9892105
Evidence for multiple inducible cytochrome P450 isozymes in SENCAR mouse skin by pyridine.
Pyridine, an amphipathic solvent, is widely used in industry and is also a constituent of tobacco and its smoke. Since, in addition to inhalation and ingestion, pyridine is also readily absorbed through skin, we assessed the effect of skin application of pyridine on monooxygenase activities and cytochrome P450 (CYP) isozymes and CYP mRNA levels in the skin of SENCAR mice. Compared to controls, a single topical application of pyridine (30 or 50 mg/100 g body weight) resulted in induction of cutaneous 7-ethoxyresorufin O-deethylase, 7-pentoxyresorufin O-depentylase, and erythromycin N-demethylase activities. Pyridine treatment also resulted in an increase in reactivity with monoclonal antibodies directed against CYP 1A1, 2B1 and 3A. In Northern blot analysis, treatment of pyridine also showed a significant increase in mRNA for Cyp1a-1 in the skin. These data indicate that murine skin contains multiple inducible CYP isozymes, and that pyridine results in the induction of at least three families of CYP in murine skin.
46117096
ras protein p21 processing enzyme farnesyltransferase in chemical carcinogen-induced murine skin tumors.
Farnesylation of ras protein p21 is crucial for the protein's membrane localization, which is essential for its cell-transforming activity, which in turn is thought to be critical for the ultimate induction of cancer. The cytosolic enzyme farnesyltransferase plays a major role in posttranslational modification of p21, but the level of farnesyltransferase activity in mammalian tumors and its relationship to the processing of cytosolic p21 that leads to tumorigenesis are unknown. We report here that farnesyltransferase activity was significantly higher in chemical carcinogen-induced benign skin papillomas in SENCAR mice than in the epidermises of control animals. The enzyme is primarily epidermal in origin, and kinetic studies with cytosol from epidermis and papillomas showed that the reaction was linear with respect to time, substrate concentration, and protein content. Skin papillomas showed significantly elevated levels of both cytosolic and membrane-bound Ha-ras p21, whereas far lesser cytosolic and almost negligible amounts of membrane-bound p21 were present in the epidermis of control mice. There was a positive correlation between increased enzyme activity in papilloma cytosol and the processing of overexpressed cytosolic Ha-ras p21 for its localization to membrane.
6837472
Apoptosis is an early event during phthalocyanine photodynamic therapy-induced ablation of chemically induced squamous papillomas in mouse skin.
Photodynamic therapy (PDT) is a promising new modality to treat malignant neoplasms including superficial skin cancers. In our search for an ideal photosensitizer for PDT, Pc 4, a silicon phthalocyanine, has shown promising results both in in vitro assays and in implanted tumors. In this study we assessed the efficacy of Pc 4 PDT in the ablation of murine skin tumors; and the evidence for apoptosis during tumor ablation was also obtained. The Pc 4 was administered through tail vein injection to SENCAR mice bearing chemically induced squamous papillomas, and 24 h later the lesions were illuminated with an argon ion-pumped dye laser tuned at 675 nm for a total light dose of 135 J/cm2. Within 72-96 h, almost complete tumor shrinkage occurred; no tumor regrowth was observed up to 90 days post-PDT. As evident by nucleosome-size DNA fragmentation, appearance of apoptotic bodies in hematoxylin and eosin staining and direct immunoperoxidase detection of digoxigenin-labeled genomic DNA in sections, apoptosis was clearly evident 6 h post-PDT at which time tumor shrinkage was less than 30%. The apoptotic bodies, as evident by the condensation of chromatin material around the periphery of the nucleus and increased vacuolization of the cytoplasm, were also observed in electron microscopic studies of the tumor tissues following Pc 4 PDT. The extent of apoptosis was greater at 15 h than at 6 and 10 h post-PDT. Taken together, our results clearly show that Pc 4 may be an effective photosensitizer for PDT of nonmelanoma skin cancer, and that apoptosis is an early event during this process.
5785486
Identification of the site of photocross-linking formed in the absence of magnesium nucleotide from SH2 (Cys-697) in myosin subfragment 1 labeled with 4'-maleimidylbenzophenone.
The site of photocross-linking between Cys-697 (SH2), prelabeled with 4'-[14C]maleimidylbenzophenone, and the 50-kDa segment of myosin S1 on irradiation in the absence of nucleotide has been determined by isolation of the 20-50-kDa adduct and subsequent tryptic proteolysis. Isolation and partial sequencing of the radioactively labeled peptide indicate that the site of cross-linking is Arg-239. This result indicates that, in the absence of nucleotide, Arg-239 resides at about 1.0 nm from SH2 and, on the basis of the recent work of Sutoh and Hiratsuka (Sutoh, K. and Hiratsuka T. (1988) Biochemistry 27, 2964-2969) places Arg-239 at no more than 1.45 nm from either Lys-184 or Lys-189 of the nucleotide-binding "glycine-rich" loop prior to the binding of nucleotide.
35457752
Nordihydroguaiaretic acid, an inhibitor of lipoxygenase, also inhibits cytochrome P-450-mediated monooxygenase activity in rat epidermal and hepatic microsomes.
Nordihydroguaiaretic acid (NDGA), a plant lignan and phenolic antioxidant, is a known lipoxygenase inhibitor. In this study, we investigated the effect of NDGA on rat epidermal and hepatic monooxygenase activity and its interaction with rat hepatic microsomal cytochrome P-450. The addition of NDGA to epidermal microsomes prepared from control and 3-methylcholanthrene (3-MC)-pretreated rats and hepatic microsomal preparations from control, 3-MC-pretreated, and phenobarbital (PB)-pretreated rats resulted in a concentration-dependent inhibition of aryl hydrocarbon hydroxylase (AHH) and 7-ethoxyresorufin O-deethylase (ERD) activities. The 50% inhibitory dose for NDGA ranged from 4.1 x 10(-5) to 13.1 x 10(-5) M for AHH and ERD activities in these microsomal preparations. The addition of NDGA to hepatic microsomes prepared from PB-pretreated rats resulted in spectral changes characterized by absorbance maxima at 380 nm and minima at 414 nm, typical of type I binding difference spectra. It also showed time- and concentration-dependent inhibition of the binding of carbon monoxide to dithionite or NADPH-reduced cytochrome P-450. We speculate that perhaps hydroxyl groups present in NDGA play an important role in inhibiting the monooxygenase activity and suggest that NDGA may have potential as an antimutagen and/or anticarcinogen. Furthermore, caution must be exercised in elucidating the role of lipoxygenase in metabolic pathways based solely on the criterion of inhibition by NDGA.
37464296
Introduction to Special Issue on Molecular Basis for Cancer Prevention with Bioactive Food Components in Nutrition and Cancer--an International Journal.
The advance of technology and understanding of the process of cancer development suggests that the reported lesser incidence and death due to cancer in countries other than the Western and European countries might also be due to under- diagnosed and under-represented cases. Further, increases in life span as well as ignorance about the disease puts populations in South and South East Asian countries at higher risk to develop cancer. With the increasing rate of cancer incidence every year in non -Western countries, cancer is estimated to become the deadliest disease in coming decades. Conventional chemo- and radio-therapies during the past three decades have not been able to contain the disease, and also have serious side effects. Many natural agents, especially small molecules from plants are non-toxic, easily available and may have anticancer potential. Thus, screening phytochemicals as anticancer agents could be a better approach in cancer prevention and treatment. This chemoprevention approach may have translational significance for prevention and treatment of cancer. 
 
Therefore to emphasize the potential role of phytochemicals in cancer prevention and therapy, it was our privilege to host the International Symposium on Recent Advances in Cancer Research: Therapeutics to Chemoprevention, at Central University of Gujarat (CUG), Gandhinagar. The conference was co-organized by the University of Colorado Denver, USA; University of Pittsburgh, USA; University of Oklahoma, USA, during 8–9 February, 2012. Modern biological strategies, specifically the latest developments for the targeted prevention and treatment of cancer via dietary, natural and synthetic agents were discussed in detail. The symposium also emphasized the translational aspect of cancer chemoprevention strategies for various cancers. 
 
The symposium deliberations include the ideas for combinatorial chemoprevention by phytochemicals as a promising approach for cancer control and emerging trends for the use of herbal radio-modulators to sensitize the cancer cells for apoptotic cell death. Many bioactive phytochemicals such as silibinin, benzyl isothiocyanate, anthocyanidins, nexrutine, tocopherol, etc. were discussed for their in vivo efficacy in animal tumor models, associated mechanisms and translational potential. Targeting tumor microenvironment with small molecules was found promising and having translational potential for prostate and breast cancer chemoprevention. 
 
The novel work and ideas presented at the symposium were helpful in guiding the research orientation of scientists, especially the young researchers who will be benefitted at all levels of their career development. Since chemoprevention of cancer is becoming an attractive approach for controlling cancer, we felt that the deliberations of this symposium should reach to the wider section of the researchers. Therefore, it was planned to bring out a special issue on Molecular Basis for Cancer Prevention with Bioactive Food Components in Nutrition and Cancer – An International Journal. We appreciate the researchers for contributing their novel work and ideas to this special issue. We are grateful to the Editor of Nutrition and Cancer – An International Journal, for his initiative to bring out this special issue on this relevant topic. We believe that this volume will be enlightening for the researchers working in the area of cancer chemoprevention.
5792982
Therapeutic potential of Curcuma longa, the golden spice of India, in drug discovery for ophthalmic diseases
Background: Curcuma longa is among the most commonly used spices in India and other Asian countries. The herb has also been used in Ayurveda and other traditional systems of medicine for the prevention and treatment of a variety of ailments. Curcuminoids are the major chemical constituents of C. longa that are of medicinal importance. Today, a large body of scientific evidence exists to indicate potential therapeutic benefits of C. longa. Several preclinical and clinical studies have investigated the pharmacological properties of C. longa and results indicate strong therapeutic potential for anti-inflammatory, antioxidant, antibacterial, anticancer and many other properties. Objective: This review summarizes the scientific evidences showing possible benefits of C. longa in a variety of ophthalmic diseases. Conclusion: Although the putative mechanism(s), molecular targets and range of therapeutic applications have been researched widely, further investigations are needed to explore the true therapeutic potential and future of curcuminoids as novel drug molecules in ophthalmic diseases.
20123228
Selection of initial antihypertensive therapy, regimen design, and goal blood pressure.
Systolic and diastolic blood pressures (BPs) have a strong, continuous, graded, and etiologically significant positive association with cardiovascular disease outcomes. Small reductions in systolic and diastolic BP lead to large and proportionate reductions in ischemic heart disease, stroke, and vascular mortality. A recently reported meta-analysis of nearly a million people without pre-existing vascular disease and participating in clinical trials or observational studies analyzed the relationship between BP and cardiovascular mortality (1). A steep, direct log-linear relationship between systolic and diastolic BP was seen with mortality caused by stroke, ischemic heart disease, and other vascular diseases, including heart failure. The dose-response relationship is seen continuously until 89 years of age. Thus, even the very old have the same relationship between BP and vascular mortality. The million people meta-analysis also was unable to find a threshold at which BP reduction does not yield benefit. The lowest usual BP at any age associated with the best outcomes was 115/75 mmHg. The proportionality of risk reduction also reveals that 20 mmHg systolic BP reduction from 130 to 110 mmHg translates to the same risk reduction as from 180 to 160 mmHg. Vasan et al. (2) analyzed the relationship of high-normal BP with cardiovascular outcomes in men and women in the Framingham cohort. Four BP categories— optimal, normal, high-normal, and hypertension—were studied as defined by the Sixth Joint National Committee. High-normal BP was associated with increased cardiovascular events in both men and women. Even after adjusting for other cardiovascular risk factors (age, body mass index, total cholesterol, diabetes, smoking, and examination year), the risk of first major cardiovascular event was increased 40% in women and 20% in men per change in BP category. A continuous trend for cardiovascular disease across the 3 nonhypertensive BP categories was seen. The authors conclude, “A 20% overall absolute risk of CV events at 10 years currently defines the threshold for treatment of hypertension. In subjects 65 years age, the 10-year absolute risk exceeded 20% in men and approached this in women. Assuming a 25% risk reduction, the estimated number needed to treat over 5 years would be 28 men or 41 women.” These data show that no BP reduction is trivial, and the risk reduction is log-linear. Thus, if the baseline absolute risk is high, the reduction in BP needed to reduce cardiovascular outcomes will be evident with a smaller number of patients.
21916120
Treated hypertension and the white coat phenomenon: Office readings are inadequate measures of efficacy.
To better define the prevalence of white coat hypertension (WCH) among patients with type 2 diabetes mellitus and to estimate the magnitude of white coat effect (WCE), before and after antihypertensive therapy, we gathered data from an open-label forced-titration study of a combination of antihypertensive drugs that was titrated sequentially, in the order amlodipine, olmesartan, and hydrochlorothiazide, over an 18-week period among 187 patients with type 2 diabetes mellitus. WCH was defined as daytime ambulatory blood pressure (BP) of 135/85 mm Hg or less, but clinic BP of 140/90 mm Hg or more. WCE was obtained as the mean difference between clinic and daytime ambulatory BP. At baseline, the prevalence of WCH was 12%; all but one subject had WCE of >10/5 mm Hg. After treatment, the prevalence of WCH had increased to 39% (P < .001). In the overall population, at baseline, the mean (±SD) WCE for systolic BP was 10.4 ± 10.9 mm Hg and 3.7 ± 8.6 mm Hg for diastolic BP. After treatment, the reduction in systolic WCE was 3.01 ± 0.93 (SE; P < .0001); no reduction was seen for diastolic WCE. Among patients treated with amlodipine-olmesartan combination, WCE at baseline was 11 mm Hg systolic and was attenuated to -0.9 mm Hg. Among patients treated with amlodipine-olmesartan-hydrochlorothiazide combination, systolic WCE was similar at baseline (10.1 mm Hg) and at end of therapy (8.1 mm Hg). Mean systolic difference between dual and triple therapy of 9.9 mm Hg, SE 2.98 was significant (P < .001). The drop in diastolic WCE from 6.4 with dual therapy to -1.2 with triple therapy was also significant (mean difference 7.6, SE 2.2; P < .001). In conclusion, the prevalence of WCH increases three-fold with treatment as a result of fewer patients having sustained hypertension. Thus, out-of-office BP monitoring especially among treated hypertensive patients with type 2 diabetes is necessary to provide better assessment of overall BP and response to treatment.
6343189
Mechanisms of angiotensin converting enzyme inhibitor-induced IOP reduction in normotensive rats.
Angiotensin converting enzyme inhibitors (ACEIs) have been shown to lower intraocular pressure (IOP). Since, the ACEIs cause increased tissue prostaglandin levels, we hypothesized that the mechanisms of ACEI-induced IOP reduction have similarity with those of prostaglandin analogs. The present study investigated the involvement of matrix metalloproteinases (MMPs) and cytokine activity modulation as the underlying mechanisms of ACEI-induced ocular hypotension. The IOP lowering effect of single drop of enalaprilat dehydrate 1% was evaluated in rats pretreated with a broad spectrum MMP inhibitor or a cytokine inhibitor. Effect of angiotensin receptor blocker, losartan potassium 2%, was also studied to evaluate involvement of angiotensin II receptor type 1 (AT1) in IOP lowering effect of ACEI. Topical treatment with single drop of enalaprilat resulted in significant IOP reduction in treated eye with mean peak reduction 20.3% at 3h post-instillation. Treatment with losartan resulted in a peak IOP reduction of 13.3%, which was significantly lower than enalaprilat, indicating involvement of mechanisms in addition to AT1 blockade. Pretreatment with a broad spectrum MMP inhibitor or a cytokine inhibitor significantly attenuated the enalprilat-induced IOP reduction with mean peak IOP reduction of 11.2% and 13.6% respectively. The IOP-lowering effect of enalaprilat seems to be attributed to reduced angiotensin II type 1 receptor stimulation and modulation of MMP and cytokines activities.
30954752
Salt, salt sensitivity, and the endothelium: a pathway to discovery of molecular mechanisms.
See related article, pp 951–956

This issue of Hypertension contains a report of molecular mechanisms transducing dietary salt intake1 that may have broad clinical relevance. These molecular mechanisms are complex, but to begin to understand this study we have to understand the importance of dietary salt intake and salt sensitivity. This background will be discussed in some detail before discussing the molecular mechanisms.

Although cohort studies have called into question the role of dietary salt intake in causing hypertension,2 cause and effect relationships are most convincing when demonstrated using randomized clinical trials. It would be unethical to perform a randomized clinical trial in which the dietary intake of salt (sodium chloride) is increased for years in humans to observe an increase in blood pressure. However, such an experiment in primates has been performed by Denton et al,3 who studied in Gabon, Africa, 26 chimpanzees. Chimpanzees have a native diet that is vegetarian and is very high in potassium content. The baseline sodium intake in these primates was only 6 mEq/d; in contrast, that of K was 235 mEq/d. Blood pressure was measured in the 26 animals for 1 year. Subsequently, among half the animals, increasing amounts of salt (in increments of 5 g/d sodium) were added to a diet to a steady-state level of 15 g/d. This dietary intake was maintained for 16 months. After this period of dietary supplementation, the diet was switched to baseline and observations made for another 6 months. A dose–response relationship between salt supplementation and blood pressure increment was seen. With 15 g/d sodium supplementation for 67 weeks, the change from baseline in blood pressure was 33/10 mm Hg. In comparison, 5 g/d sodium supplementation for 19 weeks provoked blood pressure change of 12/0 mm Hg. Notably, plasma renin activity was reduced with salt …