[The results of the surgical treatment of otosclerosis in the elderly subjects].

The objective of the present study was to evaluate the effectiveness of the surgical treatment of otosclerosis in the subjects of advanced age. The medical histories of 19 patients aged above 65 years (20 ears) presenting with otosclerosis were available for the retrospective analysis. All of them had undergone surgical interventions (a total of 22 ones or 4.49% of the 489 operations performed between 2001 and 2012). The audiometric assessment was made at four wavelengths (0.5, 1, 2, and 4 kHz). Primary surgery (n=18) was preceded by the determination of the high air and bone conductivity thresholds (76.18 dB and 42.15 dB respectively), with the mean bone to air interval (BAI) being 33.99 dB. The surgical treatment resulted in the improvement of hearing; in 83.33% of the cases, BAI was reduced to 10 dB or below this value. It is concluded that the surgical intervention on the stirrup bone for the treatment of otosclerosis in the patients above 65 years of age is a safe and efficacious method despite marked hearing impairment in this group of patients.

[Stapedoplasty in a HIV-infected patient].

This paper reports an observation illustrating the possibility of the successful surgical treatment of otosclerosis in a HIV-infected patient presenting with acquired immunodeficiency syndrome (AIDS) and positive response in the test for hepatitis C. The authors used the results of multispiral computed tomography (MSCT) of the temporal bones as a basis for the prediction of the outcome of the surgical intervention taking into consideration specific primary manifestations of HIV infection as well as immunological and virlogical responses to anti-retroviral therapy.

[The potential of multislice computed tomography for the detection of specific anatomic and topographic features of the facial nerve canal prior to stapedoplasty].

The objective of the present study was to estimate the potential of multislice computed tomography (MSCT) for the detection of specific anatomic and topographic features in the structure of the middle ear and the oval window region prior to stapedoplasty. We analysed the results of MSCT of the temporal bones in 20 patients presenting with otosclerosis (40 observations). All these patients underwent stapedoplasty, and the intraoperative findings were compared with the MSCT data. Specificity and sensitivity of MSCT for the detection of structural abnormalities in the middle ear were estimated at 91.3% and 84.6% respectively. It is concluded that the preoperative MSCT examination of the temporal bones yields the data that allow for the more accurate planning of the succeeding surgical intervention as well as for choosing its optimal strategy and extent, proper instruments, the type and length of the implant (prosthesis), and thereby for avoiding the possible complications and improving the prognosis of the treatment.

[Our experience with the application of collagen-based preparations in reconstructive surgery of the middle ear].

This paper summarizes our experience with the application of collagen-based preparations for reconstructive surgery of the middle ear. The best morphological results (88.46%) were obtained by the closure of extensive defects with the Oblecolum membrane as a temporary supporting structure and the outer atraumatic dressing for the tympanic transplant (in 30 patients) or by the use of the compact-porous explants from the "Sanguicol" preparation as an overlay on the transplant (in 22 patients). Twenty seven patients presenting with the so-called "operated ear disease" underwent mastoidoplasty with the use of the compact-porous preparation "Stimul-oss" as a supporting structure to induce the ingrowth of the bone tissue and the subsequent substitution of the defect. This treatment ensured the reduction of the volume of the bony trepanation cavity. In addition, we have obtained preliminary encouraging results of the application of collagene preparations for the surgical intervention on the stirrup in the patients suffering otosclerosis.

[A case of congenital (juvenile) otosclerosis].

The present paper reports a case of congenital (juvenile) otosclerosis. This pathology is known to occur in 10% of the patients and cause severe hearing impairment. Precise diagnostics of the activity and extent of the otosclerotic process based on the results of functional multispiral computed tomography (MSCT) enables the practicing surgeons to identify indications for the surgical intervention, choose the adequate method and time for its performance, and make prognosis of its outcome. This inference is confirmed by the clinical observation described in this communication.

[A case of successful surgical treatment of labyrinth fistula in the sole hearing ear].

The objective of this communication is to demonstrate success of the surgical intervention on the sole hearing ear in the presence of absolute indications for such treatment, viz. the presence of cholesteatoma and labyrinth fistula (LF). The sensorineural loss of hearing is a rather common serious complication of LF surgery in the patients with cholesteatoma. The present observation concerns a 41 year-old woman with the history of an episode of suppurative otitis media experienced in the childhood. After a period of prolonged remission, she suffered systemic dizziness despite the intact tympanic membranes. The patient was examined with the use of multispiral computed tomography (MSCT) that revealed serious lesions in the middle ear (labyrinth fistula). It made possible careful planning and performing sanation surgery on the middle ear including tympano- and mastoidoplasty. This treatment produced good morphological and functional result.

[Conductive hearing loss caused by eustachian tube dysfunction according to the data of functional computed tomography].

The paper deals with computed tomography (CT) diagnosis of Eustachian tube dysfunction. A functional multislice spiral (MS) CT protocol has been first elaborated for the Eustachian tube. Twenty-three patients with unilateral conductive hearing loss and Eustachian tube dysfunction were examined. The normal functional anatomy of the Eustachian tube was evaluated on the side without evidence of pathology in 23 patients. Functional MSCT showed that the cartilaginous portion of the Eustachian tube opened partially and closed completely in 9 patients. Ten patients were found to have steady changes in the cartilaginous portion of the Eustachian tube. The developed method could confirm the cause of conductive hearing loss and optimally define a treatment policy.

[Functional multispiral computed tomography of sound-transmitting structures in the middle ear].

The objective of this work was to estimate the potential of functional multispiral computed tomography (fMSCT) for the choice and planning of the treatment strategy and the extent of surgical intervention in the patients presenting with fibroosseous diseases of the middle ear associated with the pathologically altered mobility of the auditory ossicles. Studies with the use of MSCT and fMSCT for the examination of temporal bones in 21 patients (25 observations) provided information about normal CT anatomy of the middle ear and a basis for the development of the fMSCT protocol; moreover they allowed the range of mobility of the auditory ossicles to be determined in healthy subjects and patients with middle ear disorders. It is concluded that fMSCT of temporal bones may be recommended to patients suffering otosclerosis, tympanosclerosis, and adhesive otitis media. The use of this technique improves the accuracy of diagnosis and facilitates the choice and planning of the treatment strategy and the extent of surgical intervention in the patients presenting with middle ear diseases.

[Peculiarities of sanitizing middle ear reoperations].

This paper is devoted to the problem of surgical rehabilitation of patients with the so-called <>. Twenty such patients underwent second operation following sanitization ear surgery for the treatment of recurrent (more than once a year) otorrhoea in the previous period. The operation was performed in two (sanitizing and reconstructive) steps. All the patients were allocated to 3 groups based on the results of preoperative examination and the cause of purulent discharge. Group 1 comprised patients with the <> Eustachian tube, group 2 included patients with the carious-granulation process in the mastoidal part of the cavity, group 3 was composed of patients with the both conditions. Reconstructive surgery in patients of groups 1 and 2 included tympanoplasty (n=7). Four patients of group 2 underwent mastoidoplasty with the use of osteotropic material Stimul-oss, and 9 patients were treated by simultaneous tympano- and mastoidoplasty using Stimul-oss blocks. The outcome of surgical treatment in all reoperated patients was regarded as positive taking into account the absence of purulent discharge from the treated ear and the formation of a small self-purifying cavity. Improved hearing was documented in 15 cases. These results give reason to recommend two-step (sanitizing and reconstructive) reoperation to patients with <> using a surgical procedure chosen individually depending on the cause of purulent discharge.

[Clinical features, diagnosis, and treatment of facial nerve lesions in the practical work of otorhinolaryngologyst].

Surgical treatment of persistent facial nerve lesions is currently the sole efficacious method for restoration of the voluntary locomotary function of mimetic muscles. Treatment of facial nerve neuropathy of otogenic nature requires a combined approach with surgical revision of the middle ear as its indispensable component including examination of the intrapetrous segment of the facial nerve canal. Facial nerve conductivity and controllable locomotary function of mimetic muscles are possible to restore by anastomosing this nerve with another (donor) one at the earliest possible stages of paresis development. Special importance of remedial gymnastics and its combination with medicamentous treatment in the pre- and postoperative periods is emphasized.

[Vestibular disorders in patients with otosclerosis: prevalence, diagnostic and therapeutic options].

A total of 177 patients with otosclerosis were selected for this study. Vestibular disorders were diagnosed in 40 (22.6%) of them. The patients were allocated to 2 groups comprising 11 and 18 subjects respectively. Patients of group 1 were given surgical treatment during the current hospitalization. Patients of group 2 were treated by conservative therapy following stapedoplasty performed 1 year or more earlier. The study included analysis of vestibular symptoms and evaluation of clinical effectiveness of the combined treatment in the form of therapy with betahistine dihydrochloride (betaserk) during 2 months and a course of 10-12 sessions of game exercises at a stabilographic complex. The patients of both groups enjoyed reduced severity of subjective and objective vestibular symptoms and statistically significant improvement of the equilibrium function assessed from statokinesigrams. It is concluded that combined vestibuloadaptive therapy is an effective method of preparation for stapedoplasty and correction of postoperative complications.

Acoustooptic interaction in science and applications.

Main results of acousto-optic investigations in physical acoustics of solids obtained in Ioffe Physico-Technical Institute during recent yeas are presented. Both monocrystals, and glass alloys of different compositions were used as objects of researches. The studies were fulfilled in wide ranges of optical wavelengths (0.63-10.6 mkm), temperatures (77-400 K) and frequencies (10-1800 MHz) of bulk and surface acoustic waves.

Acousto-electron interaction in InGaAsP/InP laser heterostructures.

The frequency modulation of the heterolaser radiation under the ultrasonic strain has been found out. The dynamic and static analysis of the spectral parameters change caused by the alternating strain has been fulfilled. A model is proposed for describing the experimental data, and their theoretical analysis is performed. It is demonstrated that the acousto-electron interaction is dominant under the action of surface waves in InGaAsP/InP laser heterostructures.

[Development and diagnostic value evaluation of a nutrient medium for the yield and isolation of hemoculture].

The effectiveness of the bacteriological study of the blood depends in many aspects on the quality of nutrient media. The currently approved nutrient media for the isolation and yield of hemocultures have low isolation rates and require prolonged time for the isolation of causative agents. A two-phase nutrient medium for the yield and isolation of hemoculture has been developed. This medium has been found to have advantages over the control "double medium" in sensitivity, yield effect, growth rate and isolation rate with respect to the causative agents of bacteriemia and sepsis. The medium is standard and ready for use. The above-mentioned advantages of the medium increase the quality of the bacteriological diagnosis of bacteriemia and sepsis.

[Selective nutrient medium for the isolation of Bacillus cereus]. / Selektivnaia pitatel'naia sreda dlia vydeleniia Bacillus cereus.

A selective dried medium for the isolation of B. cereus from clinical material and foodstuffs has been developed. The medium has high selective properties which ensure the isolation of B. cereus from microbial association in pure culture, thus making it possible to accelerate further identification of the microorganisms.

Effect of interactions between amino acid residues 43 and 61 on thermal stability of bacterial formate dehydrogenases.

NAD+-dependent formate dehydrogenases (EC 1.2.1.2, FDH) of methylotrophic bacteria Pseudomonas sp. 101 (PseFDH) and Mycobacterium vaccae N10 (MycFDH) exhibit high homology. They differ in two amino acid residues only among a total of 400, i.e., Ile35 and Glu61 in MycFDH substitute for Thr35 and Lys61 as in PseFDH. However, the rate constant for MycFDH thermal inactivation in the temperature range of 54-65 degrees C is 4-6-times higher than the corresponding rate constant for the enzyme from Pseudomonas sp. 101. To clarify the role of these residues in FDH stability the dependence of the apparent rate constant for enzyme inactivation on phosphate concentration was studied. Kinetic and thermodynamic parameters for thermal inactivation were obtained for both recombinant wild-type and mutant forms, i.e., MycFDH Glu61Gln, Glu61Pro, Glu61Lys and PseFDH Lys61Arg. It has been shown that the lower stability of MycFDH compared to that of PseFDH is caused mainly by electrostatic repulsion between Asp43 and Glu61 residues. Replacement of Lys61 with an Arg residue in the PseFDH molecule does not result in an increase in stability.

Cold-adapted alanine dehydrogenases from two antarctic bacterial strains: gene cloning, protein characterization, and comparison with mesophilic and thermophilic counterparts.

The genes encoding NAD(+)-dependent alanine dehydrogenases (AlaDHs) (EC 1.4.1.1) from the Antarctic bacterial organisms Shewanella sp. strain Ac10 (SheAlaDH) and Carnobacterium sp. strain St2 (CarAlaDH) were cloned and expressed in Escherichia coli. Of all of the AlaDHs that have been sequenced, SheAlaDH exhibited the highest level of sequence similarity to the AlaDH from the gram-negative bacterium Vibrio proteolyticus (VprAlaDH). CarAlaDH was most similar to AlaDHs from mesophilic and thermophilic Bacillus strains. SheAlaDH and CarAlaDH had features typical of cold-adapted enzymes; both the optimal temperature for catalytic activity and the temperature limit for retaining thermostability were lower than the values obtained for the mesophilic counterparts. The k(cat)/K(m) value for the SheAlaDH reaction was about three times higher than the k(cat)/K(m) value for VprAlaDH, but it was much lower than the k(cat)/K(m) value for the AlaDH from Bacillus subtilis. Homology-based structural models of various AlaDHs, including the two psychotropic AlaDHs, were constructed. The thermal instability of SheAlaDH and CarAlaDH may result from relatively low numbers of salt bridges in these proteins.

Bacterial formate dehydrogenase. Increasing the enzyme thermal stability by hydrophobization of alpha-helices.

NAD+-dependent formate dehydrogenase (EC 1.2.1.2, FDH) from methylotrophic bacterium Pseudomonas sp.101 exhibits the highest stability among the similar type enzymes studied. To obtain further increase in the thermal stability of FDH we used one of general approaches based on hydrophobization of protein alpha-helices. Five serine residues in positions 131, 160, 168, 184 and 228 were selected for mutagenesis on the basis of (i) comparative studies of nine FDH amino acid sequences from different sources and (ii) with the analysis of the ternary structure of the enzyme from Pseudomonas sp.101. Residues Ser-131 and Ser-160 were replaced by Ala, Val and Leu. Residues Ser-168, Ser-184 and Ser-228 were changed into Ala. Only Ser/Ala mutations in positions 131, 160, 184 and 228 resulted in an increase of the FDH stability. Mutant S168A was 1.7 times less stable than the wild-type FDH. Double mutants S(131,160)A and S(184,228)A and the four-point mutant S(131,160,184,228)A were also prepared and studied. All FDH mutants with a positive stabilization effect had the same kinetic parameters as wild-type enzyme. Depending on the position of the replaced residue, the single point mutation Ser/Ala increased the FDH stability by 5-24%. Combination of mutations shows near additive effect of each mutation to the total FDH stabilization. Four-point mutant S(131,160,184,228)A FDH had 1.5 times higher thermal stability compared to the wild-type enzyme.

Cold-active serine alkaline protease from the psychrotrophic bacterium Shewanella strain ac10: gene cloning and enzyme purification and characterization.

The gene encoding serine alkaline protease (SapSh) of the psychrotrophic bacterium Shewanella strain Ac10 was cloned in Escherichia coli. The amino acid sequence deduced from the 2,442-bp nucleotide sequence revealed that the protein was 814 amino acids long and had an estimated molecular weight of 85,113. SapSh exhibited sequence similarities with members of the subtilisin family of proteases, and there was a high level of conservation in the regions around a putative catalytic triad consisting of Asp-30, His-65, and Ser-369. The amino acid sequence contained the following regions which were assigned on the basis of homology to previously described sequences: a signal peptide (26 residues), a propeptide (117 residues), and an extension up to the C terminus (about 250 residues). Another feature of SapSh is the fact that the space between His-65 and Ser-369 is approximately 150 residues longer than the corresponding spaces in other proteases belonging to the subtilisin family. SapSh was purified to homogeneity from the culture supernatant of E. coli recombinant cells by affinity chromatography with a bacitracin-Sepharose column. The recombinant SapSh (rSapSh) was found to have a molecular weight of about 44,000 and to be highly active in the alkaline region (optimum pH, around 9.0) when azocasein and synthetic peptides were used as substrates. rSapSh was characterized by its high levels of activity at low temperatures; it was five times more active than subtilisin Carlsberg at temperatures ranging from 5 to 15 degreesC. The activation energy for hydrolysis of azocasein by rSapSh was much lower than the activation energy for hydrolysis of azocasein by the subtilisin. However, rSapSh was far less stable than the subtilisin.

Synthesis of optically active amino acids from alpha-keto acids with Escherichia coli cells expressing heterologous genes.

We describe a simple method for enzymatic synthesis of L and D amino acids from alpha-keto acids with Escherichia coli cells which express heterologous genes. L-amino acids were produced with thermostable L-amino acid dehydrogenase and formate dehydrogenase (FDH) from alpha-keto acids and ammonium formate with only an intracellular pool of NAD+ for the regeneration of NADH. We constructed plasmids containing, in addition to the FDH gene, the genes for amino acid dehydrogenases, including i.e., leucine dehydrogenase, alanine dehydrogenase, and phenylalanine dehydrogenase. L-Leucine, L-valine, L-norvaline, L-methionine, L-phenylalanine, and L-tyrosine were synthesized with the recombinant E. coli cells with high chemical yields (> 80%) and high optical yields (up to 100% enantiomeric excess). Stereospecific conversion of various alpha-keto acids to D amino acids was also examined with recombinant E. coli cells containing a plasmid coding for the four heterologous genes of the thermostable enzymes D-amino acid aminotransferase, alanine racemase, L-alanine dehydrogenase, and FDH. Optically pure D enantiomers of glutamate and leucine were obtained.