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Biomedical subjects

A Munteanu

Publications and source records attributed to A Munteanu.

17 recordsLinked to original sources
PubMed1999

Wavelet-based lossless compression of coronary angiographic images.

The final diagnosis in coronary angiography has to be performed on a large set of original images. Therefore, lossless compression schemes play a key role in medical database management and telediagnosis applications. This paper proposes a wavelet-based compression scheme that is able to operate in the lossless mode. The quantization module implements a new way of coding of the wavelet coefficients that is more effective than the classical zerotree coding. The experimental results obtained on a set of 20 angiograms show that the algorithm outperforms the embedded zerotree coder, combined with the integer wavelet transform, by 0.38 bpp, the set partitioning coder by 0.21 bpp, and the lossless JPEG coder by 0.71 bpp. The scheme is a good candidate for radiological applications such as teleradiology and picture archiving and communications systems (PACS's).

Algorithms↗
PubMed1999

Wavelet image compression--the quadtree coding approach.

Perfect reconstruction, quality scalability, and region-of-interest coding are basic features needed for the image compression schemes used in telemedicine applications. This paper proposes a new wavelet-based embedded compression technique that efficiently exploits the intraband dependencies and uses a quadtree-based approach to encode the significance maps. The algorithm produces a losslessly compressed embedded data stream, supports quality scalability, and permits region-of-interest coding. Moreover, experimental results obtained on various images show that the proposed algorithm provides competitive lossless/lossy compression results. The proposed technique is well suited for telemedicine applications that require fast interactive handling of large image sets, over networks with limited and/or variable bandwidth.

Algorithms↗
PubMedDate not supplied

Blood coagulation and fibrinolysis in hyperthermic rats.

Exposure of rats to an environment of +40 degrees C that increases central (rectal) temperature to about 40 degrees C, importantly decrease the number of thrombocytes, the blood coagulation (the Quick time and Howel time) and euglobulin lysis time (ELT). In order to search for the mechanism responsible for coagulability and fibrinolysis we studied the relations of these changes with the sympatheticoadrenergic system and with the adrenal hormonal secretion. Some parameters were thus explored after adrenalectomy and under the influence of a beta-blocking agent, Eraldin. Adrenalectomy moderately reduced these decreasing effects, excepting the ELT. Eraldin has a contrary effect. Adrenalectomy acts by suppressing the corticoid reaction and by diminishing the catecholamineones. Since Eraldin influences coagulation and fibrinolysis in an opposite sense than adrenalectomy, it may be concluded that catecholamines do moderate the effect of heating, inhibiting and not stimulating circulation, as assumed. On the contrary, corticoids (gluco- or mineralo-) contribute to the effect, influencing coagulation in hyperthermia. Both influences are slight, not determinant. Supplementary explorations revealed that repeated daily exposure for 1-2 or 3 weeks, simply in the cages in which hyperthermia was subsequently produced, decreased also the number of thrombocites, the QT and the ELT, especially the last one. The HT was less influenced. It results that these exposures, produced effects similar with hyperthermia. Heating rats after these daily repeated exposures does not influence these already changed parameters.

Adrenal Glands↗
PubMedDate not supplied

Blood coagulation and fibrinolysis in rats after hypokinesia and hyperthermia.

Coagulation and fibrinolysis were studied in rats exposed to hypokinesia (HK) obtained by including rats (for 1, 2 and 3 weeks) in small cages designed to limit their movements, permitting only spontaneous feeding (a method widely used for mimicking space flight conditions). The number of thrombocytes, the Quick time, the Howell time and the euglobulinlysis time (ELT) decreased after 1 and 2 weeks of HK; however, after 3 weeks, the parameters of coagulation approached normal control levels, while ELT was still significantly under the control values. An increased blood level of corticosterone in animals subjected to HK suggested that changes observed in the blood coagulation could be linked with it. After exposing rats to heat, similar changes were noticed, i.e. thrombocytopenia and an increase in the speed of coagulation and fibrinolysis. When hyperthermia was induced in hypokinetic animals (after 1 and 2 weeks of HK), the association of exposure to HLK and heat was not followed by a cumulative response.

Animals↗
PubMedDate not supplied

Changes in some digestive enzymes after a seven-day orbital flight.

Changes in some digestive enzymes (amylase, lipase, uropepsinogen) were studied in the serum and urine of one of the participants in the Soviet-Romanian seven-day space flight on the Soyuz 40-Saliut 6 complex. On the first day after landing it was found an increased total serum and urinary amylase, resulting from the separate increase of pancreatic and salivary amylase, determined by Skude and Ihse's method [14]. In both serum and urine, pancreatic amylase was found in higher amounts than the salivary one. Lipase was also increased. These modifications are in general in keeping with those recorded after different flights of similar duration and are part of the anabolic response. The pancreatic and salivary amylase were first investigated separately. Under the same conditions uropepsinogen was decreased, an unexpected result. Serum gastrin was increased, in agreement with a generally increased digestive activity.

Adult↗
PubMedDate not supplied

Retrospective data on the pituitary gland response during immune and neoplastic processes.

A synthesis of many experimental works performed during the last ten years regarding the nonspecific response of the pituitary gland during some immune and neoplastic processes is presented. Different modalities of the response of pituitary gland cell that vary depending on the antigen type were observed. The TAB vaccine inducing a humoral immune response determined an increased secretory activity of STH and FSH cells which are involved by their secretions in the activation of protein synthesis also including antibodies. The tumoral antigens also representing a stressing factor brought about a more intense activity besides the FSH cells, the ACTH and TSH cells.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

The influence of magnetic fields on some humoral parameters and on resistance to hyperthermia in rats.

The influence of magnetic fields of moderate intensities (50 and 120 Oe) was studied in rats after single or repeated exposures with or without a rise in environmental temperature. The following parameters were investigated: the number of erythrocytes and leucocytes, the percentage of different varieties of leucocytes, serum Na+ and K+, plasma corticosterone, ascorbic acid in adrenals, blood catecholamines, plasma fibrinolytic activity, plasma antidiuretic hormone. The resistance to hyperthermia was tested after single exposures to magnetic fields and the survival time was measured. The only significant change recorded in the number of blood cells was a leucopenia after single exposures to 50 Oe for 4 hrs. The parameters indicating the activity of the adrenal cortex were not altered significantly. A moderate rise in blood noradrenaline suggested a possible mild stimulation of the adrenergic system. The plasma fibrinolytic activity was significantly stimulated after single exposures, but no change in fibrinolysis could be recorded after repeated exposures to magnetic fields. Changes observed in plasma ADH were not conclusive. The resistance of animals to hyperthermia - as a general test of reactivity - showed minimal changes in the survival time, loss of weight, and rectal temperature in animals exposed to hyperthermia (40 degrees C) under the influence of the magnetic fields.

Animals↗
PubMedDate not supplied

The impact of laparoendoscopic surgery on the training of surgical residents.

Laparoscopic cholecystectomy is an accepted part of the training of surgical residents at present. Further procedures performed by residents include laparoscopic appendectomy, herniorrhaphy and others. This report analyzes the first 22 months of operative laparoscopy in Bakes Surgical Hospital and the impact on the training of residents. From September 1993 through May 1995 four residents performed 179 laparoscopic operations. Their operative experience has been shifted especially towards laparoscopic cholecystectomy but education in open cholecystectomy and open biliary tract procedures has not been jeopardized. It may be concluded that surgical residents can master essential laparoscopic operations without additional complications in a manner standard for training of other procedures.

Acute Disease↗