Analysis of the secondary structure that negatively regulates inducible cat translation by use of chemical probing and mutagenesis

Induction of chloramphenicol (Cm) acetyltransferase-encoding genes (cat) by Cm has been proposed to result from the destabilization of a stem-loop that sequesters the ribosome-binding site for the cat coding sequence. Destabilization is caused by the stalling of a ribosome at a specific site in the leader of cat transcripts that immediately precedes the stem-loop. By use of in vivo dimethylsulfate probing of cat-86 leader mRNA, we demonstrate the existence of the stem-loop structure in cat transcripts isolated from uninduced cells and its release during induction. Leader mutations chosen to provide the mRNA with an alternative folding pattern that destabilizes the stem-loop cause constitutive cat expression. Our results establish the occurrence in vivo of the stem-loop in cat-86 transcripts and its role as a negative regulator of cat expression.

Generation of multiple drug resistance by sequential in vitro passage of the human immunodeficiency virus type 1

We have sequentially passaged both laboratory and clinical isolates of the human immunodeficiency virus type 1 (HIV-1) in MT-4 cells in the presence of increasing concentrations of different drugs to derive viral variants that are multiply resistant to various combinations of ddC, ddI, d4T and AZT. The EC50 values obtained for the viruses thus generated varied between 50-100 times above those of parental wild-type strains in the case of AZT, 20-30 times for d4T, but only 10-15 times for ddI and ddC. Cultivation of AZT-resistant viruses in the presence of increasing concentrations of ddI yielded viruses that were resistant to the latter compound, with no apparent decrease in susceptibility to AZT. Sometimes, viruses selected for resistance against ddI were cross-resistant as well against ddC, although most viruses selected for resistance to ddC were not cross-resistant to ddI. Combinations of two or three of these compounds inhibited replication of HIV variants that displayed resistance to the same drugs when tested individually. No emergence of drug resistance was demonstrable when combinations of drugs were employed simultaneously in these selection protocols or when single drugs were used in concert with interferon-2 alpha or high dilutions of virus-neutralizing antisera. Cloning and sequencing of some viruses resistant to each of AZT, ddI, and ddC revealed the simultaneous presence of mutations at sites 41, 74, 184 and 215 within the HIV pol gene open reading frame.

DNA damage induced p53 mediated transcription is inhibited by human papillomavirus type 18 E6

Cervical cancer is similar to other human cancers in that it develops through a multistep process. However, infection with oncogenic human papillomaviruses (HPVs) is believed to be essential for the initiation of this disease. Although HPV may play a central role in the early stages of neoplasia, the accumulation of mutations in an assortment of genes precedes the development of malignant cervical carcinoma. The mechanisms by which abnormalities accumulate are various, but it is possible that viral proteins are involved. In particular, the viral E6 oncoprotein has been shown to interact with the cellular tumour suppressor protein p53, which is involved in DNA damage repair pathways. Hence, E6 may contribute to the genomic instability through this interaction with p53. We have tested this hypothesis by monitoring the effects of E6 upon DNA damage induced p53 transcriptional activity. This study shows that HPV-18 E6 inhibits p53 transcriptional activity following genotoxic stress with UV radiation. No effect was observed when a mutant E6 unable to direct the degradation of p53 was included in this assay. These results suggest that continued E6 expression may contribute to the accumulation of DNA damage associated with the progression of cervical cancer.

Identification of a mutation at codon 65 in the IKKK motif of reverse transcriptase that encodes human immunodeficiency virus resistance to 2',3'-dideoxycytidine and 2',3'-dideoxy-3'-thiacytidine

The technique of in vitro selection was used to generate variants of the human immunodeficiency virus type 1 that are resistant to 2',3'-dideoxycytidine (ddC). Most of the pol regions of such viruses, including the complete reverse transcriptase open reading frame and portions of flanking protease and integrase genes, were cloned and sequenced, using PCR-based procedures. Mutations were variously detected at amino acid site 65 (Lys-->Arg; AAA-->AGA) and at a previously reported codon, site 184 (Met-->Val; ATG-->GTG). We introduced the site 65 mutation into the pol gene of infectious, cloned HxB2-D DNA by site-directed mutagenesis in order to confirm by viral replication assay the importance of this site in conferring resistance to ddC. The recombinant virus possessed greater than 10-fold resistance against this compound in comparison with parental HxB2-D. Cross-resistance of approximately 20- and 3-fold, respectively, was detectable against the (-) enantiomer of 2',3'-dideoxy-3'-thiacytidine and 2',3'-dideoxyinosine but not against 3'-azido-3'-deoxythymidine. Combinations of the site 65 and 184 mutations did not yield levels of resistance higher than those attained with the site 65 mutation alone. The presence of the site 65 mutation was confirmed by PCR analysis of peripheral blood mononuclear cells from patients on long-term ddC therapy in 4 of 11 cases tested. Viruses that possessed a ddC resistance phenotype were isolated from subjects whose viruses contained the site 65 mutation in each of four instances. Four of these clinical samples were also demonstrated to possess the Met-184-->Val mutation, and one of them possessed both the Lys-65-->Arg and Met-184-->Val substitutions. Direct cloning and sequencing revealed the site 65 mutation in viruses isolated from these individuals.

[Experimental analysis of mechanism concerning the environmental temperature effect on acquisition of capability in toad oocyte to resume meiotic division]

Full-grown oocytes derived from Bufo bufo gargarizans rearing in high temperature environment (28-30 degrees C), called high temperature oocytes, never underwent germinal vesicle breakdown (GVBD) after progesterone stimulation, no MPF was detected in their ooplasm, but some events which manifested normally at the beginning of progesterone induced maturation process were revealed in these oocytes. It is worth notice an another kind of maturation promoting substance(s) appeared in the ooplasm of high temperature oocyte after the hormone treatment, which was capable of triggering the resumption of meiotic division of the full-grown oocytes derived from hibernating toad (called low temperature oocytes). It is a hibernation factor-dependent maturation promoting substance (HF-MPS), which appeared after decrease of the oocyte endogenous cAMP level. Its appearance depended upon the oocyte protein synthesis, and its activity to inducing GVBD of low temperature oocytes did not inhibited by puromycin. HF-MPS differs from MPF in maturation promoting activity, as low temperature (10 degrees C) delayed obviously HF-MPS' activity but did not influence the rate of GVBD induced by MPF. Further more, probably due to the lack of "hibernation factor(s)", no expression of p34cdc2 gene was detected in high temperature oocytes (unpublished data), neither HF-MPS nor MPF could amplify autocatalytically in the oocytes. So the low temperature (below 15 degrees C) was found to be indispensable for the toad oocyte maturation. If one day we can prove HF-MPS appeared also in the course of oocyte maturation induced by progesterone, the relationship between HF-MPS and MPF may be: [formula: see text] All these discoveries indicated above make a reasonable explanation of the geographical distribution of the toad which was restricted in the region north to the 23 degrees north latitude and east to the 100 degrees east longitude in China.

[Emancipation of the developmental block of early rat embryos by protein factors excreted from rabbit oviduct epithelial cells in culture]

Experiments were designed to evaluate the ability of rabbit oviduct epithelial cells (ROEC) or ROEC conditioned medium to promote the development of rat eggs fertilized in Vivo or in Vitro. 61.73% of the eggs fertilized in Vitro and 73.33% of the eggs fertilized in Vivo cocultured with ROEC overcame the 2-cell block (Plate I, tables 1 and 2). Similarly, 67.99% of the eggs fertilized in Vitro cultured in ROEC conditioned medium developed over the 2-cell stage, and nearly half of them developed to morula and blastocysts stage (Table 3). By using 35S-methionine incorporation and autoradiography methods, several polypeptides, with molecular weight of 135 Kd, 68 Kd, 55 Kd, 51 Kd and 44 Kd respectively (Fig. 1), were excreted from rabbit oviduct epithelial cells and found in the ROEC conditioned medium. The possibility of entrance of the ROEC proteins into the developing embryo was tested by determining whether any of the secreted proteins bound to the zona pellucida. The results of iodination by using 125I-containing acylating agent labelling method showed that the 68 Kd and 55 Kd proteins were bound onto the zona pellucida of rat eggs co-cultured with ROEC in vitro for 24 h (Fig. 2). Studies concerning the problem that whether these two secreted proteins are the key factors to promote the development of early embryos and the transition of maternal to zygotic control of embryo development are undertaking.

Molecular basis of cystathionine beta-synthase deficiency in pyridoxine responsive and nonresponsive homocystinuria

Cystathionine beta-synthase (CBS) deficiency is an autosomal recessive disorder associated with multisystem clinical disease. We analyzed PCR amplified products from patients' RNA and genomic DNA. Direct sequencing of the entire coding region of the CBS gene revealed a G-919 to A transition in exon 8, resulting in replacement of Gly 307 by Ser (G307S) in the protein. The mutation was detected in one allele of patient L171 of French/Scottish ancestry and in both alleles of patient L198 of Irish ancestry. Amplifying and sequencing exon 8 from the genomic DNA showed that both parents of L198 were heterozygotes for G307S. The pathogenicity of the mutation was demonstrated in an expression experiment. The mutant protein was apparently stable in E.coli extracts and lacked catalytic activity. Sequencing of exon 8 revealed the G307S mutation in five additional families. All patients have pyridoxine nonresponsive homocystinuria. We have now observed this mutation in 9 of 52 apparently unrelated alleles of varied ethnic backgrounds. All 9 are from patients with Celtic (Irish/English/Scottish/French) ancestry in either one or both parents. The G307S mutation was detected in 50% (9 of 18) of the Celtic alleles in our series. The second mutation found in exon 8 is the I278T mutation, which was described previously in one allele of a pyridoxine responsive patient. This missense mutation was detected in one allele of a pyridoxine nonresponsive patient and in both alleles of a pyridoxine responsive patient. The latter suggests that I278T is probably associated with pyridoxine responsiveness.

Peptidyl transferase inhibition by the nascent leader peptide of an inducible cat gene

The site of ribosome stalling in the leader of cat transcripts is critical to induction of downstream translation. Site-specific stalling requires translation of the first five leader codons and the presence of chloramphenicol, a sequence-independent inhibitor of ribosome elongation. We demonstrate in this report that a synthetic peptide (the 5-mer) corresponding to the N-terminal five codons of the cat-86 leader inhibits peptidyl transferase in vitro. The N-terminal 2-, 3-, and 4-mers and the reverse 5-mer (reverse amino acid sequence of the 5-mer) are virtually without effect on peptidyl transferase. A missense mutation in the cat-86 leader that abolishes induction in vivo corresponds to an amino acid replacement in the 5-mer that completely relieves peptidyl transferase inhibition. In contrast, a missense mutation that does not interfere with in vivo induction corresponds to an amino acid replacement in the 5-mer that does not significantly alter peptidyl transferase inhibition. Our results suggest that peptidyl transferase inhibition by the nascent cat-86 5-mer peptide may be the primary determinant of the site of ribosome stalling in the leader. A model based on this concept can explain the site specificity of ribosome stalling as well as the response of induction to very low levels of the antibiotic inducer.

Expression, purification, and RNA-binding properties of HIV-1 p15gag nucleocapsid protein

We have cloned and expressed HIV-1 gag p15 nucleocapsid protein (NCp15) in the form of a 41-kDa fusion polypeptide with glutathione-S-transferase (GST-NCp). The recombinant protein was rapidly degraded in bacterial lysates unless Zn2+ and Cd2+ were present in the extraction buffer. Inclusion of these metals stabilized the protein, allowing facile purification of GST-NCp by affinity chromatography. The native NCp15 was readily prepared from GST-NCp by proteolytic cleavage with thrombin. Both GST-NCp and the processed NCp15 were able to bind RNA containing sequences from the 5'-end of the HIV-1 genome. This binding was unaffected by the absence or the presence of Zn2+; however, the binding of RNA was absolutely dependent on the presence of K+. The GST-NCp fusion protein was nonselective in the binding of RNA, with all transcripts, including antisense and non-HIV RNA, binding with equal efficiency. In contrast, NCp15 was highly selective in binding of RNA. Sequences within nucleotides 1244-1412 of the HIV-1 proviral genome were found necessary for maximal binding of RNA to NCp15.

The same mutation that encodes low-level human immunodeficiency virus type 1 resistance to 2',3'-dideoxyinosine and 2',3'-dideoxycytidine confers high-level resistance to the (-) enantiomer of 2',3'-dideoxy-3'-thiacytidine

Variants of human immunodeficiency virus type 1 that display 500- to 1,000-fold resistance to the (-) enantiomer of 2'-deoxy-3'-thiacytidine and approximately 4- to 8-fold resistance to 2',3'-dideoxycytidine and 2',3'-dideoxyinosine have been generated through in vitro selection with the former compound. The polymerase regions of several of these resistant viruses shared a codon alteration at site 184 (ATG-->GTG; methionine-->valine), a mutation previously associated with low-level resistance to 2',3'-dideoxycytidine. The biological relevance of this mutation for the (-) enantiomer of 2'-deoxy-3'-thiacytidine was confirmed by site-directed mutagenesis with the HXB2-D clone of human immunodeficiency virus type 1.

[Effects of air pollution on health of residents in vicinity of an electrometallurgical factory in Chengdu]

Air pollution in an electrometallurgical plant in Chengdu was monitored in 1988. Results showed that atmospheric TSP and Ni concentrations in the vicinity of the plant were higher than those in control area; and TSP content higher than its health standard level. A population of 262 children was physically examined in the same pollution and control areas in May, 1988. Physical examinations were as follows:otorhinolaryngological examination, skin patch test of Ni and Co, immune function test (including PHA skin test, salivary LZM content), Ni levels in human hair and urine etc. We found that body burdens of Ni in population of pollution area increased because of the pollution of Ni compounds in the atmosphere. Hair Ni content in pollution area was significantly higher than that in control area, and the positive rate of Ni skin patch test was also markedly higher than that in control area. Case history indicated that there was a significant difference in Ni content as detected by otorhinolaryngological examinations between the pollution and control areas. Some measures were suggested to improve the air quality based on the study.

Parallel induction strategies for cat-86: separating chloramphenicol induction from protein synthesis inhibition

Induction of cat-86 translation results from the stalling of a ribosome at a discrete location in the leader region of the transcript. Stalling destabilizes an adjacent region of secondary structure that sequesters the cat-86 ribosome binding site, thereby activating cat-86 translation. Two well characterized antibiotics, chloramphenicol and erythromycin, induce cat-86 by stalling a ribosome at the appropriate leader site. Here we demonstrate differences between the two antibiotics with respect to induction. First, induction by chloramphenicol is dependent on nucleotides in the leader sequence that are different from those necessary for erythromycin induction. Second, variants of Bacillus subtilis that are chloramphenicol resistant because of chromosome mutations permit cat-86 induction by chloramphenicol, whereas erythromycin-resistance host mutations block or greatly reduce cat-86 induction by erythromycin. Third, selected strains of B. subtilis bearing alterations in proteins of the 50S ribosomal subunit interfere with cat-86 induction by chloramphenicol, yet these strains are chloramphenicol sensitive. Lastly, induction by chloramphenicol is not reversed by removal of the antibiotic whereas erythromycin induction is reversible. The data indicate that chloramphenicol induction results from an effect of the drug that is not identical to its role as a general inhibitor of ribosome elongation. Induction by erythromycin, on the other hand, could not be distinguished from its antibiotic activity.

Generation of drug-resistant variants of human immunodeficiency virus type 1 by in vitro passage in increasing concentrations of 2',3'-dideoxycytidine and 2',3'-dideoxy-3'-thiacytidine

We selected in vitro human immunodeficiency virus type 1 variants that are resistant to each of 2',3'-dideoxycytidine (ddC) and the racemic mixture of 2',3'-dideoxy-3'-thiacytidine (BCH-189). The median effective concentrations of ddC and BCH-189 obtained for the resistant viruses ranged between 10 and 50 times above those for parental wild-type strains, and extensive cross-resistance was observed against 2',3'-dideoxyinosine (ddI) but not 3'-azido-3'-deoxythymidine (AZT). Two dimer compounds, in which either AZT and ddI or AZT and BCH-189 were linked through phosphodiester linkages, did not permit the emergence of variants resistant to BCH-189, ddI, or AZT but were ineffective at inhibiting the replication of AZT-resistant viruses.

Novel mutation in the human immunodeficiency virus type 1 reverse transcriptase gene that encodes cross-resistance to 2',3'-dideoxyinosine and 2',3'-dideoxycytidine

We have used the technique of in vitro selection to generate variants of human immunodeficiency virus type 1 (HIV-1) that are resistant to 2',3'-dideoxyinosine (ddI) and cross-resistant to 2',3'-dideoxycytidine (ddC). The complete reverse transcriptase (RT)-coding regions, plus portions of flanking sequences, of viruses possessing a ddI-resistant phenotype were cloned and sequenced by polymerase chain reaction (PCR)-based methods. We observed that several of these viruses possessed mutations at amino acid sites 184 (Met-->Val; ATG-->GTG) and 294 (Pro-->Ser; CCA-->TCA). These mutations were introduced in the pol gene of infectious, cloned HXB2-D DNA by site-directed mutagenesis. Viral replication assays confirmed the importance of site 184 with regard to resistance to ddI. The recombinant viruses thus generated displayed more than fivefold-greater resistance to ddI than parental HXB2-D did. Moreover, more than fivefold-greater resistance to ddC was also documented; however, the recombinant viruses continued to be inhibited by zidovudine (AZT). No resistance to ddI, ddC, or AZT was introduced by inclusion of mutation site 294 in the pol gene of HXB2-D. PCR analysis performed on viral samples obtained from patients receiving long-term ddI therapy confirmed the presence of mutation site 184 in five of seven cases tested. In three of these five positive cases, the wild-type codon was also detected, indicating that mixtures of viral quasispecies were apparently present. Viruses possessing a ddI resistance phenotype were isolated from both subjects whose viruses contained only the mutated rather than wild-type codon at position 184 as well as from a third individual, whose viruses appeared to be mostly of the mutated variety.

NIP1, a gene required for nuclear transport in yeast

Cytochrome c with a nuclear localization signal added at the N terminus was mistargeted to the nucleus, resulting in a yeast strain deficient in mitochondrial cytochrome c. Reversion of this strain allowed the isolation of temperature-conditional mutants defective in nuclear transport, as demonstrated with one of these mutants, nip1-1, that was shown to be defective in nuclear accumulation of a LacZ protein containing a nuclear localization signal of the yeast ribosomal protein L29. The NIP1+ gene was cloned and shown to encode a 93,143-Da protein. Furthermore, an epitope-labeled NIP1 protein migrated in SDS/polyacrylamide gels with a mass of approximately 100,000 Da and was shown by immunofluorescence to localize mainly in the cytoplasm. NIP1+ was shown to be an essential gene by gene disruption experiments. Intriguingly, NIP1 has a serine-rich acidic N-terminal region that is similar in this regard to the N-terminal region of a previously described nuclear localization signal-binding protein, NSR1.

Nucleolin forms a specific complex with a fragment of the viral (minus) strand of minute virus of mice DNA

Nucleolin, a major nucleolar protein, forms a specific complex with the genome (a single-stranded DNA molecule of minus polarity) of parvovirus MVMp in vitro. By means of South-western blotting experiments, we mapped the binding site to a 222-nucleotide motif within the non-structural transcription unit, referred to as NUBE (nucleolin-binding element). The specificity of the interaction was confirmed by competitive gel retardation assays. DNaseI and nuclease S1 probing showed that NUBE folds into a secondary structure, in agreement with a computer-assisted conformational prediction. The whole NUBE may be necessary for the interaction with nucleolin, as suggested by the failure of NUBE subfragments to bind the protein and by the nuclease footprinting experiments. The present work extends the previously reported ability of nucleolin to form a specific complex with ribosomal RNA, to a defined DNA substrate. Considering the tropism of MVMp DNA replication for host cell nucleoli, these data raise the possibility that nucleolin may contribute to the regulation of the parvoviral life-cycle.

Perturbing highly conserved spatial relationships in the regulatory domain that controls inducible cat translation

Chloramphenicol activates translation of cat-86 mRNA by stalling a ribosome in the leader of individual transcripts. Stalling triggers two sequential events: the destabilization of a region of secondary structure that sequesters the cat ribosome-binding site (RBS-C), and the initiation of cat translation. The site of drug-dependent ribosome stalling is dictated by the leader sequence, crb; crb causes a ribosome to stall with its aminoacyl site at leader codon 6. We demonstrate that induction requires the maintenance of a precise spatial relationship between crb and sequences within the left inverted repeat of the secondary structure. Therefore, destabilization of the secondary structure during chloramphenicol induction may result from the interaction of a stalled ribosome with a specific sequence in the secondary structure rather than from non-specific masking of RNA sequences. cat-86 regulation also depends on the distance that separates crb from RBS-C. This interval of 33 nucleotides was incrementally increased and decreased by mutations within a loop in the secondary structure. Shortening the distance between crb and RBS-C by three nucleotides reduced induction by half and a deletion of nine nucleotides abolished induction. Insertion mutations were without effect on induced expression but elevated basal expression. The results indicate that when the A site of a ribosome occupies leader codon 6 the secondary structure is destabilized and there is no interference with entry of a second ribosome at RBS-C. The data further demonstrate that when the A site of a ribosome in the leader is within 30 nucleotides of RBS-C, cat expression decreases. This decrease probably results from competition of the leader ribosome with the ribosome initiating cat translation. Our observations demonstrate that in wild-type cat-86 the distances between crb and the secondary structure, and between crb and RBS-C provide the precise spacing necessary to achieve three interdependent effects: the destabilization of the RNA secondary structure by a ribosome stalled at crb; a lack of competition between a ribosome stalled at crb and the initiating ribosome; and maintenance of a low, but measurable, basal level of cat expression. The spatial relationships identified as necessary for the regulation of cat-86 are conserved in the regulatory regions for five other inducible cat genes.

[Application of Bayes discriminatory analysis to malaria stratification in Hainan province]

The present study was conducted to explore a new method for stratification of malaria endemicity. Several socioeconomic and geographic factors deemed appropriate to be employed in association with malaria epidemic potential were deal with Bayes discriminatory analysis.55 local villages in 12 counties of Hainan province were selected for socioeconomic survey, among which 33 villages were taken as the modelling sample and 22 villages were the non-modelling sample. The questionnaire contained a total of 12 relevant items. After socioeconomic inquiry was performed, the data were analysed through Bayes discriminatory theorem. Six important factors ware selected, i.e. topography (X1), proportion of labour forces (X4), income per person (X5), house structure (X8), knowledge of malaria control (X10), frequency of over-night stay in mountain forest (X12). Three discriminatory function formulas referring respectively to hyper-, meso-, and hypo-endemicity were set up. These 3 discriminatory function formulas were further applied to fit the endemicity of 33 model-sampling villages and 22 non-model-sampling villages. The agreement rate were 91.0% and 77.3% respectively.

Diagnostic exploration of enlarged peripheral nerves in suspected cases of leprosy. An analysis of 55 cases

In 55 cases presenting with enlarged peripheral nerves without any skin lesions, a rice grain-sized biopsy of the nerve lesion was taken for histopathological examination. As a result definitive diagnoses could be established: leprosy was diagnosed in 32 cases. In 23 cases the cause of nerve enlargement was not leprosy: post-traumatic neuritis 9, cysts 5, hypertrophic neuritis 3, nonspecific 4, neurofibroma 1, and amyloidosis 1. In all of these cases there was a deficit of the nerve function and postoperatively there were no complications. The authors, as a result of this experience, believe that surgical exploration and biopsy is a harmless diagnostic tool for establishing a definitive diagnosis of leprosy in cases presenting with enlarged peripheral nerves without any skin lesions. In 23 out of 55 such cases the nerve enlargement was proved to be other causes than leprosy.

[A new method of identifying Chinese crude drugs by comparing the characteristic content patterns of their chemical constituents]

Using the characteristic patterns of contents of chemical constituents, Chinese crude drugs derived from closely relative species and their fakes can be clearly identified and the quality of these drugs can be roughly evaluated. In this paper, the identification of Qianghuo (Notopterygium spp.) was presented based on this new method.

Observation of the activity of factor VIII in the endometrium of women pre- and post-insertion of three types of IUDs

The endometrial materials were obtained from 90 women who had been randomly inserted with three types of IUDs (Stainless steel ring, SS; copper T 220, TCu 220, and levonorgestrel-releasing device, LNG). An immunoperoxidase reaction, PAP method, with the antiserum of Factor VIII as the primary antibody, was carried out to detect the Factor VIII activity in the endometrial endothelium pre- (control) and post-insertion of the IUDs. The results revealed that: 1. There was a generalized lower Factor VIII activity in the endometrium of women post-insertion of IUDs (except LNG). 2. Comparison of the Factor VIII activity in the endometrium of women using different types of IUDs showed that the TCu type and the SS type decreased the activity significantly whereas the activity remained unchanged after 3-6 months' use of the LNG-IUD. The different types of IUDs seemed to influence the coagulation regulatory system in different ways; the lower Factor VIII activity, the more tendency to bleeding. 3. The Factor VIII activity in the endometrium of women using IUDs was lower in all phases of the menstrual cycle including the proliferative phase when the Factor VIII activity is normally high. It cannot be excluded that this could be a contributing factor to IUD-induced bleedings.

[Signal multiplier spectrophotometric determination of baicalin, chlorogenic acid and phillyrin in shuang huanglian injection]

Signal multiplier spectrophotometry was used for the determination of baicalin, chlorogenic acid and phillyrin in Shuang Huanglian injection. The method can eliminate interference without preliminary separation and has proved simple, speedy and accurate.

[Clinical study of superoxide dismutase in recurrent aphthous ulceration]

Activity of superoxide dismutase (SOD) was determined in erythrocytes obtained from 74 patients with recurrent aphthous ulcerations (RAU) and 100 healthy individuals. The results showed that activity level of SOD in RAU was significantly lower as compared with that in the controls (P less than 0.01). The activity of SOD in 30 cases of RAU at interval period was elevated on reexamination, but it was still lower than that in the controls (P less than 0.01). There is evidence that damage of superoxide radicals (O.2) and decrease of activity of SOD may play important roles in the pathogenesis of RAU. A random double-blind, placebo-controlled, cross-over trial on membrane SOD was carried out in 40 patients with RAU. The results demonstrated that the effective rate of SOD was 90%, being markedly higher than that of placebo. It is suggested that membrane SOD, as a topical medicine, could increase the concentration of SOD on the ulcerous surfaces, prevent O.2-induced injury, decrease capillary permeability, relieve inflammation and improve cure of ulcer.

[Pharmacognostical studies on the ethnic substitutes of duzhong derived from Euonymus spp]

Macro-and microscopic characters were observed on the more popular ethnic substitutes of dutzhong derived from 21 species of Euonymus (Celastraceae). A chart of major characters and a key to each species are given.

Observation of the activity of factor VIII in the endometrium of women with regular menstrual cycles

An immunoperoxidase reaction was used to detect Factor VIII activity in the endometrial endothelium during the normal menstrual cycle. Fifty-three women of fertile age, having regular menstrual cycles, participated in the study. Endometrial material was obtained from 33 women in the preovulatory phase and from 20 women in the post-ovulatory phase. The immunoperoxidase reaction was evaluated using a scoring system. Cyclic changes related to the pre- and post-ovulatory phase were observed in the Factor VIII activity of the endometrial endothelial cells; a gradual increase occurred from the early to the late proliferative phase and thus activity gradually decreased during the secretory phase. No activity was observed in the late secretory or in the menstrual phase.

The effect of intrauterine injection of concanavalin A on implantation in mice and rats

Concanavalin A (Con A) binding sites are present on the surface of blastocysts. When Con A was injected into one uterine horn of the mouse on Day 3 or 5 of pregnancy at 50 or 100 micrograms/horn, or given to the rat on Day 6 or 7 at 200 micrograms/horn, implantation and pregnancy was not affected when compared to the contralateral horn treated with vehicle alone. However, when the same amount of Con A was administered to the mouse on Day 4 or to the rat on Day 5, implantation was significantly decreased, all accompanied by the incidence of deciduomata. The deciduogenicity of Con A is dose-dependent. Also Con A did not affect the development of mouse embryos as a normal number of blastocysts was recovered up to the time of implantation. Thus the inhibition of implantation by Con A could be due to (a) the earlier occurrence of decidual cell response and its subsequent interference with implantation and (b) the involvement of specific sugar groups in implantation.

The uptake and release of benzo[a]pyrene and benzo[e]pyrene in vitro by Syrian hamster embryo cells as a function of serum concentration

A quantitative study on the in vitro uptake of benzo[a]pyrene (B[a]P) and benzo[e]pyrene (B[e]P) by Syrian hamster embryo cells and the induction of sister chromatid exchange (SCE) has been carried out. The amounts of B[a]P and B[e]P taken up by the cells decreases as does the induction of SCEs by B[a]P when the concentration of serum in the culture medium increases. It appears that serum prevents (B[a]P or B[e]P uptake. We have observed no significant differences between the two hydrocarbons regarding uptake by cells; chromatographic results show however that B[a]P is metabolized by these cells, while B[e]P is not. Our results suggest that serum inhibits B[a]P and B[e]P uptake and hence decreases the number of SCEs.

Effects of Gossypol on the fertility of male rats, hamsters and rabbits

Oral administration of Gossypol acetic acid induced sterility in male hamsters and rats when given at a dose level of 5 or 10 mg/kg daily for 12 weeks. This was shown by the appearance of dead and abnormal sperm in the male tract and the failure of pregnancy or decrease in implantation sites in the females mated to the Gossypol-treated males. Similar treatment of male rabbits at dose levels varying from 1.25 to 10 mg/kg and given for 5 to 14 weeks did not affect the average number of sperm per ejaculate, although the motility of sperm was poor during treatment in some bucks. The pregnancy rates and the proportion of implantation sites were also not affected by insemination of female rabbits with sperm from males during treatment with Gossypol.

A-nor steroids as post-coital contraceptives in the hamster with special reference to the transport and degeneration of eggs

Two A-nor steroids, Anordrin and H241, showed a marked antifertility effect when given orally to hamsters at 10 mg/kg/day for three or four days after mating. Further study indicated that the antifertility effect was due to a disturbance of egg transport, retarded development and degeneration of fertilized eggs.