Biomedical subjects

C W Kang

Publications and source records attributed to C W Kang.

At least 19 recordsLinked to original sources

PubMed2001

Expression of the insulin-like growth factors (IGFs) and the IGF-binding proteins (IGFBPs) in human gastric cancer cells.

Insulin-like growth factor (IGF)-I and -II are potent mitogens and postulated to exert autocrine, and paracrine effects on growth regulation in human gastric cancer. Their mitogenic effects are tightly regulated by the IGF binding proteins (IGFBPs). In this study, we evaluated the mRNA expression of IGF-I, IGF-II and the IGFBPs in a panel of human gastric cancer cell lines, and normal and tumour tissue specimens from patients with gastric cancer by reverse transcriptase-polymerase chain reaction (RT-PCR) and competitive PCR. Conditioned media (CM) of the gastric cancer cell lines were studied for the secretion of the IGFBPs by western ligand blot (WLB) and western immunoblot (WIB). IGF-I and IGF-II were expressed in all of the gastric cancer cell lines, and the normal and tumour tissue specimens. Overexpression of the IGFs, in particular, IGF-II, was observed in the tumour tissues. The expression pattern of IGFBPs was heterogeneous among the gastric cancer cell lines. IGFBP-2 was expressed in all of the gastric cancer cell lines, whereas IGFBP-1 was not detected in any cell lines. IGFBP-4 was expressed in the most of cell lines. IGFBP-3, IGFBP-5 and IGFBP-6 were expressed in approximately 50% of cell lines. In addition, exogenous IGF-I and IGF-II stimulated the proliferation of gastric cancer cells, suggesting the existence of a functional IGF system in gastric cancer. Taken together, our data-suggest that the IGF-IGFBP system may play an important role in the initiation, progression and metastasis of gastric cancer. Further studies are needed to understand the exact role of IGFs and IGFBPs in gastric neoplasia.

Adenocarcinoma↗

PubMed2001

L-Carnitine changes the levels of insulin-like growth factors (IGFs) and IGF binding proteins in streptozotocin-induced diabetic rat.

This study investigated the effects of L-carnitine on insulin-like growth factor-I/II (IGF-I/II) and insulin-like growth factor binding proteins (IGFBPs) in streptozotocin (STZ)-induced diabetic rats. Each rat in the three L-carnitine-treated groups was injected subcutaneously with L-carnitine, 50 (D50), 100 (D100), or 200 (D200) mg/kg body weight every other day for four weeks, and animals in normal (N) and diabetic (DM) groups received saline by the same method. Diabetic rats had significantly lower carnitine concentrations in serum and liver compared with normal rats. Total carnitine concentrations were increased dose-dependently by carnitine treatment. Total IGF-I in serum from diabetic rats was increased dose-dependently by carnitine treatment, but was statistically significant only in the D200 group. The expression of liver IGF-I mRNA was lower in diabetic rats than in normal rats and increased by L-carnitine treatment. L-Carnitine treatment of diabetic rats had no effect on the levels of IGF-II in serum, liver, and kidney. Although the levels of IGF-II in serum and kidney of diabetic rats were increased in comparison with normal rats, IGF-II mRNA was not expressed in liver. Diabetic rats had markedly lower IGFBP-3 than normal rats did, and IGFBP-3 was increased by L-carnitine treatment. These results demonstrate that L-carnitine treatment of diabetic rats modulates the IGFs/IGFBPs axis. Especially note-worthy is that L-carnitine at a dose of 200 mg/kg/48 h for four weeks was able to restore serum total IGF-I in STZ-induced diabetic rats to nearly normal levels.

Animals↗

PubMed2000

Modulation of neuroendocrinological function by psychosomatic training: acute effect of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor (IGF)-I, and insulin-like growth factor binding protein (IGFBP)-3 in men.

The neuroendocrine system is regarded as the major link between the psychological state and the immune system in man. The present study was undertaken to examine the acute effect of ChunDoSunBup Qi-training, a traditional psychosomatic training, on the plasma level of growth hormone (GH), insulin-like growth factor (IGF)-I and insulin like growth factor binding protein (IGFBP)-3 in young men. To characterize the plasma level of hormones and the pattern of IGFBP-3 at pre- (-10 min), mid-time (40 min), and immediately after (post-time, +10 min) Qi-training, radioimmunoassay (RIA) and western ligand blot (WLB) analysis were used. The plasma level of GH at the mid-time was significantly increased (P<0.05) compared to the level at pre-time of Qi-training. The plasma level of IGF-I was also increased at mid-time (P<0.05) and immediately after Qi-training. There was a significant correlation between the levels of GH and IGF-I immediately after Qi-training (r=0.69, P<0.01). In this study, the change of IGFBP-3 among the several IGFBPs was determined. There was a relative shift in IGFBP-3 for the 43-kDa fraction during mid-time of Qi-training (P<0.05). These results suggest that Qi-training influences the growth hormone, IGF-I and IGFBP-3 status via brain-target organ axis in men.

Adult↗

PubMed2000

Effects of dietary polyunsaturated fatty acid supplementation in early renal insufficiency in dogs.

Dietary supplementation with polyunsaturated fatty acids (PUFAs) alters the course of experimental kidney disease in dogs. In particular, supplementation with omega-6 PUFAs hastens the decline of kidney function, and omega-3 PUFAs are renoprotective. We investigated the early stages of renal insufficiency to determine whether PUFA supplementation altered the magnitude of hypercholesterolemia or glomerular hemodynamics. Two months after 11/12 nephrectomy, dogs were randomly divided into three groups of 6 animals each. Each group of dogs was then fed a low-fat basal diet supplemented with one of three sources of lipid to achieve a final concentration of 15% added fat. Fat sources were rich in omega-3 PUFAs (menhaden fish oil, group FO), omega-6 PUFAs (safflower oil, group SO), or saturated fatty acids (beef tallow, group C). Early in renal insufficiency, before significant kidney damage, group FO had a lower (P<.05) serum cholesterol concentration and tended to have a lower urinary prostaglandin E2 (PGE2) and thromboxane A2 (TxA2) excretion than group C. In contrast, group SO had a higher mean glomerular capillary pressure (P<.05) and more glomerular enlargement (P<.05) and tended to have higher eicosanoid excretion rates than group C. These differences in lipid metabolism, glomerular hypertension and hypertrophy, and urinary eicosanoid metabolism could explain, in part, the beneficial effects of omega-3 PUFAs and the detrimental effects of omega-6 PUFAs when administered on a long-term basis in this model of renal insufficiency.

Animals↗

PubMed1999

Effects of ChunDoSunBup Qi-training on growth hormone, insulin-like growth factor-I, and testosterone in young and elderly subjects.

We observed the response of plasma growth hormone (GH), insulin-like growth factor-I (IGF-I) and testosterone (T) to an acute period of ChunDoSunBup (CDSB) Qi-training. Although the basal level of GH was not different between the two groups, after the portion of the training in which the subjects were physically active (the mid-training point), plasma GH levels increased by 7.26 fold (p < 0.05) in the elderly trainees and by 1.66 fold (p < 0.05) in the young. In response to CDSB Qi-training, IGF-I levels in the young increased significantly at mid-training point, but there were no increase in the elderly. Significant correlations existed between GH and IGF-I levels in the young subjects, but not in the elderly. The T level at the mid-training point increased significantly in elderly subjects but not in the young. These results suggest that CDSB Qi-training is a potential method for modulating of the secretion of growth factor in the young and the elderly, but that the elderly IGF-I response does not equal that of the young. In addition, our study suggests CDSB Qi-training may be one mode of therapy applicable to growth factor related disorders such as GH deficiency in children and osteoporosis in the elderly, especially women.

Aged↗

PubMed1998

Acute effects of chundosunbup qi-training on blood concentrations of TSH, calcitonin, PTH and thyroid hormones in elderly subjects.

The present study investigated how the systemic treatment of a programmed exercise, ChunDoSunBup (CDSB) Qi-training, affects the secretion of thyroid and parathyroid hormones in elderly subjects (10 male and 5 female). Plasma concentrations of thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), parathyroid hormone (PTH), ionized calcium, and calcitonin were determined. CDSB Qi-training induces a slight increase in TSH. Both T4 and T3 were increased at the mid-time of CDSB Qi-training (p < 0.05). There were significant correlations only between T3 and T4 at mid-training. This shows that increase in the plasma level of T3 was associated with the secretion of T4. The plasma concentrations of calcitonin and PTH were increased at mid-time and post-time of CDSB Qi-training. But ionized calcium was decreased slightly by CDSB Qi-training. These results suggest that Qi-training modulates the secretion of thyroid hormones, calcium metabolism, and parathyroid hormones in the elderly. However, whether the long-term practice of CDSB Qi-training might change bone metabolism and have longitudinal effects on the thyroid hormone of the elderly need further investigation.

Aged↗

PubMed1997

Serum insulin-like growth factors (IGFs) and IGF binding protein (IGFBP)-3 in patients with gastric cancer: IGFBP-3 protease activity induced by surgery.

Recent findings have indicated that insulin-like growth factors (IGF-I and IGF-II) may play a role in neoplasia. Alteration of serum IGFs or IGF Binding Proteins (IGFBPs) have been reported in some tumors. In this study, we measured serum IGF-I, IGF-II and IGFBPs profile in gastric cancer by radioimmunoassay and Western ligand blots. The serum IGF-I level in gastric cancer was significantly lower than in control subjects (65.2 +/- 26.5 vs 148.4 +/- 55.2 ng/ml, p < 0.01) and was further decreased to 45.5 +/- 20.9 ng/ml after surgery. The serum IGF-II level was slightly higher than that in control subjects (826.3 +/- 360.2 vs 735.7 +/- 154.6 ng/ml) but it was significantly decreased after surgery (525.7 +/- 220.1 ng/ml, p < 0.05). The serum IGFBP-3 level was not significantly different from those in control subjects. However, we observed a decreased level of serum IGFBP-3 after surgery, and incubation of postoperative serum with control serum resulted in a significant reduction of IGFBP-3 level. The reduction of IGFBP-3 in postoperative serum was mainly due to surgery associated IGFBP-3 protease activity. This protease activity was totally inhibited by aprotinin, EDTA and PMSF but not by pepstatin and leupeptin. This inhibition pattern is consistant with cation dependent serine protease. We speculate that proteolysis of IGFBP-3 may contribute to increase the bioavailability of IGFs.

Adenosarcoma↗

PubMed1994

Identification of immunoreactive atrial natriuretic peptide in the gallbladder and bile juice of rabbit, pig and human.

The presence of immunoreactive atrial natriuretic peptide (irANP) in rabbit, pig and human gallbladders was investigated using radioimmunoassay and immunohistochemistry. Serial dilution curves of gallbladder tissue and bile juice extracts were paralleled to the standard curve of atriopeptin III. Gel filtration profiles of gallbladder tissue extracts showed a major peak corresponding to rat pro-ANP. The amounts of irANP in rabbit, pig and human gallbladders were 30.0 +/- 12.3 pg/mg (n = 7), 7.0 +/- 2.0 fg/mg (n = 7) and 17.7 +/- 2.0 fg/mg wet tissue (n = 8), respectively. Bile juice was also shown to contain irANP but with small molecular mass. The amounts of irANP in the rabbit, pig and human bile juice were 25.0 +/- 2.0 (n = 7) and 0.50 +/- 0.02 (n = 7), and 1.3 +/- 0.1 pg/ml (n = 8), respectively. The immunohistochemical staining of the rabbit gallbladder tissue revealed the presence of irANP in the luminal epithelium and smooth muscle layer. The amount of irANP was higher in the luminal epithelium than in the rest of the gallbladder tissue from rabbits (0.30 +/- 0.06 vs. 0.01 +/- 0.01 pg/microgram protein, P < 0.01). These findings suggest that ANP may be synthesized and stored in the gallbladder, and may have a role in the regulation of fluid balance and cystic motility.

Animals↗

PubMed1994

Atrial natriuretic peptide immunoreactivity in the eggs of the silkworm Bombyx mori.

Synthesis and secretion of atrial natriuretic peptides (ANPs) are not confined to the atrium, but are also present in other tissues. Recently, we have found synthesis of ANP in the eggs of several vertebrate animals. The present study was undertaken to determine whether immunoreactive ANP (irANP) is present in the egg of an invertebrate, the silkworm (Bombyx mori L.). The serial dilution curve of egg extracts of silkworm was parallel to the standard curve of atriopeptin III. Analysis of ANP immunoreactivity by gel filtration chromatography and reverse-phase HPLC showed that the major immunoreactivity corresponded to rat proANP. The semipurified irANP of egg extracts produced a dose-dependent relaxation on rat aortic strips, which was blocked by preincubation with anti-ANP antiserum. Therefore, we suggest that ANP is synthesized in the silkworm egg.

Animals↗

PubMed1988

Transcription initiation site selection and abortive initiation cycling of phage SP6 RNA polymerase.

Effects of mutations around the phage SP6 transcription initiation site on SP6 RNA polymerase's selection of initiation site were studied. In the in vitro transcription reactions, the limiting concentration of a ribonucleotide causes the SP6 RNA polymerase to stall long enough only at the positions of the limited nucleotide and dissociate from the elongation complex. As a result, a series of RNA oligomers comprises a sequencing ladder, and abortive initiation cycling products up to 6-mer are made in high yield. Precise sizing of the product RNAs from the elongation pausings determined the initiation site of each mutant. When the wild-type +1 G is changed to C or A without change in the upstream sequence including TATA from -4 to -1, transcription still starts only at the +1 site. But, the mutant containing TATCC from -4 to +1 C. We propose that the phage SP6 RNA polymerase selects the initiation site precisely at a certain distance from a direct contact point in the upstream promoter sequence, regardless of the species of initiating nucleotide. It is also suggested that the sequence-dependent perturbations of DNA helical structure, for example D to B form, may shift the initiation site.

Bacteriophages↗

PubMed1986

Utilization of alpha-ketoisocaproate for protein synthesis in uremic rats.

We have recently shown that the nutritional efficiency, R, of alpha-ketoisocaproate (KIC) as a substitute for leucine, defined as the ratio of the dose of leucine to the dose of KIC (on a leucine-free diet) for equal growth, can be evaluated isotopically: 14C-KIC and 3H-leucine are administered p.o.; six hours later, 14C/3H in the leucine of whole body protein, divided by 14C/3H in the injectate, gives a value distinguishable from R assessed in the same animals by growth experiments. To see how chronic uremia affects R, 11/12 nephrectomized rats and sham-operated controls were fed a regular diet for 15 days and then given these isotopes p.o. Six hours later, R, measured in whole body protein, and in the protein of brain, heart, muscle, salivary gland, liver, and the kidney remnant was significantly greater than in sham-operated controls. The greatest difference (39%) was seen in liver protein and the smallest difference (19%) in muscle. Thus chronic uremia increases the efficiency, relative to leucine, with which KIC is utilized for protein synthesis in all of these organs and in the body as a whole. Possible explanations are discussed.

Animals↗

PubMed1986

Effect of the level of dietary protein on the utilization of alpha-ketoisocaproate for protein synthesis.

The efficiency of alpha-ketoisocaproate (KIC) as a dietary substitute for leucine in rats on varying protein intake was estimated by an isotopic method, previously shown to yield the same results as comparative growth experiments. 14C-KIC and 3H-leucine are injected orally. Six hours later the ratio, R, of 14C/3H in isolated proteins, divided by the same ratio in the injectate is measured. This ratio has been shown to be approximately equal to nutritional efficiency of KIC relative to leucine. As dietary protein increased from 6.3% to 48.3%, whole body protein R decreased from 0.515 +/- 0.045 to 0.299 +/- 0.016. Variations with protein intake were noted in R of protein isolated from individual organs. The magnitude of R in these organs varied two-fold, in the following sequence: brain greater than heart greater than or equal to skeletal muscle greater than or equal to salivary gland greater than or equal to kidney greater than liver. Whole body protein R could be confidently predicted (r2 = 0.992) from R in the protein of kidney and muscle. Thus the nutritional efficiency of KIC as a dietary substitute for leucine in individual organs as well as in the whole animal is strongly dependent on the level of protein intake.

Administration, Oral↗

PubMed1985

Structure of ribosome-bound messenger RNA as revealed by enzymatic accessibility studies.

Digestion with ribonuclease T2 has been used to study the size of poly(U) protected by ribosome binding. Several different preparations of ribosomes all appear to cover 49 nucleotides of message; however, there are two partially accessible internal nuclease cleavage sites, which yield, ultimately, fragments 20, 16 and 13 nucleotides in length. Curiously, the site between fragments of length 20 and 16 is accessible to RNase T2 but not to the several much smaller RNases. Arguments based on the quantitative pattern of cleavage and comparisons with previous studies lead to the conclusion that the 20-mer is the 5' fragment, while 13-mer (which is lost the moment it is cleaved from the 16-mer) is the 3' fragment. Both ribosome-bound tRNAs appear to contact only the 16-mer. The presence of the two internal cleavage sites fits nicely with recent electron microscopic data suggesting that mRNA forms a loop around the 30 S subunit.

Chromatography, Gel↗

PubMed1985

Nutritional efficiency of alpha-ketoisocaproate relative to leucine, assessed isotopically.

The efficiency of alpha-ketoisocaproate as a dietary substitute for leucine was assessed in rats by two techniques: first, the minimal dose of alpha-ketoisocaproate required, as a supplement to a leucine-free diet, to achieve a growth rate as great as animals receiving leucine was found to be between 2.2 and 4.4 times larger. Therefore the nutritional efficiency of alpha-ketoisocaproate lies between 0.23 and 0.46. Second, alpha-[1-14C]-ketoisocaproate and [3H]leucine were administered orally and the ratio of 14C/3H incorporated into the leucine of whole-body protein and fibrin was measured. This ratio, divided by the ratio 14C/3H injected, was the same in fibrin as in whole-body protein and averaged 0.39. Thus both techniques yield the same value, within the error of measurement, for the relative nutritional efficiency of alpha-ketoisocaproate. We also found that alpha-ketoisocaproate feeding at varying dosage did not alter this ratio in whole-body protein (measured in rats fasted overnight), suggesting that neither wide variations in growth rate nor exposure for 10 days to alpha-ketoisocaproate (in a diet of constant protein content) alters the relative rates of utilization (or oxidation) of alpha-ketoisocaproate vs. leucine.

Animals↗

PubMed1985

Growth and protein turnover in the skeletal muscles of broiler chicks.

Growth and protein turnover were examined in the breast (pectoralis thoracica) and the leg (gastrocnemius-peroneus) muscles of broiler chicks at 1, 2, 4, and 6 weeks posthatching. The fractional rate of protein synthesis (ks) was measured by an isotope emulsion method. The fractional degradation rate (kd) was calculated from the difference in ks and fractional deposition rate (kg), which was estimated from regression equations of muscle size and protein content on body weights. The growth rate (%/day) of skeletal muscle exceeded that of the whole body. Muscle growth involved an increase in the total deoxyribonucleic acid (DNA) and the DNA-unit size and a subsequent decrease in the concentrations of nucleic acids without alteration in the ribonucleic acid (RNA):DNA ratio and RNA and DNA activity. The ks in breast muscle protein fell markedly from 48 to 16%/day between 1 and 6 weeks posthatching, whereas in leg muscle, ks underwent a more gradual decrease; from 36 to 17%/day during the same period. These changes resulted mainly from the reduction of DNA and RNA concentrations with age. The kd decreased only slightly between 1 and 2 weeks in the both muscle groups. The kg also showed a developmental fall from 33 to 4%/day and from 21 to 4%/day in the breast and leg muscles, respectively, during the 5-week period.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1985

Characteristics of growth and protein turnover in skeletal muscle of turkey poults.

Protein turnover and DNA and RNA levels were measured in the breast (pectoralis thoracica) and leg (gastrocnemius-peroneus) muscles of large white (Nicholas strain) turkey poults from 1 to 8 weeks of age to investigate their cellular growth and to evaluate the influence of protein turnover on muscle growth. Fractional rates of protein deposition (kg) were determined from regression equations of muscle size and protein content on body weights. Protein synthesis rates (ks) were measured by an isotope emulsion technique. Protein degradation rates (kd) were estimated by the difference between ks and kg. Muscle growth involved increases in total deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), an increase in the DNA-unit size, and decreases in concentrations of the nucleic acids without changes in the RNA:DNA ratio or RNA and DNA activity. The muscles showed developmental changes in ks from 56 to 10%/day and from 38 to 13%/day in breast and leg, respectively, over the 7-week period. The fractional degradation rate also fell from 22 to 7%/day in the breast muscle and from 21 to 10%/day in the leg muscle. The disproportionate decline of ks and kd resulted in an age-associated fall in kg from 34 to 4%/day and from 18 to 3%/day in the breast and the leg muscles, respectively. The efficiency of protein deposition decreased from 61 to 35% in breast muscle and 46 to 20% in leg muscle. The results were qualitatively similar to those obtained in a study with broiler chicks.

Aging↗

PubMed1984

Characteristics of growth and protein synthesis in skeletal muscles of normal and dystrophic chickens.

Several characteristics of cellular growth and protein synthesis were measured in vivo in the breast and leg muscles of normal (line 454) and hereditary muscular dystrophic (line 455) New Hampshire chickens at different ages. Fractional rates of protein synthesis (ks) were calculated from the rate of incorporation of labeled tyrosine administered continuously via a subcutaneous injection of an emulsion of L-[U-14C]tyrosine in sesame oil. Only the breast muscle showed signs of gross hypertrophy. The hypertrophy involved an abnormally rapid accumulation of protein, DNA and RNA. In dystrophic chickens, ks was at least 170% of the normal rates at 2, 5 and 52 weeks. The elevated ks was presumably a reflection of the higher DNA and RNA concentrations relative to those in normal birds. Because the RNA/DNA ratio and the activities of RNA and DNA were similar to values observed in normal birds, there may be no defect in the synthesis machinery per se.

Animals↗

PubMed1984

Protein degradation: an important consideration.

The growth rates of chicks can be varied by dietary manipulations. The rates of synthesis of protein in selected muscles can be measured by using radioactive amino acids. Measurements are made of expired air, plasma, and muscle tissues. Synthesis rates are most rapid in the young chick and turkey. As the bird ages, synthesis rates and degradation rates decrease; but these two parameters gradually come together so that the net gain in protein is zero. Synthesis rates remain fairly similar in chicks fed a complete diet or a diet lacking in lysine. This is true even if the growth rate is extremely low. However, the degradation rates are extremely high in the deficient birds so that the gain in protein deposition is very low. When the energy is restricted, growth is reduced dramatically, but synthesis rates are reduced only a small amount. Again, degradation rates are extremely high. Chickens with muscular dystrophy exhibit very high synthesis rates in breast muscle. The leg muscle changes compare with a normal bird. There are also high degradation rates in the breast muscle throughout so that the growth rate of the muscle was only greater during the early stages of growth. Additional work needs to be conducted to develop a reliable accurate chemical method for determining the degradation rates. It is apparent that the emphasis in research to increase the rapidity of growth should center on the degradation rates rather than on increasing synthesis rates.

Amino Acids↗