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K Clausen

Publications and source records attributed to K Clausen.

16 recordsLinked to original sources
PubMed1998

Providing human tissues for research: how to establish a program.

The Cooperative Human Tissue Network is a group composed of cooperating academic institutions that supply human tissues to researchers studying a wide range of neoplastic and other diseases. The experience of the Cooperative Human Tissue Network in establishing methods of prospective tissue collection and in developing tumor banks is discussed to aid institutions in establishing tissue resources for their local investigators, who may wish to use human tissues in current or future research projects. The advantages to pathology departments and to associated medical institutions of establishing an organized tissue resource include ensuring proper institutional review board approval of research projects using human tissues, protecting diagnostic specimens, creating new opportunities for extramural research, increasing the speed of diagnostic specimen transport to surgical pathology, and providing educational and research opportunities for pathologists and pathology residents. Methods of tissue collection, processing, storage, data collection, and supply are outlined. Also, resources necessary to begin organized tissue collection, including personnel, space, equipment, and supplies, are discussed.

Female↗
PubMed1988

Use of polar solvents in chemoprevention of 1,2-dimethylhydrazine-induced colon cancer.

To examine the effect of the polar solvents on 1,2-dimethylhydrazine (DMH)-induced colon cancer, 100 male Sprague-Dawley rats were randomly allocated to a control and three treatment groups. Treated animals received N-methylformamide (NMF), dimethylsulfoxide (DMSO), or methylsulfonylmethane (MSM) added to drinking water 1 week before carcinogen injections commenced and for the duration of the experiment. Primary tumors were detected by serial laparotomy under ether anesthesia performed at 2-month intervals and commencing after carcinogen injections had been completed. The average time to tumor onset was significantly delayed in rats receiving NMF and MSM (P = 0.0141 and 0.0398 respectively, Mantel-Haenszel test). In addition, fewer poorly differentiated tumors were noted in treatment groups. No weight loss or toxicity was observed. These findings demonstrate that the polar solvents significantly reduce the latent period to tumor onset in DMH-induced colon cancer and indicate the need to further investigate such compounds as chemopreventive agents.

1,2-Dimethylhydrazine↗
PubMed1984

Evidence of a peptide backbone contribution toward selective receptor recognition for leucine enkephalin thioamide analogs.

The in vitro opioid activities of a series of leucine enkephalin analogs containing a thioamide linkage in place of the peptide bond at various positions of the backbone were determined in mu- and delta-receptor-selective bio- and binding-assays. Thioamide substitution in the 1-2 position resulted in an inactive compound, whereas the same modification in the 2-3 and 4-5 position produced potency enhancement. Most interestingly, the 2-3 modified analog showed a 3 to 5 times higher preference for delta- over mu-receptors than natural leucine enkephalin. These results suggest that subtle backbone modifications can have a profound effect on receptor affinity and selectivity of biologically active peptides.

Amides↗
PubMed1983

The extent of primary melanoma excision. A re-evaluation--how wide is wide?

A retrospective review of 118 clinical Stage I melanoma patients, including the re-examination of histologic slides in 57 cases, was performed to define factors important to survival. The majority (76.7%) had excision margins of 30 mm or less (range = 6-85 mm, mean--29.3 mm). The adjusted 5-year survival was 77.3%. Local recurrences within 5 cm of the primary closure scar developed in 3.4%. The recurrences occurred in patients with satellitosis (1), unrecognized subclinical Stage II disease (1), or as the first evidence of disseminated Stage III disease (2). Margins less than 20 mm were associated with an increased risk of dying if the tumor diameter was more than 10 mm (p = 0.0105) or if the depth of invasion was more than 2.0 mm (p = 0.0491). Increasing the margin to 25 mm improved survival. However, no further protection was evident for margins over 30 mm. For smaller and shallower lesions, no optimal margin could be identified. It appears that a 30 mm margin is adequate for large and deep clinical Stage I melanomas, and mortality and local recurrences are due to factors other than the extent of excision.

Adolescent↗
PubMed1983

The geometry of the thiopeptide unit.

The structure of the modified dipeptide Z-Glyt-Gly-OBzl is reported with special emphasis on the linear and angular dimensions of the thiopeptide unit. It is shown that, except for the differences between the carbonyl and the thioacyl bond lengths, there are no significant differences between the oxopeptide and the thiopeptide unit.

Amino Acids, Sulfur↗
PubMed1982

Carcinoma in a colon conduit urinary diversion.

In recent years urinary diversion by means of the colon conduit has gained popularity because of the failure to exhibit reflux and the lower incidence of stomal stenosis. However, colon conduit diversion may be associated with adenocarcinoma, as is ureterosigmoidostomy. We report the first occurrence of adenocarcinoma in a colon conduit and, perhaps more important, in a colon conduit in which there had never been a fecal stream.

Adenocarcinoma↗
PubMed1982

Kaposi's sarcoma: endoscopic observations of gastric and colon involvement.

Kaposi's sarcoma is a multisystem neoplastic disease in which skin manifestations are usually seen first. Visceral involvement is frequent and the gastrointestinal tract is the most common location. We report a patient with Kaposi's sarcoma in whom the typical violaceous skin lesions were the sarcoma in whom the typical violaceous skin lesions were the only overt clinical manifestations, but the patient had multiple macular angiodysplastic-like lesions on colonoscopy. In contrast to the uniform appearance of the colonic lesions, polypoid, volcano, and maculopapular lesions were seen in the stomach on endoscopy. This report provides probably the first endoscopic description of the colonic lesions of Kaposi's sarcoma and contrasts them with the typical upper gastrointestinal lesions. A thorough gastrointestinal survey should be performed in all patients with Kaposi's sarcoma to delineate involvement, since appropriate treatment will be dictated by the presence or absence of visceral involvement.

Aged↗
PubMed1980

X-linked lymphoproliferative syndrome registry report.

Immune deficiency, especially to the Epstein-Barr virus, and increased susceptibility to fatal infectious mononucleosis, acquired agammoglobulinemia, and lymphoma are the cardinal features of the X-linked lymphoproliferative syndrome. Since the establishment of the XLP Registry in September, 1978, 59 affected males in seven unrelated kindreds were comprehensively studied. A spectrum of lymphoproliferative phenotypes was observed. Thirty-four patients (57%) died from infectious mononucleosis, eight (14%) had fatal infectious mononucleosis with lymphoma (immunoblastic sarcoma), nine (15%) had depressed immunity following EBV infection, and eight (14%) developed lymphoma. Several patients with XLP lacked EBV antibodies despite infection by EBV. The results of this study suggest that EBV can be an oncogenic agent in patients who are immune deficient with XLP.

Adolescent↗
PubMed1979

Chronic and recurrent appendicitis.

Acute appendicitis is a well known clinical entity, but many physicians are unwilling to accept appendicitis as a chronic or recurrent illness. Of 225 patients undergoing appendectomy, sixteen (7 per cent) had findings suggestive of chronic, recurrent, or subacute appendicitis. Four patients had chronic abdominal pain and histologic findings of chronic inflammation. Nine patients had previous episodes similar to that which resulted in appendectomy. All had acute suppurative appendicitis pathologically. Three patients had only one episode of abdominal pain, but had pathologic evidence of subacute inflammation. Because this study was retrospective, we suspect that the true incidence of recurrent appendicitis is significantly greater, as reported by others. Indications for operation must be strict, for unless there are specific signs and symptoms of appendiceal disease, appendectomy will often be of no benefit.

Abdomen↗
PubMed1977

Atypical sweat duct hyperplasia accompanying keratoacanthoma.

25 cases of atypical sweat duct proliferation in association with cutaneous tumors are described. 20 of these were keratoacanthomas. The compression of the duct either in its dermal or intraepidermal portion is considered to be the etiology. Similar changes are seen with decubitus ulcer and stasis dermatitis. Atypical sweat duct hyperplasia may be useful as an extra aid in the differentiation of keratoacanthoma from well-differentiated squamous cell carcinoma.

Carcinoma, Squamous Cell↗