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Biomedical subjects

T Beckerman

Publications and source records attributed to T Beckerman.

12 recordsLinked to original sources
PubMed1993

Malignant melanoma in xeroderma pigmentosum: search for a precursor lesion.

BACKGROUND: Malignant melanomas occur with increased frequency and at an early age in patients with xeroderma pigmentosum (XP). OBJECTIVE: The purpose of this study was to describe the histologic features of malignant melanomas in patients with XP and to search for a possible precursor lesion. METHODS: Clinical records and hematoxylin-eosin-stained sections of 19 malignant melanomas from seven patients with XP were examined. A search was conducted for malignant melanoma precursor lesions (melanocytic nevi and solar lentigines lateral to and contiguous with the malignant melanomas). Basal cell carcinomas removed from the same patients were used as controls. RESULTS: Malignant melanomas were characteristically found in biopsy specimens of small elevations and/or changed color foci arising in large, flat, darkly pigmented, gradually enlarging macules. Histologically, solar lentigo was lateral to and contiguous with malignant melanoma in 88% of the malignant melanomas. Transitional areas were present. A significantly lower number (22%) of contiguous solar lentigines, without transitional areas, were observed in the basal cell carcinoma controls. Most of the invasive malignant melanomas were spindle cell malignant melanomas. CONCLUSION: We propose that solar lentigo is the most common precursor lesion of malignant melanoma in patients with XP.

Adolescent↗
PubMed1992

Experimentally induced infection by oral anaerobic microorganisms in a mouse model.

A mouse model was developed to study the abscessogenic potential of pure and mixed cultures of oral anaerobes associated with infections of endodontic origin. Maximum subcutaneous lesions were seen on their backs between 3 and 14 d after inoculation. Strains of Fusobacterium nucleatum, Peptostreptococcus anaerobius, and Veillonella parvula were pathogenic in pure culture. A mixed culture of F. nucleatum with either Porphyromonas gingivalis or Prevotella intermedia was significantly more pathogenic than F. nucleatum in pure culture. Histopathological examination of tissue sections from control mice injected with India ink in the medium demonstrated a pathway of particulate migration from the backs of the mice to their abdomen.

Abdomen↗
PubMed1991

Evidence for involvement of tyrosine in estradiol binding by rat uterus estrogen receptor.

The possibility of tyrosine involvement in steroid binding by rat uterus estrogen receptor (rER) was investigated. Chemical modification of rER with reagents such as tetranitromethane (TNM) and N-acetylimidazole (NAcI) inhibited estradiol binding. Steroid binding was inhibited to a greater extent at pH 8 than at pH 6, indicating the participation of tyrosine (TNM has increasing affinity for cysteine ove tyrosine at pH 6). Inhibition patterns remained similar for incubations at 0-4 degrees C or 37 degrees C. NAcI inhibited rER steroid binding at 37 degrees C, but not at 0-4 degrees C. Hydroxylamine incubated in the presence of rER and NAcI appeared to reverse this inhibition. Thus, these findings indicate that the phenyl ring and possibly the phenolic hydroxyl of tyrosine are involved in steroid binding of the receptor.

Animals↗
PubMed1984

Central mucoepidermoid carcinoma. Review of the literature and report of a case associated with an apical periodontal cyst.

Mucoepidermoid carcinoma arising centrally within the jaws is a rare lesion which exhibits considerable histologic variability and an unpredictable clinical course. Its specific pathogenesis is unknown, although speculation has centered on the pluripotential capabilities of the epithelial lining of odontogenic cysts. The case presented here illustrates the relationship of such a lesion arising from the cyst wall of an apical periodontal cyst.

Adult↗
PubMed1983

Distribution of specific binding of [3H]promegestone in benign prostatic hypertrophy in regard to age, race and histological differences.

Progesterone receptors were measured in BPH tissues obtained via open prostatectomy on over thirty [30] patients. Specific receptor concentration was determined by computation of the suppressible binding from the 8S region of the glycerol density gradient (centrifuged in a vertical rotor) as described by McGuire and his colleagues. Measurable progesterone receptor concentrations were obtained from all thirty specimens. These patients were subsequently categorized on the basis of several parameters including age, race, and histology of the hyperplasia. Age and race groupings demonstrated no specific distribution pattern, however, there was a marked difference in mean receptor concentration between the histological classifications.

Aged↗