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Biomedical subjects

B Z Chen

Publications and source records attributed to B Z Chen.

At least 19 recordsLinked to original sources
PubMed2001

Crystallization and preliminary crystallographic studies of antibacterial polypeptide LCI expressed in Escherichia coli.

LCI is a type of novel antibacterial polypeptide secreted by a Bacillus subtilis strain. It consists of 47 residues with a molecular weight of 5468 Da. Using bioengineering, LCI was expressed in Escherichia coli DH5alpha with recombinant plasmid pBVAB16. It was crystallized using PEG 4000 as a precipitant. The crystal belongs to space group P6(2)22 or P6(4)22, with unit-cell parameters a = b = 29.30, c = 187.09 A, and diffracts to 2.44 A. A set of diffraction data to 2.8 A was collected.

Anti-Bacterial Agents↗
PubMed2001

Bipolar charged aerosol agglomeration and collection by a two-zone agglomerator.

In older to collect fine particles more efficiently, a new-type electrostatic agglomerator with two zones was developed. The distinguishing feature of this electrostatic agglomerator is that the particles are bipolarly charged and coagulated in the same alternating electric field simultaneously. The silica flour with 2 microns mass median diameter and the smoke from burning wood powder were used as test aerosol. The comparison experimental results have shown that when the mean electric field is 4 kV/cm the collection efficiency of the new electrostatic agglomerator was 98.2% for silica flour and 67.4% for wood powder smoke. Under the same experimental condition, the collection efficiency of the electrostatic agglomerator with three zones was 97.4% for collecting silica flour and the collection efficiency of the electrostatic precipitator was 56.3% for wood powder smoke.

Aerosols↗
PubMed1992

Effect of acute and chronic administration of ceronapril on angiotensin converting enzyme in plasma, kidney, lung, brain regions and cerebrospinal fluid of rats.

Angiotensin converting enzyme (ACE) in brain, cerebrospinal fluid (C.S.F.) and peripheral tissues was studied ex vivo after oral administration of ceronapril (SQ 29,852) to male Sprague-Dawley rats. Angiotensin converting enzyme in tissue was measured by in vitro autoradiography or enzymatic assay. In in vitro experiments, ceronapril inhibited ACE in slices of brain with an IC50 of approximately 34 nM, as measured by in vitro autoradiography. In C.S.F. ACE was inhibited with an IC50 of approximately 34 nM, as assessed by a fluorimetric enzyme assay. Ceronapril (100 mg/kg, p.o.) inhibited ACE in plasma, kidney and lung rapidly (3 hr) after administration. Inhibition of ACE in kidney lasted up to 48 hr after administration of ceronapril, whereas the activity of ACE in plasma and lung recovered rapidly (8 hr). In lung and plasma ACE was increased at 72 hr after administration. Therefore, induction of ACE in plasma and lung by the drug may partly obscure the acute inhibition and may contribute to the different time-course of inhibition of ACE from kidney. Ceronapril inhibited ACE in vascular organ of the lamina terminals (OVLT) and subfornical organ (SFO) of the brain slowly (onset at 8 hr) but persistently (from 24 to 48 hr). However the drug did not inhibit ACE in structures of the brain within the blood-brain barrier, such as the caudate-putamen, choroid plexus, globus pallidus, supraoptic nucleus and paraventricular nucleus of the hypothalamus. In C.S.F. ACE was not detectably inhibited by ceronapril but was increased at 72 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

[The dynamics of antigen and antibody in Schistosoma japonicum egg granuloma and its relationship with the granuloma response].

Synchronous Schistosoma japonicum egg granuloma in the lung of mouse model and PAP (peroxidas-anti-peroxidase) technique were employed to study the dynamics of antigen and antibody in the egg granuloma of S. japouicum and its relationship with the granuloma formation. The granulomatous response began on the 3.5 day after egg injection and increased to the maximal size at the 4th week. Lymphocyte populations and macrophage comprised an important part of lesions during the time of acute granulomatous response (7-28 day). Using PAP staining, the SEA within egg could be detected at high level on the first day after egg injection and then declined gradually. On the contrary, the SEA around egg was minimal at the first week and increased to the peak at the 4th week, then decreased gradually. No antibody could be detected throughout the experimental period (35 days). The results suggested that 1) the antigen of Schistosoma egg is the essential factor for the granuloma formation. 2) S. japonicum egg granuloma could be formed in unsensitized mouse. 3) The mechanism of egg granuloma formation of S. japonicum is similar to that of S. mansoni.

Animals↗
PubMed1990

Inhibition of angiotensin-converting enzyme (ACE) in plasma and tissue.

Inhibition of angiotensin-converting enzyme (ACE) in rat plasma and tissue was studied after administration of quinapril, a new orally active ACE inhibitor with an intermediate duration of action. Tissue and plasma ACE was assessed by a radioinhibitor-binding assay and by in vitro autoradiography using [125I]351A as the radioligand. Individual tissues in rats were differentially inhibited in time and degree. The highest ACE inhibition in plasma and in tissues occurred within the first 2 h after gavage treatment with quinapril, 0.3 mg/kg. After 24 h, ACE was still inhibited by 25% in plasma, by 30% in the aorta, by 35% in the kidneys, and by more than 40% in cardiac atria and ventricles. Plasma and kidney tissues showed increasing ACE inhibition in a dose-dependent manner after oral dosing with quinapril. In the brain, only the structures outside the blood-brain barrier were inhibited after the administration of 0.1 mg/kg of quinapril. Similarly, testicular ACE was unaffected by quinapril. These results demonstrate a prolonged effect of quinapril on tissue ACE and suggest that ACE inhibition in the heart, vasculature, and kidneys may be of particular importance in pathologic states such as hypertension or heart failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

Allogeneic fetal liver transplantation in acute leukemia.

Three patients with acute leukemia in first complete remission were transplanted with fetal liver cells from May 1983 to June 1984. A conditioning regimen of cyclophosphamide (60-80 mg/kg) and TBI 600-700 rads (a dose rate of 5-7r per minute) was taken. The hemopoietic and immunological recovery was rapid and complete in every patient. There was proof of chimerism in case 1 as demonstrated by the existance of the XX karyotype of donor fetus in 68.7% and 75% of marrow metaphases, in 25% of peripheral blood metaphases, by the appearance of new HLA-antigens and RBC blood type antigens of donor origin. The serum alpha-fetoprotein level increased and maintained for 40 days in case 2, but definite evidence of engraftment was not observed. The allogeneic marker, the donor's HLA-antigens and RBC isoenzyme, were detected in case 3.

Adolescent↗