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Biomedical subjects

Neil Hyman

Publications and source records attributed to Neil Hyman.

At least 19 recordsLinked to original sources
PubMed2007

Serotonin and its role in colonic function and in gastrointestinal disorders.

Serotonin (5-HT) is most commonly thought of as a neurotransmitter in the central nervous system. However, the predominant site of serotonin synthesis, storage, and release is the enterochromaffin cells of the intestinal mucosa. Within the intestinal mucosa, serotonin released from EC cells activates neural reflexes associated with intestinal secretion, motility, and sensation. Two important receptors for serotonin that are located in the neural circuitry of the intestines are the 5-HT(3) and 5-HT(4) receptors; these are the targets of drugs designed to treat gastrointestinal disorders. 5-HT(3) receptor antagonists are used to treat nausea and emesis associated with chemotherapy and for functional disorders associated with diarrhea. 5-HT(4) receptor agonists are used as promotility agents to promote gastric emptying and to alleviate constipation. Because of the importance of serotonin in normal gut function and sensation, a number of studies have investigated potential changes in mucosal serotonin signaling in pathologic conditions. Despite the inconsistencies in the current literature, changes in serotonin signaling have now been demonstrated in inflammatory bowel disease, irritable bowel syndrome, postinfectious irritable bowel syndrome, and idiopathic constipation. Emerging evidence has led to many contradictory theories regarding serotonin signaling and its roles in the pathology of gut disorders. This review summarizes the current medications affecting serotonin signaling and provides an overview of our current knowledge of the changes in serotonin that occur in pathologic conditions.

Animals↗
PubMed2006

Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society.

Adenomatous polyps are the most common neoplastic findings discovered in people who undergo colorectal screening or who have a diagnostic work-up for symptoms. It was common practice in the 1970s for these patients to have annual follow-up surveillance examinations to detect additional new adenomas and missed synchronous adenomas. As a result of the National Polyp Study report in 1993, which showed clearly in a randomized design that the first postpolypectomy examination could be deferred for 3 years, guidelines published by a gastrointestinal consortium in 1997 recommended that the first follow-up surveillance take place 3 years after polypectomy for most patients. In 2003 these guidelines were updated and colonoscopy was recommended as the only follow-up examination, stratification at baseline into low risk and higher risk for subsequent adenomas was suggested. The 1997 and 2003 guidelines dealt with both screening and surveillance. However, it has become increasingly clear that postpolypectomy surveillance is now a large part of endoscopic practice, draining resources from screening and diagnosis. In addition, surveys have shown that a large proportion of endoscopists are conducting surveillance examinations at shorter intervals than recommended in the guidelines. In the present report, a careful analytic approach was designed to address all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be stratified more definitely at their baseline colonoscopy into those at lower risk or increased risk for a subsequent advanced neoplasia. People at increased risk have either 3 or more adenomas, high-grade dysplasia, villous features, or an adenoma 1 cm or larger in size. It is recommended that they have a 3-year follow-up colonoscopy. People at lower risk who have 1 or 2 small (<1 cm) tubular adenomas with no high-grade dysplasia can have a follow-up evaluation in 5-10 years, whereas people with hyperplastic polyps only should have a 10-year follow-up evaluation, as for average-risk people. There have been recent studies that have reported a significant number of missed cancers by colonoscopy. However, high-quality baseline colonoscopy with excellent patient preparation and adequate withdrawal time should minimize this and reduce clinicians concerns. These guidelines were developed jointly by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society to provide a broader consensus and thereby increase the use of the recommendations by endoscopists. The adoption of these guidelines nationally can have a dramatic impact on shifting available resources from intensive surveillance to screening. It has been shown that the first screening colonoscopy and polypectomy produces the greatest effects on reducing the incidence of colorectal cancer in patients with adenomatous polyps.

Adenomatous Polyposis Coli↗
PubMed2006

Guidelines for colonoscopy surveillance after cancer resection: a consensus update by the American Cancer Society and the US Multi-Society Task Force on Colorectal Cancer.

Patients with resected colorectal cancer are at risk for recurrent cancer and metachronous neoplasms in the colon. This joint update of guidelines by the American Cancer Society and the US Multi-Society Task Force on Colorectal Cancer addresses only the use of endoscopy in the surveillance of these patients. Patients with endoscopically resected Stage I colorectal cancer, surgically resected Stages II and III cancers, and Stage IV cancer resected for cure (isolated hepatic or pulmonary metastasis) are candidates for endoscopic surveillance. The colorectum should be carefully cleared of synchronous neoplasia in the perioperative period. In nonobstructed colons, colonoscopy should be performed preoperatively. In obstructed colons, double-contrast barium enema or computed tomography colonography should be performed preoperatively, and colonoscopy should be performed 3 to 6 months after surgery. These steps complete the process of clearing synchronous disease. After clearing for synchronous disease, another colonoscopy should be performed in 1 year to look for metachronous lesions. This recommendation is based on reports of a high incidence of apparently metachronous second cancers in the first 2 years after resection. If the examination at 1 year is normal, then the interval before the next subsequent examination should be 3 years. If that examination is normal, then the interval before the next subsequent examination should be 5 years. Shorter intervals may be indicated by associated adenoma findings (see "Guidelines for Colonoscopy Surveillance After Polypectomy: A Consensus Update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society"). Shorter intervals also are indicated if the patient's age, family history, or tumor testing indicate definite or probable hereditary nonpolyposis colorectal cancer. Patients undergoing low anterior resection of rectal cancer generally have higher rates of local cancer recurrence compared with those with colon cancer. Although effectiveness is not proven, performance of endoscopic ultrasound or flexible sigmoidoscopy at 3- to 6-month intervals for the first 2 years after resection can be considered for the purpose of detecting a surgically curable recurrence of the original rectal cancer.

Colectomy↗
PubMed2005

Localizing colorectal cancer by colonoscopy.

HYPOTHESIS: Colonoscopic localization of colorectal carcinoma is frequently inaccurate and unreliable. DESIGN: Consecutive case series. SETTING: Tertiary care teaching hospital. PATIENTS: Three hundred fourteen consecutive patients undergoing surgical resection for colorectal cancer from January 1, 2000, to December 31, 2003. INTERVENTION: Surgical resection for colorectal cancer. MAIN OUTCOME MEASURE: Incidence of erroneous site localization. RESULTS: Two hundred thirty-six patients had complete endoscopic, pathologic, and operative records. Colonoscopy was inaccurate for tumor localization in 49 cases (21%). In 27 (11%) of these cases, a different procedure was required than initially planned; in an additional 10 cases (4%), the surgical approach required modification. Inaccurate localization was associated with previous colorectal procedures on both univariate analysis (odds ratio, 3.94; 95% confidence interval, 1.50-10.32; P<.005) and multivariate analysis (odds ratio, 4.47; 95% confidence interval, 1.64-12.08; P = .003). Having the colonoscopy performed by a surgeon trended toward protection from error on multivariate analysis (odds ratio, 0.47; 95% confidence interval, 0.20-1.08; P = .07). Age, sex, diverticular disease, endoscopist volume and years of training, and bowel preparation had no significant effect. CONCLUSIONS: Colonoscopy has a considerable error rate for localization of colorectal cancer, especially when previous colorectal procedures have been performed. Adjunctive localizing techniques, such as endoscopic tattooing, should be strongly considered.

Adult↗
PubMed2005

Practice parameters for the management of rectal cancer (revised).

The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Standards Committee is composed of Society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Adenocarcinoma↗
PubMed2005

Practice parameters for the treatment of perianal abscess and fistula-in-ano (revised).

The American Society of Colon and Rectal Surgeons is dedicated to assuring high-quality patient care by advancing the science, prevention, and management of disorders and diseases of the colon, rectum, and anus. The Standards Committee is composed of Society members who are chosen because they have demonstrated expertise in the specialty of colon and rectal surgery. This Committee was created to lead international efforts in defining quality care for conditions related to the colon, rectum, and anus. This is accompanied by developing Clinical Practice Guidelines based on the best available evidence. These guidelines are inclusive, and not prescriptive. Their purpose is to provide information on which decisions can be made, rather than dictate a specific form of treatment. These guidelines are intended for the use of all practitioners, health care workers, and patients who desire information about the management of the conditions addressed by the topics covered in these guidelines. It should be recognized that these guidelines should not be deemed inclusive of all proper methods of care or exclusive of methods of care reasonably directed to obtaining the same results. The ultimate judgment regarding the propriety of any specific procedure must be made by the physician in light of all of the circumstances presented by the individual patient.

Abscess↗
PubMed2005

Venous thromboembolism prophylaxis in colorectal surgery.

Patients who undergo colorectal surgery are at a substantially higher risk for deep vein thrombosis (DVT) than their general surgery counterparts. The incidence of DVT in colorectal surgery patients who do not receive prophylaxis is approximately 30%; a four-fold increase exists in the incidence of pulmonary embolism. The precise reasons for the increased risk are uncertain; likely, contributing factors are the need for pelvic dissection, patient positioning (eg, use of stirrups), and indications for surgery (eg, inflammatory bowel disease, cancer). Despite the clear evidence that supports the safety and efficacy of DVT prophylaxis, appropriate preventive measures are frequently not used. Heparin preparations and mechanical compression in combination likely represents the most appropriate prophylactic regimen in these high-risk patients. Standard heparin appears to be as effective as low-molecular-weight heparin and considerably less costly. In the presence of relatively poor adherence to consensus guidelines for prophylaxis, critical pathways or electronic alerts may be useful to facilitate compliance with appropriate preventive measures.

Anticoagulants↗
PubMed2004

Diverticulitis in young patients: is resection after a single attack always warranted?

PURPOSE: Diverticulitis has been described as a more virulent disease in young patients, necessitating an aggressive surgical approach. We hypothesized that the subgroup of young patients who do not require surgery on their initial presentation are unlikely to present at a later date with perforation and do not always require prophylactic resection as commonly recommended. METHODS: A retrospective chart review was conducted of all patients presenting to Fletcher Allen Health Care, the teaching hospital of the University of Vermont, from January 1, 1990 to June 30, 2001. Outcomes in patients aged 50 years or younger (Group 1) were compared with patients older than aged 50 years (Group 2) using a log-rank test. RESULTS: A total of 762 patients were admitted with sigmoid diverticulitis during the study period, 238 (31 percent) of whom underwent surgery. Two hundred fifty-nine patients (34 percent) were younger than aged 50 years (Group 1). The risk of requiring surgery on initial hospital presentation was similar between the two groups (24 vs. 22 percent, respectively; P = 0.8). However, Group 1 patients were more likely to be treated operatively at some point during the study period (40 vs. 26 percent; P = 0.001) because of an increase in elective resections. Of 196 patients in Group 1 who had an initial medically managed admission, only 1 presented at a later date with perforation (0.5 percent). CONCLUSIONS: The risk of subsequent diverticular perforation in medically managed young patients with sigmoid diverticulitis is very low. As such, the frequently espoused policy of routine surgery after a single attack of diverticulitis in young patients may not be warranted. A more selective approach seems to be safe.

Adult↗
PubMed2004

Incontinence after lateral internal sphincterotomy: a prospective study and quality of life assessment.

PURPOSE: Lateral internal sphincterotomy is an effective treatment for chronic anal fissures; however, the risk of "incontinence" has generated interest in pharmacologic approaches that are far less effective and may be poorly tolerated. This study was designed to objectively define the risk of incontinence with sphincterotomy using the Fecal Incontinence Severity Index and assess the implications for quality of life using the Fecal Incontinence Quality of Life Scale. METHODS: A prospective study was undertaken on all patients undergoing lateral internal sphincterotomy for a chronic anal fissure by a single surgeon at a university teaching hospital from January 1, 2000 to September 30, 2002. All patients had failed at least six weeks of nonoperative management. Patient demographics and use of nitroglycerin were noted. The Fecal Incontinence Severity Index was measured preoperatively and at a six-week postoperative visit when fissure healing and postoperative complications were assessed. The Fecal Incontinence Quality of Life Scale was administered to patients with an incontinence score>0. RESULTS: Thirty-five patients (15 males) underwent sphincterotomy during the study period. Thirty-one of 35 had failed nitrates: 10 because of unacceptable side effects, and 21 because of lack of efficacy. Thirty-two patients returned for their six-week postoperative visits, and two completed their questionnaires by telephone. One patient was lost to follow-up. Mean age was 41.2 (range, 21-67) years. Thirty of 32 (94 percent) evaluable fissures had healed by six weeks, one healed by three months, and the other required V-Y anoplasty. There were two minor complications. Three patients had postoperative deterioration in their continence score. Quality of life deteriorated in only one patient. CONCLUSIONS: Lateral internal sphincterotomy is a safe and effective treatment for chronic anal fissures that only occasionally impairs continence and rarely diminishes quality of life.

Adult↗