Expression of cytoskeletal proteins in developing human minor salivary glands

The presence of an epithelium at different stages of proliferation and differentiation raises interesting questions concerning the histogenesis, cell turnover and differentiation of normal salivary glands. In order to expand knowledge of these aspects, we investigated the expression of cytokeratins (CKs) 7,8,10,13,14,16,18 and 19, vimentin (VIM), and smooth muscle actin (SMA) in developing human minor salivary glands using monoclonal antibodies. Labial, buccal, palatine, and lingual salivary glands and those from the floor of the mouth were obtained from human fetuses (forensic postmortem) ranging in age from gestational weeks 10 to 29. Serial sections, 3 microm thick, were immunostained using a strepto-avidin-biotin technique. Reactivity for all antibodies was negative in the salivary gland epithelium during the developmental stages of bud formation, cord growth, and branching of cord. During canalization and cytodifferentiation, the glandular epithelial cells showed a positive reaction to some CKs and SMA. Cytokeratins 7, 8, 18, and 19 showed strong labeling in luminal duct cells that exhibited some degree of morphological differentiation. Myoepithelial cellc were recognized by antibodies to SMA. Cytoskeletal protein expression changes according to the cell type, degree of differentiation, and stage of morphological development of the glandular structure. These changes occur independently of the localization of the gland.     

Nevoid hypertrichosis and hypomelanosis

A girl with multiple lesions of nevoid hypertrichosis and linear hypopigmentation following Blaschko's lines is presented. She had no extracutaneous anomalies. We hypothesize that this unusual coexistence of skin lesions may represent a further example of "twin spotting".     

5,7-DHT-induced hippocampal 5-HT depletion attenuates behavioural deficits produced by 192 IgG-saporin lesions of septal cholinergic neurons in the rat

Adult Long-Evans male rats sustained injections of 5,7-dihydroxytryptamine into the fimbria-fornix (2.5 microg/side) and the cingular bundle (1.5 microg/side) and/or to intraseptal injections of 192 IgG-saporin (0.4 microg/side) in order to deprive the hippocampus of its serotonergic and cholinergic innervations, respectively. Sham-operated rats were used as controls. The rats were tested for locomotor activity (postoperative days 18, 42 and 65), spontaneous T-maze alternation (days 20-29), beam-walking sensorimotor (days 34-38), water maze (days 53-64) and radial maze (days 80-133) performances. The cholinergic lesions, which decreased the hippocampal concentration of ACh by about 65%, induced nocturnal hyperlocomotion, reduced T-maze alternation, impaired reference-memory in the water maze and working-memory in the radial maze, but had no effect on beam-walking scores and working-memory in the water maze. The serotonergic lesions, which decreased the serotonergic innervation of the hippocampus by about 55%, failed to induce any behavioural deficit. In the group of rats given combined lesions, all deficits produced by the cholinergic lesions were observed, but the nocturnal hyperlocomotion and the working-memory deficits in the radial maze were attenuated significantly. These results suggest that attenuation of the serotonergic tone in the hippocampus may compensate for some dysfunctions subsequent to the loss of cholinergic hippocampal inputs. This observation is in close concordance with data showing that a reduction of the serotonergic tone, by pharmacological activation of somatodendritic 5-HT(1A) receptors on raphe neurons, attenuates the cognitive disturbances produced by the intrahippocampal infusion of the antimuscarinic drug, scopolamine. This work has been presented previously [Serotonin Club/Brain Research Bulletin conference, Serotonin: From Molecule to the Clinic (satellite to the Society for Neuroscience Meeting, New Orleans, USA, November 2-3, 2000)].     

Neurotrophins and the immune system

The neurotrophins are a family of polypeptide growth factors that are essential for the development and maintenance of the vertebrate nervous system. In recent years, data have emerged indicating that neurotrophins could have a broader role than their name might suggest. In particular, the putative role of NGF and its receptor TrkA in immune system homeostasis has become a much studied topic, whereas information on the other neurotrophins is scarce in this regard. This paper reviews what is known about the expression and possible functions of neurotrophins and their receptors in different immune tissues and cells, as well as recent data obtained from studies of transgenic mice in our laboratory. Results from studies to date support the idea that neurotrophins may regulate some immune functions. They also play an important role in the development of the thymus and in the survival of thymocytes.     

LC-NMR-MS in drug discovery

Nuclear magnetic resonance spectroscopy (NMR) is arguably the most versatile analytical platform for complex mixture analysis. Specifically, interfacing liquid chromatography with parallel NMR and mass spectrometry (LC-NMR-MS) gives comprehensive structural data on metabolites of novel drugs in development. Applications in natural product, combinatorial chemistry and drug metabolism studies are reviewed. Microcoil probes and capillary separation methods have enormous potential. Recent innovations to improve NMR detection limits include CryoFlowProbes and on-line solid-phase extraction (LC-SPE-NMR). These state-of-the-art analytical platforms are widely applicable to identifying novel candidate drugs from diverse complex mixtures within a drug discovery strategy.     

Fractalkine mediates natural killer-dependent antitumor responses in vivo

CX3CR1 has been described previously as a marker of human cytotoxic effector cells. We evaluated the possibility of using its ligand, CX3CL1, to redirect immune response against tumors. When murine lymphoma cell lines (EL4 and its derivative EG7) stably transfected with human-CX3CL1 were injected s.c. into C57BL/6 mice, the tumor growth was severely impaired when compared with the growth of control cell lines. This antitumor effect of CX3CL1 was also found in T- and B-cell-deficient Rag1-/- mice but vanished in natural killer (NK) cell-deficient beige mice and in CX3CR1-/- mice, suggesting the involvement of CX3CR1-expressing NK cells. In addition, increased NK cell infiltration was observed in CX3CL1-producing tumors compared with controls. The effect of CX3CR1 on tumor growth required host cytotoxic effector cell functions because both IFNgamma-/- and perforin-/- mice were resistant to CX3CL1 antitumor effect. Finally, intratumoral injection of DNA plasmid coding for a chimeric immunoglobulin presenting the CX3CL1 chemokine domain provided strong antitumor activity. Together, these data demonstrate that the CX3CL1 can reduce incidence and size of lymphoma in vivo through increased recruitment of activated NK cytotoxic cells. These findings offer the first evidence of the potential of chimeric immunoglobulin-chemokines in anticancer therapy.