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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 721 records · Page 40Linked to original sources
PubMed1976

Liver lipid accumulation and performance of hens as affected by cage density and initial body weight.

Hens housed in individual cages (25 46 cm.) laid significantly more eggs, consumed significantly more feed and had significantly larger livers with a higher lipid content than hens housed three to a cage in two experiments. Body weight gain was significantly higher for individually housed birds in experiment 1, but not in experiment 2. No difference was observed in mean egg weight or kg. feed per dozen eggs. In experiment 2 hens housed two to a cage laid slightly fewer eggs and accumulated slightly less liver fat but the differences were not significantly different fromthose housed individually. Hens socially dominant in three bird pens had higher liver fat accumulation than hens lower on the peck order but liver fat accumulation for the dominant hens still averaged less than hens housed either two or one per cage. Comparison of two strains in experiment 1 revealed a significant difference in rate of egg production and feed efficiency but no difference in liver fat accumulation. Pullets placed in four body weight classes prior to the start of the experiment did not differ significantly in liver fat accumulation per unit of body weight or percentof dry matter of the liver at the end of the experiment. Rate of egg production and feed efficiency were also not significantly different among the body weight classes.

Animals↗
PubMed1976

Identification of a butanol-extractable human placenta-specific antigen with alkaline phosphatase activity.

N-Butanol extracts of whole-term placenta from different individuals were prepared, and used as immunogens to raise heterologous hyperimmune sera in rabbits. Upon immunoelectrophoresis the anti-placenta antisera could recognize at least six antigenic components in the placental extract even after they had been completely absorbed with pooled male serum proteins. However, the antisera so absorbed, designated (-PMS) antisera, could still react strongly with several normal adult tissue extracts including kidney. Systematic and quantitative absorptions of the (-PMS) antisera were thus further carried out with individual butanol extracts of normal adult liver, lung, intestine, stomach, kidney, bone, pancreas, spleen, heart, cerebrum, cerebellum, breast, and packed red cells, as well as a composite extract containing equal amounts of each of the 13 adult tissue extracts. Of the six antigenic components in the placental extracts reacting with the (-PMS) antisera the only one which retained its reactivity with the antisera throughout exhaustive absorptions was associated with alkaline phosphatase activity. This immunologic and enzymologic identity was confirmed with homogeneous placental alkaline phosphatase. Extracts from each of three placentae injected into three pairs of rabbits all produced an identical antibody reaction with the unique determinant(s) of placental alkaline phosphatase. The same identity of precipitin reaction was also found with extracts of 14 other placentae against each of these antisera. It thus firmly establishes that placental alkaline phosphatase is a characteristic placenta-specific fetal protein.

Absorption↗
PubMed1976

Rhabdomyoma of the heart: ultrastructural study of three cases.

The electron microscopic features of three primary cardiac rhabdomyomas were studied for the first time. Distinct striated muscle cells arranged in a disorderly fashion are described. The cases demonstrated a spectrum of possible myobibril differentiation with one case having only Z-bands and myosin filaments present while the other two had well formed thick and thin filaments with all of the bands present including Z, I, A, H, and M. Glycogen bodies, numerous mitochondria with tubular cristae, lipid deposits, and peculiar striated structures resembling zebra bodies were also seen. Desmonsomal attachments suggestive of Purkinje-type fibers were seen in all of the cases and were the only types seen in cases 2 and 3. In addition, intercalated discs characteristic of myocardial fibers were noted in case 1. This finding still leaves the exact histogenesis of the lesion uncertain although origin from two types of fibers is possible.

Heart Neoplasms↗
PubMed1975

Inefficacy of carnitine as a substitute for choline for normal reproduction in Japanese quail.

An experiment was conducted to determine if DL-carnitine could partially or completely substitute for choline for maintaining normal reproduction in Japanese quail. Adding 2800 mg. choline chloride per kg. to a purified diet significantly increased egg production and egg weight and improved hatchability, but adding a similar level of carnitine failed to improve any of the parameters measured. Likewise, performance of quail fed 1400 mg. carnitine per kg. in combination with 1400 mg. choline chloride was no better than that obtained with quail fed choline chloride (1400 mg./kg.) alone.

Animals↗
PubMed1975

A simple radioimmunoassay of human placental alkaline phosphatase (Regan isoenzyme) using specific antibody polymers.

Rabbit antiserum against highly purified high-molecular-weight B-variant of human placental alkaline phosphatase (M.W. 200,000) was rendered monospecific by absorption with polymerized pooled male serum proteins; the absorbed antiserum was then polymerized with ethyl chloroformate and used in radioimmunoassay as a stable solid-phase immunoabsorbent. Homogeneous preparation of the enzyme, with a specific activity of 477 mumoles phenol per mg per min, was also obtained by absorbing the chromatographically purified enzyme with polymerized rabbit antiserum directed to whole human serum proteins; the pure enzyme was then labeled with 125-I as the tracer retaining at least 80% of its antigenicity. Only a minute quantity of the polymerized antibody particles is required for each assay in admixture with the labeled and unlabeled enzyme. By adding a small amount of starch-gel particles before low-speed centrifugation, complete phase separation was achieved. The radioimmunoassay could detect 0.4 to 0.8 ng enzyme protein per tube, which is comparable to the sensitivity achieved by enzymic assays. However, radioimmunoassay is advantageous over the enzymic assay in being direct, specific (no interference by the nonplacental-type alkaline posphatase), and capable of detecting both catalytically active and inactive forms of the enzyme. Native variants of placental-type alkaline phosphatase including Regan isoenzyme and Nagao isoenzyme (D-phenotype of normal placental alkaline phosphatase), could thus be directly determined by this procedure in the clinical specimens.

Alkaline Phosphatase↗