PubMed Health⌕ Search

Biomedical subjects

K Malinowski

Publications and source records attributed to K Malinowski.

At least 19 recordsLinked to original sources
PubMed1992

Modulation of human lymphocyte marker expression by gamma irradiation and mitomycin C.

gamma irradiation (GR) or mitomycin C (MC) treatment of stimulator cells is frequently used to achieve unidirectionality of response in the mixed lymphocyte reaction. As GR differs from MC in the pathways used to block lymphocyte replication, this study analyzes the effects of these modalities upon the expression of various differentiation and Class II major histocompatibility antigens on lymphocytes cultured for 24, 48, and 72 hr. There was a decrease in the mean density of HLA-DR expression on CD3+ and on CD8+ cells at 24, 48, and 72 hr after exposure to GR (42 and 35, 60 and 69, and 26 and 49%, respectively) or to MC (26 and 11, 26 and 18, and 46 and 30%, respectively). There was a parallel decrease in the levels of the corresponding cell subsets when compared with control cultured cells not exposed to GR or MC. In contrast, the density of HLA-DR markers on CD3-negative cells was increased at 24, 48, and 72 hr of culture following exposure to GR (73, 82, and 102%, respectively) or to MC (9, 45, and 80%, respectively). There was a more profound decrease in CD3+, CD8+, and CD19+ cell subset levels and in the density of the corresponding markers in GR-treated cells than in those of cells exposed to MC when the results were compared with those of untreated cultured control cells. Although GR appears to exert a more profound effect than MC, the results indicate that both modalities have the capacity to reduce the density of polymorphic determinants on Class II (HLA-D region)-encoded molecules on T (CD3+ and CD8+) and B (CD19+) cells which are known to trigger potent MLR responses. Both modalities may therefore affect profoundly the relative strength of MLC responses and the derived measurements of the degree of HLA Class II compatibility between stimulator and responder cells.

Antigens, CD↗
PubMed1992

Homing of CD8CD57 T lymphocytes into acutely rejected renal allografts.

This study compares the cellular events in excised rejected renal allografts (RKT), with concurrent data in the peripheral blood (PB) in the same patients. The kidney transplants were obtained from recipients after rejections crises that were refractory to treatment. Two-color flow cytometry data was used for quantitation of cell subset profiles and quantitation of the density of individual lymphocyte surface antigen(s). The level of CD3DR-positive T cells in RKT was significantly higher than in PB. This difference ranged from 3 to 19-fold increases. There was an even more pronounced increase in CD8CD57 cell subset levels in RKT versus PB. In parallel with these findings, there was a 15-fold greater mean density of the CD8CD57 markers on T cells in RKT, when compared with the same cells in PB. The density of CD8 and of DR markers on CD3+ cells was also significantly higher (4-fold in each instance) in RKT. These data point to a homing of CD8CD57 cells with corresponding increases in the density of these markers in acutely rejected renal allografts, with only a relative decrease of this cell subset in peripheral blood. The appearance of a high preponderance of CD8CD57 cells in the renal allograft at the time of a rejection crisis may constitute a particularly severe prognostic sign regarding the reversibility of the response after treatment with steroids and/or monoclonal antibodies.

Acute Disease↗
PubMed1991

Quantitative analysis of surface marker densities after exposure of T-cells to concanavalin A (Con A): a sensitive early index of cellular activation.

The kinetics of expression of activation-linked T-cell surface markers were analyzed in T-cells obtained from normal donors. The cells were cocultured in triplicate for 0, 1, 24, 48, and 72 hr in the presence of Con A in RPMI 1640. The density of HLA-DR, interleukin 2, and transferrin receptors (IL-2-R and TR, respectively) on the surface of CD3- and CD8-positive cells was computed by a mathematical model based on fluorescence intensity vector analysis, adjusted for cell size, utilizing two-color flow cytometry. The results were compared with controls obtained at the same time with control cells cultured in RPMI 1640 alone. There was a significant increase in the mean density of HLA-DR on the surface of CD3- and CD8-positive cells as early as 1 hr after exposure to Con A when compared with controls (250 and 300%, respectively; P less than 0.0001). The mean density of IL-2-R and TR on CD3+ cells increased by 265 and 208%, respectively; P less than 0.06 and P = n.s., respectively, when compared with control cells. The mean density of Class II MHC products on CD3+ and CD8+ cells treated with RPMI alone increased by 202 and 468%, 234 and 540%, and 1375 and 2442%, respectively, at 24, 48, and 72 hr of culture. In contrast, the mean cell surface density of these markers in cells treated with Con A increased by 614 and 1962%, 3304 and 7231%, and 8665 and 22,619%, respectively (P less than 0.00001) at the corresponding times following exposure to Con A. The density of IL-2-R and TR on CD3+ cells exposed to Con A also increased significantly at 24, 48, and 72 hr (P less than 0.0001). At the same times, the relative percentage of cell subsets bearing these particular markers increased by 78, 138, and 175% at 24, 48, and 72 hr, respectively. The data suggest that objective quantitative evidence of lymphocyte activation after exposure to Con A may be obtained as early as 1 hr after antigen stimulation, and before significant changes in cell numbers occur. Measurement of cell surface marker densities may provide a useful index for the detection and quantitation of cell activation in the early phase of antigenic stimulation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Prognostic significance of T cell associated surface antigen density changes during OKT3 therapy of renal allograft rejection.

We describe 12 acute rejection episodes in 11 cadaver donor renal allograft recipients who required OKT3* rescue treatment for steroid-resistant acute rejection (9) or for severe vascular (antibody-mediated) rejection (3). There were 3 treatment failures with subsequent graft loss. Using 2-color flow cytometry the total T (CD3), B (DR+), activated T (CD3DR), T helper/inducer (CD4), T cytotoxic/suppressor (CD8) and activated T cytotoxic cell (CD8DR) subsets were analyzed before, in mid course (5 to 7 days) and at the end of 12 to 14 days of therapy with 5 mg. OKT3 intravenously daily. In parallel changes in the density of such T cell associated antigens were analyzed. Significant decreases in the mean levels of the CD3 (p less than 0.001), CD3DR (p less than 0.05), CD4 (p less than 0.05), CD8 (p less than 0.05) and CD8DR (p less than 0.05) subsets were observed at mid course. A significant decrease in the density of CD3 was observed (p less than 0.0001). The surface antigen density of CD3DR, CD4 and CD8 had decreased by 160% (p less than 0.002), 383% (p less than 0.001) and 260% (p less than 0.001), respectively. At the end of treatment CD3 and CD4 subset levels increased by 425% and 240% (p less than 0.001 and p less than 0.005), respectively. In contrast, the CD3DR and CD8DR subset levels continued to decrease (p less than 0.05). A higher pre-treatment level of CD3DR and a less sharp decrease in CD3, CD4 and CD8 subsets were associated with a higher risk of treatment failure (p less than 0.05, p less than 0.01, p less than 0.05 and p less than 0.05, respectively). The mean decrease in the density of the CD3 marker in the lost grafts was significantly smaller compared to successful outcomes (p less than 0.001). The results of this preliminary study suggest that OKT3 affects T cell associated antigens other than CD3. Such may provide a sensitive prognostic index for the effectiveness of OKT3 therapy, and permit the identification of those patients who might require higher doses and/or duration of OKT3 therapy to enhance renal allograft salvage rates.

Antibodies, Monoclonal↗
PubMed1988

Lens alpha-neoproteins.

The formation of lens alpha-neoprotein molecules which are built by the association of A and B subunit chains of alpha-crystallin but have a different quaternary structure than the native protein is a posttranslational process that progresses through the life span. Alpha-neoproteins occur regularly in all mature mammalian lenses tested. The mechanisms that have been identified for the formation of alpha neoproteins are imbalance in the biosynthesis of A- to B-chains, which leads to a ratio of less than 2A-chains to 1B-chain, and derivation of the chains after their initial association into native alpha-crystallin. In terms of quantity of neoproteins, no significant differences have been found between lenses with developing cataracts and normal control lenses of corresponding age. The possibility that there are structural differences between alpha-neoproteins in normal and cataractous lenses of the same age, as well as potential differences among alpha-neoproteins isolated from normal lenses of different ages, are presently under investigation.

Animals↗
PubMed1988

Age-dependent effect of UV light in abnormal alpha neoprotein formation in the lens.

The aim of this study was to determine whether or not alpha neoprotein formation can occur in the lens in response to a photolytic process. Alpha crystallin from young calf and aged bovine lenses was irradiated for up to 22 hours with UV light. After cortical alpha crystallin had been irradiated, it completely preserved its quaternary antigenic determinants. In contrast, 24.3% of the bovine nuclear alpha crystallin completely lost their quaternary determinants as a result of irradiation. The latter population of molecules still preserved the association of A chains with B chains, suggesting the formation of abnormal proteins. The exposure to UV irradiation can cause the formation of alpha neoproteins from aged but not from young alpha crystallin. Comparison of photolytic rates based on spectroscopic and chromatographic parameters also show an age-related increase in the susceptibility of alpha crystallin to photolyze. It is suggested that this increase is due to the age-related formation of a photosensitizer in alpha crystallin.

Aging↗
PubMed1986

Daily rhythm of cortisol, and evidence for a photo-inducible phase for prolactin secretion in nonpregnant mares housed under non-interrupted and skeleton photoperiods.

Studies were conducted in anestrous mares to characterize daily rhythms of cortisol in non-interrupted [ambient and 16 h light (L): 8 h dark (D)] and skeleton (10L:4D:2L:8D, 10L:6D:2L:6D and 10L:8D:2L:4D) photoperiods, and to determine if there exists a photosensitive phase for the secretion of prolactin. Neither peak or nadir concentrations of cortisol, nor the time of peak or nadir concentrations differed among photoperiod treatments. Highest concentrations (66 +/- 4.4 ng/ml, mean +/- SE) occurred between 0700 and 0900, whereas lowest concentrations (31 +/- 3.6 ng/ml) were found from 1900 to 2300. Mean daily concentrations of serum prolactin were significantly higher in mares housed under the 16L:8D and the 10L:8D:2L:4D photoperiods as compared with the remaining photoperiod treatments, and were lowest in the ambient photoperiod treatment. The mean daily concentration of prolactin in February among photoperiod treatments was inversely related to the number of days (from December 1) to first seasonal ovulation (r = -.92, P = .027). The results were interpreted to: 1) suggest that mares in the 10L:8D:2L:4D skeleton photoperiod do not phase-shift to interpret the 2-h light pulse as the beginning of their subjective day; and 2) provide further evidence that the photo-inducible phase for both prolactin secretion and the stimulation of seasonal reproductive activity occurs 8 to 10 h following the onset of the dark period (scotophase).

Animals↗
PubMed1985

Alpha neoprotein molecules in normal lenses from animals of different ages and in cataractous lenses.

Alpha neoprotein molecules are formed by an association of A and B subunits resulting in a different quaternary structure than in alpha crystallin. The content of alpha neoprotein vs. alpha crystallin was estimated separately on the crystallin, cryoprotein and albuminoid fractions in lenses of animals of different species and ages, in lenses with experimentally induced cataracts and in human cataractous lenses. Alpha crystallin was determined on immunoadsorbents with bound antibodies restricted to quaternary determinants of this protein. Alpha neoprotein molecules were determined in the filtrate containing lens proteins not bound on the above immunoadsorbent. The filtrate was applied on an anti-A chain immunoadsorbent, and after desorption the A chain-containing molecules were applied on an anti-B chain immunoadsorbent. The amount of lens proteins bound to the latter immunoadsorbent gave a measure of molecules formed by an association of A with B chains other than in alpha crystallin, that is of alpha neoproteins. No alpha neoprotein was present in lenses from 2-week-old rats or in the 3- to 6-month-old calf lens cortex. The 2-year-old bovine lens nucleus did contain alpha neoproteins, but only in the albuminoid fraction. The lenses of adult rats (i.e. 3- to 4-month-old) contained alpha neoprotein molecules mainly in the albuminoid fraction; small amounts were also found in the cryoprotein fraction. All three fractions of lens proteins from 1-year-old rats contained alpha neoprotein molecules. No significant differences in the content of alpha neoprotein molecules were found in lenses with experimentally induced X-ray and galactose cataracts and in normal controls. This finding does not exclude possible structural differences between normal and cataractous alpha neoproteins. In human senile cataractous lenses, the content of alpha neoprotein molecules in all fractions analyzed equaled or exceeded the content of alpha crystallin present. The present findings demonstrate an age-dependent formation in the mammalian lens of alpha crystallin neoproteins lacking native quaternary determinants. The data obtained point to the possibility that the structural lability of alpha crystallin may be a contributing factor in cataractogenesis.

Aging↗
PubMed1985

Effects of interrupted photoperiods on the induction of ovulation in anestrous mares.

The ability of interrupted photoperiods to induce early estrus and ovulation was examined. Horse mares were exposed to long (16 h light) or short (10 h light), noninterrupted photoperiods, ambient light, or various interrupted photoperiod treatments from December 1 to April 15 (135 d). Follicular development was assessed by rectal palpation and estrous behavior was determined by teasing with a stallion. Serum concentrations of progesterone were used as an indicator of corpus luteum function. Differences among the light treatment groups were compared for the following behavioral and ovarian characteristics: days to first detectable 3-cm follicle, days to first estrous behavior, days to first ovulation, the number of mares ovulating within the treatment period, and the number of ovulations within the treatment period per mare. Compared with the ambient and 10L:14D (L = h of light and D = h of darkness) photoperiod treatments, ovulation was advanced to the greatest extent by a photoperiod of 16L:8D and the interrupted photoperiod 10L:8D:2L:4D. These two stimulatory photoperiod treatments were characterized by the presence of light 8 to 10 h after dusk. Therefore, the present data are consistent with an external coincidence model for the induction of seasonal breeding in horses, with the photoinducible phase occurring within the period 8 to 10 h after dusk.

Animals↗
PubMed1979

The relative capacity of corneal, heart, kidney and skin cells to stimulate allogeneic lymphocytes.

In stimultaneous experiments, the ability of inbred Wistar-Furth rat corneal cells to stimulate inbred Fisher rat lymphocytes in mixed culture was compared with the stimulatory capacity of the same number of Wistar-Furth skin, kidney, heart and lymphocyte cells. The tissue cells were dissociated and after inhibition by mitomycin C cultured with an equal number of allogeneic spleen lymphocytes for 5 days. In all of these mixed cell cultures, the allogeneic lymphocytic response was mainly to the major Ag-B2 histocompatibility antigen. The stimulatory effect of corneal cells was found to be the same as that of heart, kidney and skin cells. The data indicate a lack of differences between the density of histocompatibility antigens on the surfaces of these cells.

Animals↗
PubMed1978

A micro-procedure for quantitative precipitin tests.

A new method for the quantitative analysis of antigens and antibodies has been based on (1) ultrafiltration of the antigen-antibody precipitates through silver membranes of 0.2 micrometer pore size in a specially designed multisample apparatus, and (2) spectrophotometric determination at 210 nm of the amount of proteins in the antigen-antibody precipitates dissolved in 0.01 N HCl. At this wavelength, the = C = O group of the polypeptide chains constitutes the main chromophoric group. In comparisons with the ninhydrin color reaction, protein determination by low UV spectrophotometry, e.g., at 210 nm, was shown to be about 6 times more sensitive, permitting analysis of samples containing from 1.0 to 35.0 microgram of antigen. The concentration range of protein solutions in 0.01 N HCl which is measured at low UV can be regulated by a factor of 8--10 by changing absorption between 200 and 230 nm. Comparison of the ultrafiltration microtechnique with the standard quantitative precipitin microtechnique involving centrifugation of precipitates was made in 4 different antigen-antibody systems. The new technique was found to be as accurate as the standard technique. It allows completion of analysis within only 5--6 h. The standard precipitin technique, by contrast, requires a 5--7-day reaction period for completion.

Animals↗
PubMed1978

The distribution and relative immunogenicity of calf alpha-crystallin antigenic determinants on different subunits.

In the native alpha-crystallin molecule, 45.9% of all reactive antigenic determinants were found to be located on SH-containing subunits. Of these, the majority (35.3%) were reaggregation dependent, and 10.6% were reactive on monomeric subunits. By contrast, only 10.9% of all antigenic determinants were located on SH-free subunits, and the ratio of aggregation-dependent determinants (4.4%) to those of monomeric subunits (6.5%) was reversed compared to SH-containing subunits. Among all antigenic determinants reactive in native alpha-crystallin, 44.1% were dependent on the presence of both types of subunits. These data indicate that the antigenic determinants requiring subunit interaction were formed from SH-containing and SH-free subunits in a ratio of 1:1. Direct analysis showed that in the alpha-crystallin molecule, the ratio of these subunits is 2:1. The experiments indicate that some conformations of subunits in the native molecule persist in separated subunits. The relative immunogenicity of each type of antigenic determinant expressed as the ratio of the percentage of the determinant reactive in the native calf lens alpha-crystallin to the percentage of corresponding antibodies induced by native alpha-crystallin was found to be close to 1.

Animals↗