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M H Johnston

Publications and source records attributed to M H Johnston.

7 recordsLinked to original sources
PubMed1996

The prevalence and clinical characteristics of short segments of specialized intestinal metaplasia in the distal esophagus on routine endoscopy.

OBJECTIVE: To prospectively determine the prevalence and clinical characteristics of short segments of specialized intestinal metaplasia in the distal esophagus. Short segment is defined as extending less than 2 cm proximal to the esophagogastric junction. This has been referred to by some investigators as "short segment Barrett's esophagus." METHODS: One hundred and seventy two patients undergoing elective esophagogastroduodenoscopy were consecutively enrolled. Patients with known Barrett's esophagus were excluded. All study patients completed a symptom questionnaire. At endoscopy, the presence of esophagitis and locations of the diaphragmatic hiatus, esophagogastric junction, and the squamocolumnar junction were recorded. Biopsy specimens were obtained at the squamocolumnar junction to identify specialized intestinal metaplasia and 2 cm above the squamocolumnar junction to evaluate for histological esophagitis. RESULTS: Two patients (1.2%) had at least 2 cm of columnar-lined esophagus. Of the 170 patients without 2 cm of columnar-lined esophagus, 16 (9.4%) patients had short segments of specialized intestinal metaplasia. Twelve (7.0%) of these patients had specialized intestinal metaplasia limited to the esophagogastric junction. All patients with specialized intestinal metaplasia were Caucasian, and there was a slight male predominance. Patients without specialized intestinal metaplasia (n = 154, 90.6%) did not differ statistically with respect to age, gender, use of acid-suppressing drugs, alcohol, or smoking history. Pyrosis and regurgitation were significantly more common in patients with specialized intestinal metaplasia involving the distal 2 cm of the esophagus or the esophagogastric junction. Cough was more common in the group with specialized intestinal metaplasia limited to the esophagogastric junction. The groups were similar in frequency of dysphagia, globus sensation, nocturnal pyrosis, eructation, early satiety, nausea, and abdominal pain. CONCLUSIONS: Specialized intestinal metaplasia less than 2 cm proximal to the esophagogastric junction is common in Caucasian patients undergoing routine esophagogastroduodenoscopy. Pyrosis and regurgitation are significantly more common in patients with short segments of specialized intestinal metaplasia, whether involving the distal 2 cm of the esophagus or the esophagogastric junction alone. Alcohol and tobacco use are no more common in patients with specialized intestinal metaplasia than in those without metaplasia. The presence of specialized intestinal metaplasia did not correlate with either endoscopic or histological esophagitis.

Age Distribution↗
PubMed1995

Expansion of the Ki-67 proliferative compartment correlates with degree of dysplasia in Barrett's esophagus.

BACKGROUND: Barrett's esophagus is a histologically defined premalignant lesion of the esophagus in which normal squamous epithelium is replaced by intestinalized columnar epithelium. In a multistep progression from Barrett's esophagus to fully developed carcinoma, accelerated proliferation may indicate or precede genomic instability and, therefore, may be an important factor in the pathogenesis and/or prediction of malignant transformation. Ki-67 is a nuclear antigen expressed in proliferating cells, (G1, S, G2, and M phases) but not in resting cells (G0 phase). This study was undertaken to determine if Ki-67 expression correlates with the degree of dysplasia and if Ki-67 expression can help to differentiate those patients with or without dysplasia. METHODS: The Ki-67 proliferation fraction in 87 paraffin embedded esophageal biopsies from 43 patients with the Ki-67 antibody (MIB-1) was analyzed using immunohistochemistry. Using a computerized proliferation index program (QNA v2.54, Becton Dickinson Cellular Imaging Systems, Inc., Elmhurst, IL), a Ki-67 score was derived for the luminal surface, upper esophageal crypt, lower crypt, and underlying glandular zone of the columnar-lined esophagus. RESULTS: Significant differences in Ki-67 scores were noted in each zone among different histologic categories: normal gastric ([NG] n = 17); Barrett's without dysplasia ([ND] n = 17); low grade dysplasia ([LG] n = 21); high grade dysplasia ([HG] n = 14); and adenocarcinoma ([CA] n = 5). The pattern of Ki-67 expression was associated strongly with each histologic category. The percentage of Ki-67 positive nuclei in each mucosal zone statistically separated high grade from low grade dysplasia (P < 0.001). In high grade dysplastic tissues, the Ki-67 positive nuclei were found predominantly on the surface epithelium and upper crypt zones, whereas in low grade dysplasia, the majority of Ki-67 positive nuclei were found in the lower crypt zone. The number of Ki-67 positive nuclei in each mucosal component also was significantly different in Barrett's esophagus without dysplasia when compared with Barrett's esophagus with low grade dysplastic tissues. (P < 0.001) Staining patterns of indefinite for dysplasia by H & E staining separated into several distinct patterns (five LG, seven ND, one NG) whereas six biopsies with low grade dysplasia had a Ki-67 expression pattern more consistent with that of high grade dysplasia. CONCLUSION: The Ki-67 staining pattern correlated with histologic findings in Barrett's esophagus and may represent an additional parameter for differentiating patients with or without dysplasia.

Adult↗
PubMed1982

Dietary management of obesity: evaluation of the time-energy displacement diet in terms of its efficacy and nutritional adequacy for long-term weight control.

1. An unsupplemented 4200 kJ (1000 kcal) diet emphasizing large quantities of relatively unrefined complex carbohydrates was evaluated among sixty obese adults for its effectiveness and nutritional adequacy in a long-term weight-control programme. Patients were followed individually as outpatients by a physician and dietician-an average of thirteen visits over 26 weeks. Assessment of health indices included anthropometric measurements, blood pressure, lipid levels and assays for seven vitamins, beta-carotene and iron. 2. Weight loss averaged 8.2 kg or 24% of excess weight during the 6 months of active treatment. Over an average of 17 months of post-treatment follow-up, 44% of patients continued to lose weight and 92% remained below pretreatment levels. 3. Average skinfold thickness fell 7 mm (P less than 0.001) whereas muscle mass was maintained (arm muscle circumference + 10 mm, not significant; creatinine-height index + 3% of standard (Bistrian et al. 1975; not significant). Systolic and diastolic blood pressure fell 7 and 5 mmHg respectively (P less than 0.01). Total serum cholesterol and triglycerides fell 200 and 660 mg/1 respectively (P less than 0.01), while high-density-lipoprotein-cholesterol remained statistically unchanged. Mean serum levels of retinol, beta-carotene, folate, vitamin B12, ascorbic acid, Fe and transferrin saturation, and activity coefficients for thiamin, riboflavin and pyridoxine were within normal limits after periods of treatment ranging from 5 to 84 weeks. 4. An earlier age of onset of obesity tended to be associated with greater weight loss during treatment and lesser weight rebound during follow-up. 5. The results indicate that the experimental diet, without supplementation, was nutritionally adequate as well as effective for long-term weight control.

Adult↗
PubMed1980

Acclimation, temperature selection, and heat exchange in the turtle, Chrysemys scripta.

Turtles acclimated to temperatures between 3 and 19 degrees C were placed in a thermal gradient. The animals usually selected temperatures above 28 degrees C within 1 h after placement in the gradient, attaining a final thermal preferendum between 31 and 33 degrees C. Turtles placed in the gradient for extended periods of time were more active during the day; the temperature selected was not related to activity or time of day. Turtles were transferred from a constant temperature bath at 10 or 30 degrees C to a calorimeter at 30 or 10 degrees C. Mean body temperature (Tb) and temperatures of the heart (The), brain (Tbr), and cloaca (Tcl) as well as heart rate were continuously monitored. In a 0.76-kg turtle, temperatures increased to two-thirds of the final difference between the initial temperature and the final temperature in the following times (min): Tb, 5.5; The, 6.0; Tcl, 9.0. The increase in Tbr varied depending on whether the head was extended or retracted. Rapid changes in ambient water temperature had relatively little effect on the heart rate of a submerged turtle. Heart rates were closely related to The and were practically independent of brain temperature.

Acclimatization↗