Mediastinal hemangioma: radiographic and CT features in 14 patients

PURPOSE: To characterize the imaging features of mediastinal hemangioma. MATERIALS AND METHODS: The authors retrospectively reviewed chest radiographs and computed tomographic (CT) scans from 14 patients with mediastinal hemangioma. RESULTS: Most mediastinal hemangiomas manifested as well-marginated masses at CT. Three masses had punctate calcifications, and one had phleboliths. Five masses were of heterogeneous attenuation at unenhanced CT. Ten of 11 (91%) hemangiomas were of heterogeneous attenuation at contrast material-enhanced CT, and the following four patterns were observed: central (n = 6, 60%), mixed central and peripheral (n = 2, 20%), peripheral (n = 1, 10%), and nonspecific (n = 1, 10%) increased attenuation. Central increased attenuation was observed more frequently after administration of a bolus of contrast material than after slow infusion. CONCLUSION: Hemangiomas should be considered in the differential diagnosis of well-marginated mediastinal masses that have heterogeneous attenuation on CT scans, show central enhancement after administration of contrast material or contain punctate calcification.     

Environmental and personal monitoring of exposure to urban noise and community response

Noise exposure of a population sample living in a city in northern Italy (Genoa) was assessed by measuring the noise in the area as well as with personal sound detectors. Sampling was conducted during a standard day and covered a period of time spent out-of-doors, at work (service sector) and at home. Ambient noise at home and at work was assessed with sound-level meters, personal exposure levels were assessed with personal sound-level/dosimeters. Information regarding each environment was obtained with an interview including also a subjective judgement on traffic intensity and noise levels. The mean individual equivalent continuous sound level (Leq) of recorded noise was 74.5 dB(A) for 24 h and 63.9 dB(A) at night. A further distinction was made between noise exposure at home (Leq 74.4), work (Leq 74.0) and during city transfers (Leq 79.3). Leq values for individual hours, Leq daytime (Leq, d), Leq nighttime (Leq,n) and Leq day-night (Ldn) indices calculated in the different environments, i.e. at work, home and out-of-doors, are reported here. Individual noise levels have then been compared with environmental data and with subjective noise exposure judgement.     

Relationship among hormonal treatments, suppression of spermatogenesis, and testicular protection from chemotherapy-induced damage

To further elucidate the mechanism by which hormonal pretreatment protects the rat testis from damage by procarbazine, we investigated the relationship between the suppression of hormone levels and spermatogenesis and the recovery of spermatogenesis from stem spermatogonia. LBNF1 rats were implanted with capsules containing testosterone or testosterone plus estradiol. After hormone treatment, rats were injected with procarbazine, and recovery of spermatogenesis was assessed. Testosterone (2 cm) plus estradiol (0.5-cm) reduced serum LH levels causing intratesticular testosterone (ITT) to fall to 3% of control levels within 2 weeks, but testis weights and sperm head counts were not appreciably suppressed until 4 weeks. Two weeks' hormone pretreatment, only slightly enhanced spermatogenesis recovery, but 4 weeks markedly increased it. Testosterone (2 cm) alone produced slower suppression of spermatogenesis and less protection from procarbazine than did testosterone plus estradiol implants, despite equivalent suppression of LH and ITT. Long testosterone implants (24-cm) partially maintained ITT at 14% of control despite undetectable LH levels, prevented any decline in sperm counts, and nearly completely abrogated the protective effect of the hormone treatment. Protection appeared to be best correlated with the testis weight reduction by hormone treatment. Thus, recovery of spermatogenesis after chemotherapy is dependent on the degree of suppression of spermatogenesis caused by the reduction of ITT levels at the time of chemotherapy and likely involves cells, such as the Sertoli cells, that are both androgen-responsive and affected by the numbers of germ cells present.     

Induction of apoptosis by organotin compounds in vitro: neuronal protection with antisense oligonucleotides directed against stannin

Immortalized cell lines and primary neuronal cultures were used to characterize the selective toxicity of trimethyltin (TMT),triethyltin (TET) and tributyltin (TBT). TBT and TET were cytotoxic at similar concentrations in the immortalized cell lines tested; the 50% toxic concentration (TC50) was 1 to 11 microM. In contrast, immortalized cell lines varied considerably in their sensitivity to TMT, with sensitive cell lines (neuroblastomas, T-, B-cell lines) showing TC50 values of 2 to 8 microM, whereas insensitive cells (NIH-3T3 fibroblast, HTB-14 glioma, TC-7 kidney cells) had TC 50 values > 100 microM. Primary neuronal cell cultures were very sensitive to organotins (TC50 values, 1-10nM), and showed patterns of selective toxicity with respect to neuronal and glial cells. Because organotin toxicity evolves over 24 to 48 hr. we determined whether these compounds induced apoptosis in primary cultures. TMT increased (P < .05) the fraction of apoptotic cells 6 and 12 hr after treatment with TMT at TC50 concentrations. Prior studies suggested that a protein, stannin, was localized in cells sensitive to organotins. Stannin was expressed in several TMT-sensitive cell lines (PC12, T, B cells) and in primary neurons in culture. Stannin was absent in the resistant HTB-14 glioma cell line. The role of stannin in mediating TMT toxicity in primary cultures was investigated by blocking stannin expression with specific antisense oligonucleotides. Treatment of primary cultures with antisense oligonucleotides for 48 hr before and during TMT treatment significantly protected neurons from the neurotoxic and apoptotic effects of TMT. This effect was not observed with scrambled oligonucleotide controls. Thus, TMT may induce apoptosis in sensitive cells, which is partly mediated by stannin. Based on the available data we conclude that stannin expression is necessary, but not sufficient for TMT toxicity.     

Hydrocephalus

Hydrocephalus may be an acquired or congenital condition. Clinical signs often reflect the level of brain involvement. In young dogs, the presence of a dome-shaped head and/or persistent fontanel are suggestive of hydrocephalus. Ventriculoperitoneal shunting is often used for definitive treatment of hydrocephalus.     

Immunological properties of plaque purified strains of live attenuated respiratory syncytial virus (RSV) for human vaccine

Respiratory syncytial virus (RSV) causes severe lower respiratory tract disease in infants, young children, and the elderly. Efforts to develop satisfactory live or inactivated vaccines have not yet been proven successful. Our research focuses on the development of four purified live attenuated RSV sub-type A human vaccine clones. Temperature sensitive (ts) and attenuated purified clones of either cold-adapted (ca) RSV or high-passage (hp) RSV were administered intra-nasally (i.n.) to BALB/c mice and tested for immunogenicity. All four clones produced significant anti-RSV F IgG2a and IgG1 titres in the sera of mice, RSV-specific neutralizing titres higher than those produced by their wild-type progenitor viruses, cytotoxic T-lymphocyte (CTL) activity, and total protection against wild-type (wt) viral challenge. These purified vaccine candidates await testing in humans to determine which contain the required balance between immunogenicity and attenuation.     

The complete genomic sequence of an HTLV-II isolate from a Guahibo Indian from Venezuela

A polyclonal CD3(+), CD8(+) T-cell line, G2, was derived from the peripheral blood of a seropositive, PCR-positive, HTLV-IIB infected Guahibo Indian from Venezuela. The cell line is productively infected with HTLV-IIB. The entire HTLV-II G2 proviral DNA was sequenced via PCR using overlapping HTLV-II primer pairs. Phylogenetic analyses indicate that HTLV-II G2 is the most divergent HTLV-IIB strain identified to date. Characterization of its deduced proteins and its relationship to other members of the PTLV/BLV genus of retroviruses are discussed.     

Elements essential for accumulation and function of small nucleolar RNAs directing site-specific pseudouridylation of ribosomal RNAs

During site-specific pseudouridylation of eukaryotic rRNAs, selection of correct substrate uridines for isomerization into pseudouridine is directed by small nucleolar RNAs (snoRNAs). The pseudouridylation guide snoRNAs share a common 'hairpin-hinge- hairpin-tail' secondary structure and two conserved sequence motifs, the H and ACA boxes, located in the single-stranded hinge and tail regions, respectively. In the 5'- and/or 3'-terminal hairpin, an internal loop structure, the pseudouridylation pocket, selects the target uridine through formation of base-pairing interactions with rRNAs. Here, essential elements for accumulation and function of rRNA pseudouridylation guide snoRNAs have been analysed by expressing various mutant yeast snR5, snR36 and human U65 snoRNAs in yeast cells. We demonstrate that the H and ACA boxes that are required for formation of the correct 5' and 3' ends of the snoRNA, respectively, are also essential for the pseudouridylation reaction directed by both the 5'- and 3'-terminal pseudouridylation pockets. Similarly, RNA helices flanking the two pseudouridylation pockets are equally essential for pseudouridylation reactions mediated by either the 5' or 3' hairpin structure, indicating that the two hairpin domains function in a highly co-operative manner. Finally, we demonstrate that by manipulating the rRNA recognition motifs of pseudouridylation guide snoRNAs, novel pseudouridylation sites can be generated in yeast rRNAs.     

Intracerebral Whipple''s disease diagnosed by stereotactic biopsy: a case report and review of the literature

We studied the effects of bile stasis in a guinea pig model of pigment gallstone. The common bile ducts of guinea pigs were partially ligated, and the guinea pigs killed one or two weeks later. Biliary sludge or stones were examined with the Fourier transform infrared spectroscopy and the scanning electromicroscopy. The bile was analyzed for pH, free calcium, bile acids and bilirubin fractions, and the activities of both bacterial and endogenous beta-glucuronidase. After bile duct ligation, calcium bilirubinate precipitates or stones formed in all except one of the animals studied. The bile pH and the proportion of unconjugated bilirubin rose after bile duct ligation, with a concomitant fall of bilirubin monoglucuronide. The activity of bacterial beta-glucuronidase decreased after ligation, while the activity of endogenous beta-glucuronidase rose at week 2. Our results imply that precipitation of calcium bilirubinate in this animal model was induced by an increased bile pH and the nonenzymatic hydrolysis of conjugated bilirubin.