Renal excretion of endothelin in children

Endothelin (ET) is a peptide with profound vasoconstrictive potential. First isolated from porcine endothelial cell supernatant, it is produced also by smooth muscle, epithelial and circulating cells. Besides vasoconstriction, a wide spectrum of biological activities of ET (via activation of membrane receptors) has been described. These include regulation of other hormones and neurotransmitters, cellular growth and proliferation, bronchoconstriction, and, in the kidney, natriuresis and water diuresis. ET exerts its effects mainly in an autocrine and paracrine fashion. A high concentration of ET is found in urine, compared with plasma originating mainly from the kidney itself. In this review we focus on the role of urinary excretion of ET in children. ET excretion was determined under different physiological and pathological conditions. In premature infants and newborns, the daily excretion of ET (corrected for body surface) was higher than in older children; it was constant, and comparable to the values in healthy adults after the age of 2 years. Renal ET excretion correlated positively with urine flow in both healthy and sick children. Conditions with tubular and/or collecting duct cell damage, such as severe hypoxia, hemolytic-uremic syndrome, renal transplantation, diabetes mellitus, chronic renal failure, and contrast media cytotoxicity were characterized by elevated urinary excretion of ET. In conclusion, the renal excretion of ET is influenced by several factors, probably reflecting the intrarenal ET production. ET has a low specificity with regard to renal injury.     

Hemolytic uremic syndromes in childhood

The hemolytic uremic syndrome (HUS) comprises hemolytic anemia, acute renal failure, and thrombocytopenia. It is the most frequent cause of acute renal failure in childhood. Ninety percent of the patients have a diarrheal prodrome, and are referred to as having typical HUS. Approximately 10% exhibit the so-called atypical HUS. Typical HUS is caused by shigatoxin-producing Escherichia coli. The toxin, bound to the globotriosyl ceramide cell receptor and internalized, interferes with protein synthesis, predominantly of endothelial cells. The main target is the kidney, but nearly every organ system can be involved. The most common extrarenal involvement is damage to the central nervous system. The central event is probably an insult to the endothelial cell with consecutive loss of antithrombogenic properties. The von Willebrand factor, activation of platelets via platelet-activating factor, other growth factors (e.g., interleukins 1, 6, 8), nitric oxide, lipopolysaccharides, activated polymorphonucleated neutrophils, and the metabolites of the arachidonic acid cascade (e.g., prostaglandin I2) are believed to be involved in the pathogenic cascade. Controlled therapeutic trials with heparin, dipyridamole, aspirin, and urokinase have not been associated with improved outcome. Antibiotics have not yielded any benefit. Plasma infusions and plasma exchange appear to be efficacious, and are justified in cases of atypical HUS and thrombotic thrombocytopenic purpura. Binding of the toxin to the intestinal lumen, and thereby inhibition of enteral reabsorption, is under investigation.     

Concurrent primary carcinoma of the gallbladder and acute cholecystitis

BACKGROUND/AIMS: Primary carcinoma of the gallbladder is rare and associated with a late diagnosis and poor prognosis. Concurrent acute cholecystitis frequently obscures the presence of carcinoma. The information regarding gallbladder carcinoma with acute cholecystitis is limited. In order to better understand the presentation of gallbladder carcinoma with acute cholecystitis, we retrospectively reviewed the data of patients with primary carcinoma of the gallbladder. METHODOLOGY: The data of 86 patients with primary carcinoma of the gallbladder treated between 1979 and 1994 were compiled and reviewed. The patients were divided into 2 groups: Group 1 (with acute cholecystitis, 21 patients) and Group 2 (without cholecystitis, 65 patients). Clinicopathological comparisons were made and evaluated between these two groups RESULTS: The average age of Group 1 patients was older than that of Group 2 patients (75+/-2 years vs. 63+/-2 years; p<0.05). Three Group 1 patients presented with sepsis. The interval between the onset of symptoms and hospital admission in Group 2 patients was significantly (p<0.05) longer than that in Group 1 patients (243+/-95 days vs. 20+/-11 days). Leukocytosis (>11,000/mm3) was more common in Group 1 patients than in Group 2 patients (47.6% vs. 15.4%). Jaundice was more common in Group 2, and fever was common in Group 1. The majority of Group 2 gallbladder cancers were stage V (75.4%). In contrast, 52.4% of Group 1 gallbladder cancers were stage III and 38.1% were stage V. The 30-day postoperative mortality rate in Group 1 and Group 2 patients was 9.5% and 7.7%, respectively. The cumulative survival of Group 1 patients was not different from that of Group 2 patients (log-rank test, p>0.05). CONCLUSIONS: Age, the interval of symptoms prior to admission, the location of abdominal pain, fever, leukocytosis, and the absence of jaundice suggested the presence of acute cholecystitis in gallbladder carcinoma. A high index of suspicion of the disease, intraoperative examination of gallbladder specimens, and more aggressive surgical treatment may improve patient survival.     

Malignant melanoma in the small intestine

A case story of malignant melanoma is presented. The tumour was localised to the jejunum. The symptoms, diagnosis and treatment are described and the pathogenesis is discussed.     

The P300 component of the auditory evoked potential in the posttraumatic vegetative state

The dynamic studies of P300 component of the acoustic evoked potential were conducted in 12 patients in posttraumatic state of the autonomic system. The amplitude and time parameters of P300 were analyzed, its spatial distribution over the cortex, and features of generation. The obtained results were compared with the normative data. Significant changes in P300 in comparison with the normal characteristics were revealed in patients with the absence of conscious mental activity. These changes were maximally expressed when the state of patients was irreversible. In case of patients' outcome from the studied state the amplitude-temporal and topographic response characteristics tended to normalization but did not reach it completely. The obtained results allow us to consider the P300 component as one of the most informative indices in consciousness recovery after severe brain injury.     

Increased living donor volunteer rates with a formal recipient family education program

As part of our ongoing studies to characterize molecular alterations in a well-defined series of surgically resected esophageal cancers, we examined the expression of 2 ras-regulated genes, whose products (osteopontin and cathepsin L) previously were shown to be associated with tumor invasion and metastasis. RNA was extracted from primary esophageal tumors (adenocarcinomas, 19; squamous-cell carcinomas, 6) and matched histologically normal esophageal mucosa from the distant resection margin. Northern analysis was used to quantitate RNA, relative to an 18S rRNA control, and immunohistochemistry to assess the tissue distribution of osteopontin. In addition, H-, K- and N-ras mutations were studied in the same tissues using PCR and hybridization with allele (mutant)-specific oligonucleotide probes. We demonstrated a K-ras mutation (codon 12, GTT) in one esophageal adenocarcinoma. The ras-regulated gene osteopontin was over-expressed in 100% of squamous-cell carcinomas and in 58% of adenocarcinomas relative to matched normal esophageal mucosa. Patterns of immunoreactivity for osteopontin protein also varied between squamous-cell carcinomas (tumor cell staining) and adenocarcinomas (predominantly tumor-infiltrating macrophages). Expression of cathepsin L also varied with esophageal tumor histology, with over-expression in 58% of primary esophageal adenocarcinomas and 33% of squamous-cell cancers.