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M Z Fan

Publications and source records attributed to M Z Fan.

29 records · Page 2Linked to original sources
PubMed1994

Determination of apparent ileal amino acid digestibility in pigs: effect of dietary amino acid level.

Studies were carried out to investigate the effect of dietary amino acid level on apparent ileal amino acid digestibility. Six barrows, average initial BW 35 kg, were fitted with a simple T-cannula at the distal ileum and fed six diets according to a 6 x 6 Latin square design. Six cornstarch-based diets containing six levels of CP from SBM (4, 8, 12, 16, 20, and 24% CP, respectively) were formulated. Chronic oxide was included as a digestibility marker. Each experimental period consisted of 8 d. After a 6-d adaptation period, ileal digesta were collected for 24 h during d 7 and 9 at 2-h intervals. The pigs were fed twice daily, equal amounts, at 0800 and 2000. The dietary allowance was 1,600 g/d during the first period and increased by 100 g each following period. There was a quadratic increase (P < .05) in apparent ileal amino acid digestibility as the dietary CP content was increased from 4 to 24%. Initially, the apparent ileal amino acid digestibilities increased sharply then gradually reached their plateaus, after which there were no further increases and the digestibility values became independent of the dietary amino acid levels. The lower end points of 95% confidence intervals of the plateau ileal digestibility values were defined to be the initial plateau digestibilities. The dietary CP and amino acid contents, corresponding to the initial plateau digestibility values, represent the dietary threshold levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1987

[Reactivity of monoclonal antibodies ALT-01 and ALT-04 and identification of lung cancer-associated antigens].

Two IgG1 type monoclonal antibodies ALT-01 and ALT-04 were prepared by two different immunization schedules. ALT-01 was generated by fusing murine myeloma NS-1 cells with splenocytes from a BALB/c mouse immunized by human lung squamous carcinoma cells, which were coated by antisera to mixed human lymphocytes. For preparation of ALT-04, human lung squamous carcinoma xenograft-bearing nude mice were injected I. P. with the spleen cells of normal BALB/c mice in order to acquire immunofunction. The spleen cells from these tumor-bearing nude mice were fused with NS-1 cells. Then, these hybridomas were screened and cloned for 3 times. Two antibodies were shown to recognize the surface antigen on human lung carcinoma cells and several kinds of tumor cell lines but not those on normal cell lines. ALT-01 reacted to neither human lung carcinoma tissue nor its xenograft. ALT-04 reacted to human lung carcinoma tissue, of which, reaction to adenocarcinoma was the strongest but not to various normal tissues. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis and autoradiography was used to detect the associated antigen in 35S-labeled human lung carcinoma cells. Antigens, reacting to ALT-01, show one band of Mr 38,000 but those to ALT-04 reveal two bands of Mr 48,000 and 36,000.

Animals↗
PubMed1987

[Radioimmunodetection of human lung cancer xenografts by isotope labeling monoclonal antibody ALT-04 in nude mice].

Three nude mouse models bearing the human lung cancer were established from two fresh surgical specimens and one cell line. Tumor histological structure and cell morphology were similar before and after transplantation. The monoclonal antibody ALT-04 (McAb ALT-04) against human lung cancer was labeled by 125I, 131I and 201Tl. Radioimmunodetection study showed that all the three kinds of xenografts in nude mice were specifically located by McAb ALT-04. Imaging examination confirmed the ability of isotope labeling McAb ALT-04 to detect the presence of transplanted human lung cancer tissues without the aid of background subtraction manipulations. It is suggested that McAb ALT-04 have the possibility of locating in the tumor diagnosis and guiding in the treatment.

Animals↗
PubMed1987

[Kinetic observation and analysis of the radioactivity distribution of 125I-labelled F(ab')2 fragments of monoclonal antibody against human lung cancer cells in normal mice].

Radioactivity distribution of 125I-labelled F(ab')2 fragments in 14 organs and tissues of normal mice for 11 time-phases from 0.5 hour to 7 days after injection was observed. The radioactivity-time curves of these organs and tissues were divided into three types according to their characteristics: excreting type (blood and liver), absorbing type (thyroid), absorbing-excreting type (the other organs and tissues). The organs fully perfused with blood had shorter peak-time and higher peak-value, such as heart, lung, kidney and liver. All of the peak-times were equal to or less than 2 days after injection, therefore the image taking should be kept away from this period. The excreting rate constants of slow metabolic component were similar for various organs and tissues except thyroid and brain. The brain had a low peak in the curve and small excreting rate constant. It was demonstrated that F(ab')2 fragments were able to penetrate the blood-brain barrier but absorption and excretion were slower compared with the other organs and tissues. The radioiodine was obviously concentrated in the subcutaneous tissue, which may have been the main cause of the subcutaneous tissue tumor induced by radioiodine. The radioactivity-time curve in which the peak value and inflect point existed simultaneously shows that radioactivity metabolism after injection of 125I-F(ab')2 follows three compartment models. The biological meanings corresponding to three sections of the blood radioactivity-time curve are pure distribution, distribution-recycle and catabolic-excretory phases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Polyamine metabolism in McCoy cells: I. Comparative studies of extracellular polyamine conjugated proteins of human fibroblast and McCoy cultures.

polyamine conjugated proteins were identified in culture medium from both human skin fibroblasts and transformed mouse cells (McCoy cells). Sephadex G-100 column chromatography of medium allowed identification of two polyamine conjugated proteins from both types of cell cultures; one with Mr greater than 100,000 (MP1) and one with Mr = 60,000-70,000 (MP2). Human skin fibroblast MP1 contained putrescine and spermidine while MP1 from McCoy cultures contained putrescine, spermidine and spermine. MP2 isolated from both cultures contained all three polyamines. The relative concentration of polyamines in MP1 and MP2 for human fibroblasts and McCoy cells were different. The spermidine and spermine associated with MP1 and MP2 of McCoy cultures was covalently bound while for putrescine only 70.5% in MP1 and MP2 of McCoy cultures was covalently bound while for putrescine only 70.5% in MP1 and 74.5% in MP2 was covalently bound. The covalent nature of the polyamine protein conjugation was confirmed by autoradiography following isogel agarose isoelectric focusing. MP2 was resolved into three radiolabeled proteins with pI's between 5.25 and 5.20. Both MP1 and MP2 of McCoy cultures were heterogeneous. MP1 consisted of at least five proteins with Mr's of 180,000, 38,000, 76,000 and 68,000. The major protein (or proteins) had a pI of 5.25. MP2 consisted of at least three proteins with Mr's 72,000, 68,000 and 62,000; their pI's were between 5.20 and 5.25.

Cells, Cultured↗
PubMed1983

Polyamine metabolism in McCoy cells: II. Cellular origin of excreted polyamine conjugated proteins.

Incubation of McCoy cultures with medium containing 14C-putrescine resulted in the incorporation of 14C-polyamine into intracellular proteins. A greater than 100,000 dalton 14C-polyamine conjugated protein was present in the McCoy cell lysate supernatant (CLSP). CLSP was heterogeneous containing proteins with pIs ranging from 4.55 to 5.50. The major proteins had pIs of 4.55 and 5.20. Electrophoresis of solubilized McCoy cell lysate pellet revealed a 14C-polyamine conjugated protein peak with Mr approximately or equal to 70,000 (CLPP). Both CLSP and CLPP contained bound polyamine. The major CLSP polyamine was spermidine while spermine exceeded the other two polyamines (putrescine and spermidine) in CLPP. About 25% of the polyamines associated with CLSP and CLPP were covalently bound with the exception of CLSP putrescine where 62.1% was covalently bound. Results suggested the presence of a polyamine protein isopeptide bond in CLSP. Sephadex gel filtration of cultured medium resulted in the identification of two macromolecular polyamine-containing fractions (MP1, Mr greater than 100,000 and MP2, M = 60,000-70,000). Antibody raised in rabbits against a membrane-organelle preparation cross-reacted with Sephadex gel filtration derived MP1 but not with peak MP2 suggesting that MP1 but not MP2 might be a membrane constituent. Antibody raised against medium polyamine conjugated protein peak 2 (MP2) cross-reacted with the cell lysate supernatant indicating that MP2 was present in the cytosol. It did not cross-react with the cell lysate pellet preparation. Antibody against MP2 also formed a precipitation band with MP1 indicating that there might be a common antigenic site on MP1 and MP2.

Cell Compartmentation↗
PubMed1983

Polyamine metabolism in McCoy cells: III. Comparative studies of the metabolic fate of exogenous putrescine in human fibroblasts and McCoy cultures.

The fate of exogenously added 14C-putrescine following incubation for 24 hours with McCoy and human skin fibroblast cultures was examined. The nature of the polyamine derivatives found were quite different indicative of a difference in the cellular metabolism of polyamines. Exogenously added putrescine (PUT) was metabolized by both McCoy and human skin fibroblast cultures to form spermidine (SPD), spermine (SPM), gamma-aminobutyric acid (GABA) and some unidentified compounds. Within the experimental period of observation, human cultured fibroblasts metabolized PUT more efficiently than McCoy cells and converted more than 50% of it into SPD, SPM, GABA and unknown compounds. Monoacetyl putrescine (MAP) was formed by human skin fibroblasts. It was mainly identified in the culture medium. No MAP was detectable either intracellularly or extracellularly in McCoy cultures. The percentage of 14C-radioactivity found as PUT in the culture medium was greater in McCoy cells (86.0%) than in human fibroblasts (53.9%). The reverse was true for the percentage distribution of 14C-radioactivity as PUT inside the cells. No low Mr conjugates of SPD or SPM were found in the medium or intracellularly with either culture type. Some low Mr putrescine conjugates were found in the culture media; these were identified by the liberation of PUT upon acid hydrolysis.

Cell Compartmentation↗