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Biomedical subjects

W C Lambert

Publications and source records attributed to W C Lambert.

At least 55 records · Page 3Linked to original sources
PubMed1994

Orthosorb resorption evaluation using MRI and histologic analysis.

Resorbable bone fixation devices may be used in various surgical procedures for internal fixation in place of traditional metallic devices. Currently, there is no radiographic technique for tracing the postsurgical location and resorption of these devices. This study was undertaken to ascertain whether magnetic resonance imaging is a suitable tool for performing such evaluations. Using an animal model, the authors investigated the correlation over time between the magnetic resonance image of a surgically implanted pin and its histologically verified location and state.

Animals↗
PubMed1994

The role of sunlight and DNA repair in melanoma and nonmelanoma skin cancer. The xeroderma pigmentosum paradigm.

BACKGROUND AND DESIGN: The frequency of melanoma and nonmelanoma skin cancer is increasing rapidly in the United States. However, the linkage of these cancers to sun exposure has been questioned because of differences in anatomic site distribution. To obtain insights into the development of these skin cancers, we examined reports of 132 patients with xeroderma pigmentosum (XP), an inherited cancer-prone, DNA repair-deficient disorder with marked clinical and laboratory UV hypersensitivity. RESULTS: Malignant skin neoplasms were present in 70% of the patients with XP at a median age of 8 years, which is 50 years earlier than in the US white population. Fifty-seven percent of the patients had basal cell or squamous cell carcinoma, and 22% had melanoma. The frequency of melanomas, like the frequency of nonmelanoma skin cancers (basal cell and squamous cell carcinomas), anterior eye cancers, and tongue cancers, but unlike that of internal neoplasms, was increased 1000-fold or more in patients with XP who were younger than 20 years. As in the general population, the anatomic distribution of melanomas was different from that of nonmelanomas in the patients with XP. CONCLUSIONS: These data suggest that (1) DNA repair plays a major role in the prevention of cutaneous cancers in the general population and (2) sunlight exposure is responsible for the induction of melanoma as well as nonmelanoma skin cancer in patients with XP, although acting by different mechanisms for the two types of skin cancer.

Adolescent↗
PubMed1992

Defective DNA endonuclease activities in Fanconi's anemia cells, complementation groups A and B.

Cells from patients with the inherited disorder, Fanconi's anemia (FA), were analyzed for endonucleases which recognize DNA interstrand cross-links and monoadducts produced by psoralen plus UVA irradiation. Two chromatin-associated DNA endonuclease activities, defective in their ability to incise DNA-containing adducts produced by psoralen plus UVA light, have been identified and isolated in nuclei of FA cells. In FA complementation group A (FA-A) cells, one endonuclease activity, pI 4.6, which recognizes psoralen intercalation and interstrand cross-links, has 25% of the activity of the normal human endonuclease, pI 4.6, on 8-methoxypsoralen (8-MOP) plus UVA-damaged DNA. In FA complementation group B (FA-B) cells, a second endonuclease activity, pI 7.6, which recognizes psoralen monoadducts, has 50% and 55% of the activity, respectively, of the corresponding normal endonuclease on 8-MOP or angelicin plus UVA-damaged DNA. Kinetic analysis reveals that both the FA-A endonuclease activity, pI 4.6, and the FA-B endonuclease activity, pI 7.6, have decreased affinity for psoralen plus UVA-damaged DNA. Both the normal and FA endonucleases showed approximately a 2.5-fold increase in activity on psoralen plus UVA-damaged reconstituted nucleosomal DNA compared to damaged non-nucleosomal DNA, indicating that interaction of these FA endonucleases with nucleosomal DNA is not impaired. These deficiencies in two nuclear DNA endonuclease activities from FA-A and FA-B cells correlate with decreased levels of unscheduled DNA synthesis (UDS), in response to 8-MOP or angelicin plus UVA irradiation, in these cells in culture.

Cell Line↗
PubMed1992

Xeroderma pigmentosum endonuclease complexes show reduced activity on and affinity for psoralen cross-linked nucleosomal DNA.

Two DNA endonuclease complexes have been isolated from the chromatin of normal human and xeroderma pigmentosum, complementation group A (XPA), lymphoblastoid cells which are active on DNA damaged with psoralen plus long wavelength ultraviolet radiation (UVA). In both normal and XPA cells, one endonuclease complex, pI 4.6, recognizes the psoralen cross-link and the other endonuclease complex, pI 7.6, recognizes the psoralen monoadduct. The levels of activity of these complexes from both normal and XPA cells are similar on damaged naked DNA. Kinetic analysis of assays using graduated concentrations of substrate revealed that selective activity of these endonuclease complexes on 8-MOP plus UVA treated DNA correlates with a reduction in Km of these complexes, indicating an increased affinity for, or rate of association with, damaged naked DNA. When the damaged substrates were reconstituted into core nucleosomes (without histone H1), both normal endonuclease complexes showed a 2.5-fold enhancement of activity, which correlated kinetically with a further increase in affinity, or rate of association (decreased Km), for this damaged nucleosomal substrate. This increase in activity and in affinity was reduced but not eliminated when histone H1 was present. By contrast, neither XPA endonuclease complex showed this enhanced activity on, or affinity for, damaged core nucleosomal DNA, and actually showed decreased activity, and affinity, when histone H1 was present. Introduction, via electroporation, of either of the normal complexes into 8-MOP plus UVA treated XPA cells in culture corrected their DNA-repair defect, further confirming the role of these complexes in the repair process.

Cell Line, Transformed↗
PubMed1992

Co-recessive inheritance: a model for DNA repair and other surveillance genes in higher eukaryotes.

The co-recessive inheritance hypothesis proposes that certain recessively inherited diseases require homozygosity and/or hemizygosity for defective alleles at more than one locus simultaneously for the trait to be expressed. Although this hypothesis was originally proposed in the context of defective alleles for genes coding for DNA-repair functions, it need not be limited to this context, and genetic selection pressure may favor this model for genes involved in surveillance of any type. The co-recessive inheritance hypothesis also predicts extremely high carrier frequencies, likely affecting much of the general population, for defective alleles associated with these rare recessive diseases. The model predicts much lower rates of consanguinity between the parents of affected individuals than autosomal recessive inheritance, allowing it to be tested epidemiologically, and recent data suggest that the hypothesis may be valid for some cases of ataxia telangiectasia and xeroderma pigmentosum. The model provides possible explanations for a number of otherwise puzzling findings in several diseases associated with defective DNA repair.

Animals↗
PubMed1992

Metastasis.

Explore the source record for details and available documents.

Humans↗
PubMed1991

Detection of anti-basement membrane zone antibodies in bullous systemic lupus erythematosus.

We describe a 42-year-old black woman with long-standing systemic lupus erythematosus in whom vesiculobullous lesions developed. Routine histologic and immunologic studies fulfilled the criteria for the diagnosis of bullous systemic lupus erythematosus. Indirect immunofluorescence showed antinuclear antibodies without basement membrane zone fluorescence. We destroyed the nuclear antigens of the indirect immunofluorescence substrate with 2 mol/L sodium chloride, which unmasked basement membrane zone linear IgG staining. We also confirmed anti-basement membrane zone antibodies by employing a new technique of direct immunofluorescence on sodium chloride-split skin. Our finding prove that a thorough search for anti-basement membrane zone antibodies can be revealing. Our results support the idea that a subset of bullous systemic lupus erythematosus has the staining characteristics of epidermolysis acquisita, with the dermal side of the split skin showing linear immunoglobulin deposition.

Adult↗
PubMed1991

Florid cutaneous papillomatosis, malignant acanthosis nigricans, and pulmonary squamous cell carcinoma.

A 72-year-old man had florid cutaneous papillomatosis (FCP), which is an obligatory paraneoplastic syndrome always associated with an internal malignancy. The cancer, which is usually intraabdominal and most often gastric in origin, evolves parallel to the FCP. This patient is the first case of FCP occurring in association with a lung malignancy. An association of FCP with other signs of internal cancer is common, with malignant acanthosis nigricans usually appearing many times with the sign of Leser-Trélat. FCP, malignant acanthosis nigricans, and the sign of Leser-Trélat are part of a continuum, developing by a common or similar pathogenic pathway due to an underlying malignancy producing a factor possibly similar to human epidermal growth factor.

Acanthosis Nigricans↗
PubMed1991

The treatment of atypical lipoma with liposuction.

Large lipomas may best be treated with liposuction. Once a lipoma enlarges to 4 cm or more, liposuction has several advantages over conventional surgery. A well-demarcated lipoma 15 cm in diameter and deep to muscle was treated by liposuction. Biopsy showed an atypical lipoma. Because the entire tumor was removed by liposuction, we feel that the prognosis is excellent. The cosmesis and morbidity results were far superior to those anticipated with conventional excisional surgery. Small superficial lipomas may be treated by suction lipectomy and the surrounding area can be contoured symmetrically at the same time, whereas large ones can be liposuctioned completely without extensive surgical extirpation and morbidity. Because such big lesions may represent atypical lipomas or liposarcomas, care must be taken to remove the entire tumor.

Adult↗
PubMed1991

Erythroderma as the initial presentation of the acquired immunodeficiency syndrome.

A 32-year-old black homosexual man, seronegative for human immunodeficiency virus antibody, presented with erythroderma. His peripheral blood was significant for circulating Sézary-like cells bearing the CD8(+) phenotype. Eighty-eight percent of his lymphocytes were CD8(+) as well. He seroconverted 3 months after the initial presentation. We conclude that erythroderma was the presenting sign of the acquired immunodeficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Verrucous carcinoma of a leg amputation stump.

Verrucous carcinoma of the skin is a rare cancer which tends to appear on the soles of the feet, although it can appear elsewhere on the cutaneous surface. It has not, to our knowledge, been previously reported on a leg amputation stump.

Aged↗
PubMed1991

Sweet's syndrome with acute leukemia.

Sweet's syndrome presenting with malignancy or acute neutrophilic dermatosis is an unusual cutaneous disorder associated most commonly with acute myelogenous leukemia. Although other cancers may be linked to acute neutrophilic dermatosis, a large majority of patients have associated neoplasms of hematopoietic, plasma cell, or lymphoid nature. We report a patient with aplastic anemia who showed acute neutrophilic dermatosis and, ultimately, acute leukemia. The individual lesions responded to carbon dioxide laser surgery.

Acute Disease↗
PubMed1991

Buschke-Löwenstein tumor: verrucous carcinoma of the anogenitalia.

Buschke-Löwenstein tumor is a rare type of anogenital squamous cell carcinoma with a distinctive clinical appearance. We present the case of a thirty-four-year-old man with this tumor, which was excised surgically. Human papillomavirus was detected in formalin-fixed, paraffin-embedded sections with a human papillomavirus 6/11 probe, but not with a human papillomavirus 16 or a human papillomavirus 18 probe.

Adult↗
PubMed1991

Epidermolytic hyperkeratosis treated with etretinate.

Epidermolytic hyperkeratosis is an unusual type of ichthyosis that may be characterized in extreme cases by massive cutaneous involvement resembling a porcupine. We present such a patient who had a remarkable response to treatment with oral etretinate.

Adult↗
PubMed1990

Correction of the ultraviolet light induced DNA-repair defect in xeroderma pigmentosum cells by electroporation of a normal human endonuclease.

Cells from patients with xeroderma pigmentosum, complementation group A (XPA), are known to be defective in repair of pyrimidine dimers and other forms of damage produced by 254-nm ultraviolet (UVC) radiation. We have isolated a DNA endonuclease, pI 7.6, from the chromatin of normal human lymphoblastoid cells which recognizes damage produced by UVC light, and have introduced this endonuclease into UVC-irradiated XPA cells in culture to determine whether it can restore their markedly deficient DNA repair-related unscheduled DNA synthesis (UDS). Introduction of the normal endonuclease, which recognizes predominantly pyrimidine dimers, but not the corresponding XPA endonuclease into UVC-irradiated XPA cells restored their levels of UDS to approximately 80% of normal values. Electroporation of both the normal and the XPA endonuclease into normal human cells increases UDS in normal cells to higher than normal values. These results indicate that the normal endonuclease can restore UDS in UVC-irradiated XPA cells. They also indicate that XPA cells have an endonuclease capable of increasing the efficiency of repair of UVC damage in normal cells.

Cell Line, Transformed↗