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Biomedical subjects

A Calligaro

Publications and source records attributed to A Calligaro.

At least 19 recordsLinked to original sources
PubMed1992

Phospholipid hydroperoxide glutathione peroxidase of rat testis. Gonadotropin dependence and immunocytochemical identification.

A high glutathione peroxidase activity toward phospholipid hydroperoxides is present in rat testis. The attribution of this activity to the selenoenzyme phospholipid hydroperoxide glutathione peroxidase (PHGPX) was supported by cross-reactivity with antibodies raised against pig heart PHGPX which had been purified and characterized. Rat testis PHGPX is partially cytosolic and partially linked to nuclei and mitochondria. The soluble and organelle-bound enzymes appear identical by Western blot analysis. PHGPX, but neither selenium-dependent nor non-selenium-dependent glutathione peroxidase activity, is expressed in testes only after puberty, disappears after hypophysectomy, and is partially restored by gonadotropin treatment. Specific immunostaining of testes by antiserum against PHGPX appears as a fine granular brown pattern localized throughout the cytoplasm in more immature cells but is confined to the peripheral part of the cytoplasm, the nuclear membrane, and mitochondria in maturating spermatogenic cells. As expected, immunostaining of spermatogenic cells in hypophysectomized animals was negative, but gonadotropin treatment only marginally increased the immunoreactivity. The expression of PHGPX in testes is consistent with the previously described specific requirement for selenium for synthesis of a 15-20-kDa selenoprotein which is related to the production of functional spermatozoa.

Animals↗
PubMed1992

Lymphatic vessels of the human dental pulp in different conditions.

The characteristics of the lymphatic vessel endothelial wall have been investigated in human normal and inflamed dental pulps. In normal pulps the endothelial wall is characterized by the presence of micropinocytotic vesicles and intraparietal channels. In the inflamed pulpal tissue, where an increase in interstitial fluid pressure occurs, the distended endothelial wall presents open junctions between endothelial cells and the openings of the intraparietal channels. Moreover the micropinocytotic vesicles disappear. The cytoplasm of the endothelial cells is characterized by the presence of numerous Weibel-Palade bodies, which increase in number in the dilated vessels. In the fibrillar apparatus surrounding the lymphatic vessel wall collagen fibrils are the prevalent component, while elastic fibers are not present. The different morphological properties of the lymphatic vessels are compared and discussed with regard to the variation of the functional conditions of the tissue.

Adult↗
PubMed1992

HLA haplotype segregation and ultrastructural study in familial immotile-cilia syndrome.

The immotile-cilia syndrome (ICS) is a congenital disorder characterized by dysmotility or even complete immotility of the cilia in the ciliated epithelia. The most frequent consequences include recurrent airway infections from early childhood. Neonatal asphyxia often occurs. Males are usually sterile, whereas females may be fertile or infertile. The disease is inherited as an autosomal recessive trait, but previous attempts to localize the ICS susceptibility gene have so far been unsuccessful. Here, we present the case of two sib pairs affected by ICS from two unrelated families. The electron microscopic investigation of nasal biopsies showed structural anomalies of the cilia, characterized by single microtubules or doublets, arranged randomly in the axoneme. Histocompatibility antigen (HLA)-genotyping of all family members revealed: 1) a significant association of ICS with the HLA-DR7; DQW2 haplotype, which is shared by all the affected sibs (P = 0.0099; RR = 25.94); 2) a possible linkage of the ICS susceptibility gene with HLA, both the affected sibs being HLA-identical, the healthy brother in family B being HLA-different (sib-pair analysis: P less than 0.001).

Child, Preschool↗
PubMed1992

Cyclosporin A in a pregnant patient affected with systemic lupus erythematosus.

Few data regarding the use of cyclosporin A (CyA) in pregnancy are available and those available refer mainly to transplant recipients and not to patients with connective tissue diseases. We report the case of a patient with systemic lupus erythematosus (SLE), taking CyA before, during and after her pregnancy at a dose of 4 mg/kg per day. CyA was effective in controlling SLE activity and no side effects were observed in mother or baby. The lack of teratogenicity in this case was in keeping with previous reports in experimental systems, animals and human transplant recipients. If our observation is confirmed by further studies, CyA might become useful in the treatment of pregnant patients with SLE.

Adult↗
PubMed1992

Proliferative and functional stages of rat ameloblast differentiation as revealed by combined immunocytochemistry against enamel matrix proteins and bromodeoxyuridine.

A double-staining immunocytochemical technique was used for the simultaneous detection, at the light- and electron-microscopical level, of proliferating bromodeoxyuridine (BrdU)-labelled cells and enamel protein (EP)-producing cells in the inner enamel epithelium (IEE) of rat tooth germ. BrdU-positive cells were found in the region of the IEE close to the cervical loop and never displayed EP-like immunoreactivity. BrdU-immunoreactivity was confined to the nucleus of replicating cells. In contrast, epithelial cells displaying EP-like immunoreactivity were found in the region of the forming dental cusp and were consistently BrdU-negative. EP-like immunoreactivity was detectable in the cytoplasmic compartments involved in the exocrine secretion pathway and in the extra-cellular matrix close to EP-immunoreactive cells. These data support the view that withdrawal from the cell cycle in the IEE is a temporal prerequisite for acquiring the functional competence of secreting EP. Moreover, cycling cells and secretory cells in the IEE constitute two separate compartments that are spatially defined, and that exhibit clear-cut staining patterns with respect to BrdU- and EP-immunoreactivity, respectively. We thus propose that BrdU-incorporation and EP-production may be used as specific markers of the differentiation of the IIE cells in studies of the possible role of growth factors, their receptors and oncoproteins in this tissue.

Ameloblasts↗
PubMed1992

Antiphospholipid antibodies in mixed connective tissue disease.

We studied the prevalence and clinical significance of antiphospholipid antibodies (ab) in 28 patients affected with well-defined mixed connective tissue disease (MCTD). Forty-two patients affected with systemic lupus erythematosus (SLE) and 60 healthy subjects were also evaluated, as controls. In MCTD the prevalence of anticardiolipin (aCL) ab was: IgG high level 17.8% (p less than 0.01 versus healthy controls), IgG low level 7.1% and IgM high level 7.1%. No patients had low level of aCL IgM, lupus anticoagulant or false positive VDRL. The aCL profile was similar to that found in SLE patients, but in SLE all prevalences were higher than in MCTD. Furthermore, in MCTD patients the aCL ab were correlated with thrombocytopenia but not with recurrent thrombosis and/or abortions.

Adult↗
PubMed1992

Detection and quantitation in rat tissues of the superparamagnetic magnetic resonance contrast agent dextran magnetite as demonstrated by electron spin resonance spectroscopy.

RATIONALE AND OBJECTIVES: The compound studies in this article is a superparamagnetic macromolecular complex of magnetite cores coated with hydrophilic dextran, which is under active investigation as a contrast agent for magnetic resonance imaging (MRI) in liver and spleen. The biodistribution of paramagnetic compounds is problematic and is usually studied by histochemical reactions or by radiolabeling the compound under study. The purpose of this article is to show how electron spin resonance (ESR) spectroscopy detects dextran magnetite (DM) particles in tissues. METHODS: DM injected intravenously in the experimental animal was detected in some reticulo-endothelial organs by ESR. The spectroscopic study was validated using electron microscopy and electron-probe microanalysis. RESULTS: DM exhibits an ESR spectrum; ESR delineated the distribution of DM distribution in liver, spleen, bone marrow, and blood as a function of time. The blood clearance was biphasic, dependent on the size of particles. CONCLUSIONS: ESR spectroscopy is a highly sensitive and reproducible method of studying DM distribution.

Animals↗
PubMed1992

Immunohistochemical evidence for the occurrence of endothelin in the vascular endothelium of normal and inflamed human dental pulp.

The occurrence and distribution of the regulatory peptide endothelin in normal and inflamed human dental pulp was studied by immunocytochemistry. Endothelial cells in both normal and inflamed pulp displayed endothelin-like immunoreactivity. Neither pulp cells nor dental nerves were immunoreactive. No significant change in the distribution of endothelin immunoreactivity could be detected in the samples of inflamed pulp tissue, the immunoreactive material being detectable only within the endothelium. However, the intensity of the immunostaining was less intense in the samples of inflamed pulp. It is reasonable to presume that endothelin, produced and released locally by endothelial cells, may participate via a paracrine mechanism in the regulation of blood pressure and flow in normal and pathological human dental tissues.

Adolescent↗
PubMed1992

Dermal lymphatics in myotonic dystrophy.

Myotonic dystrophy is an hereditary disorder of several organ systems. Skeletal muscle is a principal target organ, but abnormalities also occur in the peripheral microcirculation. Because morphological and functional changes in the dermal blood microcirculation may affect interstitial fluid drainage of the skin, we examined dermal lymphatic morphology in adult patients with myotonic dystrophy. Skin biopsies were taken from the big toe from patients with myotonic dystrophy (age 18-50 years) and subjected to light and electron microscopy; five healthy subjects served as controls. The salient findings in myotonic dystrophy were ultrastructural changes of the lymphatic endothelial cells and the fibrillar elements that surround the lymphatic wall. These abnormal lymphatic findings are interpreted in light of changes in the blood microvasculature and loose connective tissue in this disorder.

Adolescent↗
PubMed1991

Immunohistochemical localization of endothelin-like immunoreactivity in human tooth germ and mature dental pulp.

The distribution in oral tissues of endothelin, a multifunctional peptide originally identified within endothelial cells, and subsequently in some epithelial cells, neurons and neuroendocrine cells, has not been investigated yet. We have studied the localization of endothelin-like immunoreactivity in human tooth germ and mature dental pulp by immunohistochemical techniques. Such immunoreactivity was detected only within endothelial cells in both mature dental pulp and developing tooth. Arteries and veins of various sizes as well as small thin vessels displayed endothelin-like immunoreactivity. In the tooth germ, the cells of the enamel organ or the precursors of the odontoblasts were found unreactive. In the mature pulp, no cells of the stroma or nerves displayed endothelin-like immunoreactivity. These findings suggest that vascular endothelium may be the only source of endothelin in human dental tissues. It is tentatively proposed that endothelin released in mature tooth pulp may participate in the regulation of the pulpal blood flow. Although the possible role of endothelin in developing tissues is far from being clear, the mitogenic effects and the proto-oncogenes expression induced by endothelin in some cells raise the possibility that this peptide might also play a role during tooth development.

Adult↗
PubMed1991

Lymphatic vessels in the healthy human dental pulp.

The lymphatic vessels of the dental pulp have been studied in non-carious teeth of young people. A network of lymphatic vessels drains the pulpal tissue. The lymphatic capillaries are characterized by a thin wall with an irregular profile. Cellular projections rise from the endothelial cells. Micropinocytotic vesicles and intercellular adjoining structures are the main mechanisms for the lymph formation. Multivesicular structures, Weibel-Palade bodies and paracrystalline inclusions have been observed.

Child↗
PubMed1991

Lymphatic vessels in the developing diaphragm of the rat.

Diaphragms of fetal, neonatal and young albino rats have been observed both under light and electron microscopes to examine the presence and distribution of lymphatic vessels and their morphological features. In fetal diaphragms of between 18 and 22 days of gestation, no normal lymphatic vessels can be seen; only after birth, specifically in neonatal and 2-day-old rats, small lymphatic vessels appear; they are in close proximity to the blood vessels in the inner areas of the muscle. As the rats get older, lymphatic vessels are also observed in the subserosa where an abundant connective tissue is present. The fine structure of diaphragmatic lymphatic vessels is different at different ages. In neonatal rats of up to 2 days, the endothelial wall is very thin and often holed. The relationships between contiguous endothelial cells are characterized by simple end-to-end or overlapping structures. The basement membrane is virtually absent. Within the first week of life, the endothelial wall becomes more complex; along the wall, complex interdigitations between two contiguous endothelial cells often touch. A discontinuous basement membrane and collagen and elastic fibers surround the vessels. In the older rats (from 14 to 25 to 140 days), next to the complex interdigitations which characterize the junction between two contiguous endothelial cells, cellular flaps interdigitate forming a channel which opens out either to the exterior or the interior of the vessel. Dense bundles of elastic and collagen fibers are closely apposed to the endothelial wall.

Animals↗
PubMed1991

Immunocytochemical evidence for the presence of somatostatin-like immunoreactive nerves in human dental pulp.

Specific antiserum to somatostatin was used for the immunocytochemical detection of this neuropeptide in human dental pulp. Immunoreactive axon varicosities were observed in the radicular as well as coronal pulp. Fibers displaying somatostatin-like immunoreactivity were detectable within radicular nerve trunks and were found to be associated mainly with blood vessels. Nevertheless, positive fibers with no apparent relation to blood vessels were also observed. No pulp cell was found to be immunoreactive. Previous physiological studies demonstrated that somatostatin may function as a regulatory peptide in feline dental pulp via a pre-synaptic inhibition of substance P release from sensory nerve terminals. It is tempting to speculate that such a mechanism may also be effective in human teeth and may be of value in the regulation of pulpal blood flow and in situations when sensory nerve fibers are activated, e.g., during pulpal inflammation.

Axons↗
PubMed1991

The effect of ethanol and other alcohols on morphometric parameters of rat small intestinal microvillous vesicles.

We have assessed the morphometric parameters of rat small intestinal microvillous vesicles, prepared by a Ca(2+)-precipitation method, from normal, long term ethanol-treated and pair-fed saccharose -treated control rats. The vesicles from normal rats were also directly exposed to ethyl, butyl and benzyl alcohols, respectively. Computerized morphometric analysis was carried out on electron micrographs of microvillous vesicles. The size of vesicles from ethanol-treated rats, as well as control rats, was significantly reduced as compared to normals. Direct exposure of vesicles to alcohols significantly increased vesicle dimensions, with a potency order reflecting the liposolubility of alcohols. These data support the hypothesis that variations in vesicle diameter may be ascribed at least in part to the fluidizing effect of alcohols. Thiamin transport by the vesicles has been measured in the presence of ethanol. The time course of thiamin uptake was not affected by ethanol.

Alcoholism↗
PubMed1991

Prevalence and characteristics of anti-single-stranded DNA antibodies in localized scleroderma. Comparison with systemic lupus erythematosus.

Prevalence, levels, and immunoglobulin classes of anti-single-stranded DNA antibodies were determined by an enzyme-linked immunosorbent assay in 52 patients with localized scleroderma (33 with morphea, four with generalized morphea, and 15 with linear scleroderma), in 60 healthy controls, and, for comparison, in 31 patients with systemic lupus erythematosus. Localized scleroderma revealed a significant prevalence of anti-single-stranded DNA antibodies, mainly characterized by high levels and IgM and IgA isotypes. Comparison of antibody characteristics in different clinical forms of localized scleroderma showed some significant differences (levels and immunoglobulin isotypes). Comparison with systemic lupus erythematosus showed that frequency, high levels, and IgG isotype of anti-single-stranded DNA antibodies significantly prevailed in systemic lupus erythematosus, while the IgM isotype significantly prevailed in localized scleroderma. However, generalized morphea and linear scleroderma did not significantly differ from systemic lupus erythematosus as regards antibody frequency and prevalence of high antibody levels.

Adult↗
PubMed1991

Scanning and transmission electron microscopy of rabbit heart lymphatic capillaries.

The ultrastructural characteristics of the lymphatic capillaries of the rabbit heart were examined by scanning and transmission electron microscopy (SEM and TEM) using similar technical preparation. SEM defined the interrelationships between endothelial cells including the pocket-like structures formed by overlapping between cells and the corresponding intercellular bridges. Except for rare spindle cells apposed on the luminal surface of the endothelium seen only on SEM, these features were confirmed by TEM. On the abluminal side of the lymphatic capillary wall, a rich network of filaments and fibrils was detectable using both ultrastructural techniques. These two modalities (SEM and TEM) complement one another in defining the microanatomy of the lymphatic capillary.

Animals↗