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1.
Urologiia ; (6): 130-135, 2021 12.
Article in Russian | MEDLINE | ID: mdl-34967175

ABSTRACT

COVID-19 is a new highly contagious infectious disease caused by the SARS-CoV-2. The World Health Organization (WHO) on March 11, 2020, has declared the novel coronavirus (COVID-19) outbreak a global pandemic. More attention is currently paid to the fact that men are more at risk for worse outcomes. In addition, SARS-CoV-2 can infect the testes, potentially affecting testosterone production, as well as having a negative influence on the reproductive potential. Our aim was to review the current concepts of the possible influence of testosterone levels on the pathogenesis of COVID-19 in men and to present the available data on the impact of COVID-19 on the structure and function of the testis. Based on the analysis of 72 articles using the MEDLINE database (PubMed), it can be concluded that testosterone is involved in the co-regulation of the synthesis of angiotensin-converting enzyme-2 and transmembrane serine protease-2, facilitating the penetration of SARS-CoV-2 into target cells and promoting easier infection in men. On the other hand, low testosterone levels increase the risk of cardiopulmonary complications. Hypogonadism appears to be an important unfavorable prognostic factor for the disease. Orchitis is a reported complication of COVID-19. Damage to testicular tissue is possible due to direct invasion by a virus, a secondary autoimmune reaction, hyperthermia and thrombosis of testicular microvessels. Prophylaxis of possible vertical and sexual transmission of infection is recommended. Despite the available data, further studies are required to assess the definite role of androgens in the course of infection and the influence of SARS-CoV-2 on male reproductive potential.


Subject(s)
COVID-19 , Hypogonadism , Humans , Male , Pandemics , SARS-CoV-2 , Testis
2.
Urologiia ; (4): 106-113, 2021 09.
Article in Russian | MEDLINE | ID: mdl-34486283

ABSTRACT

Patients with non-obstructive azoospermia (NOA), which accounts for up to 10-15% of all cases of male infertility, until recently could only become parents using donor sperm or through adoption. Modern technical capabilities of sperm extraction in combination with the use of assisted reproductive technologies, make it possible to effectively overcome infertility in this group of patients. A number of highly effective techniques have been proposed for spermatozoa retrieval. However, surgical intervention is associated with certain risks, and therefore, the choice of the optimal treatment method is under discussion. A total of 52 articles were analyzed using the MEDLINE database (PubMed) to form an overview of the current principles of examination and preparation of a patient with NOA for the surgical sperm retrieval. This review is dedicated to the role of diagnostic testicular biopsy. In addition, a comparative information on the efficacy and safety of percutaneous, fine-needle aspiration, open multifocal and microdissection (micro-TESE) testicular biopsies is presented. Of the currently available sperm retrieval techniques in the urologic armamentarium, micro-TESE seems to be both the most effective and the safest. Micro-TESE can be a cumbersome procedure, however, it provides successful treatment in situations previously associated with zero chance of pregnancy.


Subject(s)
Azoospermia , Sperm Retrieval , Azoospermia/therapy , Female , Humans , Male , Microdissection , Pregnancy , Retrospective Studies , Testis
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 251: 119323, 2021 Apr 15.
Article in English | MEDLINE | ID: mdl-33508682

ABSTRACT

In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10-15% D and 80-90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400-4000 cm-1 range, as a function of temperature (10-300 K). We provide assignments of the stretching and out-of-plane bending amine (NH2) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine. In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader's quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.


Subject(s)
Quantum Theory , Hydrogen Bonding , Spectroscopy, Fourier Transform Infrared , Temperature , Thermodynamics
4.
Phys Chem Chem Phys ; 22(40): 22943-22955, 2020 Oct 21.
Article in English | MEDLINE | ID: mdl-33026378

ABSTRACT

Monomers of 4-methoxyindole and 5-methoxyindole trapped in low-temperature xenon matrices (15-16 K) were characterized by IR spectroscopy, in separate experiments. Each compound was shown to adopt the most stable 1H-tautomeric form. The photochemistry of the matrix-isolated compounds was then investigated by exciting the matrices with narrowband UV light with λ ≤ 305 nm. Two main photoproducts, similar for each compound, have been detected: (1) 4-methoxy- or 5-methoxy-indolyl radical, resulting from cleavage of the N-H bond; (2) 3H-tautomers (4-methoxy- or 5-methoxy-) with the released hydrogen atom reconnected at the C3 ring carbon atom. The presence of the two types of photoproducts in the UV-irradiated matrices was confirmed by comparison of their B3LYP/6-311++G(d,p) calculated IR spectra with the experimental spectra emerging upon the irradiations. The mechanism of the observed phototransformations was elucidated by Natural Bond Orbital and Natural Resonance Theory computations on the methoxy-substituted indolyl radicals resulting from the N-H bond cleavage. The highest natural atomic spin densities were predicted at the C3 and N1 positions of the indolyl ring, corresponding to a predominance of the resonance structures with the radical centres located at these two atoms. As a whole, the obtained experimental and theoretical data allowed establishing a general pattern for the photochemistry of methoxyindoles under matrix-isolation conditions.

5.
Urologiia ; (4): 111-118, 2020 Sep.
Article in Russian | MEDLINE | ID: mdl-32897024

ABSTRACT

Varicocele is the most common and treatable cause of male infertility. Therefore, surgical treatment of varicocele should be recommended for motivated patients and infertile couples who do not have other identified causes of infertility. Varicocelectomy has been proved to improve sperm parameters and improve chances of successful conception in most patients. However, surgical treatment is associated with certain risks, and therefore, the choice of the optimal treatment is under discussion. A total of 78 articles using a search in MEDLINE database (PubMed) were found and included in the review, dedicated to current concepts of functional anatomy of testicular arteries and veins. The current recommendations of professional communities regarding the selection of patients for varicocelectomy are described. The efficiency and safety of various surgical procedures for varicocele is analyzed. This review suggests high inconsistences in the literature. The available information on the indications for surgical treatment, as well as comparative data on the efficiency and safety of the inguinal, laparoscopic and microsurgical sub-inguinal approaches are presented. When urologist faces with a diagnosis of varicocele, individual approach should be applied, with a discussion of both benefits and possible complications of surgical treatment. Of the many existing techniques, microsurgical ligation of dilated veins is the most preferred.


Subject(s)
Infertility, Male/surgery , Varicocele/surgery , Humans , Male , Microsurgery , Treatment Outcome , Veins
6.
Urologiia ; (4): 96-100, 2019 Sep.
Article in Russian | MEDLINE | ID: mdl-31535813

ABSTRACT

Penile prosthesis implantation is a treatment choice in patients with erectile dysfunction (ED) accompanied by cavernous fibrosis. Methods for creation of space for penile cylinders during prosthesis implantation in patents with total cavernous fibrosis are still under discussion, considering high risk of complications and decrease in penile size. In the presented clinical case, a new surgical technique for performing a three-piece penile prosthesis implantation through subcoronal approach in patient with ED, complicated by total cavernous fibrosis, is described. This clinical case represents our first experience of excavation excision of scar tissue in cavernous bodies through an innovative subcoronoral approach. As a result of performing of excavation excision of scar tissue in cavernous bodies, capacious spaces were created which allowed to use a three-piece prosthesis with a standard cylinder diameter. It ensured good long-term functional and cosmetic results. The first experience of excavation excision of fibrotic cavernous bodies during inflatable penile prosthesis implantation through subcoronal approach suggests its potential efficacy and safety in patients with ED and total cavernous fibrosis.


Subject(s)
Erectile Dysfunction , Penile Implantation , Penile Prosthesis , Fibrosis , Humans , Male , Penis
7.
Urologiia ; (3): 124-127, 2019 Jul.
Article in Russian | MEDLINE | ID: mdl-31356025

ABSTRACT

Penile prosthesis implantation is a treatment choice in patients with erectile dysfunction (ED) and concomitant penile curvature due to Peyronie disease. Methods for correction of penile deformity during prosthesis implantation are still under discussion, considering variable efficiency and higher risk of complications. Our aim was to describe clinical case which represent our first experience of performing multiple corporal incisions through innovative subcoronoral approach without subsequent substitution of tunica albuginea. As a result of graft-free technique an effective penile straightening was achieved after three-piece prosthesis implantation with good long-term functional and cosmetic results. The first experience of graft-free technique of corporotomy during penile prosthesis implantation through subcoronal approach suggests its potential efficacy and safety in patients with a combination of ED and Peyronie disease.


Subject(s)
Erectile Dysfunction , Penile Implantation , Penile Induration , Prosthesis Implantation , Humans , Male , Penile Induration/surgery , Penis
8.
J Phys Chem A ; 123(20): 4396-4405, 2019 May 23.
Article in English | MEDLINE | ID: mdl-30951634

ABSTRACT

The conformers of 2-cyanophenol (2CP) and their interconversions were studied by infrared (IR) spectroscopy after trapping the monomers of the gaseous compound into low-temperature (15 K) argon (Ar) and nitrogen (N2) matrixes. To assist in the interpretation of the experimental results, B3LYP, MP2, and QCISD electronic structure calculations were carried out for the 2CP molecule. Two planar conformers, cis and trans (orientation of OH with respect to the cyano group), are predicted with gas-phase populations at the sublimation temperature of ∼98 and ∼2%, respectively. The most stable form (cis) was experimentally identified in both cryomatrixes, whereas the less stable one (trans) was not detected in Ar but could be observed in the N2 matrix with an abundance of ∼15%. Selective and bidirectional conversion between the two identified conformers was achieved upon irradiating the compound trapped in N2 matrix with near-infrared (NIR) laser light tuned at the wavenumbers of the 2ν(OH) transitions of the respective conformers. The conformational composition of 2CP was also found to be affected by the broad-band IR radiation emitted by the spectrometer source. This effect could be suppressed, partially or completely, by using different long-pass IR filters, with cutoff values of approximately 2200, 1590, and 1170 cm-1. The observed conformational changes are rationalized in terms of a competition between the over-the-barrier (light-induced) and through-the-barrier (hydrogen atom tunneling) effects. Very interestingly, both effects occur on the same time scale.

9.
Urologiia ; (6): 166-169, 2019 12 31.
Article in Russian | MEDLINE | ID: mdl-32003189

ABSTRACT

Implantation of three-piece penile prosthesis is a gold standard in patients with severe erectile dysfunction. Currently, three surgical approach (scrotal, suprapubic and subcoronal) are used for prosthetic implantation. A method of implantation for three-piece penile prosthesis is still under discussion. The literature dedicated to an influence of surgical approach on the results of implantation for three-piece penile prosthesis in patients with severe erectile dysfunction is reviewed. The advantages and drawbacks of each technique are mentioned.


Subject(s)
Erectile Dysfunction , Penile Implantation , Penile Prosthesis , Erectile Dysfunction/surgery , Humans , Male , Penis/surgery , Scrotum/surgery
10.
Urologiia ; (3): 127-136, 2017 Jul.
Article in Russian | MEDLINE | ID: mdl-28845951

ABSTRACT

The article provides coverage of the main features of the American Urological Association (AUA) Guideline for the diagnosis and management of male urethral stricture published in 2016. Clinical guideline on this medical condition is published for the first time and is unique in the world of urology. The authors present their comments based on the accumulated experience of diagnosis and treatment of this urological condition.


Subject(s)
Practice Guidelines as Topic , Urethral Stricture/diagnosis , Urethral Stricture/surgery , Humans , Male , United States , Urologic Surgical Procedures, Male
11.
J Phys Chem A ; 121(18): 3372-3382, 2017 May 11.
Article in English | MEDLINE | ID: mdl-28409925

ABSTRACT

The molecule of 5-methoxyindole (5MOI) may adopt two conformational states, syn and anti, with respect to the relative orientation of the NH and OCH3 groups. The structure of monomeric 5MOI was characterized spectroscopically, in mid- and near-infrared domains. The conformational composition of 5MOI could be controlled in three different ways. Thermally, two conformers of 5MOI could be trapped in xenon matrixes at 16 K. Upon annealing the xenon matrix to temperatures about 30-40 K, the higher-energy syn form converted to the ground-state anti conformer. Vibrational excitations in the near-infrared domain, at the frequency of the first NH stretching overtone, 6853 cm-1, afforded the inverse conformational transformation, and a part of the anti conformer was upconverted to the syn form. Electronic excitations in the UV domain, at 315-310 nm, resulted in a total consumption of the syn form again, in favor of anti. Upon further irradiations at 308 nm, a partial repopulation of the syn form, at the expense of anti, was observed. We propose a mechanistic explanation of the observed transformations, which is based on computations of the vibrational spectra of the two conformers and also on computations of the ground state S0 and the first excited state S1 potential energy surfaces along the coordinate for conformational isomerization. The highlights of the present work are the first experimental observation of the minor syn conformer of 5MOI, evidence of the long-range vibrational energy transfer resulting in conformational isomerization upon excitation of the NH stretching overtone, and the possibility of partial conformational control of 5MOI by using electronic excitations.

12.
J Chem Phys ; 144(12): 124306, 2016 Mar 28.
Article in English | MEDLINE | ID: mdl-27036447

ABSTRACT

Conformational changes induced thermally or upon infrared excitation of matrix-isolated 6-methoxyindole were investigated. Narrowband near-infrared excitation of the first overtone of the N-H stretching vibration of each one of the two identified conformers is found to induce a selective large-scale conversion of the pumped conformer into the other one. This easily controllable bidirectional process consists in the intramolecular reorientation of the methoxy group and allowed a full assignment of the infrared spectra of the two conformers. Matrices with different conformational compositions prepared by narrow-band irradiations were subsequently used to investigate the effects of both thermal and broadband infrared excitations on the conformational mixtures. Particular attention is given to the influence of the matrix medium (Ar vs. Xe) and conformational effects of exposition of the sample to the spectrometer light source during the measurements.

13.
Urologiia ; (5): 70-78, 2016 Nov.
Article in Russian | MEDLINE | ID: mdl-28248024

ABSTRACT

AIM: To assess the incidence and grade of concomitant stress urinary incontinence (SUI) and the quality of life before and after endoscopic correction of vesicourethral anastomotic strictures (VAS) and the impact of the number of endoscopic interventions on these indicators. MATERIALS AND METHODS: This is a retrospective study of medical records and a telephone survey of patients who underwent radical prostatectomy (RP) at our clinic from 2010 to 2015 and subsequently presented with VAS. The survey included data on the severity of SUI and quality of life using QoL questionnaire before and after endoscopic VAS correction; the factors primarily affecting the quality of life (SUI or obstructive symptoms) were identified. RESULTS: During the above period, 1453 RP were performed. There were 60 VAS cases, of which 56 (93%) were included in the study. Stress urinary incontinence after RP occurred in 64.3% of patients, the average QoL score was 3.95 ( = 0.64; Cv = 16.2%). Before endoscopic VAS correction, 87.5% of patients reported obstructive symptoms as the main cause of dissatisfaction. After endoscopic VAS correction, SUI was observed in 82.1% of patients. De novo incontinence occurred in 15 patients, higher SUI grade was observed in 29 (51.8%) patients. The observed change in the of SUI grade was not statistically significant (paired Students t-test 1.98, p> 0.05). Mean QoL score after endoscopic correction was 2.54 ( = 0.73; Cv = 28.6%, paired Students t-test 5.08, p <0.05). After endoscopic correction of VAS, 78.6% of the patients reported that SUI was the most important factor for decreased quality of life. CONCLUSIONS: The study revealed a high incidence of VAS combined with SIU. There was a significant improvement in patients quality of life after endoscopic correction of VAS, which resulted from a change in the pattern of voiding dysfunction producing a major negative impact on the quality of life. There were no statistically significant correlations between the number of endoscopic corrections of VAS and the SUI grade and the patients quality of life.


Subject(s)
Postoperative Complications/surgery , Quality of Life , Urethral Stricture/surgery , Urinary Incontinence, Stress/surgery , Anastomosis, Surgical , Humans , Male , Middle Aged , Postoperative Complications/etiology , Postoperative Complications/psychology , Prostatectomy/adverse effects , Recurrence , Reoperation , Retrospective Studies , Surveys and Questionnaires , Urethral Stricture/etiology , Urethral Stricture/psychology , Urinary Incontinence, Stress/etiology , Urinary Incontinence, Stress/psychology
14.
Bull Exp Biol Med ; 159(1): 157-63, 2015 May.
Article in English | MEDLINE | ID: mdl-26033608

ABSTRACT

We present the results of electron microscopic, microbiological, immunohistochemical, and molecular genetic studies of gastric biopsy specimens taken for diagnostic purposes according by clinical indications during examination of patients with gastrointestinal pathology. Immune homeostasis of the gastric mucosa against the background of infection with various pathogen strains of Helicobacter pylori was studied in patients of different age groups with peptic ulcer, gastritis, metaplasia, and cancer. Some peculiarities of Helicobacter pylori contamination in the gastric mucosa were demonstrated. Immune homeostasis of the gastric mucosa in different pathologies was analyzed depending on the Helicobacter pylori genotype.


Subject(s)
Antigens, Bacterial/genetics , Bacterial Proteins/genetics , Gastric Mucosa/microbiology , Helicobacter Infections/immunology , Helicobacter pylori/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/therapeutic use , Child , Child, Preschool , Female , Gastric Mucosa/immunology , Gastritis/diagnosis , Gastritis/microbiology , Genotype , Helicobacter Infections/drug therapy , Helicobacter Infections/microbiology , Helicobacter pylori/immunology , Humans , Infant , Infant, Newborn , Male , Metaplasia/diagnosis , Metaplasia/microbiology , Microscopy, Electron , Middle Aged , Peptic Ulcer/diagnosis , Peptic Ulcer/microbiology , Phosphorylation , Stomach Neoplasms/diagnosis , Stomach Neoplasms/microbiology , Young Adult
15.
Article in English | MEDLINE | ID: mdl-25589387

ABSTRACT

The conformational space of 3,4-dihydroxyphenylacetic acid (DOPAC), an important dopamine metabolite, has been investigated by quantum chemical methods (B3LYP and MP2, with the 6-311++G(d,p) basis set) and matrix-isolation infrared spectroscopy. Detailed analysis of the calculated potential energy surfaces of the molecule led to identification of thirteen unique conformers, all of them showing the acetic acid side chain out of the aromatic ring plane by 60-95°. According to the calculated Gibbs energies, the five lowest energy conformers make up 99.7% of the conformational mixture at 298.15K, exhibiting individual populations falling between 16% and 24%. The main conformational trends of this molecule were interpreted on the grounds of a thorough analysis of the structural parameters and by the application of the Natural Bond Orbital theory. The role of the intramolecular interactions on the relative stability and structure of the conformers was also investigated. The infrared spectrum of DOPAC was registered after isolation of its monomers in argon and xenon matrices. Only one of DOPAC forms populated in the gas phase could be trapped in both matrix gases. This result is in agreement with the predicted low energy barriers for conformational isomerization and is also supported by annealing experiments. The spectra of matrix-isolated model compounds, phenylacetic acid and catechol, were studied under the same experimental conditions. These data were used as references and assisted in the interpretation of the results obtained for DOPAC.


Subject(s)
3,4-Dihydroxyphenylacetic Acid/chemistry , Hydrogen Bonding , Models, Molecular , Molecular Conformation , Quantum Theory
16.
Bull Exp Biol Med ; 157(5): 628-33, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25257428

ABSTRACT

The cells in the skin tumor developing under conditions of persisting papillomavirus infection are morphologically identical to blast cells in a blood smear from a leukemia patient. The cells filling the lesion focus are morphologically and immunohistochemically related to blood stem cells. A mechanism of epithelial layer modification under conditions of papillomavirus infection leading to carcinogenesis is proposed. The dynamics of structural changes in the skin is characterized by disturbed interactions between the epithelium and adjacent connective tissue, destruction of the basal membrane, disorders in the cambial keratinocyte differentiation, and absence of the spinous and granular layers. We conclude that detection of blast leukocytes in the human skin lesion can be explained by disorders in the cell-cell interactions in the epithelium-mesenchymal tissue system. High proliferative activity followed by death of cambial keratinocytes, migration of effector antigen-presenting CD68 cells to the adjacent connective tissue are the factors inducing migration of blast leukocytic forms to the focus. Not only keratinocyte restitution capacity, but also epithelium-dependent differentiation of young leukocytes disappeared. Undifferentiated cells are migrated from the blood to the epithelium alteration zone, but not in the reverse direction. The insufficiency or the absence of blood blast cell differentiation of the in the focus of epidermal injury and adjacent tissue triggers carcinogenesis. The authors suggest their model of carcinogenesis. The conclusions offer a new concept of cancer pathogenesis and suggest a new strategy in the search for methods for early diagnosis of carcinogenesis.


Subject(s)
Alphapapillomavirus/isolation & purification , Skin Neoplasms/virology , Aged , Alphapapillomavirus/pathogenicity , Cell Transformation, Neoplastic , Cell Transformation, Viral , Humans , Middle Aged
17.
Bull Exp Biol Med ; 157(1): 56-61, 2014 May.
Article in English | MEDLINE | ID: mdl-24915947

ABSTRACT

We analyzed local reactions of immune homeostasis in the human skin, in particular, effector immune cells CD68 responsible for antigen presentation, during human papillomavirus infection. Under conditions of long-term papillomavirus infection, CD68 markers were identifi ed only in the connective tissue of the skin (derma) and were completely absent in the epidermis, where they were found during physiological and reparative regeneration after thermal injury. We concluded that hypertrophy of the epidermis and connective tissue of the dermal papillary layer in human papillomavirus infection is related to the absence of CD68 immune cells in the epithelial plate and their accumulation in the connective tissue adjacent to the basement membrane of the epidermis. The possibility of epithelium contamination with the virus depends on local immune homeostasis. Therefore, induction of proper CD68 distribution in appropriate structures can contribute to normalization of epithelial-connective tissue interactions.


Subject(s)
Antigen-Presenting Cells/pathology , Basement Membrane/pathology , Connective Tissue/pathology , Dermis/pathology , Epidermis/pathology , Papillomavirus Infections/pathology , Antigen-Presenting Cells/immunology , Antigen-Presenting Cells/virology , Antigens, CD/immunology , Antigens, CD/metabolism , Antigens, Differentiation, Myelomonocytic/immunology , Antigens, Differentiation, Myelomonocytic/metabolism , Basement Membrane/immunology , Basement Membrane/virology , Biomarkers/metabolism , Cell Differentiation , Connective Tissue/immunology , Connective Tissue/virology , Dermis/immunology , Dermis/virology , Epidermis/immunology , Epidermis/virology , Humans , Immunophenotyping , Papillomaviridae/physiology , Papillomavirus Infections/immunology , Papillomavirus Infections/virology , Tissue Culture Techniques
18.
Bull Exp Biol Med ; 156(4): 491-4, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24771435

ABSTRACT

The reactions of dermal structures to subcutaneous injections of gold nanoparticles were studied in CBA mice. Routes of the nanoparticles migration after injection and the mechanisms of their effects on the adjacent tissues were studied. Injected nanoparticles were phagocytosed by macrophages; some of them migrated to lymphoid follicles of the lymph node, while others migrated into blood vessels, where the particles were released from the macrophage cytoplasm into circulating blood. The endothelium was destroyed as a result of the toxic activity of macrophages loaded with nanoparticles. Two mechanisms of angiogenesis inhibition and death of blood vessels in tissues after injection of nanoparticles were distinguished. One mechanism consisted in deactivation of macrophages producing vascular endothelium growth factor inducing the formation of endothelium in the growing blood vessels, but not in direct inhibition of this factor. The other mechanism was realized through direct death of the endothelium in migration of macrophages through the vascular wall.


Subject(s)
Gold/toxicity , Metal Nanoparticles/toxicity , Skin/pathology , Animals , Endothelium, Vascular/drug effects , Endothelium, Vascular/pathology , Gold/pharmacokinetics , Injections, Subcutaneous , Lymph Nodes/metabolism , Macrophages/drug effects , Macrophages/physiology , Male , Mice, Inbred CBA , Phagocytosis , Skin/blood supply , Skin/metabolism , Tissue Distribution
19.
J Chem Phys ; 140(6): 064306, 2014 Feb 14.
Article in English | MEDLINE | ID: mdl-24527914

ABSTRACT

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol(-1) energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol(-1)) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol(-1)). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm(-1), where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm(-1), transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed.


Subject(s)
Acetic Acid/chemistry , Tetrazoles/chemistry , Isomerism , Models, Molecular , Molecular Conformation
20.
Bull Exp Biol Med ; 155(6): 788-92, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24288767

ABSTRACT

The effects of multiwalled carbon nanotubes on epitheliocytes of different compartments of the gastrointestinal tract and urothelium of different compartments of the renal nephron were studied in CBA mice. The nanotubes affected mouse gastrointestinal mucosa and renal urothelium. The cell reaction in the macula densa of the renal distal tubules and the immune system reaction to oral nanotubes were detected. A possible effect of nanotubes administered orally on the renal filtration function was hypothesized.


Subject(s)
Drug Carriers/toxicity , Intestinal Mucosa/drug effects , Nanotubes, Carbon/toxicity , Administration, Oral , Animals , Drug Carriers/metabolism , Gastrointestinal Tract/cytology , Gastrointestinal Tract/drug effects , Intestinal Absorption , Kidney Tubules, Distal/drug effects , Male , Mice , Mice, Inbred CBA , Urothelium/drug effects
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