Are there gender differences in left ventricular remodeling after myocardial infarction in rats?

Objective

An unclear issue is whether gender may influence at cardiac remodeling after myocardial infarction (MI). We evaluated left ventricle remodeling in female and male rats post-MI.

Methods

Rats were submitted to anterior descending coronary occlusion. Echocardiographic evaluations were performed on the first and sixth week post-occlusion to determine myocardial infarction size and left ventricle systolic function (FAC, fractional area change). Pulsed Doppler was applied to analyze left ventricle diastolic function using the following parameters: E wave, A wave, E/A ratio. Two-way ANOVA was applied for comparisons, complemented by the Bonferroni test. A P≤=0.05 was considered significant.

Results

There were no significant differences between genders for morphometric parameters on first (MI [Female (FE): 44.0±5.0 vs. Male (MA): 42.0±3.0%]; diastolic [FE: 0.04±0.003 vs. MA: 0.037±0.005, mm/g] and systolic [FE: 0.03±0.0004 vs. MA: 0.028±0.005, mm/g] diameters of left ventricle) and sixth (MI [FE: 44.0±5.0 vs. MA: 42.0±3.0, %]; diastolic [FE: 0.043±0.01 vs. MA: 0.034±0.005, mm/g] and systolic [FE: 0.035±0.01 vs. MA: 0.027±0.005, mm/g] of LV) week. Similar findings were reported for left ventricle functional parameters on first (FAC [FE: 34.0±6.0 vs. MA: 32.0±4.0, %]; wave E [FE: 70.0±18.0 vs. MA: 73.0±14.0, cm/s]; wave A [FE: 20.0±12.0 vs. MA: 28.0±13.0, cm/s]; E/A [FE: 4.9±3.4 vs. MA: 3.3±1.8]) and sixth (FAC [FE: 29.0±7.0 vs. MA: 31.0±7.0, %]; wave E [FE: 85.0±18.0 vs. MA: 87.0±20.0, cm/s]; wave A [FE: 20.0±11.0 vs. MA: 28.0±17.0, cm/s]; E/A [FE: 6.2±4.0 vs. MA: 4.6±3.4]) week.

Conclusion

Gender does not influence left ventricle remodeling post-MI in rats.     

Cerebrospinal Fluid Aβ42 Levels: When Physiological Become Pathological State

Impaired amyloid beta (Aβ) metabolism is currently considered central to understand the pathophysiology of Alzheimer's disease (AD). Measurements of cerebrospinal fluid Aβ levels remain the most useful marker for diagnostic purposes and to individuate people at risk for AD. Despite recent advances criticized the direct role in neurodegeneration of cortical neurons, Aβ is considered responsible for synaptopathy and impairment of neurotransmission and therefore remains the major trigger of AD and future pharmacological treatment remain Aβ oriented. However, experimental and clinical findings showed that Aβ peptides could have a wider range of action responsible for cell dysfunction and for appearance of clinico‐pathological entities different from AD. Such findings may induce misunderstanding of the real role played by Aβ in AD and therefore strengthen criticism on its centrality and need for CSF measurements. Aim of this review is to discuss the role of CSF Aβ levels in light of experimental, clinical pathologic, and electrophysiological results in AD and other pathological entities to put in a correct frame the value of Aβ changes.     

Effect of postural angle on back muscle activities in aging female workers performing computer tasks

[Purpose] This study investigated the effects of postural angle on back muscle activity during a computer task in aging women. [Subjects] Seventeen women ≥50 years old participated. [Methods] The participants were instructed to perform computer-related tasks for 20 minutes on a workstation that simulated typical office working conditions. Back posture was measured from the measured trunk and pelvic angles. Electromyography activities were recorded simultaneously from the cervical erector spinae, longissimus, and multifidus muscles. [Results] The lowest mean percentages of maximum voluntary contraction for the cervical erector spinae and longissimus muscles were obtained when the upper trunk and pelvic angles were between 0° to −5° from the sagittal plane. The back muscle activities increased as the upper trunk and pelvic angles exceeded 0°. Statistical analysis showed significant correlations between upper trunk angle and cervical erector spinae and longissimus muscle activities. Similarly, pelvic angle was significantly correlated with cervical erector spinae and multifidus muscle activities. [Conclusion] A neutral back posture minimizes muscle activities in aging women performing computer tasks.Key words: Postural angle, Muscle activity, Aging     

Effect of tetanus toxin on the accumulation of the permeant lipophilic cation tetraphenylphosphonium by guinea pig brain synaptosomes

Accumulation of the permeant lipophilic cation [(3)H]tetraphenylphosphonium (TPP(+)) by synaptosome preparations from guinea pig brain cerebral cortex is inhibited 1:10 by medium containing 193 mM K(+) and by veratridine. A further 1:10 to 1:15 decrease in TPP(+) uptake occurs under nitrogen and in the presence of mitochondrial inhibitors such as oligomycin, whereas starvation and succinate supplementation have no effect. These data indicate that, in analogy to intact neurons, there is an electrical potential (DeltaPsi, interior negative) of -60 to -80 mV across the synaptosomal membrane that is due primarily to a K(+) diffusion gradient (K(+) (in)-->K(+) (out)). The data also indicate that mitochondria entrapped within the synaptosome but not free mitochondria make a large contribution to the TPP(+) concentration gradients observed.Conditions are defined in which tetanus toxin binds specifically and immediately to synaptosomes in media used to measure TPP(+) uptake. Under these conditions tetanus toxin induces dose-dependent changes in TPP(+) uptake that are blocked by antitoxin and not mimicked by biologically inactivated toxin preparations. The effect of tetanus toxin on TPP(+) uptake is not evident in the presence of 193 mM K(+) or veratridine but remains under conditions known to abolish the mitochondrial DeltaPsi. Moreover, tetanus toxin has no effect on TPP(+) uptake by isolated synaptosomal mitochondria. The results thus define an in vitro action of tetanus toxin on the synaptosomal membrane that can be correlated with biological potency in vivo and is consistent with the in vivo effects of tetanus toxin on neuronal transmission.     

Dipeptidyl peptidase-4 expression in pancreatic tissue from patients with congenital hyperinsulinism

Congenital hyperinsulinism (CHI) is caused by unregulated insulin release and leads to hyperinsulinaemic-hypoglycaemia (HH). Glucagon like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), peptide YY (PYY) and the enzyme; dipeptidyl peptidase-4 (DPP-4) all regulate appetite and glucose homeostasis. These proteins have been identified as possible contributors to HH but the mechanism remains poorly understood. We aimed to look at the expression pattern of pancreatic DPP-4 in children with focal and diffuse CHI (FCHI and DCHI, respectively). Using immunohistochemistry; we determined DPP-4 expression patterns in the pancreas of CHI patients. DPP-4 was found to be expressed in the pancreatic β, α and δ-cells in and around the focal area. However, it was predominantly co-localised with β-cells in the paediatric tissue samples. Additionally, proliferating β-cells expressed DPP-4 in DCHI, which was absent in the FCHI pancreas. Insulin was found to be present in the exocrine acini and duct cells of the DCHI pancreas suggestive of exocrine to endocrine transdifferentiation. Furthermore, 6 medically-unresponsive DCHI pancreatic samples showed an up-regulation of total pancreatic DPP-4 expression. In conclusion; the expression studies have shown DPP-4 to be altered in HH, however, further work is required to understand the underlying role for this enzyme.