Relationship between gangliosides and doubling times in cultured human brain and brain tumor cells

Cells cultured in vitro from normal human white matter and 3 individual brain tumors exhibited the following population doubling times: cells from normal human white matter, 64 ± 22 h, glioblastoma multiforme, 43 ± 11 h; malignant astrocytoma, 98 ± 19 h; and anaplastic oligodendroglioma, 81 ± 24 h. Cells were seeded at subconfluent density, pulse-labelled for 24 h with the ganglioside precursor D-[1-¹⁴C]glucosamine and harvested. Radioactive patterns of extracted gangliosides showed that incorporation of label into disialoganglioside was significantly higher in the samples with longer population doubling times than in samples with shorter population doubling times. These findings suggest gangliosides may play a role in regulation of cell growth.     

Entry age, entry mode and academic performance on a Project 2000 common foundation programme

With the increasing academic expectations in the United Kingdom arising from the demands of the recently-introduced Diploma in Higher Education/ Registration course (Project 2000) and with fairly substantial proportions of both unqualified (DC test) and mature entrants being admitted onto the course, a study was carried out into the relationship between entry age, entry qualifications and academic performance on the common foundation programme, which lasts for the first 18 months of the course The entry data and common foundation programme results of each student from the first three intakes, 258 in total, were reviewed A different subject design was used for the study m which students were placed into one of four groups, according to entry age and entry qualifications, which were (a) 17-21 conventional entry requirements met, (b) 22 + conventional entry requirements met, (c) 17-21 unqualified (DC test entrant), and (d) 22 + unqualified (DC test entrant) Results indicated that the performance of most mature students, whether qualified or not, was above average, with the qualified group securing the best results of any of the four groups Among the 17-21 age group, while the qualified performed as expected, the unqualified performed the worst of any of the four groups, registering both a high discontinuation rate and low overall mean scores for the programme No improvement in the relative performance of the 17-21 unqualified group was noted over the three cohorts and there were indications that under-performance among the unqualified group extended beyond the 17-21 age range In terms of recruitment, results could indicate a need for a change m policy, with evidence of proven academic ability being required from all younger applicants If continued recruitment of unqualified younger students is planned, then a more vigorously targeted policy of academic support and guidance for these students will be required Without this, it seems likely that poor performance and high wastage among this group will continue     

Early and late risk of mitral valve replacement. A 12 year concomitant comparison of the porcine bioprosthetic and prosthetic disc mitral valves

A consecutive series of 706 mitral valve replacements was performed from January, 1972, to January, 1984. The follow-up ranged from 6 to 150 months with a mean of 50 and a median of 43 months. Seven percent (50) of the patient were lost to follow-up. There were 243 men and 463 women, whose ages ranged from 17 to 86 years (mean 58). A porcine bioprosthetic valve was implanted in 528 patients (514 Hancock and 14 Carpentier-Edwards valves) and a prosthetic disc valve in 178 patients (102 standard disc Bj?rk-Shiley, 34 Beall, and 42 Harken disc valves). Seven patients were in Functional Class II, 325 in Class III, and 374 in Class IV. A concomitant operative procedure was performed in 253 of the 706 patients (36%). Mitral regurgitation was the primary hemodynamic lesion in 363 and mitral stenosis in 343. Operative mortality figures were as follows: 77 of 706 (11%) for the overall group, 34 of 453 (7.5%) for isolated mitral valve replacement, 30 of 169 (17.5%, p = 0.001) for mitral replacement plus coronary bypass, 49 of 528 (9%) for the bioprosthetic valve group, and 28 of 178 (16%) for the prosthetic disc valve group (p = 0.01). After the operation, 262 patients were in Functional Class I, 99 in Class II, and 18 in Class III. The long-term survival rate was significantly lower in patients who had an associated procedure (45% +/- 6%), who had mitral regurgitation rather than mitral stenosis (53% +/- 5% versus 67% +/- 4%) (p = 0.002), who were in Functional Class IV rather than Classes I to III (51% +/- 4% versus 70% +/- 4%) (p = 0.001), and who received a prosthetic disc valve rather than a bioprosthesis (40% +/- 6% versus 67% +/- 4%) (p = 0.001). Thromboembolic rates were significantly higher with prosthetic valves than with bioprosthetic valves (4.6% +/- 0.22% versus 2.4% +/- 0.5% per patient-year of follow-up), and the incidence of anticoagulant-related hemorrhage was significantly higher in the prosthetic valve group (1.65% versus 0.43% per patient-year). Primary valve dysfunction was significantly more common in the bioprostheses (1.23% versus 0.40% per patient-year).(ABSTRACT TRUNCATED AT 400 WORDS)     

Putative adhesins of Anaplasma marginale: major surface polypeptides 1a and 1b.

Genes for the MSP1a and MSP1b subunits of the Anaplasma marginale surface antigen complex MSP1 were previously cloned and expressed in Escherichia coli. We report here the localization of MSP1a and MSP1b polypeptides on the surface of recombinant E. coli by using a live cell indirect immunofluorescent antibody assay. Recombinant E. coli cells expressing the msp1 alpha gene or the msp1 beta gene encoding the MSP1a and MSP1b polypeptide subunits, respectively, were shown by a culture recovery adhesion assay and by direct microscopic examination to specifically adhere to bovine erythrocytes. This adhesion was more than additive when both genes were coexpressed in a single recombinant construct. Similarly, these recombinants hemagglutinated bovine erythrocytes in a microtiter hemagglutination assay. Inhibition of recombinant E. coli adhesion to bovine erythrocytes and hemagglutination inhibition were observed in the presence of homologous monospecific polyclonal antiserum raised against purified MSP1a or MSP1b polypeptide. These data suggest that the MSP1a and MSP1b polypeptides have functions as adhesins on A. marginale initial bodies, probably during erythrocyte invasion.     

Treatment decisions in axillary node-negative breast cancer patients.

Treatment decisions must be made on 9000 axillary node-negative breast cancer patients each month in the United States. Which of these patients will benefit from adjuvant therapy is a major question. Valid methods are needed to distinguish those patients who are "cured" from those who will suffer a cancer recurrence. A complex network of prognostic variables enters into the treatment decision, together with a risk-versus-benefit assessment. We are using a neural-network-based form of artificial intelligence that, once "trained" with data representing an event and its outcome, can identify subsets of patients with low recurrence risks. Larger data sets are being evaluated with the hope of introducing the neural-network technique to routine clinical practice.