Cellular Variant Research Articles

Detection of the ETV6-NTRK3 Chimeric RNA of Infantile Fibrosarcoma/Cellular Congenital Mesoblastic Nephroma in Paraffin-Embedded Tissue: Application to Challenging Pediatric Renal Stromal Tumors

We report the development of a reverse transcriptase polymerase chain reaction assay that reliably detects the ETV6-NTRK3 chimeric RNA characteristic of infantile fibrosarcoma and the cellular variant of congenital mesoblastic nephroma (CMN) in formalin-fixed, paraffin-embedded tissue blocks. The 188 base pair polymerase chain reaction fusion product was detected in 11 of 12 cases of cellular CMN from which a larger sized control RNA band could be amplified, and even in 7 of 8 cases in which the control band was not detectable. A variety of other tumors that are in the histologic differential diagnosis of cellular CMN yielded negative results, including four classic CMNs, four rhabdoid tumors of the kidney, and four clear cell sarcomas of the kidney, confirming the assay's specificity. We further demonstrate the assay's utility by illustrating two cases of molecularly confirmed cellular CMN that mimicked rhabdoid tumor and clear cell sarcoma of the kidney. In contrast to previous reports, five mixed CMNs that had both classic and cellular areas all lacked the ETV6-NTRK3 fusion transcript. These results suggest that cases morphologically defined as mixed CMN may represent a mixed group of genetically distinct entities.

Proliferative activity and tumor angiogenesis is closely correlated to stromal cellularity of fibroadenoma: proposal fibroadenoma, cellular variant.

Fibroadenoma (FA) is the most common benign tumor of the breast in adult women. Some FA have a highly cellular stroma, making it difficult to differentiate from phyllodes tumors (PT). Forty-three FA were grouped into: (i) 27 conventional type (FACT) median stromal cellularity (SC) of highest cellular area (HCA), < or = 125 cells/1 high-power field (HPF); and (ii) 16 cellular variant (FACV) median SC of HCA, > 125 cells/1 HPF. These were studied for the proliferative activity of their stromal cells. Expression of c-fos, p53, basic fibroblast growth factor (bFGF), fibroblast growth factor receptor (FGFR), and vascular endothelial growth factor (VEGF) in the stromal cells were examined in the FA and 12 PT to determine whether it is possible to separate FACV from FACT. The proliferative activity of stromal cells was evaluated by the labeling index (LI) of proliferating cell nuclear antigen (PCNA). Conventional type fibroadenoma stromal cells had the lowest frequency of c-fos, p53, bFGF, FGFR and VEGF protein expression; PT stromal cells had the highest frequency of expression; and FACV stromal cells had an intermediate frequency of expression. Multivariate analysis demonstrated that bFGF and FGFR expression are significantly correlated with SC of FA. Separation of FACV from FACT by SC seems appropriate in revealing the phenotypic and biological differences of FA. The SC of FA seems to be regulated by bFGF and FGFR expression.

Treatment of primary focal segmental glomerulosclerosis.

children. After serial section analysis, the difference Introduction was greater, with a figure of 48.0±6.6% in adults, contrasting with 23.2±7.4% in children, in whom focal Focal segmental glomerulosclerosis (FSGS) is just one lesions were smaller, more segmental and peripheral. of several deceptive denominations for a glomerulopaSuch findings might indicate that FSGS is not exactly thy that in fact is a podocyte disease [1]. A host of the same condition according to age, which might conditions are liable to injure the glomerular epithelial explain differences in response to treatment. cells and lead to FSGS [2]. Therefore, it should be The clinical picture of FSGS comprises two forms stressed that FSGS is a lesion, not a disease. From that apparently correspond to different entities. The this standpoint, the topic ‘Treatment of FSGS’ may first is characterized by insidious onset of low-grade be considered a misnomer, as the podocyte disease proteinuria not reaching nephrotic levels. In a series that is the initial event in the natural history of FSGS of 492 adult cases, Korbet et al. [7] identified 32% of is rarely, if ever, accessible to specific treatment. Once cases with this presenting feature of FSGS. The develthis initial cellular insult has led to the focal and opment of this form is slow and, in our experience, segmental glomerular lesions, the goal of treatment proceeds for decades before it leads to ESRF. The is essentially to control proteinuria and hopefully to second form, which represents two-thirds of cases, is arrest or slow the development of glomerular fibrosis marked by a rapid or even sudden onset of a fullin order to limit progression to end-stage renal failure blown picture of nephrotic syndrome. Initial renal (ESRF). biopsy usually finds lesions of FSGS, but the glomeruli Here we shall distinguish non-nephrotic from may be normal by light microscopy and immunofluonephrotic primary FSGS, focusing mainly on the latter. rescence, leading to the misdiagnosis of minimal change disease. Resistance to corticosteroid therapy should FSGS: description and natural history suggest performing a repeat renal biopsy after completing an adequate course of treatment. In most cases, repeat biopsy discloses transition from minimal The pathological description of FSGS has evolved over changes to FSGS [8], an ominous finding concerning the years. Conventional descriptions refer to lesions further prognosis, as indicated below. Conversely, in initially localized within segments of the glomerular some rapidly developing forms of nephrotic FSGS, tuft lobules. Pathological variants include hilar, perisevere cellular lesions of collapsing glomerulopathy are pheral and glomerular tip lesions [3], and some pubfound in most but not all glomeruli. It has been shown lications contend that some of these localizations entail recently that in these cellular variants of FSGS, podobetter prognosis than others, which has not been cytes undergo a process of cell transdifferentiation, confirmed [4]. Recent histological techniques of threelosing their normal phenotype and expressing macrodimensional (3-D) glomerular reconstruction have shed phagic markers [9]. new light on the concept of ‘focal’ and ‘segmental’ Treatment of non-nephrotic FSGS is not codified. sclerosis. Fuiano et al. [5] have shown by 3-D reconThe absence of nephrotic syndrome and slow developstruction that the glomerular lesions of FSGS are more ment, in addition to ignorance of pathophysiology, widely distributed in the glomerular tufts than determight explain this lack of information in the medical mined by conventional 2-D microscopy, and proposed literature. However, non-nephrotic FSGS certainly to change the term ‘FSGS’ to ‘DSGS, diffuse segmental glomerulosclerosis’. Using the same approach, Fogo excludes an aggressive therapeutic approach based et al. [6 ] found that on initial section, the percentage on corticosteroids or any form of immunosuppressive of sclerosis was 31.5±6.8% in adults vs 11.7±5.7% in regimen. Conservative treatment should consist of dietary measures aimed at reducing overweight, controlling hyperlipidaemia, when present, and normalizing blood Correspondence and offprint requests to: Alain Meyrier, Service de pressure with angiotensin-converting enzyme (ACE) Nephrologie and INSERM U 430, Hopital Broussais, 96 Rue Didot, 75674 Paris Cedex 14, France. inhibitors. Whether AT1 antagonists are endowed with

Surface-expressed invariant chain (CD74) is required for internalization of human leucocyte antigen-DR molecules to early endosomal compartments.

Transport of major histocompatibility complex (MHC) class II molecules to the endocytic route is directed by the associated invariant chain (Ii). In the endocytic pathway, Ii is proteolytically cleaved and, upon removal of residual Ii fragments, class II alpha beta dimers are charged with antigenic peptide and recognized by CD4+ T cells. Although distinct peptide-loading compartments such as MIIC (MHC class II loading compartment) and CIIV (MHC class II vesicles) have been characterized in different cells, there is growing evidence of a multitude of subcellular compartments in which antigenic peptide loading takes place. We employed a physiological cellular system in which surface Ii (CD74) and surface human leucocyte antigen (HLA)-DR were induced either alone or in combination. This was achieved by transient exposure of HT-29 cells to recombinant interferon-gamma (rIFN-gamma). Using distinct cellular variants, we showed that: (i) the majority of Ii molecules physically associate on the cell membrane with class II dimers to form DR alpha beta:Ii complexes; (ii) the presence of surface Ii is a prerequisite for the rapid uptake of HLA-DR-specific monoclonal antibodies into early endosomes because only the surface DR+/Ii+ phenotype, and not the DR+/Ii- variant, efficiently internalizes; and (iii) the HLA-DR:Ii complexes are targeted to early endosomes, as indicated by co-localization with the GTPase, Rab5, and endocytosed bovine serum albumin. Internalization of HLA-DR:Ii complexes, accommodation of peptides by DR alphabeta heterodimers in early endosomes and recycling to the cell surface may be a mechanism used to increase the peptide repertoire that antigen-presenting cells display to MHC class II-restricted T cells.

Dermatofibrome

Dermatofibroma is a common benign fibrohistiocytic lesion which presents with a wide variety of clinicopathologic variants. This may cause great difficulties in delineation from a variety of benign and malignant tumours. According to their peculiarities we differentiate: 1. Dermatofibromas with architectural peculiarities like deep penetrating, atrophic, giant, aneurysmal ("angiomatoid"), haemangiopericytoma-like, palisading or ossifying variants. 2. Dermatofibromas with cellular/stromal peculiarities like clear cell, granular cell, myofibroblastic, sclerotic, monster cell, atypical ("pseudosarcomatous"), elusive ("haemosiderotic"), cholesterotic, and myxoid variants. 3. Dermatofibromas with architectural and cellular/stromal peculiarities in homogenous arrangement like epithelioid cell, cellular benign variants, with smooth muscle proliferation, basal cell carcinoma-like, pseudolymphomatous, multinucleate cell angiohistiocytoma, cellular neurothekeoma, plexiform fibrohistiocytic tumour, plexiform xanthoma and plexiform xanthomatous tumour. 4. Complex or composite dermatofibromas with two or more architectural and cellular/stromal peculiarities in inhomogenous arrangement, e.g. silhouette of an epithelioid cell histiocytoma with plexiform fascicles of cellular neurothekeoma and granular cell features.

Interferon- α inhibits the emergence of cellular stress response-dependent morbillivirus large plaque variants

Cellular levels of heat shock proteins (HSPs) are elevated in response to physiologic states accompanying acute virus infection (e.g. fever). The objective of the present work was to define the antiviral effect of purified human lymphoblastoid IFN in the presence of HSP over-expression. For this purpose, canine distemper virus (CDV) was used since the response of CDV transcription and persistent infection phenotype to elevated HSP is characterized. First, the effect of elevated HSP on CDV lytic infection phenotype in Vero and CV1 cells was defined, and results extended to the closely related measles virus (MV). Cells expressing elevated levels of the major inducible 70-kDa HSP (hsp72) supported the emergence of large plaque variants of both CDV and MV from small plaque purified inocula. IFN treatment concurrent with infection caused a dosage-dependent reduction in the expression of large plaque variants without affecting hsp72 levels or total plaque number. In contrast to the stress response-induced large plaque variant, small plaques were resistant to the antiviral effects of IFN. These data demonstrate the ability of IFN to selectively abrogate the pro-viral effects of HSP over-expression, inhibiting the formation of a plaque phenotype that is correlated to enhanced virulence in animal models of morbillivirus encephalitis.

Clinical predictors of nasal secretory cell quantities in allergy clinic patients.

Nasal cytograms are useful in evaluating patients with inflammatory disease of the nose and paranasal sinuses. When mucosal samples are taken with curette and brush devices, significant numbers of non-leukocytic cells can also be analyzed. To examine two specific morphologic variations in granule-containing epithelial cells in nasal samples obtained from allergy clinic patients and describe their clinical associations. These two cellular variants consisted of goblet cells, with coalesced granules usually displacing the nucleus, and discrete granular mucinous cells (DGMC), which show more discrete granules not displacing the nucleus. Patients from an adult allergy clinic were studied prospectively for nasal mucosal cytology, historical clinical data, nasal physical findings, serum IgE levels, and aeroallergen-specific IgE. Proportions and absolute numbers of goblet cells and DGMC in the nasal mucosal samples were related to other data using simple and multivariate analyses. Both goblet cells and DGMC showed absolute number increases in patients with observable nasal secretions. Discrete granular mucinous cell decreases were also observed in patients with IgE levels greater than or equal to 200 IU/mL and in asthmatic patients. In non-asthmatic patients with nasal eosinophilia, a significantly greater proportion of DGMC was observed compared with other patients (19.8 +/- 11.9% versus 8.5 +/- 5.9%, P = .007), while asthmatics with nasal eosinophilia had mean DGMC quantities closer to that observed in patients without nasal eosinophilia. Increases in goblet cell numbers were observed in patients with specific IgE to aeroallergens compared with other patients (46.5 +/- 46.7 versus 27.0 +/- 23.9, P = .014). Multivariate analysis confirmed that (1) the presence of aeroallergen-specific IgE and (2) the presence of nasal eosinophilia in the absence of asthma were differentially associated with increases in goblet cells and DGMC, respectively. Increases in nasal DGMC and goblet cells differentially relate to specific clinical patterns of nasal cellular inflammation and aeroallergen hypersensitivity. The nasal epithelial cell profile associated with nasal eosinophilia in asthmatics may differ from that observed in non-asthmatic nasal eosinophilia.

Complementation Cloning of NEMO, a Component of the IκB Kinase Complex Essential for NF-κB Activation

We have characterized a flat cellular variant of HTLV-1 Tax-transformed rat fibroblasts, 5R, which is unresponsive to all tested NF-κB activating stimuli, and we report here its genetic complementation. The recovered full-length cDNA encodes a 48 kDa protein, NEMO ( N F-κB E ssential MO dulator), which contains a putative leucine zipper motif. This protein is absent from 5R cells, is part of the high molecular weight IκB kinase complex, and is required for its formation. In vitro, NEMO can homodimerize and directly interacts with IKK-2. The NEMO cDNA was also able to complement another NF-κB–unresponsive cell line, 1.3E2, in which the protein is also absent, allowing us to demonstrate that this factor is required not only for Tax but also for LPS, PMA, and IL-1 stimulation of NF-κB activity.

RT-PCR investigation of fibronectin mRNA isoforms in malignant, normal and reactive oral mucosa.

This study aimed to establish patterns of cellular fibronectin mRNA splice variants in normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, and focal reactive overgrowths of oral mucosa. Particular emphasis was placed on evaluation of either the EDA or EDB domains as markers of malignancy. Total RNA was extracted from normal oral mucosa, oral squamous cell carcinoma, oral leukoplakias with and without atypia, reactive epulides, fibroepithelial polyps and denture-related hyperplasia. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify different fibronectin transcripts at three splice sites (EDA, EDB and IIICS). All the tissues investigated produced EDA+, EDA-, EDB+ and EDB- splice variants, and this study did not support RT-PCR-based detection of either EDA or EDB domains as markers of malignancy in oral tissues. Variations in IIICS splice patterns were observed, although these were not specific to any lesion group. In particular, there were differences in either the inclusion or omission of the domain coding for the CS-5 binding site for alpha 4 beta 1 integrin, whereas the CS-1 binding site for alpha 4 beta 1 integrin was typically present when additional domains were included at the IIICS splice site. In conclusion, complex patterns of fibronectin splice variant transcripts exist in normal and pathological oral mucosa. This may reflect the multiple biological functions identified for fibronectin proteins, although the significance of different specific fibronectin splice variants has yet to be fully elucidated.

Mammary fibroadenoma and some phyllodes tumour stroma are composed of CD34+ fibroblasts and factor XIIIa+ dendrophages.

Fibroadenomas and mammary phyllodes tumour arise by proliferation of mammary stroma and epithelial elements. However, it is the stromal element that determines the biology of these biphasic tumours. Normal mammary stroma, like most collagenous connective tissue, contains resident populations of CD34+ dendritic interstitial cells and scattered factor XIIIa+ collagen-associated dendrophages. Actin+myofibroblasts are usually absent from mammary stroma in non-disease states. To determine whether CD34+ and factor XIIIa+ cells proliferate in fibroadenomas and phyllodes tumours, and to study myofibroblastic differentiation in these lesions, we examined 19 fibroadenomas in 14 patients along with five low grade and two high grade phyllodes tumours. We employed antibodies against the human progenitor cell antigen CD34, coagulation factor XIIIa and HHF-35 actin. In three fibroadenomas and two phyllodes tumours, we used Ki-67 antigen to study cell proliferation and oestrogen and progesterone receptors to study possible hormonal influence on stromal cells. In all fibroadenomas, CD34 strongly stained interlobular, pericanalicular and intracanalicular fibroblasts with collagenous and/or myxoid features. Four low grade phyllodes tumours also had CD34+ fibroblasts as did one high grade tumour. Actin reactivity varied and was most pronounced in six fibroadenomas resembling the so-called cellular variant, while seven regular fibroadenomas had no actin+stromal cells and six had only focal and weak actin+stromal cells. Factor XIIIa+ cells were prominently admixed in the stroma of all tumours studied comprising from 5% to 20% in fibroadenomas and, focally, up to 50% in phyllodes tumours. Oestrogen and progesterone receptors were expressed only in glandular elements. Ki-67 index in stromal cells was 1% to 3% in fibroadenoma, 10% to 20% in low grade, and 20% to 40% in high grade phyllodes tumour. We conclude that fibroadenomas and some phyllodes tumours are composed of CD34+ fibroblasts that show varying myxoid, collagenous or myofibroblastic differentiation. The fibroblasts are accompanied by a subset of dendritic histiocytes that express factor XIIIa. Fibroadenoma variants show prominent collagenous actin+myofibroblastic differentiation of CD34+ stromal cells, sometimes with a gradient of CD34 down-regulation. Fine-needle or limited stereotactic core biopsy of these biphasic tumours, if they yield only stromal cells, must be distinguished from other CD34+ stromal tumours. Increased factor XIIIa+ dendrophage populations were seen in phyllodes tumours, especially in two high grade tumours that had malignant fibrous histiocytoma-like features, suggesting clonal evolution toward the fibrohistiocytic final pathway. Further study of CD34 and factor XIIIa+ mammary stromal cells in larger numbers of phyllodes tumours might ascertain whether increasing factor XIIIa reactivity correlates with differentiation and increased tumour aggressiveness.

Presence or absence of trisomy 11 is correlated with histologic subtype in congenital mesoblastic nephroma

Fluorescence in situ hybridization utilizing a probe for the alpha satellite repeat sequence on chromosome 11 was used to detect variations in the number of chromosomes 11 in 24 formalin-fixed, paraffin-embedded congenital mesoblastic nephromas. Evidence of trisomy 11 was found in nearly half of the tumors. More importantly, the presence of trisomy 11 was associated with the cellular histologic variant of this tumor.

Nerve sheath myxoma (neurothekeoma) of the skin: light microscopic and immunohistochemical reappraisal of the cellular variant*

Nerve sheath myxoma (NSM) is a rare cutaneous neoplasm, the histogenesis of which is controversial. Fifteen cases of NSM were studied by routine light microscopy and with a broad panel of immunohistochemical stains. NSM were classified into three groups based on cellularity, mucin content and growth pattern. 1) The hypocellular (myxoid) type (5/15 cases) showed frequent encapsulation or sharp circumscription. Immunohistochemically this type was strongly positive for S-100 protein and collagen type IV and variably positive for epithelial membrane antigen. 2) The cellular type (4/15 cases) had scant mucin and ill-defined nodular or infiltrating growth. Immunostaining showed positive reaction for neuron specific enolase (2/4), Leu-7 (1/4) and smooth muscle specific actin (2/4), and was negative with the other antibodies. 3) The "mixed type" (6/15 cases) had variable cellularity and mucin content with poor demarcation and variable immunolabeling. We conclude that: 1) there are major light microscopic and immunohistochemical differences between the classical hypocellular (myxoid) and the cellular forms of NSM (neurothekeoma); 2) while the immunohistochemical results support the presence of nerve sheath differentiation in the classical forms of NSM, and to some extent in the mixed forms, there is an absence of convincing evidence of neural differentiation in the cellular variant by either light microscopy or immunohistochemistry; 3) the variable immunophenotypes suggest that differentiation other than neural may take place in CNT.

The Neuroendocrine Cell Population of the Human Prostate Gland

Neuroendocrine cells have been reported in up to 50% of all prostatic adenocarcinomas. These cells appear to influence the prognosis of these tumors. The distribution of the neuroendocrine cell population in the normal prostate gland, through all stages of development, has not been documented previously. We define the distribution of this cell population and describe 4 cellular morphological variants. The neuroendocrine cells of the peripheral zone appear to respond to factors present at birth and at puberty, while those of the periurethral glands and prostatic duct system are not influenced by this factor. It is postulated that this factor may be the levels of circulating androgens. The presence of at least 2 functionally distinct populations of neuroendocrine cells raises the possibility of 2 different embryonic origins. The study documents the distribution of calcitonin-producing cells but fails to detect the presence of somatostatin.

Gene amplification and gene deletion are induced at different rates in V79/AP4 Chinese hamster cells.

The effect of mitomycin C (MMC) treatment on gene amplification and gene deletion induction in a V79/AP4 Chinese hamster cell line was investigated. Spontaneous and induced cellular variants resistant to N-phosphonacetyl-L-aspartate (PALA), which selects for carbamyl-P-synthetase, aspartate transcarbamylase and dihydroorotase (CAD) gene amplification events, and to intermediate concentrations of 2,6-diaminopurine (DAP), which selects for adenine phosphoribosyl transferase (aprt) gene deletion events, were isolated. The molecular analysis of spontaneous and induced PALA- and DAP-resistant clones showed that while in the former the CAD gene was amplified, in the latter both mutations and deletions occurred at the aprt gene. These results indicate that MMC favored the rise of gene amplification rather than gene deletion events, and suggest that aberrant DNA replication processes were responsible for the observed gene amplification.

FcR may function as a progression factor of nonlymphoid tumors.

Tumor progression is a multistep process involving genetic and epigenetic changes in a transformed clone. Some of these changes may be induced by host factors which may also select for transformed cellular variants with a high ability to survive and propagate. In this article we review studies showing that receptors for the Fc portion of IgG may be expressed on cells from human or animal tumors of nonlymphoid origin. We also review data demonstrating that at least with respect to cells transformed in vitro with Polyoma virus, transformation per se is not sufficient for the induction of Fc receptor expression. We also summarize preliminary data showing that Fc receptor expression is causally involved in conferring a high malignancy phenotype upon transformed cells. Possible mechanisms to explain these observations are discussed.

A genetic element that increases the frequency of gene amplification.

A repetitive mammalian genetic element, HSAG-1, has been shown to promote the amplification of the vector, pSV2-DHFR, containing the functional cDNA for dihydrofolate reductase (DHFR). LR-73 cells, a line of Chinese hamster ovary cells, were transfected with this recombinant construct or with the parent vector, then subjected to culture in selective medium containing steadily increasing concentrations of methotrexate, a drug which specifically inhibits DHFR. Cultures transfected with the HSAG-1-containing construct acquired drug resistance faster than those transfected with the parent vector. This acceleration of acquisition of drug resistance was due to an increased probability of the generation and subsequent selection of cellular variants with increased copy numbers of the vector. The effect has also been observed in CHO(DHFR-) and HeLa cell lines. Possible mechanisms for the effect of the HSAG-1 element on gene amplification are discussed.

The CD45 protein tyrosine phosphatase is required for the completion of the activation program leading to lymphokine production in the Jurkat human T cell line

Stimulation of the T cell antigen receptor, TCR-CD3, induces tyrosine phosphorylation of specific cellular proteins through activation of a tyrosine kinase. The possible regulatory role of the CD45 protein tyrosine phosphatase in this process was explored by studying the functional properties of cellular variants of the Jurkat T cell line which have been selected to have normal levels of the TCR-CD3 complex, but low or negative expression of CD45. These variants had less than 20% of the normal membrane tyrosine phosphatase activity. Triggering the TCR-CD3 receptor on the CD45 variants with anti-CD3 mAb induced the activation of a tyrosine kinase. Tyrosine phosphorylation of cellular substrates as well as of the CD3 zeta chain was qualitatively comparable to normal cells although the extent of stimulation was lower. No differences were observed between the variants and the normal cells in the duration of the tyrosine phosphorylation signal. The increase in intracellular calcium concentration following receptor stimulation was also less efficient, suggesting that CD45 is necessary for optimal generation of the second messengers of the activation. The CD45 deficient cells secreted highly reduced levels of lymphokines (IL-2, IL-3 or GM-CSF) after activation by anti-CD3 mAb combined with the phorbol ester TPA. This impaired lymphokines production is related to the absence of CD45 since a CD45+ revertant subclone, isolated from one CD45- clone, produced normal levels of cytokines upon activation via CD3, while CD45- subclones were unable to secrete cytokines following activation via CD3. However, upon activation with Ca2+ ionophore and PMA, all CD45- (sub)clones secreted cytokines at levels comparable to those produced by CD45+ cells. These results show that CD45 is required for cytokine production after activation via the TCR-CD3 complex.

Correlation between leukocyte-associated plasma proteins and white cell differential count

Prealbumin, albumin, orosomucoid (including the cellular variant orosomucoid2), alpha 1-antitrypsin, haptoglobin and transferrin were quantified in 107 cell samples from acute and chronic myeloid leukaemia, seven polycytaemia, seven normal blood marrow and 56 normal blood leukocytes by crossed immunoelectrophoresis. By statistical multivariate analyses, the individual plasma proteins and their combined protein patterns were correlated with the diagnoses and it was demonstrated that acute leukaemia cell samples contained significantly different protein patterns compared with the other diagnostic groups and normal controls. By comparison with the white blood cell differential count, in 78 samples of acute leukaemia, it was demonstrated that the protein patterns were significantly correlated with the specific cell types in the samples. In all, the differential counts accounted for about 29% of the variation in protein patterns. Alpha 1-antitrypsin was found significantly correlated with the myeloblasts and myelo-band cells. Orosomucoid2 and haptoglobin were significantly correlated with mature granulocytes and albumin was significantly correlated with lymphocytes. In some cell samples, after cytotoxic treatment of acute leukaemia, the granulocytes did not have orosomucoid2 despite normal morphology, suggesting defective maturation of these granulocytes. These results indicate that the mechanisms responsible for uptake of plasma proteins are highly specific for different cell types and in the case of myeloid cells specifically related to cell differentiation.

Inhibition by AZT of HIV-1 Replication in Acutely Infected U-937 Cells

We studied the effect of AZT on the replication of HIV-1 in freshly and chronically infected U-937 monocytoid cells over a period of 2 months. Expression of viral antigens was monitored by indirect immunofluorescence, and viral replication was assessed by reverse transcriptase assay on virus pelleted from culture fluids. In U-937 cells not treated by AZT, viral antigens were expressed by 7 days after infection. The inclusion of a variety of concentrations of AZT in the culture medium was shown to retard virus replication in a dose-dependent fashion, although a complete inhibitory effect was not seen with any clinically attainable concentration of drug. Exposure of HIV-1-inoculated cells to AZT did not give rise to progeny virus possessing a drug-resistant phenotype. However, the study of clonal derivatives of U-937 cells revealed cellular variants with increased susceptibility to HIV-1, and against which AZT had reduced effectiveness in comparison with the parental line. No effect of AZT was seen on cells already infected by HIV-1, suggesting that this drug had no influence on viral replication in U-937 cells into which viral DNA had previously integrated.

Classical and cellular (atypical) congenital mesoblastic nephroma: A clinicopathologic, ultrastructural, immunohistochemical, and flow cytometric study

Sixteen cases of congenital mesoblastic nephroma (CMN) were studied. The tumors showed variable patterns of growth, degrees of cellularity, and mitotic activity. Six tumors had the classical pattern of CMN, seven were of the cellular or atypical variant and three showed combined features. The mean ages at presentation were 16 days, 5.3 months, and 2.3 months, respectively. Average size and weight were 5.1 cm and 94 g for classical CMN, 9.1 cm and 620 g for cellular CMN and 10.5 cm and 150 g for combined tumors. Cyst formation, hemorrhage and necrosis were confined to cellular CMNs and to cellular areas of combined CMNs. Mitotic activity ranged from 0 to 1 10 high-power fields (HPFs) in classical tumors to 25 to 30 10 HPFs in cellular tumors. Clear cell sarcoma-like areas were observed in three neoplasms. In ten cases there was invasion of perirental fat; in one case each, invasion of the psoas muscle, renal vein wall, and renal vein lumen was observed. Ultrastructural and immunohistochemical studies showed features consistent with myofibroblastic differentiation. Flow cytometric analysis revealed euploidy in one classic CMN, one cellular CMN and in classic areas of a combined CMN; cellular areas of the latter tumor were aneuploid. All patients with follow-up were alive without evidence of disease after a mean period of 5 years following nephrectomy alone. No correlation was observed between the pathologic features assessed and the biologic behavior of these neoplasms.