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).     

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.     

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.     

CDH1 germline variants are enriched in patients with colorectal cancer,gastric cancer,and breast cancer

Background and aims CDH1 germline variants have been linked to heritability in diffuse gastric (DGC) and lobular breast cancer (LBC). Studies have not yet assessed whether CDH1 is a cancer-susceptibility gene in other cancers. Herein, we mapped the landscape of pathogenic and likely pathogenic (P/LP) germline variants in CDH1 across various cancers and ethnicities.Methods We evaluated CDH1 germline P/LP variants in 212,944 patients at one CLIA-certified laboratory (Invitae) and described their frequency in 7 cancer types. We screened for CDH1 variant enrichment in each cancer relative to a cancer-free population from The Genome Aggregation Database version 3 (gnomADv3).Results CDH1 P/LP variants were identified in 141 patients, most commonly in patients with DGC (27/408, 6.6%) followed by colorectal signet-ring cell cancer (CSRCC; 3/79, 3.8%), gastric cancer (56/2756, 2%), and LBC (22/6809, 0.3%). CDH1 P/LP variants were enriched in specific ethnic populations with breast cancer, gastric cancer, CRC, LBC, DGC, and CSRCC compared to matched ethnicities from gnomADv3.Conclusion We report for the first time the prevalence of P/LP CDH1 variants across several cancers and show significant enrichment in CDH1 P/LP variants for patients with CSRCC, DGC, and LBC across various ethnicities. Future prospective studies are warranted to validate these findings.Subject terms: Cancer genomics, Genetics research     

l-carnitine modulates free mitochondrial DNA DAMPs and platelet storage lesions during storage of platelet concentrates

Journal of Thrombosis and Thrombolysis - Platelet storage lesions may occur in Platelet concentrates (PCs) storage time, reducing PCs' quality. Mitochondrial damage causes mitochondrial DNA...