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Biomedical subjects

R N Allan

Publications and source records attributed to R N Allan.

At least 19 recordsLinked to original sources
PubMed2005

Brevibacillus levickii sp. nov. and Aneurinibacillus terranovensis sp. nov., two novel thermoacidophiles isolated from geothermal soils of northern Victoria Land, Antarctica.

Thirteen strains of endospore-forming bacteria were isolated from geothermal soils at Cryptogam Ridge, the north-west slope of Mt Melbourne, and at the vents and summit of Mt Rittmann in northern Victoria Land, Antarctica. 16S rRNA gene sequencing, SDS-PAGE and routine phenotypic characterization tests indicated that the seven isolates from the north-west slope of Mt Melbourne represent a novel species of Brevibacillus and that the six isolates from Cryptogam Ridge and the vents and summit of Mt Rittmann represent a novel species of Aneurinibacillus. Brevibacillus strains were not isolated from the sites at Mt Rittmann or Cryptogam Ridge and Aneurinibacillus strains were not isolated from the north-west slope of Mt Melbourne. Preliminary metabolic studies revealed that L-glutamic acid, although not essential for growth, was utilized by both species. The Brevibacillus species possessed an uptake system specific for L-glutamic acid, whereas the Aneurinibacillus species possessed a more general uptake system capable of transporting other related amino acids. Both species utilized a K(+) antiport system and similar energy systems for the uptake of l-glutamic acid. The rate of uptake by the Brevibacillus species type strain was 20-fold greater than that shown by the Aneurinibacillus species type strain. The names Brevibacillus levickii sp. nov. and Aneurinibacillus terranovensis sp. nov. are proposed for the novel taxa; the type strains are Logan B-1657(T) (= LMG 22481(T) = CIP 108307(T)) and Logan B-1599(T) (LMG 22483(T) = CIP 108308(T)), respectively.

Amino Acid Transport Systems↗
PubMed2001

How does pouch construction for a final diagnosis of Crohn's disease compare with ileoproctostomy for established Crohn's proctocolitis?

PURPOSE: There is a difference of opinion concerning the role of ileal pouch-anal anastomosis in Crohn's disease, even in the absence of small-bowel or perianal disease. One view is that ileal pouch-anal anastomosis should never be entertained, the other is that ileal pouch-anal anastomosis, like ileoproctostomy, can be justified sometimes, because it allows young people a period of stoma-free life. The aim of this study was to examine the outcome of ileal pouch-anal anastomosis and to contrast it with ileoproctostomy in patients with Crohn's disease without small-bowel or perianal disease. METHODS: Ileal pouch-anal anastomosis was performed in 23 patients with Crohn's disease (12 of whom had evidence of Crohn's disease at the time of operation and 11 who were eventually found to have Crohn's disease as a result of complications) and ileoproctostomy in 35. Patients were matched for age, gender, follow-up, and medication, but all ileoproctostomy cases had relative rectal sparing. Thus, the groups were not comparable and the reasons for ileal pouch-anal anastomosis and ileoproctostomy were therefore quite different. RESULTS: The outcome in ileal pouch-anal anastomosis at a mean follow-up of 10.2 years was pouch excision, 11 (47.8 percent); proximal stoma, 1 (4.3 percent; patient preference); average small-bowel resection, 65 cm; persistent perineal sinus, 8 of 11 having pouch excision (73 percent); and mean time in hospital, 37 (range, 8-108) days. Of those in circuit having ileal pouch-anal anastomosis (n = 12), 24-hour bowel frequency was 6, with no incontinence or urgency, but 6 (50 percent) were on medication. When ileal pouch-anal anastomosis was done for Crohn's disease in the resection specimen, only 4 of 12 (33 percent) were excised compared with 7 of 11 (64 percent) in whom the diagnosis was made as a result of complications. The outcome in ileoproctostomy at a mean follow-up of 10.9 years was rectal excision in 3 (8 percent), proximal stoma in 1 (3 percent), average small-bowel resection was 15 cm, persistent perineal sinus in 1 (3 percent), and time in hospital was 21 (range, 8-36) days. Of those in circuit (n = 32), 24-hour bowel frequency was 5, 2 had incontinence, 3 had urgency, and 12 (36 percent) were taking medication. CONCLUSIONS: These results indicate that the overall outcome of ileal pouch-anal anastomosis is inferior to that of ileoproctostomy, especially if Crohn's disease was diagnosed as a result of complications. Nevertheless, the functional results of those with a successful outcome are comparable.

Adolescent↗
PubMed2001

Long-term outcome of surgical management for diffuse jejunoileal Crohn's disease.

BACKGROUND: In diffuse jejunoileal Crohn's disease, resectional surgery may lead to short-bowel syndrome. Since 1980 strictureplasty has been used for jejunoileal strictures. This study reviews the long-term outcome of surgical treatment for diffuse jejunoileal Crohn's disease. METHODS: The cases of 46 patients who required surgery for diffuse jejunoileal Crohn's disease between 1980 and 1997 were reviewed. RESULTS: Strictureplasty was used for short strictures without perforating disease (perforation, abscess, fistula). Long strictures (<20 cm) or perforating disease was treated with resection. During an initial operation, strictureplasty was used on 63 strictures in 18 patients (39%). After a median follow-up of 15 years, there were 3 deaths: 1 from postoperative sepsis, 1 from small-bowel carcinoma, and 1 from bronchogenic carcinoma. Thirty-nine patients required 113 reoperations for jejunoileal recurrence. During 75 of the 113 reoperations (66%), strictureplasty was used on 315 strictures. Only 2 patients experienced the development of short-bowel syndrome and required home parenteral nutrition. At present, 4 patients are symptomatic and require medical treatment. All other patients are asymptomatic and require neither medical treatment nor nutritional support. CONCLUSIONS: Most patients with diffuse jejunoileal Crohn's disease can be restored to good health with minimal symptoms by surgical treatment that includes strictureplasty.

Adolescent↗
PubMed2000

Risk factors for intra-abdominal sepsis after surgery in Crohn's disease.

PURPOSE: This study examined risk factors for intra-abdominal sepsis after surgery in Crohn's disease. METHODS: We reviewed 343 patients who underwent 1,008 intestinal anastomoses during 566 operations for primary or recurrent Crohn's disease between 1980 and 1997. Possible factors for intra-abdominal sepsis were analyzed by both univariate (chi-squared test) and multivariate (multiple regression) analyses. RESULTS: Intra-abdominal septic complications, defined as anastomotic leak, intra-abdominal abscess, or enterocutaneous fistula, developed after 76 operations (13 percent). Intra-abdominal septic complications were significantly associated with preoperative low albumin level (< 30 g/l; P = 0.04), preoperative steroids use (P = 0.03), abscess at the time of laparotomy (P = 0.03), and fistula at the time of laparotomy (P = 0.04). The intra-abdominal septic complication rate was 50 percent (8/16 operations) in patients with all of these four risk factors, 29 percent (10/35 operations) in patients with three risk factors, 14 percent (14/98 operations) in patients with two risk factors, 16 percent (33/209 operations) in patients with only one risk factor, and 5 percent (11/208 operations) in patients with none of these risk factors (P<0.0001). The following factors did not affect the incidence of septic complications; age, duration of symptoms, number of previous bowel resections, site of disease, type of operation (resection, strictureplasty, or bypass), covering stoma, and number, site, or method (sutured or stapled) of anastomoses. CONCLUSIONS: Preoperative low albumin level, steroid use, and the presence of abscess or fistula at the time of laparotomy significantly increased the risk of septic complications after surgery in Crohn's disease.

Abdomen↗
PubMed2000

Audit of single-stage proctocolectomy for Crohn's disease: postoperative complications and recurrence.

PURPOSE: This study was undertaken to review our overall experience of single-stage proctocolectomy for Crohn's disease. METHODS: One hundred three patients who underwent single-stage proctocolectomy for Crohn's disease between 1958 and 1997 were reviewed. Factors affecting the incidence of recurrence were examined using a multivariate analysis. RESULTS: Principal indications for proctocolectomy were chronic colitis (49 percent), acute colitis (37 percent), and anorectal disease (14 percent). The commonest postoperative complication was delayed perineal wound healing (n = 36; 35 percent), followed by intra-abdominal sepsis (17 percent) and stomal complications (15 percent). In 23 patients the perineal wound healed between three and six months after proctocolectomy, whereas in 13 patients the wound remained unhealed for more than six months. There were two hospital deaths (2 percent) caused by sepsis. The 5-year, 10-year, and 15-year cumulative reoperation rates for small-bowel recurrence were 13, 17, and 25 percent, respectively, after a median follow-up of 18.6 years. From a multivariate analysis, factors affecting reoperation rate for recurrence were gender (male; hazard ratio 2.4 vs. female; P = 0.03) and age at operation (< or =30 years; hazard ratio 2.6 vs. >30 years; P = 0.04). The following factors did not affect the reoperation rate: duration of symptoms, smoking habits, associated perforating disease, coexisting small-bowel disease, postoperative complications, and medical treatment. CONCLUSIONS: Proctocolectomy for Crohn's disease is associated with a high incidence of complications, particularly delayed perineal wound healing. Proctocolectomy carries a low recurrence rate in the long term. However, young male patients are at high risk of recurrence.

Adolescent↗
PubMed2000

Effect of fecal diversion alone on perianal Crohn's disease.

The role of fecal diversion alone for perianal Crohn's disease remains unclear. This study was undertaken to assess its role in perianal Crohn's disease and to examine predictive factors for outcome. Thirty-one patients who underwent fecal diversion alone for perianal Crohn's disease between 1970 and 1997 were reviewed. The principal indications for fecal diversion were severe perianal sepsis in 13 patients, recurrent deep anal ulcer in 3, complex anorectal fistula in 9, and rectovaginal fistula in 6. Twenty-five patients (81%) went into early remission, and six (19%) failed to respond. Of the 25 early responders, 17 relapsed at a median duration of 23 months after fecal diversion. By contrast, 8 patients (26%) went into complete remission and required no further surgery at a median duration of 81 months after the diversion. Altogether, 22 patients required surgery at a median duration of 20 months after fecal diversion: proctectomy in 21 and repeated drainage of anal sepsis in 1. At present, intestinal continuity has been restored in only three patients (10%). The following parameters were compared in patients with and without complete remission after fecal diversion: age, gender, duration of disease, steroid use, smoking, coexisting Crohn's disease, preoperative blood indices, and Crohn's disease activity index. None of these parameters affected the outcome. In conclusion, fecal diversion alone is effective in selected patients with perianal disease, but the prospect of restoring intestinal continuity is low. There were no parameters to identify those in whom a successful outcome is likely.

Adolescent↗
PubMed1999

Perforating ileocecal Crohn's disease does not carry a high risk of recurrence but usually re-presents as perforating disease.

PURPOSE: The aim of this study was to study the natural history of perforating and nonperforating ileocecal Crohn's disease. METHODS: One hundred sixty-five cases of primary ileocecal Crohn's disease operated on between 1975 and 1995 were reviewed. Perforating disease was defined as acute free perforation, subacute perforation with an abscess, or chronic perforation with an internal or external fistula. RESULTS: Perforating disease was identified in 72 patients (44 percent); 11 with acute free perforation, 18 with abscess formation, and 43 with fistulas. Postoperative complications occurred in 29 percent of perforating and in 23 percent of nonperforating disease (not a significant difference). There was no significant difference in the cumulative reoperation-free rate for recurrence at the ileocolonic anastomosis (perforating, 78 percent vs. nonperforating, 73 percent at 5 years and perforating, 61 percent vs. nonperforating, 55 percent at 10 years), or in the median time interval from the primary to the secondary operation (perforating, 49 vs. nonperforating, 37 months). Seventy percent of perforating disease re-presented with perforating recurrence. Likewise, 83 percent of nonperforating disease re-presented with nonperforating (P < 0.0001) recurrence. Re-reoperation rate for re-recurrence at the ileocolonic anastomosis and median duration from the second operation to the third operation did not differ between perforating and nonperforating disease. Seventy-nine percent of perforating disease re-presented again with perforating disease, and 87 percent of nonperforating disease re-presented again with nonperforating disease as before (P = 0.001). CONCLUSIONS: These data suggest that perforating ileocecal disease usually re-presents in the way it did originally but does not represent a high-risk group for recurrence.

Adult↗
PubMed1999

Persistent perineal sinus after proctocolectomy for Crohn's disease.

PURPOSE: Persistent perineal sinus is a source of morbidity after proctocolectomy for Crohn's disease. This study examined the factors responsible for persistent sinus after proctocolectomy for Crohn's disease. We also assessed the outcome of surgical treatment for persistent perineal sinus. METHODS: The records of 145 patients who underwent proctocolectomy for Crohn's disease between 1970 and 1997 were reviewed. RESULTS: Persistent sinus occurred in 33 (23 percent) patients after proctocolectomy. Factors associated with a significantly greater risk of perineal sinus were younger age (P = 0.006), rectal involvement (P = 0.02), perianal sepsis (P = 0.0005), high fistulas (P = 0.04), extrasphincteric excision (P = 0.0004), and fecal contamination at operation (P = 0.0003). Multivariate analyses showed that age (P = 0.0001), rectal involvement (P = 0.007), and fecal contamination (P = 0.009) were significant independent predictive factors for perineal sinus. Fifty-six operations, including 24 radical excisions, two rectus abdominis flaps, four gracilis transpositions, and two omentoplasties were performed in 24 patients with persistent sinus, but only 9 achieved healing. Long sinuses (>10 cm) and sinuses presenting late (>12 weeks after proctocolectomy) were seldom cured by surgical treatment. CONCLUSION: Persistent perineal sinus is more likely to occur if an extrasphincteric dissection is needed because of extensive anorectal disease or if fecal contamination occurs at operation. Attempted surgical eradication of perineal sinus is often ineffective.

Adrenal Cortex Hormones↗
PubMed1999

An audit of strictureplasty for small-bowel Crohn's disease.

PURPOSE: The aim of this study was to review the long-term outcome of strictureplasty for small-bowel Crohn's disease. METHODS: We reviewed 111 patients who underwent 285 primary strictureplasties (Heineke-Mikulicz, 236; Finney, 49) between 1980 and 1997. RESULTS: Eighty-seven patients (78 percent) had had previous bowel resections. Forty-six patients (41 percent) required synchronous resection for perforating disease (abscess or fistula) or long strictures (>20 cm). The mean number of strictureplasties was three (range, 1-11). There were no operative deaths. Septic complications (fistula or intra-abdominal abscess) related to strictureplasty developed in eight patients (7 percent), of whom two required a proximal ileostomy. Abdominal symptoms were relieved in 95 percent of patients. The majority (95 percent) of patients with preoperative weight loss gained weight (median gain, +2 kg; range, -6 to +22.3 kg). After a median follow-up of 107 months, symptomatic recurrence occurred in 60 patients (54 percent). In 11 patients symptomatic recurrence was successfully managed by medical treatment. Forty-nine patients (44 percent) required reoperation for recurrence: strictureplasty alone in 22 patients, resection alone in 19 patients, strictureplasty and resection in 6 patients, and ileostomy alone in 2 patients. Eighteen patients (16 percent) required a third operation. One patient died from a small-bowel carcinoma which developed in the vicinity of a previous strictureplasty. Two of 19 patients with diffuse jejunoileal disease developed short-bowel syndrome, and were receiving longterm parenteral nutrition. Two other patients were taking corticosteroids for recurrent symptoms. All other patients were asymptomatic, receiving neither medical treatment nor nutritional support. CONCLUSIONS: Strictureplasty is a safe and efficacious procedure for small-bowel Crohn's disease in the long-term.

Adult↗
PubMed1999

Strategy for surgical management of ileocolonic anastomotic recurrence in Crohn's disease.

After resection for ileocecal or ileocolonic Crohn's disease anastomotic recurrence is common, and many patients require further surgery. This study reviews our overall experience of surgery for ileocolonic anastomotic recurrence of Crohn's disease so we can propose a strategy for management. A series of 109 patients who underwent surgery for anastomotic recurrence after ileocecal or ileocolonic resection for Crohn's disease between 1984 and 1997 were reviewed. Ileocolonic recurrence was treated by strictureplasty in 39 patients and resection in 70 (with sutured end-to-end anastomosis, 48; stapled side-to-side anastomosis, 22). Stapled anastomosis has been frequently used between 1995 and 1997. Short recurrence was mainly treated by strictureplasty, and long or perforating disease was resected. Coexisting small bowel disease was more common in the patients having strictureplasty. Septic complications (leak/fistula/abscess) related to the ileocolonic procedure occurred in 1 of 39 patients (3%) after strictureplasty, in 6 of 48 (13%) after resection with sutured anastomosis, and in none of 22 after resection with stapled anastomosis. The median duration of follow-up was 90 months after strictureplasty, 105 months after resection with sutured anastomosis, and 22 months after resection with stapled anastomosis. Altogether 18 of 39 patients (46%) after strictureplasty, 22 of 48 (46%) after resection with sutured anastomosis, and none of 22 after resection with stapled anastomosis required further surgery for suture line recurrence. In conclusion, strictureplasty is useful for short ileocolonic recurrence in patients with multifocal small bowel disease or previous extensive resection. Stapled side-to-side anastomosis was associated with a low incidence of complications, and early recurrence was not observed, although the duration of follow-up was short.

Adolescent↗
PubMed1999

Outcome of strictureplasty for duodenal Crohn's disease.

BACKGROUND: The outcome of strictureplasty for duodenal Crohn's disease has not been critically documented. The aim of this study was to assess the outcome of strictureplasty for duodenal Crohn's disease. METHODS: A retrospective review was undertaken of 13 patients who underwent strictureplasty (including four pyloroplasties) for obstructive duodenal Crohn's disease between 1974 and 1997. RESULTS: Ten patients underwent strictureplasty as the primary procedure, and in three strictureplasty was used as a revision procedure after previous bypass surgery. Two patients developed anastomotic breakdown and were treated either by Roux-en-Y duodenojejunostomy or partial gastrectomy. Symptoms of obstruction persisted in four patients after strictureplasty; three eventually resolved after prolonged nasogastric aspiration, but the other required gastrojejunostomy. In the long term, six patients developed restricture at the previous strictureplasty site. Five required repeat strictureplasty and the other patient underwent duodenojejunostomy. One patient who had repeat strictureplasty required a further strictureplasty because of restricture at the previous strictureplasty site. Overall nine of 13 patients required further surgery because of early postoperative complications or restricture at the strictureplasty site. CONCLUSION: Strictureplasty for duodenal Crohn's disease is associated with a high incidence of postoperative complications and restricture.

Adolescent↗
PubMed1999

An audit of gastroduodenal Crohn disease: clinicopathologic features and management.

BACKGROUND: This study was undertaken to assess the clinicopathologic features and management of gastroduodenal Crohn disease. METHODS: The medical records of 54 patients with gastroduodenal Crohn disease treated between 1958 and 1997 were reviewed. RESULTS: Gastroduodenal Crohn disease occurred in association with disease elsewhere in 52 patients (96%). The commonest pathology was stricture (n = 41), followed by ulceration (n = 4) and duodenocutaneous fistula (n = 2). Medical treatment was initially attempted in 31 patients, of whom 12 required no surgical treatment for gastroduodenal disease. Nineteen patients required surgery for gastroduodenal obstruction or fistula despite medical treatment. Overall, 33 patients (61%) required surgery; the indication was obstruction in 30, duodenocutaneous fistula in 2, and bleeding in 1. There was one postoperative death because of persistent bleeding and intraabdominal sepsis after oversewing of a bleeding ulcer. In obstructive disease 16 patients were treated by bypass surgery, 10 by strictureplasty, and 4 by gastrectomy. After surgery for obstructive disease anastomotic leak developed in three patients, and persistent gastric outlet obstruction was seen in six patients. In the long term 11 patients required reoperation for anastomotic obstruction (n = 9) or stomal ulceration (n = 2). For duodenocutaneous fistula one patient underwent simple closure of fistula, and the other patient duodenojejunostomy. Both of these patients developed an intra-abdominal abscess without evidence of leak. There has been no fistula recurrence. CONCLUSIONS: Gastroduodenal Crohn disease is a complex and difficult problem that is associated with serious complications and need for reoperation.

Adolescent↗
PubMed1999

Stapled functional end-to-end anastomosis versus sutured end-to-end anastomosis after ileocolonic resection in Crohn disease.

BACKGROUND: The aim of this retrospective study was to compare complications and anastomotic recurrence rates after stapled functional end-to-end versus conventional sutured end-to-end anastomosis after ileocolonic resection in Crohn disease. METHODS: Between 1988 and 1997, 123 patients underwent ileocolonic resection for Crohn disease. Forty-five patients underwent stapled functional end-to-end anastomosis (stapled group), and 78 underwent sutured end-to-end anastomosis (sutured group). RESULTS: The stapled anastomosis has been more frequently used during the past 3 years; between 1995 and 1997 it was used in 33 (83%) of 40 patients, compared with only 12 (14%) of 83 patients between 1988 and 1994. There was one anastomotic leak (2%) in the stapled group, compared with six (8%) in the sutured group. The overall complication rate was significantly lower in the stapled group (7% versus 23%, P = 0.04). In the stapled group only one patient required reoperation for ileocolonic anastomotic recurrence, compared with 26 in the sutured group. The cumulative 1-, 2- and 5-year rates for ileocolonic recurrences requiring surgery in the stapled group were 0%, 0%, and 3%, which were significantly lower than the 5%, 11%, and 24% in the sutured group (P = 0.007 by log-rank test). CONCLUSIONS: Although the follow-up duration was short in the stapled group, these results suggest that stapled functional end-to-end ileocolonic anastomosis is associated with a lower incidence of complications and that early anastomotic recurrence is less common than after sutured end-to-end anastomosis. However, a randomized trial would be necessary to draw clear conclusions.

Adolescent↗
PubMed1998

A simple clinical colitis activity index.

BACKGROUND: The appropriate medical treatment of patients with ulcerative colitis is determined largely by the severity of symptoms. Hospital assessment of the severity of disease activity includes investigation of laboratory indices and sigmoidoscopic assessment of mucosal inflammation. AIMS: To develop a simplified clinical colitis activity index to aid in the initial evaluation of exacerbations of colitis. METHODS: The information for development of the simple index was initially evaluated in 63 assessments of disease activity in patients with ulcerative colitis where disease activity was evaluated using the Powell-Tuck Index (which includes symptoms, physical signs, and sigmoidoscopic appearance). The new index was then further evaluated in 113 assessments in a different group of patients, by comparison with a complex index utilising clinical and laboratory data, as well as five haematological and biochemical markers of disease severity. RESULTS: The newly devised Simple Clinical Colitis Activity Index, consisting of scores for five clinical criteria, showed a highly significant correlation with the Powell-Tuck Index (r = 0.959, p < 0.0001) as well as the complex index (r = 0.924, p < 0.0001) and all laboratory markers (p = 0.0003 to p < 0.0001). CONCLUSIONS: This new Simple Colitis Activity Index shows good correlation with existing more complex scoring systems and therefore could be useful in the initial assessment of patients with ulcerative colitis.

Acute Disease↗