Molecular surveillance detects high prevalence of the neglected parasite Mansonella ozzardi in the Colombian Amazon.

Mansonellosis is an undermapped insect-transmitted disease caused by filarial nematodes that are estimated to infect hundreds of millions of people globally. Despite their prevalence, there are many outstanding questions regarding the general biology and health impacts of the responsible parasites. Historical reports suggest that the Colombian Amazon is endemic for mansonellosis and may serve as an ideal location to pursue these questions in the backdrop of other endemic and emerging pathogens. We deployed molecular and classical diagnostic approaches to survey Mansonella prevalence among adults belonging to indigenous communities along the Amazon River and its tributaries near Leticia, Colombia. Deployment of a loop-mediated isothermal amplification (LAMP) assay on blood samples revealed an infection prevalence of ∼40% for Mansonella ozzardi . This assay identified significantly more infections than blood smear microscopy or LAMP assays performed using plasma, likely reflecting greater sensitivity and the ability to detect low microfilaremias or occult infections. Mansonella infection rates increased with age and were higher among males compared to females. Genomic analysis confirmed the presence of M. ozzardi that clusters closely with strains sequenced in neighboring countries. We successfully cryopreserved and revitalized M. ozzardi microfilariae, advancing the prospects of rearing infective larvae in controlled settings. These data suggest an underestimation of true mansonellosis prevalence, and we expect that these methods will help facilitate the study of mansonellosis in endemic and laboratory settings.

Water stable isotopes reveal a complex rainfall to groundwater connectivity in central Honduras.

The inter-mountainous region of central Honduras has been experiencing abrupt urban drinking water shortages during the last decade. Land use fragmentation and rainfall deficits have rapidly reduced surface water quality and quantity in this region. Here we present a 3-yr (2018-2020) tracer study within the headwaters of the Choluteca River basin (2949 km2). We sampled rainfall (weekly N = 156; daily N = 270), drilled wells (N = 166; up to ~300 m depth), boreholes (N = 70; ~4-12 m depth), and springs (N = 128) to assess the spatiotemporal connectivity between rainfall and mean groundwater recharge elevations (MREs). Clear W-shaped incursions characterized rainfall isotopic seasonality from the dry to the wet season. Air mass back trajectory analysis revealed three primary moisture sources: 73 % (east, Caribbean Sea), 17 % (southwest, Pacific Ocean), and 10 % (north; Gulf of Mexico). Groundwater sources exhibited a strong meteoric origin with evidence of secondary evaporation evolution, characterized by low d-excess values. MREs for the drilled wells ranged from 821 to 2018 m asl with a mean value of 1570 ± 150 m asl. Seasonal isotopic variability during dry-wet transitions and the influence of rapid infiltration limited the performance of the MRE method in springs and boreholes. MREs coincided primarily with coniferous forests, pasture, and crop areas, within regions of moderate to high transmissivity. These results are intended to guide the mapping and delineation of critical recharge areas in central Honduras to enhance municipal water regulations, effective environmental protection, and long-term conservation practices.

COVID-19 conversations: A qualitative study of majority Hispanic/Latinx youth experiences during early stages of the pandemic.

Background: Growing evidence informs about the detrimental impact that COVID-19 has had on youths' mental health and well-being. As of yet, no study has directly examined the experiences and perspectives of children and young adolescents from racial and ethnic minority groups in the U.S., despite being exposed to more adversity, which may affect coping with the many challenges posed by the pandemic. Objective: This study aimed to give voice to a mostly Hispanic/Latinx group of youth regarding the impact of COVID-19 stay-at-home measures and to identify their emotional responses and coping strategies amid the pandemic in the U.S. when restrictions were at their hardest. Method: A total of 17 youths (70.6 % Hispanic; age range = 10-14 years; 52.9 % female) participated in four virtual semi-structured focus groups for each grade level (grades 5-8). Data was transcribed and analyzed using a gold standard thematic analysis approach. Results: Seven themes were identified concerning the impact of COVID-19, centering around the impact of racism, loss of income, the role of community and family in coping with stress, information overload, home-schooling, loneliness and boredom, and lack of structured routines. Conclusions: Our findings suggest that cultural factors (e.g., collectivism and familism) in Hispanic communities may offer important buffering during COVID-19. Future research studies evaluating the implementation of structured programs that provide a space to talk about emotions and thoughts related to the impact of the pandemic and training in strategies to cope with distress during mandatory home-schooling are needed.

Sharp Morphological Transitions from Nanoscale Mixed-Anchoring Patterns in Confined Nematic Liquid Crystals.

Liquid crystals are known to be particularly sensitive to orientational cues provided at surfaces or interfaces. In this work, we explore theoretically, computationally, and experimentally the behavior of liquid crystals on isolated nanoscale patterns with controlled anchoring characteristics at small length scales. The orientation of the liquid crystal is controlled through the use of chemically patterned polymer brushes that are tethered to a surface. This system can be engineered with remarkable precision, and the central question addressed here is whether a characteristic length scale exists at which information encoded on a surface is no longer registered by a liquid crystal. To do so, we adopt a tensorial description of the free energy of the hybrid liquid-crystal-surface system, and we investigate its morphology in a systematic manner. For long and narrow surface stripes, it is found that the liquid crystal follows the instructions provided by the pattern down to 100 nm widths. This is accomplished through the creation of line defects that travel along the sides of the stripes. We show that a "sharp" morphological transition occurs from a uniform undistorted alignment to a dual uniform/splay-bend morphology. The theoretical and numerical predictions advanced here are confirmed by experimental observations. Our combined analysis suggests that nanoscale patterns can be used to manipulate the orientation of liquid crystals at a fraction of the energetic cost that is involved in traditional liquid crystal-based devices. The insights presented in this work have the potential to provide a new fabrication platform to assemble low power bistable devices, which could be reconfigured upon application of small external fields.

Liquid-crystal-mediated self-assembly at nanodroplet interfaces.

Technological applications of liquid crystals have generally relied on control of molecular orientation at a surface or an interface. Such control has been achieved through topography, chemistry and the adsorption of monolayers or surfactants. The role of the substrate or interface has been to impart order over visible length scales and to confine the liquid crystal in a device. Here, we report results from a computational study of a liquid-crystal-based system in which the opposite is true: the liquid crystal is used to impart order on the interfacial arrangement of a surfactant. Recent experiments on macroscopic interfaces have hinted that an interfacial coupling between bulk liquid crystal and surfactant can lead to a two-dimensional phase separation of the surfactant at the interface, but have not had the resolution to measure the structure of the resulting phases. To enhance that coupling, we consider the limit of nanodroplets, the interfaces of which are decorated with surfactant molecules that promote local perpendicular orientation of mesogens within the droplet. In the absence of surfactant, mesogens at the interface are all parallel to that interface. As the droplet is cooled, the mesogens undergo a transition from a disordered (isotropic) to an ordered (nematic or smectic) liquid-crystal phase. As this happens, mesogens within the droplet cause a transition of the surfactant at the interface, which forms new ordered nanophases with morphologies dependent on surfactant concentration. Such nanophases are reminiscent of those encountered in block copolymers, and include circular, striped and worm-like patterns.

Liquid crystal mediated interactions between nanoparticles in a nematic phase.

A continuum theory is used to study the interactions between nanoparticles suspended in nematic liquid crystals. The free energy functional that describes the system is minimized using an Euler-Lagrange approach and an unsymmetric radial basis function method. It is shown that nanoparticle liquid-crystal mediated interactions can be controlled over a large range of magnitudes through changes of the anchoring energy and the particle diameter. The results presented in this work serve to reconcile past discrepancies between theoretical predictions and experimental observations, and suggest intriguing possibilities for directed nanoparticle self-assembly in liquid crystalline media.

Asymptomatic true gallbladder duplication: a case report and review of the literature.

Gallbladder duplication is a rare event, with an incidence at autopsy of about 1/4000, with very few documented symptomatic cases reported. Preoperative diagnosis and differentiation of this malformation are important to prevent inadvertent damage to the biliary system, a complicated postoperative course, and repeat surgery. We present a case of true gallbladder duplication found incidentally during abdominal ultrasonography (US). The diagnosis was made with US and the Y-type duplication was demonstrated with magnetic resonance cholangiopancreatography (MRCP).

[Hirschsprung disease in the adult. Report of a case]. / Enfermedad de Hirschsprung en el adulto. Informe de un caso.

OBJECTIVE: To describe a case of Hirschsprung's disease (HD) in an adult patient. BACKGROUND: HD is diagnosed in the newborn in 80 to 90% of cases. HD is rare in the adult, and usually affects an ultrashort segment of the bowel. CASE REPORT: A 49-year-old woman with a history of constipation since birth is involved. She was submitted to an abdominal laparotomy because of fecal impaction. A colostomy was performed. The diagnosis of HD affecting, the descending colon was established with manometry and histopathology. She underwent surgery, and a proctectomy and left hemicolectomy with colo-anal anastomosis was performed. CONCLUSION: Adult HD is an infrequently diagnosed entity that must be suspected in a patient with chronic, intractable constipation from infancy, evidence of megacolon, and typical manometric and histopathologic features. The short and ultrashort-segment disease are more often found in older children and adults. The differential diagnosis includes idiopathic megarectum, functional constipation, and colonic pseudo-obstruction.

Selective shunts for portal hypertension: current role of a 21-year experience.

The results of treatment of hemorrhagic portal hypertension with selective shunts over a 21-year period in a selected patient population are reported. Patients selected for surgical treatment had good cardiopulmonary and renal function, and most also had adequate liver function (141 Child-Pugh class A, 59 class B). Among 734 patients treated surgically for bleeding portal hypertension, 221 had selective shunts (168 distal splenorenal and 53 splenocaval shunts). Global operative mortality (in the 21-year period) was 14% and 12% for Child-Pugh A patients. Operative mortality in Child-Pugh A patients in the last 5 years was only 5%. The rate of rebleeding was 6%, rate of incapacitating encephalopathy was 5%, and rate of survival was 65% at 15 years (last 5 years: 88% at 1 year and 85% at 5 years). Good quality of life was demonstrated in 80% of surviving patients. Shunt patency was 94%. Postoperative portal blood flow changes occurred in 23% of cases (8% diameter reduction, 14% thrombosis). Compared with other forms of therapy (pharmacotherapy, sclerotherapy, and transjugular intrahepatic shunting), only liver transplantation offers similar results for these patients. In countries in which liver transplantation is not routinely performed, shunting with selective shunts is the treatment of choice for patients with good liver function.

[Endocrine tumors of the pancreas]. / Tumores endocrinos del páncreas.

BACKGROUND: Endocrine tumors of the pancreas arise from pancreatic and duodenal neuroendocrine cells. OBJECTIVE: To review clinical features, diagnosis and treatment of endocrine tumors of pancreas, as well as our experience at the Instituto Nacional de la Nutrición "Salvador Zubirán" (INNSZ). RESULTS: Endocrine tumors of pancreas are slow growing tumors. The most frequent tumors are insulinoma, gastrinoma and non-functioning tumors. Clinical picture of functioning tumors is determined by the action of the secreting hormone, and the diagnosis is established once high levels of the tumor secretin peptide are demonstrated. In order to localize the tumor and to search for metastasis, several imaging studies have been used. In general, image studies have demonstrated poor sensitivity in finding the primary lesion. Recently, dynamic studies have shown their ability to regionalize the peptide increase. Endoscopic and intraoperative ultrasound have shown promising results. Surgical resection is the only curative treatment, resection of hepatic metastasis can even improve survival. In the INNSZ, 38 patients with endocrine tumors of the pancreas have received initial treatment in a 32-year period. The most common neoplasia is the insulinoma, followed by non-functioning tumors and gastrinoma. Most insulinomas were benign, where as the malignancy rate of non-functioning. CONCLUSIONS: Endocrine tumors of the pancreas are rare lesions, with a variety of clinical pictures related to the hormone produced. Localizing studies are generally poor. Favorable outcome meaning cure of benign lesions or long survival despite the presence of malignancy occur in most patients.

Angiographic evaluation after portal blood flow preserving operations.

We carried out a prospective study comparing postoperative portal angiographic characteristics in patients with hemorrhagic portal hypertension treated electively by two different portal blood flow preserving procedures. Between 1986 and 1991, a total of 81 patients underwent operation: 38 selective shunts and 43 Sugiura-Futagawa procedures. Cirrhosis was shown by biopsy in 50 cases, 26 of them secondary to alcoholism. We found rebleeding in 5% of the patients, incapacitating postoperative encephalopathy in 8%, and an operative mortality of 7%. Fifty-two cases were evaluated in the postoperative period with angiography; 21 patients treated with a Sugiura-Futagawa operation were excluded due to portal vein thrombosis shown in the preoperative studies. Postoperative portal vein thrombosis was found in 11 cases (21%) [seven cases in the Warren group (21%) and four cases in the Sugiura-Futagawa group (20%)]. Decreased portal vein diameter was seen in eight cases (15%). The two procedures maintained hepatopedal portal blood flow, and no change was seen in relation to the preoperative state in 66% of the operated patients. We found no significant differences between the two procedures. Selection of procedure depends on the individual characteristics of each patient.

[Endoscopy and laparoscopy in the treatment of lithiasic cholecystitis associated with benign bile duct obstruction]. / Endoscopía y laparoscopía en el tratamiento de la colecistitis litiásica asociada a obstrucción benigna de vía biliar.

OBJECTIVE: To analyze the efficacy of a combined approach using ERCP plus laparoscopic cholecystectomy in the treatment of gallstones associated to benign common bile duct obstruction. DESIGN: Prospective study. SETTING: Tertiary-care medical center. PATIENTS: From a total of 270 laparoscopic cholecystectomies performed between October 1991 and January 1994, a group of 25 patients in whom preoperative ERCP was performed to rule out bile duct obstruction was selected for analysis. RESULTS: Choledocholithiasis was documented in nine patients (36%). In eight of them, stones were retrieved by ERCP. The diagnosis of odditis was established in five patients and a papilotomy was performed. The entire bile duct was normal in 11 cases. All patients in whom the common bile duct was normal, or cleared endoscopically, underwent laparoscopic cholecystectomy uneventfully. There was one complication of papilotomy. Duodenal perforation occurred in one patient who ultimately died. CONCLUSION: The combined approach using ERCP followed by laparoscopic cholecystectomy seems to be adequate for the treatment of gallstones associated to bile duct obstruction.

Elective treatment of bleeding varices with the Sugiura operation over 10 years.

A 10-year experience with the devascularization operation described by Sugiura is reported here. The operation was performed electively in 100 patients in whom it was not possible to place a shunt, all of whom had different kinds of hepatopathies (63 Child's A, 32 Child's B, and 5 Child's C). In 15 patients, the procedure was done in one stage (6% operative mortality, 1 patient), and, in 51, it was performed in two stages. Eight deaths were recorded in the 63 patients of the Child's A group, with a total of 111 operations. The operative mortality rate for this group was 12% and, as related to the number of operative procedures, 7% (8 of 111 operations). Seventeen patients were not considered for a second stage. Rebleeding in the early postoperative period was 4% and at long-term 6%. Incapacitating encephalopathy was found in 2 of the 71 surviving patients (3%). Survival (as determined by Kaplan-Meier tests) was 75% (1 year), 70% (5 years), and 69.2% (10 years). Six esophageal fistulas were observed secondary to transection. The Sugiura operation is an excellent complement to the therapeutic armamentarium used to treat portal hypertension, with low rebleeding and encephalopathy rates.

Colorectal variceal bleeding in patients with extrahepatic portal vein thrombosis and idiopathic portal hypertension.

We report three patients with colonic variceal bleeding secondary to portal hypertension, 0.5% of all cases with hemorrhagic portal hypertension studied by us in the last 16 years. One patient had idiopathic portal hypertension, and the others had extrahepatic portal vein thrombosis. Colonic varices were documented in all three cases by angiogram; large arteriovenous fistulas in the territory of the superior mesenteric artery and between the inferior mesenteric artery and hemorrhoidal veins were demonstrated in one patient. Two patients underwent colonoscopy; colonic varices were seen in only one. Two patients also had bled from esophagogastric varices. One patient underwent descending colon and sigmoid resection after failure to control bleeding with ligation of arterial supply; one patient underwent the Sugiura procedure, plus transanal ligation of hemorrhoids and rectal varices. At 3 months, 2 years, and 4 years of follow-up, the patients were in good general condition without any evidence of rebleeding.

Intermittent changes in portal venous flow in relation with spleno-pancreatic collaterals--"the pancreatic siphon"--after a selective shunt in a patient with idiopathic portal hypertension: case report.

The case of a patient with idiopathic portal hypertension who was subjected to a selective shunt because of variceal bleeding is reported. Large pancreatic collaterals--the pancreatic siphon--were documented 2 years after the operation with loss of portal flow. At 14 years of follow-up, the pancreatic collaterals have disappeared gradually with normalization of portal venous flow in spite of patency of the shunt.

[Hepatic abscess: image-guided percutaneous drainage. Technique and indications]. / Absceso hepático: drenaje percutáneo guiado por imagen. Técnica e indicaciones.

Six patients underwent image-guided percutaneous drainage of liver abscesses at the Instituto Nacional de la Nutricion (a tertiary care referral center in Mexico City) in a seven month period. These patients were closely followed in order to evaluate appropriate indications for percutaneous drainage as well as techniques, complications and clinical evolution. Our study group included five males and one female; their mean age was 44.4 years (28-63) and the mean hospitalization time 24.3 days (10-34). We found multiple liver abscesses in three patients, and solitary abscesses in three, two in the left lobe and one in the right lobe. Considering the largest diameter, mean abscess size was 13.7 cm. The most important clinical symptoms were: fever, abdominal pain and malaise, and the most significant laboratory abnormalities were anemia, hypoalbuminemia, leukocytosis and high alkaline phosphatase serum levels. Etiology could be determined in three cases, two were pyogenic abscesses and one amebic. Percutaneous drainage was successful in five out of our six patients (83.3%). Complications included one subcapsular hematoma, without hemodynamic consequences, and one patient with severe upper gastrointestinal tract hemorrhage who required surgery, but we could not entirely demonstrate that the bleeding episode was directly related to the percutaneous drainage.

The Sugiura procedure for patients with hemorrhagic portal hypertension secondary to extrahepatic portal vein thrombosis.

The Sugiura procedure (SP) was performed upon 27 patients with hemorrhagic portal hypertension secondary to extrahepatic portal vein thrombosis (EPVT) without associated hepatic disease. There were 14 female and 13 male patients. The mean age was 28 +/- 14 years. The causes of EPVT were protein C deficiency in two; antithrombin III deficiency in one patient, a history of omphalitis in two patients, a history of pancreatitis in one patient and idiopathy in 21 patients. The SP was completed in two surgical stages in 14 patients and in one stage in nine. There was one operative death. One patient had mild postoperative encephalopathy, and two patients rebled at long term follow-up study. Actuarial survival rate was 82 per cent at five and ten years. It is concluded that the SP is a good alternative for the management of hemorrhagic portal hypertension secondary to EPVT.

[Idiopathic portal hypertension]. / Hipertensión portal idiopática.

Patients with portal hypertension without a demonstrable cause have been reported in the literature under several different terms, such as tropical splenomegaly, phlebosclerosis, obliterative portal venopathy of the liver, hepatoportal sclerosis, noncirrhotic portal fibrosis and idiopathic portal hypertension (IPH). Such patients have been described worldwide, with a greater frequency in India and Japan. The etiology of IPH is still unknown, although some of the theories that have been proposed are: exposure to toxic substances or drugs, relationship with the hepatitis-B virus, immunologic abnormalities, systemic or intra-abdominal infections and clotting abnormalities. The main histopathologic findings are periportal fibrosis, obliteration of small portal veins and sclerosis of the interhepatic portal system. Although these abnormalities could be secondary to portal hypertension, it has been proposed that the vascular changes are the primary event that leads to portal hypertension. The site of increased resistance in IPH is found at the presinusoidal level with some component at the sinusoidal and postsinusoidal level. The main symptoms and signs in IPH are upper gastrointestinal tract bleeding secondary to esophago-gastric varices, symptoms related to anemia, and splenomegaly. The long-term prognosis for patients with IPH is better than for cirrhotic patients, with a 77% survival at ten years. Variceal bleeding is the main cause of death, and some treatment to prevent bleeding or its recurrence is warranted. Although no comparative trial has been performed in IPH patients, the surgical management could be the first choice for elective treatment in these patient without liver failure, because of the high re-bleeding rates with chronic sclerotherapy. Pharmacologic management could be considered for prophylactic treatment of these patients.