Marco Melis

Transplacental transmission of human polyomavirus BK

The presence of BK virus (BKV) and JC virus (JCV) in autopsy materials (placenta, brain, and kidney) of aborted fetuses was investigated by PCR using two sets of primers, specific for the regulatory region (RR) and for the capsid protein VP1, respectively. The RR of BKV was detected in 12 samples of placenta and brain and in nine samples of kidney obtained from 15 fetuses. Out of the 12 positive cases, four placentas, one brain, and three kidney samples also showed the presence of BKV DNA in the VP1 region. Of 12 placentas from a control group with a normal pregnancy outcome, the RR of BKV was detected in six samples, four of which were also positive for the VP1 region. None of the samples from either group was positive for the RR of JCV. In two cases, the nucleotide sequence of the BK RR demonstrated that the viruses isolated from maternal and fetal tissues showed a high homology with one another and had a characteristic deletion of the R63 box compared to the archetype strain. The results indicate that BKV may be transmitted vertically. J. Med. Virol. 56:372–376, 1998.

Oral focal mucinosis of the Tongue

Oral focal mucinosis (OFM) is an uncommon clinicopathological entity which is considered to be the oral counterpart of cutaneous focal mucinosis and cutaneous myxoid cyst. It is comprised of a clinically elevated mass with a histological feature of localised areas of myxomatous connective tissue. The present study adds a rare case of OFM of the tongue to the literature, and we present a review of the most characteristic oral myxomatous lesions.

Ochronotic arthropathy: structural and ultrastructural features.

Fragments of articular cartilage and synovial membrane in a case of ochronosis were studied by light microscopy (LM), polarized light, and transmission electron microscopy (TEM). Granular and/or shard-shaped pigments were observed in the synovia, cartilage, and subchondral tissue, and dispersed pigment was also seen in the synovial fluid. Zones of the articular cartilage surface showed small erosions near shards, and sometimes, when the degenerative process was in an advanced stage, a substitutive fibrosis of the cartilage edge was demonstrated. LM and TEM observations of the samples studied revealed an alteration of collagen fibrils that appeared wavy and sometimes fragmented with loss of periodicity. They were always mixed with the dispersed pigment. A peculiar finding that characterized this ochronotic case was the complete absence of inflammatory infiltrates or signs of monocyte-macrophage activation. These structural and ultrastructural observations suggest that the pigment deposition in the articular surfaces was due to the synovial fluid circulation and partially to subchondral blood flow, which transports and stores the ochronotic pigments in the synovia and cartilage. These etiopathologic elements associated with the mechanical pathogenesis naturally present in the joints can contribute to the explanation of the pathogenesis and origin of ochronotic arthropathy.

Tenascin Expression in Elastotic Cuffs of Invasive Ductal Carcinoma of the Breast

We studied immunohistochemically one thousand one hundred and thirty-seven cases of primary invasive breast cancers (NST) and adjacent normal mammary glands for tenascin expression, and compared their elastic content to verify if a relationship exists between tenascin expression and elastosis. Periductal, perivascular and stromal elastosis were graded on a scale from 0 to 3 (absent to massive). All carcinomas showed tenascin expression and elastosis with various histological appearances. In the adjacent breast, teanscon was distributed around the normal ducts or with extasia and uctal hyperplasia without atypia. Digestion of the sections with elastase prior to staining resulted in a loss of the specific staining reactions in all areas where elastosis was present. Tenascin staining was observed in the mesenchyme closely surrounding the neoplastic ducts and the cancer cell nests. Stromal tenascin staining appeared stronger in those carcinomas that exhibited marked desmoplastic reactions. The highly differentiated tumours contained more elastosis in their tumour tissue than the poorly differentiated ones, whereas tenascin expression was stronger in poorly differentiated tumours than well differentiated tumours. A strong staining for tenascin was observed in the elastotic cuff. Tenascin staining did not disappear afterwards with elastase. We did not find a statistically significant correlation between tenascin expression, elastosis and prognostic factors such as size of the tumour, lymph node metastasis, tumour necrosis and age. In our study tenascin proved to be an additional element in elastotic areas even though the significance of an association between elastosis and tenascin is still unknown, as is that of elastosis itself.

Columnar cells of the parietal layer of Bowman's capsule and their relationship with the sexual cycle in normal female mice

The tubule-like cells (TLC) are present also in the parietal layer of the Bowmans capsule of the renal corpuscles in normal female mice kidney. These cells are morphologically similar to the cells of the proximal convoluted tubule. Further, significant variations of the TLC were present according to the phase of the sexual cycle.

Ablation of hard dental tissues by ArF and XeCl excimer lasers

The paper investigates the effects of UV laser irradiation on hard dental tissues. 12 sagittal cross sections 1 mm thick of teet extracted have been irradiated with pulsed ArF (A.=193 nm) and XeCl (A.=308 nm) excimer lasers. The beam has been focused to obtain a spot of about 1 mm on the enamel and dentin of the teet. The depth and the internal profile of the holes have been measured with a profilometer and correlated with the number of pulses and beam energy for each wavelength. No cracks were induced by thermal stresses nor preferential concentrations of Ca and F have been evidenced on the enamel and dentin after UV irradiation. These results show that the ablation of hard dental material can be successfully carried out with excimer laser irradiation without heat damage of the underlying tissues.