Michael W. Mulholland

Restaging of locally advanced rectal cancer with magnetic resonance imaging and endoluminal ultrasound after preoperative chemoradiotherapy: a systemic review and meta-analysis.

BACKGROUND: Magnetic resonance imaging and endoluminal ultrasound play an important role in the restaging of locally advanced rectal cancer after preoperative chemoradiotherapy, yet their diagnostic accuracy is still controversial. OBJECTIVE: Meta-analysis was performed to estimate the diagnostic performance of MRI and endoluminal ultrasound. DATA SOURCES: Electronic databases from 1996 to March 2012 were searched. STUDY SELECTION AND INTERVENTIONS: Either MRI or endoluminal ultrasound was used to restage rectal cancer after chemoradiotherapy or radiation. MAIN OUTCOME MEASURES: T category, lymph node, and circumferential resection involvement were measured. RESULTS: The sensitivity estimate for rectal cancer diagnosis (T0) by endoluminal ultrasound (37.0%; 95% CI, 24.0%–52.1%) was higher (p = 0.04) than the sensitivity estimate for MRI (15.3%; 95% CI, 6.5%–32.0%). For T3-4 category, sensitivity estimates of MRI and endoluminal ultrasound were comparable, 82.1% and 87.6%, whereas specificity estimates were poor (53.5% and 66.4%). For lymph node involvement, there was no significant difference between the sensitivity estimates for MRI (61.8%) and endoluminal ultrasound (49.8%). Specificity estimates for MRI and endoluminal ultrasound were 72.0% and 78.7%. For circumferential resection margin involvement, MRI sensitivity and specificity were 85.4% and 80.0%. LIMITATIONS: To identify the heterogeneity, metaregression was performed on covariates. However, few of the covariates were identified to be statistically significant because of the lack of adequate original data. CONCLUSION: Accurate restaging of locally advanced rectal cancer by MRI and endoluminal ultrasound is still a challenge. Identifying T0 rectal cancer by imaging is not reliable. Before performing surgery, restaging is important, but some of the T0-2 patients are likely overestimated as T3-4. Both modalities for lymph node involvement are not very good. Magnetic resonance imaging may be a good method to reassess circumferential resection margin.

The Role of Luminal Contents in Radiation Enteritis

A guinea pig model was used to evaluate luminal content as a factor in the development of acute radiation enteritis. Surgical bypass of one half of the small bowel created an isolated segment free of luminal contents. Radiation effects on this empty intestine were compared with effects on bowel in continuity, on intestine containing bile only, and on intestine containing pancreatic enzymes plus food. The animals were subjected to a single dose of 1600 rad via an abdominal port and killed 4 days later. Surviving crypts per circumference provided one index of the severity of the injury. Intestinal damage was further evaluated by histologic grading. Surviving crypts were significantly fewer for irradiated segments of bowel containing any of the components of the intestinal stream compared to either nonirradiated controls or irradiated but empty bowel. Histologic scoring revealed a gradation of injury, with progressively more severe damage in empty irradiated bowel, and in intestine containing only pancreatic secretion, bile, and all components of the luminal stream. We conclude that both bile and pancreatic secretions in the lumen enhance acute radiation‐induced small‐bowel injury.

Gastrointestinal complications of congenital immunodeficiency states. The surgeon's role.

Ninety-one congenitally immunodeficient patients treated from 1972 to 1981 were reviewed to assess the incidence and nature of gastrointestinal complications. Thirty-three of these patients (36%) developed 59 complications. Patients with immunodeficiencies characterized by neutrophil dysfunction--chronic granulomatous disease (20 patients) and cyclic neutropenia (eight patients)--developed 22 surgical infections, 22 of which required operation. In patients with neutrophil defects, postoperative morbidity was frequent and severe. Gastrointestinal symptoms were common in patients with isolated defects of B or T lymphocytes. Ten of forty-one patients with congenital hypogammaglobulinemia developed gastrointestinal complications, as did one of four patients with DiGeorge Syndrome, and the single patient with secretory IgA deficiency. However, operation was not required for these patients with isolated disorders of lymphocyte function. Patients with combined B and T cell disorders developed gastrointestinal disease, requiring operative therapy at intermediate rates. Gastrointestinal symptoms developed in four of nine patients with severe combined immunodeficiency and three of eight with Wiskott-Aldrich syndrome. Operative therapy was required in two of these seven symptomatic patients.

In-continuity gastrointestinal stapling

Several surgical procedures have been proposed to interrupt continuity of the gut, without transection, by means of a row of staples. Using the dog, we investigated the functional and histologic results of incontinuity stapling of the gastric antrum, the small intestine, and the colon. After creation of an end antrostomy, ileostomy, or colostomy, a staple line was placed proximal to the stoma (TA 55-4.8 mm staples). Decompression of the bowel proximal to the staple line was accomplished by an enteric anastomosis. Separation of the staple closure was detected by intestinal contents exiting from the stoma. Animals were sacrificed at the time of disruption, and specimens were obtained for histologic examination.Three of five antral closures broke down at a mean of 19.6 days after operation. All five small-bowel staple lines opened at a mean of 12.4 days. Five of five colonic staple lines disrupted 13.0 days postoperatively. The staples pulled through the bowel wall without losing their “B” shaped configuration. Microscopic examination showed intact mucosa across the staple line, with no submucosa to submucosa healing.Staple lines in the undivided small bowel or colon disrupt after approximately two weeks, due to lack of fibrotic healing. Staple interruptions of the gastric antrum also disrupt, but with less regularity.

Splanchnic and cerebral vasodilatory effects of calcitonin gene-related peptide I in humans

The ability of synthetic human calcitonin gene-related peptide (CGRP I) to act as an arterial vasodilator was tested in healthy men by measuring arterial blood flow parameters in carotid, superior mesenteric, celiac, and femoral vessels. Calculated volume flow was significantly increased (140 +/- 21% of basal) in the SMA with a 2-ng/kg/min infusion of CGRP. Carotid artery volume flow increased dose dependently (96 +/- 6%, 122 +/- 15%, 135 +/- 15% of basal, respectively, with 2, 4, or 8 ng/kg/min). With steady-state infusion, carotid and superior mesenteric arterial flow parameters remained significantly elevated for 30 minutes after cessation of peptide administration. Blood pressure was unchanged. Pulse increased dose dependently. Arterial diameters were unchanged, implying activity at the arteriolar level.

Antral proliferation of G cells after truncal, parietal cell, and antral vagotomy

Abstract Antral gastrin cell numbers and serum gastrin levels were studied in five groups of rats: (1) control, (2) truncal vagotomy, (3) truncal vagotomy with pyloroplasty, (4) parietal cell vagotomy, and (5) antral vagotomy. Female Sprague-Dawley rats weighing approximately 225 g were used. Eighteen days after operation radiographic study was performed to assess gastric size and emptying rate. At sacrifice serum was obtained for gastrin assay, gastric pH measured, and the antrum removed for G-cell quantitation. Gastric pH was elevated in all groups except antral vagotomy. Variable degrees of gastric distention and delayed gastric emptying were observed in the rats with truncal vagotomy alone, truncal vagotomy plus pyloroplasty, and antral vagotomy. Parietal cell vagotomy rats had no change in gastric size or emptying rate. Rats with truncal vagotomy, truncal vagotomy plus pyloroplasty, and parietal cell vagotomy had significant increases in serum gastrin levels and in G-cell density. Antral vagotomy resulted in no significant differences from controls. A gastrin inhibitory mechanism residing in the corpus may become inoperative after vagal denervation. Alternatively, proliferation of G cells and increased serum gastrin levels may be a consequence of decreased luminal acid after vagotomy. Vagal innervation of the corpus is a critical variable in control of the antral G-cell mass, but antral innervation is not. Distention by itself does not seem to produce G-cell hyperplasia.

Surgery of the Immunodeficient Child

A great deal has been learned about the surgery of immunodeficient patients. If one assesses the problem and follows the surgical principles described, in most instances one can solve the problem and be a great help to the oncologist and immunotherapist. A team approach is most important.