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Biomedical subjects

L T Yam

Publications and source records attributed to L T Yam.

At least 109 records · Page 6Linked to original sources
PubMed1980

Basophilic leukemia.

We have described a patient with basophilic leukemia secondary to chronic granulocytic leukemia. Symptoms of hyperhistaminemia were aggravated after chemotherapy with hydroxyurea. Antihistamines (H1 receptor antagonists) controlled many of the symptoms related to hyperhistaminemia. Peptic ulcer disease with hemorrhage, however, is not controlled by H1 receptor blockade and was one of the contributing causes of death. Attempts to purify the leukemic basophils for chemical analysis met with only partial success. In treating patients with basophilic leukemia, supportive therapy for peptic ulcer disease as well as the use of cimetidine for gastric hyper acidity should be used routinely to avoid this potential complication of cytotoxic chemotherapy.

Basophils↗
PubMed1980

Immunological and biochemical evidence for identity of tartrate-resistant isoenzymes of acid phosphatases from human serum and tissues.

We purified acid phosphatase isoenzyme 5b from a human spleen affected by leukemic reticuloendotheliosis and used it to produce a specific antiserum. The antiserum was used to show complete immunological identity among isoenzymes 5a and 5b in human serum, and 5b isolated from a giant-cell bone tumor and from the spleen of a case of Hodgkin's disease. Acid phosphatase 5b in a giant-cell bone tumor was isolated for biochemical characterization. Its pH optimum and substrate specificity were very similar to those of isoenzyme 5b from human spleen.

Acid Phosphatase↗
PubMed1980

Antigenic and molecular relationship of human prostatic acid phosphatase isoenzymes.

Human prostate contains two major acid phosphatase isoenzymes, 2 and 4. Isoenzyme 2 is a glycoprotein with slow electrophoretic mobility. Treatment with sialidase increases its electrophoretic mobility to approach that of isoenzyme 4 which contains no carbohydrate. The identical protein structure of isoenzyme 2 and 4 was revealed by their antigenic identity. Serum acid phosphatase isoenzyme 5 is a different protein species and has no antigenic relationship to isoenzymes 2 and 4. Our results indicate that the elevation of isoenzyme 5 in late stages of prostatic carcinoma with bone metastases is attributable to increased osteoclastic activity.

Acid Phosphatase↗
PubMed1979

Spontaneous rupture of spleen in leukemic reticuloendotheliosis.

Leukemic reticuloendotheliosis, or "hairy cell leukemia," is a neoplasm of the reticuloendothelial system. It is characterized by the presence of many "hairy cells" in blood, marrow, lymph nodes, and spleen; by anemia, leukopenia, thrombocytopenia, and often, by massive splenomegaly. Three such patients with spontaneous rupture and one patient with multiple infarctions of the spleen all had spleens which were large, congested, and diffusely infiltrated by "hairy cells." The lacerations in all three ruptured spleens were located in areas of extensive infarction. Indications for splenectomy in this disease include hypersplenism, severe cytopenia, hemodilution, splenomegaly with severe pressure symptoms, massive splenomegaly, rupture, or infarction.

Adenocarcinoma↗
PubMed1979

Metastatic carcinoma with carcinocythemia mimicking leukemia.

Carcinoma metastatic to the bone marrow may present with peripheral blood and bone marrow changes and a clinical picture difficult to distinguish from leukemia. It is important to make an accurate diagnosis since the management is different. We have described a patient with circulating primitive cells and diffuse marrow involvement by similar cells. The pathologic process may be identified without cell markers by careful attention to the pattern of distribution, as well as the cytologic features of the neoplastic cells in the bone marrow biopsy.

Biopsy↗
PubMed1979

Significance of "high" acid phosphatase activity in the serum of normal children.

Serum acid phosphatase activity in normal children (newborn to 18 years) is several fold that in normal adults. Activity is age-related but not sex-related. The isoenzyme pattern in children is similar to that in adults and contains no prostatic fraction. Quantitatively, most of the enzyme activity in the serum of children is tartrate-resistant and correlates well with heat-labile fractions of alkaline phosphatase activity in serum, suggesting that the source of the higher acid phosphatase activity in children is bone. Significant tartrate-resistant acid phosphatase activity was demonstrated in the giant cells in three patients with giant-cell tumors, but not in the "osteoblasts" in six patients with osteogenic sarcomas and many other normal or abnormal tissues. This work suggests that the higher enzyme activity in the serum of children represents a normal physiological phenomenon resulting from their greater osteoclastic activity.

Acid Phosphatase↗
PubMed1979

Comparison of acid phosphatase isoenzymes of human seminal fluid, prostate, and leukocytes.

We used ion-exchange column chromatography and electrophoresis on polyacrylamide gel to compare the acid phosphatase isoenzymes of prostate and leukocytes. The major isoenzyme of the prostate is band 2A; only a trace of band 2B was observed. However, the major isoenzymes of leukocytes are band 4 and band 2B, and only a small amount of band 2A was observed. The three isoenzymes isolated from leukocytes or prostate gland react to the antiserum prepared against the aicd phosphatase isoenzyme of seminal fluid. Acid phosphatases of leukocytes other than the three isoenzymes mentioned above did not interact with the antiserum.

Acid Phosphatase↗
PubMed1979

Acute myelomonocytic leukemia: coexistent cytochemical markers for monocytes and granulocytes in the leukemic cells.

A 22-year-old man presented with mediastinal lymphoma and lymphoblastic leukemia. The leukemic cells in his blood and marrow did not stain positively with Sudan black B, peroxidase, chloroacetate esterase, or nonspecific esterase, and were considered as either lymphoblasts or stem cells. One year after the initial presentation, acute myelomonocytic leukemia developed and he died. The leukemic cells possessed the morphologic and cytochemical characteristics of both monocytes and granulocytes. This case illustrates the close ontogenetic relationship between the monocytes and the granulocytes. It also demonstrates that our present concept of acute myelomonocytic leukemia should be broadened to include cases in which the leukemic cells possess the morphologic and cytochemical characteristics of both the monocytes and the granulocytes.

Adult↗
PubMed1978

The cytochemistry of tartrate-resistant acid phosphatase. Technical considerations.

Cytochemical demonstration of tartrate-resistant acid phosphatase activity is essential for the diagnosis of leukemic reticuloendotheliosis. In order to perform this test correctly and to interpret the results propertly, it is necessary to understand the technical details of the cytochemical methods thoroughly. The method using naphthol--ASBI phosphoric acid--fast garnet GBC is recommended for this purpose, and factors crucial to the cytochemical study, such as fixation, substrate, coupler, pH and temperature of incubation buffer, counterstains, and mounting media are examined and discussed. Conventional methods for acid phosphatase in the presence and absence of L(+) tartaric acid are also critically examined. The naphthol--ASBI phosphoric acid--fast garnet GBC method is sensitive, technically simple and easily reproducible. Its reaction product is highly chromogenic and is most suitable for cytochemical demonstration of acid phosphatase and tartrate-resistant acid phosphatase activity in cytologic preparations. The naphthol--ASBI phosphoric acid--pararosaniline method is highly specific and is best for histochemical demonstration of acid phosphatase and tartrate-resistant acid phosphatase in tissue sections.

Acid Phosphatase↗
PubMed1978

Biochemical properties of tartrate-resistant acid phosphatase in serum of adults and children.

Spectrophotometry of total acid phosphatase activity in children's sera showed an average value of 22.4 +/- 2.9 and 7.4 +/- 0.8 U/liter, for the hydrolysis of p-nitrophenyl phosphate and alpha-naphthyl phosphate, respectively. Analyses of "band 5b", after electrophoresis on acrylamide gel, gave even higher values. The values for children's sera were much higher than those for sera from adults. The multiplicity of acid phosphatases in sera of children and adults was studied by electrophoresis on acrylamide gel and by chromatography on CM-Sepharose. Both methods showed the major acid phosphatase in children's sera to be an acid pyrophosphatase, band 5b. Its catalytic properties are indistinguishable from the enzyme previously isolated from the spleen of leukemic reticuloendotheliosis.

4-Nitrophenylphosphatase↗
PubMed1978

Biochemical characterization of an aryl acetic ester hydrolase isolated from human monocytes.

A carboxylic-ester hydrolase was isolated from the leukocytes of a patient with myelomonocytic leukemia. Its relative molecular mass as estimated by sucrose density-gradient sedimentation is about 70 000. The purified enzyme is specific for acetyl esters of aromatic alcohols. It is inhibited by fluoride, but insensitive to eserine or p-chloromercuriphenylsulfonate. Hydrolysis of 1-naphthyl acetate was optimal above pH 6.0; of o-nitrophenyl acetate, above 8.0. The common catalytic site for the two types of substrates on the enzyme was confirmed by competitive inhibition data.

Acetates↗
PubMed1978

Tartrate-resistant (band 5) acid phosphatase activity measured by electrophoresis on acrylamide gel.

A tartrate-resistant acid phosphatase was isolated from a huma spleen infiltrated with reticulum cells of leukemic reticuloendotheliosis. The purified enzyme was used to establish the optimal conditions for quantitative analysis of this enzyme by electrophoresis on acrylamide gel. As little as 0.1 unit of enzyme activity (or 1 ng of the purified enzyme protein) could be quantitatively detected when it was mixed with 4 mg of albumin before electrophoresis.

Acid Phosphatase↗
PubMed1977

Kinetic properties of tartrate-resistant acid phosphatase isolated from human spleen with leukemic reticuloendotheliosis.

The tartrate-resistant acid phosphatase was isolated from the spleen of a patient with leukemic reticuloendotheliosis. The unique characteristic of the enzyme is its similar reactivity toward p-nitrophenylphosphate, inorganic pyrophosphate ADP, and ATP. When ATP was incubated with the enzyme, the initial products were ADP and inorganic phosphate. The kinetic data confirmed that these substrates were hydrolyzed by the same enzyme. This type of substrate specificity is clearly different from acid phosphatase and pyrophosphatases previously described in the literature.

Acid Phosphatase↗
PubMed1977

Bone marrow necrosis. Diagnosis and assessment of extent of involvement by radioisotope studies.

In two patients with extensive marrow necrosis, the diagnosis of marrow necrosis was established by morphologic and radioisotopic studies, and the extent of involvement was accurately assessed by marrow scanning with technetium Tc 99m sulfur colloid while the patients were still alive. The literature on marrow necrosis was briefly reviewed and the clinical features of this condition were characterized. It was found that patients with this condition often have malignancies, underlying marrow disorders, sepsis, bone pain, and pancytopenia. Their marrow is often difficult to aspirate and they may require frequent transfusions to maintain a stable hemoglobin level. Radioisotopic studies are useful in the diagnosis and assessment of extent of involvement of this condition. They should be used in patients with clinical findings suggestive of marrow necrosis.

Bone Marrow Diseases↗