Is P-glycoprotein a sufficient marker for multidrug resistance in vivo? Immunohistochemical staining for P-glycoprotein in children and adult leukemia: correlation with clinical outcome.

Seventy-eight patients: 45 children, 33 adults and 27 normal healthy donors were enrolled in the study. Expression of P-glycoprotein (P-gp) was evaluated with three monoclonal antibodies (MAb's) directed to intra-(C219, JSB-1) and extra-cellular (MRK-16) epitopes of P-gp and immunocytochemical (IC) APAAP staining method. Twenty-seven healthy donors peripheral blood mononuclear cells (PBMC) were investigated by means of IC and FACScan analysis. Positive staining for P-gp was detected in 31% children's and 33% adults' leukemia samples. No reactivity of three MAb's was observed with peripheral blood mononuclear cells (PBMC) by means of IC. Flow cytometry analysis with C219 MAb revealed staining for P-gp present on sub-population of lymphocytes and monocytes. P-gp (+) as well as P-gp (-) cases were compared in respect to clinical outcome, FAB classification and blood group. Complete remission (CR) was achieved in 12/14 (85%) children's and 9/11 (81%) adults' P-gp (+) leukemia cases. Within the P-gp (-) leukemia cases CR was observed in 24/29 (82%) and 18/22 (81%), respectively. Partial remission, relapse, resistance and death were noticed in 14% children's and 18% adults' P-gp (+) samples. In P-gp (-) cases these parameters were observed in 17% and 18%, respectively. These results raise the question whether the expression of P-gp can be used as single prognostic marker to detect multidrug resistance (MDR phenomenon) in vivo?

Effect of soluble complement receptor-1 on neutrophil accumulation after traumatic brain injury in rats.

As part of the acute inflammatory response, neutrophils accumulate in the central nervous system after injury. Recently, a soluble human recombinant complement receptor (sCR1; BRL 55730; T Cell Sciences, Inc., Cambridge, MA, U.S.A.) has been developed that inhibits the activation of both the classical and the alternative pathways of complement. sCR1 attenuates the effects of the acute inflammatory response in several models of injury outside the central nervous system. The role of complement in traumatic brain injury, however, remains undefined. We hypothesized that treatment with sCR1 would attenuate neutrophil accumulation in the brain after cerebral trauma. Using a randomized, blinded protocol, 18 anesthetized Sprague-Dawley rats were pre-treated with sCR1 or saline (control) at both 2 h and 2 min before trauma (weight drop) to the exposed right parietal cortex. A third dose of sCR1 (or saline) was given 6 h after trauma. Coronal brain sections centered on the site of trauma were obtained at 24 h after trauma and analyzed for myeloperoxidase (MPO) activity as a marker of neutrophil accumulation. Complete blood counts with differential were obtained before treatment with sCR1 and at 24 h after trauma. At 24 h after trauma, brain MPO activity was reduced by 41% in sCR1-treated rats compared with control rats [0.1599 +/- 0.102 versus 0.2712 +/- 0.178 U/g (mean +/- SD); p = 0.02]. The neutrophil count in peripheral blood increased approximately twofold in both groups. Neutrophil accumulation occurring in the brain after trauma is inhibited by sCR1 treatment. This suggests that complement activation is involved in the local inflammatory response to traumatic brain injury and plays an important role in neutrophil accumulation in the injured brain.

Neutrophil accumulation after traumatic brain injury in rats: comparison of weight drop and controlled cortical impact models.

Previous work in our laboratory and others using the weight drop (WD) model of traumatic brain injury (TBI) has shown that neutrophils accumulate in brain tissue during the initial 24 h posttrauma as measured by myeloperoxidase (MPO) activity and immunohistochemistry. This study compares the acute inflammatory response to TBI over time, as measured by MPO activity, in the WD and controlled cortical impact (CCI) models. Anesthetized adult Sprague-Dawley rats were traumatized using WD (10-g weight dropped 5 cm) or CCI (4 m/sec, 2.5 mm depth). At 2, 24, 48, or 168 h after trauma, rats (n = 4-5/group at each time) were anesthetized and killed, the brains were removed, and 6-mm coronal slices from traumatized and contralateral hemispheres were assayed for MPO activity. Nontraumatized rats (n = 4) served as controls. Three additional rats underwent a more severe CCI (3 mm depth) with MPO activity assayed at 24 h. A separate group of rats (n = 6) was subjected to WD trauma and killed at 2 weeks after injury for analysis of lesion volume. MPO activity in the traumatized hemisphere was demonstrated at 24 and 48 h in both the WD (0.3152 +/- 0.0472 and 0.3017 +/- 0.0228 U/g, respectively, p < 0.05 vs controls) and CCI (0.1866 +/- 0.0225 and 0.1937 +/- 0.0772 U/g, respectively, p < 0.05 vs controls) models. MPO activity was below the sensitivity of the assay in the control, 2 h, and 168 h groups in both models.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of EBV encoded latent membrane protein 1 (LMP-1) and bcl-2 protein in childhood and adult Hodgkin's disease: application of microwave irradiation for antigen retrieval.

Surgical biopsies obtained from 32 children, and 34 adults with Hodgkin's disease (HD) were investigated for the expression of the EBV encoded Latent Membrane Protein 1 (LMP-1), bcl-2 protein, markers for HD; LeuM1 (CD15), BerH2 (CD30) and the new BLA.36, as well as for B (L26) and T lymphocytes (UCHL1). Before immunostaining, sections were subjected to an Antigen Retrieval (AR) procedure based on microwave irradiation in citrate buffer. In 13 cases staining with and without the AR procedure was compared. Immunoreactivity for LMP-1 was found in 44% of the biopsies from adults and 53% from children. We also found reactivity for the bcl-2 protein in Hodgkin's and Reed Sternberg (HRS) cells in 48% of the biopsies from adults and 45% from children. Immunoreactivity with BLA.36 was found in 94% of the biopsies from adults and 100% from children, with LeuM1 in 83% from adults and 93% from children and with BerH2 in 24% from adults and 84% from children. Nuclear PCNA staining was seen in HRS in all cases both adult and childhood. The T cell marker (UCHL1) displayed no reactivity with HRS cells. In 21% of the adult and 9% cases from the childhood cases we observed reactivity with the B cell marker (L26) in HRS cells. We can conclude that antigen retrieval improves immunostaining results of paraffin sections which were previously negative for bcl-2, LeuM1 and BerH2 antibodies. The high percentage of LMP-1 positive cases, both in adults and in children, indicates that the potential pathogenetic effect of EBV may be of similar importance both in childhood and in adult HD. The new MAb BLA.36 gave consistent immunostaining with HRS cells but also with other cell types. In a panel of markers for HRS cells BLA.36 together with LeuM1 (CD15) and BerH2 (CD30) are useful.

[Is standardization possible in immunohistochemical examination?]. / Czy mozliwa jest standaryzacja w badaniach immunohistochemiczynch.

Immunohistochemistry has become an important tool in research and in surgical pathology. Rapid growth of a new methods in immunohistochemistry supplement traditional histochemical and histological light microscopy investigations. Immunohistochemistry has given pathologists a chance to location different antigens on the cell surface as well as in the cell compartments. The expression of antigens are mostly influenced by factors connected with tissue processing; fixation and embedding. The aim of present article is to show the role of these factors and their influence on some immunohistochemical staining results. Not all the problems are discussed here, the main goal which authors would like to obtain is to show the way how to solve problems which can occur during immunohistochemical staining procedure. They want also to delineate the importance of standardization in immunohistochemistry to make the results more reliable between different laboratories.

[P glycoprotein and multidrug resistance]. / P-glikoproteina a opornosc wielolekowa.

Drug resistance has been shown to be associated with the expression of P-glycoprotein (P-gp), the product of mdr-1 gene. One of the suggested mechanisms for the phenomenon called Multidrug Resistance (MDR) is related to the overexpression and amplification of the mdr-1 gene. The product of this gene is called P-gp and it has been considered as a potential marker for drug resistance. Transfection of the mdr-1 gene into drug-sensitive cells confers the role of mdr-1 gene in developing MDR phenotype. Structural analysis of homologous cDNA, responsible for production of transport proteins, from: MDR cell lines, bacteria and yeast, revealed high similarity. Molecular structure analysis indicate that P-gp has nucleotide binding sites. It has been established that P-gh has an internal ATP-ase activity, thus it can act as energy dependent transport protein. The expression of P-gp has been found in neoplastic and normal tissues (as adrenal glands, kidney, liver, pancreas, jejunum and large intestine), as well as in several cell lines which have been induced to become resistant to cytostatics. The aim of present study was to review the role of P-gp expression in laboratory and clinic.

Expression of P-Glycoprotein in Non-Hodgkin's Lymphomas.

Drug resistance has been shown to be associated with the expression of P-glycoprotein (P-gp), the product of the mdr-1 gene. In the present study the expression of P-gp in 57 cases B-cell non Hodgkin lymphoma NHL was assessed before chemotherapy. Six cases of reactive lymphoid tissue and 11 cases of solid tumors were also studied. The expression of P-gp was evaluated by immunocyto- and histochemical methods, using three different Monoclonal Antibodies C219, JSB-1 and MRK16 directed against separate epitopes of P-gp. Comparable frequencies of cases positive for P-gp were found in low grade (6/40) and high grade (3/17) lymphomas. The pattern of staining was predominantly cytoplasmic, although a Golgi-associated dot like pattern of staining was also seen, mostly with JSB-1 MAb. Both cases of Hairy cell leukemia were P-gp positive. P-gp expression was also found in the endothelium of small capillaries and some high endothelial venules, as well as in macrophages, in both lymphomas and reactive lymphoid tissues. P-gp expression was found in a low frequency in NHL, suggesting that clinical drug resistance may already be predicted at the time of diagnosis and thus may serve as a guide in the choice of chemotherapeutical regiment.