Theory of the Supercurrent Diode Effect in Rashba Superconductors with Arbitrary Disorder

We calculate the nonreciprocal critical current and quantify the supercurrent diode effect in two-dimensional Rashba superconductors with arbitrary disorder, using the quasiclassical Eilenberger equation. The nonreciprocity is caused by the helical superconducting state, which appears when both inversion and time-reversal symmetries are broken. In the absence of disorder, we find a very strong diode effect, with the nonreciprocity exceeding 40% at optimal temperatures, magnetic fields, and spin-orbit coupling. We establish that the effect persists even in the presence of strong disorder. We show that the sign of the diode effect changes as magnetic field and disorder are increased, reflecting the changes in the nature of the helical state.

Different pathways involved in the stimulatory effects of homocysteine on rat duodenal smooth muscle

Recent studies have confirmed that hyperhomocysteinemia is associated with gastrointestinal diseases; however, the direct effect of homocysteine on gastrointestinal reactivity still remains unknown. The aim of this study was to demonstrate how homocysteine may affect nitric oxide mediated duodenal relaxation and whether cholinergic receptors and K+ channels take part in stimulating motility, as well as to explore whether oxidative stress is associated with homocysteine-mediated effects. Experiments were carried out on male rats, body mass 250-300 g. Two groups of animals were treated by i.p. application of saline and D,L-Hcy (0.6 μmol/g bm). After 2h of incubation, the duodenal segments were prepared for biochemical analysis and contractile response measurements in an organ bath with Tyrode’s solution. Effects of TEA (10 mmol/L) and L-NAME (30 μmol/L) on duodenal contractility in the presence of D,L-Hcy (0.6 μmol/g bm) were investigated. Elevated homocysteine levels seem to be of crucial importance for the deterioration of contractility through nitric oxide mediated relaxation, and, in part, by activation of K+ channels. Hcy showed direct promuscarinic effects, since 30 min pretreatment of rat duodenum significantly enhanced the contractile effect of increasing concentrations of ACh (10−9-10−2 mol/L). Catalase activity, superoxide dismutase, glutathione peroxidase and the total antioxidant system were reduced while the thiobarbituric acid-reactive substances level was elevated. Our data showed a consistent profile of gastrointestinal injury elicited by sulfur-containing amino acid-homocysteine. This could contribute to explain, at least in part, the mechanisms involved in human gastrointestinal diseases associated to hyperhomocysteinemia.

Effects of Acute Administration of D,L-Homocysteine Thiolactone on the Antioxidative Status of Rat Intestine and Liver

Oxidative stress appears to play a role in the pathogenesis of several inflammatory gastrointestinal diseases. Increased homocysteine levels may play a role in the pathogenesis of Chron’s disease and ulcerative colitis. The aim of this study was to examine the influence of homocysteine on the antioxidant status of rat intestine and liver. The levels of thiobarbituric acid reactive substances (TBARS), activity of catalase (CAT) and total antioxidant status (TAS) were investigated in the isolated gut and liver of young male rats in the control group (8 rats) and after 3-hоur incubation in high doses of D, L-homocysteine thionolactone (Hcy) (10 μmol/L) (8 rats). Samples of duodenum, ileum, colon and liver were homogenized in sodium phosphate buffer (1:10). Homogenates were centrifuged at 10000 for 10 min at 4° C and the supernatant was taken for biochemical assays. Our results showed that high D, L-homocysteine thionolactone concentration reduced enzymatic catalase activity in homogenates of the isolated segments of duodenum (27.04%) p<0.01; ileum (37.27%), colon (34.17%) and liver (67.46%) p<0.001. Exposition to high D,L-homocysteine thiolactone concentration significantly increased TBARS levels in the duodenum (106.05%), ileum (47.24%), colon (112.75%) and liver (32.07%) (p<0.01). Homocysteine also modifi ed the total antioxidant status of homogenates from the duodenum, ileum, colon and liver, increasing by 20.68% (duodenum), 24.74% (ileum), 14.88% (colon) and 19.35% (liver) (p<0.001). Homocysteine induced a consistent oxidative stress in rat’s intestine and liver (reduced activity of catalase and increased level of TBARS), but the elevated activity of TAS in our experiments could be explained as an adaptive response to the generated free radicals which indicates the failure of the total antioxidant defense mechanism to protect the tissues from damage caused by homocysteine.

Cigarette Smoking Has no Impact on the Effect of Radioiodine Therapy in Patients with Graves Disease / Pušenje cigareta nema uticaj na ishod radiojodne terapije kod bolesnika sa Grejvsovom bolešću

Presently, there is very little data on the impact of nicotine and other components of tobacco smoking on the outcome of radioiodine therapy (RIT) in Graves’ disease (GD). Thus, this study was aimed to analyze a possible impact of cigarette smoking on the effect of radioiodine therapy in the patients with Graves’ disease.

The study included 31 patients (16 smokers and 15 non-smokers) with GD, aged from 22 to 73 years, who were treated with a single dose of iodine-131 sodium iodide (131I-NaI) and subjected to a 12-month follow-up, thereafter. Patients were treated with antithyroid drugs (ATDs) before RIT and described very intense stressful events occurring prior to diagnosing Graves’ hyperthyroidism. A successful response to RIT was defined as euthyroidism and subclinical or clinical hypothyroidism, while an unsuccessful response was defined as persistent hyperthyroidism.

Comparison of age (47.4±9.41 vs. 49.5±13.8 years, p=0.628) at the time of RIT, applied activity of 131I-NaI (372±78.4 vs. 363±43.7 MBq, p=0.675), and duration of ATDs therapy (3.47±3.33 vs. 4.94±5.62 years, p=0.387) between smokers and non-smokers showed no significant difference. The cumulative incidence of successful response to therapy in smokers and non-smokers was 31.2 vs. 46.7% (p<0.05), 50.0 vs. 60.0% (p>0.05), 56.2 vs. 60.0% (p>0.05), and 56.2 vs. 66.7% (p>0.05) after 3, 6, 9 and 12 months, respectively.

The results showed that cigarette smoking has no impact on the effect of radioiodine therapy after twelve-month period in patients who had experienced stressful events before the occurrence of Graves’ disease. However, patients with smoking habits achieved successful response later than non-smokers.

The influence of Ki-67 proliferation index on Tc-99m-EDDA-HYNIC-TOC somatostatin receptor scintigraphy in patients with carcinoids

The aim of this paper is to determine the influence of Ki-67 proliferation index on somatostatin receptor scintigraphy (SSRS) with Tc-99m-EDDA-HYNIC-TOC (Tc-99m-Tektrotyd) somatostatin analogue in patients with carcinoid tumors. Sixty-one patients (31 female, 30 male; age range: 33-76 years) were examined: 13 patients highly suspected of having a carcinoid, and 48 patients who had undergone the surgical removal of the tumor. Whole body SSRS at 4 h postinjection, spot scintigrams and SPECT of the selected regions were obtained for all patients. Tc-99m-Tektrotyd scintigraphy was classified as true positive in 26 out of 30 and true negative in 24 out of 28 patients. The sensitivity of Tc-99mTc-Tektrotyd scintigraphy was found to be as high as 94.74% in the group of patients with low mitotic index Ki67 (<2%), and it progressively decreased in patients with higher mitotic index (77.78% for Ki67 2-15% and 20% for Ki67% >20%). The likelihood of Tc-99m-Tektrotyd scan being positive when a carcinoid is present was found to be inversely proportional to the value of Ki67 proliferation index. The results showed that Tc-99m-Tektrotyd SSRS is a sensitive method for diagnosing and staging patients with well-differentiated carcinoid tumors. However, in poorly differentiated tumors with high Ki67 proliferation index, additional analyses are necessary for precise staging.

Biomarkers of acute kidney injury in pediatric cardiac surgery

OBJECTIVES

Acute kidney injury (AKI) is a significant problem in children undergoing cardiopulmonary bypass (CPB). The aims of this study were to assess the diagnostic validity of serum CysC (sCysC), serum neutrophil gelatinase lipocalin (sNGAL), urine neutrophil gelatinase lipocalin (uNGAL), urine kidney injury molecule (uKIM)-1, and urine liver fatty acid-binding protein (uL-FABP) to predict AKI presence and severity in children undergoing CPB.

DESIGN AND METHODS

We performed a prospective single-center evaluation of sCysC, sNGAL, uNGAL, uKIM-1 and uL-FABP at 0, 2, 6, 24 and 48 h postoperatively in children undergoing CPB during cardiac surgery. AKI was defined as ≥25% decrease in the estimated creatinine clearance (eCCl) from pre-operative baseline at 48h after surgery.

RESULTS

Of the 112 patients, 18 patients (16.1%) developed AKI; four of them needed acute dialysis treatment and three AKI patients died. In the AKI compared to the non-AKI group, sCysC at 2h, and uNGAL and uL-FABP at 2-48 h were significantly increased, as well as CPB, aortic cross clamp time and length of hospital stay. Biomarkers increased with worsening AKI severity. At 2h after CPB the best accuracy for diagnosis of AKI had uL-FABP and sCysC with area under the receiver operator curve (AUC) of 0.89 and 0.73, respectively. At 6 and 24h after CPB the best AUC was found for uL-FABP (0.75 and 0.87 respectively) and for uNGAL (0.70 and 0.93, respectively).

CONCLUSIONS

sCysC, uNGAL and uL-FABP are reliable early predictors for AKI after CPB. By allowing earlier timing of injury and earlier intervention, they could improve AKI outcome.

Differential expression of KCNQ1 K+ channel in tubular cells of frog kidney

The aim of this study was to evaluate KCNQ1 K⁺ channel expression in the frog kidney of Rana esculenta. KCNQ1 K⁺ channel, also known as KvLQT1, is the pore forming α-subunit of the I_Ks K⁺ channel, a delayed rectifier voltage-gated K⁺ channel, which has an important role in water and salt transport in the kidney and gastrointestinal tract. The expression of KCNQ1 K⁺ channel along tubular epithelium differs from species to species. In the present study the expression of KCNQ1 K⁺ channel in the frog kidney has been demonstrated by immunohistochemistry. The presence of KCNQ1 K⁺ channel was demonstrated in the epithelial cells of distal convoluted tubule and collecting duct. However, the pattern of expression of KCNQ1 K⁺ channel differs between distal convoluted tubules and collecting duct. All epithelial cells of distal convoluted tubules revealed basolateral expression of KCNQ1 K⁺ channel. On the contrary, only the single cells of collecting duct, probably intercalated cells, showed diffuse cell surface staining with antibodies against KCNQ1 K⁺ channel. These findings suggest that KCNQ1 K⁺ channel has cell-specific roles in renal potassium ion transport.

Thyroid blood flow and uptake of technetium-99m pertechnetate in Graves' disease

The aim of this study was to assess the relation of early thyroid blood flow (EBF) and technetium-99m pertechnetate ((99m)TcO(-)(4)) uptake, as an early diagnostic index in patients with Graves' disease (GD) by dynamic thyroid scintigraphy (40 frames, 3 sec/frame). Thirty patients with GD with mean age 50.0 +/- 9.0 y, range: 35.0-69.0 y, were studied. The results obtained were compared with those of 30 euthyroid individuals (EI) of mean age 46.9 +/- 12.5 y, range: 22.0-68.0 y. The parameters of (99m)TcO(-)(4) EBF and early uptake studied, derived from the background subtracted time activity curves, were as follows: a) The duration of the EBF in sec; b) The perfusion index (PI) - the ratio of counts at the beginning and at the end of the EBF; c) The uptake index 1 (UI1)- the counts ratio between the counts at the end of the EBF and at the 2nd min d) The uptake index 2 (UI2) - the counts ratio between the 1st min and the 2nd min of the uptake curve and e) Delayed (99m)TcO(-)(4) thyroid uptake (TcTU) at 20 min was also calculated as a percentage of net counts activity accumulated in the thyroid gland at 20 min. Results were as follows: a) The mean values of the duration of the EBF were shorter in GD patients (9.90 +/- 2.94 sec) than in EI (15.70 +/- 4.01 sec; P<0.0001); b) PI did not differ significantly (P>0.05); c) The mean UI1 and UI2 values of thyroid uptake of 99m TcO4- were significantly lower in GD (UI1=0.621, UI2=0.772) as compared to EI (UI1=1.106, UI2=0.947; P<0.0001 for both) and d) TcTU values were significantly higher in GD (13.6%) than in the group of EI (1.29%; P<0.0001). A good correlation was found in patients with GD between early (UI1 and UI2) and delayed TcTU (r = -0.562; P=0.010 and r = -0.459; P=0.042 respectively). Also, in patients with GD the EBF correlated poorly with UI1, UI2 and TcTU (P>0.05 for all these parameters). In conclusion, the results of this study indicate that the duration of EBF did not relate significantly to the height of TcTU values in patients with GD. On the contrary, the early uptake, indices UI1 and especially UI2 were shown to be faster in the majority of GD patients and correlated well with the TcTU. These parameters may be used as diagnostic indices for GD. Further investigation is required to support the above findings.

Solitary fibrous tumors of the pleura

Two cases of female patients with solitary fibrous tumor of the pleura are described. Chest radiography and computed tomography showed the presence of a giant mass with inhomogeneous density in the hemithorax in both cases. Transthoracic needle biopsy of the masses showed benign fibrous tissue. Both patients underwent thoracotomy. The tumors arose from the visceral pleura, were peduncular, appeared well-circumscribed with exterior surface smooth, firm and multinodular. The size of tumors were 16x11x6 cm and 15x11x4.5 cm, weighed 650 g and 573 g and both were successfully resected. The pathological diagnosis was benign solitary fibrous tumor of the pleura. Seven years after the operations the clinical condition and chest radiography are normal in both women.

Diuresis renal scintigraphy "F-0" in diagnosing of upper urinary tract obstruction in children: the clinical significance

BACKGROUND

The aim of this study was to assess the clinical relevance of diuresis renal scintigraphy after simultaneously administered radiopharmaceutical and diuretic (DRS "F-0") in diagnosing obstruction of upper urinary tract in children with previously documented hydronephrosis and ureterohydronephrosis, analyzing the value of qualitative and quantitative scintigraphy parameters.

MATERIAL AND METHODS

This retrospective study enrolled 82 children (30 girls and 52 boys aged between 2 months and 16 years; mean 5.8 +/- 4.5 years) with previously documented hydronephrosis or ureterohydronephrosis (42 left-sided, 28 right-sided and 12 bilateral). DRS "F-0" was started after intravenous administration of diethylene-triamine- pentaacetic acid (DTPA) mixed with furosemide. Results of DRS "F-0" were analyzed qualitatively (visual analysis of scintigrams and renography curves) and quantitatively (time to reach maximum of the kidney curve-T max, washout of the tracer-WO, the furosemide clearance half-time (F/2) and individual kidney function - IKF) and compared with the final diagnoses obtained in 37 children (42 nephroureteric units - NU) after surgery, in 41 children (48 NU) during the medical follow-up lasting at least 6 months, and in 4 children (4 NU) using invasive diagnostic procedures. Diagnostic criteria for obstructed NU (kidney with corresponding ureter) considered presence of pathological at least two of five scintigraphy variables characterized as a sign of obstruction.

RESULTS

Forty true positive and 37 true negative results were detected using diagnostic criteria for obstructed and normal NU by means of DRS "F-0". DRS "F-0" failed to detect obstruction in 5 children with a total of 6 obstructed NU, while the results were marked as false positive in 9 children (11 NU). Qualitative scintigraphy analysis was found to be the most sensitive (91%) and accurate predictor (85%) in differentiating obstruction from non-obstructive renal unit. High sensitivity in predicting obstruction was also found for both washout of the radiopharmaceutical (87%) and for furosemide clearance half time (85%). Overall sensitivity of DRS "F-0" using proposed diagnostic criteria in differentiating obstruction was 87%, specificity 77% and accuracy 82%. However, DRS "F-0" has been shown to be more sensitive (90%) in children with UPJ and UVJ obstruction concerning children in whom obstruction was caused by other urinary tract diseases.

CONCLUSION

This study showed DRS "F-0" as a sensitive and reliable method in diagnosing children with obstructions of the upper urinary tract. The great advantage of the protocol DRS "F-0" over other diuresis renography protocol modalities is due to the shorter time of the acquisition by half, and the avoidance of additional diuretic application. However, conventional quantitation of diuresis renogram did not improve the sensitivity and specificity with respect to the qualitative analysis of scintigrams and renography curves.

[Results of treatment of cyanotic heart defects in children]

Cyanotic heart diseases are relatively rare, but they are severe and heterogeneous congenital heart diseases, which require complex surgery. Development of different advanced surgical procedures, such as arterial switch operation (ASO), Fontan and its modifications, Norwood etc. operations, as well as better perioperative care significantly improved survival rate and quality of life of these children. The study group included 308 children treated for cyanotic heart disease in Yugoslavia, in the period January 2000 to July 2004. Some of them (239, 77.6%) were treated at the University Children's Hospital in Belgrade, and others (69, 22.4%) in different institutions abroad. The age of the operated patients varied between 1 day and 19 years (median 12 months). The patients (pts) were divided into four groups, according to the disease and type of the operation. In the whole group of 308 patients treated due to cyanotic heart disease, there were 232 (75.3%) cases with open heart surgery and 76 (24.7%) with closed procedures. The mortality rate was significantly different between disease/operation groups, and age groups. Average mortality rates differed from 11.8% for palliative procedures to 12.5% for complete corrections. Mortality rate and achieved surgical results in treatment of children with cyanotic heart diseases were significantly worse than those published by leading cardiac surgery centers in the world. However, there is a clear tendency in introducing new surgical procedures, lowering the age at which the operation is done and decreasing the mortality rates.

[Cytohistologic and immunohistochemical characteristics of the aortic intima and media in coarctation of the aorta of the adult type]

INTRODUCTION

Classically, coarctation of the aorta has been divided into infantile and adult forms. The vascular malformation responsible for coarctation is a defect of the vessel intima and media giving rise to a prominent posterior infolding ("the posterior shelf") which, in some cases, may extend around the entire circumference of the aorta. Histological examination of the coarcted aortic segment discloses intimal and medial lesion consisting of thickened ridges that protrude posteriorly into the aortic lumen. Intimal proliferation and disruption of elastic tissue may occur in adult type.

OBJECTIVE

The smooth muscle cells phenotype in the aortic intimal thickening, presence of inflammatory cells and contents of the intimal and medial pseudocysts were investigated.

MATERIAL AND METHODS

The samples of coarctation segments excised at surgery from 10 patients aged from 2 to 13 years were examined. For light microscopy, the specimens were dehydrated in graded ethanol (70-100%), cleared in xylol and embedded in paraffin. Sections of 5 microm thick were cut on Leica SM 2000R and Leica Reinhart Austria microtome and stained with orcein and Alcian blue-PAS at pH 1.0 and pH 2.5. Immunocytochemical staining was performed on 5 microm sections from formaldehyde-fixed paraffin-embedded blocks, using a labeled streptavidin-biotin method with an LSAB kit (Dako). Sections were deparaffinized and rehydrated. After microwave treatment of 21 minutes in citrate buffer pH 6.0, endogenous peroxidase activity was blocked with 3% H2O2 for 15 minutes. The sections were first incubated with the primary antibody for 60 minutes (alpha-smooth muscle actin-alpha-SMA, vimentin, desmin, myosin haevy chains-MHC, CD3, CD45, S-100 and Proliferating Cell Nuclear Antigen-PCNA), then with biotinylated link antibody and finally with peroxidase-labeled streptavidin. Slides were counter-stained with hematoxylin, washed in water and mounted. For electron microscopy, the primary fixative consisted of 2.5% glutaraldehyde in 0.1 M sodium cacodylate-HCl buffer (pH 7.4) for 24 h at 4 degrees C. The specimens were postfixed for 1 h at 4 degrees C in 1% osmium tetroxide in 0.1 M cacodylate buffer and 4.8% uranyl acetate for 24 h at 4 degrees C. The samples were dehydrated in graded ethanol (70-100%) and embedded in Epon 812. The samples were cut with a diamond knife on an LKB Ultratome. Ultra-thin sections were stained with 2% uranyl acetate and alkaline lead citrate.

RESULTS

All samples had focal intimal thickening on the posterior aortic wall, with accumulation of mucins which were stained with Alcian blue-PAS on pH 1.0, followed by prominent hypocellularity. Rare smooth muscle cells (SMC) showed immunoreactivity on alpha-SMA and vimentin, but not on desmin, MHC or CD3 and CD45. A large number of cells in apoptosis was noticed in the inner media on the posterior wall. On the anteromedial wall, a large number of PCNA- and S-100- positive cells was noted in the inner media while one layer of MHC- and desmin-positive cells was noted in the outer media. The elastic lamellae were focally disrupted by pools which were stained with Alcian blue-PAS at pH 1.0.

DISCUSSION

In all examined samples, the immunocytochemical and TEM results revealed the presence of dedifferentiated smooth muscle cells which express alpha-SMA and vimentin, with a lack of expression of desmin and MHC. Results of this study also showed the reduction of cell number in the intima and media, followed by apoptotic smooth muscle cells in the inner media of the posterior wall and the absence of inflammatory cells. Such finding suggests that apoptosis but not necrosis may be the mechanism of reduction of cell number. The presence of smooth muscle cell proliferation in the inner media of the anteromedial wall and one layer of differentiated SMC in the outer part may lead us to suppose that changes of media (including dedifferentiation of the cells and disruption of elastic tissue) appear from inner to outer part and from posterior to anteromedial wall. The presence of pseudocysts which are stained with Alcian blue-PAS at pH 1.0 show large amount of mucins in elastic fibers.

CONCLUSION

The intimal thickening on the posterior aortic wall is composed of small number of dedifferentiated smooth muscle cells (SMC). Some of these cells are in apoptosis. On the anteromedial wall, the intima and media are composed of proliferated SMC and small number of SMC which exhibit contractile phenotype. In all parts of the aortic wall, there is a large number of pseudocysts with large amount of mucins, without presence of inflammatory cells.

[Surgery for coarctation of the aorta in infants younger than three months]

INTRODUCTION

Recurrent coarctation is a complication which is seen at a consistent rate following repair for coarctation of the aorta in young infants.

OBJECTIVE

This retrospective analysis was carried out to compare the results between resection with end-to-end anastomosis (ETE), and resection with extended end-to-end anastomosis (E-ETE), in this age group during late follow-up period. The role of ductus arteriosus is not clearly defined and the second objective of this study was to analyze intimal thickening in aortic coarctation.

MATERIAL AND METHODS

From 1999 to 2003, 45 patients less than 3 months of age underwent repair of aortic coarctation. Mean age was 24 days (2-89 days), average weight was 3.5 +/- 0.6 kg (2.4-5.2 kg). The method of repair was ETE in 14 (31.1%) patients, E-ETE in 29 (64.4%) patients and other techniques were applied in 2 cases. Demographic, morphometric, clinical and operative variables were analyzed for correlation with recurrent arch obstruction. In order to characterize the components of intimal thickening in coarctation, narrowed segments of aorta resected from 16 neonates during surgery were examined immunocytochemically and by electron microscopy. For light microscopy, the specimens were dehydrated in graded ethanol (70-100%), cleared in xylol and embedded in paraffin. Immunocytochemical staining was performed in 5 microm sections from formaldehyde-fixed paraffin-embedded blocks, using a labeled streptavidin-biotin method with an LSAB kit (Dako).

RESULTS

Early mortality was 6.7% (CI 95%, 2.9%-10.4%). All early deaths (3 patients) occurred in infants with associated ventricular septal defects (p<0.05). The mean follow-up for all patients was 30 +/- 21 months (range 1.5-63 months). During mean follow-up of 2 months, recurrent arch obstruction was diagnosed in 9 patients (21.4%). Two patients with associated complex heart defects died before re-intervention, one had mild gradient on catheterization (20 mm Hg) and one is waiting for catheterization. Five patients were reoperated and the mean time to re-intervention was 4 months (range 2.6-6 months). Kaplan-Meier freedom from recoarctation was 78.1 +/- 6.4% at 5 years in the whole group. Freedom from recoarctation was 60.6 +/- 15.4% at 25 months in ETE group and 86.2 +/- 6.4% at 60 months in E-ETE group (p=0.062). Factors associated with recoarctation, obtained by univariable Cox regression, included abnormal right subclavian artery (p=0.003), hypoplastic proximal transverse aortic arch (Z < or = -2, p=0.025) and weight at operation < or = 3 kg (p=0.02). Abnormal origin of the right subclavian artery was the only independent predictor of recoarctation obtained by multivariable Cox regression analysis.

DISCUSSION

All examined specimens had intimal thickening of the posterior aortic wall, with accumulation of smooth muscle cells (SMC) with alpha smooth muscle actin (alpha-SMA) and vimentin-immunoreactivity (but not desmin and MHC) and also expressed PCNA and S-100. In the inner media of the anteromedial wall of the aorta, all specimens had large number of SMC expressing desmin and MHC. SMC in the inner media exhibit contractile phenotype and their origin could be ductal.

CONCLUSION

Both procedures are effective for coarctation repair in young infants. Risk of recoarctation is a function of the complex anatomy of the arch, while residual ductal tissue may play a significant role.

[Biomechanical characteristics of spinal cord tissue--basis for the development of modifications of the DREZ (dorsal root entry zone) operation]

Mechanical properties of the spinal cord tissue--biological basis for the development of the modality of the DREZ surgery lesioning technique Succesful treatment of the chronic neurogenic pain of spinal cord and cauda equina injury origin remains a significant management problem. The mechanism of this pain phenomenon has been shown to be related to neurochemical changes that lead to the state of hypereactivity of the second order dorsal horn neurons. The DREZ surgery (Dorsal Root Entry Zone lesion), designed to destroy anatomy structures involved in pain generating thus interrupting the neurogenic pain mechanism, as a causative procedure in treating this chronic pain, has been performed by using different technical modalities: Radiofrequency (RF) coagulation technic, Laser, Ultrasound and Microsurgical DREZotomy technic. The purpose of the study was to assess the possibility for the establishment of the lesioning technic based on the natural difference in the mechanical properties between the white and gray cord substance. We experimentally deteminated mechanical properties of the human cadaveric cord white versus gray tissue for the purpose of testing possibility of selective suction of the dorsal horn gray substance as a DREZ lesioning procedure. Based on the fact of the difference in tissue elasticity between white and gray cord substance we established a new and simple DREZ surgical lesioning technique that was tested on cadaver cord. For the purpose of testing and comparing the size and shape of the DREZ lesion axchieved the DREZ surgery has been performed on cadaver cord by employing selective dorsal horn suction as a lesioning method. After the procedure cadaver cord underwent histological fixation and analysis of the DREZ lesions achieved. Our result revealed that the white cord substance with longitudinal fiber structure had four time higher dynamical viscosity than gray substance of local neuronal network structure (150 PaS versus 37.5 PaS) that provided possibility for the safe and selective suction of the gray substance of the dorsal horn. Technic includes incision of the dorsolateral sulcus according to Sindous Microsurgical DREZotomy technic than suction under visual control of the dorsal horn gray matter using succer adopted from the lumbar puncture nidle. Operative experimental testing and hystological analysis confirmed expected size and shape of the DREZ lesion performed by dorsal horn suction as DREZ lesioning technique. The utility, selectivity and safety of this technic has been provided by the natural mechanical properties of the cord tissue itself. Application of the Dorsal horn suction as a DREZ lesioning in humans confirmed this technic as a safe and reliable DREZ lesioning method.

Radionuclide voiding patterns in children with vesicoureteral reflux

The purpose of this study was to evaluate bladder function in children with vesicoureteral reflux (VUR) by means of indirect radionuclide cystography (IRNC), and to investigate whether IRNC can identify those children with voiding dysfunction. The study enrolled 74 neurologically intact children, 14 boys and 60 girls aged 2-14 years, with VUR documented using contrast micturating cystourethrography as the initial method. In all patients, IRNC was performed using technetium-99m diethylene triamine penta-acetate (DTPA). Based on the urodynamic findings, three groups were distinguished: a group with VUR and normal urodynamic findings ( n=27), a group with VUR and detrusor hyper-reflexia ( n=43) and a group with VUR and detrusor-sphincter dyssynergia ( n=4). A control group comprised 64 healthy children, aged 2-13 years, without any symptoms of lower urinary tract dysfunction. The dynamics of bladder emptying were studied in the posterior view after intravenous injection of 37 MBq/10 kg b.w. DTPA, with acquisition of 90 2-s frames during voiding. The parameters evaluated were: voided urine volume (VV), bladder capacity, functional bladder capacity (FBC), residual urine, voiding time, average flow rate, peak flow rate (PFR) and ejection fraction (EF). With regard to the final urodynamic diagnosis, FBC, PFR and EF were found to be significant IRNC predictor variables using the logistic regression method. If abnormality on at least two of the three significant predictor variables was taken as the criterion of voiding dysfunction, the overall sensitivity, specificity and accuracy of IRNC in the detection of voiding dysfunction were 81%, 78% and 80%, respectively. Three radionuclide voiding patterns were detected in children with VUR: (1) a normal voiding pattern characterised by normal FBC with near-normal PFR and EF values, (2) a markedly reduced FBC with significantly reduced VV, PFR and EF values (in children with bladder instability), and (3) a higher bladder volume with a near-normal value for PFR and a slightly reduced or near-normal EF (in children with detrusor-sphincter dyssynergia). This study confirmed the association between lower urinary tract dysfunction and congenital VUR. IRNC was found to be a simple, non-invasive method which allows reliable differentiation of voiding patterns in patients with VUR. IRNC can be used as a first-line method for screening in children with VUR to identify those with abnormal voiding patterns.

Alteration of 99mTc-DMSA biodistribution in glomerulonephritis

BACKGROUND

The aim of this study was to assess the relation between (99m)Tc-DMSA biodistribution and its reliability as a marker of renal function in patients with glomerular kidney diseases.

MATERIAL AND METHODS

Sixty-seven patients involved in this study were classified into two groups according to (99m)Tc-DTPA clearance and serum creatinine values: the 1st group consisted of 42 patients without renal failure while the 2nd group included 25 patients with renal failure. (99m)Tc-DMSA biodistribution was determined by measuring kidney, blood and urine activity at 2 h and 4 h.

RESULTS

The results, compared with those of 23 healthy volunteers, indicated the quantitative alteration of (99m)Tc-DMSA distribution in both glomerulonephritis patient groups. In reference to the control mean values of 2 h and 4 h, in patients without renal failure, kidney activity was found decreased to 52% and 57%, while the blood activity increase of 37% and 44% was recorded together with the urine activity increase of 38% and 23%. In patients with renal failure the alterations of renal and blood activity were more remarkable, but the urine loss was found to be unchanged.

CONCLUSIONS

It is suggested that these biodistribution changes originate mainly from tubular impairment. However, in glomerulonephritis patients, altered glomerular filtration might considerably affect biodistribution of this radiopharmaceutical and limits its suitability for precise quantitative estimation of renal function.

[Surgical treatment of rare anatomic variations and anomalies of the thyroid gland]

Choristoma and thyroid gland malpositions are embryonal disorders. The aim of this article is ten years analysis of their diagnostic and operative treatment. In 1425 thyroidectomies we have found: one lingual, intratracheal, intracardial thyroid and ovarial struma; six separated intrathoracic goitre and 10 mostly intrathoracaly (80%) situated goitre; 1.4% out of all. Correct preoperative diagnosis we have in lingual thyroid, two intrathoracal thyroid and in all mostly intrathoracal thyroids, and in others after histopathological examination. Operative approach was: collar incision with medial sternotomy in nine, collar incision with lateral thoracotomy in three, right thoracotomy in two, and only collar incision in one. There were two operative complications, one recurrent nerve lesion and one mediastinal haematoma. There was no hypocalcaemia and mortality. Thyroid gland anomalies are very rare and associated with lot of problems in diagnostic and treatment. In specialised institutions frequency of operative complications is the same like in routine thyroid gland surgery.

Kidney ectopeptidases in gentamicin and mercuric chloride-induced acute renal failure

The clinical use of gentamicin is associated by nephrotoxicity in over 10% of patients. However, the biochemical events responsible for proximal tubular injury and acute renal failure (ARF) are still unclear. In the present study, effects of gentamicin and, comparatively, of mercuric chloride upon rat kidney cortex ectopeptidases were studied. Gentamicin was given i.p., 100 mg/kg daily for up to 6 days, mercuric chloride i.p. once 2.5 mg/kg to rats studied after 3 days. Kidney cortex aminopeptidase N decreased significantly after 3 and 6 days' treatment (p < 0.01), however, angiotensinase A significantly decreased after 3 (p < 0.01), and much more after 6 days of gentamicin treatment (p < 0.001). Dipeptidylpeptidase IV activity was significantly decreased only after 6 days of treatment with gentamicin. In mercuric chloride-induced ARF all three peptidase activities were markedly decreased (p < 0.001). These results suggest that gentamicin-induced decrease in ectopeptidase activities could compromise vasoactive and other biologically active peptides handling, with important consequences upon renal function and metabolism.

Radionuclide voiding pattern in children with unstable bladder

BACKGROUND

The purpose of this study was to investigate bladder function parameters by means of quantitative radionuclide cystography (QRC) in anxious, irritable children with unstable bladder.

METHODS

Quantitative radionuclide cystography was performed in 18 children aged between 8 and 12 years, without evidence of neurologic and nephrologic disorders. Findings were compared with those obtained in 10 healthy children aged between 7 and 10 years. The dynamics of the bladder emptying were studied after intravenous injection of 37 MBq/10 kg b.w. 99mTc-diethylenetriaminepentaacetic acid (DTPA) in the posterior views. Images of 90 frames every 2 sec. were stored in the 64 x 64 computer matrix during voiding. The patients voided into a container and the volumes were measured.

RESULTS

The parameters evaluated were: functional bladder capacity (ml)--FBC, expected bladder capacity (ml)--EBC, percentage of EBC (%), voided urine volume (ml)--VV, residual urine (ml)--RU, voiding time (sec)--VT, average flow rate (ml/sec)--AFR and peak flow rate (ml/sec)--PFR. There was a statistically significant difference between controls and children with unstable bladder in the following parameters: FBC 288 +/- 33 vs. 244 +/- 27 ml (p < 0.001), % of EBC 99 +/- 6 vs. 82 +/- 6% (p < 0.0001), VV 265 +/- 37 vs. 202 +/- 35 ml (p < 0.0001), RU 22 +/- 11 vs. 48 +/- 19 ml (p < 0.007), AFR 13 +/- 5 ml/sec vs. 9 +/- 4 ml/sec. (p < 0.01) and PFR 19 +/- 2 vs. 13 +/- 3 ml/s (p < 0.0001), respectively. The VT obtained from the control group of 23 +/- 9 s did not differ significantly from the value of children with unstable bladder of 28 +/- 14 s.

CONCLUSION

The results show that quantitative radionuclide cystography is a simple, noninvasive method, which allows a good separation of patients with unstable bladder from the children with normal voiding pattern.

Fungus-like hyphochytrids associated with human disease

We report two cases, with liver and brain abscess, respectively, where fungus-like organisms belonging to the Hyphochytriomycota were found at the site of inflammation together with Peptococcus in the first and Cysticercus cellulosae in the second case. This is the first time these groups of organisms have been reported in human material. The role of hyphochytrids in human pathology remained uncertain as they were found together with already known human pathogens.

[Experimental study of the pathogenesis of frostbite. Part III. Significance of energy status of muscle tissue in the pathogenesis of frostbite]

The authors have investigated energy status of muscle tissue of the lower legs of Wistar rats subjected to freezing, as well as the dependence of ultrastructure changes in muscle tissue mitochondria on the intensity of freezing. The animals were divided into three experimental groups: two groups were exposed to cryoinjury of different intensity, while the third was the control one. Cryoinjury was applied over an experimental after thawing were taken samples of muscle tissue for the analysis of content of energy phosphates and carbohydrates' metabolites, respectively, as well as for morphometric analysis of mitochondria volume out of frozen right and unfrozen left lower legs. Results obtained from different experimental groups were compared mutually and with control group that was not exposed to cryoinjury, respectively. It was found that the freezing in muscle tissue caused hydrops degeneration of mitochondria, depletion of energy reserves, reduction of energy status and the activation of mechanism of anaerobic metabolism. All these alterations were proportional to the intensity of freezing and considerably influenced contractility function of muscle cells, causing prolonged spasm of arterioles in thawed tissue, i.e., rigor congelationis that was primarily defined as an important factor in the pathogenesis of ischemic impairment of thawed tissues.

[Lateral orbitotomy in the approach to an orbital dermoid cyst]

The choice of surgical approach for the resection of orbital tumor is as a rule determined by the tumor position in the orbital space and the best choice is the most direct approach to orbital tumor. Lateral orbitotomy as the extracranial orbital approach is favorable for radical resection of the tumor, which growth is limited to the anterior, lateral and superolateral orbital segment.

[Experimental study of the pathogenesis of frostbite. Part II. Role of the sympathetic-adrenergic system in tissue reperfusion immediately after thawing]

The authors have investigated the role of sympathetic-adrenergic system in reperfusion of muscular tissue of the feet of Wistar rats immediately after thawing using alpha adrenergic blocker phentolamine methanesulfonate (Regitin). Cryoinjury was applied over an experimental model of local, controlled freezing of different intensity for certain experimental groups. Blood flow through microcirculation was measured by scintigraphy, following Tc-99m-pertechnetate clearance that was given in muscular mass of frozen right, as well as unfrozen left feet of rats. Results obtained in some experimental groups were compared mutually, as well as with the control group that was not exposed to cryoinjury. The investigations have revealed that immediately after thawing existed significant reduction, non-dependent of the intensity of freezing, in blood flow in microcirculation of both frozen and unfrozen feet of rats compared to the control group. Significant increase of microcirculatory blood flow in unfrozen feet was caused by blockade of sympathetic-adrenergic system, while the blood flow remained unchanged in the frozen ones. The reduction of blood flow in microcirculation of frozen tissues immediately after thawing was not associated with sympathetic-adrenergic factor.

Evaluation of autosomal dominant polycystic kidney disease by DTPA renal scintigraphy

Sixty patients with previously documented autosomal dominant polycystic kidney disease (ADPKD) were investigated using dynamic kidney scintigraphy with 99mTc-diethylenetriaminepentaacetic acid (DTPA). Patients were subdivided in respect of glomerular filtration rate (GFR) as follows: PKD I group (normal GFR), PKD II group (moderately reduced GFR), and PKD III (severely reduced GFR). Scintigraphic features, time activity curves, excretion parameters, global and individual kidney functions were analyzed. Because of GFR dependent sensitivity, in advanced renal failure being only 0.1, and low reproducibility (11% intraobserver, 22% interobserver), 99mTc-DTPA dynamic kidney scintigraphy cannot be generally recommended for the diagnosis of ADPKD, but has to become a routine method for functional evaluation of both global and individual renal functions, as well as degree of excretion disturbances in ADPKD patients.

[Experimental study of the pathogenesis of frostbite. Part I. Pathohistologic and ultrastructural changes in tissues immediately after thawing]

Histopathologic and ultrastructural changes in the tissues of frozen extremities of Wistar rats were investigated immediately after thawing. Three experimental groups were formed: two were exposed to cryoinjuries of different intensity, while the third was the control one. Cryoinjury was caused by experimental model of local, controlled freezing of hind, right extremities. Immediately after thawing the tissue samples were taken from frozen right and unfrozen left extremities, in which histopathologic and ultrastructural changes were compared mutually and with control group, respectively. It was observed that the freezing directly caused ultrastructural and histopathologic damage of the tissues that were manifested immediately after thawing and were proportional to the intensity of freezing. Simultaneously, in the tissues existed complex circulatory disorders manifested in open arteriovenous shunts, venous congestion and microcirculatory insufficiency caused by evident spasm of arteriolae that could be considered to be very significant pathogenetic factor in ischemic damage of unfreezed tissues.

Elevated tumour markers in patients with Balkan endemic nephropathy

Balkan nephropathy (BEN) is commonly associated with urothelial cancer. Urothelial cancer is manifested in the advanced stage of disease. The aim of this study was to facilitate early detection of urothelial cancer in BEN patients and their family members living in an endemic region by using tumour markers, carcinoembryonic antigen (CEA) and tissue polypeptide antigen (TPA), and a putative marker, ferritin. Fifteen BEN patients with normal renal function, 17 with renal failure (BEN-RF), 13 healthy members of their families (HFM), 14 patients with glomerulonephritis (GN) and 12 healthy controls (C) were studied. Serum CEA levels in BEN patients were within normal limits, however, in BEN-RF patients they were significantly increased over HFM (p<0.05). Serum TPA levels in BEN and BEN-RF patients were significantly higher than in the C and HFM groups (p<0.05). Urinary CEA was not significantly different between the groups studied. Urinary TPA levels in HFM (median 125 U/l, BEN (236 U/l) and BEN-RF (275 U/l) were significantly increased over C (30 U/l), however, TPA levels were increased also in GN patients (437 U/l). None of the BEN patients studied developed urothelial cancer during the ten years' follow-up. Markedly elevated urinary TPA-like levels in all patients studied (HFM, BEN, BEN-RF, GN) suggest that urinary TPA may not be a reliable tumour marker. However, the clinical relevance of high TPA levels in BEN patients should be evaluated.

[Epizootiologic situation of rabies in 1997. Urbanization of sylvatic rabies in Yugoslavia]

The Federal Republic of Yugoslavia is situated on the border of a great sylvatic rabies epizootics occurring in central and eastern Europe. That is the reason why a relatively small number of rabid animals have been registered. In 1997, 124 rabid animals, mainly red foxes, were identified. In recent years red fox rabies epizootics in Yugoslavia has annually spread 15-20 km to the south. Rabies in domestic animals, especially dogs, was characterized with furious clinical forms and dog-to-dog transmission typical of urban rabies. Sylvatic rabies has been almost completely eradicated in some countries of western Europe in the last years, mostly due to the method of oral vaccination of foxes-the main vector of rabies.

[Correlation of cytologic and pathohistologic findings in ultrasonically-guided thin-needle biopsy of abdominal and retroperitoneal organs]

The ultrasonically guided fine needle biopsy is cheap, very sensitive and specific method for the diagnosis of nonpalpable deep-seated lesions. During 1992 in the institute of Radiology of Military Medical Academy in Belgrade 87 biopsies of abdominal and 81 biopsies of retroperitoneal organs were performed for the cytological and histopathologic analysis. Deficient material was obtained in 15.4% of the cases. A good correlation between cytologic and histopathologic findings was observed, with diagnostic concordance in 90.8%. In 9 cases with falsely positive cytological diagnosis at the first examination, the diagnosis of malignancy was later confirmed by other diagnosis procedures. Diagnostic difficulties and the significance of adequate biopsy were particularly stressed.

[Repair of a severed nerve with denatured muscle graft--preliminary results of a new surgical technic]

In Neurosurgical Clinic of Military Medical Academy prospective study about the use of denatured muscle graft in nerve repair is in progress, based on numerous experimental and sporadic clinical literature data. The first, experimental part of the investigation is directed to operative technique details and also to find out the manner and duration of muscle denaturation which provide ideal conditions for regenerating axons sprouting. It is concluded that greater pectoral muscle have to be muscle graft donor for nerve defects shorter than 6 cm, and sartorius muscle for those longer than 6 cm. Denaturation for 30 seconds in liquid nitrogen and after that in distilled water for 3 minutes results in micromorphological status in muscle graft which is optimal for axonal regeneration. In the second, clinical part of the work reparations of missile neurotmesis of radial nerve with denatured muscle grafts are performed. Preliminary results 9 months after operation are quite comparable with results after sural nerve graft reparation.

[Personal experience with ex tempore diagnosis of neurosurgical biopsies using the smear method]

The results obtained by the use of the smear method were analyzed in ex tempore diagnostics of 240 neurosurgical biopsies, done in the period from 1991 to 1993. Thirty three different pathologic lesions were found that had their special morphology on smears, indicating the high specificity of this method. In 226 cases (94.17%) the diagnosis was established correctly, but in 14 cases (5.83%) it was not: in three cases the diagnosis was falsely negative and in 11 falsely positive. The main causes of the diagnostic errors were analysed and they included the subjective factors and uncommonness of the analyzed tissue samples. The accuracy of 94.17% enabled sufficiently reliable use of this method in ex tempore diagnostics of neurosurgical biopsies.

[Hemangiopericytoma of the lungs]

Six patients, three women and 3 men with lung hemangiopericytoma treated at the Military Medical Academy in the period 1971-1991 are reported. The youngest patient was 20 years, the oldest 69 years. Surgical treatment was performed in all patients, 3 lobectomies, one bilobectomy, one wedge resection and one extirpation. Multiple hemangiopericytoma was found in one patient which consisted of three separate tumours in the right lung. The other had solitary lesions. Malignant hemangiopericytoma, was found in 4 patients, one of them had metastases in the mediastinal lymphatic glands. Four patients are alive and are under control for nine years in the average without signs of recurrence.