Control of emission spectra in quantum dot microdisk/microring lasers.

Focused ion beam is applied to quantum dot based microresonators to form pits or groove on their surface. The emission spectra of the resonators based lasers are significantly thinned out after the ion beam milling, and one or two modes become dominant instead of a group of modes having comparable intensities. The linewidth of the lasing mode is kept unchanged, whereas the lasing threshold demonstrates an insignificant growth.

Mannose 6-phosphate/insulin-like growth factor II receptor is a death receptor for granzyme B during cytotoxic T cell-induced apoptosis.

The serine proteinase granzyme B is crucial for the rapid induction of target cell apoptosis by cytotoxic T cells. Granzyme B was recently demonstrated to enter cells in a perforin-independent manner, thus predicting the existence of a cell surface receptor(s). We now present evidence that this receptor is the cation-independent mannose 6-phosphate/insulin-like growth factor receptor (CI-MPR). Inhibition of the granzyme B-CI-MPR interaction prevented granzyme B cell surface binding, uptake, and the induction of apoptosis. Significantly, expression of the CI-MPR was essential for cytotoxic T cell-mediated apoptosis of target cells in vitro and for the rejection of allogeneic cells in vivo. These results suggest a novel target for immunotherapy and a potential mechanism used by tumors for immune evasion.

Cytotoxic T lymphocyte-assisted suicide. Caspase 3 activation is primarily the result of the direct action of granzyme B.

Cytototoxic T lymphocyte-induced apoptosis can occur either through the directed exocytosis of granzyme B and perforin or via ligation of Fas. Both pathways involve the activation of a family of cysteine proteinases, the caspases, that cleave substrates at aspartic acid and are themselves activated by cleavage at internal aspartate residues. Fas recruits caspase 8, which initiates the death program through the subsequent activation of caspase 3. Granzyme B can process both caspase 8 and 3 in vitro, suggesting that both Fas and granzyme B access the apoptotic program in the same way. Here we demonstrate that although the two mechanisms are similar, the events that lead to activation of caspase 3 can be distinguished in vivo on the basis of their sensitivities to both pharmacological and virus-encoded caspase inhibitors. In cytotoxic T lymphocytes-mediated death the initial cleavage event on caspase 3 is insensitive to benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone (zVAD-fmk) inhibition in both mouse and human systems. During Fas-mediated death, however, activation of caspase 3 is completely inhibited to zVAD-fmk. In addition, the viral serpin SPI-2, a homologue of cytokine response modifier A (crmA), is an effective inhibitor of the Fas but not the granzyme pathway. Our results demonstrate that whereas Fas-mediated activation of caspase 3 requires an upstream caspase activity that is zVAD-fmk-sensitive, the initial cleavage of caspase 3 during granule-mediated cell death is insensitive to zVAD-fmk, suggesting that caspase 3 is cleaved directly by granzyme B in vivo.

[Mechanisms of the negative effect of blood serum on iodine-131 uptake by cultured thyrocytes]. / Deiaki mekhanizmy negatyvnogo vplyvu syrovatky krovi na poglynannia iodu-131 kulturoiu tyreotsytiv.

Embryonal (calf) and ordinary (cattle) blood sera have ben studied experimentally on a primary culture of thyroid cells from newborn pigs for their effect on basal and thyrotropin (TSH)-stimulated 131I uptake by thyrocytes. It is shown that the value of this index is inversely proportional to the relative percentage of the blood serum in the cultivation medium. The concentrations being equal, the ordinary blood serum effect is more pronounced than the embryonic one. Thyrocyte incubation in a medium with 1% blood serum and 0.1-10.0 mU/ml TSH stimulates 131I uptake by the cells, whereas 15% concentration of the blood serum blocks the influence of this hormone. Ouabain (0.1 mM) and cyclohexamide (10 micrograms/ml) have also an inhibiting effect on exposure of the basal and TSH-stimulated uptake of the isotope. It is suggested that the blood serum contains biologically active substances inhibiting the transmembranous transfer of iodides into thyrocytes. This process is controlled by Na+, K(+)-ATPase, and its TSH-stimulation is mediated by protein synthesis de novo.

[Study of the morphofunctional properties of cultured thyrocytes of newborn piglets with the purpose of determining the feasibility of their use for compensation of thyroid gland hypofunction]. / Izuchenie morfofunktsional'nykh svoistv kul'tiviruemykh tirotsitov novorozhdennykh porosiat s tsel'iu opredelniia vozmozhnosti ikh primeneniia dlia kompensatsii gipofunktsii shchitovidnoi zelezy.

The method for cultivation has been developed and morphofunctional characteristics of the newborn piglet thyrocytes studied in order to elucidate the possibility of using these cells for the compensation of the thyroid gland hypofunctioning. The results evidence viability of the cultivated thyrocytes and intactness of their thyroxine-secreting activity within 14 days. Addition of thyrotropin to the medium resulted in the accrement in the population of the active hormone-producing and follicle-producing cells, in reduction of the number of degenerating and pyknotic forms, in stimulation of thyroxine secretion, incorporation of 3H-leucin in thyrocyte protein, and in absorption and organification of 131I by these cells, this being the specific function of this gland, providing the adequate synthesis of thyroid hormones. The resultant thyrocyte culture may be used in clinical transplantology for the treatment of hypofunctional states of the thyroid.

[The effect of biologically active substances from the spleen on the content of somatotropic hormone in the rat hypophysis]. / Vliianie biologicheski aktivnykh veshchestv selezenki na soderzhanie somatotropnogo gormona v gipofize krys.

The influence of splenin, a "splenic protein-free extract", and splenectomy on the somatotropic hormone content in the rat pituitary were investigated. It was established that the concentration of this pituitary hormone was only decreased after "protein-free extract" administration. It was suggested that the detected effect was due to peptides incorporated in the preparation composition.

[Somatotropin-synthesizing activity of the in vitro cultured adenohypophyses of intact, hypo- and hyperthyroid rats]. / Somatotropinsinteziruiushchaia aktivnost' kul'tiviruemykh vne organizma adenogipofizov intaktnykh, gipo- i gipertireoidnykh krys.

Somatotropin-synthetizing activity of the adenohypophyses cultivated in vitro in eu-, hupo- and hyperthyroid rats was investigated. The most pronounced persistence of the activity (89%) within 12 days is seen in the adenohypophyses of hypothyroid rats and less evident (41%) in the adenohypophyses of hyperthyroid animals in comparison with that of euthyroid rats (66%). The activity rise in the adenohypophyses of euthyroid hypothyroid rats is observed by the 6th day of cultivation, being more pronounced in the adenohypophyses of hypo- than euthyroid animals. The adenohypophyses cultivated in vitro in hypo- and hyperthyroid rats may serve as models for studying the adenohypophyseal somatotropic function disorders in hypo- and hyperthyroses.

[Somatotropic function of the adenohypophysis in hyperthyroidism]. / Somatotropnaia funktsiia adenogipofiza pri gipertireoze.

Changes in the adenohypophyseal somatotropin function and the site of their origin were studied in experimental rats with hyperthyrosis. It was determined that the adenohypophyseal somatotropin content and biosynthesis were sharply reduced. After repeated somatotropin injections these indices remained unchanged. In vitro the somatotropin-releasing activity of the hypothalamic extracts off hyperthyroid rats is enhanced, whereas somatotropin release into the medium, obtained from the adenohypophyses of hyperthyroid animals, is lowered under the extract effect. It is concluded that a decrease in the adenohypophyseal somatotropin function is caused by loss of somatotropic cell sensitivity to the action of the hypothalamic regulation factors.

[Determination of somatotropin and prolactin by dodecyl sulfate polyacrylamide gel electrophoresis]. / Opredelenie somatotropina i prolaktina dodetsilsul'fat-élektroforezom v poliakrilamidnom gele.

Definite separation of somatotropin and prolactin using sodium dodecylsulphate polyacrylamide gel electrophoresis takes place in continuous systems with pH 7.0-7.2 containing acetate or chloride monovalet anions; substitution of the ions by polyvalent phosphate or borate anions interfered with the separation. The hormones precipitated by trichloracetic acid may be separated and quantitatively determined after dissolving in the weak alkaline solutions. The hormones are distinctly separated from serum proteins and may be quantitatively determined in media containing up to 15% of serum.