Paola De Piceis Polver

STYRENE-INDUCED ALTERATIONS IN THE RESPIRATORY TRACT OF RATS TREATED BY INHALATION OR INTRAPERITONEALLY

Although exposure to styrene occurs primarily via inhalation, the action of this agent on the respiratory tract has scarcely been investigated. This article describes morphological and biochemical changes occurring in the respiratory tract of rats after either inhalation of styrene vapors (300 ppm, 6 h/d, 5 d/wk, for 2 wk) or systemic (ip) treatment with 40 or 400 mg/kg styrene for 3 consecutive days. Electron microscopy analysis showed diffuse cell damage involving the tracheal, bronchiolar, and alveolar epithelium. In the tracheal epithelium, several cell types were affected. Ciliated cells presented vacuolation, detachment of cilia, blebbing of the apical cytoplasm, and compound cilia. Most secretory cells showed scant secretory granules and blebbings. Dense bodies and fibrillary inclusions were seen in intermediate and basal cells. Styrene also caused alterations of cytoplasmic components in type II pneumocytes and bronchiolar cells as well as thickness of the alveolar wall. These abnormalities were accompanied by depletion of glutathione (GSH) in the lung tissue. Pneumotoxic effects of systemic administration of styrene were dose dependent and tended to be more severe than those seen in the animals exposed for longer periods to styrene by inhalation. Metabolic activation of styrene and subsequent cell damage induced by the reactive metabolite styrene oxide may be involved in the sequence of events culminating in the toxic insult to the respiratory tract.

Isolation and identification of Encephalitozoon hellem from an Italian AIDS patient with disseminated microsporidiosis.

Microsporidia are primitive mitochondria‐lacking spore‐forming eukaryotic protozoa that infect a wide variety of animals and also humans. Of the five genera (Encephalitozoon, Enterocytozoon, Septula, Nosema and Pleistophora) that cause infections in humans, Enterocytozoon bieneusi. Septula intestinulis, and Encephulitozoon hellem are being increasingly identified in patients with acquired immunodeficiency syndrome (AIDS). E. bieneusi causes gastrointestinal disease, S. intestinulis causes gastrointestinal and disseminated disease, and E. hellem causes ocular as well as disseminated disease. We have established in continuous culture a strain of microsporidia isolated from the urine and throat washings of an Italian AIDS patient and identified it as Encephalitozoon hellem, based on its ultrastructural morphology, antigenic pattern, and polymerase chain reaction‐amplified small subunit ribosomal RNA. We believe that this is the first time that a strain of microsporidia has been isolated from the throat washings of a patient with microsporidiosis.

Tetrahydrofolate dehydrogenase in blood cells and in hematopoietic organs of different vertebrate species

Some general aspects in cytochemical demonstration of the tetrahydrofolate dehydrogenase, concerning the final reaction product, are studied. Steady and variable factors are detected in a comparative study of Vertebrate hemopoiesis: the enzyme exhibits peculiar features in different cell types. The reactivity progressively decrease in the erythropoietic series, in concomitance with hemoglobin synthesis. Conversely an increase in the intensity of reaction is found in the granulocytopoietic series; the correspondence of positive material with the specific (eosinophil and heterophil) granulations can be discussed. The thrombocytopoietic series is also labelled by this reaction.

Cytochemical evidence for potassium-dependent p-nitrophenylphosphatase activity in pavement cells of Rana esculenta mesentery.

We previously reported that during hibernation in Rana esculenta, various organs (i.e., skin, urinary bladder, kidney) change their osmoregulatory activity. Here, we considered the possible role of the frog mesentery in the ion transport, evaluating morphological and cytochemical (K+‐p‐nitrophenylphosphatase activity) aspects.

Seasonal variations of K+‐p‐nitrophenyl phosphatase activity in the epidermis of the crested newt: A quantitative and ultrastructural study

Abstract The seasonal distribution of K+‐p‐nitrophenyl phosphatase, an enzyme involved in osmoregulation, was determined cytochemically in the skin of the crested newt. Microdensitometric measurements of the final reaction product of the enzyme showed a greater activity in the upper layers of the epidermis (except for the horny layer), and higher activities during the terrestrial phase (in the summer) compared to the aquatic phase (in the winter).

Cytochemical study of K+-dependent p-nitrophenyl-phosphatase activity in the urinary bladder of Salamandra salamandra.

The ultrastructural Na+-K+-ATPase localization in the salamander urinary bladder has been studied by the histochemical techniques of Ernst (1972) and Mayahara et al. (1980). Reaction products have been specially found on the basal and lateral membranes of granular and mitochondria-rich cells. The variable presence of artifacts, often accompanying Pb-capture phosphatase cytochemistry, is discussed. Additional data on the active ion transport have been obtained by using electrophysiological techniques.

Leucine aminopeptidase activity in blood and hemopoietic organs of different Vertebrates: A histochemical comparative study

Leucine aminopeptidase distribution was examined in the cells of peripheral blood and hemopioetic organs of different Vertebrate classes using histoenzymatic methods. Various degrees of staining intensity were observed in leukocytes of the distinct Vertebrates: in particular, leukocytes of fresh water Osteichthyes and Mammals looked strongly positive, whereas leukocytes of Amphibians, Reptiles, and Birds were barely reactive without great differences among species. The observations should be related to enzyme molecular structure and to kinetics and substrate specificity.