Tricyclic farnesyl protein transferase inhibitors: crystallographic and calorimetric studies of structure-activity relationships.

Crystallographic and thermodynamic studies of farnesyl protein transferase (FPT) complexed with novel tricyclic inhibitors provide insights into the observed SAR for this unique class of nonpeptidic FPT inhibitors. The crystallographic structures reveal a binding pattern conserved across the mono-, di-, and trihalogen series. In the complexes, the tricycle spans the FPT active site cavity and interacts with both protein atoms and the isoprenoid portion of bound farnesyl diphosphate. An amide carbonyl, common to the tricyclic compounds described here, participates in a water-mediated hydrogen bond to the protein backbone. Ten high-resolution crystal structures of inhibitors complexed with FPT are reported. Included are crystallographic data for FPT complexed with SCH 66336, a compound currently undergoing clinical trials as an anticancer agent (SCH 66336, 4-[2-[4-(3,10-dibromo-8-chloro-6,11-dihydro-5H-benzo[5, 6]cyclohepta[1, 2-b]pyridin-11-yl)-1-piperidinyl]-2-oxoethyl]-1-piperidinecarbo xamide ). Thermodynamic binding parameters show favorable enthalpies of complex formation and small net entropic contributions as observed for 4-[2-[4-(3,10-dibromo-8-chloro-6,11-dihydro-11H-benzo[5, 6]cyclohepta[1, 2-b]pyridin-11-ylidene)-1-piperidinyl]-2-oxoethyl]pyridine N-oxide where DeltaH degrees bind = -12.5 kcal/mol and TDeltaS degrees bind = -1.5 kcal/mol.     

Enterococcal endocarditis: clinical and microbiological features of our series

Of 81 cases of infectious endocarditis seen at our institution from 1988 to 1995, 61 had positive culture (75%) and, of these, 10 (16%) were caused by enterococcal strains (9 by Enterococcus faecalis, 1 by Enterococcus faecium). The 10 cases consisted of 5 native valve endocarditis and 5 late prosthetic valve endocarditis. Median age of patients was 50 years (range 21-58); 6, were males. Diagnostic or surgical procedures on the abdomen, genito-urinary tract, or chest preceded the onset of fever in almost all cases. Nine enterococcal strains showed low-level resistance to aminoglycosides and one was highly resistant. Seven patients were treated with ampicillin and gentamicin and 2 with teicoplanin and gentamicin. The patient, whose infection was caused by an high gentamicin-resistant E. faecalis, was treated with the combination of ciprofloxacin and cotrimoxazole chosen on the basis of the in vitro susceptibility tests. Congestive heart failure occurred in 4 patients and major embolic events in 3. All patients were cured; 4, with medical therapy alone and 6, with antimicrobials associated with surgical substitution of the valve. The data indicate that enterococcal endocarditis, when treated with appropriate antimicrobial regimens, associated with surgical treatment when necessary, has a very low mortality rate. The conventional treatment, -lactams plus gentamicin is usually effective. However, for high-level gentamicin-resistant strains alternative treatments must be selected on the basis of the in vitro susceptibility tests.     

Alkamides from Cissampelos glaberrima

Two alkamides, deca-2E,4E-dienoic acid isobutylamide (1) and octa-2E,4E-dienoic acid isobutylamide (2), were isolated from the roots of Cissampelos glaberrima (Menispermaceae). Their structures were established by spectral and physical methods. Traces of two new alkamides, decen-2-oic acid isobutylamide (3) and decanoic acid isobutylamide (4), were identified by mass spectrometry.     

The epidemiology of endometrial cancer in young women

A case-control study was conducted in Los Angeles County, California, of 127 endometrial cancer cases aged 45 years or less at diagnosis, to investigate the role of fertility, obesity and exogenous oestrogens in the development of the disease in young women. Use of sequential oral contraceptive (SOCs) or oestrogen replacement therapy (ERT) for greater than or equal to 2 years was strongly associated with increased risk of endometrial cancer. After excluding these cases, since the SOC or ERT use was probably the cause of their disease, we were left with 110 case-control pairs for further study. Among these remaining case-control pairs increasing parity was strongly associated with decreased risk (relative risk of 0.12 for women of parity 3 compared to nulliparous women, P less than 0.001). Current weight was associated with increased risk (relative risk of 17.7 for women weighing greater than or equal to 190 lbs compared to women weighing less than 130 lbs, P less than 0.001). Combination oral contraceptive (COC) use was associated with a decreased risk, which decreased with duration of COC use (relative risk of approximately 0.28 at 5 years of use, P less than 0.001), but the estimate of the protective effect was reduced and became statistically non-significant when allowance was made for weight and parity. The protective effect of COC use was only clearly evident in women who had less than 3 live-births and weighed less than 170 lbs. These results provide further support for the "unopposed" oestrogen hypothesis of the aetiology of endometrial cancer.     

Lipid-associated sialic acid levels in human breast cyst fluids

Summary Benign mammary gross cystic disease is the most common breast lesion. Women with apocrine changes of epithelium lining the cysts are at higher risk for developing breast cancer than the normal female population. Sialic acid has drawn considerable interest because of carbohydrate aberrations in malignant cells. The current investigation determined the concentrations of lipid-associated sialic acid (LASA) in 62 breast cyst fluids and sera. Data analyses show a significant increase in the mean values of LASA in metabolically active apocrine cysts when compared to the cysts with Na⁺/K⁺>3 (flattened cysts) (p<0.001). The greater LASA levels in cyst fluids with lower intracystic Na⁺/K⁺ ratios could represent an altered expression of biosynthetic activity of the surrounding apocrine cell surface sialoglycolipid metabolism, providing a possible explanation of why women with apocrine cysts may be at greater cancer risk and being useful in further studies on functional stage changes in the cysts and their relationship to breast cancer.     

Spatial and Temporal Patterns of Neurogenesis in the Chick Retina

Chick embryo retinas were labelled in ovo by single injections of [3H]thymidine at selected times between days 2 and 12 of incubation. Embryos were later removed, at different stages of development, and the retinas processed for autoradiography of either serial sections or dissociated cell preparations. Analysis of unlabelled cells shows that neurogenesis starts, on day 2 of incubation, in a dorsotemporal area of the central retina, close to the posterior pole and to the optic nerve head. A gradient of neurogenesis spreads from this central area to the periphery, where neurogenesis ends, shortly after day 12, when the last few bipolar cells withdraw from the cell cycle. Additional dorsal-to-ventral and temporal-to-nasal gradients can be discerned in our autoradiographs. In all retinal sectors, ganglion cells start first to withdraw from the cell cycle, followed, with substantial overlapping, by amacrine, horizontal, photoreceptor plus Müller, and bipolar neuroblasts. Ganglion cells are also the first to reach the 50% level of unlabelled cells, followed this time by horizontal, photoreceptor, amacrine, Müller and bipolar cells. Finally, 100% levels of unlabelled cell populations are attained simultaneously by ganglion, horizontal and photoreceptor cells, followed by amacrine, then by Müller, and last by bipolar cells. Although all classes of neurons, in varying proportions, are being produced most of the time, our results also demonstrate that, in any given retinal area, the first cells leaving the cycle are determined to become ganglion cells, and the last ones bipolar cells, and not other types.     

Inactivation of adenosine A2A receptors selectively attenuates amphetamine-induced behavioral sensitization.

Repeated treatment with the psychostimulant amphetamine produces behavioral sensitization that may represent the neural adaptations underlying some features of psychosis and addiction in humans. In the present study we investigated the role of adenosine A(2A) receptors in psychostimulant-induced locomotor sensitization using an A(2A) receptor knockout (A(2A) KO) model. Daily treatment with amphetamine for 1 week resulted in an enhanced motor response on day 8 (by two-fold compared to that on day 1), and remained enhanced at day 24 upon rechallenge with amphetamine. By contrast, locomotor sensitization to daily amphetamine did not develop in A(2A) KO mice on day 8 or 24, and this absence was not the result of a nonspecific threshold effect. The absence of behavioral sensitization was selective for amphetamine since daily treatment with the D(1) agonist SKF81297 (2.5 mg/kg) or the D(2) agonist quinpirole (1.0 mg/kg) produced similar behavioral sensitization in both WT and A(2A) KO mice. Furthermore, coinjection of SKF81297 and quinpirole also resulted in indistinguishable locomotor sensitization in A(2A) KO and WT mice, suggesting normal D(1) and D(2) receptor responsiveness. Finally, at the cellular level A(2A) receptor inactivation abolished the increase in striatal dynorphin mRNA induced by repeated amphetamine administration. The selective absence of amphetamine-induced behavioral sensitization in A(2A) KO mice suggests a critical role of the A(2A) receptor in the development of psychostimulant-induced behavioral sensitization, and supports the pharmacological potential of A(2A) adenosinergic agents to modulate adaptive responses to repeated psychostimulant exposure.     

Colorectal cancer screening knowledge, attitudes, and beliefs among veterans: does literacy make a difference?

PURPOSE: To evaluate whether lower literacy is associated with poorer knowledge and more negative attitudes and beliefs toward colorectal cancer screening among veterans without recent colorectal cancer screening. PATIENTS AND METHODS: Three hundred seventy-seven male veterans, age 50 years and older, who had not undergone recent colorectal cancer screening, were surveyed about their knowledge, attitudes, and beliefs regarding colorectal cancer screening. Patients' literacy was assessed with the Rapid Estimate of Adult Literacy in Medicine, an individually administered screening test for reading. RESULTS: Thirty-six percent of the 377 men had an eighth grade literacy level or higher. Men with lower literacy were 3.5 times as likely not to have heard about colorectal cancer (8.8% v 2.5%; P =.006), 1.5 times as likely not to know about screening tests (58.4% v 40.9%; P =.0001), and were more likely to have negative attitudes about fecal occult blood testing (FOBT), but not about flexible sigmoidoscopy. Specifically, men with lower literacy skills were two times as likely to be worried that FOBT was messy (26.7% v 13.3%; P =.008), 1.5 times as likely to feel that FOBT was inconvenient (28.7% v 18%; P =.05), and four times as likely to state they would not use an FOBT kit even if their physician recommended it (17.9% v 4.0%; P =.02). CONCLUSION: Limited literacy may be an overlooked barrier in colorectal cancer screening among veterans.     

Prognostic value of CD40 in adult soft tissue sarcomas.

PURPOSE: The purpose is to evaluate the expression of CD40, a membrane protein predominantly expressed on B cells, dendritic cells, and macrophages, in a series of adult soft tissue sarcomas and to test its possible prognostic value. EXPERIMENTAL DESIGN: CD40 expression was studied by immunohistochemistry. Correlations with other baseline characteristics of patients and tumors were analyzed with chi(2) test. The prognostic value was studied with univariable and multivariable analysis adjusted by age, sex, tumor size, grade, location, and distant metastases. RESULTS: Eighty-two patients, between January 1994 and May 2001, were analyzed. Membrane or cytoplasmic staining for CD40 protein was absent in 30% of the tumors but present in <10% of cells in 22 (27%), in 10% to 50% in 23 (28%), and in >50% of cells in 12 (15%) tumors. There was no correlation between CD40 expression and age, sex, size, grade, and location of the primary tumor and distant metastases. With 61 patients (74.4%) progressed and 31 (37.8%) dead, CD40 expression was a significant prognostic factor for disease-free and overall survival at univariable and multivariable analysis. Patients with tumors expressing CD40 in >50% of cells had a dramatically unfavorable prognosis with median disease-free and overall survival of 7 and 17 months, respectively, and hazard ratios of relapse and death as compared with patients with CD40-negative tumors of 2.89 (95% confidence interval: 1.26-6.60) and 6.92 (95% confidence interval: 2.18-22.0), respectively. CONCLUSIONS: These data suggest that expression of CD40 protein in >50% of cells might indicate an unfavorable prognosis in adult soft tissue sarcomas.