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Biomedical subjects

A A Lewis

Publications and source records attributed to A A Lewis.

At least 19 recordsLinked to original sources
PubMed2000

Radioimmunoguided surgery in colorectal cancer using a genetically engineered anti-CEA single-chain Fv antibody.

In radioimmunoguided surgery (RIGS), a radiolabeled antibody is given i.v. before surgery and a hand-held gamma-detecting probe is used to locate tumor in the operative field. The rapid blood clearance and good tumor penetration of single-chain Fv antibodies (scFv) offer potential advantages over larger antibody molecules used previously for RIGS. A Phase I clinical trial is reported on RIGS with scFv (MFE-23-his) to carcinoembryonic antigen (CEA). Thirty-four patients undergoing surgery for colorectal carcinoma (17 primary tumors, 16 liver metastases, and 1 anastomotic recurrence) and 1 patient with liver metastases of pancreatic carcinoma received 125I-labeled MFE-23-his scFv (125I-MFE-23-his) 24, 48, 72, or 96 h before operation. 125I-MFE-23-his showed biexponential blood clearance with alpha and beta half-lives of 0.32 and 10.95 h, respectively. The abdomen was scanned during surgery with a hand-held gamma detecting probe (Neoprobe Corp.). 125I-MFE-23-his showed good tumor localization; comparison with histology showed overall accuracy of 84%. Highest median ratios for tumor:normal tissue and tumor:blood were recorded 72 or 96 h after scFv injection for patients undergoing resection of liver metastases. High levels of radioactivity were found in the kidneys. Five patients had grade 1 fever, and three had a grade 1 rise in blood pressure according to the Common Toxicity Criteria. There was a significant correlation between these ratios and those measured in excised tissues using a laboratory gamma counter (P < 0.001). MFE-23-his scFv antibody localizes in CEA-producing carcinomas. The short interval between injection and operation, the lack of significant toxicity, and the relatively simple production in bacteria make MFE-23-his scFv suitable for RIGS.

Adult↗
PubMed1998

Side-to-side stapled anastomosis may delay recurrence in Crohn's disease.

PURPOSE: Perianastomotic recurrence after resection in Crohn's disease may be related to ischemia and subacute obstruction at the anastomosis. A technique designed to minimize these factors currently is being evaluated. METHODS: From 1984 to 1997 69 patients underwent resection and primary anastomosis for symptomatic Crohn's disease (17 jejunal or ileal, 72 ileocolic, and 7 colocolic resections). Of these, 42 patients underwent functional end-to-end anastomoses with the use of linear cutting staplers (Proximate 75 mm or GIA 228 80 mm) and 27 patients underwent end-to-end sutured anastomoses. RESULTS: In the stapled anastomosis group one (2 percent) patient required reoperation for recurrent symptoms at 46 months. Complications occurred in four (8 percent) patients (one enterocutaneous fistula, one wound infection, one abscess, and one ileus). There were no anastomotic leaks. The median postoperative stay was seven (range, 5-26) days. In the sutured anastomosis group 14 (43 percent) patients required 15 further resections for symptomatic recurrence at a median of 46 (range, 4-91) months. Complications occurred in six (17 percent) patients (two anastomotic leaks, two fistulas, one stricture, and one pulmonary embolus). The median postoperative stay was 10 (range, 6-28) days. CONCLUSIONS: Functional end-to-end stapled anastomoses after resection for Crohn's disease may be associated with fewer complications than sutured anastomoses and may delay reoperation for symptomatic recurrence. Further evaluation of the technique is indicated.

Adolescent↗
PubMed1994

Prospective randomized trial of Ivalon sponge versus sutured rectopexy for full-thickness rectal prolapse.

Ivalon sponge rectopexy is a safe reliable procedure in the management of rectal prolapse. Sutured rectopexy is simpler and avoids the use of foreign material. Sutured rectopexy is mandatory if synchronous resection is to be considered. Sixty-three patients (62 women) with full-thickness rectal prolapse were entered into a prospective randomized trial of Ivalon sponge rectopexy (31 patients) versus sutured rectopexy (32). Twenty patients (32 per cent) had coexistent incontinence (ten in each group). The operation was performed in the standard manner with a sutured rectangle of sponge or sutures alone placed along the length of the sacrum. Postoperative morbidity occurred in nine patients (14 per cent) of whom three underwent a sutured procedure and six Ivalon rectopexy: wound infection in three, chest infection in two, urinary tract infection in two and thromboembolism in two. There were no deaths within 30 days. At a median follow-up of 47 months prolapse had recurred in two patients (3 per cent), one in each group, 14 (22 per cent) suffered from incontinence (of whom five had undergone a sutured procedure), while 25 (40 per cent) had developed constipation (of whom 15 had received Ivalon rectopexy). The medium-term results of rectopexy by suture alone are equivalent to those obtained following the conventional Ivalon procedure. These data suggest that Ivalon rectopexy could now be abandoned.

Adult↗
PubMed1993

Crohn's disease and anastomotic recurrence: microvascular ischaemia and anastomotic healing in an animal model.

Microvascular injury and ischaemia may be factors in anastomotic recurrence after resection for Crohn's disease. This hypothesis was explored in a ferret model of multifocal intestinal infarction. At laparotomy, isolated loops of small intestine were injected intraarterially with styrene microspheres (test loop) or saline (control). At a second laparotomy 72 h later, test and control loops were divided and an end-to-end anastomosis performed between test loops (n = 2), test and control loops (n = 9) or control loops (n = 2). Abnormalities including chronic transmural inflammation, ulceration and granuloma formation were identified 2 weeks after the second operation in ten of the 11 surviving animals; changes were confined to the test loops and were more prominent adjacent to the anastomosis. No abnormalities were seen in control loops. The combination of two self-limiting ischaemic insults can produce a pattern of intestinal inflammation similar to that seen in anastomotic recurrence in Crohn's disease.

Anastomosis, Surgical↗
PubMed1993

Long-term results of large-dose, single-session phenol injection sclerotherapy for hemorrhoids.

PURPOSE: The aim of our study was to assess the medium to long-term outcome following single session large dose injection sclerotherapy for symptomatic hemorrhoids. METHODS: One hundred eighty-nine patients (male = 106, female = 83, median age, 51; range, 20-85 years) were assessed following single-session, large-dose (3 x 5 ml) phenol injection therapy. The most frequent complaint was bleeding (100 percent). RESULTS: At four-year follow-up, 53 patients (28.0 percent) were cured, 26 (13.7 percent) were improved, 35 (18.5 percent) remained unchanged, 59 (31.2 percent) deteriorated, and 16 (8.5 percent) required surgical intervention. Among the patients who were not cured, symptoms were minimal in 50 percent. Sclerotherapy was associated with a reduced incidence of bleeding (P < 0.05) but an increase in difficulty in perineal cleaning was observed (P < 0.05). CONCLUSION: Large-dose, single-session sclerotherapy provides only short-term benefits in the majority of patients with symptomatic hemorrhoids.

Adult↗
PubMed1991

Granulomatous vasculitis in Crohn's disease.

This study investigated a possible vascular origin for granulomas in Crohn's disease. Twenty-four consecutive resected specimens of small and large intestinal Crohn's disease were preserved by arterial perfusion-fixation with 10% formol saline, at mean arterial pressure (100 mm Hg). Fifteen specimens contained granulomas on routine examination of H&E-stained sections. These 15 specimens were examined in detail using a range of immunohistochemical staining techniques to identify vascular structures and granulomas. A total of 485 granulomas were found, 85% of which were identified as being directly involved in vascular injury. The majority (77%) of granulomas were deep to the mucosa; they were found most frequently in the submucosa (42%). The techniques used in this study enhanced the recognition of granulomatous vasculitis. The results suggest that the majority of granulomas in Crohn's disease form within walls of blood vessels. Vascular localization of granulomatous inflammation suggests that the intestinal microvasculature contains an early element in the pathogenesis of Crohn's disease.

Crohn Disease↗
PubMed1989

Pathogenesis of Crohn's disease: multifocal gastrointestinal infarction.

In a prospective study, specimens of resected small and large intestine from fifteen patients with Crohn's disease were prepared by heparin-saline vascular perfusion, followed by either resin casting of the mesenteric vascular supply and tissue maceration or glutaraldehyde perfusion-fixation, resin casting, and tissue clearance. The specimens were examined by macrophotography, histopathology, and either scanning or transmission electronmicroscopy. A pathogenetic sequence of events in Crohn's disease was seen--vascular injury, focal arteritis, fibrin deposition, arterial occlusion mainly at the level of the muscularis propria, followed by tissue infarction or neovascularisation. These features were confined to segments of intestine affected by Crohn's disease and did not occur in normal bowel. The findings suggest that Crohn's disease is mediated by multifocal gastrointestinal infarction. This pathogenetic process is compatible with many of the clinical features of Crohn's disease, and its recognition has important implications for the identification of the primary cause of the illness and advances in clinical management.

Cecum↗
PubMed1988

Resection for colorectal cancer in the very old: are the risks too high?

Altogether 277 consecutive patients aged 70 or more who were admitted for resection of colorectal cancer between 1975 and 1985 were studied. The postoperative complications and mortality in the 175 patients aged 70-79 were compared with those in the 102 patients aged 80 or more. The overall mortality was 11%. Mortality was significantly higher after resection in the older age group even when deaths from widespread malignancy were excluded from the analysis. After curative resection mortality was 2% (2/120) in the younger group and 7% (4/60) in the older group, but after palliative resection of tumours with local or distant spread mortality was significantly higher, at 21% (9/44) and 38% (12/32), respectively. An equal but high proportion of patients in both age groups suffered major complications, but complications caused significantly more deaths in the older group. The length of stay in hospital was not significantly different between the age groups. Patients should not be denied resection of a colorectal cancer because of age alone, especially if a curative operation is possible. The increased risk of death from major complications, particularly after palliative resection, should, however, be taken into account when an operation on patients over 80 is being considered.

Age Factors↗
PubMed1988

Measurement of cell kinetics in human tumours in vivo using bromodeoxyuridine incorporation and flow cytometry.

The proliferative potential of human solid tumours, in vivo, was investigated using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry (FCM). Patients with solid tumours from a variety of sites were injected with 500 mg BrdUrd, intravenously, several hours prior to biopsy or surgical excision. The labelling index (LI), duration of S-phase (Ts) and thus the potential doubling time (Tpot) could be measured within 24 h of sampling. The results show that both the LI and Ts vary greatly between tumours (Ts ranges from 5.8 to 30.7 h). However, within this study of 26 evaluable patients, tumours of the same tissue origin tended to have similar Ts values. Melanomas had the shortest Ts (8.8 h), nine patients with head and neck cancer had Ts values ranging from 5.8 to 18.8 h (median 12.5 h). The longest Ts values (24 h) were found in lung and rectum. The estimates of Tpot ranged from only 3.2 days in an oat cell carcinoma to 23.2 days in a lymphoma. The striking feature of the study was that 38% of the tumours had a potential doubling time of 5 days or less. We found no relationship between proliferation and histopathological differentiation or DNA ploidy. It should now be possible to assess the prognostic significance of pretreatment cell kinetic measurements which may, in the future, aid in the selection of treatment schedules for the individual patient.

Bromodeoxyuridine↗
PubMed1987

Cell kinetics of mouse kidney using bromodeoxyuridine incorporation and flow cytometry: preparation and staining.

The kidney is recognized as a dose-limiting tissue by certain radiation treatments. The relationship between the onset of compensatory proliferation in response to irradiation and the expression of functional damage is difficult to study because of the low cell turnover in slowly proliferating tissues. We report on a method to obtain a suitable cell preparation from mouse kidney for study by flow cytometry using the recently developed staining techniques for bromodeoxyuridine incorporation. The labelling index of 0.3% in untreated mouse kidney was easily measured because large numbers of cells could be analysed rapidly. We show that compensatory proliferation after unilateral nephrectomy remains elevated for up to 3 weeks after surgery. Using the BrdU/FCM technique we were able to measure the duration of the S phase in normal and nephrectomized kidneys which we found to be 8.5 hr in both cases. The estimates of potential doubling time were similar to the time scale observed to elapse before functional damage is observed in normal kidneys and those in which damage is precipitated by surgery.

Animals↗
PubMed1987

Colostomy or ileostomy after colorectal anastomosis?: a randomised trial.

Sixty one patients were entered in a randomised trial to compare transverse loop colostomy with loop ileostomy after a colorectal anastomosis thought to be at risk of dehiscence. Radiologically proven breakdown of the colorectal anastomosis occurred in 13% of these selected patients and most frequently in the colostomy group. Ileostomies functioned earlier than colostomies (P less than 0.001) but there was no other significant difference in outcome between the groups. In 52 patients intestinal continuity was restored by excision of the stoma within a month of construction with no difference in morbidity between the two groups. A loop ileostomy, closed as soon as the colorectal anastomosis has healed, is recommended as an alternative to transverse colostomy.

Aged↗
PubMed1986

Extramedullary haemopoiesis in the small bowel.

A patient with myelofibrosis developed repeated gastrointestinal haemorrhage from the small intestine, which was found to be infiltrated with extramedullary haemopoiesis. Nineteen months later he presented with subacute intestinal obstruction; radiology and laparotomy documented progressive infiltration of the small bowel. Histological examination of the resected terminal ileum showed patchy mucosal ulceration, with underlying submucosal and serosal extramedullary haemopoiesis.

Gastrointestinal Hemorrhage↗