Identification and inhibition of the ICE/CED-3 protease necessary for mammalian apoptosis

The protease responsible for the cleavage of poly(ADP-ribose) polymerase and necessary for apoptosis has been purified and characterized. This enzyme, named apopain, is composed of two subunits of relative molecular mass (M(r)) 17K and 12K that are derived from a common proenzyme identified as CPP32. This proenzyme is related to interleukin-1 beta-converting enzyme (ICE) and CED-3, the product of a gene required for programmed cell death in Caenorhabditis elegans. A potent peptide aldehyde inhibitor has been developed and shown to prevent apoptotic events in vitro, suggesting that apopain/CPP32 is important for the initiation of apoptotic cell death.

North American and European porcine reproductive and respiratory syndrome viruses differ in non-structural protein coding regions

Although North American and European serotypes of porcine reproductive and respiratory syndrome virus (PRRSV) are recognized, only the genome of the European Lelystad strain (LV) has been sequenced completely. Here, the genome of the pathogenic North American PRRSV isolate 16244B has been sequenced and compared with LV. The genomic organization of 16244B was the same as LV but with only 63.4% nucleotide identity. The 189 nucleotide 5' non-coding region (NCR) of 16244B was distinct from the LV NCR, with good conservation (83%) only over a 43 base region immediately upstream of open reading frame (ORF) 1a. Major differences were found in the region encoding the non-structural part of the ORF1a polyprotein, which shared only 47% amino acid identity over 2503 residues of the six non-structural proteins (Nsps) encoded. Nsp2, thought to have a species-specific function, showed the greatest divergence, sharing only 32% amino acid identity with LV and containing 120 additional amino acids in the central region. Nsps encoded by the 5'-proximal and central regions of ORF1b had from 66 to 75% amino acid identity; however, the carboxy-terminal protein CP4 was distinct (42% identity). The ORF 1a-1b frameshift region of 16244B had 98% nucleotide identity with LV. Consistent with previous reports for North American isolates, the six structural proteins encoded were 58 to 79% identical to LV proteins. The 3' NCR (150 nucleotides) was 76% identical between isolates. These genomic differences confirm the presence of distinct North American and European PRRSV genotypes.

Addition of docetaxel to hormonal therapy in low- and high-burden metastatic hormone sensitive prostate cancer: long-term survival results from the STAMPEDE trial

BACKGROUND

STAMPEDE has previously reported that the use of upfront docetaxel improved overall survival (OS) for metastatic hormone naïve prostate cancer patients starting long-term androgen deprivation therapy. We report on long-term outcomes stratified by metastatic burden for M1 patients.

METHODS

We randomly allocated patients in 2 : 1 ratio to standard-of-care (SOC; control group) or SOC + docetaxel. Metastatic disease burden was categorised using retrospectively-collected baseline staging scans where available. Analysis used Cox regression models, adjusted for stratification factors, with emphasis on restricted mean survival time where hazards were non-proportional.

RESULTS

Between 05 October 2005 and 31 March 2013, 1086 M1 patients were randomised to receive SOC (n = 724) or SOC + docetaxel (n = 362). Metastatic burden was assessable for 830/1086 (76%) patients; 362 (44%) had low and 468 (56%) high metastatic burden. Median follow-up was 78.2 months. There were 494 deaths on SOC (41% more than the previous report). There was good evidence of benefit of docetaxel over SOC on OS (HR = 0.81, 95% CI 0.69-0.95, P = 0.009) with no evidence of heterogeneity of docetaxel effect between metastatic burden sub-groups (interaction P = 0.827). Analysis of other outcomes found evidence of benefit for docetaxel over SOC in failure-free survival (HR = 0.66, 95% CI 0.57-0.76, P < 0.001) and progression-free survival (HR = 0.69, 95% CI 0.59-0.81, P < 0.001) with no evidence of heterogeneity of docetaxel effect between metastatic burden sub-groups (interaction P > 0.5 in each case). There was no evidence that docetaxel resulted in late toxicity compared with SOC: after 1 year, G3-5 toxicity was reported for 28% SOC and 27% docetaxel (in patients still on follow-up at 1 year without prior progression).

CONCLUSIONS

The clinically significant benefit in survival for upfront docetaxel persists at longer follow-up, with no evidence that benefit differed by metastatic burden. We advocate that upfront docetaxel is considered for metastatic hormone naïve prostate cancer patients regardless of metastatic burden.

Cellulose-based hydrogel materials: chemistry, properties and their prospective applications

Hydrogels based on cellulose comprising many organic biopolymers including cellulose, chitin, and chitosan are the hydrophilic material, which can absorb and retain a huge proportion of water in the interstitial sites of their structures. These polymers feature many amazing properties such as responsiveness to pH, time, temperature, chemical species and biological conditions besides a very high-water absorption capacity. Biopolymer hydrogels can be manipulated and crafted for numerous applications leading to a tremendous boom in research during recent times in scientific communities. With the growing environmental concerns and an emergent demand, researchers throughout the globe are concentrating particularly on naturally derived hydrogels due to their biocompatibility, biodegradability and abundance. Cellulose-based hydrogels are considered as useful biocompatible materials to be used in medical devices to treat, augment or replace any tissue, organ, or help function of the body. These hydrogels also hold a great promise for applications in agricultural activity, as smart materials and some other useful industrial purposes. This review offers an overview of the recent and contemporary research regarding physiochemical properties of cellulose-based hydrogels along with their applications in multidisciplinary areas including biomedical fields such as drug delivery, tissue engineering and wound healing, healthcare and hygienic products as well as in agriculture, textiles and industrial applications as smart materials.

Molecular cloning and pro-apoptotic activity of ICErelII and ICErelIII, members of the ICE/CED-3 family of cysteine proteases

Cysteine proteases related to mammalian interleukin-1 beta-converting enzyme (ICE) and the nematode cell death abnormal ced-3 gene product have been implicated in the effector mechanism of apoptotic cell death. Two novel members of this new family of ICE/CED-3-related proteases, designated ICErel-II and ICErel-III, were cloned from human monocytic cells. Both were highly homologous to human ICE (52% identical) and CED-3 (25% identical) and both contained the absolutely conserved pentapeptide sequence Gln-Ala-Cys-Arg-Asp containing the catalytic cysteine residue. Other structural motifs that were comparable with ICE suggest that ICErel-II and ICErel-III are also synthesized as larger proenzymes which are proteolytically processed to form heterodimeric active enzymes. Pro-interleukin-1 beta processing activity could not be detected in cells transfected with ICErel-II or ICErel-III, but pro-domain-less truncated forms of ICErel-II and ICErel-III were capable of effectively inducing fibroblast apoptosis. ICErel-II and ICErel-III may, therefore, participate in proteolytic events culminating in the apoptotic death of human cells.

HSP90 interacts with and regulates the activity of heat shock factor 1 in Xenopus oocytes

Transcriptional activation of heat shock genes is a reversible and multistep process involving conversion of inactive heat shock factor 1 (HSF1) monomers into heat shock element (HSE)-binding homotrimers, hyperphosphorylation, and further modifications that induce full transcriptional competence. HSF1 is controlled by multiple regulatory mechanisms, including suppression by additional cellular factors, physical interactions with HSP70, and integration into different cellular signaling cascades. However, the signaling mechanisms by which cells respond to stress and control the HSF1 activation-deactivation pathway are not known. Here we demonstrate that HSP90, a cellular chaperone known to regulate several signal transduction molecules and transcription factors, functions in the regulation of HSF1. The existence of HSF1-HSP90 heterocomplexes was shown by coimmunoprecipitation of HSP90 with HSF1 from unshocked and heat-shocked nuclear extracts, recognition of HSF1-HSE complexes in vitro by using HSP90 antibodies (Abs), and recognition of HSF1 in vivo by HSP90 Abs microinjected directly into oocyte nuclei. The functional impact of HSP90-HSF1 interactions was analyzed by using two strategies: direct nuclear injection of HSP90 Abs and treatment of cells with geldanamycin (GA), an agent that specifically blocks the chaperoning activity of HSP90. Both HSP90 Abs and GA delayed the disassembly of HSF1 trimers during recovery from heat shock and specifically inhibited heat-induced transcription from a chloramphenicol acetyltransferase reporter construct under control of the hsp70 promoter. HSP90 Abs activated HSE binding in the absence of heat shock, an effect that could be reversed by subsequent injection of purified HSP90. GA did not activate HSE binding under nonshock conditions but increased the quantity of HSE binding induced by heat shock. On the basis of these findings and the known properties of HSP90, we propose a new regulatory model in which HSP90 participates in modulating HSF1 at different points along the activation-deactivation pathway, influencing the interconversion between monomeric and trimeric conformations as well as transcriptional activation. We also put forth the hypothesis that HSP90 links HSF1 to cellular signaling molecules coordinating the stress response.

Influenza virus assembly: effect of influenza virus glycoproteins on the membrane association of M1 protein

Influenza virus matrix protein (M1), a critical protein required for virus assembly and budding, is presumed to interact with viral glycoproteins on the outer side and viral ribonucleoprotein on the inner side. However, because of the inherent membrane-binding ability of M1 protein, it has been difficult to demonstrate the specific interaction of M1 protein with hemagglutinin (HA) or neuraminidase (NA), the influenza virus envelope glycoproteins. Using Triton X-100 (TX-100) detergent treatment of membrane fractions and floatation in sucrose gradients, we observed that the membrane-bound M1 protein expressed alone or coexpressed with heterologous Sendai virus F was totally TX-100 soluble but the membrane-bound M1 protein expressed in the presence of HA and NA was predominantly detergent resistant and floated to the top of the density gradient. Furthermore, both the cytoplasmic tail and the transmembrane domain of HA facilitated binding of M1 to detergent-resistant membranes. Analysis of the membrane association of M1 in the early and late phases of the influenza virus infectious cycle revealed that the interaction of M1 with mature glycoproteins which associated with the detergent-resistant lipid rafts was responsible for the detergent resistance of membrane-bound M1. Immunofluorescence analysis by confocal microscopy also demonstrated that, in influenza virus-infected cells, a fraction of M1 protein colocalized with HA and associated with the HA in transit to the plasma membrane via the exocytic pathway. Similar results for colocalization were obtained when M1 and HA were coexpressed and HA transport was blocked by monensin treatment. These studies indicate that both HA and NA interact with influenza virus M1 and that HA associates with M1 via its cytoplasmic tail and transmembrane domain.

ATR/ATM-mediated phosphorylation of human Rad17 is required for genotoxic stress responses

Genotoxic stress triggers the activation of checkpoints that delay cell-cycle progression to allow for DNA repair. Studies in fission yeast implicate members of the Rad family of checkpoint proteins, which includes Rad17, Rad1, Rad9 and Hus1, as key early-response elements during the activation of both the DNA damage and replication checkpoints. Here we demonstrate a direct regulatory linkage between the human Rad17 homologue (hRad17) and the checkpoint kinases, ATM and ATR. Treatment of human cells with genotoxic agents induced ATM/ATR-dependent phosphorylation of hRad17 at Ser 635 and Ser 645. Overexpression of a hRad17 mutant (hRad17AA) bearing Ala substitutions at both phosphorylation sites abrogated the DNA-damage-induced G2 checkpoint, and sensitized human fibroblasts to genotoxic stress. In contrast to wild-type hRad17, the hRad17AA mutant showed no ionizing-radiation-inducible association with hRad1, a component of the hRad1-hRad9-hHus1 checkpoint complex. These findings demonstrate that ATR/ATM-dependent phosphorylation of hRad17 is a critical early event during checkpoint signalling in DNA-damaged cells.

Detection of Vibrio cholerae O1 in the aquatic environment by fluorescent-monoclonal antibody and culture methods

Vibrio cholerae O1 in plankton samples collected from ponds and rivers between February 1987 and January 1990 in Matlab, Bangladesh, was detected by the fluorescent-monoclonal antibody (FA) technique. Samples were collected at sites which were monitored fortnightly (fixed sites) as well as at sites that were part of a case-control study. FA results were compared with those obtained by conventional culture methods (CM). A total of 876 samples were collected; V. cholerae O1 was detected in 563 samples (64.27%) by the FA method and in 3 samples (0.34%) by CM. Of the fixed-site plankton samples, 439 (63.62%) were positive by FA and none were positive by CM. Of the 93 case sites sampled on the day after the occurrence of a case of cholera, 73 (78.49%) were positive for V. cholerae O1 by FA and 3 (3.2%) were positive by CM. In comparison, of the 93 first-day sample collections at control sites at the time a case of cholera occurred, only 51 (54.83%) were positive by FA and none were positive by CM. From the data, it is concluded that V. cholerae O1 is present throughout the year in the ponds and rivers of Bangladesh that were examined in this study and that V. cholerae can be detected by FA but not always by CM. The FA procedure was found to be very useful in detecting V. cholerae in plankton, with which it was associated and often occurred in large numbers in the nonculturable stage. Thus, studies investigating the significance of the role of environmental factors in the epidemiology of cholera can be performed effectively by using FA. Such studies are in progress.

Towards the routine use of brain imaging to aid the clinical diagnosis of disorders of consciousness

Clinical audits have highlighted the many challenges and dilemmas faced by clinicians assessing persons with disorders of consciousness (vegetative state and minimally conscious state). The diagnostic decision-making process is highly subjective, dependent upon the skills of the examiner and invariably dictated by the patients' ability to move or speak. Whilst a considerable amount has been learnt since Jennett and Plum coined the term 'vegetative state', the assessment process remains largely unchanged; conducted at the bedside, using behavioural assessment tools, which are susceptible to environmental and physiological factors. This has created a situation where the rate of misdiagnosis is unacceptably high (up to 43%). In order to address these problems, various functional brain imaging paradigms, which do not rely upon the patient's ability to move or speak, have been proposed as a source of additional information to inform the diagnostic decision making process. Although accumulated evidence from brain imaging, particularly functional magnetic resonance imaging (fMRI), has been encouraging, the empirical evidence is still based on relatively small numbers of patients. It remains unclear whether brain imaging is capable of informing the diagnosis beyond the behavioural assessment and whether brain imaging has any prognostic utility. In this study, we describe the functional brain imaging findings from a group of 41 patients with disorders of consciousness, who undertook a hierarchical speech processing task. We found, contrary to the clinical impression of a specialist team using behavioural assessment tools, that two patients referred to the study with a diagnosis of vegetative state did in fact demonstrate neural correlates of speech comprehension when assessed using functional brain imaging. These fMRI findings were found to have no association with the patient's behavioural presentation at the time of investigation and thus provided additional diagnostic information beyond the traditional clinical assessment. Notably, the utility of brain imaging was further underlined by the finding that the level of auditory processing revealed by functional brain imaging, correlated strongly (rs = 0.81, P < 0.001) with the patient's subsequent behavioural recovery, 6 months after the scan, suggesting that brain imaging may also provide valuable prognostic information. Although further evidence is required before consensus statements can be made regarding the use of brain imaging in clinical decision making for disorders of consciousness, the results from this study clearly highlight the potential of imaging to inform the diagnostic decision-making process for persons with disorders of consciousness.

Safety and tolerability of Transcutaneous Vagus Nerve stimulation in humans; a systematic review

BACKGROUND

Transcutaneous Vagus Nerve stimulation (tVNS) may be an alternative to surgically implanted VNS for epilepsy and other diseases. However, its safety and tolerability profile is unclear.

OBJECTIVE

We performed a systematic review of treatment harms from tVNS in humans.

METHODS

A systematic published and grey literature search was carried out to identify studies which deployed tVNS in human subjects. Study authors were contacted for safety/tolerability data if these were not available in the publication. Databases were searched from 1966 to May 2017. We noted study type, population, stimulation parameters, type and prevalence of side effects and/or serious adverse events (SAE). We also noted whether side effects/SAE were considered to be related to the tVNS and the proportion of participants dropping out of studies due to side effects.

RESULTS

51 studies were included comprising a total of 1322 human subjects receiving tVNS. The most common side effects were: local skin irritation from electrode placement (240 participants, 18.2%), headache (47, 3.6%) and nasopharyngitis (23, 1.7%). Whilst heterogeneity in overall side effect event rates between studies was not accounted for by the frequency (Hz) or pulse width (ms) of stimulation, a minority (35 participants (2.6%)) dropped out of studies due to side effects. Overall, 30 SAE occurred but only 3 were assessed by the relevant researchers to be possibly caused by tVNS.

CONCLUSION

tVNS is safe and well tolerated at the doses tested in research studies to date.

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

BACKGROUND

80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality.

METHODS

This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494.

FINDINGS

Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70-8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39-8·80) and upper-middle-income countries (2·06, 1·11-3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26-11·59) and upper-middle-income countries (3·89, 2·08-7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications.

INTERPRETATION

Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications.

FUNDING

National Institute for Health Research Global Health Research Unit.

Oxygen free radicals and systemic autoimmunity

Reactive oxygen species generated during various metabolic and biochemical reactions have multifarious effects that include oxidative damage to DNA leading to various human degenerative and autoimmune diseases. The highly reactive hydroxy radical (*OH) can interact with chromatin and result in a wide range of sugar and base-derived products, DNA-protein cross-links and strand breaks. Studies from our laboratory have demonstrated that after modification the DNA becomes highly immunogenic and the induced antibodies exhibit variable antigen-binding characteristics. Systemic lupus erythematosus, a prototype autoimmune disease, is characterized by the presence of autoantibodies to multiple nuclear antigens. The detection of 8-hydroxyguanosine in the immune complex derived DNA of systemic lupus erythematosus patients reinforces the evidence that reactive oxygen species may be involved in its pathogenesis. Increased apoptosis and decreased clearance of apoptotic cells as observed in systemic lupus erythematosus (SLE) might well be a contributory factor in systemic autoimmunity. Clinically, titres of autoantibodies are closely related to the degree of renal inflammation. Anti-DNA antibodies may combine with circulating antigen and contribute to the deposition of immune complexes in renal glomeruli.

Multiple components of the HSP90 chaperone complex function in regulation of heat shock factor 1 In vivo

Rapid and transient activation of heat shock genes in response to stress is mediated in eukaryotes by the heat shock transcription factor HSF1. It is well established that cells maintain a dynamic equilibrium between inactive HSF1 monomers and transcriptionally active trimers, but little is known about the mechanism linking HSF1 to reception of various stress stimuli or the factors controlling oligomerization. Recent reports have revealed that HSP90 regulates key steps in the HSF1 activation-deactivation process. Here, we tested the hypothesis that components of the HSP90 chaperone machine, known to function in the folding and maturation of steroid receptors, might also participate in HSF1 regulation. Mobility supershift assays using antibodies against chaperone components demonstrate that active HSF1 trimers exist in a heterocomplex with HSP90, p23, and FKBP52. Functional in vivo experiments in Xenopus oocytes indicate that components of the HSF1 heterocomplex, as well as other components of the HSP90 cochaperone machine, are involved in regulating oligomeric transitions. Elevation of the cellular levels of cochaperones affected the time of HSF1 deactivation during recovery: attenuation was delayed by immunophilins, and accelerated by HSP90, Hsp/c70, Hip, or Hop. In immunotargeting experiments with microinjected antibodies, disruption of HSP90, Hip, Hop, p23, FKBP51, and FKBP52 delayed attenuation. In addition, HSF1 was activated under nonstress conditions after immunotargeting of HSP90 and p23, evidence that these proteins remain associated with HSF1 monomers and function in their repression in vivo. The remarkable similarity of HSF1 complex chaperones identified here (HSP90, p23, and FKBP52) and components in mature steroid receptor complexes suggests that HSF1 oligomerization is regulated by a foldosome-type mechanism similar to steroid receptor pathways. The current evidence leads us to propose a model in which HSF1, HSP90 and p23 comprise a core heterocomplex required for rapid conformational switching through interaction with a dynamic series of HSP90 subcomplexes.

Measuring soccer skill performance: a review

The ability to execute skilled movement patterns efficiently and effectively is the most important aspect of soccer performance and players must apply cognitive, perceptual and motor skills to rapidly changing situations. There have been attempts to measure these parameters for talent identification (or development) purposes and skill acquisition and intervention research; the aim of this review is to examine the strengths and limitations of these tests. High levels of perceptual and cognitive skill are characteristics of those players who are able look in the right places for information and process this information efficiently before deciding on a suitable course of action. The motor skills required to successfully control, pass, dribble and shoot the ball at goal are fundamental skills of the soccer player and a variety of methods have been used to measure these aspects. The tests mentioned in this review vary in their complexity and the type of skill(s) they purport to measure. The assessment of choice must come down to a number of factors including cost, available time and space, number of athletes in the cohort and experience of researchers. Furthermore, consideration must be given to the aim(s) of the research/assessment and issues relating to validity and reliability.

Antitumor activity of curcumin is mediated through the induction of apoptosis in AK-5 tumor cells

Curcumin, the yellow pigment of turmeric (Curcuma longa), used commonly as a spice, has been shown to possess anticarcinogenic activity. Curcumin inhibited AK-5 tumor growth and induced apoptosis in AK-5 cells. Curcumin induced apoptosis is mediated through the activation of caspase-3, which is specifically inhibited by the tetrapeptide Ac-DEVD-CHO. In addition, curcumin induced tumor cell death is caused through the generation of reactive oxygen intermediates which is inhibited by N-acetyl-L-cysteine. Our studies suggest that the apoptotic process induced by curcumin is the mechanism mediating AK-5 tumor cell death.

The effects of the ideal of female beauty on mood and body satisfaction

OBJECTIVE

The present study examined changes in women's mood states resulting from their viewing pictures in fashion magazines of models who represent a thin ideal.

METHOD

Female university students completed the Profile of Mood States (POMS), the Body Parts Satisfaction Scale (BPSS), and the Eating Disorder Inventory (EDI). They were then exposed to 20 slides; the experimental group (N = 51) viewed images of female fashion models and a control group (N = 67) viewed slides containing no human figures. All subjects then completed the POMS and the BPSS again.

RESULTS

Women were more depressed (R2 = 0.745, p < .05) and more angry (R2 = 0.73, p < .01) following exposure to slides of female fashion models.

DISCUSSION

Viewing images of female fashion models had an immediate negative effect on women's mood. This study, therefore, supports the hypothesis that media images do play a role in disordered eating.

Characterization of the Streptomyces peucetius ATCC 29050 genes encoding doxorubicin polyketide synthase

The dps genes of Streptomyces peucetius, encoding daunorubicin (DNR)-doxorubicin (DXR) polyketide synthase (PKS), are largely within an 8.7-kb region of DNA that has been characterized by Southern analysis, and gene sequencing, mutagenesis and expression experiments. This region contains nine ORFs, many of whose predicted products are homologous to known PKS enzymes. Surprisingly, the gene encoding the DXR PKS acyl carrier protein is not in this region, but is located about 10 kb distant from the position it usually occupies in other gene clusters encoding type-II PKS. An in-frame deletion in the dpsB gene, encoding a putative subunit of the DXR PKS, resulted in loss of production of DXR and the known intermediates of its biosynthetic pathway, confirming that this gene and, by implication, the adjacent dps genes are required for DXR biosynthesis. This was verified by expression of the dps genes in the heterologous host, Streptomyces lividans, which resulted in the production of aklanonic acid, an early intermediate of DXR biosynthesis.

Alginate microspheres of isoniazid for oral sustained drug delivery

In the present study, spherical microspheres able to prolong the release of INH were produced by a modified emulsification method, using sodium alginate as the hydrophilic carrier. The shape and surface characteristics were determined by scanning electron microscopy using gold sputter technique. Particle sizes of both placebo and drug-loaded formulations were measured by SEM and the particle size distribution was determined by an optical microscope. The physical state of the drug in the formulation was determined by differential scanning calorimetry (DSC). The release profiles of INH from microspheres were examined in simulated gastric fluid (SGF pH 1.2) and simulated intestinal fluid (SIF pH 7.4). Gamma-scintigraphic studies were carried out to determine the location of microspheres on oral administration and the extent of transit through the gastrointestinal tract (GIT). The microspheres had a smoother surface and were found to be discreet and spherical in shape. The particles were heterogeneous with the maximum particles of an average size of 3.719mum. Results indicated that the mean particle size of the microspheres increased with an increase in the concentration of polymer and the cross-linker as well as the cross-linking time. The entrapment efficiency was found to be in the range of 40-91%. Concentration of the cross-linker up to 7.5% caused increase in the entrapment efficiency and the extent of drug release. Optimized isoniazid-alginate microspheres were found to possess good bioadhesion (72.25+/-1.015%). The bioadhesive property of the particles resulted in prolonged retention in the small intestine. Microspheres could be observed in the intestinal lumen at 4h and were detectable in the intestine 24h post-oral administration, although the percent radioactivity had significantly decreased (t(1/2) of (99m)Tc=4-5h). Increased drug loading (91%) was observed for the optimized formulation suggesting the efficiency of the method. Nearly 26% of INH was released in SGF pH 1.2 in 6h and 71.25% in SIF pH 7.4 in 30h. No significant drug-polymer interactions were observed in FT-IR studies. Dissolution and gamma-scintigraphy studies have shown promising results proving the utility of the formulation for enteric drug delivery.

Glycogen synthase kinase 3beta negatively regulates both DNA-binding and transcriptional activities of heat shock factor 1

Stress activation of heat shock factor (HSF1) involves the conversion of repressed monomers to DNA-binding homotrimers with increased transcriptional capacity and results in transcriptional up-regulation of the heat shock protein (hsp) gene family. Cells tightly control the activity of HSF1 through interactions with hsp90 chaperone complexes and through integration into a number of different signaling cascades. A number of studies have shown that HSF1 transcriptional activity is negatively regulated by constitutive phosphorylation in the regulatory domain by glycogen synthase kinase (GSK3) isoforms alpha/beta. However, previous studies have not examined the ability of GSK3 to regulate the DNA-binding activity of native HSF1 in vivo under heat shock conditions. Here we show that GSK3beta inhibits both DNA-binding and transcriptional activities of HSF1 in heat-shocked cells. Specific inhibition of GSK3 increased the levels of DNA binding and transcription after heat shock and delayed the attenuation of HSF1 during recovery. In contrast, the overexpression of GSK3beta resulted in significant reduction in heat-induced HSF1 activities. These results confirm the role of GSK3beta as a negative regulator of HSF1 transcription in cells during heat shock and demonstrate for the first time that GSK3beta functions to repress DNA binding.

Prevalence of adrenal carcinoma among incidentally discovered adrenal masses. A retrospective study from 1989 to 1994. Gruppo Piemontese Incidentalomi Surrenalici

BACKGROUND

The incidental discovery of an adrenal mass poses the problem of distinguishing between the frequent benign masses and the infrequent malignant ones that require surgery. Univocal guidelines to approach this problem are unavailable.

OBJECTIVE

To perform a survey of the clinical management of incidentally discovered adrenal masses (ie, adrenal incidentalomas).

DESIGN

A multicentric retrospective analysis of hospital medical records of adrenal incidentalomas diagnosed during a 5-year period; the medical records were scrutinized for demographic data and clinical details by means of a specifically tailored questionnaire.

SETTING

The major surgical and medical centers of Piedmont, a northern Italian region with approximately 4 million inhabitants. The recruitment pattern of these centers was unselected.

PATIENTS

The definition of adrenal incidentaloma was limited to patients with a physical examination and a clinical history unindicative of adrenal disease. Exclusion criteria also included hypertension of suspected endocrine origin and a history of neoplasms known to metastasize frequently in the adrenal glands. Two hundred twenty-four medical records were collected, and 210 were analyzed (14 excluded a posteriori).

RESULTS

Most patients were in their 50s and 60s, and women were predominantly affected. The frequency of adrenocortical cancer was 13% among patients operated on. The tumor diameter was highly correlated with the risk of cancer; a cutoff at 5 cm had a sensitivity of 93% with a specificity of 64% in discriminating between benign and malignant cortical lesions.

CONCLUSIONS

The occurrence of adrenocortical carcinoma among adrenal incidentalomas is not rare. The evaluation of the mass size is a simple and effective method for selecting patients at risk for cancer. The indication for surgery of masses larger than 5 cm, or of masses of any diameter that have suspicious imaging characteristics, limits unnecessary operations and costs.

Malonyl-coenzyme A:acyl carrier protein acyltransferase of Streptomyces glaucescens: a possible link between fatty acid and polyketide biosynthesis

Streptomyces glaucescens, a Gram-positive soil bacterium, produces the polyketide antibiotic tetracenomycin (Tcm) C. To study possible biochemical connections between the biosynthesis of bacterial fatty acids and polyketides, the abundant acyl carrier protein (ACP) detected throughout the growth of the tetracenomycin (Tcm) C-producing S. glaucescens was purified to homogeneity and found to behave like many other ACPs from bacteria and plants (apparent M(r) of 20,000 on gel filtration chromatography, apparent M(r) of 3400-4800 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, and pI approximately 3.8). By using an oligodeoxynucleotide synthesized in accordance with the sequence of residues 25-36 of the ACP, the fabC gene encoding this protein was cloned, and expression of this gene in Escherichia coli yielded the ACP entirely as the active holoenzyme. Sequence analysis of 4.3 kilobases (kb) of DNA flanking fabC revealed the presence of three other genes oriented in the same transcriptional direction in the order fabD, fabH, fabC, and fabB. Each of the four genes is predicted to encode proteins with high sequence similarity to the following components of the E. coli fatty acid synthase (FAS): the FabD malonyl-coenzyme A:ACP acyltransferase (MAT), FabH 3-oxoacyl:ACP synthase III, AcpP ACP, and FabB 3-oxoacyl:ACP synthase I. Expression of the S. glaucescens fabD gene in E. coli produced active MAT able to catalyze in vitro the transfer of radioactive malonate from malonyl-coenzyme A to the E. coli AcpP and S. glaucescens FabC ACPs, as well as to the TcmM ACP component of the Tcm type II polyketide synthase [Shen, B., et al. (1992) J. Bacteriol 174, 3818-3821]. Expression of fabD also restored the high-temperature growth of the E. coli fabD89 mutant that bears a temperature-sensitive MAT. The latter finding and the close similarity between the organization of the S. glaucescens fabDHCB and E. coli FAS-encoding genes (fabH/fabD/fabG/acpP/fabF) suggest that the S. glaucescens genes encode FAS enzymes. Moreover, on the basis of its in vitro activity, it is possible that the S. glaucescens FabD MAT is responsible for charging the TcmM ACP with malonate in vivo, a key step in the synthesis of the deca(polyketide) precursor of Tcm C. This implies the existence of a functional connection between fatty acid and polyketide metabolism in this bacterium.

Purification to homogeneity and the N-terminal sequence of human leukotriene C4 synthase: a homodimeric glutathione S-transferase composed of 18-kDa subunits

Human leukotriene C4 (LTC4) synthase was purified > 25,000-fold to homogeneity from the monocytic leukemia cell line THP-1. Beginning with taurocholate-solubilized microsomal membranes, LTC4 synthase was chromatographically resolved by (i) anion exchange, (ii) affinity chromatography (through a resin of biotinylated LTC2 immobilized on streptavidin-agarose), and then (iii) gel filtration. The final preparation contained only an 18-kDa polypeptide. The molecular mass of the pure polypeptide was consistent with an 18-kDa polypeptide from THP-1 cell membranes that was specifically photolabeled by an LTC4 photoaffinity probe, 125I-labeled azido-LTC4. On calibrated gel-filtration columns, purified LTC4 synthase activity eluted at a volume corresponding to 39.2 +/- 3.3 kDa (n = 12). The sequence of the N-terminal 35 amino acids was determined and found to be a unique sequence composed predominantly of hydrophobic amino acids and containing a consensus sequence for protein kinase C phosphorylation. We therefore conclude that human LTC4 synthase is a glutathione S-transferase composed of an 18-kDa polypeptide that is enzymatically active as a homodimer and may be phosphoregulated in vivo.