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Biomedical subjects

M G Robinson

Publications and source records attributed to M G Robinson.

At least 19 recordsLinked to original sources
PubMed2000

Isotopic synovectomy with P-32 in paediatric patients with haemophilia.

Isotopic synovectomy is being proposed as an option in the treatment of patients with haemophilic arthropathy. We present our experience with 11 paediatric patients who underwent 17, P-32 isotopic synovectomies for chronic haemophilic arthropathy. P-32 was injected into the joint per protocol, approved by the institutional review board. All our patients were male. Nine were factor VIII and two were factor IX deficient. The following joints were treated: ankle (n=10 procedures), elbow (n=5) and knee (n=2). The first procedure was performed on December 1993. None were human immunodeficiency virus positive. Mean age at the first procedure was 10.8 years (range, 5.2-15.2 years). Mean pretreatment joint clinical scores using the World Federation of Hemophilia guidelines for the ankle was 5.5 (SD +/- 2.3), the elbow 4.2 (+/-2.5), and knee 5.5 (+/-3.5); the corresponding post-treatment scores were 2.6 (+/-2.0), 1.4 (+/-0.5) and 2.5 (+/-3.5) respectively. Presynovectomy mean radiological scores using the Pettersson method were: ankle 1.8, elbow 1.8, and knee 1.5. A scoring system used in our centre for evaluating joints using magnetic resonance imaging (MRI) gave the following mean pretreatment scores: ankle 9.5, elbow 8.4, and knee 5.0. A marked decrease (an 80-100% decrease) in bleeding was seen in 13 of 17 procedures, and a moderate decrease (51-79% decrease) in two procedures, accounting for 85% reduction in bleeding into the target joints. The procedure was well tolerated and no untoward side-effects were noted as of May 1999, with a median follow-up of 40 months (range 19-65 months). None had any clinical evidence of cancer. Three patients had their joints retreated [elbow (one), ankle (two)]. These procedures were also well tolerated. In conclusion, in our study, isotopic synovectomy using P-32 appears to be feasible, safe and efficacious in the treatment of haemophilic arthropathy in paediatric patients who have been followed for a median of 40 months. As previously shown, MRI appears to give more detailed information about joint arthropathy than plain radiographs.

Adolescent↗
PubMed1997

Double-blind, placebo-controlled study of ranitidine for gastroesophageal reflux symptoms during pregnancy.

OBJECTIVE: To determine whether ranitidine (Zantac) taken once or twice daily is effective for relieving symptoms of gastroesophageal reflux among pregnant women who had failed conservative measures. METHODS: Volunteers with heartburn despite antacids were sought among our obstetrics clinic population for this double-blind, placebo-controlled, triple crossover trial. After a baseline week, 20 patients were randomized to receive the three following weekly regimens: ranitidine 150 mg twice daily, placebo in the morning and ranitidine 150 mg in the evening, or placebo twice daily. Daily scores on symptom diaries, global assessments, and number of antacids taken were compared among the 18 patients completing the study. RESULTS: The twice-daily dosage of ranitidine was the only regimen found to reduce heartburn symptoms when compared with the baseline (P < .001) or a placebo (P < .01). Compared with ranitidine taken once daily, the twice-daily dosing prompted less need for antacid tablets compared with the placebo (P < .05 versus P > .05) and to the baseline (P < .001 versus P < .05). The average reduction of heartburn severity using twice-daily ranitidine was 55.6% when compared with baseline (95% confidence interval [CI] 34.8%, 76.5%) was 44.2% when compared with placebo (95% CI 15.4%, 72.9%). CONCLUSION: This study indicates the efficacy of ranitidine 150 mg taken twice daily, rather than once daily, for relief of gastroesophageal reflux symptoms during pregnancy.

Cross-Over Studies↗
PubMed1996

Reversal of CNS-prophylaxis-related leukoencephalopathy after CSF shunting: case histories of identical twins.

We report the case histories of identical twin brothers who developed concordant acute lymphoblastic leukemia at the age of 4 years and who later developed leukoencephalopathy and hydrocephalus related to central nervous system prophylaxis by, in the first case intrathecally administered methotrexate and, in the second by intrathecally administered methotrexate and cranial irradiation. The delayed encephalopathy developed 9 and 22 months respectively after the first dose of intrathecal methotrexate. Both patients underwent cerebrospinal fluid shunting mainly for their hydrocephalus. The imaging studies have shown that both hydrocephalus and leukoencephalopathy have improved significantly after ventriculoperitoneal shunt insertion. We review the pathophysiology of prophylaxis-related encephalopathy in leukemia patients and summarize its clinical, histological, and radiological characteristics. We also discuss the possible contribution of altered cerebrospinal fluid dynamics in the development of leukoencephalopathy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Mandibular reconstruction using a titanium plate: the impact of radiation therapy on plate preservation.

PURPOSE: To evaluate the soft tissue and bone tolerance of radiation therapy (RT) in patients undergoing radical composite resection and mandibular reconstruction using a bridging titanium plate with myocutaneous flap closure. METHODS AND MATERIALS: From 1990 to 1994, 47 patients with primary or recurrent oral cavity or oropharyngeal carcinomas were treated with radical composite resection and mandibular reconstruction using a bridging titanium plate with myocutaneous flap closure. Eleven patients received no RT (no RT), 10 patients received RT greater than 10 months from the time of surgery (remote RT), and 26 patients received RT within 12 weeks of surgery (perioperative RT). The radiation dose to the reconstructed mandible ranged from 45 to 75 Gy (median 63 Gy). The effect of the titanium plate on the radiation dose was measured using film dosimetry and soft tissue and bone-equivalent materials. The median follow-up was 17 months (range: 3-50 months). RESULTS: Late complications included four patients with osteomyelitis or necrosis, two plate exposures requiring flap revision, one chronic infection, two cases of chronic pain, two fistulae, and one case of trismus and malocclusion. The crude incidence of late complications by treatment was: (a) no RT: 3 of 11 patients (27%); (b) remote RT: 2 of 10 patients (20%); and (c) perioperative RT: 9 of 26 patients (35%). One patient in the no-RT group lost the plate due to chronic pain. Five patients in the perioperative RT group also had plate loss, four due to osteomyelitis and/or necrosis, and one due to pain related to a recurrent tumor. No patients in the remote RT group had plate loss. The actuarial prosthesis preservation rate at 2 years was 88% for the no RT, 100% for the remote RT, and 57% for the perioperative RT groups (p = 0.05). Phantom dose measurements showed that for parallel opposed 6 MV photon beams, there was no significant increase in the dose proximal or distal to the plate in either a soft tissue- or bone-equivalent phantom. CONCLUSIONS: The impact of radiation therapy on plate preservation after mandibular reconstructive surgery using a titanium plate may be dependent on the timing of RT relative to surgery. Significantly more mandibular reconstruction plates were lost when the involved mandible received RT in the perioperative period than when RT was delivered beyond 10 months from surgery or when no RT was given. The use of alloplastic implants such as titanium plates in conjunction with myocutaneous flap coverage for mandibular reconstruction is attractive because it allows immediate reconstruction of the defect and promotes a good functional and cosmetic result; however, administration of perioperative RT may result in a higher plate failure rate.

Adolescent↗
PubMed1993

Mesalamine capsules for the treatment of active Crohn's disease: results of a 16-week trial. Pentasa Crohn's Disease Study Group.

BACKGROUND: Mesalamine is released from sulfasalazine in the colon and benefits colonic Crohn's disease. The mesalamine used in this study releases the drug throughout the small bowel and colon. Therefore, this study was designed to detect benefit for Crohn's disease involving the small bowel alone or both the colon and small bowel. METHODS: This double-blind, randomized, multicenter prospective controlled trial compared placebo and three daily doses of mesalamine in 310 patients. The primary outcome criterion was change in the Crohn's Disease Activity Index (CDAI) from baseline to final study visit. RESULTS: Patients taking 4 g/day mesalamine experienced a decrease of 72 CDAI points compared with 21 points in the placebo group (P < 0.01). Remission occurred in 43% of the 4-g group and 18% of the placebo group. Patients with ileum-only disease showed a 93-point improvement on 4 g mesalamine, compared with a 2-point improvement in similar patients on placebo. Mesalamine in this trial was not associated with clinically significant toxicity. CONCLUSIONS: This controlled-release mesalamine preparation is safe and effective at 4 g/day as a single agent in treatment of active Crohn's disease of the ileum and colon.

Adolescent↗
PubMed1992

Two doses of omeprazole versus placebo in symptomatic erosive esophagitis: the U.S. Multicenter Study.

Two hundred thirty patients with reflux symptoms and endoscopically proven erosive esophagitis were enrolled from 15 U.S. centers into a randomized, double-blind, dose-ranging study comparing placebo with omeprazole, 20 or 40 mg given once daily in the morning. Esophagitis grade 2 was present in 44% of patients, grade 3 in 37% of patients, and grade 4 in 19% of patients. Endpoints, defined as complete relief of heartburn and complete esophageal mucosal healing, were assessed after 4 and 8 weeks of treatment. Both omeprazole doses were significantly superior to placebo in complete endoscopic healing. After 8 weeks of treatment, 73.5% of patients in the 20-mg omeprazole group and 74.7% in the 40-mg omeprazole group, compared with 14.0% in the placebo group, had complete healing of the esophageal mucosa. At the end of the study, complete relief of daytime heartburn was obtained in 79.5% of patients in the 20-mg omeprazole group, 81.6% in the 40-mg omeprazole group, and 37.2% in the placebo group (P less than or equal to 0.05). Complete relief of nighttime heartburn was noted by 79.5% of patients in the 20-mg omeprazole group, 85.1% in the 40-mg omeprazole group, and 34.9% in the placebo group (P less than or equal to 0.05). The median time to complete relief of daytime and nighttime heartburn occurred earlier in the 40-mg group than in the 20-mg group (9 vs. 17 days and 9 vs. 20 days, respectively); however, these differences were not statistically significant. Relief of acid regurgitation and dysphagia also occurred earlier in the 40-mg group. Omeprazole was well tolerated in this group of patients. No unexpected adverse experiences occurred. The results of this study confirm those of six multicenter, international trials in which omeprazole in doses of 20-60 mg provided a degree of esophageal mucosal healing and complete relief of reflux symptoms superior to any other medical treatment.

Adult↗
PubMed1992

The effect of chronic fluoride administration on rat condylar cartilage.

Morphometrical and histochemical techniques were used to demonstrate changes to the cartilage layer of the rat temporomandibular joint condyle following chronic exposure to fluoride. An increase in thickness of the cartilage layer was noted in rats given 100 parts per million sodium fluoride in drinking water. No significant changes were observed with either control or low dose (10 parts per million) groups. The observed thickening was attributable to an increase in number and size of cells of the lower hypertrophic zone. Accumulations of glycogen were observed in these cells, which reflects the inhibitory effect of fluoride on glycolysis. Stimulation of chondrocytes by fluoride may have delayed the normal processes of capillary invasion, resulting in thickening of the cartilage layer. No changes to staining patterns of immature or mature types of collagen were observed, nor did the staining pattern of detectable glycosaminoglycans change due to fluoride.

Animals↗
PubMed1992

Esophageal function and gastroesophageal reflux during sleep and waking in patients with chronic obstructive pulmonary disease.

This study was conducted to assess esophageal function and pulmonary resistance changes with esophageal acidification in patients with COPD. Twelve patients with COPD and a mean age of 55.6 years were studied. Each patient underwent standard esophageal manometry, 24-h ambulatory pH testing, esophageal acid clearance evaluation during sleep, and an assessment of pulmonary resistance with and without esophageal acid perfusion. Neither airway resistance nor conductance was altered by the esophageal acid infusion; LES pressures were normal and esophageal contractile pressures were mildly decreased. Acid exposure in the upright and supine positions was within normal limits. Acid clearance during sleep was similar to that in normal subjects; however, acid clearance during waking appeared to be somewhat prolonged in the COPD patients. We conclude that patients with COPD do not have a bronchoconstrictive reflex to distal esophageal acidification, and esophageal function in these patients appears to be relatively normal.

Adult↗
PubMed1992

Patients with symptomatic ischemia have larger thallium perfusion abnormalities and more adverse prognosis than patients with silent ischemia.

OBJECTIVE: To evaluate the mechanism for silent ischemia and the effect on prognosis. DESIGN: To test the hypothesis that patients with silent (compared with symptomatic) ischemia have less severe ischemia and a more favorable prognosis, the authors prospectively evaluated 152 consecutive patients with a positive exercise electrocardiogram with exercise thallium scintigraphy and followed them for two years. SETTING: Tertiary care university-based hospital. RESULTS: Asymptomatic patients during the exercise test had a greater exercise duration (9.4 +/- 3.1 versus 6.3 +/- 2.5 mins, P < 0.01), maximal heart rate (155 +/- 20 versus 136 +/- 20 beats/min, P < 0.01), systolic blood pressure (184 +/- 21 versus 176 +/- 23 mmHg, P < 0.05) and double product than patients who were symptomatic with chest pain. Although there was no difference in the magnitude of ST depression, time to ST depression was greater in the asymptomatic (5.6 +/- 2.7 mins), compared with symptomatic (4.6 +/- 2.6 mins), group (P < 0.01). Thallium ischemic score was smaller during asymptomatic ischemia (2.1 +/- 2.7) compared with symptomatic ischemia (3.9 +/- 3.1, P < 0.01). These findings were also demonstrated in a subgroup of 107 patients with both a positive exercise electrocardiogram and positive thallium scan. The patients with asymptomatic ischemia had a two-year cardiac event rate of 5.1% compared with 13.8% in the symptomatic patients (P = 0.065). CONCLUSIONS: Patients with asymptomatic ischemia have less severe myocardial ischemia and a better prognosis than patients with symptomatic myocardial ischemia during exercise testing.

Angina Pectoris↗
PubMed1991

Experience with omeprazole in erosive oesophagitis.

Omeprazole is a potent, highly specific, and clinically efficacious anti-secretory agent. Current clinical data suggest that omeprazole could be a useful drug in the short-term treatment of patients with severe erosive oesophagitis resistant to standard H2-receptor antagonist therapy. The magnitude of omeprazole's eventual role in the treatment of acid secretory-related disorders will depend on the results of its expanded postmarketing clinical experience and upon resolution of concerns regarding potential adverse effects associated with long-term administration.

Esophagitis, Peptic↗
PubMed1991

The effect of esophageal acid volume on arousals from sleep and acid clearance.

To assess the effect of different volumes of acid infused into the esophagus, seven normal volunteers were studied in the waking and sleep state. All subjects were studied for three nights in the sleep laboratory, which included complete polysomnographic monitoring and esophageal pH recording. Multiple infusions of either 5, 15, or 25 ml of 0.1 N HCL were administered each night. Similar infusions were also accomplished in the waking state. The results showed a significant (p less than 0.05) decrease in the arousal from sleep with 25-ml vs 5-ml infusions. During sleep, the latency to the first swallow was significantly (p less than .05) shorter with the 25-ml infusion when compared with that of the 5-ml infusion. While awake, the infusion volume did not affect the latency to the first swallow. The acid clearance times were not significantly altered by the different volumes infused. It is concluded that the larger volumes of acid in the esophagus create an afferent "warning" signal to the central nervous system to produce a rapid arousal from sleep along with a shortened interval to the first swallow. These responses rapidly empty the larger acid volumes from the esophagus.

Arousal↗
PubMed1990

Effect of enprostil on the gastroduodenal mucosa of healthy volunteers.

Enprostil is a synthetic dehydro-prostaglandin E2 with gastroduodenal ulcer-healing and mucosal-protective properties. One hundred and three healthy volunteers were randomized to receive capsules of enprostil 35 micrograms b.d. (the clinically recommended dose), enprostil 70 micrograms b.d., or placebo b.d. All underwent endoscopic assessment of the gastroduodenal mucosa, scored using a 0-4 scale, at baseline and on Days 3, 7, 14, 21 and 28 of dosing. Mean and median maximum scores demonstrated a dose response, and the mean maximum scores were statistically significantly higher for both enprostil groups on each endoscopy day when compared with placebo. The majority of enprostil-treated subjects had petechial haemorrhages. The proportion of volunteers with small white-based mucosal breaks (erosions) was significantly higher for the fundus in the enprostil 70-microgram group on Days 21 and 28 when compared with placebo, but there were no significant differences between treatment groups for any area on the other study days. The 70-microgram dose was associated with significantly more gastrointestinal adverse events than the 35-microgram dose, which was similar to placebo. There were no significant differences between groups for large white-based mucosal breaks (ulcers). We conclude that oral enprostil produced gastric mucosal petechial haemorrhages, primarily in the fundus of the stomach. Gastric mucosal petechial haemorrhages are probably without clinical significance because they are very common in the general population (10-15%) and do not progress to erosions and ulcers.

Double-Blind Method↗
PubMed1990

Gastroesophageal reflux: clinical diagnosis, current therapy, future trends.

In the usual clinical setting, symptomatic gastroesophageal reflux can be equated with heartburn; however, the diagnosis of gastroesophageal reflux disease (GERD) can be obscure. Recent improvements in the quality of fiberoptic endoscopy along with other imaging and diagnostic techniques have permitted a more complete understanding of the pathophysiology of gastroesophageal reflux. The continued development of antisecretory, prokinetic, and mucosal protective agents allows the gastroenterologist a choice of effective therapeutic approaches to deal with contributing factors such as gastric acid secretion, lower esophageal sphincter pressure, or gastric motility. Although standard doses of potent H2-receptor antagonists are the focus of current reflux disease therapy, increasingly aggressive regimens will probably become available for refractory patients.

Antacids↗
PubMed1990

Healing or amelioration of esophagitis does not result in increased lower esophageal sphincter or esophageal contractile pressure.

There is conflicting evidence regarding whether lower esophageal sphincter and esophageal contractile pressures are affected by changes in the severity of gastroesophageal reflux disease. We compared the manometric and endoscopic findings from 30 patients before and after treatment for esophagitis. Before treatment, the grade of esophagitis (I-III) was significantly correlated (r = -0.37; p less than 0.05) with lower esophageal sphincter pressure, but not with esophageal contractile pressure. After treatment, the grade of esophagitis did not change or became worse in 15 patients, and became better in 15 patients. Of these, seven healed. The group that showed no endoscopic improvement demonstrated no change in lower esophageal sphincter or esophageal contractile pressures. The group that did show endoscopic improvement also demonstrated no increase in lower esophageal sphincter or esophageal contractile pressures, and this was particularly evident in those whose esophagitis healed. These data suggest that healing of esophagitis does not result in improvement of esophageal motor function.

Adult↗