A review of the management of small bowel obstruction. Members of the Surgical and Clinical Adhesions Research Study (SCAR)

Small bowel obstruction is a significant surgical problem and is commonly caused by postoperative adhesions. Patients suffering from this condition are often difficult to assess and require careful evaluation and management. Articles regarding the diagnosis, evaluation and management of small bowel obstruction have been identified from the Ovid, Embase and Silver Platter electronic databases and then reviewed by the authors. Particular emphasis has been placed on randomised controlled trials or large prospective series. Anecdotal reports or those containing small numbers have been largely excluded, but where they have been included it has been made clear in the text. The management of small bowel obstruction is predominantly the management of obstruction due to postoperative adhesions. The selective use of radiological techniques, such as water soluble contrast and CT studies, often help to characterise the nature of the obstruction and may even help with its resolution. Techniques involving the use of laparoscopy and barrier membranes may reduce morbidity but there is a need to evaluate these strategies further with prospective clinical trials.

Hyperventilation following a large-scale hazardous-materials incident

Actual or perceived exposure to hazardous materials may result in physiologic and psychological effects. However, hyperventilation following such exposures has not previously been reported. After a large-scale industrial release of oxides of nitrogen, five (29%) of 17 patients evaluated at a major trauma center were hyperventilating, as defined by arterial PCO2 <33 mm Hg, and nine patients (53%) had arterial PCO2 <37 mm Hg. First responders (rescue team members and paramedics) had a higher rate of hyperventilation than other occupational groups. Age, gender, marital status, decontamination, and mode of arrival were not significantly associated with hyperventilation, although marital status approached significance. This study suggests that hyperventilation may be a common reaction after hazardous-materials incidents, and that certain populations may be at increased risk for this condition.

The evolution of species interactions

Interactions between species are as evolutionarily malleable as the species themselves and have played a central role in the diversification and organization of life. This malleability creates complex geographic mosaics in interspecific interactions that can evolve rapidly over decades, blurring the distinction between evolutionary time and ecological time and making the study of coevolution crucial for human health and welfare.

The role of fibrinolytic system proteins in cholesterol gallstone formation

BACKGROUND

Accelerated nucleation, supersaturation of bile, and biliary stasis are known to be key factors in cholesterol gallstone formation. The mechanisms through which these factors interact to form stones are still incompletely understood. Among the proteins now known to be present in bile are several components of the fibrinolytic system: tissue plasminogen activator, urokinase-like plasminogen activator, and plasminogen activator inhibitors 1 and 2. The concentrations of plasminogen activator inhibitors 1 and 2 in gallbladder bile are increased in patients with gallstones. The aim of this study was to determine whether these fibrinolytic system proteins act as pro-nucleating agents for cholesterol gallstone formation.

METHODS

Nucleation assays were done on gallbladder bile from eight cholesterol stone patients and eight control patients. The effects of tissue plasminogen activator, urokinase-like plasminogen activator, and plasminogen activator inhibitors I and 2 on cholesterol crystal appearance time (CCAT) were tested, by direct observation using polarizing microscopy, after measurement of biliary lipids and calculation of cholesterol saturation indices.

RESULTS

There was no significant difference in cholesterol saturation indices between bile that nucleated and bile that did not (mean, 2.0 +/- 1.5 versus 1.8 +/- 0.5). When all samples in which nucleation occurred were compared, tissue plasminogen activator significantly shortened CCAT median from 4.75 days (range, 2-21) to 3.5 days (2.5-18) (P < 0.05). This was similar to the effect of fibronectin (3.75 days; range, 2-20), a known pro-nucleator used as a nucleation accelerating control (P < 0.05). None of the other fibrinolytic system proteins significantly accelerated CCAT.

CONCLUSIONS

The results of this study suggest that tissue plasminogen activator may act as a pro-nucleating agent for cholesterol gallstone formation in gallbladder bile.

Adhesion-related hospital readmissions after abdominal and pelvic surgery: a retrospective cohort study

BACKGROUND

Adhesions after abdominal and pelvic surgery are important complications, although their basic epidemiology is unclear. We investigated the frequency of such complications in the general population to provide a basis for the targeting and assessment of new adhesion-prevention measures.

METHODS

We used validated data from the Scottish National Health Service medical record linkage database to identify patients undergoing open abdominal or pelvic surgery in 1986, who had no record of such surgery in the preceding 5 years. Patients were followed up for 10 years and subsequent readmissions were reviewed and outcomes classified by the degree of adhesion. We also assessed the rate of adhesion-related admissions in 1994 for the population of 5 million people.

FINDINGS

1209 (5.7%) of all readmissions (21,347) were classified as being directly related to adhesions, with 1169 (3.8%) managed operatively. Overall, 34.6% of the 29,790 patients who underwent open abdominal or pelvic surgery in 1986 were readmitted a mean of 2.1 times over 10 years for a disorder directly or possibly related to adhesions, or for abdominal or pelvic surgery that could be potentially complicated by adhesions. 22.1% of all outcome readmissions occurred in the first year after initial surgery, but readmissions continued steadily throughout the 10-year period. In 1994, 4199 admissions were directly related to adhesions.

INTERPRETATION

Postoperative adhesions have important consequences to patients, surgeons, and the health system. Surgical procedures with a high risk of adhesion-related complications need to be identified and adhesion prevention carefully assessed.

Molecular basis of iduronate-2-sulphatase gene mutations in patients with mucopolysaccharidosis type II (Hunter syndrome)

Mucopolysaccharidosis type II (Hunter syndrome) is an X linked lysosomal storage disorder resulting from heterogeneous mutations in the iduronate-2-sulphatase (IDS) gene. To detect IDS gene mutations, direct sequencing of IDS cDNA fragments coupled with assays on IDS genomic amplicons was applied to 18 unrelated patients with MPS II. Seventeen mutations were detected from the 18 patients including seven missense mutations (S71R, A82E, A85T, R88C, R468W, R468Q, and E521V), five deletions (alphaR95, 383delAT, 596delAACA, 1148delC, and 1216delCT), two insertions (208insC and 1063insA), two splicing mutations (1006+5g-->c in intron 7, 1122C-->T in exon 8), and an intragenic deletion of IDS exons 4, 5, 6, and 7. Nine of the small mutations were novel mutations. Mutation 596del-AACA was detected in two unrelated patients. The mutation in intron 7 was found to cause aberrant splicing and resulted in a 22 bp insertion into its mRNA transcript. The intragenic deleted IDS gene expressed two aberrant mRNA transcripts consisting of exons 1-2-8-9 and 3-8-9. Analysis of mutations A85T, R88C, R468Q, R468W, and 438C/T found no polymorphism for the four missense mutations but about 36% heterozygosity for the 438C/T silent mutation. These results provide further evidence of mutational heterogeneity for MPS II. Also, underlying sequence directed mutagenesis mechanisms for some recurrent mutations in the IDS gene were proposed.

Analysis of common mutations and associated haplotypes in Chinese patients with glucose-6-phosphate dehydrogenase deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a rare disease in North China. In the present investigation, DNA samples from 17 patients with G6PD deficiency from Tianjin area in North China were studied for the two G6PD common mutations (R459L and R463H) and two single nucleotide polymorphisms (1311C/T and 1365-13T/C) using a dideoxy fingerprinting method. Five patients were positive for mutation R459L, and six patients were positive for mutation R463H. Further haplotype analyses using three flanking dinucleotide repeat polymorphism loci, DXS1123, DXS1113, and F8C(IVS13), were performed on 14 patient families and 16 control Chinese females. The results indicated that the two common mutations were from different haplotypes. Also, the data suggested a possible allelic association between the two G6PD common mutations and the F8C(IVS13) locus and a different allelic distribution for loci DXS1113 and F8C(IVS13) between Chinese and Caucasian populations.

Volumetric neuroimaging in Usher syndrome: evidence of global involvement

Usher syndrome is a group of genetic disorders consisting of congenital sensorineural hearing loss and retinitis pigmentosa of variable onset and severity depending on the genetic type. It was suggested that the psychosis of Usher syndrome might be secondary to a metabolic degeneration involving the brain more diffusely. There have been reports of focal and diffuse atrophic changes in the supratentorial brain as well as atrophy of some of the structures of the posterior fossa. We previously performed quantitative analysis of magnetic resonance imaging studies of 19 Usher syndrome patients (12 with type I and 7 with type II) looking at the cerebellum and various cerebellar components. We found atrophy of the cerebellum in both types and sparing of cerebellar vermis lobules I-V in type II Usher syndrome patients only. We now have studied another group of 19 patients (with some overlap in the patients studied from the previous report) with Usher syndrome (8 with type I, 11 with type II). We performed quantitative volumetric measurements of various brain structures compared to age- and sex-matched controls. We found a significant decrease in intracranial volume and in size of the brain and cerebellum with a trend toward an increase in the size of the subarachnoid spaces. These data suggest that the disease process in Usher syndrome involves the entire brain and is not limited to the posterior fossa or auditory and visual systems.

Sulfamidase deficiency in a family of Dachshunds: a canine model of mucopolysaccharidosis IIIA (Sanfilippo A)

Mucopolysaccharidosis IIIA (MPS IIIA or Sanfilippo A, McKusick 25290) was diagnosed in two adult wire-haired Dachshund littermates. Clinical and pathologic features paralleled the human disorder; both dogs exhibited progressive neurologic disease without apparent somatic involvement. Pelvic limb ataxia was observed when the dogs were 3 y old and progressed gradually within 1-2 y to severe generalized spinocerebellar ataxia. Mentation remained normal throughout the course of the disease. A mucopolysaccharide storage disorder was indicated in both dogs by positive toluidine blue spot tests of urine. The diagnosis of MPS IIIA was confirmed by documentation of urinary excretion and tissue accumulation of heparan sulfate and decreased sulfamidase activity in fibroblasts and hepatic tissue. Mild cerebral cortical atrophy and dilation of the lateral ventricles were grossly evident in both dogs. Light microscopically, fibroblasts, hepatocytes, and renal tubular epithelial cells were vacuolated. Within the nervous system, cerebellar Purkinje cells, neurons of brainstem nuclei, ventral and dorsal horns, and dorsal ganglia were distended with brightly autofluorescent, periodic acid-Schiff-positive, sudanophilic material. Ultrastructurally, visceral storage presented as membrane-bound vacuoles with finely granular, variably electron-lucent contents. Neuronal storage appeared as membranous concentric whorls, lamellated parallel membrane stacks, or electron-dense lipid-like globules. This represents the first reported animal disease homolog of the human Sanfilippo A syndrome.

Mutation rate: a simple concept has become complex

The factors that cause new mutations or affect the rate at which they occur have important implications for many areas of genetics. But recent work on phenomena such as premeiotic mutations, which yield a cluster of identical new mutants at the some time, led us to realize that researchers are using the term "mutation rate" in different, and sometimes contradictory, ways. One premeiotic genetic change may ultimately yield several new mutant offspring, but should this be considered one new mutation or many? The way the data are handled in analyses can have a significant effect on the results. How, then, does one handle clusters in the estimation of mutation rates? We explore this question and propose that geneticists begin to distinguish clearly between three different phenomena that to this point have been given the same name: the initial prerepair "genetic damage rate," the postrepair "mutational event rate," and the observed "mutation rate" as it is expressed in the proportion of new mutant offspring. We believe that all new mutant offspring should be counted when estimating mutation rate, irrespective of when in the developmental cycle it is believed that the initial mutational event occurred.

Comparison of SSCP analysis and CFLP analysis for mutation detection in the human iduronate 2-sulfatase gene

Scanning methodologies are used for the identification of DNA fragments that differ from the normal nucleotide sequence. Fragments that produce abnormal band patterns are sequenced for characterization of the exact mutation. Factors considered in choosing a scanning methodology include reproducibility, sensitivity, and time. In the present study, we compared single-stranded conformational polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) methodologies for mutation scanning of exon VIII in the iduronate 2-sulfatase (IDS) gene. Mutations of the IDS gene result in an X-linked lysosomal storage disease, Hunter syndrome. These six known mutations analyzed by the two methods included a one base pair deletion, a one base pair insertion, and four point mutations. SSCP analysis detected all of the mutations and CFLP analysis detected three of the six mutations. We concluded that SSCP analysis was preferable to CFLP analysis for scanning exon VIII in the IDS gene for mutations.

Moral imperatives for academic medicine

As the health care system becomes dominated by managed care, academic medicine must do more than simply learn how to continue to offer the same level of care with ever-tightening resources and in new practice environments. Three moral imperatives must guide how medicine is practiced and taught: (1) patients' health and well-being must always be foremost, centered in quality of care and respect for life; (2) the emotional and spiritual needs of patients must be considered, not just the physical needs; (3) academic medicine must instill in its trainees discipline, passion, and skills to meet their obligation to be lifelong learners. These imperatives make it more important than ever for medical educators to tackle two crucial questions: What kind of person makes the best possible physician? And what constitutes the best possible training for that person? Taking these questions seriously in the new era of health care may mean that medical educators need to rethink the teaching of medicine. One example of how this might be done is the Curriculum for 2002 Committee recently formed at the Wake Forest University School of Medicine. It is becoming clear that medical educators can do a better and more comprehensive job of helping future physicians uncover and strengthen their own morality and, in the face of managed care's pressures, renew their loyalty to medicine as a service rather than a business. Morally sensitized physicians can better deal with the hard issues of medicine, such as euthanasia and abortion, and can help their students examine these issues. Most important, they can show their students that physicians are members of a moral community dedicated to something other than its own self-interest.

Macrocerebellum: neuroimaging and clinical features of a newly recognized condition

Other than hamartomatous enlargement of the cerebellum as in Lhermitte-Duclos syndrome, diffuse enlargement of the cerebellum is not clearly described. We report four patients (ages 9 months to 2 years) with diffusely enlarged cerebelli as identified by measurement of the cerebellum and comparison to age appropriate normal values. The cerebellar measurements were determined in absolute numbers and expressed as ratios of cerebellum to whole brain and supratentorial brain. The clinical features of these four children (3 boys, 1 girl) consistently include global developmental delay, tone abnormalities, preserved reflexes, delayed or abnormal maturation of the visual system (oculomotor apraxia), and deficient or delayed myelination of cerebral white matter. The etiology of the macrocerebellum is unknown but we propose that the cerebellum is responding to the elaboration of growth factors intended to augment the slow development of cerebral structures. Regardless of the etiology, the finding of a macrocerebellum appears to allow the clinician to predict the clinical features of the patient and probably represents a marker for disturbed cerebral development.