[Promoting the quality of health surveillance of workers exposed to wood dust, with particular care to NPSC, in the territory of the Health Agency of Florence]. / Promozione della qualità della sorveglianza sanitaria dei lavoratori esposti a polvere di legno, con particolare riferimento ai TuNS, nel territorio di competenza della Azienda Sanitoria di Firenze.

Wood dust can cause occupational-related naso-sinusal cancer, characterized by a latency period of about 40 years. The Tuscany Cancer Registry estimates that cases of NPSC are from 20-25 per year into the Region (33% related to wood dust). These neoplasms are surgically treatable at early-stage and, for this reason, a rapid endoscopic diagnosis is considered to be reasonably useful for prognostic issues. We used a questionnaire to investigate nasal symptoms and NOSQ and SOLAR questionnaires to highlight respiratory/skins diseases, and a spirometry for each worker. Subjects with a working-age of more than 15 years, and those that were positive to the questionnaire and/or to the medical history were were referred to a specialist in otolaryngology. The prevalence of endoscopic positive findings--detected especially in subjects with a working age of more than 15 years--confirms the significance of the problem.

Acrylamide disrupts elemental composition and water content of rat tibial nerve. III. Recovery.

We have previously demonstrated that subacute and subchronic acrylamide (ACR) intoxication are associated with a loss of subcellular elemental regulation in myelinated axons and Schwann cells of rat tibial nerve (LoPachin et al., Toxicol. Appl. Pharmacol. 115, 21-34, 1992; LoPachin et al., Toxicol. Appl. Pharmacol. 115, 35-43, 1992). In the present study, rats were allowed to recover partially from subchronic oral ACR intoxication (2.8 mM in drinking water for approximately 30 days). Elemental composition and water content of tibial nerve myelinated axons and Schwann cells were measured by electron probe X-ray microanalysis. Results show that K and Cl concentrations in larger tibial nerve axons were shifted toward normal values or above. For the most part, small axons also exhibited elemental changes that reflected recovery from ACR intoxication. Mitochondria displayed elemental changes that were similar to corresponding axoplasm. Schwann cells in tibial nerve of recovering animals had altered Na, P, Cl, K, and Mg concentrations that were similar in magnitude and extent to those occurring during ACR intoxication. In contrast, myelin displayed few changes. These results suggest that the recovery process following ACR intoxication is associated with characteristic changes in subaxonal elemental composition that might be related to repair mechanisms. That recovery-related elemental changes differ from those associated with intoxication provides additional support for the hypothesis (LoPachin et al., Toxicol. Appl. Pharmacol. 115, 21-34, 1992) that perturbation of elemental regulation is a specific component of ACR neurotoxicity. The observation of persistent Schwann cell disruption during recovery might reflect either long-term secondary consequences or delayed recovery from direct injury. Further studies are necessary to resolve this issue.

Effects of acrylamide on subcellular distribution of elements in rat sciatic nerve myelinated axons and Schwann cells.

Electron probe X-ray microanalysis was used to determine whether experimental acrylamide (ACR) neuropathy involves deregulation of subcellular elements (Na, P, S, Cl, K, Ca and Mg) and water in Schwann cells and small, medium and large diameter myelinated axons of rat sciatic nerve. Results show that in proximal but not distal sciatic nerve, ACR treatment (2.8 mM in drinking water) was associated with an early (15 days of exposure), moderate increase in mean axoplasmic K concentrations (mmol/kg) of medium and small diameter fibers. However, all axons in proximal and distal nerve regions displayed small increases in dry and wet weight contents of axoplasmic Na and P. As ACR treatment progressed (up to 60 days of exposure), Na and P changes persisted whereas proximal axonal K levels returned to control values or below. Alterations in mitochondrial elemental content paralleled those occurring in axoplasm. Schwann cells in distal sciatic nerve exhibited a progressive loss of K, Mg and P and an increase in Na, Cl and Ca. Proximal glia displayed less extensive elemental modifications. Elemental changes observed in axons are not typical of those associated with cell injury and might reflect compensatory or secondary responses. In contrast, distal Schwann cell alterations are consistent with injury, but whether these changes represent primary or secondary mechanisms remains to be determined.

Ganglioside treatment modifies abnormal elemental composition in peripheral nerve myelinated axons of experimentally diabetic rats.

Effects of ganglioside administration on elemental composition of peripheral nerve myelinated axons and Schwann cells were determined in streptozotocin-induced diabetic rats and nondiabetic controls. Diabetic rats (50 days after administration of streptozocin) exhibited a loss of axoplasmic K and Cl concentrations in sciatic nerve relative to control, whereas intraaxonal levels of these elements increased in tibial nerve. These regional changes in diabetic rat constitute a reversal of the decreasing proximodistal gradients for K and Cl concentrations that characterize normal peripheral nerve. Treatment of diabetic rats with a ganglioside mixture for 30 days (initiated 20 days after the administration of streptozocin) returned proximal sciatic nerve axoplasmic K and Cl concentrations to control levels, whereas in tibial axons, concentrations of these elements increased further relative to diabetic levels. Also in the ganglioside/diabetic group, mean axoplasmic Na concentrations were reduced and Ca levels were elevated. Mixed ganglioside treatment of nondiabetic rats significantly increased axoplasmic dry weight concentrations of K and Cl in proximal sciatic and tibial axons. Schwann cells did not exhibit consistent alterations in elemental content regardless of treatment group. Changes in elemental composition evoked by ganglioside treatment of diabetic rats might reflect the ability of these substances to stimulate Na+,K(+)-ATPase activity and might be related to the mechanism by which gangliosides improve functional deficits in experimental diabetic neuropathy.

Effects of serotonin and carbachol on glial and neuronal rubidium uptake in leech CNS.

Effects of serotonin (5-HT) and carbachol on Rb uptake (used as a K marker) in leech neuron and glia were studied by electron probe microanalysis (EPMA). Hirudo medicinalis ganglia were perfused 60 s in 4 mM Rb substituted normal leech Ringer's with and without 5-HT (dosage range 5-500 microM) or carbachol (range 10-1000 microM), quench frozen cryosectioned, and subjected to EPMA to determine elemental mass fractions and cell water content. Both 5-HT and carbachol altered leech neuron and glial cell elemental distribution and water content. In glial cells, a dose-dependent increase in Rb uptake was observed following 5-HT (control: 26 +/- 2 microM; 5 microM: 47 +/- 4; 50 microM: 62 +/- 4; 500 microM: 82 +/- 11 mmol/kg dry wt. +/- S.E.M.) and carbachol (10 microM: 35 +/- 3; 100 microM: 52 +/- 3; 1000 microM: 68 +/- 3 mmol/kg dry wt. +/- S.E.M.). In neurons, 5-HT and carbachol had small effects. 5-HT decreased glial and neuronal cell water content. Carbachol decreased neuronal (but not glial) water content by approximately the same amount (mean decrease 9%) regardless of dose. Both 5-HT and carbachol affected glial cell K-accumulating properties, providing evidence that certain neurotransmitters may modulate invertebrate glial cells' K clearance function.

Acrylamide disrupts elemental composition and water content of rat tibial nerve. I. Myelinated axons.

The mechanism by which acrylamide (ACR) produces distal axonopathy in humans and laboratory animals is unknown. The possibility that this neuropathy involves deregulation of elements and water in rat peripheral nerve has been investigated. Electron probe X-ray microanalysis was used to measure percentages of water and concentrations (mmol element/kg dry or wet wt) of Na, P, S, Cl, K, Ca, and Mg in axoplasm and mitochondrial areas of tibial nerve axons. Results show that when rats were intoxicated with ACR by either the oral (2.8 mM in drinking water, up to 60 days) or the intraperitoneal (ip, 50 mg/kg/day x 5 or 10 days) route, a progressive loss of internodal axoplasmic K, Cl, and Na regulation was observed in subpopulations of myelinated fibers. Elemental deregulation was manifest as a shift in mean elemental content, widening of the corresponding concentration range, and a statistically significant increase in data variance. In internodal axonal regions, elemental composition of mitochondrial areas was not altered by ip ACR intoxication, whereas oral exposure was associated with delayed changes in Na, K, Cl, Ca, and Mg. In swollen axons, axoplasm and mitochondrial areas exhibited complete loss of element and water compartmentalization. This global decompartmentalization of swollen axons was quantitatively similar regardless of the route or length of ACR exposure. The results of this study suggest that a progressive loss of elemental regulation in axoplasm of myelinated tibial nerve fibers might be mechanistically related to ACR neurotoxicity.

Acrylamide disrupts elemental composition and water content of rat tibial nerve. II. Schwann cells and myelin.

The effects of subchronic and subacute acrylamide (ACR) intoxication on elemental composition (Na, P, S, Cl, K, Ca, Mg) and water content of Schwann cell body cytoplasm and myelin were assessed in rat tibial nerve. Electron probe X-ray microanalysis demonstrated that, in control rats, peripheral nerve glia and myelin exhibited highly characteristic distributions of elements and water and that ACR intoxication was associated with disruption of this normal subcellular distribution. When rats were intoxicated with ACR by either the oral (2.8 mM in drinking water for 15, 22, 30, and 60 days) or the intraperitoneal (50 mg/kg/day x5 and 10 days) route, an exposure-dependent loss of cytoplasmic Na, K, P, Cl, Mg, and water regulation was detected in Schwann cell cytoplasm. Maximum development of elemental deregulation occurred after 30 days of oral ACR exposure and 10 days of ip treatment. The cytoplasmic elements involved and their corresponding quantitative changes were similar regardless of the route of ACR intoxication. Analysis of myelin revealed that both oral and parenteral ACR exposure caused early, persistent increases in dry weight Na, P, and water content. However, Cl dry weight concentrations were increased by oral exposure and decreased by ip ACR injection. Results of this study indicate that ACR intoxication is associated with a significant disturbance of subcellular element and water distribution in tibial nerve Schwann cells and myelin. The pattern of elemental disruption is typical of reversible cell damage and, therefore, Schwann cell injury might play a role in the expression of ACR neurotoxicity.

Preferential uptake of rubidium from extracellular space by glial cells compared to neurons in leech ganglia.

Glial cells play a significant role in maintaining extracellular space (ECS) potassium (K) by temporarily buffering or accumulating excess ECS K and then returning that K to neurons. Yet, little is known about the relative affinity of neurons or glial cells for K when both cells are simultaneously exposed to the same ECS K, in situ. Also, the process by which glial cells return K to neurons remains unknown. Therefore, electron probe X-ray microanalysis was used to measure rubidium (Rb) uptake, as a K tracer, into leech packet neurons and glial cells, and to measure the distribution of cell water content, K, Na and Cl. When ECS Rb was increased from 4 mM to 20 mM, there was a clear preferential Rb uptake into glial cells compared to neurons. At 4 mM extracellular Rb there was only a small difference between uptake velocity of neurons and glial cells (maximum mean uptake velocity at 4 mM Rb was 1.09 for glia, and 0.41 mmol Rb/kg dry wt/s for neurons), whereas at 20 mM extracellular Rb, glial uptake velocity was dramatically greater than of neurons (max. mean Rb uptake velocity for glia was 4.3 compared to 1.47 mmol Rb/kg dry wt/s for neurons). Glial Rb uptake velocity was enhanced by low temperature (max. mean Rb uptake velocity at 20 mM ECS Rb at 6 degrees C was 6.04 for glia compared to 0.78 mmol Rb/kg dry wt/s for neurons) and by substitution of Cl with isethionate (max. mean Rb uptake velocity was 10.6 for glia compared to 1.33 mmol Rb/kg dry wt/s for neurons).(ABSTRACT TRUNCATED AT 250 WORDS)

Perturbation of axonal elemental composition and water content: implication for neurotoxic mechanisms.

The concentration and distribution of labile elements in nerve cells is tightly regulated by multiple membrane transport processes and by binding to lipids and proteins. The multifaceted nature of elemental regulation provides numerous sites at which toxicants or disease processes might act to disrupt this regulation. Such disruption can affect cytoskeletal integrity, macromolecular synthesis, energy production, osmoregulation and other cellular processes. The possible role of perturbed elemental homeostasis in the mechanism of nerve injury caused by certain chemicals (e.g., acrylamide, 2,5-hexanedione) and neuropathic diseases (e.g., diabetes) has not been determined. To investigate this possibility, we have used electron probe x-ray micro-analysis (EPMA) to measure the distribution of elements and water in cellular compartments of myelinated axons (axoplasm, mitochondria) and glial cells (cytoplasm, myelin) in normal rat central and peripheral nervous systems. Results indicate that each compartment exhibits a characteristic composition of elements and water which might reflect function of that anatomical region or organelle. Injury-induced changes in elemental content of PNS axons and Schwann cells have been identified using several neurotoxic models (i.e., acrylamide, axotomy, diabetic neuropathy). Each type of injury initiated early alterations in element and water composition of both axons and glial cells. Compositional changes were specific and developed sequentially instead of simultaneously. Results of these studies suggest that, rather than being an epiphenomenon, altered elemental regulation might represent a primary component of many neurotoxic mechanisms.

Elemental composition and water content of myelinated axons and glial cells in rat central nervous system.

The distribution of elements (e.g. Na, Cl, K) and water in CNS cells is unknown. Therefore, electron probe X-ray microanalysis (EPMA) was used to measure water content and concentrations (mmol/kg dry or wet weight) of Na, Mg, P, S, Cl, K and Ca in morphological compartments of myelinated axons and glial cells from rat optic nerve and cervical spinal cord white matter. Axons in both CNS regions exhibited similar water content (approximately 90%), and relatively high concentrations (wet and dry weight) of K with low Na and Ca levels. The K content of axons was related to diameter, i.e. small axons in spinal cord and optic nerve had significantly less (25-50%) K than larger diameter axons from the same CNS region. The elemental composition of spinal cord mitochondria was similar to corresponding axoplasm, whereas the water content (75%) of these organelles was substantially lower than that of axoplasm. In glial cell cytoplasm of both CNS areas, P and K (wet and dry weight) were the most abundant elements and water content was approximately 75%. CNS myelin had predominantly high P levels and the lowest water content (33-55%) of any compartment measured. The results of this study demonstrate that each morphological compartment of CNS axons and glia exhibits a characteristic elemental composition and water content which might be related to the structure and function of that neuronal region.

A comparison of methods for analysis of mRNA in hematopoietic cells: conventional and clonal northern analysis and in situ hybridization.

Three methods for the detection of mRNA in hematopoietic cells are addressed, and examples using these techniques to examine human leukemic cells' genetic response to chemical and biological response modifiers shown. The limitations and specific applications of the three techniques are discussed.

Detection of RNA transcripts in normal lymphoid and myeloid colonies.

A procedure is described for the routine detection of RNA transcripts in small numbers of hematopoietic cells growing in semi-solid agar. It is suggested that hybridization depends upon RNA expression and that as few as 2500 mRNA molecules per colony are easily detected. Applications of this technique are described in three diverse experimental systems; immunoglobulin gene expression in B cell colonies; neo expression in normal and transformed B cell clones derived from multipotent stem cells infected with a neo-containing retrovirus; and c-myc expression in factor-dependent myeloid colonies.

Chronic T lymphocytic leukaemia: antigenic, morphological and functional properties of the neoplastic lymphocytes.

We describe 2 cases of T cell leukaemia. Both patients react with OKT 4 monoclonal antibody, while their clinical course, surface markers and in vitro immunological reactivity present opposite behaviour. The cells of 1 patient react with all pan T cell markers (OKT 3, OKT 11, Leu 1), from E and Ea rosettes and respond well to mitogens. This patient does not present liver, spleen or lymph node enlargement; white cell count is stable and no other haematological alterations are present. The cells from the 2 patient are unreactive with OKT 3 and are unable to form Ea rosettes. The response to mitogens is almost abolished. The disease has an aggressive clinical course with progressively increasing blood leucocyte count and infiltration of liver and spleen. These data suggest that the study of antigenic and functional properties of T CLL may be useful to better define the biologic characteristics and the prognostic criteria of the disease.

Enumeration of human lymphocyte subsets by monoclonal antibodies and flow cytometry: a comparative study using whole blood or mononuclear cells separated by density gradient centrifugation.

Enumeration of lymphocyte subpopulations by combined use of flow cytometry and monoclonal antibodies is influenced by the separation method used. T or B lymphocyte antigen frequencies do not differ in samples of whole blood or after separation on Ficoll-Paque or Percoll, but there is a significant increase of Leu+ Leu11+ lymphocytes showing strong natural killer activity at the sample-separation medium interface. At the bottom of the tubes a selective loss of OKT+, Leu7+, Leu11- cells is found; at this level cytotoxicity is very low. Our data suggest that Leu7+ cells could be subdivided into 2 subpopulations differing in reactivity with the monoclonal antibody to Leu11, natural killer activity and density. Differences observed in the percentages of Leu7+, Leu11+ lymphocytes between whole blood and separated cells could be due to an enrichment produced by centrifugation or to the presence in whole blood of a factor interfering with antibody binding.

Alteration of T cell subsets during tetanus infection treated with high doses of specific immunoglobulins.

Peripheral blood lymphocytes of 8 tetanus patients have been studied with monoclonal antibodies and flow cytometry. During the progression of the disease OKT3+ and Leu7+ cells undergo significative daily variations and OKT4+ cells become the majority of peripheral blood T cells. In two patients is present a severe T lymphopenia and one of these subjects presented a more prolonged disease compared to the other ones. B cells are greatly increased after 10-12 days. Two possibilities could be considered to explain our data: firstly a direct effect of the tetanic infection on the recirculation of lymphocytes producing also an expansion of OKT4+ cells containing a helper population; secondly the observed alterations of lymphocytes subsets are not due to the infection itself but rather to the massive administration of specific immunoglobulins to these patients.

Peripheral blood and bone marrow lymphocytes of B chronic lymphocytic leukaemia patients.

The percentages of lymphocytes subpopulations were assessed in the peripheral blood and bone marrow of B chronic lymphocytic leukaemia patients with monoclonal antibodies and flow cytometry. The absolute number of peripheral T cells is higher compared to healthy subjects; the imbalance of OKT 4 and OKT 8 positive subsets in peripheral blood is characterized by an inversion of the T 4/T 8 ratio. T 4 positive cells are predominant in the bone marrow; the Leu 7 positive population is increased in absolute numbers. These precocious phenomena could be important in the immunodeficiency associated with B CLL and/or in the progression of the disease.

Effects of adenovirus infection on rRNA synthesis and maturation in HeLa cells.

The production of cytoplasmic and nucleolar rRNA species was examined in HeLa cells infected with high multiplicities of adenovirus type 5. Both 28S and 18S rRNA newly synthesized in infected cells ceased to enter the cytoplasm as reported previously (N. Ledinko, Virology 49: 79-89, 1972; H. J. Raskas, D. C. Thomas, and M. Green, Virology 40: 893-902, 1970). However, the effects on 28S cytoplasmic rRNA were observed considerably earlier in the infectious cycle than those on 18S rRNA. The inhibition of cellular protein synthesis and of the appearance in the cytoplasm of labeled cellular mRNA sequences (G. A. Beltz and S. J. Flint, J. Mol. Biol. 131: 353-373, 1979) were also monitored in infected cultures. During the later periods of an infectious cycle, from 18 h after infection, nucleolar rRNA synthesis and processing and exit of 18S rRNA from the nucleus were inhibited, probably reflecting the failure of infected cells to synthesize normal quantities of ribosomal proteins. The earliest responses of cellular RNA metabolism to adenovirus infection were, however, the rapid and apparently coordinate reductions in the levels of newly synthesized 28S rRNA and cellular mRNA sequences entering the cytoplasm.