α1-Antitrypsin, Transferrin, Alkaline Phosphatase, Phosphohexoseisomerase and γ-Glutamyltransferase in Breast Cyst Fluid

The levels of α1-antitrypsin, transferrin, alkaline phosphatase, phosphohexoseisomerase and γ-glutamyltransferase were measured in 32 samples of breast cyst fluid, and a wide range of values was obtained. The levels observed in some samples for these parameters, being similar to those of normal serum, might suggest a mechanism of plasma exudation for the formation of breast cyst fluid. Nevertheless, a comparison with the maximum normal serum reference value revealed very high levels of γ-glutamyltransferase in all of the samples; about 50% also exhibited high levels of phosphohexoseisomerase. These results indicate that the formation of breast cyst fluid takes place with a specific local production, in addition to the mechanism of selective plasma exudation. Moreover, elevated transferrin levels in some cyst fluids are probably the expression of a high biosynthetic activity and could be diagnostically useful in the course of breast gross cystic disease. The importance of these observations from the point of view of diagnostic and prognostic trends are discussed.

Circulating Immune Complexes in Human Breast Cyst Fluids: Relationship with Intracystic Immunoglobulin and Electrolyte Levels

Circulating immune complexes, the major classes of immunoglobulins and electrolyte concentrations were measured in sixty-two breast cyst fluids aspirated in women affected by gross cystic breast disease. Two main classes of cysts were defined according to the Na/K ratio. Appreciable levels of immunoglobulins were found in almost all samples examined; 66% of breast cyst fluids showed increased levels of immune complexes. A highly significant linear correlation between increased values of immune complexes and immunoglobulin M (p < 0.001) was found in apocrine cysts, characterized by Na/K ratio <3. However, a significant inverse linear correlation was found between positive values of immune complexes and lowered levels of immunoglobulins A (p < 0.001) and G (p < 0.001) in epithelial cysts with Na/K ratio > 3. These data suggest and confirm that the menstrual cycle can also influence or modulate the metabolic activity of human breast cells as a part of the secretory immune system. The relationship between immune complexes and immunoglobulins and electrolyte profiles may provide further knowledge about the immunological features of breast cyst fluid and suggest the possible alteration of immune-response in cystic breast lesions associated with increased cancer risk

Glycosaminoglycan sulodexide modulates inflammatory pathways in chronic venous disease

Inflammation represents an important epiphenomenon in the etiopathogenesis of chronic venous disease, a worldwide debilitating condition affecting millions of subjects. The pathophysiology of chronic venous disease (CVD) is based on the hemodynamic abnormalities in conjunction to alterations in cellular and extracellular matrix biocompounds. The endothelial dysfunction results from early perturbation in the endothelium linked to glycocalyx injury and promoted by inflammatory cells and mediators (such as matrix metalloproteinases and interleukins), which lead to progressive dilation of the vein resulting in chronic venous insufficiency. Activated leukocytes during the inflammatory process release enzymes, free radicals, chemokines and inflammatory cytokines in the vessel microenvironment, which are responsible for the changes of the venous wall and venous valve, reflux and venous hypertension, and the development/progression of tissue destruction and skin changes. Sulodexide, a highly purified mixture of glycosaminoglycans composed by 80% fast moving heparin and 20% of dermatan sulphate, exhibits anti-thrombotic and profibrinolytic properties, restoring also the essential endothelial glycocalyx. Glycosaminoglycan sulodexide has been also characterized to reduce the release of inflammatory cytokines/chemokines and to inhibit the matrix metalloproteinases-related proteolytic cascades, counteracting endothelial dysfunctions. The pleiotropic effects of sulodexide set the basis for a very promising agent in treating the spectrum of CVD.

Pathophysiology of chronic venous disease

Chronic venous disease (CVD) is a debilitating condition with a prevalence between 60-70%. The disease pathophysiology is complex and involves genetic susceptibility and environmental factors, with individuals developing visible telengiectasias, reticular veins, and varicose veins. Patient with significant lower extremity symptoms have pain, dermal irritation, swelling, skin changes, and are at risk of developing debilitating venous ulceration. The signature of CVD is an increase in venous pressure referred to as venous hypertension. The various symptoms presenting in CVD and the clinical signs that are observed indicate that there is inflammation, secondary to venous hypertension, and it leads to a number of inflammatory pathways that become activated. The endothelium and glycocalyx via specialized receptors are critical at sensing changes in shear stress, and expression of adhesion molecules allows the activation of leukocytes leading to endothelial attachment, diapedisis, and transmigration into the venous wall/valves resulting in venous wall injury and inflammatory cells in the interstitial tissues. There is a complex of cytokines, chemokines, growth factors, proteases and proteinases, produced by activated leukocytes, that are expressed and unbalanced resulting in an environment of persistent inflammation with the clinical changes that are commonly seen, consisting of varicose veins to more advanced presentations of skin changes and venous ulceration. The structural integrity of protein and the extracellular matrix is altered, enhancing the progressive events of CVD. Work focusing on metabolic changes, miRNA regulation, inflammatory modulation and the glycocalyx will further our knowledge in the pathophysiology of CVD, and provide answers critical to treatment and prevention.

Zymographic analysis and characterization of MMP-2 and -9 forms in human sound dentin

The role and function of dentin matrix metalloproteinases (MMPs) are not well-understood, but they may play a key role in dentinal caries and the degradation of resin-bonded dentin matrices. To test the null hypothesis that MMP-9 is not found in dentin matrix, we used gelatin zymography to extract and isolate all molecular forms of gelatinolytic MMPs in demineralized mature sound dentin powder obtained from extracted human molars, characterizing and identifying the enzymes by Western blotting. Gelatinolytic MMPs were detected in extracts of demineralized dentin matrix and identified as MMP-2 and MMP-9. Acidic extracts (pH 2.3) yielded 3-8 times more MMP activity than did EDTA (pH 7.4). Their activation may contribute to dentin matrix degradation, which occurs during caries progression and following resin bonding. Inhibition of MMP-2 and -9 proteolytic activity may slow caries progression and increase the durability of resin-dentin bonds.

Melatonin reduces early changes in intramitochondrial cardiolipin during apoptosis in U937 cell line

Cardiolipin (CL) is found exclusively in the inner mitochondrial membrane. CL deficiency leads to an alteration in the stability of mitochondrial membranes, to an increased permeability as well as a decreased respiratory rate, and therefore to mitochondria which are completely dysfunctional. It is known that reactive oxygen species (ROS) cause a decrease and a variation in CL content, concomitantly the formation of the mitochondrial permeability transition pore facilitates the release of cytochrome c (cyt c) into the cytosol. Melatonin (Mel), the secretory product of the pineal gland, is a potent and efficient endogenous radical scavenger. It has been shown to protect, various biomolecules, such as DNA, membrane lipids, and cytosolic proteins from oxidative damage. To evaluate the protective role of Mel, we have studied U937 cells treated with UV-B irradiation. In our model, the administration of 1mM Mel before UV-B irradiation showed a significant protection from apoptotic cell death, in particular, mitochondrial structure and function were preserved through apoptotic pathways when cells were preincubated with 1mM Mel before UV-B exposure. The cardiolipin-sensitive probe 10-nonyl acridine orange (NAO) was used to monitor changes in mitochondrial lipids. Our data suggest that the Mel treatment protects CL from ROS and this suggests a possible link with the reduction of the apoptotic phenomenon.

Matrix metalloproteinase inhibitors as anticancer therapeutics

Matrix metalloproteinases (MMPs), also designated as matrixins, play a central role in many biological processes and are involved both in physiologic cellular processes and in pathologic situations such as tumor growth, invasion and metastasis. For more than 30 years MMPs have been considered as promising targets for cancer therapy and a number of different synthetic and natural MMP inhibitors have been identified as cytostatic and anti-angiogenic agents and have begun clinical testing in view of their specific implication in malignant tissues. Although preclinical studies were so compelling to encourage several clinical trials, the past years have seen a consistent number of disappointments and limited success. The critical examination of previous studies shed light on new information about the cellular source, substrates and mode of action of MMPs, focusing the attention of future research on the identification of specific MMP targets in tumors at different stage of tumor progression, both in order to improve efficacy and to reduce the side effect profile. In this review we discuss the current view on the feasibility of MMPs as target for therapeutic intervention in cancer, taking into account that the perspective may be of great value for molecular medicine for the twenty-first century, providing intriguing information about the MMPs as mediators in biology and pathology, and as targets for disease therapies.

Flow cytometric evaluation ofVibrio parahaemolyticus adhesion inhibition to human epithelial cells

BACKGROUND

The present report demonstrates the usefulness of flow cytometry for a quantitative assessment of adhesion inhibition of a Vibrio parahaemolyticus strain to human epithelial cells to acquire more information about the nature of its adhesins.

METHODS

The inhibition of the adhesive process to Hep-2 was assayed by adding several monosaccharides to infected cells monolayers. The quantification of the adherent bacteria, labeled with a specific primary antibody plus a secondary fluorescein isothiocyanate-conjugated antibody, was performed by flow cytometry in comparison with light microscopy. The adherence was quantified in terms of the proportion of cells with adherent V. parahaemolyticus and as the mean of adherent bacteria per cell.

RESULTS

The adhesion showed a percentage of 98% with a mean fluorescence channel of 331 comparable to those obtained by light microscopy. The addition of monosaccharides resulted in a D-mannose and N-acetyl-galactosamine sensitive adherence. Even if this environmental strain also showed a mannose-sensitive cell-associated hemoagglutination that could mediate V. parahaemolyticus adherence, our results suggest that different sites for an irreversible adherence to host cell are involved.

CONCLUSIONS

Flow cytometry in combination with indirect immunofluorescence is an effective tool to investigate the adhesive process of bacteria to epithelial cells because it is more sensitive and reproducible than visual counting of bacteria performed in light microscopy.

Multiple roles of matrix metalloproteinases during apoptosis

Structural, molecular and biochemical approaches have contributed to piecing together the puzzle of how matrix metalloproteinases (MMPs) work and contribute to various disease processes. However, MMPs have many unexpected substrates other than components of the extracellular matrix which profoundly influence cell behaviour, survival and death. With the current understanding of diverse/novel roles of matrix metalloproteinases--particularly their direct or indirect relevance for the early steps during programmed cell death--some seemingly contrasting results seem less surprising. To better target MMPs an appreciation of their many extracellular, intracellular and intranuclear functions, often acting in opposing directions with paradoxical roles in cell death, is carefully required.

Evaluation of leukocyte stabilisation in TransFix®-treated blood samples by flow cytometry and transmission electron microscopy

In this report, we have evaluated the effects of a TransFix-based stabilisation technique on leukocyte scatter characteristics, immunophenotyping, membrane permeability, absolute cell counting and morphology to extend previously reported flow cytometric data focused on the lymphocyte population. We show that scatter characteristics, immunophenotyping and absolute cell counting are well preserved, particularly in the lymphocyte population. Nevertheless, a general increase in membrane permeability, evaluated by propidium iodide (PI) uptake, was observed in TransFix-treated leukocyte subsets. Ultrastructural observations show selective morphological preservation (up to 10 days of storage) of lymphocytes and, to a lesser extent, of monocytes. In contrast, granulocytes have necrosis-like features, although the plasma membrane seems well preserved. Therefore, electron microscopy observations reflect modifications induced in different cell populations as evidenced by flow cytometry (FC). The data indicate that this short-term stabilisation method is particularly suitable for the analysis of human lymphocytes and it is a good procedure for quality control programmes for inter- and intra-laboratory performance evaluation; good results are obtained with respect to antigen definition and absolute cell counting procedures. Any apoptotic pathways in leukocyte subsets are blocked for at least 10 days.

Integrin and cytoskeleton behaviour in human neuroblastoma cells during hyperthermia-related apoptosis

Hyperthermia induces several cellular responses leading to morphological changes, cell detachment and death. Loss of integrins from the cell surface after acute heat-treatment may block several physiological signalling pathways, but whether the assembly network between integrin and cytoskeletal actin is perturbed during hyperthermic treatment is unknown. In this study we tested this hypothesis by evaluating cell morphology, protein cytoskeletal profile and integrin CD11a content in both adherent and floating SK-N-MC human neuroblastoma cells. Morphological and cytometric analyses confirmed that hyperthermia is an effective apoptotic trigger, revealing the typical chromatin margination, cell shape changes and 7-AAD incorporation. After hyperthermia, cytoskeletal proteins showed an increase of high-molecular-weight aggregates and a significant decrease of both actin and CD11a content with respect to control cells. The integrin CD11a and membrane-bound actin alterations found in detached floating neuroblastoma cells recovered after heat-shock may cause the cytoskeletal abnormalities related to the observed surface cell rounding/blebbing and anoikis, early events of hyperthermia-induced programmed cell death.

Tissue inhibitors of metalloproteinases and programmed cell death: conundrums, controversies and potential implications

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases, which can synergistically degrade the major components of extracellular matrix (ECM). A key role in maintaining the balance between ECM deposition and degradation in several physio-pathological processes is carried out, through multiple biological functions, by four members of the tissue inhibitors of metalloproteinases (TIMPs) family. TIMP-1 and TIMP-2 are capable of inhibiting the activities of MMPs, can inhibit tumour growth, invasion and metastasis, exhibit growth factor-like activity, can inhibit angiogenesis and suppress programmed cell death (PCD) independently of the MMP-inhibitory activity. TIMP-3 is the only member which is tightly bound to ECM, inhibits TNF-alpha converting enzyme and induces PCD through the stabilization of TNF-alpha receptors on the cell surface. TIMP-4 plays a role in ECM homeostasis in a tissue-specific fashion and its overexpression induces PCD. The aim of this article is to review the exciting and intriguing literature on TIMPs, with special emphasis on their conflicting-paradoxical roles in PCD and their potential clinical usefulness.

Biochemical properties of metalloproteinases from the hemolymph of the mussel Mytilus galloprovincialis Lam

The expression of matrix metalloproteinases (MMP) with gelatinase activity was found in the whole hemolymph of the marine mussel Mytilus galloprovincialis Lam. Cleavage activity was specific for gelatin; very little activity towards human type-IV collagen, and no activity for cold fish gelatin, casein or bovine serum albumin were detected. EDTA and 1,10-phenanthroline were inhibitory, suggesting that mussel MMPs require divalent cations for their proteolytic activity; in fact, the presence of exogenously added divalent ions significantly protected the MMPs from inhibition. No inhibition was detected with serine or cysteine proteinase inhibitors. The specific vertebrate inhibitors as well as the classical vertebrate activator of MMPs were without effect, whereas sulphydryl reducing agents had a strong inhibitory effect. Mussel MMPs showed an exponential curve of thermal-dependent decay that was not protected by the presence of metal ions. Overall the results indicate both similarities and differences between invertebrate and vertebrate gelatinases, providing information for understanding the biological role of these ancient proteinases.

Prostate-specific antigen (PSA/hK3): a further player in the field of breast cancer diagnostics?

Since its identification, much information has been obtained about prostate-specific antigen (PSA, or human glandular kallikrein 3 [hK3]), a kallikrein-like serine protease that is the most valuable tumour marker for the screening, diagnosis and management of human prostate carcinoma. Recently, it has become widely accepted that PSA is also present in many nonprostatic sources, casting doubts about the specificity of its tissue expression. Here we summarize the findings on the biomolecular expression of PSA in breast secretions, cells and tissues of healthy and diseased females. Although several studies have strongly suggested that the molecular forms of PSA seem to represent a potential tool for the risk assessment of breast cancer, recent reports have yielded conflicting results. Although several studies have suggested new biological function(s) for PSA in breast physiopathology, more studies are needed to enlist PSA unequivocally as an additional weapon in the anticancer armoury in breast cancer diagnostics.

Matrix metalloproteinases expression in HL-60 promyelocytic leukemia cells during apoptosis

Human promyelocytic leukemia HL-60 cells have been used as a model to study both the expression of matrix-metalloproteinases and the mechanisms of programmed cell death. In the present study we examined the expression of these proteases in HL-60 cells stimulated by different apoptotic triggers. As shown by zymography, HL-60 cells released three major isofroms of the matrix-degrading proteases; when the leukemic cells were grown in serum-free conditions, as well as after hyperthermia and methotrexate treatment, we found a significant loss of the constitutive production of the 92 kDa matrixmetalloprotease, with an unequivocable molecular and ultrastructural evidence of programmed cell death. These results suggest that in HL-60 cells the expression/release of matrix metalloproteases can be down-regulated in the presence of the apoptotic-induced alterations, and that the decreased matrix-degrading capacity of this leukemic cell line during apoptosis may reduce its invasive potential.

Prostate-specific antigen synthesis and secretion by human placenta: a physiological kallikrein source during pregnancy

Prostate-specific antigen (PSA), a kallikrein-like serine protease until recently thought to be prostate specific, has been demonstrated in various nonprostatic tissues and body fluids. PSA has been also found in human endometrium and amniotic fluids, even if the significance of this novel expression is unclear. In this study, we have demonstrated by multiple techniques that human placental tissue, obtained at delivery from normal full-term pregnancies, synthesizes and secretes PSA. RT-PCR showed the presence of PSA messenger ribonucleic acid; biochemical, chromatographic, and immunological studies revealed the expression of both free and complexed PSA forms; immunoelectron microscopy indicated the syncytiotrophoblast as the site of PSA synthesis and secretion. Moreover, in vitro experiments demonstrated that PSA production and secretion are up-regulated by 17beta-estradiol, a pregnancy-related steroid hormone. These results suggest that human placenta is a source of the PSA present in amniotic fluid and maternal serum during pregnancy.

Prostate-specific antigen found in type I breast cyst fluids is a secretory product of the apocrine cells lining breast gross cysts

Prostate-specific antigen (PSA), a serine protease thought to be exclusively produced by the prostate epithelial cells, has been recently found in human breast tissues and fluids. PSA in breast cancer is associated with the presence of steroid-hormones and receptors, and its presence seems to be a favourable prognostic indicator. In order to clarify whether the cells lining breast cysts may represent the source of PSA found in human breast cyst fluid, we performed an ultrastructural immunolocalization of PSA in the cells surrounding Type I breast cysts, obtained from breast cyst fluids of women affected by breast gross cystic disease, the most commonly occurring benign breast lesions associated with increased cancer risk. These apocrine cells show morphological features typical of actively synthesizing and secreting cells, and a PSA labelling distributed on free ribosomes, RER cisternae, and secretory granules, indicating that the metabolically active apocrine cells lining the Type I cysts are responsible for the production and secretion of PSA in Type I breast cyst fluids. The synthesis and intracystic accumulation of this serine protease in biosynthetically active apocrine Type I cysts can play an important role in the natural history of breast gross cystic disease as well as in the mechanism of cyst evolution.

The kidney during hibernation and arousal from hibernation. A natural model of organ preservation during cold ischaemia and reperfusion

BACKGROUND

During hibernation the kidney is in a hypothermic condition where renal blood flow is minimal and urine production is much reduced. Periodical arousal from hibernation is associated with kidney reperfusion at increasing body temperature, and restored urine production rate.

METHODS

To assess the degree of structural preservation during such extreme conditions, the kidney cortex was investigated by means of electron microscopy in the dormouse Muscardinus avellanarius during winter hibernation, arousal from hibernation and the summer active period.

RESULTS

Results show that the fine structure of the kidney cortex is well preserved during hibernation. In the renal corpuscle, a sign of slight lesion was the focal presence of oedematous endothelial cells and/or podocytes. Proximal convoluted tubule cells showed fully preserved ultrastructure and polarity, and hypertrophic apical endocytic apparatus. Structural changes were associated with increased plasma electrolytes, creatinine and urea nitrogen, and proteinuria. During the process of arousal the fine structure of the kidney cortex was also well maintained.

CONCLUSION

These results demonstrate that dormice are able to fully preserve kidney cortex structure under extreme conditions resembling e.g. severe ischaemia or hypothermic organ storage for transplantation, and reperfusion. Elucidation of the mechanisms involved in such a natural model of organ preservation could be relevant to human medicine.

Immunoreactivity, ultrastructural localization, and transcript expression of prostate-specific antigen in human neuroblastoma cell lines

Prostate-specific antigen (PSA) is considered a highly specific biochemical marker of the human prostate gland, and it currently is used for prostate cancer diagnosis and monitoring. Recently, PSA production and secretion were found in nondiseased and diseased cells, tissues, and fluids from women. In this study, we characterized the presence of PSA in two human neuroblastoma cell lines with biochemical, ultrastructural, and molecular approaches. Using reverse transcription-PCR, we identified PSA mRNA, and Western blotting revealed a substantial amount of complexed form of PSA protein, which is localized mainly in free ribosomes. Although the role of PSA in human neuroblastoma cell lines is still unknown, our study supports the hypothesis that this serine protease may be involved in controlling the growth of human brain tumor cells, adding more support to the notion that PSA is a widespread kallikrein-like protease with biological functions much more complex than recently thought.

Ultrastructural characterization and biochemical profile of human gross cystic breast disease

Human gross cystic breast disease is a benign condition affecting about 7-10% of adult women occurring with the highest incidence in the premenopausal decade. Although breast cysts do not represent a preneoplastic condition per se, several studies indicate an increased breast cancer risk in women affected by this pathology. In this report we study 115 breast cystic fluid samples obtained by needle-aspiration from women with gross cystic breast disease. The samples were analysed biochemically and the cells contained therein were observed at the electron microscope. According to their biochemical profiles, the cysts were subdivided into three types: Type I, showing a Na/K ratio < 0.5 and a typical protein content; Type II, showing a Na/K ratio >10 and a protein content quite similar to plasma; Type III, showing a Na/K ratio between 1 and 7 and an intermediate protein content. The electron microscopic examination demonstrated that Type I cystic fluid cells exhibit morphological features typical of actively synthesising and secreting cells, while the characteristics of Type II cells indicate a low metabolic activity. Type III cells have characteristics typical of both Type I and Type II cells, thereby confirming the intermediate nature of this cyst type. We hypothesise that these cyst types could represent different developmental stages of a structural evolution pathway, during which the biosynthetically active 'apocrine stage' would be the key step to cell neoplastic transformation.

Prostate-specific antigen expression in a case of intracystic carcinoma of the breast: characterization of immunoreactive protein and literature surveys

A case is presented of female breast intracystic carcinoma with prostate-specific antigen (PSA) expressed in high amounts in aspirated cystic fluid (55 micrograms/L). Tumor extract analysis revealed the presence of both estrogen and progesterone receptors (0.38 and 1.87 nmol/L, respectively) and high quantities of PSA too (19.52 micrograms/L). Chromatographic analysis of cystic fluid revealed two peaks of PSA, at the expected positions for free and bound serine protease. A major proportion of 33-kDa free from was also confirmed by Western blotting analysis. Free PSA was heat-stable at 56 degrees C and displayed no change after freezing-thawing. These findings are discussed in the context of a detailed literature survey. Our data support the contention that PSA immunoreactivity in intracystic fluid of breast carcinoma is partly the result of secretory activity by the neoplastic cells and that the steroid receptors can also modulate its expression.

Quantification of prostate-specific antigen immunoreactivity in human breast cyst fluids

The frequency of gross cystic breast disease in premenopausal women and its possible association with increased breast cancer risk emphasises the importance of investigations relating to breast cyst fluid composition. In order to contribute to a better analysis of this medium, we have measured the presence of prostate-specific antigen immuno-reactivity in sixty-four human breast cyst fluids. Data analyses show that 35% of samples presented a level of this antigen < 0.05 micrograms/L, whereas 42 out of 64 cysts show a significant increase in the mean value of metabolically active apocrine cysts when compared to flattened cysts (p < 0.01). We report the first evidence that breast epithelium of gross cysts produces, secretes, and accumulates large amounts of prostate-specific antigen, a glycoprotein produced by prostatic tissue but recently detected in breast tumours, normal tissues, and during pregnancy. The production and intracystic accumulation of this serine protease in biosynthetically active apocrine type cyst can play a feasible role in the natural history gross cystic breast disease as well as in the mechanism of cyst formation, enlargement, and transformation.

Promotion of tumour metastases and induction of angiogenesis by native HIV-1 Tat protein from BK virus/tat transgenic mice

OBJECTIVE

To characterize the T53 cell line and its clones derived from an adenocarcinoma of BK virus (BKV)/tat transgenic mice and to establish the role of native Tat in tumorigenicity, induction of metastases and angiogenesis.

DESIGN AND METHODS

Tat was quantified by flow cytometry and chloramphenicol acetyltransferase (CAT) assays. Tumorigenicity and metastatic ability of cell lines were assayed in nude mice. Production of proteases was evaluated by a plasmin chromogenic assay and gelatinase zymography. The angiogenic effect was studied in vivo with conditioned medium from tumour cell lines.

RESULTS

Tat protein was detected in tumour cell lines in amounts from 600-7000 molecules/cell. Conditioned medium from tumour cell lines was able to transactivate an LTR-CAT in HL3T1 cells, indicating release of extracellular Tat. Tumour cell lines, inoculated into nude mice induced angiogenic tumours with remarkable recruitment of host endothelial cells. Metastases were detected in lymph nodes, lungs, kidneys, and heart. Cell lines produced relevant amounts of proteases. Conditioned medium implanted in mice with matrigel induced an angiogenic response, enhanced by addition of heparin. Preincubation with an anti-Tat antibody abolished the angiogenic effect.

CONCLUSIONS

Tat from cells from BKV/tat transgenic mice promotes tumorigenesis and formation of metastases and induces angiogenic activity. Angiogenesis occurs at physiological concentrations of Tat lower than 20 ng/ml. The effects of Tat on induction of metastases and angiogenesis appear to be mediated by activation of proteases.

Lipids status in human breast cyst fluids

Benign mammary gross cystic disease is the most common breast lesion; women with apocrine changes of epithelium lining the cysts are at higher risk for developing breast cancer than the normal population. Total cholesterol, high- and low-density lipoproteins fractions, triglycerides and phospholipids, lipase activity and total lipid concentrations were measured in cyst fluids and sera from 89 women affected by gross cystic breast disease. Total cholesterol and high-density lipoprotein content were significantly (P < 0.001) greater in pooled cyst fluids than normal sera. Moreover, data analyses show a significant increase in the mean values of total lipids and lipase activity in metabolically active apocrine cysts, when compared to the flattened cysts (P < 0.001). The lipids feature of apocrine cysts could represent an altered expression of biosynthetic activity of the surrounding apocrine cell surface glycolipid and steroidogenic metabolism and may provide further knowledge about the functional stage changes of gross breast cysts.

beta-Endorphin expression in gross cystic breast disease

Opioid peptides have a variety of pathophysiologic actions, playing a novel important role in human breast cancer. The expression of beta-endorphin was studied in 84 human breast cyst fluids from gross cystic breast disease-affected patients. The concentration of beta-endorphin in pooled breast cyst fluids was over four-fold higher than in respective plasma with a significant increase in the mean value of the 'metabolically active' apocrine cysts when compared with flattened cysts (P < 0.001). The higher levels of Type I cyst suggest de novo mammary synthesis of endogenous opioid peptides and could represent an altered expression of biosynthetic activity of apocrine breast cells, providing a possible explanation on functional changes of gross cysts, on the mechanism of their formation and a perspective relationship to breast cancer risk.

Hydrogen peroxide cytotoxicity under conditions of normal or reduced catalase activity in H2O2-sensitive and -resistant Chinese hamster ovary (CHO) cell variants

H2O2-sensitive and -resistant sublines of Chinese Hamster Ovary (CHO) cells were tested for their sensitivity to the growth inhibitory effect elicited by increasing concentrations of the oxidant under conditions of normal or reduced catalase activity. Experimental results have demonstrated that, under conditions of reduced catalase activity, the cytotoxic action of H2O2 was differentially regulated in resistant and sensitive cells. Indeed, the parental cell line and cells resistant to low concentrations of H2O2 (V 250 cells) depended on catalase to a lower extent than did highly resistant cells (V 850 cells). It is interesting to note that V 250 cells had more catalase, on a per million cell basis, than V 850 cells. We conclude that acquired resistance to oxidative stress is not entirely dependent on catalase and that the contribution of catalase depends on the degree of resistance to the oxidant.

Goat immunoglobulin purification on phosphocellulose and DEAE Affi-Gel blue

We describe a method for the efficient purification of immunoglobulins G (IgG) to near homogeneity from goat serum. This was achieved by performing first an AS-40 fractionation on goat serum, followed by chromatography on phosphocellulose (P11) equilibrated in citrate buffer at pH 5.7. Peak I, eluted at V0 from P11, contained all IgG and the other serum proteins, except beta-globulins and most of the alpha-2-globulins, which are eluted in a second peak with 0.24 M K-phosphate in citrate buffer at pH 6.0. Peak I, concentrated and dialyzed in 20 mM K-phosphate buffer pH 8.0, was then applied onto a DEAE Affi-Gel Blue column equilibrated in the same buffer. Two peaks were obtained from this column: peak I, eluted at V0 contained a pure IgG fraction, while the other serum proteins were in peak II. We conclude that the P11 step, performed under the conditions we report here, is very useful to retain the alpha-2 and beta-globulins, which contaminate the IgG when only the DEAE Affi-Gel Blue purification step is used.