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Biomedical subjects

M Margiotta

Publications and source records attributed to M Margiotta.

35 records · Page 2Linked to original sources
PubMed1994

HIV-1 nucleic acids localize to the spermatogonia and their progeny. A study by polymerase chain reaction in situ hybridization.

The purpose of this study was to determine the histological distribution of in situ polymerase chain reaction (PCR)-amplified HIV-1 nucleic acids in the male genital tract to elucidate the mechanism of sexual transmission of AIDS. Viral DNA was detected in the testicular tissue of 11 of 12 men with HIV-1 infection using the PCR in situ hybridization technique. The amplified viral DNA localized to many spermatogonia, spermatocytes, and rare spermatids. Relatively few viral infected macrophages were noted, mostly in the prostate. The viral infection was activated given the presence of cDNA sequences consistent with genomic and multiple spliced transcripts as determined by reverse transcription in situ PCR. PCR-amplified viral nucleic acids were not detected in the epithelial of the prostate, epididymis, seminal vesicles, or penis in men with AIDS nor in any genital tract tissues from three boys who died of AIDS acquired in utero. The demonstration that HIV-1 selectively infects the spermatogonia and their progeny suggests that this may serve as a primary source of venereal spread of the virus. Concomitant destruction of these cells by HIV-1 may also explain the marked inhibition of spermatogenesis and severe atrophy that characterizes the testes in AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Histological distribution of polymerase chain reaction--amplified human papillomavirus 6 and 11 DNA in penile lesions.

The purpose of this study was to ascertain the histological pattern of distribution of human papillomavirus (HPV) 6 and 11 DNA in penile lesions by in situ hybridization after amplification by the polymerase chain reaction (PCR). HPV DNA was routinely detected by in situ hybridization with or without PCR amplification in granular layer cells that showed perinuclear halos and nuclear atypia. Cells that lack these histological features rarely exhibited HPV DNA with conventional in situ hybridization. However, after PCR amplification, in situ analysis showed that many of the cells that lacked halos and atypia contained HPV DNA. The hybridization signal often localized to crevices in the epithelium where there was relative hyperkeratosis and a thickened granular layer. HPV DNA was not noted in the basal cells and was rarely identified in other parts of the lesion. It is concluded that penile tissues may contain HPV DNA when lacking the diagnostic features of a condyloma/low-grade intraepithelial lesions and that such tissues usually demonstrate specific histological changes characterized by a focally thickened granular layer often associated with epithelial crevices.

Biopsy↗
PubMed1992

In situ localization of PCR-amplified human and viral cDNAs.

We describe a technique, called reverse transcriptase (RT) in situ PCR, whereby RNA may be nonisotopically detected in fixed cells when amplified by PCR after cDNA synthesis by RT. RT in situ PCR using primers specific for the measles virus generated an intense signal in most measles-infected HeLa cells, as compared to the weak signal generated in few cells using standard in situ hybridization analysis. The viral RNA that localized to the nucleus spared the nucleoli, was most evident when the RT step used the primer complementary to the negative genomic strand, and was demonstrated in all multinucleated cells and the majority of uninucleate cells. A hybridization signal was evident with standard RNA in situ hybridization using the human megakaryocyte cell line Dami and a probe for glycoprotein IIB (GIIB) mRNA but not a probe for amyloid precursor protein (APP) or gelsolin (GEL) mRNA. After RT in situ PCR, signals were evident for each target localizing to the nucleolus for APP and to perinucleolar and cytoplasmic locations for GEL and GIIB. The latter findings suggest that mRNAs may follow different geographic pathways as they progress from premessage to transcriptionally active message.

Base Sequence↗
PubMed1992

Rapid in situ detection of PCR-amplified HIV-1 DNA.

The low copy number of human immunodeficiency virus 1 (HIV-1) DNA infected cells precludes routine detection by in situ hybridization. The inability to detect cells latently infected by HIV-1 makes difficult the study of factors that induce viral transcription, an essential factor in the development of the acquired immune deficiency syndrome (AIDS). A sensitive and rapid technique to detect HIV-1 DNA could be used as a diagnostic test for AIDS and to differentiate latent versus active viral infection. We describe a 3-h technique whereby HIV-1 DNA is amplified by hot start polymerase chain reaction (PCR) and detected directly in infected cells. The specificity of the assay was demonstrated by double labeling the positive cells with CD4. Using a CR10 HIV-1-infected cell line, the 90% of cells that were HIV-1 DNA positive could be distinguished from the 10% that were actively expressing HIV-1 RNA. The PCR in situ technique should allow for the direct localization of DNA sequences in cells that would otherwise be undetectable by conventional in situ analysis.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Diazepam effects on frog skin cyclic nucleotide phosphodiesterase.

1. The activities of cAMP phosphodiesterases (cAMP-PDE) have been measured in the homogenate of the skin of Rana esculenta. 2. The tissue possesses two distinct enzymes: a "low" Km PDE (Km = 0.42 x 10(-6) M; Vmax = 16 pmol/mg protein/min) and a "high" Km PDE (Km = 180 x 10(-6) M; Vmax = 2853 pmol/mg prot/min). Only the "high" Km form is stimulated by calcium. 3. Diazepam (1-0.5 mM) significantly inhibits both enzymes, the inhibition being of competitive type.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1989

Sensitivity and detection efficiency of the peroxidase antiperoxidase (PAP), avidin-biotin peroxidase complex (ABC), and peroxidase-labeled avidin-biotin (LAB) methods.

The authors have examined the sensitivity and detection efficiency of the three peroxidase methods that currently have the widest application in diagnostic immunohistochemistry: the peroxidase-antiperoxidase (PAP), the avidin-biotin complex (ABC), and the labeled avidin-biotin (LAB) methods. Sensitivity was evaluated by determining the highest useful dilution of polyclonal antiglucagon antibodies applied to formalin-fixed, paraffin-embedded human pancreas. Detection efficiency was evaluated by tabulation of the total number of positive (three or more positive cells) islets. On direct comparison, the LAB method exceeded the PAP and ABC methods in both sensitivity and detection efficiency, which were essentially equal. Titration of linking antiserum of the PAP method boosted its sensitivity and detection efficiency above that of ABC; the PAP had equal sensitivity to the LAB and exceeded it in detection efficiency. The authors conclude that comparisons of immunohistologic methods are meaningful only if both sensitivity and efficiency are considered along with the unique requirements of any single method.

Avidin↗
PubMed1987

Action of forskolin on non-electrolyte permeability across the frog skin as compared to that of vasopressin and isoprenaline.

Forskolin, a natural diterpene activating the adenyl cyclase in a receptor-independent manner, increases symmetrically both transepithelial fluxes of urea and erithrytol through the frog skin. The effect is dose-dependent, being 5 X 10(-6) M the dose necessary to obtain the maximal action. Forskolin-induced permeabilization is inversely proportional to the molecular weight of water soluble molecules (urea greater than erythritol greater than mannitol); also the permeability of a mainly lipid soluble molecule, i.e. antipyrine, is slightly increased by the diterpene. The permeability pattern is more similar to that induced by isoprenaline as compared to that elicited by vasopressin. Differently from what occurs in other tissues, small doses of forskolin (10(-8) M) are unable to potentiate the actions of vasopressin and isoprenaline on urea permeability across the frog skin. Moreover, the maximal action of forskolin is not additive with the maximal ones of isoprenaline and vasopressin.

Animals↗
PubMedDate not supplied

The augmenter of liver regeneration induces mitochondrial gene expression in rat liver and enhances oxidative phosphorylation capacity of liver mitochondria.

BACKGROUND: The mammalian augmenter of liver regeneration gene encodes a protein involved in the unique process of liver regeneration. The augmenter of liver regeneration respective protein stimulates hepatocyte proliferation in hepatectomized rats and inhibits cytotoxic activity of liver-derived Natural Killer cells from intact rats. Augmenter of liver regeneration protein shares homology with a Saccharomyces Cerevisiae protein essential for the viability, oxidative phosphorylation and cell-division cycle. AIMS: To demonstrate if augmenter of liver regeneration protein, like the homologous in the yeast, plays a role in the regulation of biogenesis of mitochondria. METHODS: Augmenter of liver regeneration protein was injected in intact rats and, in the hepatic tissue, the expression of two genes located in two different regions of the mitochondrial genome, mitochondrial ATPase 6/8, and ND1 subunit, and of a nuclear gene, mitochondrial Transcription Factor A, were considered. In addition, cytochrome content and oxidative phosphorylation capacity of liver-derived mitochondria were evaluated. RESULTS: The augmenter of liver regeneration protein administration induces an increase in the mitochondrial gene expression and enhances cytochrome content and oxidative phosphorylation capacity of liver-derived mitochondria. CONCLUSIONS: The present data demonstrate a comparable role in the regulation of mitochondria biogenesis in the eukaryotic cell like the yeast protein. This phenomenon could be part of the complex mechanism through which augmenter of liver regeneration regulates hepatocyte proliferation.

Adenosine Triphosphatases↗
PubMedDate not supplied

[In vitro mucociliary clearance: observations in subjects exposed to acute inhalation of nitrous vapors].

Acute inhalation of nitrous vapours did not cause any damage to the respiratory apparatus detectable via spirometric or X-ray tests in the four workers who were actually exposed and kept under observation during the two months following the explosion of a tank containing nitric acid. However, measurement of the coefficient of relative transport speed in vitro of tracheo-bronchial secretions revealed alterations of the mucus related to specific situations, such as during acute inhalation of nitrous vapours and upon resuming work. The coefficient of relative speed, obtained with the in vitro technique on the palate of the frog, thus proved to be reliable in monitoring irritation of the mucus secreting apparatus of workers accidentally exposed to acute inhalation of nitrous vapours.

Adult↗
PubMedDate not supplied

[The inhalation of low concentrations of manganese powders produces changes in respiratory mucociliary clearance].

The aim of this study is to verify whether inhaling metallic dusts, containing a lower concentration of Mn (as Mn3O4) than current TLV can cause alterations in exposed workers tracheobronchial mucociliary clearance. We studied 20 grinders using an 11.5-13% Mn steel, and a control group of 21 standard steel grinders, employed in the same foundry. Environmental Mn dust was measured by personal samplers. All workers were administered a questionnaire about chronic bronchitis; the following examinations were also carried out: medical examination, spirometry, chest standard X-ray and urinary Mn dosage. Mucociliary clearance was measured by human respiratory mucus transportability on frog palate and expressed as normalized frog palate transport rate (NFPTR). Mucus was obtained through a sputum so protected as to avoid salivary contamination. Environmental measurements showed a Mn concentration from 0.1 to 1 mg/m3 with respect to a TLV of 5 mg/m3. Exposed workers and control group were homogeneous as far as age, working period, tobacco smoking habit and spirometric parameters are concerned. Chest X-ray examination showed no evidence of pneumoconiosis. Mn exposed workers showed a NFPTR reduction, if compared to normal level (0.70). NFPTR average value in exposed group has come out to be much lower than in control group. NFPTR alteration in Mn exposed group appears to be strictly linked to a longer than 15 years working seniority. Urinary Mn values resulted extremely low in each worker and their average was not significantly different between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Mucociliary clearance and respiratory function in foundry workers].

The aim of the study was to establish whether changes occur in respiratory function, particularly mucociliary clearance, among second fusion smeltery workers. The research covered 93 male smelters employed in steel forming and casting and 116 male workers of an electric power station, considered as non-exposed. Physiological, pathological and occupational histories of all subjects under study were available. An ECCS respiratory symptoms questionnaire was administered to all subjects ad the two groups also underwent a general medical examination, a spirometry and a chest X-ray. During the medical examination sputum was collected from the subjects to measure mucus transport rate on frog palate, expressed as Normalised Frog Palate Transport Rate (NFPTR). For the environmental research, dust, fumes and gas samplings were taken either at a fixed station or by means of personal dosimeters. Environmental research revealed very low concentrations of respiratory irritants (total dust: 0.2-6.8 mg/m3; respirable dust: 0.1-4.9 mg/m3; total silica: < 2-15.5%; respirable silica: < 0.004-0.3 mg/m3; iron: 0.008-0.085 mg/m3; chromium and manganese: < 0.001 mg/m3; fumes and gases: well below the TLV. The two groups were homogeneous with regard to age and smoking habits. Exposed workers showed rales, dyspnoea and spontaneous phlegm more frequently than non-exposed workers. NFPTR alterations were checked in 49 out of 81 exposed and in 18 out of 81 non-exposed subjects (chi squared = 22.9; p < 0.001). Stratification of the results according to smoking habits further confirmed the strong association between occupational exposure and NFPTR alterations. Smelters showed significantly lower mean NFPTR values compared to non-exposed subjects; also, the mean value of NFPTR in the exposed was below 0.70, which is considered the lowest individual limit in normal subjects. The only variable which explains a large part of the variability of NFPTR is past work in a smeltery rather than in an electric power station. The spirometries showed that only the mean PEF values were significantly lower among the exposed. Stratified analysis of the results according to smoking habits in the two groups revealed a close association between smeltery work and reduction of PEF to under 80% of the ECCS 1983 theoretical values, independently of smoking habits. We also compared the mean PEF values, both as measured values and as percent values of the ECCS 1983 theoretical values, stratified for occupational exposure and smoking; the results again showed that differences between these mean values were mainly due to current or past work in the foundry.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMedDate not supplied

Respiratory mucus transportability is impaired in foundry workers: a longitudinal study.

Mucus transportability impairment can prolong the permanence of occupational inhalable noxae within ciliated airways. A reliable, non-invasive indicator of mucus transportability is the Normalized Frog Palate Transport Rate (NFPTR). The aim of this 3-year prospective study was to compare NFPTR between a group of 166 foundry workers (E) and a group of 133 power plant workers (NE). In the first and third years of the study, workers underwent: clinical examination, spirometry, NFPTR, chest radiography. In both plants, environmental concentrations of respiratory irritants were well below the limits set by the American Conference of Governmental Industrial Hygienists. Both groups were homogeneous for age and smoking habits. Mean NFPTR was significantly lower in E than in NE in the first and third years of the study, and in smokers in comparison with non-smokers, at the end of the follow-up. NFPTR impairment was significantly associated with occupational exposure in the first and third years of the study. In the third year, a decline in NFPTR was associated with exposure, smoking habits, FVC and FEV1/FVC.100. At the end of the study, the means of FVC, FEV1 and PEF were significantly lower in E. No cases of pneumoconiosis were observed. In this study, low doses of foundry respiratory irritants were associated with impairment of mucus transportability; the consequent slowing of mucociliary clearance increased internal doses of foundry airborne noxae.

Adult↗