Comparative lectin histochemistry on taste buds in foliate, circumvallate and fungiform papillae of the rabbit tongue.

Taste buds (TB) in the foliate, circumvallate and fungiform papillae of the rabbit tongue were examined with lectin histochemistry by means of light (LM) and electron (EM) microscopy. Biotin- and gold-labeled lectins were used for the detection of carbohydrate residues in TB cells and subcutaneous salivary glands. At the LM level, the lectins of soybean (SBA) and peanut (PNA) react with material of the foliate and circumvallate taste pores only after pretreatment of the section with neuraminidase. This indicates that the terminal trisaccharide sequences are as follows: Sialic acid-Gal-GalNAc in O-glycosylated glycoproteins or Sialic acid-Gal-GlcNAc in N-glycosylated glycoproteins. In fungi-form taste buds the lectins of Dolichos biflorus (DBA) and Helix pomatia (HPA), also specific to GalNAc residues, are reactive without preincubation with neuraminidase. Wheat germ agglutinin (WGA), specific to GlcNAc, reacts with TBs of all papillae; and the lectin from Ulex europaeus (UEA I), specific to fucose, binds to individual TB cells. The presence of sialic acid may protect mucus or other glycoproteins in TB cells and inside the taste pore from premature enzymatic degradation. In a post-embedding EM procedure on LR-White-embedded tissue sections, only gold-labeled HPA was found to bind especially on membrane surfaces of the microvilli which protrude into the taste pore; however HPA did not bind to the electron-dense mucus inside the taste pore. The mucus situated in the trough and at the top of the adjacent epithelial cells also is strongly HPA-positive, but is of different origin and composition than that found in the taste pore. These results demonstrate distinct carbohydrate histochemical differences between fungiform and circumvallate/foliate taste buds. The different configuration of galactosyl residues and the occurrence of mannose in circumvallate and foliate TBs leads to the suggestion that the lectin reactivities of TBs are not only due to the presence of mucins, but also to N-linked glycoproteins, possibly with a hormone-like paraneuronal function. A possible relationship to v. Ebner glands in these papillae is discussed.     

The presence of acetylcholinesterase-positive nerve fibres in the deep pineal gland and the pineal stalk but not in the superficial part of adult albino rats

Application of the histochemical method for testing acetylcholinesterase (AChE, EC 3.1.1.7) showed the presence of AChE-positive nerve fibers in the deep pineal gland and the pineal stalk but not in the superficial part of adult albino rats. These findings may indirectly support the existence of the potentially cholinergic innervation of at least some of the rat pinealocytes present in these parts of the gland and augment the evidence of the heterogeneity of the rat pinealocytes. It is possible that cholinergic neurons in the medial habenular nuclei or in the parasympathetic sphenopalatine ganglion may be a source of these AChE-positive fibres. The examination was performed at the light microscope level.     

Comparative lectin histochemistry on taste buds in foliate,circumvallate and fungiform papillae of the rabbit tongue

Summary Taste buds (TB) in the foliate, circumvallate and fungiform papillae of the rabbit tongue were examined with lectin histochemistry by means of light (LM) and electron (EM) microscopy. Biotin- and gold-labeled lectins were used for the detection of carbohydrate residues in TB cells and subcutaneous salivary glands. At the LM level, the lectins of soybean (SBA) and peanut (PNA) react with material of the foliate and circumvallate taste pores only after pretreatment of the section with neuraminidase. This indicates that the terminal trisaccharide sequences are as follows: Sialic acid-Gal-GalNAc in O-glycosylated glycoproteins or Sialic acid-Gal-GlcNAc in N-glycosylated glycoproteins. In fungiform taste buds the lectins of Dolichos biflorus (DBA) and Helix pomatia (HPA), also specific to GalNAc residues, are reactive without preincubation with neuraminidase. Wheat germ agglutinin (WGA), specific to GlcNAc, reacts with TBs of all papillae; and the lectin from Ulex europaeus (UEA I), specific to fucose, binds to individual TB cells. The presence of sialic acid may protect mucus or other glycoproteins in TB cells and inside the taste pore from premature enzymatic degradation. In a post-embedding EM procedure on LR-White-embedded tissue sections, only gold-labeled HPA was found to bind especially on membrane surfaces of the microvilli which protrude into the taste pore; however HPA did not bind to the electron-dense mucus inside the taste pore. The mucus situated in the trough and at the top of the adjacent epithelial cells also is strongly HPA-positive, but is of different origin and composition than that found in the taste pore. These results demonstrate distinct carbohydrate histochemical differences between fungiform and circumvallate/foliate taste buds. The different configuration of galactosyl residues and the occurrence of mannose in circumvallate and foliate TBs leads to the suggestion that the lectin reactivities of TBs are not only due to the presence of mucins, but also to N-linked glycoproteins, possibly with a hormone-like, paraneuronal function. A possible relationship to v. Ebner glands in these papillae is discussed.     

How host heterogeneity governs tuberculosis reinfection?

Recurrent episodes of tuberculosis (TB) can be due to relapse of latent infection or exogenous reinfection, and discrimination is crucial for control planning. Molecular genotyping of Mycobacterium tuberculosis isolates offers concrete opportunities to measure the relative contribution of reinfection in recurrent disease. Here, a mathematical model of TB transmission is fitted to data from 14 molecular epidemiology studies, enabling the estimation of relevant epidemiological parameters. Meta-analysis reveals that rates of reinfection after successful treatment are higher than rates of new TB, raising an important question about the underlying mechanism. We formulate two alternative mechanisms within our model framework: (i) infection increases susceptibility to reinfection or (ii) infection affects individuals differentially, thereby recruiting high-risk individuals to the group at risk for reinfection. The second mechanism is better supported by the fittings to the data, suggesting that reinfection rates are inflated through a population phenomenon that occurs in the presence of heterogeneity in individual risk of infection. As a result, rates of reinfection are higher when measured at the population level even though they might be lower at the individual level. Finally, differential host recruitment is modulated by transmission intensity, being less pronounced when incidence is high.     

Tissue basophils in vascular plexuses of the lateral ventricles of the brain in humans and various mammals]

By means of histological and histochemical methods cell composition of vascular plexuses in the lateral ventricles of the rats, dogs and man has been investigated. Besides ependymocytes, endotheliocytes, pericytes, myocytes in the microcirculatory bed, described in literature, tissue basophils (TB) have been revealed and what is more--only in dog and man. The most variable forms and localizations of TB are observed in vascular plexuses of the lateral ventricles of the human brain. The following varieties of TB can be defined: small with ortochromic granularity and large ones with abundant metachromic granularity. Sometimes degranulating TB occur. According to their localization they are divided into stromal (+interstitial++), perivascular subepithelial and intraepithelial. The variable TB localization in the vascular plexuses of the brain can probably demonstrate their participation in performing functions of the hematoencephalic barrier.     

Ultrastructural ultracytochemical investigation of human gastric carcinomas

We describe the ultrastructure of various types of gastric carcinoma cells as well as their histochemical properties as visualized at the electron-microscope level. The histochemical properties of tumour cells were compared with those of homologous normal epithelial cells. The localization and activity of ATPase, IDPase, acidic phosphatase and alkaline phosphatase as well as of the oxidoreductases (cytochrome oxidase, succinate dehydrogenase and NADH-dehydrogenase) were studied. Our findings demonstrated that, in tumour cells, a complicated process of structural-functional restructuring takes place. It seems that a number of ultracytochemical properties may be preserved or may disappear altogether; also, such properties may become enhanced or weaker. This heterogeneity of the histochemical properties of tumour cells is discussed with regard to the role of the stem (polypotent) cell in the process of the histogenesis (cytogenesis) of human gastric carcinomas.     

Ultrastructural and ultracytochemical investigation of human gastric carcinomas

Summary We describe the ultrastructure of various types of gastric carcinoma cells as well as their histochemical properties as visualized at the electron-microscope level. The histochemical properties of tumour cells were compared with those of homologous normal epithelial cells. The localization and activity of ATPase, IDPase, acidic phosphatase and alkaline phosphatase as well as of the oxidoreductases (cytochrome oxidase, succinate dehydrogenase and NADH-dehydrogenase) were studied. Our findings demonstrated that, in tumour cells, a complicated process of structural-functional restructuring takes place. It seems that a number of ultracytochemical properties may be preserved or may disappear altogether, also, such properties may become enhanced or weaker. This heterogeneity of the histochemical properties of tumour cells is discussed with regard to the role of the stem (polypotent) cell in the process of the histogenesis (cytogenesis) of human gastric carcinomas.In honour of Prof. P. van Duijn     

从甲状腺肥大细胞探讨胎儿器官肥大细胞的差异

研究肥大细胞在人胎儿甲状腺发育中数量、分布及组化性质的改变,以探讨胎儿器官发育中肥大细胞的差异。取45例不同胎龄的人胎甲状腺石蜡切片做甲苯胺蓝染色和阿尔辛蓝－－藏红染色,并测定肥大细胞的临界电解质浓度值及进行硫酸小蘖硷荧光染色。结果显示：3月龄胎儿甲状腺内开始出现肥大细胞,数量极少,主要分布在被膜及小叶间结缔组织内,甲苯胺蓝染色肥大细胞颗粒呈淡紫蓝色,阿尔辛蓝－－藏红染色呈蓝色,临界电解质浓度值较低,硫酸小蘖硷染色未见显黄色荧乐的肥大细胞,从3月龄到足月随着胎龄增长,肥大细胞数量缓慢增多,8月龄时肥大细胞经甲苯胺蓝染色,其颗粒呈紫红色,阿尔辛蓝－－藏红染色出现少量含红色和红蓝混合染色颗粒的肥大细胞,临界电解质浓度值偏高,可见少量显黄色荧光的肥大细胞,结果表明：在人胎儿3月龄时甲状腺发育中开始出现肥大细胞,但随胎儿发育肥大细胞的组化性质改变不明显。     

Action Potential Duration Heterogeneity of Cardiac Tissue Can Be Evaluated from Cell Properties Using Gaussian Green's Function Approach

Action potential duration (APD) heterogeneity of cardiac tissue is one of the most important factors underlying initiation of deadly cardiac arrhythmias. In many cases such heterogeneity can be measured at tissue level only, while it originates from differences between the individual cardiac cells. The extent of heterogeneity at tissue and single cell level can differ substantially and in many cases it is important to know the relation between them. Here we study effects from cell coupling on APD heterogeneity in cardiac tissue in numerical simulations using the ionic TP06 model for human cardiac tissue. We show that the effect of cell coupling on APD heterogeneity can be described mathematically using a Gaussian Green''s function approach. This relates the problem of electrotonic interactions to a wide range of classical problems in physics, chemistry and biology, for which robust methods exist. We show that, both for determining effects of tissue heterogeneity from cell heterogeneity (forward problem) as well as for determining cell properties from tissue level measurements (inverse problem), this approach is promising. We illustrate the solution of the forward and inverse problem on several examples of 1D and 2D systems.     

Co-localization of nitric oxide synthase immunoreactivity and NADPH diaphorase staining in neurons of the guinea-pig intestine

Summary Neuronal nitric oxide synthase (NOS), an enzyme capable of synthesizing nitric oxide, appears to be identical to neuronal NADPH diaphorase. The correlation was examined between NOS immunoreactivity and NADPH diaphorase staining in neurons of the ileum and colon of the guinea-pig. There was a one-to-one correlation between NOS immunoreactivity and NADPH diaphorase staining in all neurons examined; even the relative staining intensities obtained were similar with each technique. To determine whether pharmacological methods could be employed to demonstrate that NADPH diaphorase staining was due to the presence of NOS, tissue was pre-treated with N^G-nitro-l-arginine, a NOS inhibitor, or l-arginine, a natural substrate of NOS. In these experiments on unfixed tissue, it was necessary to use dimethyl thiazolyl tetrazolium instead of nitroblue tetrazolium as the substrate for the NADPH diaphorase histochemical reaction. Neither treatment caused a significant decrease in the level of NADPH diaphorase staining, implying that arginine and NADPH interact at different sites on the enzyme.     

Exposure to Second-Hand Smoke and the Risk of Tuberculosis in Children and Adults: A Systematic Review and Meta-Analysis of 18 Observational Studies

Background

According to WHO Global Health Estimates, tuberculosis (TB) is among the top ten causes of global mortality and ranks second after cardiovascular disease in most high-burden regions. In this systematic review and meta-analysis, we investigated the role of second-hand smoke (SHS) exposure as a risk factor for TB among children and adults.

Methods and Findings

We performed a systematic literature search of PubMed, Embase, Scopus, Web of Science, and Google Scholar up to August 31, 2014. Our a priori inclusion criteria encompassed only original studies where latent TB infection (LTBI) and active TB disease were diagnosed microbiologically, clinically, histologically, or radiologically. Effect estimates were pooled using fixed- and random-effects models. We identified 18 eligible studies, with 30,757 children and 44,432 adult non-smokers, containing SHS exposure and TB outcome data for inclusion in the meta-analysis. Twelve studies assessed children and eight studies assessed adult non-smokers; two studies assessed both populations. Summary relative risk (RR) of LTBI associated with SHS exposure in children was similar to the overall effect size, with high heterogeneity (pooled RR 1.64, 95% CI 1.00–2.83). Children showed a more than 3-fold increased risk of SHS-associated active TB (pooled RR 3.41, 95% CI 1.81–6.45), which was higher than the risk in adults exposed to SHS (summary RR 1.32, 95% CI 1.04–1.68). Positive and significant exposure–response relationships were observed among children under 5 y (RR 5.88, 95% CI 2.09–16.54), children exposed to SHS through any parent (RR 4.20, 95% CI 1.92–9.20), and children living under the most crowded household conditions (RR 5.53, 95% CI 2.36–12.98). Associations for LTBI and active TB disease remained significant after adjustment for age, biomass fuel (BMF) use, and presence of a TB patient in the household, although the meta-analysis was limited to a subset of studies that adjusted for these variables. There was a loss of association with increased risk of LTBI (but not active TB) after adjustment for socioeconomic status (SES) and study quality. The major limitation of this analysis is the high heterogeneity in outcomes among studies of pediatric cases of LTBI and TB disease.

Conclusions

We found that SHS exposure is associated with an increase in the relative risk of LTBI and active TB after controlling for age, BMF use, and contact with a TB patient, and there was no significant association of SHS exposure with LTBI after adjustment for SES and study quality. Given the high heterogeneity among the primary studies, our analysis may not show sufficient evidence to confirm an association. In addition, considering that the TB burden is highest in countries with increasing SHS exposure, it is important to confirm these results with higher quality studies. Research in this area may have important implications for TB and tobacco control programs, especially for children in settings with high SHS exposure and TB burden.     

Assessing Local Risk of Rifampicin-Resistant Tuberculosis in KwaZulu-Natal,South Africa Using Lot Quality Assurance Sampling

BackgroundKwaZulu-Natal (KZN) has the highest burden of notified multidrug-resistant tuberculosis (MDR TB) and extensively drug-resistant (XDR) TB cases in South Africa. A better understanding of spatial heterogeneity in the risk of drug-resistance may help to prioritize local responses.MethodsBetween July 2012 and June 2013, we conducted a two-way Lot Quality Assurance Sampling (LQAS) study to classify the burden of rifampicin (RIF)-resistant TB among incident TB cases notified within the catchment areas of seven laboratories in two northern and one southern district of KZN. Decision rules for classification of areas as having either a high- or low-risk of RIF resistant TB (based on proportion of RIF resistance among all TB cases) were based on consultation with local policy makers.ResultsWe classified five areas as high-risk and two as low-risk. High-risk areas were identified in both Southern and Northern districts, with the greatest proportion of RIF resistance observed in the northernmost area, the Manguzi community situated on the Mozambique border.ConclusionOur study revealed heterogeneity in the risk of RIF resistant disease among incident TB cases in KZN. This study demonstrates the potential for LQAS to detect geographic heterogeneity in areas where access to drug susceptibility testing is limited.     

A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection

Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.     

Phylogenetic polymorphism on lectin binding to junctional and non-junctional basal lamina at the vertebrate neuromuscular junction

The histochemical binding of seven fluoreceinated lectins was comparatively studied in muscular tissue from twenty three different animal species including mammalians, amphibians, avians and fishes. Special interest was taken in the exploration of the differential lectin-binding properties at the neuromuscular synapse. Binding to synaptic sites was demonstrated using lectins that recognizes N-acetylgalactosamine and among of them, Dolichus biflorus agglutinin (DBA), was the most specific. Nevertheless, DBA fails to stain endplates in the muscle from most of the avians and the fishes (including the Torpedo electric organ) indicating that a polymorphic distribution of glycoconjugates exist at the vertebrate neuromuscular junction. Other lectins such as Concanavalin A (ConA) or Wheat germ agglutinin (WGA), share a similar staining properties in all animals that we examined making an intense label over the complete muscle surface. Although the species-related polymorphism on lectin binding does not reveal a clear relationship with the evolutionary tree, they give an evidence on the chemical heterogeneity of molecules specifically concentrated at the neuromuscular junction.     

Derivation of the mesoscopic elasticity tensor of cortical bone from quantitative impedance images at the micron scale

This paper addresses the relationships between the microscopic properties of bone and its elasticity at the millimetre scale, or mesoscale. A method is proposed to estimate the mesoscale properties of cortical bone based on a spatial distribution of acoustic properties at the microscopic scale obtained with scanning acoustic microscopy. The procedure to compute the mesoscopic stiffness tensor involves (i) the segmentation of the pores to obtain a realistic model of the porosity; (ii) the construction of a field of anisotropic elastic coefficients at the microscopic scale which reflects the heterogeneity of the bone matrix; (iii) finite element computations of mesoscopic homogenized properties. The computed mesoscopic properties compare well with available experimental data. It appears that the tissue anisotropy at the microscopic level has a major effect on the mesoscopic anisotropy and that assuming the pores filled with an incompressible fluid or, alternatively, empty, leads to significantly different mesoscopic properties.     

Immunofluorescent localization of pig complement component 3, regardless of the presence or absence of detectable immunoglobulins, in hyperacutely rejected heart xenografts

Summary Rabbit heart xenografts transplanted into the neck of newborn pigs were all hyperacutely rejected within two hours regardless of the presence or absence of detectable endogenous immunoglobulins (Ig). Cryostat tissue sections were prepared from the rejected rabbit hearts and incubated with sheep polyclonal antibodies against pig complement component 3 (C₃), pig IgG and pig IgM. Specific immunoreaction was visualized by fluorescein-conjugated antibodies to sheep IgG. C₃ was localized mainly on the surfaces of vascular endothelial as well as myocardial cells, and the localization was not dependent upon the presence of pig immunoglobulins within the same tissue. Both pig IgG and IgM were detected only in the heart xenografts transplanted into suckled pigs, whereas no trace of immunoglobulin was found in those transplanted into circulating antibody-free presuckled pigs. Treatment with cobra venom factor (which inhibits complement activity) prior to transplantation prolonged xenograft survival and completely abolished C₃ immunostaining. The results provide new evidence at the histochemical level that the alternative pathway of complement is involved in hyperacute xenograft rejection of the species combination (rabbit to pig) used in this study.     

Methods for the study of liver cell heterogeneity

A large number of histological, histochemical and biochemical techniques are available for studying liver cell heterogeneity. Structural differences are recognized by morphometric analyses of electron micrographs. The zonal heterogeneity of enzyme activities can be demonstrated by histochemistry and more precisely by ultramicrobiochemical assays in microdissected periportal and perivenous tissue. Immunohistochemistry is useful for quantifying and localizing proteins, especially isoenzymes, without depending on their biological activity. The zonal quantification of specific mRNA can be achieved by in situ hybridization. The different structural and enzymic equipment of periportal and perivenous tissue found by these techniques has led to the concept of metabolic zonation. This hypothesis can be confirmed by determination of metabolic rates in perfused liver after selective zonal damage, in separated periportal and perivenous hepatocytes as well as in periportal and perivenous tissue of perfused liver by non-invasive techniques.