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Biomedical subjects

Y B Lee

Publications and source records attributed to Y B Lee.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effects of cimaterol on nitrogen retention and energy utilization in lambs.

Fifty-two weaned lambs were used in a comparative slaughter feeding trial and six lambs in a concurrent digestibility trial to investigate the effects of cimaterol on nitrogen retention and energy utilization. Cimaterol (CIM) was administered in the feed at 10 ppm for 90 and 14 d, respectively, in a comparative slaughter feeding trial and in a digestibility trial. No difference was found in dry matter digestibility. Nitrogen retention in the CIM group (739 mg/Wkg.75/d) was greater (P less than .01) than that of the control group (321 mg/Wkg.75/d). This difference was accounted for primarily by reduced nitrogen loss in urine of the CIM group. Cimaterol improved growth rate and feed/gain ratio, although these improvements were only evident during the first 42 d of the 90-d feeding trial. The improvement in growth performance of the CIM group was associated with increased protein gain in the empty body (40.2 g/d, P less than .01) as well as in carcass (26.9 g/d, P less than .01), compared with 30.1 and 14.5 g/d of the control group. Cimaterol decreased (P less than .01) fat gain (91.4 vs 109.9 g/d), total daily energy gain (1.08 vs 1.22 Mcal) and energy gain/kg gain (4.17 vs 5.11 Mcal) compared with the control. Feeding CIM increased (P less than .01) estimated fasting heat production (73 vs 64 Kcal/Wkg.75) and metabolizable energy requirement for maintenance (110.2 vs 92.7 Kcal/Wkg.75) over the control.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1989

Distribution of lymphocytic subpopulations infiltrated in thyroid glands of Graves' disease.

We studied ninety cases of thyroid glands both histopathologically and by immunohistochemical methods in patients with Graves' disease using B and T cell markers to evaluate the role of lymphocytic subpopulation. Females were affected more frequently than males with a ratio of 6.5:1, and usually the females were younger than the males at the time of surgery. The heavier the lymphocytic infiltration, the higher was the percentage of germinal center formation or fibrosis. The degree of lymphocytic infiltration was also related to the titers of antithyroglobulin or antimicrosomal antibodies. T cells were mostly scattered individually or in small groups between the follicles; however, in the severely infiltrated group, the major pattern was in clusters. T8 positive cells were more abundant than T4 positive cells, and their distribution pattern was accordant with T11 positive cells. Immunoglobulin synthesizing B cells were positively stained in 47 of 94 cases tested and IgG was the most predominant. In the mild and moderate lymphocytic infiltration groups, IgM was mostly stained at the mantle zone or in the lymphoid cluster of the interfollicular stroma, whereas IgM positive cells were present exclusively in the germinal center of the severely infiltrated group. The results of our study indicate that the major lymphocyte subpopulation in Graves' disease is B lymphocytes, and the degree of T lymphocytic infiltration correlated better with titers of antimicrosomal antibody than antithyroglobulin.

Adolescent↗
PubMed1989

Hamartoma of the urachal remnant.

A case of urachal hamartoma occurred in the urinary bladder of a 45-year-old woman, whose presenting symptoms were frequent urination and nocturia. Computed tomographic and contrast radiologic examinations demonstrated a broad-based 5-cm polypoid mass at the dome of the bladder. Grossly the polypoid mass was smooth surfaced and covered by innocent transitional epithelium. The mass and the underlying bladder wall consisted of multiple cystic cavities of various sizes and hyperplastic smooth-muscle bundles. Light microscopy identified numerous tubuloglandular structures, most of them lined by transitional cell epithelium. Simple or ciliated columnar cells and occasional mucous cells were also present, particularly in the epithelium of cystic cavities. Some tubules had communicated with the bladder lumen. Hamartoma of the urachal remnant should be included in the differential diagnosis of urachal and bladder tumors.

Female↗
PubMed1988

Sarcomere length in normal and dystrophic chick muscles.

An electron microscope study of 2- and 8-week-old normal and dystrophic chickens compared sarcomere lengths in relaxed and passively extended Patagialis (PAT) muscles. Sarcomeres were measured in dystrophic muscles only in fibers which exhibited no morphological signs of degeneration. Sarcomere lengths were not different from each other in normal muscles of 2- and 8-week-old chickens. Passive extension of the normal wing increased mean sarcomere length by 44%. Sarcomere lengths in unstretched dystrophic PAT muscles were 22 and 25% longer than unstretched normal sarcomeres at 2 and 8 weeks of age. Passive extension of the wing further increased sarcomere length of 2-week-old dystrophic muscles to the length of stretched sarcomeres in 2-week-old normal muscles. In 8-week-old dystrophic chickens, the wings could be passively extended to only 134 degrees, rather than the normal range of 180 degrees. In this case, passive extension of the wings did not further increase the length of sarcomeres. Increased sarcomere lengths in dystrophic muscles may indicate that dystrophic muscle fibers are being subjected to greater degrees of passive tension than normal muscle fibers during early stages of growth. Passive tension is known to promote fiber hypertrophy, nuclear proliferation, and increased oxidative metabolism in normal muscle. These responses to passive tension are also characteristic of prenecrotic stages of muscular dystrophy in chickens.

Animals↗
PubMed1988

Passive stretch of adult chicken muscle produces a myopathy remarkably similar to hereditary muscular dystrophy.

The wings of 10 chickens between 1 and 5 years of age were passively extended. An increase in plasma creatine phosphokinase activity was observed in 30 min, continued to rise for 24 h, and then declined, suggesting mechanically induced damage to muscle fibers. Wing muscles were removed and examined histologically at various times after stretch. Patagialis muscles, but not biceps brachii, showed the development of muscle fiber pathology. The patagialis muscle is less active than the biceps brachii and is stretched to a greater degree by wing extension. Susceptibility of muscles to development of pathology appeared to be correlated with the age of the chickens. Pathology was remarkably similar to that observed in young chickens with hereditary muscular dystrophy. Necrotic fibers exhibiting segmental necrosis, abnormal shapes, enlargement, splitting, vacuolation, and phagocytosis were evident. Of particular interest was the appearance of abnormal clusters of acetylcholinesterase activity along the sarcolemma. These sites were shown to appear on fibers of 2-week-old dystrophic chicks prior to necrosis and increase in plasma creatine phosphokinase activity. It is suggested that aging of inactive muscles may promote adhesions between muscle fibers rendering them susceptible to damage when stretched and that necrosis of dystrophic fibers may be initiated by a similar mechanism. Such could occur if the genetic defect resulted in interfiber adhesions. Support for this hypothesis by other reports in the literature is discussed.

Animals↗
PubMed1988

Cimaterol-induced growth in rats: growth pattern and biochemical characteristics.

Sixty Sprague-Dawley female rats weighing 170 g were used to investigate the effect of cimaterol on the growth pattern and biochemical characteristics of skeletal muscles. Cimaterol (CIM) was mixed in a powdered rat chow at 10 ppm. A significant (P less than .01) improvement in the weight gain of CIM group was observed during the first 8 days of the 49-day trial period, followed by no significant improvement thereafter. When CIM was withdrawn from the diet, treated rats lost weight, eventually regressing to the same weight as control rats after 28 days. CIM-fed rats showed 28.6% (P less than .01) and 12.9% (P less than .05) increases in plantaris muscle weight over the control at 8 and 14 d, respectively. DNA concentration significantly (P less than .05) decreased, whereas RNA concentration increased at 3 d (31%) and 8 d (12.7%), but decreased at 14 d compared to the control. The increase in RNA concentration preceded the significant improvement of muscle weight in the CIM group. In the soleus muscle, there was no significant difference in muscle weight or DNA concentration between the control and CIM groups. Cimaterol-feeding significantly (P less than .05) increased the size of both type I and II fibers. The size increase of type II fibers in plantaris was twice that of type I fibers in soleus (34.2% vs 17.5%). This may explain why the plantaris muscle (type II predominant) showed a greater weight increase than the soleus muscle (type I predominant).

Animals↗
PubMed1987

Adjuvant treatment of operable stomach cancer with polyadenylic.polyuridylic acid in addition to chemotherapeutic agents. Differential effect on natural killer cell and antibody-dependent cellular cytotoxicity.

Peripheral blood lymphocytes of operable stomach cancer patients were evaluated sequentially for their natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities before and after chemotherapy in association with polyadenylic.polyuridylic acid [poly(A).poly(U)]. Their cytotoxicity was measured by 4 h-chromium release assays, using human K562 and sensitized murine L1210 cells as targets for assays of NK and ADCC respectively. The mean NK cytotoxicity of 89 patients before treatment was significantly lower than that of the 18 sex- and age-matched healthy controls, whereas assays of ADCC showed similar levels of cytotoxicity in both groups. Patients who had received postoperative chemotherapy (5 fluorouracil, 12 mg/kg and adriamycin, 40 mg/M2) once, had, 5 days after injection, NK cytotoxicity levels similar to those before treatment. For these patients, an additional administration of poly(A).poly(U) (100 mg) resulted, 2 days later, in a significant increase in the levels of NK cytotoxicity without affecting the levels of ADCC. Repeated injections of poly(A).poly(U) alternated with chemotherapy induced, consistently, exclusive enhancement of NK activity after each injection. These results suggest that the effector cells for NK and ADCC activities are of functionally different cell populations.

Adult↗
PubMed1987

Effect of the repartitioning agent cimaterol on growth, carcass and skeletal muscle characteristics in lambs.

Ten crossbred (Suffolk X Rambouillet) whether lambs were randomly assigned to receive 0 or 10 ppm cimaterol (CIM) in a completely mixed high-concentrate diet for 8 wk. Total weight gain and feed efficiency were improved 29% (P less than .05) and 14%, respectively, in the CIM-fed group. CIM also improved (P less than .01) dressing percent by 4.9 percentage points and improved yield grade by one grade. CIM increased longissimus muscle (LD) area 38% (P less than .01) and the yield of four lean cuts 28% (P less than .01). No difference was found in the proportion of type I (slow-contracting, oxidative) and type II (fast-contracting, mixed glycolytic/oxidative) fibers in LD and semitendinosus (ST) muscles between control and CIM groups, indicating no change in fiber type. The cross-sectional area of type II fibers in LD and ST muscles of the CIM group was 2,081 and 1,951 micron 2 as compared with 1,391 and 1,296 micron2 of the control group, respectively. The increase was approximately 50% (P less than .01). No difference was found in cross-sectional area of type I fibers, indicating that the increase of muscle mass was due to hypertrophy of type II fibers only. DNA concentration (micrograms/g wet muscle or microgram/g protein) of CIM muscle was much lower (P less than .01) than that of control muscle, suggesting that the protein accretion in muscle was accomplished without additional incorporation of nuclei from satellite cells.

Adrenergic beta-Agonists↗
PubMed1986

Proteolytic enzyme activities and onset of muscular dystrophy in the chick.

The relationship between proteolytic enzyme activities, soluble protein profiles, and progression of pathology in dystrophic chick muscle was investigated. Activities of cathepsins C and H, and calcium-activated protease were significantly higher in dystrophic patagialis and pectoralis muscles compared with normal muscles prior to the onset of extensive muscle fiber necrosis. Proteolytic enzyme activity of dystrophic muscle remained constant relative to normal muscle during development while muscle pathology progressed in both patagialis and pectoralis muscles. There were more protein bands (60-80 kDa) in the dystrophic muscle extracts compared with normal at all ages studied. Activities of calcium-activated protease in the dystrophic pectoralis and patagialis were similar although muscle pathology progressed much more rapidly in the dystrophic pectoralis. We conclude there is no causal relationship between the activity of the above proteolytic enzymes and the development of muscle fiber necrosis. The elevated activities of proteolytic enzymes in dystrophic muscle may be due to abnormally accelerated growth.

Animals↗
PubMed1985

Stretch-induced growth in chicken wing muscles: role of soluble growth-promoting factors.

The involvement of soluble growth-promoting factors in stretch-induced hypertrophy of the Patagialis muscle (PAT) in the chicken wing was investigated. Soluble extracts were prepared from young chicken PAT muscles made hypertrophic by passive stretch and from unstretched contralateral controls. Extracts were tested for their ability to stimulate cell proliferation and creatine phosphokinase (CPK) activity in primary monolayer cultures of chick embryo muscle cells. Factors were present in muscle extracts which showed a dose-dependent stimulation of cell proliferation and CPK activity in vitro. Passive stretch for 5 days produced a rapid hypertrophy of the PAT which was accompanied by a dramatic increase in the activity of the growth factor(s). Release of stretch resulted in an arrest of growth and an immediate fall in growth factor activity. The difference in growth-stimulating activity between control and stretched PAT extracts could be demonstrated in chicken transferrin-sensitive chick myoblast cultures. Stretch thus induces an increase in a class-specific growth factor, possibly Transferrin, in the PAT. Stretched PAT extracts stimulated: (a) chick myoblast proliferation to a greater extent than an optimum concentration of chick embryo extract, and (b) CPK activity in vitro to a greater extent than excess Transferrin. Both control and stretched PAT extracts supported the growth of rat myoblasts. We conclude that PAT muscle extracts also contain unknown growth factor(s) which are different from Transferrin.

Animals↗
PubMed1984

Effects of stretch and denervation on protease activities of normal and dystrophic chicken muscle.

Changes of protease activities that follow passive stretch, denervation, and denervation plus stretch were followed in the patagialis muscle of normal and dystrophic chicks between 6 and 7 weeks of age. The baseline activities of cathepsin C, cathepsin D, and leucine aminopeptidase in dystrophic muscle were 2 to 3.5 times higher than in normal muscle. Passive stretch and denervation induced increases in protease activities by 40 to 120% in normal muscle, whereas the same treatments did not significantly affect the activities of the enzymes in dystrophic muscle. We conclude that the level of protease activity in dystrophic chicken muscle at 6 weeks of age had already attained a maximum limit and could not be increased even by denervation. In spite of protease activities, which were not different from control dystrophic muscle, denervated dystrophic muscles lost muscle weight rapidly whether they were stretched or not. They weighed 60% less than the innervated control muscle after 7 days. Inherently high protease activities in dystrophic muscle do not vary at this age regardless of whether or not the muscle is gaining or losing weight.

Animals↗
PubMed1984

Stretch-induced growth in chicken wing muscles: nerve-muscle interaction in muscular dystrophy.

Skeletal muscle growth following denervation and denervation plus passive stretch was characterized in the patagialis muscle of normal and dystrophic chicks until 8 wk of age. In both genotypes, muscles denervated at 1 wk of age grew at reduced rates compared with contralateral control muscles whether or not they were passively stretched. Histograms of fiber size distributions as well as morphological criteria showed that passive stretch of denervated dystropic muscles substantially delayed the development of pathology. Denervation alone provided less protection. There was no evidence of fiber necrosis in any denervated dystrophic muscle, although many fibers did exhibit extreme hypertrophy and abnormal morphology. When denervated dystrophic muscles were allowed to reinnervate, growth and development of pathology was rapid. Because denervation, denervation with passive stretch, or passive stretch alone retards, but does not prevent, the development of pathology, it is concluded that dystrophy in the chick is a myogenic defect that is exacerbated by neurally mediated contractile activity.

Animals↗