Marine plastics alter the organic matter composition of the air-sea boundary layer, with influences on CO2 exchange: a large-scale analysis method to explore future ocean scenarios.

Microplastics are substrates for microbial activity and can influence biomass production. This has potentially important implications in the sea-surface microlayer, the marine boundary layer that controls gas exchange with the atmosphere and where biologically produced organic compounds can accumulate. In the present study, we used six large scale mesocosms to simulate future ocean scenarios of high plastic concentration. Each mesocosm was filled with 3 m3 of seawater from the oligotrophic Sea of Crete, in the Eastern Mediterranean Sea. A known amount of standard polystyrene microbeads of 30 µm diameter was added to three replicate mesocosms, while maintaining the remaining three as plastic-free controls. Over the course of a 12-day experiment, we explored microbial organic matter dynamics in the sea-surface microlayer in the presence and absence of microplastic contamination of the underlying water. Our study shows that microplastics increased both biomass production and enrichment of carbohydrate-like and proteinaceous marine gel compounds in the sea-surface microlayer. Importantly, this resulted in a ∼3 % reduction in the concentration of dissolved CO2 in the underlying water. This reduction was associated to both direct and indirect impacts of microplastic pollution on the uptake of CO2 within the marine carbon cycle, by modifying the biogenic composition of the sea's boundary layer with the atmosphere.

Global variability in seawater Mg:Ca and Sr:Ca ratios in the modern ocean.

Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth-ocean-atmosphere dynamic exchange of elements. The ratios' dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios' variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect.

Effect of acute and long-term administration of gold nanoparticles on biochemical parameters in rat brain.

The present study investigated stress oxidative parameters and activities of enzymes of the energy metabolism in various brain structures. Rats were subjected to acute and long-term administration of gold nanoparticles (GNPs) with mean diameters of 10nm and 30nm. Adult (60days old) male Wistar rats received a single intraperitoneal injection (acute administration; 70µg·kg-1) or repeated injections once daily for 28days (long-term administration; 70µg·kg-1) of saline solution or GNPs (10nm or 30nm). Twenty-four hours after administration of the final dose, the animals were killed and the cerebral structures were isolated for enzyme analysis. In this study, we observed that the thiobarbituric acid-reactive species and carbonyl protein levels were decreased after acute administration of GNPs, whereas the superoxide dismutase activity was increased after acute and long-term of GNPs. The catalase activity was affected by the administration of GNPs. Furthermore, we have not found change in the citrate synthase activity. The succinate dehydrogenase, malate dehydrogenase, complexes I, II, II-III and IV, and creatine kinase activities were altered. These results indicate that inhibition energy metabolism can be caused by oxidative stress.

Acute and chronic administration of gold nanoparticles cause DNA damage in the cerebral cortex of adult rats.

The use of gold nanoparticles is increasing in medicine; however, their toxic effects remain to be elucidated. Studies show that gold nanoparticles can cross the blood-brain barrier, as well as accumulate in the brain. Therefore, this study was undertaken to better understand the effects of gold nanoparticles on rat brains. DNA damage parameters were evaluated in the cerebral cortex of adult rats submitted to acute and chronic administration of gold nanoparticles of two different diameters: 10 and 30nm. During acute administration, adult rats received a single intraperitoneal injection of either gold nanoparticles or saline solution. During chronic administration, adult rats received a daily single injection for 28 days of the same gold nanoparticles or saline solution. Twenty-four hours after either single (acute) or last injection (chronic), the rats were euthanized by decapitation, their brains removed, and the cerebral cortices isolated for evaluation of DNA damage parameters. Our study showed that acute administration of gold nanoparticles in adult rats presented higher levels of damage frequency and damage index in their DNA compared to the control group. It was also observed that gold nanoparticles of 30nm presented higher levels of damage frequency and damage index in the DNA compared to the 10nm ones. When comparing the effects of chronic administration of gold nanoparticles of 10 and 30nm, we observed that occurred significant different index and frequency damage, comparing with control group. However, there is no difference between the 10 and 30nm groups in the levels of DNA damage for both parameters of the Comet assay. Results suggest that gold nanoparticles for both sizes cause DNA damage for chronic as well as acute treatments, although a higher damage was observed for the chronic one.

Management of pseudoaneurysm of the splenic artery: report of two cases.

BACKGROUND: Splenic pseudoaneurysm is an uncommon disease. It occurs as a consequence of injury to the vascular wall, mostly inflammatory. The main symptom is gastrointestinal bleeding. The objective of this paper is to present the case of two patients with splenic pseudoaneurysm. CASE REPORTS: The first case we present is a 26-year-old male with a history of idiopatic pancreatitis, pancreatic abscess and colonic fistula 3 years prior. The second case is a 20-year-old male with a history of chronic kidney disease with peritoneal dialysis interrupted due to fungal (Candida albicans) peritonitis. Both patients presented with signs of lower gastrointestinal bleeding. Endoscopic examinations (upper endoscopy and colonoscopy) were inconclusive. Tomographic studies showed the lesion. Arteriography with embolization was performed and was satisfactory in one case and partially satisfactory in the other case. Surgery was done with proximal and distal ligation of the lesion with splenectomy. Postoperative evolution was satisfactory. During the follow-up for 6 and 12 months, neither patient has presented signs of recurrent bleeding. CONCLUSIONS: This is a very rare lesion usually presenting after a history of pancreatitis or abdominal trauma. This lesion must be ruled out in patients with obscure gastrointestinal bleeding. Arteriography with embolization is the best diagnostic and probably therapeutic procedure. Surgery is warranted for hemodynamically unstable patients, embolization failure or rebleeding.

Systematic management of postoperative enterocutaneous fistulas: factors related to outcomes.

BACKGROUND: Most enterocutaneous fistulas are postoperative in origin. Sepsis, malnutrition, and hydroelectrolytic deficit are still the most important complications to which patients with postoperative enterocutaneous fistulas (PEF) are exposed. Knowledge of prognostic factors related to specific outcomes is essential for therapeutic decision-making processes. METHODS: We reviewed files of all consecutive patients with PEF treated in our hospital during a 10-year period. Our aim was to identify factors related to spontaneous closure, need for operative treatment, and mortality. Univariate and multivariate analyses were performed. RESULTS: A total of 174 patients were treated. The most frequent site of origin was the small bowel (90 patients: 48 jejunal, and 42 ileal), followed in frequency by the colon (50 patients). Postoperative enterocutaneous fistula closure was achieved in 151 patients (86%), being spontaneous in 65 (37%) and surgical in 86 (49%). Factors that significantly precluded spontaneous closure were jejunal site, multiple fistulas, sepsis, high output, and hydroelectrolytic deficit at diagnosis or referral. Origin of PEF at our hospital was the only factor significantly associated with spontaneous closure. The most frequent operative indication was PEF persistence without sepsis. Factors significantly associated with the need for operative treatment were high output, jejunal site, and multiple fistulas. Closure was achieved in 84% of patients who underwent operation. A total of 23 patients died (13%). Factors associated with mortality were serum albumin <3.0 g/dl (at diagnosis or referral), high output, hydroelectrolytic deficit, multiple fistulas, jejunal site, sepsis, and a complex fistulous tract. CONCLUSIONS: In spite of advances in management of PEF, the associated morbidity and mortality remain high. Among several variables influencing outcome, our multivariate analysis disclosed high output, jejunal site, multiple fistulas, and sepsis as independent adverse factors related to non-spontaneous closure, need for operative treatment, and/or death.

[Splenectomy incidence in a specialized care hospital]. / Incidencia de esplenectomías en un hospital de tercer nivel de atención.

BACKGROUND: splenectomy has been elected surgical procedure for multiple hematologic diseases, specially for Idiopathic Thrombocytopenic Purpura. The aim of this study was to compare the incidence of splenectomies in two different periods of time and to show decrease tendency during the most recent years. METHODS: it was a retrospectively reviewed study from medical records of patients who underwent splenectomy at the Hospital de Especialidades Siglo XXI, between 1986 to 1990 and 1995 to 1999. RESULTS: during the first period of time, the incidence of splenectomies for hospital admissions was 0.52%, and in the second 0.19%. CONCLUSIONS: the incidence of splenectomies performed at the Hospital de Especialidades Siglo XXI decreased in the second period of time, probably because there are new available treatments for hematologic diseases.

[Bariatric surgery for pseudotumor cerebri. Case report]. / Tratamiento del pseudotumor cerebri con cirugia bariátrica. Reporte de un caso.

INTRODUCTION: We report here a case of a patient with pseudotumor cerebri (PTC) associated with morbid obesity. PTC, also called benign intracranial hypertension, is a known complication of morbid obesity with resolution by reduction of obesity. CLINICAL CASE: A 42-year-old female with morbid obesity and secondary PTC underwent a modified jejunocolonostomy. RESULTS: The patient has lost 43% of excess body weight and the intracranial pressure is normal. CONCLUSIONS: PTC is a benign pathology, and the cause may be morbid obesity. Bariatric surgery is useful in the management of these patients for the resolution of this disease.

[Relaparotomy on demand: factors related to mortality]. / Relaparotomía a demanda. Factores asociados a mortalidad.

OBJECTIVE: To assess the mortality related factors of patients after relaparotomy on demand. BACKGROUND: In some patients, a relaparotomy after a primary laparotomy will be necessary, most due to acute complications. The relaparotomy can be planned or on demand based on the evolution of the patient. Which of these approaches is better is still a matter of debate. MATERIAL AND METHODS: Thirty three patients underwent relaparatomy on demand in a general surgery unit. RESULTS: Of 51 relaparotomies, 98% were positive. Nineteen of the 33 patients died, resulting in a mortality rate of 58%. The factors associated with mortality were development of an intestinal fistula (p < 0.02), wound infection (p < 0.03), generalized peritonitis in the primary surgery (p < 0.001), urgent primary laparotomy (p < 0.003), development of multiple organ failure (p < 0.005), and respiratory insufficiency (p < 0.01). CONCLUSIONS: Laparotomy on demand is useful in the treatment of patients with abdominal sepsis; however, the mortality is still very high.

[Intussusception in adults]. / Invaginación intestinal en adultos.

Intestinal intussusception in adults is a very rare entity whose etiology differs greatly from its pediatric counterparts. Three adult patients with intestinal intussusception presented with intestinal obstruction and required surgery for its resolution. In each case a pathologic cause was found. They had intestinal polyps, two benign (lipoma and hamartomatous polyps) and one malignant (metastasis). Intestinal intussusception in adults usually has a pathologic cause. About half have a malignant etiology. Intestinal resection without reduction of the intussusception is the preferred surgical procedure.

[Tuberculous psoas abscess in a patient with HIV]. / Absceso de psoas tuberculoso en paciente con VIH.

Psoas abscess is an uncommon disease with varied etiology. The most common pathogen in primary abscess is Staphylococcus aureus. Crohn's disease is the most common cause of a secondary abscess. Recently, drug abuse and HIV infection have become important risk factors in identification of a patient with psoas abscess. Mycobacterium tuberculosis is considered an extremely rare cause of psoas abscess, but it is reported in HIV patients. Physical presentation is insidious; classical symptoms are pain and fever. Computed tomography (CT) is the most important tool for diagnosis. Preferred treatment is percutaneous drainage guided by CT. Open surgical drainage should be reserved if percutaneous drainage fails, if possible by extraperitoneal approach; in secondary abscess, the transperitoneal approach is preferred to correct the possible disease.

[Abdominal pseudocyst in a patient with ventriculoperitoneal shunt. A case report]. / Pseudoquiste abdominal en paciente con derivación ventriculoperitoneal. Reporte de un caso.

Since 1905, the abdominal cavity has been used for absorption of cerebrospinal fluid in patients with hydrocephalus. Among complications in its use is formation of abdominal pseudocysts. We describe the case of a patient with hydrocephalus who developed an abdominal pseudocyst. The main complaint of the patient was abdominal pain and fever. During physical examination, a 15-cm abdominal tumor was detected. The patient underwent abdominal surgery for excision of the pseudocyst and peritoneal shunt was relocated to right atrium. Recovery was uneventful. Incidence of abdominal pseudocyst ranges from 1-4.5%. Principal symptoms are related with intracranial hypertension. The patient usually requires surgical exploration to resolve the illness, and in presence of infection the shunt should be changed.

[Enterocutaneous fistulas in patients older than 70 years]. / Fístulas enterocutáneas en pacientes mayores de 70 años.

INTRODUCTION: Enterocutaneous fistula remains a major complication after abdominal surgery. MATERIAL AND METHODS: We reviewed the charts of patients over 70 years of age with enterocutaneous fistula who were seen in a general surgery department. Special interest was given to mortality-related factors. RESULTS: A total of 19 patients were seen. The median age was 76 years. All fistulas were postoperative. All patients were managed based on the phases of Chapman and Sheldon. The most common site of presentation was colon, followed by jejunum and duodenal fistulas. More than half of the patients were malnourished at time of presentation. Spontaneous closure presented in eight patients (47%), seven other patients required surgical treatment for closure of their fistulas. Closure of the fistulas was obtained in 15 patients (79%). Four patients died resulting in a mortality rate of 21%. The factors against spontaneous closure were high output (p < 0.03), jejunal fistulas (p < 0.05), hydroelectrolytic imbalance (p < 0.01) and multiple fistulas (p < 0.02). The factors related to mortality were high output (p < 0.04), hydroelectrolytic imbalance (p < 0.02), jejunal fistulas (p < 0.04) and sepsis (p < 0.01). CONCLUSION: Patients > 70 years of age with enterocutaneous fistulas have the same mortality reported in the overall population. Sepsis remains the most important cause of death in patients with enterocutaneous fistulas.

[Frantz-Gruber tumor: a case report]. / Tumor de Frantz-Gruber: reporte de un caso.

OBJECTIVE: The objective of this report is to describe the existence of a rare tumor that must be taken into consideration when studying the diagnosis of pancreatic tumors. CASE REPORT: A 20-year-old female with abdominal pain as an only manifestation was seen. The diagnosis of a pancreatic head and body tumor was made. During surgery, we found a tumor in the head and body of the pancreas that measured approximately 10 x 7 cm; histopathologic study revealed a solid and cystic papillary epithelial neoplasm of the pancreas. DISCUSSION: Frantz-Gruber tumor is a rare pancreatic tumor suspected during the evaluation of a young female with abdominal pain and confirmed during surgery. It is important to consider the existence of this tumor in the evaluation of patients with these characteristics; even if the tumor's biological behavior is benign Frantz-Gruber tumor is considered a low-grade malignant tumor

[Management of the abdominal wall in sepsis. Comparison of two techniques]. / Manejo de la pared abdominal en sepsis. Comparación entre dos técnicas.

OBJECTIVE: To compare two techniques of open abdomen management in patients with abdominal sepsis. INTRODUCTION: Some patients with abdominal sepsis will require open abdomen management to avoid abdomen compartment syndrome. We compare use of the Bogota bag with a technique developed at our Institution with a subcutaneous polyethylene bag. METHODS: Thirty nine consecutive patients with abdominal sepsis who were managed with open abdomen. RESULTS: Twenty one patients with Bogota bag and 18 patients with subcutaneous polyethylene bag. Patients with Bogota bag had more report surgery intrabdominal complications compared with patients with subcutaneous polyethylene bag (p = 0.04, p = 0.037, respectively). Mortality was the same. CONCLUSIONS: Use of subcutaneous polyethylene bag in patient with abdominal sepsis and open abdomen appears safer when compared with Bogota bag.

[Gastrointestinal tuberculosis]. / Tuberculosis gastrointestinal.

INTRODUCTION: Intestinal tuberculosis usually is not contemplated as a possible cause of chronic abdominal pain; nevertheless, incidence of this disease is increasing even in well-developed countries. MATERIALS AND METHODS: Four patients with intestinal tuberculosis who required surgical treatment. RESULTS: All patients had a history of chronic abdominal pain, presented acute complications of the disease, and required surgery. Three patients had AIDS and the remaining patient had chronic renal failure. CONCLUSIONS: Intestinal tuberculosis is a disease that should be considered as possible cause of chronic abdominal pain in patients with altered immunology.