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Biomedical subjects

J R Huang

Publications and source records attributed to J R Huang.

15 recordsLinked to original sources
PubMed2005

Effects of artificial liver support system on patients with acute or chronic liver failure.

AIMS: Acute on chronic liver failure (AoCLF) is associated with a high mortality rate. Artificial liver support system (ALSS) is useful to bridge patients with liver failure to liver transplantation or to regenerate their own livers. The aims of this prospective study were to investigate the effects of ALSS on clinical manifestations, liver function, and 30-day survival to probe the factors related to mortality in patients with AoCLF. METHODS: In this study, 338 enrolled patients with AoCLF who received ALSS treatment for 1 to 8 sessions, were compared with 312 patients treated with conventional medications. RESULTS: Clinical manifestations and liver functions were significantly improved, namely, decreased levels of serum transaminases, total bilirubin, and bile acid, as well as increased levels of serum albumin following ALSS treatment. The 30-day survival rates of the patients who received ALSS versus controls were 47.9% versus 34.6%, respectively (P = .01). The MELD score and the stage of hepatic encephalopathy were highly associated with mortality (P < .001), but the sessions of ALSS showed a positive relation to the 30-day survival (P < .05). CONCLUSIONS: ALSS appears to be efficacious and safe for the treatment of patients with AoCLF. Both model for end-stage liver disease (MELD) score and hepatic encephalopathy are useful to predict the mortality of patients.

Adolescent↗
PubMed2001

[A study of artemether combined with primaquine in the treatment of falciparum malaria].

OBJECTIVE: To evaluate the efficacy and side effects of artemether combined with primaquine in the treatment of falciparum malaria. METHODS: Randomization and comparison methods were used in 121 falciparum malaria cases in the Republic of Central Africa. Sixty-one cases were treated with artemether combined with primaquine (Group A used artemether orally, Group B used artemether intramuscularly). And 60 cases received single artemether (Group C used artemether orally, Group D used artemether intramuscularly) were taken as control. RESULTS: In Group A and B the mean fever clearance time were 47.6 +/- 15.7 and 36.9 +/- 10.7 hours, clinical cure rates 84.4% and 100%, relapse rates 6.3% and 3.4%, respectively. In Group C and D the mean fever clearance time were 48.2 +/- 18.4 and 42.2 +/- 9.5 hours, clinical cure rates 90.1% and 96.3%, relapse rates 21.2% and 18.5%, respectively. Side effects in cases of all groups were mild. CONCLUSION: Artemether combined with primaquine and single artemether(via both routes) showed good therapeutic effects in falciparum malaria cases, while artemether combined with primaquine was more effective than single artemether in reducing relapes rate of malaria.

Adolescent↗
PubMed1992

Progestin stimulates the biosynthesis of fibronectin and accumulation of fibronectin mRNA in human endometrial stromal cells.

Fibronectin is a major component of decidual basement membrane. In the present study, we have investigated the effect of progestin on the synthesis and secretion of fibronectin in human endometrial stromal cells. Stromal cells were isolated during the menstrual cycle and cultured in RPMI-1640 with 2% fetal calf serum supplemented with progesterone or medroxyprogesterone acetate (MPA) in a long-term culture system. Indirect immunofluorescent staining showed that fibronectin was uniformly distributed in the intracellular and extracellular regions of stromal cells treated with MPA for 14 days. The biosynthesis and secretion of this protein and the accumulation of cellular fibronectin mRNA were studied after various culture periods. Cells were pulse-labelled with [35S]methionine to determine the amount of newly synthesized fibronectin secreted into the culture medium. A monoclonal antibody (Mab) identified human fibronectin on SDS-polyacrylamide gel electrophoresis (SDS-PAGE), showing a predominant band (Mr 230-250 kDa) which migrated with authentic fibronectin run in parallel. In six endometrial specimens, the amount of radioactivity incorporated as [35S]fibronectin was increased by progestin. Maximal stimulation occurred after 6 days treatment with MPA. Culture beyond 16 days reduced the rate of synthesis and secretion to 40% of the maximum. The effect of progestin was dose dependent with 0.02, 0.2 and 1 microM progesterone, producing 2.0, 3.8 and 11-fold increases respectively, over the control. Medroxyprogesterone acetate was more effective than progesterone, the maximal response (10-fold increase) being achieved at 0.02 microM MPA.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1991

Fluorescence changes of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole bound to thiol groups of gizzard myosin.

The fluorescence intensity of gizzard myosin that incorporated about 2 mol of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-C1) at 0.6 M KC1 was quenched at low concentrations of MgATP or in the presence of F-actin. The observed quenching was reduced at high MgATP concentrations. The half maximal change in quenched fluorescence was shifted from 7.5 microM to 25 microM MgATP for NBD-myosin at 0.15 M KC1. The fluorescent label NBD-C1 can be used to detect changes in the conformation of gizzard myosin.

4-Chloro-7-nitrobenzofurazan↗
PubMed1990

Reaction of thiol groups of gizzard myosin heavy chains with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole.

Chicken gizzard myosin treated with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) resulted in a 65% inhibition of the K(+)-ATPase (myosin ATP phosphohydrolase (actin translocating), EC 3.6.1.32) activity and 3.5 mol of the reagent was bound per 4.7 x 10(5) g protein. The labeling was limited to the heavy chain region and none of the light chains were lost. MgATP had no effect on the inactivation or labeling pattern. Thiolysis of NBD-myosin with dithiothreitol restored the K(+)-ATPase activity and concurrently, 1 mol of the NBD group was removed from the heavy chain region. Cysteine residues were modified in NBD-myosin at sites other than the active site when the enzyme activity was inhibited. There was a difference in the extent of NBD-Cl modification of gizzard myosin at 0.6 M KCl (6 S elongated state) when compared to that at 0.15 M KCl (10 S folded state). This was also seen in the heavy meromyosin-like chymotryptic fragments and tryptic fragments of NBD-myosin. The reagent NBD-Cl can detect changes in the conformation of gizzard myosin by way of its reaction with thiol groups of the heavy chain region.

4-Chloro-7-nitrobenzofurazan↗
PubMed1990

Fluorescence properties of the Ca2+,Mg2(+)-ATPase protein of sarcoplasmic reticulum labeled with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole.

The fluorescence intensity of the Ca2+,Mg2(+)-ATPase protein of rabbit skeletal sarcoplasmic reticulum that incorporated about 2 mol of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) was enhanced at high MgATP concentrations with or without 50 microM calcium. The observed enhancement indicates that the fluorophore, NBD-Cl, can detect conformational changes in the ATPase protein.

4-Chloro-7-nitrobenzofurazan↗
PubMed1990

Differential effects of progestin and relaxin on the synthesis and secretion of immunoreactive prolactin in long term culture of human endometrial stromal cells.

PRL secretion from human endometrium is a continuous process extending from the luteal phase of the menstrual cycle throughout the entire gestational stage. We have developed a long term primary cell culture system to elucidate the hormonal requirements for this sustained production of PRL. The effects of medroxyprogesterone acetate (MPA), progesterone, and relaxin (RLX) on the production of immunoreactive PRL were investigated. MPA stimulated cell growth and PRL production rate during days 5-20 of culture. Progesterone was 20-40% less effective in stimulating PRL than MPA. Stimulation of PRL was continued 1-2 weeks after MPA withdrawal. Relaxin did not promote cell growth. However, it induced the PRL production which fluctuated during the long term culture. The maximal response to RLX was 2- to 3-fold higher or similar to that of MPA. Only five of nine endometrial specimens examined responded to RLX alone. The effect of MPA plus RLX was significantly greater than that of MPA or RLX alone. The highest production rate was shown in cells treated with MPA and then RLX in sequence. After a month of culture, the production rates (micrograms of PRL per 0.1 mg cell DNA/day) under various culture conditions (A, control; B, MPA; C, MPA for 10-15 days and no hormone afterward; D, both MPA and RLX; and E, MPA and RLX in sequence) were: A, about 0-0.01 (n = 12); B, 2.5 +/- 0.9 (n = 8); C, 4.8 +/- 2.5 (n = 8); D, 5.7 +/- 3.0 (n = 5); and E, 11 +/- 3.7 (n = 7); mean +/- SD; n, number of specimens). Endometrial stromal cells were incubated with [35S]methionine, and [35S]immunoreactive PRL and other secretory proteins were analyzed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis to characterize the size and isoforms of immunoreactive PRL. PRL was one of the five major secretory proteins (23-25K, 32K, 42K, 78K, and 150K daltons, sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing condition) induced by MPA and RLX in endometrial stromal cells. More than 90% of immunoreactive PRL was secreted into the medium. The apparent mol wt of immunoreactive PRL were 21K, 23K (the predominant size), and 25K daltons. Results obtained from the incorporation of [14C]glucosamine into immunoreactive PRL indicated that both 23K and 25K PRL contained glycosylated PRL. A 45K-dalton glycosylated immunoreactive PRL was also present in the culture medium.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Modification of the (Ca2+ + Mg2+)-ATPase protein of sarcoplasmic reticulum with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole.

The (Ca2+ + Mg2+)-ATPase (ATP phosphohydrolase (Ca2+-transporting), EC 3.6.1.38) protein of rabbit skeletal sarcoplasmic reticulum (SR) rapidly incorporated 2 mol of 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) per 10(5) g of protein with little change in the Ca2+-dependent ATPase activity. When 2 additional mol of the reagent were bound the Ca2+-ATPase, activity was inhibited. The same pattern was found for modified intact SR and the Ca2+ uptake ability was inhibited. MgATP, CaATP and MgADP protected the Ca2+-ATPase activity concurrent with a decrease of about 1 mol of the NBD group per 10(5) g protein, but the Ca2+ uptake ability was not protected. Calcium alone had no effect on the modification. The modified ATPase protein or SR formed non-serial oligomers or aggregates, but the ATPase protein remained the predominant species present. In the presence of MgATP, oligomer formation was reduced partially but the major changes in the Ca2+-ATPase activity were due to the modification of the ATPase monomer. Thiolysis of the NBD-ATPase protein with dithiothreitol did not restore the Ca2+-ATPase activity, although more than 1 mol of the NBD group was removed from cysteine residues. Cysteine residues were modified in the NBD-ATPase protein or SR when the enzyme activity was inhibited. Trypsin digestion of NBD-SR or its ATPase protein released the A, B, A1, and A2 fragments. The A fragment and its subfragment A2 contained most of the label. Substrate MgATP protection studies showed that the A1 and A2 fragments were involved in maintaining the Ca2+-ATPase activity. Reagent-induced conformational changes of these fragments rather than direct active site group labeling accounted for the loss of ATPase activity.

4-Chloro-7-nitrobenzofurazan↗
PubMed1989

Immunologic identification of the aromatase enzyme system in human endometrium.

Confluent human endometrial stromal cells were cultured in medium with no hormone or supplemented with medroxyprogesterone acetate (MPA), estradiol (E2), and porcine relaxin (RLX) for 5 days. These stromal cells were then labeled with [35S]methionine for 3 h. The radioactive proteins in the particulate fraction of cell homogenate were extracted by detergent and incubated with antisera to purified placental aromatase cytochrome P-450 (P-450arom) and NADPH-cytochrome P-450 reductase to isolate the radio-labeled aromatase enzyme components. Analysis of the radio-labeled protein, isolated by antibody to the cytochrome P-450arom from different preparations (P45FBIII or R-8-2) showed a major band at molecular weight 54k on SDS polyacrylamide gel electrophoresis (SDS-PAGE). The intensity of 54k band was stronger in hormone treated stromal cells than that of control in parallel with the increase of aromatase activity. The radio-labeled protein isolated by anti-NADPH cytochrome P-450 reductase, REDFBIV, showed a major band at the molecular weight 73k on SDS-PAGE with comparable intensity in control and hormone treated samples. Thus, the apparent molecular weights of endometrial cytochrome P-450arom and cytochrome P-450 reductase were identical to placental aromatase enzyme system. When a secretory endometrium and a decidua were labeled with [35S]methionine, the cytochrome P-450arom was detected only in the decidua. NADPH cytochrome P-450 reductase was detected both in the endometrium and the decidua. These results show that antisera to placental aromatase enzyme system cross reacts with the endometrial aromatase enzyme components. The synthesis of cytochrome P-450arom was stimulated by MPA, E2 and RLX while the synthesis of the NADPH-cytochrome P-450 reductase aromatase component was not affected by the hormone.

Aromatase↗
PubMed1989

Long-term effects of progestin and RU 486 on prolactin production and synthesis in human endometrial stromal cells.

Previous studies have shown that the production of prolactin (PRL) is increased in human endometrial stromal cells cultured with medroxyprogesterone acetate (MPA) for 3-5 days. In the present study, we have investigated the effect of prolonged treatment of progestin and anti-progestin, RU 486, on the production and synthesis of PRL. Stromal cells were isolated from human endometrium obtained from non-pregnant women and cultured for 20-30 days in medium RPMI 1640 with 2% fetal calf serum or supplemented with MPA, RU 486, alone or in sequence. The PRL content in medium was measured by radioimmunoassay. The production rate was estimated from the PRL content in medium accumulated in 24 h. The PRL production rate was progressively increased in stromal cells continuously treated with MPA for 30 days (greater than 100-fold over the control value, i.e. 0-0.01 microgram/0.1 mg cell DNA/day). RU 486 alone had no effect on the production of PRL. However, the production of PRL was increased by MPA in stromal cells pretreated with RU 486 indicating that the effect of RU 486 is reversible. When stromal cells were treated with MPA and RU 486 sequentially, RU 486 stimulated the PRL production (approximately 2-fold over the MPA-treated cells) for 2-3 days and then reduced to basal levels over a 5-day period. The stimulatory and inhibitory effects of RU 486 on PRL production in stromal cells pretreated with progestin was also observed in the rate of synthesis of PRL estimated by incubating the stromal cells with [35S]methionine and immuno-isolating the [35S]PRL with anti-PRL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The effect of relaxin on cyclic adenosine 3',5'-monophosphate concentrations in human endometrial glandular epithelial cells.

The effects of relaxin (RLX), forskolin (Fk), and 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro, a phophodeisterase inhibitor) on the accumulation of cyclic adenosine 3',5'-monophosphate (cAMP) in human endometrial glandular epithelial cells were studied. Epithelial glands were isolated from the endometrium by digesting the viable tissue fragments with collagenase. The epithelial glands were incubated with Ro, RLX, and Fk separately or in combination. The amount of cAMP was determined at the end of incubation. A moderate increase in cAMP content was observed in epithelial glands incubated with Ro alone. Accumulation of cAMP after incubation with RLX was observed only in the presence of Ro. Increase of cAMP content in response to RLX and Ro was time- and dose-dependent. The accumulation of cAMP was apparent in 5 min, reached the maximum after 15 min, and remained elevated for 17 h incubation. One nanogram per millileter RLX was effective to increase the cAMP content, with a maximal response at 100 ng/ml. The effect of Ro and the combined effect of Ro and RLX on cAMP accumulation were studied in epithelial glands of 20 endometrial specimens obtained during different stages of the menstrual cycle. When epithelial glands were incubated with Ro alone, the cAMP concentration in glands from proliferative endometria was 120 +/- 67 pmol/mg protein (n = 6, means +/- SD), significantly higher than that of secretory endometria, 42 +/- 37 (n = 14, p = 0.007). RLX and Ro caused an additional increase of cAMP accumulation, 2- to greater than 10-fold increase over the sample incubated with Ro alone. There was no significant difference between proliferative and secretory phases (500 +/- 410, n = 6, and 470 +/- 300, n = 14, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1987

Regulation of prolactin production by progestin, estrogen, and relaxin in human endometrial stromal cells.

Human decidua synthesizes and secretes PRL. We identified the PRL synthesized in endometrial stromal cells and investigated the effect of medroxyprogesterone acetate (MPA), estradiol (E2), porcine relaxin (RLX), and RU486, an antiprogestin, on PRL production by stromal cells from non-pregnant endometrium in primary culture. Stromal cells were isolated from proliferative and secretory endometria and individually cultured in nutrient medium or medium supplemented with different hormone(s). The immunoreactive PRL isolated from culture medium of hormone-stimulated stromal cells was identified and compared to pituitary PRL. Bio-Gel elution pattern and mol wt analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting showed that PRL produced by stromal cells had properties identical to those of pituitary PRL. In addition, PRL mRNA was identified in hormone-stimulated stromal cells using human pituitary PRL cDNA as a hybridization probe. Analysis of mRNA by Northern blotting showed that the size of PRL mRNA isolated from stromal cells was indistinguishable from that of PRL mRNA in human decidua and pituitary tissue. These results indicated that PRL measured in culture medium was synthesized de novo by stromal cells. The PRL content in culture medium was quantitated by RIA. The PRL production rate in stromal cells cultured without hormones ranged from 6-10 ng/day.mg cell protein. After 4-5 days of incubation with RLX or MPA alone, the PRL production rate increased about 2- to 3-fold over the control value. E2 alone had either no effect or slightly decreased the stromal cell PRL production rate. Stromal cells responded to 0.02 microM MPA, and the maximal response was at 0.1-1 microM MPA. A further increase in PRL production was found when stromal cells were treated with a combination of MPA and E2 and MPA, E2 and RLX. In the presence of MPA or MPA and E2, 0.1 ng/ml relaxin increased the PRL production rate. A potent progestin antagonist, RU486, inhibited PRL production in stromal cells treated with MPA, MPA and E2, or MPA and RLX. These results indicate that endometrial PRL production is regulated by the combined effects of steroid hormones (progestin and estrogen) and a peptide hormone (relaxin).

Cells, Cultured↗
PubMed1986

Dinitrophenylated thiols in tryptic fragments of the heavy chain from chicken gizzard myosin.

Trypsin digestion of phosphorylated and 3H-labeled dinitrophenylated chicken gizzard myosin released major fragments of Mr 29,000, 50,000 and 66,000 in a ratio of close to one to one. They contained 58% of the label bound to thiols of the heavy chains; 28% of the label was bound to the light chains. The heavy chain fragments of Mr 29,000 and Mr 66,000 were dinitrophenylated when the enzyme activity was inhibited. The 3H-labeled dinitrophenylated myosin alone followed a somewhat different pattern in that the label was bound to the light chains predominantly. Thiolysis of the phosphorylated and dinitrophenylated myosin with 2-mercaptoethanol restored the K+ -ATPase (ATP phosphohydrolase, EC 3.6.1.32) activity and the dinitrophenyl group was removed from the N-terminal fragment of Mr 29,000 of the heavy chain, predominantly. In contrast, restoration of the enzymic activity occurred in thiolyzed dinitrophenylated myosin alone when the label was removed from the light chains rather than the tryptic fragments of the heavy chain. Phosphorylation induced conformational changes in gizzard myosin that altered the reactivity of the thiols in fragments of the globular heavy chain region.

Animals↗