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L T Yam

Publications and source records attributed to L T Yam.

At least 55 records · Page 3Linked to original sources
PubMed1987

Clinical significance of tartrate-sensitive and tartrate-resistant acid phosphatase indicated from the study of their biosynthetic mechanism.

The tartrate-sensitive prostatic acid phosphatase, bands 2 and 4, are found in the soluble cytosol, and absent in the polysome of the prostate, while the tartrate-resistant acid phosphatase band 5 is present in the polysome and the soluble cytosol of hairy cells. The mRNA isolated from the prostate catalyzes the incorporation of 3T leucine into a protein different from that of bands 2 and 4. On the other hand, the mRNA isolated from the hairy cells catalyzes the incorporation of 3T leucine into band 5. The different biosynthetic mechanism of these two types of acid phosphatases are discussed in light of their different clinical significance.

Acid Phosphatase↗
PubMed1987

Cytochemistry of tartrate-resistant acid phosphatase: 15 years' experience.

Tartrate-resistant acid phosphatase (T-AcP) has been used in the past 15 years as a specific test for the diagnosis of hairy cell leukemia (HCL). However, enzyme activity has been reported to be absent from the hairy cells of rare cases of HCL and to be present in the neoplastic cells of diseases other than HCL. In order to fully utilize T-AcP for the diagnosis of HCL, it is necessary to maximize the sensitivity and specificity of the staining method, to have adequate quality control to ensure technical and interpretative accuracy, and to prepare optimal cytologic and histologic materials for study. In blood, only the presence of cells with intense T-AcP activity is diagnostic of HCL (positive T-AcP test). In tissues other than blood, the presence of cells with intense enzyme activity may not be diagnostic for HCL; assessment of cell morphology and appreciation of the pattern of enzyme localization are also important. In studying the blood of over 1,000 patients, we have found a negative T-AcP test in two of 200 cases of HCL and a positive T-AcP test in three of 800 patients with diseases other than HCL. We believe that the T-AcP test, when performed and interpreted properly, is a useful diagnostic test for HCL.

Acid Phosphatase↗
PubMed1986

Diagnosis of B-cell non-Hodgkin's lymphoma of the central nervous system by immunocytochemical analysis of cerebrospinal fluid lymphocytes.

Diagnosis of central nervous system (CNS) non-Hodgkin's lymphomas may be difficult despite the use of sophisticated scans and routine cytologic methods. The use of an immunoalkaline phosphatase technique to examine cerebrospinal fluid (CSF) containing many mononuclear cells is described. Monoclonal proliferations of B-lymphocytes were demonstrated in six patients with neurologic abnormalities, whose clinical findings and subsequent clinical courses were those of lymphoma. The diagnosis of CNS lymphoma could not be made, despite multiple diagnostic procedures, until the immunocytochemical studies were performed. In three other patients, a lymphoproliferative disorder was suspected; however, examination of CSF showed many T-lymphocytes but no monoclonal B-lymphocytes, consistent with a reactive lymphocytosis. The subsequent clinical courses of these patients have shown no evidence of CNS lymphoma. Immunocytochemical studies of CSF lymphocytes are useful in differentiating benign from malignant proliferations.

Adult↗
PubMed1986

Monoclonal antibody specific to acid phosphatase isoenzyme 4.

Prostatic acid phosphatase isoenzyme 4 was purified by ion exchange column chromatography, followed by high pressure liquid chromatography. The highly purified enzyme was used to produce monoclonal antibody from immunized BALB/c mice. The antibody was specific to isoenzyme 4, with negligible affinity to isoenzyme 2. The specificity of the monoclonal antibody was evaluated by Western blot analysis and by inhibition of radioimmunoassay. Immunohistochemistry method using the antibody to isoenzyme 2 showed heavy staining on the cell surface in contrast to the even staining throughout the cytoplasm when monoclonal anti-isoenzyme 4 was used. These results reflect the secretory nature of isoenzyme 2 and the non-secretory nature of isoenzyme 4.

Acid Phosphatase↗
PubMed1986

Hepatic involvement in systemic mast cell disease.

Thirteen patients with systemic mast cell disease were studied in order to define the hepatic changes in this disease and to correlate the histologic lesions in the liver with the clinical findings. These patients often presented with multisystem disorders and 10 had hepatomegaly. Microscopically, the liver tissues in all patients showed fibrosis and chronic inflammatory cellular infiltration with plasma cells, lymphocytes, eosinophils, and mononuclear fibroblast-like cells in the portal area. The hepatic sinusoids were not significantly involved. A histologic diagnosis of systemic mast cell disease is seldom entertained in liver biopsy specimens embedded in paraffin and stained with hematoxylineosin, but can be facilitated in biopsy specimens embedded in plastic such as methacrylate. Tissue mast cells in the cellular infiltrate can be demonstrated best by special staining techniques with Giemsa, toluidine blue, and chloroacetate esterase. The severity of the histologic changes in the liver does not correlate well with the size of the liver or biochemical changes in the blood. Abnormal serum biochemical values were noted primarily in those with dehydration caused by diarrhea and vomiting, and in those with malnutrition. Hepatic function test results were usually normal, except for alkaline phosphatase level, which was elevated in all 13 patients. Although the clinical significance of hepatic involvement in systemic mast cell disease cannot be established with certainty in this study, it is believed that the prognosis of systemic mast cell disease is most intricately related to the systemic effects of mast cell involvement in many other organs, and not to hepatic involvement per se.

Adult↗
PubMed1986

Immunoultrastructural demonstration of prostatic acid phosphatase isoenzyme 2 in prostatic carcinoma.

Human prostatic acid phosphatase isoenzyme 2 (HPAcP-2) was isolated from semen. This purified enzyme was immunized to rabbit to produce polyclonal antibodies. The specificity of the antibodies was tested by Western blot transfer method. Rabbit IgG-peroxidase conjugate was prepared from the antiserum and used to localize HPAcP-2 in prostatic carcinoma. It was found that in the tumor glandular acinus the normal basal cells were replaced by tumor cells containing reaction product. In the tumor cells, the reaction product was seen in the cisternae of rough endoplasmic reticulum (ER) and Golgi apparatus. The secretory vesicles which contained reaction product-stained granules and some amorphous material were seen to fuse with the apical plasma membrane and discharged their content into the glandular lumen. On the other hand, some secretory vesicles in the tumor cells facing to the basement membrane also discharged their similar content into the extracellular spaces. Reaction product-stained granules were found in the interstitial spaces surrounding the tumor cells. These findings suggest that HPAcP-2 is synthesized on the bound ribosomes and discharged into the cisternae of rough ER. The molecules are transported to the Golgi cisternae. After concentration and packaging, HPAcP-2 molecules are then transferred to the secretory vesicles, and discharged into the glandular lumen and to the extracellular spaces. The isoenzyme released in the extracellular space may reach the blood stream through the interstitial spaces or the lymphatic system, resulting in the elevation of serum HPAcPase level in some prostatic cancer patients.

Acid Phosphatase↗
PubMed1986

Acute myelomonocytic leukemia: an unusual variant with both granulocytic and monocytic esterases in the leukemic cells.

By using the combination of alpha-naphthyl butyrate esterase and chloroacetate esterase for cytochemical detection of monocytes and granulocytes, respectively, we examined and identified five adult patients with acute myeloid leukemia whose leukemic cells often (20 to 30%) had the characteristics of both monocytes and granulocytes. All five patients were men, 23 to 82 years of age. Two patients had manifestations of preleukemia. One of these two patients had received treatment for lymphoma for 12 months before acute myelomonocytic leukemia was diagnosed. One patient had gum hypertrophy, and two had leukemia cutis. At the time of initial examination, four patients had blood leukocyte counts higher than 80,000/mm3 and one had leukopenia. Four patients received chemotherapy; three responded temporarily but died within 1 year after the myelomonocytic leukemia had been diagnosed. The patient with leukopenia has remained in complete remission for 2 years. With more frequent use of double esterase stains for classification of acute myeloid leukemias, this variant of acute myelomonocytic leukemia should be detected more often and its clinical behavior should be better understood.

Adult↗
PubMed1986

Cutaneous leukocytoclastic vasculitis complicating hairy cell leukemia (leukemic reticuloendotheliosis).

A patient with hairy cell leukemia (HCL) receiving fluoxymesterone developed cutaneous leukocytoclastic vasculitis. His clinical picture was of purpuric papules and pustules on his chest and limbs. Oral corticosteroid therapy and colchicine therapy were tried, with only minimal improvement. Chemotherapy with pentostatin (2'-deoxycoformycin) resolved the vasculitis and placed the HCL in remission. Fifteen cases of HCL associated with vasculitis have been reported previously. Hairy cell leukemia and vasculitis appear to have more than a coincidental relationship.

Adult↗
PubMed1985

Primary pulmonary lymphoma. A clinical and immunohistochemical study of six cases.

Six patients with lymphomatous lesions primarily involving the pulmonary parenchyma were studied. In these patients, both the history and physical findings were vague and minimal. The laboratory findings also were nonspecific, although the findings of large multiple lesions in the lungs and pleural adhesion or effusion were more consistent with lymphoma. Histologic examination revealed lymphocytic infiltration of the pulmonary parenchyma in all six patients and presence of germinal or growth centers in some areas of the lesions in four. The hilar or mediastinal lymph nodes were not involved in five patients so examined. Immunocytochemical study of cytoplasmic immunoglobulin revealed monoclonal lymphocytic proliferation in five patients and negative staining in one patient. Clinical, histologic, or immunohistochemical studies alone may not be sufficient to detect all of the lymphomatous lesions. The combined use of all of these parameters is more advantageous for accurate diagnosis of these lesions. Treatment is surgical resection. Radiotherapy or chemotherapy are used when residual disease is present after surgery. Three patients died of disseminated lymphoma 96, 42, and 8 months after diagnosis, respectively, and three patients are still alive at 18, 24, and 4 months, respectively.

Aged↗
PubMed1985

Immunoelectron microscopic demonstration of prostatic acid phosphatase in human hyperplastic prostate.

Immunoelectron microscopic studies were done on prostatic tissues obtained from patients with benign hyperplasia. Rabbit IgG-peroxidase conjugate against purified human prostatic acid phosphatase band 2 (HPAP-2) was used for studies. Under the light microscope, the columnar secretory epithelia of prostatic glands showed different intensity and distribution of immunostaining whereas the basal cells were unstained. Under the electron microscope, the secretory epithelial cells often showed electron-dense reaction product in the Golgi apparatus and secretory vesicles and vacuoles, and only sparingly in the cisternae of nuclear envelope and rough ER. Sometimes, fusion of secretory vacuolar membrane and plasma membrane and discharge of the vacuolar contents into the extracellular space were noted. The surfaces of microvilli at the apical portion of the columnar epithelia and the lumen of the glandular acini always showed reaction product. These findings suggest that HPAP-2 may be synthesized in the rough ER and transported to the Golgi apparatus where it is concentrated and transferred to the secretory vesicles and vacuoles. HPAP-2 is finally discharged into the extracellular spaces through exocytosis, a secretory mechanism similar to that of other secretory proteins.

Acid Phosphatase↗
PubMed1985

Immunoalkaline phosphatase cytochemistry. Technical considerations of endogenous phosphatase activity.

The authors have developed an immunoalkaline phosphatase method and have applied it with success to the study of blood cells. They have now observed that macrophages in tissues and in serous effusions may be nonspecifically stained when immunoalkaline phosphatase methods are used. A systematic study of this endogenous macrophage phosphatase activity has shown it to have a pH optimum of 5.0-6.0 (acid phosphatase), but it remains weakly active in the mildly alkaline conditions used in the immunoalkaline phosphatase procedure. At its pH optimum, this macrophage phosphatase is mostly tartrate resistant, however, when 50 mM tartrate is added to a staining medium of pH 7.6-8.0, the residual endogenous phosphatase activity effectively is inhibited. When immunochemical studies are conducted by immunoalkaline phosphatase methods, the authors recommend addition of 50 mM tartrate to a buffer of pH 7.6-8.0. This modification does not significantly decrease the sensitivity of the specific staining of surface antigens.

Alkaline Phosphatase↗
PubMed1985

Immunohistochemical detection of monocytes by the antiserum specific to monocytic esterase.

An antiserum specific to esterase Ib was produced in a rabbit. The antigen-antibody reaction was visualized by the strong esterase activity in the precipitin band in Ouchterlony double diffusion and immunoelectrophoresis. Immunohistochemical procedure demonstrated strong staining in the monocyte-infiltrated splenic sections and tissue sections of true histiocytic lymphoma. Negative results were observed in T- and B-cell lymphomas, granulocytic sarcoma, and chronic granulocytic leukemia. This antibody may be useful for the identification of monocytes and histocytes in paraffin-embedded tissue sections.

Animals↗
PubMed1985

Simultaneous demonstration of nonspecific esterase and chloroacetate esterase in human blood cells.

A new cytochemical method is described for the simultaneous demonstration of nonspecific esterase in monocytes and chloracetate esterase in granulocytes. The procedure uses both alpha-naphthyl butyrate and naphthol AS-D chloroacetate as substrates and hexazotized pararosaniline as the coupler. The enzyme reaction products are highly chromogenic and their localization is precise. This method is potentially useful for the accurate diagnosis of the acute monocytic leukemias. Its advantages and limitations are also discussed.

Acute Disease↗
PubMed1984

Familial DiGuglielmo syndrome.

DiGuglielmo syndrome is usually considered an idiopathic disorder occurring sporadically. A family in which DiGuglielmo syndrome occurred in 4 of 11 siblings is reported. A fifth sibling has developed unexplained marrow hypoplasia. Serial morphologic and cytochemical studies, supplemented by cytogenetic studies, documented the evolution of disease. Cytogenetic and environmental investigations did not explain this clustering of blood dyscrasias although a genetic predisposition to marrow damage by environmental factors cannot be excluded. The natural history of the disease in this sibship may consist of initial reactive changes in the marrow with subsequent progression to myelodysplasia with sideroblastosis and, finally, to DiGuglielmo syndrome.

Adult↗