DNA synthesis by ovine mammary alveolar epithelial cells: effects of heparin, epidermal growth factor-related peptides and interaction with stage of pregnancy

Amphiregulin is a heparin-binding member of the epidermal growth factor (EGF) family, which we have recently shown to be expressed in sheep mammary gland. Uniquely among known EGF-like growth factors, its mitogenic activity is inhibited by soluble heparin, but heparin-like molecules on the cell surface and/or in extracellular matrix appear to be necessary for amphiregulin to exert its biological effect. In primary cultures of sheep mammary alveolar epithelial cells, heparin (1-20 mg/l) inhibited DNA synthesis in a dose-dependent manner. The extent of the inhibition was influenced by physiological state, being greater (P < 0.05) in mammary cell cultures derived from 5- to 10-week pregnant sheep (63.1 +/- 8.2%, mean +/- S.E.M., n = 8) than in cultures derived from sheep which were non-pregnant (35.8 +/- 8.3% inhibition, n = 6) or late, 20-week, pregnant (39.8 +/- 5.6%, n = 6). Both EGF and transforming growth factor-alpha (TGF-alpha) significantly (P < 0.001) increased DNA synthesis in the presence of heparin. The effect of TGF-alpha was dose-related, wholly reversing the inhibitory effect of heparin in cell cultures from non-pregnant and 20-week pregnant sheep. DNA synthesis was stimulated by amphiregulin and TGF-alpha increased the maximum response. The heparin antagonist, hexadimethrine, inhibited DNA synthesis, but, in the presence of amphiregulin, approximately equivalent concentrations of heparin overcame this inhibitory effect. In the presence of heparin, TGF-alpha showed synergistic interactions with insulin or IGF-I. The results indicate interactive effects of EGF and IGF growth factor families in sheep mammary growth.

A role for oestrogens in the male reproductive system

Oestrogen is considered to be the 'female' hormone, whereas testosterone is considered the 'male' hormone. However, both hormones are present in both sexes. Thus sexual distinctions are not qualitative differences, but rather result from quantitative divergence in hormone concentrations and differential expressions of steroid hormone receptors. In males, oestrogen is present in low concentrations in blood, but can be extraordinarily high in semen, and as high as 250 pg ml(-1) in rete testis fluids, which is higher than serum oestradiol in the female. It is well known that male reproductive tissues express oestrogen receptors, but the role of oestrogen in male reproduction has remained unclear. Here we provide evidence of a physiological role for oestrogen in male reproductive organs. We show that oestrogen regulates the reabsorption of luminal fluid in the head of the epididymis. Disruption of this essential function causes sperm to enter the epididymis diluted, rather than concentrated, resulting in infertility. This finding raises further concern over the potential direct effects of environmental oestrogens on male reproduction and reported declines in human sperm counts.

Rotavirus nonstructural glycoprotein NSP4 alters plasma membrane permeability in mammalian cells

The endoplasmic reticulum-localized transmembrane glycoprotein NSP4 of rotavirus is a key protein involved in rotavirus cytopathology. We have used a dual-recombinant vaccinia virus system to express NSP4 in monkey kidney epithelial cells at a level comparable to that observed during rotavirus infection. Expression of NSP4 results in loss of plasma membrane integrity, which can be demonstrated by release of both 51Cr and lactate dehydrogenase into the medium. The cytotoxic behavior of NSP4 is dose dependent, and morphological analysis reveals gross changes to cell ultrastructure, indicative of cell death. Thus, intracellular expression of a single rotavirus protein which localizes to the endoplasmic reticulum membrane has profound effects on the stability of the plasma membrane and cell viability. Analysis of NSP4 deletion mutants indicates that a membrane-proximal region located within the cytoplasmic domain may mediate cytotoxicity.

Estrogenic responses in estrogen receptor-alpha deficient mice reveal a distinct estrogen signaling pathway

Estrogens are thought to regulate female reproductive functions by altering gene transcription in target organs primarily via the nuclear estrogen receptor-alpha (ER-alpha). By using ER-alpha "knock-out" (ERKO) mice, we demonstrate herein that a catecholestrogen, 4-hydroxyestradiol-17beta (4-OH-E2), and an environmental estrogen, chlordecone (kepone), up-regulate the uterine expression of an estrogen-responsive gene, lactoferrin (LF), independent of ER-alpha. A primary estrogen, estradiol-17beta (E2), did not induce this LF response. An estrogen receptor antagonist, ICI-182,780, or E2 failed to inhibit uterine LF gene expression induced by 4-OH-E2 or kepone in ERKO mice, which suggests that this estrogen signaling pathway is independent of both ER-alpha and the recently cloned ER-beta. 4-OH-E2, but not E2, also stimulated increases in uterine water imbibition and macromolecule uptake in ovariectomized ERKO mice. The results strongly imply the presence of a distinct estrogen-signaling pathway in the mouse uterus that mediates the effects of both physiological and environmental estrogens. This estrogen response pathway will have profound implications for our understanding of the physiology and pathophysiology of female sex steroid hormone actions in target organs.

Myeloperoxidase genetic polymorphism and lung cancer risk

Myeloperoxidase is a lysosomal enzyme found in high concentrations in human lung due to recruitment of neutrophils. Myeloperoxidase activates benzo[a]pyrene as well as aromatic amines in tobacco smoke and generates carcinogen-free radicals. A single base substitution (G to A) in the promoter region of the myeloperoxidase gene has recently been demonstrated to markedly reduce transcription. We developed an RFLP/PCR assay to test the hypothesis that the allele favoring lower transcription (A allele) reduces the risk of lung cancer. Among population controls, 7.8% of 459 Caucasians and 9.4% of 244 African-Americans inherited two copies of the A allele. Caucasians with the A/A genotype were at 70% reduced risk of lung cancer (odds ratio, 0.30; 95% confidence interval, 0.10-0.93; P = 0.04; 182 cases). A lesser reduction in risk was observed for African-Americans with this genotype (odds ratio, 0.61; 95% confidence interval, 0.26-1.41; 157 cases). Individuals who inherit two copies of an allele that reduces transcription of the myeloperoxidase gene may be at decreased risk of lung cancer.

Methodological issues in the use of tumour markers in cancer epidemiology

In this chapter, we review major methodological and practical issues associated with the use of tumour markers. At this stage of development, studies with a combination of tumour, susceptibility and exposure markers are needed to illustrate the link between exposure and biological response and to assess the interactive effects of tumour susceptibility markers in this process. Several practical issues related to the application of tumour markers are discussed, including banking of tumour tissue, setting a laboratory strategy and performing etiological heterogeneity analysis.

Elucidation of a role for stromal steroid hormone receptors in mammary gland growth and development using tissue recombinants

The use of tissue recombinants in conjunction with steroid receptor deficient mice is described as a tool to dissect the complex paracrine pathways of sex-hormone-regulated epithelial growth and ductal morphogenesis in the mammary gland and other hormone target organs. The basic methodology involves the construction of the four possible tissue recombinants composed of epithelium (E) and stroma (S) from wild-type (wt) and knock-out (KO) mice: wt-S + wt-S, wt-S + KO-E, KO-S + KO-E, and KO-S + wt-E. All tissue recombinants are grown as subrenal capsule grafts in nude mice. Following appropriate hormonal challenge epithelial growth can be studied in the four types of tissue recombinants. Such studies using estrogen receptor, androgen receptor and progesterone receptor knockout mice demonstrate that epithelial steroid receptors are neither necessary nor sufficient for hormonal regulation of epithelial proliferation. Instead, hormonal regulation of epithelial proliferation is a paracrine event mediated by hormone-receptor-positive stromal cells.

Health care utilization and health status in high-risk children randomized to receive group or individual well child care

OBJECTIVE

To determine if health care utilization and health status among high-risk children is modified by the use of group well child care (GWCC) as compared with traditional one-to-one individual well child care (IWCC).

STUDY DESIGN

Randomized controlled trial.

PARTICIPANTS

Children less than 4 months old from families with at least one of the following maternal risk factors: poverty, single marital status, age <20 years at delivery, less than a high school education, previous substance abuse, or history of abuse as a child.

SETTING

Two urban, university pediatric clinics in Seattle, Washington.

INTERVENTIONS

Children were randomized to receive GWCC or IWCC at the time of enrollment. Health supervision visits with two study nurse practitioners were scheduled at 4, 5, 6, 8, 10, 12, and 15 months of age. GWCC study visits consisted of a group discussion of age-appropriate child-rearing issues, along with a physical examination, health screening, and immunizations. Health care utilization among children receiving GWCC and those randomized to IWCC was assessed using the following measures: compliance with study visits, compliance with any age-appropriate health supervision visit, emergency department utilization, and immunization rates (defined as the proportion of children in each group who had received all recommended vaccines by 1 year of age). Provider time for GWCC and IWCC study visits was also recorded. Health status was measured using Stein's Functional Status IIR, completed by the mothers of study patients when their children completed the study at 15 months of age.

RESULTS

A total of 106 children received GWCC, whereas 104 were randomized to IWCC. Compliance with scheduled study visits was 47% for GWCC patients and 54% for IWCC recipients; overall compliance with any age-appropriate health supervision visit was 68% and 66%, respectively. Provider time was similar for GWCC and IWCC visits. By the age of 1 year, 67% of GWCC recipients and 73% of those receiving IWCC had received three DTP/DT, three OPV/IPV, three Hib, and three hepatitis B immunizations. A total of 242 emergency department visits were made by study patients during their enrollment in the project; there was no difference in the average number of visits between GWCC or IWCC children. However, children receiving IWCC were more likely to have at least one emergency department visit than GWCC recipients. At the conclusion of the project, health status, as measured by the Functional Status IIR, was similar in GWCC and IWCC patients (mean scores 92.4 +/- 1.4 and 92.5 +/- 1.1, respectively).

CONCLUSIONS

Health care utilization and health status was similar in high-risk children whether they received GWCC or IWCC. GWCC is a viable format for health supervision visits in this population.

A randomized trial of a consultation service to reduce falls in nursing homes

CONTEXT

Falls are a major health problem in nursing homes, but no interventions have been shown to prevent falls in nursing home residents.

OBJECTIVE

To evaluate an intervention program designed to prevent falls and associated injuries in high-risk nursing home residents.

DESIGN

Randomized controlled trial.

SETTING AND PARTICIPANTS

Seven pairs of middle Tennessee nursing homes with 1 facility in each pair randomly assigned to the intervention. Facilities had 482 (261 control, 221 intervention) residents who qualified for the study because they had high risk of falls and a potential safety problem that could be addressed by the intervention.

INTERVENTION

Comprehensive structured individual assessment with specific safety recommendations that targeted suboptimal practices for environmental and personal safety, wheelchair use, psychotropic drug use, and transferring and ambulation. Facility staff were encouraged to implement the individual recommendations and to improve overall facility safety.

MAIN OUTCOME MEASURES

The mean proportion of recurrent fallers and incidence rate of injurious falls in the facility in the year following the intervention.

RESULTS

The mean proportion of recurrent fallers in intervention facilities (43.8%) was 19.1% (95% confidence interval, 2.4%-35.8%) lower than that in control facilities (54.1%, P=.03). Intervention facilities had a nonsignificant trend toward a lower mean rate of injurious falls (13.7 vs 19.9 per 100 person-years, reduction of 31.2%, P=.22). Subgroup analyses suggested greatest benefits for residents for whom the recommended interventions were carried out or who had 3 or more falls in the preceding year.

CONCLUSION

The high rate of falls and related injuries in nursing homes should not be viewed as inevitable, but as outcomes that can be substantially improved through structured safety programs.

Stability enhancement for peptide analysis by electrospray using the triple quadrupole mass spectrometer

Electrospray ionization sources, used with triple quadrupole mass spectrometers from PE/Sciex (API III+), Micromass (Quattro II), and Finnigan (TSQ 7000), were modified with a 35-gauge stainless steel needle. The dimensions of the needle were 63 microm i.d. by 145 microm o.d. with variable length, depending on the specific instrument. This modification led to enhanced signal stability, improved signal/noise ratios, and lowered sample consumption for a wide range of peptides. Stable baselines were observed with flow rates in the range of 50 nL/min to 5 microL/min. An alternative design, based on a metal wire housed within a fused silica capillary, led to the most stable signals of all during infusion, but caused excessive peak broadening with capillary chromatography. The Finnigan interface was further modified with an external postcolumn addition tee, used in conjunction with capillary liquid chromatography columns of 30 and 50 microm internal diameter. The best results with the modified Finnigan interface were acquired using the 50-microm column at a flow rate of 150 to 200 nL/min.

Estrogen receptor function as revealed by knockout studies: neuroendocrine and behavioral aspects

Estrogens are an important class of steroid hormones, involved in the development of brain, skeletal, and soft tissues. These hormones influence adult behaviors, endocrine state, and a host of other physiological functions. Given the recent cloning of a second estrogen receptor (ER) cDNA (the ER beta), work on alternate spliced forms of ER alpha, and the potential for membrane estrogen receptors, an animal with a null background for ER alpha function is invaluable for distinguishing biological responses of estrogens working via the ER alpha protein and those working via another ER protein. Data generated to date, and reviewed here, indicate that there are profound ramifications of the ER alpha disruption on behavior and neuroendocrine function. First, data on plasma levels of estradiol (E2), testosterone (T), and luteinizing hormone (LH) in wild-type (WT) versus ER alpha- mice confirm that ER alpha is essential in females for normal regulation of the hypothalamic-pituitary gonadal axis. Second, ovariectomized female ER alpha- mice do not display sexual receptivity when treated with a hormonal regime of estrogen and progesterone that induces receptivity in WT littermates. Finally, male sexual behaviors are disrupted in ER alpha- animals. Given decades of data on these topics our findings may seem self-evident. However, these data represent the most direct test currently possible of the specific role of the ER alpha protein on behavior and neuroendocrinology. The ER alpha- mouse can be used to ascertain the specific functions of ER alpha, to suggest functions for the other estrogen receptors, and to study indirect effects of ER alpha on behavior via actions on other receptors, neurotransmitters, and neuropeptides.

Chiropractic radiologists: a survey of chiropractors' attitudes and patterns of use

OBJECTIVE

To assess the chiropractic use of radiography, referral patterns to both medical and chiropractic radiologists and attitudes toward radiologists.

DESIGN

Random sample mail survey.

PARTICIPANTS

Practicing U.S. chiropractors.

RESULTS

The response rate was 46% (197 of 425). Seventy-four percent of the respondents have radiographic facilities in their offices. Contraindication screen (71%), pathological diagnosis (63%), biomechanics and posture (51%) and medicolegal protection (27%) were considered important reasons for taking radiographs. When chiropractors refer for radiographic services, 67% refer to medical radiologists and 17% to chiropractic radiologists. Eighty-five percent agreed that chiropractic radiologists are as well qualified as medical radiologists, but 36% thought that medical interpretation carried more legal authority than chiropractic interpretation. Seventy-six percent of respondents thought that the chiropractic radiologist should be consulted only for second opinions.

CONCLUSIONS

Most chiropractors obtain radiographs for clinical reasons, such as confirming a diagnosis of pathology, but many continue to use radiography as a screening tool and for medicolegal protection. Prevailing attitudes seem to indicate a need for this specialty in chiropractic, but the chiropractic radiological consultant is not widely used. The disparity between the perceived need for chiropractic radiologists and the current utilization patterns requires further research.

A randomized controlled trial of group versus individual well child care for high-risk children: maternal-child interaction and developmental outcomes

OBJECTIVE

To determine if group well child care (GWCC) for high-risk children affects maternal-child interaction and development as compared to these outcomes in children receiving traditional individual well child care (IWCC).

STUDY DESIGN

Randomized controlled trial.

PARTICIPANTS

Infants less than 4 months old at the initiation of the study who came from high-risk families. Families were classified as high risk, and eligible for study participation, if the mother had one or more of the following characteristics: poverty, single marital status, less than a high school education, age less than 20 years at delivery, previous substance abuse, or a history of abuse as a child.

SETTING

Two urban, university pediatric clinics in Seattle, Washington.

INTERVENTIONS

Study children were randomized to receive GWCC or IWCC prior to the first study visit at the age of 4 months. Study health supervision visits were scheduled at 4, 5, 6, 8, 10, 12, and 15 months of age. For children randomized to receive GWCC, study visits consisted of an age-matched group discussion of child rearing issues, either preceding or following a brief physical examination. After the 15-month visit, development of study patients was assessed by the use of Bayley Scales of Infant Development (Bayley). Maternal-child interaction and the home environment were evaluated by the use of the Nursing Child Assessment Teaching Scale (NCATS) and the Home Observation for Measurement of the Environment (HOME), respectively.

RESULTS

At least one outcome measure was obtained on 114 children; 86 patients completed all three outcome measures. Bayley psychomotor mean scores were 103.6 +/- 11.5 for GWCC patients versus 100.0 +/- 12.4 for those receiving IWCC (P = .14); mean scores for the mental section were 99.3 +/- 14.8 and 100.4 +/- 14.3, respectively (P = .71). The prevalence of high-risk maternal-child interactions was 10% in both the GWCC and IWCC groups. A high-risk home environment was found in 16% of IWCC patients versus 4% of those randomized to GWCC (odds ratio comparing IWCC to GWCC 4.6, 95% confidence interval 0.78, 26.0, after controlling for confounding variables). Provider time was similar among groups (mean number of minutes/patient/study visit: 19.8 +/- 5.6 and 20.4 +/- 6.7 for GWCC and IWCC, respectively, P = .66).

CONCLUSION

GWCC is a viable alternative to IWCC for high-risk children. Developmental outcomes and maternal-child interaction are at least as good for children who received GWCC as compared to traditional IWCC, without any increase in provider time required.

Is an antihistamine-decongestant combination effective in temporarily relieving symptoms of the common cold in preschool children?

OBJECTIVE

To determine whether an antihistamine-decongestant combination (ADC) is superior to placebo in temporarily relieving symptoms of upper respiratory tract infection (URI) in preschool children.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Four pediatric offices in the Seattle, Wash, area.

PARTICIPANTS

Children 6 months through 5 years of age with a URI of less than 7 days' duration.

METHODS

Children were randomly assigned to receive an ADC (brompheniramine maleate-phenylpropanolamine hydrochloride) or placebo as needed for URI symptoms. Two hours after each dose of study medication, changes in the child's runny nose, nasal congestion, cough, and sleep status were assessed by means of a standardized questionnaire.

RESULTS

A total of 175 responses were recorded for 59 patients. There were no statistically significant differences in symptom improvement between the ADC and the placebo group (runny nose, p = 0.48; nasal congestion, p = 0.94; cough, p = 0.66). However, the proportion of children asleep 2 hours after receiving the ADC was significantly higher than the proportion receiving placebo (46.6% vs 26.5%; p = 0.01). Results were unchanged after control for the correlated nature of repeated responses, age, symptom duration, use of acetaminophen, time that the medication was given, and parental desire for medication.

CONCLUSIONS

The ADC was equivalent to placebo in providing temporary relief of URI symptoms in preschool children. However, the ADC did have significantly greater sedative effects than did placebo.

The influence of provider behavior, parental characteristics, and a public policy initiative on the immunization status of children followed by private pediatricians: a study from Pediatric Research in Office Settings

OBJECTIVES

To determine the relative impact of parental characteristics, provider behavior, and the provision of free vaccines through state-sponsored vaccine volume programs (VVPs) on the immunization status of children followed by private pediatricians.

STUDY DESIGN

Retrospective and cross-sectional surveys of immunization data.

SETTING

The offices of 15 private pediatricians, from 11 states, who were members of the Pediatric Research in Office Settings network. Seven of these physicians used vaccines provided through VVPs.

PATIENTS

Children 2 to 3 years old followed by the participating physicians.

METHODS

The immunization status of children was assessed from two separate samples. For sample 1, immunization data were abstracted from the medical records of 60 consecutive eligible children seen in each office. Parents of the selected children indicated the method of payment for immunizations and the education levels of the mothers. Because this cross-sectional survey might have oversampled frequent health care users, a retrospective chart review of up to 75 randomly selected children in each pediatrician's practice was also conducted (sample 2). Additional data were collected from the parents of children in sample 2 by telephone interviews. For both samples, patients were considered to be fully immunized if they had received four diphtheria-tetanus-pertussis/diphtheria-tetanus vaccines, three oral poliovirus/inactivated poliovirus vaccines, and one measles-mumps-rubella vaccine before their second birthdays. Before collecting vaccination data, pediatricians completed a survey detailing their immunization beliefs and practices. Logistic regression was used to identify factors that were independently associated with a child being fully immunized.

RESULTS

For sample 1, 81.7% of the 857 children surveyed were fully immunized. Practitioner-specific immunization rates varied widely, ranging from 51% to 97%. The immunization rate of children who received vaccines provided by VVPs was similar to that of children whose immunizations were not provided by VVPs (81.2% vs 82.2%; odds ratio [OR] for a VVP as a predictor for being fully immunized, 0.94, 95% confidence interval [CI], 0.66 to 1.32). In addition, parents who paid for immunizations out of pocket were as likely to have fully immunized children as those who had little or no out-of-pocket expenditures for vaccines (OR, 1.13; 95% CI, 0.75 to 1.13). In the logistic model, only individual pediatrician and size of the metropolitan area in which the pediatrician's practice was located were significant predictors of a child's immunization status. The results from sample 2 were similar; 82.1% of the 772 surveyed patients were fully immunized. With sample 2, individual pediatrician and age of the child at the time of the survey were the only predictors of immunization status. The OR of a VVP as a predictor of a child being fully immunized was 1.37 (95% CI, 0.65 to 2.90).

CONCLUSIONS

Individual provider behavior may be the most important determinant of the immunization status of children followed by private pediatricians. In our samples, the effect of parental characteristics was limited. State-sponsored VVPs were not associated with higher immunization rates, perhaps because cost of vaccines did not seem to be a significant barrier to immunization in this population.

Predictors of antipsychotic withdrawal or dose reduction in a randomized controlled trial of provider education

OBJECTIVES

To evaluate the effects of an educational program to reduce antipsychotic use in nursing homes that had high use rates post-OBRA-87 and to identify factors that predicted antipsychotic withdrawal or 50% or greater dose reduction.

DESIGN/SETTING

A randomized controlled trial (RCT) of the educational program (nursing home the unit of randomization and analysis) was conducted in 12 Tennessee nursing homes (6 education/6 control). Cohort analysis in baseline antipsychotic users identified factors predicting withdrawal or dose reduction.

SUBJECTS

The RCT analysis included 1152 patients in the homes at baseline and 6 months. The cohort analysis included 133 baseline antipsychotic users in the five education homes able to implement the recommendations of the educational program.

OUTCOME MEASURES

Change in days of antipsychotic use per 100 days of nursing home residence, withdrawal from antipsychotics, reduction in antipsychotic dose by 50% or more.

RESULTS

Following the educational intervention, use of antipsychotics in the six education homes decreased from 25.3 days per 100 at baseline to 19.7 days per 100 by month 6, a 23% reduction relative to control homes (P = .014). In the withdrawal analysis, 44 (33%) of 133 baseline antipsychotic users were withdrawn. Factors at baseline predicting successful withdrawal were low antipsychotic dose, no use of benzodiazepines or antidepressants, and behavioral symptoms score below the median. However, although an additional 22 patients had dose reductions > or = 50%, none of the predictors of withdrawal were associated with dose reductions.

CONCLUSIONS

Focused provider education programs may facilitate antipsychotic reduction above and beyond that attributable to regulatory changes. Patients who are poor candidates for total antipsychotic withdrawal may tolerate substantial dose reductions, which should reduce their risk of adverse antipsychotic effects.

Failure of cannabinoid compounds to stimulate estrogen receptors

delta 9-Tetrahydrocannabinol (THC), the primary active compound in Cannabis sativa (marihuana), and other cannabinoid receptor agonists exert potent effects on luteinizing hormone and prolactin release in animal models and humans. Compounds possessing the tricyclic cannabinoid structure, including delta 9-THC and cannabidiol, have been reported to interact with rodent uterine estrogen receptors in ligand binding assays. The present study tested the hypothesis that cannabinoid compounds produce a direct activation of estrogen receptors. We investigated whether cannabinoid compounds exhibit estrogen-induced mitogenesis in MCF-7 breast cancer cells. Under conditions in which 10 pM estradiol promoted MCF-7 cell proliferation, no response was observed with biologically relevant concentrations (< = 10 microM) of delta 9-THC or its tricyclic analog desacetyllevonantradol. No response was observed with cannabidiol, a bicyclic cannabinoid compound that exhibits no cannabimimetic behavioral effects but has been reported to bind to the estrogen receptor in vitro. delta 9-THC also failed to antagonize the response to estradiol under conditions in which the antiestrogen LY156758 (keoxifene; raloxifene) was effective. The phytoestrogen formononetin behaved as an estrogen at high concentrations, and this response was antagonized by LY156758. We also investigated the ability of cannabinoid compounds to stimulate transcription of an EREtkCAT reporter gene transiently transfected into MCF-7 cells. Neither delta 9-THC, desacetyllevonantradol, nor cannabidiol stimulated transcriptional activity. We conclude that psychoactive or inactive compounds of the cannabinoid structural class fail to behave as agonists in appropriate assays of estrogen receptor responses in vitro.

Expression of amphiregulin in the sheep mammary gland

The reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify, from sheep mammary gland total RNA, a 280 bp sequence of amphiregulin cDNA. Cloned and sequenced, it corresponded to the 78 amino acids of the major secreted form of amphiregulin, showing 81, 70 and 69% identity with human, rat and mouse amphiregulin, respectively. Expression of amphiregulin was detected by RT-PCR in the mammary gland at several developmental stages (fetal, lamb, early and late pregnant and lactating ewes) and in isolated myoepithelial cells. By Western blotting with an antiserum to human amphiregulin, two molecular weight forms, 27 and 51 kDa were detected in sheep mammary gland microsomal preparations, in a mammary gland extract after heparin affinity chromatography and in a medium conditioned by mammary epithelial cells. By immunocytochemistry, amphiregulin was detected in the cytoplasm and nuclei of luminal epithelial cells, myoepithelial cells and in intralobular stroma. An autocrine/paracrine role in sheep mammary growth is indicated.

Estrogen receptors are essential for female sexual receptivity

One of the most important, robust and evolutionarily conserved functions for neural estrogen receptor (ER) is as a mediator of female sexual behavior. Using homozygotic ER knockout (ERKO) mice we tested the hypothesis that ER controls female receptivity. Females with either two normal copies of the ER gene (wild-types), or an insertational disruption (knockouts) of the ER were ovariectomized. Each female was treated with 17 beta-estradiol (EB) alone, and with EB in combination with progesterone, prior to tests for behavioral receptivity. Under both hormonal conditions female ERKO mice did not display sexual receptivity whereas wild-type litter-mates were receptive to males. Male behavior indicated that females of both genotypes were equally attractive. Brain tissues were examined with immunocytochemical methods showed that ERKOs had greatly reduced levels of ER immunoreactivity in hypothalamus. In sum, the data show that ER is required for the display of sexual receptivity, but is not essential for female attractivity.

Sequence database searches via de novo peptide sequencing by tandem mass spectrometry

A method is described for searching protein sequence databases using tandem mass spectra of tryptic peptides. The approach uses a de novo sequencing algorithm to derive a short list of possible sequence candidates which serve as query sequences in a subsequent homology-based database search routine. The sequencing algorithm employs a graph theory approach similar to previously described sequencing programs. In addition, amino acid composition, peptide sequence tags and incomplete or ambiguous Edman sequence data can be used to aid in the sequence determinations. Although sequencing of peptides from tandem mass spectra is possible, one of the frequently encountered difficulties is that several alternative sequences can be deduced from one spectrum. Most of the alternative sequences, however, are sufficiently similar for a homology-based sequence database search to be possible. Unfortunately, the available protein sequence database search algorithms (e.g. Blast or FASTA) require a single unambiguous sequence as input. Here we describe how the publicly available FASTA computer program was modified in order to search protein databases more effectively in spite of the ambiguities intrinsic in de novo peptide sequencing algorithms.

Visual acuity, erythrocyte fatty acid composition, and growth in term infants fed formulas with long chain polyunsaturated fatty acids for one year. Ross Pediatric Lipid Study

The CNS and the retina are enriched in long chain polyunsaturated (LCP) fatty acids, specifically docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (AA, 20:4n-6), which are present in human milk but not in most infant formulas. In the present study of 134 formula-fed and 63 breast-fed infants, we prospectively evaluated whether providing a source of DHA and AA or DHA alone in formula would increase red blood cell (RBC) phospholipid levels of these fatty acids, enhance visual function, or affect growth during the first year. Healthy term infants < 7 d old were randomized to be fed formulas containing linoleic acid (approximately 10% kcal) and alpha-linolenic acid (approximately 1% kcal) plus (1) no added LCP fatty acids (control formula), (2) DHA (0.12 wt% fatty acids) and AA (0.43 wt%) from egg yolk phospholipid (AA + DHA formula), or (3) DHA (0.2 wt%) from fish oil (DHA formula). A breast-fed group was studied concurrently and permitted formula supplementation after 3 mo. Visual acuity was measured using both the acuity card procedure and a visual evoked potential method at 2, 4, 6, 9, and 12 mo. Infants fed the control formula had 10-40% lower RBC levels of DHA and AA than infants in the breast-fed group. Infants fed the AA + DHA formula had levels of both LCP within approximately 10% of the values for infants in the breast-fed group, and infants fed the DHA formula had 25-55% higher DHA levels and 15-40% lower AA levels. There were no differences in growth or in visual function during this 12-mo feeding study.