Penile erection and cardiovascular function: effects and pathophysiology

Penile erection (PE) is a hemodynamic event that results from a neuroendocrine process, and it is influenced by the cardiovascular status of the patient. However, it may also modulate an individual's cardiovascular events. The present study provides the mechanisms involved in the association of PE and cardiovascular function. Erection upsurges the cardiac rate, blood pressure, and oxygen uptake. Sex-enhancing strategies, such as phosphodiesterase inhibitors, alprostadil, and testosterone also promote vasodilatation and cardiac performance, thus preventing myocardial infarction. More so, drugs that are used in the treatment of hypertensive heart diseases (such as angiotensin system inhibitors and β-blockers) facilitate vasodilatation and PE. These associations have been linked with nitric oxide- and testosterone-dependent enhancing effects on the vascular endothelium. In addition, impaired cardiovascular function may negatively impact PE; therefore, impaired PE may be a pointer to cardiovascular pathology. Hence, evaluation of the cardiovascular status of an individual with erectile dysfunction (ED) is essential. Also, employing strategies that are used in maintaining optimal cardiac function may be useful in the management of ED.

Dysregulated expression of miR‑367 in disease development and its prospects as a therapeutic target and diagnostic biomarker (Review)

MicroRNA (miR)-367 has a wide range of functions in gene regulation and as such plays a critical role in cell proliferation, differentiation and development, making it an essential molecule in various physiological processes. miR-367 belongs to the miR-302/367 cluster and is located in the intronic region of human chromosome 4 on the 4q25 locus. Dysregulation of miR-367 is associated with various disease conditions, including cancer, inflammation and cardiac conditions. Moreover, miR-367 has shown promise both as a tumor suppressor and a potential diagnostic biomarker for breast, gastric and prostate cancer. The elucidation of the essential role of miR-367 in inflammation, development and cardiac diseases emphasizes its versatility in regulating various physiological processes beyond cancer biology. However, further research is necessary to fully understand the complex regulatory mechanisms involving miR-367 in different physiological and pathological contexts. In conclusion, the versatility and significance of miR-367 makes it a promising candidate for further study and in the development of new diagnostic and therapeutic strategies.

Pediatric brain abscess with fatal outcome caused by hypervirulent Klebsiella pneumoniae, serotype K2-ST65

Hypervirulent Klebsiella pneumoniae (hvKp) is an emerging pathotype in addition to classical Klebsiella pneumoniae, with its ability to cause life-threatening, community-acquired metastatic infections even in healthy individuals. We presented a case of cerebral abscess preceded by otitis media in a 10-year-old child caused by hvKp. The isolates from blood pus aspirate were later identified as K. pneumoniae capsular serotype K2 and closely related to sequence type (ST65), with multiple hypervirulent genes detected (rmpA, rmpA2, iucA and peg344). She succumbed to death despite surgical drainage and susceptible antibiotic therapy. Clinicians should be cognizant of the rising incidence of hvKp infections in pediatric populations.

Bending effect on the Majorana bound states in planar Josephson junctions

We consider the bending effect on the formation of Majorana bound states (MBSs) in planar Josephson junctions where the normal stripe is tilted in a V shape. Our results show that the MBSs remain robust for moderate bending angles. Beyond some critical angles, the degradation of MBSs can be revealed by its eigenspectrum as well as the Majorana polarization (MP). Our results show that the parameter space of bending angle for robust MBSs can be significantly enlarged by tuning the superconducting phase difference across the Josephson junction. These findings suggest that the interplay of the junction geometry and the device parameters provides richer degree of freedom in designing topological superconducting devices for future applications. The MP analysis is an indispensable tool for characterizing the Majorana states.

Theoretical investigation of the scanning tunneling microscopy of Majorana bound states in topological superconductor vortices

Scanning tunneling microscopy (STM) is an indispensable tool in detecting Majorana bound states (MBSs) in vortices of topological superconductors. By reducing the computational complexity via non-uniform grids, we systematically study the tunnel coupling as well as the temperature dependence of the differential conductance of MBSs in two dimensional devices. Numerical results show that the conductance peak approaches the quantized value 2e ²/h in strong coupling limit at low temperatures which are characteristic features of MBSs. More interestingly, a conductance local minimum in the spatially scanning is observed when the STM tip is placed at the vortex center. The dip structure can be enhanced with increased temperature or enlarged vortex size. We ascribe this observation to the sensitivity of the Andreev reflection processes of carriers at the vortex center where the thermal energy could be comparable to the vanishing pair potential. We also investigate the STM of two-vortex systems where the hybridization of the vortices can lead to oscillatory behavior of the state energy. With small inter-vortex distances, the original MBSs in vortices can merge into topologically trivial states and the conductance peak can be significantly suppressed.

The Significant Association between Polymicrobial Diabetic Foot Infection and Its Severity and Outcomes

Background

Foot infection is a major complication of diabetes mellitus (DM) and its agents are usually polymicrobial. This study aims to describe the agent and determine the association between polymicrobial infections and the severity of diabetic foot infections (DFI) and their outcomes.

Methods

This retrospective cohort study was conducted during one year and it involved 104 patients. Their records were reviewed and assessed. The causative agents and its sensitivity pattern were noted. The results were presented as descriptive statistic and analysed.

Results

A total of 133 microorganisms were isolated with 1.28 microorganisms per lesion. The microorganism isolated were 62% (n = 83) GN (Gram-negative) and 38% (n = 50) GP (Gram-positive). GN microorganisms include Pseudomonas spp (28%), Proteus spp (11%), Klebsiella spp (8%) and E. coli (4%). Staphylococcus aureus (54%) was predominant among GP, followed by Group B Streptococci (26%) and Enterococcus spp (6%). Thirty patients (28.8%) had polymicrobial infections. The association between the quantity of microorganisms and severity of DFI was significant. Among severe DFI cases, 77.8% with polymicrobial microorganisms underwent amputation compared to 33.3% with monomicrobial infection.

Conclusion

GN microorganisms were predominantly isolated from DFIs and remained sensitive to widely used agents. Polymicrobial infections were associated with DFI severity.

Terahertz acoustic phonon detection from a compact surface layer of spherical nanoparticles powder mixture of aluminum, alumina and multi-walled carbon nanotube

We present terahertz spectroscopy study on spherical nanoparticles powder mixture of aluminum, alumina, and MWCNTs induced by surface mechanical attrition treatment (SMAT) of aluminum substrates. Surface alloying of AL, Al₂O₃ 0.95% and MWCNTs 0.05% powder mixture was produced during SMAT process, where a compact surface layer of about 200 μm due to ball bombardment was produced from the mixture. Al₂O₃ alumina powder played a significant role in MWCNTs distribution on surface, those were held in deformation surface cites of micro-cavities due to SMAT process of Al. The benefits are the effects on resulted optical properties of the surface studied at the terahertz frequency range due to electrical isolation confinement effects and electronic resonance disturbances exerted on Al electronic resonance at the same range of frequencies. THz acoustic phonon around 0.53-0.6THz (17-20cm^-1) were observed at ambient conditions for the spherical nanoparticles powder mixture of Al, Al₂O₃ and MWCNTs. These results suggested that the presence of Al₂O₃ and MWCNTs during SMAT process leads to the optically detection of such acoustic phonon in the THz frequency range.

Computational study of the inhibitory mechanism of the kinase CDK5 hyperactivity by peptide p5 and derivation of a pharmacophore

The hyperactivity of the cyclic dependent kinase 5 (CDK5) induced by the activator protein p25 has been linked to a number of pathologies of the brain. The CDK5-p25 complex has thus emerged as a major therapeutic target for Alzheimer's disease (AD) and other neurodegenerative conditions. Experiments have shown that the peptide p5 reduces the CDK5-p25 activity without affecting the endogenous CDK5-p35 activity, whereas the peptide TFP5, obtained from p5, elicits similar inhibition, crosses the blood-brain barrier, and exhibits behavioral rescue of AD mice models with no toxic side effects. The molecular basis of the kinase inhibition is not currently known, and is here investigated by computer simulations. It is shown that p5 binds the kinase at the same CDK5/p25 and CDK5/p35 interfaces, and is thus a non-selective competitor of both activators, in agreement with available experimental data in vitro. Binding of p5 is enthalpically driven with an affinity estimated in the low µM range. A quantitative description of the binding site and pharmacophore is presented, and options are discussed to increase the binding affinity and selectivity in the design of drug-like compounds against AD.

Impact of subdomain D1 of the short form S1b of the human prolactin receptor on its inhibitory action on the function of the long form of the receptor induced by prolactin

BACKGROUND

Long-form (LF) homodimers of the human prolactin receptor (PRLR) mediate prolactin's diverse actions. Short form S1b inhibits the LF function through heterodimerization. Reduced S1b/LF-ratio in breast cancer could contribute to tumor development/progression. Current work defines the structural and functional relevance of the D1 domain of S1b on its inhibitory function on prolactin-induced LF function.

METHODS

Studies were conducted using mutagenesis, promoter/signaling analyses, bioluminescence resonance energy transfer (BRET) and molecular modeling approaches.

RESULTS

Mutation of E69 in D1 S1b or adjacent residues at the receptor surface near to the binding pocket (S) causes loss of its inhibitory effect while mutations away from this region (A) or in the D2 domain display inhibitory action as the wild-type. All S1b mutants preserved prolactin-induced Jak2 activation. BRET reveals an increased affinity in D1 mutated S1b (S) homodimers in transfected cells stably expressing LF. In contrast, affinity in S1b homodimers with either D1 (A) or D2 mutations remained unchanged. This favors LF mediated signaling induced by prolactin. Molecular dynamics simulations show that mutations (S) elicit major conformational changes that propagate downward to the D1/D2 interface and change their relative orientation in the dimers.

CONCLUSIONS

These findings demonstrate the essential role of D1 on the S1b structure and its inhibitory action on prolactin-induced LF-mediated function.

GENERAL SIGNIFICANCE

Major changes in receptor conformation and dimerization affinity are triggered by single mutations in critical regions of D1. Our structure-function/simulation studies provide a basis for modeling and design of small molecules to enhance inhibition of LF activation for potential use in breast cancer treatment.

Hospital-acquired Clostridium difficile infection among patients with type 2 diabetes mellitus in acute medical wards

BACKGROUND

Clostridum difficile (C. difficile) infection is increasingly seen among hospitalised patients with type 2 diabetes mellitus but its rate and associated risk factors are not known. We aimed to determine the rate and characteristics of hospital-acquired C. difficile infection in subjects with type 2 diabetes mellitus admitted into acute medical wards.

METHODS

Our prospective cross-sectional study involved 159 patients with established type 2 diabetes mellitus admitted into acute medical wards who developed a hospital-acquired C. difficile infection. Stools were tested for C. difficile toxins using a toxin A/B kit and a toxin A kit. Clinical features, laboratory findings, types of antibiotics, and use of a proton pump inhibitor were examined for their association with the infection.

RESULTS

Thirteen subjects were positive for toxin A and one for toxin B. Using univariable analysis, we found that patients with type 2 diabetes mellitus and hospital acquired C. difficile infection were younger (mean 53.8 years, p=0.02), had diarrhoea and abdominal pain (p=0.001) but no fever. Sepsis (p=0.02) and use of a proton pump inhibitor (p=0.01) were more commonly implicated as the cause of the infection. Of the various types of antibiotics prescribed, carbapenem (28.6% vs 4.1%, p=0.01) and metronidazole (42.9% vs 19.3%, p=0.04) were significantly associated with hospital acquired C. difficile infection.

CONCLUSIONS

Patients with type 2 diabetes mellitus admitted into acute medical wards and who developed hospital-acquired C. difficile infection have distinct characteristics.

The significance of coagulase-negative staphylococci bacteremia in a low resource setting

Introduction: Coagulase-negative staphylococci (CoNS) are a group of micro-organisms that are increasingly implicated as a cause of significant infection and the leading cause of bloodstream infection (BSI). One important predictor of true BSI is the isolation of CoNS from multiple blood cultures, presuming that the isolates represent the same species. Thus the objective of this study was to determine the significance of repeated CoNS isolated from blood cultures. Methodology: This was a prospective laboratory study which was initiated in June 2007 and lasted until July 2008. CoNS isolates were obtained from patients who had two positive blood cultures within a 14-day interval. CoNS were identified to the species level using an API-Staph, and antibiotics susceptibility testing was performed according to Clinical and Laboratory Standards Institute specifications. Strain relatedness was confirmed using pulsed-field gel electrophoresis. Results: During the study period, 202 CoNS-positive samples were isolated from 101 patients. The most common species isolated was Staphylococcus epidermidis (59.0%), and 83.2% of the patients isolated the same species of CoNS from repeated blood cultures. Among the isolates of the same species, only 40.7% had the same antibiogram. CoNS with the same species and antibiogram had 93.3% probability of belonging to the same strain. Most (65.5%) of the patients were treated with antibiotics, primarily from the glycopeptides group. Conclusion: Speciation and antibiogram of CoNS from repeated blood cultures are adequate in determining the significance of repeated CoNS isolated from blood cultures.

Early detection of prostate cancer: evaluating the diagnostic performance of prostate specific antigen by comparing with histological technique among africans

This study was conducted to investigate the diagnostic performance characteristics of prostate specific antigen (PSA) by comparing serum PSA value with histological findings in patients suspevted of having prostate cancer in Aminu Kano Teaching Hospital. Nigeria. Clinical and Laboratory records were examined and collated for serum PSA values, together with histological findings of biopsy specimen, clinical diagnosis, age of patients, and mode of presentation. The serum PSA values were determined by ELECSYS 1010 autoanalysers Roche, Germany based on electrochemiluminescence immunoassay technique. The results show that serum PSA values increase with age in the assymptomatic non-cancer patients who came for medical check up but were within normal limit. In prostatic disease conditions PSA values were raised in benign prostatic hyperplasia 35.957± 4.0315ng/ml, in undifferentiated carcinoma 56.22±4.295ng/ml and adenocarcinoma >100ng/ml as compared to the normal range (0-4ng/ml). These cases were confirmed by histological diagnosis. It is concluded that PSA evaluations is a sensitive marker for prostate cancer but because of various other conditions that affect serum PSA concentration, other methods of investigations such as Digital Rectal examination, Trans Urethral Ultra-Sonography and histological examination should be combined to confirm diagnosis. Prognosis of patients will be better if early diagnosis is made.

Solid-pseudopapillary carcinoma: a case study and literature review

Solid-pseudopapillary tumour (SPT) is a rare exocrine tumour of the pancreas and is considered to have low malignant potential. Few morphological criteria are used to predict malignant behaviour such as equivocal perineural invasion, angioinvasion and invasion to surrounding tissue, and should be designated as solid-pseudopapillary carcinoma (SPC). We report a case of SPC. Clinical and radiological findings are typical for SPT with no metastatic disease. There is no tumour recurrence after 4 months postresection. Clinical history and radiological findings were retrieved from the patient's record sheet and Viarad system. H&E staining and few immunoproxidase staining were reviewed by several pathologists. The histological findings are typical for SPT, with additional perineural invasion. There is no angioinvasion or capsular invasion identified. This is our first experience in diagnosing and managing SPC. We look forward to seeing the patient's disease status during her next routine follow-up. We expect good disease-free survival and very low risk of tumour recurrence, in view of only one risk factor (perineural invasion) and uninvolved surgical margins by the tumour.

Prevalence of Clostridium difficile toxin in diarhoeal stool samples of patients from a tertiary hospital in North Eastern Penisular Malaysia

This study describes the prevalence of Clostridium difficile toxin (CDT) in loose stool samples from inpatients aged more than two years of a tertiary hospital. A total of 175 samples that had been examined were from stool samples that were sent to the Medical Microbiology & Parasitology Laboratory for various clinical indications. The toxin was detected by a commercial immunochromatograhic test, and the patients' demography, clinical features, treatment and outcomes were analyzed from their medical records. Clostridium difficile toxin was positive in 24 (13.7%) of the stool samples. Male and female were 11 (45.8%) and 13 (54.2%) respectively, with the majority of them aged more than 50 years. Most were from medical wards (n = 21, 87.5%), with the rest from surgical wards (n = 2, 8.3%) and intensive care units (n = 1, 3.4%). All the CDT positive patients had history of prior antibiotic usage within 6 weeks before the detection of the toxin. The mean duration of antibiotics usage was 17.75 (+/- 13.75) days, while the mean duration of diarrhea was 5.21((+/- 5.85) days. Eighteen patients had underlying medical illnesses that were diabetes mellitus, chronic renal disease, hypertension, ischaemic heart disease, cerebrovascular disease and malignancy; with seven of them being CDT positive while on chemotherapy. Stool occult blood test was positive in 15 patients whereas presence of pus cells in the CD positive stool samples were detected in 21 patients. The duration of hospitalization among the patients was 27.96 (+/- 23.22) days.

Microcatheter to recanalization (procedure time) predicts outcomes in endovascular treatment in patients with acute ischemic stroke: when do we stop?

BACKGROUND AND PURPOSE

Endovascular treatment for acute ischemic stroke consists of various mechanical and pharmacologic modalities used for recanalization of arterial occlusions. We performed this study to determine the relationship among procedure time, recanalization, and clinical outcomes in patients with acute ischemic stroke undergoing endovascular treatment.

MATERIALS AND METHODS

We analyzed data from consecutive patients with acute ischemic stroke who underwent endovascular treatment during a 6-year period. Demographic characteristics, NIHSS score before and 24 hours after the procedure, and discharge mRS score were ascertained. Procedure time was defined by the time interval between microcatheter placement and recanalization or completion of the procedure. We estimated the procedure time after which favorable clinical outcome was unlikely, even after adjustment for age, time from symptom onset, and admission NIHSS scores.

RESULTS

We analyzed 209 patients undergoing endovascular treatment (mean age, 65 ± 16 years; 109 [52%] men; mean admission/preprocedural NIHSS score, 15.3 ± 6.8). Complete or partial recanalization was observed in 176 (84.2%) patients, while unfavorable outcome (mRS 3-6) was observed in 138 (66%) patients at discharge. In univariate analysis, patients with procedure time ≤30 minutes had lower rates of unfavorable outcome at discharge compared with patients with procedure time ≥30 minutes (52.3% versus 72.2%, P = .0049). In our analysis, the rates of favorable outcomes in endovascularly treated patients after 60 minutes were lower than rates observed with placebo treatment in the Prourokinase for Acute Ischemic Stroke Trial. In logistic regression analysis, unfavorable outcome was positively associated with age (P = .0012), admission NIHSS strata (P = .0017), and longer procedure times (P = .0379).

CONCLUSIONS

Procedure time in patients with acute ischemic stroke appears to be a critical determinant of outcomes following endovascular treatment. This highlights the need for procedure time guidelines for patients being considered for endovascular treatment in acute ischemic stroke.

Adulticidal Activity of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under Laboratory Conditions

BACKGROUND

There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions.

METHODS

These tests were carried out using WHO recommended bioassay method for adult mosquitoes.

RESULTS

The extracts from black pepper was more effective as adulticide with lowest LC(50) values (2.26% and 8.4%) against Aedes aegypti and Anopheles stephensi after 24 h of exposure while after 48h (1.56% and 5.11%) respectively. In terms of LC(90) value black pepper was best with (8.66% and 30.1%) against Ae. aegypti and An. stephensi after 24 h of exposure while after 48h (4.59% and 17.3%) respectively. In terms of LT(50) black pepper took 15 h to kill 50% tested population of Ae. aegypti while against An. stephensi it took more than 2 days. In terms of percentage mortality black pepper kill 84% of the population of Ae. aegypti and 44.75% of the An. stephensi population.

CONCLUSION

Black pepper showed best results in term of LC(50), LC(90), LT(50) and percentage mortality against Ae. aegypti and An. stephensi. Our study suggested that the plant extracts have potential to kill adult mosquitoes, are environment friendly and can be used for the control of mosquitoes.

The clinical and cost effectiveness of bee honey dressing in the treatment of diabetic foot ulcers

Honey is known, since antiquity, as an effective wound dressing. Emergence of resistant strains and the financial burden of modern dressings, have revived honey as cost-effective dressing particularly in developing countries. Its suitability for all stages of wound healing suggests its clinical effectiveness in diabetic foot wound infections. Thirty infected diabetic foot wounds were randomly selected from patients presenting to Surgery Department, Suez Canal University Hospital, Ismailia, Egypt. Honey dressing was applied to wounds for 3 months till healing, grafting or failure of treatment. Changes in grade and stage of wounds, using University of Texas Diabetic Wound Classification, as well as surface area were recorded weekly. Bacterial load was determined before and after honey dressing. Complete healing was significantly achieved in 43.3% of ulcers. Decrease in size and healthy granulation was significantly observed in another 43.3% of patients. Bacterial load of all ulcers was significantly reduced after the first week of honey dressing. Failure of treatment was observed in 6.7% of ulcers. This study proves that commercial clover honey is a clinical and cost-effective dressing for diabetic wound in developing countries. It is omnipresence and concordance with cultural beliefs makes it a typical environmentally based method for treating these conditions.

Structural and dynamic determinants of ligand binding and regulation of cyclin-dependent kinase 5 by pathological activator p25 and inhibitory peptide CIP

The crystal structure of the cdk5/p25 complex has provided information on possible molecular mechanisms of the ligand binding, specificity, and regulation of the kinase. Comparative molecular dynamics simulations are reported here for physiological conditions. This study provides new insight on the mechanisms that modulate such processes, which may be exploited to control pathological activation by p25. The structural changes observed in the kinase are stabilized by a network of interactions involving highly conserved residues within the cyclin-dependent kinase (cdk) family. Collective motions of the proteins (cdk5, p25, and CIP) and their complexes are identified by principal component analysis, revealing two conformational states of the activation loop upon p25 complexation, which are absent in the uncomplexed kinase and not apparent from the crystal. Simulations of the uncomplexed inhibitor CIP show structural rearrangements and increased flexibility of the interfacial loop containing the critical residue E240, which becomes fully hydrated and available for interactions with one of several positively charged residues in the kinase. These changes provide a rationale for the observed high affinity and enhanced inhibitory action of CIP when compared to either p25 or the physiological activators of cdk5.

The antibacterial properties of Malaysian tualang honey against wound and enteric microorganisms in comparison to manuka honey

Background

Antibiotic resistance of bacteria is on the rise, thus the discovery of alternative therapeutic agents is urgently needed. Honey possesses therapeutic potential, including wound healing properties and antimicrobial activity. Although the antimicrobial activity of honey has been effectively established against an extensive spectrum of microorganisms, it differs depending on the type of honey. To date, no extensive studies of the antibacterial properties of tualang (Koompassia excelsa) honey on wound and enteric microorganisms have been conducted. The objectives of this study were to conduct such studies and to compare the antibacterial activity of tualang honey with that of manuka honey.

Methods

Using a broth dilution method, the antibacterial activity of tualang honey against 13 wound and enteric microorganisms was determined; manuka honey was used as the control. Different concentrations of honey [6.25-25% (w/v)] were tested against each type of microorganism. Briefly, two-fold dilutions of honey solutions were tested to determine the minimum inhibitory concentration (MIC) against each type of microorganism, followed by more assays within a narrower dilution range to obtain more precise MIC values. MICs were determined by both visual inspection and spectrophotometric assay at 620 nm. Minimum bactericidal concentration (MBC) also was determined by culturing on blood agar plates.

Results

By visual inspection, the MICs of tualang honey ranged from 8.75% to 25% compared to manuka honey (8.75-20%). Spectrophotometric readings of at least 95% inhibition yielded MIC values ranging between 10% and 25% for both types of honey. The lowest MBC for tualang honey was 20%, whereas that for manuka honey was 11.25% for the microorganisms tested. The lowest MIC value (8.75%) for both types of honey was against Stenotrophomonas maltophilia. Tualang honey had a lower MIC (11.25%) against Acinetobacter baumannii compared to manuka honey (12.5%).

Conclusion

Tualang honey exhibited variable activities against different microorganisms, but they were within the same range as those for manuka honey. This result suggests that tualang honey could potentially be used as an alternative therapeutic agent against certain microorganisms, particularly A. baumannii and S. maltophilia.

The Relative Performance Capabilities of Passive, Active and Semi-Active Car Suspension Systems

Based on the well-known quarter car representation of the automobile suspension design problem, pdomnce parameters relating to passenger discomfort, working space and tyre load variability are generated for passive, active and semi-active suspension systems. Active systems of two types having different hardware implications are considered, and linear optimal control theory is used in each case to derive a good set o control law parameters. The semi-active systems studied have control laws based on the fully active systems, but are capable only of dissipating energy, so that where the corresponding active system would be acting as an energy supply, the semi-active system switches off Practically realizable switching dynamics are assumed in the calculations. Results for all the systems, for one road surface roughness and vehicle speed, are generated in a form which allows comparison between systems of diffient types which have equal suspension working space requirements. The wider implications of the results are discussed, and far-reaching conclusions about the relative capabilities and design features of passive, active and semi-active systems are drawn.

Key issues in the computational simulation of GPCR function: representation of loop domains

Some key concerns raised by molecular modeling and computational simulation of functional mechanisms for membrane proteins are discussed and illustrated for members of the family of G protein coupled receptors (GPCRs). Of particular importance are issues related to the modeling and computational treatment of loop regions. These are demonstrated here with results from different levels of computational simulations applied to the structures of rhodopsin and a model of the 5-HT2A serotonin receptor, 5-HT2AR. First, comparative Molecular Dynamics (MD) simulations are reported for rhodopsin in vacuum and embedded in an explicit representation of the membrane and water environment. It is shown that in spite of a partial accounting of solvent screening effects by neutralization of charged side chains, vacuum MD simulations can lead to severe distortions of the loop structures. The primary source of the distortion appears to be formation of artifactual H-bonds, as has been repeatedly observed in vacuum simulations. To address such shortcomings, a recently proposed approach that has been developed for calculating the structure of segments that connect elements of secondary structure with known coordinates, is applied to 5-HT2AR to obtain an initial representation of the loops connecting the transmembrane (TM) helices. The approach consists of a simulated annealing combined with biased scaled collective variables Monte Carlo technique, and is applied to loops connecting the TM segments on both the extra-cellular and the cytoplasmic sides of the receptor. Although this initial calculation treats the loops as independent structural entities, the final structure exhibits a number of interloop interactions that may have functional significance. Finally, it is shown here that in the case where a given loop from two different GPCRs (here rhodopsin and 5-HT2AR) has approximately the same length and some degree of sequence identity, the fold adopted by the loops can be similar. Thus, in such special cases homology modeling might be used to obtain initial structures of these loops. Notably, however, all other loops in these two receptors appear to be very different in sequence and structure, so that their conformations can be found reliably only by ab initio, energy based methods and not by homology modeling.

Impact of industrial wastewater disposal on surface water bodies in Mostord area, north greater Cairo

The studied area (Shoubra El-Khima, Bahteem and Mostorod) lies in the industrial area north of Greater Cairo. The area suffers from several environmental problems such as sewage and disposal of pollutants from the surrounding factories into the surface water pathways in the area. Water samples were collected seasonally from different waterways found in the area, domestic and or industrial liquid wastes from 12 discharge tubes of different factories (as a point source of pollution). Chemical characteristics of different water samples and its heavy metals content were determined using ion coupled plasma technique (ICP). Results indicate that industrial and domestic wastewater samples contain several toxic levels of tested heavy metals (Cd, Co, Pb and Ni) which have a serious impact on surface waterways in the area. Shebin El-Qanater collector drain samples exhibited the highest levels of Cd, Co, Pb and Ni compared to other tested water bodies. Mostorod collector drain samples showed the highest levels of Zn and Cu. Industrial effluent samples collected from Cairo Company for Fabric industry had the highest amounts of total Zn Cu, Cd, Co and Pb, while Delta steel company discharges the highest amounts of total Fe and Mn. Al-Ahleya Plastic Company discharges the highest amounts of total-Ni. Generally, it is necessary to impose the environmental laws and its regulation regarding the industrial wastewater treatments and disposals to minimize the risk of the adverse effects of these pollutants.

Differences in conformational properties of the second intracellular loop (IL2) in 5HT(2C) receptors modified by RNA editing can account for G protein coupling efficiency

Adenosine-to-inosine RNA editing events that have been demonstrated for 5HT (2C) receptors resulted in alterations of the amino acid sequence at positions 156, 158 and 160 in the intracellular loop 2 (IL2) region. The edited receptor isoforms were shown to have reduced basal activity, but similar maximum responses to agonist binding. To identify the molecular mechanism of these pharmacological effects of editing we explored the conformational properties of the edited IL2 in comparison with the wild type. The results from conformational studies of the IL2 isoforms, using biased Monte Carlo simulations with an implicit solvent model based on a screened Coulomb potential, show that the compared loops differ in their preferred spatial orientations as a result of differences in the conformational space that is accessible to them by energy criteria. For the IL2 of the unedited (5HT (2C-INI) ) receptor, the preference for structures oriented towards the 7TM bundle is larger than for the 5HT (2C-VGV) edited receptor. This difference in preferred orientation can affect the association of IL2 with other intracellular loop domains involved in G protein coupling and hence the coupling efficiency. The results illustrate the high sensitivity of the system to small changes in the interaction surface presented to other intracellular loops, and/or the G protein.

Outcomes of noncardiac surgery after coronary bypass surgery or coronary angioplasty in the Bypass Angioplasty Revascularization Investigation (BARI)

PURPOSE

Previous studies have shown that coronary artery bypass surgery reduces the risk of cardiac complications after noncardiac surgery. Whether coronary angioplasty provides equivalent protection is not known.

SUBJECTS AND METHODS

Patients were randomly assigned to undergo cardiac artery bypass surgery or angioplasty as part of the Bypass Angioplasty Revascularization Investigation trial. All subsequent noncardiac surgeries during a mean (+/- SD) follow-up of 7.7 years were recorded among participants in the ancillary Study of Economics and Quality of Life. Rates of mortality and nonfatal myocardial infarction, length of stay, and hospital costs were compared by the original randomized assignment.

RESULTS

A total of 501 patients had noncardiac surgery at a median of 29 months after their most recent coronary revascularization procedure. Mortality and nonfatal myocardial infarction within 30 days of the first noncardiac surgery occurred in 4 of the 250 of the surgery-assigned patients and in 4 of the 251 of the angioplasty-assigned patients (P = 1.0). There were no significant differences in the mean length of hospital stay (6.3 +/- 6.7 versus 6.2 +/- 6.8 days; P = 0.47) or hospital cost ($8,920 +/- $11,511 versus $7,785 +/- $7,643; P = 0.33) between the surgery and angioplasty groups. Similar results were obtained when subsequent noncardiac procedures were included in the analysis.

CONCLUSION

Rates of myocardial infarction and death after noncardiac surgery are similarly low after contemporary bypass surgery or angioplasty in patients with multivessel coronary artery disease.

Optical properties of nonequilibrium low-dimensional systems

The optical properties of low-dimensional carrier systems ("quantum wire" type) driven away from equilibrium are studied. The frequency and wave-vector-dependent dielectric function of a quasi-one-dimensional electron system under the action of an exciting external pumping source is derived. The optical responses of the system are obtained in terms of its nonequilibrium thermodynamic state, the latter characterized resorting to a nonequilibrium statistical ensemble formalism.

Quality of life in HIV disease as measured by the McGill quality of life questionnaire

OBJECTIVE

To test the acceptability, validity, and internal consistency reliability of the McGill quality of life questionnaire (MQOL) for persons living with HIV/AIDS.

DESIGN

The validity of MQOL was tested by having HIV-seropositive outpatients complete the 16-item MQOL, a single-item scale (SIS) measuring overall quality of life (QOL), and a physical symptom questionnaire.

METHODS

Factor analysis was used as a guide for construction of MQOL subscales. Validity was studied by determining the correlation between MQOL and SIS, and between MQOL physical measures, CD4 counts and the physical symptoms questionnaire. Multiple regression was employed to determine how best to combine MQOL subscales to predict SIS.

RESULTS

MQOL was acceptable to this patient population. Factor analysis suggests that MQOL can be represented by live measures: a single item measuring physical well-being and four subscales representing physical symptoms, psychological symptoms, existential well-being, and support. Multiple regression analyses suggest that the existential domain contributes greatly to QOL for people with advanced HIV disease (CD4 counts < 100 x 10(6)/l).

CONCLUSION

MQOL is an acceptable and valid measure of QOL for people living with HIV/AIDS, with meaningful and reliable subscales as well as a summary score. The inclusion of a measure of existential well-being in MQOL may make it a more valid measure of QOL, especially for people with advanced disease, than QOL instruments which do not include this domain.

SA gene expression in the proximal tubule of normotensive and hypertensive rats

Previous studies have shown that the SA gene is expressed at higher levels in the kidney of genetically hypertensive rats than in control strains and that in hybrid crosses of genetically hypertensive rats and normotensive controls, markers in or close to the SA gene cosegregate with blood pressure. The present studies examine the localization of the SA gene product in the kidney by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). cDNA was prepared from microdissected nephron segments from Sprague-Dawley (SD) rats, spontaneously hypertensive rats (SHRs), and Wistar-Kyoto (WKY) rats, and RT-PCR was performed using specific primers. In all three strains, SA gene mRNA was found to be abundantly expressed in proximal tubules. SA PCR product was occasionally detected at approximately 100-fold lower abundance in glomeruli, while no signal was obtained from the collecting duct, thick ascending limb of the loop of Henle, or arcuate artery. Within the proximal tubule of normotensive rats, distribution of SA mRNA was found to be strain dependent: in SD rats it was expressed at high levels in the proximal convoluted tubule, whereas in WKY rats it was restricted to the proximal straight tubule. In SHRs, SA PCR product was detected along the entire proximal tubule. Induction of hypertension by renal artery clamping (two-kidney, one-clamp Goldblatt model) did not alter the pattern of expression observed in the SD rat. These results indicate that an extension of SA gene expression to the full length of the proximal tubule accompanies spontaneous hypertension and that in nonhypertensive animals the pattern of gene product expression is more restricted but shows substantial strain variability.

Factors that influence women's nutrition knowledge in Saudi Arabia

We studied knowledge of nutritional needs during pregnancy and lactation in 150 pregnant Saudi women at three primary health care centers in Riyadh, Saudi Arabia. We used an interview schedule to collect data regarding the women's knowledge and to determine the effects of certain independent variables on the knowledge scores. Green et al.'s (1980) PRECEDE model provided the theoretical framework for the study. Descriptive statistics, t test, and chi-square methods were used to analyze the data. The majority of the women had poor nutrition knowledge scores, with no significant differences among the three centers. A positive relationship was found between knowledge score and educational level. Negative relationships were found between knowledge score and number of pregnancies, number of deliveries, and number of living children. The findings have several implications for efforts to improve the health status of women in Saudi Arabia.

Serum strontium estimation as a diagnostic criterion of the type of drowning water

The estimation of serum strontium in rabbits before and after death by drowning, in soft or hard water, or by barbiturate intoxication is highly promising as a method in medicolegal practice. It not only diagnoses drowning but also indicates the type of drowning water. Atomic absorption spectrophotometry is a good method for the estimation.

Effects of reovirus type 1 on the developing mouse embryo

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