Segregation analysis of breast cancer: a comparison of type-dependent age-at-onset versus type-dependent susceptibility models

Most segregation analyses of breast cancer susceptibility have modeled the effect of the major gene on the age-at-onset distribution. However, in families linked to BRCA1 or BRCA2, there is wide variation in the age-at-onset among gene carriers. We performed a segregation analysis of 544 Minnesota breast cancer families using models which parameterized the putative major gene effect in two ways: earlier age-at-onset, with a common level of susceptibility (model I), and greater susceptibility, with a common mean age-at-onset (model II). Five hypothetical modes of transmission and an unrestricted general hypothesis were fitted to the data. Twice the difference between the log(e) likelihood for the data under the specified hypothesis (recessive, no major gene, etc.) and the log(e) likelihood under the general hypothesis is distributed asymptotically as a chi-square statistic with the degrees of freedom equal to the difference in the number of parameters estimated. This difference was compared to the critical value for the chi-square distribution to assess goodness-of-fit. Under model I, both Mendelian and non-Mendelian hypotheses were rejected. When model II was used, the non-Mendelian hypotheses were rejected whereas all Mendelian hypotheses were not. Mendelian recessive inheritance of a common allele (qA = 0.11) with a high penetrance (87%) provided the best fit to the data. We then stratified the families into two subsets based on the age at diagnosis of the proband [< or = 55 years (n = 265) versus > 55 years (n = 279)]; there was no evidence of heterogeneity under either model (I or II). These data suggest that, in some breast cancer families, the effect of the putative susceptibility gene is better represented as increasing overall susceptibility to breast cancer rather than as a shift in the age-at-onset distribution.

Mucinous adenocarcinoma of the endometrium with intestinal differentiation: a case report

Mucinous differentiation of endocervical type has been well documented in endometrial carcinoma. However, we describe an unusual case of adenocarcinoma of the endometrium showing diffuse histological, immunohistochemical, and ultrastructural evidence of intestinal differentiation. Although intestinal differentiation has been described in mesodermally derived tissues including endocervix, ovary, and urinary tract, it has not been reported in normal endometrium. One previous case has been reported showing this pattern in endometrial carcinoma. Possible histogenetic mechanisms of this pattern are discussed.

Differentiation of epidemic-associated strains of Listeria monocytogenes by restriction fragment length polymorphism in a gene region essential for growth at low temperatures (4 degrees C)

The growth of Listeria monocytogenes in food stored in the cold has often been implicated in outbreaks of listeriosis. Many subtyping schemes have suggested that epidemic-associated strains belong to a unique genetic group. It has not yet been possible, however, to identify molecular or bacteriologic markers unique to epidemic-associated strains. Recently we cloned three genes of L. monocytogenes, ltrA, ltrB, and ltrC, which are essential for growth at low temperatures (4 degrees C). The use of a 1.2-kb PstI fragment derived from ltrB as a probe in Southern blots of HindIII-digested DNA revealed three hybridization patterns: the first (a 5.0-kb band) was observed in strains of serotypes 4b, 1/2b, and 3b; the second (a 3.1-kb band) was seen in strains of serotypes 1/2a, 3a, 1/2c, and 3c; and the third (a 9.5-kb band) was characteristic of epidemic-associated serotype 4b strains. These and other data suggest that probes derived from this gene region that is essential for growth at low temperatures can be useful molecular tools for the subtyping of strains implicated in food-borne listeriosis.

Retinol, antioxidant vitamins, and cancers of the upper digestive tract in a prospective cohort study of postmenopausal women

Very few prospective studies have reported previously on the association of micronutrient intake and the risk of cancers of the upper digestive tract (mouth, pharynx, esophagus, and stomach) in western populations. During 7 years of follow-up in the Iowa Women's Health Study, from 1986-1992, 59 of the 34,691 at-risk cohort members developed cancers of the upper digestive tract. The association of retinol and antioxidant vitamins (carotene and vitamins C and E) were evaluated separately for cancers of the mouth/pharynx/esophagus (n = 33) and stomach (n = 26). After adjustment for age, smoking, and total energy intake, higher intakes of carotene and vitamins C and E were related to lower risks of both oral/pharyngeal/esophageal and gastric cancers, while retinol was associated with lower risk of gastric cancer only. The dose-response relation between gastric cancer risk and intake of carotene was clear and statistically significant, with relative risks of 0.6 and 0.3, respectively, observed among women in the upper two versus the lowest tertiles of intake. This study provides further evidence that higher intake of antioxidant vitamins may be important in the prevention of cancers of the upper digestive organs.

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.

Acquired neuromyotonia: evidence for autoantibodies directed against K+ channels of peripheral nerves

Acquired neuromyotonia is characterized by hyperexcitability of motor nerves leading to muscle twitching, cramps, and weakness. The symptoms may improve following plasma exchange, and injection of immunoglobulin G (IgG) from 1 neuromyotonia patient into mice increased the resistance of neuromuscular transmission to d-tubocurarine. Here we examine nerves and muscle in vitro from mice injected with plasma or purified IgG from 6 neuromyotonia patients or pooled control subjects, and cultured dorsal root ganglion cells after treatment with IgG. Three of the patients had antibodies against human voltage-gated potassium channels labeled with 125I-alpha-dendrotoxin. The quantal release of acetylcholine (quantal content) at end-plates in diaphragms from mice treated with neuromyotonia IgG preparations was increased by 21% relative to control values (p = 0.0053). With one IgG preparation, the duration of the superficial peroneal nerve compound action currents was increased by 93%. The dorsal root ganglion cells treated with this IgG showed a marked increase in repetitive firing of action potentials. All effects were similar to those obtained with aminopyridines. We conclude that at least some patients with acquired neuromyotonia have antibodies directed against aminopyridine- or alpha-dendrotoxin-sensitive K+ channels in motor and sensory neurons, and they are likely to be implicated in the disease process.

Retinol, antioxidant vitamins, and cancers of the upper digestive tract in a prospective cohort study of postmenopausal women

Very few prospective studies have reported previously on the association of micronutrient intake and the risk of cancers of the upper digestive tract (mouth, pharynx, esophagus, and stomach) in western populations. During 7 years of follow-up in the Iowa Women's Health Study, from 1986-1992, 59 of the 34,691 at-risk cohort members developed cancers of the upper digestive tract. The association of retinol and antioxidant vitamins (carotene and vitamins C and E) were evaluated separately for cancers of the mouth/pharynx/esophagus (n = 33) and stomach (n = 26). After adjustment for age, smoking, and total energy intake, higher intakes of carotene and vitamins C and E were related to lower risks of both oral/pharyngeal/esophageal and gastric cancers, while retinol was associated with lower risk of gastric cancer only. The dose-response relation between gastric cancer risk and intake of carotene was clear and statistically significant, with relative risks of 0.6 and 0.3, respectively, observed among women in the upper two versus the lowest tertiles of intake. This study provides further evidence that higher intake of antioxidant vitamins may be important in the prevention of cancers of the upper digestive organs.

[Posterior chamber intraocular lens implantation in the absence of posterior capsular support]

The authors retrospectively studied the clinical records of 15 eyes without posterior capsular support receiving transscleral ciliary sulcus fixation of posterior chamber intraocular lenses. Postoperative followup period range from 2 weeks to 8 months, an average of 2.2 months. Postoperative visual acuity improved in all patients, 20% of which had 0.6 or better and 40%-between 0.2 and 0.5. Lens rotation was the primary complication and accounted for poor acuity in some cases. The results indicate that ciliary sulcus fixation in the absence of posterior capsular support appears to be safe and effective and may represent a significant advance in anterior segment surgery.

Genetic transfer of a nonpeptide antagonist binding site to a previously unresponsive angiotensin receptor

Mutational analysis based on the pharmacological differences between mammalian and amphibian angiotensin II receptors (AT receptors) previously identified 7 aa residues located in transmembrane domains (TMs) III (Val-108), IV (Ala-163), V (Pro-192, Thr-198), VI (Ser-252), and VII (Leu-300, Phe-301) of the rat AT receptor type 1b (rAT1b receptor) that significantly influenced binding of the nonpeptide antagonist Losartan. Further studies have shown that an additional 6 residues in the rAT1b receptor TMs II (Ala-73), III (Ser-109, Ala-114, Ser-115), VI (Phe-248), and VII (Asn-295) are important in Losartan binding. The 13 residues required for Losartan binding in the mammalian receptor were exchanged for the corresponding amino acids in the Xenopus AT receptor type a (xATa receptor) to generate a mutant amphibian receptor that bound Losartan with the same affinity as the rAT1b receptor (Losartan IC50 values: rAT1b, 2.2 +/- 0.2 nM: xATa, > 50 microM; mutant, 2.0 +/- 0.1 nM). To our knowledge, this is the first report of a gain-of-function mutant in which the residues crucial to formation of a ligand binding site in a mammalian peptide hormone receptor were transferred to a previously unresponsive receptor by site-directed mutagenesis. Ala substitutions and comparison of mammalian and amphibian combinatorial mutants indicated that TM III in the rAT1b receptor plays a key role in Losartan binding. Identification of residues involved in nonpeptide ligand binding will facilitate studies aimed at elucidating the chemical basis for ligand recognition in the AT receptor and peptide hormone receptors in general.

Association of body mass index and body fat distribution with risk of lung cancer in older women

Obesity has been associated with an increased risk of cancer at a number of sites. A notable exception appears to be lung cancer, for which several studies suggest a modest inverse association. However, cigarette smoking is directly associated with lung cancer and inversely associated with body mass index. To investigate the hypothesis that body mass index is associated with lung cancer independent of cigarette smoking, the authors analyzed data from a prospective cohort study of 41,837 Iowa women aged 55-69 years at baseline in 1986. In addition, they examined whether central adiposity (high waist/hip ratio) was associated with lung cancer incidence. Through 1992 (6 years of follow-up), 233 cases of lung cancer were identified through the State Health Registry of Iowa. The body mass index at several ages was calculated from self-reports of height at baseline and weights at ages 18, 30, 40, and 50 years and at baseline. Current and former smokers generally had lower mean body mass indices than did nonsmokers at all ages except 18 years. Cases generally had lower body mass indices than did noncases at all ages except 18 and 30 years but, among current smokers, cases had higher mean body mass indices than did noncases at all ages except baseline, although the differences were not statistically significant. An apparent positive association of a high waist/hip ratio with lung cancer in the total cohort was found to be primarily accounted for by a higher waist/hip ratio in current and former smokers. When stratified by smoking status and adjusted for other risk factors, including age and pack-years of smoking, the body mass index at baseline, body mass index at age 50 years, and waist/hip ratio were not associated with lung cancer. The results of multivariate analyses suggest that the inverse association of body mass index with lung cancer can be explained by smoking status and that the positive association of waist/hip ratio with lung cancer can be explained by pack-years of smoking.

Dietary intake of energy and animal foods and endometrial cancer incidence. The Iowa women's health study

To assess the relations of dietary intake of energy and animal foods to endometrial cancer risk, dietary analyses were performed using data from a prospective cohort study of over 23,000 postmenopausal Iowa women who responded to a mailed questionnaire in 1986 and were followed through the end of 1992 for cancer incidence and total mortality. Usual intakes of 127 food items were measured by a semiquantitative food frequency questionnaire. After 7 years of follow-up, 216 incident endometrial cancer cases had been ascertained. There was no statistically significant association of dietary intake of energy and most animal foods with endometrial cancer incidence over the 7-year follow-up period. Stratified analyses, however, suggested that intake of energy from plant foods may be inversely associated with endometrial cancer risk in the latter years of follow-up (trend test, p = 0.03), while high intake of energy and foods from animal sources related to slightly, but not statistically significantly, elevated risks of this cancer in the earlier years of follow-up. The only significant dose-response relation observed in food group analyses was for processed meat and fish, for which a significant 50% excess risk of endometrial cancer was found among women in the highest versus the lowest tertile of intake. This study suggests that dietary intake of energy and most animal foods is not related to or is only weakly related to the risk of endometrial cancer among postmenopausal US women.

Hormonal replacement therapy and morbidity and mortality in a prospective study of postmenopausal women

We assessed the association of hormonal replacement therapy with mortality and incidence of multiple diseases in over 40,000 postmenopausal women followed for 6 years as part of the Iowa Women's Health Study. Compared with women who never used hormone replacement therapy, current users had multivariate adjusted relative risks (RR) as follows: total mortality (RR = 0.78; 95% confidence interval [CI] = 0.65, 0.94), coronary heart disease mortality (RR = 0.74; 95% CI = 0.48, 1.12), endometrial cancer incidence (RR = 4.3; 95% CI = 2.7, 6.9), breast cancer incidence (RR = 1.23; 95% CI = 0.99, 1.55), colon cancer incidence (RR = 0.72; 95% CI = 0.46, 1.12), and hip fracture incidence (RR = 0.53; 95% CI = 0.31, 0.91).

Excimer laser photorefractive keratectomy for myopia in China. A report of 750 eyes with a 6-month follow-up

A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to -6.00D, 587 eyes), uncorrected visual acuity was improved to 20/20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of +/- 1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20/20 or better and 89.4% of the eyes were within +/- 1.00D. The designed predictability of the two groups was the same (P > 0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by corneal topography and modulation by steroid.

An analysis on follow-up results of photoreactive keratectomy for treatment of myopia

A prospective study of excimer laser photorefractive keratectomy (PRK) was performed with the aim of correcting a range of myopic errors between -1.00 and -10.00 diopters on 422 myopic eyes that were followed for more than one year. At postoperative one year, 91.4% of the eyes had uncorrected visual acuity of 20/20 or better, and 97.4% were within +/- 1.00 diopter of the desired emmetropia, and the corneal haze disappeared in most of the eyes. Elevated intraocular pressures were observed in 20.4% of the eyes. The decrease of one line of the best corrected visual acuity occurred in 7.6% and of two lines in 0.5% of the eyes. We think that the excimer laser PRK is a very predictable, safe, stable, and effective method to correct myopia up to -10.00 D, and longer follow-up will be necessary.

Endocrine, gonadal and behavioral responses of male crucian carp to the hormonal pheromone 17 alpha,20 beta-dihydroxy-4-pregnen-3-one

The olfactory-mediated responses to the sex hormone 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-P) were studied in spermiated and regressed male crucian carp (Carassius carassius L.). The position and spontaneous locomotor activity of single male crucian carp were continuously recorded in an artificial stream. 17 alpha,20 beta-P (final concentration 10(-11) M) was supplied to one half and its ethanol carrier to the other half of the test area. Milt volume and gonadotropin (GtH-II) concentration in the plasma were also measured. The smell of 17 alpha,20 beta-P significantly increased both the GtH-II concentration in the plasma and the volume of strippable milt in spermiated crucian carp. Behaviorally, the side of the test area scented with 17 alpha,20 beta-P was significantly avoided by spermiated males. None of the described effects of 17 alpha,20 beta-P on spermiated males were observed for the regressed crucian carp. In view of the lack of response from regressed crucian carp we suggest that the observed avoidance behavior of 17 alpha,20 beta-P by spermiated males is a relevant reaction for spawning male crucian carp. The results are well in accordance with responses obtained in the closely related goldfish and gives strong support that the wild male crucian carp use the 17 alpha,20 beta-P signal from the females to prepare for the coming spawning.

[Glucocorticoid-induced ocular hypertension after photorefractive keratectomy]

1,628 myopic eyes were performed with excimer laser photorefractive keratectomy (PRK) and 1% prednisolon eyedrops was used for postoperative regime. All patients after PRK were followed 2-14 months, 9.89% had an intraocular pressure of more than 2.933 kPa (22mmHg) at first month and 15.05% at third month. Male patients showed higher response to glucocorticoid than female patients. There was no correlation between elevations of intraocular pressue and refractive powers.

Behavioural and endocrinological responses of mature male goldfish to the sex pheromone 17alpha,20beta-dihydroxy-4-pregnen-3-one in the water

The behavioural response of spermiated male goldfish to the sex pheromone 17alpha,20ss-dihydroxy-4-pregnen-3-one (17alpha,20ss-P) in the ambient water was measured using a computerized video-image analysis system. The position and spontaneous locomotor activity of single spermiated male goldfish were continuously recorded in an artificial stream. 17alpha,20ss-P (final concentration 10(-11) mol l-1) was supplied to one half and its ethanol carrier to the other half of the test area. The results showed that the fish spent significantly less time in water scented with 17alpha,20ss-P than in control water. Moreover, both the spontaneous locomotor activity and the gonadotropin II concentration in the plasma increased significantly because of contact with 17alpha,20ss-P in the ambient water. The swimming speed was unchanged, whether the fish resided in the 17alpha,20ss-P section or in the section without 17alpha,20ss-P added. In view of the complex dual hormone-pheromone system in goldfish, the possibility of an additional function of 17alpha,20ss-P is discussed. Because the release of the pheromone 17alpha,20ss-P occurs before ovulation and the level then drops drastically, we suggest that the avoidance reaction observed allows the sexually mature male to avoid misdirected courting of non-ovulated females and thus to continue its search for an ovulated female.

Cloning and characterization of a calcium channel alpha 1 subunit from Drosophila melanogaster with similarity to the rat brain type D isoform

We report the complete sequence of a calcium channel alpha 1 subunit cDNA cloned from a Drosophila head cDNA library. This cDNA encodes a deduced protein containing 2516 amino acids with a predicted molecular weight of 276,493. The deduced protein shares many features with vertebrate homologs, including four repeat structures, each containing six transmembrane domains, a conserved ion selectivity filter region between transmembrane domains 5 and 6, and an EF hand in the carboxy tail. The Drosophila subunit has unusually long initial amino and terminal carboxy tails. The region corresponding to the last transmembrane domain (IVS6) and the adjacent cytoplasmic domain has been postulated to form a phenylalkylamine-binding site in vertebrate calcium channels. This region is conserved in the Drosophila sequence, while domains thought to be involved in dihydropyridine binding show numerous changes. The Drosophila subunit exhibits 78.3% sequence similarity to the rat brain type D calcium channel alpha 1 subunit, and so has been designated as a Drosophila melanogaster calcium channel alpha 1 type D subunit (Dmca1D). In situ hybridization shows that Dmca1D is highly expressed in the embryonic nervous system. Northern analysis shows that Dmca1D cDNA hybridizes to three size classes of mRNA (9.5, 10.2, and 12.5 kb) in heads, but only two classes (9.5 and 12.5 kb) in bodies and legs. PCR analysis suggests that the Dmca1D message undergoes alternative splicing with more heterogeneity appearing in head and embryonic extracts than in bodies and legs.

[Photorefractive keratectomy for myopia: 6 month results]

The argon fluoride excimer laser is able to ablate the superficial cornea and to correct refractive problems. Photorefractive keratectomy (PRK) was performed on 103 myopic eyes ranging from -0.75D to -6.00D. We prospectively evaluated visual and refractive results that were followed for more than 6 months. Uncorrected visual acuity of 1.0 or better was achieved in 88.35%. The difference between attempted and achieved refractive correction was within +/- 1.00D in 94.17%. 10 eyes (9.71%) had trace to mild subepithelial hare and 19 eyes (18.45%) had loss of one line of best spectacle corrected visual acuity. The excimer laser PRK appears to be a predictable and effective method to correct myopia under -6.00D.

Infant breastfeeding and the risk of childhood lymphoma and leukaemia

BACKGROUND

A protective effect of breastfeeding on childhood lymphoma has been indicated but supportive evidence is limited.

METHOD

Data from a population-based case-control study of childhood cancer in Shanghai, including 82 lymphoma cases and 159 acute leukaemia cases and their age- and sex-matched community controls, were analysed.

RESULTS

After adjustment for potentially confounding variables, a slight, although non-significant, reduction in risk of lymphoma was observed among children who were breastfed as infants versus those who were not (odds ratio [OR] = 0.69; 95% CI: 0.3-1.7). The reduction was somewhat greater for children who had been breastfed longer and appeared to pertain primarily to Hodgkin's disease and to cases diagnosed before the age of 6 years. As expected, there was no reduction in risk of acute leukaemia associated with breastfeeding.

CONCLUSIONS

Although providing neither strong support for nor refuting the study hypothesis, these data suggest that if breastfeeding does reduce the risk of lymphoma, its protective effect among Chinese children is likely modest in magnitude and concentrated in certain subgroups defined by length of breastfeeding, age at diagnosis and histological subtype of cancer.

Familial clustering of breast and prostate cancers and risk of postmenopausal breast cancer

BACKGROUND

Previous studies have suggested that cancers of the breast and prostate cluster in families and that the presence of both diseases in a family may be associated with increased risk of breast cancer.

PURPOSE

Our purpose was to evaluate whether 1) prostate cancer aggregates in families with postmenopausal breast cancer, 2) families with cancers of the breast and prostate are the same ones as families with cancers of the breast and ovary, and 3) a family history of prostate cancer is associated with increased risk of postmenopausal breast cancer.

METHODS

We analyzed data from a large prospective cohort study of Iowa women that were (at baseline) aged 55-69 years in 1986. At the third follow-up survey in 1992, self-reported data on family history of breast, ovarian, and prostate cancers in parents and siblings were provided by 30,883 women. Additional information was collected to ascertain whether the age-of-onset of breast cancer in mothers or sisters was before or after the age of 45 years. Cancer occurrence was documented using the State Health Registry of Iowa.

RESULTS

History of prostate cancer in their father or a brother was reported by 3384 (11.0%) of the women, and a total of 4090 women (13.2%) reported breast cancer in their mother or a sister. A positive family history of both cancers was reported by 556 women, significantly (two-sided P < .001) greater than the 457 women expected if the family histories were independent. The aggregation of breast, prostate, and ovarian cancers was reported by 22 participants, greater than the 2.7 expected (two-sided P < .0001). During 6 years of follow-up, 578 breast cancers were identified in the cohort at risk. Compared with women without a family history of either cancer, women with a family history of breast cancer had a relative risk (RR) of 1.37 (95% confidence interval [CI] = 1.06-1.79) if the affected relative had onset after the age of 45 years, and an RR of 1.71 (95% CI = 1.13-2.61) if the affected relative had onset at or before the age of 45. A family history of prostate cancer in the absence of a family history of breast cancer was associated with an RR of 1.19 (95% CI = .90-1.56). However, a family history of both breast and prostate cancers was associated with RRs of 2.06 (95% CI = 1.23-3.45) and 2.35 (95% CI = .97-5.67) for breast cancer onset in relatives of greater than 45 and less than or equal to 45 years, respectively.

CONCLUSIONS

These observations are concordant with recent reports that suggest a shared familial risk (inherited or environmental) for these hormone-dependent malignancies.

In vivo actions of a gonadotropin-releasing hormone (GnRH) antagonist on gonadotropin-II and growth hormone secretion in goldfish, Carassius auratus

In our previous in vitro studies, [Ac-delta 3-Pro1, 4FD-Phe2, D-Trp3,6]-mGnRH (analog E) suppressed both gonadotropin-II (GTH-II) and growth hormone (GH) release stimulated by sGnRH and cGnRH-II. In the present study analog E significantly inhibited the increases in plasma GTH-II levels stimulated by sGnRH in sexually mature female and sexually recrudescent goldfish. Treatment of goldfish with alpha-methyl-p-tyrosin methyl ester (alpha-MPT) inhibits dopamine synthesis and abolishes the inhibitory actions of dopamine on GTH-II release, resulting in a potentiation of the GTH-II response to sGnRH. Following alpha-MPT pretreatment, analog E significantly reduced basal plasma GTH-II levels, and suppressed both sGnRH and cGnRH-II actions on GTH-II release. Analog E also inhibited the increase in plasma GTH-II levels in sexually mature male goldfish exposed to the female sexual pheromone, 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha 20 beta-P), demonstrating that the increase in plasma GTH-II levels is due to release of endogenous GnRH. Analog E significantly inhibited the increases in plasma GH levels stimulated by treatment with sGnRH. Implantation of estradiol pellets increases basal plasma GH levels and increases the GH responsiveness to sGnRH in sexually recrudescent goldfish; analog E also suppressed the increase in plasma GH levels stimulated by injection of sGnRH in estradiol-treated fish. Analog E suppressed basal GTH-II and GH levels in fish that were unhandled prior to injection; however, analog E was not effective in reducing basal plasma GTH-II or GH levels in experiments in which the fish were blood sampled or subjected to some experimental manipulation prior to injection of analog E. Analog E also suppressed basal levels of GTH-II in alpha-MPT-treated fish, suggesting that stress inhibition of GTH-II release may be mediated by the dopaminergic system. In summary, the results demonstrate that (i) analog E can suppress the actions of exogenous sGnRH and cGnRH-II on GTH-II and GH release in vivo, (ii) the GnRH system mediates, at least in part, the plasma GTH-II response in sexually mature male goldfish following exposure to the female sexual pheromone 17 alpha 20 beta-P, and (iii) endogenous GnRH peptides are important in the regulation of basal plasma levels of GTH-II as well as GH, particularly in low stress conditions.

Tissue distribution and elimination of indium in male Fischer 344 rats following oral and intratracheal administration of indium phosphide

The use of indium phosphide (InP) in the semiconductor industry has raised concerns about potential occupational exposure. The tissue distribution and elimination of indium were investigated in adult male Fischer 344 rats following either a single or 14 consecutive daily oral doses, or following an intratracheal instillation of InP (10 mg/kg). The concentrations of indium ions in blood, urine, feces, and tissues were quantified either using direct acid digestion followed by electrothermal atomic absorption spectrophotometry (ET-AAS) or using an extraction method with methyltricapryl ammonium ions to remove indium from the matrix followed by ET-AAS. Indium was poorly absorbed from the gastrointestinal tract in both single and multiple oral dose studies. Upon its absorption, indium was relatively evenly distributed among the major organs such as liver, kidney, lung, spleen, and testes. By 96 h after oral dose treatment, less than 0.11% of the dose of indium was recovered from tissues in the single- or multiple-dose experiment. At 96 h, retention of indium in the body was about 0.36% of the dose (except for lung) following intratracheal instillation of InP. Following oral dose administration, the majority of indium was recovered from the gastrointestinal tract and its contents. The high recovery of indium (73% of the dose) in the feces after intratracheal instillation presumably reflects mucociliary clearance and/or biliary excretion of indium. Urinary indium accounted only for 0.08-0.23% of the dose during a 240-h collection period in both single- and multiple-dose studies. It seems that fecal excretion serves as the major route for indium elimination, and this results from poor absorption. Because of the poor absorption of indium following multiple oral doses or intratracheal instillation of InP, it seems unlikely that indium will accumulate in the body following InP exposure.

Transposon-induced mutants of Listeria monocytogenes incapable of growth at low temperature (4 degrees C)

Transposon mutagenesis was used to pursue the molecular basis of cold resistance in Listeria and its possible involvement in pathogenesis. We have generated transposon-induced mutants of Listeria monocytogenes which were unable to grow at 4 degrees C but grew at 8 degrees C, 22 degrees C and 37 degrees C. The transposon was localized in the same 1.8-kb EcoRI fragment in two independently derived mutants. Mutants which carried single transposon insertions had normal hemolytic activity, motility and invasion of cultured fibroblasts. These results indicate that in L. monocytogenes cold sensitivity can be single transposon insertions and that loss of cold resistance may not interfere with other phenotypes, including invasion in a cell culture model.

[A controlled study of chemiluminescent enzyme immunoassay for the measurement of estrogen receptor in tissue of gynecological neoplasms]

In this study, chemiluminescent enzyme immunoassay (CLEIA) has been developed for the measurement of estrogen receptor (ER) in 34 gynecological oncological tissues from 15 cases of endometrial carcinoma, 15 cases of ovarian tumors and 4 cases of other gynecological tumors. The accuracy, specificity and sensitivity of CLEIA for ER were compared with that of dextran-coated charcoal (DCC) and enzyme immunoassay (EIA).

RESULTS

(1) the standard curve of ER-CLEIA showed a significant linear correlation between the luminosity and ER concentration (r = 0.9786, P < 0.001); (2) The results of CLEIA and that of the other two methods were compared; the correlation coefficients were > 0.8 and their corresponding rates were > 90%; (3) the positive rate of ER determined by these three methods showed no significant differences, however, the mean value of ER-CLEIA was the highest among them. It is concluded that the CLEIA has a higher sensitivity than that of the other two methods for the measurement of ER.

Dietary cholesterol, fat, and lung cancer incidence among older women: the Iowa Women's Health Study (United States)

To test the hypothesis that a high intake of dietary cholesterol and fat is associated with elevated risks of lung cancer, we analyzed data from a population-based, prospective, cohort study conducted among 41,837 postmenopausal Iowa (United States) women who completed, in 1986, a comprehensive mailed questionnaire including information on usual intake of 127 food items. All cohort members were followed for cancer incidence through the statewide cancer registry. By 1991, after six years of follow-up, 272 incident lung-cancer cases were identified. After controlling for total energy intake and other confounding factors, dietary cholesterol, total fat, and animal fat were unrelated to lung cancer risk. Intake in the upper three quartiles of plant-derived fat, however, was related to a 30 to 40 percent lower incidence of lung cancer, comparative with those in the lowest quartile, with more pronounced reduction in risk observed among smokers (relative risk = 0.6, 95 percent confidence interval = 0.4-0.9). This prospective cohort study suggests that high intake of fat of plant origin may be associated with reduced risk of lung cancer, while dietary cholesterol and animal fat intake is unrelated to the etiology of this malignancy in postmenopausal women.

Diagnostic X-ray and ultrasound exposure and risk of childhood cancer

In a population-based case-control study of 642 childhood cancer cases and the same number of matched controls in Shanghai, China, we evaluated the relationship between diagnostic X-ray (preconception, pre- and post-natal) and antenatal ultrasound exposure and the subsequent risk of developing three major types of childhood cancer (acute leukaemia, lymphoma and brain tumours) and all childhood neoplasms combined. Consistent with previous studies, prenatal X-ray exposure was found to be associated with an 80% increased risk of childhood cancers, although the estimation was based on 4% and 2% exposed cases and controls and was only marginally statistically significant (P = 0.08). Post-natal X-ray exposure was also linked with a small elevation in the risk of all cancers and the major categories of malignancies in children. Little evidence, however, was found to relate parental preconception X-ray exposure with the subsequent cancer risk in offspring, regardless of the exposure window and the anatomical site of X-ray exposures. This study adds further to the growing literature indicating that antenatal ultrasound exposure is probably not associated with an increased risk of childhood cancer.

[Expression of cDNA RA538 induces terminal differentiation and apoptosis of its parental malignant cell line in vitro]

A full-length cDNA (RA538) was isolated from human esophageal cancer cell line EC8712 after retinoic acid treatment. An expression vector of this cDNA (pRA538) was cotransfected with the neo gene (pDORneo) into parental cancer cell line EC8712. The cell colonies obtained after selection in G418-containing culture medium showed very poor growth, reduced (by 68%-76%) 3H-TdR uptake and morphological changes characteristic of terminal differentiation and programmed cell death (apoptosis). In situ hybridization with RA538 probes revealed expression of mRNA of RA538 in the cytoplasm of the transfected cells. The cells transfected solely with pDORneo after G418 selection showed normal growth pattern and no RA538 expression. However, none of the control cells EC8712 survived the G418 selection. Thus the expression of cDNA RA538 has a similar effect on the esophageal cancer cell EC8712 as the retinoic acid does.

Diet, serum markers and breast cancer mortality in China

This county-based correlation study examined associations of breast cancer mortality with dietary habits and certain serum biochemical markers, utilizing data collected from an ecological survey in 65 Chinese rural counties. Univariate correlation and multivariate regression analysis showed that consumption of animal foods, including eggs, fish and meat, was positively linked to county-wide mortality rates of breast cancer in Chinese women. No clear associations between breast cancer mortality rates and consumption of green vegetables, carrots and fruits were observed in this study. A modest inverse correlation between serum vitamin C levels and breast cancer mortality was observed, while selenium levels were positively related to the mortality rates. Positive correlations for serum ferritin and hemoglobin were found, in agreement with recent reports of an elevated cancer risk with increased body iron stores. Limitations of these ecological data preclude causal inferences, but the findings provide clues to breast cancer risk and protective factors in a low incidence area of the world.

A nested case-control study of oesophageal and stomach cancers in the Linxian nutrition intervention trial

BACKGROUND

Rates of oesophageal/gastric cardia cancer in Linxian, a rural county in north central China, are among the world's highest, but the risk factors are not well understood.

METHODS

A nested case-control study of oesophageal and stomach cancers was conducted within a cohort of 29,584 adults who participated in a randomized nutrition intervention trial. Information on participant characteristics collected during interviews before the trial began was compared between individuals who subsequently developed cancers of the oesophagus (N = 640) or stomach (N = 539), mainly cardia, and individually matched controls (control/case ratio = 5). Analyses were performed separately for oesophageal and stomach cancers using conditional logistic regression.

RESULTS

For oesophageal cancer, tobacco smoking was associated with a significantly elevated risk, with a twofold increase among long-term smokers. Alcohol consumption was uncommon and not related to risk. High consumption of eggs or fresh vegetables was associated with 20% reductions in risk, and risk significantly declined as pre-trial body mass index (BMI), an indicator of long-term nutritional status, increased. No increases in risk were associated with intake of pickled vegetables or mouldy foods, although consumption levels at the start of the trial were low. Excess risks of 40-80% were found among individuals who had reported a history of cancer, notably of the oesophagus and stomach, in parents or sibs. For stomach cancer, only low BMI was significantly associated with elevated risk.

CONCLUSIONS

This study indicates that several risk factors for oesophageal and stomach cancers in Linxian, including smoking, nutritional deficiency, and familial cancer occurrence, resemble those in other areas of the world and contribute partly to the remarkably elevated rates in this area of China.

Occupation, physical activity, and risk of prostate cancer in Shanghai, People's Republic of China

Based on occupational data for all (n = 264) prostate cancer cases diagnosed during 1980-84 in urban Shanghai and on employment information from the 1982 census, standardized incidence ratios (SIR) were calculated for occupational groups classified by job type and physical activity level. White-collar workers (professionals, government officials, clerical workers, salespersons) had an elevated incidence of prostate cancer, although the excesses were not significant. In addition, when jobs were classified by time spent sitting or energy expenditure, men employed in occupations with low physical activity levels tended to have moderately elevated risks of prostate cancer. Findings from this study in an area with one of the world's lowest incidence rates of prostate cancer add to the accumulating evidence that jobs with a low level of physical activity are associated with an increased prostate-cancer risk.

Current status of lung cancer diagnosis and treatment in Shanghai

The status of diagnosis and treatment of lung cancers discovered during 1 year in the Shanghai population are presented. A total of 940 lung cancers was detected from inhabitants of 35-64 years of age, with a male/female ratio of 1.8:1. Pathology showed 35.7% adenocarcinoma and 35.1% squamous cell carcinoma. There was a predominance of adenocarcinoma (47.6%) in females and of squamous cell carcinoma (44.6%) in males. Most (68.6%) of the lesions detected were already advanced in contrast to 14.7% of Stage I disease. The need for vigilance on the part of doctors was demonstrated by the fact that 23.3% of patients were seen by the doctor within 1 month after presenting with symptoms and 44.5% of them had their diagnosis suspected within 1 month after their first hospital visit. The treatment consisted of surgery for 33.3%, chemotherapy for 35%, traditional Chinese medicine for 20% and symptomatic management for 9.6% of patients. As only 55.8% Stage I patients were treated by surgery, the treatment protocol seemed to be improperly biased. The adequate training of health workers was shown by the fact that 79.7% of these patients were confirmed by pathology and/or cytology and most of the Stage I lesions were diagnosed outside the hospital.

Risk factors for cancers of the nasal cavity and paranasal sinuses among white men in the United States

A case-control analysis of cancer of the nasal cavity and sinuses was performed using data from the 1986 National Mortality Followback Survey. Data on cigarette smoking, alcohol consumption, usual diet, and other factors from 147 white men who died from nasal cancer and from 449 controls who died from other causes were compared. Cigarette smoking was related to an increased risk of nasal cancer, with a doubling of risk among heavy or long-term smokers and a reduction in risk among long-term quitters. Among nonsmokers, having a spouse who smoked was associated with a significantly elevated risk of nasal cancer. After adjustment for smoking, a significant dose-response relation was also noted between alcohol drinking and risk of nasal cancer. High consumption of salted/smoked foods was associated with elevated risk, and risk tended to decrease with increasing intake of vegetables. Associations were more pronounced for cigarette smoking and certain dietary items when the analysis was restricted to maxillary sinus cancer. The study confirms that cigarette smoking is a risk factor for nasal cancer, and provides further evidence that dietary factors may play a role in the etiology of this malignancy.

Declining incidence is greater for esophageal than gastric cancer in Shanghai, People's Republic of China

Temporal trends in the incidence of esophageal and gastric cancers during 1972 to 1989 were addressed in urban Shanghai, the location of China's longest standing cancer registry. Over the 18 year study period, esophageal cancer rates decreased more than 50% from 28.8/100,000 person-years in 1972-74 to 13.3/100,000 in 1987-89 among men and from 11.3/100,000 to 5.4/100,000 among women. Reductions were apparent in each age group, but most pronounced among younger generations, with more than a 75% decline in incidence among those under age 55 years. The incidence rate for stomach cancer among men decreased 20% from 62.0/100,000 in 1972-74 to 50.1/100,000 in 1987-89. The reduction among women, however, was minor, from 23.9/100,000 to 23.2/100,000. The patterns varied by age, with declines among persons 45-64 years and increases among those in older and younger age groups. The determinants of these trends are not clear, but appear related in part to dietary changes.

Toxicokinetics of sulfasalazine (salicylazosulfapyridine) and its metabolites in B6C3F1 mice

The toxicokinetics of salicylazosulfapyridine (SASP) and its metabolites were investigated in male and female B6C3F1 mice either following single intravenous (5 mg/kg) or oral (67.5, 675, 1350, and 2700 mg/kg) doses, or following three consecutive daily oral doses (675, 1350, and 2700 mg/kg). Plasma concentrations of SASP and its metabolites were quantified by HPLC. Upon intravenous administration, SASP rapidly disappeared from blood with a mean residence time of 0.45-0.78 hr. The only metabolite of SASP found in plasma after an intravenous dose was sulfapyridine (SP). In both sexes, the absolute oral bioavailability of SASP ranged between 16.6-18.2% at a dose of 67.5 mg/kg, and between 2.6-8.7% at doses of 675-2700 mg/kg. Following oral administration of SASP, both SP and AcSP were identified in plasma. The area under the plasma concentration-time curves (AUC) of SP at all four oral doses were approximately 21- to 32-fold or 5- to 25-fold greater than those of SASP in male or female mice, respectively. The acetylated form of SP and AcSP, produced AUC values higher than SASP but much less than SP. Multiple oral doses with SASP did not alter the temporal patterns of SASP absorption and elimination in comparison to a single dose. However, SP accumulated in both sexes following multiple oral doses. A gender-dependent difference in toxicokinetic profiles for SASP and SP was also observed. Female mice displayed a higher Cmax of SASP and SP than did male mice. Although the volume of distribution of SASP was similar in both sexes, the systemic clearance of SASP in males was about twice that observed in females.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous versus intermittent nitroglycerin administration in experimental heart failure: vascular relaxation and radioligand binding to adrenoceptors and ion channels

Continuous nitroglycerin (NTG) administration causes pharmacologic tolerance in humans and animals, whereas intermittent dosing is capable of avoiding or reducing tolerance development. The mechanism of NTG-induced hemodynamic tolerance may involve specific vascular desensitization and/or neurohormonal compensation. We compared effects of long-term (10 days) NTG administration (continuous or intermittent 12 h on/12 h off transdermal dosing, 10 micrograms/min) to rats with congestive heart failure (CHF) on radioligand binding from selected tissues. Tension responses in isolated blood vessels, plasma renin activity (PRA), plasma Na+ and K+ concentrations were also determined. The maximal binding values (Bmax) for [3H]glyburide and [3H]PN 200 110 in homogenates of left ventricle, right ventricle, and brain were not significantly different after NTG administration (continuous or intermittent), as compared with control. Intermittent, but not continuous, NTG caused significant increases in beta-adrenoceptor densities in the left ventricle, as judged by [3H]dihydroalprenolol binding (Bmax values: intermittent NTG 34.5 +/- 4.8, continuous NTG 24.4 +/- 2.6, placebo control 20.9 +/- 2.9 fmol/mg protein); Kd values for all ligands were not significantly altered by NTG administration. Both intermittent and continuous NTG increased the vascular contractile response to phenylephrine in isolated rat thoracic aorta. Slight reductions (two- to four-fold shifts in EC50 values) in thoracic aorta relaxant response to NTG were observed in both treatment groups as compared with control. Intermittent and continuous NTG administration caused selective changes in beta-adrenoceptor density and vascular response. These changes may contribute partly to the phenomenon of pharmacologic tolerance after chronic nitrate administration.

A cohort study of smoking, alcohol consumption, and dietary factors for pancreatic cancer (United States)

Risk factors for pancreatic cancer were evaluated in a cohort study of 17,633 White men in the United States who responded to a mailed questionnaire in 1966 and were followed-up through 1986 for mortality. Cigarette smoking and alcohol consumption were found to be important risk factors for pancreatic cancer. Risks increased significantly with number of cigarettes smoked, reaching fourfold for smokers of 25 or more cigarettes per day relative to nonsmokers. Alcohol intake also was related significantly to risk, with consumers of 10 or more drinks per month having three times the risk of nondrinkers, but dose-response trends among drinkers were not smooth. Coffee consumption was unrelated to risk. Dietary analyses revealed a rising rate of pancreatic cancer mortality with increasing consumption of meat after adjustment for other risk factors. Men in the highest quartile of meat intake had about three times the risk of those in the lowest quartile. No consistent association, however, was observed for consumption of fruits, vegetables, or grains. This study confirms cigarette smoking as an important risk factor for pancreatic cancer, and provides evidence that elevated intake of alcohol and meat may increase the risk of this fatal malignancy.

Occupational risks for primary liver cancer in Shanghai, China

Using occupational data for over 3,400 primary liver cancer cases diagnosed between 1980 and 1984 reported to the Shanghai Cancer Registry, and employment information from the 1982 census for the Shanghai population, standardized incidence ratios were computed to generate leads to occupational risks of liver cancer. Among men, a statistically significant excess number of cases was observed for chemical processors, textile workers, wood workers, blacksmiths and machine-tool operators, and material handlers and dock workers. Increased incidence of liver cancer also was observed among female transport equipment operators. These findings indicate that a number of similar occupations are associated with increased risk of primary liver cancer in western countries and China. Although causal inferences cannot be drawn from these data, our study adds to the limited evidence of the potential role of occupational exposures in liver carcinogenesis.

Prior medical conditions and the risk of adult leukemia in Shanghai, People's Republic of China

A population-based case-control interview study of 486 adult leukemia cases and 502 healthy controls was carried out in Shanghai, People's Republic of China during 1987-89 to evaluate the etiologic role of prior medical conditions, medications, and diagnostic X-rays. Risks were examined separately for 236 cases with acute non-lymphocytic leukemia (ANLL), 79 with chronic myeloid leukemia (CML), 81 with acute lymphocytic leukemia (ALL), and 21 with chronic lymphocytic leukemia (CLL). Little difference was found between cases and controls for prior history of diabetes, hypertension, allergic conditions, most medications, and diagnostic X-rays. A few significant associations were observed for appendectomy, tuberculosis, and for several other chronic disorders with specific leukemia cell types, but the odds ratio estimates for most of these ranged from two to three and, with the exception of the two specified above, were based generally on five or fewer exposed controls. In contrast to an association with childhood leukemia in Shanghai, prior use of chloramphenicol was not linked with ANLL or other forms of adult leukemia. Further research is needed to clarify the relation of specific medical conditions and exposures with particular subtypes of leukemia, and to examine reasons for the low incidence of CLL in China and other Asian populations.

Physical activity and risk of endometrial cancer

In a population-based case-control study of endometrial cancer, we interviewed 268 cases and an equal number of matched controls regarding physical activity at work and outside of work. We also obtained self-ratings of overall physical activity levels. The results showed that nonretired women holding sedentary jobs or those reporting sedentary life-styles were at somewhat increased risk of endometrial cancer. The associations remained unchanged after adjustment for caloric intake and body mass index. Although an effect of physical inactivity on endometrial cancer risk is biologically plausible, our results show some inconsistencies, such as a lack of elevation in risk among women who were physically inactive outside of work.

Incidence trends for cancers of the breast, ovary, and corpus uteri in urban Shanghai, 1972-89

Incidence data from the Shanghai (People's Republic of China) Cancer Registry were used to assess the temporal trends of three major female cancers during 1972-89. Rates for cancers of the breast, corpus uteri and, to a lesser extent, ovary rose over the study period. The increases in breast and ovarian cancer were most pronounced among women under age 50, whereas those for corpus uteri cancer were restricted generally to those aged 55 to 69 years. When considered by cohort year of birth, risk of breast and ovarian cancers rose among women born since 1925 and 1935, respectively, but little evidence of cohort effect was apparent for corpus uteri cancer. Potential explanations for these patterns are explored.

Occupational physical activity and the incidence of cancer of the breast, corpus uteri, and ovary in Shanghai

BACKGROUND

A sedentary life style has been consistently associated with an increased risk of colon cancer, but the evidence for its association with breast and other gynecologic cancers is limited.

METHODS

Occupational information for 3783 incident patients with cancer (breast, 2736; corpus uteri, 452; and ovary, 595) whose disease was diagnosed during the period 1980-1984 was compared with 1982 census data on employment in Shanghai urban areas. The standardized incidence ratios (SIR) of these cancers were estimated for each occupational group classified by job titles and physical activity levels.

RESULTS

A significantly increased incidence of breast cancer was found among professionals (SIR = 158), government officials (SIR = 131), and clerical workers (SIR = 143); the incidence was reduced among service workers (SIR = 87) and craftsmen (SIR = 91). Occupational physical activity, as measured by sitting time and energy expenditure, was inversely related to breast cancer incidence, with SIR of 127-131 for inactive jobs (sedentary or low-energy expenditure) and 79-93 for active jobs (long periods of standing or high energy expenditure). Similar associations, although to a lesser extent, were also seen for cancer of the corpus uteri and ovary.

CONCLUSIONS

Women with low physical activity occupations had an increased incidence of cancer of the breast, corpus uteri, and ovary; the incidence was reduced among women with high-activity jobs. These findings were consistent with observations from earlier studies and provided further evidence that physical activity may lower the risk of these female hormone-dependent cancers.