Morphogenesis of the fibrous sheath in the marsupial spermatozoon

The spermatozoon fibrous sheath contains longitudinal columns and circumferential ribs. It surrounds the axoneme of the principal piece of the mammalian sperm tail, and may be important in sperm stability and motility. Here we describe its assembly during spermiogenesis in a marsupial, the brush-tail possum, and compare its structural organization with that of eutherian mammals, birds and reptiles. Transmission electron microscopy showed that possum fibrous sheath assembly is a multistep process extending in a distal-to-proximal direction along the axoneme from steps 4 to 14 of spermiogenesis. For the most part, assembly of the longitudinal columns occurs before that of the circumferential ribs. Immunohistochemical and immunogold labelling showed that fibrous sheath proteins are first present in the spermatid cytoplasm; at least some of the proteins of the sheath precursors differ from those in the mature fibrous sheath. That immunoreactivity develops after initiation of chromatin condensation suggests that fibrous sheath proteins, or their mRNAs, are stored within the spermatid cytoplasmic lobule prior to their assembly along the axoneme. These findings are similar to those in laboratory rats, and thus suggests that the mode of fibrous sheath assembly evolved in a common ancestor over 125 million years ago, prior to the divergence of marsupial and eutherian lineages.     

In vitro evaluation of the mutagenic and carcinogenic power of high purity zirconia ceramic

Tetragonal zirconia polycrystal (TZP) is a new interesting ceramic for the manufacture of medical devices. Its wide use in orthopedic and odontoiatric implants was limited till now by the high chemical and radiochemical impurities of the raw materials. Purification processes now available allow to obtain high purity ceramic grade powders suitable for TZP ceramics manufacture, even if their possible mutagenic and transforming effects are still unclear. The aim of this work is to study in vitro the mutagenic and oncogenic effects of a new zirconia ceramic stabilized by yttria (Y-TZP). This ceramic was sintered from high purity powders obtained by a process developed under a project carried out within the Brite EuRam programme. For comparison, ceramics made from unpurified zirconia powder were also tested. Fibroblasts irradiated by a linear accelerator were used as positive control. The results obtained show that Y-TZP ceramic does not elicit either mutagenic or transforming effect on C3H/10T(1/2) (10T(1/2)) cells and demonstrate that ceramic from high purity powders can be considered suitable for biomedical applications from the point of view of the effects of its radioactive impurity content.     

Aberrant interleukin (IL)-4 and IL-5 production in vitro by CD4+ helper T cells from atopic subjects.

The cytokine secretion profiles of T cell lines (TCL) specific for purified protein derivative (PPD) or streptokinase (SK), contemporarily derived from nine atopic and nine nonatopic individuals, were compared. Upon stimulation with phorbol myristate acetate (PMA) plus anti-CD3 monoclonal antibody (mAb), all TCL from both atopics and nonatopics produced interleukin (IL)-2 and interferon (IFN)-gamma. The mean IL-2 production by PPD- or SK-specific TCL from both atopics and nonatopics was similar, whereas the mean IFN-gamma production by TCL derived from atopics was significantly lower. In addition, both PPD- and SK-specific TCL from atopics produced detectable amounts of IL-4 and IL-5, whereas the corresponding TCL derived from nonatopics did not. A total number of 107 and 99 PPD-specific CD4+ T cell clones (TCC) were then derived from TCL of 4 atopic and 4 nonatopic donors and assessed for their profile of cytokine production in response to stimulation with either PMA plus anti-CD3 mAb or the specific antigen. Under both these experimental conditions, virtually all PPD-specific TCC from both atopic and nonatopic individuals produced IL-2 and IFN-gamma. In contrast, the great majority of PPD-specific TCC derived from nonatopic individuals did not produce IL-4 and IL-5, whereas high proportions of PPD-specific TCC derived from atopic donors displayed the ability to produce noticeable amounts of IL-4 and IL-5 besides IL-2 and IFN-gamma. These data indicate that CD4+ T cells from atopic individuals are able to produce IL-4 and IL-5 in response to bacterial antigens, such as PPD and SK, that usually evoke responses with a restricted type-1 T helper (Th1)-like cytokine profile in nonatopic individuals. Aberrant IL-4 production by Th cells may represent one of the immune alterations responsible for enhanced IgE antibody production in atopic people.     

Searching for Wolbachia (Rickettsiales: Rickettsiaceae) in mosquitoes (Diptera: Culicidae): large polymerase chain reaction survey and new identifications

Bacteria of the genus Wolbachia constitute a group of intracellular and maternally inherited micro-organisms that are widespread in arthropods, inducing several reproductive disorders such as cytoplasmic incompatibility in their hosts. Considering relevant biological implications related to the presence of Wolbachia in several insect orders, for example its potential role as mechanism for rapid speciation and as vehicle to drive genetic markers in wild populations of vectors of medical and veterinary interest, we carried out an extensive polymerase chain reaction survey to detect Wolbachia in several species of mosquito belonging to genera involved in the transmission of pathogens. Five species out of 26 tested have shown to be infected; for four of them this is the first evidence of the Wolbachia infection. A phylogenetic analysis was also performed, positioning the five Wolbachia strains in the phyletic subdivision B.     

Free Fatty Acids Signature in Human Intestinal Disorders: Significant Association between Butyric Acid and Celiac Disease

Altered circulating levels of free fatty acids (FFAs), namely short chain fatty acids (SCFAs), medium chain fatty acids (MCFAs), and long chain fatty acids (LCFAs), are associated with metabolic, gastrointestinal, and malignant diseases. Hence, we compared the serum FFA profile of patients with celiac disease (CD), adenomatous polyposis (AP), and colorectal cancer (CRC) to healthy controls (HC). We enrolled 44 patients (19 CRC, 9 AP, 16 CD) and 16 HC. We performed a quantitative FFA evaluation with the gas chromatography–mass spectrometry method (GC–MS), and we performed Dirichlet-multinomial regression in order to highlight disease-specific FFA signature. HC showed a different composition of FFAs than CRC, AP, and CD patients. Furthermore, the partial least squares discriminant analysis (PLS-DA) confirmed perfect overlap between the CRC and AP patients and separation of HC from the diseased groups. The Dirichlet-multinomial regression identified only strong positive association between CD and butyric acid. Moreover, CD patients showed significant interactions with age, BMI, and gender. In addition, among patients with the same age and BMI, being male compared to being female implies a decrease of the CD effect on the (log) prevalence of butyric acid in FFA composition. Our data support GC–MS as a suitable method for the concurrent analysis of circulating SCFAs, MCFAs, and LCFAs in different gastrointestinal diseases. Furthermore, and notably, we suggest for the first time that butyric acid could represent a potential biomarker for CD screening.     

Cow’s Milk Protein Allergy as a Model of Food Allergies

Cow’s milk allergy (CMA) is one of the most common food allergies in infants, and its prevalence has increased over recent years. In the present paper, we focus on CMA as a model of food allergies in children. Understanding the diagnostic features of CMA is essential in order to manage patients with this disorder, guide the use of an elimination diet, and find the best moment to start an oral food challenge (OFC) and liberalize the diet. To date, no shared tolerance markers for the diagnosis of food allergy have been identified, and OFC remains the gold standard. Recently, oral immunotherapy (OIT) has emerged as a new therapeutic strategy and has changed the natural history of CMA. Before this, patients had to strictly avoid the food allergen, resulting in a decline in quality of life and subsequent nutritional, social, and psychological impairments. Thanks to the introduction of OIT, the passive approach involving rigid exclusion has changed to a proactive one. Both the heterogeneity in the diagnostic process among the studies and the variability of OIT data limit the comprehension of the real epidemiology of CMA, and, consequentially, its natural history. Therefore, well-planned randomized controlled trials are needed to standardize CMA diagnosis, prevention, and treatment strategies.     

Nongastrointestinal mucosa-associated lymphoid tissue (MALT) lymphomas: Clinical and therapeutic features of 24 localized patients

Background: Peripheral B-cell lymphoma of the marginal zone (MALT, low-grade), presenting as localized, extranodal disease, usually affects the elderly. The gastrointestinal tract is the most frequently involved extranodal location, representing 70% of all MALT lymphomas. Recently, numerous other extranodal sites involved by MALT lymphomas have also been described.Patients and methods: From January 1990 to October 1995, 24 patients with untreated nongastrointestinal low-grade MALT lymphoma were submitted to treatments ranging from the local approach of radiotherapy and local -interferon (-IFN) administration to chemotherapy. The tumours were located in the lung (seven cases), conjunctiva (four cases), lachrymal gland and orbital soft tissue (four cases), salivary glands (three cases), skin (three cases), breast (two cases)' and thyroid (one case). All patients had low-grade stage IE tumours.Results: Chemotherapy was administered in 11 patients (six with lung, three with salivary gland, one with breast, and one with thyroid locations); radiation therapy was employed in seven patients (three with lachrymal gland, three with skin, and one with breast locations); local -IFN administration was administered in five patients (four with conjunctival, and one with lachrymal gland sites); and surgery was employed in one patient with a lung tumour. All patients achieved complete remissions; three local recurrences and two relapses in other sites were observed. The global five-year survival rate was 100% with a relapse-free survival rate of 79%.Conclusions: These data confirm the significant efficacy of different therapeutic approaches to specific sites inbes obtaining a good remission rate for nongastrointestinal localized low-grade MALT lymphomas.     

Arachidonic acid modulates [14C]stearic acid incorporation into phosphatidylinositol,in human neuroblastoma cells

In the human neuroblastoma cell line SK-N-BE(2), arachidonic acid (AA), supplied in the medium at micromolar concentrations, markedly ehnanced [¹⁴C]stearic acid (SA) (but not [¹⁴C]palmitic acid or [¹⁴C]oleic acid) incorporation into phosphatidylinositol (PtdIns). AA failed to stimulate [¹⁴C]SA incorporation into PtdIns precursors, namely phosphatidic acid and cytidinediphosphodiacylglycerol; furthermore, enhanced [¹⁴C]SA incorporation, brought about by exogenously administered AA, was not restricted to PtdIns tetraenoic species. When cells were pulsed for 1 h with [¹⁴C]SA (either in the presence or absence of AA) and then reincubated in AA- and [¹⁴C]SA-free medium, a marked loss of radioactivity from PtdIns was observed, that however was restricted to molecular species other than tetraenoic. These results are discussed in the light of possible mechanisms through which PtdIns achieves the 1-stearoyl-2-arachidonoyl configuration.     

Autosomal recessive hypermyelinating neuropathy

We studied three patients from two kinships, affected by early onset hereditary motor and sensory neuropathy with probable autosomal recessive inheritance (HMSN type III). Morphological studies of sural nerve biopsies revealed an abnormal myelin proliferation. Two adult patients with long-term follow up, lost ability to walk at 28 and 22 years and showed severe involvement of the cranial nerves. Our observations suggest that hypermyelination neuropathy with early onset is a progressive disease with poor long-term prognosis. In one kinship the occurrence of the disease in two sibs of both sexes but not in parents, is consistent with an autosomal recessive inheritance. Familial cases of hypermyelination neuropathy have not been described in previous reports. Morphological aspects of this condition are compared with other forms of hypermyelination neuropathy.Supported by Telethon-Italy for the project: Chronic inflammatory polyradiculoneuropathy: electrophysiological and immunopathological studies     

Autoradiographic localization of dopamine D2-like receptors in the rabbit pulmonary vascular tree

In the present study, the pharmacological characteristics and the anatomical localization of dopamine D₂-like receptor sites in the extraparenchymal and in the intraparenchymal portion of the rabbit pulmonary artery were investigated using combined radioligand binding and light microscope autoradiography with [³H]-spiroperidol (spiperone) as a ligand. The ligand was bound to sections of the pulmonary artery in a manner consistent with the labelling of dopamine D₂-like receptors with an equilibrium dissociation constant (K _d) of about 2.4±0.07 nmol/l and a maximum density of binding sites of 65±4.5 fmol/mg tissue. In contrast, binding experiments made with sections of rabbit lung did not allow the evaluation of specific binding. Light microscope autoradiography showed the development of specific silver grains within the tunica adventitia of extraparenchymal branches of rabbit pulmonary artery and of large and, to a lesser extent, of medium-sized intraparenchymal branches of the pulmonary artery. No silver grains were found within small branches of the pulmonary artery or of the pulmonary vein. Development of adventitial silver grains was inhibited by compounds active at dopamine receptors. The greater sensitivity to displacement by domperidone, haloperidol, (–)-sulpiride and bromocriptine than to displacement byN-propyl-norapomorphine, quinpirole or clozapine suggests that the [³H]-spiroperidol binding sites observed in extraparenchymal, large and medium-sized branches of the pulmonary artery belong, probably, to the dopamine D₂ receptor subtype. The possible pre-junctional localization of these sites is discussed. Correspondence to: R Amenta