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Biomedical subjects

A Todorov

Publications and source records attributed to A Todorov.

At least 19 recordsLinked to original sources
PubMed2003

[Ambulatory long-term management of a left ventricular assist device. Current modality in terminal heart failure].

We report about the first use and successful outpatient therapy with an implantable pulsatile left ventricular assist device (LVAD, Novacor) in a patient with a combined dilative and ischemic cardiomyopathy in Switzerland. The patient, a 51 year old man (112 kg, 191 cm, blood type A) developed end-stage heart failure (New York Heart Association class (NYHA) IV) while he was awaiting orthotopic heart transplantation. Due to his profession as an independent graphic-designer the patient was afraid of a long-term temporary disablement with consecutive bankruptcy. Therefore we decided and performed the implantation of a Novacor-LVAD as a bridge to transplantation with the possibility to outpatient therapy in a favourable course. The patient was supported by the device for more than five months. His cardiac functional status returned to NYHA class I, and the patient was discharged 5 weeks after implantation. He returned into his normal life and started working at 100% again. Furthermore the LVAD enabled the patient to participate in almost all activities. Five months (151 days) after implantation a donor organ became available and the patient underwent orthotopic heart transplantation. The use and successful outpatient therapy with an implantable pulsatile left ventricular assist device in our patient has proved to be save, reliable, life-saving, quality of life improving and could be an important alternative for the economic burden in heart failure therapy.

Activities of Daily Living↗
PubMed2003

[Swiss surgery: quo vadis? Reader and market analysis for strategic positioning of a specialty journal].

UNLABELLED: Scientific journals currently face challenges including cost pressures caused by economic constraints, increasing rivalry among competitors, limited market potential of non-english speaking journals, increasing medical specialization with resulting market fragmentation, and internet-based competition. We therefore analyzed strategic opportunities of the journal Swiss Surgery on the basis of customer surveys and of a market analysis. RESULTS: Swiss surgeons expressed their interest in the continuation of the journal but also indicated their support for changes in its concept and for an increased use of electronic media. An international market analysis points-out the difficulties of national, non-english speaking journals in gaining impact points and in attracting authors and readers of scientific medical articles. Therefore, a journal such as Swiss Surgery should identify and use publication niches. RECOMMENDATION: The demand for a concept addressing surgical training including continuous postgraduate education was confirmed by the customers of Swiss Surgery. A corresponding offer does not presently exist in the area and could become the new focus of the journal. This change of concept may have a number of consequences: A journal focusing on surgical training and education should use the results of readers' surveys rather than impact point assignment to evaluate quality. The journal should increasingly use electronic services including data bases, pictures, videos and closed user groups to supplement the print version. At short term, however, the printed version should be continued and not be substituted by the electronic version in order to maintain the established brand "Swiss Surgery".

Attitude of Health Personnel↗
PubMed2001

The effect of prone positioning on intraocular pressure in anesthetized patients.

BACKGROUND: Ocular perfusion pressure is commonly defined as mean arterial pressure minus intraocular pressure (IOP). Changes in mean arterial pressure or IOP can affect ocular perfusion pressure. IOP has not been studied in this context in the prone anesthetized patient. METHODS: After institutional human studies committee approval and informed consent, 20 patients (American Society of Anesthesiologists physical status I-III) without eye disease who were scheduled for spine surgery in the prone position were enrolled. IOP was measured with a Tono-pen XL handheld tonometer at five time points: awake supine (baseline), anesthetized (supine 1), anesthetized prone (prone 1), anesthetized prone at conclusion of case (prone 2), and anesthetized supine before wake-up (supine 2). Anesthetic protocol was standardized. The head was positioned with a pinned head-holder. Data were analyzed with repeated-measures analysis of variance and paired t test. RESULTS: Supine 1 IOP (13 +/- 1 mmHg) decreased from baseline (19 +/- 1 mmHg) (P < 0.05). Prone 1 IOP (27 +/- 2 mmHg) increased in comparison with baseline (P < 0.05) and supine 1 (P < 0.05). Prone 2 IOP (40 +/- 2 mmHg) was measured after 320 +/- 107 min in the prone position and was significantly increased in comparison with all previous measurements (P < 0.05). Supine 2 IOP (31 +/- 2 mmHg) decreased in comparison with prone 2 IOP (P < 0.05) but was relatively elevated in comparison with supine 1 and baseline (P < 0.05). Hemodynamic and ventilatory parameters remained unchanged during the prone period. CONCLUSIONS: Prone positioning increases IOP during anesthesia. Ocular perfusion pressure could therefore decrease, despite maintenance of normotension.

Adolescent↗
PubMed2000

Aberrant right pulmonary artery and double outlet ventricle: one-stage repair.

We report a 13-month-old male child with anomalous origin of the right pulmonary artery from the ascending aorta and a double outlet right ventricle. Aortic wall was used for elongation of the pulmonary artery and side-to-end connection to the pulmonary trunk. Special emphasis is made on this particular operative technique for strictly laterally originating right pulmonary artery that requires no prosthetic material, avoids extreme stretching, and may enable normal growth potential.

Aorta↗
PubMed2000

The accessibility and applicability of knowledge: predicting context effects in national surveys.

Using data from the National Health Interview Survey on Disability from 1994 and 1995, this research demonstrates that the size of accessibility effects (increased likelihood of using information activated by initial questions in responding to subsequent questions) can be modeled as a function of the applicability of the initial to the subsequent questions. When respondents reported a disability and were asked about the main condition causing the disability, they were more likely to report conditions they had been asked about earlier in the interview than alternative conditions. This accessibility effect was inversely related to the effect on reports of "other" or unclassifiable conditions. The more reports of primed conditions, the fewer reports of unclassifiable conditions. A log-linear model of the accessibility bias fit the data for all disabilities. For reports of specific conditions, a measure of the applicability of context accounted for 74.4 percent of the variance of the accessibility bias; for unclassifiable or "other" conditions, it accounted for 61 percent. When limited to "well-defined" disabilities, applicability accounted for 91.9 percent of the variance (a multiple correlation of.96). Finally, models of the context effects derived from the 1994 data were tested against the actual effects for the 1995 data. The correlation between predicted and actual effects was.80 across disabilities. The theoretical and the practical implications of the findings are discussed.

Journal Article↗
PubMed2000

Bias in proxies' reports of disability: data from the National Health Interview Survey on disability.

OBJECTIVES: These studies examined whether differences between self-reports and proxy reports of disabilities reflect proxy response biases or only respondent selection factors. METHODS: The data were from the National Health Interview Survey on Disability (1994-1995, phases 1 and 2). In study 1, reports of disabilities were regressed on respondent status, self vs proxy, and demographic factors. In study 2, the ratios of the proportions of self-reports and proxy reports of disabilities were regressed on independent lay ratings of observability of these disabilities and their "interactional" nature. In study 3, the disability reports for people who differed in respondent status in one phase but self-reported the same disability in the other phase were compared. RESULTS: In study 1, proxies under-reported disabilities for people aged 18 to 64 years but overreported for people 65 years or older. In study 2, the observability and interactional scores accounted for more than 60% of the variance of self and proxy differences in an inverse relationship, study 3 confirmed the basic findings of study 1. CONCLUSIONS: Use of proxies in representative surveys on disability introduces systematic biases, affecting national disability estimates.

Activities of Daily Living↗
PubMed2000

[Reverse remodeling by surgery--fact or fiction?].

Mortality of chronic heart failure in industrial countries remains unacceptably high despite advances in medical therapy. Heart transplantation, the gold standard in the treatment of end-stage heart failure is reserved for only a few patients because of the shortage of donor hearts. Surgical alternatives to transplantation include dynamic cardiomyoplasty (CMP), mitral valve reconstruction, left ventricular reduction surgery (PLVR) and ventricular assist devices (VAD). Improved survival and objective physiologic improvement have not been documented for CMP in the treatment of dilative cardiomyopathy. Mitral valve reconstruction on the other hand shows promising results. PLVR is an innovative procedure in which the heart is surgically reduced in size and cardiac function is dramatically improved immediately after surgery. The presence of long-term effects is still unknown. VAD have been shown to be extremely effective as a short- and long-term "bridge" to heart transplantation. They are not approved for permanent support. A randomized trial in the U.S. is underway to compare the efficacy of these devices with the efficacy of medical therapy in NYHA functional class IV patients in quality of life, survival and costs.

Cardiomyoplasty↗
PubMed2000

[Cytokines and the liver in health and disease].

Cytokines are a group of proteins with autocrine, paracrine and endocrine activities which provide communication among hepatic cells and other cells and tissues of the man. Active in minute quantities, the cytokines activate and regulate homeostasis and cellular repair through effects on cell growth, differentiation and receptor expression and cell-mediated immunity. Cytokines--IL-1, IL-2, IL-6, IL-8 IL-10, IL-12, TNF-alfa, PDGF and others, modulate liver metabolism in health and disease, physiological and pathologic liver functions and the evolution of liver inflammation and injury to hepatic fibrosis and liver cirrhosis. Data concerning the use of a recombinant form of Interleukin-10 and Interleukin-12 in the treatment of chronic liver disease (chronic viral hepatitis, fibrosis, cirrhosis, alcoholic liver disease) and cell-mediated immunity regulation are widely discussed in the review.

Cytokines↗
PubMed2000

[Sodium in clinics and complications of liver cirrhosis].

The changes in sodium homeostasis most frequently are expression of water-electrolyte balance disturbances in patients with liver cirrhosis. Hyponatremia of water excess is found in 35% of the patients with cirrhosis and ascites. This disturbance is most frequently connected with raised antidiuretic hormone (vasopressin) secretion and is realized by including of nonosmotic stimulating mechanisms. The vasopressin plays a leading role in pathogenesis of disturbed water metabolism in the liver cirrhosis. Some patients with hepatorenal syndrome are established with highest plasma vasopressin concentrations. Gene expression of the regulation of kidney vasopressin-sensitive water channels (aquaporin-2 proteins) is also raised in the liver cirrhosis. Using in practice vasopressin-type 2 (V-2) receptor antagonists gives hopeful results in medical treatment of water-electrolyte disturbances in patients with advanced liver cirrhosis.

Gene Expression↗
PubMed1999

A comparative analysis of the postoperative complications of thyroid cancer surgery related to surgical approach.

A retrospective study of the postoperative complications in 129 patients treated for thyroid cancer in the clinics of surgery of the Higher Medical Institute for a period of 9 years (1988-1996) was performed. The majority of the patients (90) were treated by total thyroidectomy. Subtotal thyroidectomy was performed in 21 and thyroid lobectomy in 15 patients. Postoperative complications occurred in 56 of the operated patients. Of these 5 had permanent and 51 transient complications. Most of the complications (80.35 +/- 3.56%) ensued from total thyroidectomy. The variety of the complications included permanent hypoparathyroidism in 3 patients, transient hypocalcemia in 37 patients, injury of the recurrent laryngeal nerves in 11 patients, esophageal damage in 1 patient, hematoma within the operation field in 1 patient and suppuration of the operative wound in 1 patient. Four of the patients with injury of the recurrent laryngeal nerve suffered from obstruction of the airways which required temporary tracheostoma to be performed. No lethal postoperative outcome was observed. The data of the study are discussed in relation with the literature data.

Humans↗
PubMed1999

[The extrahepatic manifestations in hepatitis C virus (HCV) infection].

The hepatitis C virus (HCV) infection could affect not only the liver, but also other tissues, organs and systems. The number of the reported in the literature extrahepatic lesions by HCV incessantly increases. A reliable association between the infections by HCV and the mixed cryoglobulinaemias, membrano-proliferative glomerulonephritis and porphyria cutanea tarda is confirmed. The participation of HCV in the pathogenesis of some diseases of the thyroid gland, the lymphocytic sialadenitis, lichen planus, diabetes mellitus, thrombocytopenia, antiphospholipid syndrome, etc., is assumed. The extrahepatic lesions by HCV are probably connected with the participation of the immune system, but they may be as well due to the replicating virus in the affected tissues, organs and systems. The pathogenetic mechanisms of the extrahepatic and autoimmune manifestations of the infection with HCV are not elucidated, which poses difficult therapeutic problems regarding the choice of interferon and/or corticosteroid hormones.

Cryoglobulinemia↗
PubMed1999

[The systemic and local immune responses in patients with alcoholic liver cirrhosis depending on hepatitis C viral infection (HCV)].

The systemic and local immune response was studied in patients with alcoholic liver cirrhosis and the significance of the combined infection with HCV. To investigation were submitted 23 patients (16 males and 7 females) aged between 29 and 61 years with alcoholic liver cirrhosis. Of them 14 were anti-HCV(+) and 9 anti-HCV(-). As controls were used 36 clinically healthy individuals, matched by sex and age to the patients. The flow cytometric analysis of the lymphocyte (Ly) populations from the peripheral venous blood and of cells from liver aspirate obtained by blind liver biopsy according to Menghini, was performed with FacsTAR (Becton Dickinson). In the anti-HCV(-) patients, as compared to the controls (patients/controls) the Ly subpopulations were increased: CD3+/mm3:2010 +/- 738/1440 +/- 388; CD4+/mm3:1350 +/- 441/991 +/- 442; IL-2R+/mm3:133 +/- 78.5/31 +/- 20. In the anti-HVC(+) patients we established increased IL-2R+/mm3: 170 +/- 126 as compared with the controls and anti-HCV(-) patients. The suppressor/cytotoxic (CD8+) Ly with their suppressor (CD8+CD11b+) and cytotoxic (CD8+CD11b-) subpopulations and natural killers (CD16+) had a tendency to diminution in the anti-HCV(+) patients. In both examined groups the B (CD19+) Ly were non-significantly increased. The flow cytometric analysis of the cells from the liver specimen in 9 patients of whom 3 anti-HCV(-) and 6 anti-HCV(+) revealed that CD3+ on the average were 32.8% +/- 20.4% (from 9.2% to 65.1%); CD4+ were 21.1% +/- 7.4% (from 12.0% to 34.5%); CD8+ 22.6% +/- 11.8% (from 4.7% to 39.8%) and their values were higher in the anti-HCV(+) patients; the correlation CD4+/CD8+ = 1/1.09 +/- 0.6; CD16+ were 12.9% +/- 10.1% (from 1.9% to 34.8%); CD19+ varied from 3.2% to 27.8%; monocytes (CD14+) were 7.69% +/- 5.65 (from 2.0% to 15.8%) from the cells of the aspirate and their percentage contents was higher in the anti-HCV(+) patients. The results of out study revealed that in patients with alcoholic liver cirrhosis changes in the cell immune response were also observed and that they were more marked in infection with HCV.

Adult↗
PubMed1999

[The immunological changes and prognosis of cholestatic jaundice in choledocholithiasis].

Fifty-six patients presenting choledocholithiasis are covered by the study. They are distributed in groups according to total serum bilirubin values, as follows: with total serum bilirubin < 20 mumol/l--17; 20 to 50 mumol/l--13; 50 to 80 mumol/l--9; and > 80 mumol/l--17 cases. Sixty healthy, sex and age matched individuals serve as controls. The immunocompetent cells are determined flow cytometrically with FACS TAR (BECTON DICKINSON). A panel of monoclonal antibodies (Becton Dickinson) is used, including: Leu4 (anti-CD3+)--T-lymphocytes; Leu3a (anti-CD4+)--helper/inducer lymphocytes; Leu2a (anti-CD8+)--suppressor/cytotoxic cells; Leu11a (anti-CD16+)--cells with a natural killer activity; Leu12 (anti-CD19+)--B-lymphocytes. As shown by the obtained results there are no changes in cell-mediated immune response among choledocholithiasis patients with normal values of total serum bilirubin. Parallel to increasing the degree of cholestatic jaundice (ChJ) severity, the absolute values of lymphocytes and their subpopulations decrease. The deficit is most clearcut in patients presenting the highest degree cholestasis, as compared to healthy individuals ((Ly: 1690 +/- 174/2277 +/- 186; CD3+: 956 +/- 119/1793 +/- 67; CD4+: 607 +/- 83/988 +/- 80; CD8+: 239 +/- 52/639 +/- 85; CD16+: 146 +/- 38/367 +/- 55; CD19+: 181 +/- 33/200 +/- 13. In 11 cases with early restored biliary drainage (by the 21st day of ChJ), total serum bilirubin decreases within 10 days after the operation (choledochoduodenoanastomosis), whereas lymphocytes and their subpopulations show an increase in absolute values. Two months after choledochoduodenoanastomosis, the total serum bilirubin and the lymphocyte subpopulations being examined regain their normal values. In two instances with rather late biliary drainage recovery (30 days after ChJ) the total serum bilirubin and lymphocyte subpopulations under study show no tendency whatsoever towards normalization at 10 days postoperatively. The results of the study demonstrate that the poor prognosis among ChJ patients is also related to inhibition of the cell-mediated immune response. The early biliary drainage recovery (at 21 days of ChJ) exerts a more favourable effect on the immune system, and improves the prognosis of the clinical course run by the pathological process.

Aged↗
PubMed1998

Meta-analysis methodology for combining non-parametric sibpair linkage results: genetic homogeneity and identical markers.

Meta-analysis methodology is developed for combining sibpair linkage results across multiple studies employing different study designs, some employing quantitative traits (e.g., blood pressure) and some employing qualitative traits (e.g., clinical hypertension), under the assumption that the underlying (disease) trait loci are the same. Pooling results based on three commonly used sibpair methods is considered: the affected sibpair method for dichotomous traits and, for quantitative traits, the Haseman-Elston regression method and the Risch-Zhang extremely discordant sibpair method. The proportion of genes shared identical by descent (IBD) by a sibpair of certain trait outcomes is chosen as a common effect to be pooled across studies. Variation in the observed IBD proportions among individual studies is modeled using a random effects model. A heterogeneity test is provided to assess the variability among individual studies. When results from all three types of studies are available, we derive pooled estimates of IBD proportions both for sibpairs with extremely concordant trait values and for sibpairs with extremely discordant trait values, and construct a combined test of linkage based on the difference of the two estimates. Simulation studies demonstrate the need for and the advantage of meta-analysis of linkage results. We also present some guidelines for reporting linkage studies bearing potential future meta-analysis in mind.

Chromosome Mapping↗
PubMed1997

Convection versus conduction cooling for induction of mild hypothermia during neurovascular procedures in adults.

Hypothermia for cerebral protection is usually achieved by administration of intravenous fluids at room temperature, cooling ambient air, ice packs, and a temperature-adjustable circulating water mattress. We compared cooling by conduction by using a water mattress to cool by convection by using a forced-air cooling device. Twenty patients were prospectively randomized to two groups: 10 patients cooled by convection (CC) and 10 patients cooled by traditional methods (TC). Two patients in the CC group were withdrawn from the study and excluded from the analysis; one patient for failure to cool despite the use of both techniques, and the other for the abrupt onset of arrhythmias and myocardial depression during hypothermia. Temperature was measured at the tympanic membrane, pulmonary artery, and esophageal probe sites and recorded every 15 min. The time required to reach the target temperature range of 33-34 degrees C was recorded. We found no differences in the temperatures measured at the three sites during cooling and rewarming. Baseline temperatures recorded from the pulmonary artery catheter before beginning "active cooling" were similar in both groups (TC, 35.0 +/- 0.2 degrees C vs. CC, 35.3 +/- 0.1 degrees C). We found no difference in the time to target temperature between TC and CC (TC, 178 +/- 25 min vs. CC, 142 +/- 21 min). One patient had some arrhythmias on cooling in the convective group, but her preoperative condition may have been responsible. In conclusion, cooling by convection appears to be a safe alternative to conduction cooling.

Adult↗
PubMed1996

Combining extremely concordant sibpairs with extremely discordant sibpairs provides a cost effective way to linkage analysis of quantitative trait loci.

Extremely discordant (ED) sibpairs have been shown to be very powerful for linkage analysis of human quantitative traits [Risch and Zhang (1995) Science 268: 1584-1589]. In many cases, the extremely concordant (EC) sibpairs collected in the process of screening for ED sibpairs carry valuable information for linkage. Therefore, it seems justifiable to investigate the advantages of genotyping and to include them with the ED sibpairs for linkage analysis. Herein we explore the distributions of EC as well as ED sibpairs under various genetic models and provide a basis for combining both types of sibpairs. A simple statistic testing means of genes shared identical by descent (IBD) in applied to combine both types of EC sibpairs (high-high and low-low) with the ED pairs. We show that when a decent number of EC pairs is added to the ED sample for analysis, the power is much enhanced, making it especially desirable when the number of available ED pairs is small. We show at the same time that combining EC pairs with ED pairs is more cost effective than pursuing ED sibpairs alone.

Costs and Cost Analysis↗