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Biomedical subjects

S Bai

Publications and source records attributed to S Bai.

72 records · Page 4Linked to original sources
PubMed1995

[A new technique of esophagogastrostomy above the aortic arch--covering and suspending of the anastomotic area with mediastinal pleura flap].

The postoperative anastomotic leakage is the most severe complication and the principal cause of death after resection of esophageal carcinoma. Especially, anastomosis above the aortic arch is accompanied by high incidence of anastomotic leakage usually with fatal prognosis. The authors improved the conventional method of anastomosis by using a mediastinal pleura flap to cover and suspend the anastomotic area with excellent result. From January of 1990 to April of 1995, 210 patients with esophageal carcinoma were so treated. No anastomotic leakage or stricture developed. Only one patient died of extensive myocardial infarction with an overall mortality of 0.47%. The major merit of this procedure was that the mediastinal pleura flap could cover the area of anastomosis and sustain the dragging force acting on this area, providing a better condition for the anastomosis to heal and thus reducing the possibility of anastomotic leakage.

Adult↗
PubMed1994

[Association of polymorphism for HLA-DQA1 promotor region (QAP) with IDDM].

We have identified the DNA polymorphism for the HLA-DQA1 promotor region (QAP) in patients with early and late onset insulin-dependent diabetes mellitus (IDDM) by PCR direct sequencing. The result showed that single nucleotide substitution at position-92(C-->T-92) and -146 (T-->C-146) were detected in QAP for early and late onset IDDM respectively. These findings suggests that the mutation seems to alter the conformation of QAP so that these are likely to influence the aberrant expression of MHC-class II loci in beta-pancreatic islet cells.

Base Sequence↗
PubMed1993

Identification of proximal and distal regulatory elements of the rat connexin32 gene.

We have investigated the genetic basis of the transcriptional regulation of the rat connexin32 gene which encodes the major gap junction protein in rat liver. Primer extension analysis of RNA isolated from adult rat liver identified multiple initiation sites clustered between -110 bp and -50 bp upstream from the translation start codon. An approx. 760 bp genomic DNA fragment upstream of the first exon which included the mRNA start sites was cloned 5' to the luciferase reporter cassette in p19LUC to yield pCx32-800/-33-LUC. Transfection of pCx32-800/-33-LUC resulted in a 200-fold increase in luciferase activity above p19LUC in the human hepatoma cell line HuH-7. Using a series of vectors containing 5' deletions of the 760 bp fragment, a basal promoter was localized between -179 bp and -134 bp. Three DNA:protein complexes were identified with the basal promoter fragment by DNA mobility shift assay using nuclear extracts from HuH-7 cells. Two of the DNA-binding complexes appeared to be related to the transcription factor Sp1. In addition, three DNase hypersensitive (HS) sites were identified within the genomic locus of connexin32 in adult rat liver. Two of the DNase HS regions behaved as silencer elements with both the native promoter and a heterologous promoter in HuH-7 cells. These data demonstrate that (1) the active promoter responsible for rat connexin32 mRNA transcription is located upstream of the first exon, (2) a basal promoter region was localized to a 50 bp region which formed multiple DNA:protein complexes, and (3) multiple proximal and distant regulatory elements are involved in the expression of connexin32.

Animals↗
PubMed1993

Effect of caval-portal shunt on ovarian tissue in rats: I. Histological observation.

Forty-three female Sprague Dawley rats were divided into five groups, with groups 1-4 subjected to end-to-side caval-portal shunt (CPS). In addition to CPS, group 1 (n = 13), group 2 (n = 10), and group 3 (n = 7) rats had undergone removal of the right ovary and one-half of the left ovary, the left ovary, and one-half of the left ovary, respectively. Group 4 (n = 6) rats were not subjected to ovariectomy. Group 5 (n = 7) animals were not subjected to CPS but underwent left ovarian hemiresection. The ovarian volume of the hemiresected ovaries increased to 393.00 +/- 4.83 mm3 and 126.00 +/- 44.3 mm3 from 18.40 +/- 0.54 mm3 and 18.40 +/- 0.59 mm in groups 1 and 3, respectively, at the end of three postoperative months. The nonresected ovaries enlarged to 339.98 +/- 5.09 mm3 and 226.3 +/- 46.2 mm3 from 36.79 +/- 1.09 mm3 in groups 2 and 3, respectively. When no ovaries were resected, the CPS animals in group 4 showed an increment of ovarian volume of 1.75-2.2 times as much as the preoperative ones. In the animals that had undergone simple hemiovariectomy (group 5), the contralateral ovaries showed a significant increase in volume (40.2 +/- 8.3 mm3 to 243.1 +/- 114.8 mm3) at 3 months. The hemiresected ovarian volume increased from 27.1 +/- 5.5 mm3 to 44.1 +/- 11.8 mm3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[An observation of the anticarcinogenic effect of mitoxantrone-polybutylcyanoacrylate-nanosperes].

This paper reports the result of an experiment on the anticarcinogenic effect of liver targeted drug delivery system-mitoxantrone-polybutylcyanoacrylate-nanospheres (DHAQ-PBCA-NS) by using a model of heterotopic and orthotopic transplantation of human hepatocellular carcinoma (HCC) in nude mice. No significant difference was noted between the anti-HCC effects of mitoxantrone and dexerubicin, but the anti-orthotopic transplanting HCC effect of mitoxantrone-nanospheres was obviously higher than that of mitoxantrone and dexerubicin by comparison of tumor inhibition rates and proliferating cell nuclear antigen (PCNA). The result showed the applicability of mitoxantrone-nanospheres.

Animals↗
PubMed1993

[A model of orthotopic transplantation of human hepatoma established in nude mice tumor inhibition studies].

We established a model of orthotopic transplantation of human hepato-carcinoma. The tissues from human hepatoma LTNM4 were surgically implanted into the livers of 32 BALB/c nu/nu nude mice. These led to the development of tum or masses in the livers of 31 nude mice; the rate of success was about 96.8% (31/32). Furthermore, this model was applied to the studies on the tumor inhibitory action of DHAQ-PBCA-NS, a hepatic targeting preparation for anticarcinoma. Satisfactory effect was attained. The result has proved the applicability of this animal model to researches on hepatic targeting preparations against carcinoma.

Animals↗
PubMed1992

Nucleotide sequence of the extracellular alpha-amylase gene in the yeast Schwanniomyces occidentalis ATCC 26077.

The Schwanniomyces occidentalis (formerly castellii) ATCC 26077 (CBS 2863) alpha-amylase (AMY 26077) gene was cloned in Saccharomyces cerevisiae and sequenced. An open-reading frame encoding the AMY consists of 1536 base pairs and contains 512 amino-acid residues, which is almost the same in size as the AMY of Sch. occidentalis ATCC 26076 and CCRC 21164. The amino-acid sequence of AMY 26077 differed from that of ATCC 26076 alpha-amylase (AMY 26076) at two residues and from that of CCRC 21164 alpha-amylase (AMY 21164) at three residues. Comparison of the AMY 26077 gene with its homologues from two other strains (Sch. alluvius CBS 1153 and Sch. persoonii CBS 2169) using several restriction enzymes revealed that the AMY 26077 was very similar to AMY CBS 1153 but different from that of CBS 2169.

Amino Acid Sequence↗
PubMed1990

Arterialization of the liver. II. Systemic pressure gradients in rats following variously sized arteriovenous fistulae.

Four groups (I, II, III, and IV) of six Wistar rats each were studied to elucidate the blood pressure changes following creation of arteriovenous fistulae (AVF) of diameters 1, 2, and 3 mm (groups II, III, and IV, respectively). Group I comprised normal rats with no AVF. Blood pressures were recorded in the carotid and femoral arteries, the femoral and portal veins, the right atrium, and the inferior vena cava (IVC) at renal vein (RV) and common iliac vein (CIV) levels. We found that AVF size did not disturb baseline carotid arterial or portal venous pressures (P greater than 0.01), but the femoral arterial pressures fell increasingly (P less than 0.01). On the other hand, right atrial pressure and that of IVC at RV and CIV levels rose substantially with increasing diameters of AVF (P less than 0.01). It was concluded that an AVF of 1 mm diameter least upset the normal blood pressures in the vessels examined.

Animals↗
PubMed1990

Arterialization of the liver. III. Influence of systemic and portal pressure gradients following heterotopic partial liver transplantation.

An acute study was designed to compare blood pressures across a heterotopically transplanted partial liver graft using arterialized and nonarterialized models. Eight partial liver transplants (PLT) were done in each group, using Wistar rats. The data gathered from them are the basis for the results obtained herein. Whereas there was no significant difference (P greater than 0.01) in inflow, outflow, or the pressure difference across the PLT between nonarterialized and arterialized groups, host portal venous pressures were significantly higher (P less than 0.01) in the arterialized group. A 1 mm arteriovenous fistula (AVF) was used to arterialize the PLTs in this study. It was proved that arterializing a PLT using a 1 mm AVF did not alter the pressure difference across the transplanted liver compared with the situation in the nonarterialized setting.

Animals↗
PubMed1989

Effect of arteriovenous fistula size on arterialized and host livers in rats.

In studying the hemodynamic relationship and behavior of peak blood flow indexes at different sizes of arteriovenous fistulas (AVF) using arterialized partial liver transplants (PLT), 96 male Wistar rats served as donors and recipients of heterotopic PLT in an acute phase study using ether anesthesia. AVF of 1, 2, and 3 mm were compared with a control group (0 mm) along the "index of peak perfusion rate" of blood flow, the dependent variable. We found that with increasing AVF sizes, a progressive fall in the peak blood flow in the host livers (P less than 0.01, r = -0.51) and a similar rise in the same index in the graft livers (P less than 0.01, r = +0.76) were documented. Also noted was a gradual fall in the cardiac pulsatility component of perfusion to both host and graft livers at AVF sizes of 2 and 3 mm. The same component of perfusion to host and graft livers was best at AVF size of 1 mm. It was concluded that a 1-mm AVF provided the best degree of arterialization to a PLT.

Animals↗
PubMed1987

Sufentanil disposition during cardiopulmonary bypass.

In order to investigate the ability of a computer-assisted continuous infusion (CACI) system to maintain constant plasma levels of sufentanil during cardiopulmonary bypass (CPB) using pharmacokinetic data derived from healthy surgical patients to determine the infusion rate, ten patients were anaesthetized with diazepam, enflurane and oxygen until ten minutes prior to the expected time of initiation of CPB. At that point, an infusion of sufentanil, aimed to reach a central compartment concentration of 5 ng.ml-1, was started via CACI. Plasma concentrations of sufentanil, haematocrit, total protein and albumin concentrations, and nasopharyngeal and CPB inflow temperatures were obtained at predetermined intervals before and up to 90 min after the initiation of CPB. Plasma concentrations of sufentanil reached 3.8 +/- 0.4 ng.ml-1 before CPB and approached the 5.0 ng.ml-1 set point (4.7 +/- 0.4 ng.ml-1) over the 90 min of CPB. In conclusion, our results show that it is possible to obtain stable plasma levels of sufentanil on CPB using a pharmacokinetically driven infusion scheme; however, our data suggest that use of such a system may lead to accumulation of drug during CPB.

Aged↗
PubMed1987

Effects of preoperative calcium entry blocker therapy on alpha-adrenergic responsiveness in patients undergoing coronary revascularization.

Calcium entry blocking drugs (CaEBs) produce vasodilation and, in high doses, modify alpha adrenergic receptor function. Previous laboratory data suggested that CaEBs might alter the response to alpha-adrenergic stimulation. The authors tested the hypothesis that CaEB therapy altered alpha-adrenergic responsiveness in patients chronically treated with CaEBs. Twenty-six consenting patients with coronary artery disease were given a phenylephrine challenge before anesthesia induction and during cardiopulmonary bypass while the aorta was cross-clamped. A log dose response curve was constructed for each patient, and the ED30 (dose producing 30% increase in systemic vascular resistance) was calculated. Nine patients not treated with CaEB served as controls, and 17 patients were treated with nifedipine (n = 7) or diltiazem (n = 10). Mean ED30 was increased approximately three-fold in the CaEB treated groups compared to the control group. However, there was no statistical difference in the ED30 or phenylephrine dose response slopes between CaEB treated and untreated patients. In awake patients, ED30 correlated with nifedipine levels (R = 0.953, P = 0.01). There was a significant (P less than .02) shift in the ED30 from prior to anesthesia to during aortic cross-clamp and cardiopulmonary bypass; ED30 was approximately 50% less and correlated with CaEB level (R = 0.713, P = 0.03). Hemodynamic variables were not different between groups at any interval. Our data suggest that vascular responsiveness to phenylephrine in patients treated with CaEBs is diminished, but similar to that in untreated patients. Vascular responsiveness decreases in awake patients with increasing nifedipine levels.

Adult↗
PubMed1987

Regulation of bovine adipose tissue metabolism during lactation. 3. Adaptations of hormone-sensitive and lipoprotein lipases.

Activity of lipases in adipose tissue during pregnancy and lactation was investigated in Holstein cows producing 5950 to 10,000 kg milk per 305 d. Activity of cytoplasmic lipoprotein lipase per gram of tissue was 97, 78, 140, 162, 179, and 235% of 30 d prepartum at -15, 15, 30, 60, 180, and 349 d about calving in yr 1. In yr 2, lipoprotein lipase per gram was 100, 259, 838, 791, and 430% of -30 d at -15, 30, 60, 120, and 180 d. Adaptations in activity per milligram cytoplasm protein were similar to those per gram tissue. Hormone-sensitive lipase per milligram protein was 161, 251, 114, 126, and 252% of -30 d when measured at 30, 60, 120, 180, and 240 d postpartum. Activity per gram of tissue responded similarly to the lactation state. Lipoprotein lipase is thus not a large contributor to the peripartum bovine adipose adaptation but is important in reattainment of body composition in mid and late lactation. Hormone-sensitive lipase is also increased during peak and midlactation. The pattern of elevated activity of these oppositely directed lipases reflects the dichotomous forces of milk fat production and body fat recovery acting on adipose tissue of lactating heifers.

Adipose Tissue↗
PubMedDate not supplied

Characterization of a rapid and sensitive enzyme immunoassay (EIA) for progesterone applied to conditioned cell culture media.

Progesterone accumulation in conditioned media is a frequently employed endpoint for in vitro cell culture of steroidogenic cells. Although radioimmunoassay (RIA) has been the predominant method for measurement of progesterone, a number of nonradiometric immunoassays have been described but they have not been applied to conditioned media. Here, we report the characterization of a microtitre plate enzyme immunoassay (EIA) for determination of progesterone in conditioned media. The EIA has a sensitivity of 0.3 pg per well with intraassay and interassay coefficients of variation of 7.3 and 10.2%, respectively. The specificity of the EIA is no different than that of a comparable RIA showing crossreactivities of less than 0.1% for other steroids except 5 alpha-pregnan-3,20-dione (47%) and 11 alpha-hydroxyprogesterone (18%). Progesterone levels from conditioned cell culture media of either rat or human granulosa cell cultures measured by both EIA and RIA were in close agreement (r = 0.96) and serial dilutions of culture samples in the EIA were parallel to those of the standards. Also, extraction of culture media prior to EIA was found not to be necessary. Thus, this EIA is a highly sensitive and specific assay that provides a rapid, simple, inexpensive, and non-radiometric alternative to radioimmunoassay for measurement of progesterone in conditioned cell culture media.

Animals↗
PubMedDate not supplied

Orthodromic reciprocating tachycardia and heart failure in a dog with a concealed posteroseptal accessory pathway.

A 4-month-old male Labrador Retriever was presented for recurrent bouts of pulmonary edema associated with tachycardia. Initial physical examination and echocardiography were unremarkable, and the electrocardiogram revealed only an intraventricular conduction disturbance. Subsequent recordings showed paroxysmal supraventricular tachycardia (SVT) (340 beats/min), which consistently produced pulmonary edema. The supraventricular tachycardia was unresponsive to adenosine, esmolol, and propranolol; was variable and transiently responsive to various vagal maneuvers and precordial thumps; and was always responsive to IV diltiazem. Multiple life-threatening episodes of SVT occurred, however, despite the chronic administration of oral diltiazem, propranolol, and procainamide. Diastolic cardiac dysfunction was documented by Doppler echocardiography and was thought to contribute to the development of pulmonary edema. A subsequent electrophysiologic study confirmed the presence of an atrioventricular posteroseptal accessory pathway that participated in orthodromic reciprocating tachycardia. This pathway was determined to conduct only in the retrograde direction ("concealed accessory pathway"). Intraoperative IV procainamide titration terminated the arrhythmia, which could not be reinduced when procainamide blood concentration approximated 20 micrograms/dL. Increasing the oral procainamide dose to achieve such plasma concentrations was successful in eliminating orthodromic reciprocating tachycardia, preventing heart failure, and returning Doppler indices of diastolic function to normal.

Animals↗
PubMedDate not supplied

Effects of some natural products as components of Chinese herbal medicines on mammary gland growth and function in mice.

As a possible step to evaluate the role in the mammary glands of the scales of Guanshanjia, the fruits of Lulutong and the seeds of Wangbuliouxing, which are the natural products used widely as the components of herbal medicine in China for the improvement of lactation and the therapy of breast disorders, the effects of these agents on mammary gland growth and function were studied in female mice. The chronic administration of each agent in drinking water improved several parameters; however, the mode of action differed markedly among agents. The results indicate the necessity of acquiring enough knowledge of the characteristics of each agent for the efficient prescription of herbal medicine as well as the single use of the agent.

Animals↗