Lloyd-model generalization: Conductance fluctuations in one-dimensional disordered systems

We perform a detailed numerical study of the conductance G through one-dimensional (1D) tight-binding wires with on-site disorder. The random configurations of the on-site energies ε of the tight-binding Hamiltonian are characterized by long-tailed distributions: For large ε, P(ε)∼1/ε^{1+α} with α∈(0,2). Our model serves as a generalization of the 1D Lloyd model, which corresponds to α=1. First, we verify that the ensemble average 〈-lnG〉 is proportional to the length of the wire L for all values of α, providing the localization length ξ from 〈-lnG〉=2L/ξ. Then, we show that the probability distribution function P(G) is fully determined by the exponent α and 〈-lnG〉. In contrast to 1D wires with standard white-noise disorder, our wire model exhibits bimodal distributions of the conductance with peaks at G=0 and 1. In addition, we show that P(lnG) is proportional to G^{β}, for G→0, with β≤α/2, in agreement with previous studies.

An embryological point of view on associated congenital anomalies of children with Hirschsprung disease

The most common congenital gut motility disorder is the Hirschsprung disease (HSCR). This anomaly is characterized by absence of neural crest-derived enteric neuronal ganglia. The aim of our study was to analyze the relationship between HSCR and other congenital anomalies or malfunctions. We examined 130 patients with Hirschsprung disease from Slovakia for last 10 years. During patients examination we focused not only on morphological abnormalities, but also functional anomalies. The incidence of associated congenital anomalies in our patients with HSCR was 26.1 %. But if we add functional defects (hypothyroidism, malfunction in cellular immunity, neurological deficit) to the morphological congenital abnormalities, the rate of the patients with HSCR with additional defects achieves 50.1 %. Nine of our patients (6.9 %) had syndromic HSCR. The most frequent disorder (13.6 % of patients) was primary deficiency in cellular immunity. More than 12.3 % of patients with HSCR had genitourinary abnormalities, in 10.0 % of patients variable degree of psychomotor retardation was observed, and skeletal, muscle and limb anomalies involved 7.7 % of patients. In 7.6 % cases of patients we found congenital hypothyroidism (including 2 cases of agenesis of thyroid gland). More than 6.1 % of patients presented with an associated anomaly in gastrointestinal tract (mostly anorectal malformations). Up to 5.5 % patients had congenital anomaly of heart, 3.8 % had ophthalmic and 3.1 % had craniofacial anomalies. Down syndrome was the main diagnosis in 3.8 % patients. We discussed  the relationship between HSCR and other anomalies, which are probably caused by abnormal migration, proliferation, or differentiation, of neural crest cells during embryogenesis (Tab. 1, Fig. 2, Ref. 75).

[Functional morphology of recently discovered telocytes inside the female reproductive system]

Discovery of telocytes has become an important and key challenge in past few years. These cells are interstitial cells extending very long cytoplasmic processes named telopodes, by which they create functional networks in the interstitium of different organs. Telocytes are considered to be connective tissue elements that create contacts among each other, but they also function as intercellular structures, functionally connected with cells of the immune system, neurons and smooth muscle cells. Telocytes can be found also in the different parts of female reproductive system with functions and purpose, which is summarized in our overview. Telocytes regulate for example peristaltic movements in fallopian tubes. The decrease of their number (due to inflammatory disease or endometriosis) causes impairment in transport through fallopian tubes which may result in sterility or tubal gravidity. In uterus they regulate contraction of myometrial smooth muscle (blood expulsion in menstrual phase, childbirth) as well as they contribute in immunological care during embryo implantation. Telocytes probably control also the involution of uterus after delivery. Their function in vagina has not been yet clearly defined; they probably take part in slow muscle contraction movement during sexual intercourse. In mammary glands some scientists suppose their function in control of cell proliferation and apoptosis, that is why, they may play a role in carcinogenesis. In placenta they probably monitor and regulate flow of blood in vessels of chorionic villi and they may be responsible also for etiopathogenesis of pre-eclampsy. All these mentioned functions of telocytes are only in the level of hypothesis and have been published recently. New research and studies will try to answer the questions whether telocytes play a key role in these processes. Our review we completed with some original microphotographs of telocytes in different organs of female reproductive system.

Ten-year survival and prognostic markers in one thousand patients with advanced heart failure. A single-centre analysis

AIM

Patients with advanced heart failure (HF) represent a pool of candidates for heart transplantation and long-term mechanical circulatory support devices. The aim of our study was to determine simple and reliable markers of one-year mortality for selection of the most suitable patients for heart replacement therapy.

METHODS AND RESULTS

One thousand consecutive patients with HF (mean age 49 ± 10.9 years; 86.8% males) referred to a single tertiary centre from January 1998 to January 2010 in order to assess the indication for heart transplantation were enrolled. Kaplan-Meier survival analysis was performed. Independent mortality predictors were established using logistic regression analysis. The mean follow-up was 4.3 ± 2.7 years (range 1-12 years). Cumulative survival was as follows: 1-year survival 83%, 3-year 63%, 5-year 50%, 7-year 39%, and 10-year 23%. Independent predictors of 1-year mortality included coronary artery disease, left ventricular diastolic diameter >79 mm, plasma sodium <135 mmol/L, the need for intravenous treatment at hospital admission (diuretics and/or inotropes), and furosemide dose at discharge >240 mg/day.

CONCLUSIONS

Short-term prognosis of HF patient can be estimated based on simple parameters. Patients with signs of poor prognosis should be referred to tertiary centres to be considered for heart replacement therapy.

Ultrastructural analysis of different human mesenchymal stem cells after in vitro expansion: a technical review

Transmission electron microscopy reveals ultrastructural details of cells, and it is a valuable method for studying cell organelles. That is why we used this method for detailed morphological description of different adult tissuederived stem cells, focusing on the morphological signs of their functions (proteosynthetic activity, exchange with external environment, etc.) and their comparison. Preparing a specimen from the cell culture suitable for transmission electron microscopy is, however, much more challenging than routine tissue processing for normal histological examination. There are several issues that need to be solved while working with cell pellets instead of solid tissue. Here we describe a simple protocol for the isolation and culture of mesenchymal stem cells from different adult tissues, with applications to stem cell biology and regenerative medicine. Since we are working with population of cells that was obtained after many days of passaging, very efficient and gentle procedures are highly necessary. We demonstrated that our semi-conservative approach regarding to histological techniques and processing of cells for transmission electron microscopy is a well reproducible procedure which results in quality pictures and images of cell populations with minimum distortions and artifacts. We also commented about riskiest steps and histochemical issues (e.g., precise pH, temperature) while preparing the specimen. We bring full and detailed procedures of fixation, post-fixation, infiltration, embedding, polymerization and contrasting of cell obtained from in vitro cell and tissue cultures, with modifications according to our experience. All this steps are essential for us to know more about adult stem cells derived from different sources or about other random cell populations. The knowledge about detailed ultra-structure of adult stem cells cultured in vitro are also essential for their using in regenerative medicine and tissue engineering.

Cardiovascular Screening and Management Among Kidney Transplant Candidates in Hungary

INTRODUCTION

Cardiovascular disease is a major cause of morbidity and mortality in end-stage renal disease patients on dialysis and the most common cause of death in the immediate post-transplantation period. The aim of our study was to describe a novel approach of cardiovascular screening and management of dialysis patients evaluated for the transplant waiting list.

METHODS

Twenty-eight patients with end-stage renal disease put on the waiting list between July 2013 and July 2014 were subjected to a prespecified cardiovascular screening protocol utilizing noninvasive and/or invasive tests. Patients were subsequently divided into 3 strata in terms of their estimated cardiovascular risk. Each of these groups were then prescribed interventions aiming to improve their cardiovascular condition.

RESULTS

According to our prespecified protocol of cardiovascular screening studies, 15 (54%) patients were identified as low, 5 (18%) as intermediate, and 8 (28%) as high risk. Four (14%) patients were current smokers. In the low-risk group, we initiated a patient education program involving counseling on regular exercise such as swimming or cycling to improve their functional capacity. In the high-risk group revascularization was done in 5 cases (63%), including 3 percutaneous transluminal coronary angioplasties (PTCA) with stents for single-vessel disease, and coronary artery bypass graft surgeries (CABG) for triple-vessel disease in 2 cases. In the medium-risk group medical management was opted for, including introduction of beta-blockers, inhibitors, statins, and ezetimibe, as well as efforts to optimize anemia management, indices of bone-mineral disease, and fluid status.

CONCLUSION

In our regional transplant program, we introduced a comprehensive multidisciplinary approach to treat potential transplant candidates according to cardiovascular risk stratification based on a prespecified screening protocol. Further studies are needed to correlate this novel strategy with post-transplantation outcomes.

Congenital absence of the portal vein--Case report and a review of literature

Congenital absence of the portal vein (CAPV) is a rare anomaly in which the intestinal and the splenic venous drainage bypass the liver and drain into systemic veins through various venous shunts. To our knowledge, we have reviewed all 83 cases of CAPV, since first described in 1793. This equates to a rate of almost 2.5 cases per year over the last 30 years. Morgan and Superina (1994, J. Pediatr. Surg. 29:1239-1241) proposed the following classification of portosystemic anomalies; either the liver is not perfused with portal blood because of a complete shunt (Type I) or the liver is perfused with portal blood due to the presence of a partial shunt (Type II). In our case, abdominal venous blood drained into the suprarenal inferior vena cava via the left renal vein and dilated left gastric veins. After analyzing all reported cases, we recognize that more than 65% of patients are females and more than 30% of all published cases had been diagnosed by the age of 5 years. Additional anomalies are common in CAPV. In the reported cases, more then 22% of patients had congenital heart disease. Other commonly found anomalies include abnormalities of the spleen, urinary and male genital tract, brain as well as skeletal anomalies. Hepatic changes such as focal nodular hyperplasia, hepatocellular carcinoma, and hepatoblastoma are diagnosed in more then 40% of patients. This article also illustrates the radiological findings of CAPV. Radiological evaluation by ultrasound, CT, and MRI is helpful to detect coexisting abnormalities.

Periodontitis and osteoporosis

Today's knowledge and studies show a firm correlation between osteoporosis and periodontitis, particularly in postmenopausal women. This review study deals with epidemiological and etiopathogenetic association between chronic periodontitis and an osteoporosis. A special emphasis is put on explanation of possible relations between a premature tooth loss and decrease of length and density of jaw bones, particularly their alveolar prolongations. The second part of the paper deals with principles of treatment in patients suffering of osteoporosis. Osteoporosis reduces density of jaw bones and decreases a number of teeth in jaws, but it does not affect other clinical signs and markers of periodontitis such as inflammation, bleeding and the depth of periodontal pockets and microbial plaque.

[New views on the functional morphology of human clitoris]

The clitoris is the female external sexual organ and is composed of erectile bodies. The distal portion of the vagina, clitoris and urethra form an integrated entity sui generis. All these components share a common vasculature and nerve supply and during sexual stimulation they respond as one functional unit. The clitoris is closely linked to the mechanism of sexual arousal in women. Glans has a dense network of receptors, innervated often with a several nerves at the same time - taking care of tactile sensitivity, thus, standing on the beginning of the journey, which culminates in orgasm. Nervus dorsalis clitoridis, which is a branch of n. pudendus, takes care of sensitive innervation. For blood supply is responsible a. clitoridis, which is a branch of a. pudenda interna. The most common congenital developmental anomalies of the clitoris include: clitoromegaly, penis-like clitoris and bifid clitoris. All, however, are among the relatively rare birth defects. Mechanism of orgasm gets attention between both laic and scientific community, although to this date there are speculations about its exact mechanism. There is relevant opinion, influenced by Freuds doctrine, which strictly recognizes two kinds of female orgasms - vaginal and clitoral, and, according to proponents of this theory, only the second mentioned is caused by stimulation of the clitoris. The second school unifies the term orgasm and claims that only clitoral stimulation (digital, penile, cunnilingus) and contraction of striated perineal muscle are responsible for orgasm, whether the glans (external part) or the body of the clitoris from the vaginal approach is stimulated. Therewithal, special term for mythical and still undocumented (despite many attempts and bold claims about its finding) G spot (named after Ernst Gräfenberg, a German doctor who predicted the existence of this place) is redundant. Important role in the regulation of female sexuality and responsiveness play a hormonal influences and varying concentrations of neurotransmitters.

The normal human newborns thymus

The thymic microenvironment constitutes a unique cell environment composed of thymic epithelial cells, myoid cells, and bone marrow-derived accessory cells for the differentiation, maturation and selection of T lymphocytes. The histological feature of thymus is markedly dependent on the age of individual and on various negative stimuli. Our study group consisted of fourteen newborns whose thymuses were removed during surgery performed for various congenital heart defects. We used a palette of seven monoclonal antibodies for exact localization of different cells creating the thymic microenvironment (cytokeratin AE1/AE3, desmin, actin, S100 protein, CD68, CD20, and CD45RO) as well as three monoclonal antibodies against proteins regulating the process of apoptosis (bcl2 oncoprotein, p53 protein, and survivin). We described and microphotographically illustrated the localization of thymic cytokeratin AE1/AE3-positive epithelial cells (subcapsular part of the cortex and medulla, especially Hassall's corpuscles), dendritic cells (medulla, often inside the Hassall's corpuscles), thymic myoid cells (medulla, often in close contact with Hassall's corpuscles), macrophages (mostly cortex, but also medulla and inside the Hassall's corpuscles), B lymphocytes (thymic medulla) and CD45RO-positive T lymphocytes (mostly thymic cortex). We found p53-positive thymic epithelial cell nuclei in subcapsular part of cortex and in outer epithelial cell layer of Hassall's corpuscles (very similar to the basal layer of epidermis). Bcl2 positive lymphocytes were mostly localized in thymic medulla, especially nearby Hassall's corpuscles. The thymuses were mostly survivin-negative with exception of round cells in border between cortex and connective tissue septa (probably migrating progenitor cells) (Tab. 1, Fig. 14, Ref. 66).

The long-term response to treatment with calcium channel blockers in a patient with idiopathic pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a disease characterised by a gradual increase in resistance of pulmonary circulation leading to right ventricular failure and death. In only 10 % of cases, there is a response to acute vasoreactivity testing with a significant reduction in mean pulmonary artery pressure (PAP), while in this group of patients, less than one half of cases benefit from long-term treatment with calcium channel blockers (CCB). This paper describes a case report of a young patient with dyspnoea and suspicion of pulmonary hypertension who was referred to a specialised centre. The complex evaluation of her clinical state led to confirmed diagnosis of idiopathic pulmonary arterial hypertension (IPAH). Because there was a positive response to vasoreactivity testing, the treatment for IPAH was initiated with a high dose of CCB. This treatment markedly improved her clinical state as well as echocardiographic and hemodynamic findings.In this study, the authors present a diagnostic algorithm in pulmonary hypertension and emphasise the role of CCB in treatment of PAH in carefully selected patients (Tab. 1, Fig. 5, Ref. 7).

Drug-induced gingival enlargement

OBJECTIVES

Side effect of medicamentous treatment in hypertension therapy and angina pectoris with calcium channel blockers related to fibrotic gingival enlargement were examined.

METHODS

In our study we deal with clinico-histopathological and microbiological knowledge from this field underpinned by two case reports treated with antihypertensive therapy using calcium channel blockers. In the first case report we were largely concerned with microbiological findings from the area of periodontal pseudopockets diagnosed through a DNA analysis and appropriate antibiotic therapy. In a patient treated with a preparation from amlodipine group we proceeded to a complex treatment involving the change of hypertension therapy, introduction of professional and home oral hygiene and also following surgical and prosthetico-aesthetic rehabilitation.

RESULTS

Case Report 1 who was for a long term medicated with a preparation from the nifedipine group of antihypertensives we detected the presence of periodontal pseudopockets with probing depth of 4 to 7 mm with positive BOP and with marked rigid fibrotic gingival enlargement accompanied with considerable foetor ex ore. In a patient from the Case Report 2 who was for a long term medicated with a preparation from the amlodipine group of antihypertensives with large gingival overgrowth angiogenesis was characterized by cuboidal endothelial cell lining. In the samples under a layer of stratified epithelium there was present dense fibrous connective tissue comprising largely of collagen fiber bundles.

CONCLUSION

Bacterial composition in the patient with a high degree of gingival enlargement and periodontal pseudopockets 4 to 7 mm deep represented a typical spectrum of bacteria occuring in chronic forms of periodontitis. However, we cannot determine, if such distribution of bacteria was primary before the application of nifedipine antihypertensives, or it originated later after the formation of typical anaerobic setting of false periodontal pockets.

First experience with single incision laparoscopic surgery in Slovakia: concomitant cholecystectomy and splenectomy in an 11-year-old girl with hereditary spherocytosis

AIMS

Hereditary spherocytosis is an autosomal dominant inheritance disorder of the red blood cell membrane characterized by the presence of spherical-shaped erythrocytes (spherocytes) in the peripheral blood. The main clinical features include haemolytic anemia, variable jaundice, splenomegaly and cholelithiasis caused by hyperbilirubinemia from erythrocyte hemolysis. Splenectomy does not solve the congenital genetic defect but it stops pathological hemolysis in the enlarged spleen. If gallstones are present, it is appropriate to perform cholecystectomy at the time of splenectomy, although the patient has symptoms of gall bladder disease. We present the case of single incision laparoscopic surgical (SILS) concomitant splenectomy and cholecystectomy performed with conventional laparoscopic instruments in an 11-year-old girl with the diagnosis of hereditary spherocytosis.

METHODS

A 2-3 cm umbilical incision was used for the placement of two 5 mm trocars and one 10 mm flexible videoscope. Conventional laparoscopic dissector, grasper, Ligasure, Harmonic Ace and hemoclips were the main tools during surgical procedure. We prefer Single Incision Laparoscopic Surgery Foam Port (Covidien) as the single umbilical device for introduction into the abdominal cavity. First, we performed cholecystectomy, then the gallbladder was put aside over the liver and after that we peformed splenectomy. To remove the detached spleen and gallbladder, a nylon extraction bag is introduced through one of the port sites. The spleen is than morcellated in the bag with forceps and removed in fragments. After that we removed them and the umbilical fascial incision was closed.

RESULT

Splenectomy is the only effective therapy for this disorder and often it is performed in combination with cholecystectomy. Conventional surgery requires a wide upper abdominal incision for correct exposure of the gallbladder and spleen. Our experience shows that SILS splenectomy and cholecystectomy is feasible even in young children and despite the small number of cases in the world, we consider the combined laparoscopic approach safe and effective for the treatment of hereditary spherocytosis.

CONCLUSION

According to actually published guidelines, the laparoscopic approach to concomitant splenectomy and cholecystectomy is recommended, but it depends on the availability of appropriately trained surgeons and suitable equipment.

The effect of simvastatin on lipid droplets accumulation in human embryonic kidney cells and pancreatic cancer cells

Background

Statins (HMG-CoA reductase inhibitors) represent a major class of compounds for the treatment of hypercholesterolemia due to their ability to inhibit de novo cholesterol synthesis. In addition to their hypolipidemic effects, chemoprotective properties have been attributed to statins as well. These effects involve multiple mechanisms, which, however, are not known in detail. The aim of our study was to assess in non-malignant as well as cancer cells the impact of simvastatin on the amount of cytosolic lipid droplets (LDs) implicated in many biological processes including proliferation, inflammation, carcinogenesis, apoptosis, necrosis or growth arrest.

Methods

Human embryonic kidney cells HEK-293T and human pancreatic cancer cells MiaPaCa-2 were treated with simvastatin (6 and 12 μM) for 24 and 48 hours respectively. Neutral lipid probe Nile Red was used for detection of LDs by fluorescence microscopy. Cellular cholesterol content was determined by HPLC. Changes in expression of genes related to lipid metabolism in simvastatin-treated MiaPaCa-2 cells were examined by DNA microarray analysis. Validation of gene expression changes was performed using quantitative RT-PCR.

Results

The treatment of the cells with simvastatin increased their intracellular content of LDs in both non-malignant as well as cancer cells, partially due to the uptake of cholesterol and triacylglyceroles from medium; but in particular, due to enhanced synthesis of triacylglyceroles as proved by significant overexpression of genes related to de novo synthesis of triacylglyceroles and phospholipids. In addition, simvastatin also markedly influenced expression of genes directly affecting cell proliferation and signaling.

Conclusions

Simvastatin treatment led to accumulation of cytosolic LDs within the examined cells, a phenomenon which might contribute to the antiproliferative effects of statins.

Poland syndrome: from embryological basis to plastic surgery

Poland syndrome is a rare congenital anomaly described by Sir Alfred Poland over 170 years ago. Combination of unilateral aplasia of the sternocostal head of musculus pectoralis major, and an ipsilateral hypoplastic hand with simple syndactyly and short fingers is typical for this condition. It occurs more frequent among males, and is usually situated on the right hemithorax in the unilateral form. The pathogenesis of Poland syndrome is not clear. Most of the authors assume that the etiologic insult is vascular in nature. During the sixth week of gestation, not only the pectoral mass splits (future muscles of the thorax) and intervening tissue between the finger rays of hands starts to disappear but also the vascular differentiation from six aortic arches begins. In our paper we report two cases of children with Poland syndrome, who underwent surgical procedure in the Department of Pediatric Surgery, Comenius University in Bratislava, Slovakia. Our case reports are focused on pre-operatively and also post-operatively imaging (RTG, CT, and 3D CT imaging) of the affected thorax and arm, as well as the operative reconstruction technique of abnormal ribs. We also discussed the possible embryonic backgrounds of this anomaly as well as the importance of plastic surgery resulting in patients' normal life.

[The structural basis for transport through the Fallopian tube]

The Fallopian tube has until recently been a neglected structure, bypassed by in vitro fertilization and seen only as a tube that transports the oocyte or early embryo to the uterus. More recently, its role is even more undervalued after the introduction of techniques of assisted reproduction, in which the Fallopian tubes become like unnecessary. The Fallopian tube performs several important functions. It captures the oocyte after ovulation, maintains and controls the migration of spermatozoa to the site of fertilization. It provides the special microenvironment for fertilization; nourishes the early embryo while it is being carried to the uterus and amplifies signals from embryo to the mother. In our article we conducted a systematic review of relevant articles found in PubMed, Scopus and ISI Web of Knowledge, focused on the new insights into the functional morphology of Fallopian tube. We described the possible function of muscle layer motility, ciliary activity and tubal fluid movement on transport of gamets / embryo, as well as we mentioned the negative factors (such as smoking, chlamydial infection or endometriosis) affecting the transport through the Fallopian tube.