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Biomedical subjects

R D Barabash

Publications and source records attributed to R D Barabash.

At least 19 recordsLinked to original sources
PubMed1991

Photodynamic therapy to treat tumors of the extrahepatic biliary ducts. A case report.

The poor survival rate of patients with extrahepatic bile duct tumors is well documented. Over the course of 4 years, we treated a white woman with diabetes diagnosed with histologically proven adenocarcinoma of the common bile duct with six injections of dihematoporphyrin ether followed by seven photodynamic therapy treatments to the biliary duct. As of July 1989, the patient was still alive, was not jaundiced, and had a Karnofsky performance status of 70. No changes occurred in any blood chemistry value from the time of injection to the time of photodynamic therapy. Of the transient elevations of some blood chemistry values and the white blood cell count, which occurred within 24 to 48 hours after photodynamic therapy, only those of alanine aminotransferase, aspartate aminotransferase, and amylase were significant.

Adenocarcinoma↗
PubMed1991

[The dynamics of intravascular thrombocyte aggregation in photodynamic exposure].

The alterations taking place in the microvessels of the rat mesentery and liver under a photodynamic effect, were studied. Excitation of a photosensitizer injected preliminarily in the organism led to aggregation of thrombocytes in the lumen of hepatic and mesenteric microvessels until a complete obturation of the lumen. The dependence of the thrombocyte aggregate size on the duration of the photodynamic effect had a linear character whereas the photodynamic effect depended on the dosage of the photosensitizer. The level of fluorescence from the surface of the liver was found to decrease from the beginning of the photodynamic effect and become stable in hemostasis.

Animals↗
PubMed1990

Nd:YAG laser and photodynamic therapy for esophageal and endobronchial tumors under general and local anesthesia. Effects on arterial blood gas levels.

STUDY OBJECTIVE: Our objective was to determine the respiratory and acid-base metabolism response to endoscopic laser surgery for obstructive tumors, as related to the duration and different types of endoscopy, anesthesia, and laser treatment. DESIGN: The design was a case-control, cohort analytic, nonrandomized controlled survey of case series before and after endoscopic procedures. SETTING: A referral-based surgery and oncology practice at one hospital's laser center. PATIENTS: We studied a sequential sample of 82 patients in the age range from 35 to 92 years, with malignant and benign, primary and metastatic, partially and completely obstructing esophageal (15 patients) and endobronchial (67 patients) tumors. INTERVENTIONS: A total of 229 diagnostic, laser treatment, and follow-up endoscopic procedures was performed under general or local anesthesia (46 esophagoscopies and 183 bronchoscopies). The latter group consisted of 29 cases of general and 154 cases of local topical anesthesia. The last group involved 37 diagnostic and toilet bronchoscopies, 86 cases of YAG-laser tumor ablation, and 31 cases of PDT. MEASUREMENTS AND MAIN RESULTS: Direct-reading electrode measurements of arterial blood, sampled before and immediately after the endoscopic procedure, revealed statistically significant (p less than 0.001) increases in PaCO2 (200 of 229 cases) and decreases in pH (195 of 229 cases) and PaO2 (215 of 229 cases). These findings were similar after bronchoscopy and esophagoscopy, general and local anesthesia (only the decrease in pH was less pronounced in the latter case), and explorative endoscopies and different laser treatments and did not correlate with the total duration of the procedure within the wide time range of 7 to 210 minutes. The initial preoperative level of PaCO2 was considerably higher and the level of PaO2 was significantly lower in patients with endobronchial tumors, as compared to patients with esophageal cancer. A strong, inverse linear relationship was found between the perioperative changes in PaO2 and its initial level and between PaCO2 and pH changes. CONCLUSIONS: The PDT for esophageal and endobronchial malignancies is no more harmful for acid-base metabolism and respiratory functions than YAG-laser tumor ablation or any other common, nonlaser endoscopic procedure.

Adult↗
PubMed1989

[Pathogenesis of porphyrin-sensitized lethal and sub-lethal photo-injury].

By means of morphological methods the mechanisms of thanatogenesis were studied in 57 white mice after the hematoporphyrin derivative administration and xenon lamp radiation imitating the sun spectrum. In dependence of integrative doses of sensitized photoradiation and individual resistance of the organism there was observed immediate (hours), retained (days) and remote (weeks) death of animals. In the first two groups death came as a result of photocoagulation of plasma proteins and toxemic shock with liver, lung and brain injury, and in the third group--as a result of suppurative resorptive intoxication against the background of ulcerous skin necrosis.

Animals↗
PubMed1976

[Influence of salivary kallikreins on microvessels of the hamster cheek pouch and rat mesentery].

By means of in vivo microscopy the influence of human, rat, and hamster purified salivary kallikreins upon the microvessels was studied in rat mesentery and hamster cheek pouch. Dilatation of arterioles, a decrease of the venule diameter, and an increase in the number of active capillaries was revealed. The species and organ peculiarities of these effects were described. The mesentery and the cheek pouch homogenates, albumin proteins, histamine and some amino acids were capable of activating the salivary kallikreins.

Animals↗
PubMedDate not supplied

[Role of salivary kallikrein in the pathogenesis of periodontosis].

In patients with parodontosis the distinct increase in salivary kallikrein secretion was found. In Wistar rats the intensity of age atrophy of alveoli dentalis correlated with BAEE-esterase activity of mixed saliva. Desalivation considerably decreased the rate of age atrophy of parodontosis in rats. Salivary kallikrein, penetrating in active form into parodontal tissues, caused the pronounced vasodilation in dogs and golden hamsters. By means of kallikrein preparations an intensive inflammatory-dystrophical process was reproduced in parodontal tissues of Wistar rats. The local treatment of patients with parodontosis by kallikrein inhibitors was found to be especially effective.

Acetone↗
PubMedDate not supplied

[Role of salivary ribonuclease in pathogenesis of periodontosis].

In patients with periodontal disease a distinct increase in secretion of salivary acidic and alkaline RNAases was found. The RNAases activity in mixed saliva correlated with the intensity of degradation of periodontal tissues during loss of alveolar layer in aged Wistar rats and the spontaneous periodontal disease in cats. In experiments with golden hamsters salivary RNAase was found to penetrate through mucosa in active form. The purified salivary RNAase inhibited the protein biosynthesis in rabbit gingiva. Intensive atrophic alterations were produced in periodontal tissues of Wistar rats by means of purified salivary RNAase.

Alveolar Process↗
PubMedDate not supplied

[Biochemical properties of aging of rat periodontium].

The content of proteins and nucleic acids and activity of acid and alkaline proteases, RNases, phosphatases and alpha-amylase were studied in the gum and alveolar bone or rats at the age of 1, 3, 6, 12, 18 and 24 months. It is found that a degree of periodontal atrophy strongly and directly correlates with the age of rats. The concentration of DNA and RNA in alveolar bone and of RNA in gum decreases with the age. The hydroxyproline content of periodontal tissues continuously increases till the age of 18th month and then considerably decreases. The activity of trypsin-like proteases, cathepsins and alkaline RNase in periodontal tissues increases reaching the maximum at the age of 6-18 months, and the activity of alkaline phosphatase decreases in the process of aging.

Acid Phosphatase↗
PubMedDate not supplied

[Enzymatic mechanisms for antimicrobial protection of the oral cavity].

Data on the role of oral lysozyme, ribonuclease, deoxyribonuclease and peroxidase in antimicrobial defense of the macroorganism are reviewed. The biochemical and physiological properties of the enzymes secreted by salivary glands and released from emigrating leukocytes are discussed. Spectra of antimicrobial action of the enzymes and participation of these enzymes in maintaining the stability of oral biocenosis are described as well as the regulation of these enzymatic activities and the pathogenetic significance of impairments in their secretion. The most perspective aspects of the problems discussed are outlined for further investigation.

Animals↗
PubMedDate not supplied

[The pharmacokinetics of hematoporphyrin, its derivative and fluorescein during the development of carcinosarcoma].

The pharmacokinetics of fluorescein, hematoporphyrin and a derivative of hematoporphyrin was studied microspectrofluorometrically on rats with transplanted carcinosarcoma. It was shown that in the rats in contrast to intact animals the tissue concentration of fluorescein exhibits a general tendency towards an increase, that of hematoporphyrin towards a decrease and that of hematoporphyrin derivative towards an increase in all parenchymatous organs and a decrease in the skin and mucosae of the hollow organs. At the equally short period of the maximal accumulation of luminophores, the tumour tissue differs from the normal one by a pronounced delay of excretion only of hematoporphyrin derivative.

Animals↗
PubMedDate not supplied

[The pharmacokinetics of fluorescein, hematoporphyrin and its derivative during the development of granuloma].

In experiments on rats with granuloma reproduced by subcutaneous implantation of foreign material there was shown a slowing of excretion from the organism as well as a considerable redistribution between the organs of fluorescein, hematoporphyrin and its derivative as compared with intact animals. The noted changes practically did not depend on the time of granuloma development.

Animals↗