Search PubMed⌕ Search

Biomedical subjects

L T Yam

Publications and source records attributed to L T Yam.

At least 91 records · Page 5Linked to original sources
PubMed1982

Enzyme immunoassay for tartrate-resistant acid phosphatase.

An immunochemical method for quantitative analysis of the tartrate-resistant acid phosphatase (EC 3.1.3.2), band 5, is presented. This method involves precipitation of the enzyme from the serum by the antibody specific to band 5 and by sheep anti-rabbit immunoglobulin, followed by analysis of the enzyme activity in the precipitate. The precipitation procedure eliminates the interferences of the tartrate-sensitive phosphatase of all tissues, of the tartrate-resistant phosphatase of erythrocytes, and of unknown substances that interfere with the colorimetric method. We compare the present method with previously described colorimetric and electrophoretic methods.

Acid Phosphatase↗
PubMed1982

Therapeutic leukapheresis in hairy cell leukemia.

Therapeutic leukapheresis was performed on three patients, and plasmapheresis on two patients with far-advanced hairy cell leukemia. Two of the three patients who were treated with leukapheresis had many hairy cells in their peripheral blood, while the other had relatively few. In each patient, dramatic clinical and hematologic improvements were observed that have sustained for more than 23, 10, and 26 months, respectively. Plasmapheresis of similar intensity failed to show any appreciable therapeutic effects on two other patients with similar clinical and hematologic findings. We believe that the favorable therapeutic effects of leukapheresis are due to the removal of factors capable of inhibiting normal hematopoiesis. This factor(s) is present in the cells that were removed by leukapheresis. The exact nature of this factor(s) or the cells that produce this factor(s) remains to be identified.

Adult↗
PubMed1982

Bilateral occlusion of the central retinal artery associated with hyperglobulinemia in hairy cell leukemia.

A 49-year-old man with hairy cell leukemia experienced occlusion of both central retinal arteries in a 6-day period. Hyperglobulinemia was noted; however, immunoperoxidase studies failed to demonstrate that the hairy cells had produced the excess immunoglobulins. None of the other, more common, causes of occlusion of the central retinal artery were present. Plasmapheresis, in addition to more traditional methods of treatment, resulted in stabilization of the patient's vision. Subsequent fluorescein angiography revealed markedly diminished choroidal perfusion as well as delayed retinal perfusion. This appears to be the first account of bilateral occlusion of the central retinal artery secondary to a hyperviscosity syndrome, as well as the first description of ocular involvement by hairy cell leukemia. Speculation as to how the hyperglobulinemia related to the ocular manifestations is offered.

Arterial Occlusive Diseases↗
PubMed1981

Comparison of tartrate-resistant acid phosphatase in normal mouse tissues to that in the reticulum cells of leukemic reticuloendotheliosis.

A strong activity of the tartrate-resistant acid phosphatase, isoenzyme 5b, was observed in mouse spleen. The enzyme of the mouse spleen had similar electrophoretic mobility and related antigenicity to that of the reticulum cells of leukemic reticuloendotheliosis. Enzyme histochemical studies showed many non-phagocytic cells with strong tartrate-resistant acid phosphatase in spleen. The data suggest that mouse tissue is a good animal model to study the normal cell type with strong tartrate-resistant acid phosphatase.

Acid Phosphatase↗
PubMed1981

Chemotherapy of vinyl chloride-associated hepatic angiosarcoma.

The use of systemic chemotherapy was studied in a group of four patients who had hepatic angiosarcoma in association with exposure to vinyl chloride. All of the patients received Adriamycin 60 mg/m2 i.v. q3-4 weeks and in three patients this was combined with Cytoxan 600 mg/m2 and methotrexate 20 mg/m2. Three patients had an objective response lasting four, nine, and ten months. One patient had stable disease for ten months. Responding patients maintained an excellent performance status during therapy. Following evidence of progressive disease, patients died in three, four, and six months. Survival from the time of diagnosis was 11, 13, 15 and 53+ months. Sufficient data are not available from these patients to recommend a specific drug or combination for use in hepatic angiosarcoma, but our data indicate that chemotherapy can improve quality and duration of survival.

Adult↗
PubMed1981

Orbital metastasis from prostatic carcinoma. Identification by an immunoperoxidase technique.

A patient was seen initially with an orbital tumor causing blindness of the left eye. Although disseminated prostatic carcinoma was found, the origin of the orbital tumor was not established until prostate antigen was demonstrated in biopsy specimens by an immunoperoxidase technique. Orbital metastasis from prostatic carcinoma has been reported in 16 cases. Confirmation of the diagnosis may be difficult and, in the past, has largely been indirect as judged by clinical trial. The immunoperoxidase technique for detecting prostate antigen in tissue sections is both sensitive and specific. Application of this technique resulted in the diagnosis of this technique resulted in the diagnosis of this unusual manifestation of metastatic prostate cancer. The possibility of additional clinical applications of this immunohistochemical technique within the field of ophthalmology is raised.

Adenocarcinoma↗
PubMed1981

Immunohistochemistry of prostatic acid phosphatase.

The human prostatic acid phosphatase is a specific marker for the prostatic epithelial cells. By using an immunoperoxidase staining method for this enzyme, it is possible both to identify the prostatic epithelial cells and to recognize the prostatic origin of metastatic lesions of prostate cancer. Of the tissues containing prostatic epithelial cells from 120 patients, positive staining reaction was detected in 114 (95%), and negative in 6. In nonprostatic tissues from 242 patients, weak but positive staining reaction was detected in 8 (3.3%), including tissues from one renal cell carcinoma and 7 breast carcinomas. Of 27 patients in whom tumor tissues were tested at a time when tumor origin was unknown, the staining reaction was positive in 14 patients later found to have prostate cancer. It was negative in 6 patients with nonprostatic carcinoma and 7 patients with carcinoma of unknown primary. Although this immunohistochemical technique for prostatic acid phosphatase appears promising in diagnosing metastatic prostate cancer, its clinical significance and limitations remain unclear, and there are considerable technical problems yet to be solved. These problems are best approached by joint collaborative efforts of the various investigators interested in prostate cancer.

Acid Phosphatase↗
PubMed1981

Occupational carcinogenesis: the Louisville experience with vinyl chloride-associated hepatic angiosarcoma.

Hepatic angiosarcoma in man was first associated with exposure to vinyl chloride in Louisville, Kentucky, where it was identified in 10 persons from a single vinyl chloride polymerization plant; clinical manifestations are summarized herein. Following prolonged exposure to vinyl chloride, the onset of this disease is insidious and the clinical picture is that of nonspecific hepatic injury with mildly abnormal biochemical liver test results. Carcinoembryonic antigen and alpha fetoprotein are undetectable. Radionuclide and angiographic studies of liver show characteristic but nondiagnostic abnormalities. A definite diagnosis is usually made only by open liver biopsy. Treatment is unsatisfactory but chemotherapy seems to prolong survival. Average survival from diagnosis is about 12 months. Overt liver failure usually occurs only as a preterminal event and was the major cause of death in all of our patients. Preventive measures are now in effect in the plant. This experience illustrates the importance of the clinician in occupationally-related cancer.

Hemangiosarcoma↗
PubMed1981

Comparison of the tartrate-resistant acid phosphatase in Gaucher's disease and leukemic reticuloendotheliosis.

Tartrate-resistant acid phosphatase was isolated from serum and spleen of patients affected by Gaucher's disease. Electrophoretic and antigenic properties were compared to the enzyme isolated from hairy cells described in a previous study (9). The enzyme isolated from Gaucher serum has electrophoretic and antigenic properties identical to the acid phosphatase band 5b of hairy cells. The major tartrate-resistant acid phosphatase in the Gaucher spleen is band 5a. Bands 5a and 5b have identical protein structure indicated by their identical antigenicity. The removal of carbohydrate from band 5a by sialidase converted band 5a to 5b.

Acid Phosphatase↗
PubMed1981

Unusual manifestations of hypereosinophilia.

The hypereosinophilic syndrome is a heterogeneous group of clinical disorders comprising a spectrum of pathologic conditions. We have described a patient with chronic eosinophilia for eight years. His course of progressive organ dysfunction and tissue infiltration by eosinophils, with myelofibrosis, lytic bone lesions, hepatomegaly, and generalized adenopathy are most compatible with a chronic myeloproliferative syndrome.

Chronic Disease↗
PubMed1981

Presence of "prostatic" acid phosphatase in human neutrophils.

The occurrence of natural substances with antigenic properties similar to those of the prostatic acid phosphatase was examined in one patient with neutrophilic leukemia and increased activity of serum acid phosphatase. The fraction responsible for the increased serum enzyme activity was tartrate sensitive and was identified as isoenzyme 2 by polyacrylamide gel electrophoresis. This isoenzyme originated from the leukocytes but had similar electromobility to that of the prostatic acid phosphatase isoenzyme 2. Immunohistochemical and counterimmunoelectrophoretic studies indicated that this leukocytic isoenzyme was present in the neutrophils and shared antigenic properties with the prostatic isoenzyme 2. Leukocytes from one patient with acute granulocytic leukemia, two patients with polycythemia vera with neutrophilia, and five normal subjects also contained this prostatic acid phosphatase like isoenzyme. Elevated serum "prostatic" acid phosphatase activity, therefore, may be found not only in prostatic cancer but also in granulocytic leukemia and perhaps other diseases.

Acid Phosphatase↗
PubMed1981

A simple immunohistochemical method for the detection of prostatic acid phosphatase.

A simplified immunohistochemical method was developed to identify prostatic cells in paraffin sections for the diagnosis of primary or metastatic prostatic carcinoma. By incubating each section with a specific antiserum, followed by incubation with a specific acid phosphatase isoenzyme of the prostate, the antibody binding site is visualized by staining for acid phosphatase activity in the glandular epithelial cells of the prostate and in the metastatic prostate carcinoma cells that involve the lymph node. The present method is simpler and more specific than the previously described indirect immunoperoxidase method.

Acid Phosphatase↗
PubMed1980

Immunohistochemical diagnosis of prostatic cancer with metastasis.

An immunohistochemical method for detecting prostatic acid phosphatase is described for the diagnosis of metastatic prostatic carcinoma. The specific antiserum against prostatic acid phosphatase was prepared from rabbit by injection of acid phosphatase purified from seminal fluid. This method gives a selective staining of the cytoplasm of the glandular epithelial cells of prostatic tissue specimens on paraffin section. Most of the non-prostatic tissues were negative except for occasional weak staining in granulocytes, islet cells of pancreas, parietal cells of stomach, tubular epithelial cells of kidney, and liver cells. Also examined were 50 consecutive cases of metastatic tumor involving the bone marrow and 5 cases of metastatic prostatic carcinoma involving the lymph node or lung. All 20 cases with prostatic primary lesion showed positive staining. All other cases were negative, except 5 of the 14 cases of metastatic breast carcinoma in women showing weakly positive results. The method is fairly specific for identification of metastatic prostatic carcinoma. Occasional positive staining in breast tumor needs further study to establish whether the staining is due to the same isoenzyme or to certain cross immunoreactivity.

Acid Phosphatase↗
PubMed1980

Elevation of serum acid phosphatase in cancers with bone metastasis.

In patients with nonprostatic cancer serum acid phosphatase activity is usually elevated when bone metastasis is present but not when bone metastasis is absent. The fraction responsible for serum enzyme elevation is a normal component of serum; it appears in gel electrophoresis as band 5; and is tartrate-resistant. It is suggested that the origin of acid phosphatase elevation is bone osteoclasts rather than cancer tissue, as is the case with prostatic carcinoma. Determination of serum acid phosphatase activity may be useful in the detection of bone metastasis.

Acid Phosphatase↗
PubMed1980

Eosinophilia in systemic mastocytosis.

The diagnosis of systemic mastocytosis depends on the proper recognition of extensive mast cells infiltration in tissues. Accurate identification of the mast cells in tissues may be difficult when there is no clinical suspicion to initiate a special search for these cells. Four patients with atypical clinical features and eosinophilia in tissues and three with eosinophilia in blood had hematologic or histologic findings suggestive of myelofibrosis with myeloid metaplasia, and malignant lymphoma. It was the presence of blood and tissue eosinophilia in these patients that led to further investigation and recognition of the diagnosis of systemic mastocytosis. Methods for identification of the mast cells are examined. The combined use of Wright-Giemsa stain, toluidine blue, and aminocaproate esterase is preferred. The eosinophils are intimately related to the mast cells. In cases of eosinophilia of unknown etiology, systemic mastocytosis should be considered one of the possible etiologic factors.

Aged↗