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Biomedical subjects

D Morton

Publications and source records attributed to D Morton.

At least 37 records · Page 2Linked to original sources
PubMed1999

Comparison of blue dye and probe-assisted intraoperative lymphatic mapping in melanoma to identify sentinel nodes in 100 lymphatic basins.

OBJECTIVE: To determine whether combining isosulfan blue dye with a radiopharmaceutical agent will increase intraoperative detection of sentinel nodes (SNs) in patients with early-stage melanoma. PATIENTS AND DESIGN: Clinical trial with a consecutive sample. Eighty-seven patients with clinical stage I melanoma underwent preoperative lymphoscintigraphy with 1 of 3 radiopharmaceutical agents to identify the lymphatic basin and the site of the SN. All patients subsequently underwent intraoperative lymphatic mapping and selective lymph node dissection (SLND) with isosulfan blue dye and a radiopharmaceutical agent. A handheld gamma probe determined the radioactive counts over the draining lymph node basins and individual blue-stained lymph nodes before (in vivo) and after (ex vivo) their removal. An irrelevant body site was used as the denominator of a count ratio by which absolute counts were standardized for comparison. Completion lymphadenectomy was undertaken in patients whose SLND specimen had histopathologic evidence of tumor cells. SETTING: Tertiary care cancer center. INTERVENTION: Lymph node sampling. MAIN OUTCOME MEASURE: Accuracy of SN detection by blue dye and radiopharmaceutical techniques. RESULTS: Preoperative lymphoscintigraphic images identified 100 lymph node basins and 135 lymph nodes in 87 patients. All 3 radiopharmaceutical agents were equally effective in imaging the SN before surgery. During SLND, we identified and removed 136 blue-stained and radioactive (hot) SNs and 8 additional non-blue-stained hot nodes from 98 basins (98.0%). Of the 144 excised lymph nodes, 132 nodes (91.7%) from 83 basins had either an in vivo- or an ex vivo-background count ratio of 2:1 or more and 125 nodes (86.8%) from 77 basins had a count ratio of 3:1 or more. Twelve blue-stained SNs had count ratios of less than 2:1. Seventeen SNs (11.8%) from 15 basins contained metastases: 16 were identified with blue dye and probe and 1 was identified with blue dye alone. Four (1.1%) of 377 non-SNs excised during completion lymphadenectomy contained metastases. There have been no lymph node recurrences during mean follow-up of 16.3 months (range, 7-42 months). CONCLUSIONS: The blue dye technique remains the criterion standard for SLND in melanoma. The addition of a radiopharmaceutical tracer serves as a useful adjunct to the visualization of blue-stained SNs.

Female↗
PubMed1999

Ursodeoxycholic acid has no influence on function after restorative proctocolectomy in ulcerative colitis.

BACKGROUND: Poor pouch function is associated with impaired bile acid absorption and increased faecal loss of bile acids. Bile acid replacement therapy might therefore be of clinical benefit, provided that diarrhoea is not aggravated by therapy. AIM: To investigate the role of exogenous bile acid therapy in patients with poor pouch function after restorative proctocolectomy for ulcerative colitis. PATIENTS AND METHODS: Twenty ulcerative colitis patients with poor pouch function (score > 4 on a 12-point score) were recruited for inclusion to a prospective, randomized, double-blind crossover, placebo-controlled trial of ursodeoxycholic acid (10 mg/kg per day in two divided doses for 1 month). RESULTS: A total of 16 patients completed the study. There was no significant difference in the functional score or bowel frequency following treatment irrespective of whether the active treatment was given before or after placebo. CONCLUSIONS: We conclude that ursodeoxycholic acid given over 4 weeks had no influence on functional score or bowel frequency after restorative proctocolectomy for U.C.

Adult↗
PubMed1999

Epstein-barr virus nuclear antigen 1 sequences in endemic and sporadic Burkitt's lymphoma reflect virus strains prevalent in different geographic areas.

The Epstein-Barr virus (EBV) nuclear antigen EBNA1 is the only viral protein detectably expressed in virus genome-positive Burkitt's lymphoma (BL); recent work has suggested that viral strains with particular EBNA1 sequence changes are preferentially associated with this tumor and that, within a patient, the tumor-associated variant may have arisen de novo as a rare mutant of the dominant preexisting EBV strain (K. Bhatia, A. Raj, M. J. Gutierrez, J. G. Judde, G. Spangler, H. Venkatesh, and I. T. Magrath, Oncogene 13:177-181, 1996). In the present work we first study 12 BL patients and show that the virus strain in the tumor is identical in EBNA1 sequence and that it is matched at several other polymorphic loci to the dominant strain rescued in vitro from the patient's normal circulating B cells. We then analyze BL-associated virus strains from three different geographic areas (East Africa, Europe, and New Guinea) alongside virus isolates from geographically matched control donors by using sequence changes in two separate regions of the EBNA1 gene (N-terminal codons 1 to 60 and C-terminal codons 460 to 510) to identify the EBNA1 subtype of each virus. Different geographic areas displayed different spectra of EBNA1 subtypes, with only limited overlap between them; even type 2 virus strains, which tended to be more homogeneous than their type 1 counterparts, showed geographic differences at the EBNA1 locus. Most importantly, within any one area the EBNA1 subtypes associated with BL were also found to be prevalent in the general population. We therefore find no evidence that Burkitt lymphomagenesis involves a selection for EBV strains with particular EBNA1 sequence changes.

Africa, Eastern↗
PubMed1999

Stereotactic radiosurgery in the treatment of metastatic disease to the brain.

We review 190 consecutive patients with 434 metastatic tumors treated by gamma knife stereotactic radiosurgery, from August 1994 to February 1999. Median actuarial survival for all patients was 34 weeks. Factors correlated with significantly improved survival included controlled systemic disease and nonmelanoma histology. We found that no significant survival benefit could be discerned from adjuvant whole brain radiotherapy in this patient group. Survival was not statistically different for patients initially presenting with 1-4 metastases at initial treatment.

Brain Neoplasms↗
PubMed1998

Evaluation of resilient abutment components on measured strain using dynamic loading conditions.

STATEMENT OF PROBLEM: Factors that affect transmission of strain from prostheses to bone may affect the long-term success of loaded implants. Current in vitro models are theoretically predictive (finite element modeling) or facsimile (photoelastic) in nature. A more clinically relevant in vitro model for strain evaluation should be investigated. PURPOSE: This study attempted: (1) to validate a human cadaver bone model for vitro measurement of cortical bone strain, and (2) to evaluate the effect on cortical strain measurements of a resilient plastic component incorporated within a titanium implant in response to variable dynamic loading. MATERIAL AND METHODS: Two IMZ (Interpore International) abutment alternatives were used: the titanium Abutment Complete and the polyoxymethylene Intra-mobile Element. The model system consisted of two implants placed in unfixed human cadaver ulna bone to simulate an implant bound edentulous region. Four biaxial rosette strain gauges simultaneously recorded cortical bone strain immediately mesial and distal to each implant. During experimentation a simulated prosthetic framework supported by either titanium or polyoxymethylene abutments was dynamically loaded 6 min from the terminal abutment along a cantilever extension. Cyclic nominal peak loads were applied with a materials testing machine at 20-N intervals from 20 to 200 N at a crosshead speed of 5 mm/minute. The protocol allowed frequency of load application to vary. A Newtonian linear correlation (r2 > or = 0.98) between load application and strain output was determined for each gauge position except for the terminal gauge located opposite the cantilever. RESULTS: Cortical strains recorded were within reported physiologic ranges involved in bone modeling and remodeling. Further, the polyoxymethylene abutment components did not result in reduction of peak microstrain at any gauge position. The Intra-mobile Element abutments, however, did increase the time required to complete 10 loading cycles when compared with the titanium Abutment Complete abutments for the crosshead speed and ultimate loads evaluated. CONCLUSIONS: Results indicate the cadaver bone behaved in an elastic manner within the load range evaluated, and as such represents a viable in vitro experimental model. Under these conditions, polyoxymethylene abutment components do not affect measurable bone strain in response to variable loading when compared with titanium.

Bone and Bones↗
PubMed1998

Pantoprazole-based 10-day triple therapy is effective in Helicobacter pylori eradication.

AIM: To investigate the efficacy of a short course of pantoprazole-based triple therapy in Helicobacter pylori eradication in a single-centre pilot study. METHODS: Patients with active or healed duodenal ulcer or with gastric erosions or gastritis, all of whom were H. pylori-positive, received 10 days of twice-daily open treatment with pantoprazole 40 mg, plus clarithromycin 250 mg and tinidazole 500 mg. H. pylori was assessed at entry and 28-35 days after the end of treatment by rapid urease test (at entry only), culture and antimicrobial sensitivity, histology and 13C urea breath test. The criterion for eradication was a negative result in all three tests. RESULTS: Seventy patients were treated, of whom four were excluded from analysis due to major deviations from the study protocol. Eradication of H. pylori was achieved in 57/66 patients (per protocol analysis 86% (95% CI: 78-95%)) and was higher in patients with organisms sensitive to nitroimidazole before treatment (sensitive: 47/53 (89%), insensitive: 10/13 (77%)). There was marked reduction in acute gastritis throughout the stomach while chronic gastritis decreased only in the corpus. Healing was achieved in all 24 patients with active duodenal ulcer. Treatment was complied with; only one patient missed one of the 20 doses. Adverse events were of mild or moderate intensity and did not require withdrawal from treatment. CONCLUSION: A short course of pantoprazole-based triple therapy is well tolerated and effective in eradicating H. pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

Quality of life after pouch excision.

BACKGROUND: Pouch excision is a devastating experience for patients having restorative proctocolectomy for ulcerative colitis. METHODS: The quality of life among patients having pouch excision for ulcerative colitis was compared with that in those having proctocolectomy and ileostomy for ulcerative colitis using a validated standardized self-administered questionnaire. RESULTS: After pouch excision patients (n = 9) had more troublesome bowel symptoms (mainly from liquid stoma output) than those in the proctocolectomy group (n = 14) (mean(s.d.) score 5.64(0.92) versus 6.13(0.37), P = 0.03). However, the mean scores for the other parameters (systemic symptoms, functional, social and emotional impairment) did not differ significantly. CONCLUSION: Patients having pouch excision for ulcerative colitis have more liquid ileostomy loss but a comparable quality of life to those treated by standard proctocolectomy and ileostomy.

Activities of Daily Living↗
PubMed1998

Spaceflight and development of immune responses.

The NIH.R1 Space Shuttle experiment was designed to study the effects of spaceflight on rodent development. Pregnant rats were flown on the Space Shuttle for 11 days, and pregnant control rats were maintained in animal enclosure modules in a ground-based chamber under conditions approximating those in flight. Additional controls were in standard housing. The effects of the flight on immunological parameters of dams, fetuses, and pups were determined. Blastogenesis of spleen cells in response to mitogen was inhibited in flown dams but was not inhibited in cells from their pups. Interferon-gamma production by spleen cells showed a trend toward inhibition in flown dams but not in their pups. The response of bone marrow cells to colony-stimulating factor showed a trend toward inhibition after spaceflight in dams, but the response of fetus and pup liver cells was not inhibited. Total serum IgG was not affected by spaceflight. None of the examined immune parameters that were altered in rat dams after spaceflight was found to be altered in their offspring.

Animals↗
PubMed1997

Results of restorative proctocolectomy in the elderly.

Twenty eight of 227 patients undergoing restorative proctocolectomy for inflammatory bowel disease, familial adenomatous polyposis or functional disease were over the age of 50 years: ages 50 to 60 (n = 13), 60 to 70 (n = 10), and over 70 (n = 5). Major complications occurred in 5 patients over the age of 50 (18%) compared with 43 patients under the age of 50 (23%). Three patients above the age of 50 had their pouch excised (11%) compared with 23 under the age of 50 (12%). Functional outcome was assessed with a 12 point symptom score. This was similar in all age bands: under 50 years (mean = 2.2; sd +/- 2.2; n = 109), 50 to 60 years (mean = 2.5; sd +/- 2.5; n = 12), 60 to 70 years (mean = 2.8; sd +/- 2.3; n = 7) and over 70 years (mean = 4.0; sd +/- 3.7; n = 5): P > 0.05). When analysed for ulcerative colitis alone, no significant differences were seen between the two age groups. Restorative proctocolectomy in the elderly gives results which are comparable to the younger population.

Adenomatous Polyposis Coli↗
PubMed1997

Intraoperative lymphatic mapping for early-stage melanoma of the head and neck.

BACKGROUND: We previously reported dye-directed intraoperative lymphatic mapping and selective sentinel lymphadenectomy for primary cutaneous melanomas draining to the neck lymph nodes. In this study we determined whether combining the dye with a radiopharmaceutical agent would enhance our rate of sentinel node detection. METHODS: One hundred seventeen patients with primary cutaneous melanomas of the upper chest and head and neck underwent preoperative cutaneous lymphoscintigraphy to confirm lymphatic drainage to neck nodes, followed by intraoperative lymphatic mapping and sentinel lymphadenectomy. In 94 cases, isosulfan blue dye was injected at the primary site; in the remaining 23 cases, a 1:3 mixture of radiopharmaceutical and dye was injected, and a hand-held probe was used to determine the radioactive counts. RESULTS: Preoperative cutaneous lymphoscintigraphy identified 129 drainage basins; 12 patients (10%) had dual-basin drainage. During intraoperative lymphatic mapping and sentinel lymphadenectomy, 183 sentinel nodes were identified and excised from 120 basins (1.5 nodes/basin). The blue dye alone identified sentinel nodes in 93 of 101 basins (92%). The probe identified sentinel nodes in 28 of 28 basins, only one of which failed to reveal blue-staining sentinel nodes; thus, the probe plus dye identified sentinel nodes in 27 of 28 basins (96%). Histopathologic analysis revealed metastasis in sentinel nodes from 11 patients (12%) who underwent sentinel lymphadenectomy with blue dye alone and in 3 patients (13%) who underwent sentinel lymphadenectomy with dye plus probe. There were no same-basin recurrences over a mean follow-up of 46 months (range 1 to 125). CONCLUSIONS: Selective sentinel lymphadenectomy is a highly accurate method of staging the regional nodes in patients with primary tumors of the head and neck. Although we initially demonstrated the utility of this technique with blue dye alone, our results now suggest that the combination of dye and radiopharmaceutical may be a more sensitive method to detect sentinel nodes.

Coloring Agents↗
PubMed1997

Blunt intestinal injury in children: the role of the physical examination.

PURPOSE: Although blunt intestinal injury in children is uncommon, prompt recognition and treatment is imperative. Because the best method for diagnosis remains undetermined, the authors reviewed their experience with this injury in children to determine the most reliable diagnostic method and to identify factors associated with treatment delays. METHODS: From January 1989 through December 1995, 2,284 children were admitted to the level I trauma center after sustaining blunt abdominal trauma. Of these, 32 (1.4%) had intestinal injury confirmed during laparotomy. Each case was reviewed with particular attention to the initial physical examination, abdominal computed tomography (CT) scan, laparotomy observations, complications, and the hospital at which the child was initially treated, if applicable. Fisher's Exact test and Wilcoxon's rank sum test were used for statistical analyses, with P < .05 considered significant. RESULTS: Twenty-five patients (78%) had major intestinal injuries that required repair or resection; seven had minor intestinal injuries only. Two-thirds of the 32 were restrained passengers in motor vehicle crashes. The initial physical examination was suggestive of intestinal injury in 94% of children. Twenty-one children (84%) with major bowel injuries had diffuse abdominal tenderness at the time of initial physical examination, and only one of the seven (14%) with minor intestinal injury had generalized tenderness (P = .0014). Sixteen of 21 restrained passengers had seat-belt ecchymoses, and 13 of the 16 sustained major intestinal injuries. Only 1 of 13 abdominal CT scans performed was diagnostic of intestinal injury. Ten of 12 patients (83%) who underwent delayed laparotomy (more than 12 hours after injury) were initially evaluated at hospitals without trauma center designation; whereas 6 of the 20 nondelayed patients were evaluated at these hospitals (P = .0091). All four major complications occurred in the delayed group. CONCLUSION: The authors conclude that signs suggestive of major intestinal injury are present in children at the time of initial physical examination or shortly thereafter. The decision to operate can be based on this examination alone in the pediatric population. Abdominal CT scan is not reliable for the diagnosis of blunt intestinal injury in children. To expedite diagnosis and treatment, children who sustain blunt abdominal trauma should be examined immediately by a physician experienced in pediatric trauma care or be transferred to a designated trauma center where this service is available.

Accidents, Traffic↗
PubMed1997

An unusually severe phenotype for familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is a dominantly inherited predisposition to the development of many hundreds to thousands of adenomatous polyps of the colon. The mean age of onset is around 15 years, symptoms may arise in the third decade, and the median age for the development of colonic cancer is 35-40 years. Prophylactic colectomy reduces the risk of death from colorectal cancer to such an extent that late sequelae such as upper gastrointestinal tumours have become the main cause of mortality in appropriately managed patients. The age at which colonic surveillance begins reflects the natural history of the disease. Onset of polyp formation and cancer in childhood is very unusual, but has recently been associated with a specific mutation at codon 1309 in exon 15 where a more severe phenotype is sometimes observed. The case histories of two families are reported in which there is childhood onset of polyps in the youngest generation and in one case a carcinoma, in whom mutations have been identified in exon 11 of the APC gene. Several other affected relatives were diagnosed at ages ranging from 5-48 years, some already with a cancer at the time of first screening. Since the aim of screening for colonic polyps is prevention of colonic cancer, family members at risk should be offered genetic assessment and direct mutation testing where this is possible, usually in the early teens. In the absence of a genetic test (the situation in about one third of families) or in a known gene carrier, annual colonoscopy examination is advised from the same age. Clinicians should take note of the family history and be prepared to consider much earlier intervention if symptoms occur in a child with a family history of FAP. Where childhood onset of polyps has occurred, other children at risk in the family must be offered earlier genetic testing and endoscopic surveillance.

Adenomatous Polyposis Coli↗
PubMed1997

Studies on the gastric mucosal microcirculation. 2. Helicobacter pylori water soluble extracts induce platelet aggregation in the gastric mucosal microcirculation in vivo.

BACKGROUND: The exact mechanisms by which Helicobacter pylori infection results in gastric mucosal injury are unclear. AIMS: To assess in vivo whether H pylori extracts could initiate an inflammatory response in the rat gastric mucosal microcirculation. METHODS: Extracts of H pylori, Escherichia coli, or distilled water were administered topically to the gastric mucosa of anaesthetised animals. Fluorescence in vivo microscopy assessed macromolecular leakage of labelled albumin from mucosal vessels, leucocyte adherence/rolling, and platelet activity for 90 minutes. RESULTS: H pylori induced increases (p < 0.001) in adherent platelet thrombi and circulating platelet emboli after five and 15 minutes respectively. Adherent platelet thrombi (mean of four per field of view) remained significantly increased throughout the experiment, but circulating emboli (maximum of five at 30 minutes) decreased with time. Leucocyte adherence did not occur although early transient rolling was observed. An 11% increase (p < 0.02) in albumin leakage occurred after five minutes only. The induction of platelet aggregation was only observed following H pylori administration. CONCLUSION: This in vivo study demonstrated the ability of H pylori extracts to promote platelet aggregation within gastric mucosal microvessels. Recruitment of leucocytes was not observed. The results suggest that the early events associated with H pylori infection are platelet aggregation with perhaps subsequent leucocyte recruitment by activated platelets.

Animals↗
PubMed1996

A model to assess the usefulness of performance indicators.

This paper describes the Perception-Action-Impact (PAI) model used for testing the usefulness of health care organization performance indicators, and reports preliminary data in support of this model. Two hundred and ninety six hospitals contributed 500,000 obstetrical cases, and responded to surveys to assess various aspects of indicator usefulness. Domains of interest that were assessed include relevance of the measures, whether the measures identified opportunities for improvement, whether the health care organization took any action in response to the data, health care organizational structure for data use, and methods for dissemination of the indicator data. Findings from this study provide support for the PAI model. Consequently, perceptions regarding the indicators apparently have a significant impact on the usefulness of the data. When action was taken in response to the indicator data, a positive impact on patient care processes and outcomes was the typical result. Additional research is needed in the areas of data dissemination effectiveness, and the impact of attitude change on the use of performance measures.

Analysis of Variance↗