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Biomedical subjects

T Kuo

Publications and source records attributed to T Kuo.

54 records · Page 3Linked to original sources
PubMed1982

Pyridine nucleotide specificity of barley nitrate reductase.

NADPH nitrate reductase activity in higher plants has been attributed to the presence of NAD(P)H bispecific nitrate reductases and to the presence of phosphatases capable of hydrolyzing NADPH to NADH. To determine which of these conditions exist in barley (Hordeum vulgare L. cv. Steptoe), we characterized the NADH and NADPH nitrate reductase activities in crude and affinity-chromatography-purified enzyme preparations. The pH optima were 7.5 for NADH and 6 to 6.5 for the NADPH nitrate reductase activities. The ratio of NADPH to NADH nitrate reductase activities was much greater in crude extracts than it was in a purified enzyme preparation. However, this difference was eliminated when the NADPH assays were conducted in the presence of lactate dehydrogenase and pyruvate to eliminate NADH competitively. The addition of lactate dehydrogenase and pyruvate to NADPH nitrate reductase assay media eliminated 80 to 95% of the NADPH nitrate reductase activity in crude extracts. These results suggest that a substantial portion of the NADPH nitrate reductase activity in barley crude extracts results from enzyme(s) capable of converting NADPH to NADH. This conversion may be due to a phosphatase, since phosphate and fluoride inhibited NADPH nitrate reductase activity to a greater extent than the NADH activity. The NADPH activity of the purified nitrate reductase appears to be an inherent property of the barley enzyme, because it was not affected by lactate dehydrogenase and pyruvate. Furthermore, inorganic phosphate did not accumulate in the assay media, indicating that NADPH was not converted to NADH. The wild type barley nitrate reductase is a NADH-specific enzyme with a slight capacity to use NADPH.

Journal Article↗
PubMed1981

Cutaneous extramedullary hematopoiesis presenting as leg ulcers.

A case of cutaneous extramedullary hematopoiesis was manifest as bilateral leg ulcers in a patient with myelofibrosis. Six similar cases have been reported previously, although the new case represented an entirely new clinical manifestation. The cutaneous lesions were previously described as erythematous papules, nodules, or plaques. Among these seven cases, myeloid series only or myeloid and erythroid series, with of without megakaryocytes, were found in the cutaneous lesions. All three marrow elements were observed in the ulcers of the present case. The possibility of extramedullary hematopoiesis should be considered in a patient who has myelofibrosis with unusual cutaneous eruptions.

Aged↗
PubMed1981

Monstrous epithelial cells in human epididymis and seminal vesicles. A pseudomalignant change.

Peculiar monstrous epithelial cells simulating anaplastic malignant transformation were observed in human epididymis and seminal vesicles. In epididymis, scattered hyperchromatic giant epithelial cells were seen protruding into the lumina of ductuli efferentes in 12 of 43 specimens examined (28%). Eight cases were seen in cancer patients and four cases in noncancer patients. In seminal vesicles, epithelial cells exhibiting nuclear hypertrophy, hyperchromatism, and transformation into a variety of grotesquely shaped nuclei were observed in 24 of 32 specimens examined (75%). Fourteen cases were seen in cancer patients and 10 cases in noncancer patients. Since the peculiar epithelial changes were observed in both cancer and noncancer patients, this phenomenon represented a histologically pseudomalignant condition. In both organs, the group of patients without atypical epithelial changes were younger. Generally, the pseudomalignant changes were not seen in persons under the age of 20. There was no correlation to any particular systemic disease. The histogenesis remains speculative, but hormonal effects or degeneration due to aging seem to be contributory. The most important aspect of these observations, however, is that the changes described should not be mistaken for cancer. In addition, eosinophilic hyaline bodies were frequently observed in the muscle layer of seminal vesicles. The nature and the significance of their occurrence is unknown.

Adolescent↗
PubMed1980

Endometriosis occurring in leiomyomatosis peritonealis disseminata: ultrastructural study and histogenetic consideration.

Leiomyomatosis peritonealis disseminata is a pseudomalignant condition which mimics disseminated abdominal carcinoma. A new case is reported and compared to the 11 well-documented cases in the literature. All reported patients have experienced a benign clinical course. The peritoneal nodules are composed of histologically benign-appearing smooth-muscle cells, substantiated by electron-microscopic study. The histogenesis of this entity is discussed in the light of our ultrastructural findings and the observation of concurrent endometriosis. The theory of metaplasia of the subcoelomic mesenchyme in the pathogenesis of the leiomyomatous lesions is favored. The serum estrogen levels determined in our patient did not reveal any abnormal change. The inducing factor(s) remain to be identified. Also, an unusual sensitivity of the coelomic tissues in these patients, in response to metaplastic stimuli, is postulated as a possible contributing factor.

Adult↗
PubMed1980

Clear cell carcinoma of the skin. A variant of the squamous cell carcinoma that simulates sebaceous carcinoma.

Certain clear-cell carcinomas of the skin observed in elderly caucasian men with a history of excessive sun exposure and multiple skin neoplasms may be mistaken for sebaceous carcinomas or other cutaneous clear-cell tumors. These tumors are believed to be variants of squamous cell carcinoma undergoing extensive hydropic change which results in the clear-cell appearance. They are classified into three histologic types. Type I and type III tumors are either primary or recurrent squamous-cell carcinomas. The histogenesis of type II tumors is uncertain but they may represent recurrent metastatic tumors from the previously excised, adjacent epidermal squamous-cell carcinomas; however, the possibility that they are primary adnexal tumors of undetermined histogenesis remains to be determined. Various techniques of staining, as well as differences in histologic appearance, assist in the differential diagnosis of these and other cutaneous clear-cell neoplasms.

Adenocarcinoma↗
PubMed1979

Papillary endothelial proliferation in cystic lymphangiomas. A lymphatic vessel counterpart of Masson's vegetant intravascular hemangioendothelioma.

Papillary endothelial proliferation similar to that of Masson's "vegetant intravascular hemangioendothelioma" of the blood vessels was observed in two cases of cystic lymphangiomas. They are believed to be the lymphatic vessel counterpart of Masson's entity. Twenty-five other specimens of various lymphangiomas examined (18 patients) did not contain the same change. As was emphasized previously for Masson's lesions, lymphangiomas containing similar endothelial changes should also not be mistaken for malignant vascular tumors, since in these two cases, no unusual clinical course supervened. Although the histogenesis of the lesion as proposed by Masson has been disputed, both primary and secondary endothelial proliferation seem to remain possible in the formation of these lesions.

Cell Division↗
PubMed1976

Masson's "vegetant intravascular hemangioendothelioma:" a lesion often mistaken for angiosarcoma: study of seventeen cases located in the skin and soft tissues.

The occurrence of Masson's "hemangio-endotheliome vegetant intravasculaire" (Masson's pseudoangiosarcoma) in the skin and soft tissues is illustrated with 17 surgically excised specimens. Two forms are recognized; it may appear either as a pure lesion or as a focal condition in a pre-existing vascular process, such as pyogenic granuloma or hemangioma. The clinical appearance is not specific and the diagnosis can only be established by microscopic examination. It shows a predilection for the head and extremities. Its characteristic morphologic appearance makes possible its differentiation from a group of benign and malignant vascular proliferations. The key microscopic feature is the presence of a papillary growth composed of hyperplastic endothelial cells supported by delicate fibrous stalks entirely confined within the vascular lumen. The lesion should not be mistaken for angiosarcoma, since its clinical behavior is invariably benign.

Diagnosis, Differential↗
PubMed1976

Differential accumulation of proteinase inhibitor I in normal and crown gall tissue of tobacco, tomato, and potato.

A proteinase inhibitor (inhibitor I) is induced in crown gall tumors of tobacco (Nicotiana tabacum) initiated through infection with the tumorinducing bacterium, Agrobacterium tumefaciens, strains B6 or CG-14. Uninfected tissues do not contain immunologically detectable quantities of inhibitor I. Inhibitor I synthesis in tobacco crown gall tumors paralleled tumor growth at the average rate of about 4.5 mug of inhibitor I per 200 mg of fresh tissue per day. Infection of variegated tobacco mutant Dp-I with A. tumefaciens strain CG-14 produced tumors with 25% more inhibitor than tumors induced with strain B6. Unlike tobacco, tumors induced by either bacterial strain on potato (Solanum tuberosum) and on tomato (Lycopersicum esculentum) did not accumulate inhibitor I. Consequently, inhibitor I accumulation is modulated by the type of plant host used in spite of familial relatedness (Solanaceae) and the strain of A. tumefaciens used for infection.Immunological and electrophoretic properties of inhibitor I from tobacco crown gall tumor, callus, etiolated, and variegated tissues were compared. Agar immunodiffusion assays showed no apparent differences among precipitin reaction lines between inhibitor I of tumor, callus, variegated, and etiolated tissues. The immunoelectrophoretic mobilities of inhibitor I of tumor, variegated, and etiolated tissues were the same, but differed from that of either normal or crown gall callus tissues. These results suggest that different isoinhibitors of inhibitor I could account for the observed differences in electrophoretic mobilities, or that modification of the inhibitor has occurred sometime during, or after, its synthesis.

Journal Article↗
PubMed1976

Cutaneous extramedullary hematopoiesis.

An asymptomatic skin nodule in a patient with myelofibrosis was shown to consist of extramedullary hematopoiesis. It was a soft bluish nodule that resembled a hemangioma. Microscopically, both erythroid and myeloid cells, but not megakaryocytes, were found. This case demonstrates the ability of the skin to recapitulate dermal hematopoiesis seen in a stage of human fetal development.

Aged↗
PubMed1975

Clonal growth of hamster free alveolar cells in soft agar.

Free alveolar cells obtained from healthy unstimulated hamsters were tested for their ability to form colonies in soft agar. Every bronchial washing so far tested contained colon-forming cells. The average plating efficiency was 8.1% (2.4-18.3%). Alveolar colony-forming cells were characterized by having a long initial lag period (4-8 days) and only mononuclear phagocytes were found in the colony. Medium conditioned by baby hamster kidney cells or other cells was required for the initiation and maintenance of their growth. Alveolar cells from normal mice and rats also formed colonies under appropriate culture conditions.

Agar↗
PubMed1972

Immunological Comparisons of Chymotrypsin Inhibitor I among Several Genera of the Solanaceae.

Microcomplement fixation was employed to compare the immunological differences that occur between purified inhibitor I from potato tubers, the four purified protomers that comprise it, and inhibitor I from tuber and leaf extracts. Total inhibitors of chymotrypsin and trypsin in leaves of seven genera of the Solanaceae were identified by enzymatic assay. In leaves of three genera, Solanum, Lycopersicum, and Datura, chymotrypsin inhibitor I was identified immunologically. In petals of all seven genera inhibitor I was also identified immunologically. With the microcomplement fixation technique inhibitor I from leaf or petal extracts of eight Solanaceae genera were compared. An immunological relationship of inhibitor I among seven of these genera was established.

Journal Article↗