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Biomedical subjects

P H Gordon

Publications and source records attributed to P H Gordon.

At least 19 recordsLinked to original sources
PubMed1997

Re-examination of clinical manifestations and response to therapy of fissure-in-ano.

PURPOSE: This study was designed to reassess clinical manifestations of fissure-in-ano, in particular, the frequency of constipation and rate of response to medical management. METHODS: Records of 876 patients with fissure-in-ano seen between February 1975 and December 1993 were reviewed. Information gathered included age, gender, site, symptoms, bowel habits, associated anorectal problems, response, failure, and recurrence rates. RESULTS: There were 439 women (51.1 percent) and 437 men (49.9 percent); mean age was 39.9 (range, 13.5-95) years. The fissure was located in the posterior mid line in 644 patients (73.5 percent), the anterior mid line in 144 patients (16.4 percent), both in 23 patients (2.6 percent), and only tenderness documented in 65 patients (7.4 percent). The fissure was located in the anterior midline in 12.6 percent of women and 7.7 percent of men. Dominant presenting symptoms included pain in 90.8 percent and bleeding in 71.4 percent of patients. Infrequent hard bowel movements (> or = 3 days) occurred in only 13.8 percent of patients. Mean follow-up was 26 (range, 0.5-215) months. A total of 44.7 percent of patients responded to nonoperative therapy, 60 percent of them in the first two months; of these, 18.6 percent developed recurrent symptoms. Of the latter group, 60 percent responded to further medical therapy, and 20 percent underwent a lateral internal sphincterotomy. Of the patients who initially did not respond to medical treatment (50.5 percent), lateral internal sphincterotomy was recommended. CONCLUSION: Anterior fissures are much more common in both men and women than previously reported, and constipation and hard bowel movement are not universally present in patients with fissure-in-ano.

Adult↗
PubMed1997

Bonded orthodontic retainers: the wire-composite interface.

The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. An in vitro model was developed to simulate the forces encountered at the wire/composite interface. No significant difference was detected between different multistrand wire types and diameters with regard to retention in composite. Wires were placed in one of three groups according to surface characteristics identified with scanning electron microscopy. Increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite. Thickness of composite greater than 1.0 mm overlying the wire may give little clinical advantage. Greater force was required to detach the wire from Concise Orthodontic (3M Unitek) than any other composite tested. In vitro abrasion resistance testing found Heliosit Orthodontic (Vivadent) and Right On (TP Orthodontics, Inc.) to have poor abrasion resistance, whereas Concise Orthodontic and Transbond (3M Unitek) had abrasion resistance comparable with restorative composites. Clinical recommendations are made based on these findings.

Adhesiveness↗
PubMed1996

Erroneous diagnosis corrected after 28 years. Not spinal muscular atrophy with ophthalmoplegia but minicore myopathy.

OBJECTIVE: To correct, after 28 years, the previously reported diagnosis of ophthalmoplegia in a patient with presumed childhood spinal muscular atrophy. DESIGN: Clinical follow-up, laboratory, electrophysiologic, and muscle biopsy data are provided. RESULTS: The findings of clinical follow-up examination, electrophysiologic tests, and histologic examination of muscle specimens led to a revised diagnosis of minicore myopathy. CONCLUSIONS: Spinal muscular atrophy was diagnosed in 1967, before histochemical techniques for examining muscle tissue and quantitative electromyography became widely available. Modern laboratory techniques later made the diagnosis of minicore myopathy possible. Progressive external ophthalmoplegia has been described in 24% of patients with minicore myopathy, but there have been only 7 reports of ophthalmoplegia with spinal muscular atrophy since 1954, and some of these diagnoses have been questioned.

Adult↗
PubMed1996

Immunohistochemical analysis of statin in colorectal adenocarcinoma, polyps, and normal mucosa.

PURPOSE: The search for an understanding of the kinetics of the malignant cell is an ongoing focus of research. The aim of the present study was to determine whether there were any differences in the expression of statin, a nonproliferation-specific nuclear protein, among different colorectal tissues and whether there is any relationship between statin presence and neoplastic aggressivity. METHODS: The study population consisted of specimens from 19 patients who underwent resection for carcinoma, one for villous adenoma, and seven for colonoscopic polypectomies. Tissue samples were taken from the center of the specimen and from mucosa 10 cm from the lesion. RESULTS: Statin immunoreactivity was evaluated by counting stained nuclei in ten randomly chosen fields, and percent of positive cells was calculated. Average percentage of statin-positive cells was 34.33 +/- 6.81 in the normal crypt, 44.42 +/- 7.28 for polyps, and 7.74 +/- 5.67 for carcinomas (significantly lower than normal mucosa and polyps; P < 0.001). CONCLUSION: Statin expression is dramatically diminished in invasive carcinoma tissue, but it did not help determine aggressivity with respect to Dukes stage.

Adenocarcinoma↗
PubMed1996

Long source-skin distance rectal irradiation technique: a review of results.

PURPOSE: This study reports the clinical outcome of fifteen patients with low rectal adenocarcinoma treated with the long source-skin distance (SSD) of endorectal irradiation technique. This method was designed at McGill University in 1986 as an alternative to the standard short SSD rectal irradiation that was developed by Papillon (Proc. R. Soc. Med. 66: 1179-1181, 1973). METHODS AND MATERIALS: Between April 1986 and May 1993, six females and nine males were treated with this technique. Fourteen patients were treated with curative intent and one woman for palliation. The median total dose was 85 Gy (range 60-135 Gy) in a median of 3 fractions (range 3-5) over a median treatment time of 5 weeks (range 2-9.5 weeks). RESULTS: With a mean follow-up of 39 months and a median of 24 months (range 3 months-8.7 years), actuarial overall survival and disease-free survival rates are 50.8% and 71.4%, respectively, at 8.7 years. No patients have died of recurrent disease, but one patient has distant metastatic disease. One patient treated with curative intent required an abdominoperineal resection for progressive disease. Treatments were tolerated well by all patients. Four patients required steroid enemas for localized proctitis for a short period of time. They all responded well and had complete resolution of symptoms. CONCLUSIONS: Our results are comparable with those in other reports in the literature. The complications are similar in type and frequency to other published series. The long SSD technique may be an acceptable alternative to the standard short SSD technique.

Adenocarcinoma↗
PubMed1996

Diagnosis in neuromuscular diseases.

The diagnosis of neuromuscular diseases can be challenging and successful in the majority of patients, due to advancements in electrophysiology, muscle and nerve biopsy immunohistochemistry, and cytogenetics. This article reviews diverse topics, highlighting these recent achievements, with an emphasis on how they affect the clinical and laboratory diagnosis of specific neuromuscular disorders.

Biopsy↗
PubMed1996

Results of local excision for rectal carcinoma.

OBJECTIVE: To determine the results peranal excision for rectal carcinoma. DESIGN: Retrospective case series. SETTING: A university-affiliated hospital. PATIENTS: Of 178 patients who presented for curative resection of rectal carcinoma between 1975 and 1993, 19 (10.7%) were deemed suitable for local excision. There were 10 men and 9 women with a mean age of 71.2 years. The follow-up ranged from 13 to 184 months. INTERVENTION: Peranal excision. MAIN OUTCOME MEASURES: Histologic differentiation, gross morphology, depth of invasion and size of the carcinoma, adequacy of margins of excision, complications of operation, rates of recurrence, results of salvage therapy and 5-year survival. RESULTS: There were no intraoperative complications. Postoperative complications included urinary retention (one patient) and bleeding (one patient). There were five local recurrences (26%). Salvage operations were performed in three (60%) patients and were successful in two of them. The 5-year cancer-specific survival rate was 82%. The recurrence rate was higher in patients with inadequate margins of excision and ulcerative lesions. Neither size nor grade of the carcinoma correlated with recurrence. CONCLUSIONS: Local excision of rectal carcinoma can be performed successfully in selected patients. Diligent follow-up is required, because up to 60% of local recurrences can be treated successfully.

Aged↗
PubMed1995

Effect of 5-fluorouracil and leucovorin on the integrity of colonic anastomoses in the rat.

PURPOSE: This study was designed to determine the effects of 5-fluorouracil and leucovorin on the healing of colonic anastomoses and assess the safety of conducting a colonic resection and anastomosis during and shortly after a course of this chemotherapy in a rat model. METHODS: Fifty-six male Wistar rats, weighing 200 to 250 gm, were divided into four groups, each consisting of 14 animals. Animals in Group I (control group) underwent colon resection and primary anastomosis. Animals in Group II received 10 mg/kg intravenous 5-fluorouracil and 10 mg/kg leucovorin once a week for four weeks and then underwent the same operation. Animals in Groups III and IV received the same drug dosage for six weeks and were operated at different intervals: Group III at one week and Group IV at two weeks after completion of chemotherapy. Within each group, one-half of the animals were sacrificed on the third postoperative day and one-half on the seventh postoperative day, and anastomotic bursting pressure measurements were performed. RESULTS: At three and seven days, mean bursting pressure of the anastomoses were determined: 98 mmHg and 180.7 mmHg in Group I, 95 and 197.8 in Group II, 85.7 and 189.2 in Group III, and 98.6 and 179.2 in Group IV, respectively. There was no significant difference in bursting pressure between treated animals and controls by the third postoperative day or by the seventh day. The burst occurred at the anastomosis in all specimens tested on the third postoperative day and in the bowel wall adjacent to the anastomosis in all specimens tested on the seventh postoperative day. CONCLUSION: This study demonstrates that the above regimen of chemotherapy has no effect on the healing of colonic anastomoses and that surgery can be performed safely during and shortly after this regimen of chemotherapy.

Anastomosis, Surgical↗
PubMed1995

Proliferative activity at rectal anastomoses performed with various suture materials. An experimental study.

BACKGROUND: Suture line recurrence continues to be an important cause of failure following curative resection for colorectal carcinoma. Our aim was to determine whether the nature of the suture material used affected the proliferative activity of colonic crypt cells at the anastomosis. METHODS AND MATERIALS: Sprague-Dawley rats were randomized into one control and three experimental groups. In each experimental group the proximal 2 cm of rectum were resected and anastomoses constructed with titanium clips, interrupted 6-0 Vicryl (Ethicon, Inc., Somerville, NJ), and interrupted 6-0 silk. Control animals had a sham operation. One-quarter of each group of rats were killed at 14, 30, 60, and 90 days. Each animal received intraperitoneal tritiated thymidine 30 minutes before death. Each anastomosis was harvested, and longitudinally oriented crypts were analyzed for the total number and position of labeled cells at five equal distances from the anastomosis. Random crypts were studied in the control group. RESULTS: Labeling indices were increased in almost all experimental groups at days 14, 30, 60, and 90. There were no persistent, statistically significant differences in labeling indices among the various suture materials. CONCLUSION: The type of suture material used did not significantly affect the proliferative rate in this animal model.

Anastomosis, Surgical↗
PubMed1995

Expression of proliferation-specific genes in the mucosa adjacent to colon carcinoma.

BACKGROUND: One of the main concerns in colon carcinoma therapy is local recurrence of the malignancy at the site of resection. Previous studies have shown that morphologically normal-appearing mucosa adjacent to colon carcinoma is different from mucosa distant from carcinoma. Mucosa adjacent to a carcinoma is characterized by crypt lengthening, cell hypertrophy, and change in production of mucopolysaccharides from sulfomucin in normal mucosa to sialomucins in carcinomas and adjacent mucosa. Recently there have been reports suggesting that there is an upward extension of the proliferative compartment in colonic crypts of this adjacent mucosa. METHODS: Immunoblot analysis using antibodies to retinoblastoma, statin, c-Fos, c-Jun, and Cdc-2 proteins was used for our study on the expression of early cell cycle genes in carcinoma and its adjacent mucosa. In all, 15 tissue samples obtained from patients with colon carcinoma were analyzed. Tissue specimens were collected and immediately dissected as tumor, 0 to 1, 1 to 2, 2 to 3, 3 to 4, and 4 to 5 cm from the primary lesion. Dissected pieces were homogenized separately and subjected to immunoblot analysis. RESULTS: We found upregulation of c-Fos, c-Jun, and Cdc-2 expression in carcinoma and adjacent mucosa up to 4 cm from the edge of the carcinoma. The phosphorylated form of retinoblastoma is present in the carcinoma as well as in adjacent mucosa up to 4 cm from the margin of the carcinoma. Furthermore, we observed that the level of statin, a nonproliferation-specific nuclear protein, is very low in the primary lesion and in adjacent mucosa up to 3 cm. CONCLUSIONS: These results indicate that adjacent tissue up to 3 to 4 cm from the carcinoma has elevated levels of expression for cell cycle traverse-associated genes and down-regulation of nonproliferation-specific gene expressions such as statin. This imbalance indicates that within 3 to 4 cm from the edge of the carcinoma, colonic epithelial cells are already abnormal and may be in the hyperproliferative and preneoplastic state, susceptible to further steps leading to eventual malignant transformation.

Carcinoma↗
PubMed1995

An investigation into the fluoride release of a variety of orthodontic bonding agents.

The purpose of this study was to compare the fluoride release from a variety of orthodontic bonding agents. Fluoride release into de-ionized water was measured over a 20-week period. Material based on the fluoride exchange resin was also tested in a saline solution. Fluoride release from a variety of orthodontic bonding agents was compared and the amount of release found to be highly variable. Glass ionomer-based materials showed substantially greater fluoride release when compared with resin-based materials. The presence of anions (Cl-) did not improve the release from fluoride exchange resin. Glass ionomer/resin hybrid material (Vitrabond) released the greatest amount of fluoride.

Adhesives↗
PubMed1995

The effect of artificial saliva on the frictional forces between orthodontic brackets and archwires.

The effect of artificial saliva on the static and kinetic frictional forces of stainless steel (Dentaurum) and polycrystalline ceramic (Transcend) brackets in combination with 0.018-inch round and 0.019 x 0.025-inch Edgewise archwire sizes and stainless steel, nickel-titanium and beta-titanium archwire materials, under a constant ligature force were investigated. In all cases, artificial saliva had the effect of increasing the frictional force when compared with the dry state.

Ceramics↗
PubMed1995

An investigation to estimate the fluoride uptake adjacent to a fluoride-releasing bonding agent.

Decalcification of the teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that bonding agents which release fluoride could supply it to the area of the tooth most at risk from decalcification. The aim of this study was to estimate uptake by enamel adjacent to a fluoride releasing bonding agent. Acid etch biopsies were used to estimate the concentration of fluoride in enamel adjacent to brackets bonded with Vitrabond and Geristore. Results indicate that there was a significant increase in the concentration of fluoride in enamel adjacent to Vitrabond. The clinical significance of the increase in the concentration of fluoride adjacent to Vitrabond and the mechanism by which fluoride moves from the material into the enamel remain unclear.

Acid Etching, Dental↗
PubMed1995

The effect of sandblasting on the retention of first molar orthodontic bands cemented with glass ionomer cement.

This study examined the effect of sandblasting, in vitro, on the bond strength and survival time of first molar orthodontic bands. Survival time was assessed following simulated mechanical fatigue in a ball mill. The amount of cement left attached to the band after debanding was also assessed. In addition, the effect of sandblasting on the failure rate of 320 first molar bands cemented in 107 patients was examined in a half-mouth trial. Ketac-cem, mixed according to manufacturers' instructions was used as the luting agent for both laboratory and clinical trials. In vitro, sandblasting increased bond strength by 27 per cent (P < 0.01) and produced a three-fold increase in the median survival time relative to the untreated sample (P < 0.001) in the ball mill experiment. Sandblasting resulted in more cement remaining on the band rather than on the tooth enamel after band removal. In vivo, sandblasting reduced the clinical failure rate of the first molar bands (P < 0.001).

Adolescent↗
PubMed1995

An ex vivo study of self-, light-, and dual-cured composites for orthodontic bonding.

It was postulated that using a dual-cured composite to bond orthodontic brackets could result in bond strengths comparable with those of chemically-activated materials and higher than those for light-activated materials. The shear bond strength of four composite resins used to attach mesh-backed orthodontic brackets was measured at 24 hours and following mechanical insult in the ball-mill. Analysis of variance and an SNK range test showed that at 24 hours Dual-cured Porcelite gave a significantly higher mean bond strength than the other materials (P < 0.05). However, following ball-milling the mean bond strength for Right-on was apparently significantly higher than that of the other materials. (P < 0.05). In this study, the mode of bond failure is also analysed and the use of Weibull analysis in bond strength testing is described.

Acid Etching, Dental↗