Larynx morphology and sound production in three species of Testudinidae.

Although the ability to vocalize is widespread among tortoises, the mechanisms of sound production in chelonians remain undescribed. In this study, we analyze the morphology and histology of the larynx of three species of Testudinidae (Testudo hermanni, T. graeca, and T.

Expression of natriuretic peptides, nitric oxide synthase, and guanylate cyclase activity in frog mesonephros during the annual cycle.

Natriuretic peptides (NPs), a family of structurally related hormones and nitric oxide (NO), generated by nitric oxide synthase (NOS), are believed to be involved in the regulation of fluid balance and sodium homeostasis. Differential expression and regulation of these factors depend on both physiological and pathological conditions. Both NPs and NO act in target organs through the activation of guanylate cyclase (GC) and the generation of guanosine 3',5'-cyclic monophosphate (cGMP), which is considered a common messenger for the action of these factors.

Quantification of the DHFR gene in blast cells of leukaemia patients by fluorescence in situ hybridisation.

The fluorescence signal intensity of the DHFR gene was analysed in lymphocytes from 15 normal donors, in MTX-resistant HeLa cells (carrying DHFR gene amplification) and in bone marrow blasts from 16 patients with acute leukaemia (AL) by in situ hybridisation. Our aim was to verify if DHFR gene amplification may be responsible for increased enzyme activity in leukemic cells. The results obtained with a fluorescence in situ hybridisation method were quantified using the Scion image software program and compared with cytochemical and cytophotometric data relating to DHFR activity.

Stem cell recruitment and liver de-differentiation in MMTV-neu (ErbB-2) transgenic mice.

The liver of tumor-bearing hosts manifests fetal phenotypes. We investigated the expression of differentiation markers on the liver in MMTV-neu (ErbB-2) transgenic mice, in the period from incipient neoangiogenesis to lung metastatization. We report AFP expression by hepatocytes in all lobular zones, CD34 cell arrest and subsequent hemopoiesis in periportal and mid-zone areas, oval-like cells (CD34+, CK19+, AFP+) and ductular reaction in portal tracts, portal CK19+ and GGT+ hepatoblast-like cells, and midzonal large dysplastic hepatocytes.

Evaluation of serum levels of cytokines and intercellular adhesion molecule-1 (ICAM-1) in astrocytic tumours.

Soluble form of intercellular adhesion molecules (sICAM) are increased in serum of many inflammatory diseases and tumours: the expression of such molecules is regulated by cytokines. In the present paper serum levels of interleukin-2 (IL-2), soluble interleukin-2 receptor (sIL-2R) and sICAM-1 were evaluated in patients with glioma compared with different tumours (lung and kidney carcinoma) in order to investigate the compromise of the immune system in these malignancies and to understand the host defence mechanisms. 14 cases of astrocytomas (WHO grade II, III), 20 cases of glioblastomas (GBL, WHO grade IV), 5 cases of lung carcinoma and 6 cases of kidney carcinoma were studied; the results were compared with 15 healthy controls.

Styrene hepatotoxicity in rats treated by inhalation or intraperitoneally: a structural investigation.

The purpose of this study was to investigate the toxicity of styrene in the liver of adult rats treated either by inhalation of styrene vapour (300 ppm, 6 h/d, 5 d/wk, for 2 wk) or intraperitoneally with different styrene doses (4, 40, 400 mg/Kg) for 3 consecutive days. Using a light microscope, some alterations of liver parenchyma and sinusoid dilation were noticed, more marked in the group treated with the intraperitoneal administration of the chemical. Using an electron microscope, some additional changes were observed (once again, more marked in the latter group of rats): a) an increase in the content of lipids inside hepatocytes, and b) the rise of intracytoplasmic, intercellular and perisinusoidal collagen fibres.

Hemopoiesis in the liver of adult tumor-bearing mice.

In the liver of adult mice bearing an Ehrlich carcinoma on the leg, progressively hypoxic and displaying reactive hepatitis but not metastatic dissemination, extramedullary hemopoiesis was detected. Electron microscopy revealed mainly erythropoietic islands and scattered megakaryocytes in maturation stages up to the platelet-releasing phase. Erythropoietic cells expressed an embryonic-type of hemoglobin, which is more adequate to oxygenate hypoxic environments than the adult type.

Increase in liver pigmentation during natural hibernation in some amphibians.

The amount/distribution of liver melanin in 3 amphibian species (Rana esculenta, Triturus a. apuanus, Triturus carnifex) was studied during 2 periods of the annual cycle (summer activity-winter hibernation) by light and electron microscopy, image analysis and microspectrofluorometry. The increase in liver pigmentation (melanin content) during winter appeared to be correlated with morphological and functional modifications in the hepatocytes, which at this period were characterised by a decrease in metabolic activity.

Comparison of K(+)-p-nitrophenyl phosphatase activity in the urinary bladder of the frog Rana esculenta during hibernation and active life.

We have studied effects of hibernation on the frog urinary bladder, an organ involved in water and ion transepithelial transport and taking part in osmoregulation. We have demonstrated K(+)-p-nitrophenyl phosphatase activity (an enzyme involved in ion and water transport) both in active and hibernating frogs. Most of the reaction product deposition was found on basolateral membranes of granular cells of the urinary bladder epithelium during all seasons.

Ultrastructural changes of neutrophils following IL-2 treatment in vivo.

An ultrastructural analysis of peripheral blood cells of cancer patients following recombinant interleukin-2 (rIL-2) treatment at high doses (rIL-2, 18 x 10(6) I.U./m2/day) has been performed.

Tumor interstitial fluid: misconsidered component of the internal milieu of a solid tumor.

The tumor interstitial fluid (TIF) is a fluid phase present in the extracellular space of all tumors whose importance in oncology is seldom recognized. In order to stimulate other researchers to give it the due importance, a review of the available data (including our own) is provided. An hypothesis is presented for the genesis, fate and role of the TIF in the processes of invasion, growth and metastatization.

Characterization of the metabolism of perinecrotic cells in solid tumors by enzyme histochemistry.

Hypoxic tumor cells resist most therapies and cause tumor regrowth when their environment improves. Identifying the adaptation strategies to hypoxia would help develop better tailored cancer therapies. Ehrlich carcinomas implanted on mice were analyzed histochemically for the following enzyme activities: lactate, succinate and glucose-6-phosphate dehydrogenases, dihydrofolate reductase, purine nucleoside phosphorylase, xanthine oxidoreductase, and acid phosphatase.

Morphofunctional characterization of lymphokine activated killer (LAK) cells in vitro.

In order to characterize the cellular subsets of peripheral blood lymphocytes cultured with interleukin-2 (IL-2), a study in vitro was developed. Both conditioned medium from PHA-stimulated lymphocytes and recombinant IL-2 (rIL-2) were employed. The following aspects were examined: the morphological pattern of IL-2 stimulated lymphocytes; the ability of these cells to recognize, bind, attack and destroy tumoral lines; their cytochemical and immunological (CD) feature.

Enzyme histochemical studies on tumor blood vessels.

The oxygenation, the growth rate and the metastatic potential of a solid tumor depend on its vascularization and, in particular, on angiogenesis; a therapeutic approach affecting angiogenesis has been suggested as an alternative to conventional ones. Especially the study of the metabolism in the cells of the vessel wall should be a useful prerequisite for this approach. In this connection, an enzyme histochemical study was performed to characterize the blood vessels in a solid tumor (Ehrlich carcinoma).

Neuroprotective effects of alpha-dihydroergocryptine against damages in the substantia nigra caused by severe treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

The effects on the substantia nigra of alpha-dihydroergocryptine (DEK), a drug with strong dopaminomimetic activity, were tested with a severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in monkeys. Compared with monkeys treated with MPTP alone, the animals which received DEK plus MPTP showed reduced neuronal death in the substantia nigra. The reactive astrocytes were increased in number.

Immunohistochemistry of dihydrofolate reductase in methotrexate-sensitive and -resistant human cell lines by flow cytometry: a comparison with the cytochemical tetrazolium salt method.

Dihydrofolate reductase (DHFR, EC 1.5.1.

Stroma formation in Ehrlich carcinoma. I. Oedema phase. A mitosis burst as an index of physiological reoxygenation?

Tumor stroma induction has been shown closely to resemble wound repair process, both involving the replacement of a fibrin gel by vascularized connective tissue. In such a process the initial phase of hyperpermeability of blood vessels leads to diffuse oedema. It is here reported that cell loosening and a remarkably high mitotic burst were observed in Ehrlich carcinoma in regions in contact with the exudate, particularly at the perinecrotic (hypoxic) region.

Modulation of cytochemically detected dihydrofolate reductase during cell cycle.

Dihydrofolate reductase (DHFR, EC 1.5.1.

Histochemical probes for the detection of hypoxic tumour cells.

Hypoxia is thought to be a major cause of failure in cancer treatment. In this paper, we report methods transposable to clinical practice, for identifying hypoxic tumour cells. They consist of histochemical tests for revealing lactate dehydrogenase activity, endogenous lactate and accumulation of neutral fat.

DNA double staining for a fluorescence energy transfer study of chromatin in liver cells.

Methodological aspects related to the application of techniques based on fluorescence energy transfer in the study of chromatin structure, were first examined. Fluorochromes specific for DNA with different interaction mechanisms were employed, both in single and double stainings. The following dye pairs were considered as donor/acceptor couples: Hoechst 33342 or DAPI/Mithramycin A or Chromomycin A3, Hoechst 33342 or DAPI/Propidium Iodide, and Mithramycin A or Chromomycin A3/Propidium Iodide.

A qualitative and quantitative assay of dihydrofolate reductase in carrot cells resistant to methotrexate.

The cytochemical pattern and the quantitative assay of DHFR on Daucus carota cell lines sensitive and resistant to methotrexate (MTX) are described. Cytoplasmatic enzyme activity is evidenced as granules of formazan, final reaction product, in the majority of the cells. DHFR activity appears low in Daucus carota cells used as control while in carrot cells resistant to MTX is very high, an observation which parallels previous biochemical studies.

The action of cisplatinum (cis-DDP) on the postnatal growth of the rat liver. Cytokinetics and ultrastructural studies.

The early and late effects of cis-DDP treatment on liver cell kinetics were analyzed after its intraperitoneal injection into 17-day old rats. Frequency of binucleate hepatocytes, cellular DNA content distribution, 3H-thymidine labelling and ultrastructure of the nuclei were analyzed. Two days after treatment, a block of mononucleate hepatocytes in the S phase and in the G2 phase was demonstrated by the increase of intermediate 2c-4c and 4c DNA values in the absence of changes in 3H-thymidine labelling; 8c binucleate cells, which are essential for the formation of tetraploid mononucleate cells, were not found.

A qualitative and quantitative cytochemical assay of dihydrofolate reductase in erythroid cells.

The distribution and intensity of dihydrofolate reductase (DHFR) cytochemically demonstrable was studied in erythroid cells. Cells of normal human bone marrow, of human erythroleukaemia (M6), and cells of the Friend (MEL) clone 745A murine erythroleukaemia (also after differentiation with dimethylsulphoxide, DMSO) were stained according to Gerzeli and de Piceis Polver (1969) technique; quantification of the reaction product was made using a Vickers M86 microdensitometer. The enzyme activity progressively decreased during the normal differentiation of the erythropoietic series while persisted at high levels in erythroleukaemia cells.