Plasma Calcitonin Levels and miRNA323 Expression in Medullary Thyroid Carcinoma Patients with or without RET Mutation

Background: Medullary thyroid cancer (MTC) is an endocrine tumor featuring parafollicular or C-cell differentiation, with calcitonin as a specific biomarker in MTC diagnosis. Germline mutations in the RET proto-oncogene are considered responsible for its familial occurrence and somatic mutations can cause sporadic lesions. MicroRNAs can act as oncogenes or tumor suppressors by inhibiting the expression of target genes.. The aim of this study was to investigate relationships between plasma levels of calcitonin and miRNA323 expression in MTC patients with or without RET mutation. Methods: In this cross-sectional study, MTC lesions (based on pathological confirmation) were investigated. Genomic DNA was extracted and Exons 10 and 11 of RET were genotyped using PCR-sequencing. Division was into two groups of 43 cases each with or without mutation. Plasma levels of calcitonin were determined in both. Results: miRNA323 was measured using real-time-PCR. After performing normality tests, independent T-tests and Mann Whitney tests were used for the statistical comparison of parametric and nonparametric data, respectively. Plasma levels of calcitonin were significantly higher in MTC cases without a RET mutation compared to those with a mutation. Conclusion: There was no significant difference between the two groups regarding the expression of miRNA323 so that this parameter could not be used as a bio-index germ line mutations in MTCs. However, determination of calcitonin levels in plasma might be helpful in this regard.     

Left atrium in cardiac resynchronization therapy: Active participant or innocent bystander

Background

Cardiac resynchronization therapy (CRT) is an established treatment for patients with advanced heart failure that results in improvement of left ventricle (LV) systolic function and LV reverse remodeling. This may have a positive effect on the size and the function of the left atrium (LA). We assessed the LA function, dimensions, and volumes before and after CRT implantation.

Calcium receptor message, expression and function decrease in differentiating keratinocytes

Calcium-sensing receptor (CaSR) expression and function were studied in proliferating and differentiating cultured human gingival keratinocytes (HGKs). CaSR mRNA and protein were present in proliferating HGKs cultured in 0.03 mM [Ca²⁺] and decreased in cells induced to differentiate by culturing in 1.2 mM [Ca²⁺] for 2 days. CaSR protein was also detected in gingival tissue. Exposure to 10 mM extracellular [Ca²⁺] activated two sequential whole-cell currents. The first was a small, transient calcium release activated calcium current I_CRAC-like current with an inwardly rectifying I-V curve. The second current was larger with a linear I-V curve. Both currents were significantly decreased in differentiating cells. Neither neomycin nor gadolinium induced changes in whole cell currents nor in intracellular [Ca²⁺], but neomycin inhibited the late large current. Extracellular Ca²⁺ increased intracellular [Ca²⁺] of proliferating HGKs in a dose-dependent fashion. Comparison of the time-courses of the whole-cell currents and the intracellular [Ca²⁺] responses indicated both induced currents supported a Ca²⁺ influx. Extracellular [Mg²⁺] changes did not affect intracellular [Ca²⁺]. La³⁺ and 2-APB inhibited the whole cell current and intracellular [Ca²⁺] changes. The results indicate that the CaSR signaling response likely plays a major role in initiating Ca²⁺ induced differentiation responses in HGKs.     

The effect of a selective 5-lipoxygenase inhibitor,zileuton, on tissue damage in acute colonic inflammation in rats

Though the mechanism of tissue damage induced by colonic inflammation in ulcerative colitis is unknown, it has been established that the inflammatory mediator and potent neutrophil (PMN) chemotaxin, leukotriene B4(LTB₄), is present in elevated amounts in the inflamed mucosa. The unique role of 5-lipoxygenase in the production of leukotrienes has made it a target for inhibition. This study used a rat model of acute colonic inflammation induced by a single IP injection of Mitomycin-C to test the efficacy of a specific and potent 5-lipoxygenase inhibitor zileuton in the treatment of colonic inflammation. We hypothesized that after inducing colitis in rats with mitomycin-C, the administration of oral zileuton would inhibit leukotriene production, thus preventing PMN infiltration and subsequent tissue damage. Zileuton decreased colonic tissue damage as measured by Histological score. However, zileuton did not significantly decrease neutrophil infiltration measured by mucosal PMN or myeloperoxidase (MPO) levels. Although zileuton was successful in significantly decreasing the frequency of severe colitis in our model, the fact that the decrease in PMN count and MPO level was not statistically significant suggests that another mechanism may be involved in its anti-inflammatory effect.     

Inaccuracy of clinical phenotyping parameters for hypertensive nephrosclerosis.

BACKGROUND: Multiple studies suggest that hypertension-induced end-stage renal disease (ESRD) is heritable. Identification of nephropathy susceptibility genes absolutely requires accurate phenotyping, but the clinical hypertensive nephrosclerosis (HN) phenotype is poorly characterized. We hypothesized that many patients with HN as the indicated cause of ESRD on the Health Care Financing Administration (HCFA) 2728 form, fail to satisfy stringent HN phenotyping criteria. METHODS: Since renal biopsy documentation of HN is uncommon, clinical parameters for HN phenotype were applied: family history of hypertension, left ventricular hypertrophy, proteinuria <0.5 g/day, and hypertension preceding renal dysfunction (Schlessinger et al., 1994) or urine protein:creatinine (prot:creat) ratio <2.0 and no evidence of other renal diseases (AASK Trial Group, 1997). RESULTS: ESRD patients (n=607, 73% African American, 25% Caucasian) were enrolled in a study to identify HN susceptibility genes. HN was the most common cause of ESRD according to HCFA 2728 forms (37% prevalence). Phenotyping of randomly selected patients with HN from the total cohort revealed that 4/100 subjects satisfied the Schlessinger criteria, and 28/91 African Americans met AASK criteria for HN. From these figures, the adjusted prevalence of HN was only 1.5-13.5%. Of patients that could not be phenotyped for HN, 14 were misdiagnosed, 14 had urine prot:creat >2.0, and insufficient data were available in the remainder. Four patients underwent renal biopsy, but histology from only one was consistent with HN. If the HN phenotype definitions are revised to exclude 'hypertension preceding renal dysfunction', or proteinuria limits, then 44/100 and 39/91 patients respectively satisfy clinical phenotyping parameters for HN. CONCLUSIONS: (i) We provide the strongest evidence to date that HN is less frequent in an ESRD population than commonly assumed if strict clinical criteria are used; many patients clinically diagnosed with HN may have undetected, treatable renal disease from other causes; (ii) relaxing HN phenotype criteria may erroneously include patients with glomerular diseases and secondary hypertension; (iii) reliance on HCFA 2728 diagnoses will confound identification of HN susceptibility genes; (iv) to attain adequate statistical power for genotype analysis, rigorous HN phenotyping will require screening an extremely large number of patients, which can be reasonably accomplished only in a multi-centre trial design.     

Efficacy of orally delivered cochleates containing amphotericin B in a murine model of aspergillosis

Cochleates containing amphotericin B (CAMB) were administered orally at doses ranging from 0 to 40 mg/kg of body weight/day for 14 days in a murine model of systemic aspergillosis. The administration of oral doses of CAMB (20 and 40 mg/kg/day) resulted in a survival rate of 70% and a reduction in colony counts of more than 2 logs in lungs, livers, and kidneys. Orally administered CAMB shows promise for the treatment of aspergillosis.     

Acetylcholine receptors and nerve terminal distribution at the neuromuscular junction of long-term regenerated muscle fibers

Mdx mice are deficient in dystrophin and show muscle fiber regeneration. Changes in the distribution of acetylcholine receptors have been reported at the neuromuscular junction of mdx mice and may be a consequence of muscle fiber regeneration. In this study, we examined whether the distribution of receptors was still altered in long-term, regenerated muscle fibers from C57Bl/10 mice. The left sternomastoid muscle of adult mice was injected with 60 μl of lidocaine hydrochloride to induce muscle degeneration-regeneration. In some mice, the sternomastoid muscle was denervated at the time of lidocaine injection. After 90 and 150 days, the nicotinic acetylcholine receptors were labeled with rhodamine-α-bungarotoxin for confocal microscopy. At both intervals studied, the receptors were distributed in spots. In denervated-regenerated fibers, the receptors were distributed as regular branches similar to denervated muscles without lidocaine treatment. These findings suggested that nerve-dependent mechanisms were involved in the changes in receptor distribution seen in regenerated muscle fibers after lidocaine treatment, and that a similar phenomenon could explain the changes in receptor distribution seen in dystrophic muscle fibers.     

Insulin and growth-hormone responses in neonatal hyperglycemia.

Glucose, insulin, and growth hormone values were studied prospectively in 75 premature infants during the first five days after birth. Intravenous glucose was given at a mean rate of 4.7-4.9 mg./kg./min. (range 3-7). Mean birth weight was 1,394+/-47 gm. (mean+/-S.E.M.). Blood glucose values were significantly higher on days 1 and 2 than on days 3 to 5. Hypoglycemia (blood glucose less than 20 mg./100 ml.) occurred in two SGA and one AGA infants. On the other hand, hyperglycemia (greater than 125 mg./100 ml.) was found in 32 of the 75 (42.7 per cent) infants. A significantly greater number of deaths occurred in infants with hyperglycemia (19/32) than in those with normoglycemia (19/32) than in those with normoglycemia (5/43). Mean plasma insulin values were significantly higher on days 1 and 2 (15+/-3 and 18+/-4 muU./ml.) than on days 3 and 4-5 (6+/-1 and 7+/-2 muU./ml.). In addition, mean insulin levels were significantly higher during hyperglycemic than during normoglycemic glucose levels at similar postnatal age. Growth hormone values were higher during the first three days than subsequently, but the values were similar in normoglycemic and hyperglycemic groups. Significant negative correlations were seen between glucose values on the first two days of postnatal life and birth weight, gestational age, and Apgar scores, whereas positive correlations were found with FiO2 and respiratory distress score (RDS).