Structural basis for mechanical transduction in the frog vestibular sensory apparatus: III. The organization of the otoconial mass.

The saccule and the utricle of the vestibular system detect linear acceleration and gravity. Sensory transduction in these organs depends on myriads of calcium carbonate crystals of high specific gravity, called otoconia, embedded in a filament matrix that overlies the sensory epithelium. The coexistence of hard crystals and slender filaments in this complex extracellular matrix makes it difficult to analyze by conventional electron microscopy. We have now examined this structure in the bullfrog saccule using the quick-freeze, deep-etch replica technique. The otoconia in their typical aragonite polymorph shape exhibit smooth surfaces and are embedded in a loose matrix made of two types of filaments. The regular surface of the otoconia forms a natural smooth background against which we could observe with unprecedented detail the network organization and substructure of the filaments. One type of filament is 8 nm in diameter, while the other, which has a characteristic beaded appearance, is 15 nm in diameter. Both types of filaments either make lateral connections with or end directly on the surface of the otoconia. A consistent observation was the presence of short filaments that directly cross-link adjacent otoconia. Very few otoconia were fractured in an orientation that would allow the study of their internal architecture. These otoconia presented a typical conchoidal cleavage of aragonite. Although crystallites were not clearly apparent, thin lamellar microstructures appeared oriented both perpendicularly and longitudinally to the major otoconial axis. This structural study establishes a framework for the identification of the molecular components present in this unique extracellular matrix and may also help elucidate their role in mechanical transduction.     

The relation between the presence of a giant primary ovarian leiomyoma and the occurrence of epilepsy as a paraneoplastic syndrome

Introduction  

Primary ovarian leiomyoma is a quite rare tumor and usually it is small and unilateral. Most cases are asymptomatic. This benign tumor is usually diagnosed incidentally on routine pelvic examination or in pathologic specimens at surgery or at autopsy.     

Reanalysis of human blastocysts with different molecular genetic screening platforms reveals significant discordance in ploidy status

Objective

The objective of this study is to determine mosaicism and its effect on blastocysts; abnormal blastocysts determined by molecular testing were sequentially biopsied and retested.

Material and method

We re-biopsied 37 blastocyst-stage abnormal embryos from eight patients, which were reanalyzed to determine the level of concordance between biopsies and inter-laboratory congruence between reputable commercial PGS laboratories.

Results

The main outcome measures were intra-embryo variation between sequential embryo biopsies and inter-laboratory variation between two PGS laboratories. The compatibility between both aCGH and NGS was found to be 11 % (3/27). Importantly, 9/27 (33 %) of embryos originally reported to be aneuploid, upon repeat assessment, were found to be euploid. The concurrence for SNP array and NGS was 50 % (3/6), and 17 % (1/6) of these abnormal embryos tested normal upon re-evaluation with NGS. NGS resulted 41 % (11/27) normal results when 27 of CGH abnormal embryos were retested. Concordance between aCGH and NGS was 4 % (1/27) whereas in three instances, gender discrepancy was observed with NGS when aCGH abnormal embryos were reanalyzed.

Conclusions

The results of these studies reinforce the prevalence of inconsistencies during PGS evaluation of trophectoderm biopsies possibly due to variations in platform sensitivity and heightening concerns over the clinical tractability of such technology in human ARTs..

     

Assessment of molecular events in squamous and non-squamous cell lung carcinoma

Although considerable knowledge exists on the tumor biology of lung cancer, there is still a need to assess molecular events for the clinical management of the disease. We studied the pattern of chromosomal imbalances in 45 non-small cell lung carcinomas (NSCLC) by comparative genomic hybridization (CGH) and correlated the results with clinicopathological features including immunohistochemical (IHC) expression of the epidermal growth factor receptor (EGFR). Twenty-one tumors were squamous cell carcinomas (SCC) and 24 non-squamous cell lung carcinomas (NSCC) comprising 9 adenocarcinomas (ADC), 9 large cell carcinomas (LCC), 4 sarcomatoid carcinomas and 2 adenosquamous carcinomas. The mean number of individual imbalances was 7.1 for SCC (mean gains, 3.8; mean losses, 3.4) and 6.4 for NSCC (mean gains, 4.5; mean losses, 1.9). Several individual imbalances correlated significantly with increasing number of imbalances, that were +1q, -3p, +3q, -5q, -8p, +8q, +7p, +12p, and +14q. Altogether, the most frequent imbalances were +3q (49%), +5p (49%), -5q (36%), +8q (29%), -8p (24%), -3p (22%), +7p (22%), +12p (22%), +14q (20%), +18p (20%), +1q (18%), and +7q (18%). Among these, +3q and +18p correlated significantly with SCC, and +5p and +14q with NSCC. Remarkably, overlapping imbalances included +3q26, +7p11 in SCC and +1q21, +3q24, +12p11, and +14q12 in NSCC. EGFR expression was higher in SCC than in NSCC and correlated with +3q in the entire series. In addition, +12p correlated significantly with disease progress with the exception of nodal involvement in NSCC as well as with disease progress, regardless of nodal involvement, in the entire series. In conclusion, the present study contributes to the molecular biological characterization of NSCLC histological subtypes and through evaluation of molecular events to the recently emergent focus on novel markers for lung cancer treatment.     

GST (GSTM1, GSTT1, and GSTP1) polymorphisms in the genetic susceptibility of Turkish patients to cervical cancer

Objective

This work investigates the role of glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1), and glutathione S-transferase P1 (GSTP1) enzymes and polymorphisms, which are found in phase II detoxification reactions in the development of cervical cancer.

Methods

This study was conducted with 46 patients diagnosed with cervical cancer and 52 people with no cancer history. Multiplex PCR methods were used to evaluate the GSTM1 and GSTT1 gene polymorphism. However, the GSTP1 (Ile105Val) gene polymorphism was studied using a PCR-RFLP method. The patient and control groups were compared using a chi-square test with p<0.05.

Results

In the patient group, statistical significance was determined for gravidity (p=0.03), parity (p=0.01), and the number of living children (p=0.01) compared to the control group. The gene frequency of GSTM1, GSTT1, and GSTP1 polymorphisms was evaluated. We observed that GSTM1 and GSTT1 null genotype frequencies were 54.3% and 32.6% respectively, while GSTP1 (Ile/Val), (Ile/Ile), (Val/Val) genotype frequencies were 52%, 44%, and 4%, respectively, in the cervical cancer patients. No statistical variation was determined between the control and patient groups in terms of GSTM1, GSTT1, and GSTP1 polymorphisms (p>0.05).

Conclusion

Our results demonstrate that GSTT1, GSTM1, and GSTP1 polymorphisms are not associated with cervical cancer in Turkish patients.     

Anti-apoptotic effect of succinyl gelatine in a liver ischaemia-reperfusion injury model (Bcl-2, Bax, Caspase 3)?

Apoptosis of tissues may contribute to ischaemia-reperfusion injury. The aim of the present study was to determine whether administration of a colloid solution would prevent apoptosis after liver ischaemia-reperfusion. New Zealand rabbits, weighing 1.5-2 kg, were randomized to receive either 4% SG (20 ml kg (-1)h(-1) ) by 30 min of intravenous (i.v.) infusion (Group I, n= 7) or equivalent volumes of 0.9% sodium chloride (Group II, n= 6) i.v. before a 45 min interruption of the portal vein blood flow and then 45 min of reperfusion. The animals were killed following the reperfusion period. Their livers were processed for histopathological examination and paraffin sections of these tissues were examined. The expression of Bcl-2, Bax and caspase 3 were analysed by immunohistochemistry. ANOVA and the Wilcoxon W -test were used for statistical analysis, and mean values were expressed +/-sd. Histologically, the foci of ischaemic necrosis were observed in liver specimens of the periportal area in one of the animals in Group I and in two in Group II. Immunhistochemical analysis demonstrated an increase in Bcl-2 protein levels in Group I compared to Group II ( P< 0.05). Bax expression was lower in Group I than in Group II. Immunoreactivity for caspase 3 did not differ significantly between the two groups (47.0 +/- 35.93 in Group I, 32.83 +/- 23.63 in Group II). Our results indicate that gelofusine did not protect the liver tissue against ischaemia-reperfusion-induced apoptosis.     

PCNA and Ki-67 in Central Nervous System Tumors: Correlation with the Histological Type and Grade

Determination of proteins in the control of proliferation in normal cells helps a better understanding of cellular transformation and proliferation mechanisms. Measurement of proliferative activity is important in determining the tumor grade, recurrence span and malignancy. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two of the nuclear markers used to demonstrate the proliferative phase of the cell cycle.In the present study, 63 central nervous system (CNS) tumors of various histologic types, diagnosed in Çukurova University Medical Faculty, Department of Pathology and graded according to WHO grading system were examined for PCNA and Ki-67 monoclonal antibodies using immunohistochemistry. Results were analyzed with statistical methods. Distribution of PCNA and Ki-67 LI (labeling index) values were determined for different tumor types. The highest PCNA and Ki-67 LI values were detected in medulloblastoma, malignant meningioma, primitive neuroectodermal tumor (PNET) and glioblastoma (GBM) groups, while pilocytic astrocytoma, meningioma, craniopharyngioma and oligodendroglioma showed the lowest values.In such tumors, the correlation between the increasing grade and PCNA and Ki-67 LI values were statistically significant. A correlation between the clinical outcome and Ki-67 and PCNA LI values was also detected.Conclusively, both markers can be used to evaluate the tumor grade and to asses the possibility of recurrence and malignancy in CNS tumors.     

Exposure to the n-3 polyunsaturated fatty acid docosahexaenoic acid impairs α1-adrenoceptor-mediated contractile responses and inositol phosphate formation in rat cardiomyocytes

The beneficial effects of n-3 polyunsaturated fatty acids of fish oil in the prevention of fatal arrhythmias in myocardial ischemia were suggested to be at least in part mediated by a modulation of dihydropyridine-sensitive L-type calcium channels. As cardiac ₁-adrenoceptor stimulation has been suggested to have no significant effect on L-type calcium channels, the aim of this study using cultured neonatal rat cardiomyocytes was to investigate whether chronic n-3 polyunsaturated fatty acid exposure may have an influence on ₁-adrenoceptor-induced positive inotropic effects and induction of arrhythmias. Pretreatment of the rat cardiomyocytes for 3 days in the presence of the n-3 polyunsaturated fish oil-derived fatty acid docosahexaenoic acid (60 mol/l) markedly decreased ₁-adrenoceptor-stimulated increase in contraction velocity and induction of arrhythmias. The increase in contraction velocity of the cardiomyocytes induced by the -adrenoceptor agonist isoprenaline was also markedly reduced by the n-3 fatty acid pretreatment. Basal contractile amplitude and spontaneous beating frequency of the cardiomyocytes were not significantly altered by the docosahexaenoic acid exposure. The pretreatment of the rat cardiomyocytes for 3 days in the presence of docosahexaenoic acid (60 mol/l) decreased ₁-adrenoceptor-stimulated formation of the calcium-mobilizing second messenger IP₃ and its metabolites IP₂ and IP₁ by 55%. The depression of IP₃ formation by docosahexaenoic acid treatment was not mediated by a decreased uptake of myo-inositol into the cardiomyocytes nor by a decreased synthesis of phosphatidylinositol bisphosphate (PIP₂), the substrate of phospholipase C. The level of glycerol-3-phosphate, an important substrate of the phosphoinositide cycle, was unaltered by the docosahexaenoic acid pretreatment. Receptor binding studies revealed that the dissociation constant and maximal binding capacity of the ₁-adrenoceptor antagonist (³H)prazosin was unchanged by the n-3 polyunsaturated fatty acid exposure. -Adrenoceptor-and forskolin-stimulated adenylyl cyclase activities were not diminished by the docosahexaenoic acid pretreatment. Chronic exposure of the cardiomyocytes to the n-6 polyunsaturated fatty acid arachidonic acid (60 mol/l) did neither significantly alter ₁-adrenoceptor-induced inositol phosphate formation nor ₁-adrenoceptor-stimulated increase in contraction velocity. The results presented show that chronic n-3 polyunsaturated fatty acid pretreatment of rat cardiomyocytes leads to a marked impairment of ₁-adrenoceptor-induced positive inotropic effects and induction of arrhythmias concomitant with a n-3 fatty acid-induced decrease in IP₃ formation. This derangement of the phosphonositide pathway by chronic n-3 fatty acid exposure may, thus, contribute to the beneficial effects of fish oil-derived fatty acids in the prevention of fatal arrhythmias in myocardial ischemia.     

Atrial septal defect and retrosternal toxic goitre operated in the same session: a case report.

In this study, we present a 55-year-old female patient who suffered from atrial septal defect (ASD) and retrosternal toxic goitre simultaneously. The patient had been treated with a 300 mg/day dose of propylthiouracil for 20 days prior to operation. This patient has been operated on for both disorders and has recovered.