Inducible targeting of IL-13 to the adult lung causes matrix metalloproteinase- and cathepsin-dependent emphysema

Cigarette smoke exposure is the major cause of chronic obstructive pulmonary disease (COPD). However, only a minority of smokers develop significant COPD, and patients with asthma or asthma-like airway hyperresponsiveness or eosinophilia experience accelerated loss of lung function after cigarette smoke exposure. Pulmonary inflammation is a characteristic feature of lungs from patients with COPD. Surprisingly, the mediators of this inflammation and their contributions to the pathogenesis and varied natural history of COPD are not well defined. Here we show that IL-13, a critical cytokine in asthma, causes emphysema with enhanced lung volumes and compliance, mucus metaplasia, and inflammation, when inducibly overexpressed in the adult murine lung. MMP-2, -9, -12, -13, and -14 and cathepsins B, S, L, H, and K were induced by IL-13 in this setting. In addition, treatment with MMP or cysteine proteinase antagonists significantly decreased the emphysema and inflammation, but not the mucus in these animals. These studies demonstrate that IL-13 is a potent stimulator of MMP and cathepsin-based proteolytic pathways in the lung. They also demonstrate that IL-13 causes emphysema via a MMP- and cathepsin-dependent mechanism(s) and highlight common mechanisms that may underlie COPD and asthma.

Insulin independence in a type 1 diabetic patient after encapsulated islet transplantation

Identification of a biocompatible immunoprotective membrane to prevent graft rejection remained elusive until the development of microcapsules formulated in alginate high in guluronic acid. We report insulin independence in a type 1 diabetic patient after encapsulated islet transplantation. Encapsulated human islets were injected intraperitoneally in a diabetic patient with a functioning kidney graft. Insulin independence with tight glycaemic control was demonstrated 9 months after the procedure. These results warrant a trial of a high dose of encapsulated islets in early-onset diabetic patients.

Vascular endothelial growth factor (VEGF) is an autocrine growth factor for VEGF receptor-positive human tumors

Angiogenesis is required for the progression of tumors from a benign to a malignant phenotype and for metastasis. Malignant tumor cells secrete factors such as vascular endothelial growth factor (VEGF), which bind to their cognate receptors on endothelial cells to induce angiogenesis. Here it is shown that several tumor types express VEGF receptors (VEGFRs) and that inhibition of VEGF (VEGF antisense oligonucleotide AS-3) or VEGFRs (neutralizing antibodies) inhibited the proliferation of these cell lines in vitro. Furthermore, this effect was abrogated by exogenous VEGF. Thus, VEGF is an autocrine growth factor for tumor cell lines that express VEGFRs. A modified form of VEGF AS-3 (AS-3m), in which flanking 4 nucleotides were substituted with 2-O-methylnucleosides (mixed backbone oligonucleotides), retained specificity and was active when given orally or systemically in vitro and in murine tumor models. In VEGFR-2-expressing tumors, VEGF inhibition may have dual functions: direct inhibition of tumor cell growth and inhibition of angiogenesis.

Vascular endothelial growth factor/vascular permeability factor is an autocrine growth factor for AIDS-Kaposi sarcoma

Kaposi sarcoma (KS) is the most common tumor associated with HIV-1 infection and develops in nearly 30% of cases. The principal features of this tumor are abnormal vascularization and the proliferation of endothelial cells and spindle (tumor) cells. KS-derived spindle cells induce vascular lesions and display enhanced vascular permeability when inoculated subcutaneously in the nude mouse. This finding suggests that angiogenesis and capillary permeability play a central role in the development and progression of KS. In this study, we show that AIDS-KS cell lines express higher levels of vascular endothelial growth factor/vascular permeability factor (VEGF/VGF) than either human umbilical vein endothelial cells or human aortic smooth muscle cells. AIDS-KS cells and primary tumor tissues also expressed high levels of Flt-1 and KDR, the receptors for VEGF, while the normal skin of the same patients did not show any expression. We further demonstrate that VEGF antisense oligonucleotides AS-1 and AS-3 specifically block VEGF mRNA and protein production and inhibit KS cell growth in a dose-dependent manner. Furthermore, growth of KS cells in nude mice was specifically inhibited by VEGF antisense oligonucleotides. These results show that VEGF is an autocrine growth factor for AIDS-KS cells. To our knowledge, this is the first report that shows that VEGF acts as a growth stimulator in a human tumor. Inhibitors of VEGF or its cognate receptors may thus be candidates for therapeutic intervention.

Long-term reversal of diabetes by the injection of immunoprotected islets

The intraperitoneal injection of insulin-producing islets immunoprotected by an alginate-poly(amino acid) membrane is a potential method of reversing diabetes without the need for lifelong immunosuppression. Previous attempts to demonstrate this technology in large animals have failed, preventing application in humans. We have determined that key factors responsible for these past failures include cytokine (interleukins 1 and 6 and tumor necrosis factor) stimulation by mannuronic acid monomers from alginate capsules with weak mechanical integrity, which results in fibroblast proliferation. With this insight, we formulated mechanically stable microcapsules by using alginate high in guluronic acid content and report prolonged reversal of diabetes in the spontaneous diabetic dog model by the intraperitoneal injection of encapsulated canine islet allografts. Euglycemia, independent of any exogenous insulin requirement, was noted for up to 172 days. Graft survival, evidenced by positive C-peptide release, was noted for as long as 726 days in a recipient receiving a single injection of immunoprotected islets. Histological evidence of viable islets retrieved from the peritoneal cavity 6 months posttransplant confirmed the biocompatibility and immunoprotective nature of this capsule formulation. The finding that intraperitoneal injection of alginate-immunoprotected islets, a minimally invasive surgical procedure, is effective in prolonged (> 1 year) maintenance of glycemic control, without the need for lifelong immunosuppression, may have significant implications for the future therapy of type I diabetes in humans.

Targeted expression of IL-11 in the murine airway causes lymphocytic inflammation, bronchial remodeling, and airways obstruction

Interleukin-11 is a pleotropic cytokine produced by lung stromal cells in response to respiratory viruses, cytokines, and histamine. To further define its potential effector functions, the Clara cell 10-kD protein promoter was used to express IL-11 and the airways of the resulting transgene mice were characterized. In contrast to transgene (-) littermates, the airways of IL-11 transgene (+) animals manifest nodular peribronchiolar mononuclear cell infiltrates and impressive airways remodeling with subepithelial fibrosis. The inflammatory foci contained large numbers of B220(+) and MHC Class II(+) cells and lesser numbers of CD3(+), CD4(+), and CD8(+) cells. The fibrotic response contained increased amounts of types III and I collagen, increased numbers of alpha smooth muscle actin and desmin-containing cells and a spectrum of stromal elements including fibroblasts, myofibroblasts, and smooth muscle cells. Physiologic evaluation also demonstrated that 2-mo-old transgene (+) mice had increased airways resistance and non-specific airways hyperresponsiveness to methacholine when compared with their transgene (-) littermates. These studies demonstrate that the targeted expression of IL-11 in the mouse airway causes a B and T cell-predominant inflammatory response, airway remodeling with increased types III and I collagen, the local accumulation of fibroblasts, myofibroblasts, and myocytes, and obstructive physiologic dysregulation. IL-11 may play an important role in the inflammatory and fibrotic responses in viral and/or nonviral human airway disorders.

The far upstream element-binding proteins comprise an ancient family of single-strand DNA-binding transactivators

The cloning and expression of two new human cDNAs encoding proteins highly related to the far upstream element-binding protein (FBP) are described. FBP, FBP2, and FBP3 comprise a family of single-strand DNA- binding proteins that possess all of the general features of more conventional transcription factors. The FBPs each bind sequence specifically to only one strand of the far upstream element (FUSE; originally identified upstream of c-myc), and each possesses potent activation domains when fused to the GAL4 DNA-binding domain and assayed by transient transfection. Typical of transcription factors, the proteins are most highly related in their central, DNA-binding domains, but extensive homology is also shared within the tyrosine-rich, carboxyl-terminal activation domains. Comparison with GenBank sequences revealed a fourth FBP family member encoded by Caenorhabditis elegans chromosome III, illustrating the high degree of homology in this evolutionarily ancient and conserved family.

Corticostriatal combinatorics: the implications of corticostriatal axonal arborizations

The complete striatal axonal arborizations of 16 juxtacellularly stained cortical pyramidal cells were analyzed. Corticostriatal neurons were located in the medial agranular or anterior cingulate cortex of rats. All axons were of the extended type and formed synaptic contacts in both the striosomal and matrix compartments as determined by counterstaining for the mu-opiate receptor. Six axonal arborizations were from collaterals of brain stem-projecting cells and the other 10 from bilaterally projecting cells with no brain stem projections. The distribution of synaptic boutons along the axons were convolved with the average dendritic tree volume of spiny projection neurons to obtain an axonal innervation volume and innervation density map for each axon. Innervation volumes varied widely, with single axons occupying between 0.4 and 14.2% of the striatum (average = 4%). The total number of boutons formed by individual axons ranged from 25 to 2,900 (average = 879). Within the innervation volume, the density of innervation was extremely sparse but inhomogeneous. The pattern of innervation resembled matrisomes, as defined by bulk labeling and functional mapping experiments, superimposed on a low background innervation. Using this sample as representative of all corticostriatal axons, the total number of corticostriatal neurons was estimated to be 17 million, about 10 times the number of striatal projection neurons.

Alcohol, tobacco, diet and the risk of oral cancer: a pooled analysis of three case-control studies

This combined analysis of data from three large case-control studies of oral cancer confirms the important effect of tobacco in the aetiology of the disease. The studies have been conducted in the United States, Italy and China and results for risks associated with tobacco smoking were generally consistent across centres, while those for alcohol were not; increased risks amongst alcohol drinkers were evident in two centres but not in the study conducted in Turin, Italy. In addition, the combined analysis had large enough numbers to analyse the risk of tobacco consumption in non-drinkers. In females these showed increased risks while in males the effect of tobacco alone was weaker. Given the popularity of tobacco smoking, and its consequent high attributable risk in terms of oral cancer it is reassuring, in terms of public health, that cessation will result in a substantial reduction in risk; a 30% reduction in risk for those stopping smoking between 1 and 9 years, and a 50% reduction for those stopping more than 9 years. Although encouraging smokers to stop should be the principal aim, decreases in risk for everyone could be achieved by encouraging high fruit and vegetable consumption.

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene and Polychlorinated Biphenyls and Breast Cancer: Combined Analysis of Five U.S. Studies

BACKGROUND

Environmental exposure to organochlorines has been examined as a potential risk factor for breast cancer. In 1993, five large U.S. studies of women located mainly in the northeastern United States were funded to evaluate the association of levels of 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE) and polychlorinated biphenyls (PCBs) in blood plasma or serum with breast cancer risk. We present a combined analysis of these results to increase precision and to maximize statistical power to detect effect modification by other breast cancer risk factors.

METHODS

We reanalyzed the data from these five studies, consisting of 1400 case patients with breast cancer and 1642 control subjects, by use of a standardized approach to control for confounding and assess effect modification. We calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs) by use of the random-effects model. All statistical tests were two-sided.

RESULTS

When we compared women in the fifth quintile of lipid-adjusted values with those in the first quintile, the multivariate pooled OR for breast cancer associated with PCBs was 0.94 (95% CI = 0.73 to 1.21), and that associated with DDE was 0.99 (95% CI = 0.77 to 1.27). Although in the original studies there were suggestions of elevated breast cancer risk associated with PCBs in certain groups of women stratified by parity and lactation, these observations were not evident in the pooled analysis. No statistically significant associations were observed in any other stratified analyses, except for an increased risk with higher levels of PCBs among women in the middle tertile of body mass index (25-29.9 kg/m(2)); however, the risk was statistically nonsignificantly decreased among heavier women.

CONCLUSIONS

Combined evidence does not support an association of breast cancer risk with plasma/serum concentrations of PCBs or DDE. Exposure to these compounds, as measured in adult women, is unlikely to explain the high rates of breast cancer experienced in the northeastern United States.

Use of the tetracycline-controlled transcriptional silencer (tTS) to eliminate transgene leak in inducible overexpression transgenic mice

The doxycycline-inducible reverse tetracycline transactivator (rtTA) is frequently used to overexpress transgenes in a temporally regulated fashion in vivo. These systems are, however, often limited by the levels of transgene expression in the absence of dox administration. The tetracycline-controlled transcriptional silencer (tTS), a fusion protein containing the tet repressor and the KRAB-AB domain of the kid-1 transcriptional repressor, is inhibited by doxycycline. We hypothesized that tTS would tighten control of transgene expression in rtTA-based systems. To test this hypothesis we generated mice in which the CC10 promoter targeted tTS to the lung, bred these mice with CC10-rtTA-interleukin 13 (IL-13) mice in which IL-13 was overexpressed in an inducible lung-specific fashion, and compared the IL-13 production and phenotypes of parental mice and the triple transgenic CC10-rtTA/tTS-IL-13 progeny of these crosses. In the CC10-rtTA-IL-13 mice, IL-13, mucus metaplasia, inflammation, alveolar enlargement, and enhanced lung volumes were noted at base line and increased greatly after doxycycline administration. In the triple transgenic tTS animals, IL-13 and the IL-13-induced phenotype could not be appreciated without doxycycline. In contrast, tTS did not alter the induction of IL-13 or the generation of the IL-13 phenotype by doxycycline. Thus, tTS effectively eliminated the baseline leak without altering the inducibility of rtTA-regulated transgenes in vivo. Optimal "off/on" regulation of transgene expression can be accomplished with the combined use of tTS and rtTA.

Evidence for multiclonality in multicentric Kaposi's sarcoma

Kaposi's sarcoma (KS) develops in a variety of clinical states and is the most common tumor seen in patients with HIV-1 infection. KS develops as a multifocal mucocutaneous disease with subsequent spread to visceral organs, and it has been argued to be a benign proliferation caused by its multifocality at initial presentation, lack of aneuploidy, and spontaneous regression upon withdrawal of immunosuppressive agents in iatrogenically induced disease. We wished to determine whether KS lesions are clonal, indicative of a true neoplasm. Also, we tested whether multifocal KS lesions are clonally related, derived from a common progenitor cell or of independent cellular origin. We studied the X-chromosome inactivation pattern of the human androgen receptor gene in tumor biopsies of women with KS. This procedure tests for the clonality of a tissue specimen, a hallmark of neoplasia. Each specimen was microdissected to minimize normal cell contamination. Of 12 evaluable cases, 10 were HIV-seropositive and 2 were HIV-seronegative. Twenty-four biopsies from the 12 patients were examined. Five cases were consistent with individual KS lesions being clonal. In two cases, multiple KS specimens derived from the individual patients had different androgen receptor alleles inactivated, proving unequivocally that these KS lesions arose independently from distinct transformed cells. In seven cases, only a polyclonal pattern of inactivation was observed, whereas two others had tumor areas of both clonal and polyclonal inactivation patterns. These findings suggest that KS can be a clonal neoplasm, and in some of the cases multiple KS lesions in a given patient can arise from independent cellular origins and acquire clonal characteristics. The polyclonal inactivation pattern observed in other KS lesions may represent a premalignant stage or false negative results.

The effects of preparations of human chorionic gonadotropin on AIDS-related Kaposi's sarcoma

BACKGROUND

Kaposi's sarcoma is the most common cancer in patients with the acquired immunodeficiency syndrome (AIDS). Recently, certain preparations of human chorionic gonadotropin (hCG) have been shown to inhibit the growth of Kaposi's sarcoma cell lines in vitro and in immunodeficient mice.

METHODS

After in vitro evaluation of four commercially available hCG preparations, the most active product was evaluated in 36 patients with AIDS-related Kaposi's sarcoma. In a phase 1-2 trial, 24 patients received intralesional injections of hCG three times a week for two weeks at doses of 250, 500, 1000, or 2000 IU (6 patients each). In each patient three nodular lesions were injected, two with the drug and one with diluent alone. In a double-blind trial, 12 additional patients were randomly assigned to receive intralesional injections of 2000 IU of hCG or diluent alone (6 patients each; two lesions per patient). At the conclusion of therapy, the lesions were measured, their gross appearance assessed, and biopsy specimens evaluated.

RESULTS

A.P.L. (Wyeth-Ayerst), which had the most in vitro activity against Kaposi's sarcoma cell lines, was selected for the clinical investigation. Treatment with A.P.L. was well tolerated at all doses. In the cohorts given 250, 500, 1000, and 2000 IU, 1, 5, 5, and 10 of the 12 injected lesions responded, respectively (P=0.03 for trend). Complete tumor regression was observed in one lesion each at the 250-IU and 500-IU doses, in two lesions given the 1000-IU dose, and in five lesions given the 2000-IU dose. In the double-blind study, none of the 12 lesions in the six patients injected with diluent had responses, as compared with 10 of the 12 lesions in the six patients injected with hCG (P=0.015). Microscopical evidence of apoptosis was observed only in hCG-treated lesions. The percentage of cells that died increased in a dose-dependent manner (P<0.001). Serum levels of follicle-stimulating hormone (P=0.002) and luteinizing hormone (P=0.001) declined after the last injection of hCG, but there was no effect on these hormones in the diluent-treated patients.

CONCLUSIONS

The intralesional injection of hCG induces the regression of AIDS-related Kaposi's sarcoma lesions in a dose-dependent manner. The response of these tumors appears to be mediated by the induction of apoptosis.

Mechanisms of hydrogen peroxide-induced contraction of rat aorta

It has been suggested that reactive oxygen species may be involved in the regulation of vascular tone. However, the underlying mechanisms remain to be elucidated. The present studies were designed to investigate the contractile effects of hydrogen peroxide (H2O2), one of the reactive oxygen species, on isolated ring segments of rat aorta with and without endothelium. H2O2 induced an endothelium-independent contraction in isolated rat aorta ring segments in a concentration-dependent manner at concentrations from 5 x 10(-6) to 5 x 10(-3) M. H2O2-induced contractions of denuded rat aorta rings were stronger than those on intact rat aorta segments. The contractile effects of H2O2 were inhibited completely by 1200 u/ml catalase. The presence of 1.0 microM Fe2+ or 10 microM proadifen, a cytochrome P450 monooxygenase inhibitor, potentiated the contractile effect of H2O2 on isolated rat aorta segments. 1 mM deferoxamine (a Fe2+ chelator) or 100 microM dimethyl sulfoxide (a hydroxyl radical scavenger) significantly attenuated the vessel contractions induced by hydrogen peroxide plus Fe2+ or hydrogen peroxide itself. Removal of extracellular Ca2+ ([Ca2+]0), addition of 5 microM verapamil, administration of a protein kinase C inhibitor (staurosporine), treatment with an inhibitor of protein tyrosine phosphorylation (genistein) or employment of 5.0 microM indomethacin resulted in a significant attenuation of the contractile responses of the vessels to H2O2. Pharmacological antagonists (e.g. a muscarinic acetylcholine receptor antagonist (atropine), an antagonist of histamine H1 receptors (diphenhydramine), an antagonist of histamine H2 receptors (cimetidine), an alpha-adrenoceptor antagonist (phentolamine), a beta-adrenoceptor antagonist (propranolol) and an antagonist of serotonin receptor (methysergide)) did not inhibit or attenuate the contractions induced by H2O2. Exposure of primary aortic smooth muscle cells to H2O2 (5 x 10(-6) to 5 x 10(-3) M) produced significant rises of intracellular Ca2+ ([Ca2+]i) within 20 s. Employment of 1.0 microM Fe2+ markedly enhanced the increment in [Ca2+]i in the smooth muscle cells. 10 microM proadifen treatment failed to alter the hydrogen peroxide-induced increment in [Ca2+]i of the smooth muscle cells. However, the presence of 5 microM indomethacin significantly attenuated the rise in [Ca2+]i in smooth muscle cells. The present results suggest that H2O2 can induce contractions of rat aorta segments, at pathophysiological concentrations, which are Ca2+-dependent. Hydroxyl radicals (.OH), cyclooxygenase products, protein kinase C and products of protein tyrosine phosphorylation appear to play some role in hydrogen peroxide-induced contractions. Metabolites catalyzed by cytochrome P450-dependent enzymes (upon treatment with hydrogen peroxide) appear to exert a vasodilator effect on rat aorta segments. Lastly, some unidentified mediators, produced by a cytochrome P450 inhibitor (proadifen), during hydrogen peroxide treatment, appear to play some role in contraction of vascular smooth muscle of rat aorta segments in vitro.

Epidemiology of non-Hodgkin lymphoma in Connecticut. 1935-1988

BACKGROUND

During the past decades, there have been reports of increases in the incidence and mortality rates due to non-Hodgkin lymphoma (NHL) in many parts of the world. The risk factors responsible for the increasing incidence are largely unknown. This study provided an overview of the incidence pattern of NHL in Connecticut and generated hypotheses for additional investigation.

METHODS

This study was based on all the NHL cases reported to the Connecticut Tumor Registry (CTR) between 1935 and 1988. Crude, age-adjusted, and age-specific incidence rates of NHL were calculated for each sex. Age-adjusted incidence rates were calculated by the direct method standardized to the 1970 United States standard million population. The data are presented by calendar year and cohort year of birth to examine the secular trends and birth cohort effects. Racial information was not coded before 1957 and is of uncertain validity until the early 1970s; therefore, racial analysis was restricted to 1970-1988. Analyses by histologic subtypes and by anatomic sites were restricted to the last 3 decades (1960-1988) because more accurate classification systems were used during this time.

RESULTS

A total of 11,326 newly diagnosed cases of NHL were included in the study. Of them, 5866 (52%) were diagnosed in men and 5460 (48%) were diagnosed in women. The study results indicated that the incidence rate of NHL has been increasing during the past decades for men and women, whites and blacks, nodular NHL and diffuse NHL, disease originating from lymph nodes and disease originating from other sites, and in all age groups, especially the older age groups. Birth cohort examination did not show any indication of a decline or levelling off in incidence rates among recent birth cohorts. Age-specific incidence rates in both sexes suggested that the rates increase with age, with a sharp increase beginning at 50 years of age and peaking at 80 years of age. Men had a 30% higher incidence rate than women, and whites had approximately 1.5 times the age-adjusted incidence rate of blacks.

CONCLUSIONS

The results indicated that the incidence rate of NHL has been increasing in Connecticut during the past decades and is likely to continue to rise in the coming years. Analytical epidemiologic studies are needed to examine the risk factors that might account for the increase in NHL.

Agricultural exposure to carbamate pesticides and risk of non-Hodgkin lymphoma

Recent epidemiological studies have suggested an increased risk of non-Hodgkin lymphoma (NHL) from carbamate insecticide use among farmers. To further explore the possible relationships, we conducted a pooled analysis of three population-based case-control studies conducted in four midwestern states in the United States. A total of 985 white male subjects and 2895 control subjects were included in this analysis. Unconditional logistic regression was used to estimate the association and control for confounding. Compared with nonfarmers, farmers who had ever used carbamate pesticides had a 30% to 50% increased risk of NHL, whereas farmers without carbamate pesticide use showed no increased risk. Analyses for individual carbamate pesticides found a more consistent association with Sevin but not carbofuran, butylate, or S-ethyl dipropylthiocarbamate plus protectant. Among farmers using Sevin, the risk of NHL was limited to those who personally handled the product, those who first used the product for > or = 20 years before their disease diagnosis, and those who used the product for a longer period. These associations persisted after adjusting for other major classes of pesticides. These results suggest an increased risk of NHL associated with carbamate pesticide use, particularly Sevin. Further investigation of the association is warranted.

Advanced breast cancer incidence following population-based mammographic screening

BACKGROUND

Breast cancer mortality is declining in many Western countries. If mammography screening contributed to decreases in mortality, then decreases in advanced breast cancer incidence should also be noticeable.

PATIENTS AND METHODS

We assessed incidence trends of advanced breast cancer in areas where mammography screening is practiced for at least 7 years with 60% minimum participation and where population-based registration of advanced breast cancer existed. Through a systematic Medline search, we identified relevant published data for Australia, Italy, Norway, Switzerland, The Netherlands, U.K. and the U.S.A. Data from cancer registries in Northern Ireland, Scotland, the U.S.A. (Surveillance, Epidemiology and End Results (SEER), and Connecticut), and Tasmania (Australia) were available for the study. Criterion for advanced cancer was the tumour size, and if not available, spread to regional/distant sites.

RESULTS

Age-adjusted annual percent changes (APCs) were stable or increasing in ten areas (APCs of -0.5% to 1.7%). In four areas (Firenze, the Netherlands, SEER and Connecticut) there were transient downward trends followed by increases back to pre-screening rates.

CONCLUSIONS

In areas with widespread sustained mammographic screening, trends in advanced breast cancer incidence do not support a substantial role for screening in the decrease in mortality.

A case-control study of oral cancer in Beijing, People's Republic of China. Associations with nutrient intakes, foods and food groups

A case-control study of oral cancer was conducted in Beijing, People's Republic of China to examine the association between dietary nutrient intake and risk of oral cancer, both in terms of estimated intake of nutrients and micro-nutrients, and in terms of specific foods and food groups. The study was hospital-based and controls were hospital in-patients matched for age and sex with the cases. The response rate for cases and controls was 100% and 404 case/control pairs were interviewed. The results suggest that increased protein and fat intake are related to a decreased risk of oral cancer. Carbohydrate intake, however, showed a moderate increased risk for oral cancer. Total carotene intake and carotene intake from fruits and vegetables are inversely associated with risk of oral cancer. A similar pattern was observed for dietary vitamin C intake. Dietary fibre derived from fruits and vegetables showed a strong negative association with oral cancer risk, but fibre derived from other sources did not exhibit any protective effect. At the level of foods and food groups, increased consumption of fresh meat, chicken and liver was significantly associated with a reduction in oral cancer risk: the tests for trend were all statistically significant at the P < 0.01 level. Consumption of common carp, hairtail, shrimp and lobster were also associated with decreased risk. Risk was found to increase with increasing consumption of millet and corn bread (P < 0.01) but to decrease with increasing consumption of rice (P < 0.01). Increased consumption of grapes, bananas, oranges, tangerines, peaches and pears were associated with reduced risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental expression of the alpha 6 GABAA receptor subunit mRNA occurs only after cerebellar granule cell migration

Using a competitive polymerase chain reaction (PCR) and appropriate internal standards, we have analyzed absolute amounts of the alpha 6 GABAA receptor subunit mRNA in the postnatally developing cerebellum and neocortex. The PCR data have shown that absolute amounts of the alpha 6 receptor subunit mRNA in the cerebellum increase dramatically (nearly 100-fold) during the second postnatal week, reaching maximal levels by postnatal day 21 (1 fmol/microgram total RNA). The absolute amount of the alpha 6 GABAA receptor subunit mRNA in the cortex at postnatal day 1 was 2 amol/microgram total RNA and increased to 7 amol/micrograms total RNA by postnatal day 14. No further increase in alpha 6 mRNA expression in the adult cortex was observed. Microscopic analysis of emulsion coated and counterstained sections indicated that alpha 6 GABAA receptor subunit mRNA labeling was only detected in the internal granule cell layer and not in either the external granule cell layer or in migrating granule cells. The alpha 1 GABAA receptor subunit mRNA increased in the cerebellar cortex with a similar temporal profile, although its distribution extended to additional cell types (Purkinje cells, stellate/basket cells and possibly cerebellar astrocytes). The temporal expression of these two GABAA receptor subunit mRNAs is coincident with the formation of synaptic contacts in the granule cell dendrites suggesting that afferent pathways innervating these neurons following cell migration may play a critical role in increasing the expression of mRNAs encoding the alpha 1 and alpha 6 GABAA receptor subunits.

The continuing increase in adenocarcinoma of the uterine cervix: a birth cohort phenomenon

BACKGROUND

Adenocarcinoma of the uterine cervix has been reported to be increasing among young white women and earlier studies suggest a birth cohort pattern for the observed increase. No study, however, has examined the time trends of adenocarcinoma of the cervix by birth cohort.

METHODS

Using Surveillance, Epidemiology, and End Results (SEER) data through 1990, the current study is designed to examine the time trends of invasive adenocarcinoma by birth cohort. An age-period-cohort model was fitted to the annual-age-specific rates to identify the components of birth cohort and time period as determinants of the observed time trends.

RESULTS

The results from this study clearly show that invasive adenocarcinoma of the uterine cervix has been increasing in both whites and blacks, but the increase is statistically significant only among whites, reaching 4.2 percent per year for those born since 1935. The results also show that the recent increase in invasive adenocarcinoma started among those born around the mid 1920s, and a strong birth cohort effect is largely responsible for the observed increase.

CONCLUSION

Invasive adenocarcinoma of the uterine cervix is increasing among recent birth cohorts. Analytical epidemiological studies are urgently needed to explore the risk factors responsible for the increase. The time trends for adenocarcinoma of the cervix should also be carefully monitored in the coming years.

Time trend and the age-period-cohort effect on the incidence of histologic types of lung cancer in Connecticut, 1960-1989

BACKGROUND

Recent epidemiologic studies have suggested changing patterns of lung cancer incidence by histologic type. The observed time trends have been attributed to a change in the rate of cigarette smoking, changes in exposure to new environmental carcinogens, and changes in the criteria for the histopathologic diagnosis of lung cancer. The current study was designed to examine the incidence patterns of lung cancer by histologic type in Connecticut and to use this information to project the future trend of the disease in this population.

METHODS

This study was based on all the lung cancer cases reported to the Connecticut Tumor Registry between 1960 and 1989. On the basis of this data set, crude and age-adjusted incidence rates of lung cancer were calculated by histologic type for each sex. The age-specific incidence rates are presented by calendar year and cohort year of birth. A regression model was used to identify birth cohort, period, and age as determinants of the observed time trends.

RESULTS

For the overall age-adjusted incidence rates, squamous cell carcinoma and small cell carcinoma have stabilized in men, whereas they are still increasing in women. The incidence of adenocarcinoma has been increasing in both men and women, but there has been a much sharper incidence among females since the mid-1970s. An examination of age-specific incidence rates by birth cohort and the results from age-period-cohort modeling indicate that incidences of all three major histologic types of lung cancer in the recent birth cohorts either have started decreasing (squamous cell carcinoma) or shown a clear reduction in the rate of increase (adenocarcinoma and small cell carcinoma). This study, however, did not indicate an increase of bronchoalveolar lung carcinoma, which was reported by other clinically based studies.

CONCLUSION

While the overall age-adjusted incidence rates showed different incidence patterns for different histologic types of lung cancer, a decreasing or stabilized rate for all three major histologic types of lung cancer was observed in recent birth cohorts in both males and females. The observed incidence pattern is consistent with smoking trends over time including changes in smoking prevalence and the consumption of low tar and filter cigarettes. It is expected that if the current trend in tobacco smoking continues and if there are no major changes in other risk factors for lung cancer, a forthcoming stabilization or decrease in the rate of lung cancer incidence for all major histologic types (including adenocarcinoma) in both sexes in Connecticut could be anticipated.