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Biomedical subjects

D Hu

Publications and source records attributed to D Hu.

173 records · Page 10Linked to original sources
PubMed1990

Dumbbell metastatic cystosarcoma phyllodes of the heart and lung.

Cystosarcoma phyllodes is an uncommon breast tumor that rarely metastasizes. A case of dumbbell cystosarcoma phyllodes metastatic to the heart and lung diagnosed antemortem is described. The roles of diagnostic echocardiography and surgical excision are discussed. Atrial extension of a lung malignancy through a pulmonary vein is not an absolute contraindication to operation, but careful patient selection and operative planning are required.

Breast Neoplasms↗
PubMed1990

Insulin rapidly induces rat liver S14 gene transcription.

We evaluated the role insulin plays in the regulation of hepatic S14 gene transcription using the streptozotocin-induced diabetic rat model. Nuclear run-on activity and mRNAS14 levels were reduced by more than 85% in diabetic rats compared to those in intact animals. After the administration of insulin, both S14 run-on activity and mRNAS14 levels were rapidly induced. Within 1 h of insulin administration, S14 run-on activity and mRNAS14 were induced 5- and 8-fold, respectively. S14 gene expression was restored to intact levels within 4 h, with overall increases in run-on activity and mRNAS14 of 7- and 20-fold, respectively. The full induction of mRNAS14 cannot be accounted for solely by activation of S14 gene transcription, implicating insulin effects at the posttranscriptional level. However, our results show that the principal target for insulin action on the S14 gene is transcriptional. Administration of dibutryl cAMP and theophylline fully blocked the insulin-mediated increase in S14 gene transcription, indicating that hepatic cAMP levels play a dominant negative role in regulating S14 gene transcription in vivo. Fructose administration to starved diabetic rats induced only a marginal 60% increase in mRNAS14 and S14 run-on activity within 4 h, while insulin plus fructose or insulin plus glucose fully restored S14 gene expression to intact levels within the same time period. Thus, dietary fructose or a metabolite generated from fructose alone cannot induce S14 gene transcription or mRNAS14 to intact levels in the starved diabetic rat. Acute effects of dietary carbohydrate on hepatic S14 gene transcription are insulin dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Mosquito-net spraying with deltamethrin for malaria control].

Mosquito-nets were sprayed with 9.6mg deltamethrin per square meter for control of malaria vectors in Yibin County, Sichuan Province in 1986. In the study area, the relative population indices of Anopheles anthropophagus and An. sinensis in 35 mosquito-nets were 0.6 and 1.4 respectively; the man biting rates of these two vectors dropped by 97.8 and 90.8% respectively. The residual toxic effect of sprayed mosquito-nets, up to 104 days after spray, caused a mortality of 93.1-100% of An. anthropophagus and 87.1-100% of An. sinensis. The multiparous mosquito rate dropped by 48.4 and 51.3%. Indoor-intruding An. anthropophagus and An. sinensis were reduced by 76% and 78.3% respectively. The incidence of malaria decreased by 94.4%, the positive rate in school children declined by 77.5%. Both entomological and epidemiological indices indicated that mosquito-nets sprayed with deltamethrin could effectively control the malaria prevalence. This measure is economical and practical for control of malaria.

Animals↗
PubMed1988

Effects of clofilium on ischemic subendocardial Purkinje fibers 1 day postinfarction.

One day after ligation of the canine anterior descending coronary artery, clofilium, a long-acting class III antiarrhythmic agent, was studied for its effects on normal and ischemic Purkinje fibers. In normal Tyrode's solution (4 mM potassium, 2.7 mM calcium) clofilium (10(-7) to 10(-5) M) increased action potential duration. Although only 2 of 10 normal Purkinje fibers developed early after depolarizations and early afterdepolarization-initiated triggered activity, 10 of 11 ischemic Purkinje fibers developed these features. Consequently, action potentials in ischemic fibers were prolonged to durations greater than 10 s. The triggered activity in the ischemic Purkinje fibers produced repetitive activity in adjacent normal ventricular muscle. In vivo, 3 days after ligation, the administration of 3 to 10 mg/kg clofilium induced grouped beating. Action potentials recorded subsequently from these same hearts in vitro showed early afterdepolarizations, triggered activity and a similar grouping of responses. Therefore, clofilium differentially produced early afterdepolarizations in ischemic Purkinje fibers. This is a mechanism by which clofilium could be arrhythmogenic in an ischemic heart.

Action Potentials↗
PubMed1982

Dietary obesity in rats: influence on carbohydrate metabolism.

When male rats were fed a high diet from 3 to 20 weeks of age, they weighed 633 g which was 30% more than the animals fed a high glucose diet. Blood samples after a 16 to 18 hour fast, from the rats fed the high fat and high glucose diets contained, respectively: 130 +/- 11, 110 +/- 8 mg glucose/100 ml; 27 +/- 5, 24 +/- 3 microunits immunoreactive insulin (IRI)/ml; 791 +/- 58, 1104 +/- 179 meq nonesterified fatty acids (NEFA)/L. A tolerance test, by stomach tube, with 125 mg of glucose/100g body weight indicated that the rats fed the high fat diet had significantly higher mean plasma glucose concentrations, lower IRI responses and a lower leve of NEFA than rats fed a high glucose diet. Switching diets for 5 weeks resulted in body weights of about 600 g for both groups of rats. Those rats switched from the high fat to the high glucose diet did show an improved glucose tolerance, while the reverse was true of rats switched from the high carbohydrate to the high fat diet.

Animals↗
PubMedDate not supplied

Binding of IgG to amyloid beta A4 peptide via the heavy-chain hinge region with preservation of antigen binding.

Amyloid beta A4 peptide is found in the extracellular region of the senile plaque and in the angiopathy of Alzheimer's disease. Several other proteins, including IgG, also reside in these abnormal structures. In an attempt to understand how these structures are assembled and to determine how proteins are recruited, interactions of various proteins with synthetic beta A4 peptide have been examined in vitro. Purified IgG binds directly to synthetic beta A4 peptide with high avidity. The domain between amino acids 12-28 of beta A4 binds IgG. beta A4 peptide binds the hinge region of the immunoglobulin heavy chain, and preserves the ability of the immunoglobulin to bind antigen. A protein which does not bind directly to beta A4 peptide can be targetted to the senile plaque and angiopathy by binding to IgG, which avidly binds beta A4 peptide.

Amyloid beta-Peptides↗
PubMedDate not supplied

Effects of 17 beta-estradiol on early afterdepolarizations and L-type Ca2+ currents induced by endothelin-1 in guinea pig papillary muscles and ventricular myocytes.

By use of standard microelectrodes and whole cell patch clamp, the effects of 17 beta-estradiol on early afterdepolarizations (EADs) and increase of L-type Ca2+ currents (L-Ica) induced by endothelin-1 (ET-1) were studied in guinea pig ventricular papillary muscles and myocytes. The results indicated that superfusion with ET-1 for 30 min resulted in a marked prolongation of the action potential duration (APD) and caused stable EADs leading to triggered activity occurring at the plateau of the action potentials in isolated guinea pig ventricular papillary muscles. With the addition of 17 beta-estradiol (30 mumol/l), APD was shortened and EADs were decreased. In the patch clamp study, ET-1 induced an increase of mean peak L-Ica from 534.46 +/- 46.23 to 1003.15 +/- 39.12 (pA) with the peak voltage-current curve shifting to the left. When 17 beta-estradiol (30 mumol/l) was added, the L-Ica was decreased by up to 33.32% (p < 0.01) with the peak voltage-current curve shifting to the right. In contrast to the steady-state inactivation curve, ET-1 shifted the steady-state activation curve in the depolarization direction. However, with the addition of 17 beta-estradiol, the deviation of the steady-state activation and inactivation curves caused by ET-1 was suppressed. In conclusion, 17 beta-estradiol appears to attenuate the prolongation of APD and reduce EADs induced by ET-1 in guinea pig papillary muscles by its inhibitory effect on L-Ica.

Action Potentials↗