Regenerated middle ear mucosa after tympanoplasty. Part II. Scanning electron microscopy.

The ultrastructural appearance of the regenerated middle ear epithelium, found at the second operation of staged ICWT with mastoidectomy, has been investigated herein with the scanning electron microscope. The regenerated epithelium consists of flat nonciliated cells, "elevated" nonciliated cells with microvilli, and ciliated cells. Secretory material is present on the surface of the "elevated" nonciliated cells surrounding the ciliated ones. Regeneration of the mucosa occurs following precise topographic differences that mimic the distribution of epithelial cells in the normal middle ear. It is confirmed that a morphologically normal middle ear epithelium regenerates to cover all denuded bone surfaces within 12 months--after first stage ICWT with mastoidectomy--when silicone rubber sheeting has been used to maintain an aerated middle ear and mastoid space.

Molded tympanic heterografts. Histologic evaluation.

The histologic appearance of the molded tympanic heterograft developed at the ENT Clinic of the University of Parma, Italy, is investigated with light and electron microscopy. Evaluation of the graft before insertion disclosed a unique structure of interwoven collagen bundles. Examination of grafted tympanic membrane showed a structure closely resembling the normal human tympanic membrane. The fate of the heterologous material and the host reaction to it are discussed in relation to histologic findings.

Experimental respiratory cryptosporidiosis in immunosuppressed rats: a light and electron microscopy study.

Cryptosporidium parvum is a coccidian protozoon that causes diarrhoeal enteritis in immunocompetent and immunocompromised humans and other mammals. Sometimes, chiefly in HIV-infected subjects, anatomical sites other than gastro-intestinal tract, such as the biliary and respiratory tree, are involved. We performed an experimental respiratory infection in immunosuppressed albino rats with a C. parvum human-derived isolate, to confirm the possibility of a primary infection at this site and to evaluate the protozoan damages by light and also by transmission electron microscopy (TEM). The animals were infected intratracheally with 1 x 10(6) C. parvum oocysts/ml and, from the 7th day post-infection, biological specimens of trachea, bronchi, lung and ileum were zoopsied. A sole cryptosporidial colonization of the respiratory tract, from the trachea to the median bronchi, without lung parenchyma infection, was observed. Moreover 13/33 (39.4%) rats also developed intestinal infection. TEM study of the respiratory tree specimens demonstrated that cryptosporidia infect either ciliated or goblet cells, and confirmed the role of microvilli in the parasite cell adhesion. The most relevant alterations involved the ciliated cells, with loss of cilia and nuclear and cytoplasmic damages.

[Vancomycin and "red man's syndrome". Presentation of a clinical case]. / Vancomicina e "Red man's syndrome". Presentazione di un caso clinico.

This paper describes a case of "Red man's syndrome" in a patient with staphylococcal sepsis. The patient was initially treated with intravenous Vancomycin and afterwards with Teicoplanin. The adverse reaction appeared immediately after the start of pharmacological treatment.

Spiramycin treatment of Toxoplasma gondii infection in pregnant women impairs the production and the avidity maturation of T. gondii-specific immunoglobulin G antibodies.

The aim of the study was to evaluate the influence of treatment with spiramycin on the increase of immunoglobulin G (IgG) titers and IgG avidity indexes (AI) in pregnant women with seroconversion from the beginning of therapy until delivery and after delivery. This group was compared with adult patients with recently acquired untreated toxoplasmosis. One hundred four samples from 32 pregnant women with seroconversion for toxoplasmosis and/or very low IgG AI were followed from the beginning of therapy with spiramycin until delivery. Twenty-nine women were further followed some months after delivery and interruption of therapy. Thirty-eight samples from 16 untreated, nonpregnant patients were evaluated as the control group. The Toxoplasma gondii-specific IgG antibody and the T. gondii-specific IgG AI were significantly delayed in pregnant women receiving therapy compared to nonpregnant, untreated controls, and the findings were consistent with the results of assays from two different manufacturers. The T. gondii-specific IgG AI increased in pregnant women after they gave birth. Avidity maturation is delayed during pregnancy and treatment, and low-avidity antibodies in pregnant women within 3 to 4 months cannot be taken as a sign of infection.

[Paracoronal cavity system and papillary water uptake]. / Sistema cavitario paracoronale e richiamo idrico papillare.

In the research it has been carried out a morphological investigation of the paracoronal area of the fungiform papillae. By means of scanning, transmission and light microscopy it has been observed in this area a series of superficial openings around and external to the ciliary crown; and in the epithelium corresponding cavitary system. Each cavity on the other hand appears surrounded by extremely narrow epithelial cells and thus appears able to facilitate the papillary exchange activity. This paracoronal cavitary system is proposed as morphological candidate for the conspicuous water entry in the papillae during osmotic phenomena.

Prevalence of chlamydial antibody in pregnancy. A matched-pair study.

In this matched-pair study 139 pregnant women were matched on the basis of age to an equal number of non-pregnant women with no signs of genital infection. The mean age was 28.7 years (range 20-41). The cut-offs used for detection of chlamydial antibody were 1:64 and 1:128 for IgG and 1:16 for IgA. IgG antibody at 64 was detected in 37.4% of pregnant women, compared to 46% of controls (p = 0.145). There was, however, a statistically significant difference between the groups for IgG at 128 (gravidae = 15.8%; controls = 28%; p = 0.014). IgA were detected in 8.6% and 16.5% of subjects, respectively (p = 0.047). IgG levels did not vary with increasing age among the pregnant women, but rose significantly with age in non-pregnant controls (logistic regression p-values = 0.011 and 0.006, for IgG at 64 and 128, respectively). IgG-positive women in the control group tended to be older than pregnant IgG-positive women (p = 0.06). These differences could not be explained by marital status, parity or use of oral contraceptives. In view of the lack of epidemiological differences, biological explanations might be invoked.

Kinetics of IgM and IgG antibodies in mice experimentally infected with cystogenic strain of Toxoplasma gondii.

Mice were infected with a "cystogenic" strain of T. gondii and sera obtained at different times were tested using DT and IFAT (cell wall antibodies tests) and IHAT (performed with extractive cytoplasmic antigen). We found different kinetics of DT- and IFAT- versus IHAT-titers: IHAT is negative during the early phase of the experimental infection when DT and IgM-IFAT are already positive. Furthermore IgM antibodies were never found against cytoplasmic antigens by the IHAT method. At weekly intervals after the experimental infection a biological test was also performed using samples of different organs. We found that one week after the infection only the brain was constantly positive in the biological test. The antibody pattern was similar in every positive test irrespective of the source and size of the material used for the inoculum. These data suggest that the result of a biological test may be available earlier (already after 7 days) if a test for antibodies against cell wall antigens is performed on the IgM fraction of the mouse serum.

Ultrastructural features of spindle microtubule organization during the nuclear division of Encephalitozoon hellem.

Ultrastructural studies were carried out to describe the nuclear division cycle of a strain of Encephalitozoon hellem isolated from an Italian AIDS patient. The nuclear division occurs during the proliferative vegetative phase and it is characterized by the intranuclear mitosis and by the lack of centrioles. The spindle termini are electron dense spindle plaques (ESPs), resembling to the spindle pole bodies (SPBs) of Saccharomycetes. The ESPs are bifacial organella forming microtubules on both nucleoplasic and cytoplasmic faces. In the outer layer of the spindle plaque are present vesicular elements lined by a double membrane of unknown function. The peculiar morphological features of E. hellem ESPs indicate that both intranuclear spindle and cytoplasmic microtubules are involved in the nuclear division.

Morphological, cytochemical and ultrastructural studies of a case of systemic mastocytosis.

Morphological, cytochemical and ultrastructural studies of mast cells were carried out in a patient affected with systemic mastocytosis. Neoplastic mast cells showed morphological features between classic tissue mast cells and circulating basophils. They showed strong granule metachromasia after toluidine blue, faint positivity to Hotchkiss reaction, strong positivity to chloroacetate esterase, while they were negative to alkaline phosphatase. Ultrastructural observations showed heterogeneity of granules, most of which had homogenous fine dotted contents. The origin and linkage between mast cells and circulating basophils are discussed.

Human immunodeficiency virus (HIV): an ultrastructural study.

H-9 cells producing HIV were examined by electron microscopy to value the virus-host cell relationships. HIV fine structure was also studied. HIV induces little cellular damages and it can penetrate into the cytoplasm by phagocytosis. Phagocytosis of the virus could play an important role in the mechanism of cellular infection.

[Clinical and therapeutic profile of 3 cases of cryptococcal meningitis in patients with AIDS]. / Rilievi clinici e terapeutici su tre casi di meningite criptococcica in pazienti con AIDS.

We report three cases of cryptococcal meningitis in patients with AIDS observed in our Institution. In addition, we discuss antifungal treatment during and after the acute phase of the disease and the use of fluconazole as a prophylactic treatment of disease relapse.

Human cytomegalovirus replicates abortively in polymorphonuclear leukocytes after transfer from infected endothelial cells via transient microfusion events.

Using a recently developed model for in vitro generation of pp65-positive polymorphonuclear leukocytes (PMNLs), we demonstrated that PMNLs from immunocompetent subjects may harbor both infectious human cytomegalovirus (HCMV) and viral products (pp65, p72, DNA, and immediate-early [IE] and pp67 late mRNAs) as early as 60 min after coculture with human umbilical vein endothelial cells (HUVEC) or human embryonic lung fibroblasts (HELF) infected with a clinical HCMV isolate (VR6110) or other wild-type strains. The number of PMNLs positive for each viral parameter increased with coculture time. Using HELF infected with laboratory-adapted HCMV strains, only very small amounts of viral DNA and IE and late mRNAs were detected in PMNLs. A cellular mRNA, the vascular cell adhesion molecule-1 mRNA, which is abundantly present in both infected and uninfected HUVEC, was detected in much larger amounts in PMNLs cocultured with VR6110-infected cells than in controls. Coculture of PMNLs with VR6110-infected permissive cells in the presence or absence of RNA, protein, and viral DNA synthesis inhibitors showed that only IE genes were transcribed in PMNLs during coculture. Synthesis of IE transcripts in PMNLs was also supported by the finding that only the copy number of IE mRNA (and not the DNA or the pp67 mRNA) per infected PMNL increased markedly with time, and the pp67 to IE mRNA copy number ratio changed from greater than 10 in infected HUVEC to less than 1 in cocultured PMNLs. Fluorescent probe transfer experiments and electron microscopy studies indicated that transfer of infectious virus and viral products from infected cells to PMNLs is likely to be mediated by microfusion events induced by wild-type strains only. In addition, HCMV pp65 and p72 were both shown to localize in the nucleus of the same PMNLs by double immunostaining. Two different mechanisms may explain the virus presence in PMNLs: (i) one major mechanism consists of transitory microfusion events (induced by wild-type strains only) of HUVEC or HELF and PMNLs with transfer of viable virus and biologically active viral material to PMNLs; and (ii) one minor mechanism, i.e., endocytosis, occurs with both wild-type and laboratory strains and leads to the acquisition of very small amounts of viral nucleic acids. In conclusion, HCMV replicates abortively in PMNLs, and wild-type strains and their products (as well as cellular metabolites and fluorescent dyes) are transferred to PMNLs, thus providing evidence for a potential mechanism of HCMV dissemination in vivo.

Intracellular killing of Brucella melitensis within mouse peritoneal macrophages: influence of treatment with rifampicin. An ultrastructural study.

The aggregation and condensation of ribosomes and the disjunction of the cell-wall membranous system are the ultrastructural alterations caused by rifampicin on B. melitensis cultured in Brucella-Broth medium. Our ultrastructural researches carried out on mouse peritoneal macrophages infected with B. melitensis and treated with rifampicin (1 microgram/ml) have demonstrated that vacuoles containing B. melitensis which had been damaged by the drug fuse with lysosomes. On the contrary vacuoles containing undamaged and viable Brucellae showed markedly impaired lysosomal fusion.

Toxoplasma gondii: in vivo and in vitro immunological and ultrastructural patterns of a human low virulent strain.

The AA. analyze the ultrastructural and immunological patterns of a low virulent strain of T. gondii cultured in vitro on A-9 cells line (PV-H1C-83). The tissue culture method described here is highly recommended to study the immunological aspects of experimental toxoplasmosis. Biological tests' results and the time courses of serological tests are also similar to those obtained from mice infected with cerebral tissue containing cysts. The low virulent strain (PV-H1C-83), when cultured in vitro, is able to induce the formation of large parasitophorous vacuoles, in which the EM investigation shows a typical cyst wall enveloping numerous bradyzoites.

Alterations due to ampicillin and rifampicin in S. sanguis and S. aureus isolated from dental plaque. An electron microscopic study.

In this work we analysed the ultrastructural changes in S. aureus and S. sanguis after exposure to rifampicin and ampicillin respectively. S. aureus grown in the presence of rifampicin showed ultrastructural changes that can be summarized as follows: the peripheral cell-wall increased to three to five times the normal thickness; the cross-walls were considerably (two to ten times) thicker than normal; after 8 h of exposure a complete lysis occurred. S. sanguis grown in the presence of ampicillin showed ultrastructural changes that can be summarized as follows: aggregation and condensation of ribosomes; alterations of division with the presence of asynchronous septa; in some bacterial cells a prominent bulge was observed at one pole of the cell; after 8 h of exposure a complete lysis occurred.

Mechanisms of microsporidial cell division: ultrastructural study on Encephalitozoon hellem.

The mitotic process in microsporidian Encephalitozoon hellem, a known human pathogen, has been studied with the aim of elucidating some ultrastructural aspects of its nuclear division. The presence of a nuclear spindle, of "electrondense spindle plaques" associated with the nuclear envelope and of cytoplasmic double walled vesicles are reported. We suggest that these "electrondense spindle plaques" serve as foci for intranuclear and cytoplasmic microtubule arrangements, similar to the microtubule organizing centers within the centrosomes of animal cells. The extent to which the microsporidial division process is comparable with that of more familiar eukaryotes such as yeast cells is discussed.

Life cycle of P. carinii in the lung of immuno-compromised hosts: an ultrastructural study.

We describe the ultrastructural features of interstitial pneumonia and life cycle of P. carinii in the lung of immuno-compromised hosts. The hyperplasia and edema of alveolar lining cells appear to be largely responsible for the extensive desquamative alveolitis which characterizes the histopathologic features of P. carinii in the lung of immuno-compromised hosts. The ultrastructural data concerning the ameboid trophozoite, particularly the presence of lobopodies and the reduplication by binary fission, associated with cyst forming capacity, suggest that P. carinii can be reasonably placed within the Protozoa.

The morphogenesis of BLV (bovine leukemia virus) cultivated on FLK (fetal lamb kidney): an ultrastructural study.

A new cell line, obtained by co-cultivation of fetal lamb kidney cells and lymphocytes collected from an adult calf affected by enzootic bovine leukemia, was studied for bovine leukemia virus (BLV) morphogenesis. In this new cell line, called FLK-BLV, persistently infected with BLV, we identified extracellular and intracellular BLV particles. We never observed "budding" particles along the cell surface, and therefore assumed it was a new BLV maturation process in the cell vacuoles. In fact we found mature and non-mature particles connected with the cell-membrane system or cellular debris within vacuoles. We suggest that the viral envelope could be supplied by vacuole membrane. In our samples we also observed a cytopathic effect with syncytia formations similar to those observed on other BLV-producing cell lines.

Effect of teicoplanin and vancomycin on Staphylococcus aureus ultrastructure.

Morphological changes induced by teicoplanin and vancomycin on Staphylococcus aureus have been comparatively evaluated. The most pronounced structural damages were found on the cell wall which was uniformly thickened on bacteria exposed to teicoplanin while it was of irregular thickness and often absent around the cells in those exposed to vancomycin. The inhibitory action of teicoplanin on proteoglycan polymerization but not on nucleic acid and protein synthesis indicates that the effect in the wall is due to the accumulation at this level of proteoglycan soluble precursors continuously produced by the cell. The different effects induced by vancomycin on cell wall morphology can also be related to the compatibility of this antibiotic in altering cytoplasmatic membrane function and ribonucleic acid synthesis.