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Understanding the mechanisms that may lead to failure of rocking bodies is significantly important in quantifying and minimizing the associated risk. The most common model to describe the rocking problem is the inverted pendulum model (IPM) proposed by GeorgeW. Housner, which has been followed by multiple researchers. It is often claimed that the IPM is an acceptable model if behaviors such as sliding, uplifting, deformability, and the three-dimensional nature of the response can be restrained mechanically. However, even in a suitably chosen case in which the previous may indeed have a minimal effect in the response, there are still uncertainties with regard to the assumption introduced in the IPM of how energy is lost during impacts. This paper focuses on this assumption and investigates the effects in the stability of rocking bodies. The effect of this assumption is discussed, showing that the associated uncertainty points to whether a rocking body would survive or fail when subjected to a ground excitation. A method that quantifies this uncertainty by making use of a dynamic property of the rocking system is introduced. [ABSTRACT FROM AUTHOR]

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The article presents an abstract of the paper "Absolute Values for TCA Cycle Flux and Exchange of Glutamate, Glutamine, and GABA Between Neuronal and Glial Compartments of Adult Rat Brain During (1,2-13C2) Acetate Metabolism." The paper will be presented at the 30th meeting of the American Society for Neurochemistry. The meeting is scheduled to be held in New Orleans, Louisiana, from March 14-17, 1999. The paper describes the calculation of absolute values for glial tricarboxilic acid cycle.

Las vitaminas C y E se han suplementado por separado para mejorar la fertilidad en el ganado. El objetivo de este estudio fue evaluar el efecto de las inyecciones combinadas de dosis aumentadas de vitaminas C y E en parámetros reproductivos del ganado lechero. Las vacas lactantes Holstein (n= 44) se asignaron al azar a uno de tres tratamientos: 1) Testigo: n = 15, las vacas no fueron inyectadas con vitaminas; 2) VCE3: n= 15, recibieron una única inyección intramuscular de 3,000 UI de vitamina E antes del estro y múltiples inyecciones subcutáneas de vitamina C con una dosis total de 3,000 mg antes y después del estro; 3) VCE6: n= 14, las vacas se trataron como en VCE3, pero las dosis de vitaminas C y E se incrementaron a 6,000 mg y 6,000 UI. Los indicadores reproductivos medidos fueron el diámetro del folículo preovulatorio, el tiempo al celo, el área del cuerpo lúteo, la tasa de preñez 35 y 45 días después de la IA y las concentraciones plasmáticas de estradiol y progesterona. No hubo efecto del tratamiento en ninguno de los parámetros reproductivos evaluados (P>0.05), excepto que la dosis más baja de vitaminas mantuvo tasas de gestación similares entre los tratamientos, aunque tuvieron concentraciones de progesterona más bajas (P≤0.05) (19.4 ± 2.66 vs 10.1 ± 2.55 vs 19.2 ± 0.44 ng mL-1 para los grupos Testigo, VCE3 y VCE6, respectivamente). En conclusión, la suplementación con la mayor cantidad de vitamina C y E (6,000 mg y 6,000 UI frente a 3,000 mg y 3,000 UI) no aumenta significativamente los parámetros reproductivos medidos. [ABSTRACT FROM AUTHOR]

Introduction: A proportion of monochorionic diamniotic (MCDA) twin pregnancies complicated by twin-to-twin transfusion syndrome (TTTS) can present after 26 weeks of gestation. The aim of this study was to compare perinatal outcomes of late TTTS treated by fetoscopic laser coagulation versus traditional management with amniodrainage and/or emergency preterm cesarean delivery (CD)., Methods: Retrospective cohort from January 2012 to January 2023 of consecutive MCDA twin pregnancies complicated by TTTS after 26 weeks and evaluated in our referring centers. We analyzed perinatal outcomes of cases treated with fetoscopic laser surgery at our national referral fetal surgery center in Queretaro, Mexico, and compared them with those managed with traditional management (amniodrainage and/or emergency preterm CD). The primary outcome was survival at discharge and the secondary outcome was gestational age (GA) at birth., Results: Among the study population, 46 TTTS cases were treated by fetoscopy at 27+6 (26+0-31+0) weeks+days and were compared with a group of 39 cases who underwent emergency preterm CD. In comparison to the group who underwent traditional management, the group treated by laser fetoscopy showed a significantly higher GA at birth (32+3 vs. 29+1 weeks+days, p < 0.001), lower frequency of preterm delivery below 37 weeks (91.3% vs. 100%, p = 0.06), 34 weeks (63.0% vs. 100%, p < 0.001), 32 weeks (50% vs. 74.4%, p = 0.02), or 30 weeks (28.3% vs. 53.8%, p = 0.01), and significantly higher perinatal survival (89.1% vs. 71.8%, p < 0.05 of at least one twin; and 65.2% vs. 38.5%, p = 0.01 of both twins, respectively)., Conclusion: MCDA twins complicated with TTTS can be treated with fetoscopic laser surgery between 26 and 31 weeks of gestation, which is a feasible and safe option, and such cases are associated with a higher GA at birth and better perinatal survival than those managed with amniodrainage and/or emergency preterm CD., (© 2023 S. Karger AG, Basel.)

Objective: To determine the differences in the neutrophil/lymphocyte ratio (NLR) and the platelet/lymphocyte ratio (PLR) in pregnant women with and without COVID-19., Methods: Observational, cross-sectional, retrospective, comparative, open, controlled study done from January to April 2021 at the UMAE Hospital de Gineco Obstetricia "Luis Castelazo Ayala" Instituto Mexicano del Seguro Social. Mexico City, Mexico: Patients were divided into those with a negative test for COVID-19 and those with a positive test, with the latter then being divided according to disease severity into mild, moderate, and severe groups. In all the NLR and PLR were calculated. Symptoms, vital signs, and oxygen saturation were documented., Statistical Analysis: Central tendency and dispersion measures, Kruskal-Wallis test, Mann-Whitney U test, and chi-squared test were used. Sensitivity, specificity, positive predictive value, negative predictive value, and odds ratio (OR) were calculated., Results: Seventy-seven patients were included, 24 without COVID-19 and 53 with COVID-19. There were 33, 10, and 10 patients in the mild, moderate, and severe disease groups, respectively. There was no difference in NLR between the groups and the PLR was significantly higher in the severe disease group. With a 5.1 NLR cutoff point, between normal and those with severe disease, the sensitivity was 70% and specificity 63%, whilst with a 221 PLR cutoff point, the sensitivity was 90% and the specificity 83% (OR 45, 95% CI 4.40-461.7)., Conclusion: PLR more than NLR was useful to detect pregnant patients with COVID-19 with severe disease., (© 2021 International Federation of Gynecology and Obstetrics.)

Background: COVID-19 disease is the leading cause of maternal death in Mexico. The data published to date indicate that pregnancy favors severe forms of the disease., Objective: To describe the clinical, obstetric and perinatal characteristics of pregnant women with COVID-19 disease treated at the UMAE "Luis Castelazo Ayala" of the Instituto Mexicano del Seguro Social., Material and Methods: Observational, cross-sectional and retrospective study of pregnant women with COVID-19 treated from March to December 2020. The epidemiological characteristics, complications and perinatal results were analyzed with descriptive and inferential statistics., Results: 133 patients included: 84.5% with mild disease, 8 % moderate and 8.5% severe and critical. Pre-existing comorbidities: obesity, diabetes and hypothyroidism. Main symptoms: cough, headache, fever, rhinorrhea and anosmia. In severe and critical cases, tachycardia, tachypnea, and hypoxemia were present. Lymphoneutropenia, hyperglycemia, and transaminasemia were seen in severe and critical forms. Fibrinogen and D dimer stayed unchanged. Preterm delivery, oligohydramnios, gestational hypertension, severe preeclampsia, and pneumonia were the main complications. 75% of the newborns without complications., Conclusions: The clinical behavior of the disease was mostly mild and even in moderate cases, and even in moderate as well as severe and complicated cases, the binomial results were favorable. There was no maternal death., (© 2022 Revista Medica del Instituto Mexicano del Seguro Social.)

Introduction: In patients with COVID-19, olfactory dysfunction and anosmia have been reported, which in pregnant women occur in up to 24.2 %., Objective: To know the frequency at which pregnant women with SARS-CoV-2 infection have olfactory dysfunction., Methods: Age, gestational age, temperature, presence of nasal constipation or rhinorrhea, myalgia, headache, cough or chest pain were asked. Whether patients perceived and identified the scent of grape juice, coffee powder and menthol was evaluated. Central tendency and dispersion measures, frequencies and percentages were used. Sensitivity, specificity, positive and negative predictive value were calculated. Mann-Whitney's U-test and contrast of proportions were used for comparisons between groups., Results: There was a higher proportion of women with cough, headache, dyspnea, myalgia, odynophagia, rhinorrhea, chest pain, and anosmia in SARS-CoV-2-positive women. In patients without COVID-19, 88.9 % detected each one of the scents; only 31.8 % of the positive group detected grapes scent, 47.7 % coffee and 59.1 % menthol, which had the highest percentages of sensitivity (40 %), specificity (21 %), positive predictive value (59 %) and negative predictive value (11 %)., Conclusion: Olfactory dysfunction occurs in a significant percentage of pregnant women with COVID-19., (Copyright: © 2021 Permanyer.)

Preeclampsia remains a major cause of worldwide pregnancy related maternal and neonatal mortality and morbidity, it accounts for more than 50,000 maternal deaths each year. The World Health Organization estimates that at least one woman dies every 7 minutes from a complication of preeclampsia. It is the main cause of maternal death in Mexico and Latin America. Standarized assessment and surveillance of women with preeclampsia is associated with reduced maternal risk. Standarized sequence was established to search for practice guidelines from the clinical questions raised on diagnosis and treatment of preeclampsia-eclampsia. The working group selected clinical practice guidelines found in the Cochrane Library, Medline and PubMed. The results were expressed as levels of evidences and grade of recommendation. Evidence suggests, that treatment of severe hypertension, seizures prophylaxis with magnesium sulfate, and management by experienced health-care professionals will improve maternal, fetal and neonatal outcomes. Treatment remains supportive with pregnancy termination being the only definitive cure.

The intracellular compartmentation of pyruvate in primary cultures of cortical neurons was investigated by high resolution (13)C NMR using mixtures of different pyruvate precursors conveniently labeled with (13)C or unlabeled. Cells were incubated with 1-5 mM (1-(13)C, 1,2-(13)C(2) or U-(13)C(6)) glucose only or with mixtures containing 1.5 mM (1-(13)C or U-(13)C(6)) glucose, 0.25-2.5 mM (2-(13)C or 3-(13)C) pyruvate and 1 mM malate. Extracts from cells and incubation media were analyzed by (13)C NMR to determine the relative contributions of the different precursors to the intracellular pyruvate pool. When ((13)C) glucose was used as the sole substrate fractional (13)C enrichments and (13)C isotopomer populations in lactate and glutamate carbons were compatible with a unique intracellular pool of pyruvate. When mixtures of ((13)C) glucose, ((13)C) pyruvate and malate were used, however, the fractional (13)C enrichments of the C2 and C3 carbons of lactate were higher than those of the C2 and C3 carbons of alanine and depicted a different (13)C isotopomer distribution. Moreover, neurons incubated with 1 mM (1,2-(13)C(2)) glucose and 0.25-5 mM (3-(13)C) pyruvate produced exclusively (3-(13)C) lactate, revealing that extracellular pyruvate is the unique precursor of lactate under these conditions. These results reveal the presence of two different pools of intracellular pyruvate; one derived from extracellular pyruvate, used mainly for lactate and alanine production and one derived from glucose used primarily for oxidation. A red-ox switch using the cytosolic NAD(+)/NADH ratio is proposed to modulate glycolytic flux, controlling which one of the two pyruvate pools is metabolized in the tricarboxylic acid cycle when substrates more oxidized or reduced than glucose are used., (Copyright 2001 Wiley-Liss, Inc.)

Ex vivo ¿(13)C, (2)H¿ NMR spectroscopy allowed to estimate the relative sizes of neuronal and glial glutamate pools and the relative contributions of (1-(13)C) glucose and (2-(13)C, 2-(2)H(3)) acetate to the neuronal and glial tricarboxylic acid cycles of the adult rat brain. Rats were infused during 60 min in the right jugular vein with solutions containing (2-(13)C, 2-(2)H(3)) acetate and (1-(13)C) glucose or (2-(13)C, 2-(2)H(3)) acetate only. At the end of the infusion the brains were frozen in situ and perchloric acid extracts were prepared and analyzed by high resolution (13)C NMR spectroscopy (90.5 MHz). The relative sizes of the neuronal and glial glutamate pools and the contributions of acetyl-CoA molecules derived from (2-(13)C, (2)H(3)) acetate or (1-(13)C) glucose entering the tricarboxylic acid cycles of both compartments, could be determined by the analysis of (2)H-(13)C multiplets and (2)H induced isotopic shifts observed in the C4 carbon resonances of glutamate and glutamine. During the infusions with (2-(13)C, 2-(2)H(3)) acetate and (1-(13)C) glucose, the glial glutamate pool contributed 9% of total cerebral glutamate being derived from (2-(13)C, 2-(2)H(3)) acetyl-CoA (4%), (2-(13)C) acetyl-CoA (3%) and recycled (2-(13)C, 2-(2)H) acetyl-CoA (2%). The neuronal glutamate pool accounted for 91% of the total cerebral glutamate being mainly originated from (2-(13)C) acetyl-CoA (86%) and (2-(13)C, 2-(2)H) acetyl-CoA (5%). During the infusions of (2-(13)C, 2-(2)H(3)) acetate only, the glial glutamate pool contributed 73% of the cerebral glutamate, being derived from (2-(13)C, 2-(2)H(3)) acetyl-CoA (36%), (2-(13)C, 2-(2)H) acetyl-CoA (27%) and (2-(13)C) acetyl-CoA (10%). The neuronal pool contributed 27% of cerebral glutamate being formed from (2-(13)C) acetyl-CoA (11%) and recycled (2-(13)C, 2-(2)H) acetyl-CoA (16%). These results illustrate the potential of ¿(13)C, (2)H¿ NMR spectroscopy as a novel approach to investigate substrate selection and metabolic compartmentation in the adult mammalian brain.

The short term effect of heavy water (2H2O) in intracellular pH (pHi) and phosphatidylcholine (PtdCho) turnover have been studied by 31P NMR spectroscopy in the perfused mouse liver metabolizing alanine. Hepatic pHi decreased from 7.19 +/- 0.01 (n = 10) to 7.01 +/- 0.03 (n = 4) after the addition of 6 mM alanine to Krebs Ringer bicarbonate (KRB) perfusion medium. Replacement of 50% of the KRB water with 2H2O during alanine perfusion inhibited the intracellular acidification induced by alanine and caused i) a decrease in the hepatic content of PtdCho, and ii) increases in phosphocholine and glycerophosphocholine, respectively. Amiloride (1 mM) of 5-(N-ethyl-N-isopropyl)-amiloride (10 microM), two previously reported inhibitors of the Na+/H+ exchangers, mimicked the effects produced by 2H2O on pHi and PtdCho turnover. Replacement of 50% of the KRB water with 2H2O or the addition of 1mM amiloride to KRB only, did not modify pHi nor increase the levels of phosphocholine of glycerophosphocholine. Thus, the observed increases are the result of alanine perfusion in the presence of 2H2O or amiloride. These results suggest that 2H2O behaves similarly to previously reported inhibitors of Na+/H+ exchange, disclosing also a novel role for PtdCho metabolism in the regulation on hepatic pHi.