Non-fatal massive right atrial thrombus associated with Hickman catheter in an adult receiving chemotherapy for acute leukaemia

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Epithelial ovarian cancer complicating renal transplantation

Patients taking immunosuppressive therapy are at substantial risk for malignant disease. We report two cases of epithelial ovarian cancer occurring in women after renal transplantation with subsequent poor clinical outcome. Clinicians are advised to thoroughly investigate adnexal masses in this patient population.

Membrane anchoring domain of herpes simplex virus glycoprotein gB is sufficient for nuclear envelope localization

We have used the glycoprotein gB of herpes simplex virus type 1 (gB-1), which buds from the inner nuclear membrane, as a model protein to study localization of membrane proteins in the nuclear envelope. To determine whether specific domains of gB-1 glycoprotein are involved in localization in the nuclear envelope, we have used deletion mutants of gB-1 protein as well as chimeric proteins constructed by replacing the domains of the cell surface glycoprotein G of vesicular stomatitis virus with the corresponding domains of gB. Mutant and chimeric proteins expressed in COS cells were localized by immunoelectron microscopy. A chimeric protein (gB-G) containing the ectodomain of gB and the transmembrane and cytoplasmic domains of G did not localize in the nuclear envelope. When the ectodomain of G was fused to the transmembrane and cytoplasmic domains of gB, however, the resulting chimeric protein (G-gB) was localized in the nuclear envelope. Substitution of the transmembrane domain of G with the 69 hydrophobic amino acids containing the membrane anchoring domain of gB allowed the hybrid protein (G-tmgB) to be localized in the nuclear envelope, suggesting that residues 721 to 795 of gB can promote retention of proteins in the nuclear envelope. Deletion mutations in the hydrophobic region further showed that a transmembrane segment of 21 hydrophobic amino acids, residues 774 to 795 of gB, was sufficient for localization in the nuclear envelope. Since wild-type gB and the mutant and chimeric proteins that were localized in the nuclear envelope were also retained in the endoplasmic reticulum, the membrane spanning segment of gB could also influence retention in the endoplasmic reticulum.

Perinatal outcome in pregnancies complicated by pulmonary tuberculosis

OBJECTIVES

To assess the perinatal outcome of pregnancies complicated by active pulmonary tuberculosis.

METHODS

The perinatal outcome of 79 gravidas with pulmonary tuberculosis was compared with that of 316 normal gravidas of similar age, parity and socioeconomic status.

RESULTS

The mean birthweight of infants (2649 g) born to tuberculous mothers was 215 g less than that of control group (P < 0.001). Pulmonary tuberculosis was associated with an approximate 2-fold increase in prematurity (22.8% vs. 11.1%, P < 0.01), small for gestational age (20.2% vs. 7.9%, P < 0.005) and low birthweight neonates (34.2% vs. 16.5%, P < 0.001), and 6-fold increase in perinatal deaths (10.1% vs. 1.6%, P < 0.001). The adverse perinatal outcome was pronounced in cases with late diagnosis, incomplete and irregular treatment, and advanced pulmonary lesions.

CONCLUSIONS

Maternal tuberculosis is a high-risk perinatal condition. The study emphasizes the need for early diagnosis and treatment of tuberculosis, preferably before pregnancy, regular medical supervision and good perinatal care for tuberculous mothers.

Evaluation of some properties of a phosphorodithioate oligodeoxyribonucleotide for antisense application

An all phosphorodithioate oligodeoxyribonucleotide (PS2; 17-mer) complementary to the coding region of the rabbit beta-globin mRNA was compared with the normal (PO2) and phosphorothioate (POS) oligonucleotide of the same size and sequence with respect to physicochemical properties and antisense activity in cell-free systems. The melting temperature (Tm) of the PS2-cDNA duplex was reduced by 17 degrees C relative to the PO2-cDNA duplex, compared to 11 degrees C for the POS-cDNA duplex, suggesting a decreased stability of the duplex with an increasing sulfur substitution. Like the POS-derivative, the PS2 oligonucleotide is quite stable against exonucleases, but these modified oligonucleotides showed different stability towards endonucleases and also towards different sub-cellular fractions of MCF-7 cells. During in vitro protein binding studies, the PS2 oligonucleotide showed similar binding (10-20%) to that of the PO2 oligonucleotide, while the POS oligonucleotide bound 60%. In cell-free translation, the PS2 oligonucleotide produced slightly higher specific translation inhibition of rabbit beta-globin mRNA compared to that of the PO2 oligonucleotide, and this was true only at concentration below 2 mM. The POS-derivative, except at 10 mM concentration, always showed higher translation arrest of the rabbit beta-globin mRNA compared to that of the other two oligonucleotides. The present study suggests that the PS2 oligonucleotide offers very little advantage over the POS oligonucleotide for use as an antisense analog.

Aberrant CD8 antigen expression in a patient with B chronic lymphocytic leukaemia showing unusual disease progression

Co-expression of T cell antigens in B-CLL has been well recognized. The commonest T cell antigen known to be expressed in B-CLL is CD5, and recent reports suggest that CD5 expression is associated with good prognosis. Expression of CD8 antigen, however, is much less common with uncertain prognostic significance. We report a case of B-CLL with aberrant CD8 expression, who had unusual disease progression with a fatal outcome.

Effects of deletions in the carboxy-terminal hydrophobic region of herpes simplex virus glycoprotein gB on intracellular transport and membrane anchoring

The gB glycoprotein of herpes simplex virus type 1 is involved in viral entry and fusion and contains a predicted membrane-anchoring sequence of 69 hydrophobic amino acids, which can span the membrane three times, near the carboxy terminus. To define the membrane-anchoring sequence and the role of this hydrophobic stretch, we have constructed deletion mutants of gB-1, lacking one, two, or three predicted membrane-spanning segments within the 69 amino acids. Expression of the wild-type and mutant glycoproteins in COS-1 cells show that mutant glycoproteins lacking segment 3 (amino acids 774 to 795 of the gB-1 protein) were secreted from the cells. Protease digestion and alkaline extraction of microsomes containing labeled mutant proteins further showed that segment 3 was sufficient for stable membrane anchoring of the glycoproteins, indicating that this segment may specify the transmembrane domain of the gB glycoprotein. Also, the mutant glycoproteins containing segment 3 were localized in the nuclear envelop, which is the site of virus budding. Deletion of any of the hydrophobic segments, however, affected the intracellular transport and processing of the mutant glycoproteins. The mutant glycoproteins, although localized in the nuclear envelope, failed to complement the gB-null virus (K082). These results suggest that the carboxy-terminal hydrophobic region contains essential structural determinants of the functional gB glycoprotein.

An outbreak of echovirus type 4 infections and its implications for diagnosis and management in general practice

Altogether, 133 patients with Echovirus type 4 infection were studied. Presenting illnesses and reasons for referral to hospital were analyzed. The reason for admission was commonly concern about meningitis, but also an unexplained rash or sore throat. More research is needed in general practice in order to clearly elucidate the spectrum of disease caused by Echoviruses.

Characterization of the human L-plastin gene promoter in normal and neoplastic cells

Plastins are a family of human actin-binding proteins (isoforms) which are abundantly expressed in all normal replicating mammalian cells. One isoform, L-plastin, is constitutively expressed at high levels in hemopoietic cell types while T-plastin is constitutively expressed in all non-hemopoietic cells of solid tissues that have replicative potential (fibroblasts, endothelial cells, epithelial cells, melanocytes, etc.). L-plastin is, however, constitutively synthesized in many types of malignant human cells of solid tissues suggesting that its expression is induced during tumorigenesis. The frequency of L-plastin induction in some cancers of the steroid-regulated female reproductive tract (breast, ovary, uterus, and placenta) appears to be especially high (79% in a limited survey). To learn the mechanism of L-plastin gene activation accompanying tumorigenesis, we have begun to characterize the promoter and regulatory elements of the L-plastin gene. Transcription initiation from this promoter was found to occur at multiple sites and as near as 10 base pairs from the 3'-side of the TATAAA box. The promoter and its flanking DNA were cloned and sequenced to identify potential regulatory elements that participate in the induction of the L-plastin gene in neoplastic cells. Examination of upstream sequences revealed the existence of two potential progesterone, one potential estrogen, and four potential Ets-1 responsive elements flanking the promoter. A 315-base pair fragment spanning the TATAAA box and a potential Sp1-binding site exhibited maximum promoter activity using CAT as a reporter while longer promoter fragments extending into upstream flanking sequences spanning the hormone receptor-response elements exhibited reduced promoter activity. An expression vector, pHLPPr-1-neo, was constructed using a 5.1-kilobase pair EcoRI-HindIII fragment of the L-plastin gene that contained the potential upstream regulatory elements, the TATAAA box, and part of the first exon. This promoter could direct the constitutive expression of the reporter beta-galactosidase at high frequency in transfected colonies of transformed cells that express L-plastin constitutively; by contrast, this promoter was virtually inactive in transfected colonies of normal fibroblasts and it exhibited a low frequency of constitutive activation in transfected colonies of in vitro SV40-transformed fibroblasts which did not exhibit L-plastin expression. The utility of this recombinant promoter in determining the mechanism(s) that leads to activation of the L-plastin gene in tumor cells is discussed. The potential significance of regulation of the L-plastin gene by reproductive hormones in cancers arising in hormone-responsive tissues is also discussed.

Phosphorothioate-phosphodiester oligonucleotide co-polymers: assessment for antisense application

Efforts have been made to reduce the disadvantages associated with the natural oligonucleotides (all-PO) for antisense application by introducing phosphorothioate (PS) linkages into the molecule. A series of such oligodeoxynucleotide copolymers (17-mers) complementary to the coding region of the rabbit beta-globin mRNA, and containing different proportions and arrangements of PO and PS bonds, were synthesized and tested for their protein-binding properties, nuclease stability in vitro, hybridizing ability with the complementary DNA (cDNA), ability to form RNase H-sensitive substrates and antisense activity in cell-free systems. The melting temperatures (Tm) of the co-polymers were reduced by up to 6 degrees C relative to the all-PO oligo, compared to 11 degrees C for the all-PS compound, indicating intermediate hybridizing abilities of the co-polymers. The protein-binding studies with human serum albumin exhibited a linear correlation with the percentage of PS linkage present in the molecule. Nuclease susceptibilities of the co-polymers were also improved, but the number and position of the PS linkages played a significant role in such improvement. Translation inhibition by these oligonucleotides was only found in wheat germ agglutinin (WGA) extract, but not in rabbit reticulocyte lysate (RRL) cell-free system, suggesting the involvement of RNase H in their antisense activities. Provided they have > or = 50% PS linkages, the co-polymers produced almost the same increased inhibition in the WGA system as that of the all-PS oligo. The translation arrest in WGA extract is in good agreement with the in vitro cleavage found for rabbit globin mRNA in the oligo:mRNA duplex by RNase H alone. It is concluded that a copolymer of PO and PS might be preferable to either all-PO or all-PS for antisense applications.