The B/C gene of simian virus 40.

Temperature-sensitive B, C, and BC mutants of Simian virus 40 (SV40) map in the late region of the viral genome inHin fragments K, F, J, and G, a DNA segment of about 1200 nucleotide pairs (Lai, C.-J., and Nathans, D. (1975)Virology 66, 70–81). To define the B/C region further, mutants of SV40 with deletions in this genomic segment were constructed by enzymatic excision of DNA from the viral genome, followed by cloning in the presence of a complementing tsA mutant of SV40. After localization of deleted genome segments by analysis of endo R fragments and electron microscopic heteroduplex mapping, selected deletion mutants were tested for complementation by ts mutants and were screened for their ability to produce new viral proteins in infected cells. Complementation tests indicated that B/C deletion mutations are in a cistron distinct from that of tsA and tsD mutations and that the junction between the B/C and D genes is within Hin-K. Two of the deletion mutants produced new proteins detectable in infected cells. More detailed analysis of one of these proteins (of molecular weight 25,000) indicated that it precipitated with antiserum against dissociated SV40 capsids, and that all but one of its lysine-containing tryptic peptides cochromatographed with SV40 VP1 tryptic peptides. We conclude that the B/C gene, containing approximately 1200 nucleotide pairs, codes for VPl. Since deletion mutants lacking Hin-E do not complement B mutants, we suggest that the Hin-E DNA segment has a signal required for expression of the B/C gene.     

Pulmonary artery angiosarcoma: a clinicopathologic and radiological correlation

A 69-year-old man presented with cough, shortness of breath, and fatigue. He was initially treated for allergies and then for pulmonary embolism. Radiologically, a tumor mass was found to occlude the right pulmonary artery and involve the pulmonary trunk. A right pneumonectomy was performed. Histologically, a cellular malignant spindle and epithelioid tumor with areas of necrosis and brisk mitotic activity was seen. In some areas, the tumor appeared to form vascular channels. Focal osteosarcomatous differentiation was present. Immunohistochemical studies were performed including vimentin, smooth muscle actin, desmin, CD31, CD34, S100, and pan-cytokeratin. The tumor cells were positive for CD31 and vimentin and negative for pan-cytokeratin, CD34, and S100. Two months after surgery, the patient was alive and well.     

Human papillomavirus typing with a polymerase chain reaction-based genotyping array compared with type-specific PCR

BACKGROUND: Type-specific persistence of human papillomavirus (HPV) infection can cause invasive cervical cancer. OBJECTIVES: To evaluate the efficacy of HPV detection and typing with a general polymerase chain reaction (PCR)-based genotyping array and to compare it with a type-specific PCR assay. STUDY DESIGN: Four hundred and thirty-three cervical samples were tested with a modified MY11/GP6+ PCR-based reverse-blot assay (EasyChip HPV Blot; King Car, Taiwan [hereafter HPV Blot]) and with 20 genotypes of L1-type-specific PCR (HPV-6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -53, -56, -58, -59, -62, -66, -68, -70, and -71 [CP8061]). RESULTS: The concordance of the two tests in determining HPV positivity was 96.8% (419/433), with a Cohen's kappa=0.93 (95% CI: 0.90-0.97) and McNemar's test of P=1.0, which indicates excellent agreement. The overall concordance of the two tests in the identification of type-specific HPV was 91.0% (394/433). Sensitivity (90-100%), specificity (99.2-100%), and accuracy (98.6-100%) rates of HPV Blot against the gold standard were satisfactory for HPV-16, -18, -58, -33, -52, -39, -45, -31, -51, -70 while HPV-71 (63.6%) had suboptimal sensitivity. Though the kappa values between the two tests for many individual genotypes could not be reliably calculated because of low positivity, the kappa values for HPV-16, -52, and -58 were excellent (0.93, 0.96, and 0.95, respectively). CONCLUSION: The modified MY11/GP6+ PCR-based HPV Blot assay is accurate and sensitive for detection and genotyping of HPV in cervical swab samples.     

Serum immunoglobulin levels in various skin diseases

Serum immunoglobulin (IgG, IgA, IgM) determinations by the single radial immunodiffusion technique were done in patients with various skin diseases. The geometric means of the IgG, IgA and IgM concentrations of each of the patient groups were compared with those of a control group comprising 156 individuals.

A significantly raised IgG level was found only in patients with pemphigus; in patients with dermatitis herpetiformis, other eczemas, and psoriasis vulgaris the IgG level was significantly lowered. The IgA level was significantly elevated in patients with discoid lupus erythematosus and (bullous) pemphigoid, and the IgM level was significantly depressed in patients with atopic dermatitis.

IgE determinations, done with the Ouchterlony technique in a selected group of patients, showed raised levels in some patients with malignant reticulosis and other eczemas but not in those with atopic dermatitis.

Comparison of the results of the serum immunoglobulin determinations with the immunoglobulin synthesis of lesional skin showed no correlation between the local synthesis of immunoglobulins in the skin and changes in the serum levels.

     

Recombinant hepatitis delta antigen from E. coli promotes hepatitis delta virus RNA replication only from the genomic strand but not the antigenomic strand

Hepatitis delta antigen (HDAg) of hepatitis delta virus (HDV) typically consists of two related protein species. The small HDAg (S-HDAg) is a 24-kDa protein of 195 amino acids and the large HDAg (L-HDAg) is a 27-kDa protein with an additional 19 amino acids at its C-terminus. These two proteins have distinct functions in the HDV life cycle. We have developed conditions for expressing S-HDAg and L-HDAg in E. coli as soluble proteins to facilitate large-scale purification. These proteins were purified to homogeneity and shown to be biologically active. Transfection of the purified recombinant S-HDAg together with HDV genomic RNA resulted in viral RNA replication. Surprisingly, the purified S-HDAg could not initiate replication from the antigenomic-sense HDV RNA, even though the latter led to RNA replication when transfected with an mRNA encoding the S-HDAg. These results suggest that initiation of HDV RNA synthesis from the antigenomic RNA may require a form of HDAg that is modified in mammalian cells; in contrast, RNA synthesis from the genomic RNA could be initiated by the recombinant S-HDAg from E. coli. Interestingly, the purified L-HDAg appeared as multiple protein species, including one corresponding to S-HDAg, probably as a result of degradation. The partially proteolyzed L-HDAg also initiated HDV RNA replication under the same conditions. These results add to the mounting evidence that genomic- and antigenomic-strand HDV RNA syntheses are carried out by different mechanisms.     

Conformation and gas permeability of poly(α-amino acid) membranes

The permeability of some poly(?-amino acid) (PAA) membranes like such of poly(N,δ-carbobenzoxy-L -lysine) (PCBL), poly(N,δ-carbobenzoxy-L -ornithine) (PCBO) as well as of copolymers of L -lysine and carbobenzoxy-L -lysine to oxygen and carbon dioxide were determined at different water content especially with regard to their use for artificial lungs. The conformations of these polymer membranes were studied by means of IR-spectra and X-ray diffraction. The results on the diffusion coefficient obtained for PCBL and PCBO were analysed in terms of Eyring's theory. They suggest that the microvoids in the interstices between the α-helices, assumed on the basis of X-ray analyses, play an important role, especially below the glass transition temperature T_g of the side-chains. This seems also to contribute partly to the diffusion of gas through the membrane even above T_g and results in an abnormally high “apparent activation energy” of diffusion in the wet state below T_g. It was found that the permeability of the membrane of partially decarbobenzoxylated PCBL for oxygen in a certain temperature range is higher than that for carbon dioxide. This has never been observed for any other synthetic polymer, because usually carbon dioxide has a higher solubility in these materials than oxygen. In the case of the partially decarbobenzoxylated PCBL membranes, however, the diffusion coefficient of carbon dioxide, and therefore the permeation of this gas, decreases much more than that of oxygen with increasing decarbobenzoxylation accompanied by the formation of β-structure and concomitantly the formation of intermolecular hydrogen bonds. Obviously, this phenomenon may be responsible for the permselectivity of these membranes for oxygen compared with carbon dioxide.     

Effects of low-level microwave irradiation on amphetamine hyperthermia are blockable by naloxone and classically conditionable

In a series of experiments, we investigated the effects of pulsed low-level microwave irradiation on amphetamine-induced hyperthermia in the rat. Rats were irradiated in a 2,450-MHz cylindrical waveguide exposure system at 1 mW/cm², 2 s pulses, 500 pps, average SAR of 0.6 W/kg. Acute (45 min) exposure to microwaves attenuated amphetamine-induced hyperthermia. This effect was blocked by pretreatment of the animals with the narcotic antagonist naloxone. In another experiment, rats were subjected to ten daily sessions of microwave exposure (45 min/session). On day 11, amphetamine-induced hyperthermia was studied in the animals immediately after a session of either microwave or sham exposure. Similar to the acute effect, amphetamine-induced hyperthermia was attenuated in rats irradiated with microwaves (unconditioned effect). In the sham-irradiated animals we observed a potentiation of the amphetamine-induced hyperthermia, which was a conditioned effect of microwaves. Thus, the conditioned effect (potentiation) was opposite in direction to the unconditioned effect (attenuation). No tolerance developed to the unconditioned effect after subchronic exposure. Furthermore, both conditioned and unconditioned effects of microwaves on amphetamine-induced hyperthermia could be blocked by treatment with naloxone. These data suggest that (1) microwave irradiation may activate endogenous opioids, which in turn alter the actions of psychoactive drugs, and (2) the effect of microwaves on drug action can be classically conditioned. Offprint requests to: H. Lai