Analysis of complications of endoscopic sphincterotomy for biliary stones in a consecutive series of 546 patients

BACKGROUND

Endoscopic sphincterotomy (ES) plays an important role in treatment of biliary stones; however, there remain some controversies concerning complications of ES, which in most cases seem not to be predictable.

METHODS

The aim of this study was a retrospective analysis of complications in 546 consecutive patients (267 males, 279 females, average age 63.7 years) who underwent endoscopic retrograde cholangiography (ERCP) for biliary stones from 1988 to 1995.

RESULTS

ES was performed in 535 patients (98%), and extraction of stones was successful in 493 (92%). In all, 29 complications (5.4%) were observed, including bleeding 13, cholangitis seven, cholecystitis four, pancreatitis three, retroduodenal perforation two; of these, four (14%) required an operation. Overall mortality was 0.3%.

CONCLUSION

While a significant decrease of the incidence of complications was observed in the course of the study, due to constantly improving experience, no correlation between risk factors and complications was identified.

The relationships among stem cells, crypts, and villi in the small intestine of mice as determined by mutation tagging

The number of stem cells that maintain a crypt of the small intestine is uncertain. Although the number of stem cells per crypt had been thought to be 10-20, current estimates indicate a much smaller number, possibly 1 stem cell per crypt. We report here that in SWR and C57BL/6 X SWR F1 mice, the results of mutation tagging are inconsistent with the existence of more than one stem cell per crypt. Mutations at the Dlb-1 locus mark the progeny of a single epithelial stem cell in the small intestine and reveal the size of the mutant clone. The epithelial cells are produced in the crypts and migrate up the villi to be sloughed off at the tip so that a mutant clone takes the form of a ribbon on the villus. Because the size of the mutant clones must be inversely proportional to the number of stem cells contributing to the villus, this provides a means of counting the stem cells (ethylnitrosourea was used to induce mutations in the intestine). In the duodenum the ribbons average 0.099 +/- 0.004 villus circumferences, indicating that there are 1/0.099 = 10.2 stem cells per villus. Because there are 10.5 +/- 0.67 crypts/villus, the estimate gives 10.2/10.5 = 0.97 +/- 0.1 stem cells/crypt. Because each crypt must have at least one stem cell, the vast majority can have only one stem cell and very few may have two or more.

ERCP in the era of laparoscopic biliary surgery. Experience with 407 patients

BACKGROUND

The combined endoscopic and laparoscopic treatment of biliary stones is now highly debated, especially as regards possible complications compared to one-step laparoscopic treatment.

METHODS

This study analyzes 407 cases (116 males, 291 females, average age 49 years, range 2-87) observed in the period from May 1991 to July 1994. All patients were evaluated preoperatively for the presence of biliary stones. Considering clinical presentation, blood analysis, ultrasonography, and medical history, 99 patients (24%) were selected for preoperative endoscopic retrograde cholangiopancreatography (ERCP). One patient refused preoperative ERCP.

RESULTS

Thirty-nine patients (40%) were found to have biliary stones and were submitted to therapeutic endoscopic sphincterotomy (ES). Endoscopic clearance of the bile ducts was achieved in all patients, with one complication (pancreatitis). In performing laparoscopic cholecystectomy, no technical difficulties could be attributed to ERCP, nor were there any conversions in patients who had had preoperative ERCP. Average postoperative hospital stay was 2.5 days. During a follow-up period of from 2 to 39 months, we diagnosed three patients (0.7%) with symptomatic residual stones. They were submitted to successful ERCP and extraction of the stones.

CONCLUSIONS

We conclude that ERCP offers an accurate preoperative selection of patients, allows for effective planning of treatment, and simplifies laparoscopic surgery.

Why do stem cells exist?

Self-renewing tissues have a differentiation hierarchy such that the stem cells are the only permanent residents of the tissue, and it is in these cells that most cancerous mutations arise. The progeny of the stem cells either remain stem cells or enter a transient proliferating cell population that differentiates to produce the functional cells of the tissue. The reason that this differentiation hierarchy exists has not been established. We show here that alternative hierarchies, in which there would be no stem cells, are feasible and biologically plausible. We show that current evidence from somatic mutation frequencies at both transgenic and endogenous loci implicates cell division in the origin of most somatic mutations. We suggest, therefore, that the existence of stem cells is an evolutionary consequence of a selective pressure to avoid cancer by reducing the number of somatic mutations. The stem cell hierarchy reduces the number of cell divisions of those cells that reside permanently in the tissue, which reduces the number of somatic mutations and thus minimizes the cancer rate. In the small intestine, the existence of stem cells reduces the mutant frequency in the stem cells by about one order of magnitude. Since two or more mutations are required to transform a cell, the protective effect may be 100-fold or more. Similar factors may be expected in other tissues.

A test for neutrality of mutations of the lacZ transgene

Neutral mutations are stable alterations in DNA that are neither beneficial nor damaging to the cell. Once a mutation is fixed in the DNA, the mutant frequency should increase to its maximum and plateau thereafter, provided that enough expression time is given. Evidence has been obtained indicating neutrality for the endogenous Dlb-1 locus and for the lacl in the BigBlue transgenic system, and is reported here for lacZ in the Muta Mouse system. We have found that, after an acute dose of ethylnitrosourea (ENU, 250 mg/kg) the mutant frequency for both lacZ transgene and Dlb-1 remained constant between 10 and 70 days after mutagenesis in the small intestine, where cell turnover is rapid (approximately 7 days). The same concept should apply to other tissues.

The induction of dominant somatic mutations at the Dlb-1 locus

In the small intestine of heterozygous mice (Dlb-1b/Dlb-1a), the Dlb-1b allele results in a stainable epithelium. The mutation or loss of the dominant Dlb-1b allele in a stem cell results in a non-staining ribbon of cells on a villus of the small intestine. To determine if dominant mutations resulting in the gain of staining--the induction of a Dlb-1b-like allele--could also be detected, we examined Dlb-1a homozygous mice (SWR) 2 weeks after a single treatment with 250 mg/kg ethylnitrosourea. Mutations to the dominant allele should appear as brown ribbons on unstained villi. Such ribbons were observed in the treated group but not in controls. The mutant frequency was low compared to the frequency of Dlb-1a-like mutations reported at the Dlb-1b allele in heterozygous mice.

HIV-1 isolates from children with or without AIDS have similar in vitro biologic properties

OBJECTIVE

To compare biologic properties of HIV-1 isolates from children with and without AIDS as a measure of viral cytopathogenicity.

PATIENTS AND PARTICIPANTS

Virus isolates from peripheral blood mononuclear cells of 13 perinatally infected children were compared for specific in vitro biologic properties.

METHODS

Virus isolates were examined for biologic properties as measured by their ability to infect H9 cells and to induce syncytia in susceptible cells.

RESULTS

Most of the pediatric HIV-1 isolates failed to infect CD4+ H9 cells and induce syncytia in susceptible cells, regardless of whether they were from children with or without AIDS. All of the isolates, however, grew well in mitogen-stimulated normal adult lymphocytes. These results are in contrast to those with HIV-1 isolates from adults, whose biologic properties were related to the stages of the disease.

CONCLUSIONS

These results indicate that, unlike adult HIV-1 isolates, the biologic properties of pediatric isolates are not related to the stages of the disease. The rapid development of disease in children may therefore be due to factors other than intrinsic properties of HIV-1 strains present in children.

[Otitis media in childhood: a critical review of the literature]

Infection of the middle ear is one of the most common childhood illnesses accounting for one-third of the pediatrics practice during the first five years of life. Therefore treatment and prevention of the otitis media are of considerable importance. A review of the literature of the otitis media during the pediatric age is reported. In fact in the last years a large amount of knowledge, sometimes referring discordant opinions, has been acquired. The Authors report epidemiology, anatomy, pathology, physiology, microbiology, classification, clinical data diagnosis and therapy of the otitis media. Common conditions of the middle ear (normal, acute otitis media, chronic otitis media, recurrent otitis media) are described. In particular acute otitis media, otitis media with effusion, perforation of the tympanic membrane, fluid level in the middle ear, severe retraction or bulging of the tympanic membrane are pointed out in color-photographs.