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Biomedical subjects

M Matović

Publications and source records attributed to M Matović.

7 recordsLinked to original sources
PubMed1999

The effects of excitatory amino acids on isolated gut segments of the rat.

Glutamate and aspartate are excitatory neurotransmitters in both central and peripheral nervous systems, acting on ionotropic and metabotropic receptors. In our study we have examined the effects of glutamate, aspartate, N-methyl-d-aspartate (NMDA), kainic acid and (+/-)-1-aminocyclopentane-cis-1,3-dicarboxylic acid (ACPD) on tone and spontaneous activity of isolated rat gastric fundus, jejunum, ileum, ascending colon and rectum. Both glutamate and aspartate produced concentration-dependent tonic contractions of rat fundus and rectum; the other gut segments used in the study were not responsive. While only NMDA and kainic acid produced concentration-dependent tonic contractions of isolated rat gastric fundus, all three type-selective agonists of glutamate receptors (NMDA, kainic acid and ACPD) produced tonic contractions of isolated rat rectum. The results of our study suggest that glutamate and aspartate in rat gastric fundus activate excitatory intrinsic neurons through only ionotropic receptors (NMDA and non-NMDA receptors), while the same action in rat rectum is mediated through both ionotropic and metabotropic receptors.

Animals↗
PubMed1993

[Quantitative analysis of gallbladder function using quantitative dynamic radionuclide cholecystography].

The aim of the study is to demonstrate general function of the cholecyst through selected quantitative parameters derived from the quantitative radionuclide cholecystography method, using our own computer software HIDATA, and to evaluate values of specific quantitative parameters in 15 patients presenting with chronic calculous and 15 with chronic acalculous cholecystitis. A control group comprised 10 subjects with no changes on the cholecyst. Of four quantitative parameters calculated during cholecyst filling, the only significant one was the ascending segment slope of the curve from specific ROI, that is, K1 derived from it, because it shows its functional status, depending on the changes in its wall and the lumen content. The most significant parameters which maintain motor function of the cholecyst are ejection fraction (EF) and ejection rate (ER) which are always decreased in chronic cholecystitis, regardless of the presence of calculosis and the number of calculi in the lumen. The ejection fraction is especially decreased in the multiple sclerosis group; it is significantly decreased when compared with acalculous chronic cholecystitis. Our results indicate that a selection of parameters used in clinical practice for the assessment of the cholecyst function is necessary. Our program HIDATA included a large number of parameters of which three were classified as important for the assessment of the cholecyst function (K1, EF, ER), reflecting the process of filling and emptying of the cholecyst and offering reliable and valuable data for the treatment.

Cholecystitis↗
PubMed1986

Incidence and growth of methylcholanthrene-induced tumors in mice with altered immunological status.

BALB/c mice were treated s.c. with 3-methylcholanthrene (MCA), and tumor incidence and growth were followed for 9 months. Immunological status of mice was altered by various treatments. Thymectomized, lethally irradiated, bone marrow reconstituted mice served as T-cell deficient recipients. In order to suppress natural killer (NK)-cell/macrophage functions some mice were injected with silica particles; to enhance these functions some mice were given Corynebacterium parvum (CP). Silica and CP were given simultaneously with MCA to test their influence on the presumed function of surveillance of tumor incidence, and also 2 months after MCA to test their influence on the growth of greater numbers of transformed host cells. Almost all mice developed tumors at the inoculation site and at the end of the observation period there was no difference in tumor incidence among 9 experimental groups. However, in T-cell deficient mice we observed shorter tumor duration and earlier death than in normal mice. Silica particles appeared to enhance tumor growth but the differences compared to normal controls were not significant. A single injection of CP simultaneously with MCA caused earlier tumor appearance but also slowed its growth. In contrast, CP given 2 months after MCA significantly delayed the appearance of the tumors. In regard to the tumor growth immunosuppression had stronger effects in males than in females; the opposite was true for immunostimulation treatments. We concluded that immunological status does not influence long-term tumor incidence, but that both T-cell and NK-cell/macrophage compartments strongly influence the parameters of growth of chemically induced tumors, i.e., the immune and natural resistance mechanisms do not influence the frequency of de novo arising tumors but both can slow down tumor growth.

Animals↗
PubMedDate not supplied

Sensitization of rat gastrointestinal tract to acetylcholine and histamine produced by X-radiation.

Abdominal x-radiation produces both acute and chronic disturbances of gastrointestinal motility. Anaesthetized Albino-Oxford rats received one-session x-radiation (absorbed dose 10 Gy) of whole abdomen. Two hours after irradiation the rats were sacrificed and segments of their gastrointestinal tract (gastric fundus, jejunum, ileum and ascending colon, were mounted in isolated organ bath. Acetylcholine and 5-hydroxytryptamine produced tonic contractions of all gut segments, while histamine did so only with gastric fundus. While contractile effect of 5-hydroxytryptamine was not affected by x-radiation, the responses of all gut segments on acetylcholine were potentiated and shifted towards lower concentrations. After x-radiation histamine produced concentration-dependent tonic contraction of previously unresponsive jejunum and ascending colon. The results of our study suggest that x-radiation produces acute sensitization of rat gastrointestinal tract to acetylcholine and histamine.

Acetylcholine↗
PubMedDate not supplied

[Long-term oral administration of etoposide in the treatment of patients with advanced non-small-cell carcinoma of the lung. The second phase of a clinical study].

Over the period from May 1989 to May 1992 thirty-four patients with advanced non-small cell lung cancer (NSCLC) were treated with prolonged administration of oral etoposide. Etoposide was administered in a dose of 50 mg/m2 a day for 21 days. Nine (26%) patients partially responded to the treatment that lasted 2-7 months (median 5 months). Median survival time was 6 months, and 1-year survival was 32%. The most common toxic events were alopecia and myelosuppression. No patient died of treatment-related toxicity. Results of this study demonstrate moderate efficiency of the prolonged administration of oral etoposide to patients with advanced NSCLC.

Administration, Oral↗