40656023
Temperature-induced changes in the flexibility of the loop between SH1 (Cys-707) and SH3 (Cys-522) in myosin subfragment 1 detected by cross-linking.
The ability of dibromobimane to cross-link SH1 (Cys-707) in the 21-kDa C-terminal segment to SH3 (Cys-522) in the 50-kDa middle segment of the myosin S1 heavy chain has been examined as a function of nucleotide binding and temperature. The results obtained indicate that, while the reagent rapidly reacts with SH1 at both 25 and 4 degrees C, its ability to cross-link to SH3 is highly dependent on temperature. At 25 degrees C, substantial cross-linking from monofunctionally labeled SH1 to SH3 occurs, in agreement with recent work of Mornet, Ue, and Morales (1985, Proc. Natl. Acad. Sci, USA 82, 1658-1662) and of Ue (1987, Biochemistry 26, 1889-1894) and with their conclusion that a loop, allowing SH1 and SH3 to reside at the cross-linking span of dibromobimane, preexists in the protein. At 4 degrees C, however, negligible amounts of cross-linking are observed whether or not a nucleotide is present, despite indications that SH1 is labeled rapidly by the reagent at this temperature. The inability to form this cross-link is not due to an alternate cross-link between monofunctionally labeled SH1 and another thiol in the 21-kDa segment. These results indicate that this loop exists at 25 degrees C and does not exist (or exists only transiently) at the lower temperature.
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.
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.
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.
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.
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.
14660949
Dry-weight reduction in hypertensive hemodialysis patients (DRIP): a randomized, controlled trial.
Volume excess is thought to be important in the pathogenesis of hypertension among hemodialysis patients. To determine whether additional volume reduction will result in improvement in blood pressure (BP) among hypertensive patients on hemodialysis and to evaluate the time course of this response, we randomly assigned long-term hypertensive hemodialysis patients to ultrafiltration or control groups. The additional ultrafiltration group (n=100) had the dry weight probed without increasing time or duration of dialysis, whereas the control group (n=50) only had physician visits. The primary outcome was change in systolic interdialytic ambulatory BP. Postdialysis weight was reduced by 0.9 kg at 4 weeks and resulted in -6.9 mm Hg (95% CI: -12.4 to -1.3 mm Hg; P=0.016) change in systolic BP and -3.1 mm Hg (95% CI: -6.2 to -0.02 mm Hg; P=0.048) change in diastolic BP. At 8 weeks, dry weight was reduced 1 kg, systolic BP changed -6.6 mm Hg (95% CI: -12.2 to -1.0 mm Hg; P=0.021), and diastolic BP changed -3.3 mm Hg (95% CI: -6.4 to -0.2 mm Hg; P=0.037) from baseline. The Mantel-Hanzel combined odds ratio for systolic BP reduction of > or =10 mm Hg was 2.24 (95% CI: 1.32 to 3.81; P=0.003). There was no deterioration seen in any domain of the kidney disease quality of life health survey despite an increase in intradialytic signs and symptoms of hypotension. The reduction of dry weight is a simple, efficacious, and well-tolerated maneuver to improve BP control in hypertensive hemodialysis patients. Long-term control of BP will depend on continued assessment and maintenance of dry weight.
10037944
Mandibular reconstruction using extraoral trifocal bone transport: report of a case using a new device.
A newly designed mandibular stabilization and transport distraction system is an extraoral assembly of a half-elliptical rod, with movable clamp attachments that serves the dual purpose of stabilization and transport distraction osteogenesis of mandibular segmental defects. The rod is threaded and made of stainless steel, and it conforms to the shape of the human mandible. Mandibular stabilization and bone transport are accomplished with the help of different assemblies that are attached onto this rod. There are 3 different assemblies having separate functions but achieving the same goals of mandibular stabilization and bone transport. All the assemblies have a common base unit that moves on threads of the curved rod in a graduated manner, controlled by a spanner. One full turn of 360° moves the assembly by a distance of 1 mm. The first assembly is the stabilization assembly, which helps in the rigid fixation of the frame to the mandible by use of at least 2 clamp units on either side of the midline. It helps in stabilization of the mandibular segments in an anatomic position. The bone transport assembly consists of 1 or 2 moveable clamp assemblies that are fixed at 1 end to the transport disc of the mandible, while the base unit assembly glides and engages on the threads of the distraction rod. This allows bone regeneration and laying down of new bone in the natural position along the path of movement of the transport disc in a curvilinear manner. This system allows mandibular regenera-
19975781
Cloning, high level expression, purification, and crystallization of the full length Clostridium botulinum neurotoxin type E light chain.
The catalytic activity of the highly potent botulinum neurotoxins are confined to their N-terminal light chains ( approximately 50kDa). A full-length light chain for the type E neurotoxin with a C-terminal 6x His-tag, BoNT/E-LC, has been cloned in a pET-9c vector and over-expressed in BL21 (DE3) cells. BoNT/E-LC was purified to homogeneity by affinity chromatography on Ni-NTA agarose followed by exclusion chromatography using a Superdex-75 sizing column. The purified protein has very good solubility and can be stored stably at -20 degrees C; however, it seems to undergo auto-proteolysis when stored at temperature #10878;4-10 degrees C. BoNT/E-LC is active on its natural substrate, the synaptosomal associated 25kDa protein, SNAP-25, indicating that it retains a native-like conformation and therefore can be considered as a useful tool in studying the structure/function of the catalytic light chain. Recombinant BoNT/E-LC has been crystallized under five different conditions and at various pHs. Crystals diffract to better than 2.1A.
22379602
Dialysis dose and the diagnosis of hypertension in hemodialysis patients.
OBJECTIVE
To determine whether simultaneous consideration of pre and postdialysis blood pressure (BP) can improve the prediction of interdialytic ambulatory BP in hemodialysis patients, we analyzed BP obtained before and after dialysis using routine or standardized methods and by self-measurement at home in 104 hemodialysis patients. Evidence for effect modification was tested for several plausible demographic, clinical and laboratory factors.


RESULTS
Postdialysis BP when considered jointly with predialysis BP improved the diagnostic performance of standardized dialysis unit BP measurements [receiver operating characteristic (ROC) area under the curve (AUC) 0.91 for joint, 0.85 for prehemodialysis ROC (P=0.01 for difference in AUC)]. A trend to improvement existed in ROC AUC with routine dialysis unit BP measurement [ROC AUC 0.88 for joint, 0.82 for prehemodialysis ROC (P=0.055 for difference in AUC)]. Dialysis dose measured by urea reduction ratio was a strong effect modifier for the determination of hypertension by routine (P=0.012) and standardized (P=0.002) dialysis unit BP measurements. This effect modification was not seen with home BP (P=0.26).


CONCLUSION
Simultaneous consideration of predialysis and postdialysis BPs obtained over 2 weeks can improve the diagnosis of hypertension in hemodialysis patients. Dialysis dose may significantly influence the diagnosis of hypertension when dialysis unit BPs are used.
21184188
Temperature sensitivity and fluorescence detection.
Fluorescence detectors are about three orders of magnitude more sensitive and specific making them ideal for trace analysis and complex sample matrices. However, temperature dependence of the signal is a disadvantage to fluorescence detectors. We have previously reported degradation of malondialdehyde (MDA)-thiobarbituric acid (TBA) adduct at room temperature. The present experiments tested the notion that the detector response may be blunted due to increase in temperature over time. Repeated injections of the same standard curve over 4 h found a significant effect of time on the slopes of peak area-concentration curves. When the samples were iced and injected alternating with ambient temperature standard curve samples, no differences in slopes were seen between iced and ambient temperature samples. Cooling the housing of the fluorescence lamp significantly increased the fluorescence in the samples. Fluorescence increased 2.5% (95% confidence interval, 1.5-3.6%) for each 1 degrees C fall in temperature. MDA-TBA adduct remained stable at room temperature. Since the fluorescence signal is temperature sensitive, letting the detector warm up for 2 h to obtain a steady temperature is more likely to give reproducible results compared to a detector that has not warmed up. These results have implications for other applications utilizing fluorescence detectors.