Polarization temporal dynamics in a dye microlaser

We have investigated the temporal dynamics of the output polarization of a dye microlaser operating in a transient regime, i.e., under femtosecond excitation. In these conditions the dipole angular diffusion has an important role in the formation of the microlaser pulse, as is shown in a theoretical model. By performing the experiment for different values of the microcavity length and varying the polarization angle, we measured threshold and buildup time of the microlaser and compared the results obtained with two dye solutions of different viscosity. The agreement between theory and experimental results is adequate.

New cytotoxic steroids from the marine sponge Dysidea fragilis coming from the lagoon of Venice

The sterol composition of the sponge Dysidea fragilis, coming from the lagoon of Venice, has been investigated; our results confirmed the variability of D. fragilis biochemistry. The sponge elaborates, in addition to eight usual 3 beta-hydroxy sterols, thirteen polyhydroxysterols, eight of them (6-13) were novel compounds. Their structures were established by spectroscopic data. New compounds 3 beta,5 alpha,6 beta,7 alpha-tetrahydroxy-cholest-8(9)-en-11-one (8), 3 beta,5 alpha,6 alpha-trihydroxy-9,11-secocholest-7-en-9-one (9) and 3 beta,5 alpha,6 alpha,9 alpha-tetrahydroxy-cholest-7-ene-6-sulfate (11) were proved to be cytotoxic on two different tumor cell lines in vitro.

Microcavity transverse coherence length and microlaser threshold

The concept of transverse coherence length in an active microscopic cavity is investigated with regard to the threshold of the microlaser action. This physical parameter is related to the linear spatial extent, or the effective radius, of the transverse lasing mode operating in a plane Fabry-Perot microcavity. This problem is analyzed by means of a full semiclassical theory, by which the microlaser threshold is expressed as a function of the relevant parameters of the thresholdless microlaser and of the extension of the active pumped zone. Experimental results are in satisfactory agreement with the theoretical predictions.

IL-12 inhibits apoptosis induced in a human Th1 clone by gp120/CD4 cross-linking and CD3/TCR activation or by IL-2 deprivation

The aim of our work was to study apoptosis as a possible mechanism of CD4+ lymphocyte depletion in AIDS patients and to test whether IL-12 could limit this phenomenon. As an in vitro model, we used a human IL-2-dependent Th1 clone from an uninfected individual. We found that CD4 cross-linking, obtained either by mouse anti-CD4 mAb plus goat anti-mouse or by recombinant gp120 plus anti-gp120 mAb, followed by activation with immobilized anti-CD3 or anti-TCR mAb, induced apoptosis at early times (15-25% apoptotic cells at 4 hr), whereas IL-2 deprivation required longer times (20-40 hr) to induce apoptosis. Both CD4 cross-linking and IL-2 deprivation-induced apoptosis appeared to be PTK-dependent and were inhibited by either IL-2 or IL-12. Our data suggest that in vivo CD4/gp120 interactions could directly prime the apoptosis of Th1 lymphocytes and that IL-2 and IL-12 could be used to prevent this phenomenon.

Regulation of apoptosis induced by the retinoid N-(4-hydroxyphenyl) retinamide and effect of deregulated bcl-2

The cancer chemopreventive retinoid N-(4-hydroxyphenyl)-all-trans retinamide (HPR) was recently shown by us to have antiproliferative and apoptotic effects on human leukemic cell lines, including those unresponsive to all-trans retinoic acid (ATRA). We have now characterized further the process of HPR-induced cell death. We report that inhibitors of RNA transcription and of protein synthesis, activators of protein kinase C (PKC), inhibitors of tyrosine kinases, Zn++, and the antioxidants acetylcysteine, ascorbic acid, alpha-tocopherol, and deferoxamine suppressed HPR-induced apoptosis. HL60 cells induced toward monocytic differentiation by 1,25 dihydroxyvitamin-D3 [1,25(OH)2D3], but not those induced toward the granulocytic differentiation by ATRA, showed reduced responses to HPR. The transport of HPR by cells with different sensitivity to the retinoid, however, was similar, even after treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), which induces unresponsiveness to HPR. The expression of the apoptosis-related genes bcl-2, p53, and c-myc was examined to determine their role in HPR-triggered cell death. The levels of bcl-2 mRNA were markedly diminished by 24 hours of HPR treatment in all cell lines except in the relatively HPR-insensitive line K422. However, probably because of its long half-life, bcl-2 protein levels were either unchanged or only slightly decreased. Downregulation of p53 mRNA was also observed within 24 hours of HPR exposure in NB4 but not K422 cells, but no changes in the amount of p53 protein were found. Suppression of c-myc transcription was observed in all cells except K422. The protective role of bcl-2 on cell death by HPR was investigated in HL60 as well as 697 pre-B leukemia and Jurkat T-acute lymphocytic leukemia (T-ALL) cells constitutively expressing high levels of bcl-2 proteins due to gene transfer manipulation. Compared with control cells, the onset of apoptosis in these cells with deregulated bcl-2 production was delayed by at least 24 hours. These findings establish that cell death by HPR requires RNA transcription and protein synthesis and is regulated by the activation of PKC. Although changes in bcl-2, p53, and c-myc expression are found in cells treated with HPR, the time-course of these events suggests that HPR-triggered apoptosis is not directly controlled by these genes. Finally, while ectopic overexpression of bcl-2 does not protect cells from death by HPR, it markedly delays its onset.(ABSTRACT TRUNCATED AT 400 WORDS)

Independence of optokinetic nystagmus asymmetry and binocularity in infantile esotropia

OBJECTIVE

Children with congenital esotropia, amblyopia, or early visual deprivation have persistent asymmetric monocular pursuit, as measured by optokinetic nystagmus (OKN), and favor targets moving in a temporal to nasal direction. Previous studies suggest that binocular visual development is necessary for the development of symmetric monocular OKN. We recently treated patients with congenital esotropia with unconventionally early surgery to establish good binocularity. We wished to determine if mature symmetric OKN responses could develop in patients with congenital esotropia following the acquisition of good stereopsis.

METHODS

Electro-oculographic recordings documented horizontal eye movements in response to an electronic OKN stimulus.

PATIENTS

The recordings of three patients with congenital esotropia that had been surgically aligned before age 20 weeks and who had achieved high-grade stereopsis with random dot and Titmus stereographic testing were studied. We compared this group of children with groups of age-matched controls, including the following: (1) three patients with congenital esotropia who underwent surgical alignment after age 6 months and who had no amblyopia but poor stereopsis; (2) three children with accommodative esotropia, good ocular alignment when wearing spectacles, and good stereopsis; and (3) three normal children.

RESULTS

The normal children and those with accommodative esotropia demonstrated normal symmetrical OKN. The patients with congenital esotropia showed poor nasal to temporal OKN regardless of the degree of stereopsis or timing of surgery.

CONCLUSIONS

Our results indicate that good binocularity, as measured by stereopsis, is not sufficient for the development of symmetric OKN in patients with congenital esotropia.

Antibody for detecting p53 protein by immunohistochemistry in normal tissues

AIMS

To establish whether PAb248 recognises human p53 as well as murine p53 and if so, to determine its distribution in normal tissues.

METHODS

The ability of PAb248 to recognise human p53 was established by analysis of the human osteosarcoma derived Saos-2 cell line, which lacks the p53 gene, before and after transfection with p53 cDNA, using western blotting and immunoprecipitation. Immunostaining on normal tissues and cell lines was carried out using an immunoperoxidase technique. The two anti-p53 antibodies PAb 240 and DO-7 were used as controls.

RESULTS

The anti-p53 PAb248 monoclonal antibody stained the Saos-2 cell line after, but not before, transfection with p53 cDNA. Both western blots and immunoprecipitations performed with this antibody revealed a 53,000 molecular weight band. With immunostaining, this antibody detects p53 protein in most lymphoid and human epithelial cells in a cytoplasmic-perinuclear localisation that has not been described before. In the same tissues nuclear staining could be seen in a few scattered cells using the PAb240 antibody. The topographical distribution of wild type p53 was not related to proliferating areas but, rather, to short-lived populations of cells.

CONCLUSIONS

Immunostaining of wild type p53 is demonstrable not only in its nuclear form using antibody PAb240 but also in it common cytoplasmic-perinuclear localisation in normal tissues using the PAb248 monoclonal antibody. This opens up new possibilities for its study in both physiological and pathological conditions.

N-(4-hydroxyphenyl)retinamide induces apoptosis of malignant hemopoietic cell lines including those unresponsive to retinoic acid

N-(4-Hydroxyphenyl)retinamide (HPR) is a synthetic retinoid of particular clinical interest in cancer chemoprevention. We have examined the in vitro effects of HPR on lymphoid and myeloid malignant cell lines and found that at concentrations between 10(-5) and 3 x 10(-7) M it induces a dose-dependent growth inhibition (the peak plasma concentration in patients treated with HPR is 1 to 2 x 10(-6) M). The antiproliferative effect of HPR was, in all cell lines except K422, more potent than that induced by an equimolar dose of all-trans retinoic acid (RA). Also, this effect was irreversible on HL60 and DoHH2 cells that had been exposed to HPR (3 x 10(-6) M) for 24 h, but reversible on Raji and DHL4 exposed to the retinoid for 48 and 72 h, respectively. Time-course growth analysis showed that HPR at 3 x 10(-6) M or below induces a rapid fall of thymidine uptake and viability (> 90%), whereas between 10(-6) and 3 x 10(-7) M exhibits cytostatic effects. Interestingly, the RA-resistant HL-60R and NB306 cells, characterized by a point mutation in the retinoic acid receptor (RAR) and by the loss of the pml/RAR protein, respectively, were, like the parental RA-inducible HL-60 and NB4 cell lines, fully responsive to HPR, thereby suggesting that HPR and RA could act through different receptors or pathways. DNA flow-cytofluorimetric analysis revealed that HPR does not block cells in a specific phase of the cell cycle but triggers programmed cell death or apoptosis. This phenomenon was evidenced both by the visualization, on gel electrophoresis, of fragmented DNA, and by the "in cell" enzymatic labeling of DNA breaks with fluorescent dUTP. With the latter method, apoptotic cells become detectable by 6 h following exposure to 3 x 10(-6) M HPR. Ultrastructural examination of HPR-treated samples showed cells with chromatin compaction and cytoplasm condensation, characteristic of apoptotic cells. In conclusion, our study demonstrates that HPR suppresses malignant cell growth and induces apoptosis at pharmacologically relevant doses. The differential responsiveness by a number of cell lines, especially HL-60R and NB306, to HPR and RA indicates that these compounds may act through different receptors. The clinical use of HPR, particularly in retinoic acid-unresponsive acute promyelocytic leukemia patients, is suggested.

bcl-2 gene hypomethylation and high-level expression in B-cell chronic lymphocytic leukemia

The bcl-2 gene becomes transcriptionally deregulated in the majority of low-grade non-Hodgkin lymphomas as a result of t(14;18) translocations that place the bcl-2 gene at 18q21 into juxtaposition with the Ig heavy-chain locus at 14q32. This chromosomal translocation or similar bcl-2 gene rearrangements involving the Ig light-chain genes have been reported to occur in some cases of B-cell chronic lymphocytic leukemia (B-CLL). We analyzed the structure, methylation, and expression of the bcl-2 gene in 20 cases of B-CLL or closely related variants of this lymphoproliferative disorder, including at least 16 typical examples of CD5+ B-CLL. None of the 20 specimens had evidence of bcl-2 gene rearrangements, based on Southern blot analysis using three different bcl-2 probes. However, immunoblot analysis using antibodies specific for the Bcl-2 protein showed that 14 of 20 cases (70%) contained levels of p26-Bcl-2 that were equal to or greater than those found in a t(14;18)-bearing lymphoma cell line. Furthermore, in 19 of 20 cases (95%), the Bcl-2 protein was present at levels that were 1.7- to 25-fold higher than in normal peripheral blood lymphocytes. These differences in the relative levels of Bcl-2 protein among cases of B-CLL appeared to be functionally significant, in that a preliminary analysis of 3 representative cases showed that CLL cells with higher levels of Bcl-2 protein survived longer in culture and were delayed in their onset of DNA degradation relative to CLL cells with lower Bcl-2 protein levels. Evaluation of the methylation status of the bcl-2 gene using the isoschizomers Msp I and Hpa II, and a probe corresponding to the first major exon of the gene showed complete demethylation of both copies of the bcl-2 gene in a region corresponding to a 2.4-kb Msp I fragment in all 20 cases of B-CLL. In contrast, analysis of 6 of 6 B-cell lines that harbor a t(14;18) was consistent with hypomethylation of only one of the two bcl-2 alleles. Neither copy of the bcl-2 gene was demethylated in this region in 5 of 5 lymphoid cell lines that lack this translocation. However, hypomethylation of the bcl-2 gene did not necessarily correlate with the relative levels of Bcl-2 protein present in the B-CLL cells, suggesting that additional mechanisms for regulating bcl-2 expression are involved.(ABSTRACT TRUNCATED AT 400 WORDS)

[Assessment of portal hypertension in hepatic cirrhosis in relation to etiologic factors]

Hundred-forty-one patients, 78 affected by alcoholic liver cirrhosis and 63 by posthepatitic cirrhosis were studied in order to assess the degree of portal hypertension in liver cirrhosis of different etiology taking into account the developing stages of the disease. Etiological assessment was based on anamnesis, laboratory data, needle liver biopsy and patients of each group were divided into 3 subgroups (grade A, B, C) according to Child-Turcotte classification. A > 1.3 cm diameter of portal vein and a > 13 cm spleen size evaluated by means of real-time ultrasonography together with the occurrence of esophageal varices at endoscopy were considered as signs of portal hypertension. Our study shows that such signs are more frequent in patients affected by posthepatitic cirrhosis in comparison with those affected by alcoholic cirrhosis. If the severity of the disease was considered, at the early stage (grade A) no significant difference was reported in portal diameters while splenomegaly and esophageal varices appeared more frequent in posthepatitic cirrhosis. In grade B patients the increase of portal and spleen size proved significantly greater in posthepatitic cirrhosis whereas prevalence of esophageal varices was similar in the two groups. The lack of differences in the three considered parameters at the end stage of the disease may be due to severe changes in liver morphology actually similar in the 2 groups apart from etiological factors.

CD34 expression is regulated reciprocally with adhesion molecules in vascular endothelial cells in vitro

Freshly cultured vascular endothelial cells express the CD34 antigen in a diffuse cell surface pattern with some concentration on microvilli. Expression is downregulated with proliferation in continuous culture and undetectable after nine population doublings but can be maintained by restraining cell proliferation and promoting cell contact. Expression of CD34 at the antigen and mRNA levels on early passage cells is rapidly downregulated by interleukin-1 beta (IL-1 beta), interferon-gamma (INF-gamma), and tumor necrosis factor-alpha (TNF-alpha) under conditions in which these ligands upregulate the adhesion molecules: endothelial leukocyte adhesion molecule 1 (ELAM-1) and intracellular adhesion molecule 1 (ICAM-1). This reciprocal pattern of expression and the topographic distribution of CD34 molecules on the lumenal interdigitated microprocesses of adjacent endothelial cells in vivo suggest that CD34 might have a negative modulating role on adhesion functions of endothelia.

Articulatory rehearsal and phonological storage in working memory

The theoretical distinction between an articulatory control process and a short-term phonological store was supported in five experiments on immediate serial recall. In Experiment 1, articulatory suppression during the presentation and recall of auditory material abolished the word length effect but not the phonemic similarity effect. In Experiment 2, the two latter effects were found to be independent with auditory presentation. In Experiment 3, the effects of irrelevant speech and word length were found to be independent with visual presentation. In Experiment 4, articulatory suppression during the presentation and recall of auditory material abolished the phonemic similarity effect with a slow presentation rate. Nevertheless, in Experiment 5, articulatory suppression with a conventional presentation rate did not reduce the effect of phonemic similarity, even when a 10-sec interval was interposed between presentation and recall. These results indicate that the encoding, maintenance, and retrieval of spoken material within the phonological store do not depend on a process of articulatory rehearsal.

Community care of corneal ulcers

Because of increasing concern about the appropriate and cost-effective use of eye care services and procedures, several organizations have sought to arrive at practice guidelines or practice patterns from which physicians can draw guidance. To assess the potential effectiveness of such guidelines, we reviewed the care of patients with corneal ulcers. Corneal specialists recommend that cultures be obtained before initiation of treatment. We determined whether ophthalmologists implemented these guidelines by the following: (1) a review of records of 79 patients referred to a tertiary care corneal and external disease service for evaluation of keratitis, and (2) a survey by mail of practicing ophthalmologists. Antibiotic therapy without any cultures was observed in 38 of 79 referred patients with corneal ulcers (48.1%). Our survey of general ophthalmologists disclosed that 274 of 560 patients with corneal ulcers (48.7%) were treated with antibiotics without any cultures being obtained. Compliance with recommended practice in the care of corneal ulcers is poor, as measured with either method. This procedure provides insights into more effective implementation of future practice guidelines.

Histological behaviour of chronic hepatitis in patients treated with alpha interferon

To evaluate the histological effects of alpha Interferon (IFN) therapy, serial liver biopsy specimens from 30 patients with chronic hepatitis were studied. The biopsies were examined using a scoring system. After 12 mths of IFN therapy responders were 8 out of 11 HBV infected patients, 10 out of 12 HCV infected patients and only 1 out of 7 patients with cryptogenetic hepatitis. As spontaneous improvement of hepatic changes is infrequent, our data indicate that in terms of histological patterns interferon therapy is effective in chronic viral hepatitis.

bcl-2 proto-oncogene expression in normal and neoplastic human myeloid cells

The present study provides immunobiochemical and molecular data on the differentiation-linked expression of the bcl-2 proto-oncogene in normal and neoplastic myeloid cells. Using a recently developed monoclonal antibody (MoAb) to the bcl-2 molecule, staining of normal bone marrow myeloblasts, promyelocytes, and myelocytes, but neither monocytes nor most polymorphonuclear cells, was demonstrated. By two-color flow cytometric analysis, bcl-2 was evidenced in CD33+ and CD33+/CD34+ myeloid cells as well as in the more primitive CD33-/CD34+ population. The leukemic cell lines HL-60, KG1, GM-1, and K562 were bcl-2 positive together with 11 of 14 acute myeloid leukemias (AML) and three of three chronic myeloid leukemias (CML) in blast crises; six of seven CML were negative. Among myelodysplastic cases, augmentation of the bcl-2 positive myeloblastic compartment was found in refractory anemia with excess of blasts (RAEB) and in transformation (RAEB-t). Western blots of myeloid leukemias and control lymphocytes extracts evidenced an anti-bcl-2 immunoreactive band of the expected size (26 Kd). Moreover, the HL-60 and KG1 cell lines, both positive for the bcl-2 protein, exhibited the appropriate size bcl-2 mRNA (7.5 Kb). These findings clearly indicate that the bcl-2 gene is operative in myeloid cells and that the anti-bcl-2 MoAb identifies its product and not a cross-reactive epitope. Induction of HL-60 differentiation toward the monocytic and granulocytic pathways was accompanied by a marked decrease in bcl-2 mRNA and protein levels; bivariate flow cytometric analysis showed that the fraction becoming bcl-2 negative was in the G1 phase of the cell cycle. These data establish that the bcl-2 proto-oncogene is expressed on myeloid cells and their progenitors and is regulated in a differentiation-linked manner.

Flow cytometric detection of the mitochondrial BCL-2 protein in normal and neoplastic human lymphoid cells

The bcl-2 proto-oncogene, rearranged and deregulated in B-cell lymphomas bearing the t(14;18) translocation, encodes an inner mitochondrial membrane protein that blocks apoptotic cell death. We have developed a sensitive immunofluorescence assay for the single- and multicolor flow cytometric analysis of bcl-2 protein in relation to other markers and cell cycle, based on a fixation-permeation step of cells with paraformaldehyde and Triton X100 and the use of a bcl-2 specific monoclonal antibody (MoAb). As an application of this method, we have examined the expression of bcl-2 in normal and neoplastic lymphoid cells. We have found that greater than 80% of normal T-and B-cells are bcl-2 positive; following in vitro mitogen activation, the bcl-2 reactivity decreased slightly in the former but markedly in latter cells. In both cases the bcl-2 expression was not restricted to a specific phase of the cell cycle, as evidenced by two-color analysis. On lymphoblastoid cell lines, the bcl-2 staining intensity was variable and not necessarily correlated to molecular rearrangements of the bcl-2 gene. Among fresh B-cell non-Hodgkin's lymphomas (B-NHL), most sporadic Burkitt's cases were bcl-2 negative. Of four centroblastic-centrocytic cases with rearrangements of the bcl-2 gene, only two presented elevated amounts of bcl-2 protein, indicating that the levels of bcl-2 are not diagnostic of the translocation.(ABSTRACT TRUNCATED AT 250 WORDS)

Five new polar sterols from the black coral Antipathes subpinnata

In addition to the known (20S,22E)-cholesta-1,4,22-triene-16 beta,18, 20-triol-3-one, (20S,22E)-24-methyl-cholesta-1,4,22-triene-16 beta,18,20-triol-3-one, and (20S,22E)-24-methylcholesta-4,22-diene-16 beta,18,20-triol-3-one, the methanol extract of the Mediterranean anthozoan Antipathes subpinnata was shown to contain five new sterols: (20S,22E)-cholesta-1,4,22-triene-18,20-diol-3-one, (20S,22E)-24-methylcholesta-1,4,22-triene-18,20-diol-3-one, (20S)-cholest-4-ene-16 beta,18,20-triol-3-one, (20S,22E)-cholesta-4,22-diene- 16 beta,18,20-triol-3-one, and (20S,22E)-24-methylcholesta-4,22-diene-16 beta,18,20-triol-3-one, whose stereostructures were elucidated on the basis of physicochemical evidence. The previously unassigned chirality at C-20 of the known sterols has been also established as S.

Isolation of five new 5 alpha-hydroxy-6-keto-delta 7 sterols from the marine sponge Oscarella lobularis

Five novel sterols isolated from the marine sponge Oscarella lobularis have been identified on the basis of spectral arguments: cholest-7-ene-3beta,5alpha-diol-6-one (1), cholesta-7,22E-diene-3beta, 5alpha-diol-6-one (2), 24-methylcholesta-7,22E-diene-3beta,5alpha-diol-6-one (3), 24-methylcholesta-7,24(28)-diene-3beta,5alpha-diol-6-one (4), and 24-ethylcholest-7-ene-3beta,5alpha-diol-6-one (5).

A6--a new 45RO monoclonal antibody for immunostaining of paraffin-embedded tissues

The authors report on the extensive characterization, on normal and pathologic tissues, of the T-cell-specific monoclonal antibody (MoAb) A6, which the authors previously found to identify a fixation- and paraffin-embedding-resistant epitope. A6 reacted with most T lymphocytes, macrophages, and Langerhans' cells of normal tissues and with peripheral T-cell lymphomas (31 of 34), Ki-1+ lymphomas (12 of 18), and T-cell leukemias (1 of 5). All cases of X and non-X histiocytosis examined and monocytic leukemias with mature phenotype only were A6 positive. Three of 47 cases of B-cell lymphoma and leukemia were labeled. Hairy cell leukemias, multiple myelomas, and Hodgkin's and Reed-Sternberg cells were negative. The A6 reactivity was preserved with different fixatives (formalin, Bouin's fluid, Carnoy's fixative, and B5) and decalcification procedures and was slightly enhanced by trypsin digestion. The pattern of reactivity of A6 was similar to that obtained with MoAb UCHL-1, recognizing the CD45RO determinant of leukocyte common antigen; however, in pathologic tissues, A6 labeled a higher percentage of cells than UCHL-1. Cross-blocking and enzyme digestion studies (Pronase E [Sigma Chemical, St. Louis, MO] and neuraminidase [Sigma Chemical]) indicated that the two MoAbs may identify close epitopes on the same molecule. In conclusion, the authors' study indicates that A6 is an excellent reagent for detection of the CD45RO molecule on paraffin-embedded normal and pathologic tissues.

Two- and three-color immunofluorescence using aminocoumarin, fluorescein, and phycoerythrin-labelled antibodies and single laser flow cytometry

Antibodies coupled to 7-aminocoumarin (AMCA) emit a bright blue fluorescence under ultraviolet (UV) excitation and are therefore ideal for three-color immunofluorescence (IF) with fluorescein (FITC) and phycoerythrin (PE) labeled reagents; however, due to the different absorption spectra, the use of these fluorophores for multicolor flow-cytometric analysis requires a double light excitation source (e.g., two-laser system). We report a strategy which uses a single argon-ion laser to simultaneously excite AMCA, FITC, and PE, thus allowing the flow cytometric analysis of three immunological parameters. When the UV-visible argon-ion laser is fitted with an appropriate set of mirrors, the 35.1-363.8 nm (UV) and 488 nm wavelengths (accounting for 80 mW and 520 mW, respectively) are simultaneously generated; these lines can then be exactly focused on the same observation point by an achromatic cylindrical lens. A number of comparative analysis were performed with this instrumental set up to verify the sensitivity of AMCA IF and its possible application for multicolor immunophenotypic evaluation of blood cell subsets. When AMCA- and FITC-labeled antimouse Ig antibodies were assessed for their ability to detect limiting amounts of mouse monoclonal antibody bound to cells, the former was less sensitive than the latter. A number of factors, including differences in excitation energy (80 mW for AMCA and 520 mw for FITC) and extinction coefficients (1.9 x 10(4) for AMCA and 6 x 10(4) for FITC) could explain this result.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of differentiation and adhesion molecules in sporadic Burkitt's lymphoma

The phenotypic features of 44 cases of sporadic Burkitt's lymphoma (BL) were investigated by monoclonal antibodies (MoAbs). The majority of cases were positive for HLA-DR (97 per cent), CD19 (100 per cent), CD20 (92 per cent) and CD37 (83 per cent) pan-B markers, in accordance with the B-cell derivation of the tumour; the B-cell restricted markers CD21, CD22 and FMC7 reacted with 28 per cent, 66 per cent and 75 per cent of cases, respectively. Of the mantle zone B-cell specific MoAbs, CD1c was always negative, whereas CD23 and 2.7 were positive with one and two cases, respectively. CD39 was weakly reactive on two specimens, one of which was CD23+. The germinal centre specific MoAbs CD10 and CD77 (Burkitt's lymphoma antigen) displayed a heterogeneous pattern of reactivity and allowed to identify 4 subgroups: CD10+/CD77+ (44 per cent), CD10+/CD77- (15 per cent), CD10-/CD77+ (36 per cent) and CD10-/CD77- (5 per cent). Of 15 cases tested for the expression of CD11a and CD18 lymphocyte-function-associated (LFA-1) antigens and their ligand ICAM-1 (CD54), seven were positive and six negative for the three markers, while the other two cases expressed alternatively the two molecules. Analysis of the putative normal BL cell counterpart, identified with the CD77 marker in normal lymphoid tissues, showed that all CD77+ B-cells were constitutively CD11a+/CD18+, suggesting that BLs are likely to arise from a LFA-1 positive B-cell and may down-regulate these molecules during neoplastic transformation.

[Lymphocyte subpopulations and the soluble interleukin-2 receptor in Hashimoto's thyroiditis and subacute thyroiditis]

There are no univocal experimental data in literature about T cell clone alterations in the peripheral blood during Hashimoto's thyroiditis (TH), autoimmune disease, and during subacute thyroiditis (TSA), an inflammatory thyroid lesion with possibility of "self-perpetuation". The object of our research was to examine the T cell clones, soluble fraction of interleukin 2 receptor and HLA-DR modifications in patients with TH and TSA compared with healthy population. Our results show significant increase of sIL-2r in the TSA compared with normal subjects and with patients TH, where on the contrary, a constant increase of HLA-DR was observed.