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Biomedical subjects

M T Ercan

Publications and source records attributed to M T Ercan.

At least 73 records · Page 4Linked to original sources
PubMed1984

Measurement of blood flow to human nasal mucosa in normal and pathological conditions by the use of the 133Xe clearance technique.

The blood flow to nasal mucosa in normal subjects and in allergic rhinitis, vasomotor rhinitis and laryngectomized patients was measured using the 133Xe clearance technique. The results were statistically compared and correlated with capillary diameter. Compared to the normal group, the blood flow to nasal mucosa increased in allergic and vasomotor rhinitis patients and decreased in laryngectomized patients. There was a statistically significant difference between allergic and vasomotor groups (p less than 0.01), so the present method could be used in the differential diagnosis of rhinitis.

Adolescent↗
PubMed1984

Measurement of nasal mucociliary activity in man with 99mTc-labelled resin particles.

The mucociliary activity in normal and pathological nasal mucosa was studied with a gamma camera using 99mTc-labelled resin particles. The mucus flow rate was investigated under physiological conditions in the following groups of subjects: normal, allergic rhinitis, vasomotor rhinitis, primary atrophic rhinitis, and laryngectomized. The mean flow rates obtained were 5.7 +/- 2.2, 1.5 +/- 0.5, 1.9 +/- 0.8, 0.0, and 4.8 +/- 1.9 mm/min respectively. When the results were compared, the differences between the normal and allergic rhinitis groups, and the normal and vasomotor rhinitis groups were statistically significant (p less than 0.05). However, the differences between the normal and laryngectomized groups, and the allergic and vasomotor rhinitis groups were insignificant (p greater than 0.05).

Adolescent↗
PubMed1982

Liver blood flow rate and glucose metabolism in hemorrhagic hypotension and shock.

Liver blood flow was measured in dogs using 133Xe clearance technique under control conditions and during various stages of hypotension and of hemorrhagic shock. Initial liver mean blood flow rate in all dogs combined are 101.9 +/- 11.5 ml/100 gm liver/min and was not significantly altered in the control group. Liver blood flow rate was reduced in the experimental group during hemorrhagic hypotension and shock and was correlated with the severity of the disease. Peripheral vasodilatation was observed in one subgroup of experimental animals while severe vasoconstriction was found in another subgroup. Glucose concentrations in the hepatic vein were significantly above that of arterial and portal venous blood; all experimental animals were hyperglycemic. The outflow of glucose from the liver was increased during shock in ten animals. It was, however, reduced in 17 animals.

Animals↗
PubMed1981

Net insulin secretion and IRI response to 1 mg glucose during OGTT.

Dogs in postabsorbtive state were anesthetized with IV nembutal. Their femoral arteries were catheterized, and the abdomens were entered via a midline incision. A small branch of the pancreatic artery and a corresponding small vein were catheterized. 133Xe was injected through the artery, and the the pancreatic blood flow rate (PBFR) was determined. Net insulin secretion was calculated using the insulin concentration of pancreatic vein-artery difference and pancreatic plasma flow rate (PPFR). After control studies an oral glucose tolerance test (2 g/kg body wt.) was performed. Under control studies the mean value of net insulin secretion was 3,753.2 +/- 699.1 microunits/100 g P/min and the maximum values were 10,610.2 +/- 3,658.7 and 11,108.0 +/- 2,852.6 microunits/100 g P/min at 20 and 60 min after glucose loading, respectively (P less than 0.05). Insulin response per mg of glucose was 83.2 +/- 12.2 microunits under control conditions. Twenty minutes after glucose loading this figure rose to 173.4 +/- 41.7 microunits/mg glucose and at 60 min 207.9 +/- 49.2 microunits/mg glucose.

Administration, Oral↗
PubMed1980

99mTc-methyl-CCNU for the static imaging of kidneys.

A new radiopharmaceutical, 99mTc-Methyl-CCNU, was prepared for the static imaging of kidneys and the radiochemical purity was tested by paper and thin-layer chromatography. The biological distribution was studied in 15 mice sacrificed at 10 min. 30 min, 1 h, 3 h, and 6 h after IV injection. Blood clearance and excretion of the agent in urine were followed in three volunteers for a period of 24 h. Renal uptake was high (25% in 6 h), plasma clearance very fast (90% in 1 h), and urinary excretion reached a platueau after 6 h with 25% excretion. A longitudinal slice of a rabbit kidney showed the cortical accumulation on autoradiography and scintigraphy. Clinical studies indicated the usefulness of this radiopharmaceutical as a kidney imaging agent.

Animals↗
PubMed1980

Pancreatic blood flow in hemorrhagic shock.

Pancretic blood flow rates were determined using a 133Xe washout technique in a total of 40 dogs, 14 of which were used as a control group and the remaining 26 as the experimental group. The initial pancreatic blood flow rates of control group and of the experimerntal group were 85.1 +/- 10.1 ml/100 g/min of pancreas/min and 81.1 +/- 5.4 ml/100 g/min respectively. These values were not significantly different from each other (P > 0.05). In the control group the blood flow was determined 3 times at 30 min intervals. These mean values were 73.0 +/- 9.4, 74.6 +/- 8.7, and 79.4 +/- 10.4 m/100 g/min respectively (P > 0.05). The dogs in the experimental group were bled and the peripheral arterial blood pressure was reduced stepwise to 80, 50, and 30 mm Hg. At each level at 30 min of stabilization period the pancreatic blood flow rates were 49.8 +/- 3.7, 29.3 +/- 2.3 and 20.2 +/- 2.3 ml/100 g/min respectively. These mean values were very significantly reduced compared to those of the control group at 30 min (P < 0.02), at 60 and 90 min (P > 0.001). They were also very significantly different from their own initial values (P < 0.001). The metabolic consequences of this reduction in pancreatic blood flow are discussed.

Animals↗
PubMed1978

The effects of cortisone on liver blood flow in experimental hemorrhagic shock: using a new simplified radioisotope clearance method to measure liver blood flow.

Liver blood flow was measured in the dog under control and hemorrhagic shock conditions by the 133Xe clearance method. 133Xe was administered first into the portal vein and its clearance from the liver recorded, and then directly into the liver tissue and another clearance curve was obtained. The resuts were compared. We have also investigated the effects of corticosteroids, given in pharmacologic doses, on liver blood flow in hemorrhagic shock. We have shown that the difference between the results of tissue injection and those of portal injection of 133Xe was not significant (p greater than 1.10). Hemodynamic studies indicated that the liver blood flow is decreased, the liver venous resistance and portal venous pressures are increased in dogs in hemorrhagic shock, and that hydrocortisone, with the blood pressure and the bleedout volume held constant in the experimental model, lowers the liver venous resistance and raises the liver blood flow significantly (p less than 0.05) at various stages of hemorrhagic shock.

Animals↗
PubMedDate not supplied

Scintigraphic evaluation of tumors metastatic to the choroid using technetium-99m(V)-dimercaptosuccinic acid.

Technetium-99m(V)-dimercaptosuccinic acid scintigraphy was used to evaluate three patients with intraocular tumors who had metastatic breast, lung, and rectal carcinomas, respectively. At the time of initial examination, two patients had no known systemic cancer, but the scintigraphy results in one patient revealed the primary site and were highly suggestive of disseminated carcinomatosis in the other patient. In the third patient, scintigraphy was successful to confirm very small bilateral intraocular tumors and also other systemic lesions. Technetium-99m(V)-dimercaptosuccinic acid scintigraphy can be reliably employed in a very select group of patients with intraocular tumors where metastatic carcinoma is a serious diagnostic possibility against a primary intraocular malignancy. This safe and promising tumor-imaging agent has the ability to demonstrate the ocular lesions and other systemic foci simultaneously, information that would prove to be crucial in both the diagnosis and the management of the patient.

Adenocarcinoma↗
PubMedDate not supplied

In vitro evaluation and intra-articular administration of biodegradable microspheres containing naproxen sodium.

The dispersion of non-steroidal antiinflammatory drugs (NSAIDs) into biodegradable polymeric matrices have been accepted as a good approach for obtaining a therapeutic effect in a predetermined period of time meanwhile minimizing the side effects of NSAIDs. In the present study, it was aimed to prepare Naproxen Sodium (NS), (a NSAID) loaded microsphere formulation using natural Bovine Serum Albumin (BSA) and synthetic biodegradable polymers such as poly(lactide-co-glycolic acid) (PLGA) (50:50 MW 34,000 and 88,000 Da) for intra-articular administration, and to study the retention of the drug at the site of injection in the knee joint. NS incorporated microspheres were evaluated in vitro for particle size (the mean particle size; for BSA microspheres, 10.0 +/- 0.3 microm, for PLGA microspheres, 9.0 +/- 0.2 and 5.0 +/- 0.1 microm for MW 34,000 and 88,000 Da, respectively), yield value, drug loading, surface morphology and drug release. For in vivo studies, monoarticular arthritis was induced in the left knee joints of rabbits by using ovalbumin and Freund's Complete Adjuvant as antigen and adjuvant. A certain time (4 days) is allowed for the formation of arthritis in the knee joints, then the NS loaded microspheres were injected directly into the articular cavity. At specific time points, gamma scintigrams were obtained to determine the residence time of the microspheres in knee joints, in order to determine the most suitable formulation. This study indicated that PLGA, a synthetic polymer, is more promising than the natural type BSA microspheres for an effective cure of mono-articular arthritis in rabbits.

Animals↗
PubMedDate not supplied

In vitro and in vivo evaluation of diclofenac sodium loaded albumin microspheres.

The use of polymeric carriers in formulations of therapeutic drug delivery systems has gained widespread application, due to their advantage of being biodegradable and biocompatible. Among the microparticulate systems, microspheres have a special importance since it is possible to target drugs and provide controlled release. Diclofenac sodium (DS), is a potent drug in the NSAID group having non-steroidal, anti-inflammatory properties, and is widely used in the treatment of rheumatoid arthritis, osteoarthritis and ankylosing spondylitis. In this present study, it was aimed to prepare microsphere formulations of DS using a natural biodegradable polymer as a carrier for intraarticular administration to extend the duration period of the dosage form in the knee joint. Microsphere formulations of DS which were prepared were evaluated in vitro for particle size, yield value, encapsulation efficiency, surface morphology, and in vitro drug release. Two appropriate formulations were selected for in vivo trials. For the in vivo studies, Technetium-99m labelled polyclonal human immunogammaglobulin (99mTc-HIG) was used as the radiopharmaceutical to demonstrate arthritic lesions by gamma scintigraphy. After the induction of arthritis in knee joints of rabbits, the radio-labelled microspheres loaded with DS were injected directly into the articular cavity and at specific time points gamma scintigrams were obtained to find the residence time of the microspheres in knee joints in order to determine the most suitable formulation.

Animals↗
PubMedDate not supplied

Scintigraphic imaging of infections with 99m-Tc-labelled glutathione liposomes.

In this study, liposomes containing glutathione were evaluated to detect infection in mice. Glutathione liposomes were labelled by using 99mTc-labelled-HMPAO (hexamethyl propylamine oxime). Mice were infected in the thigh by intramuscular injection with turbentine. Labelled liposomes were applied to the tail vein of the mice intravenously. At fixed time intervals they were sacrificed. The animals were imaged under a gamma camera. Then, tissue samples were excised and radioactivity of all organs was counted. Abscess-to-muscle, abscess-to-liver, and abscess-to-spleen ratios were calculated. The ratios of abscess-to-muscle were found to be 1.6 and 11.6 at 1 h and 24 h, respectively. According to these data, the abscess can be defined at 1 h and it became more clear with time.

Abscess↗
PubMedDate not supplied

Evaluation of 99mTc labelled poly lactic acid microspheres for diagnostic radioembolization.

Radioembolization is used in diagnostic imaging of the lungs and for radioembolization therapy of hepatic tumours. Presently, 99mTc labelled macroaggregates or microspheres of human serum albumin (HAM) are used for this purpose. Poly lactic acid (PLA) is biodegradable, like HAM, and, unlike HAM, is not a blood product. The aim of the present study was to evaluate the uptake and biodegradation of PLA microspheres in lungs. PLA (MW = 48720 Da) microspheres of 1.0-100 microm (mean = 39.5 microm) in diameter were prepared by solvent evaporation from methylene chloride. They were labelled with 99mTc by stannous chloride reduction at pH 3, with an efficiency of 98% and a stability of 96% at 24 h. For biodistribution studies, 15 mice were i.v. injected with 20 microCi 99mTc-PLA microspheres in 0.1 ml and sacrificed at 15 min, 1, 3, 6 and 24 h (three at each time point). All the organs were removed, weighed and counted against a standard prepared from 1/100 dilution of the injected radioactivity. Some mice were similarly injected and sacrificed at 30 min, 15 and 30 days. The lungs were removed and frozen, and 10 microm sections were obtained, stained with haemotoxylin and eosin and examined under a light microscope. Five rabbits were i.v. injected with 1 mCi of 99mTc-PLA microspheres. Scintigrams were obtained at various intervals up to 24 h. In mice, the lung uptake was significant at 30 min-1h post-injection. In rabbits, the lungs were the only organs visualized up to 24 h. Microscopic examination of tissue sections demonstrated slow biodegradation of PLA particles. In conclusion; (1) The high lung uptake obtained in mice and rabbits indicates the suitability of PLA microspheres for lung imaging, and (2) although the slow biodegradation rate might be a disadvantage in patients with lung disorders in diagnostic studies, it may be an advantage in therapeutic applications with radionuclides which have long physical half lives.

Animals↗