Occupational allergy in the production of drugs

Quinazoline oxide--an intermediate in chlordiazepoxide synthesis--is the most potent contact allergen in the pharmaceutical industry. Penicillins proved to be potent allergens. Conditions of the technological process favor development of hypersensitivity to tetracyclines. No single case of allergy to erythromycin was noted. In case of employees hypersensitive to disulfiram and aminophylline cross reactions with compounds of similar structure were observed. The authors discuss also some problems concerning contact allergy in all persons occupationally dealing with various medicines.     

Antibiotic resistance study of clinical strains of Pseudomonas aeruginosa]

The study of 40 clinical strains of Ps. aeruginosa isolated from the wound surfaces of the patients showed that all the isolates were resistant to one or several antibiotics. The number of the strains resistant to 5, 4, 3, 2 or 1 drug was 5, 22.5, 25. 30 or 17.5 per cent respectively. Fifteen strains carried resistance plasmids capable of conjugative transfer. Eleven out of 21 plasmids controlled resistance to chloramphenicol, 7 plasmids controlled resistance to streptomycin and sulfanylamides, 1 plasmid controlled resistance to streptomycin and chloramphenicol. The presence of two types of the plasmids controlling resistance to chloramphenicol and streptomycin + sulfanylamides respectively was found. All the plasmids proved to be capable of conjugative transfer between the strains of Ps. aeruginosa ML (PAO). The frequency of the plasmid conjugative transfer in such crosses ranged from 10(-6) to 10(-3). Most of the plasmids belonged to the incompatibility groups P-2 and P-7. One plasmid belonged to the incompatibility group P-5. It should be noted that about a half of the plasmids (11 out of 21) belonged to the incompatibility group P-7 which up to the present time was conditional, since was represented by a single plasmid Rms 148.     

Thermodynamics,cooperativity and stability of the tetracycline repressor (TetR) upon tetracycline binding

Allosteric regulation of the Tet repressor (TetR) homodimer relies on tetracycline binding that abolishes the affinity for the DNA operator. Previously, interpretation of circular dichroism data called for unfolding of the α-helical DNA-binding domains in absence of binding to DNA or tetracycline. Our small angle X-ray scattering of TetR(D) in solution contradicts this unfolding as a physiological process. Instead, in the core domain crystal structures analyses show increased immobilisation of helix α9 and two C-terminal turns of helix α8 upon tetracycline binding. Tetracycline complexes of TetR(D) and four single-site alanine variants were characterised by isothermal titration calorimetry, fluorescence titration, X-ray crystal structures, and melting curves. Five crystal structures confirm that Thr103 is a key residue for the allosteric events of induction, with the T103A variant lacking induction by any tetracycline. The T103A variant shows anti-cooperative inducer binding, and a melting curve of the tetracycline complex different to TetR(D) and other variants. For the N82A variant inducer binding is clearly anti-cooperative but triggers the induced conformation.     

Broad antiviral activity and crystal structure of HIV-1 fusion inhibitor sifuvirtide

Sifuvirtide (SFT) is an electrostatically constrained α-helical peptide fusion inhibitor showing potent anti-HIV activity, good safety, and pharmacokinetic profiles, and it is currently under phase II clinical trials in China. In this study, we demonstrate its potent and broad anti-HIV activity by using diverse HIV-1 subtypes and variants, including subtypes A, B, and C that dominate the AIDS epidemic worldwide, and subtypes B', CRF07_BC, and CRF01_AE recombinants that are currently circulating in China, and those possessing cross-resistance to the first and second generation fusion inhibitors. To elucidate its mechanism of action, we determined the crystal structure of SFT in complex with its target N-terminal heptad repeat region (NHR) peptide (N36), which fully supports our rational inhibitor design and reveals its key motifs and residues responsible for the stability and anti-HIV activity. As anticipated, SFT adopts fully helical conformation stabilized by the multiple engineered salt bridges. The designing of SFT also provide novel inter-helical salt bridges and hydrogen bonds that improve the affinity of SFT to NHR trimer. The extra serine residue and acetyl group stabilize α-helicity of the N-terminal portion of SFT, whereas Thr-119 serves to stabilize the hydrophobic NHR pocket. In addition, our structure demonstrates that the residues critical for drug resistance, located at positions 37, 38, 41, and 43 of NHR, are irreplaceable for maintaining the stable fusogenic six-helix bundle structure. Our data present important information for developing SFT for clinical use and for designing novel HIV fusion inhibitors.     

Antibiotic resistance of Shigella in different regions of the USSR]

Shigella were most sensitive to polymyxin ceporin, ampicillin, neomycin and furazolidone and resistant to chloramphenicol, tetracycline and streptomycin. Shigella resistant simultaneously to two or three drugs mainly to tetracycline + chloramphenicol, tetracycline + streptomycin and tetracycline + chloramphenicol + streptomycin were most frequent. The frequency of the Shigella strains carrying R-plasmids increased from 28 per cent in 1969--1970 to 72.6 per cent in 1977. The Shigella strains isolated during the dysentery outbreak in 1973--1977 carried the R-factor controlling resistance to tetracycline + chloramphenicol, tetracycline + chloramphenicol + streptomycin, tetracycline + chloramphenicol + streptomycin + neomycin. Interaction between separate biochemical types, colicinogenicity and drug resistance classes was found in the Shigella isolates. The data on the effect of antibiotic (tetracyclines) intensive use in stock-raising defining wide spread of the R-plasmids controlling resistance to these drugs were obtained.     

Vibrion variability under the action of antibiotics]

Tetracycline, streptomycin and monomycin resistant variants of the cholera and NAG-vibrios were obtained by means of repeated passages on nutrient media with increasing concentrations of the antibiotics (114 variants V. cholerae asiaticae, 1337 variants of V. cholerae eltor and 299 variants of NAG-vibrios of the 1st Heiberg group). The highest number of the antibiotic resistant variants was obtained under the effect of streptomycin and the resistance level to it was much higher (up to 8000 gamma/ml) than that to tetracycline or monomycin (160 or 320 gamma/ml respectively). The study of the differential-diagnostic properties of the above vibrios showed that 14.8 per cent of the strains of V. cholerae asiaticae and 4.6 per cent of the strains of V. cholerae eltor became non-typical with respect to the colony morphology and fermentative properties. Their agglutinability with the species or type specific cholera sera partially decreased. Nine per cent out of 299 antibiotic resistant NAG-vibrios had changes only in the colony structure. None of them changed their fermentative properties or acquired even minor capacity for agglutination with cholera sera or lysing with specific bacteriophages. The described changes in the properties of the antibiotic resistant cholera and NAG-vibrios were not stable and disappeared after 2- or 3-fold passages on media containing no antibiotics.     

Interrelation of the enterotoxigenic properties and the antigenic structure of Escherichia

The enzymatic signs and serological characteristics of Escherichia enterotoxigenic strains isolated from patients with acute intestinal diseases and from healthy persons were studied. The cultures were subdivided into 24 enzymatic variants and classified with 48 serogroups and 61 serovars. The enterotoxigenic properties of the strains were compared with their serological characteristics and enzymatic signs. The strains, isolated from different persons and classified with the same serovar, belonged to the same variant with respect to the type of enterotoxin they produced (only thermostable enterotoxin, only thermolabile enterotoxin, or both), were similar in the degree of their toxigenicity and belonged, as a rule, to the same enzymatic variant. The data on the presence of manifest interrelation between the enteropathogenicity of Escherichia and their structure, as well as on the stability of the enterotoxigenic properties of these organisms, indicate that in acute intestinal diseases the determination of Escherichia enterotoxigenic strains can be carried out by common bacteriological techniques with the use of specific agglutinating sera.     

Antibiotics in the treatment of wounds in the victims of the earthquake in the Armenian SSR

Purulent wounds in 88 victims of the Armenian earthquake with the syndrome of long-term squeezing were examined microbiologically and the experience with using antimicrobial drugs for their treatment was analyzed. In all the cases microbial associations were detected, coliform and nonfermenting gram-negative bacilli, enterococci, anaerobes and yeast-like fungi being isolated from 80, 20, 15 and 25 per cent of the patients respectively. 130 bacterial strains were studied in detail. 80 to 100 per cent of the bacterial isolates were resistant to the antibiotics routinely used in surgical practice, i.e. benzylpenicillin, tetracycline, levomycetin, kanamycin, cephalothin and cefazolin and highly sensitive to new antimicrobial drugs belonging to ureidopenicillins (mezlocillin), quinolones (ciprofloxacin) and cephalosporins of the 3rd generation (cefoperazone and ceftazidime). Retrospective estimation of the antibiotic therapy revealed its inadequacy in 55.7 per cent of the patients for the most part because of the isolates resistance. The 19 variants of the antibiotic use prescribed by the physicians mainly included penicillins, aminoglycosides and their combinations (in 67.2 per cent of the cases). The use of the highly efficient drugs of the groups of ureidopenicillins and quinolones was extremely rare which was likely due to lacking of information on the drugs.     

Selection of colony, plasmid, and virulence variants of Staphylococcus epidermidis NRC853 during growth in continuous cultures exposed to erythromycin

A continuous-culture system was developed to study changes in the structure of Staphylococcus epidermidis populations exposed to subminimum inhibitory concentrations of erythromycin. Continuous-culture experiments were carried out in a dextrose-free, tryptic soy broth medium supplemented with lactic acid and sodium lactate (MTSB-D). The multiresistant (penicillin-, tetracycline-, and erythromycin-resistant) S. epidermidis strain NRC853 was subjected to a series of experiments: (i) growth individually in continuous culture in the absence and presence of erythromycin and (ii) growth in mixed culture with the erythromycin-susceptible S. epidermidis strain NRC852 in the absence and presence of erythromycin. Strain NRC853 produced colony morphology variants during continuous culture in the presence of 0.05 and 0.1 microgram of erythromycin per ml. Variants (A, B, and C) were different from their wild-type parent on the basis of colony size, sector pattern, and/or the ability to transmit light. A variants rapidly lost a 2.7-MDa tetracycline resistance plasmid. B and C variants formed an ermC plasmid multimer series from unit size to a 16-mer and exhibited an approximately twofold increase in erythromycin MIC over that of the wild-type parent. They slowly lost the tetracycline resistance plasmid. The small-colony B variant demonstrated an increased virulence in the neonatal mouse weight gain test and an increase in fibronectin binding compared with the wild-type parent. The presence of a competing strain drastically increased the frequency of all variants.     

Selection of colony, plasmid, and virulence variants of Staphylococcus epidermidis NRC853 during growth in continuous cultures exposed to erythromycin.

A continuous-culture system was developed to study changes in the structure of Staphylococcus epidermidis populations exposed to subminimum inhibitory concentrations of erythromycin. Continuous-culture experiments were carried out in a dextrose-free, tryptic soy broth medium supplemented with lactic acid and sodium lactate (MTSB-D). The multiresistant (penicillin-, tetracycline-, and erythromycin-resistant) S. epidermidis strain NRC853 was subjected to a series of experiments: (i) growth individually in continuous culture in the absence and presence of erythromycin and (ii) growth in mixed culture with the erythromycin-susceptible S. epidermidis strain NRC852 in the absence and presence of erythromycin. Strain NRC853 produced colony morphology variants during continuous culture in the presence of 0.05 and 0.1 microgram of erythromycin per ml. Variants (A, B, and C) were different from their wild-type parent on the basis of colony size, sector pattern, and/or the ability to transmit light. A variants rapidly lost a 2.7-MDa tetracycline resistance plasmid. B and C variants formed an ermC plasmid multimer series from unit size to a 16-mer and exhibited an approximately twofold increase in erythromycin MIC over that of the wild-type parent. They slowly lost the tetracycline resistance plasmid. The small-colony B variant demonstrated an increased virulence in the neonatal mouse weight gain test and an increase in fibronectin binding compared with the wild-type parent. The presence of a competing strain drastically increased the frequency of all variants.     

Independent regulation of two genes in Escherichia coli by tetracyclines and Tet repressor variants

We report a regulation system in Escherichia coli for independent regulation of two distinct reporter genes by application of Tet repressors with different specificities. One Tet repressor variant comprises wild-type tet operator (tetO) recognition and exclusive induction with the novel inducer 4-dedimethylamino-anhydrotetracycline. The other Tet repressor variant shows tetO-4C recognition and induction with tetracycline. We demonstrate that both variants are independently active in vivo and allow selective regulation of two genes in the same cell without any cross talk.     

A genetic analysis of variants of the human immunodeficiency virus type 1 (HIV-1) circulating among drug abusers in Moscow and Moscow Province

The genetic analysis of the variants of human immunodeficiency virus of type 1 (HIV-1), circulating among drug addicts in Moscow and Moscow Province, has been carried out. The serological analysis of 122 blood specimens taken from HIV-infected drug addicts, residing in Moscow and 22 settlements of the Moscow region, has shown that in this region HIV-1 variant of subtype A spreads among drug addicts. These data have been confirmed by the results of the analysis of 44 specimens, made with the use of the method of the heteroduplex mobility assay for gene env. As revealed in this study, HIV-1 variants spreading at present among drug addicts in Moscow and the Moscow region are genetically related to viruses of subtype A, detected earlier in this group of risk in other regions of Russia, the Ukraine, Belarus and other countries of Eastern Europe.     

Variants in the immune response to revaccination with diphtheria anatoxin in adults

The immunological effectiveness of the revaccination (made in two injections) of 488 adults aged 18-67 years with diphtheria-tetanus toxoid is discussed; the parallel study of the results of this revaccination was carried out in the diphtheria toxin neutralization test on Vero cells and in the passive hemagglutination (PHA) test. The specific features of the dynamics of the increase of diphtheria antitoxic antibodies, depending on the initial immunity level, the age and the sex of revaccinated persons, were determined. Among persons with the low level of circulating antibodies before revaccination four variants of immune response to the injection of diphtheria toxoid were registered: variant 1--rapid reaction like in secondary immune response (53.6%); variant 2--delayed but effective reaction like in primary immune response (27.3%); variant 3--slow weak response (6.5%); and variant 4--the absence of effective immune response to immunization made in 2-3 injections (12.6%). The immunological and neutralizing properties of diphtheria antitoxic antibodies in the process of immunization made in 2 injections were evaluated. Persons with abnormal immune response (variants 3 and 4) produced defective antibodies, displaying immunological activity in the PHA test, but in most cases unable to neutralize diphtheria toxin in vitro when tested on Vero cells.     

Sifuvirtide, a potent HIV fusion inhibitor peptide

Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC₅₀), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC₅₀) were relatively high, rendering it an ideal anti-HIV agent.A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1_IIIB were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF.In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.     

The oral neutrophil alteration test in drug allergy

Oral leukocyte alteration method was established for the diagnosis of drug allergy. This method is 68% positive in patients with drug allergy and 7% positive in healthy persons. The whole procedure is simple and takes only an hour and a half.     

Admixture in commercial tetracycline preparations

The content of admixtures in tetracycline stored under different conditions was determined with chromatographic and spectrophotometric methods. Biological activity, toxicity and colour of the drugs was tested. The changes in teh colour of tetracycline most pronounced on its storage at a temperature of 37 degrees C and elevated humidity were not accompanied by an increase in the content of anhydrotetracyclines. In parallel with the changes in the colour of tetracycline, the loss of its biological activity up to 30 per cent and increased toxicity were registered. The LD50 decreased by 40 per cent as compared to the initial level. Simultaneously an additional spot with high chromatographic mobility (Rf 0.98--1.0) was detected on thin-layer chromatograms. It was shown that the processes of tetracycline degradation resulting in marked darkening of the drug colour were not accompanied by an increase in the content of anhydro admixtures. They were probably the result of accumulation of other products which are as highly toxic and low active as the anhydroderivatives of tetracycline.     

Role of novelty seeking personality traits as mediator of the association between COMT and onset age of drug use in Chinese heroin dependent patients

BACKGROUND: Personality traits such as novelty seeking (NS) are associated with substance dependence but the mechanism underlying this association remains uncertain. Previous studies have focused on the role of the dopamine pathway. OBJECTIVE: Examine the relationships between allelic variants of the catechol-O-methyltransferase (COMT) gene, NS personality traits, and age of onset of drug use in heroin-dependent subjects in China. METHODS: The 478 heroin dependent subjects from four drug rehabilitation centers in Shanghai who were genotyped for eight tagging single nucleotide polymorphisms (SNP) on the COMT gene completed the NS subscale from the Temperament and Character Inventory. Multivariate analyses were used to assess the potential mediating role of NS personality traits in the association between COMT gene variants and the age of onset of heroin use. PRINCIPAL FINDINGS AND CONCLUSIONS: In the univariate analysis the COMT rs737866 gene variants were independently associated with both NS and age of onset of drug use: those with the TT genotype had higher NS subscale scores and an earlier onset age of heroin use than individuals with CT or CC genotypes. In the multivariate analysis the inclusion of the NS subscore variable weakened the relationship between the COMT rs737866 TT genotype and an earlier age of onset of drug use. Our findings that COMT is associated with both NS personality traits and with the age of onset of heroin use helps to clarify the complex relationship between genetic and psychological factors in the development of substance abuse.     

Investigation into use of drugs preceding death from asthma.

Copies of death certificates were provided by the Registrar General for all deaths attributed to asthma in persons aged 5 to 34 years which were registered in England and Wales in the last quarter of 1966 and the first quarter of 1967. Information was obtained from the relevant general practitioners about 177 of the 184 subjects, and necropsy data were obtained for 113 of the 124 cases in which a post-mortem examination was known to have been made. Ninety-eight per cent. of the subjects for whom evidence was obtained were known to have been suffering from asthma, and signs of severe asthma (overdistended lungs and small bronchi plugged with mucus) were found in 91% of necropsies (57% of all deaths). Evidence that death might have been due to any other pathological condition was rare. Death was sudden and unexpected in 81% of the subjects (137 out of 171), and 59% of all deaths were referred to coroners. In 39% of cases (67 out of 171) the practitioner had not regarded the patient as suffering from severe asthma in his terminal episode. Corticosteroids and sympathomimetic preparations were the only drugs to have been used by a large proportion of patients. Two-thirds of the patients had received corticosteroids before the terminal episode, but detailed information about their use provided no suggestion that excess use could have been responsible for any large proportion of the deaths. Eighty-four per cent. of the patients were known to have used pressurized aerosol bronchodilators, and several instances of their use in excess were described. Routine inquiries about their use in the hours immediately preceding death were not made, and further evidence is required before their effect can be assessed adequately.