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R Thompson

Publications and source records attributed to R Thompson.

At least 163 records · Page 9Linked to original sources
PubMed1992

Variance decomposition in the estimation of genetic variance with selected data.

Estimation of genetic variance in populations under selection involves assumptions on base animals. Base animals are often considered unselected and it also has been proposed to treat selected base animals as fixed. The consequences of assumptions on base animals in the estimation of genetic variance in selected populations are not fully understood. Variance decompositions are introduced for simple designs to quantify the differences between models that treat base animals in different ways. Independent contrasts were constructed and REML estimates of variance components were compared for different designs and selection rules. The method shows how selection is accounted for in a complete model and why estimation of variance components can become biased when base animals are treated as fixed.

Animals↗
PubMed1992

Secretory leucocyte proteinase inhibitor: inhibition of fibronectin degradation by neutrophil elastase.

Degradation of surface-bound fibronectin of the upper respiratory tract by human leucocyte elastase (HLE) was shown to favour colonization of these mucosal surfaces by Gram-negative bacteria. We investigated the degradation of fibronectin by purified HLE and by enzymes released from stimulated human polymorphonuclear leucocytes (PMNs), in the presence of recombinant secretory leucocyte proteinase inhibitor (rSLPI) and alpha 1-proteinase inhibitor (alpha 1-PI), the two main inhibitors of HLE within the airways. Our results show that HLE degraded fibronectin at concentrations as low as 0.2 nM. To inhibit the degradation of fibronectin by pure HLE in an experimental system in which the enzyme was premixed with inhibitor, a twofold molar excess of rSLPI and an equimolar concentration of alpha 1-PI were required. On the other hand, a fivefold molar excess of rSLPI was necessary to inhibit degradation of fibronectin by enzymes released from stimulated neutrophils. In order to estimate the role of oxidants generated by stimulated PMNs in the activation of the inhibitory capacity of rSLPI by stimulated PMNs, we preincubated PMNs with antioxidants such as superoxide dismutase, methionine, catalase or Na-azide prior to stimulation of the cells. Under these conditions, a threefold molar excess of rSLPI over released HLE was required to inhibit the degradation of fibronectin, raising the possibility that either exogenous or endogenous antioxidants in the lung could be important in improving the efficacy of this therapeutic antiprotease. We conclude that a molar excess of rSLPI to HLE is always necessary to inhibit fibronectin degradation by HLE, and that addition of antioxidants partly prevents the inactivation of rSLPI by oxidants released from stimulated PMNs.

Antioxidants↗
PubMed1992

Managing resources in the operating department.

A number of articles on the problems of resource management have been published in these pages over the past few years. Although these articles highlighted some of the difficulties and problems faced by theatre nurses, none actually gave a means of resolving them.

Cost-Benefit Analysis↗
PubMed1992

Hemicorporectomy for acute aortic occlusion: a case study.

Hemicorporectomy has been done for potentially curable pelvic malignancy and for intractable pelvic sepsis with bone involvement. In this report, the authors describe the first use of hemicorporectomy to treat ischemic gangrene of the limbs and pelvic soft tissues secondary to acute aortic occlusion.

Acute Disease↗
PubMed1991

First steps in audit.

The results of two audit projects carried out in a District Orthodontic Unit are described. Although prospective data collection was the goal, it was found that this method yielded little information as the data collection forms were poorly filled in. The main problem was a lack of definition of terms and inadequate discussion between clinical and clerical staff. A retrospective audit using five clearly defined fields was more successful. It is very important that there is provision to verify the data collected. The time commitment for clinical staff should not be underestimated.

Data Collection↗
PubMed1991

Lung asbestos fiber content and mesothelioma cell type, site, and survival.

All ascertainable cases of malignant mesothelioma in Australia were notified to a national surveillance program in the period January 1, 1980 to December 31, 1985. There were 854 cases obtained and 823 confirmed on clinical (77) or histologic (746) ground. Tumor site was known in 759 cases (685 pleural and 74 peritoneal). Lung fiber content analyses by light microscopy and analytic transmission electron microscopy with energy-dispersive x-ray analysis were done on 226 cases in which postmortem material was available, using the method of Rogers. Cell type was determined by a five-member expert panel of pathologists appointed by the Royal College of Pathologists of Australasia. There was a statistically significant trend between lung fiber content (fibers/g dry lung) and cell type from epithelial (low fiber content) through mixed to sarcomatous (high fiber content). This trend was most apparent for total uncoated fibers (chi-square = 6.8, df = 1, P less than 0.01) and crocidolite (chi-square = 6.7, df = 1, P less than 0.01). Lung fiber content also was associated with tumor site; higher lung fiber content being associated with peritoneal tumors. This relationship was significant for all fiber content measures except chrysotile and was independent of the fiber content-cell type relationship (log-linear analysis). Survival from time of provisional diagnosis was significantly longer for epithelial (mean, 13 months; standard deviation [SD], 12.8) and mixed (mean, 10.2 months; SD, 8.7) types than sarcomatous cell types (mean, 5.8 months; SD, 6.5; P less than 0.0001, by analysis of variance on log10 survival time). Survival time was significantly greater for pleural tumors (mean, 11.4 months; SD, 13.4) than peritoneal tumors (mean, 8.6 months; SD, 12.5) (P less than 0.005, by Student's t test on log10 survival time).

Asbestos↗
PubMed1991

The incidence of malignant mesothelioma in Australia 1982-1988.

From 1980 to 1985, the Australian Mesothelioma Surveillance Program, and since 1986, the Australian Mesothelioma Register, have been collecting data on all cases of malignant mesothelioma that could be ascertained in Australia. Incidence rates were calculated on 854 Program and 696 Register cases (total 1271) diagnosed in Australia between January 1, 1982 and December 31, 1988. Australia has one of the highest national rates of mesothelioma in the world (15.8 cases per million of population aged 20 years and older), and the rate is rising. The rate is far higher in males (28.3) than females (3.3). The Western Australian rate (28.9) is the highest among the states, as may be expected because of the crocidolite mine at Wittenoom; however, the largest numbers of cases occur in the more populous and industrial New South Wales. The high incidence rate, its expected continuing increase, and absence of a history of exposure to asbestos in approximately 28% of cases, demand consideration of potential environmental factors other than asbestos in the causation of this tumor, as well as continued surveillance.

Adult↗
PubMed1991

Evolution of herpesvirus thymidine kinases from cellular deoxycytidine kinase.

The thymidine kinases encoded by herpesviruses of higher vertebrates form a distinct group and are unrelated to the thymidine kinases (TKs) of other organisms. Their evolutionary source has not been identified, but our analysis has revealed a clear relationship with a sequence of human deoxycytidine kinase (dCK) published recently. We report the sequence of the putative TK of channel catfish virus, a herpesvirus of a lower vertebrate, and show that it is also related to dCK. We propose, therefore, that the TKs of herpesviruses of higher and lower vertebrates have evolved, either independently or successively, from a cellular dCK.

Amino Acid Sequence↗
PubMed1991

Three high-lysine mutations control the level of ATP-binding HSP70-like proteins in the maize endosperm.

The synthesis and deposition of seed storage proteins in maize are affected by several dominant and recessive mutants. The effect of three independent mutations, floury-2 (fl2), Defective endosperm-B30 (De-B30), and Mucronate (Mc), that reduce zein level in the endosperm were investigated. These mutations also control the level of b-70, a polypeptide bound to protein bodies, which is separable into the two isoforms b-70I and b-70II by two-dimensional gel electrophoresis. Both isoforms are overexpressed 10-fold in fl2; however, only b-70I is present in De-B30 and Mc, which contain an amount of total b-70 isoforms fivefold higher than in the wild type. Both b-70I and b-70II resemble heat shock protein (HSP70) in that they bind ATP, cross-react with anti-HSP antibodies, and have N-terminal sequence homology to HSP70. All maize protein body-located b-70 characteristics are typical of those of chaperone-like HSPs. A third protein, b-70III, similar in size to but slightly more acidic than b-70I and b-70II, also binds ATP and reacts with the same antibody, providing evidence for the presence in endosperm extracts of a cytosolic chaperone-like protein. The level of b-70III was not altered by the mutations studied. The results suggested that the repression effect of the three mutations on zein accumulation may be mediated by the alteration of a zein transport or zein assembly process involving b-70I and b-70II.

Adenosine Triphosphate↗
PubMed1990

How district health authorities organise cervical screening.

OBJECTIVES: To examine how district health authorities organised cervical screening with respect to Department of Health guidelines and to determine their assessment of the problems encountered. DESIGN: Postal questionnaire sent to all 190 district health authorities in England in 1989. PARTICIPANTS: 190 District health authorities in England. MAIN OUTCOME MEASURES: Population coverage of screening, quality of smear testing, and follow up of abdominal test results in comparison with national guidelines for district cervical screening services, and problems encountered by districts. RESULTS: Replies were received from 178 (94%) of districts, in 143 of which the person named as responsible for cervical screening contributed. All districts implemented a computer managed scheme, 150 by the target date of 31 March 1988, but not all of these conformed with the guidelines. At the time of the survey only just over half called women in the target age group of 20-64 and only 70% expected to meet the target date of 13 March 1993 for completing the call. Considerable variation was evident among the schemes with regard to how they dealt with issues related to population coverage, quality of testing, and follow up of abnormal results. The problems most commonly identified by the districts (n = 174) were laboratory workload (107, 61%), computer software (104, 60%), availability of resources (78, 45%), non-attendance (77, 44%), rate of opportunistic screening (62, 36%), and investigation and treatment (60, 34%). CONCLUSIONS: Current practice in running cervical screening schemes needs to be examined to determine the extent to which it contributes to the goal of reducing mortality from cervical cancer.

Adult↗
PubMed1990

Anatomy of the rat medial geniculate body: II. Dendritic morphology.

The medial geniculate body (MGB) of the rat was studied with Golgi methods to determine the distribution of neurons identified by dendritic morphology. These findings were compared with major divisions and constituent nuclei established by somatic and fiber architectonics, and by connections with temporal neocortex (Clerici et al.: Society of Neuroscience Abstracts 12:1272, 1986; 13:325, 1987; Anatomical Record 218:23, 1987; Winer and Larue: Journal of Comparative Neurology 257:282-315, 1987; Clerici and Coleman: Journal of Comparative Neurology 297:14-31, 1990). It was found that an elaboration of the prototypical scheme proposed by Morest (Journal of Anatomy 98:611-630, 1964) for partitioning the mammalian MGB is valid for characterizing the rat MGB. Two predominant categories of principal neuron dendritic patterning were identified: a bushy cell having tufted dendritic fields and a stellate cell with a radiate dendritic domain. Tufted neurons have large caliber dendritic trunks that divide profusely into daughter branches close to the soma with intertwining higher order branches that maintain a relatively restricted dendritic field. Stellate neurons typically emit primary dendrites in all directions that then divide dichotomously at wide angles at subsequent orders of branching to produce a somewhat spheroidal dendritic field. In the present study, the rat MGB is found to be a tripartite structure composed of ventral (MGv), dorsal (MGd), and medial (MGm) divisions, each uniquely characterized by constituent dendritic morphology. The paramount neuronal class of the MGv is the tufted principal cell. In the ventral and ovoid nuclei of the MGv the neuronal orientation of highly oriented bitufted cells is in register with afferent brachial axons. In the ventral nucleus, this arrangement approximates vertical with a dorsomedial tilt most prominent rostrally; in the ovoid nucleus, tufted cells adhere to the double spiraled course of afferent axons. The transition zone between ventral and ovoid nuclei contains tufted neurons that align with radially oriented fibers issuing from the junction of the ovoid and midgeniculate bundles. Bitufted neurons of the marginal zone parallel fibers at the lateral margin of the geniculate. Within the MGd the dorsal and caudodorsal nuclei are characterized by stellate cells with extensive dendritic arbors and busy neurons with dendritic branches less tufted than those observed in the MGv. The deep dorsal nucleus contains bitufted neurons that polarize with the long axis of the midgeniculate bundle and intermingle with stellate neurons. The suprageniculate nucleus includes neurons with large somata and long, sparsely branched and dorsoventrally oriented dendrites orthagonal to corticothalamic axons, as well as smaller neurons and classical stellate cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

The b-32 protein from maize endosperm: characterization of genomic sequences encoding two alternative central domains.

As derived from a cDNA clone, the structure of the b-32 protein of Zea mays, a putative regulatory factor of zein expression, has a central acidic region separated by two domains covered by secondary structure motifs. In this work, three b-32 genomic clones were selected from two genomic libraries obtained from the maize inbred lines W64A and A69Y. The nucleotide sequences of the complete coding region of each b-32 gene, as well as long stretches of their 5' and 3' flanking regions, were determined. Introns are not present in the b-32 genomic sequences. Minor variations among the three genes and an earlier reported b-32 cDNA indicates that they constitute a gene family showing a characteristic polymorphism. Such a polymorphism is highly evident in large segments of the upstream regulatory sequences. Interestingly, when compared with cDNA (W64A) or with gene b-32.120 (W64A), the genes b-32.129 (W64A) and b-32.152 (A69Y) show three jumps of the reading frame in the central part of the coding region, resulting in a completely different sequence of the b-32 protein central domain. In all cases, variations in the N- and C-terminal domains account only for microheterogeneity.

Amino Acid Sequence↗