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Biomedical subjects

J Crowe

Publications and source records attributed to J Crowe.

At least 73 records · Page 4Linked to original sources
PubMed1990

Biopsy of the breast for mammographically detected lesions.

We prospectively studied 718 women who underwent biopsy of the breast for suspicious, mammographically detected mammary lesions in an attempt to identify key clinical risk factors, as well as roentgenographic characteristics associated with the appearance of early carcinoma of the breast. Patients with a benign outcome had an average age of 55 years versus 63 years for patients with carcinoma of the breast. Seventy-six per cent of these patients had no previous history of mammary problems, 20 per cent had a positive family history for carcinoma of the breast, 58 per cent were premenopausal and 21 per cent had used birth control pills. Except for age (p less than 0.001), the distribution of clinical risk factors was equal among patients with benign or malignant outcomes. Suspicious mammographic findings included mass lesions (53 per cent), calcifications (36 per cent) and the association of both (11 per cent). The predominant Wolfe pattern on mammography was P1 (36 per cent). No relationship was observed between Wolfe pattern and malignant conditions. In this group of patients, mammography was poorly specific; however, the positive predictive value increased with age and is related to the age-specific prevalence of carcinoma of the breast. Eight hundred and twenty-five lesions were removed. Twenty-five per cent (n = 203) of the specimens taken at biopsy contained carcinoma. Stellate mass lesions were highly suggestive of a malignant growth (p less than 0.0001). No relationship between the size of the suspicious mammographic mass and the malignant lesion was observed. A marked correlation (chi-square test with Yate's correction) was observed between malignant tumor and lesions with a linear or branching pattern, more than 15 calcifications, or small sized calcifications. The presence of a mass with calcifications was associated with carcinoma in 34 per cent. The incidence of invasive carcinoma was much higher for mass lesions (81 per cent) than for suspicious calcifications (56 per cent) (p less than 0.0001).

Adult↗
PubMed1989

Regulation of the hepatic transferrin receptor in hereditary hemochromatosis.

The liver is the main site of iron accumulation and pathologic sequelae in hereditary hemochromatosis. Whether this is a result solely of inappropriately increased absorption of iron by the gastrointestinal tract or a more generalized regulatory failure of iron balance is unknown. Using immunohistochemical techniques, we have examined the effects of therapeutic changes in liver iron stores on the expression of the hepatic transferrin receptor in hereditary hemochromatosis. Ten patients with untreated hereditary hemochromatosis had no detectable staining for transferrin receptor in their liver biopsies. All had increased hepatic ferritin (mean = 19.9 micrograms per mg protein, range = 1 to 31.7 micrograms per mg protein) and hepatic iron levels (mean = 36.2 micrograms per mg protein, range = 3.6 to 69.9 micrograms per mg protein). In contrast, hepatocyte transferrin receptor was detected in seven patients in whom hepatic iron stores were markedly depleted by venesection (hepatic ferritin mean = 0.32 microgram per mg protein, range = 0.16 to 0.53 microgram per mg protein; hepatic iron mean = 0.98 microgram per mg protein, range = 0.3 to 2.1 micrograms per mg protein). Sequential data from one patient confirmed the reexpression of receptor in response to therapeutic iron depletion, whereas data from another patient studied during treatment illustrated a reciprocal relationship between liver tissue distribution of iron and expression of transferrin receptor. The finding that appropriate physiologic regulation of the hepatic transferrin receptor operates in hereditary hemochromatosis does not support the concept of a generalized defect in receptor-mediated uptake of transferrin-bound iron.

Antibodies, Monoclonal↗
PubMed1989

Optimizing the immunohistochemical signal from the transferrin receptor in liver tissue.

Cellular expression of the transferrin receptor is determined by the proliferative state and iron requirements of the cell. Previous immunohistochemical studies using a number of anti-(transferrin receptor) monoclonal antibodies confirmed the biochemical evidence that hepatocytes express the receptor, although the distribution shown was patchy with only a small number of cells showing positive staining. In the present study, a number of techniques have been compared to optimize detection of the immunohistochemical signal from the transferrin receptor in human liver tissue. Using an alkaline phosphatase detection system, widespread expression of this receptor with both cytoplasmic and membrane staining was found in all parenchymal and non-parenchymal cells.

Alkaline Phosphatase↗
PubMed1989

Comparison of 40 mg famotidine nightly and 150 mg ranitidine b.d.: ulcer healing and symptom relief in benign gastric ulcer.

Two hundred and eight patients with benign gastric ulcers seen on endoscopy were recruited by 13 hospitals in the United Kingdom and Ireland into this double-blind study. Patients were assigned by pre-randomized schedule to 8 weeks of treatment with either 40 mg famotidine at night or 150 mg ranitidine b.d. Repeat endoscopy confirmed complete ulcer healing in 62 of 77 evaluable patients in the famotidine group (81%) and 58 of 71 in the ranitidine group (82%). The treatments were equally effective in promptly relieving day and night pain. Adverse events were uncommon; dizziness and headaches were the most frequently reported in both groups. In conclusion, night-time famotidine is as effective as twice daily ranitidine in healing benign gastric ulcers and provides similarly rapid symptomatic relief.

Aged↗
PubMed1989

Single night-time doses of 40 mg famotidine or 800 mg cimetidine in the treatment of duodenal ulcer.

Famotidine (40 mg) and 800 mg cimetidine as single night-time doses were compared in a randomized, double-blind, multicentre study of acute treatment for duodenal ulceration. Fifteen centres recruited 304 patients into the study. Of these, 274 were included for analysis, with 136 receiving famotidine and 138 receiving cimetidine. After 4 weeks, 75% of the patients who received famotidine and 77% of the patients who received cimetidine were healed. At 6 weeks the cumulative healing rates were 91% with famotidine and 87% with cimetidine. Differences between the groups were not significant at 4 or 6 weeks. No significant difference in healing rates between smokers and non-smokers was found. Day and night pain resolved rapidly in both groups. Both treatments were well-tolerated; adverse events were reported in 17 patients on famotidine and 18 on cimetidine, with headache the most frequent event in both groups. Famotidine is effective and well-tolerated in the short-term treatment of duodenal ulcer.

Adolescent↗
PubMed1988

In vivo and in vitro analysis of ptl1, a yeast ts mutant with a membrane-associated defect in protein translocation.

Mutants defective in the ability to translocate proteins across the membrane of the endoplasmic reticulum were selected in Trp- Saccharomyces cerevisiae on the basis of their ability to retain a fusion protein in the cytosol. The fusion comprised the prepro region of prepro-alpha-factor (MF alpha 1) N-terminal to phosphoribosyl anthranilate isomerase (TRP1). The first of the protein translocation mutations, called ptl1, results in temperature-sensitivity of growth and protein translocation. At the non-permissive temperature, precursors to several secretory proteins accumulate in the cytosol. Using this mutant, we demonstrate that the prepro-carboxypeptidase Y that had been accumulated in the cytosol at the non-permissive temperature could be post-translationally translocated into the endoplasmic reticulum when cells were returned to the permissive temperature. This result indicates that post-translational translocation of preproteins across endoplasmic reticulum membranes can occur in vivo. We have also determined that the temperature-sensitive component is membrane-associated in ptl1, and that the membranes derived from this strain show a reversible temperature-sensitive translocation phenotype in vitro.

Biological Transport, Active↗
PubMed1987

Combined anti-muscarinic and H2 receptor blockade in the healing of refractory duodenal ulcer. A double blind study.

The purpose of this study was to determine if pirenzepine and cimetidine given together was superior to cimetidine alone in inducing healing of refractory duodenal ulcers which remained unhealed after treatment with cimetidine or ranitidine for at least eight weeks. One hundred and thirty one patients from six centres were randomised to receive either cimetidine (C) 800 mg daily or cimetidine 800 mg plus pirenzepine (C + P) 100 mg daily under double blind conditions for six weeks. The healing rate was similar in both groups, irrespective of the method of calculation. On an intent-to-treat analysis, healing was: C 66%, C + P 57%, and amongst the patients who completed treatment, healing was 70% in both groups. Patients on C and on C + P experienced a similar decrease in daytime and in night time pain. Side effects of treatment, notably dry mouth and blurred vision, were reported more often by patients on combination therapy. Combined treatment with cimetidine plus pirenzepine in patients with refractory duodenal ulcer is unlikely to be beneficial.

Adult↗
PubMed1987

Esophageal function in diabetes mellitus with special reference to acid studies and relationship to peripheral neuropathy.

Esophageal function in 20 subjects with diabetes mellitus was assessed using esophageal manometry, 24-hr ambulatory esophageal pH monitoring, and esophageal scintigraphy. Seven patients had abnormal esophageal manometric studies, and this abnormality was significantly associated with peripheral neuropathy. Almost half of the subjects studied demonstrated excessive gastroesophageal acid reflux, but there was no correlation between the likelihood of abnormal reflux and the presence of peripheral neuropathy. Esophageal scintigraphy was relatively insensitive in the detection of abnormal esophageal function in diabetics.

Adult↗
PubMed1985

Radiation-induced solitary rectal ulcer.

A case of radiation-induced solitary rectal ulcer is presented. The unusual posterior location with involvement of the internal iliac artery produced massive lower intestinal hemorrhage. Temporary control was obtained with percutaneous arterial catheter embolization, but definitive control necessitated surgical resection.

Embolization, Therapeutic↗