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K W Lam

Publications and source records attributed to K W Lam.

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↗
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

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

Clinical applicability of acid phosphatase isoenzyme assay.

We compared electrophoretic evaluation of acid phosphatase isoenzymes with spectrophotometric determination of prostatic acid phosphatase in terms of clinical utility. In all of 33 cases of prostatic carcinoma, an increased prostatic fraction was detected; in nine prostatectomized patients, this fraction returned to normal as measured by either technique. Abnormal spectrophotometric results were also seen in 10 cases of benign prostatic hypertrophy and seven cases of non-prostatic disorders, but only two benign prostatic hypertrophy and one non-prostatic case showed a prostatic band (band 2) in an electrophoretogram. Band 2 was not demonstrated in 463 patients affected by a great variety of diseases but without prostatic disorders. A weak band 5 was seen in patterns for most patients, except for cases with metastatic bone tumor and Gaucher's disease, whose serum showed a strong band 5. The specificity of bands 2 and 5 seems to be confirmed by this large series of patients. Measurement of acid phosphatase isoenzymes is recommended as a routine screening test for patients whose serum acid phosphatase is abnormally high, because the isoenzyme study not only indicates the presence or absence of prostatic cancer but also whether or not there is bony metastasis. Other disorders such as Gaucher's disease, different kinds of leukemias, and thrombocythemia may also be detected and distinguished by this screening technique.

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

Lipoproteins in human subretinal fluids.

The lipids in the subretinal fluid of rhegmatogenous retinal detachment are observed mainly in the albumin position following electrophoresis on agarose film. The lipoprotein in the subchoroidal fluid of the same eye is alpha-lipoprotein. The albumin-like lipoprotein in subretinal fluid has no reaction with the antiserum samples specific to alpha-lipoprotein and beta-lipoprotein. Instead, an apoprotein of serum alpha-lipoprotein with slow electrophoretic mobility was observed in subretinal fluid. Heterogeneous degradation products of serum lipoproteins were seen in the subretinal fluid of exudative retinitis, different from the subretinal fluid of rhegmatogenous retinal detachment and uveal effusion.

Apoproteins↗
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

The effect of optic nerve transection upon the hypotensive action of ascorbate and mannitol.

Some investigators have suggested that osmolarity agents act on a central neural regulation mechanism rather than producing a direct local effect on the ocular hemodynamics. In this study, a small dose of ascorbate (.15 gm/kg, IV injection) was given to rabbits following unilateral optic nerve transection. The intraocular pressure of both eyes was significantly reduced within 5 minutes with a maximum drop at 10 minutes. When mannitol was given (0.3 gm/kg, intravenous infusion), maximal reduction of intraocular pressure occurred at 30 to 50 minutes in both eyes. In this study, it appears that optic nerve transection did not abolish the ocular response to the hypotensive action of either ascorbate or mannitol. On the contrary, the hypotensive effect of ascorbate was stronger in the experimental eye. The effective time on aqueous humor dynamics of the ascorbate occurred earlier than that of mannitol under similar experimental situations.

Animals↗
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↗
PubMed1978

An enzyme histochemical analysis of human subretinal fluid.

During rhegmatogenous retinal detachment, two major phagocytic cell populations can be identified in the subretinal fluid. Routine light and electron microscopic studies may be inadequate to assess quantitatively the free-floating retinal pigment epithelial cells and the macrophagic retinal pigment-laden cells. Enzyme histochemical staining permits a simple, rapid, reproducible method of identifying each cell type. This cytologic biochemical differentiation is an important tool for reexamination of the theories associated with subretinal fluid cell activity.

Body Fluids↗
PubMed1978

The insulin concentration in human ocular fluids.

We measured immunoreactive insulin concentrations in ocular fluids and serum of 19 patients. In rhegmatogenous retinal detachment patients without diabetes mellitus, the serum insulin level was 7 +/- 2 (SE) microunits/ml and the subretinal fluid insulin levels were mostly undetectable. By contrast, in rhegmatogenous retinal detachment patients with diabetes mellitus, serum insulin was 35 +/- 5 microunits/ml and the subretinal fluid always contained low but detectable amojnts of insulin. The data may suggest a small leak of insulin into the subretinal fluid of rhegmatogenous retinal detachment patients with diabetic retinopathy. In vitrectomy patients with diabetes mellitus there was no insulin in the vitreous in eight out of nine cases.

Body Fluids↗
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↗
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

Aqueous humor ascorbate concentration and open-angle glaucoma.

The mean value for aqueous concentration in 35 patients with open-angle glaucoma was 22.4 +/- 12.9 mg/100 ml. The mean value for aqueous ascorbate in four patients with uncomplicated senile cataract was 11.55 +/- 3.01 mg/100 ml. The results indicate that the majority of open-angle glaucomatous eyes do not involve a deficiency of ascorbate, and suggest that ascorbate has no therapeutic value in the management of primary open-angle glaucoma. The magnitude of aqueous ascorbate variation among glaucoma eyes is probably related to the factors that influence the patency of trabecular meshwork, not the metabolic activity of the ciliary processes.

Animals↗
PubMed1977

Biochemical characterization of the tartrate-resistant acid phosphatase of human spleen with leukemic reticuloendotheliosis as a pyrophosphatase.

A tartrate-resistant acid phosphatase was isolated from a human leukemic spleen by freeze-thawing in saline and purified by repeated chromatography on carboxymethyl-cellulose. The purified enzyme has a molecular weight of 64 000. It catalyzes the hydrolysis of inorganic and organic pyrophosphate as well as the phenolic ester of monoorthophosphate, with optimal activity between pH 5 and 6. However, there is no activity toward mono-orthophosphate esters of aliphatic alcohols. The present data have identified its catalytic function as a pyrophosphatase. However, it has properties different from the pyrophosphatase previously observed in normal animal tissues.

Acid Phosphatase↗
PubMed1976

Studies of intracellular distribution of acid phosphatase 5 in the spleen cells of leukemic reticuloendotheliosis by isopycnic gradient centrifugation.

A fresh spleen sample obtained from a patient with leukemic reticuloendotheliosis was homogenized and subjected to centrifugation on a sucrose density gradient. A major portion of acid phosphatase band 5 was observed in the lysosome, confirming that the elevated phosphatase activity in the neoplastic spleen is a lysosomal enzyme. However, a significant amount of brand 5 was also observed in the microsome. The microsomal and lysosomal enzymes have different affinity to CM-cellulose. The relationship between lysosomal and microsomal enzymes has not been established.

Acid Phosphatase↗
PubMed1976

Aqueous ascorbate concentration in hereditary buphthalmic rabbits.

Some aqueous humor constituents, including ascorbate, protein, and sodium, potassium, and calcium ions, were analyzed in three groups of adult buphthalmic (bu/bu) rabbits from strain AXBU/J and in control rabbits of the closely related strain AX/J. Aqueous humor ascorbate concentration of the normal strain was 22.5/"2.3mg/100ml. The buphthalmic rabbits that had no meaningful clinical signs of glaucoma at the time of sample collection had lower values (11.7/"1.7mg/100ml). Much lower values were observed in the bu/bu mutant rabbits that showed mild to severe glaucoma: 8.9/"3.8mg/100 ml and 1.9"/0.4mg/100ml, respectively. It was concluded that reduction of aqueous ascorbate is a biochemical change associated with the pathological development of buphthalmia in rabbits of the AXBU/J strain. However, the exact mechanism is still unclear.

Animals↗