Short-Term Effects of Global Pelvic Manipulation on Knee Joint Position Sense in Asymptomatic Participants: A Double-Blind Randomized Controlled Trial.

OBJECTIVE: The purpose of this study was to evaluate short-term effects of the global pelvic manipulation (GPM) on knee joint position sense (JPS). METHODS: This randomized, controlled double-blind trial included 26 asymptomatic participants (X¯± 25.3; standard deviation ± 4.4 years) who were randomly allocated into 2 groups. Sixteen participants were allocated into the experimental group, in which GPM was performed, and the rest of the participants (n = 10) were included in the control group, which received sham ultrasound therapy. Each participant attended 1 session only, and the evaluations were assessed pretreatment and 5 minutes posttreatment through an isokinetic dynamometer (Biodex Medical Systems), in which the data regarding knee JPS ipsilateral to the manipulated sacroiliac joint were collected. Mann-Whitney and Wilcoxon tests were used, with a 95% significance level. RESULTS: There were no statistically significant differences between the groups concerning active and passive JPS at 30° and 60° (P > .05). The results showed a lack of significant differences between the moments in both groups (P > .05). CONCLUSION: This investigation demonstrated that GPM, with high-velocity low-amplitude thrust, has no effect on knee JPS, suggesting that this manipulative technique does not have a relative effect on muscle spindles and Golgi tendon organ activation in asymptomatic participants.

Dynamics of Surfactant Clustering at Interfaces and Its Influence on the Interfacial Tension: Atomistic Simulation of a Sodium Hexadecane-Benzene Sulfonate-Tetradecane-Water System.

The process of equilibration of the tetradecane-water interface in the presence of sodium hexadecane-benzene sulfonate is studied using intensive atomistic molecular dynamics simulations. Starting as an initial point with all of the surfactants at the interface, it is obtained that the equilibration time of the interface (several microseconds) is orders of magnitude higher than previously reported simulated times. There is strong evidence that this slow equilibration process is due to the aggregation of surfactants molecules on the interface. To determine this fact, temporal evolution of interfacial tension and interfacial formation energy are studied and their temporal variations are correlated with cluster formation. To study cluster evolution, the mean cluster size and the probability that a molecule of surfactant chosen at random is free are obtained as a function of time. Cluster size distribution is estimated, and it is observed that some of the molecules remain free, whereas the rest agglomerate. Additionally, the temporal evolution of the interfacial thickness and the structure of the surfactant molecules on the interface are studied. It is observed how this structure depends on whether the molecules agglomerate or not.

On the electron density localization in elemental cubic ceramic and FCC transition metals by means of a localized electrons detector.

The electron density localization in insulator and semiconductor elemental cubic materials with diamond structure, carbon, silicon, germanium, and tin, and good metallic conductors with face centered cubic structure such as α-Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au, was studied using a localized electrons detector defined in the local moment representation. Our results clearly show an opposite pattern of the electron density localization for the cubic ceramic and transition metal materials. It was found that, for the elemental ceramic materials, the zone of low electron localization is very small and is mainly localized on the atomic basin edges. On the contrary, for the transition metals, there are low-valued localized electrons detector isocontours defining a zone of highly delocalized electrons that extends throughout the material. We have found that the best conductors are those in which the electron density at this low-value zone is the lowest.

Changes in co-contraction magnitude during functional tasks following anterior cruciate ligament reconstruction: A systematic review.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) is a common orthopedic surgery procedure whose incidence has increased over the past few decades. Nevertheless, it is believed that neuromuscular control remains altered from the early stages after ACLR to later years. Therefore, the aim of this study was to systematically evaluate the magnitude of co-contraction during functional tasks in subjects with unilateral ACLR. METHODS: A systematic review design was followed. The search strategy was conducted in PubMed, Scopus, EBSCO, PEDro, Cochrane Library, and Web of Science databases from inception to March 2024. The inclusion criteria involved studies using electromyography (EMG) data to calculate muscle pair activation via the co-contraction index (CCI) in ACLR individuals during functional tasks. The Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and study quality was evaluated using National Institutes of Health (NIH) Study Quality Assessment Tools. RESULTS: The search strategy found a total of 792 studies, of which 15 were included in this systematic review after reviewing the eligibility criteria. The magnitude of co-contraction was assessed in a total of 433 ACLR individuals and 206 controls during functional tasks such as hop, drop-land, step-up/step-down, and gait. Overall, approximately 79.6% of individuals who had undergone ACLR exhibited increased levels of co-contraction magnitude in the ACLR limb, while 8.5% showed low co-contraction levels. CONCLUSIONS: The findings of the review suggest that, during functional tasks, most individuals who have undergone ACLR exhibit changes of co-contraction magnitude in the involved limb.

Charts for fetal age assessment based on fetal sonographic biometry in a population from Cali, Colombia.

OBJECTIVES: To create reference charts for fetal age assessment based on fetal sonographic biometry in a population of pregnant women living in the third largest city in Colombia and compare them with charts included in ultrasound machines. METHODS: The study data were obtained from women with a single pregnancy and confirmed gestational age between 12 and 40 completed weeks. All women were recruited specifically for the study, and every fetus was measured only once for biparietal diameter, head circumference, abdominal circumference, and femur length. Polynomial regression models for gestational age as a function of each fetal measurement were fitted to estimate the mean and standard deviation. Percentile curves of gestational age were constructed for each fetal measurement using these regression models. RESULTS: Biparietal diameter, head circumference, abdominal circumference, and femur length were measured in 792 fetuses. Tables and charts of gestational age were derived for each fetal parameter. A cubic polynomial model was the best-fitted regression model to describe the relationships between gestational age and each fetal measurement. The standard deviation was estimated by simple linear regression as a function of each fetal measurement. Comparison of our gestational age mean z scores with those calculated by reference equations showed statistically significant differences (P < .01). CONCLUSIONS: We present a set of reference charts, tables, and formulas for fetal age assessment based on fetal sonographic biometry. The results support the recommendation that these charts and tables could be more appropriate for assessing fetal age in Colombian populations than those currently included in the software of ultrasound machines.

Fetal size charts for a population from Cali, Colombia: sonographic measurements of biparietal diameter, head circumference, abdominal circumference, and femur length.

OBJECTIVES: To create reference charts for fetal sonographic biometric measurements in a population of pregnant women living in the third largest city in Colombia and compare them with charts included in ultrasound machines. METHODS: The data were obtained from women with a single pregnancy and confirmed gestational (menstrual) age between 12 and 40 weeks. All women were recruited specifically for the study, and every fetus was measured only once for biparietal diameter, head circumference, abdominal circumference, and femur length. Raw data for each fetal measurement were modeled by fitting regression models separately to estimate the mean and standard deviation as a function of gestational age. Percentile curves were constructed for each measurement by gestational age using these two regression models. We compared our mean z scores with those expected by reference equations. RESULTS: Measurements were obtained for 792 fetuses. A cubic polynomial model was the best-fitted regression model to describe the relationships between each fetal measurement and gestational age. The standard deviation for each measurement was estimated by simple linear regression as a function of gestational age. Comparison of our mean z scores with those by reference equations showed significant differences in some fetal measurements (P < .01). CONCLUSIONS: We present a set of reference percentile charts, tables, and formulas for fetal biometric measurements from a Colombian population. We believe that our fetal charts could be used nationwide in Colombia; nevertheless, a national sample will contribute to their validation and promotion of the development of Colombian fetal size charts.

Reverse buoyancy in a vibrated granular bed: Computer simulations.

We have performed molecular dynamics simulations of an intruder in a vibrated granular bed including interstitial fluid effects to account for the phenomenon of reverse buoyancy. We show that our model is able to reproduce the overall behaviour observed by previous experimental works and is the first finite-elements simulation to show the sinking of intruders lighter than the granular bed. To further advance our comprehension of this phenomenon, we studied the motion of the intruders in a single vibration cycle with respect to the bottom of the granular column, finding a substantial qualitative difference for heavy and light intruders and we compare these results with experiments using fine-sized glass beads. We show that, though heavy intruders seem unaffected by the force due to the fluid, the effect on light intruders is remarkable.

Exploring the nature of the interactions between the molecules of the sodium dodecyl sulfate and water in crystal phases and in the water/vacuum interface.

The nature of the interaction between the molecules of the sodium dodecyl sulfate surfactant forming two crystal phases, one anhydrous, NaC12H25O4S and the other, NaC12H25O4S.H2O, hydrated with one water molecule for unit cell, has been studied in detail using the quantum theory of atoms in molecules and a localized electron detector function. It was found that for the anhydrous crystal, the head groups of the surfactant molecules are linked into a head-to-head pattern, by a bond path network of Na-O ionic bonds, where each Na+ atom is attached to four S O 4 - groups. For the hydrated crystal, in addition to these four bonds for Na+, two additional ones appear with the oxygen atoms of the water molecules, forming a bond paths network of ionic Na-O bonds, that link the Na+ atoms with the S O 4 - groups and the H2O molecules. Each H2O molecule is bonded to two S O 4 - groups via hydrogen bonds, while the S O 4 - groups are linked to a maximum of four Na+ atoms. The phenomenon of aggregation of the sodium dodecyl sulfate molecules at the liquid water/vacuum interface was studied using NVT molecular dynamics simulations. We have found that for surfactant aggregates, the Na+ ions are linked to a maximum of three SO4 - groups and three water molecules that form Na-O bonds. Unlike hydrated crystal, each of the O atoms that make these Na-O bonds is linked to only one Na+ ion. Despite these differences, like the crystal phases, the surfactant molecules tend to form a head-to-head network pattern of ionic Na-O bonds that link their heads. The present results indicate that the clustering of anionic surfactant at the water/vacuum interface is a consequence of the electrostatic alignment of the cationic and anionic groups as occurs in the crystalline phases of sodium dodecyl sulfate.

Scanning the critical fluctuations: application to the phenomenology of the two-dimensional XY model.

We show how applying field conjugated to the order parameter may act as a very precise probe to explore the probability distribution function of the order parameter. Using this "magnetic-field scanning" on large-scale numerical simulations of the critical two-dimensional XY model, we are able to discard the conjectured double-exponential form of the large-magnetization asymptote.

Topological transition in a two-dimensional model of liquid crystal.

Simulations of nematic-isotropic transition of liquid crystals in two dimensions are performed using an O2 vector model characterized by nonlinear nearest neighbor spin interaction governed by the fourth Legendre polynomial P4. The system is studied through standard finite-size scaling and conformal rescaling of density profiles of correlation functions. A topological transition between a paramagnetic phase at high temperature and a critical phase at low temperature is observed. The low temperature limit is discussed in the spin wave approximation and confirms the numerical results.

Intrafetal alcohol chemosclerosis of acardiac twins: a multicenter experience.

OBJECTIVE: To report a multicenter experience with intrafetal alcohol chemosclerosis in the treatment of pregnancies complicated with the twin reversed arterial perfusion sequence. METHODS: Percutaneous injection of 1- 2 ml of absolute alcohol into the intra-abdominal segment of the single umbilical artery was performed in 8 acardiac twins. Cases were collected from 5 centers following a standardized protocol. The procedure was performed under continuous ultrasound control, using color Doppler ultrasound to identify the main arterial vessel entering the abdomen of the acardiac twin and passing a 20-gauge spinal needle into the targeted vessel. Intraoperative and short-term complications were noted. Information on pregnancy outcome was obtained by reviewing the medical records or contacting the referring obstetrician. RESULT: At the time of the procedure, the acardiac twin was severely hydropic and the size exceeded 70% of the size of the pump twin in all cases. In addition, there were associated complications in all the pump twins including polyhydramnios in 8 cases (100%), cardiac insufficiency in 5 (63%), and fetal growth restriction in 1 (13%). The procedure was performed at a mean gestational age of 24.7 weeks (range 20-32), and it was technically successful in all cases. However, it was complicated with thrombosis of the umbilical vessels of the pump twin in 1 case, and transient bradycardia in 2 others. These 3 pump twins died in utero as a result of the procedure. The other 5 procedures were technically and clinically successful, resulting in an overall survival rate of 63%. In 4 pregnancies, the pump twin was delivered after 35 weeks and had no neonatal complications. CONCLUSIONS: Intrafetal alcohol chemosclerosis is a simple procedure that can be performed in any fetal medicine center around the world to stop the vascular supply to acardiac twins. However, the main concern with this technique is intravascular transfer of the ablative material to the circulation of the pump twin. The use of this technique should therefore be restricted to those pregnancies with poor prognostic factors and in countries where more sophisticated methods for the treatment of this condition are not available.

Radiolocalización con arpón en lesiones subclínicas de la mama: experiencia del Instituto de Oncología Luis Razetti / Radiolocalization with harpoon in lesions subclinical of she suckles: experience of the Oncological Institute Luis Razetti

La creciente utilización de la mamografía de pesquisa ha contribuido a un rápido aumento en el diagnóstico de lesiones mamarias no palpables; los signos mamográficos de malignidad son principalmente: las microcalcificaciones y los cambios de densidad. En el Servicio de Patología Mamaria del I.O.L.R desde enero de 2000 a julio de 2001, fueron operados por radiocalización con arpón, 27 casos en pacientes con lesiones subclínicas. La edad promedio fue de 48 años (28-67). Todas las lesiones fueron detectadas por mamografía, siendo predominantes las microcalcificaciones: 19 casos (70,4 por ciento), nódulos: 4 casos (14,8 por ciento), combinación ambos: 3 casos (11,1 por ciento) y distorsión arquitectura: 1 caso (3,7 por ciento). Las lesiones fueron resecadas en su totalidad con márgenes libres en 24 casos (88,9 por ciento), y los restantes 3 casos requirieron ampliación de márgenes. El volumen promedio de la pieza fue aproximado de 82 cc. El resultado histológico reportó: lesión premaligna: 2 casos (7,4 por ciento), carcinoma in situ: 4 casos (14,8 por ciento), carcinoma microinfiltrante: 1 caso (3,7 por ciento), carcinoma infiltrante: 2 casos (7,4 por ciento), representando un 33 por ciento del total; el resto correspondió a patologías benignas, en las cuales, las frecuentes fueron: condición fibroquística: 15 casos (55,6 por ciento), adenosis: 8 casos (29,6 por ciento), ectasia ductal: 5 casos (18,5 por ciento), entre otras. Este trabajo demuestra la efectividad del método, y su utilidad para el diagnóstico histológico de lesiones subclínicas sospechosas. Nuestros resultados de patología premaligna y maligna de un 33 por ciento de los casos, son similares a las publicaciones internacionales, indicando una adecuada selección clínica de los pacientes de riesgo

Lesiones subclínicas de la mama técnica de ROLL: experiencia en el Instituto de Oncología Luis Razetti / Subclinical breast lesions technique of ROLL: experience in the Oncology Institute Luis Razetti

Evaluar la aplicación del método R.O.L.L en el diagnóstico de lesiones subclínicas de la mama. Se evalúan prospectivamente 20 pacientes con lesiones subclínicas de la mama, clasificadas como lesiones BIRADS 4 ó 5, admitidas en el Instituto de Oncología "Luis Razetti" desde enero hasta julio de 2001. El procedimiento se realizó aplicando 48 horas antes del acto quirúrgico, una semilla de yodo a nivel de la lesión en estudio, bajo guía mamográfica. El día del acto quirúrgico se procedía, guiado por gammacámara manual (Europrobe), a biopsia escisional de la lesión sospechosa. La edad promedio fue 54,3 años. En todos los casos, el método diagnóstico inicial fue la mamografía. Se observaron 18 de las lesiones BIRADS 4 y 2 lesiones BIRADS 5, correspondiendo a 10 microcalcificaciones, 3 nódulos sólidos y 7 distorsiones de la arquitectura mamaria. Se ubicaron en el 77 por ciento de los casos en el cuadrante superoexterno. Se obtuvieron 20 por ciento de lesiones malignas (2 casos de carcinoma ductal in situ, 1 carcinoma ductal infiltrante y 1 hiperplasia ductal atípica). Un solo espécimen quirúrgico presentó márgenes positivos. El volumen promedio de las piezas operatorias extraídas fue de 34,056 ml. La localización de lesiones subclínicas de mama, utilizando semillas de yodo y gammacámara manual es un método efectivo, fácil de utilizar y que permite un diagnóstico histológico con menor cantidad de tejido mamario sano extirpado

Permeabilidad de la barrera hematoencefálica al magnesio magnesio en preeclampsia

Objetivo: Determinar si el magnesio cruza la barrera hematoencefálica en pacientes con preeclampsia. Material y Métodos: Se seleccionaron 41 embarazadas, 20 con preeclampsia(grupo de estudio) y 21 sin preeclampsia (grupo control). El grupo con preeclampsia recibió sulfato de magnesio en bolo inicial de 4 gr vía intravenosa y 1 gr/hora en dosis de mantenimiento. El grupo control no recibió sulfato de magnesio. A todas las pacientes se les practicó operación de cesárea(por indicación obstétrica) y se les recolectó 1 cm3 de líquido cefalorraquídeo en el momento de la punción espinal para la anestesia regional. Se mostraron además muestras de sangre periférica basal y 2 horas después. En todas las muestras se midió concentración de magnesio. Lo cual se hizo de menera ciega por uno de los investigadores. Resultados: Los niveles de magnesio en líquido cefalorraquídeo no fueron significativamente diferentes entre los dos grupos 4.88 mEq/L (grupo control) y 5.58 mEq/L (grupo estudio) (p=0.29). En contraste, los niveles séricos de magnesio fueron significativamente más altos en el grupo con preeclampsia(5.91 mEq/L) que en el grupo control (4.27 mEq/L) (p menor 0.003). Conclusiones: La barrera hematoencefálica parece no ser permeable al paso del ión magnesio en la preeclampsia

Fístulas rectovaginales actínicas experiencia en el I.O.L.R / Actnics rectovaginal fistulas: experience in the I.O.L.R

Siendo la morbimortalidad del carcinoma invasor del cérvix uterino tan elevada, tanto por la patología per se como por el tratamiento que requiere para su erradicación, debe insistirse en su prevención. Se reconoce a la Radioterapia, en cualquiera de sus modalidades de administración, como el tratamiento idóneo; sin embargo, no está exenta de graves y penosas complicaciones. Cuando se ha logrado el control de la actividad neoplásica, resulta incongruente que los efectos adversos del tratamiento aplicado, sean más severos que los ocasionados por la enfermedad primaria. Desde 1958, se han registrado un total de 127 casos de pacientes que desarrollaron una Fístula Recto-Vaginal de origen actínico, durante el tratamiento radiante de un carcinoma de cuello uterino, en el Instituto de Oncología "Luis Razetti" de Caracas. A todas estas pacientes se les realizó alguna modalidad de tratamiento quirúrgico con miras a restablecer la continuidad del septum rectovaginal. La finalidad del tratamiento quirúrgico fue sustituir el tejido irradiado, sometido a una isquemia crónica, por un tejido sano. Para ello se consideró previamente, la derivación fecal mediante la realización de una Colostomía. Posteriormente, un procedimiento de reparación local, combinando técnicas de colpoplastia y migración de tejido viable no irradiado (Descenso o Pulthrough y/o Injerto pediculados). El grupo estudiado resultó ser muy heterogéneo, y al carecer de un protocolo reconocido para el manejo de las complicaciones actínicas, fue muy laborioso evaluar la efectividad de los tratamientos realizados. Sin embargo, se pudo apreciar una tendencia mayor a favorecer los tratamientos combinados para alcanzar los objetivos previstos en la reparación del septum rectovaginal irradiado. El éxito se logró sólo en 18 pacientes, no pudiendo demostrar la efectividad de los tratamientos realizados. Sin embargo, se pudo apreciar una tendencia mayor a favorecer los tratamientos combinados para alcanzar los objetivos previstos en la reparación del septum rectovaginal irradiado. El éxito se logró sólo en 18 pacientes, no pudiendo demostrar la efectividad de un único esquema terapéutico. Debemos concluir que la prevención del carcinoma del cuello uterino y de los efectos actínicos severos a consecuencia de su tratamiento, es primordial. El control local de la infección y la sustitución del tejido desvitalizado por el tejido no irradiado, es la maniobra terapéutica a seguir una vez establecida la fístula

Correlación endoscopico-histopatológica en el diagnóstico del linfoma gástrico: la experiencia de un instituto oncológico / Endoscopic-histological correlation in the diagnostic of gastric lymphoma: a cáncer institute experience

Entre las principales características del Linfoma Gástrico están la variada apariencia endoscópica y la dificultad del diagnóstico mediante biopsia endoscópica convencional. Para valorar este problema se analizó la experiencia de 15 años del Instituto Oncológico Luis Razetti. Se clasificaron las lesiones (10 casos) morfológicamente en: a) tipo exofítico 5/50 por ciento b) tipo infiltrante 5/50 por ciento. Endoscópicamente fue más difícil de valorar el tipo infiltrante en su categoría de pliegue grueso 2/20 por ciento, arrojando un 33 por ciento de diagnósticos benignos. Histopatológicamente el diagnóstico fue benigno el 66 por ciento de las veces y dudoso en el 33 por ciento. El tipo exofítico en su categoría de mamelón erosionado fue el segundo más difícil en el diagnóstico endoscópico e histopatológico. Cuando las anteriores categorías se asociaban a ulceraciones, los diagnósticos malignos se incrementaban. El 40 por ciento de los casos fueron a cirugía sin diagnóstico histopatológico de malignidad. Los 10 casos correspondieron a Linfoma No Hodgkin difuso de células grandes, diagnóstico alcanzado en una sola oportunidad preoperatoriamente. No hubo correlación entre la morfología tumoral y la invasión intraparietal. Sólo 3 pacientes sobrevivieron más de 1 año. Se puede concluir que el método de video endoscopia puede ayudar a mejorar el conocimiento del endoscopista en el diagnóstico del linfoma gástrico, mientras que la biopsia con aro de polipectomía, los colorantes como el Indigo Carmín y las técnicas especiales como la mucosectomía, ayudan a mejorar el diagnóstico histopatológico, ya que la biopsia convencional aporta muestras pequeñas y a menudo superficiales

Osteosarcoma del macizo craneofacial: experiencia en el Instituto de Oncología Luis Razetti, Caracas / Osteosarcoma of solid craniofacial: experience in the Institute of Incology Luis Razetti, Caracas

El Sarcoma Osteogénico es el tumor primario maligno más frecuente del hueso y relativamente raro en la región cráneo facial. el osteosarcoma de cráneo representa el 1.6 por ciento y los de maxilar y mandibula el 6,5 por ciento . Puede ser primario o secundario a Enfermedad de Paget o a Radioterapia. El síntoma y signo predominante es el aumento de vólumen, doloroso o no, del área afectada. El promedio de edad es de 38 años y sólo el 16 por ciento de los pacientes son menores de 13 años. No hay imagen radiológica característica. El pronóstico es desfavorable obteniéndose la mayor sobrevida en los pacientes con Osteosarcoma de mandíbula. En el IOLR en las ultimas 3 décadas, se han registrado 14 pacientes, con el Diagnóstico de Osteosarcoma localizado en el macizo craneofacial, de los cuales 9 son presentados en esta revisión. El promedio de edad fue de 20,6 años, 6 pacientes de sexo femenino y 3 del masculino. el síntoma predominante fue el aumento de volumen no doloroso en el área afectada, 8 pacientes consultaron previamente a odontólogo, 8 pacientes con tumor primario y 1 secundario a radioterapia por Retinoblastoma en ojo derecho. El tratamiento inicial en 3 pacientes fue radioterapia, en uno conjuntamente con quimioterapia. Dos de estos casos (Qt + Rt, y sola) fueron seguidos de cirugía y uno por Qt. En 2 pacientes el tratamiento primario fue cirugía seguido de radioterapia, luego quimioterapia en ambos casos. En 1 caso fue cirugía y otro fue tratado. un caso recibió 1 xiclo de quimioterapia sin control sucesivo. De los 9 pacientes, 2 con tumor en mandíbula tuvieron sobrevida libre de enfermedad hasta su último control a los 7 años y 5 murieron el primer año. El paciente con el osteosarcoma post radiación sobrevivió 2 años con enfermedad y actualmente existe otro paciente en tratamiento con quimioterapia neoadyuvante a quien ya se le realizó cirugía. en conclusión, el osteosarcoma del maciso craneofacial es un tumor sumamente raro asociado a una alta mortalidad independientemente de la terapéutica aplicada