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Biomedical subjects

R Thompson

Publications and source records attributed to R Thompson.

At least 325 records · Page 18Linked to original sources

Variance function estimation for immunoassays.

A computer program is described which implements a recently described [1], modified likelihood method of determining an appropriate weighting function to use when fitting immunoassay dose-response curves. The relationship between the variance of the response and its mean value is assumed to have an exponential form, and the best fit to this model is determined from the within-set variability of many small sets of repeated measurements. The program estimates the parameter of the exponential function with its estimated standard error, and tets the fit of the experimental data to the proposed model. Output options include a list of the actual and fitted standard deviation of the set of responses, a plot of actual and fitted standard deviation against the mean response, and an ordered list of the 10 sets of data with the largests ratios of actual to fitted standard deviation. The program has been designed for a laboratory user without computing or statistical expertise. The test-of-fit has proved valuable for identifying outlying responses, which may be excluded from further analysis by being set to negative values in the input file.

Analysis of Variance↗

Canine laryngeal oncocytomas.

Solitary, protruding tumors were found in the wall of the larynx in three adult dogs with clinical upper respiratory obstruction. They were composed of cells with abundant granular acidophilic cytoplasm, the granularity caused by an unusually large number of mitochondria. The lesions were considered to be neoplasms arising from oncocytes as described in man. Oncocytomas have not been reported previously in domestic animals.

Adenoma↗

Musculocutaneous neurectomy for spastic elbow flexion in non-functional upper extremities in adults.

The charts of twenty-nine patients who had undergone thirty musculocutaneous neurectomies for acquired spasticity of the elbow in a non-functional upper extremity were reviewed. The most common causes of the spasticity were cerebrovascular accident (59 per cent) and head injury (24 per cent). The aims of the operation were to increase the patient's capacity for self-care and to improve ambulation, personal hygiene, and appearance. Patients who had 30-degree flexion contractures preoperatively did not require a cast postoperatively; those who had 30 to 75-degree flexion contractures preoperatively required a cast postoperatively; and patients who had flexion contractures of more than 75 degrees preoperatively required a concomitant release of soft tissue in the elbow and application of a cast postoperatively. One patient who was operated on to improve appearance had no active elbow flexion postoperatively and was regarded as having a poor result. Musculocutaneous neurectomy is a safe, reliable procedure for treating the spastic elbow in the non-functional upper extremity.

Adult↗

RBC exchange pheresis for priapism in sickle cell disease.

An intermittent-flow blood cell separator was used to perform a sub-total RBC exchange pheresis with prompt relief or priapism secondary to sickle cell disease. The blood cell separator offers an efficient, practical, safe method of performing exchange transfusion in the adult. Surgical procedures in the treatment of priapism have met with limited success and carry a 50% rate of subsequent impotence. We believe that RBC exchange pheresis offers a superior approach in the treatment of complications of sickle cell crisis, including priapism, and should be instituted in the symptomatic patient before more drastic procedures are undertaken.

Adult↗

The control region of the F sex factor DNA transfer cistrons: physical mapping by deletion analysis.

A technique has been developed which allows the isolation of random deletions extending from unique restriction enzyme sites in plasmid DNA molecules. The method involves transformation of E. coli cells with linear plasmid DNAs generated by restriction enzyme cleavage. We have used this technique to map DNA transfer genes in the tra control region of F sex factor DNA. Deletions within EcoRI fragment f6 of F DNA have been isolated and used to assign physical locations to tra genes by a combination of genetic complementation tests, restriction enzyme analysis, DNA heteroduplexing and the analysis of the proteins synthesised in minicells and in vitro. Deletion analysis has also allowed the identification of the traK gene product.

Bacterial Proteins↗

The genome of Bacillus subtilis phage SPP1: the arrangement of restriction endonuclease generated fragments.

SPP1 DNA was cleaved by the restriction endonucleases, BglI, BglII, EcoRI, KpnI, SmaI, and SalI. The molecular weights of the DNA fragments obtained by single enzyme digestion or by consecutive digestion with two enzymes were determined by electron microscopic measurements of contour length and by gel electrophoresis. The major fragments from the six digests could be ordered to give a consistent restriction map of SPP1. The electropherograms of several digests indicated that certain fragments occurred in less than stoichiometric amounts or were heterogeneous in size. Such bands carried a major part of radioactivity, when SPP1 DNA was terminally labelled with P32 prior to degradation by restriction enzymes. These results, and studies of the effect of exonuclease III treatment on restriction enzyme patterns define the terminal restriction fragments. All data obtained support the conclusion drawn in the preceding paper (Morelli et al., 1978 b) that the SPP1 genome is terminally redundant and partially circularly permuted.

Bacillus subtilis↗

Influence of preoperative left ventricular function on results of homograft replacement of the aortic valve for aortic stenosis.

The effect of preoperative left ventricular function on early and late prognosis was assessed in 103 patients with aortic stenosis who underwent left ventricular cineangiography before homograft replacement of the aortic valve. The patients were separated into two groups: Group A (58 patients) with an ejection fraction of 0.46 or more and Group B (45 patients) with an ejection fraction of 0.45 or less. The two groups were compared with respect to clinical and hemodynamic data as well as operative result. There was poor correlation between clinical data and left ventricular function. In Group A there were three early deaths (5.2 percent) and three late deaths (5.2 percent) compared with no early and six late deaths (13.3 percent) in Group B during the follow-up period of 12 to 102 months (mean 43 months). Most patients in Group B showed considerable symptomatic improvement but less than that observed in Group A. Forty-two patients (13 in Group A and 29 in Group B) underwent repeat cardiac catheterization and coronary angiography. Improvement in left ventricular function as assessed by radial analysis of segmental wall motion and ejection fraction was observed in 20 of the 29 patients in Group B. Failure of left ventricular function to improve was associated with additional coronary artery disease in the majority of patients. It is concluded that poor left ventricular function does not increase the risk of aortic valve replacement for aortic stenosis and that improvement in left ventricular function can be expected in the majority of patients.

Adolescent↗

Dissociation of a visual discrimination task into incentive, location and response habits.

Rats previously trained to run from a start box, through a choice chamber, approach and displace a white card rather than a black card and enter a goal box in order to avoid footshock sustained damage to either the medial thalamus, occipital cortex or rostral caudoputamen. The retention test disclosed that the avoidance response was abolished by thalamic lesions, the visual discrimination response was abolished by occipital lesions and the card displacement response was abolished by caudatal lesions. These data demonstrate that this visual discrimination task can be fractionated into a least three discrete habits: One is related to the initiation of the response leading to the reward (incentive habit), the second is related to the location of the correct pathway to the reward (location habit) and the third is related to the response necessary to gain access to the reward (response habit).

Animals↗