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Biomedical subjects

T M Johnson

Publications and source records attributed to T M Johnson.

176 records · Page 10Linked to original sources
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Treatment of head and neck melanoma, lentigo maligna subtype: a practical surgical technique.

Melanoma with the lentigo maligna histological pattern often provides a significant and difficult challenge to the head and neck surgeon. The lentigo maligna subtype is the most common type of melanoma on the head and neck. This potentially lethal form of cancer is associated with greater nonvisual lesional extension that is often not clinically apparent. Failure to excise the entire lesion results in a higher risk of local recurrence and a poorer prognosis. The staged excision technique described herein results in histological interpretation of 100% of the peripheral margins using formalin-fixed vertical sections. Definitive local excision and soft tissue reconstruction are performed in a subsequent stage, with an assurance that 100% of the peripheral margins have been evaluated and interpreted as free of disease.

Female↗
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Surgical therapy of primary cutaneous melanoma.

This review focuses on the surgical treatment of primary cutaneous melanoma. Interpretation of biopsy results and a rational approach to preoperative screening methods for metastases are examined. The marked changes in operative approach to melanoma over the past century are reviewed, with emphasis on the impact of prospective, randomized trials upon the width of surgical margins for melanoma. General principles of current surgical technique are discussed, with attention given to modifications of technique dictated by unique anatomic tumor sites.

Biopsy↗
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Computed tomography in staging of patients with melanoma metastatic to the regional nodes.

BACKGROUND: This study addresses the yield and clinical impact of computed tomography (CT) imaging in otherwise asymptomatic patients with stage III melanoma metastatic to the regional nodes. METHODS: The database from the University of Michigan Mutlidisciplinary Melanoma Clinic was reviewed and identified 127 asymptomatic patients with stage III melanoma (regional nodal disease) who received CT scans of the head, chest, abdomen, and/or pelvis. Scans were confirmed as true positive, false positive, and normal. RESULTS: Four hundred twenty-six head and body CT scans were performed at the time of presentation of stage III disease. Twenty patients had a true-positive CT scan revealing unsuspected metastases. Fifteen patients had abnormal CT scans subsequently shown to be a benign process or second malignancy. The incidence of true-positive CT scans was not different between the groups of patients who had clinically apparent versus occult nodal disease. There was a significantly higher incidence of abdominal and pelvic metastatic sites identified by CT scan in patients with inguinal nodal disease compared with axillary or head and neck node-positive patients. CONCLUSIONS: The yield of detection of unsuspected metastases by CT scans in asymptomatic patients with stage III melanoma was not insignificant. Because patients with resected stage III disease are recommended to have adjuvant interferon-alpha for 1 year, CT staging plays an important role in identifying appropriate candidates for treatment. The toxicity of interferon-alpha therapy is not insignificant. The value of routine CT in asymptomatic patients with nodal metastasis deserves further prospective study.

Adolescent↗
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Effects of commonly used cardioactive drugs on atrial and sinoatrial conduction in man.

Atrial and sinoatrial conduction intervals were measured in patients before and after the intravenous administration of one of four cardioactive drugs: procainamide, atropine, ouabain, and propranolol. Procainamide uniformly prolonged atrial conduction and shortened sinoatrial conduction. Atropine also shortened sinoatrial conduction but did not significantly alter atrial conduction. Ouabain prolonged sinoatrial conduction in patients with normal control sinoatrial conduction intervals and did not affect atrial conduction. Propranolol did not significantly alter sinoartrial conduction and only prolonged interatrial conduction in patients with normal base line atrial conduction intervals. Of the cardioactive drugs tested, only procainamide and propranolol significantly altered the atrial conduction intervals; furthermore, the effects of these cardioactive drugs on sinoatrial conduction were disparate from their effects on atrial conduction.

Adult↗
PubMedDate not supplied

Production and characterization of monoclonal antibodies against a highly immunogenic fraction of Entamoeba histolytica (NIH:200) and their application in the detection of current amoebic infection.

Six monoclonal antibodies (MAbs) were produced against a highly immunogenic fraction derived by the chromatographic separation of the soluble preparation of axenic Entamoeba histolytica (strain NIH:200) trophozoites. Isotype characterization of the six MAbs revealed that four belonged to the IgM class and one each to the IgG1 and the IgG2a subclasses. The immunoreactivity patterns and the specificity of the MAbs with homologous and heterologous antigens were analyzed by the enzyme-linked immunotransfer blot technique and by the enzyme-linked immunosorbent assay. The MAbs reacted intensely with isolates of E. histolytica (strain NIH:200 as well as a local isolate MX1) but showed no reactivity with Entamoeba coli, Iodamoeba butschlii, Endolimax nana, Entamoeba hartmanni, free-living amoeba (Acanthamoeba harticolus) and other enteric parasites. Using the IgG1 MAb as a detecting antibody, a polyclonal-monoclonal antibody-based enzyme-linked immunosorbent assay was developed for the detection of E. histolytica antigens in stool samples of infected patients. The detection limit of the assay was 8 ng of amoebic antigen. This test was found to be specific and sensitive and yielded 100% positive results in cases with amoebiasis but did not react with controls included in the evaluation. The MAb-based enzyme-linked immunosorbent assay developed in this study will be an important test for the diagnosis of E. histolytica in the feces of infected humans; however, the limitation of the test is the inability to discriminate the pathogenic status of the amoeba detected in the stool.

Animals↗
PubMedDate not supplied

Managing patients.

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Family Practice↗
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Vomiting as a manifestation of borderline personality disorder in primary care.

BACKGROUND: Patients with borderline personality disorder often are found and treated in psychiatric settings following episodes of self-mutilation, such as wrist-slashing. Family physicians care for many patients with borderline personality disorder, but in primary care settings wrist-slashing or other physical mutilation is a less common presenting problem. Frequently these patients complain of such symptoms as nausea and vomiting that do not so obviously suggest psychopathology. METHODS: Three primary care patients with borderline personality disorder in whom episodic vomiting was the chief complaint are presented. Hypotheses from the literature about the neurobiology of vomiting and self-mutilation are discussed. RESULTS: Vomiting is a primary care analogue of self-mutilation in some patients with borderline personality disorder. CONCLUSIONS: Family physicians should include careful history taking to corroborate other features of borderline personality disorder in evaluating patients with persistent, episodic vomiting. Obtaining a history of early sexual abuse or chronic interpersonal problems as an adult should not only mitigate the compulsion for extensive, costly, and invasive gastrointestinal system evaluations in such patients, but also suggest more effective treatment strategies.

Adult↗