[DIFFICULTIES IN DISSECTION OF URINARY BLADDER IN TOTAL LAPAROSCOPIC HYSTERECTOMY.]

The dissection of urinary bladder is a crucial phase of the laparoscopic operation of hysterectomy. The latter dissection may become even more difficult in the context of history of operative interventions as cesarean section or cervical conization, presence of cervical or isthmic myomatous nodes, as well as upon a bad operative technique. The obeying of some basic principles (knowledge of pelvic anatomy and topographic interrelations; considering of present risk factors; intraoperative screening for complications and their early treatment) results in the optimal performance of laparoscopic hysterectomy.

[Ultrasound Examination and Management of Twin Pregnancy.]

Twin pregnancies are found in about 3 % of all pregnancies and 2/3 are dizygotic and 1/3 are monozygotic. In the last 30 years after the introduction of assisted conception and increasing maternal age the rate of twin pregnancies dramatically increased. Compared to singletons, twins have more complications such as intrauterine demise, intrauterine selective fetal growth reStriction, congenital anomalies, miscarriage and preterm labour. Monochorionic twins are at high risk for unique complications because of blood exchange through vascular communications in the shared placenta. Twin pregnancies should be considered as a high risk pregnancies and the well-being of the two fetuses should be taken into account with a strict protocol for follow up and management options. CONCLUSION: Ultrasound examination olavs a maior role in fetal surveillance.

[A Case of Isolated Massive Pre-sacral Lymph Node Metastasis in 1B1 Stage Cervical Cancer - Case Report.]

The article presents a rare case of isolated massive pre-sacral metastasis in first stage cervical cancer. A 64 year old patient, which on occasion genital bleeding is made D&CI and histologically proven a "cancer of the cervix." Last period - 6 years ago. Clinically a patient diagnosed as IBI stage according to FIGO criteria. Surgery was radical hysterectomy (Class Ill) and pelvic and paraaortic lymph node dissection. HiStological result of the preparation is: vagina - clean resection lines, parameters - connective tissue and vessels, endometrium - atrophic changes, paraaortic lymph nodes - without metastases, cervix - infiltrative ulcerous adenosquamous carcinoma size vertically -4 cm. and -3.5 cm horizontally. Hitopathological diagnosis confirmed the clinical - pTlblNlMx.

Association of rs172378 C1q gene cluster polymorphism with lupus nephritis in Bulgarian patients.

INTRODUCTION: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that can affect substantially any organ in the body. One of its most severe manifestations is lupus nephritis. Hereditary C1q deficiency is strongly related to SLE but there are very few and inconsistent studies exploring the single nucleotide polymorphisms (SNPs) of the C1q gene cluster in relation to the pathogenesis of SLE. In the present study we evaluated the possible association of gene variants in complement C1q gene cluster with susceptibility to lupus nephritis in a Bulgarian population, focusing on five previously associated with SLE SNPs in other populations. MATERIALS AND METHODS: Thirty-eight patients with lupus nephritis and 185 healthy controls, all from Bulgaria, were genotyped for the five C1q SNPs, rs587585, rs292001, rs172378, rs294179 and rs631090, by quantitive real-time PCR methods. We also determined C1q serum levels of C1q and haemolytic activity of C1q in relation to C1q genotypes. RESULTS: Lupus nephritis patients and healthy controls had statistically similar frequencies of genotypes and alleles of rs587585, rs292001, rs294179 and rs631090 SNPs. Nevertheless, minor G allele in rs172378 was significantly overrepresented in lupus nephritis patients when compared with healthy controls (36% vs. 23%, odds ratio = 1.80, 95% confidence interval = 1.06-3.06, p = 0.029). The SNP rs292001 showed a trend towards lower serum C1q levels in healthy controls. Two SNPs - rs294179 and rs292001 - were in a linkage disequilibrium in patients and healthy controls with different power (healthy controls: r (2 )= 0.6526, D' = 0.842; lupus nephritis patients: r (2 )= 0.491, D' = 0.686). The haplotype C-A-A-T-T in the patient group was associated with lupus nephritis: 7.7% vs. 0.8%, odds ratio = 10.81, 95% confidence interval = 1.45-80.57, p = 0.002. CONCLUSIONS: These results support the implication of the G allele in rs172378 as a risk factor for lupus nephritis in a homozygous status, at least for a Bulgarian population.

[THE ROLE OF THE CYTOKINE PROFILE IN TREATMENT IN WOMEN WITH ENDOMETRIAL CANCER FIRST STAGE].

Endometrial canceris the most common gynecological cancer. It is positive that more than 53% of diagnosed cases of endometrial cancer are in first stage when the therapeutic options are more successive. More and more gynecologists in addition to the normal clinical and histological tests expand the information for the neoplastic process with biochemical and immunological markers-tumor markers, hormones, lymphocyte population, cytokines, markers for lesion-inflammatory processes, etc. Several biological mechanisms track the connection between overweight and endometrial neoplastic risk. In the surgical practice is increasing the interest towards the cytokine group as independent prognostic factors, aggressiveness and options for treatment of the neoplastic process. The cytokine profile can be used as factor for evaluation of the primary neoplastic immune impairment as well as for a choice of surgical intervention. This is extremely important for obese patients because obesity is turning into worldwide medico-social problem.

[Evaluation of the expression of S100A1 protein in serous, mucinous and endometroid ovarian carcinoma].

According to literature approximately 60% from all ovarian malignances express epithelial phenotype. According to their histomorphological characteristics, epithelial ovarian tumors are divided into eight groups. In some particular cases, separate histological types are hard to distinguish one from another. Recent studies show the presence of beneficial effect of adjuvant radiotherapy on most of the early ovarian carcinomas (all, except serous carcinomas). In renal cell carcinomas SI00A 1 is used to distinguish between different subtypes of the malignancy. Forty cases of ovarian carcinomas were analyzed in a retrospective study. Immunohistochemical evaluation of the S100A1 protein expression was carried out on representative archival formalin -fixed -paraffin-embedded tissue materials. Positivity for S100A1 was observed in 31 (77.50%) of the studied cases. Twenty-seven out of thirty-two (84.38%) cases of serous ovarian carcinoma were found to express S100A1. S100A1 expression was observed in one out of the two mucinous and three out of the six endometroid ovarian carcinomas. Immunopositivity was nuclear, cytoplasmic or nuclear and cytoplasmic in serous carcinomas, nuclear in the one positive mucinous carcinoma and sytoplasmic in the three imunopositive endometroid ovarian carcinomas. The S100A1 immunohistochemical marker is not likely to be useful in clinical practice to distinguish between different histological subtypes of ovarian cancer. The large percentage of S100A1 positivity in serous ovarian carcinomas needs a better understanding.

[Investigation of S100A1 expression in normal ovarian tissues].

The S100 protein family includes low-molecular weight (16-26 kDa) calcium-binding proteins. During the last decade data demonstrating the increased S100A 1 expression in several types of tumors was published. The authors of the basic studies, concerning the role of S100A1 expression in ovarian carcinomas emphasize the insignificant rate of S100A1 expression in normal ovarian tissues. So far the SI00A1 expression in ovarian tissues is based on tissue microarrays in limited number of cases. In order to be useful as biomarker for malignancy, S100A1 expression should be unequivocally negative or low in normal ovarian tissues. In order to ensure the application of S100A1 as biomarker for malignancy, a more detailed information on its' expression in normal ovarian structures is needed. This study aimed to evaluate the expression of S100A1 using immunohistochemical method in morphologically normal ovarian. Tissue samples from 40 ovaries were retrospectively studied. Immunohistochemical staining for S1001A1 was preformed in accordance to standard laboratory protocol. The immunopositivity was evaluated and interpreted in the context of the histomorphological findings in the analyzed ovarian tissues. Some benign (normal) ovarian tissue components were found to be S100A1 positive. Immunopositive in normal ovaries was found in: nerves and nerve endings, cells of rete ovarii, granulosa cells of follicular cysts, granulosa-lutein cells of corpus luteum, and corpus luteal cyst and in the granulosa cells in mature follicles. Immunopositivity in those cases was cytoplasmic, nuclear, or cytoplasmic/nuclear. Intensity of nuclear staining was found to vary from weak/moderate to high. Inclusion epithelial cysts were found to be negative for S100A1. The immunohistochemial staining for S100A1 in benign ovarian tissues may be useful for differentiating follicular from inclusion cysts (which have limited if any clinical importance). More importantly, the present study demonstrated expression of S100A1 in several normal tissue structures, which positivity would lead to very low levels of specificity of S100A1 if used as indicator for malignancy.

Comparative in vitro activity of tigecycline and other antimicrobial agents against Shigella species from Kuwait and the United Arab of Emirates.

Shigella species isolated from stool samples of symptomatic patients of all age groups at the Mubarak Al Kabir Hospital and Infectious Diseases Hospital, Kuwait and Tawam Hospital, UAE during a 2-year period were investigated for their susceptibility to tigecycline and several other antibiotics by determining the minimum inhibitory concentrations (MICs) using the E test method. A total of 100 and 42 strains were collected from UAE and Kuwait, respectively. The extent of drug resistance in the Shigella spp. isolates from these two countries was analyzed by criteria recommended by the Clinical and Laboratory Standards Institute (CLSI). Amikacin, cefotaxime, cefuroxime, ciprofloxacin, imipenem, meropenem, piperacillin-tazobactam and tigecycline had excellent activities against all isolates from UAE and Kuwait with MIC(90s) of 12, 0.094, 4, 0.012, 0.25, 0.032, 3 and 0.25 microg/ml and 4, 1, 4, 0.125, 0.38, 0.19, 3 and 0.25 microg/ml, respectively. Half of all isolates from both countries were resistant to ampicillin. None of the isolates in Kuwait was resistant to amoxicillin-clavulanic acid compared with 22% in UAE. Resistance to chloramphenicol was recorded in 50 and 36% of the isolates in Kuwait and UAE, respectively. The percentages of non-susceptibility to trimethoprim-sulfamethoxazole and tetracycline were very high in Kuwait and UAE (76% vs. 92% and 76% vs. 98%, respectively). Notably, one isolate, S. flexneri, from UAE had reduced susceptibility to ciprofloxacin (MIC, 0.25 microg/ml). Four (2.8%) of the isolates were ESBL producers by the E test ESBL method but could not be confirmed by PCR using primers for bla(CTX-M), bla(SHV) and bla(TEM). In conclusion, Shigella spp. isolated from symptomatic patients in Kuwait and the UAE demonstrated high rates of resistance to the first-line antibiotics but very susceptible to the carbapenems, cephalosporins, fluoroquinolones and tigecycline. Tigecycline holds promise as a potential drug of choice for the therapy of severe shigellosis.

Detection of mutations in the gyrA gene in fluoroquinolone resistance Salmonella enterica serotypes typhi and paratyphi A isolated from the Infectious Diseases Hospital, Kuwait.

BACKGROUND: Enteric fever due to Salmonella enterica is a major health problem, and fluoroquinolones such as ciprofloxacin are mostly the antibiotic of choice for treatment. Resistance to ciprofloxacin has been noticed to increase due to the emergence of new mutations in the bacterial DNA. AIMS: To explore the fluoroquinolone resistance and molecular characterisation of reduced quinolone susceptibility in S typhi and S paratyphi A in Kuwait. METHODS: 136 clinical isolates of S typhi and 40 of S paratyphi A were collected over five years. The antimicrobial susceptibility was studied by various methods. DNA sequencing of gyrA, gyrB, parC and parE genes was performed in 31 isolates. RESULTS: There was a substantial difference in MIC range between the two serotypes, with the most common MIC for S typhi being 0.25 mg/l and for S paratyphi A being 1 mg/l. The proportion of nalidixic acid resistant strains increased gradually over the years. These strains had a significantly higher range of MIC of ciprofloxacin (0.023 mg/l to 1.0 mg/l) compared to the nalidixic acid sensitive strains (0.0016 mg/l to 0.125 mg/l). DNA sequencing of gyrA gene showed the presence of three different point mutations: Ser83-->Phe in 17 strains, Ser83-->Leu in 3 strains and Asp87-->Asn in 6 strains. No mutations in the other genes were found. CONCLUSIONS: It is very important to keep searching for new mutations and continuously monitor drug resistance in different parts of the world in order to efficiently manage cases with enteric fever.

Surveillance of antibacterial resistance in Staphylococcus aureus isolated in Kuwaiti hospitals.

OBJECTIVE: To investigate the prevalence of antibiotic resistance among Staphylococcus aureus isolated in Kuwaiti hospitals. MATERIALS AND METHODS: S. aureus were isolated and identified following standard microbiological methods. Antibacterial susceptibility test was performed by disk diffusion and the measurement of minimum inhibitory concentration with E-test strips. RESULTS: A total of 1,846 S. aureus isolates were analyzed from 13 hospitals between 1 March and 30 October 2005. They were isolated from 1,765 (95.6%) inpatients and 81 (4.4%) outpatients. Methicillin resistance was detected in 588 (32.0%) of the isolates. The methicillin-resistant S. aureus (MRSA) consisted of 461 (78%) multiresistant and 127 (22%) nonmultiresistant isolates. The nonmultiresistant MRSA consisted of epidemic MRSA-15 and community-associated MRSA. The community-associated MRSA was detected in all hospitals with MRSA, indicating its establishment in Kuwaiti hospitals. The proportion of isolates resistant to gentamicin, kanamycin, erythromycin, tetracycline, ciprofloxacin, fusidic acid and trimethoprim was higher among MRSA than methicillin-susceptible S. aureus (MSSA) isolates. Twenty-four and 22% of MRSA and MSSA isolates, respectively, expressed reduced susceptibility to vancomycin (minimum inhibitory concentration = 3-4 mg/l). CONCLUSION: The study revealed the presence of methicillin resistance in 32% of S. aureus isolated in Kuwaiti hospitals and revealed an increase in the number of MRSA and MSSA with reduced susceptibility to vancomycin.

Pleiotrophin disrupts calcium-dependent homophilic cell-cell adhesion and initiates an epithelial-mesenchymal transition.

Regulation of the levels of tyrosine phosphorylation is essential to maintain the functions of proteins in different signaling pathways and other cellular systems, but how the steady-state levels of tyrosine phosphorylation are coordinated in different cellular systems to initiate complex cellular functions remains a formidable challenge. The receptor protein tyrosine phosphatase (RPTP)beta/zeta is a transmembrane tyrosine phosphatase whose substrates include proteins important in intracellular and transmembrane protein-signaling pathways, cytoskeletal structure, cell-cell adhesion, endocytosis, and chromatin remodeling. Pleiotrophin (PTN the protein and Ptn the gene) is a ligand for RPTPbeta/zeta; PTN inactivates RPTPbeta/zeta, leaving unchecked the continued endogenous activity of tyrosine kinases that increase phosphorylation of the substrates of RPTPbeta/zeta at sites dephosphorylated by RPTPbeta/zeta in cells not stimulated by PTN. Thus, through the regulation of the tyrosine phosphatase activity of RPTPbeta/zeta, the PTN/RPTPbeta/zeta signaling pathway coordinately regulates the levels of tyrosine phosphorylation of proteins in many cellular systems. We now demonstrate that PTN disrupts cytoskeletal protein complexes, ablates calcium-dependent homophilic cell-cell adhesion, stimulates ubiquitination and degradation of N-cadherin, reorganizes the actin cytoskeleton, and induces a morphological epithelial-mesenchymal transition (EMT) in PTN-stimulated U373 cells. The data suggest that increased tyrosine phosphorylation of the different substrates of RPTPbeta/zeta in PTN-stimulated cells alone is sufficient to coordinately stimulate the different functions needed for an EMT; it is possible that PTN initiates an EMT in cells at sites where PTN is expressed in development and in malignant cells that inappropriately express Ptn.

Plasmid-mediated high-level ceftriaxone resistance in a Salmonella enterica serotype typhimurium isolate.

OBJECTIVE: To present the first documented case of acute infectious gastroenteritis caused by high-level ceftriaxone-resistant Salmonella enterica serotype typhimurium in Kuwait. SUBJECT AND METHODS: Isolation from stool specimen and species identification of current enteric pathogen was carried out according to standard methods. Susceptibility to antibiotics was determined by the disc diffusion method on Mueller-Hinton agar. Minimal inhibitory concentrations (MICs) were measured with E-test strips. The production of extended spectrum beta-lactamase (ESBL) was studied by the double disc synergy method and E-test ESBL strips. Plasmid DNA isolation was performed by the rapid alkaline lysis method. Plasmid DNA was transferred by conjugation to a recipient strain of Escherichia coli. RESULTS: The isolate of S. enterica serotype typhimurium was resistant to ceftriaxone (MIC >256 mg/l), cefotaxime and ceftazidime, and produced ESBL. Ceftriaxone and cefotaxime resistance were co-transferred on a 3.2-kb plasmid to the E. coli recipient strain. Loss of the 3.2-kb plasmid from the transconjugant resulted in the co-loss of ceftriaxone and cefotaxime resistance confirming the carriage of ceftriazone resistance on the 3.2-kb plasmid. CONCLUSION: Plasmid-mediated high-level resistance to ceftriaxone and ESBL production in Salmonella serotype typhimurium is an emerging problem among Salmonella that requires closer monitoring of antimicrobial resistance among these bacterial species.

Incidence of bloodstream infections in a speciality hospital in Kuwait: 8-year experience.

OBJECTIVES: To determine the frequency of isolation and antibiotic-susceptibility patterns of clinically significant bacterial pathogens isolated from blood. MATERIALS AND METHODS: The study was conducted over a period of 8 years (1995-2002) at Infectious Diseases Hospital (IDH), Kuwait. Demographic and clinical data were obtained from medical records. 18,535 blood cultures were analyzed. Disk diffusion method was used to perform antibiotic-susceptibility testing. Minimum inhibitory concentrations of 9 antimicrobials were determined using E-test. Double disk (potentiation) test and E-test ESBL strips were used to detect the production of extended-spectrum beta-lactamases (ESBLs). RESULTS: Salmonella spp. and Brucella spp. were predominant blood isolates, and represented 60.6 and 30.0% of all clinically significant episodes of bloodstream infections, respectively. Among the Salmonella, Salmonella enterica serotypes typhi and paratyphi A were most frequently isolated. The percentage of multidrug resistance (MDR) among them varied from 22 to 51%. A high percentage (40%) of MDR S. enterica serotypes typhi and paratyphi A also showed reduced susceptibility to ceftriaxone and ciprofloxacin. CONCLUSION: During the study period, Salmonella spp. and Brucella spp. were predominant blood isolates. MDR S. enterica serotypes typhi and paratyphi A, with reduced susceptibility to ceftriaxone and ciprofloxacin, are among the most frequent causes of bloodstream infections in IDH, suggesting the need to monitor their susceptibility.

Etiology and antibiotic susceptibility patterns of community-acquired urinary tract infections in a Kuwait hospital.

OBJECTIVE: The aim of this study was to determine the distribution and antibiotic susceptibility patterns of bacterial strains isolated from patients with community-acquired urinary tract infections (UTIs) at the Infectious Diseases Hospital, Kuwait. MATERIALS AND METHODS: The study was conducted over a 7-year period. Patient information was obtained from medical record files. Antibiotic-sensitivity testing was performed by disk diffusion. E test and double disk diffusion methods were used to study the production of extended spectrum beta-lactamases. RESULTS: Of the 14,042 urine samples processed, significant bacteriuria (>10(5) cfu/ml) was detected in 1,606 (11.4%). The majority (74.5%) of the isolates were from women while the remaining 25.5% were from men. The majority of infections (75%) were due to Enterobacteriaceae, coagulase-negative staphylococci (10.3%) and group B streptococci (8.7%). Among the gram-negative enteric bacilli high prevalence of resistance to ampicillin, amoxicillin/clavulanic acid, cephalothin, and trimethoprim/sulfamethoxazole was observed. Increasing resistance to ciprofloxacin and gentamicin was observed in E. coli isolates over the 7 years. Multiple resistance was detected in 53.8 and 41% of E. coli and Klebsiella spp. strains, respectively. No glycopeptide-resistant enterococci were isolated. CONCLUSION: This study revealed that Enterobacteriaceae were the predominant bacterial pathogen of community-acquired UTIs in Infectious Diseases Hospital, Kuwait. It also demonstrated an increasing resistance to ciprofloxacin, gentamicin and the production of extended spectrum beta-lactamase among UTI pathogens in the community.

MDR1 haplotypes modify BEN disease risk: a study in Bulgarian patients with Balkan endemic nephropathy compared to healthy controls.

BACKGROUND: Balkan endemic nephropathy (BEN) is a slow progressive nephropathy with frequent occurrence of uroepithelial tumors in the upper urinary tract. Genetic factors involved in xenobiotic detoxification mechanisms may cause genetic predisposition to BEN and influence the risk for this disease. Polymorphic MDR1 variants with decreased P-glycoprotein (P-gp) activity modulate the risk for renal neoplasm. We have therefore investigated the impact of MDR1 polymorphisms on BEN manifestation. METHODS: The constitutional genotype frequencies of two SNPs (C3435T and G2677T) in the MDR1 gene in 112 healthy control subjects were investigated and compared with those of 96 patients with BEN. Identification of the SNPs was done with rapid cycle real-time PCR and melting curve analysis with allele-specific probes. RESULTS: The frequency of mutant alleles was comparable in both groups. Significant differences were revealed when the MDR1 haplotypes were analyzed. Individuals with a predicted haplotype 12 (2677G/3435T) were less frequent in BEN cases (frequency 7.3%) than in controls (16.1%, p = 0.006). We found that carriers of the haplotype 12 had a decreased risk for BEN (OR = 0.411; 0.21-0.78). CONCLUSIONS: The data suggest that haplotype 12 is protective against BEN. There is no clear molecular explanation of the MDR1 haplotype effects on the protein activity, which can explain the modified effect of the haplotype 12 on BEN risk.

Antimicrobial susceptibility, phage typing and plasmid profile of Salmonella enterica serotype paratyphi A strains isolated in Kuwait.

OBJECTIVE: To determine the antimicrobial susceptibility, phage type and plasmid profile pattern of Salmonella enterica serotype paratyphi A strains isolated in Kuwait. MATERIAL AND METHODS: From January 1995 to December 1999, 106 strains of S. enterica serotype paratyphi A isolated from an equal number of cases of enteric fever, attending the Infectious Disease and Mubarak Al-Kabeer Hospitals in Kuwait were investigated. The isolates were tested for antimicrobial susceptibility to 8 commonly used antimicrobial agents. Their phage type and plasmid profile patterns were determined using an international set of phages and Qiagen plasmid mini kit, respectively. RESULTS: All of the isolates were susceptible to ciprofloxacin, cefuroxime, ceftazidime, piperacillin and co-trimoxazole. One hundred isolates were susceptible to ampicillin, 99 to chloramphenicol and 98 to tetracycline. None of the isolates was multidrug resistant. Sixty-six percent of the isolates were phage type I, 27.4% phage type II and 6.6% were untypable. All phage type I and untypable strains had 3 plasmids of 2.2, 5 and 20 kb, whereas phage type II strains had only 1 plasmid of 20 kb. CONCLUSION: The findings indicate that while all of the isolates of the S. enterica serotype paratyphi A were susceptible to 4 of the drugs tested, some were resistant to ampicillin, chloramphenicol or tetracycline, thereby indicating the need for continued surveillance and monitoring of antimicrobial susceptibility of these isolates.

Central and peripheral dysregulation of melanin-concentrating hormone in obese Zucker rats.

Melanin concentrating hormone (MCH) is a peptide synthesized in the lateral hypothalamus which stimulates food ingestion and leptin secretion in rodents. In this experiment, we measured the expressions of MCH as well as of its receptor (SLC-1) in the hypothalamus of obese hyperphagic and lean Zucker rats by quantitative real time RT-PCR. MCH mRNA expression in the obese rats was significantly increased by a factor of five (P<0.01) whereas expression of SLC-1 was decreased by more than 50% (P<0.05). Circulating levels of leptin and MCH were increased in the plasma of obese Zucker rats when compared to lean rats (38-fold and 1.7-fold, respectively, P<0.001 and P<0.01). However, individual MCH levels were not directly correlated to leptin levels in the lean (functional leptin receptor) or in the obese (non-functional leptin receptor) Zucker rats. These results indicate that the absence of leptin signaling in rats is associated with an increased hypothalamic expression and circulating release of MCH, contributing to their obesity syndrome.

Opposite regulation of hypothalamic orexin and neuropeptide Y receptors and peptide expressions in obese Zucker rats.

Many hyothalamic neuropeptides are involved in the regulation of food intake and body weight. The orexins (OX) which are synthesized in the lateral hypothalamus are among the most recently characterized whereas neuropeptide Y (NPY) belongs to a group of "older" peptides extensively studied for their effects on feeding behavior. Both stimulate food ingestion in rodents. In this experiment, we measured the expressions of these peptides as well as of their receptors (OX1-R and OX2-R, Y1 and Y5) in the hypothalamus of obese hyperphagic and lean Zucker rats by real-time RT-PCR using the TaqMan apparatus. NPY mRNA expression in the obese rats was significantly increased by a factor of 10 (P < 0.002) whereas expressions of the Y1 and Y5 receptors were decreased by 25% (P < 0.01) and 50% (P < 0.002), respectively. Their prepro-orexin mRNA expression was more than twofold decreased (P < 0.01) and expressions of their OX receptors 1 and 2 mRNA were five- and fourfold increased (P < 0.05), respectively. An inverse phenomenon was therefore noted between the two peptides: for NPY, increased levels and downregulation of receptors; and for OX, diminished levels with upregulation of receptors. The reasons for these changes might be linked to the absence of leptin signaling as similar profiles are found in the ob/ob mice. For orexins at least, other factors such as hyperglycemia might be involved. Based on anatomical considerations, a direct effect of NPY or of other brain peptides such as CRH cannot be excluded. We conclude that the diminution in the OX tone might participate in a counterregulatory system necessary to limit the noxious effects of NPY on food intake and body weight.

Pleiotrophin signals increased tyrosine phosphorylation of beta beta-catenin through inactivation of the intrinsic catalytic activity of the receptor-type protein tyrosine phosphatase beta/zeta.

Pleiotrophin (PTN) is a platelet-derived growth factor-inducible, 18-kDa heparin-binding cytokine that signals diverse phenotypes in normal and deregulated cellular growth and differentiation. To seek the mechanisms of PTN signaling, we studied the interactions of PTN with the receptor protein tyrosine phosphatase (RPTP) beta/zeta in U373-MG cells. Our results suggest that PTN is a natural ligand for RPTP beta/zeta. PTN signals through "ligand-dependent receptor inactivation" of RPTP beta/zeta and disrupts its normal roles in the regulation of steady-state tyrosine phosphorylation of downstream signaling molecules. We have found that PTN binds to and functionally inactivates the catalytic activity of RPTP beta/zeta. We also have found that an active site-containing domain of RPTP beta/zeta both binds beta-catenin and functionally reduces its levels of tyrosine phosphorylation when added to lysates of pervanidate-treated cells. In contrast, an (inactivating) active-site mutant of RPTP beta/zeta also binds beta-catenin but fails to reduce tyrosine phosphorylation of beta-catenin. Finally, in parallel to its ability to inactivate endogenous RPTP beta/zeta, PTN sharply increases tyrosine phosphorylation of beta-catenin in PTN-treated cells. The results suggest that in unstimulated cells, RPTP beta/zeta is intrinsically active and functions as an important regulator in the reciprocal control of the steady-state tyrosine phosphorylation levels of beta-catenin by tyrosine kinases and phosphatases. The results also suggest that RPTP beta/zeta is a functional receptor for PTN; PTN signals through ligand-dependent receptor inactivation of RPTP beta/zeta to increase levels of tyrosine phosphorylation of beta-catenin to initiate downstream signaling. PTN is the first natural ligand identified for any of the RPTP family; its identification provides a unique tool to pursue the novel signaling pathway activated by PTN and the relationship of PTN signaling with other pathways regulating beta-catenin.

Etiology of Balkan endemic nephropathy: a multifactorial disease?

Balkan endemic nephropathy (BEN) is of great clinical importance in the restricted areas of Bulgaria, Rumania, Croatia, Serbia, Bosnia and Herzegovina. So far, studies on the etiological factors for BEN have not discovered any single environmental causative agent of this puzzling disease. These data reject the possibility of a purely environmental causation of BEN. The pattern of BEN transmission in the risk families is not typical for single gene disorders. Extensive epidemiological and genetic studies disclose characteristics of multifactorial (polygenic) inheritance of BEN. The evidences of 'familial tendency', variation of the risk for BEN depending on the number of sick parents and the degree of relatedness; the development of BEN in individuals from at-risk families who were born in non-endemic areas; the data that disease is not found in the gypsy population and the expressions of 3q25 cytogenetic marker suggest that the genetic factors play an important role as causative factors in BEN development. The possible impact of environmental triggers on individuals genetically predisposed to BEN could be supposed by the following data: the cytogenetic results of the increased frequency of folate sensitive Fra sites, spontaneous or radiation-induced aberrations in several bands in BEN patients, the data from the detailed analysis of breaks in BEN patients and controls that generate structural chromosome aberrations; the occurrence of BEN in immigrants. Genetical epidemiological approaches to etiology and prevention of BEN are proposed. The predisposing genes for BEN could be genes localized in a region between 3q25-3q26; transforming growth factor-beta (TGF-beta), genetic heterogeneity of xenobiotic-metabolizing enzymes; defects in the host's immune system. The predisposing genes for BEN patients with urinary tract tumors could be germline mutations in tumor suppressor genes and acquired somatic mutations in oncogenes.