Prolonged Mechanical Circumferential Stretch Induces Metabolic Changes in Rat Inferior Vena Cava.

OBJECTIVE/BACKGROUND: Circumferential stretch on the vein wall has been suggested as a potential etiological factor in the development of varicose veins. However, the influence of vein wall stretch on vein metabolism has not yet been explored. The aim of this study was to investigate the effect of short and prolonged mechanical stretch on vein wall metabolism. METHODS: Circular segments of inferior vena cava from male Sprague-Dawley rats were exposed to normal 0.5-g (nonstretched) or high 2-g (stretched) tension for short (4 h) or prolonged (18 h) duration (five vein segments per group). Contraction response to phenylephrine (10-5 M) and KCl (96 mM) was elicited to observe the effect of circumferential stretch on vein function. The polar and organic metabolites in vein tissue were extracted using a bilayer extraction method. Aqueous and organic extracts were analyzed using nuclear magnetic resonance spectroscopy and ultra performance liquid chromatography coupled to mass spectrometry, respectively. Data acquired from both analytical platforms were analyzed using mathematical modeling. RESULTS: Increased concentrations of valine (p = .02) and choline (p = .03) metabolites and triglyceride moieties (p = .03) were observed in veins stretched for 18 h compared with the nonstretched/18 h group. DISCUSSION: Increased concentrations of branched chain amino acid valine and cell membrane constituent choline indicate increased muscle breakdown and increased metabolism of membrane phospholipids under stretch in an ex-vivo model. Increased intensities of triglyceride moieties in stretched vein segments for 18 h suggest that high pressure may induce an inflammatory response. CONCLUSION: This study has shown that prolonged mechanical circumferential stretch (18 h) alters the metabolic profile of rat inferior vena cava.

Physical, Psychological and Social Impact of COVID-19 Pandemic on Healthcare Workers at a COVID Designated Bangladeshi Public Hospital.

The world has been devastated facing the outbreak of a novel infectious disease known as Corona virus disease (COVID-19). This has been declared as a pandemic by the World Health Organization. The frontline health care workers, who are directly involved in the diagnosis, treatment and care of patients with COVID-19, are taking significant personal risks on their own health and those of their family members. Objectives of the study include establishing the physical, psychological and social impact experience by the healthcare workers serving in public hospitals of Bangladesh. This prospective cross-sectional observational study was carried out at Kuwait Bangladesh Friendship Government Hospital, the first Covid-19 designated hospital of Bangladesh between the 1st June and the 31st August, 2020. A total of 294 doctors, nurses, ward boys and ailed healthcare workers were included in this study via purposive sampling. The study found statistically significant (p value 0.024) difference of medical co-morbidities between Covid-19 positive and Covid-19 negative groups of health care professionals. Significant association was found between duration of work and presence during aerosol generating procedure with COVID infectivity of the study subjects. 72.8% respondents experienced public fear of contracting the virus from them and 69.0% noticed negative attitude of the society towards them. Eighty five percent (85.0%) did not get any community support during this pandemic crisis. The health care professionals engaged in COVID-19 treatment have been taking significant personal risk on their life in terms of physical, psychological and social perspective. Providing safeguard to the health care workers are integral components of public health measures for addressing the COVID-19 pandemic. Special interventions to promote their physical wellbeing and arrangement of adequate psychological training need to be immediately implemented to cope up this critical situation.

Knowledge, Attitude and Practice of Undergraduate Medical Students of Bangladesh Regarding COVID-19 and its Vaccination.

Medical students are one of the socially active, reliable, and persuading population of information, prevention and control, and incentive of vaccination to stop the current pandemic situation. Consequently, knowing the status of medical students' knowledge, about symptoms, and transmission of disease, prevention of COVID-19 and their attitudes towards a vaccine is important. This multi-center cross-sectional descriptive study was one of the first ones in Bangladesh among the undergraduate medical students who completed pathology, microbiology, and pharmacology. The study was conducted from March to April 2021, using a convenience sampling method in twelve government and non-government medical colleges. Among 1132 who completed the questionnaire, and 15 students from different centers were excluded from the pre-testing and face validation. The age of the 1117 respondents were 22 to 23 years, of which the majority of the respondents were female 749 (67.0%), and 368 (33.0%) were male. Almost all participants had correct knowledge (84.1%) about the symptoms of COVID-19. But 59.2% had wrong knowledge about transmission of disease by an afebrile person. Above 60.0 % of the participants have worn a facial mask when contacting people, refrained from shaking hands, washed hands, avoided people with signs and symptoms suggestive of COVID-19, and avoided crowded places as a practice of prevention. 37.6% of medical students showed positive attitudes about the participation of management of a COVID-19 patient. Most of the participants' decided to have a vaccine depending on its availability. But 31.5% had trust in natural immunity rather than vaccination. Most undergraduate Medical college students understood the basic information, possessed a positive attitude, and presented good practice towards the COVID-19 and vaccination. They play a crucial role in motivation and acceptance of vaccines among the general citizen to fight back against the pandemic in the country with limited resources.

The effect of pressure-induced mechanical stretch on vascular wall differential gene expression.

High blood pressure is responsible for the modulation of blood vessel morphology and function. Arterial hypertension is considered to play a significant role in atherosclerotic ischaemic heart disease, stroke and hypertensive nephropathy, whereas high venous pressure causes varicose vein formation and chronic venous insufficiency and contributes to vein bypass graft failure. Hypertension exerts differing injurious forces on the vessel wall, namely shear stress and circumferential stretch. Morphological and molecular changes in blood vessels ascribed to elevated pressure consist of endothelial damage, neointima formation, activation of inflammatory cascades, hypertrophy, migration and phenotypic changes in vascular smooth muscle cells, as well as extracellular matrix imbalances. Differential expression of genes encoding relevant factors including vascular endothelial growth factor, endothelin-1, interleukin-6, vascular cell adhesion molecule, intercellular adhesion molecule, matrix metalloproteinase-2 and -9 and plasminogen activator inhibitor-1 has been explored using ex vivo cellular or organ stretch models and in vivo experimental animal models. Identification of pertinent genes may unravel new therapeutic strategies to counter the effects of pressure-induced stretch on the vessel wall and hence minimise its notable complications.

In-vitro identification of distinctive metabolic signatures of intact varicose vein tissue via magic angle spinning nuclear magnetic resonance spectroscopy.

OBJECTIVES: Nuclear magnetic resonance (NMR) spectroscopy is an established tool for metabolic profiling of tissues or biofluids with utility in identifying disease biomarkers and changes in enzymatic or gene expression. This pilot study aims to compare the metabolic profiles of intact varicose and non-varicose vein tissue via magic angle spinning (MAS) NMR spectroscopy with a view to promoting the understanding of the pathogenesis of varicose vein formation. METHODS: Varicose vein tissue (n = 8) was collected from patients undergoing varicose veins surgery. Control non-varicose great saphenous vein samples were collected from patients undergoing lower limb amputation (n = 3) and peripheral arterial bypass surgery (n = 5). Intact tissue samples (average weight 10.33 ± 0.8 mg) from each vein segment were analysed using 1D MAS (1)H NMR (600 MHz) spectroscopy. For selected vein samples, two-dimensional (2D) NMR experiments were performed. Differences between spectra from varicose and non-varicose tissues were elucidated using a variety of multivariate statistical analyses. RESULTS: The metabolic profiles of varicose veins samples were clearly differentiated from non-varicose veins samples. Lipid metabolites were present at a higher concentration in the non-varicose veins group whilst creatine, lactate and myo-inositol metabolites were more characteristic of the varicose veins group. CONCLUSION: We demonstrate differential metabolic profiles between varicose veins and non-varicose veins. Elucidating the metabolic signature underlying varicose veins can further improve our understanding of the biological mechanisms of disease initiation, progression, and aid in identifying putative therapeutic targets.

Effectiveness of fascial closure technique following percutaneous endovascular aneurysm repair.

INTRODUCTION: Percutaneous access and closure is commonly performed for patients undergoing endovascular aneurysm repair (EVAR). It has proven to be a safe and successful method of closure associated with fewer complications when compared with the traditional open technique. Fascial closure is an alternative technique that can be used for closure reducing the risks associated with the open technique. The aim of this study was to assess the safety and durability of fascial closure for failed percutaneous closure device following EVAR. MATERIALS AND METHODS: Over a 12-month period, 49 patients who had undergone EVAR were identified via our EVAR register. Retrospective analysis of the clinical records was undertaken. We identified all the patients who had fascial closure of the groins following a failed percutaneous closure device. Patients had a computed tomography angiogram one month postoperatively, with duplex imaging and clinic follow-up three months later. RESULTS: Fascial closure was performed in 14 groins. It failed in three groins and these patients had traditional open repair. Fascial closure was successful in 11 groins (7 patients). Of these seven patients, one was female (6%). The mean age was 80 years (range 68-92 years). Two patients died and one was lost to follow-up. One pseudoaneurysms were seen on computed tomography angiogram, which was managed conservatively and had resolved on follow-up imaging. CONCLUSIONS: Fascial closure is a very good alternative to open repair after failure of the closure device.

Glucose oxidase immobilization on a novel cellulose acetate-polymethylmethacrylate membrane.

Glucose oxidase (GOD) was immobilized on cellulose acetate-polymethylmethacrylate (CA-PMMA) membrane. The immobilized GOD showed better performance as compared to the free enzyme in terms of thermal stability retaining 46% of the original activity at 70 degrees C where the original activity corresponded to that obtained at 20 degrees C. FT-IR and SEM were employed to study the membrane morphology and structure after treatment at 70 degrees C. The pH profile of the immobilized and the free enzyme was found to be similar. A 2.4-fold increase in Km value was observed after immobilization whereas Vmax value was lower for the immobilized GOD. Immobilized glucose oxidase showed improved operational stability by maintaining 33% of the initial activity after 35 cycles of repeated use and was found to retain 94% of activity after 1 month storage period. Improved resistance against urea denaturation was achieved and the immobilized glucose oxidase retained 50% of the activity without urea in the presence of 5M urea whereas free enzyme retained only 8% activity.

Electrochemical approach of anticancer drugs--DNA interaction.

The interaction of drugs with DNA is among the most important aspects of biological studies in drug discovery and pharmaceutical development processes. In recent years there has been a growing interest in the electrochemical investigation of interaction between anticancer drugs and DNA. Observing the pre and post electrochemical signals of DNA or drug interaction provides good evidence for the interaction mechanism to be elucidated. Also this interaction could be used for the quantification of these drugs and for the determination of new drugs targeting DNA. Electrochemical approach can provide new insight into rational drug design and would lead to further understanding of the interaction mechanism between anticancer drugs and DNA.

Fatal human eosinophilic meningo-encephalitis caused by CNS co-infection with Halicephalobus gingivalis and West Nile virus.

The saprophytic nematode Halicephalobus is a rare cause of fatal human meningo-encephalitis, and West Nile virus is neurotropic flavivirus implicated in a variety of clinical neurologic syndromes. Here we report a case of rapidly progressive CNS encephalopathy and death. Serologic, immuno-histochemical, histopathologic and nucleic acid studies demonstrate the presence of active Halicephalobus and West Nile virus in the CNS tissue. This is the first reported case of co-infection with these neurotropic pathogens.

Enhanced acetylcholine induced relaxation in small mesenteric arteries from pregnant rats: an important role for endothelium-derived hyperpolarizing factor (EDHF).

1. Small mesenteric arteries from pregnant rats demonstrated greater sensitivity (pEC50 : P<0.001) and maximum relaxation (P<0.01) to acetylcholine (ACh) than those of control non-pregnant animals. 2. Maximum relaxation, but not sensitivity, to ACh remained greater (P<0.01) in pregnant animals when evaluated in 25 mM KCl, which prevents relaxation dependent upon hyperpolarization. ACh induced relaxation in the presence of 25 mM KCl was completely inhibited in pregnant and non-pregnant groups by N(omega)-nitro L-arginine methyl ester (L-NAME, 100 microM), indomethacin (INDO, 10 microM) and oxadiazole quinoxalin (ODQ, 1 microM), suggesting pregnancy associated enhancement of dilator prostanoid and/or nitric oxide (NO) synthesis. 3. ACh induced relaxation in 5 mM KCI was only partially inhibited by a combination of N(omega)-nitro L-arginine methyl ester (L-NAME, 100 microM), indomethacin (INDO, 10 microM) and oxadiazole quinoxalin (ODQ, 1 microM). The residual relaxation, which was greater in arteries from pregnant rats (maximum relaxation: P<0.01), was prevented by 25 mM KCl, indicating pregnancy associated enhanced synthesis/ reduced degradation of a hyperpolarizing factor. Residual relaxation to ACh in 5 mM KCl was inhibited by the cytochrome P450 inhibitor, proadifen (1 microM) in the pregnant group (P<0.001). 4. Relaxation to spermine NONOate was similar in pregnant and non-pregnant groups and totally inhibited by ODQ (in the presence of L-NAME). 5. This study suggests that, in addition to enhanced endothelium dependent NO/dilator prostanoid synthesis, a hyperpolarizing factor may contribute to the vascular adaptation to pregnancy.

Intestinal protozoa in wild boars (Sus scrofa) in western Iran.

A total of 12 gastrointestinal tracts of wild boars (Sus scrofa) from western Iran (Luristan) were examined for protozoan infection between September 2000 and November 2001. Of 12 boars examined, 67% harbored one or more species of the following protozoa: Balantidium coli (25%), Tritrichomonas suis (25%), Blastocystis sp. (25%), Entamoeba polecki (17%), Entamoeba suis (8%), Iodamoeba butschlii (17%), and Chilomastix mesnili (8%). Four of these protozoan species also are reported in humans, and persons living in rural areas where wild boars are abundant should take precaution to avoid infection.

Vasoconstrictor and vasodilator responses to tryptamine of rat-isolated perfused mesentery: comparison with tyramine and ß-phenylethylamine.

BACKGROUND AND PURPOSE: Tryptamine increases blood pressure by vasoconstriction, but little is known about its actions on the mesentery, in particular the resistance arteries. Tryptamine interacts with trace amine-associated receptors (TAARs) and because of its structural similarity to 5-HT, it may also interact with 5-HT receptors. Our hypothesis is therefore that the rat mesenteric arterial bed will exhibit vasopressor and vasodepressor responses to tryptamine via both 5-HT and TAARs. EXPERIMENTAL APPROACH: Tryptamine-evoked responses were assayed from pressure changes of the rat-isolated mesenteric vasculature perfused at constant flow rate in the absence and presence of adrenoceptor and 5-HT receptor antagonists. KEY RESULTS: Tryptamine caused dose-dependent vasoconstriction of the mesenteric arterial bed as increases in perfusion pressure. These were unaffected by the α(1) -adrenoceptor antagonist, prazosin, but were attenuated by the non-selective α-adrenoceptor antagonist, phentolamine. The 5-HT(2A) receptor antagonists, ketanserin and ritanserin, abolished the tryptamine-induced pressure increases to reveal vasodilator responses in mesenteric beds preconstricted with phenylephrine. These tryptamine-induced vasodilator responses were unaffected by the 5-HT(7) receptor antagonist, SB269970, but were eliminated by the NOS inhibitor, N(ω) -nitro-L-arginine methyl ester (L-NAME). Tyramine and ß-phenylethylamine also caused vasodilatation in pre-constricted vasculature, which was also abolished by L-NAME. CONCLUSIONS AND IMPLICATIONS: Tryptamine causes vasoconstriction of the mesenteric vasculature via 5-HT(2A) receptors, which when inhibited exposed vasorelaxant effects in pre-constricted tissues. The vasodilatation was independent of 5-HT(2A) and 5-HT(7) receptors but like that for tyramine and ß-phenylethylamine was due to NO release. Potency orders suggest TAAR involvement in the vasodilatation by these trace amines.

Complications of radiofrequency ablation of varicose veins.

Radiofrequency ablation (RFA) has become a valued weapon in the phlebologist's armoury. It offers ease of use and reproducibility with good outcomes. However, as with all interventions, complications arise. In this review we examine the complications inherent with RFA and their relative risk, with their avoidance measures if available. Overall, we find that RFA offers a very safe procedure with rare severe complications.

Gallstone ileus: a difficult emergency diagnosis!

Gallstone ileus (GSI) is a rare cause of mechanical small bowel obstruction. It occurs when a fistula between the gallbladder and the small bowel facilitates the migration of gallstone(s) into the small bowel. The commonest site of impaction is in the terminal ileum. We report the case of a 71-year-old female presenting with GSI diagnosed on CT scan. She was surgically explored and gallstones extracted by a simple enterotomy leading to full recovery of the patient.