Retinal microvascular complexity as a putative biomarker of biological age: a pilot study

Physiological changes associated with aging increase the risk for the development of age-related diseases. This increase is non-specific to the type of age-related disease, although each disease develops through a unique pathophysiologic mechanism. People who age at a faster rate develop age-related diseases earlier in their life. They have an older "biological age" compared to their "chronological age". Early detection of individuals with accelerated aging would allow timely intervention to postpone the onset of age-related diseases. This would increase their life expectancy and their length of good quality life. The goal of this study was to investigate whether retinal microvascular complexity could be used as a biomarker of biological age. Retinal images of 68 participants ages ranging from 19 to 82 years were collected in an observational cross-sectional study. Twenty of the old participants had age-related diseases such as hypertension, type 2 diabetes, and/or Alzheimer's dementia. The rest of the participants were healthy. Retinal images were captured by a hand-held, non-mydriatic fundus camera and quantification of the microvascular complexity was performed by using Sholl's, box-counting fractal, and lacunarity analysis. In the healthy subjects, increasing chronological age was associated with lower retinal microvascular complexity measured by Sholl's analysis. Decreased box-counting fractal dimension was present in old patients, and this decrease was 2.1 times faster in participants who had age-related diseases (p = 0.047). Retinal microvascular complexity could be a promising new biomarker of biological age. The data from this study is the first of this kind collected in Montenegro. It is freely available for use.

The role of miRNA in colorectal cancer diagnosis: A pilot study

Despite recent advances in diagnosis and treatment, colorectal cancer (CRC) remains the third most common cancer worldwide, and has both a poor prognosis and a high recurrence rate, thus indicating the need for new, sensitive and specific biomarkers. MicroRNAs (miRNAs/miRs) are important regulators of gene expression, which are involved in numerous biological processes implicated in tumorigenesis. The objective of the present study was to investigate the expression of miRNAs in plasma and tissue samples from patients with CRC, and to examine their potential as CRC biomarkers. Using reverse transcription-quantitative PCR, it was revealed that miR-29a, miR-101, miR-125b, miR-146a and miR-155 were dysregulated in the formalin-fixed paraffin-embedded tissues of patients with CRC, compared with the surrounding healthy tissue, and these miRNAs were associated with several pathological features of the tumor. Bioinformatics analysis of overlapping target genes identified AGE-RAGE signaling as a putative joint regulatory pathway. miR-146a was also upregulated in the plasma of patients with CRC, compared with the healthy control group, and had a fair discriminatory power (area under the curve, 0.7006), with 66.7% sensitivity and 77.8% specificity. To the best of our knowledge, this distinct five-miRNA deregulation pattern in tumor tissue, and upregulation of plasma miR-146a, were shown for the first time in patients with CRC; however, studies on larger patient cohorts are warranted to confirm their potential to be used as CRC diagnostic biomarkers.

TREND database: Retinal images of healthy young subjects visualized by a portable digital non-mydriatic fundus camera

Topological characterization of the Retinal microvascular nEtwork visualized by portable fuNDus camera (TREND) is a database comprising of 72 color digital retinal images collected from the students of the Faculty of Medicine at the University of Montenegro, in the period from February 18th to March 11th 2020. The database also includes binarized images of manually segmented microvascular networks associated with each raw image. The participant demographic characteristics, health status, and social habits information such as age, sex, body mass index, smoking history, alcohol use, as well as previous medical history was collected. As proof of the concept, a smaller set of 10 color digital fundus images from healthy older participants is also included. Comparison of the microvascular parameters of these two sets of images demonstrate that digital fundus images recorded with a hand-held portable camera are able to capture the changes in patterns of microvascular network associated with aging. The raw images from the TREND database provide a standard that defines normal retinal anatomy and microvascular network geometry in young healthy people in Montenegro as it is seen with the digital hand-held portable non-mydriatic MiiS HORUS Scope DEC 200.This knowledge could facilitate the application of this technology at the primary level of health care for large scale telematic screening for complications of chronic diseases, such as hypertensive and diabetic retinopathy. In addition, it could aid in the development of new methods for early detection of age-related changes in the retina, systemic chronic diseases, as well as eye-specific diseases. The associated manually segmented images of the microvascular networks provide the standard that can be used for development of automatic software for image quality assessment, segmentation of microvascular network, and for computer-aided detection of pathological changes in retina. The TREND database is freely available at https://doi.org/10.5281/zenodo.4521043.

Improving national surveillance of new HIV diagnoses

The purpose of national HIV surveillance is to track and summarize trends in newly diagnosed cases as an indicator of HIV transmission within Canada, and supports the development and evaluation of programs and policies for prevention, testing and delivery of care. Accurately capturing and interpreting trends in HIV diagnoses within national surveillance becomes complicated when there is movement of people within a country or when individuals are diagnosed with HIV prior to migrating to a new country. This has been identified as an issue in other countries, including Australia, New Zealand and Switzerland. The Public Health Agency of Canada (PHAC) recently assessed this in Canada after noting a rise in new HIV cases in Canada between 2014 to 2017. An environmental scan was conducted to better understand how new and previously diagnosed cases of HIV were recorded by and reported to PHAC from provincial and territorial (PT) public health authorities. It was discovered there was variation with respect to the reporting of cases who had received a new diagnosis of HIV within the province or territory, but who had previously received an HIV diagnosis from another PT or another country. Five PTs included cases previously diagnosed in another Canadian PT within the HIV surveillance data reported to PHAC and nine PTs included people who were diagnosed with HIV outside of Canada. The provincial and territorial public health authorities then reviewed HIV surveillance data from 2007 to 2017 to identify cases using a common definition of "previous HIV-positive test result". This included any case who gave a history, or had laboratory evidence, of an HIV-positive result from another PT or another country before presenting for care in the province or territory where they now resided. When these cases were subtracted from the total, a revised number of new HIV diagnoses was calculated for Canada. Re-analysis of surveillance data using this common definition for 2007 to 2017 explained more than half of the increase in HIV cases that had been documented in Canada over the last four years. In the future, national surveillance data will be calculated adopting this new common definition of a previous positive test result, in order to more accurately describe the trends in HIV transmission occurring in Canada.

HIV in Canada-Surveillance Report, 2018

BACKGROUND

Human immunodeficiency virus (HIV) is a global public health issue, with an estimated 36.9 million people living with HIV in 2017. HIV has been reportable in Canada since 1985 and the Public Health Agency of Canada (PHAC) continues to monitor trends in new HIV diagnoses.

OBJECTIVE

The objective of this surveillance report is to provide an overview of the epidemiology of all reported diagnoses of HIV in Canada since 1985 with a focus on 2018 overall, and by geographic location, age group, sex, and exposure category.

METHODS

PHAC monitors HIV through the national HIV/AIDS Surveillance System, a passive, case-based system that collates nonnominal data that is voluntarily submitted by all Canadian provinces and territories. Descriptive epidemiological analyses were conducted on national data and those relating to specific populations provided by Immigration, Refugees and Citizenship Canada and the Canadian Perinatal HIV Surveillance Program.

RESULTS

In 2018, a total of 2,561 HIV diagnoses were reported in Canada, an increase of 8.2% compared with 2017. The national diagnosis rate increased to 6.9 per 100,000 population in 2018 from 6.5 per 100,000 population in 2017. Saskatchewan reported the highest provincial diagnosis rate at 14.9 per 100,000 population. The 30-39 year age group continued to have the highest HIV diagnosis rate at 15.4 per 100,000 population. Overall, the diagnosis rate for males continued to be higher than that of females (9.8 versus 4.0 per 100,000 population, respectively); however, females experienced a larger increase in reported cases and diagnosis rate. The gay, bisexual and other men who have sex with men (gbMSM) exposure category continued to represent the highest proportion of all reported adult cases (41.4%), though the proportion has decreased over time. Five perinatal HIV transmissions were documented, three were related to the mother not receiving perinatal antiretroviral therapy prophylaxis.

CONCLUSION

The number and rate of reported HIV cases in Canada increased in 2018, gbMSM continued to account for the largest exposure category and the number and rate of reported HIV cases among women increased. PHAC will continue to work with its national partners to refine the collection, analysis and publication of national data to better understand the burden of HIV in Canada.

Regional Patterns in Retinal Microvascular Network Geometry in Health and Disease

The study explores the regional differences in microvascular geometry between the optic disc (O) and the macular area (M) in health and disease. Skeletonized manually segmented vascular networks from 15 healthy, 15 retinas with diabetic retinopathy (DR), and 15 retinas with glaucoma from publicly available High-Resolution Fundus (HRF) image database were used. When visualized by a digital fundus camera, O has a substantial proportion of small arteries and larger arterioles, while M contains smaller arterioles at the periphery and avascular zone in the center. We hypothesized that in pathological conditions the vascular network remodelling patterns in these two regions may be different. The analysis of box-counting fractal dimension (Db), lacunarity (Λ), and microvascular density showed that in healthy retinas, Λ and vessel density were lower in the M compared to the O, while the Db did not change. In retinas with DR, the Db was the lowest in the M, which was different from all other groups. The vessel density followed this trend. Lacunarity was the highest in the O of DR group compared to all other groups. The results show that in DR various regions of retinal microvascular network remodel in a different manner and to different extent.

Fractal characterization of retinal microvascular network morphology during diabetic retinopathy progression

OBJECTIVE

The study aimed to characterize morphological changes of the retinal microvascular network during the progression of diabetic retinopathy.

METHODS

Publicly available retinal images captured by a digital fundus camera from DIARETDB1 and STARE databases were used. The retinal microvessels were segmented using the automatic method, and vascular network morphology was analyzed by fractal parametrization such as box-counting dimension, lacunarity, and multifractals.

RESULTS

The results of the analysis were affected by the ability of the segmentation method to include smaller vessels with more branching generations. In cases where the segmentation was more detailed and included a higher number of vessel branching generations, increased severity of diabetic retinopathy was associated with increased complexity of microvascular network as measured by box-counting and multifractal dimensions, and decreased gappiness of retinal microvascular network as measured by lacunarity parameter. This association was not observed if the segmentation method included only 3-4 vessel branching generations.

CONCLUSIONS

Severe stages of diabetic retinopathy could be detected noninvasively by using high resolution fundus photography and automatic microvascular segmentation to the high number of branching generations, followed by fractal analysis parametrization. This approach could improve risk stratification for the development of microvascular complications, cardiovascular disease, and dementia in diabetes.

Morphometric characteristics of the optic canal and the optic nerve

BACKGROUND

The optic nerve (ON), a major component of the visual system, is divided into four segments: the intrabulbar (IB), the intraorbital (IO), the intraca- nalicular (ICn) and the intracranial (ICr). The ICr ends with the two nerves partially decussating in the optic chiasm (OCh). The purpose of this study is to provide a detailed description of the dimensions of the OC (the diameter and the surface area of its foramina and the central segment, as well as the length of the OC and the thickness of its walls) as well as the ON (the length of the ON segments, the diameter of the ICn segment of the ON, the angle of decussation in the OCh, as well as the distance between the two ON at the cranial foramen of the OC).

MATERIALS AND METHODS

The acquired data was then used to estimate the volu- me of the OC and the ICn segment of the ON. The morphometric research was performed on 25 cadavers (17 male and 8 female) and 30 skulls.

RESULTS

The surface area of the central segment of the OC was significantly smaller than the cranial foramen (p = 0.02) and the orbital foramen (p = 0.009). The inferior wall of the OC was significantly shorter than the other OC walls (p < 0.0001). The IO segment of the ON was the longest, where the difference to the ICn and ICr was statistically significant (p < 0.0001). The surface area of the ON at the cranial foramen was significantly larger than the surface area at the central segment of the OC (p = 0.02) and orbital foramen (p < 0.0001). The difference between the surface areas of the ON at the orbital foramen and the central segment of the OC was also statistically significant (p = 0.01). The estimated volume of the OC was calculated to be 190.72 mm3, and the volume of the ICn segment of the ON was estimated to be 50.25 mm3.

CONCLUSIONS

It is absolutely crucial to open the central segment of the OC when decompressing the ON, due to the narrowing of the OC in this segment.

Influenza A H1N1 virus infection among pregnant women in a tertiary hospital in Belgrade, Serbia

INTRODUCTION

Pregnant women are at higher risk of developing severe influenza. Our aim was to analyze clinical course and risk factors for fatal outcome in pregnant women with influenza (H1N1) infection.

METHODOLOGY

This retrospective study enrolled eleven pregnant women with confirmed Influenza A (H1N1) infection treated in the Clinic for Infectious and Tropical Diseases, Belgrade, Serbia in a 6-years period.

RESULTS

The mean age of pregnant women was 28.9 ± 5.2 years, and mean gestational age was 23.1 ± 7.0 weeks. Nine (81.8%) pregnant women had pneumonia (six had interstitial and three had bacterial pneumonia). Pregnant women developed pneumonia more often than other women in the reproductive period, but without statistical significance (81.8% vs. 65.7%, p = 0.330, OR (95% CI) 2.35 (0.47-11.80)). Nine (81.8%) pregnant women recovered. None of them experienced preterm delivery or abortion. Two women (18.2%) died due to acute respiratory distress syndrome. In one of them fetal death occurred one day before she died. The other one was performed caesarean section three days before death. Her newborn and children of all recovered women were healthy at birth. Prolonged time to initiation of oseltamivir and higher body mass index were statistically significantly associated with fatal outcome (p = 0.002, and p = 0.007, respectively). Gestational week of pregnancy, the etiology of pneumonia and comorbidity were not found to be risk factors for death (p = 0.128, p = 0.499 and p = 1.000, respectively).

CONCLUSION

Pregnant women with H1N1 infection are at higher risk of pneumonia and death than other women in the reproductive period. Early antiviral therapy reduces the risk of unfavorable outcome.

A Moodle-based blended learning solution for physiology education in Montenegro: a case study

This study evaluates the impact of web-based blended learning in the physiology course at the Faculty of Medicine, University of Montenegro. The two main goals of the study were: to determine the impact of e-learning on student success in mastering the course, and to assess user satisfaction after the introduction of e-learning. The study compared a group of students who attended the physiology course before, with a group of students who attended the physiology course after the Moodle platform was fully implemented as an educational tool. Formative and summative assessment scores were compared between these two groups. The impact of high vs. low Moodle use on the assessment scores was analyzed. The satisfaction among Moodle users was assessed by the survey. The study found that attendance of face-to-face lectures had a positive impact on academic performance. The introduction of Moodle in the presented model of teaching increased interest of students, attendance of face-to-face lectures, as well as formative and summative scores. High frequency of Moodle use was not always associated with better academic performance, suggesting that the introduction of a new method of teaching was most likely equally accepted by low- and high-achieving students. Most of the students agreed that Moodle was easy to use and it complemented traditional teaching very well, but it could not completely replace traditional face-to-face lectures. The study supports continuing the use of web-based learning in a form of blended learning for physiology, as well as for other courses in medical education.

Fractal dimension and lacunarity analysis of retinal microvascular morphology in hypertension and diabetes

Hypertension and diabetes mellitus represent modifiable risk factors for vascular disease. They cause microvascular remodeling, and ultimately result in end-organ damage. Therefore, development of methods for noninvasive quantification of the effects of hypertension and diabetes mellitus on microvasculature is of paramount importance. The two goals of the study were: 1) to characterize the geometric complexity and inhomogeneity of retinal vasculature in hypertensive retinopathy (HR) and in proliferative diabetic retinopathy (PDR) by using box counting fractal dimension and lacunarity analysis, and 2) to determine if the combination of these two parameters can be used to describe differences in the vascular tree geometry between HR and PDR. The extended set of retinal images from the publicly available STARE database was manually segmented by our expert, validated, and made available for other researchers to use. The healthy retinal vascular network has a higher complexity (fractal dimension) compared to that in HR and in PDR. However, there is no difference in microvascular complexity between HR and PDR. The inhomogeneity of the retinal microvascular tree (lacunarity) was higher in PDR compared to HR. Lacunarity and fractal dimension together quantitatively characterize microvascular geometry in the retina with higher specificity than fractal analysis alone.

Clinicopathological characteristics and survival in Serbian patients with renal cell carcinoma: a retrospective analysis

PURPOSE

Indications of kidney cancer outcome in lowerincome countries are based on an incidence/mortality ratio due to lack of survival information. This study was conducted to provide outcome data in Serbian patients with renal cell carcinoma (RCC) and to identify prognostic factors that could affect their overall survival (OS).

METHODS

This retrospective study included 185 patients who underwent nephrectomy. We assessed certain clinicopathological data including age, gender, tumor size, grade, stage and histological subtypes for their possible impact on OS.

RESULTS

The 5-year OS was 63.2%. Significant association was found between OS and age (log-rank 12.455, p=0.006), tumor size (log-rank 26.425, p=0.000), grade (log-rank 13.249, p=0.000) and stage (log-rank 43.235, p=0.000). Univariate analysis indicated size (p=0.000), grade (p=0.001) and stage (p=0.000) as prognostic factors for OS. In multivariate analysis, grade (p=0.014) and stage (p=0.000) remained significant predictors of OS.

CONCLUSION

Tumor grade and stage were identified as independent prognostic factors of OS survival in Serbian patients with RCC.

Global fibroblast activation throughout the left ventricle but localized fibrosis after myocardial infarction

Fibroblast (Fb) differentiation and interstitial fibrosis contribute to cardiac remodeling and loss of function after myocardial infarction (MI). We investigated regional presence and regulation of fibrosis in a pig MI model. In vivo analysis of regional function and perfusion defined three regions: the scar, the myocardium adjacent to the scar (MI_adjacent, reduced function, reduced perfusion reserve), and the remote myocardium (MI_remote, minimal functional deficit, maintained perfusion). Interstitial and perivascular fibrosis, and increase of collagen type I, was only observed in the MI_adjacent. Fb activated protein-alpha (FAP-α) was enriched in MI_adjacent compared to MI_remote. TGF-β1, which triggers Fb differentiation, was upregulated in both MI_adjacent and MI_remote, whereas lysyl oxidase, a regulator of collagen cross-linking, and the proteoglycans decorin and biglycan were only increased in the MI_adjacent. Fb isolated and cultured for 4 days had myoFb characteristics with little difference between MI_remote and MI_adjacent, although RNA sequencing revealed differences in gene expression profiles. Fbs from all regions maintained proliferative capacity, and induced contraction of 3-D collagen matrices but scar myoFb was more effective. These data suggest that after MI, signaling through TGF-β1, possibly related to increased mechanical load, drives Fb activation throughout the left ventricle while regional signaling determines further maturation and extracellular matrix remodeling after MI.

Combined reconstruction of atrial morphology and paracardial fat depositions to study remodeling in atrial fibrillation

Atrial fibrillation (AF) is the most frequent sustained cardiac arrhythmia. AF is shown to be a progressive disease, which is strongly associated with important structural (morphological and histological), electrical and mechanical remodeling of the left atrium (LA). Adipose tissue accumulation has been shown to be a risk factor in AF. We set out to explore the connection between adipose tissue coverage of the LA surface, for both the complete LA and specific regions and the progression of AF. In this study we propose a methodology to study the regional coverage of the left-atrial wall with adipose tissue based on magnetic resonance data. Validation was performed in a sheep model. While the total amount of left-atrial adipose tissue was higher in the sheep with AF, no changes in regional coverage were observed.

Complications of Laparoscopic Cholecystectomy: Our Experience from a Retrospective Analysis

AIM:

The aim of this study was to evaluate the intraoperative and postoperative complications of laparoscopic cholecystectomy, as well as the frequency of conversions.

MATERIAL AND METHODS:

Medical records of 740 patients who had laparoscopic cholecystectomy were analysed retrospectively. We evaluated patients for the presence of potential risk factors that could predict the development of complications such as age, gender, body mass index, white blood cell count and C-reactive protein (CRP), gallbladder ultrasonographic findings, and pathohistological analysis of removed gallbladders. The correlation between these risk factors was also analysed.

RESULTS:

There were 97 (13.1%) intraoperative complications (IOC). Iatrogenic perforations of a gallbladder were the most common complication - 39 patients (5.27%). Among the postoperative complications (POC), the most common ones were bleeding from abdominal cavity 27 (3.64%), biliary duct leaks 14 (1.89%), and infection of the surgical wound 7 patients (0.94%). There were 29 conversions (3.91%). The presence of more than one complication was more common in males (OR = 2.95, CI 95%, 1.42-4.23, p < 0.001). An especially high incidence of complications was noted in patients with elevated white blood cell count (OR = 3.98, CI 95% 1.68-16.92, p < 0.01), and CRP (OR = 2.42, CI 95% 1.23-12.54, p < 0.01). The increased incidence of complications was noted in patients with ultrasonographic finding of gallbladder empyema and increased thickness of the gallbladder wall > 3 mm (OR = 4.63, CI 95% 1.56-17.33, p < 0.001), as well as in patients with acute cholecystitis that was confirmed by pathohistological analysis (OR = 1.75, CI 95% 2.39-16.46, p < 0.001).

CONCLUSION:

Adopting laparoscopic cholecystectomy as a new technique for treatment of cholelithiasis, introduced a new spectrum of complications. Major biliary and vascular complications are life threatening, while minor complications cause patient discomfort and prolongation of the hospital stay. It is important recognising IOC complications during the surgery so they are taken care of in a timely manner during the surgical intervention. Conversion should not be considered a complication.

Health-related quality of life in children and adolescents with type 1 diabetes mellitus from Montenegro: relationship to metabolic control

BACKGROUND

The aim of this study was to evaluate health-related quality of life (HRQOL) in children and adolescents with type 1 diabetes (TIDM) in Montenegro compared with healthy controls and to estimate the effect of metabolic control on perceptions of HRQOL.

METHODS

This study involved children and adolescents with T1DM, age- and gender-matched healthy children and their parents. Children and adolescents with T1DM and their parents completed Peds QL 4.0 Generic Core Scales (GCS) and PedsQL 3.0 Diabetes Module. Healthy children and their parents completed self- and proxy-report of Peds QL 4.0 GCS.

RESULTS

Our study (self- and proxy-report) showed that children and adolescents with T1DM had lower HRQOL on domain "Psychosocial health" and "School functioning" compared with healthy population (p=0.008; p≤0.001). Lower glycosylated hemoglobin (HbAlc) values were associated with fewer worries, and better health perception by diabetic children and their parents. We did not find notable differences between boys and girls on health perception. Different age groups reported similar QOL. Parents reported that the illness has a greater impact on children's lives than the children reported themselves.

CONCLUSIONS

Compared with the healthy children, the HRQOL was lower among children and adolescents with T1DM. Lower HbA1c was associated with better quality of life.

Antioxidant Enzymes in Brain Cortex of Rats Exposed to Acute, Chronic and Combined Stress

The study deals with manganese superoxide dismutase, copper, zinc superoxide dismutase, and catalase activities in brain cortex of Wistar rats exposed to acute stress (immobilization or cold for 2 h), chronic stress (long-term isolation or long-term forced swimming for 21 days), or to combined chronic/acute stress. We observed that i) single episodes of acute stress by immobilization increased activity of both superoxide dismutases; ii) both types of chronic stresses significantly elevated activities of all examined enzymes; iii) chronic social isolation was a much stronger stressor than physical stress by swimming; iv) in animals pre-exposed to chronic isolation, additional stress by immobilization or cold significantly decreased previously elevated activities of all enzymes, while after chronic swimming, acute immobilization lowered only catalase activity. The obtained results indicate that stress conditions most probably altered the cell redox equilibrium, thus influencing the antioxidant response in brain cortex. Further investigation of neuronal prooxidant/antioxidant cellular conditions is needed to improve the prevention and treatment of various stress induced diseases.

Oral teicoplanin for successful treatment of severe refractory Clostridium difficile infection

INTRODUCTION

Clostridium difficile is the leading cause of hospital-acquired diarrhoea. There is no defined protocol for treating severe Clostridium difficile infection (CDI) refractory to vancomycin or vancomycin and metronidazole combination therapy. The aim of this study was to evaluate the rate of clinical cure, time to resolution of diarrhoea and recurrence rate in patients with severe refractory CDI treated with oral teicoplanin.

METHODOLOGY

A one-year prospective study was carried out in the Clinic for Infectious and Tropical Diseases, Clinical Center Serbia. Patients with severe and complicated CDI who failed to respond to oral vancomycin and intravenous metronidazole combination therapy were enrolled. They were given oral teicoplanin 100 mg bi-daily. Patients were followed for recurrence for eight weeks.

RESULTS

Nine patients with a mean age of 70.8±9.4 years were analyzed. All patients had pseudomembranous colitis, and five had complicated disease. In four patients intracolonic delivery of vancomycin was also performed in addition to oral vancomycin and intravenous metronidazole prior to initiating teicoplanin, but without improvement. After teicoplanin initiation all patients achieved clinical cure. The mean time to resolution of diarrhoea after teicoplanin introduction was 6.3±4.5 days. There was no statistically significant difference in time to resolution of diarrhoea according to initial leucocyte count, age over 65 years, the presence of ileus, complicated disease and the use of concomitant antibiotic therapy (p = 0.652, 0,652, 0.374, 0.374, and 0,548, respectively). None of the patients experienced recurrence.

CONCLUSIONS

Oral teicoplanin might be a potential treatment for severe and complicated refractory CDI, but further studies are required.

Seroprevalence and risk factors for hepatitis C virus infection among blood donors in Serbia: A multicentre study

BACKGROUND

The epidemiological characteristics of hepatitis C virus (HCV) infection have not yet been described in Serbia.

AIMS

To determine the prevalence of anti-HCV-positive individuals among first-time blood donors and the risk factors for hepatitis C transmission.

METHODS

A multicentre case-control study nested within a prospective cohort study was conducted at 10 main transfusion centres in Serbia in 2013 and 27,160 blood donors who gave blood for the first time were included. Blood donors with confirmed anti-HCV positivity and seronegative controls were enrolled to determine the risk factors.

RESULTS

Of 27,160 blood donors 52 were anti-HCV-positive; seroprevalence was 0.19%. By univariate analysis, marital status, educational level, drug use, previous transfusion, tattooing, non-use of condoms and number of sexual partners, were risk factors for hepatitis C. In the final multivariate analysis, three factors remained independently predictive: drug use, tattooing and previous blood transfusion. In total, 87.5% of cases had at least one of the risk factors for HCV transmission; 20.9% presumed that they knew when the infection occurred.

CONCLUSION

HCV seroprevalence in Serbia is higher than in developed European countries. Preventive measures need to be directed towards drug use and tattooing facilities. The admission questionnaire for blood donors should be improved.

Clostridium difficile infection: a Serbian single-center experience

INTRODUCTION

Clostridium difficile infection (CDI) is the most common cause of hospital-acquired diarrhea. Severity of CDI is associated with advanced age and co-morbidities. The clinical spectrum varies from mild watery diarrhea to severe fulminant pseudomembranous colitis with complications.

METHODOLOGY

This study conducted over a six-year period (2008 to 2013) included 510 patients treated at the University Hospital for Infectious and Tropical Diseases in Belgrade, Serbia. In patients with a history of previous hospitalization and/or treatment with antimicrobial agents who developed diarrhea, the diagnosis was established with rapid tests for C. difficile toxin A and B and by stool culture for C. difficile (454 patients) or by endoscopic examination and histological analyses of the biopsy samples taken from the colonic mucosa (56 patients).

RESULTS

The mean age of patients was 67.71±13.34 years. A total of 67.8% patients were older than 65 years. Over half (58.7%) of the patients were female. 93% had been previously hospitalized and/or had surgical interventions, during which they had been treated with antibiotics. In the clinical presentation spectrum, pseudomembranous colitis occurred in 51.0%. The mean duration of illness after the introduction of specific antibiotic therapy was 7.10 ± 4.88 days. Complications developed in 14 patients. The disease relapsed in 43 (8.4%). Thirty-two (6.3%) patients died, mostly due to co-morbidities.

CONCLUSIONS

CDI is the most important cause of hospital-acquired diarrhea in Serbia. The disease mainly affects elderly patients with co-morbidities. The incidence of complications is low and prognosis is age dependent and related to pre-existing diseases.

Automatic mitral annulus tracking in volumetric ultrasound using non-rigid image registration

Analysis of mitral annular dynamics plays an important role in the diagnosis and selection of optimal valve repair strategies, but remains cumbersome and time-consuming if performed manually. In this paper we propose non-rigid image registration to automatically track the annulus in 3D ultrasound images for both normal and pathological valves, and compare the performance against manual tracing. Relevant clinical properties such as annular area, circumference and excursion could be extracted reliably by the tracking algorithm. The root-mean-square error, calculated as the difference between the manually traced landmarks (18 in total) and the automatic tracking, was 1.96 ± 0.46 mm over 10 valves (5 healthy and 5 diseased) which is within the clinically acceptable error range.

Regional changes in elastic fiber organization and transforming growth factor β signaling in aortas from a mouse model of marfan syndrome

In Marfan Syndrome (MFS), development of thoracic aortic aneurysms (TAAs) is characterized by degeneration of the medial layer of the aorta, including fragmentation and loss of elastic fibers, phenotypic changes in the smooth muscle cells, and an increase in the active form of transforming growth factor-β (TGFβ), which is thought to play a major role in development and progression of the aneurysm. We hypothesized that regional difference in elastic fiber fragmentation contributes to TGFβ activation and hence the localization of aneurysm formation. The fibrillin-1-deficient mgR/mgR mouse model of MFS was used to investigate regional changes in elastin fiber fragmentation, TGFβ activation and changes in gene expression as compared to wild-type littermates. Knockdown of Smad 2 and Smad 3 with shRNA was used to determine the role of the specific transcription factors in gene regulation in aortic smooth muscle cells. We show increased elastin fiber fragmentation in the regions associated with aneurysm formation and altered TGFβ signaling in these regions. Differential effects of Smad 2 and Smad 3 were observed in cultured smooth muscle cells by shRNA-mediated knockdown of expression of these transcription factors. Differential signaling through Smad 2 and Smad 3 in regions of active vascular remodeling likely contribute to aneurysm formation in the mgR/mgR model of MFS. Increased elastin fiber fragmentation in these regions is associated with these changes as compared to other regions of the thoracic aorta and may contribute to the changes in TGFβ signaling in these regions.

Time course of carotid artery growth and remodeling in response to altered pulsatility

Elucidating early time courses of biomechanical responses by arteries to altered mechanical stimuli is paramount to understanding and eventually predicting long-term adaptations. In a previous study, we reported marked long-term (at 35-56 days) consequences of increased pulsatile hemodynamics on arterial structure and mechanics. Motivated by those findings, we focus herein on arterial responses over shorter periods (at 7, 10, and 14 days) following placement of a constrictive band on the aortic arch between the innominate and left carotid arteries of wild-type mice, which significantly increases pulsatility in the right carotid artery. We quantified hemodynamics in vivo using noninvasive ultrasound and measured wall properties and composition in vitro using biaxial mechanical testing and standard (immuno)histology. Compared with both baseline carotid arteries and left carotids after banding, right carotids after banding experienced a significant increase in both pulse pressure, which peaked at day 7, and a pulsatility index for velocity, which continued to rise over the 42-day study despite a transient increase in mean flow that peaked at day 7. Wall thickness and inner diameter also increased significantly in the right carotids, both peaking at day 14, with an associated marked early reduction in the in vivo axial stretch and a persistent decrease in smooth muscle contractility. Glycosaminoglycan content also increased within the wall, peaking at day 14, whereas increases in monocyte chemoattractant protein-1 activity and the collagen-to-elastin ratio continued to rise. These findings confirm that pulsatility is an important modulator of wall geometry, structure, and properties but reveal different early time courses for different microscopic and macroscopic metrics, presumably due to the separate degrees of influence of pressure and flow.

Site-specific and dose-dependent effects of glucocorticoid receptor phosphorylation in yeast Saccharomyces cerevisiae

The glucocorticoid receptor (GR) signal transduction and transcriptional regulation are efficiently recapitulated when GR is expressed in Saccharomyces cerevisiae. In this report we demonstrate that the in vivo GR phosphorylation pattern, hormone dependency and interdependency of phosphorylation events were similar in yeast and mammalian cells. GR phosphorylation at S246 exhibited inhibitory effect on S224 and S232 phosphorylation, suggesting the conservation of molecular mechanisms that control this interdependence between yeast and mammalian cells. To assess the effects of GR phosphorylation the mutated GR derivatives T171A, S224A, S232A, S246A were overexpressed and their transcriptional activity was analysed. These receptor derivatives displayed significant hormone inducible transcription when overexpressed in S. cerevisiae. We have established an inducible methionine expression system, which allows the close regulation of the receptor protein levels to analyse the dependence of GR function on its phosphorylation and protein abundance. Using this system we observed that GR S246A mutation increased its activity across all of the GR concentrations tested. The activity of the S224A and S246A mutants was mostly independent of GR protein levels, whereas the WT, T171A and S232A mediated transcription diminished with declining GR protein levels. Our results suggest that GR phosphorylation at specific residues affects its transcriptional functions in a site selective manner and these effects were directly linked to GR dosage.

Transforming growth factor-beta signaling in hypertensive remodeling of porcine aorta

A porcine aortic coarctation model was used to examine regulation of gene expression in early hypertensive vascular remodeling. Aortic segments were collected proximal (high pressure) and distal (low pressure) to the coarctation after 2 wk of sustained hypertension (mean arterial pressure>150 mmHg). Porcine 10K oligoarrays used for gene expression profiling of the two regions of aorta revealed downregulation of cytoskeletal and upregulation of extracellular region genes relative to the whole genome. A genomic database search for transforming growth factor-beta (TGF-beta) control elements showed that 19% of the genes that changed expression due to hypertension contained putative TGF-beta control elements. Real-time RT-PCR and microarray analysis showed no change in expression of TGF-beta1, TGF-beta2, TGF-beta3, or bone morphogenetic proteins-2 and -4, yet immunohistochemical staining for phosphorylated SMAD2, an indicator of TGF-beta signaling, and for phosphorylated SMAD1/5/8, an indicator of signaling through the bone morphogenetic proteins, showed the highest percentage of positively stained cells in the proximal aortic segments of occluded animals. For TGF-beta signaling, this increase was significantly different than for sham-operated controls. Western blot analysis showed no difference in total TGF-beta1 protein levels with respect to treatment or aortic segment. Immunohistochemistry showed that the protein levels of latency-associated peptide was decreased in proximal segments of occluded animals. Collectively, these results suggest that activation of TGF-beta, but not altered expression, may be a major mechanism regulating early hypertensive vascular remodeling.

Surface resistivity estimation by scanning surface potential microscopy

Nickel was sputter deposited on a glass with a thin film thickness of 600 nm under either in an argon atmosphere or under a partial pressure of nitrogen of either 1.3 x 10(-4) or 4 x 10(-4) mbar. Atomic force microscopy and scanning surface potential microscopy (SSPM) were used to study the morphology and to estimate the surface resistivity of the obtained Ni thin films taking into account surface-roughness effects. For the three samples investigated, the surface resistivity values as estimated using SSPM were in good agreement with the results obtained by standard four-point probe measurements.

Aberrant crypt foci and semiparametric modeling of correlated binary data

Motivated by the spatial modeling of aberrant crypt foci (ACF) in colon carcinogenesis, we consider binary data with probabilities modeled as the sum of a nonparametric mean plus a latent Gaussian spatial process that accounts for short-range dependencies. The mean is modeled in a general way using regression splines. The mean function can be viewed as a fixed effect and is estimated with a penalty for regularization. With the latent process viewed as another random effect, the model becomes a generalized linear mixed model. In our motivating data set and other applications, the sample size is too large to easily accommodate maximum likelihood or restricted maximum likelihood estimation (REML), so pairwise likelihood, a special case of composite likelihood, is used instead. We develop an asymptotic theory for models that are sufficiently general to be used in a wide variety of applications, including, but not limited to, the problem that motivated this work. The splines have penalty parameters that must converge to zero asymptotically: we derive theory for this along with a data-driven method for selecting the penalty parameter, a method that is shown in simulations to improve greatly upon standard devices, such as likelihood crossvalidation. Finally, we apply the methods to the data from our experiment ACF. We discover an unexpected location for peak formation of ACF.

Postoperative complications--massive transfusions in radical malignant gynecological surgeries

At the Institute of Gynecology and Obstetrics we examined 24 women who were radically operated on and received massive transfusions during the intraoperative and postoperative period. Twelve developed massive transfusion complications such as urticaria, fever, and respiratory insufficiency known as TRALI (transfusion-related acute lung injury).

Cervical and duodenal polyps and their malignant alterations--case report

During routine examination of a 32-year-old patient, a cervical polyp was found and CIN III was confirmed by biopsy. After performing colposcopy, biopsy and establishing CIN III as well as performing gastroscopy where a duodenal polyp was found, thorough diagnostic exams and therapy were carried out. Complete duodenal resection and conization were performed. The medical board decided that neither further radiation nor chemotherapy was needed.

Increased AFP as an indicator of ovarian carcinoma and fetal kidney carcinoma--case report

We examined a young primipara with increased alpha-fetoprotein (AFP) values and cystic tumefaction of the right ovary. Having in mind a mild decrease in ovarian artery resistance index (RI) and suspected findings of fetal kidney, this situation was delicate due to its double pathology which was later confirmed. Wilms' tumor is the most common urogenital tumor in childhood, and it is detectable in the prenatal period by ultrasound examination. In utero kidney biopsy confirms diagnosis and facilitates decisions concerning the course of pregnancy. Relative risk of intervention limits this diagnostic procedure for indicated cases.

Therapeutic potential of controlled drug delivery systems in neurodegenerative diseases

Several compounds that exhibit a therapeutic effect in experimental models of neurodegenerative diseases have been identified over recent years. Safe and effective drug delivery to the central nervous system is still one of the main obstacles in translating these experimental strategies into clinical therapies. Different approaches have been developed to enable drug delivery in close proximity to the desired site of action. In this review, we describe biodegradable polymeric systems as drug carriers in models of neurodegenerative diseases. Biomaterials described for intracerebral drug delivery are well tolerated by the host tissue and do not exhibit cytotoxic, immunologic, carcinogenic or teratogenic effects even after chronic exposure. Behavioral improvement and normalization of brain morphology have been observed following treatment using such biomaterials in animal models of Parkinson's, Alzheimer's and Huntington's diseases. Application of these devices for neuroactive drugs is still restricted due to the relatively small volume of tissue exposed to active compound. Further development of polymeric drug delivery systems will require that larger volumes of brain tissue are targeted, with a controlled and sustained drug release that is carefully controlled so it does not cause damage to the surrounding tissue.

Torsion of carcinomatous ovarian cyst and polycystic omental diseases--case report

A middle-aged patient, without any positive personal or familial history was urgently hospitalized and, after primary diagnostic procedures, treated by surgery for torsion and acute abdomen. During the procedure, torsioned ovarian cyst and a probable perforated omental cyst were found. Primary ovarian cancer and secondary polycystic metastatic echoes of the omentum were established by histopathology.

The incidence of vulvar pathology and vulvectomy within risk and non-risk groups

At the Institute of Gynecology and Obstetrics over a period of five years, more than 180,000 women were examined; 580 simple and 178 radical vulvectomies were performed.

Endometriosis and possible malignant transformation

By examining the cause of infertility for a the period of three years in the two largest hospitals in Belgrade, we found 453 cases of endometriosis out of 683 cases of laparoscopy. During the procedure, removal of endometrial foci, histological examination of the sample and removal of genital and peritoneum abnormalities by laser were carried out. Interestingly, in only 8% of the cases were cancerous changes of the ovary diagnosed. Out of 36 patients with established diagnoses, hysterectomy and bilateral salpingo-oophorectomy were performed in four cases.

Metastases of the digestive tract and ovarian tumors--or vice versa: an analysis

Ovarian carcinoma may appear regardless of age, including during childhood. Predisposing factors for the development of ovarian carcinoma are age (usually over 40), positive family history, mumps parotitis, small number of deliveries, environmental factors, persistant ovulation, etc. Metastases may appear in the ovary from almost all primary sites.

Vaginal malignant melanoma in a healthy pregnancy--a case report

Vaginal melanomas account for fewer than 2% of vaginal malignancies. The mean age at diagnosis is 55 years and the prognosis is poor, with an overall 5-year survival rate of 5% to 10%.

Tissue-specific attenuation of endogenous DNA I-compounds in rats by carcinogen azoxymethane: possible role of dietary fish oil in colon cancer prevention

I-compounds are bulky covalent DNA modifications that are derived from metabolic intermediates of nutrients. Some I-compounds may play protective roles against cancer, aging, and degenerative diseases. Many carcinogens and tumor promoters significantly reduce I-compound levels gradually during carcinogenesis. Colon cancer is the second leading cause of cancer death in the United States, whereas cancer of the small intestine is relatively rare. Here we have studied levels of I-compounds in DNA of colon and duodenum of male Sprague-Dawley rats treated with azoxymethane. The effects of dietary lipids (fish oil or corn oil) on colon and duodenal DNA I-compounds were also investigated. Rats fed a diet containing fish oil or corn oil were treated with 15 mg/kg azoxymethane. Animals were terminated 0, 6, 9, 12, or 24 hours after injection. I-compound levels were analyzed by the nuclease P1-enhanced (32)P-postlabeling assay. Rats treated with azoxymethane displayed lower levels of I-compounds in colon DNA compared with control groups (0 hour). However, I-compound levels in duodenal DNA were not diminished after azoxymethane treatment. Animals fed a fish oil diet showed higher levels of I-compounds in colonic DNA compared with corn oil groups (mean adduct levels for fish and corn oil groups were 13.35 and 10.69 in 10(9) nucleotides, respectively, P = 0.034). Taken together, these results support claims that fish oil, which contains a high level of omega-3 polyunsaturated fatty acids, may have potent chemopreventive effects on carcinogen-induced colon cancer. The fact that duodenal I-compounds were not diminished by azoxymethane treatment may have been due to the existence of tissue-specific factors protecting against carcinogenesis. In conclusion, our observations show that endogenous DNA adducts may serve not only as sensitive biomarkers in carcinogenesis and cancer prevention studies, but are also helpful to further our understanding of the chemopreventive properties of omega-3 fatty acids and mechanisms of carcinogenesis.

[Ankle sprain. Management of recent lesions and prevention of secondary instability]

Ankle sprains are among the most common musculoskeletal injuries. The vast majority of these injuries are lateral ligament sprains, resulting from inversion of the plantar-flexed foot. Initial management should include rest, ice, compression and elevation. Functional treatment proved to provide the quickest recovery and an earlier return to work without compromising the lateral mechanical stability. Surgical management of acute ankle sprains is rarely, if ever, indicated. Patients who continue to sustain multiple recurrent inversion sprains despite a supervised rehabilitation program aimed at improving proprioception and strengthening of the peroneal muscles are candidate for surgical reconstruction of the lateral ankle ligaments.

Detection of gastrointestinal and abdominal infections by 99mTc-ciprofloxacin

BACKGROUND/AIMS

The aim of the study is detection and evaluation of the abdominal and gastrointestinal infective foci using 99mTc-ciprofloxacin (Laboratory for radioactive isotopes, Vinca).

METHODOLOGY

In total 21 patients with clinical suspicion on abdominal or gastrointestinal infection were investigated. In all the patients, planar liver/spleen scintigraphy was performed. Ciprofloxacin chloride (3.5 mg) was mixed with 555 MBq of 99mTc in 3 mL of physiological solution and incubated for 20 min. After slow i.v. injection in a cubital vein, dynamic acquisition (1 f/min) was performed during the first 60 min in the position of interest, followed by static acquisition (500,000 imp) anterior and posterior view, abdomen and pelvis after 1 h and 4 h in all patients. When necessary, additional scintigrams were acquired after 24 h. In all the patients with negative or equivocal findings of planar scintigraphy, emission computerized tomography (SPECT) was performed (60 positions, 6 degrees). Interpretation was made by three independent observers. Additional data were provided using clinical findings, ultrasonography, computed tomography and magnetic resonance imaging, laboratory analyses, and surgical or microbiological confirmation of infection.

RESULTS

There were eleven true-positive findings, seven true negative, two were false negative while one was false positive due to intestinal obstruction. Sensitivity was 79%, specificity 91%, positive predictive value 92%, negative predictive value 77%, accuracy 84%.

CONCLUSIONS

According to our results, scintigraphy with radiolabeled ciprofloxacin is a useful method for detection and assessment of exact localization of abdominal and gastrointestinal infections.

Testing for spatial correlation in nonstationary binary data, with application to aberrant crypt foci in colon carcinogenesis

In an experiment to understand colon carcinogenesis, all animals were exposed to a carcinogen, with half the animals also being exposed to radiation. Spatially, we measured the existence of what are referred to as aberrant crypt foci (ACF), namely, morphologically changed colonic crypts that are known to be precursors of colon cancer development. The biological question of interest is whether the locations of these ACFs are spatially correlated: if so, this indicates that damage to the colon due to carcinogens and radiation is localized. Statistically, the data take the form of binary outcomes (corresponding to the existence of an ACF) on a regular grid. We develop score-type methods based upon the Matern and conditionally autoregressive (CAR) correlation models to test for the spatial correlation in such data, while allowing for nonstationarity. Because of a technical peculiarity of the score-type test, we also develop robust versions of the method. The methods are compared to a generalization of Moran's test for continuous outcomes, and are shown via simulation to have the potential for increased power. When applied to our data, the methods indicate the existence of spatial correlation, and hence indicate localization of damage.

Anterior knee pain with a posterior-stabilized mobile-bearing knee prosthesis: the effect of femoral component design

Femoropatellar problems have been reported with some designs of posterior-stabilized knee prostheses with fixed bearings; we report similar findings with a posterior-stabilized mobile-bearing prosthesis. A review of 184 patients (193 knees) who underwent placement of a Rotaglide (Corin, Cirencester, UK) posterior-stabilized prosthesis with patellar resurfacing showed that only 33 knees (17%) had complete absence of femoropatellar complaints after at least 1 year of follow-up evaluation. Femoropatellar grinding was noted in the other 160 knees; 65 were asymptomatic, 78 were mildly symptomatic, and 17 were severely symptomatic. Two patients refused secondary treatment; 15 underwent arthroscopic debridement. The only abnormal finding was intra-articular fibrosis surrounding the patellar implant. After arthroscopic debridement of the fibrosis, all patients reported immediate relief of their symptoms followed by recurrence within 6 to 9 months. Inappropriate trochlear design of the femoral implant appears to be the main determinant of femoropatellar problems in these patients. Encroachment on the trochlea by a broad intercondylar box with a sharp anterior edge appears detrimental to function irrespective of the presence or absence of bearing mobility.

Hyperextension trauma to the elbow: radiological and ultrasonographic evaluation in handball goalkeepers

OBJECTIVE

To detect elbow lesions produced by hyperextension in 30 elite handball goalkeepers.

METHODS

Conventional radiographs, stress radiographs, and ultrasound examination of both elbows were used. As a control group, 30 male volunteers from the general population within the same age group with no history of elbow injury were used.

RESULTS

Radiographic findings in the goalkeepers were osteophyte formation in 67%, loose bodies in 5.5%, and periarticular calcification in 5.5%. Significantly greater differences in medial joint space opening between stressed and unstressed elbows were measured in both elbows than in the control group. Ultrasonographic findings showed thickening of the medial collateral ligament in 50%, thickening of the tricipital tendon in 11%, and signs of ulnar neuritis in 22%. An intra-articular effusion was found in 66% and small loose bodies in 33%. No significant differences were found between the dominant and non-dominant elbows at radiological and ultrasound examination. The findings in the control group were normal.

CONCLUSIONS

The findings support the theory that repetitive hyperextension trauma to the elbow in handball goalkeepers results in pathological changes.