Biomedical subjects

B Yu

Publications and source records attributed to B Yu.

At least 127 records · Page 7Linked to original sources

PubMed1997

First trial of home ECG and blood pressure telemonitoring system in Macau.

OBJECTIVE: To determine the feasibility of home monitoring of patients with cardiac disease or hypertension. METHODS: An improved home electrocardiographic and blood pressure telemonitoring system linked to a central workstation was tested in 10 patients in Macau for 3 months. RESULTS: The total number of connections was 1377. Of the automatic alarm connections, 32.5% were false positive, with the percentage of false positives ranging from 7.6 to 54.6 for different patients. Both patients and physicians found the system easy to use. CONCLUSIONS: Further investigation is required to match the number of patients with the system capacity. A more robust dysrhythmia detection algorithm is needed to reduce the number of false alarms. Nevertheless, the results were sufficiently good that the trial is being expanded.

Blood Pressure Determination↗

PubMed1997

Dihydropyridine- and neurotoxin-sensitive and -insensitive calcium currents in acutely dissociated neurons of the rat central amygdala.

The central amygdala (CeA) is an area involved in emotional learning and stress, and identification of Ca2+ currents is essential to understanding interneuronal communication through this nucleus. The purpose of this study was to separate and characterize dihydropyridine (DHP)- and neurotoxin-sensitive and -resistant components of the whole cell Ca2+ current (ICa) in acutely dissociated rat CeA neurons with the use of whole cell patch-clamp recording. Saturating concentrations of nimodipine (NIM, 5 microM), a DHP antagonist, blocked 22% of ICa: this NIM-sensitive (L-type) current was recorded in 68% of CeA neurons. The DHP agonist Bay K 8644 (5 microM) produced a 36% increase in ICa in a similar proportion of CeA neurons (70%). omega-Conotoxin GVIA (CgTx GVIA, 1 microM) in saturating concentrations inhibited 30% of ICa, whereas omega-agatoxin IVA (Aga IVA, 100 nM), in concentrations known to block P-type currents, did not affect ICa. Higher concentrations of Aga IVA (1 microM) alone reduced ICa by 34%, but in the presence of NIM (5 microM) and CgTx GVIA (1 microM) blocked only 18% of ICa. omega-Conotoxin MVIIC (CgTx MVIIC, 250 nM) reduced ICa by 13% in the presence of CgTx GVIA (1 microM). Application of NIM (5 mM), CgTx GVIA (1 microM); and Aga IVA (1 microM) blocked approximately 67% of ICa. A similar portion (63%) of Ca2+ current was blocked with CgTx MVIIC (250 nM) in the presence of NIM (5 microM) and CgTx GVIA (1 microM). The current resistant to NIM and the neurotoxins represented 37% of ICa, whereas in neurons not having L-type currents the resistant current made up approximately 53% of ICa (49 +/- 2%, mean +/- SE). The resistant current activated at around -40 mV and peaked at approximately 0 mV with half-activation and -inactivation potentials of -17 and -58 mV and slopes for activation and inactivation of -5 and 13 mV, respectively. The resistant current was sensitive to Cd2+ (IC50 = 2.5 microM) and Ni2+ (IC50 = 86 microM), was larger in Ca2+ than in Ba2+ (ratio = 1.31:1), and showed a moderate rate of decay. In summary, our results show that the high-voltage-activated calcium current in rat CeA neurons is composed of at least four pharmacologically distinct components: L-type current (NIM sensitive, 22%), N-type current (CgTx GVIA sensitive, 30%), Q-type current [Aga IVA (1 microM) and CgTx MVIIC sensitive, approximately 13-18%], and a resistant current (Non-L, -N, and -Q current, 33 approximately 37%), amounting to 37-53% of the total current. The resistant current has some electrophysiological and pharmacological characteristics in common with doe-1, alpha 1E, and R-type calcium currents, but remains unclassified.

Amygdala↗

PubMed1997

The morphological changes of intestinal mucosa in growing rabbits.

The study aimed to increase understanding of digestive function from the development of the digestive tract from suckling to maturity in rabbits. The relative weights of the digestive tract (in relation to body weight) in different segments increase linearly during the rapid growth period between 2 and 8 weeks of age, thereafter intestinal weight gain is slower. An underdeveloped mucosal histology was observed in the hindgut of suckling rabbits at 2 weeks compared with 4 weeks of age. From SEM micrographs, the small intestinal mucosal villi look more slender and finger-like in the suckling period, thereafter becoming broader or tongue-like or plate-shaped in mature rabbits. The micrographs showed a compact arrangement in the underdeveloped hindgut mucosa at 2 weeks, but after weaning as hindgut fermentation becomes significant the mucosa increased in surface area.

Aging↗

PubMed1997

A home electrocardiography and blood pressure telemonitoring system.

A home electrocardiography (ECG) and blood pressure telemonitoring system for cardiac patients was installed in the Macau region. The monitoring centre was established in the emergency unit at the Government Hospital of Macau. The first users were 10 cardiovascular patients selected by a physician. The average age of these users was 61 years (range 30-78). The results of a three-month trial showed that the system was easy to operate and technically reliable. It was found to be helpful for cardiac patients. The most significant problem during the trial was electrical noise from the ECG electrodes.

Adult↗

PubMed1997

[HLA-DQA1 genes involved in genetic susceptibility to rheumatic fever and rheumatic heart disease in southern Hans].

The incidence of rheumatic fever (RF) or rheumatic heart disease (RHD) is high in southern China. We studied the genetic susceptibility of HLA-DQA1 alleles to RF or RHD with emphasis on the mechanisms 106 unrelated healthy individuals and 54 patients with RF or RHD of Chinese Han nationality in Guangdong were included. DNA extraction from various biological material using phenol/chloroform method and HLA-DQA1 genotyping by PCR-PAGE and then with silver dyeing was used to show the electrophoretic patterns. A total 6 alleles of HLA-DQA1 were found. Increased allele frequencies of DQA1*0101 (31.48%, RR = 2.89, P < 0.005, EF = 0.206) and decreased allele frequencies of DQA1*0102 (1.85%, RR = 0.106, P < 0.005, PF = 0.134) were observed. Two increased genotyping of HLA-DQA1 (DQA1*0101/0301, chi 2 = 8.84, P < 0.005 and DQA1*0101/0401, chi 2 = 6.23, P < 0.0025) and decreased genotyping of DQA1*0102/0301 (chi 2 = 11.98, P < 0.005) were also observed. These findings suggested that DQA1*0101 contribute to genetic susceptibility for RF or RHD in Guangdong hans while DQA1*0102 to its genetic resistance. Digesting the genotyping of HLA-DQA1 may provide scientific basis for finding susceptible individuals to RF or RHD. Using PCR-PAGE and silver dyeing technique, a new genotyping method for HLA-DQA1, which is simple sensitive and precise, was established and applied.

Adolescent↗

PubMed1997

Effects of superoxide anion, B(alpha)P and TPA on the membrane fluidity of NIH3T3 cells.

The membrane fluidity of NIH3T3 cells treated with low and high concentration of cell stimulatives (extracellular generated superoxide anion(O2-.),12-O-tetra-decanoyl-phorbol-13-acetate(TPA), and benzo(alpha)-pyrene[B(alpha)P]) was investigated by means of fluorescence labels 1,6-diphenyl-1,3,5 hexatriene (DPH) and N-(3-pyrene) maleimide (N(3p)M). The high concentration of O2-., TPA, B(alpha)P greatly increased the fluidity of cell membrane lipid domain. No changes of the florescence polarization of DPH was found in membrane lipid domain treated with low concentration of O2-., TPA, and B(alpha)P. However, decrease in the fluoresence polarization of N(3p)M on the cell membrane protein domain damaged by low concentration of cell stimulatives was observed, showing that these treatment could influence the conformation of membrane protein. The possible relationship between the changes of the conformation of membrane protein and the cell transformation and its carcinogenic machenisms were discussed.

3T3 Cells↗

PubMed1997

[Serial modifications of bacon's pull through resection for low rectal cancer].

Four modifications of Bacon's pull-thru resection were undertaken to improve postoperative defecatory control and to avoid the 2nd stage resection of the pull-thru colon stump. 54 cases of modified Bacon's rectal resection (9.64% of sphincter saving resections) were performed between 1954-1989. The 1st modification (1954) preserves the levator ani and the intact anorectal ring. The 2nd modification (1964) preserves the dentate margin and anal transitional zone (acute anal sensation), thus greatly improving defecatory control. The 3rd modification (1980) simplified intraanal resective procedure. The 4th modification (1991) was to encircle and ligate the distal end of colon over a sterilized corrugated intraluminal splinting tube (The other end of which is already connected to a long latex tube prior to operation). The latex tube was pulled out thru anus, until the colonic ligature reaches the Dentate margin, to substitute for colonic pull-thru and to divert feces during & after operation, 4-8 fine stitches approximate the colon wall 1 cm proximal to the ligature, to the cut edge of anal mucosa. The colon wall distal to the ligature sloughed in 7-10 days, the proximal colon has partially healed to the raw areas of anal canal without infection. The 2nd stage colon stump resection is thus obviated and hospitalization shortened. The postoperative anal function was good in 86.66%. Modified Bacon's operation is indicated for very low rectal cancer when the rectal remnant above levator ani after adequate resection is less than 1 cm which is difficult for intraabdominal anastomosis. It extends the scope of sphincter-saving operation. It is a good substitute for Park's coloanal anastomosis.

Defecation↗

PubMed1997

[Primary curative incision in the treatment of perianorectal abscess].

More than 50% of the patients with perianorectal abscess treated with traditional incisional drainage will lead to fistula formation postoperatively. We present a procedure of primary curative incision for treatment with perianorectal abscess without fistula formation. The result of primary curative incision in comparison with traditional incisional drainage in a randomized control study showed that the incidence of postoperative fistula formation and recurrent abscess was 2.56% in the former and 56.25% in the latter. The key points of the procedure were discussed in detail and the causes and prevention of the disease occurred after injection of sclerotic drugs for hemorrhoids were also discussed.

Abscess↗

PubMed1997

[Preliminary study on the effects of Nd-Fe-B magnet on trace elements in rhesus monkeys].

Three adult rhesus monkeys were selected. Two of them were fixed with Nd-Fe-B magnets on the palates respectively. Nd-Fe-B magnet was not used in one monkey. Blood was drawn from all monkeys. Ten kinds of trace elements in blood were measured. The result showed that there was no quantitative difference in ten kinds of trace elements between the experimental and control animals.

Animals↗

PubMed1997

[Effects of low concentration carbon monoxide on human physiological function].

Human volunteers were exposed to various low concentrations of carbon monoxide (CO) in a closed cabin. The results showed that 35 mg/m3 of CO caused slight subjective symptoms and reduction in contrast vision, operating efficiency and T-wave of ECG. At 80 mg/m3 and 115 mg/m3 the above changes were more severe and a rise in hearing threshold level was observed. It demonstrated that an inhibitory effect on the CNS and heart were caused by low concentrations of CO. According to the absorption curves for human exposed to CO, it is suggested that the sense effect level and vision effect level for CO are 7% COHb, and the hearing effect level is 9% COHb.

Aerospace Medicine↗

PubMed1997

Influences of cane length on the stability of stroke patients.

The purpose of this study was to investigate the influence of cane length on the standing and walking stability of stroke patients. Ten stroke patients were used as subjects and evaluated by using two different cane lengths based on the measurements of the distance from distal wrist crease to the ground (WC cane), and the distance from greater trochanter to ground (GT cane). Force plates were used to determine the center of pressure (COP). The maximum sways, the total travel distances, and the mean travel speeds of the COP were analyzed for each patient standing and walking with and without canes. It was found that the total travel distance and the mean travel speed of the COP in the medial-lateral (M-L) direction were significantly lower when standing with a cane than when standing without one. It was also found that the values of these parameters and the maximum sways of the COP in both anterior-posterior (A-P) and M-L directions were significantly lower when standing with the WC cane than when standing with the GT cane. No significant difference was found in the maximum M-L sway, the total travel distance, and the mean travel speed of the COP in walking. These results suggest that the standing stability of stroke patients is improved by using canes, especially by using a WC cane, although no significant influence of using canes on the walking stability was detected. Based on the results of this study, the vertical distance from the wrist crease to ground is recommended as the appropriate cane length for stroke patients.

Adult↗

PubMed1997

Organization and sequence of human cardiac myosin binding protein C gene (MYBPC3) and identification of mutations predicted to produce truncated proteins in familial hypertrophic cardiomyopathy.

Cardiac myosin binding protein C (MyBP-C) is a sarcomeric protein belonging to the intracellular immunoglobulin superfamily. Its function is uncertain, but for a decade evidence has existed for both structural and regulatory roles. The gene encoding cardiac MyBP-C (MYBPC3) in humans is located on chromosome 11p11.2, and mutations have been identified in this gene in unrelated families with familial hypertrophic cardiomyopathy (FHC). Detailed characterization of the MYBPC3 gene is essential for studies on gene regulation, analysis of the role of MyBP-C in cardiac contraction through the use of recombinant DNA technology, and mutational analyses of FHC. The organization of human MYBPC3 and screening for mutations in a panel of French families with FHC were established using polymerase chain reaction, single-strand conformation polymorphism, and sequencing. The MYBPC3 gene comprises > 21,000 base pairs and contains 35 exons. Two exons are unusually small in size, 3 bp each. We found six new mutations associated with FHC in seven unrelated French families. Four of these mutations are predicted to produce truncated cardiac MyBP-C polypeptides. The two others should each produce two aberrant proteins, one truncated and one mutated. The present study provides the first organization and sequence for an MyBP-C gene. The mutations reported here and previously in MYBPC3 result in aberrant transcripts that are predicted to encode significantly truncated cardiac MyBP-C polypeptides. This spectrum of mutations differs from the ones previously observed in other disease genes causing FHC. Our data strengthen the functional importance of MyBP-C in the regulation of cardiac work and provide the basis for further studies.

Base Sequence↗

PubMed1997

Effect of peroxovanadate compound on phosphoenolpyruvate carboxykinase gene expression and lipid metabolism in diabetic rats.

Although it was proved that peroxovanadate-nicotinic acid (POV) can decrease hyperglycaemia and hyperlipaemia, its molecular biochemical mechanism of action is unclear. The present investigation aimed at studying the effect of POV on gene expression and enzymatic activity of hepatic phosphoenolpyruvate carboxykinase (PEPCK) and blood lipid metabolism in streptozotocin-diabetic rats in order to suggest the molecular biochemical mechanism of POV action in lowering hyperglycaemia and hyperlipaemia. The results showed that the gene expression and enzymatic activity of hepatic cytosolic PEPCK, which were increased in diabetic rats, were significantly reduced following POV treatment. Similarly, POV was shown to oppose significantly the hyperglycaemia and hyperlipaemia in these diabetic rats. These results suggested that a possible mechanism of POV action was to inhibit PEPCK gene expression as well as PEPCK activity which could explain the reduced gluconeogenesis and hyperglycaemia.

Analysis of Variance↗

PubMed1997

Differential regulation of the pocket domains of the retinoblastoma family proteins by the HPV16 E7 oncoprotein.

The human papillomavirus E7 oncoprotein binds to the retinoblastoma (Rb) tumor suppressor protein, and the binding to Rb correlates with the oncogenic potential of E7. Recent studies from several laboratories indicated that the half-life of the Rb protein is reduced in cells that are stably transformed with E7, suggesting that E7 could induce the proteolytic degradation of Rb. To investigate whether the Rb degradation is a primary effect of E7 or a result of altered cell phenotype, we sought to develop assays that can distinguish between the two possibilities. Using recombinant adenovirus expressing the human papillomavirus type 16 E7 protein, we show that the expression of E7 leads to an increased rate of decay of the Rb protein. Moreover, Rb degradation immediately follows the expression of E7 suggesting that it is an early and primary effect. Consistent with a previous study, we observed that the E7-induced degradation of Rb can be blocked by the inhibitors of the 26S proteasome. We have also developed a transient transfection assay for the E7-induced degradation of Rb. Using this assay, we show that the pocket domain of Rb is necessary and sufficient for the E7-induced degradation. However, the proteolysis is relatively specific for Rb because the level of p107 or p130 was not significantly altered by the expression of E7. Thus, although E7 binds to all three members of the Rb family of proteins, the proteolysis is much more efficient in the case of Rb. In the transient transfection assays, adenovirus E1A and SV40 large T antigen failed to induce degradation of Rb, suggesting that the Rb degradation is a unique property of the E7 oncoprotein.

Acetylcysteine↗

PubMed1997

[Hypoglycemic effects of peroxovanadate complexes on glucose transportor of diabetic rats].

OBJECTIVE: To demonstrate the hypoglycemic effects and translocation of glucose transport (Glut 1 and Glut 4) promoted by peroxovanadate and nicotinic acid complexes (POR) in streptozotozin-induced diabetic rats. METHODS: Peroxovanadate complexes nicotinic acid (POR) was prepared in laboratory. POR and vanadate were administered in drink water. The muscles from diabetic rats were subjected to sucrose density gradient centrifugation to prepare plasma membrane and microsome membrane. Antibodies to COOH-terminal of glucose transportor were used in Western Blot to evaluate the translocation. RESULTS: Peroxovanadate complexes of nicotinic acid (POR) showed marked hypoglycemic effects on STZ-induced diabetic rats. 1mg/kg oral pathway POR could significantly reduce the plasma glucose levels (from 18.95 +/- 2.61mmol/L to 6.36 +/- 2.23mmol/L, t = 12.233, P < 0.01) over four week's treatment, whereas, same dose of single sodium vanadate or nicotinic acid did not have hypoglycemic effects. The net vanadium intake was about 1/90 of single effectively vanadate treatment. When Western blot was used POR increased the translocation of Glut 4 and Glut 1 from intracellular site of plasma membrane. CONCLUSION: Peroxovanadate-nicotinic acid complexes (POR) are the novel vanadyl that markedly reduce plasma glucose in a lower dose comparing to vanadate in STZ-DM rats by oral administration. Translocation of glucose transportor may play a part in hypoglycemic mechanism.

Animals↗

PubMed1997

Effects of peroxovanadate complexes on reducing glycemia in diabetic rats and translocation of glucose transporter.

OBJECTIVE: To demonstrate the hypoglycemic effects and translocation of glucose transporter (Glut 1 and Glut 4) promoted by peroxovanadate and nicotinic acid complexes (nicotinic chelated bitriperoxovanadate, POR; N-O nicotinic chelated peroxovanadate, POV) in streptozotozin-induced diabetic rats. METHODS: Peroxovanadate complexes of nicotinic acid (POR and POV) were prepared and characterized in laboratory. POR, POV and vanadate were administrated in drink water. The muscles from diabetic rats were subjected to prepare plasma membrane and microsome membrane. Antibodies to COOH-terminal of glucose transporter were used in Western Blot to evaluate the translocation. RESULTS: POR and POV showed markedly hypoglycemic effects in streptozotocin (STZ)-induced diabetic rats. POV, which may be a N-oxide compound of peroxovanadate, have high potency of acute effects comparing to carboxylate-complexes of peroxovanadate (POR). In chronic tests, 1 mg/kg oral pathway POR could significantly reduce the plasma glucose levels over four week's treatment, whereas the same dose of single sodium vanadate or nicotinic acid did not have hypoglycemic effects. The net vanadium intake is about 1/90 of single effectively vanadate treatment. The Western Blot showed that POR increased the translocation of Glut 4 and Glut 1 from intracellular site of membrane. CONCLUSIONS: Peroxovanadate-nicotinic acid complexes (POR and POV) are the novel vanadyl that acutely and markedly reduce plasma glucose in a lower dose comparing to vanadate in STZ-DM rats by oral administration. Translocation of glucose transportor may take a part in their hypoglycemic effects.

Animals↗

PubMed1997

[Clinical characterizations of familial diabetes mellitus associated with mitochondrial gene mutation].

OBJECTIVE: To discuss clinical features at diabetic subtype which is apparently caused by a single mutation in the mitochondrial tRNA(Leu(UUR)) gene. METHODS: According to WHO criteria of diabetes mellitus (DM), 130 patients with DM and the family history of DM (either NIDDM or IDDM) were screened by using genetic diagnosis. Clinical and laboratory analyses were made in three unrelated patients with the mutation in mtDNA and their relatives. RESULTS: Four unrelated subjects (3.1%) were detected with mutation at position 3243 of mitochondrial DNA. The nine diabetes patients from first degree relatives of three probands were also identified with the mutation, in which eight patients were associated with sensory hearing loss and required insulin therapy due to secondary failure to oral hypoglycemic agents. All these nine patients had a lower frequency of obesity in the past, and most of them had a mother with diabetes, were younger at diagnosis, and were generally accompanied by in paired insulin secretion. CONCLUSION: Since the patients have the clinical characteristics of maternal transmission, hearing loss and impaired insulin secretion, we conclude that maternally inherited diabetes and deafness (MIDD) is a new diabetes subtype associated with a single mitochondrial mutation.

Adult↗

PubMed1996

Effects of site-directed mutagenesis of basic residues (Arg 94, Lys 95, Lys 99) of lipopolysaccharide (LPS)-binding protein on binding and transfer of LPS and subsequent immune cell activation.

LPS-binding protein (LBP) is a 60-kDa acute phase glycoprotein capable of binding the LPS of Gram-negative bacteria and facilitating its diffusion. This process is thought to be of potential importance in inflammatory reactions and pathogenic states such as septic shock syndrome. Here, we report on the identification of a LPS binding domain within the LBP molecule and on the identification of single amino acids important for binding of LPS by LBP. Several synthetic LBP peptides inhibited LPS-LBP interaction, and amino acids Arg 94 and Lys 95 were centrally located in these inhibitory peptides. LBP mutants with amino acid exchanges within this region were expressed and tested in five different functional assays: binding to immobilized LPS; facilitation of binding of LPS aggregates to monocytes; transfer of LPS monomers from aggregates to soluble CD14; transfer of soluble CD14-bound LPS monomers to high density lipoprotein (HDL); and enhancement of LPS-induced cell activation. The double mutant Glu 94/Glu 95 was completely lacking LPS binding, transfer, and cell stimulatory activity, indicating that the integrity of amino acids 94 and 95 is required for LBP function. While mutations of amino acids Arg 94 or Lys 95 into alanine reduced the LPS binding activity of LBP dramatically, the ability to facilitate binding of LPS aggregates to membrane CD14 at the cell surface was retained. These findings emphasize the distinction between binding of LPS aggregates to cells, which is not associated with cell stimulation, and binding of LPS monomers to CD14, which leads to cell stimulation.

Acute-Phase Proteins↗