Farnesyl transferase inhibitors block the farnesylation of CENP-E and CENP-F and alter the association of CENP-E with the microtubules

Human tumor cell lines that are sensitive to the effects of farnesyl transferase inhibitors accumulate in G(2) --> M (except for cells with an activated Ha-ras that accumulate in G(1)). A search for CAAX box proteins from Swiss-Prot revealed more than 300 peptides. Of these, the centromeric proteins CENP-E and CENP-F are preferentially expressed during mitosis and are implicated as mediators of the G(2) --> M checkpoint. Experiments performed here show that peptides from the COOH-terminal CAAX box of CENP-E and CENP-F are substrates for farnesyl transferase but not geranylgeranyl transferase-I. Although both proteins are prenylated in the human tumor cell line DLD-1, their prenylation is completely inhibited by the farnesyl transferase inhibitor, SCH 66336. Immunohistochemical data with the lung carcinoma cell line, A549, showed that preventing the farnesylation of CENP-E and CENP-F by treatment with the farnesyl transferase inhibitor SCH 66336 does not affect their localization to the kinetochores. However, the presence of farnesyl transferase inhibitors alters the association between CENP-E and the microtubules. Our results imply that the inhibition of CENP-E farnesylation results in the alteration of the microtubule-centromere interaction during mitosis and results in the accumulation of cells prior to metaphase.

Efficacy of potential chemopreventive agents on rat colon aberrant crypt formation and progression

We assessed the effects of 78 potential chemopreventive agents in the F344 rat using two assays in which the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon was the measure of efficacy. In both assays ACF were induced by the carcinogen azoxymethane (AOM) in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last AOM injection, animals were evaluated for the number of aberrant crypts detected in methylene blue stained whole mounts of rat colon. In the initiation phase protocol agents were given during the period of AOM administration, whereas in the post-initiation assay the chemopreventive agent was introduced during the last 4 weeks of an 8 week assay, a time when ACF had progressed to multiple crypt clusters. The agents were derived from a priority listing based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. During the initiation phase carboxyl amidoimidazole, p-chlorphenylacetate, chlorpheniramine maleate, D609, diclofenac, etoperidone, eicosatetraynoic acid, farnesol, ferulic acid, lycopene, meclizine, methionine, phenylhexylisothiocyanate, phenylbutyrate, piroxicam, 9-cis-retinoic acid, S-allylcysteine, taurine, tetracycline and verapamil were strong inhibitors of ACF. During the post-initiation phase aspirin, calcium glucarate, ketoprofen, piroxicam, 9-cis-retinoic acid, retinol and rutin inhibited the outgrowth of ACF into multiple crypt clusters. Based on these data, certain phytochemicals, antihistamines, non-steroidal anti-inflammatory drugs and retinoids show unique preclinical promise for chemoprevention of colon cancer, with the latter two drug classes particularly effective in the post-initiation phase of carcinogenesis.

Endocervical cancer is associated with an increase in the ligands and receptors for transforming growth factor-beta and a contrasting decrease in p27(Kip1)

OBJECTIVE

The aim of this study was to investigate the relationship between the expression of the TGF-beta ligands and TGF-beta receptors to the expression of p27(Kip1), a TGF-beta-regulated gene, in endocervical cancer.

METHODS

To examine the expression of TGF-beta and p27(Kip1) in malignant transformation of the uterine endocervix, a panel of 23 formalin-fixed and paraffin-embedded human cervical specimens, including 8 with benign endocervical glands, 8 with cervical adenocarcinoma in situ, and 7 with cervical adenocarcinomas, was used. Tissues were immunostained with polyclonal antibodies that react specifically with TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-beta RI, TGF-beta RII, and p27(Kip1).

RESULTS

Immunostaining for TGF-beta 1, TGF-beta 2, TGF-beta 3, TGF-beta RI, TGF-beta RII, and p27(Kip1) was detected in normal endocervix, with the TGF-betas showing weak cytoplasmic staining, while p27(Kip1) showed strong nuclear staining. Expression of TGF-beta increased significantly upon neoplastic transformation with the TGF-beta ligands and receptors showing strong cytoplasmic staining in adenocarcinoma in situ compared to normal endocervix. Interestingly, expression of TGF-beta was lower in adenocarcinoma than in adenocarcinoma in situ, but still significantly higher than in normal endocervix. TGF-beta 2 and TGF-beta 3 showed higher levels of immunostaining than TGF-beta 1 in adenocarcinomas. In contrast, p27(Kip1) protein expression decreased with progressive malignancy, with lower p27(Kip1) protein levels detected in adenocarcinoma than in adenocarcinoma in situ, while normal endocervix showed the highest level of p27(Kip1) protein expression.

CONCLUSION

Elevated expression of the TGF-beta ligands and receptors is found in both cervical adenocarcinoma in situ and adenocarcinoma compared to normal endocervix. In contrast, a progressive decrease in p27(Kip1) occurs upon neoplastic transformation of the normal endocervix to cervical adenocarcinoma. These results suggest that neoplastic transformation of the endocervix may be related to dysregulation of TGF-beta and p27(Kip1) seen as an elevation of TGF-beta and a reduction of p27(Kip1) expression that may lead to loss of cell cycle control.

Effects of forearm bier block with bretylium on the hemodynamic and metabolic responses to handgrip

We tested the hypothesis that a reduction in sympathetic tone to exercising forearm muscle would increase blood flow, reduce muscle acidosis, and attenuate reflex responses. Subjects performed a progressive, four-stage rhythmic handgrip protocol before and after forearm bier block with bretylium as forearm blood flow (Doppler) and metabolic (venous effluent metabolite concentration and (31)P-NMR indexes) and autonomic reflex responses (heart rate, blood pressure, and sympathetic nerve traffic) were measured. Bretylium inhibits the release of norepinephrine at the neurovascular junction. Bier block increased blood flow as well as oxygen consumption in the exercising forearm (P < 0.03 and P < 0.02, respectively). However, despite this increase in flow, venous K(+) release and H(+) release were both increased during exercise (P < 0.002 for both indexes). Additionally, minimal muscle pH measured during the first minute of recovery with NMR was lower after bier block (6.41 +/- 0.08 vs. 6.20 +/- 0.06; P < 0.036, simple effects). Meanwhile, reflex effects were unaffected by the bretylium bier block. The results support the conclusion that sympathetic stimulation to muscle during exercise not only limits muscle blood flow but also appears to limit anaerobiosis and H(+) release, presumably through a preferential recruitment of oxidative fibers.

Modulation of endometrial steroid receptors and growth regulatory genes by tamoxifen

OBJECTIVE

We investigated tamoxifen's effects on the expression of growth regulatory genes in the endometrium to identify the mechanism by which tamoxifen induces proliferation.

METHODS

Using immunohistochemical techniques, we analyzed 39 endometrial specimens for expression of Ki-67, lactoferrin, transforming growth factor-alpha, tumor necrosis factor receptor-II, adrenomedullin, estrogen receptors, and progesterone receptors. Twenty specimens were obtained from postmenopausal breast cancer patients treated with tamoxifen (20 mg/day) for at least 6 months to include two endometrial adenocarcinoma specimens. Five secretory phase, three proliferative phase, and seven atrophic endometrial specimens were used as controls. In addition, four endometrial adenocarcinoma specimens were reviewed from patients not treated with tamoxifen. Intensity of immunostaining was quantified using digitized imaging techniques.

RESULTS

Overexpression of both estrogen receptors and progesterone receptors, and an elevated proliferative index were the most consistent effects observed in benign endometrial specimens from tamoxifen-treated patients compared with atrophic controls (P <. 003). This staining pattern was also evident in adenocarcinomas from patients who received tamoxifen. Benign endometrium from tamoxifen-treated patients also expressed transforming growth factor-alpha, tumor necrosis factor receptor-II, lactoferrin, and adrenomedullin at levels comparable with those found in proliferative endometrial specimens.

CONCLUSION

These data provide further documentation that the uterotropic effects of tamoxifen may be due, at least in part, to the induction of estrogen receptors and progesterone receptors, as well as other genes associated with the proliferative phase. Furthermore, analysis of estrogen receptors, progesterone receptors, and Ki-67 may be useful in identifying postmenopausal individuals on tamoxifen, who are at increased risk for developing endometrial cancer.

Expression of brx proto-oncogene in normal ovary and in epithelial ovarian neoplasms

OBJECTIVE

We previously identified a protein, Brx, that interacted with estrogen receptor alpha. Sequence analysis determined that Brx is a novel member of the Dbl family of oncoproteins involved in signaling pathways that regulate cell growth. Because the Brx protein was found to be highly expressed in hormoneresponsive breast epithelium, the objective of this study was to determine whether Brx was expressed in both normal and neoplastic ovarian tissues.

STUDY DESIGN

A polyclonal antiserum directed against the Brx protein was used to perform immunolocalization on sections from 5 normal ovaries and 20 ovarian neoplasms. Chromosomal localization of the brx gene was accomplished by means of fluorescence in situ hybridization. Northern and Western blot analyses were performed on extracts prepared from human ovaries.

RESULTS

Brx protein was localized to the cytoplasm of granulosa cells from mature graafian follicles, the corpus luteum, and islands of hilar cells in normal ovaries. In tumors with low malignant potential and ovarian carcinomas the neoplastic epithelium stained strongly for Brx protein. Northern and Western blot analyses, respectively, confirmed expression of Brx messenger ribonucleic acid and protein in normal ovary. Finally, the brx gene was localized to 15q25.

CONCLUSION

The proto-oncogene brx is expressed in specific normal human ovarian tissues and is also present in ovarian epithelial neoplasms.

Adenosine contributes to hypoxia-induced forearm vasodilation in humans

In humans, hypoxia leads to increased sympathetic neural outflow to skeletal muscle. However, blood flow increases in the forearm. The mechanism of hypoxia-induced vasodilation is unknown. To test whether hypoxia-induced vasodilation is cholinergically mediated or is due to local release of adenosine, normal subjects were studied before and during acute hypoxia (inspired O(2) 10.5%; approximately 20 min). In experiment I, aminophylline (50-200 microg. min(-1). 100 ml forearm tissue(-1)) was infused into the brachial artery to block adenosine receptors (n = 9). In experiment II, cholinergic vasodilation was blocked by atropine (0.4 mg over 4 min) infused into the brachial artery (n = 8). The responses of forearm blood flow (plethysmography) and forearm vascular resistance to hypoxia in the infused and opposite (control) forearms were compared. During hypoxia (arterial O(2) saturation 77 +/- 2%), minute ventilation and heart rate increased while arterial pressure remained unchanged; forearm blood flow rose by 35 +/- 6% in the control forearm but only by 5 +/- 8% in the aminophylline-treated forearm (P < 0.02). Accordingly, forearm vascular resistance decreased by 29 +/- 5% in the control forearm but only by 9 +/- 6% in the aminophylline-treated forearm (P < 0.02). Atropine did not attenuate forearm vasodilation during hypoxia. These data suggest that adenosine contributes to hypoxia-induced vasodilation, whereas cholinergic vasodilation does not play a role.

Out-patient and home-parenteral antibiotic therapy (OHPAT): evaluation of the impact of one year's experience in Tayside

OBJECTIVE

An out-patient and home parenteral antibiotic therapy programme for the treatment of suitable infections was developed over a four year period. This paper describes the impact of one year's experience of its implementation on various measures of outcome.

DESIGN

Each patient treatment has a full integrated care pathway (ICP) and patient satisfaction questionnaire completed. The ICP documents the clinical progress of the patient and incorporates various measures of quality of care on the 101 number of patients treated from April 1998 to March 1999 are presented here.

SETTING

Dundee Teaching Hospitals NHS Trust (now Tayside University Hospitals NHS Trust).

SUBJECTS

Patients with a range of infections requiring intravenous antibiotics.

MAIN MEASURES

Number of patients treated with various infections, clinical and microbiological outcome, drug and vascular access complication rates, impact on drug costs and in-patient bed days, and measurement of patient satisfaction/quality of life.

RESULTS

Patients were treated over a 12 month period. 51.5 per cent had skin & soft tissue infections and 22.8 per cent bone & joint sepsis. 57 per cent of patients received out-patient and 34 per cent self or carer administered home therapy. Ninety-four per cent of patients were cured or improved following treatment. Only 7.5 per cent of patients required an unscheduled admission to hospital. Twelve per cent of patients had some type of vascular device related adverse event (partly due to a faulty batch of lines) and six per cent of patients had a drug related reaction. The additional daily cost of drugs was minimal (< 12 Pounds/day) and more than 1,461 bed days have been saved across the Directorates. The patient satisfaction level was high.

Accuracy of dose calculation methods for retraced tissue compensators

Uncertainties arise in dose calculations involving retracted tissue compensators due to the effects of the compensator upon the scatter component of the dose. Many commercial treatment-planning systems cannot allow directly for the presence of a compensator in isodose calculation or else use simple 2D methods. We present data to test calculation accuracy for a wax compensation system by comparing retraction factors measured along central-axis and off-axis raylines for a variety of compensator shapes, with those derived using effective attenuation coefficient and 3D analytical calculations. The accuracy of using measured uniform-thickness retraction factors for non-uniform shapes and the dose uniformity achievable using a simple compensation system are also discussed. We conclude that the accuracy of simple calculation methods is shape dependent and that calculation errors and dose variations can exceed +/-5% where missing-tissue thickness variations are large. The analytical method is shown to give good agreement with experiment and indicates that it should be possible to adapt algorithms that calculate scatter from the patient for use with compensators.

Induction of epithelial neoplasms in the ovaries of guinea pigs by estrogenic stimulation

OBJECTIVE

We have been searching for an animal model for ovarian epithelial neoplasms. Our previous study suggested that by giving intermediate doses of testosterone to guinea pigs it is possible to induce cystadenomas in the ovaries in 6 to 10 months.

METHODS

In this study we investigated the effect of different estrogens including estradiol, diethylstilbestrol (DES), estrone, dienestrol, and hexestrol in 24 guinea pigs. Five guinea pigs received sterile water and were used as controls.

RESULTS

Bilateral serous cysts were seen in the ovaries of five guinea pigs that received low (0.25 and 0.35 mg) and intermediate (0.5 and 0.7 mg) doses of estradiol for 2 to 9 months. Surface papillary neoplasms were seen in the ovaries of four guinea pigs that received DES at an intermediate dose (6 mg) and high doses (10 and 12 mg) for 3 to 12 months. The ovaries of the other guinea pigs were unremarkable. Estradiol was measured by radioimmunoassay in three guinea pigs. In the serum it ranged from 450 to 580 pg/ml, and in the ovarian cystadenomas it ranged from 1020 to 6575 pg/ml.

CONCLUSIONS

(1) It is possible to induce ovarian neoplasms using estrogenic hormones. (2) The best results are obtained with intermediate doses of estradiol and DES. (3) These two hormones induce different lesions: estradiol is associated with cystic lesions and DES with surface papillary tumors. These observations, together with our previous finding that testosterone induces neoplasms with a predominantly glandular pattern, establish the guinea pig as an excellent animal to study ovarian neoplasms, confirm the significance of hormones in the development of ovarian epithelial tumors, and suggest that the different histologic appearance of ovarian epithelial neoplasms might be related to different hormonal effects.

Transferrin in normal and neoplastic endocervical tissues: distribution and receptor expression

OBJECTIVE

Our recent studies showed that lactoferrin seems to be down-regulated in endocervical adenocarcinomas. We extended those studies to examine the expression of transferrin (Tf) and its receptor (TfR) in endocervical carcinogenesis and any relationship to the expression of lactoferrin, steroid receptors and the proliferative index.

STUDY DESIGN

A retrospective study was performed using sections prepared from paraffin-embedded, formalin-fixed surgical specimens of normal endocervix, endocervical adenocarcinoma and cervical adenocarcinoma in situ. Standard immunohistochemical techniques were used to localize Tf and its receptor in the normal and malignant endocervix. In situ detection of mRNA for Tf and the TfR was also performed. The relative intensity of the immunoreaction was estimated using digital computer image analysis. Statistical significance was tested by Student's t test.

RESULTS

No differences in the relative staining intensity for Tf and TfR proteins were noted between normal and neoplastic glands. However, quantitation revealed that a greater number of malignant glands stained positive for TfR than observed in the normal endocervix. Expression of Tf and TfR did not correlate with the expression of steroid receptors and lactoferrin or with the rate of proliferation.

CONCLUSION

We have demonstrated the expression of Tf and its receptor by both normal and malignant endocervical glands. The increased number of malignant endocervical glands expressing TfR may indicate a special requirement for Tf and the iron that it carries. Our data provide evidence for the existence of a Tf, TfR autocrine or paracrine circuit involved in the regulation of normal and abnormal endocervical physiology.

Characterization of Brx, a novel Dbl family member that modulates estrogen receptor action

Regulation of gene activation by the estrogen receptor (ER) is complex and involves co-regulatory proteins, oncoproteins (such as Fos and Jun), and phosphorylation signaling pathways. Here we report the cloning and initial characterization of a novel protein, Brx, that contains a region of identity to the oncogenic Rho-guanine nucleotide exchange (Rho-GEF) protein Lbc, and a unique region capable of binding to nuclear hormone receptors, including the ER. Western and immunohistochemistry studies showed Brx to be expressed in estrogen-responsive reproductive tissues, including breast ductal epithelium. Brx bound specifically to the ER via an interaction that required distinct regions of ER and Brx. Furthermore, overexpression of Brx in transfection experiments using an estrogen-responsive reporter revealed that Brx augmented gene activation by the ER in an element-specific and ligand-dependent manner. Moreover, activation of ER by Brx could be specifically inhibited by a dominant-negative mutant of Cdc42Hs, but not by dominant negative mutants of RhoA or Rac1. Taken together, these data suggest that Brx represents a novel modular protein that may integrate cytoplasmic signaling pathways involving Rho family GTPases and nuclear hormone receptors.

Head-down-tilt bed rest alters forearm vasodilator and vasoconstrictor responses

To test the hypothesis that head-down-tilt bed rest (HDBR) for 14 days alters vascular reactivity to vasodilatory and vasoconstrictor stimuli, the reactive hyperemic forearm blood flow (RHBF, measured by venous occlusion plethysmography) and mean arterial pressure (MAP, measured by Finapres) responses after 10 min of circulatory arrest were measured in a control trial (n = 20) and when sympathetic discharge was increased by a cold pressor test (RHBF + cold pressor test; n = 10). Vascular conductance (VC) was calculated (VC = RHBF/MAP). In the control trial, peak RHBF at 5 s after circulatory arrest (34.1 +/- 2.5 vs. 48.9 +/- 4.3 ml . 100 ml-1 . min-1) and VC (0.34 +/- 0.02 vs. 0.53 +/- 0.05 ml . 100 ml-1 . min-1 . mmHg-1) were reduced in the post- compared with the pre-HDBR tests (P < 0. 05). Total excess RHBF over 3 min was diminished in the post- compared with the pre-HDBR trial (84.8 vs. 117 ml/100 ml, P < 0.002). The ability of the cold pressor test to lower forearm blood flow was less in the post- than in the pre-HDBR test (P < 0.05), despite similar increases in MAP. These data suggest that regulation of vascular dilation and the interaction between dilatory and constrictor influences were altered with bed rest.

Developmentally supportive care in a neonatal intensive care unit: a research utilization project

PURPOSE

To implement three aspects of developmental care: lower noise levels, decreased light levels, and flexed, midline positioning.

DESIGN

Research utilization project. The developmental care interventions were implemented on a daily basis for two hours of "quiet time" during each eight-hour shift.

SAMPLE

49 infants with mean gestational ages of 35.1 +/- 3.2 weeks and mean weights of 2,107 +/- 464 gm.

MAIN OUTCOME VARIABLE

Noise levels, light levels, and flexed midline positioning.

RESULTS

Mean light levels and mean noise levels decreased during "quiet time" on all three shifts during the project. Optimal positioning was achieved 78 percent of the time during the project period observations.

Sympathetic discharge and vascular resistance after bed rest

The effect of -6 degrees head-down-tilt bed rest (HDBR) for 14 days on supine sympathetic discharge and cardiovascular hemodynamics at rest was assessed. Mean arterial pressure, heart rate (n = 25), muscle sympathetic nerve activity (MSNA; n = 16) burst frequency, and forearm blood flow (n = 14) were measured, and forearm vascular resistance (FVR) was calculated. Stroke distance, our index of stroke volume, was derived from measurements of aortic mean blood velocity (Doppler) and R-R interval (n = 7). With these data, an index of total peripheral resistance was determined. Heart rate at rest was greater in the post (71 +/- 2 beats/min)- compared with the pre-HDBR test (66 +/- 2 beats/min; P < 0.003), but mean arterial pressure was unchanged. Aortic stroke distance during post-HDBR (15.5 +/- 1.1 cm/beat) was reduced from pre-HDBR levels (20.0 +/- 1.5 cm/beat) (P < 0.03). Also, MSNA burst frequency was reduced in the post (16.7 +/- 2.8 beats/min)- compared with the pre (25.2 +/- 2.6 beats/min)-HDBR condition (P < 0.01). Bed rest did not alter forearm blood flow, FVR, or total peripheral resistance. Thus reductions in MSNA with HDBR were not associated with a decrease in FVR.

Effect of sucrose acetate isobutyrate (SAIB) ingestion on the hepatobiliary function of normal human male and female volunteers

A study of the effects of sucrose acetate isobutyrate (SAIB) ingestion was conducted in 13 male and 14 female healthy human volunteers. SAIB, in a gum arabic/water emulsion diluted with orange juice, was ingested once daily, at a dose of 20 mg SAIB/kg body weight in a total volume of 1.16 ml/kg body weight, for a period of 2 wk following a 1-week control period. During the control period, the subjects consumed the same preparation without SAIB. The study was performed in a single-blind manner, each subject serving as his or her own control. Haematology and clinical chemistry tests were conducted on blood samples taken on day -6 and day 0 of the control period and at 7 and 15 days during the SAIB dosing period. In addition to routine haematology and clinical chemistry, specific tests of hepatobiliary function included serum alkaline phosphatase, aspartate and alanine aminotransferases, lactic dehydrogenase, gamma-glutamyltransferase, total and direct bilirubin, bile acids and proteins. None of these parameters were affected by ingestion of SAIB. It was concluded that ingestion of 20 mg SAIB/kg body weight daily for 14 days does not affect the hepatobiliary function of human volunteers.

Forearm training reduces the exercise pressor reflex during ischemic rhythmic handgrip

We examined the effects of unilateral, nondominant forearm training (4 wk) on blood pressure and forearm metabolites during ischemic and nonischemic rhythmic handgrip (30 1-s contractions/min at 25% maximal voluntary contraction). Contractions were performed by 10 subjects with the forearm enclosed in a pressurized Plexiglas tank to induce ischemic conditions. Training increased the endurance time in the nondominant arm by 102% (protocol 1). In protocol 2, tank pressure was increased in increments of 10 mmHg/min to +50 mmHg. Training raised the positive-pressure threshold necessary to engage the pressor response. In protocol 3, handgrip was performed at +50 mmHg and venous blood samples were analyzed. Training attenuated mean arterial pressure (109 +/- 5 and 98 +/- 4 mmHg pre- and posttraining, respectively, P < 0.01), venous lactate (2.9 +/- 0.4 and 1.8 +/- 0.3 mmol/l pre- and posttraining, respectively, P < 0.01), and the pH response (7.21 +/- 0.02 and 7.25 +/- 0.01, pre- and posttraining, respectively, P < 0.01). However, deep venous O2 saturation was unchanged. Training increased the positive-pressure threshold for metaboreceptor engagement, reduced metabolite concentrations, and reduced mean arterial pressure during ischemic exercise.

The effects of tamoxifen on endometrial insulin-like growth factor-1 expression

OBJECTIVE

To determine whether modulation of insulin-like growth factor-1 and insulin-like growth factor-binding protein-1 expression underlies the uterotropic effects associated with tamoxifen therapy in postmenopausal breast cancer patients.

METHODS

Using immunohistochemical techniques, we analyzed 37 endometrial specimens from biopsies (n = 18) or hysterectomies (n = 19) for Ki-67, insulin-like growth factor-1, and insulin-like growth factor-binding protein-1 expression. Specifically, five secretory- and three proliferative-phase endometrial specimens were used as controls; 20 specimens (including two endometrial adenocarcinomas) were analyzed from postmenopausal breast cancer patients treated with tamoxifen (20 mg/day) for at least 6 months; and nine endometrial adenocarcinoma specimens from patients not treated with tamoxifen were studied. Intensity of immunostaining was quantified using digitized imaging techniques.

RESULTS

Insulin-like growth factor-1 and insulin-like growth factor-1-binding protein-1 were found to be expressed in normal and neoplastic endometrium of all patients, regardless of tamoxifen treatment. However, insulin-like growth factor-1 expression varied cyclically in histologically normal endometrium, was reduced in undifferentiated endometrial tumors, and was upregulated in tamoxifen-treated specimens. Insulin-like growth factor-binding protein-1 immunostaining did not vary during the menstrual cycle, but it was reduced significantly in benign tamoxifen-exposed tissue and endometrial adenocarcinomas, regardless of degree of differentiation or tamoxifen exposure. No correlation was found between the expression of insulin-like growth factor-1 and insulin-like growth factor-binding protein-1 and the proliferative indices of the tissues examined.

CONCLUSION

The expression of insulin-like growth factor-1 and insulin-like growth factor-binding protein-1 in the uterus supports an autocrine and/or paracrine role for these proteins in endometrial physiology. Although further studies are needed, our investigation suggests that altered expression of insulin-like growth factor-1 and insulin-like growth factor-binding protein-1 may contribute to the uterotropic effects of tamoxifen.

Neoplastic transformation of the endocervix associated with downregulation of lactoferrin expression

The incidence of cervical adenocarcinomas in young women over the last two decades has increased. Even with increasing knowledge of the role of human papillomavirus in the etiology of adenocarcinoma of the cervix, there is a paucity of data concerning the genetic and epigenetic factors that contribute to the histologic features and biologic behaviors of these tumors. Lactoferrin is a basic glycoprotein found in human milk, secondary granules of neutrophils, and many body secretions, and it has been associated with carcinogenesis of the endometrium, breast, and lymphoid systems. In this study, we examined the expression of lactoferrin in normal human endocervical epithelium and in cervical adenocarcinomas in relation to proliferative index, steroid receptor status, p53 protein expression, and apoptosis. Immunohistochemical and in situ studies demonstrated that lactoferrin protein and mRNA were strikingly downregulated upon neoplastic transformation of the endocervix as early as in adenocarcinoma in situ when compared with the prominent expression exhibited by the normal cervical epithelium. Furthermore, neoplastic transformation of endocervical epithelial cells was accompanied by a pronounced stimulation of proliferation and a substantial reduction in the expression of the estrogen and progesterone receptors and p53 but little or no change in the number of apoptotic cells. In conclusion, we identified lactoferrin as a novel cancer-specific marker of endocervical adenocarcinomas that may be useful in the early detection of the disease, prediction of prognosis, and the development of new therapeutic modalities.

The induction of benign epithelial neoplasms of the ovaries of guinea pigs by testosterone stimulation: a potential animal model

We studied the effects of different hormones on the epithelial cells of the ovaries of 11 guinea pigs. Three received testosterone, two received estrone, three megestrol, and three chorionic gonadotropin. Three control guinea pigs received sterile water. Benign epithelial cysts larger than 1.5 mm were found in six guinea pigs, three who received testosterone, one who received megestrol, and two who received chorionic gonadotropin. In one of the three guinea pigs who received testosterone, 2.5-cm bilateral cysts were grossly identified. Papillary excrescences were found on the ovarian surface in four guinea pigs, three who received testosterone and one who received megestrol. The proliferating epithelial cells also formed benign glands in the ovarian stroma in two guinea pigs who received testosterone, the most exuberant epithelial proliferations, including large bilateral cystadenomas, papillary excrescence that formed a small papillary neoplasm, and glands in the ovarian stroma that formed adenomatous areas, were seen in the guinea pig who received an intermediate dose of testosterone for the longest time. By radioimmunoassay, the serum level of testosterone was 22 ng/dL in one of the controls and 10,000, 12,000, and 15,000 ng/dL in the three guinea pigs who received testosterone. In the guinea pig with the most exuberant epithelial proliferation, the level of testosterone in the uterus was similar to that in the serum (13,860 ng/mg), but in the wall of the ovarian epithelial cyst, it was three times higher than it was in the serum (44,000 ng/mg). Our study shows that testosterone stimulates the growth of epithelial cells in the ovaries of guinea pigs, resulting in benign cysts, small adenomas in the ovarian parenchyma, and papillomas on the ovarian surface. The study also shows that guinea pigs can be used as an animal model for epithelial tumors of the human ovary.

Augmented sympathetic tone alters muscle metabolism with exercise: lack of evidence for functional sympatholysis

It is unclear whether sympathetic tone opposes dilator influences in exercising skeletal muscle. We examined high levels of sympathetic tone, evoked by lower body negative pressure (LBNP, -60 mmHg) on intramuscular pH and phosphocreatine (PCr) levels (31P-nuclear magnetic resonance spectroscopy) during graded rhythmic handgrip (30 contractions/min; approximately 17, 34, 52 and 69% maximal voluntary contraction). Exercise was performed with LBNP and without LBNP (Control). At the end of exercise, LBNP caused lower levels of muscle pH (6.59 +/- 0.09) compared with Control (6.78 +/- 0.05; P < 0.05). PCr recovery, an index of mitochondrial respiration, was less during the recovery phase of the LBNP trial. Exercise mean arterial pressure was not altered by LBNP. The protocols were repeated with measurements of forearm blood flow velocity and deep venous samples (active forearm) of hemoglobin (Hb) saturation, pH, and lactate. With LBNP, mean blood velocity was reduced at rest, during exercise, and during recovery compared with Control (P < 0.05). Also, venous Hb saturation and pH levels during exercise and recovery were lower with LBNP and lactate was higher compared with Control (P < 0.05). We conclude that LBNP enhanced sympathetic tone and reduced oxygen transport. At high workloads, there was a greater reliance on nonoxidative metabolism. In other words, sympatholysis did not occur.

Rodent models of the human acetylation polymorphism: comparisons of recombinant acetyltransferases

The acetylation polymorphism is associated with differential susceptibility to drug toxicity and cancers related to aromatic and heterocyclic amine exposures. N-Acetylation is catalyzed by two cytosolic N-acetyltransferases (NAT1 and NAT2) which detoxify many carcinogenic aromatic amines. NAT1 and NAT2 also activate (via O-acetylation) the N-hydroxy metabolites of aromatic and heterocyclic amine carcinogens to electrophilic intermediates which form DNA adducts and initiate cancer. The classical N-acetylation polymorphism is regulated at the NAT2 locus, which segregates individuals into rapid, intermediate, and slow acetylator phenotypes. Some human epidemiological studies associate slow acetylator and rapid acetylator phenotypes with increased susceptibility to urinary bladder and colorectal cancers, respectively. The acetylation polymorphism has been characterized in three rodent species (mouse, Syrian hamster, and rat) to test associations between NAT2 acetylator phenotype and susceptibility to aromatic and heterocyclic amine-induced cancers in various tumor target organs. NAT1 and NAT2 from rapid and slow acetylator mouse, Syrian hamster, and rat each have been cloned and sequenced. Recombinant NAT1 and NAT2 enzymes enzymes encoded by these genes have been characterized with respect to their catalytic activities for both activation (O-acetylation) and deactivation (N-acetylation) of aromatic and heterocyclic amine carcinogens. The acetylation polymorphisms in mouse, Syrian hamster, and rat are herein reviewed and compared as models of the human acetylation polymorphism.

Cloning, sequencing, and recombinant expression of NAT1, NAT2, and NAT3 derived from the C3H/HeJ (rapid) and A/HeJ (slow) acetylator inbred mouse: functional characterization of the activation and deactivation of aromatic amine carcinogens

An acetylator polymorphism has been described in the mouse and the inbred strains C3H/HeJ and A/HeJ constitute rapid and slow acetylators, respectively. The NAT1, NAT2, and NAT3 genes from C3H/HeJ and A/HeJ acetylator inbred mouse strains were amplified using the polymerase chain reaction, cloned into the plasmid vector pUC19, and sequenced. They were then subcloned into the prokaryotic expression vector pKK223-3 and expressed in Escherichia coli strain JM105. The 870-bp nucleotide coding region of NAT1 and NAT3 did not differ between the rapid and slow acetylator mouse strains, or from that of previously published mouse NAT1 and NAT3 sequences. However, NAT2 did differ between the rapid and slow acetylator strains with an A296 T transition which causes a (Asn99-->Ile) substitution in the deduced amino acid sequence. Recombinant NAT1, NAT2, and NAT3 proteins catalyzed N-, O-, and N,O-acetyltransferase activities. NAT3 catalyzed aromatic amine N-acetyltransferase activities at very low rates, which confirms a previous study. Apparent K(m) and Vmax kinetic constants for N-acetylation were 5- to 10-fold lower for recombinant mouse NAT1 than NAT2. Intrinsic clearances for recombinant mouse NAT1- and NAT2-catalyzed N-acetylation of aromatic amine carcinogens were comparable. Both recombinant mouse NAT1 and NAT2 catalyzed the metabolic activation of N-hydroxyarylamine (O-acetylation) and N-hydroxyarylamide (N,O-acetylation) carcinogens. Recombinant mouse NAT3 catalyzed N,O-acetylation at very low rates, while O-acetylation was undetectable. No difference was observed between rapid and slow acetylator recombinant NAT2 proteins to activate aromatic amines by O- or N,O-acetylation, in substrate specificity, expression of immunoreactive protein, electrophoretic mobility, or N-acetyltransferase Michaelis-Menten kinetic constants. However, the slow acetylator recombinant NAT2 protein was over 10-fold less stable than rapid acetylator recombinant NAT2. These studies demonstrate metabolic activation and deactivation by recombinant mouse NAT1, NAT2, and NAT3 proteins and confirm and extend previous studies on the molecular basis for the acetylation polymorphism in the mouse.