Isoproterenol and angiotensin I-converting enzyme in lung,left ventricle,and plasma during myocardial hypertrophy and fibrosis

This study investigated whether long-term administration of isoproterenol (ISO) induces differential expression of angiotensin-converting enzyme (ACE) in lung, plasma, and left ventricle (LV) during development of left ventricular hypertrophy (LVH) and myocardial fibrosis. Male Sprague-Dawley rats (n = 7-9 per group) were treated with isoproterenol (ISO) 5 mg/kg per day for 10 days or saline and examined at 1, 15, and 33 days after the last injection. ISO stimulated the development of left ventricular hypertrophy (LVH); relative LV weight (mg LV 100/body weight), LV protein content, and LV beta-myosin heavy chain levels increased at day 1. LVH regressed at days 15 and 33. ISO also increased myocardial fibrosis (assessed by hydroxyproline content and morphometry) at days 15 and 33. There no were changes in arterial blood pressure. Long-term beta-adrenergic stimulation with ISO increased ACE expression in lung, LV, and plasma during development of LVH and myocardial fibrosis. However, time courses were markedly different. ISO stimulated a sustained increase in lung and plasma ACE activities, whereas ISO induced a high LV ACE. Plasma ACE activity paralleled lung ACE activity. LV ACE activity correlated with ACE mRNA levels and paralleled development of LVH. Our data suggest long-term beta-adrenergic stimulation induced a differential temporal expression of LV, lung, and plasma ACE in rat during development of LVH and myocardial fibrosis.     

Insight on ALPPS – Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy – mechanisms: activation of mTOR pathway

Background

ALPPS procedure has been introduced to increase the volume of future liver remnant. The mechanisms underlying the accelerated regeneration observed with ALPPS are unknown. It was hypothesized that AMPK/mTOR is activated as an integrating pathway for metabolic signals leading to proliferation and cell growth. Our aim was to analyze increase in liver volume, proliferation parameters and expression of AMPK/mTOR pathway-related molecules in patients undergoing ALPPS.

PISCOM: a new procedure for epilepsy combining ictal SPECT and interictal PET

Purpose

We present a modified version of the SISCOM procedure that uses interictal PET instead of interictal SPECT for seizure onset zone localization. We called this new nuclear imaging processing technique PISCOM (PET interictal subtracted ictal SPECT coregistered with MRI).

Methods

We retrospectively studied 23 patients (age range 4–61 years) with medically refractory epilepsy who had undergone MRI, ictal SPECT, interictal SPECT and interictal FDG PET and who had been seizure-free for at least 2 years after surgical treatment. FDG PET images were reprocessed (rFDG PET) to assimilate SPECT features for image subtraction. Interictal SPECT and rFDG PET were compared using statistical parametric mapping (SPM). PISCOM and SISCOM images were evaluated visually and using an automated volume of interest-based analysis. The results of the two studies were compared with each other and with the known surgical resection site.

Results

SPM showed no significant differences in cortical activity between SPECT and rFDG PET images. PISCOM and SISCOM showed equivalent results in 17 of 23 patients (74%). The seizure onset zone was successfully identified in 19 patients (83%) by PISCOM and in 17 (74%) by SISCOM: in 15 patients (65%) the two techniques showed concordant successful results. The volume of interest-based analysis showed no significant differences between PISCOM and SISCOM in identifying the extension of the seizure onset zone. However, PISCOM showed a lower amount of indeterminate activity due to propagation, background or artefacts.

Conclusion

Preliminary findings of this initial proof-of-concept study suggest that perfusion and glucose metabolism in the cerebral cortex can be correlated and that PISCOM may be a valid technique for identification of the seizure onset zone. However, further studies are needed to validate these results.

     

Realización de procedimientos bariátricos por residentes de cirugía general. ¿Compromete la efectividad de la intervención y los resultados postoperatorios?

IntroductionLaparoscopic bariatric procedures such as laparoscopic Roux-en-Y gastric bypass (LRYGB) are technically demanding and require a long learning curve. Little is known about whether surgical resident (SR) training programs to perform these procedures are safe and feasible. This study aims to evaluate the results of our SR training program to perform LRYGB.MethodsWe designed a retrospective study including patients with LRYGB between January 2014 and December 2018, comparing SR results to experienced bariatric surgeons (EBS). In our country, SR have a five-year surgical formative period, and in the fourth year they are trained for 6 months in our bariatric surgery unit, from January to June. In the beginning, they perform different steps of this procedure, to finally complete an LRYGB. We collected demographic data, comorbidities, intraoperative outcomes, and postoperative complications and outcomes after a one-year follow-up.ResultsTwo hundred and eight patients were eligible for inclusion: 67 in group I (SR), and 141 in group II (EBS). Both groups were comparable. There was no statistically significant difference in operating time (166.45 min in group I vs. 156.69 min in group II; P=0.156). Conversion to open surgery, hospital stay, postoperative complications, and short-term outcomes had no significant differences between the two groups. There was no mortality registered during this period.ConclusionImplementation of LRYGB stepwise learning as part of an SR training program is safe, and results are comparable to EBS, without loss of efficiency. Therefore, it is feasible to train SR in bariatric surgery under EBS supervision.     

Atmospheric Spray Freeze-Drying: Numerical Modeling and Comparison With Experimental Measurements

Atmospheric spray freeze-drying (ASFD) represents a novel approach to dry thermosensitive solutions via sublimation. Tests conducted with a second-generation ASFD equipment, developed for pharmaceutical applications, have focused initially on producing a light, fine, high-grade powder consistently and reliably. To better understand the heat and mass transfer physics and drying dynamics taking place within the ASFD chamber, 3 analytical models describing the key processes are developed and validated. First, by coupling the dynamics and heat transfer of single droplets sprayed into the chamber, the velocity, temperature, and phase change evolutions of these droplets are estimated for actual operational conditions. This model reveals that, under typical operational conditions, the sprayed droplets require less than 100 ms to freeze. Second, because understanding the heat transfer throughout the entire freeze-drying process is so important, a theoretical model is proposed to predict the time evolution of the chamber gas temperature. Finally, a drying model, calibrated with hygrometer measurements, is used to estimate the total time required to achieve a predefined final moisture content. Results from these models are compared with experimental data.     

Conventional slow freezing cryopreserves mouflon spermatozoa better than vitrification

This work examines the effectiveness of a TCG (Tris, citric acid, glucose, 6% egg yolk and 5% glycerol) and a TEST (TES, Tris, glucose, 6% egg yolk and 5% glycerol) sperm extender in the freezing of mouflon spermatozoa at slow cooling rates, using different pre‐freezing equilibration times (2–3 hr). It also examines the tolerance of mouflon spermatozoa to different concentrations of cryoprotectants (5, 10, 20% glycerol; 5%, 10%, 20% dimethyl sulfoxide; 6% polyvinylpyrrolidone) and/or sucrose (100, 300, 500 mm ). The highest quality (p < .01) thawed spermatozoa were obtained when using the TEST extender and an equilibration time of 3 hr. Sperm motility and membrane integrity were strongly reduced when using rapid freezing rates (60–85°C min^?1), independent of the concentration of cryoprotectants. The lowest sucrose concentration (100 mm ) provided the highest (p < .05) percentage of motile spermatozoa and live spermatozoa with an intact acrosome. Vitrified–warmed sperm variables were at their best when the spermatozoa was diluted in TCG–6% egg yolk + 100 mm sucrose and warmed at 60°C. Slow warming at 37°C strongly reduced (p < .05) sperm motility and viability. However, sperm vitrification returned lower fertility, sperm motility and sperm viability values than conventional sperm freezing.     

Modification of adenosine modulation of synaptic transmission in the hippocampus of aged rats

We compared the modulation of synaptic transmission by adenosine A(1) receptors in the hippocampus of aged (24 months) and young adult rats (6 weeks). The adenosine A(1) receptor agonist, N(6)-cyclopentyladenosine, was less potent (P:<0.05) to inhibit synaptic transmission in aged (EC(50)=53 nM) than young adult (EC(50)=14 nM) hippocampal slices, these effects being prevented by the A(1) receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX). In contrast with the lower effect of the A(1) receptor agonist, it was observed that blockade of A(1) receptors with DPCPX (50 nM), or removal of endogenous extracellular adenosine with adenosine deaminase (2 u ml(-1)), caused a more pronounced disinhibition of synaptic transmission in aged rats. Also consistent with a more intense A(1) receptor-mediated inhibitory tonus by endogenous adenosine in aged rats was the finding that to fully prevent the depression of synaptic transmission induced by 3 min hypoxia, a higher concentration of DPCPX was required in slices from aged (100 nM) than from young (50 nM) rats. It is concluded that in hippocampal slices of aged rats the efficiency of A(1) receptors to modulate synaptic transmission is reduced, but this may be compensated by an enhanced inhibitory tonus by endogenous adenosine.