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Biomedical subjects

R Krstić

Publications and source records attributed to R Krstić.

At least 19 recordsLinked to original sources
PubMed1996

[Congenital leukemia--personal experience].

Congenital leukemia is a very rare form of acute leukemia and up to now more than 100 well documented cases have been published. Symptoms and signs of the disease may be faintly differentiated and be a differential diagnostic problem for a long period of time in comparison to other common diseases of the newborn. This is a case report on two newborns with congenital leukemia. It was an acute non-lymphoblastic leukemia in the first case, and acute lymphoblastic leukemia in the second. In both cases there were nonspecific manifestations of the disease (no weight gaining, hemorrhagic enterocolitis). In both cases polyhemotherapeutic protocols were performed. In the first case only partial remission occurred and death occurred during the hemathologic recidive of the disease. In the second case, 15 months after the diagnose of congenital leukemia has been established, complete remission is in course.

Humans↗
PubMed1996

[Infiltration of the testes in acute lymphoblastic leukemia in childhood--personal experience].

According to various literature data testicular leukemic infiltration occurs in 5-40%, while the mean time for testicular recurrence is 36 months. Hematologic recurrence usually occurs in the interval from 1-6 months. Although testicular leukemic infiltration clinically occurs as an isolated recurrence of leukemia, it usually presents only a clearly marked spot in the general recurrence of the disease. It is a painless enlargement of one or both testes. The diagnosis is made ultrasonographically and by histopathologic examination of the biopsied testicle tissue. This paper deals with 4 patients with acute lymphoblastic leukemia and testicular recurrence. In 2 patients the testicular recurrence occurred as a part of the general recurrence of the disease, while in the other 2 at the time of testicular recurrence diagnosis, the bone marrow was regular. All 4 patients were treated with combined radiotherapy and chemotherapy, in 3 cases successfully.

Child↗
PubMed1995

[Congenital methemoglobinemia].

This is a report on a case of inborn methemoglobinemia. The disease has been diagnosed in the first week of infant's life. At first it was assumed it was a case of inborn heart defect because of expressed generalized cyanosis, but very soon it was excluded. Values of methemoglobin were extremely high, so three days after birth hereditary methemoglobinemia was diagnosed. Our diagnosis was confirmed by disappearing of cyanosis after ascorbic acid was applied, by values of methemoglobin reductase of the infant and its father, anamnestic data revealing that mother had had temporary cyanosis during her infancy, and satisfactory clinical course of illness.

Diagnosis, Differential↗
PubMed1994

[Whipple's disease. Case report].

This is a case report on a 42 years old patient suffering from Whipple's disease. The patient had characteristic symptoms: high temperature, frequent bowel movement, melanoderma, arthralgia and enlarged lymph nodes. After detailed clinical researches, x-ray and endoscopic examination, bacteriology examination of faeces, absorptional tests, the diagnosis was made thanks to pathohistologic analysis of biopsy samples of the small intestine by light and electron microscopy. The differential diagnostic similarity with AIDS, especially at the early phase of the illness, required excluding HTLV III. We examined the aetiophathogenesis of the illness and discussed the clinical and laboratory presentation of the patient considering contemporary ideas regarding this disease.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Light and electron microscopic immunocytochemical localization of glutamine synthetase in the superficial pineal gland of the rat.

Glutamine synthetase (L-glutamate:ammonia ligase; EC 6.3.1.2), an enzyme catalysing the ATP-dependent formation of glutamine from glutamate and ammonia, was detected immunocytochemically only in glial (interstitial) cells of the superficial pineal gland of the rat. The results show the important role of pineal glial cells in the metabolism of the presumptive neurotransmitters, glutamate and gamma-aminobutyric acid (GABA) as well as in detoxification of ammonia.

Animals↗
PubMed1988

Comparison of calbindin D-28K immunoreactivity in superficial pineal bodies of mongolian gerbil and rat.

Immunocytochemical reaction for demonstration of calbindin D-28K has been performed in superficial pineal bodies of the Mongolian gerbil (Meriones unguiculatus) and the rat. Whereas in the Mongolian gerbil there were no clearly expressed calbindin immunoreactive cells, these were numerous in the rat pineal body. Here the calbindin-positive cells - probably pinealocytes - were disposed along capillaries. In view of the role of calbindin in binding and transporting calcium and regulating its intracellular levels, the absence of this protein in the gerbil pineal body has been interpreted as signifying the inability of pinealocytes to eliminate intracellular calcium with possible consequent formation of acervuli.

Animals↗
PubMed1988

Tubular lysosomes in rat and gerbil pinealocytes.

Ultracytochemical demonstration of acid phosphatase (AcPase) in pinealocytes of rat and Mongolian gerbil (Meriones unguiculatus) has revealed an existence of tubular lysosomes (30-200 nm in diameter and more than 5 micron long) in their cytoplasm. The tubular lysosomes arise by bulging from GERL cisternae (Golgi apparatus, endoplasmic reticulum, lysosomes) and spread throughout the whole cell body without forming an anastomosing network. Numerous varicosities are characteristic for the tubular lysosomes whose similarity with grumose bodies has lead to conclusion that the vermiculate variety of the latter are almost certainly tubular lysosomes. The role of these organelles is unknown. Their possible engagement in a rapid cytoplasmic remodelling of the pinealocyte body in answer to various stimuli has been discussed.

Acid Phosphatase↗
PubMed1986

Ultracytochemical evidence for the presence of GERL in pinealocytes of the Mongolian gerbil (Meriones unguiculatus).

Ultracytochemical reactions for the demonstration of acid phosphatase, glucose-6-phosphatase and thiamine pyrophosphatase, as well as zinc iodide-osmium tetroxide impregnation, revealed the existence of GERL (Golgi apparatus-Endoplasmic Reticulum-Lysosomes) in pinealocytes of the Mongolian gerbil (Meriones unguiculatus). The spatial arrangement of this structure was studied on thick sections using a goniometric stage. Although it was not possible to determine whether GERL in pinealocytes belongs to the Golgi apparatus or to endoplasmic reticulum, it can be concluded that its presence in studied cells signifies that they are considerably more active synthetically than has been believed to date.

Acid Phosphatase↗
PubMed1986

Pineal calcification: its mechanism and significance.

On the basis of conventional transmission electron microscopy and ultracytochemical reactions for demonstration of calcium, for glucose-6-phosphatase, and for Ca2+-ATPase, intracellular and extracellular mineralization foci in the superficial pineal gland of the Mongolian gerbil (Meriones unguiculatus) have been described. The initial intracellular calcification sites occur in the cytoplasmic matrix, vacuoles, mitochondria and the endoplasmic reticulum of large clear pinealocytes. These loci, and particularly those within the cytoplasmic matrix, transform into acervuli by a further addition of hydroxyapatite crystals. The cells gradually degenerate, die, break down, and the acervuli reach the extracellular space. It has been suggested that the reason for a rise in intracellular calcium levels could be the incapacity of Ca2+-ATPase to eliminate this cation from the cell, so that the hypercalcemic intracellular milieu becomes favourable for the initial crystallization. The primary extracellular mineralization sites occur in the calcium-rich flocculent material. The mineralization process in the gerbil pineal gland is interpreted as a histophysiological phenomenon intimately related to the metabolic activity of the pineal gland.

Animals↗
PubMed1985

Formation of autophagosomes in the pinealocytes of the rat and mongolian gerbil (Meriones unguiculatus): a lysosome wrapping mechanism?

Autophagosome formation in rat and gerbil pinealocytes is described. It starts with the setting up of a tubular acid phosphatase-rich cisterna which gradually wraps around cytoplasmic areas to be catabolized. In light of obtained findings, it seems that the autophagosome formation in pinealocytes is a type of lysosome wrapping mechanism.

Acid Phosphatase↗
PubMed1985

Ultracytochemical localization of calcium in the superficial pineal gland of the Mongolian gerbil.

In order to demonstrate fine localization of Ca2+ in the superficial pineal gland of Meriones unguiculatus, the pyroantimonate technique was employed. Control experiments were performed with EGTA and analysis of obtained reaction product using an energy-dispersive x-ray microanalysis. Precipitates of calcium antimonate were formed almost exclusively in swollen clear pinealocytes, in and along their cell membranes, over their nuclei, in mitochondria, the Golgi apparatus, endoplasmic and integrade reticulums, acervuli, in vesicles surrounding synaptic bars, cytoplasmic matrix, and flocculent extracellular material. It has been concluded that the swollen pinealocytes represent a degenerative cell form probably occurring by impairment of plasmalemmal Ca2+-ATPase's ability to eliminate Ca2+ ion from the cell, with consecutive increase of calcium in the cytoplasmic matrix, followed by increase of intramitochondrial Ca2+ concentration, gradual arrest of mitochondrial function, depolymerization of cytoskeletal microtubuli, loss of the cell form, and cell death. Decrease of function of pinealocyte plasmalemma seems to be related to aging.

Animals↗
PubMed1981

Scanning electron microscopy of the juxtaglomerular apparatus in the freeze-fractured rat kidney.

The morphology of the juxtaglomerular apparatus of the rat kidney was investigated by scanning electron microscopy of the freeze-fractured tissue. The macula densa cells have a dome-shaped apical surface abundantly provided with short microvilli. Their basal and lateral aspects may show labyrinthine spaces which are consistently more developed than in the epithelium across the tubular lumen. The Goormaghtigh cells display the well known complex pattern of cytoplasmic extensions forming the lacis. Fractured juxtaglomerular cells show distinct nuclei and well defined secretory granules. The well developed labyrinth of the macula densa suggest a considerable trans-epithelial fluid transfer at this level.

Animals↗
PubMed1980

Secretory phenomenon of the adenohypophyseal cells viewed with the scanning electron microscope.

Exocytosis from rat adenohypophyseal cells, probably somatotrophic, was studied in the scanning electron microscope after freeze fracturation of the glands. This technique permitted the distinguishing of a clearly delimited exoplasm interrupted by the passage of the secretory granules. It was postulated that the exoplasm could be involved in the control of the release of secretory granules in the endocrine cells studied. At the basal cell surface a simultaneous discharge of several secretory granules has been detected.

Animals↗
PubMed1980

Three-dimensional organization of the rat parathyroid glands.

For the study of the three-dimensional organization of the rat parathyroids, some glands were freeze-fractured and others were mechanically dissociated. The main element of the parenchyma, the epithelial cords, corresponds to folds of an unistratified epithelium; the lateral cell surfaces are studded with microvilli and microplicae and the blood capillaries show irregularly sized fenestrations.

Animals↗
PubMed1978

[Scanning electron microscopic study of the changes of the luminal surface of rat thyroid epithelial cells following exposure to cold for 6 to 48 hours (author's transl)].

Scanning electron microscopic observations of thyroid follicle cells of rats exposed to 4 degrees C for 6 to 48 hours were found to show an increased number of apical microvilli in comparison to those of controls kept at 22 degrees C. These ultrastructural differences--which were statistically significant 48 hours after start of the experiments--are related to stimulation of thyroid gland activity by exposure to cold.

Animals↗
PubMed1978

[Scanniing electron-microscopic study of vascular distribution in the choriocapillaris and lamina vasculosa of the rat eye].

The choriocapillaris and lamina vasculosa of the rat eye were injected with methylmethacrylate and their vascular replicas were studied in the scanning electron microscope. There was not outstanding lobular distribution of vessels in the rat choriocapillaris. Their capillaries form a continuous anastomosed network that covers 85-95% of the surface of pigment epithelium. The terminal arteries ramify into many precapillary vessels that present a lacelike network. Advantages and disadvantages of vascular plastic replicas are discussed.

Animals↗