Investigation on the carcinogenic effects of coal tar pitch in rat respiratory tract by intratracheal instillations

The effects of coal tar pitch (CTP) on the tracheobronchial mucosa of Wistar rats were studied. Three groups of animals received 10 weekly intratracheal instillations of CTP at the cumulative doses of 6.48, 136.56 and 200 mg respectively. The control group of rats received 10 weekly intratracheal instillations of charcoal powder at a cumulative dose of 20 mg. The study in which the animals were killed serially revealed that CTP had conspicuous damage on the respiratory system of rats, especially on the bronchiolo-alveolar areas. The lesions induced by CTP ranged from hyperplastic, metaplastic and dysplastic changes to extensive cancers. These lesions were usually multifocal, and were more severe in the rats receiving higher dosages of CTP. The deposition of CTP particles within or adjacent to these lesions could be readily identified. Lung cancers occurred in 12.5% (4/32) and 25% (10/40) of the rats treated with 136.56 and 200 mg of CTP, whereas no tumors were found in control rats and the rats that received 6.48 mg of CTP. The overall cancer incidence significantly related to the cumulative dose of CTP. The histological types of lung cancers consisted of squamous cell carcinomas (10 out of the 14 lung cancers), adenocarcinoma (1/14), and combined squamous and adenocarcinomas (3/14). The development of CTP-induced rat lung cancers appears to derive from the hyperplasias of bronchiolo-alveolar epithelium, and processing stages of squamous metaplasias and/or dysplasias to carcinomas. The present results confirmed the carcinogenic effects of CTP on the respiratory system of rats, and provided experimental evidence for human lung carcinogenesis, particularly in those occupationally exposed to coal tars or tar products.

X-Ray Diffraction Evidence for Nonstoichiometric Rubidium-C 60 Intercalation Compounds

Powder x-ray diffraction at 300 K on equilibrated samples of several nominal compositions chi in Rb(chi)C(60) is reported. In addition to the face-centered cubic (fcc) (chi = 3, superconducting), body-centered tetragonal (chi = 4), and body-centered cubic (bcc) (chi = 6) stoichiometric phases, direct evidence for a dilute fcc doped phase, 0 x c </= 1, and for a substoichiometric bcc phase, chi approximately 5, is presented. In contrast, chi = 3 and chi = 4 appear to be line phases with nearly zero solubility of Rb vacancies and interstitials at 300 K. These results are summarized in a provisional binary phase diagram.

The role of oxygen free radicals in myocardial ischemia/reperfusion injury

A series of experiments have been done to investigate the role of oxygen free radicals in ischemia/reperfusion injury. The following results were found: Myocardial MDA content increased significantly after post-ischemic reperfusion in vivo and in vitro. A blockade of the xanthine oxidase pathway for free radical generation could provide effective protection against ischemia/reperfusion injury. Exogenous reactive oxygen intermediates H2O2, .OH and O2- could induce changes in the contractility and electrophysiological properties of myocardial cells similar to those seen in ischemia/reperfusion. An outburst of free radical generation was detected by ESR spectroscopy at low temperature (-173 degrees C) and with the spin trapping technique during the very early phase of reperfusion. The authors emphasize the important role of free radicals in the pathogenesis of myocardial ischemia/reperfusion injury.

[An approach to removing stains and remineralization of dental fluorosis]

341 mottled teeth were bleached with 4% and 18% hydrochloric acid; the mixture of 36% hydrochloric acid, 30% hydrogen peroxide and anesthetic ether; and 30% hydrogen peroxide warmed by infra-red ray lamp. The effects were evaluated clinically. The extracted mottled and normal teeth were treated with the methods mentioned above. The decolouration effects, the structural changes of tooth surface, and the remineralization were examined by scanning electronmicroscopy and polaroid microscopy. The results showed: all of the four methods had the decolouration effects; the decolouration effect was better in the teeth with higher mineralization and the pigmentation existed more superficially; complete decolouration was 94.8% and lightened cases were 5.2%. The mechanism of decolouration seemed to be the dissolution of tooth superficial layer containing pigment. The decalcified tooth surface might be recalcified by the treatment of recalcification solution, or by saliva itself.

Maternal-fetal transmission of SIV in macaques: disseminated adenovirus infection in an offspring with congenital SIV infection

To develop a nonhuman primate model for maternal-fetal transmission of HIV infection, we have inoculated pregnant Macaca nemestrina with uncloned SIVMne. Three animals inoculated during the third trimester delivered healthy infants. One of the three infants, a male born 31 days after the mother was inoculated with SIV, became virus-positive but failed to produce SIV-specific antibody and died with overt simian immunodeficiency and disseminated adenovirus (SV20) infection at age six and one-half months. SIV and adenovirus antigen could be demonstrated by immunohistochemical methods in multiple organ systems.

Isolation and characterization of a rice gene encoding a basic chitinase

Chitinase, which catalyzes the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine linkages of the fungal cell wall polymer chitin, is involved in inducible defenses of plants. A basic chitinase genomic sequence was isolated from a rice (Oryza sativa L.) genomic library using a bean chitinase gene fragment as a probe. The complete nucleotide sequence of the rice chitinase RCH10 gene was determined, and shown to contain an open reading frame with no introns, encoding a polypeptide of 336 amino acids. This polypeptide consists of a 21 amino acid signal peptide, a hevein domain, and a chitinase catalytic domain. The RCH10 gene has 63% identity at the nucleotide level and 75% identity at the amino acid level with chitinase genes from dicotyledonous plants such as bean, potato, and tobacco. A gene fusion of trpE and the coding region of RCH10 expressed in Escherichia coli gave a product that reacted with antiserum to bean chitinase, confirming the identity of RCH10 as a rice chitinase gene. Primer extension analysis identified two transcription start sites 53 bp and 55 bp upstream from the translation initiation codon. The 5' flanking region contains TATA and CAAT boxes, and the 3' region contains an AATAA polyadenylation signal. Southern blot hybridization indicated that there is a family of chitinase genes in the rice genome. Northern blot analysis showed that the RCH10 chitinase gene is induced in suspension cultured cells by a fungal cell wall elicitor. Rice chitinase transcripts accumulate to a high level in roots, but only low levels are found in stem and leaf tissue.

Corticostatic peptides

In the last four years corticostatic (anti-ACTH) peptides have been isolated from human, rabbit, guinea pig and rat tissues. These peptides do not act via the cAMP cell signalling system but rather via the inhibition of the binding of ACTH to its receptor most probably through direct competition with the 14-18 sequence of ACTH for receptor binding. ACTH has specific high affinity receptors on adrenal cells but rabbit corticostatin I (CSI) has high capacity, low affinity receptors which are competed for by unlabelled excess CSI but not by excess ACTH. This indicates the presence of specific CSI adrenal cell receptors. The rabbit pituitary, hypothalamus, thalamus, adrenals, lungs and placenta contain sizeable amounts of immunoassayable CSI. Immunochemical localization of CSI indicates that it is present in the large macrophages and in neutrophils in rabbit lung, in macrophages and "supporting" endothelial cells in the spleen and in the adrenals in the cells of the zona reticularis. We have also isolated and identified new peptides which contain 12 cysteines from immune cells of humans, rats and a teleost, the carp. The functions of these peptides are now being determined. This large family of peptides may have many other, yet unidentified functions but at present we can only describe a small number of these.

Diagnostic contrast echocardiography in children with congenital heart disease

905 diagnostic contrast echocardiographic studies (DCE) were performed on 223 children. Carbon dioxide microbubble was used as contrast agent in various age groups, especially in newborns and infants because of its safety in application, stable contrast effect, and peripheral vein injection. Two-dimensional echocardiography (2-DCE), a useful tool in diagnosis of left to right shunt lesions reduced false negative diagnoses for ventricular septal defects and eliminated false positive diagnosis for atrial septal defects and patent ductus arteriosus. The accuracy of diagnosis in this series was 97%. The results of this series showed that 2-DCE is also valuable in the diagnosis of congenital heart disease with right to left shunts, and can be used to evaluate shunt levels and determine the obstructive sites on the right side of the heart.

[Adenosine deaminase inhibitor (EHNA) on ischemia-reperfusion injury in isolated perfused rat hearts]

The effects of Erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) on Langendorff perfused rat hearts subjected to ischemia-reperfusion injury were studied. Results showed that EHNA can inhibit the increase of cardiac resting tension during ischemia period and decreasing the incidence of ventricular fibrillation and its duration. The contraction amplitude, resting tension and heart rate could be recovered to preischemic level, and the coronary flow even greater than before. The authors thought that EHNA can block the breakdown of adenosine to inosine and hypothanxine, and, therefore, cut off the pathway and production of oxygen free radicals during ischemia-reperfusion injury.

[Short-term curative effect of cultured Cordyceps sinensis (Berk.) Sacc. Mycelia in chronic hepatitis B]

33 cases of chronic hepatitis B. patients treated with cultured Cordyceps sinensis mycelia have shown that the drug improves the liver function, promotes negative transfer HBsAg, and markedly helps to raise plasma albumin, resist high gamma globulin and to adjust body immunocompetence. It is therefore suggested that cultured Cordyceps sinensis mycelia may be used as a medicine for chronic hepatitis B. patients in adjusting protein metabolism and correcting inversion of albumin and globulin.

[Quantification of pulmonary to systemic flow ratio (Qp/Qs) in children with patent ductus arteriosus by echocardiography]

The assessment of left-right ductal shunting flow in 35 children with PDA by 2-DCE with 35 normal children as a control was shown in the study. A close relationship was demonstrated between the grade of the diastolic negative contrast at the distal ends of the pulmonary artery and Q p/Qs. The diastolic negative contrast effect of 2-DCE could be used as a new important index in the assessment of left-to-right ductal shunting flow. Four parameters which were closely correlated with Qp/Qs were selected from 8 parameters by the stepwise multilinear regression procedure. The 4 parameters were grade II DNCE, LVPWER, grade I DNCE, LADR. A regression equation which was capable of assessing Q p/Qs noninvasively in children with PDA was derived from the 4 parameters. The accuracy of calculation of Qp/Qs by the regression equation was 80%.

[Component analysis of the extracellular polysaccharide from Mortierella hepiali Chen et Lu sp. nov]

The extracellular polysaccharide from the filtrate of fungal fermentation of Mortierella hepiali, a fungus isolated from traditional Chinese crude drug Cordyceps sinesis, is made up of three sugar components, glucose, mannose and galactose, which are detected by paper and gas chromatography. Both molar ratio and contents of the polysaccharide are determined by the internal standard method.

Isolation and biological activity of corticostatic peptides (anti-ACTH)

Corticostatins (CS's) are a family of low molecular weight peptides, rich in arginine and cysteine with the ability to inhibit ACTH stimulated adrenocortical steroidogenesis. They show a high degree of specificity in that they do not inhibit the action of angiotensin II in the adrenal cortex. Four corticostatins have been isolated from rabbit lung extracts and peritoneal neutrophil extracts and one from human neutrophils. Among them corticostatin I, CSI, is the most potent with an I.D.50 of 25 nM. Corticostatin activity is different from other published inhibitory factors such as TGF-B and ANF, which inhibit basal and angiotensin II stimulated steroidogenesis. Other factors such as macrophage secreted products, and septic shock plasma factors which have not been fully characterized also have suppressive activity on ACTH induced adrenocortical steroidogenesis in vitro. It is not yet clear whether there is any relationship between corticostatins and these macrophage products and shock plasma factor. Corticostatins do not inhibit dbcAMP induced steroidogenesis, however they do inhibit the accumulation of cAMP in response to ACTH in rat adrenal cell suspensions. Binding studies show that CSI is a competitive inhibitor of ACTH, probably acting by blocking, the address recognition site of the receptor. There is wide variation in the potency of the corticostatins ranging from an ID50 of 100 ng/ml for CSI to a completely inactive analog, HP1. In this paper we will describe the purification of the corticostatins and some recent results obtained on their mechanism of action.

[Luteinized unruptured follicle syndrome]

In a group of 109 infertile women, 180 cycles were monitored with B type ultrasound, BBT and cervical scoring. The incidence of LUF in stimulated cycles was 31.8%, significantly higher than that in spontaneous cycles (10.1%). During the follicular phase, no difference was found between the LUFS and normal ovulatory cycles as to follicular growth curve, maximal diameter of dominant follicle and the cervical scores. Therefore prediction of the LUFS is difficult. 63.6% of the LUF patients had recurrences, and high incidence of abnormality (70.6%) in their non-LUF cycles. 7 of the 14 patients with LUFS were originally diagnosed as unexplained infertility. It suggests that LUFS is of particular importance in the group of women with unexplained infertility.

Chemical crosslinking of glycoproteins on the envelope of herpes simplex virus

A base-reversible, 13-A homo-bifunctional chemical crosslinking reagent, bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone (BSOCOES), was tested for its ability to crosslink the herpes simplex virus type 1 glycoproteins associated with the envelope of purified virions. The crosslinked proteins were fractionated and analyzed by immunoblotting, immunoprecipitation, and two-dimensional polyacrylamide gel electrophoresis using monospecific antisera to detect the glycoproteins, gB and gC. Each of the glycoproteins exhibited distinct patterns of crosslinking. Monomers of gB were crosslinked and appeared as a high-molecular-weight complex. No apparent intermediates were observed between the gB monomer and the high-molecular-weight complex. Analysis of the components in the gB high-molecular-weight complex suggests that gB represents the major component and exists as a high-molecular-weight oligomer on viral envelopes under native conditions. In contrast, gC was cross-linked at a much lower efficiency and a number of components at intermediate molecular weights were detected. Initial studies on crosslinked products that were detectable with anti-gC antibody suggest that one of these products represents a gC dimer.