Usefulness of Ifn-Gamma Release Assays in Clinical Management of Difficult TB Cases: Evidence from Clinical Practice

Performance of T-SPOT.TB™ (TS-TB) and QuantiFERON TB Gold- In tube (QFT-IT) assays was evaluated for detection of M. tuberculosis (Mtb) infection in patients with suspected extra-pulmonary or smear-negative pulmonary tuberculosis (TB) in a low prevalence country. Twenty-one out of 35 patients were affected by active TB. Mtb culture isolation was achieved in 76% of cases. Tuberculin skin testing (TST), TS-TB, and QFT-IT yielded a positive result in 67%, 95% and 81% of cases, respectively. Agreement of interferon-γ release assays and TST was 70% (κ=0.18 for TS-TB; κ=0.46 for QFT-IT). Increased sensitivity of blood assays (>80%) improved diagnostic evaluation of difficult TB cases.

IFN-gamma release assays in tuberculosis management in selected high-risk populations

Tuberculosis (TB) is the most deadly infectious disease in the world. TB control relies on passive case findings and targeted treatment of latently infected individuals at high risk of disease progression. Tuberculin skin testing (TST) is conventionally used for detection of TB infection. Recently, blood assays measuring the release of IFN-gamma by TB-specific effector memory T cells have been developed to overcome TST limitations. Overall, IFN-gamma release assays are more specific than TST, more sensitive in detecting active TB and correlate better with TB exposure in immune-competent patients, at least in low-burden settings. There are three US FDA-approved assays commercially available: the ELISpot-based assay T-SPOT.TB (Oxford Immunotech, UK) and two ELISA-based formats, QuantiFERON TB Gold (QFT) and QFT-in tube (Cellestis, Australia). Recent international guidelines and consensus statements recommend the use of IFN-gamma release assays at different levels in TB management. However, conclusive evidence-based information targeting populations at high TB risk, including HIV-infected individuals, children and patient candidates for biotherapy with TNF-alpha blockers, are lacking. The aim of this review is to focus our attention on studies addressing the performance of commercial IFN-gamma release assays in clinical management of TB infection in these highly selected settings to provide a more comprehensive picture of the actual scenario and to identify areas to be investigated further.

Analysis of Mycobacterium tuberculosis-specific CD8 T-cells in patients with active tuberculosis and in individuals with latent infection

CD8 T-cells contribute to control of Mycobacterium tuberculosis infection, but little is known about the quality of the CD8 T-cell response in subjects with latent infection and in patients with active tuberculosis disease. CD8 T-cells recognizing epitopes from 6 different proteins of Mycobacterium tuberculosis were detected by tetramer staining. Intracellular cytokines staining for specific production of IFN-γ and IL-2 was performed, complemented by phenotyping of memory markers on antigen-specific CD8 T-cells. The ex-vivo frequencies of tetramer-specific CD8 T-cells in tuberculous patients before therapy were lower than in subjects with latent infection, but increased at four months after therapy to comparable percentages detected in subjects with latent infection. The majority of CD8 T-cells from subjects with latent infection expressed a terminally-differentiated phenotype (CD45RA⁺CCR7⁻). In contrast, tuberculous patients had only 35% of antigen-specific CD8 T-cells expressing this phenotype, while containing higher proportions of cells with an effector memory- and a central memory-like phenotype, and which did not change significantly after therapy. CD8 T-cells from subjects with latent infection showed a codominance of IL-2⁺/IFN-γ⁺ and IL-2⁻/IFN-γ⁺ T-cell populations; interestingly, only the IL-2⁺/IFN-γ⁺ population was reduced or absent in tuberculous patients, highly suggestive of a restricted functional profile of Mycobacterium tuberculosis-specific CD8 T-cells during active disease. These results suggest distinct Mycobacterium tuberculosis specific CD8 T-cell phenotypic and functional signatures between subjects which control infection (subjects with latent infection) and those who do not (patients with active disease).

Induced sputum as a tool for early detection of airway inflammation in connective diseases-related lung involvement

BACKGROUND

Induced sputum (IS) sampling is a safe and validated approach to study bronchial inflammation in chronic obstructive lung diseases. Although promising results have also been reported in various diffuse interstitial lung disorders, the potential use of IS in the assessment of connective tissue diseases (CTD)-related lung involvement has not yet been investigated.

AIM OF THE STUDY

To evaluate the clinical usefulness of IS in the early management of patients suffering from rheumatoid arthritis (RA) and systemic sclerosis (SSc) at the onset of respiratory symptoms.

PATIENTS AND METHODS

The study population included 19 patients (RA=12; SSc=7) and 14 age- and sex-matched healthy volunteers. Lung function testing, high resolution computed tomography (HRCT) of the thorax and IS collection were performed in all cases. Broncho-alveolar lavage (BAL) was obtained in selected patients.

RESULTS

IS samples from patients contained a significantly higher percentage of neutrophils and a lower percentage of macrophages compared to healthy subjects (p=0.002 and 0.001, respectively), while the total cell number showed no differences. In addition, sputa yielded both higher cell counts and higher neutrophils than BAL samples (p=0.02 in all instances). No correlations were found between IS findings and lung function parameters, HRCT and BAL findings.

CONCLUSIONS

This is the first study investigating the inflammatory cell pattern in IS from CTD patients with early clinical evidence of lung involvement. Future studies are needed to determine whether the assessment of airway inflammation adds significant information that may result in a relevant improvement of disease management.

Site specific phosphorylation of cytochrome c oxidase subunits I, IVi1 and Vb in rabbit hearts subjected to ischemia/reperfusion

We have mapped the sites of ischemia/reperfusion-induced phosphorylation of cytochrome c oxidase (CcO) subunits in rabbit hearts by using a combination of Blue Native gel/Tricine gel electrophoresis and nano-LC-MS/MS approaches. We used precursor ion scanning combined with neutral loss scanning and found that mature CcO subunit I was phosphorylated at tandem Ser115/Ser116 positions, subunit IVi1 at Thr52 and subunit Vb at Ser40. These sites are highly conserved in mammalian species. Molecular modeling suggests that phosphorylation sites of subunit I face the inter membrane space while those of subunits IVi1 and Vb face the matrix side.

beta1-Adrenoreceptor activation contributes to ischemia-reperfusion damage as well as playing a role in ischemic preconditioning

Protein kinase A (PKA) activation has been implicated in early-phase ischemic preconditioning. We recently found that during ischemia PKA activation causes inactivation of cytochrome-c oxidase (CcO) and contributes to myocardial damage due to ischemia-reperfusion. It may be that beta-adrenergic stimulation during ischemia via endogenous catecholamine release activates PKA. Thus beta-adrenergic stimulation may mediate both myocardial protection and damage during ischemia. The present studies were designed to determine the role of the beta(1)-adrenergic receptor (beta(1)-AR) in myocardial ischemic damage and ischemic preconditioning. Langendorff-perfused rabbit hearts underwent 30-min ischemia by anterior coronary artery ligation followed by 2-h reperfusion. Occlusion-reperfusion damage was evaluated by delineating the nonperfused volume of myocardium at risk and volume of myocardial necrosis after 2-h reperfusion. In some hearts ischemic preconditioning was accomplished by two 5-min episodes of global low-flow ischemia separated by 10 min before coronary occlusion-reperfusion. Orthogonal electrocardiograms were recorded, and coronary flow was monitored by a drip count. Three hearts from each experimental group were used to determine mitochondrial CcO and aconitase activities. Two-hour reperfusion after occlusion caused an additional decrease in CcO activity vs. that after 30-min occlusion alone. Blocking the beta(1)-AR during occlusion-reperfusion reversed CcO activity depression and preserved myocardium at risk for necrosis. Similarly, mitochondrial aconitase activity exhibited a parallel response after occlusion-reperfusion as well as for the other interventions. Furthermore, classic ischemic preconditioning had no effect on CcO depression. However, blocking the beta(1)-AR during preconditioning eliminated the cardioprotection. If the beta(1)-AR was blocked after preconditioning, the myocardium was preserved. Interestingly, in both of the latter cases the depression in CcO activity was reversed. Thus the beta(1)-AR plays a dual role in myocardial ischemic damage. Our findings may lead to therapeutic strategies for preserving myocardium at risk for infarction, especially in coronary reperfusion intervention.

New insights on the perturbations of T cell cycle during HIV infection

The role of the Human Immunodeficiency Virus (HIV) in the pathogenesis of the Acquired Immune-Deficiency Syndrome (AIDS) is changed. Direct HIV-mediated killing of CD4(+) T cells is not the only mechanism leading to lymphocyte depletion. There is increasing evidence that, during the chronic phases of infection, T cell activation, accelerated cell turnover, and cytokines imbalance induce the so-called cell cycle dysregulation (CCD). CCD is a recently discovered immune-pathogenic mechanism that mainly induces the depletion of both CD4(+) and CD8(+) uninfected T cells. It is due to a significant perturbation of protein metabolism as ubiquitin pathway defects of protein degradation are associated with an increased and unscheduled expression of cyclin B and p34 cdc kinase. Moreover, significant changes in the nucleolar structure and post-translational regulation of nucleolin have also been described. As modulation of CCD by anti-retroviral and immune-therapies has been suggested to predict a good immunological response in HIV-infected patients, a better understanding of such a mechanism is needed in order to further clarify its role in the pathogenesis and progression of HIV infection.

Role of mycobacteria-induced monocyte/macrophage apoptosis in the pathogenesis of human tuberculosis

Apoptosis is a physiological programmed cell death process whose dysregulation plays an important role in different human infectious diseases. An increasing number of intracellular pathogens are known to induce target cell apoptosis, while some other parasites inhibit it. Unlike necrosis, apoptosis is a silent immunological event occurring without inflammation. Infection-induced target cell apoptosis may be a successful strategy to eliminate pathogens and assure host survival. Conversely, apoptosis inhibition could represent an adaptive mechanism for pathogen survival, while it may be beneficial for the host to initiate an effective immune response. The worldwide increase in tuberculosis has stimulated more research aimed at defining the interaction between Mycobacterium tuberculosis and the immune system. M. tuberculosis possesses sophisticated strategies to circumvent its fate within target monocytic cells. Apoptosis of alveolar macrophages and monocytes has been described as a consequence of M. tuberculosis infection. Moreover, the observation that mycobacterial lipoproteins activate macrophages through Toll-like receptor (TLR) 2 suggests that innate immune receptors contribute to defence against M. tuberculosis. There is evidence that TLR-induced apoptosis modulates inflammation and immune activation during M. tuberculosis infection. Finally, the role of apoptotic-infected cells as a source of microbial antigens for cross-priming of effector T-cells is also discussed.

Induction of Apoptosis and Release of Interleukin‐1β by Cell Wall–Associated 19‐kDa Lipoprotein during the Course of Mycobacterial Infection

Mycobacterium tuberculosis induces apoptosis in human monocyte-derived macrophages (MDMs) during the early stages of infection. We investigated the proapoptotic role of cell wall-associated mycobacterial 19-kDa lipoprotein and the possible association between 19-kDa lipoprotein signaling and production of proinflammatory cytokines. Purified mycobacterial 19-kDa lipoprotein, 19-kDa lipoprotein-expressing M. smegmatis (M. smegmatis 19+), 19-kDa lipoprotein knockout (KO) M. tuberculosis, and 19-kDa lipoprotein KO M. bovis bacille Calmette-Guerin (BCG) strains were analyzed for their ability to induce apoptosis in MDMs. The 19-kDa lipoprotein and infection with M. smegmatis 19+ induced apoptosis in MDMs. M. tuberculosis and BCG KO strains had significantly decreased abilities to induce apoptosis. The 19-kDa lipoprotein proapoptotic signal was mediated by Toll-like receptor 2 but not by tumor necrosis factor-alpha. Only the release of interleukin (IL)-1 beta was decreased after infection with 19-kDa lipoprotein KO strains. These findings indicate that the 19-kDa lipoprotein is the main signal required to trigger both apoptosis and the release of IL-1 beta during the early stages of mycobacterial infection.

Sphingosine 1-phosphate induces antimicrobial activity both in vitro and in vivo

Sphingosine 1-phosphate (S1P), a polar sphingolipid metabolite, is involved in a wide spectrum of biological processes, including Ca(++) mobilization, cell growth, differentiation, motility, and cytoskeleton organization. Here, we show a novel role of S1P in the induction of antimicrobial activity in human macrophages that leads to the intracellular killing of nonpathogenic Mycobacterium smegmatis and pathogenic M. tuberculosis. Such activity is mediated by host phospholipase D, which favors the acidification of mycobacteria-containing phagosomes. Moreover, when it was intravenously injected in mycobacteria-infected mice, S1P reduced mycobacterial growth and pulmonary tissue damage. These results identify S1P as a novel regulator of the host antimicrobial effector pathways.

Early correction of cell cycle perturbations predicts the immunological response to therapy in HIV-infected patients

OBJECTIVE

To determine whether changes in the indices of HIV-associated cell cycle dysregulation (i.e., increased expression of cyclin B1 and abnormal nucleolar structure) may predict the level of immunological reconstitution in HIV-infected patients treated with highly active antiretroviral therapy (HAART).

METHODS

Cross-sectional and longitudinal analysis of viral load, CD4 T cell counts, cyclin B1 expression, and AgNOR number and area of distribution in 30 HIV-infected patients who were studied before and up to 6 months after initiation of HAART.

RESULTS

In HIV-infected individuals, the level of cell cycle dysregulation correlated with the type of response to HAART. While low levels of dysregulation were present in patients with complete (both virological and immunological) response to HAART, high levels were present in HAART-treated patients with limited CD4 T cell increases despite persistent viral suppression (immunological non-responders). Importantly, the level of correction of cell cycle dysregulation after 60 days of therapy predicted the level of immune reconstitution after 6 months.

CONCLUSION

These observations suggest that correction of cell cycle dysregulation predicts a good immunological response to HAART and that sequential analysis of cell cycle dysregulation might help to identify patients that could benefit from alternative, immune-based interventions in addition to standard HAART.

Specific changes in the posttranslational regulation of nucleolin in lymphocytes from patients infected with human immunodeficiency virus

Lymphocytes isolated from human immunodeficiency virus (HIV)-infected patients have dysregulated cell-cycle control, consisting of increased activation of the cyclin B1/p34 cdc2 complex and abnormal nucleolar structure. To better characterize the molecular features of the HIV-associated cell-cycle perturbations, we performed a detailed analysis of the posttranslational regulation of nucleolin, a key structural protein in the nucleolus. We found that, in concanavalin A-stimulated lymphocytes from HIV-infected patients, the inappropriate activation of the cyclin B1/p34 cdc2 kinase complex is temporally associated with increased threonine phosphorylation, augmented fragmentation, and prominent extranuclear and cell-surface localization of nucleolin. Importantly, increased lymphocyte apoptosis is observed at the time of cell-surface localization of nucleolin. These results may delineate a direct molecular link between abnormal activation of cyclin B1/p34 cdc2 and the changes in the nucleolar structure, thus providing a better molecular definition of HIV-associated cell-cycle dysregulation.

Cell cycle dysregulation during HIV infection: perspectives of a target based therapy

Human immunodeficiency virus (HIV) infection is characterized by a severe depletion of both CD4+ and CD8+ T cells, representing the result of virus-mediated killing of infected lymphocytes and the programmed cell death (apoptosis) of the uninfected bystander cells. Since only a small fraction of T lymphocytes are depleted by viral killing, apoptosis represents one of the most important mechanism of T cell death during HIV infection. Several apoptotic pathways can be triggered by the different stimuli: persistent T lymphocyte activation; altered death receptor (Fas, TNF-R, TRAIL R1-R2) membrane expression; viral proteins as well as gp120, Tat, and Nef; host factors such as the unbalance of cytokine synthesis by lymphocyte. Nevertheless, new evidences have demonstrated that the persistent HIV induced T cell activation and proliferation cause a cell cycle dysregulation resulting in a 5-fold increase in apoptotic cells. This perturbation represents a link between HIV infection, T cell activation, accelerated cell turnover and increased apoptosis and may thus represent a new therapeutic target. In fact, Interleukin-2 administration reverts such a cell cycle dysregulation and reduces activation induced T cell apoptosis. Herein we analyze the main HIV-related mechanisms of host cell death, that are dysregulation of the cell cycle and apoptosis induction of T lymphocytes. Finally, the role of cytokines at the site of infection and their association with apoptosis will be discussed to get insights into the immunological perturbations accounting for an accelerated disease progression. Current therapeutic approaches and strategies, like HAART and recombinant cytokines, that may, successfully, improve the immune-system dysregulation, are also discussed.

Exogenous interleukin-2 administration corrects the cell cycle perturbation of lymphocytes from human immunodeficiency virus-infected individuals

Human immunodeficiency virus (HIV)-induced immunodeficiency is characterized by progressive loss of CD4(+) T cells associated with functional abnormalities of the surviving lymphocytes. Increased susceptibility to apoptosis and loss of proper cell cycle control can be observed in lymphocytes from HIV-infected individuals and may contribute to the lymphocyte dysfunction of AIDS patients. To better understand the relation between T-cell activation, apoptosis, and cell cycle perturbation, we studied the effect of exogenous interleukin-2 (IL-2) administration on the intracellular turnover of phase-dependent proteins. Circulating T cells from HIV-infected patients display a marked discrepancy between a metabolic profile typical of G(0) and a pattern of expression of phase-dependent proteins that indicates a more-advanced position within the cell cycle. This discrepancy is enhanced by in vitro activation with ConA and ultimately results in a marked increase of apoptotic events. Conversely, treatment of lymphocytes with IL-2 alone restores the phase-specific pattern of expression of cell cycle-dependent proteins and is associated with low levels of apoptosis. Interestingly, exogenous IL-2 administration normalizes the overall intracellular protein turnover, as measured by protein synthesis, half-life of newly synthesised proteins, and total protein ubiquitination, thus providing a possible explanation for the effect of IL-2 on the intracellular kinetics of cell cycle-dependent proteins. The beneficial effect of IL-2 administration is consistent with the possibility of defective IL-2 function in vivo, which is confirmed by the observation that lymphocytes from HIV-infected patients show abnormal endogenous IL-2 paracrine/autocrine function upon in vitro mitogen stimulation. Overall these results confirm that perturbation of cell cycle control contributes to HIV-related lymphocyte dysfunction and, by showing that IL-2 administration can revert this perturbation, suggest a new mechanism of action of IL-2 therapy in HIV-infected patients.

Abnormal intracellular kinetics of cell-cycle-dependent proteins in lymphocytes from patients infected with human immunodeficiency virus: a novel biologic link between immune activation, accelerated T-cell turnover, and high levels of apoptosis

Human immunodeficiency virus (HIV)-infection is characterized by loss of CD4+ T cells associated with high levels of immune activation, T-cell proliferation, and lymphocyte apoptosis. To investigate the role of intrinsic perturbations of cell-cycle control in the immunopathogenesis of acquired immunodeficiency syndrome (AIDS), we studied the expression of cell-cycle-dependent proteins in lymphocytes from HIV-infected patients. Cyclin B1 expression, Nucleolar Organizer Regions (NORs) number, and NORs area of distribution were all consistently increased in HIV-infected patients, but returned to normal after effective antiretroviral therapy, suggesting that viral replication is directly implicated in the genesis of the observed changes. Analysis of cyclin B1 intracellular turnover showed that the increased cyclin B1 expression is (1) caused by defective degradation in the presence of normal rates of synthesis, and (2) is temporally associated with decreased levels of ubiquitination. After in vitro activation of lymphocytes from healthy individuals, cyclin B1 and cdc25 expression and ubiquitination, p34 cdc2 activity, NORs morphology, and C23/nucleolin localization showed a 72- to 96-hour cyclic pattern that led to a biologic state similar to baseline. On the contrary, complex but consistent changes of the same indices followed activation of T lymphocytes from HIV-infected patients, resulting in a 5-fold increase in apoptosis. Overall, our data indicate that a profound dysregulation of cell-cycle control is present in lymphocytes from HIV-infected patients. This finding may provide a novel biologic link between immune activation, accelerated lymphocyte turnover, and increased apoptosis during HIV infection.

Exposure of nonmigratory pigeons to mancozeb: a sentinel model for humans

The use of pesticides in agriculture has increased over the last decade. Their widespread, often uncontrolled use causes thousands of people to be daily exposed to environmental agricultural chemicals, resulting in acute and chronic health effects. At present there is a paucity of data on the potential adverse effects of exposure to low levels of mancozeb for prolonged periods. In order to investigate the effects of mancozeb exposure on pulmonary wildlife populations, tracheas and lungs of nine 1- to 7-yr-old nonmigratory pigeons raised near peach orchards and vineyards repeatedly sprayed with the fungicide were examined. The experimental situation allowed us to evaluate the long-term natural toxicity of mancozeb as a sentinel for human populations occupationally exposed to fungicides. The use of nonmigratory pigeons may serve as an important biological source from which helpful data may be obtained for assessing risks to human health and gaining new insight into pathogenetic mechanisms.

Presence of papillomavirus-like DNA sequences in cutaneous fibropapillomas of the goat udder

Papillomatous lesions were isolated from the mammary skin of goats and examined for evidence of papillomavirus (PV) infection by various criteria, including gross morphology, histology and DNA hybridization. Although some lesions showed gross papillomatous morphological and histological features similar to those caused by papillomavirus in other species, no viral particles were detected. Reverse slot hybridization revealed cross-hybridization between DNA extracted from goat mammary papillomas and human papillomaviruses (HPV). Southern blot, using ovine papillomavirus (OPV) and bovine papillomavirus type 5 (BPV 5) DNA probes under conditions of reduced stringency (Tm -40 degrees C), detected homologous sequences in 40% of the biopsies. DNA fragments corresponding probably to a monomeric form (7000-8000 bp) of an unknown papillomavirus genome were detected. This study provides evidence for the existence of papillomavirus-like sequences in caprine mammary papillomas and suggests that a papillomavirus is likely to be involved in the development of precancerous lesions of goat mammary skin.

Voluntary facial expression of emotion: comparing congenitally blind with normally sighted encoders

The ability of congenitally blind persons to produce voluntarily facial expressions of a number of emotions was compared with that of normally sighted individuals using both objective facial measurement and observer recognition. Results revealed that there were almost no significant differences between blind and sighted participants with respect to the number and type of facial action units produced. The portrayals of the blind participants were significantly more poorly recognized by observers than were those of the sighted participants (except for happiness). Correspondence analyses of the data showed differences between sighted and blind participants in the dimensional structure of the expressions (as based on the similarity among emotions with respect to both objective measurement and judgments). Overall, the data relavitize earlier conclusions on the facial expression of blind as compared with sighted persons and suggest specific hypotheses and procedures for further work in this area.

Sulodexide versus calcium heparin in the medium-term treatment of deep vein thrombosis of the lower limbs

Thirty adult patients with distal, monolateral deep vein thrombosis of the lower limbs were randomly treated for sixty days either with subcutaneous Ca-Heparin or with Sulodexide, administered IM for ten days and orally for fifty days. The thrombus accretion above the knee, the venous pressures of the affected leg, the clinical symptomatology, and some laboratory coagulative tests were monitored throughout the administration period. Local tolerability of the two treatments was also evaluated. The two applied treatments evidenced a net antithrombotic activity, preventing thrombus accretion above the knee, improving with the same efficacy the venous pressures in the affected legs, and similarly reducing clinical symptoms, with a quick and statistically significant trend toward normalization. Blood fibrinogen was significantly lowered by both drugs, while only Ca-heparin yielded a prolongation of activated partial thromboplastin time. Local tolerability of treatments was better for the mainly oral Sulodexide administrations, while subcutaneous Ca-heparin often induced small, though transient, hematomas.

Clinical-anamnestic and instrumental data in outpatients suffering from venous disease

The authors studied 200 consecutive outpatients with symptoms due to venous disease of the lower limbs. All the patients underwent anamnestic, clinical and instrumental evaluation (c.w. Doppler velocimetry and strain-gauge plethysmography). The results of this study showed that some anamnestic and clinical data are significantly related to venous disease detected by instrumental techniques. The superficial and deep vein hypertension were, instead, correlated to oral contraceptive use.

Evaluation of regional haemodynamics and alterations of vascular wall of the lower limbs in hypertensive subjects

This study was designed to analyse the relationship between arterial hypertension and changes in arterial blood flow and vascular wall damage of the lower limbs in hypertensive patients with various degrees of hypertension. Six hundred and fifty-four hypertensive patients (421 males and 233 females) aged 35 to 70 years and 88 healthy subjects (63 males and 25 females) aged 39 to 60 years were studied. Strain-gauge plethysmography of the lower limbs was used to calculate arterial calf blood flow (RF), arterial calf blood flow after post-ischaemic hyperaemia (PF), basal and minimal vascular resistances (BVR and MVR), time to reach peak flow (tPF), time until 50% reduction of peak flow (tT1/2) and total recovery time (tT). In 108 (67 males and 41 females) of the hypertensive patients, a morphological study by echo-Doppler duplex scanning of the popliteal artery was performed to measure medial-intimal thickening and popliteal lumen diameter. Our results indicate that regional haemodynamics of the lower limbs worsened in hypertensives in comparison with control subjects. In addition, the change in peripheral haemodynamics was related to the degree of hypertension. Moreover, medial--intimal thickening was significantly (P < 0.05) higher in severe hypertensives than mild hypertensives. Popliteal lumen diameter was significantly (P < 0.05) lower in severe hypertensives than moderate and mild hypertensives. In all these subjects mean blood pressure was correlated directly (r = 0.31; P < 0.001) with medial-intimal thickening and inversely (r = -0.37; P < 0.001) with popliteal lumen diameter. Multiple regression analysis indicated that mean blood pressure, age and serum cholesterol were independently correlated to medial-intimal thickening. This relationship was not influenced by the diabetic patients and smokers among the groups. Our results indicate that hypertension impairs peripheral flow and encourages the development of medial-intimal thickening.

Silicate pneumoconiosis in pigs: optical and scanning electron microscopical investigations with X-ray microanalysis

Four cases of silicate pneumoconiosis are described in pigs raised near several chalk quarries and two cement works. The pulmonary changes were characterized by thickened alveolar septa, resulting in distorted airspaces, and small foci of initial fibrosis. In the bronchiolar and alveolar sites, as in the interstitium, free and intracytoplasmic dust was detected. An energy dispersive X-ray microanalysis coupled with a scanning electron microscope revealed that this dust was composed mainly of silicon, calcium, potassium, sulphur, aluminium and iron. In lung-associated lymph nodes, severe lymphoid cell depletion and dilatation of peritrabecular and subcapsular sinuses were constant findings. The inorganic material found in the lymph nodes contained the elements listed above. Air samples from the same geographical area revealed particulate pollutants, the qualitative features of which were similar to those found in lung and lymph nodal tissue. It is concluded that domestic animals raised in polluted environmental conditions represent an important biological source from which helpful data may be obtained for assessing risks to human health.