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Biomedical subjects

W C Lambert

Publications and source records attributed to W C Lambert.

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

Electroporation of normal human DNA endonucleases into xeroderma pigmentosum cells corrects their DNA repair defect.

Cells from patients with the cancer-prone inherited disease, xeroderma pigmentosum (XP) are known to be defective in the endonuclease-mediated incision step in excision repair of a number of different types of DNA adducts, but the molecular events responsible have not been delineated. We have previously reported isolation of two DNA endonucleases, pI 4.6 and 7.6, from normal human chromatin which recognize adducts produced by psoralen plus long wavelength ultraviolet radiation (UVA). These endonucleases are both present in XP complementation group A (XPA) cells even though these cells are hypersensitive to this type of damage. We now report that introduction by electroporation of either normal endonuclease into XPA cells restored their markedly deficient DNA repair-related unscheduled DNA synthesis (UDS) to higher than normal levels following exposure to psoralen plus UVA. Introduction of XPA endonucleases into similarly treated XPA cells had little or no restorative effect on UDS. However, both normal and XPA endonucleases increased UDS in normal cells to higher than normal levels. These results indicate that XPA cells have endonucleases which can repair these adducts but which cannot function in intact cells unless a factor(s), which they lack is provided by normal cells.

DNA Repair↗
PubMed1990

Histoid lepromas of lepromatous leprosy.

Histoid lepromas are a rare eruption in patients with lepromatous leprosy. A 59-year-old man from India with lepromatous leprosy who developed histoid lepromas and who was dapsone resistant was studied. These tumors resembled cutaneous metastases. This Indian man is to our knowledge the first patient to be reported with this rare disorder in the continental United States.

Dapsone↗
PubMed1990

Dermatopathia pigmentosa reticularis.

Dermatopathia pigmentosa reticularis is a rare disorder that presents as reticulate pigmentation distributed widely all over the cutaneous surface. Only nine patients with this disease have been described previously. Our patient had no fingernail and toenail prints, a striking finding also noted in some, but not all, of the other nine patients. Our patient also had a history of a seizure disorder and had two cutaneous neurofibromas, unlike the other patients with this disorder. However, there were no other findings, such as Lisch nodules of the iris, to suggest a diagnosis of von Recklinghausen's disease.

Adult↗
PubMed1990

Nuclear morphometry as a prognostic indicator in colorectal carcinoma resected for cure.

The prognostic value of nuclear morphometry in addition to clinical and pathologic features was retrospectively studied in 64 cases of colorectal carcinoma resected for cure with a minimum of five years of follow-up. By univariate analysis, patient outcome was found to correlate with the presence of serosal involvement (P = .003), the presence of lymph node involvement (P = .01), the number of involved lymph nodes (P = .0001) and the mean nuclear area (P = .02). With multivariate analysis, only the number of involved lymph nodes significantly correlated with the survival (P = .0001). In a subsequent multivariate model expressing lymph node status as the presence or absence of metastasis, the presence or absence of serosal involvement and the mean nuclear area were both found to independently correlate with the outcome (P = .003 and P = .02, respectively). Linear regression analysis revealed significant colinearity between the mean nuclear area and the number of involved lymph nodes (P = .03). Accelerated failure time models based on determination of serosal involvement and then either specification of the number of involved lymph nodes or calculation of the mean nuclear area were of comparable predictive value to the determination of the number of involved lymph nodes alone. The former appeared to be better at identifying a subgroup of patients with good prognosis. This study demonstrates that two or more models based on pathologic features may be of comparable predictive value in colorectal carcinoma resected for cure, including models that incorporate mean nuclear area.

Adenocarcinoma↗
PubMed1990

Adult linear IgA bullous dermatosis: a polymorphic disorder.

We report on two patients with unusual forms of adult linear IgA bullous dermatosis. One was a middle-aged woman who had targetoid lesions and bullae on her trunk and extremities. This patient first presented with lesions that clinically resembled erythema multiforme, but these evolved into a widespread eruption with bulging, elongated bullae. Examination of a biopsy specimen showed changes compatible with dermatitis herpetiformis and bullous pemphigoid. Findings on immunofluorescence studies showed deposition of linear IgA at the basement membrane zone. The second patient was an elderly woman with intensely pruritic vesicles whom we classified as having vesicular pemphigoid, until the linear IgA band on direct immunofluorescent test results became the predominant immunofluorescent finding. These cases are reported because of their unusual clinical presentations. The mechanism for the targetoid lesions in the first patient is discussed.

Aged↗
PubMed1989

Prognostic value of morphometry in papillary thyroid carcinoma.

The value of morphometric analysis in addition to standard prognostic indicators was studied in 28 cases of papillary thyroid carcinoma. Standard features included age, sex, lymph node status, tumor size, and encapsulation. The mean follow-up was 47 months (maximum, 140 months). Recurrences were documented in six patients at a mean time of 34 months; five patients recurred with distal metastases and one patient recurred with local disease. Univariate analysis most closely associated tumor recurrence with nuclear anisotropism (the standard deviation of the estimated nuclear area [ENASD]) and tumor size. With forward stepwise incremental analysis, the value of tumor size was lost and only the ENASD and the cellularity mean index (CMI), defined as the percentage of tumor volume composed of tumor cells, significantly correlated with recurrence. Fifty-five percent of patients with an ENASD greater than 17 microns2 and a CMI greater than 40% developed recurrence as compared with 5% of patients with lesser values (P = .0001). Morphometric analysis may significantly contribute to the role of histopathology in the evaluation of papillary thyroid carcinoma and may also provide information regarding prognosis not obtained by standard methods.

Adult↗
PubMed1989

How to write and take objective, multiple choice examinations. Quantitative analysis of the scientific data base.

Although there are numerous ways in which physicians evaluate one another and themselves, the multiple choice examination has become the key method for evaluating the scientific data base of both medical students and postgraduate physicians. Knowledge of the mechanisms at work in such examinations is thus important for both giving and taking these examinations. Analysis of these mechanisms is now provided.

Educational Measurement↗
PubMed1989

Treatment of multiple apocrine hidrocystomas with the carbon dioxide (CO2) laser.

The apocrine hidrocystoma tends to occur as a solitary facial cystic lesion. We report an unusual patient in whom there were multiple apocrine hidrocystomas scattered over the periorbital region and ears. Although solitary apocrine hidrocystomas are easily treated with excision, we had good results employing carbon dioxide laser vaporization in the treatment of numerous hidrocystomas.

Apocrine Glands↗
PubMed1989

The Muir-Torre syndrome: a disease of sebaceous and colonic neoplasms.

The Muir-Torre syndrome of sebaceous neoplasms of the skin, with or without keratoacanthomas, and multiple low-grade visceral malignancies with prolonged survival is a rare disorder. Colonic polyps are frequently present, and the syndrome appears to be familial. We report 2 unrelated patients with the Muir-Torre syndrome. Each case exhibited sebaceous adenomas. Gastrointestinal findings included colonic adenocarcinomas and a tubulovillous adenoma. Although an unusual disease, the Muir-Torre syndrome requires recognition because these patients are at risk for multiple primary malignancies and may have family members also at risk.

Adenocarcinoma↗
PubMed1989

Xeroderma pigmentosum.

Xeroderma pigmentosum is a rare, recessively inherited, sun-sensitive disorder with a defective DNA repair mechanism that is the best model currently available linking human cancer to exposure to a specific carcinogen. Laboratory and epidemiological studies of this disease are providing extensive insight into the etiology of cancer in the general population.

DNA Repair↗
PubMed1988

Beyond hybridomas. Cell identification by in situ nucleic acid hybridization.

Nucleic acid hybridization is a powerful technique that has been developed almost entirely by molecular biologists. It has the potential to identify specific types of cells with far greater sensitivity and specificity than such current methods as polyclonal or monoclonal antibodies or lectins. As the RNAs or DNAs (probes) needed for this technique become available, it is likely to replace other methods of identifying many kinds of cells in tissue sections.

Antibodies, Monoclonal↗
PubMed1988

Multiple connective tissue nevi.

Connective tissue nevi are uncommon, and rarely suspected clinically because of their diverse morphologic presentations. Histologically, we define connective tissue nevi as discrete areas within the papillary or recticular dermis where a clear predominance or depletion of collagen, elastin, or glycosaminoglycans may be found. We report a case of multiple connective tissue nevi with a predominance of dermal collagen deposition, without extracutaneous findings and no family history of connective tissue nevi. These lesions can thus be classified as being of the eruptive collagenoma type.

Adult↗