Randomised trial of compliance with screening for colorectal cancer.

A randomised trial of compliance with screening for colorectal cancer by means of the haemoccult test was conducted in Farnborough and Basingstoke districts. In each of the 14 participating practices (41 general practitioners) 25 852 men and women aged between 40 and 70 years were randomly allocated by household to one of six groups. The group determined the method of invitation to screening: a letter and the test were sent to the patient, or a letter with an appointment to attend the surgery was sent, or during a routine consultation the general practitioner invited patients to participate, and some patients received an educational booklet about bowel disorders and screening. Of the 17 824 people who were offered screening, 7545 (42%) complied. Compliance was significantly affected by the method of invitation, but not by whether an educational booklet was received, and was highest (57%) in the group that was offered the haemoccult test during a routine consultation (the "opportunistic" approach). In this group the compliance rate achieved by individual general practitioners ranged from 26% to 82%. Compliance was significantly higher in Farnborough, in the older (55-70) age group, in women, and in households in which two or more people were offered screening. The higher compliance in Farnborough may be explained by the higher proportion of older people and by the higher proportion of people living in households of two or more in the population that was offered screening. The fact that the screening programme in Farnborough was offered to the whole community and that the researcher may have acted as a facilitator were probably also important. One per cent of the patients screened had a positive test, and 24 (38%) of the 63 patients who were positive and were investigated in hospital had neoplastic disease. The yield was 1.2 cancers and 1.2 benign adenomas (1 cm or larger in size) per 1000 people screened. This low yield is likely to be a consequence of the relatively young age group screened.     

THE LIPID COMPOSITION OF THORACOSPHAERA HEIMII: EVIDENCE FOR INCLUSION IN THE DINOPHYCEAE1

The fatty acid, sterol and chlorophyll composition of the calcified, unicellular alga Thoracosphaera heimii (Lohmann) Kamptner are reported. The presence of 4,23,24-termethyl-5α-cholest-22E-en-3β-ol (dinosterol), 4,23,24-trimethyl-5α-cholest-22E-en-3-one (dinosterone) and the predominance of C₁₈, C₂₀ and C₂₂ unsaturated fatty acids, including the acid 18:5ω3, indicates that T. heimii is a dinoflagellate. The fatty acid: sterol ratio (1.3), is typical of dinoflagellates. The geochemical significance of dinosterone, the high relative concentration of 4-desmethyl-5α-stanols and the role of 23-methyl-5α-cholest-22E-en-3β-ol in the biosynthesis of dinosterol in T. heimii are also discussed.     

Species identity of insect cell lines

Summary Three mosquito cell cultures designated as Suitor's clone ofAedes aegypti, Culiseta inornata andAedes vexans were shown to be moth by immunological, karyological, and isozyme analyses. The cells reacted with rabbit antimoth serum but not rabbit antimosquito serum. Chromosome analyses indicated Lepidopteran rather than Dipteran morphology, and three isozyme systems were confirmative. Any one of these assays would be sufficient to indicate that contamination had occurred and could be used as a periodic check for identity of cell cultures. Morphology and growth characteristics are also valid criteria to distinguish between these particular orders of insect cells. These studies were supported by Grant CA-04953-12 from the National Cancer Institute; General Research Support Grant FR-5582 from the National Institues of Health; and Grant-in-Aid Contract M-43 from the State of New Jersey. Recipient of Research Career Award 5-K3-16,749. from the National Institutes of Health.     

Species identity of insect cell lines

Summary Three mosquito cell cultures designated as Suitor's clone ofAedes aegypti, Culiseta inornata, andAedes vexans were shown to be moth by immunological, karyological, and isozyme analyses. The cells reacted with rabbit antimoth serum but not rabbit antimosquito serum. Chromosome analyses indicated Lepidopteran rather than Dipteran morphology, and three isozyme systems were confirmative. Any one of these assays would be sufficient to indicate that contamination had occurred and could be used as a periodic check for identity of cell cultures. Morphology and growth characteristics are also valid criteria to distinguish between these particular orders of insect cells. These studies were supported by Grant CA-04953-12 from the National Cancer Institute; General Research Support Grant FR-5582 from the National Institutes of Health; and Grant-in-Aid Contract M-43 from the State of New Jersey. Recipient of Research Career Award 5-K3-16,749 from the National Institutes of Health.     

Nitrogen and phosphorus release from decaying water milfoil

To evaluate the net N and P contribution to water from herbicide-killed aquatic weeds, water milfoil containing 1.5% N and 0.30% P was killed with endothal and allowed to decompose, in the dark, in water only or sediment-water systems. Changes with time in dry weight, total N and P, and organic C in the plant material, and organic and inorganic forms of N and P in the water were determined. Plant decompostion was limited by N. Inorganic N was released by the sediment, and decomposition was more rapid when sediment was present. A smaller N requirement for decomposition under conditions of low O₂ was postulated as a possible explanation of the more rapid decomposition observed in the absence of aeration. The presence of plant P in excess of decomposition requirements resulted in rapid accumulation of organic P, followed by inorganic P, in the water. Organic N appeared in the water early in the experiments, but was depleted rapidly, and inorganic N was apparently immobilized as soon as it was formed. In the presence of sediment, organic N and inorganic P levels were much lower. On treating of water milfoil with herbicide, rapid P release can be expected. This P can either be utilized in further biomass production or be sorbed by the sediment. Insufficient data were available to reach definite conclusions regarding N. It would appear, however, that N release from decaying weeds is much slower than P.     

Synthesis of ribonucleic acid in normal bone in vitro

1. The incorporation of [2-(14)C]uridine into nucleic acids of bone cells was studied in rat and pig trabecular-bone fragments surviving in vitro. 2. The rapid uptake of uridine into trichloroacetic acid-soluble material, and its subsequent incorporation into a crude nucleic acid fraction of bone or purified RNA extracted from isolated bone cells, was proportional to uridine concentration in the incubation medium over a range 0.5-20.0mum. 3. During continued exposure to radioactive uridine, bulk RNA became labelled in a curvilinear fashion. Radioactivity rapidly entered nuclear RNA, which approached its maximum specific activity by 2hr. of incubation; cytoplasmic RNA, and particularly microsomal RNA, was more slowly labelled. The kinetics of labelling and rapid decline of the nuclear/microsomal specific activity ratio were consistent with a precursor-product relationship. 4. Bulk RNA preparations were resolved by zonal centrifugation in sucrose density gradients into components with approximate sedimentation coefficients 28s, 18s and 4s. 5. Rapidly labelled RNA, predominantly nuclear in location, demonstrated a polydisperse sedimentation pattern that did not conform to the major types of stable cellular RNA. Material of highest specific activity, sedimenting in the 4-18s region and insoluble in 10% (w/v) sodium chloride, rapidly achieved its maximum activity during continued exposure to radioactive precursor and decayed equally rapidly during ;chase' incubation, exhibiting an average half-life of 4.3hr. 6. Ribosomal 28s and 18s RNA were of lower specific activity, which increased linearly for at least 6hr. in the continued presence of radioactive uridine. There was persistent but variable incorporation into ribosomal RNA during ;chase' incubation despite rapid decline in total radioactivity of the acid-soluble pool containing RNA precursors.     

Triacylglycerol fatty acid and sterol composition of sediment microorganisms from McMurdo Sound,Antarctica

Summary The triacylglycerol fatty acid and sterol profiles of microorganisms from three McMurdo Sound sediment sites, collected during the austral summer of 1984–1985, were determined using gas chromatography and gas chromatography-mass spectrometry. Comparison of the three sites indicated that Cape Evans contained the greatest concentration of triacylglycerol (TG) (220 nmoles/gram dry weight (gdw) of sediment), approximately six to seven times that determined for sediment microorganisms from the Cape Armitage and New Harbor sites. The relative proportion of triacylglycerolderived polyunsaturated fatty acids (PUFA) revealed a somewhat different trend. New Harbor sediment contained the greatest relative proportion of PUFA (22% of triacylglycerol fatty acids), followed by Cape Evans (16%) and Cape Armitage (11%). The proportion of unsaturated fatty acids (poly-and monounsaturated) was relatively constant and ranged from 63% to 71% of the triacylglycerol fatty acids for the three sites. Sterol concentrations varied from 610 pmoles/gdw at Cape Evans, to 370 and 240 pmoles/gdw for Cape Armitage and New Harbor respectively, and was approximately 1% of the total determined lipid. Cholesterol was the major sterol component detected, occurring at similar relative levels (29%) for all three sites. Other sterols present in decreasing order of abundance were 22-dehydrocholesterol, brassicasterol, 24-ethylcholesterol and 24-methylcholesterol. 5-stanols were only minor components of the three sediments, indicating that in situ biohydrogenation of stenols was not a major sterol transformation process in these recent surface oxic sediments.Part 3 in the series: Microbial Ecology in Antarctic Sea-Ice and Benthic Communities