Autoregulation of nitric oxide-soluble guanylate cyclase-cyclic GMP signalling in mouse thoracic aorta

1. The sensitivity of the soluble guanylate cyclase (sGC)-cyclic guanosine-3',5'-monophosphate (cyclic GMP) system to nitric oxide (NO) was investigated in mouse aorta from wild type (WT) and NO synthase (NOS) knockout (KO) animals. 2. The NO donor, spermine-NONOate (SPER-NO) was more potent in aortas from eNOS KO mice compared to WT (pEC50 7.30+/-0.06 and 6.56+/-0.04, respectively; n=6; P<0.05). In contrast, the non-NO based sGC activator, YC-1 was equipotent in vessels from eNOS WT and KO mice. The sensitivity of aortas from nNOS and iNOS KO animals to SPER-NO was unchanged. Forskolin (an adenylate cyclase activator), was equipotent in vessels from eNOS WT and KO animals. 3. The cyclic GMP analogue, 8-Br-cGMP was equipotent in eNOS WT and KO mice (pEC50 4. 38+/-0.04 and 4.40+/-0.05, respectively; n=5; P>0.05). Zaprinast (10-5 M) a phosphodiesterase type V (PDE V) inhibitor, had no effect on the response to SPER-NO in vessels from eNOS WT or KO mice. 4. The NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 3x10-4 M) increased the potency of SPER-NO in aortas from WT mice (pEC50 6. 64+/-0.02 and 7.37+/-0.02 in the absence and presence of L-NAME, respectively; n=4; P<0.05). 5. In summary, there is increased sensitivity of vessels from eNOS KO animals to NO. Cyclic AMP-mediated dilatation is unchanged, consistent with a specific up-regulation of sGC - cyclic GMP signalling. The functional activity of cyclic GMP-dependent protein kinase (G-kinase) and PDE V was also unchanged, suggesting that sGC is the site of up-regulation. These alterations in the sensitivity of the sGC - cyclic GMP pathway might represent a mechanism for the dynamic regulation of NO bioactivity.     

Degradation Kinetics of BMP 777, an Elastase Inhibitor

Purpose. The objective was to evaluate the degradation profile of the elastase inhibitor DMP 777 and lay the foundation for formulation development. Methods. The pK_a was determined by potentiometric titration in mixed-aqueous solvents. The degradation kinetics were studied as a function of pH, buffer concentration, ionic strength, methanol concentration and temperature using a stability-indicating HPLC assay. The degradation products were identified by LC-MS, NMR, and by comparison with authentic samples. Results. The pK_a for the protonated piperazine nitrogen was estimated to be 7.04. The pH-rate profile is described by specific acid-, water-, and specific base-catalyzed pathways. The pH of maximum stability is in the range of 4 to 4.5 where water is the principal catalyst in the reaction. Buffer catalysis, primary salt effects and medium effects were observed. The proposed mechanism for acid catalyzed degradation is the rarely observed A_AL1 which involves alkyl-nitrogen heterolysis. The driving force for the reaction appears to lie in the stability of the benzylic carbocation. The proposed mechanism for base catalyzed degradation is B_AC2 which involves -lactam ring opening. The -lactam ring of DMP 777, a monolactam, appears to be as reactive as that in benzylpenicillin in the k _OH controlled region where a similar mechanism of hydrolysis should be operative. A contributing factor to this increased reactivity may lie in the reduced basicity of the -lactam nitrogen making it a good leaving group. Conclusions. The degradation profile indicates that development of a solution dosage form of DMP 777 with adequate shelf-life stability at room temperature is feasible.     

Prostate cancer old problems and new approaches

Rates of prostate cancer (PCa) have increased so dramatically over the last decade that the age adjusted incidence rate for PCa is now greater than that any other cancer among men in the United States. This review, published as a three part series, provides a state-of-art assessment of the PCa problem in its divergent aspects.Part 1 covers epidemiology, incidence and progression. Several epidemiological studies have demostrated that first degree male relatives of men with PCa are at increased risk of developing the disease. Familial and genetic factors as well as medical, anthropometric, dietary, hormonal and occupational factors involved in PCa are discussed. Postmortem examination of the prostate in men without evidence of PCa documented a high frequency of adenocarcinoma. Latent disease occurred as early as the second decade of life. Although there is no significant difference in incidence between Caucasian and African-American males, high grade prostatic intraepithelial neoplasia (HGPIN) is higher in the latter group. While dietary fat, androgens and certain environmental factors may be determinants for PCa, the exact mechanism of tumorigenesis is still relatively unknown. The current thinking of the role of genomic instability, chromosomal alterations, tumor suppressor genes and the androgen receptor are explored.     

Attitudes to smoking and smoking habits among hospital staff.

BACKGROUND: Health professionals should take an active role against smoking, so it is relevant to have information on their smoking habits and their attitudes towards smoking, especially with a view to identifying and offering help to those smokers who wish to stop. Staff in Llandough Hospital were surveyed to determine their smoking habits and attitudes, and the findings were compared with those of a similar survey at Llandough in 1987. METHODS: In October 1991 a questionnaire was sent to each member of staff employed half time or more requesting data on age, sex, department, smoking habit, attitudes to smoking in various areas of the hospital, and attitudes to access to smoking rest rooms for patients, staff, and visitors. Smokers were asked whether they would like to join a "quit smoking" group. Non-responders were sent a reminder four weeks later and all replies returned by 31 December 1991 were analysed. RESULTS: The response rate was 82%; of the respondents, 65% were non-smokers, 15% ex-smokers, and 20% current smokers. The prevalence of current smokers was 5% among doctors, 20% among nurses, 18% among administrative and clerical staff, and 40-42% among domestics, catering, and portering staff. Thirty eight per cent of responders wished smoking to be completely forbidden in all areas of the hospital and 90% in certain areas such as wards, offices, cafeteria, and laboratories. Nearly half wanted smoking to be allowed in rest rooms and over 60% wanted a 24 hour facility for smoking for staff, 56% for patients, and 44% for visitors. Only 39% of smokers wished to join a "quit smoking" support group. In comparison with the 1987 survey, the response rate in this study was higher (82% v 70%), the proportion of non-smokers had increased (65% v 59%), and more smokers wanted help (39% v 26%). Fewer wanted 24 hour access to smoking areas for staff and for visitors. CONCLUSION: This hospital should capitalise on these changes of attitude among staff and proceed more rapidly with the implementation of policies to further reduce smoking among staff, visitors, and patients. As a first step a smoking cessation counsellor has been appointed.     

Inhibition of cigarette smoke-related lipophilic DNA adducts in rat tissues by dietary oltipraz

The present study investigated the effects of dietary oltipraz on cigarette smoke-related lipophilic DNA adduct formation. Female Sprague- Dawley rats were exposed daily to sidestream cigarette smoke in a whole- body exposure chamber 6 h/day for 4 consecutive weeks. One group of rats was maintained on control diet while another group received the same diet supplemented with either a low (167 p.p.m.) or high (500 p.p.m.) dose of oltipraz, starting 1 week prior to initiation of smoke exposure until the end of the experiment. Analysis of lipophilic DNA adducts by the nuclease P1-mediated 32P-post-labeling showed up to five smoke-related adducts. Adduct no. 5 predominated in both the lung and the heart while adduct nos 3 and 2 predominated in the trachea and bladder, respectively. Quantitative analysis revealed that the total adduct level was the highest in lungs (270+/-68 adducts/10(10) nucleotides), followed by trachea (196+/-48 adducts/10(10) nucleotides), heart (141+/-22 adducts/10(10) nucleotides) and bladder (85+/-16 adducts/10(10) nucleotides). High dose oltipraz treatment reduced the adduct levels in lungs and bladder by >60%, while the reduction in lungs in the low-dose group was approximately 35%. In trachea, the effect of low and high dietary oltipraz on smoke DNA adduction was equivocal, while smoke-related DNA adducts in the heart were minimally inhibited by high-dose oltipraz. In a repeat experiment that employed a 3-fold lower dose of cigarette smoke, oltipraz (500 p.p.m.) was found to inhibit the formation of DNA adducts in rat lungs and trachea by 80 and 65%, respectively. These data clearly demonstrate a high efficacy of oltipraz in inhibiting the formation of cigarette smoke-induced DNA adducts in the target tissues.      

Histopathologic parameters of prognosis in cervical cancer – a review

Apart from clinical stage and lymph node status, acknowledged to be among the most powerful predictors of outcome in cervical cancer, the determination of prognosis and thereby the need for adjuvant therapy in surgically treated patients currently relies on a variety of histopathologic factors. The role of many of these is controversial. This may be because histopathology is genuinely lacking in sensitivity for predicting tumor behavior in vivo. There is, however, wide variation in histopathologic definitions and criteria. This is probably the major reason for both the lack of reproducibility in the reporting of certain factors and in their diminished value in predicting behavior. Tumor type, grade, vascular invasion, pattern of invasion, and depth are all extremely important prognostic indicators when used individually or as a part of a scoring system.     

Maternal mortality rates in the last eight years: A university hospital-based study from Turkey.

OBJECTIVE: To analyze the cause of changing maternal mortality ratios (MMRs) in a tertiary women's health center in Turkey in the last eight years. MATERIALS AND METHODS: Charts of patients seen between 1998 and 2005 were retrospectively reviewed. Statistical analysis was performed using the Chi-square test. The results were accepted to be significant when the p value was <0.05. RESULTS: During this period, 27 pregnancy-related deaths were identified via hospital death records. The MMR was found to have decreased in rate by approximately 50% from 822.2/100,000 live births in the previous report including the years 1978-1997 to 412.0/100,000 during the last eight years (p < 0.01). Pregnancy-induced hypertension was still the most frequent cause of maternal death. The decrease in MMR was due to the decrease in the ratio of maternal infection (26.4% in 1978-1997 to 7.4% in 1998-2005, p < 0.01). CONCLUSION: Although treatment in the antenatal care and health service has decreased maternal deaths, it was discovered that the MMR has not reached the optimum levels found in developed countries in the last eight years. Also the percentage of direct obstetric deaths (with the exception of those caused by infection) showed no change and was similar to that found in the previous report (1978-1997).