The product of X-linked Kallmann's syndrome gene (KAL1) affects the migratory activity of gonadotropin-releasing hormone (GnRH)-producing neurons

X-linked Kallmann's syndrome (KS) is a genetic disease characterized by anosmia and hypogonadism due to impairment in the development of olfactory axons and in the migration of gonadotropin-releasing hormone (GnRH)-producing neurons. Deletions or point mutations of a gene located at Xp22.3 (KAL1) are responsible for the disease. This gene encodes for a secreted heparin-binding protein (KAL or anosmin-1) which exhibits similarities with cell-adhesion molecules. In the present study, we show for the first time a direct action of anosmin-1 on the migratory activity of GnRH neurons. Specifically, we exposed immortalized migrating GnRH neurons (GN11 cells) to conditioned media (CM) of COS or CHO cells transiently transfected with human KAL1 gene in microchemotaxis and collagen gel assays. We found that anosmin-1-enriched media produced a cell-specific chemotactic response of GN11 cells. None of the CM enriched on three forms of anosmin-1 carrying different missense mutations (N267K, E514K and F517L) found in patients affected by X-linked KS affected the chemomigration of GN11 cells. Anosmin binds to the GN11 cell surface by interacting with the heparan sulphate proteoglycans, and the chemotactic effect of anosmin-1-enriched CM can be specifically blocked by heparin or by heparitinase pretreatment. These results strongly suggest an involvement of anosmin-1 in the control of the migratory behaviour of GnRH neurons and provide novel information on the pathogenesis of KS.

Degranulation of paneth cells via toll-like receptor 9

The release of antimicrobial peptides and growth factors by Paneth cells is thought to play an important role in protecting the small intestine, but the mechanisms involved have remained obscure. Immunohistochemistry and immunofluorescence showed that Paneth cells express Toll-like receptor 9 (TLR9) in the granules. Injection of mice with oligonucleotides containing CpG sequence (CpG-ODNs) led to a down-modulation of TLR9 and a striking decrease in the number of large secretory granules, consistent with degranulation. Moreover CpG-ODN treatment increased resistance to oral challenge with virulent Salmonella typhimurium. Moreover, our findings demonstrate a sentinel role for Paneth cells through TLR9.

Desmocollin 1 expression and desmosomal remodeling during terminal differentiation of human anagen hair follicle: an electron microscopic study

The terminal differentiation (TD) program of keratinocytes of the human hair follicle (HF) occurs with specific temporal and spatial features in the various layers of the inner root sheath (IRS) and in the innermost layer of the outer root sheath (companion layer). This process is characterized by complex nuclear and cytoplasmic morphological changes, accompanied by profound modifications in intercellular junctions. As no correlation exists between the structure and the molecular composition of desmosomes during TD of the IRS/companion unit, the aim of our study was to investigate by transmission electron microscopy the remodeling of desmosomes in keratinizing cells of these compartments. By immunogold post embedding technique, we studied in anagen HFs the modulation of the synthesis of desmocollin 1 (Dsc1), a transmembrane glycoprotein specifically synthesized in the IRS and in the companion layer. Dsc1 immunoreactivity was actually confined to these compartments and tended to increase just before the level of TD, particularly in the Henle's layer and in the IRS cuticle. In Huxley's layer, the immunolabeling was patchy and in the companion layer Dsc1 synthesis was detected above the level of keratinization of Huxley's layer. In the whole IRS, concomitantly with TD, there was an abrupt and almost complete disappearance of Dsc1 synthesis. An asymmetric distribution of Dsc1 was noticed (i) between cells at different stages of differentiation and (ii) between cells belonging to layers with different spatial/temporal features of TD. Our results show that the ultrastructural modifications of desmosomes during TD of HF are paralleled by the modulation of the synthesis of desmocollin 1.

Prevention of spontaneous mammary adenocarcinoma in HER-2/neu transgenic mice by foreign DNA

Unmethylated CpG-oligodeoxynucleotides (CpG-ODNs) are recognized as a 'danger signal' and are potent immunostimulators. To test whether tumors might be prevented by maintaining the innate immune system on continuous alert, proto-neu transgenic female mice, which develop spontaneous mammary tumors, were systemically treated with CpG-ODNs at 10-day intervals. Tumor incidence and number of tumors/mouse were significantly lower in treated mice compared with the control group. Moreover, CpG-ODN systemic treatment significantly reduced lung metastases induced by intravenous inoculation of N202.1A cells derived from a spontaneous mammary carcinoma. Growth of established tumors was modestly inhibited after CpG-ODN systemic treatment but strongly on peritumoral application. Our data indicate that systemic repeated injection of CpG-ODN to maintain the innate immune system on continuous alert prevents the onset of genetically determined tumors and confers tumor protection when the tumor load is low.

Topical administration of a doxorubicin-specific monoclonal antibody prevents drug-induced mouth apoptosis in mice

One of the most severe side effects of anti-tumour chemotherapy is mucositis due to drug toxicity for rapidly dividing cells. We show here that anti-DXR monoclonal antibodies can prevent DXR-induced damage. Indeed, apoptosis, confined to the proliferative compartment of the basal mucosa, observed in the tongue of DXR-treated mice was completely inhibited by topical application of the anti-DXR antibodies.

Comparison of endothelium-dependent vasoactivity of internal mammary arteries from hypertensive, hypercholesterolemic, and diabetic patients

BACKGROUND

Endothelium-dependent relaxation is abnormal in a variety of diseased states. Despite the widespread use of the internal mammary artery (IMA) in coronary artery bypass grafting, there is a lack of comparative studies on IMA endothelial-dependent function in patients with major cardiovascular risk factors.

METHODS

An IMA segment from 48 selected patients undergoing coronary artery bypass grafting was harvested intraoperatively and assigned to one of four groups (n = 12): diabetics requiring therapy, hypertensives, hypercholesterolemic, and nondiabetic-normotensive-normocholesterolemic patients. Internal mammary artery specimens were cut into rings and suspended in organ bath chambers, and the isometric tension of vascular tissues was recorded. The IMA rings were (1) precontracted with norepinephrine, and the endothelium-derived relaxation was evaluated by cumulative addition of acetylcholine, (2) contracted with cumulative concentrations of endothelin-1, and (3) contracted with the nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine. Furthermore, the release of prostacyclin by the IMA rings was directly measured during basal tone conditions and at the end of the various pharmacologic interventions. Histology of IMA rings was randomly performed.

RESULTS

The results obtained in these experiments showed that IMA rings harvested from hypertensive patients have the greatest impairment of endothelium-dependent response to relaxant and contracting stimuli (p < 0.01 versus nondiabetic-normotensive-normocholesterolemic tissues; p < 0.05 versus hypercholesterolemic and diabetic tissues) and prostacyclin release in normal and stimulated conditions. To a lesser extent, hypercholesterolemic and diabetic tissues show similar depression (diabetic > hypercholesterolemic) both of relaxation and prostacyclin production, with respect to nondiabetic-normotensive-normocholesterolemic specimens (p < 0.05). Histology findings (scanning electron microscopy) did not differ in multiple sections from vessel studies.

CONCLUSIONS

Major cardiovascular risk factors affect the endothelium-dependent vasoactive homeostasis of human IMA differently. Depression of relaxation is highest in patients with a history of hypertension. These findings may be pertinent to early and long-term treatment of patients undergoing coronary artery bypass grafting.

A comparision between rapid Golgi and Golgi-Cox impregnation methods for 3-D reconstruction of neurons at the confocal scanning laser microscope

We utilized two widely used impregnation methods, the silver "rapid Golgi" and the mercuric Golgi-Cox methods, for three-dimensional (3-D) reconstruction of neurons at the confocal scanning laser microscope (CSLM), to determine which of them was more suitable for this application. The Golgi-Cox method is the most consistent arid the cleanest procedure with respect to the "rapid Golgi" one which always produces samples with scattered reflective granules that interfere with the image formation at the CSLM. The interneuronal tissue in the case of Golgi-Cox impregnated specimens (i.e. the non-impregnated tissue among impregnated neurons) contributes less to the decrease of reflected light during z-sectioning than in the case of "rapid Golgi" impregnation, but the mercury impregnated samples reflect less than the silver impregnated ones. Owing to the necessity during deep z-scanning to adjust the sensitivity of the CLSM detector the acquisition of images from the deeper planes of the sample may be difficult. In our opinion the "sandwich" mounting of the specimen between two coverslips is indispensable in order to make it possible to scan it from both sides and, thus reduce the penetration in the sample and the consequent distortion of the image. Neither of the impregnation methods used is completely suitable for CLSM observations due both to their intrinsic limitations and to those imposed by the sample thickness.

Pattern of expression of c-Myc, Max and Bin1 in human anagen hair follicles

BACKGROUND

We recently reported the presence of c-Myc immunoreactivity in two distinct regions of the inner root sheath (IRS) of human anagen hair follicles; they corresponded to the regions where keratinocytes of Henle's and Huxley's layers enter the terminal differentiation phase that will lead to their exfoliation in the pilary canal. These regions were denoted lower (LR) ring and upper ring (UR).

OBJECTIVES

To extend these observations to other genes connected to c-Myc and specifically to Max and Bin1. Max is the best known heterodimeric partner of c-Myc, interacting with its C-terminal domain, and Bin1 is an adaptor protein interacting with its N-terminal domain.

METHODS

Human anagen hair follicles were processed for c-Myc, Max and Bin1 immunohistochemistry and immunofluorescence. The presence of different isoforms of Bin1 was evaluated by Western blot analysis.

RESULTS

Analysis of sections cut in several planes, including tangential, demonstrated the presence of a third ring of c-Myc-positive cells (intermediate ring; IR) in the cuticle of the IRS corresponding to the region where this thin layer undergoes keratinization. Max immunoreactivity was observed in the three layers of the IRS starting in the lower bulbar region and ending in each of them at the level of the corresponding c-Myc-positive ring. Bin1 immunoreactivity was clearly distinguished only in Huxley's layer and in the cuticle, starting in some cells below the UR and terminating at the level of the latter. The companion layer of the outer root sheath was also labelled up to the infundibular region. Max and Bin1 immunostaining were less consistently observed in other skin adnexae and in the epidermis.

CONCLUSIONS

The results indicate that the asynchronous differentiation along the axis of the hair follicle of the different layers of the IRS and of the companion layer involves the expression of different genes that are interrelated in the so-called 'Myc network'. The specific localization of c-Myc in the IRS only at the level of the discrete and limited regions of the three rings appears to be the hallmark of the switch from differentiation to terminal differentiation/cell deletion.

c-Myc expression in human anagen hair follicles

The hair follicle represents a very attractive organ system for studying the precise balance between cell proliferation, growth, differentiation, and death of cells, because it periodically and regularly regenerates, retaining its morphogenetic signals throughout its life. One of the most intriguing oncogenes which is able to induce both cell growth and apoptosis, depending upon the environmental conditions, is c-myc. The aim of the present study was to investigate its presence and localization in human hair follicles by immunohistochemistry and immunofluorescence. Our observations demonstrated the consistent presence of two clusters of c-Myc-expressing cells in anagen follicles, located in two annular regions of the inner root sheath, at the border between cells characterized by putative trichohyalin granules and cells which are keratinized. The lower group belongs to Henle's layer, while the upper group belongs to Huxley's layer. c-Myc oncoprotein seems to favour apoptosis/differentiation and may be a marker for terminal differentiation of trichocytes, at least in the inner root sheath. Our findings agree with the interpretation that the complex morphology of the hair follicle reflects its complex function; the extrusion of a highly organized multicellular structure, the hair shaft, driven by another highly organized multicellular structure, the inner root sheath.

Tamoxifen chemoprevention of a hormone-independent tumor in the proto-neu transgenic mice model

We evaluated the effect of tamoxifen (TAM) on tumor development in proto-neu transgenic mice that spontaneously develop mammary carcinomas overexpressing the neu protein. These mammary carcinomas are hormone independent because superimposable growth of transplants was observed in females and males. Virgin transgenic mice treated with TAM from 24 weeks of age, ie., when subclinical mammary tumors are already present, showed a slightly accelerated tumor development. In contrast, transgenic mice treated with TAM starting at 12 weeks of age, when subclinical tumors are not yet present, showed a 50% reduction of tumor incidence. Light microscopy analysis of the mammary gland of these mice revealed an apparently normal ductal branching but a complete regression of the acini. In conclusion, TAM can prevent the occurrence of hormone-independent breast carcinoma if given early enough to inhibit normal cells.

Fluctuation of HER2 expression in breast carcinomas during the menstrual cycle

The hormonal milieu at time of tumor surgery seems to have a significant impact on survival in premenopausal breast cancer patients. Indeed, surgery performed during the follicular phase of the menstrual cycle was suggested to correlate with a poor prognosis. To investigate the relationship between prognosis and menstrual cycle at time of surgery, we analyzed the expression of some markers associated with tumor aggressiveness, such as the hormone receptors, HER2, p53, Bcl2, and cathepsin D in breast carcinomas obtained from 198 premenopausal women who underwent surgery during different phases of the menstrual cycle. HER2 overexpression was found to fluctuate in hormone receptor-positive tumors. In actual fact, 20% of the tumors removed during the follicular phase scored HER2-positive, versus 8% of those removed during the luteal phase. Similarly, a number of hormone receptor-positive tumor specimens, obtained from the same patients during follicular and luteal phases, were scored HER2-positive when the sample was removed during the follicular phase and HER2-negative when removed in the luteal phase. Southern blot analysis of the HER2 gene indicated that, in hormone receptor-positive cases, the overexpression of HER2 is often not associated with gene amplification. The finding that overexpression of the HER2 gene, associated with tumor aggressiveness, can fluctuate according to the hormonal milieu may explain the increased survival of patients operated during the luteal phase. It is also relevant to the selection and treatment of patients most likely to benefit from anti-HER2 antibody therapy.

Identification of type 1 5alpha-reductase in myelin membranes of male and female rat brain

The formation of the 5alpha-reduced metabolites of testosterone (T) and of progesterone (P) is a very active process in the brain, since the enzyme 5alpha-reductase (5alpha-R) is present in almost any central nervous system (CNS) structure. A particularly elevated 5alpha-R activity has been shown in myelin sheaths. Two isoforms of the enzyme have been cloned, with different localisation as well as different biochemical properties. The present study was performed to determine whether both isoforms of the 5alpha-R, or only one of them, are/is responsible for the enzymatic activity observed in myelin. Kinetic analyses have been performed on purified myelin membranes prepared from the male or female rat brain, using both T and P as substrates. The 5alpha-R present appears to possess a pH optimum at basic values. The Vmax values obtained in the Lineweaver-Burk analysis were comparable in male and female preparations independently on whether T or P were used as the substrates, suggesting that a single enzymatic form is present in all samples examined; the Km obtained using [14C]T (Km: male 1.14 microM; female 1.46 microM) or [14C]P (Km: male 0.5 microM; female 0.64 microM) as substrates, were in good agreement with those obtained for the recombinant type 1 isoform. These data suggest that the type 1 isoform is the most relevant 5alpha-R present in myelin. To confirm this, a new polyclonal antibody was raised against the type 1 5alpha-R enzymatic protein, and used in immunohistochemical studies. The experiments were performed on the optic nerve, a myelinated structure very rich in 5alpha-R activity and the results clearly indicated the presence of a specific type 1 enzyme immunoreactivity in the myelin sheaths of axons.

Three-dimensional reconstruction of the Meissner corpuscle of man, after silver impregnation and immunofluorescence with PGP 9.5 antibodies using confocal scanning laser microscopy

The 3-dimensional organisation of the neural component of the human Meissner corpuscle was studied after silver impregnation and following immunofluorescence for protein gene product 9.5 (PGP 9.5) by confocal scanning laser microscopy. The morphology of the Meissner corpuscle was found to show consistent differences depending on the labelling method used. After silver impregnation by the Winkelmann technique the branches of the afferent nerve fibres of the corpuscle showed both thin regions and varicose elements, the latter probably corresponding to the portions rich in mitochondria observed by transmission electron microscopy. The bulkier elements were never more than 5-6 microns in diameter. After immunolabelling for PGP 9.5 the nerve fibre branches in the corpuscle always presented flattened and discoidal expansions with a diameter of up to 30 microns. On the basis of what is known as to the mechanism of action of silver impregnations it is considered that the black precipitate preferentially labels the parts of neurons that are rich in neurofilaments. In any case the precipitate is deposited throughout the neuronal cytoplasm except in the mitochondria and the nucleus. Accordingly, in the varicosities of the Meissner corpuscles that are rich in mitochondria, there is little space for the formation of the precipitate. The use of antiserum against PGP 9.5, which labels the larger proteinaceous component of the axoplasm, demonstrates the complete architecture of the neural component of the Meissner corpuscle, and visualises the discoidal and flattened expansions which are absent in the impregnated corpuscles. It is concluded that immunostaining provides images of the corpuscles, and of peripheral neural structures that are in general closer to reality.

A simple method for overcoming some problems when observing thick reflective biological samples with a confocal scanning laser microscope

A simple device is described, which allows the range of depth of scanning to be reduced when observing thick reflecting biological samples with a confocal scanning laser microscope (CSLM). Thick histological sections of human skin and rat brain stem were mounted between two coverslips ('sandwich' style) and the optical tomography was performed from both sides by turning the 'sandwich' upside-down. The samples were impregnated using standard Golgi-Cox, 'rapid Golgi' or other silver methods. The ability to turn the 'sandwich' upside-down is particularly useful when the reflective structure inspected is deep inside the section, i.e., near the lower surface of the specimen, or when it is opaque to the laser beam or excessively reflective.

Central and peripheral nervous structures as seen at the confocal scanning laser microscope

Central neurons and peripheral nervous structures, e.g. cutaneous free endings, perifollicular nets, Meissners corpuscles and intramuscular fibres, were studied using various impregnation methods. The confocal scanning laser microscopes (CSLMs) used were equipped with different laser sources, in order to evaluate their limitations and advantages with these techniques and to contribute to a better understanding of the general morphology of the nervous system. When staining with silver sections with clouds of tiny silver granules which are beyond the resolution power of the conventional light microscope but which show a high reflectivity with the CSLM are obtained. Golgi-Cox mercuric impregnation, however, provides specimens which are precipitate-free, thus ensuring the reliability of information obtained. It does, however, have the disadvantage of being applicable only to the central nervous system. In all cases it is an advantage for the instrument to be fitted with different lasers (e.g. Ar and He-Ne), so as to optimize the images of samples impregnated with different methods. Notwithstanding the possibility that artefacts may distort the geometry of the sample and reduce the resolution, the images presented in this paper show that with careful selection of optical sectioning distances, the use of a suitable stack of sections and, if necessary, the aid of false electronic colours and of partial or complete rotation, it is possible to achieve a more precise interpretation of the morphology and organization of complex structures, such as those of the nervous system.

Localization of nitric oxide synthase immunoreactivity in mast cells of human nasal mucosa

Nitric oxide (NO)-synthase immunoreactivity has been detected for the first time in mast cells of human normal nasal mucosa, with an antibody specific for neuronal NO-synthase. Intense immunoreactivity was revealed in secretion granules of mast cells but was found in mast cell granules free in the extracellular matrix only in some instances; no reactivity was found in the cytoplasm of this or other cell types. These findings suggest that human nasal mast cells contain a particulate isoform of NO-synthase, which shares epitopes with neuronal NO-synthase and is rapidly removed from granules upon exocytosis.