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Biomedical subjects

F F Wang

Publications and source records attributed to F F Wang.

At least 37 records · Page 2Linked to original sources
PubMed1993

[The glycemic effect of glutinous rice dumplings in non-insulin-dependent diabetes mellitus].

Postprandial hyperglycemia is a known physiological effect in diabetics. The glycemic index classifies starchy carbohydrate foods into predictable postprandial glycemic responses and was thought to be a useful tool for the planning of diabetic diets. Recently, There has been some debates over the applicability of the glycemic index to mixed meals. The purpose of this study was to study the glycemic effect of glutinous rice dumplings, a mixed food, on non-insulin-dependent diabetics and discuss the applicability of rice dumplings in diet planning. A total of 31 patients with non-insulin-dependent diabetes mellitus participated in this study. The ingredients of the glutinous rice dumplings included 60 grams glutinous rice, 30 grams lean meat, 1/3 of a salted egg yolk, and 1/3 of a mushroom. After a preprandial blood sample, each subject ate one rice dumplings. Postprandial blood samples were taken at 30, 60, 90 and 120 minutes respectively. The glucose hexokinase method was used to determine the plasma glucose value. Subjects were divided into two groups (poor control group and fair control group) by preprandial blood glucose, the cutoff point was 140 mg/dL. For the poor control group, the preprandial value was 226.0 +/- 62.2 mg/dL compared to 102.8 +/- 19.0 mg/dL in the fair control group. The values for the poor and fair control groups postprandially were: 30 minutes, 212.7 +/- 47.6 mg/dL vs 138.3 +/- 30.3 mg/dL; 60 minutes, 259.5 +/- 51.8 mg/dL vs 189.9 +/- 34.6 mg/dL; 90 minutes, 291.5 +/- 69.5 mg/dL vs 210.6 +/- 46.4 mg/dL; and 120 minutes, 297.1 +/- 80.0 mg/dL vs 196.6 +/- 54.0 mg/dL.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Epidemiological study of gestational diabetes mellitus in Taipei and factors effecting blood glucose].

The prevalence of non-insulin-dependent diabetes mellitus has increased significantly in the last decade. Meanwhile, it has been found that patients with gestational diabetes have a greater chance of developing diabetes than normal subjects. This study was designed to survey the prevalence of GDM in metropolitan Taipei. A screening test with 50 g of glucose was performed on pregnant patients between 24 and 28 weeks of gestation, and a blood sample was collected one hour after ingestion. The subjects with a plasma glucose level over 130 g/dL were scheduled for a standard 75 g oral glucose tolerance test for diagnosis. Altogether, 872 pregnant women participated in the study. According to the WHO criteria which were published in 1985, a total of 224 (25.7%) subjects had a positive screening test. Thirty-seven (4.2%) subjects had impaired glucose tolerance (IGT) and five (0.6%) subjects were found to have GDM after the 75 g OGTT. Comparisons of the glucose levels of women of different ages (< 30 and > or = 30), BMI (< or = 24 and > 24), and parity (0 and > or = 1) demonstrated that women over 30, with a BMI over 24, or a parity over 1 had a significantly higher plasma glucose level than their counterparts in the screening test. Even after BMI-adjustment, the difference was still significant for the age and parity comparisons.

Adult↗
PubMed1992

[Effects of crude extract of earthworm on promoting blood circulation to removing stasis].

The crude extract of earthworm which has a thrombolytic effect could significantly decrease the plasma fibrinogen content and euglobulin lysis time (P < 0.01). An enzymatic preparation, containing many fibrinolytic enzymes, was prepared from the crude extract by ammonium sulphate precipitation and DEAE-cellulose chromatography. When administered in rabbits, the enzymatic preparation had an effect in hemorheology improvement. The experiment shows the enzymatic preparation could obviously lower the aggregation of platelets, decrease the viscosity of whole blood and plasma as well as the index of erythrocyte rigidity significantly (P < 0.001). All these effects demonstrated its ability in promoting blood circulation to remove stasis.

Animals↗
PubMed1992

Pen injector for insulin-requiring diabetic patients.

To compare the metabolic control and acceptability of a pen injector to the traditional syringe used in diabetes, 12 non-insulin-dependent diabetes mellitus (NIDDM) patients and six insulin-dependent diabetes mellitus (IDDM) patients were followed-up at the outpatient clinic of the Taipei Municipal Yang-Ming Hospital. All patients participated in a four-week run-in period and 24-week randomized cross-over design study. Human NPH insulin (Protaphane HM) in vials and in penfills were used in each 12-week experimental period, respectively. Metabolic control was assessed by a biochemical examination (before and after seven months of treatment) and HbA1c levels (at Weeks 1, 4, 16 and 28) and was found to be unchanged. The overall mean blood glucose declined slightly in both treatment modalities but not to a significant level (mean +/- SE; run-in: 175 mg/dL +/- 10 mg/dL; pen: 159 mg/dL +/- 8 mg/dL; syringe: 156 mg/dL +/- 7 mg/dL). The number of hypoglycemic episodes and self-adjustments of insulin dosage did not differ significantly between pen and syringe treatments. At the end of the study, a questionnaire revealed that eight patients would choose pen injectors, nine patients syringes and one was unsure of what to use as a future preference. The limitation of 36 units per injection of insulin is a drawback for those NIDDM patients with insulin resistance. An insulin delivery device that would allow an injection of a larger quantity of insulin is desirable for some patients.

Adolescent↗
PubMed1991

Expression of c-myc proto-oncogene during podophyllotoxin induced IW32 erythroleukemia cell differentiation.

The effect of hemin or podophyllotoxin on the differentiation of the erythropoietin (epo)-producing IW32 erythroleukemia cells was investigated. Podophyllotoxin induced IW32 cells to differentiate, and hemin potentiated the differentiation. Hemin had no effect on cell proliferation whereas podophyllotoxin inhibited cell growth. c-myc mRNA levels decreased biphasically by hemin or podophyllotoxin, while the combined treatment of hemin plus podophyllotoxin did not result in the initial decrease in c-myc mRNA level. Our data suggested that down-regulation of c-myc expression was not a prerequisite of IW32 cell differentiation induced by hemin and podophyllotoxin combined.

Animals↗
PubMed1991

Somatostatin inhibits pepsinogen secretion via a cyclic AMP-independent pathway.

Frog esophageal mucosa contains peptide glands which release pepsinogen in response to a variety of secretagogues and serves as a model to examine the inhibitory action of somatostatin. The pepsinogen secretion in response to bethanechol was inhibited by somatostatin in a noncompetitive fashion. The maximal response induced by bethanechol was reduced and the EC50 for bethanechol was increased in the presence of somatostatin. On the other hand, somatostatin showed essentially no effect on pepsinogen release evoked by ionophore A23187, dibutyryl cAMP or by forskolin in the presence of atropine. Atropine was included in the incubation mixture to eliminate the effect of acetylcholine released by forskolin from the intrinsic cholinergic neurons also present in the mucosa. Somatostatin did not exert any significant effect on the basal or the forskolin-stimulated cAMP accumulation in the mucosa, nor the basal or the forskolin-stimulated adenylate cyclase activity in the membranes of the peptic cells isolated from the mucosa. Thus, these results seem to suggest that somatostatin inhibits pepsinogen secretion from frog esophageal mucosa by a cAMP-independent pathway.

Adenylyl Cyclases↗
PubMed1991

Potentiation of thyrotropin-releasing hormone-stimulated prolactin mRNA levels in GH3 cells by acetylcholine.

We have examined the effect of acetylcholine (ACh) pretreatment on the thyrotropin-releasing hormone (TRH) induced prolactin gene expression in GH3 cells, a rat pituitary tumor cell line. Prolonged exposure (greater than 6 h) to ACh enhanced the TRH-induced prolactin mRNA accumulation in a time- and concentration-dependent manner while ACh by itself did not affect the basal prolactin mRNA levels appreciably. Maximal augmentation of the TRH-induced prolactin mRNA accumulation was obtained when cells were pretreated with 10(-5) M ACh for 24 h. The activation was mimicked by carbachol and oxotremorine and was blocked by the simultaneous presence of atropine. Preincubation of GH3 cells with pertussis toxin abolished the augmenting effect of ACh. These results indicate that prolonged exposure to muscarinic receptor agonists may enhance the TRH-stimulated prolactin mRNA expression and a pertussis toxin sensitive G-protein may be involved.

Acetylcholine↗
PubMed1990

Induction of fos and sis proto-oncogenes and genes of the extracellular matrix proteins during butyrate induced glioma differentiation.

Sodium butyrate has been shown to inhibit the growth and induce the differentiation of F-98 rat glioma cells. In agreement with the morphological changes, we have found that mRNAs for fibronectin and collagen in these cells could be reversibly induced by butyrate. While Ki-ras mRNA levels remained relatively unchanged, mRNAs for fos and sis increased significantly during the course of butyrate induced differentiation. c-fos induction can be detected 30 min after butyrate addition, a peak level (greater than 20 fold) was reached at 2 h, with a subsequent gradual decline. c-sis induction was detectable 24 h after butyrate exposure, at which time the cells have assumed morphological transition. Interestingly, the sis mRNA induction was not reversible upon butyrate withdrawal. The sis mRNA half-life increased from 40 min in the untreated cells to 100 min in the butyrate induced cells indicating that the increase in the stability of sis mRNA contributed, at least in part, to the elevated levels of sis expression. These findings demonstrate a coordinated induction of fibronectin and collagen genes in the butyrate-treated F-98 cells. In addition, fos and sis transcripts were differentially induced; a rapid and transient induction of fos followed by an irreversible induction of sis at a later stage of differentiation.

Animals↗
PubMed1989

Identification of the erythropoietin receptors of erythroleukemic cells.

Erythropoietin (epo) is the physiologic regulator of red blood cell development. We have demonstrated the presence of epo receptors on two erythroleukemia cell lines, IW32 and IW201. IW32 produces epo constitutively while IW201 is a nonproducing cell line. Neither cell lines respond to epo to differentiate. In this study, we have shown that these cells bound 125I-epo specifically. Binding could be displaced by the presence of unlabeled epo but not by insulin or epidermal growth factor. In contrast to that found in epo responsive cells isolated from Friend virus infected mouse spleen, which were reported to contain both "high" and "low" affinity receptors, our finding indicated only a single class of "low" affinity receptors with apparent dissociation constants of 1.7 nM and 2.0 nM for IW32 and IW201 cell lines, respectively. It is suggested that the absence of "high" affinity receptors may account for the lack of responsiveness of these cells to epo.

Animals↗
PubMed1989

Forskolin stimulation of pepsinogen secretion from frog esophageal mucosa is partly mediated by intrinsic cholinergic neurons.

Forskolin was found to stimulate pepsinogen secretion from frog esophageal mucosa. The stimulation was dose-dependent and was accompanied with a great increase in tissue cAMP content. The response to forskolin mimicked the action of bethanechol and was not additive with bethanechol. The stimulatory effect of forskolin was inhibited by 50% in the presence of either atropine or tetrodotoxin. On the other hand, incubation in a calcium-free medium not only reduced the response to forskolin by 45% but also eliminated the influence of atropine and tetrodotoxin. These results indicate that forskolin may stimulate pepsinogen secretion from the frog esophageal mucosa via activating adenylate cyclase, and part of its effect may arise from eliciting acetylcholine release from the intrinsic neurons.

Animals↗
PubMed1988

Identification of erythropoietin receptors in isolated membranes from Friend virus infected mice spleen cells.

It has been shown that radiolabeled erythropoietin (epo) specifically binds to homogeneous epo-responsive spleen cells from mice infected with the anemic variant of the Friend virus. We now report that membranes isolated from these cells retain the ability to specifically bind epo. Spleen cells were swollen in ice-cold 10 mM Tris-Cl pH 7.4 containing 0.2 mM phenylmethyl sulfonylfluoride for 5 minutes, after which the cells were homogenized and centrifuged to remove nuclear fraction. Membranes were collected by centrifuging the supernatant at 75,000 g for 90 min. Utilizing 3H-epo labeled at the terminal sialic acids of the carbohydrate moieties or 125I-epo labeled at the tyrosine residues, it was shown that the isolated membranes contained specific epo binding sites. About 90% of the binding could be inhibited by the presence of unlabeled epo whereas no inhibition was seen with other glycoproteins and growth factors. Equilibrium could be reached in approximately 2.5 hr at 25 degrees C or 1.5 hr at 37 degrees C. Binding could be saturated at an epo concentration of about 3 nM, Scatchard analysis indicated a single class of receptors with a Kd of approximately 1.5 nM.

Animals↗
PubMed1986

Structural characterization of human erythropoietin.

Erythropoietin is the primary regulator of red blood cell formation in mammals. Because of its extreme scarcity, very little information is available regarding structural features of this important glycoprotein. We report here the primary structure of human urinary erythropoietin, determined by protein sequencing. In addition, the sites of glycosylation, assignment of disulfide bonds, and the circular dichroism of the hormone analyzed for secondary structure in comparison with the prediction from the sequence are presented.

Amino Acid Sequence↗
PubMed1985

Some chemical properties of human erythropoietin.

Erythropoietin (epo) is the glycoprotein hormone that induces normal red cell differentiation. Reaction of native or denatured epo with either [3H]iodoacetic acid or N-ethyl-2-[3H]maleimide did not result in the incorporation of any significant amount of radioactivity. Radiolabeling took place only if the protein were denatured before reduction and alkylation. When reduction was carried out in the presence of 6 M guanidine HCl, about 3.7 mol N-ethyl-2[3H]maleimide were covalently linked per mol epo. These results show that there are no free, accessible sulfhydryl groups in epo; there are two internal disulfide bonds. When epo was reduced in the presence of 6 M guanidine HCl and then reoxidized and the guanidine removed, about 85% of the biological activity was regenerated. The biological activity was lost irreversibly if the sulfhydryl groups were alkylated. Limited proteolysis of [3H]epo (labeled at sialic acid residues of the oligosaccharide chains) showed that it consists of two rather trypsin-resistant domains, each having a mol wt of about 16,000, connected by a small region of protein that is trypsin sensitive. The two large fragments contain most of the label. Biological activity and immunoreactivity are lost after limited tryptic proteolysis. Complexing epo with a neutralizing antibody protects its activity from proteolysis.

Chemical Phenomena↗
PubMed1985

The role of carbohydrate in erythropoietin action.

The carbohydrate composition of human erythropoietin (epo) was determined by micro-GLC. Enzymic removal of most of the sugars results in aggregation of glycosidase-treated epo, loss of biological activity when assayed in mice, and retention of activity when assayed in marrow cell cultures or by RIA. Endoglycosidase F causes the removal of most of the carbohydrates indicating that the oligosaccharides are asparagine linked. The lack of O-linked sugar is confirmed by the absence of N-acetylgalactosamine. These findings indicate that the oligosaccharide portion of epo, although required for action in vivo, is not required for interaction with the target cells of the blood-forming system.

Carbohydrates↗
PubMed1983

Purification of a human urinary colony-stimulating factor.

Colony-stimulating factor (CSF), a protein required for the in vitro formation of colonies composed of granulocytes and/or macrophages, was isolated from the urine of anemic patients by using a seven-step procedure. The purified, homogeneous CSF had a specific activity of 1.9 X 10(8) U/absorbance unit at 280 nm (AU). This represents an overall purification of 25,330-fold and a total recovery of 3.8%. Upon iodination of the protein, the radioactivity migrated on sodium dodecyl sulfate (SDS) gel electrophoresis as a single peak with an apparent molecular weight of 46,000; reduction with mercaptoethanol caused dissociation to a single component of molecular weight 23,000. Only the dimer is active in stimulating colony formation. Urinary CSF stimulates formation of colonies comprising only macrophages in the mouse bone marrow cell culture assay. A neutralizing antibody raised against mouse L-cell CSF did not neutralize the activity of the urinary CSF but did bind it. This may indicate that the relative positions of antibody binding sites and the active sites are different in these two glycoproteins.

Chromatography↗
PubMed1979

A comparison by 220-MHz NMR of histidine hydronium ion titrations in porcine pancreatic ribonuclease and an extensively deglycosylated derivative.

220-MHz NMR was used to observe the titration behavior of the 5 histidine residues in porcine pancreatic ribonuclease (ribonucleate pyrimidine-nucleotido-2'-transferase (cyclizing), EC 3.1.4.22) and a derivative prepared by removal of 80% of the attached carbohydrate from this glycoprotein. Resonances due to histidine C-2 protons were observed over the full pH range for 3 of the residues; such resonances for the remaining 2 histidine residues broadened out as the pH was increased. Resonances due to histidine C-4 protons were also observed for 2 of the residues. The titration curves for both proteins were identical within experimental error. Resonances were assigned by comparison with histidine NMR titrations in ribonucleases from other species. Histidine 105, immediately adjacent to the site of attachment of a heterosaccharide side chain, has a C-2 proton chemical shift and pK that are insensitive to the large alteration in the bulk of the carbohydrate side chain. The chemical shifts of the C-2 proton of histidine 48 and of the C-4 proton of histidine 80, histidine residues that are close to one another and to another heterosaccharide side chain, show a similar insensitivity. The observations are direct evidence in support of the thesis that the heterosaccharides in porcine ribonuclease project away from the surface of the protein into the solution environment.

Animals↗