Characterization of basal and re-inflammation-associated long-term alteration in pain responsivity following short-lasting neonatal local inflammatory insult.

Recently, several studies have suggested that neonatal noxious insult could alter future responses to painful stimuli. However, the manifestations, mechanisms, and even developmental nature of these alterations remain a matter of controversy. In part, this is due to the lack of detailed information on the neonatal sensitive period(s) during which noxious stimulation influences future nociception, and the time-course and distribution of the resultant abnormalities. The present paper describes these parameters in a rat model of short-lasting ( approximately 24 h) neonatal local inflammation of a hindpaw produced by injection of 0.25% carrageenan (1 microl/g). Examinations of paw withdrawal responses to thermal and mechanical stimulations in adult animals, which as neonates were subjected to this insult, showed that the previously-reported long-term hypoalgesia and hyperalgesia are not mutually exclusive outcomes of early noxious experience. Long-term hypoalgesia was apparent at the basal conditions and was equally strong in the previously injured and uninjured paws, which suggests a globally-driven deficit. In contrast, long-term excessive hyperalgesia had the strongest manifestation in the neonatally-injured paw after re-inflammation, indicating significant segmental involvement in its generation. The differences between mechanisms underlying the observed hypoalgesia and hyperalgesia are further underscored by the finding that, while the former is detectable only after animals reach the second month of life, the latter is elicitable immediately upon cessation of the initial neonatal inflammation. Nevertheless, we detected a significant overlap in the neonatal sensitive periods for generation of these effects (both occurring within the first postnatal week). Also, neither the basal hypoalgesia nor excessive re-inflammation-associated hyperalgesia subsided with age and were detectable in 120-125-day-old rats. These finding provide a framework within which the entire complex of long-term effects of early noxious experience can be understood and examined.

[Anion exchange chromatography of proteins leads to induction of DNA-binding activity in them]. / Anionobmennaia khromatografiia belkov privodit k induktsii v nikh DNK-sviazyvaiushchei aktivnosti.

The present work is devoted to investigation of the acquired DNA-binding activity of several proteins, such as bovine serum albumin, myoglobin, and collagens in different conformational states (native, denatured, and gelatin) following their anion exchange chromatography. Induction of DNA-binding activity, as shown, is natural phenomenon common in protein treatment on positively charged matrix. Obviously, anion exchange chromatography of proteins results in their structural conformational changes. It was suggested that the DNA-binding activity of activated proteins is based on the ability of the protein molecule to accept additional protons upon contact with the anion exchanger. This hypothesis is confirmed by the inhibition of the interaction of activated protein with DNA in the presence of Na-EDTA.

[Cloning of the structural gene for diphtheria toxin from Corynebacterium diphtheriae PW8 and expression of its deletion derivative in E. coli]. / Klonirovanie strukturnoi chasti gena difteriinogo toksina iz Corynebacterium diphtheriae PW8 i ékspressiia ego deletsionnogo proizvodnogo v E. coli.

The coding region of diphtheria toxin gene from Corynebacterium diphtheriae PW8 was cloned in Escherichia coli on pUC19 plasmid. 5' end of the gene was deleted. The deleted gene codes for a toxin like protein truncated for 36 N-terminal aminoacids. The modified gene was fused with 5' terminal part of the lacZ gene on pUC19 plasmid having kept the translational frame intact. The hybrid gene transcription depends on lacP promoter, Mr of the resulting toxoid is 54,000. The toxoid is devoid of ADP-ribosyltransferase activity peculiar for diphtheria toxin and thus is not toxic. The constructed version of the toxin gene can be used for production of diphtheria anatoxin which does not require to be inactivated by formalin.

[Cloning in Escherichia coli of the mutant gene coding the diphtheria toxin]. / Klonirovanie v Escherichia coli mutantnogo gena, kodiruiushchego difteriinyi toksin.

Bacteriophage beta 45 of Corynebacterium diphtheriae was harvested. The extracted DNA of the bacteriophage was digested by the restriction endonuclease BamHI and inserted into the BamHI cleavage site of pUC19 vector plasmid. Plasmid pNVY5 containing a mutant gene crm45 of diphtheriae toxin in a 3.9 bpn fragment was isolated from the hybrid plasmids obtained. Cell free extracts of E. coli strain TG1 (pVNY5) contain the nontoxic protein crm45 possessing the specific enzymatic activity of diphtheriae toxin (ADP ribosylation on wheat elongation factor two). According to orientation of BamHI fragment in pNVY5 plasmid it is concluded that the crm45 gene is expressed using its own promoter.

[Use of genetic and molecular characteristics of R plasmids as an epidemiological marker in an outbreak of hospital infection]. / Ispol'zovanie geneticheskoi i molekuliarnoi l kharakteristiki R-plazmid v kachestve épidemiologicheskogo markera pri vspyshke vnutribol'nichnoi infektsii.

Antibiotic sensitivity of 38 strains of enteric bacteria, such as Serratia marcescens Klebsiella pneumoniae and others and Ps. aeruginosa isolated during an outbreak of meningitis in a premature infant resuscitation department was studied. It was shown that all the isolates were multiple resistant, most frequently to 7 antibiotics. All the resistance markers were transferred on conjugation, segregation of some markers being observed. Investigation of the plasmid composition of the clinical strains and transconjugants of E. coli revaled the presence of 2 plasmids with the molecular weights of 40 and 60 Md or one of them. The restriction analysis demonstrated that the plasmids with the same molecular weights isolated from different strains were identical. It was suggested that such plasmids originated from the same source and were distributed by conjugation. The possible part of R plasmids in epidemiological analysis of hospital infections is discussed: the possible part as an additional marker in determination of the infection source and the possible part through its ability to change the host cell phenotype, including the phage and bacteriocin types.

[Possible dependence of the results of phage typing Ps. aeruginosa strains on the presence of R plasmids]. / Vozmozhnaia zavisimost' rezul'tatov fagotipirovaniia shtammov Ps. aeruginosa ot nalichiia R-plazmid.

The plasmid composition of 209 strains of Ps. aeruginosa was determined. The strains were isolated from patients, animals and environment in different geographical areas. The number of the plasmid-containing strains averaged 26.8 per cent. The molecular weights of the plasmids varied from less than 10 to more than 150 MD. 41 conjugative plasmids were transmitted to the recipients of Ps. aeruginosa RAO 303. 66 per cent of them had a restrictive effect on the development of phages used in genetic studies, epidemiological phage typing (Lindberg Collection), and medical practice. This resulted in the changing of the phage type of the host strain. Similar results were obtained in the studies with 10 standard R plasmids representing different incompatibility groups. No relation between the spectrum of the phage restriction, group specificity and the other properties of the plasmids was observed. About 50 per cent of the plasmids markedly lowered the sensitivity level of Ps. aeruginosa RAO 303 to the therapeutic pyocyanic phage. The systems of restriction and modification of DNA coded with plasmids were not detected. A possible changing of the phage type of Ps. aeruginosa strains under the effect of R plasmids should be considered in epidemiological assays and respective treatment measures.