rat cDNA Reg probe showed no expression of Reg in control non-wrapped hamster pancreas, whereas a strong signal was detected in control wrapped rat pancreas. Using reverse transcription of RNA followed by polymerase chain reaction (PCR) we amplified, isolated and sequenced a 194 base pair product which showed homology to rat Reg in both control and wrapped hamster pancreas. When the PCR product was used as a probe for Northern blot analysis, no signal was detected in control non-wrapped pancreata. In contrast, a strong signal was detected 1 and 2 days after wrapping, which then returned to basal between 4 and 6 days after wrapping. A similar temporal pattern was observed using in situ hybridization to localize the Reg gene. One- and 2-day wrapped but not control pancreas expressed Reg in acinar cells, but not in islets.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo cell transformation: neogenesis of beta cells from pancreatic ductal cells

During embryogenesis, islet cells differentiate from primitive duct-like cells. This process leads to the formation of islets in the mesenchyme adjacent to the ducts. In the postnatal period, any further expansion of the pancreatic endocrine cell mass will manifest itself either by a limited proliferation of the existing islet cells, or by a reiteration of ontogenetic development. It is the latter, cell transformation by a process of differentiation from a multipotential cell, that will be referred to in this review as islet neogenesis. To better appreciate the mechanisms underlying islet cell neogenesis, some of the basic concepts of developmental biology will be reviewed. Considerable discussion is devoted to the subject of transdifferentiation, a change in a cell or in its progeny from one differentiated phenotype to another, where the change includes both morphological and functional phenotypic markers. While in vitro studies with fetal and neonatal pancreata strongly suggest that new islet tissue is derived from ductal epithelium, what is not established is whether the primary cell is a committed endocrine cell or duct-like cell capable of transdifferentiation. Next, research in the field of beta-cell neogenesis is surveyed, in preparation for the examination of whether there is a physiological means of inducing islet cell regeneration, and whether the new islet mass will function in a regulated manner to reverse or stabilize a diabetic state? Our belief is that the pancreas retains the ability to regenerate a functioning islet cell mass in the postnatal period, and that the process of cell transformation leading to islet neogenesis is mediated by growth factors that are intrinsic to the gland. Furthermore, it is our contention that these factors act directly or indirectly on a multipotential cell, probably associated with the ductular epithelium, to induce endocrine cell differentiation. In other words, new islet formation in the postnatal period reiterates the normal ontogeny of islet cell development. These ideas will be fully developed in a discussion of the Partial Duct Obstruction (PDO) Model.

Oral contraceptive use and breast cancer risk among African-American women

Recent epidemiologic studies, most of them in predominantly White populations, have suggested that long duration of oral contraceptive (OC) use may increase the risk of breast cancer at young ages. We assessed the relationship of OC use to the risk of breast cancer in African-American women aged 25 to 59 years, using interview data from a multipurpose hospital-based case-control study. Five hundred and twenty-four cases hospitalized for invasive breast cancer were compared with 1,021 controls with nonmalignant conditions unrelated to OC use. Relative risks (RR) and 95 percent confidence intervals (CI) were estimated relative to a reference category of use for less than 12 months; potential confounders were controlled by multiple logistic regression analysis. Among women under age 45, three or more years of OC use was associated with an increased risk of breast cancer: the RR estimate was 2.8 (CI = 1.5-5.0) for three to four years of use, and declined to 1.5 (CI = 08.3.0) for 10 or more years of use. Recency and timing of use did not explain the observed association. Among women aged 45 to 59, OC use was associated with little or no increase in risk: the RR estimate for three or more years of use was 1.3 (CI = 0.7-2.4). The findings add to the evidence from studies of White women and a recent study of Black women which have suggested an increased risk of breast cancer at young ages for moderate or long duration use of OCs.

In Vivo Cell Transformation: Neogenesis of Beta Cells from Pancreatic Ductal Cells

During embryogenesis, islet cells differentiate from primitive duct-like cells. This process leads to the formation of islets in the mesenchyme adjacent to the ducts. In the postnatal period, any further expansion of the pancreatic endocrine cell mass will manifest itself either by a limited proliferation of the existing islet cells, or by a reiteration of ontogenetic development. It is the latter, cell transformation by a process of differentiation from a multipotential cell, that will be referred to in this review as islet neogenesis. To better appreciate the mechanisms underlying islet cell neogenesis, some of the basic concepts of developmental biology will be reviewed. Considerable discussion is devoted to the subject of transdifferentiation, a change in a cell or in its progeny from one differentiated phenotype to another, where the change includes both morphological and functional phenotypic markers. While in vitro studies with fetal and neonatal pancreata strongly suggest that new islet tissue is derived from ductal epithelium, what is not established is whether the primary cell is a committed endocrine cell or duct-like cell capable of transdifferentiation. Next, research in the field of β-cell neogenesis is surveyed, in preparation for the examination of whether there is a physiological means of inducing islet cell regeneration, and whether the new islet mass will function in a regulated manner to reverse or stabilize a diabetic state? Our belief is that the pancreas retains the ability to regenerate a functioning islet cell mass in the postnatal period, and that the process of cell transformation leading to islet neogenesis is mediated by growth factors that are intrinsic to the gland. Furthermore, it is our contention that these factors act directly or indirectly on a multipotential cell, probably associated with the ductular epithelium, to induce endocrine cell differentiation. In other words, new islet formation in the postnatal period reiterates the normal ontogeny of islet cell development. These ideas will be fully developed in a discussion of the Partial Duct Obstruction (PDO) Model.

Relation of benzodiazepine use to the risk of selected cancers: breast, large bowel, malignant melanoma, lung, endometrium, ovary, non-Hodgkin's lymphoma, testis, Hodgkin's disease, thyroid, and liver

Some animal data have raised the possibility that benzodiazepines influence the risk of selected cancers. With data collected in 1977-1991 in a US hospital-based study, the authors assessed the relation of benzodiazepine use to the risk of 11 cancers: breast (6,056 patients), large bowel (2,203), malignant melanoma (1,457), lung (1,365), endometrium (812), ovary (767), non-Hodgkin's lymphoma (382), testis (314), Hodgkin's disease (299), thyroid (111), and liver (37). Cases were compared with cancer controls (3,777 patients with other cancers) and noncancer controls (1,919 patients admitted for acute nonmalignant disorders). Relative risks were estimated for benzodiazepine use at least 4 days a week for at least 1 month, initiated at least 2 years before admission (sustained use) by multiple logistic regression with control for confounding factors. Results derived with noncancer controls were similar to those derived with cancer controls. For sustained benzodiazepine use relative to no use, relative risk estimates for all 11 cancers were compatible with 1.0 at the 0.05 level of significance. Relative risk estimates for durations of at least 5 years were also compatible with 1.0, with the exceptions of an increased estimate, of borderline statistical significance, for endometrial cancer, and a decreased estimate for ovarian cancer. Relative risk estimates both for sustained use that continued into the 2-year period before admission and for sustained use that ended up to > or = 10 years previously were compatible with 1.0, suggesting a lack of tumor promotion and no increase in the risk after a latent interval. Results were also null for diazepam, chlordiazepoxide, and other benzodiazepines considered separately. The results suggest absence of association between benzodiazepine use and the cancers considered, with the evidence stronger for the cancers with larger numbers of subjects. The similarity of results derived with cancer and noncancer controls suggests that benzodiazepines do not influence the risk of cancer as a whole.

Adult height and risk of breast cancer among US black women

Adult height has been positively associated with the risk of breast cancer in a number of recent investigations. The authors assessed height in relation to breast cancer risk in a case-control study of US black women aged 25-69 years; 674 hospital patients with newly diagnosed breast cancer and 1,155 controls hospitalized for nonmalignant conditions unrelated to height were interviewed. After control for multiple confounders, the relative risk estimate for women < 61 inches (< 154.9 cm) tall was 0.5 (95% confidence interval (Cl) 0.3-0.7) relative to the median height of 64-65 inches (162.6-165.1 cm). Among women > or = 61 inches (> or = 154.9 cm) tall, there was little indication of any variation in risk with increasing height. The findings suggest that short stature is associated with a decreased risk of breast cancer in US black women.

Coffee consumption and myocardial infarction in women

Whether coffee consumption increases the risk of coronary heart disease has not yet been established. In a case-control study of nonfatal myocardial infarction among Massachusetts women aged 45-69 years in 1986-1990, 858 cases with first infarctions were compared with 858 community controls matched on age and town precinct. Detailed information on coffee drinking, cigarette smoking, and other factors was obtained by telephone interview. Relative risks (as estimated by odds ratios) and their 95% confidence intervals were computed from multiple logistic regression analyses that controlled for smoking and other risk factors. The risk of myocardial infarction increased with increasing number of cups per day among both drinkers of any type of coffee and drinkers of caffeine-containing coffee only: tests for trend, p = 0.002 and p = 0.0004, respectively. For consumption of caffeine-containing coffee alone, the relative risk estimates for 5-6 cups, 7-9 cups, and 10 or more cups per day relative to less than 1 cup per day were 1.4 (95% confidence interval (CI) 0.8-2.5), 2.1 (95% CI 0.9-4.9), and 2.5 (95% CI 1.0-6.5), respectively. No increase was observed for fewer than 5 cups per day. The positive association with heavy coffee drinking was present among nonsmokers as well as smokers. These findings and other recent studies suggest that heavy coffee consumption increases the risk of myocardial infarction.

Parental ages at birth in relation to a daughter's risk of breast cancer among female participants in the Framingham Study (United States)

Data from the Framingham Heart Study, collected in Framingham, MA (United States) during 1948-86, were used to evaluate the relation of parental age at birth to the risk of breast cancer among daughters. After 38 years of follow-up, 149 breast cancer cases occurred among 2,662 women. All but two cases were confirmed by histologic report. The rate of breast cancer increased among daughters with increasing maternal age at birth up to the mid-30s, where the rate levelled off. A similar pattern was observed with paternal age. After adjustment for other confounding factors and paternal age, the rate ratios for breast cancer in daughters whose mothers were aged 26 to 31 years and 32 or more years at their birth, relative to women whose mothers were aged 25 years or younger, were 1.5 (95 percent confidence interval [CI] = 1.0-2.4) and 1.3 (CI = 0.8-2.2), respectively. However, there was no longer an association between paternal age at birth and risk of breast cancer after controlling for maternal age and other risk factors.

Low dose octreotide and tamoxifen in the treatment of adenocarcinoma of the pancreas

BACKGROUND

Data from experimental studies suggest that a combination of octreotide, the long acting somatostatin analogue, octreotide, and tamoxifen improves the survival of animals with pancreatic cancer.

METHODS

Twelve patients with a tissue diagnosis of ductal adenocarcinoma of the pancreas were treated with 100 micrograms of octreotide three times per day and tamoxifen 10 mg twice daily. The survival of the octreotide-tamoxifen group was compared with a historic cohort of 68 untreated patients with pancreatic cancer, matched for age, sex, and TNM stage.

RESULTS

The median survival times for the octreotide-tamoxifen-treated group compared with the historic cohort were 12 and 3, months respectively. Actuarial one-year survival rates for the octreotide-tamoxifen-treated group compared with the historic cohort were 59% and 16%, respectively.

CONCLUSIONS

In this study, patients with unresectable and resected ductal adenocarcinoma of the pancreas had an apparently increased survival when treated with a combination of octreotide and tamoxifen. A randomized controlled trial to examine this potential therapeutic benefit is now indicated.

The role of age and an expanded Health Belief Model in predicting skin cancer protective behavior

Skin cancer (SC), the most common form of cancer in the US, with a rapidly growing incidence, has become a target for health education. Sun exposure protective behavior (SEPB) is currently believed to be the best means to prevent it. Focusing on age differences, this paper applies an expansion of the Health Belief Model (HBM) to the prediction of engagement in SC protective behaviors in four age-groups, following an intervention program. It is based on data collected by a structured questionnaire completed by 509 members of four kibbutzim in Israel. The results indicate that the proposed model explains the SC-related protective behaviors of the older age-groups (45+) much better than that of the younger groups (15-44). The older age-groups are also more likely to change risky behavior following the intervention. The youngest age-group (15-29), although being highest at risk for SC due to sun exposure habits, is least likely to change them and least likely to participate in the intervention. Beliefs about sun tanning, sun exposure habits (barriers) and degree of exposure to the intervention are the best predictors of the likelihood to engage in SEPB in the younger age-groups, while among the older groups the best predictors are the value of health and appearance. These findings suggest that health education programs should develop different messages for different age-groups. Regarding SC, it seems especially important to focus prevention efforts on adolescents and young adults by recruiting the beauty and fashion industries as well as legislation. The merits of age group analyses in the research of health behavior are discussed.

Cyclosporine A blockade of the induction of ornithine decarboxylase activity as a cause of failure of islet cell proliferation and differentiation

Maintenance of islet cell mass may be one factor that contributes to long-term islet allograft viability. It is important, therefore, to determine whether transplant-related events, such as immunosuppression, interfere with the regenerative capacity of the hormone-producing cellular elements of the islet. To investigate this possibility, we utilized a well-characterized model of islet cell growth in which partial obstruction of the hamster pancreatic duct leads to the induction of duct epithelial cell proliferation in association with endocrine cell differentiation and new islet formation. These changes appear to be mediated by a specific trophic activity (TA) that can be extracted from the pancreas following obstruction. Since the trophic effects of many growth factors are mediated through the polyamine pathway, we postulated that the trophic effect of TA is associated with the induction of ornithine decarboxylase (ODC) activity, the rate-limiting step in polyamine biosynthesis. The effect of TA on pancreatic ODC activity was studied alone, and after pretreatment with cyclosporine A (CsA), an immunosuppressive agent that is known to inhibit ODC activity. Eight h following the administration of TA, pancreatic ODC activity increased approximately 6-fold. Pretreatment with CsA for 7 d at a daily dose of 20 mg/kg prevented the induction of pancreatic ODC activity. We conclude that, in this model, CsA can block islet cell proliferation, and that this may be mediated by inhibition of TA-stimulated ODC activity.

The self-association of biglycan from bovine articular cartilage

Biglycan is a small dermatan sulfate proteoglycan present in the extracellular matrix of a variety of connective tissues. Sedimentation velocity and equilibrium studies were carried out to determine the monomer molecular weight of biglycan in denaturing solvents and to define the oligomeric states of biglycan in physiologic solvents in the presence and absence of Zn2+. In 6 M guanidine chloride, biglycan is a monomer with s0(20,w) = 2.9 S and Mz = 93,100 (where Mz is z-average molecular weight). In 0.15 M NaCl, 50 mM Tris, pH 7.5, in the absence of divalent metal ions, and at concentrations above 1 mg/ml, biglycan is predominantly dimer (s0(20,w) = 4.8 S). Under these same conditions in solvent containing 5 mM Zn2+, biglycan exists predominantly as a hexamer, with s0(20,w) = 9.4 S and Mz approximately 600,000. In either case, the oligomers dissociate reversibly. In order to determine whether the glycosaminoglycan chains or the core protein was responsible for self-association, sedimentation velocity and sedimentation equilibrium studies were conducted on the isolated components. Dermatan sulfate chains prepared from biglycan, examined in both denaturing and physiologic solvents, show no significant difference in molecular weight (Mz approximately 22,000), whether or not the solvents contain Zn2+. However, biglycan core protein strongly self-associated in physiologic solvents. Thus, the self-association of biglycan appears to be mediated by the core protein and not by its glycosaminoglycan chains.

The relation of vasectomy to the risk of cancer

We previously reported a strong positive association between vasectomy and the risk of prostatic cancer that arose in multiple comparisons made within data collected from 1976 to 1988 in an ongoing hospital-based surveillance study of many exposures and diseases. We have reassessed this association with data collected in the surveillance study during 1988-1992 from a new set of patients (355 cases of prostatic cancer and 2,048 controls with nonmalignant conditions). Because some studies have reported increased relative risks of lung cancer and testicular cancer in vasectomized men, we also used the surveillance database (4,126 men with various cancers, 7,027 men with nonmalignant conditions) to assess the relation of vasectomy to the risk of these and other cancers. In the newly collected data, the multivariate relative risk estimate for prostatic cancer in vasectomized men was 1.2 (95% confidence interval (CI) 0.6-2.7). For lung cancer and testicular cancer, the relative risk estimates were 1.3 (95% CI 0.8-2.1) and 0.8 (95% CI 0.4-1.9), respectively; for lung cancer occurring > or = 15 years after vasectomy, the relative risk estimate was 1.9 but it was not statistically significant (95% CI 0.7-5.0). For pancreatic cancer, the relative risk estimate was 1.8 (95% CI 1.0-3.1). For each of the other cancers considered--malignant melanoma, large bowel cancer, bladder cancer, kidney cancer, lymphoma, leukemia, and other cancers--the relative risk estimate was 1.3 or less and compatible with a value of 1.0. The present data provide little support for an association of vasectomy with the risk of prostatic cancer or other cancers. In addition, the data from two sets of cases of prostatic cancer and controls interviewed consecutively illustrate that increased relative risks detected in screening for statistically significant associations may tend to have an upward bias and to be lower in subsequent data.