Tumour size and vascular invasion predict distant metastasis in stage I breast cancer. Grade distinguishes early and late metastasis.

BACKGROUND: Recent Dutch guidelines recommend adjuvant systemic treatment (AST) for women with high grade stage I breast carcinoma > or =1 cm. High grade is defined as Bloom and Richardson grade 3 (B&R3), Nottingham modification, or mitotic activity (MAI) > or =10/1.59 mm2. AIMS: To investigate the validity of these histological prognostic factors as the exclusive defining criteria. MATERIALS/METHODS: Fifty patients with stage I breast carcinoma who developed distant metastases and 50 matched controls without metastasis were studied; none had received AST. RESULTS: Cases more often had tumours > or =1 cm (p = 0,019), B&R3 tumours (p = 0.059), grade 3 nuclei (p = 0.005), and vascular invasion (p = 0.007). No differences were found for MAI > or =10 (p = 0.46). In multivariate analysis, the only significant variables were vascular invasion and tumour size (odds ratios: 8.21 and 5.35, respectively). In a separate analysis, the 50 cases were divided into 25 patients with early and 25 with late metastasis. Those with early metastasis more often had B&R3 tumours (p = 0.009) and grade 3 nuclei (p = 0.006). No differences were found for tumours > or =1 cm, vessel invasion, or MAI > or =10. Using the present Dutch guidelines for AST, based on B&R3, 20 cases and 11 controls would have received AST. Based on MAI > or =10, 14 cases and 11 controls would have received AST. CONCLUSIONS: Tumour size and vessel invasion are the best prognostic factors for disease free survival in patients with stage I breast cancer. Dutch selection criteria for AST for these patients need to be improved. Some prognostic factors are time dependent, making their use as selection criteria for AST more complicated.

Hospital volume and post-operative mortality after resection for gastric cancer.

AIMS: In low-volume hospitals, expertise in gastric surgery is difficult to maintain because of the decreasing incidence of gastric cancer and the fall of surgery for ulcer disease. We evaluated the prognostic impact of hospital volume on post-operative mortality (POM) in a consecutive series of 1978 patients. METHODS: Information on patients undergoing resection for gastric cancer in the period 1987-97 was retrieved from the Rotterdam Cancer Registry. The relationship between hospital volume and POM was analysed by logistic regression, adjusting for other prognostic factors. RESULTS: POM was 7.9% on average but varied between the 22 hospitals from 3.1% to 15.1% (P=0.15). Hospital volume had no prognostic influence (P=0.74). Prognostic factors were age (70-79 years odds ratio (OR)=3.8, 80+ years OR=6.0), sex (male OR=1.7), stage (IV OR=1.8) and (partial) gastrectomy for cardia cancers (OR=2.0). CONCLUSION: Variation in POM between hospitals was large but not related to hospital volume. For cardia cancer, POM rates were lower after oesophagogastrectomy.

Binding of Tomato Spotted Wilt Virus to a 94-kDa Thrips Protein.

ABSTRACT Using protein blot assays, a 94-kDa thrips protein was identified that exhibited specific binding to tomato spotted wilt virus (TSWV) particles. Renaturation of the 94-kDa protein, which is conserved among the two major vector species of TSWV, Frankliniella occidentalis and Thrips tabaci, was crucial for its virus-binding properties, whereas under the same conditions no specific binding was observed with aphid (Myzus persicae) proteins. The 94-kDa protein species was present in all developmental stages of both vectoring thrips, whereas it was present mainly in the adult stage of a nonvectoring thrips species, Parthenothrips dracenae. Using antibodies against the different TSWV structural proteins, the G2 envelope glycoprotein was identified as the viral determinant involved. Because the virus-binding protein is present throughout the thrips body, but not in the gut, it may represent a receptor protein involved during circulation of the virus through its vector but probably not during viral uptake in the midgut.

Combination of flucloxacillin and gentamicin inhibits toxic shock syndrome toxin 1 production by Staphylococcus aureus in both logarithmic and stationary phases of growth.

Production of exotoxins by staphylococci and streptococci may lead to the development of toxic shock syndrome (TSS). Because clindamycin inhibits exotoxin production, its use has been advocated for the treatment of TSS. However, the bacteriostatic action of clindamycin might be a disadvantage for the treatment of overwhelming infections. We investigated the effects of flucloxacillin and gentamicin on exotoxin production, because incubation with these antibiotics combines bactericidal action with protein synthesis inhibition. Staphylococcus aureus during the logarithmic and stationary phases of growth was incubated with either clindamycin, flucloxacillin, or a combination of flucloxacillin and gentamicin at concentrations of 2 or 10 times the MIC. In logarithmic-phase cultures clindamycin had a static effect on bacterial growth. After incubation with flucloxacillin, either alone or in combination with gentamicin, a rapid and large reduction in the number of viable bacteria was demonstrated. In stationary-phase cultures none of the antibiotics significantly changed the number of viable bacteria. TSS toxin 1 (TSST-1) production during logarithmic-phase growth was inhibited by > or =95% by all antibiotics. In stationary-phase cultures, clindamycin, flucloxacillin, and the combination of flucloxacillin and gentamicin inhibited TSST-1 production by 95, 30, and 75%, respectively, compared with the level of exotoxin production in the controls. The present results indicate that clindamycin inhibits TSST-1 production and exerts bacteriostatic activity in both bacterial growth phases. Because the combination of flucloxacillin and gentamicin combines the inhibition of exotoxin production with high bactericidal activity at least in logarithmic-phase cultures, it should be considered an alternative to clindamycin for the treatment of exotoxin-mediated diseases, especially in patients with overwhelming infections.

On the relationship between X-bodies and symptom development in plants infected with different tobamoviruses.

The relationship between systemic mosaic symptoms and the occurrence of viral 126-kDa protein in X-bodies was studied in tobacco infected with the tobacco mild green mosaic virus (TMGMV) strains U2, U5, and ribgrass mosaic virus (RMV) strain HR, and in other plant species infected with tobacco mosaic virus (TMV) strain W U 1. Strains U2, U5, and HR coded for proteins of 126, 126, and 130 kDa, respectively, but these were not recognized by antisera against the corresponding protein from W U 1. Only the HR 130-kDa protein reacted with an antiserum raised against a peptide of amino acids 849-863 from the sequence of W U 1. Electron microscopic analysis established the presence of virus clusters in the cytoplasm, as well as in chloroplasts, in leaf tissue infected with U 2 or U 5, and adjacent to nuclei and chloroplasts in scattered cells infected with HR. X-bodies were not detected after infection with any of these strains, but were large and adjacent to nuclei in W U 1-infected tomato displaying severe mosaic symptoms. Large X-bodies were detected near nuclei in W U 1-infected tomato displaying severe mosaic symptoms, but none were detected after infection of tobacco with any of the other tobamoviruses. The induction of X-bodies appears to be characteristic of some tobamovirus only and, at best, can only be associated with, rather than causative of, the severity of symptoms induced by those viruses.

The nucleotide sequence of the M RNA segment of tomato spotted wilt virus, a bunyavirus with two ambisense RNA segments.

The complete sequence of the tomato spotted wilt virus (TSWV) M RNA segment has been determined. The RNA is 4821 nucleotides long and has an ambisense coding strategy similar to that of the S RNA segment. The M RNA segment contains two open reading frames (ORFs), one in the viral sense which encodes a protein with a predicted size of 33.6K, and one in the viral complementary sense which encodes the precursor to the G1 and G2 glycoproteins, with a predicted size of 127.4K. Both ORFs are expressed via the synthesis of subgenomic mRNAs that possibly terminate at a stable hairpin structure, located in the intergenic region. The precursor for the glycoproteins contains a sequence motif (RGD) which is characteristic of cellular attachment domains. Significant sequence homology was found between the G1 glycoproteins of members of the genus Bunyavirus and a corresponding region in the glycoprotein precursor of TSWV, indicating a close evolutionary relationship between these viruses. With the elucidation of the M RNA sequence, the complete nucleotide sequence of TSWV has been determined. TSWV represents the first member of the Bunyaviridae shown to contain two ambisense RNA segments.

Role of Abscisic Acid in the Induction of Desiccation Tolerance in Developing Seeds of Arabidopsis thaliana.

In contrast to wild-type seeds of Arabidopsis thaliana and to seeds deficient in (aba) or insensitive to (abi3) abscisic acid (ABA), maturing seeds of recombinant (aba,abi3) plants fail to desiccate, remain green, and lose viability upon drying. These double-mutant seeds acquire only low levels of the major storage proteins and are deficient in several low mol wt polypeptides, both soluble and bound, and some of which are heat stable. A major heat-stable glycoprotein of more than 100 kilodaltons behaves similarly; during seed development, it shows a decrease in size associated with the abi3 mutation. In seeds of the double mutant from 14 to 20 days after pollination, the low amounts of various maturation-specific proteins disappear and many higher mol wt proteins similar to those occurring during germination are induced, but no visible germination is apparent. It appears that in the aba,abi3 double mutant seed development is not completed and the program for seed germination is initiated prematurely in the absence of substances protective against dehydration. Seeds may be made desiccation tolerant by watering the plants with the ABA analog LAB 173711 or by imbibition of isolated immature seeds, 11 to 15 days after pollination, with ABA and sucrose. Whereas sucrose stimulates germination and may protect dehydration-sensitive structures from desiccation damage, ABA inhibits precocious germination and is required to complete the program for seed maturation and the associated development of desiccation tolerance.

Accumulation of the 126 kDa protein of tobacco mosaic virus during systemic infection analysed by immunocytochemistry and ELISA.

Systemic infection of tobacco with tobacco mosaic virus (TMV) strain WU1, is accompanied by massive accumulation of the virus-coded non-structural 126 kDa protein in X-bodies. The development of X-bodies and the time course of the increase in 126 kDa protein in systemically infected leaves were analyzed by immunocytochemistry and ELISA, respectively, using an antiserum raised against a fusion protein of beta-galactosidase and part of the 126 kDa protein. The ELISA assay developed enabled routine detection of viral 126 kDa (as well as 183 kDa) protein in samples of less than 5 mg of systemically infected leaves. Plants were inoculated by differential temperature treatment, whereafter the accumulation of 126 kDa protein was related to viral multiplication, the development of X-bodies and the formation of symptoms. Both 126 kDa protein and coat protein became detectable between 40 and 66 h after transfer of the plants and increased in parallel up to 200 h. Vein clearing was visible at 66 h, followed by mosaic in the newly developed leaves at 112 h. By electron microscopical analysis small X-bodies, weakly labelled with antibodies against the 126 kDa protein, were detected as early as 24 h after transfer. At this stage they were not associated with nuclei. Thereafter, however, X-bodies increased in size and 126 kDa labelling density, and were increasingly often observed attached to nuclei. In emerging leaves that developed mosaic symptoms, X-bodies were associated with nuclei already at an early stage. These observations are consistent with the hypothesis that association of X-bodies with nuclei may lead to symptom induction, when the leaf is invaded by the virus early in its development.