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Biomedical subjects

J R Thompson

Publications and source records attributed to J R Thompson.

At least 217 records · Page 12Linked to original sources
PubMed1987

Capillary gas chromatographic analysis of amino acids in blood and protein hydrolysates as tert.-butyldimethylsilyl derivatives.

A method is given for a one-step derivatization and gas chromatography of amino acids in blood and protein hydrolysates. Blood samples are partially purified by solvent extraction. Protein hydrolysates are neutralized with a triethylamine solution. Then tert.-butyldimethylsilyl derivatives of the amino acids are prepared in a one-step procedure and separated on a 30-m fused-silica SE-30 capillary column. Except for tryptophan and cystine, amino acids are eluted within 30 min. Amino acids are derivatized more rapidly than their corresponding trimethylsilyl derivatives and do not degrade on the long fused-silica columns.

Amino Acids↗
PubMed1987

Magnetic resonance imaging of the normal carotid bifurcation.

A Siemens 0.5 Tesla Magnetic Resonance Imaging (MRI) system was used with the saddle head coil and transverse scout localization for imaging 10 normal cervical carotid artery bifurcations in the sagittal plane. Good to excellent visualization of the flow voids and vessel contours was accomplished in all cases. Careful technique and patient cooperation are required.

Adult↗
PubMed1987

Pericerebellar fluid collections in infancy, sequelae of birth injury? A retrospective CT study.

Retrospective analysis of axial CT scans from 600 consecutive pediatric patients revealed 37 patients (6%) with abnormal low density pericerebellar spaces. Fourteen of these 37 patients (38%) were diagnosed as cerebellar atrophy, whereas 23 of the 37 patients (62%) were diagnosed as mass-like pericerebellar fluid collections. Detailed analysis of the morphology of these spaces suggests that the CT criteria proposed in this paper distinguish between (a) those low attenuation pericerebellar spaces that represent cisternal dilatation caused by cerebellar atrophy (Group I - Atrophy) and (b) those low attenuation pericerebellar spaces that represent low density mass-like collections of fluid which distort a relatively normal cerebellum (Group II - Collections). Analysis of the medical records of the patients in Group II - Collections reveal a high incidence of prematurity, developmental delay, difficult birth and head trauma, possibly indicating that such collections represent sequelae of birth.

Atrophy↗
PubMed1987

Ketone bodies inhibit leucine degradation in chick skeletal muscle.

1. DL-beta-hydroxybutyrate (4 mM) increased the net rate of leucine transamination and the net rate of 2-oxoisocaproate (KIC) production in extensor digitorum communis muscles from fed chicks. 2. DL-beta-hydroxybutyrate at 1 and 4 mM inhibited leucine oxidative decarboxylation in muscles from fed chicks. 3. Acetoacetate at 1 and 4 mM inhibited leucine oxidative decarboxylation and total leucine oxidation, but increased net KIC production in muscles from fed chicks. 4. Both DL-beta-hydroxybutyrate and acetoacetate at 1 and 4 mM inhibited the net rate of leucine transamination and the rates of leucine oxidative decarboxylation and total leucine oxidation in muscles from 24-hr fasted chicks.

Acetoacetates↗
PubMed1987

Computed tomography of condylar and articular disk positions within the temporomandibular joint.

The computed tomograms of temporomandibular joints in 25 patients (41 joints) were retrospectively evaluated for condylar position and joint space with General Electric computer software. Computed tomography scans of the temporomandibular joint were made in the axial plane with the teeth in centric occlusion, and measurements were made from vertically reformatted images. Interarticular joint spaces were measured anterosuperiorly, superiorly, posterosuperiorly, and posteriorly from the condylar surfaces. This was repeated in five equidistant (3.1 mm) serial sagittal planes across the condyle, beginning and ending, on average, 2.5 mm from the lateral and medial condylar poles. Articular disk positions (anterolateral, anterior, anteromedial, medial, and normal) were correlated with condylar position. Significant differences between disk positions and joint spaces were found most frequently in the anterosuperior and the superior joint interval. When the disk was positioned normally, the anterosuperior joint space was consistent (1.5 to 2.0 mm) across the joint (standard deviation, 0.3 to 0.8 mm). The superior, the posterosuperior, and the posterior joint spaces in the normal joint were greater than the anterosuperior joint space. When the disk was anterior to the condyle, the anterosuperior joint interval was widened. When the disk was medial, the superior joint space was significantly wider than normal across the breadth of the condyle. In those joints in which the disk was anteromedial, there was an absence (0.2 mm) of joint space, and this occurred in all areas of the condyle except in its medial one fourth. In the internally deranged joint, joint space narrowing may be focal in nature.

Adolescent↗
PubMed1987

Estimating the infection rate in mothers following caesarean section.

Some hospitals send comparatively few swabs to their laboratories for examination, consequently any measure of infection that depends on routinely analysed swabs is likely to underestimate the actual level of infection. In a survey of routine wound swabs from mothers following caesarean section, it was found that the average infection rate in 31 hospitals was 6%, with considerable variation between the hospitals. Further consideration of the data as described in this paper shows that the actual infection rate was about 14%, with much less variation between hospitals.

Cesarean Section↗
PubMed1987

CT evaluation of trauma to the temporomandibular joint.

The computed tomograms of 43 patients who had suffered craniofacial trauma and who were referred for evaluation of complaints of temporomandibular joint (TMJ) pain and dysfunction were reviewed. Fifteen of the 43 patients (34%) had sustained fractures, 16 (37%) had documented articular disc derangements without associated fractures, and 32 patients (74%) had degenerative joint changes. Computed tomography (CT) showed fractures, degenerative joint changes, and articular disc displacements not seen on conventional radiographs indicating that CT is particularly useful when patients' symptoms are not adequately explained by conventional radiographs or tomograms.

Adult↗
PubMed1987

CT number characteristics of malpositioned TMJ menisci. Diagnosis with CT number highlighting (blinkmode).

The use of computed tomography (CT) number highlighting ("blinkmode") for diagnosing malpositioned temporomandibular joint menisci was investigated. By determining the average CT number, standard deviation, and range for specific periarticular tissues, it is possible to tell how much their attenuation values overlap and, therefore, whether there is a sound basis for distinguishing the disc from adjacent tissues. Fresh and fresh-frozen cadaver specimens, were scanned in axial and direct sagittal planes with 1.5-mm thick overlapping soft-tissue sections. CT number measurements were made for tendon, muscle, fat, and meniscus. Patients also were scanned with overlapping 1.5-mm thick axial soft-tissue sections in order to compare the range of CT numbers in cadavers with that in living subjects. Cadaver joints were cryosectioned at 0.5-mm intervals in the same planes as their CT sections, and the tissue sections were compared with their respective CT highlighted sections. For patients the average CT numbers in Hounsfield units were 88 for tendon, 67 for muscle, -25 for fat, and 100 for meniscus. Fresh unembalmed cadavers showed a higher CT average number for tendon and a lower average CT number for fat. The anatomic sections confirmed the meniscal position seen in the highlighted sections in nine of ten joints (90%) and was equivocal in one. Misshapen and malpositioned discs are seen readily with the blinker function; thinned and normal discs are not. The tendinous insertion of the lateral pterygoid muscle may be confused for meniscus in the medial aspect of the TMJ.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Computed tomography of the normal temporomandibular joint.

A study was made in two parts, retrospective (I) and prospective (II), on two samples of 36 and 17 individuals, respectively, who had temporal bone CT studies for reasons unrelated to TMJ pain and dysfunction. Groups I and II had no radiographic signs of TMJ disease and Group II had neither radiographic nor clinical signs of TMJ disease. Both groups were considered to have normal joints. Joint morphometrics for the two groups (I/II) were as follows; transverse condylar dimensions were 18.5/18.1 mm. Condylar angulation averaged 24 degrees/25 degrees and intercondylar distance averaged 83/83 mm while extra condylar distance averaged 118/118 mm. The condyle in the sagittal plane showed a smooth and rounded form with anterior-superior joint space averaging 1.9/1.7 mm while the central-superior joint space averaged 2.3/2.2 mm. The medial-horizontal joint space averaged 3.9/3.7 mm. The slope of the central portion of the articular eminence averaged 60 degrees/60 degrees in the sagittal plane.

Adult↗
PubMed1987

Structure and expression of the Saccharomyces cerevisiae CRY1 gene: a highly conserved ribosomal protein gene.

The Saccharomyces cerevisiae CRY1 gene encodes ribosomal protein rp59, a component of the 40S ribosomal subunit. Mutations in CRY1 can confer resistance to the alkaloid cryptopleurine, an inhibitor of the elongation step of translation. The nucleotide sequence of the cloned CRY1 gene was determined. The predicted amino acid sequence shows that CRY1 encodes a 14,561-dalton polypeptide that has 88% amino acid sequence homology to the hamster or human S14 ribosomal protein responsible for emetine resistance and 45% homology to Escherichia coli ribosomal protein S11. Analysis of the DNA sequences upstream from CRY1 revealed the presence of three sequences, HOMOL1 (consensus, A/TACATCC/TG/ATA/GCA), RPG (consensus, ACCCA/GTACATT/CT/A), and a thymine-rich sequence, found upstream of more than 20 other cloned yeast genes encoding components of the translational apparatus. We exploited the ability to assay the expression of CRY1 in vivo by using the cryptopleurine resistance phenotype to demonstrate that these three consensus sequences are necessary for the transcription of CRY1. We previously showed that the upstream promoter element of the yeast RP39A gene consists of these identical sequence motifs. Therefore, we suggest that these three sequences define a consensus promoter element for the genes encoding the yeast translational apparatus. CRY1 is one of several hundred yeast genes, including ribosomal protein genes, whose expression is transiently decreased 10-fold upon heat shock. We found that the HOMOL1 and RPG consensus sequences are not necessary for the heat shock response of CRY1.

Amino Acid Sequence↗
PubMed1987

Cerebral vasoconstriction in toxemia.

Three patients with toxemia developed acute neurologic deterioration postpartum. In all, cerebral angiography revealed widespread arterial vasoconstriction. Cerebral vasoconstriction may be an important cause of neurologic complications in toxemia.

Adult↗
PubMed1987

Radiation dose in radiography, CT, and arthrography of the temporomandibular joint.

Thermoluminescent dosimetry studies were performed on a Rando Humanoid head phantom to compare radiation dosages used in temporomandibular joint examinations. Studies included transaxial and direct sagittal high-resolution CT, reduced milliamperage dynamic CT, tomoarthrography, pluridirectional and linear tomography, pantomography, transcranial plain films, and fluoroscopy. Radiation doses were determined for the brain, lens, pituitary gland, condylar marrow, and thyroid gland. Condylar marrow received doses of 64 and 52 mGy, respectively, for the GE 9800 and 8800 high-resolution scans; 21 and 17 mGy, respectively, for the dynamically sequenced scans; and 26 mGy for the GE 9800 direct sagittal sections. Tomoarthrography yielded 31 mGy and fluoroscopy 12 mGy. Other lower doses showed 5 mGy for polytomography, 3 mGy for ipsilateral joint linear tomography, 1.9 mGy for the GE 9800 slow ScoutView, 1.8 mGy for xeroradiography, 0.9 mGy for contralateral joint linear tomography, 0.3-0.4 mGy for transcranial plain films and pantomography, and 0.2 mGy for the GE 8800 ScoutView. The estimated error in this study was calculated to be +/- 15%. On a relative scale, the radiation doses from high-resolution CT and tomoarthrography are high, dynamic CT yields a medium dose, and all other tomographic and plain-film techniques yield low doses.

Arthrography↗
PubMed1987

An early CT sign of ischemic infarction: increased density in a cerebral artery.

The diagnosis of ischemic cerebral infarction by CT usually is not possible for 12-24 hr after the event. A sign that allows earlier diagnosis is increased density of a cerebral vessel secondary to a thrombus or embolus. We report 19 cases of increased density in a middle cerebral artery or one of its major branches visible on the initial CT scan of patients subsequently clinically proven to have suffered a cerebrovascular accident. In three cases angiography confirmed the presence of embolus or thrombus as seen on the CT scans. In several cases subsequent CT scans showed the density to dissipate, thereby confirming its nature as thrombus or embolus. Recognition of this finding will allow earlier diagnosis of ischemic infarction, which may be important in instituting an appropriate therapeutic regimen.

Adult↗
PubMed1987

Rate of passage of corn-canola meal and corn-soybean meal diets through the gastrointestinal tract of broiler and White Leghorn chickens.

The effect of corn-canola meal and corn-soybean meal diets on the form and function of the gastrointestinal tract of broiler (meat-type) and White Leghorn (egg-type) cockerels was measured from 14 to 44 and 14 to 86 days of age or 203 to 1,844 and 115 to 1,777 g of body weight, respectively. Dry weights of the empty crop (P less than .01), gizzard (P less than .001), and ceca (P less than .001) relative to live body weight (g/kg) were lighter in broilers than in Leghorns. Canola meal at 370 g/kg diet was associated with increased (P less than .001) dry weight of the gizzard and jejunum relative to body weight. Soybean meal at 370 g/kg diet was associated with increased (P less than .001) dry weight of the ceca relative to body weight. The lengths, relative to a power of body weight of the duodenum (cm/g.187) and jejunum plus ileum (cm/g.240), were longer (P less than .001) in broilers than in Leghorns. The canola meal diet was associated with an increase (P less than .001) in length of the jejunum plus ileum (cm/g.240) relative to a power of body weight. Mean retention time (MRT) of a particle marker, 103ruthenium phenanthroline, increased with body weight in the entire gastrointestinal tract (P less than .001) and in each of its segments except in the proventriculus, where it was not affected by body weight (P greater than .05), and in the gizzard, where it decreased (P less than .05) with body weight. The MRT, adjusted for body weight in the entire gastrointestinal tract of broilers (338.0 +/- 10.8 min) and Leghorns (359.9 +/- 10.8 min), was similar (P greater than .05) but varied significantly in segments of the gut for both type of chicken and diet. Adjusted MRT was shorter in the crop (P less than .001) and gizzard (P less than .001) and longer in the duodenum (P less than .001) and ileum (P less than .01) of broilers than Leghorns. The soybean meal diet was retained for 2.3 min longer in the duodenum (P less than .001) and 84.2 min longer in the ceca (P less than .001) than the canola meal diet, which accounted for the longer (P less than .001) retention of the soybean meal diet in the entire gastrointestinal tract (388.0 +/- 10.6 vs. 309.8 +/- 10.8 min). Segments of the gastrointestinal tract vary in length, weight, and MRT of digesta with dietary composition and type and body weight of chicken.

Animal Feed↗
PubMed1987

Hepatic serine and alanine metabolism during endotoxin-induced fever in sheep.

Time course changes in plasma amino acid concentrations and the hepatic metabolism of serine and alanine were measured in six mature wethers during endotoxin-induced fever. In separate trials, the animals' responses to injections of saline and endotoxin were measured. The endotoxin was from Escherichia coli serotype 055:B5 and was injected intravenously (4 micrograms/kg body weight). Liver biopsies were obtained from the sheep at 6 h postinjection during both endotoxin and saline injection trials. Rectal temperature in the endotoxin treated animals was increased (P less than 0.05, above that in control animals from 4.25 h to 9 h postinjection, with a maximum rise of 2.43 degrees C at 5.5 h postinjection. Glucose concentration in jugular plasma decreased (P less than 0.05) by 3 h postinjection and remained depressed throughout the 24 h postinjection sampling period. Plasma serine concentration was decreased (P less than 0.05) by 3 h postinjection. Plasma alanine concentration was decreased significantly (P less than 0.05) only at 24 h postinjection. Endotoxin injection increased (P less than 0.05) hepatic oxidation of 14C-serine (162%) and the net incorporation of 14C-serine carbon into hepatic protein (173%) and glycogen (275%). The net incorporation of 14C-alanine carbon into hepatic protein (172%) and glycogen (323%) were increased (P less than 0.05) by endotoxin injection, while alanine oxidation was not affected by endotoxin treatment (P greater than 0.05). The increased hepatic use of serine may explain, in part, the dramatic decrease in plasma concentrations of this amino acid following endotoxin injection into sheep.

Alanine↗
PubMed1987

Lack of concordance of growth rates of primary and recurrent breast cancer.

The degree of concordance of growth rates of primary tumors with corresponding recurrences was investigated by using data from 184 patients with breast cancer with measurable recurrences. For conduction of this examination, the detection processes of both the primary tumor and the recurrence were explored. The probability of detection of a recurrence per unit time was found to be nearly proportional to the tumor's diameter. Approximately 60,000 cells initiated the recurrence, and the distribution of doubling times of the recurrences was exponential, with a mean of 2.1 months. The probability of detection of the primary tumor per unit time was approximately proportional to its volume. The distribution of doubling times of primary tumors was nearly exponential; from other evidence, we inferred that the mean doubling time was also close to 2.1 months. Several techniques to measure growth rate agreement between the primary and recurrent tumors within individuals were developed, and all of them yielded the result that the growth rates are nearly unrelated.

Breast Neoplasms↗