PubMed Health⌕ Search

Biomedical subjects

J A Marrero

Publications and source records attributed to J A Marrero.

11 recordsLinked to original sources
PubMed2006

Advances in critical care hepatology.

Complications of liver disease are commonly seen in the intensive care unit (ICU). When evaluating patients with liver disease in the ICU, it is important to determine whether it is acute or chronic liver disease. Because the pathophysiological mechanisms differ among acute and chronic liver, they will be consider separately in this review. Significant advances in the management of acute liver failure highlight the importance of intracranial pressure monitoring for Grade III/IV encephalopathy, and suggest that moderate hypothermia may be a promising treatment for these patients with refractory intracranial hypertension. Chronic liver disease is best discussed in terms of the various complications that may ensue such as ascites, hepatorenal syndrome, spontaneous bacterial peritonitis, variceal hemorrhage and hepatic encephalopathy. Each of these conditions will be discussed with specific attention to critical care management.

Ascites↗
PubMed2005

Relationship between diabetes mellitus and adenocarcinoma of the oesophagus and gastric cardia.

BACKGROUND: Obesity is a risk factor for adenocarcinomas of the oesophagus and gastric cardia. Diabetes mellitus might mediate that association. AIM: To estimate the risk of diabetes mellitus on the development of adenocarcinoma of distal oesophagus and gastric cardia beyond that of gastro-oesophageal reflux disease. METHODS: A case-control study was performed using a national administrative database of the Veterans Administration. RESULTS: A total of 311 cases of cancer and 10,154 controls were identified. Gender, age, and race were risks for cancer. Diabetes was diagnosed in 36% of cases, and 32% of controls (P = 0.15). Diabetic complications were diagnosed in 14% of cases and 13% of controls (P = 0.60). Multiple logistic regression confirmed the absence of an association between cancer and diabetes (odds ratio 1.1, 95% confidence interval 0.8-1.5) or diabetic complications (odds ratio 0.8, 95% confidence interval 0.6-1.3), adjusting for age, gender, and race. CONCLUSIONS: Within the limitations of this case-control study, there is no evidence of an association between diabetes and adenocarcinoma of the oesophagus or gastric cardia among US veterans with gastro-oesophageal reflux disease.

Adenocarcinoma↗
PubMed2001

Hepatocellular carcinoma.

The number of papers published regarding hepatocellular carcinoma between 1999 and 2001 increased from previous years. This year a study confirmed the increase in incidence in the United States. Also, several studies established for the first time that tobacco smoking was a risk factor for the development of this tumor. Several studies established that the process of angiogenesis is critical for the development of hepatocellular carcinoma, and one paper indicated that inhibiting this process might lead to possible treatment of this tumor. Resection was compared with liver transplantation for the first time in two studies. It was shown that transplantation offered the overall best long-term option, but in a certain group of patients without portal hypertension and well-preserved liver function resection is the best option.

Journal Article↗
PubMed2000

Endoscopic transpapillary drainage of pancreatic abscess: technique and results.

BACKGROUND: Pancreatic abscess is one of the serious complications of acute pancreatitis. Traditionally, pancreatic abscess has been treated by operative drainage. Based on experience with endoscopic transpapillary drainage of pseudocysts, a similar technique was used in patients with pancreatic abscess. METHOD: Patients were evaluated by endoscopic retrograde cholangiopancreatography. In those with pancreatic abscess communicating with the main pancreatic duct, pancreatic sphincterotomy, saline irrigation of the abscess cavity, and catheter dilation followed by 10F pancreatic stent placement were done. Instillation of gentamicin and nasopancreatic catheter drainage were used in difficult cases. RESULTS: Of 22 patients with pancreatic abscess, 11 underwent endoscopic transpapillary drainage with technical success in 10 patients (90%); 8 patients (74%) had resolution of pancreatic abscess, clinically and radiographically. Intracavitary instillation of gentamicin and nasopancreatic catheter drainage were used in 2 patients. Two patients in whom endoscopic transpapillary drainage failed underwent operative drainage with a favorable outcome, and the one patient in whom endoscopic treatment was technically unsuccessful underwent successful percutaneous drainage. One patient had mild pancreatitis. CONCLUSION: Endoscopic transpapillary drainage is an effective nonoperative therapy for selected cases of pancreatic abscess and is associated with minimal morbidity and no mortality.

Abdominal Abscess↗
PubMed2000

Dextran sulfate sodium-induced murine colitis activates NF-kappaB and increases galanin-1 receptor expression.

Galanin is widely distributed in enteric nerve terminals and acts to modulate intestinal motility by altering smooth muscle contraction. This ligand causes Cl(-) secretion when colonic epithelial cells express the galanin-1 receptor (Gal1-R) subtype. Because Gal1-R expression by colonic epithelia is upregulated by the transcription factor nuclear factor-kappaB (NF-kappaB), increasingly appreciated as critical in the pathophysiology of inflammatory bowel disease, we wondered whether the diarrhea associated with this condition could be due to NF-kappaB-mediated increases in Gal1-R expression. To test this hypothesis, we provided oral dextran sulfate sodium (DSS) to C57BL/6J mice. Although Gal1-R are not normally expressed by epithelial cells lining the mouse colon, DSS treatment resulted in increased NF-kappaB activation and Gal1-R expression. Whereas galanin had no effect on murine colonic tissues studied ex vivo, it progressively increased short-circuit current and colonic fluid secretion in DSS-treated mice. Concomitant parenteral administration of the NF-kappaB inhibitor dexamethasone attenuated the activation of this transcription factor by DSS, inhibiting the increase in Gal1-R expression. Although Gal1-R-specific antagonists do not exist, intracolonic administration of commercially available galanin antibody diminished the DSS-induced increase in colonic fluid accumulation. Overall, these data demonstrate that a significant component of the excessive fluid secretion observed in DSS-treated mice is due to increased Gal1-R expression.

Animals↗
PubMed1999

Human colonic epithelial cells express galanin-1 receptors, which when activated cause Cl- secretion.

Galanin is a peptide hormone widely expressed in the central nervous system and gastrointestinal (GI) tract. Within the GI tract galanin is present in enteric nerve terminals where it is known to modulate intestinal motility by altering smooth muscle contraction. Recent studies also show that galanin can alter intestinal short-circuit current (Isc) but with differing results observed in rats, rabbits, guinea pigs, and pigs. In contrast, nothing is known about the ability of galanin to alter ion transport in human intestinal epithelial tissues. By RT-PCR, we determined that these tissues express only the galanin-1 receptor (Gal1-R) subtype. To evaluate Gal1-R pharmacology and physiology, we studied T84 cells. Gal1-R expressed by these cells bound galanin rapidly (half time 1-2 min) and with high affinity (inhibitor constant 0.7 +/- 0.2 nM). T84 cells were then studied in a modified Ussing chamber and alterations in Isc, a measure of all ion movement across the tissue, were determined. Maximal increases in Isc were observed in a concentration-dependent manner around 2 min after stimulation with peptide, with 1 microM galanin causing Isc to rise more than eightfold and return to baseline occurring within 10 min. The increase in galanin-induced Isc was shown by 125I efflux studies to be due to Cl- secretion, which occurred independently of alterations in cAMP and phospholipase C. Rather, Cl- secretion is mediated via a Ca2+-dependent, pertussis toxin-sensitive mechanism. These data suggest that galanin released by enteric nerves may act as a secretagogue in the human colon by activating Gal1-R.

Calcium↗
PubMed1999

Azoxymethane-induced fulminant hepatic failure in C57BL/6J mice: characterization of a new animal model.

Without transplantation, approximately 50-90% of all patients with fulminant hepatic failure (FHF) die. This poor outcome is due in part to the absence of an appropriate animal model, which would allow for a greater understanding of the pathophysiology of this syndrome. Given the reports of liver injury in humans and livestock fed cycad palm nuts on the island of Guam, we hypothesized that the active ingredient azoxymethane (AOM) could cause FHF. We therefore evaluated AOM in C57BL/6J mice. Histologically, we observed microvesicular steatosis 2 h, sinusoidal dilatation 4 h, and centrilobular necrosis 20 h after AOM administration, and transmission electron microscopy showed that this agent causes mitochondrial injury. FHF was associated with all four stages of encephalopathy, as well as by a prodromal period of decreased eating and drinking lasting approximately 15 h before the development of stage I encephalopathy (i.e., loss of scatter reflex). Late encephalopathy was associated with increased arterial ammonia, decreased serum glucose, and evidence of brain edema (astrocyte swelling). We show that AOM-induced FHF is highly reproducible, without evidence of lot-to-lot variability, and is dose dependent. These findings therefore suggest that AOM is an excellent agent for the study of FHF, as well as indicate that Guamanian FHF may be due to AOM found in unwashed cycad palm nuts.

Animals↗
PubMed1999

Pathogenic Escherichia coli increase Cl- secretion from intestinal epithelia by upregulating galanin-1 receptor expression.

Galanin is widely distributed in enteric nerve terminals lining the human gastrointestinal (GI) tract. We have shown previously that galanin-1 receptors (Gal1-R) are expressed by epithelial cells lining the human GI tract, and upon activation cause Cl- secretion. Because expression of this receptor is transcriptionally regulated by nuclear factor-kappa B (NF-kappa B), which is activated by enteric pathogens as a part of the host epithelial response to infection, we investigated whether such bacterial pathogens could directly increase Gal1-R expression in the T84-cell model system. Pathogenic Escherichia coli, but not nonpathogenic E. coli, activate a p50/p65 NF-kappa B complex that binds to oligonucleotides corresponding to a recognition site located within the 5' flanking region of the human GAL1R gene. Pathogenic E. coli, but not normal commensal organisms, increase Gal1-R mRNA synthesis and [(125)I]galanin binding sites. Whereas galanin increases short-circuit current (Isc) approximately 5-fold in uninfected T84 cells, exposure to pathogenic, but not nonpathogenic, E. coli results in galanin increasing Isc approximately 20-fold. To confirm the validity of these in vitro observations, we also studied C57BL/6J mice infected with enterohemorrhagic E. coli (EHEC) by gavage. Infection caused a progressive increase in both NF-kappa B activation and Gal1-R expression, with maximal levels of both observed 3 days after gavage. Ussing chamber studies revealed that colons infected with EHEC, but not those exposed to normal colonic flora, markedly increased Isc in response to galanin. These data indicate that pathogen-induced increases in Gal1-R expression by epithelial cells lining the colon may represent a novel unifying pathway responsible for at least a portion of the excessive fluid secretion observed during infectious diarrhea.

Animals↗
PubMed1998

Electrophysiological characterization of human distal colon epithelium isolated using a novel technique.

Electrophysiological studies of human colonic epithelia traditionally have been hampered by the lack of tissue availability and by poor tissue quality. Human colonic epithelium is usually obtained surgically from individuals with underlying disease, while surgery itself can injure or alter the resected tissue. As a result, a wide range in electrophysiological parameters is reported in previous studies of human colonic epithelium. Such factors may also account for differences in measurements between humans and the few other species studied. We therefore devised a novel and rapid endoscopic technique, endoscopic mucosal resection (EMR), that allows for the removal and study of intestinal mucosal epithelium from normal volunteers. Using EMR we rapidly (7.2+/-2.4 min) isolated surgical-sized epithelial sheets from the distal colon (1.4+/-0.4 by 1.3+/-0.4 cm) that were readily mounted in a 0.64-cm2 Ussing chamber. We observed stable resistance (289+/-30 omega cm2), potential difference (1.6+/-0.6 mV), and I(SC)(24+/-9 microA/cm2) for at least 90 min, after which all experiments were terminated. Exposure to carbachol increased I(SC)2.2+/-0.5-fold, while forskolin increased I(SC) 4.4+/-0.5-fold. These data show that the electrophysiological characteristics of the human distal colon removed by EMR more closely approximate values reported for other mammals than when removed using other techniques. Thus EMR represents a significant advance over traditional techniques for isolating human tissues and will increase the availability of this tissue for future studies.

Aged↗
PubMed1995

Binocular interactions in rapid saccadic adaptation.

An adaptive mechanism controls the strength of innervation to the two eyes independently. However, under some circumstances an adjustment in strength of innervation to one eye is generalized to the other. The coupling and uncoupling of the two eyes during saccadic motor learning was studied using the technique of intrasaccadic target displacements to provide a precise visual-motor error proportional to the commanded movement. Early adaptive changes (saccade plus fast vergence) were measured within the saccadic interval and late adaptive changes (vergence error) were measured after the saccadic interval. When one viewing eye was retrained using intrasaccadic displacements, saccadic amplitude changes generalized to the other nonviewing eye. Thus, rapid adaptive changes trained monocularly were transferred to the nonviewing eye. But when two eyes were viewing and an adaptive stimulus was provided to only one eye (binocular viewing-monocular training), adaptive changes also occurred in both eyes. Experiments described here suggest that the recalibration of the saccade occurs quickly as a conjugate adjustment of gain which is used to balance innervation to the two eyes. Thereafter, disconjugate mechanisms provide a further recalibration to each eye independently.

Adaptation, Physiological↗