Biomedical subjects
Publications and source records attributed to L F Wang.
Acute toxicity and LD50 of 62 mineral drugs were determined by ig, ip or iv in mice, in order to provide some guidelines for safety in clinical use, as well as for pharmacological and toxicological studies. In the present investigation, the difference in the acute toxicity and LD50 between raw drugs and medicines prepared by roasting is explained.
With improvements in cardiac monitoring systems and the effective treatment of arrhythmias, the case-fatality rate of acute myocardial infarction (AMI) has been declining gradually since 1972. But since 1977, despite the great efforts of medical workers in many countries, the lowest case-fatality rate of AMI has still been about 10%. Over many years, our institute has carried out research aimed at improving the treatment of AMI. However, in our institute the case-fatality rate has fluctuated between 15 and 20% in recent years. From March 1986 to January 1987 we adopted a sodium nitroprusside and dopamine intravenous drip in the treatment of 92 cases of AMI and achieved a hospitalization period AMI case-fatality rate of less than 5% (2 patients died). The treatment methods and relevant materials are reported here.
In a double-blind study, 0.5% tetracaine 10 mg in hyperbaric or isobaric solution was administered intrathecally at random to 102 adult patients. Except the variable under study, identical technique was used for every patient enrolled. Other influential factors were also under careful control. The extent and pattern of anesthesia were compared. The time for maximal spread was short, the mean times was 7.74 min and 7.8 min for hyper-and isobaric groups respectively, there was no differences statistically. (P less than 0.05). The maximum cephalad spread was T5 (mean, range T12-T3) for the hyperbaric solution and T7 (mean, range T10-T3) for the isobaric solution. The difference was 2 dermatomes and was statistically significant (P less than 0.01). Forty three patients (86%) in the hyperbaric group and 16 patients (30%) in the isobaric group had a sensory blockade higher than T6 level. The hyperbaric group has a much higher percentage of high blockade. The isobaric group has a more predictory lower blockade, but occasionally blockade up to T3 did occur. The 2-segment regression times were also statistically significant. That of hyperbaric group was 88.9 min (mean, range 60-150 min) and 180.5 min (mean, 75-270 min) in isobaric group with a P value less than 0.01. Statistically significant differences in regard to maximum motor blockade and its onset times were found between the two groups. Maximum motor blockade assessed by modified Bromage scale was degree 2 (mean, range 1-3) for the hyperbaric group and degree 3 (mean, range 2-3) for the isobaric group.(ABSTRACT TRUNCATED AT 250 WORDS)
Using the signal peptide of the Bacillus subtilis subtilisin gene (aprE) and a synthetic cDNA corresponding to the mature region of the human atrial natriuretic alpha-factor (hANF), we have constructed a secretion vector. B. subtilis cells, when transformed with this vector, secrete immunoreactive hANF peptides into the medium at about 500 micrograms/liter. The hANF is the first human gene product to be secreted from B. subtilis using this signal peptide. We have used promoters active during vegetative growth or sporulation and hosts deficient in several extracellular proteases but some proteolysis of the secretion products still occurs. In addition, both cell growth and sporulation are adversely affected by hANF production. Possible explanations for this observation are inefficient secretion of the atrial hormone or toxicity of the precursor or mature peptide.
A unicellular algae, Chlorella pyrenoidosa, was used as a biological response modifier. In C57BL/6(B6), C3H/He and DDD/1 mice, both intraperitoneal or oral administrations of autoclaved Chlorella cells or heat-extracted substance were carried out every other day for 10 days before mouse mammary carcinoma (MM-2) or Ehrlich ascites cells were transplanted into the peritoneal cavity. In case of mouse leukemia cells (EL-4), subcutaneous transplantation was carried out. All control mice died within 20 days after each tumor cell transplantation, while 73.3-80% of the treated groups survived over 60 days in the combination of MM-2 vs. C3H/He and EL-4 vs. B6, respectively. The cytotoxic activities against tumor cells, that were abolished by treatment with anti-Thyl.2 monoclonal antibody plus complement, were evidenced in the experimental host. Since Chlorella cells and derivatives showed no indication of direct in vitro cytotoxicity to either tumor or mouse spleen cells, the antitumor effects documented may be mediated by host immune response.
A new 'Bacillus natto' gene, senN, that regulates the expression of several extracellular proteins in B. subtilis has been cloned and sequenced. senN codes for a small, highly basic protein with an amino acid sequence different from the products coded by the regulatory genes sacQ, sacV, prtR and hpr. SenN stimulates gene expression at the transcriptional level. A putative homologous locus has been detected in the B. subtilis chromosome by Southern blotting.
Three promoters direct transcription of the sigA (rpoD) operon in Bacillus subtilis. Promoters P1 and P2 are used during the exponential growth phase, whereas P3 is used only during the stationary phase. We examined the use of these promoters in promoter-probe plasmids and found that expression from P3 was prevented by a mutation in spoOH, which encodes the secondary RNA polymerase sigma factor sigma H. Moreover, we found that sigma H-containing RNA polymerase efficiently and accurately used the P3 promoter in vitro. Evidently, this operon, which is essential for exponential growth, is transcribed during the early phase of sporulation by this secondary form of RNA polymerase. Comparison of the nucleotide sequences of the P3 promoter and the spoVG promoter, which also is used by sigma H-RNA polymerase, revealed sequences at the -10 and -35 regions of these promoters that may signal recognition of promoters by sigma H-RNA polymerase.
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Sequencing data indicated that the RNA polymerase sigma 43 operon of Bacillus subtilis consisted of three genes, P23 (function unknown), dnaE (DNA primase), and rpoD (sigma 43) (Wang and Doi 1986a). S1 nuclease mapping experiments with RNA from various stages of growth demonstrated the presence of two overlapping sigma 43 promoters that controlled the expression of the operon during growth and a sigma 37 promoter that regulated the expression of the operon during the sporulation phase. This promoter switching mechanism ensured that this important operon would be expressed during different nutritional states of the cell and also illustrated a function for the minor RNA polymerase sigma 37 holoenzyme in the expression of genes which are normally expressed during the logarithmic phase of growth. The location of the transcription termination signal confirmed that the sigma 43 operon consists of three genes.
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Airway obstruction remains a constant problem in acute care. This is particularly true when there are anatomical or pathological abnormalities, trauma, or when repeated failed attempts at endoscopic or blind intubations have left a bloody field, preventing clear visualization of the vocal cords. Our refinement of translaryngeal guided intubation (TLI) uses a spring guidewire accompanied by a plastic sheath protector. The wire is introduced percutaneously via a cricothyroid puncture and passed cephalad into the oropharynx or nasopharynx and out through the mouth or one of the nostrils. The plastic sheath is slid over the wire into the trachea. A well-lubricated endotracheal tube is then inserted to the desired position using the plastic sheath as a stylet. This technique works very well, and we are convinced that TLI is one of the most effective emergency techniques to secure an airway. It can be performed quickly with inexpensive equipment and is a promising addition to the currently recommended alternatives.
The first gene of the Bacillus subtilis RNA polymerase sigma 43 operon, P23, has a protein-coding capacity of 23,000 daltons. Sequence analysis revealed three potential translational initiation sites within the same reading frame, which could encode proteins of 23,000 (P23), 19,000 (P19), and 9,000 (P9) daltons, respectively. An internal promoter (P3), which is expressed only during the sporulation stage, is located between the second and the third translational start sites. By protein fusion to the Escherichia coli beta-galactosidase gene, we showed that all three translational initiation sites of the P23 gene are used in vivo in both E. coli and B. subtilis, and regulation for differential expression of the three proteins during the development of B. subtilis is coupled to the transcriptional promoter switching mechanism. The physiological function of these multiple gene products is unknown and is currently under investigation.
A monoclonal antibody (MAB) interacting with human sperm was purified by ammonium sulfate fractionation and gel filtration on Sephadex G-200. The MAB designated as YWK-II belongs to the IgM class and is composed of mu heavy chains and kappa light chains. The MAB localized to the equatorial region of the sperm head, midpiece, and tail. The sperm antigen interacting with the YWK-II MAB was purified by immunoaffinity chromatography on Sepharose 4B conjugated with YWK-II antibodies. Two interacting proteins, estimated Mr of 60 and 72 kD, were identified.
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The gene coding for Bacillus subtilis RNA polymerase major sigma 43, rpoD, was cloned together with its neighboring genes in a 7 kb EcoRI fragment. The complete nucleotide sequence of a 5 kb fragment including the entire rpoD gene revealed the presence of two other genes preceding rpoD in the order P23-dnaE-rpoD. The dnaE codes for DNA primase while the function of P23 remains unknown. The three genes reside in an operon that is similar in organization to the E. coli RNA polymerase major sigma 70 operon, which is composed of genes encoding small ribosome protein S21 (rpsU), DNA primase (dnaG), and RNA polymerase sigma 70 (rpoD). There is a relatively high degree of base and amino acid homology between the DNA primase and sigma genes. The most significant differences between the two operons are observed in the molecular size of the first genes (P23 and rpsU), the complete lack of amino acid homology between P23 and S21, the molecular weights of the two rpoD genes, the size of the intercistronic region between the first two genes, and the regulatory elements of the operon.
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