Liver transplantation in Latin America: reality and challenges.

Healthcare systems in Latin America are broadly heterogeneous, but all of them are burdened by a dramatic rise in liver disease. Some challenges that these countries face include an increase in patients requiring a transplant, insufficient rates of organ donation, delayed referral, and inequitable or suboptimal access to liver transplant programs and post-transplant care. This could be improved by expanding the donor pool through the implementation of education programs for citizens and referring physicians, as well as the inclusion of extended criteria donors, living donors and split liver transplantation. Addressing these shortcomings will require national shifts aimed at improving infrastructure, increasing awareness of organ donation, training medical personnel, and providing equitable access to care for all patients.

Characterizing the Biosynthesis of the [Fe(II)(CN)(CO)2(cysteinate)]- Organometallic Product of the Radical-SAM Enzyme HydG by EPR and Mössbauer Spectroscopy.

[FeFe]-hydrogenases employ a catalytic H-cluster, consisting of a [4Fe-4S]H cluster linked to a [2Fe]H subcluster with CO, CN- ligands, and an azadithiolate bridge, which mediates the rapid redox interconversion of H+ and H2. In the biosynthesis of this H-cluster active site, the radical S-adenosyl-l-methionine (radical SAM, RS) enzyme HydG plays the crucial role of generating an organometallic [Fe(II)(CN)(CO)2(cysteinate)]- product that is en route to forming the H-cluster. Here, we report direct observation of this diamagnetic organometallic Fe(II) complex through Mössbauer spectroscopy, revealing an isomer shift of δ = 0.10 mm s-1 and quadrupole splitting of ΔEQ = 0.66 mm s-1. These Mössbauer values are a change from the starting values of δ = 1.15 mm s-1 and ΔEQ = 3.23 mm s-1 for the ferrous "dangler" Fe in HydG. These values of the observed product complex B are in good agreement with Mössbauer parameters for the low-spin Fe2+ ions in synthetic analogues, such as 57Fe Syn-B, which we report here. These results highlight the essential role that HydG plays in converting a resting-state high-spin Fe(II) to a low-spin organometallic Fe(II) product that can be transferred to the downstream maturase enzymes.

Assessment of burnout syndrome and associated factors among medical students during the COVID-19 pandemic.

Background: Overwhelming requirements, a high degree of work, and prolonged exposure to emotionally demanding circumstances in work and life settings can lead to burnout syndrome. The purpose of the study is to assess burnout syndrome and its associated factors among medical students during the COVID-19 pandemic. Methods: A cross-sectional, prospective, descriptive study was conducted in a Mexican medical school during the last week of the spring semester of 2021 using the Maslach Burnout Inventory-Student Survey (MBI-SS) and an associated factors survey. Results: Based on the MBI-SS definition, most students (54.2%, n = 332) had burnout symptoms and high emotional exhaustion (79.6%, n = 448), high cynicism (57.3%, n = 351), and low academic effectiveness (36.4%, n = 223). After adjusting the associated factors, a significant correlation between the school year and the presence of burnout was identified (OR 1.127, 95% CI [1.023-1.241], p<0.05). Regarding the current pandemic, the death of a family member by COVID-19 also put students at risk of developing burnout (OR 1.598*, 95% CI [1.080-2.363, p<0.05]). Limitations: The main limitation of this study was the lack of a control group (before the pandemic); therefore, the high prevalence of burnout can only be hypothesized due to the pandemic but cannot be objectively evidenced. A prospective study after the pandemic is needed to resolve this question. Conclusion: The coronavirus pandemic represents a challenge to the academic and psychological stability of students. It essential to continue assessing burnout levels in medical students and the general population to treat them in time and improve mental health.

Correlation of Internal Jugular Vein Collapsibility With Central Venous Pressure in Patients With Liver Cirrhosis.

We aimed to compare internal jugular vein and inferior vena cava ultrasonography as predictors of central venous pressure in cirrhotic patients. We performed ultrasound assessments of the internal jugular vein (IJV) and the inferior vena cava and then invasively measured central venous pressure (CVP). We then compared their correlation with CVP and performed area under the receiver operating characteristic curves to determine which had best sensitivity and specificity. IJV cross-sectional area collapsibility index at 30° correlated better with CVP ( r = -0.56, P < 0.001), and an IJV AP-CI at 30° ≤ 24.8% was better at predicting a CVP ≥8 mm Hg, with 100% sensitivity and 97.1% specificity. Thus, IJV point-of-care ultrasound might be superior than inferior vena cava point-of-care ultrasound as a predictor of CVP in cirrhotic patients.

Payment with knowledge: A method for a training of anatomy near-peer teachers and formation of future anatomists.

Near-peer teaching has been widely implemented in medical schools and the benefits for the near-peer teachers (NPTs), the students, and the institution have been well documented. However, NPT training methods and perceptions of such have been limited. A four-year clinical anatomy and surgical training program was established (est. 2019) as part of the continuous training timeline for NPTs (n > 60 total) formation at the Universidad Autónoma de Nuevo León, in Mexico. The program provides various training courses for the NPTs according to their hierarchy, including teaching skills, professional development, psychosocial aspects, and career objectives. A "Clinical Anatomy and Surgical Training Diploma" was planned with 12 modules to aid in developing these abilities, along with a higher understanding of clinical anatomy shared by expert clinical specialists, and diverse clinical and surgical skills such as suturing, catheterization, and basic surgical procedures. The program has a completion rate of approximately 15 NPTs/year. All, while creating an environment with a sense of belonging, and facilitating mentorship between fellow NPTs and educators. Near-peer teachers develop leadership, communication, and teaching skills. The program has provided a constant source of anatomy educators, avoiding any shortage.

Factors Influencing Scientific Achievements of Medical Students in the Anatomy Research Group: An Analysis From the Autonomous University of Nuevo León in Mexico.

Scientific research and student involvement are critical to the formation of physicians, yet the number of medical researchers has decreased over time. To implement corrective strategies, the variables associated with positive research attitudes and productivity among medical students must be identified. The aim of this study was to evaluate the variables associated with students interested or involved in research. A validated questionnaire was applied to the student members of an established anatomy research group in a Mexican medical school with a six-year medical program. Data were collected and analyzed. A total of 85.5% (n = 77/90) students answered the survey with most respondents being second-year medical students. The majority of respondents indicated that the important component of conducting research was a contribution to the new knowledge (45.5%) and to the scientific community (42.9%). More than half of respondents mentioned a professor or a peer as the initial motivation to become involved in research. Lack of time was the main limitation (59.7%) to research involvement. Perceived benefits were knowledge and team work skills. Of those involved, most (85.7%) wished to continue participating in research as a complement to their clinical work. Professors and student colleagues were found to play an important motivational and recruitment role for medical research. These efforts in turn have developed into long-lasting mentor-mentee relationships. Students also anticipated that early involvement in research will positively influence the likelihood of future physicians' contribution and collaboration in research.

A Uranium(II) Arene Complex That Acts as a Uranium(I) Synthon.

Two-electron reduction of the amidate-supported U(III) mono(arene) complex U(TDA)3 (2) with KC8 yields the anionic bis(arene) complex [K[2.2.2]cryptand][U(TDA)2] (3) (TDA = N-(2,6-di-isopropylphenyl)pivalamido). EPR spectroscopy, magnetic susceptibility measurements, and calculations using DFT as well as multireference CASSCF methods all provide strong evidence that the electronic structure of 3 is best represented as a 5f4 U(II) metal center bound to a monoreduced arene ligand. Reactivity studies show 3 reacts as a U(I) synthon by behaving as a two-electron reductant toward I2 to form the dinuclear U(III)-U(III) triiodide species [K[2.2.2]cryptand][(UI(TDA)2)2(µ-I)] (6) and as a three-electron reductant toward cycloheptatriene (CHT) to form the U(IV) complex [K[2.2.2]cryptand][U(η7-C7H7)(TDA)2(THF)] (7). The reaction of 3 with cyclooctatetraene (COT) generates a mixture of the U(III) anion [K[2.2.2]cryptand][U(TDA)4] (1-crypt) and U(COT)2, while the addition of COT to complex 2 instead yields the dinuclear U(IV)-U(IV) inverse sandwich complex [U(TDA)3]2(µ-η8:η3-C8H8) (8). Two-electron reduction of the homoleptic Th(IV) amidate complex Th(TDA)4 (4) with KC8 gives the mono(arene) complex [K[2.2.2]cryptand][Th(TDA)3(THF)] (5). The C-C bond lengths and torsion angles in the bound arene of 5 suggest a direduced arene bound to a Th(IV) metal center; this conclusion is supported by DFT calculations.

Tracing the incorporation of the "ninth sulfur" into the nitrogenase cofactor precursor with selenite and tellurite.

Molybdenum nitrogenase catalyses the reduction of N2 to NH3 at its cofactor, an [(R-homocitrate)MoFe7S9C] cluster synthesized via the formation of a [Fe8S9C] L-cluster prior to the insertion of molybdenum and homocitrate. We have previously identified a [Fe8S8C] L*-cluster, which is homologous to the core structure of the L-cluster but lacks the 'ninth sulfur' in the belt region. However, direct evidence and mechanistic details of the L*- to L-cluster conversion upon 'ninth sulfur' insertion remain elusive. Here we trace the 'ninth sulfur' insertion using SeO32- and TeO32- as 'labelled' SO32-. Biochemical, electron paramagnetic resonance and X-ray absorption spectroscopy/extended X-ray absorption fine structure studies suggest a role of the 'ninth sulfur' in cluster transfer during cofactor biosynthesis while revealing the incorporation of Se2-- and Te2--like species into the L-cluster. Density functional theory calculations further point to a plausible mechanism involving in situ reduction of SO32- to S2-, thereby suggesting the utility of this reaction to label the catalytically important belt region for mechanistic investigations of nitrogenase.

Comparison of suturing models: the effect on perception of basic surgical skills.

BACKGROUND: Acquisition of Basic Surgical Skills (BSS) are essential for medical students. The objective was to determine it's fidelity impact. METHODS: Using four suturing models (SM) (pigskin, sponge, commercial pad, and orange), SM-quality and student-SM interaction were evaluated. After a 1-h class, participants were divided into groups and randomly assigned exercises in SM in 15-min intervals. The experiment included completing three individual simple stitches and a 3-stitch continuous suture in each SM. RESULTS: Eighty-two medical students participated. Suturing quality was better in pigskin and sponge, which were also the preferred models (p < 0.001). Significant differences in quality between the insertion and exit point, and firmness of knots (p < 0.05) in both simple and continuous sutures, as well as between length and distance in continuous ones (p < 0.001) were identified. CONCLUSIONS: Acquisition and quality of BSS are influenced by the intrinsic characteristics of SM. An adequate degree of resistance, consistency, and elasticity are necessary.

Lower Frequency of Call Shifts Leads to Higher Attendance, Higher Academic Performance, and Less Burnout Syndrome in Surgical Clerkships.

OBJECTIVE: Clinical clerkships are a fundamental component of medical education where students' learning is aided by exposure to real patients in diverse practical settings. Countless programs use overnight call shifts as an essential part of their clerkships. There has been concerns about the negative effects these shifts have on students. The study aims to determine relations between call schedule, lecture attendance, and academic and clinical performance. METHODS: One hundred and eight medical students were followed during their surgery clerkship. Students on a Q3 schedule had an on-call shift once every 3 nights, while students on a Q4 schedule once every 4 nights. Their academic performance was evaluated using their exams grades, while their clinical performance was evaluated by their attending physicians. Burnout syndrome was measured using Maslach Inventory. RESULTS: A total of 108 medical students attended their surgical clerkship. Sixty-nine students were under the Q3 call schedule while 39 students in the Q4 call schedule. Mean lecture attendance for students in Q3 was 82.7% (17.3%) compared to 90% (11.2%) (p = 0.020). Final exam grades were different between groups, with Q3 scoring a mean 71.55 (9.3) compared to Q4 85.07 (9.8) (p = 0.001). Clinical performance score means were similar between groups (p = 0.777). Q4 had 74% and Q3 had 49.3% of the students with >90% of attendance (p = 0.008). Q4 had 2.6% students with <70% attendance compared to Q3 with 23.2% (p = 0.008). Students with >90% attendance regardless of call schedule, scored higher in both midterms and final exams (p = 0.002; p = 0.001). Burnout prevalence was higher in students on the Q3 schedule with 28.6% compared to 4.7% of those on the Q4 schedule (p = 0.003). CONCLUSIONS: Students with less call frequency were associated with an improvement in lecture attendance and academic performance, and a lower burnout syndrome rate, without impacting clinical performance. Students with higher attendance regardless of call schedules performed higher academically. Further studies should evaluate the impact on clinical performance and exposure more thoroughly.

Gynecological influencing factors on the rectovaginal septum's morphology.

INTRODUCTION AND HYPOTHESIS: The objective was to determine the mean morphometric characteristics of the rectovaginal septum (RVS) and its variations in correlation with the number of pregnancies, method of delivery, parity, and estrogenic exposure. METHODS: An observational, cross-sectional, retrospective, descriptive, and comparative study was carried out. Pelvic MRI of Hispanic women (≥15 years of age) from the northeast of Mexico were obtained. Age and obstetric and gynecological history were registered and the sample women were categorized by their variables. Length and thickness measurements were standardized. RESULTS: A total of 102 MRI studies were included, with a mean age of 41; 24.5% were nulligravida, the rest primi- or multigravida. Vaginal delivery was the most common type (49.35%), 16.88% had a cesarean section, and 31.17% had mixed delivery. 74.5% of the women were premenopausal. The mean RVS length was 73.2 ± 15.3 mm, with a thickness of 2.8 ± 1.7, 2.2 ± 1.2, and 2.5 ± 1.3 mm for the upper, middle, and lower thirds respectively. There were tendencies to increase the length of the RVS, and the thickness of the upper and middle thirds in the non-pregnancy and the at-least-one-pregnancy groups; to increase the length and middle-third thickness in those with mixed delivery, and increased upper- and lower-third thickness in those with only a cesarean section. Multiparous women with vaginal delivery had significantly longer and thicker RVS than primiparous. Premenopausal women had significantly longer RVS with a tendency to lose thickness toward postmenopause. CONCLUSIONS: The morphology of RVS can be modified by different factors such as age, number of pregnancies, number of births, and estrogenic exposure. This structure should be evaluated and taken into account in preoperative management and surgical technique planning.

Use of Reticulated Open Cell Foam Dressings With Through Holes During Negative Pressure Wound Therapy With Instillation and Dwell Time: A Large Case Study.

INTRODUCTION: Negative pressure wound therapy with instillation and dwell time (NPWTi-d) has been utilized in wounds with positive clinical benefits. A reticulated open cell foam dressing with through holes (ROCF-CC) was developed to assist with wound cleansing by removing thick wound exudate and infectious materials, and it may be used when debridement is not possible or appropriate. Use of NPWTi-d with ROCF-CC dressings has been reported with positive outcomes in complex wounds. OBJECTIVE: The present study reports the authors' experience using NPWTi-d with ROCF-CC dressings in 19 patients with complex wounds. MATERIALS AND METHODS: Of the 19 patients, 8 underwent sharp debridement. Oral and/or intravenous antibiotic treatment was initiated as needed prior to NPWTi-d. All patients received NPWTi-d with ROCF-CC dressings with instillation of quarter-strength Dakin's solution, hypochlorous acid solution, or saline with a dwell time of 5 to 10 minutes, followed by 2 to 3.5 hours of continuous negative pressure at -125 mm Hg. Dressing changes occurred every 2 to 3 days. Measurements and assessments of wound progression were done as per institutional protocols. RESULTS: The 19 treated patients consisted of 10 males and 9 females, with an average age of 58.2 ± 15.1 years. Common patient comorbidities included hypertension, diabetes, obesity, and paraplegia. Wound types included pressure injuries, traumatic wounds, and surgical wounds. The average length of NPWTi-d use was 9.5 ± 4.1 days. In all of the patients, the wound beds showed development of healthy granulation tissue following NPWTi-d with ROCF-CC. All patients were discharged to one of the following: another hospital facility, skilled nursing facility, long-term acute care facility, or home. CONCLUSIONS: In the authors' clinical practice, NPWTi-d with ROCF-CC provided effective and rapid removal of thick exudate and infectious materials and promoted development of granulation tissue.

Lewis acid capping of a uranium(v) nitride via a uranium(iii) azide molecular square.

Reaction of (CpiPr4)2UI with NaN3 resulted in formation of tetrameric uranium(iii) azide-bridged 'molecular square' [(CpiPr4)2U(µ-η1:η1-N3)]4 (1). Addition of B(C6F5)3 to 1 induced loss of N2 at room temperature, yielding the uranium(v) borane-capped nitrido (CpiPr4)2U(µ-N)B(C6F5)3 (2).

Closed Incision Negative Pressure Therapy: Review of the Literature.

Surgical site infection and other common surgical site complications (dehiscence, hematoma, and seroma formation) can lead to serious and often life-threatening complications. Gauze, adhesive dressings, and skin adhesives have traditionally been utilized for incision management. However, the application of negative pressure wound therapy over clean, closed surgical incisions (closed incision negative pressure therapy, ciNPT), has become a recent option for incision management. A brief review of ciNPT clinical evidence and health economic evidence are presented. A brief literature review was performed using available publication databases (PubMed, Ovid®, Embase®, and QUOSA™) for articles in English reporting on the use of ciNPT between October 1, 2016, to March 31, 2019. The successful application of ciNPT over clean, closed wounds has been reported in a broad spectrum of patients and operative interventions, resulting in favorable clinical results. Four of the five studies that examined health economics following the use of ciNPT reported a potential reduction in the cost of care. The authors' own experience and published results suggest that patients at high risk for developing a surgical site complication may benefit from the use of ciNPT during the immediate postoperative period. Additional studies are needed across various surgical disciplines to further assess the safety, and cost-effectiveness of ciNPT use in patient populations.

Polymorphic eruption of pregnancy in Mexico.

BACKGROUND: Currently, the exact incidence of Polymorphic Eruption of Pregnancy (PEP) in the Mexican population is unknown. PEP tends to manifest in the abdomen, primarily in the stretch marks caused by distension. It is characterized by severely pruritic urticarial-like papules that converge in plaques, extending to the buttocks and proximal thighs. Our study determined its incidence, along with other common dermatoses in pregnancy. METHODS: Patients between 14 and 45 years of age were evaluated. In each patient, a complete medical history and physical examination was performed with emphasis on skin and adnexa. Patients were followed until the end of their pregnancy. RESULTS: A total of 217 women were included. PEP was identified in three patients (1.38%), all primigravida, with single fetus pregnancy, and all concluded their pregnancy by vaginal delivery. The neonates were 2 females and 1 male. No other gestational pathologies were identified. CONCLUSIONS: We identified a higher incidence of PEP than reported, without association to complications or need for medical management. There may be an association between high maternal weight and the presence of PEP, however a larger sample is needed.

[Perfil de expresión de Ki67 en lesiones melanocíticas palmoplantares: estudio de casos y controles]. / Expression profile of Ki67 in palmoplantar melanocytic lesions: a case-control study.

INTRODUCCIÓN: El melanoma acral lentiginoso es una neoplasia maligna que afecta a población predominantemente no caucásica. Debido al diagnóstico tardío suele tener mal pronóstico, además de que se considera una neoplasia biológicamente más agresiva, incluso cuando se detecta tempranamente. OBJETIVO: Determinar la expresión de Ki67 en el melanoma acral lentiginoso invasor y compararla con los nevos acrales. MÉTODO: Estudio transversal, descriptivo, observacional. Se realizó inmunohistoquímica con marcador Ki67 en 17 biopsias de melanoma acral lentiginoso invasor (casos) y 17 biopsias de nevos palmoplantares (controles). Se determinó la expresión nuclear de Ki-67 y se comparó entre ambos grupos. RESULTADOS: La media de expresión de Ki67 fue del 8.5% en el grupo control y del 34% en el grupo de melanomas, siendo esta diferencia estadísticamente significativa (p < 0.0001). DISCUSIÓN: La expresión de Ki67 en los melanomas acrales es considerablemente mayor que en los nevos acrales. El valor pronóstico del marcador Ki67 sigue siendo considerado controversial. Sin embargo, hay estudios en los que en combinación con otros marcadores se refuerza su valor pronóstico. CONCLUSIONES: Por la gran diferencia en inmunorreactividad de Ki67 entre melanomas y nevos, la expresión de Ki67, referida como índice proliferativo, podría ser considerada como factor pronóstico incluso más objetivo que el índice mitótico. BACKGROUND: Acral lentiginous melanoma is a malignant neoplasm which appears in hands and feet. Acral lentiginous melanoma has an unclear etiology, and usually affects non-Caucasian population. Because it is frequently diagnosed lately, acral melanoma has bad prognosis; however, it is biologically more aggressive than other clinicopathological types of melanoma, even when diagnosed early. OBJECTIVE: To determine the expression of Ki67 in invasive lentiginous acral melanoma and to compare it with acral nevi. METHOD: Cross-sectional, descriptive, observational study. Immunohistochemistry with Ki67 marker was performed on 17 biopsies of invasive lentiginous acral melanoma (cases) and 17 biopsies of palmoplantar nevi (controls). Nuclear expression of Ki-67 was determined and both were compared between both groups. RESULTS: The mean expression of Ki67 was 8.5% in the control group, and 34% in the melanoma group, which was statistically significant (p < 0.0001). DISCUSSION: Ki67 expression in acral lentiginous melanomas is higher than in acral nevi. Prognostic value of Ki67 is still considered controversial. However, there are several studies where, in combination with other markers, their prognostic value is reinforced. CONCLUSIONS: Due to the wide gap in Ki67 expression between melanomas and nevi showed in this study, Ki67 expression, referred to as a proliferative index, could be considered as a prognostic factor even more objective than the mitotic index.

Human Umbilical Vessels: Choosing the Optimal Decellularization Method.

There is an increasing demand of small-diameter vascular grafts for treatment of circulatory pathologies. Decellularization offers the possibility of using human blood vessels as scaffolds to create vascular grafts. Umbilical vessels have great potential because of their availability and morphological characteristics. Various decellularization techniques have been used in umbilical vessels, but consensus on which is the most appropriate has not yet been reached. The objective of this review is to analyze the morphological and biomechanical characteristics of decellularized human umbilical arteries and veins with different techniques. Evidence indicates that the umbilical vessels are a viable option to develop small-diameter vascular grafts. Detergents are the agents most often used and with most evidence. However, further studies are needed to accurately analyze the components of the extracellular matrix and biomechanical characteristics, as well as the capacity for recellularization and in vivo functionality.

Genome Sequences of Mycobacteriophages Kerberos, Pomar16, and StarStuff.

We describe the genome sequences of three closely related mycobacteriophages, Kerberos, Pomar16, and StarStuff, isolated at similar times but from geographically distinct regions. All three genomes are similar to those of other subcluster A2 phages, such as L5 and D29, are temperate, and have siphoviral virion morphologies.

Willingness toward organ and body donation among anatomy professors and students in Mexico.

Most anatomists agree that cadaver dissection serves as a superior teaching tool in human anatomy education. However, attitudes toward body donation vary widely between different individuals. A questionnaire was developed to determine the attitudes toward body and organ donation among those who learn the most from cadavers: medical students, medical student teaching assistants, medical students involved in research, and anatomy professors. A cross-sectional, prospective study was designed in which the questionnaire was distributed among first-year human anatomy students before undertaking cadaver dissection at the beginning of the semester, and then again after a commemoration service at the end of the course. The questionnaire items included demographic data, as well as questions designed to characterize participants' attitudes regarding body/organ donation from strangers, family members, and whether participants would consider such practices with their own bodies. Out of a total of 517 students enrolled in the Human Anatomy course in the Medical School at the Universidad Autónoma de Nuevo León, Mexico during January to June 2016, 95% responded to the first (491) and second (490) surveys. Participants' opinions on their own organ donation was similar before and after exposure to cadaver dissection, with between 87% and 81% in favor of such practices, and only 3% against it, in both surveys. Participants' willingness to donate their own bodies, as well as those of family members, increased, while reluctance regarding such practices decreased by half (P < 0.0001 and P < 0.05). Professors had the highest rates of positive opinions regarding their own body donation (74.9%), with 18.8% undecided. Low opposition toward organ and body donation remains prevalent among both anatomists and physicians in training in Mexico. Anat Sci Educ 10: 589-597. © 2017 American Association of Anatomists.