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C Bruce

Publications and source records attributed to C Bruce.

At least 73 records · Page 4Linked to original sources
PubMed1991

A device to aid in the application of stereotactic headframes: technical note.

It is sometimes difficult to apply the headframes of stereotactic systems in awake patients who are lethargic or demented or in patients who are very sensitive to the discomfort of local anesthetic injection. A device for external stabilization of the stereotactic system during its application to the head is described. This device, a modification of the Somi brace, is easy to apply, allows for adjustment of the base ring in all planes and provides sufficient stability even in obtunded or uncooperative patients. This device simplifies and makes more precise the application of the stereotactic headframe and may be of considerable utility in stereotactic surgery.

Equipment Design↗
PubMed1991

[Does the Leveen valve still have a place in the treatment of refractory ascites? An evaluation of 107 cases].

One hundred and seven patients have been treated by the peritoneovenous shunt (PVS) : 54 patients from 1979 to 1984 (P1) and 53 patients from 1985 to 1990 (P2). The mean age was 58 years (25-79 years) and 73 % of the patients had a cirrhosis of alcoholic origin. The mortalities at two weeks and one month were 22 % and 26 % for P1 and 6 % and 11 % for P2. The risk of operation was related to the importance of hepatic and kidney insufficiency and to the importance of hyponatremia. Long term outcome depended on the causal illness. At short term, the morbidity can be reduced and the PVS should be indicated earlier in the progression of the illness.

Adult↗
PubMed1990

Detection of rhinovirus RNA in nasal epithelial cells by in situ hybridization.

This paper describes the development and evaluation of in situ hybridization (ISH) for the detection of rhinovirus in cells obtained from nasal washings of volunteers infected with human rhinovirus 14 (HRV-14). Twenty-five (66%) and 27 (71%) of 38 volunteers inoculated with HRV-14 had evidence of infection by virus isolation and ISH, respectively, on at least one of 4 days investigated after virus challenge. In contrast, only 14 of 38 (37%) volunteers had significant antibody rises as detected by the neutralization test. Of the 38 volunteers inoculated with HRV-14, only 13 (34%) had symptoms of colds. Of these, 12 (92%) and 10 (77%) were positive by virus isolation or ISH, respectively, on at least one day. Six (46%) had significant antibody rises by neutralization. Similarly, of the 38 volunteers challenged, 22 (58%) were asymptomatic and of these 10 (45.5%) and 12 (54.5%) were positive by virus isolation and ISH, respectively, on at least one day. Only 8 (36.4%) of these asymptomatic volunteers showed significant antibody rises by neutralization. There were significant associations between the detection of rhinoviruses by ISH and virus isolation on the third day (P less than 0.025) after virus challenge in the group as a whole and in the symptomatic group. These results show that generally rhinovirus detection by ISH compares well with virus isolation and both tests are clearly more sensitive than the neutralization test in detecting evidence of infection. It is concluded that ISH is an interesting new technique that may play an important role in the study of rhinovirus infection and pathogenesis.

Adult↗
PubMed1990

Diphtheria toxin and its ADP-ribosyltransferase-defective homologue CRM197 possess deoxyribonuclease activity.

The cytotoxic mechanism of diphtheria toxin (DTx) is associated with its ability to inhibit protein synthesis by ADP-ribosylation of elongation factor 2. Although DTx intoxication leads to internucleosomal DNA cleavage and cell lysis, these events do not occur when protein synthesis is inhibited by alternative treatments (e.g., cycloheximide). Here we show that endonucleolytic degradation of DNA is an intrinsic activity of DTx and also of the crossreactive mutant protein CRM197. Assays using DNA-impregnated gels as well as linear and supercoiled DNA in solution revealed not only that CRM197 has nuclease activity but also that its specific activity is actually significantly greater than that of the wild-type molecule. Since CRM197 contains a single amino acid substitution that renders it incapable of ADP-ribosylation, we propose that the active sites for ADP-ribosyltransferase and nuclease activities are distinct.

Binding Sites↗
PubMed1989

Second cytotoxic pathway of diphtheria toxin suggested by nuclease activity.

Diphtheria toxin (DTx) provokes extensive internucleosomal degradation of DNA before cell lysis. The possibility that DNA cleavage stems from direct chromosomal attack by intracellular toxin molecules was tested by in vitro assays for a DTx-associated nuclease activity. DTx incubated with DNA in solution or in a DNA-gel assay showed Ca2+- and Mg2+-stimulated nuclease activity. This activity proved susceptible to inhibition by specific antitoxin and migrated with fragment A of the toxin. Assays in which supercoiled double-stranded DNA was used revealed rapid endonucleolytic attack. Discovery of a DTx-associated nuclease activity lends support to the model that DTx-induced cell lysis is not a simple consequence of protein synthesis inhibition.

Bacteriophage lambda↗
PubMed1989

Detection of enteroviruses using cDNA and synthetic oligonucleotide probes.

This study compares the detection of enterovirus RNA by cDNA probes prepared from both the 5' and 3' end of the genome of coxsackie A21 and B4 with the use of synthetic oligonucleotides prepared from short but highly conserved sequences in the 5' end non-coding region of the picornavirus genome. The cDNA probes detected enteroviruses with a variable level of sensitivity which presumably depended on the degree of genomic homology with the detecting probes. Generally probes from coxsackievirus A21 detected more enteroviruses than did similar probes from coxsackievirus B4. Probes from the 5' end of the genome of both viruses were more sensitive than 3' end probes. In contrast, synthetic oligonucleotides detected all enteroviruses efficiently suggesting that these probes could be useful as 'universal' probes to detect any enterovirus. This paper discusses the application of these probes in the diagnosis and differentiation of enteroviruses.

Base Sequence↗
PubMed1988

Impaired colonic fermentation of carbohydrate after ampicillin.

The aim of this study was to investigate the effect of ampicillin on the ability of the human colon to ferment carbohydrate. The effect of ingesting a drink containing 20 g of lactulose on stool output and breath hydrogen production was measured in 13 normal volunteers before and during administration of ampicillin (2 g/day). Small bowel and whole gut transit times were also measured to exclude any direct effect of ampicillin on motor activity. Ingestion of lactulose did not increase stool weight or frequency under control conditions, but during administration of ampicillin, lactulose caused increases in stool weight (p less than 0.02) and frequency (p less than 0.01), in the percentage of unformed stools (p less than 0.001), and in the excretion of galactose and fructose in stool samples collected from 2 volunteers. Administration of ampicillin also significantly reduced the area under the breath hydrogen profile (p less than 0.03). Mouth-to-cecum transit of the lactulose drink was prolonged during ampicillin ingestion (p less than 0.01) but there was no significant change in the whole gut transit time. These results suggest that ampicillin impairs colonic fermentation of carbohydrate and a diet high in unabsorbable carbohydrate increases the risk of antibiotic-associated diarrhea.

Adult↗
PubMed1988

Why don't Broca's aphasics cue themselves? An investigation of phonemic cueing and tip of the tongue information.

This study investigates whether Broca's aphasics have the information processing abilities necessary to generate and use their own phonemic cues. Twenty patients were studied; ten benefited from phonemic cues given by the therapist. Phonemic cues were most effective with the patients whose naming was most severely impaired. Six patients could indicate the initial letter of words which they could not produce; three of these patients had no knowledge of any relationship between orthography and phonology, so information about the initial letter must be orthographic and not phonological. Only two patients had any success in giving the sounds of written letters. None of the 20 patients had all three abilities needed to use their own cues: giving the first letter of the name, sounding the letter, and utilizing a phonemic cue. The possibility of relearning letter-to-sound correspondences is considered.

Aphasia↗
PubMed1987

Studies on the mechanism of bowel disturbance in ulcerative colitis.

The transit of a radiolabeled meal through the gastrointestinal tract and stool output were measured in 62 patients with ulcerative colitis, subdivided according to the activity and extent of their disease. The results were compared with those from 20 sex-matched normal subjects. Mouth-to-cecum transit was significantly slower than normal in all patient groups although gastric emptying was normal. Whole gut transit was not accelerated in any group of patients. An abdominal x-ray taken 48 h after ingesting the meal showed that patients with active colitis had proximal colonic stasis, whereas transit through the rectosigmoid region was rapid. Stool weights and frequencies were higher in patients with active colitis than in patients with quiescent disease. Patients with active colitis also passed smaller amounts of stool during each bowel movement, suggesting that they experienced a desire to defecate at lower rectal volumes. These results indicate that (a) diarrhea in ulcerative colitis is associated with rectosigmoid irritability rather than rapid transit and (b) caution should be used when treating active colitis with antidiarrheal drugs that could further retard proximal colonic transit.

Colitis, Ulcerative↗
PubMed1987

Duodenal and ileal lipid suppresses postprandial blood glucose and insulin responses in man: possible implications for the dietary management of diabetes mellitus.

Infusion of lipid into the ileum delays the transit of a meal through the stomach and small intestine and could therefore influence the rate and degree of nutrient absorption. Experiments were carried out on human volunteers to investigate the effect of infusion of lipid into either the duodenum or ileum on blood glucose, insulin and gastric emptying after ingestion of a mashed potato meal. Infusions of lipid into either the duodenum or the ileum significantly reduced or abolished the immediate postprandial rises in blood glucose and insulin and significantly delayed gastric emptying. Blood glucose and insulin rose shortly after the lipid infusion terminated. Addition of corn oil to a meal of mashed potato also reduced blood glucose and insulin and delayed gastric emptying. Intestinal lipid can thus modify the glycaemic and insulinaemic responses to a meal, and this modulation probably explains the reduced metabolic responses to a meal containing fat compared with a fat free meal. This principle could be of value in the dietary control of diabetes mellitus.

Adolescent↗
PubMed1987

The prevention of genetically determined orthopaedic defects.

Prevention of genetically determined orthopaedic disorders requires five steps: detection, the establishment of an accurate and specific diagnosis, the establishment of the pattern of inheritance, counseling, and management by early treatment, avoidance of pregnancy, or elective abortion. Elective abortion should only be considered after the diagnosis has been confirmed in utero by one or more diagnostic tests, which include radiography, ultrasound, amniocentesis, fetoscopy, fetal blood sampling, and chorionic villi biopsy sampling.

Bone Diseases, Developmental↗
PubMed1986

Interaction of the Escherichia coli trp aporepressor with its ligand, L-tryptophan.

We have examined the interaction of the Escherichia coli trp aporepressor with its ligand, L-tryptophan, using both equilibrium dialysis and flow dialysis methods. Results obtained by the two procedures were equivalent and indicate that the trp aporepressor binds L-tryptophan with an equilibrium dissociation constant (Kd) of 40 microM at 25 degrees C under standard binding assay conditions (10 mM potassium phosphate, pH 7.4, 0.2 M potassium chloride, 0.1 mM EDTA, 5% glycerol). Molecular sizing of the purified trp aporepressor shows that in the absence of ligand the regulatory protein exists as a dimeric species with greater than 99% purity and an apparent molecular weight of 30,000. Under the storage and assay conditions used, the dimer appears quite stable, and essentially no monomer or higher multimeric species are detected. Analysis of binding data by Scatchard and direct linear plot methods shows two identical and independent ligand-binding sites/native trp aporepressor dimer. When examined as a function of temperature, L-tryptophan binding by trp aporepressor varied over 7-fold (Kd = 28 microM at 6.5 degrees C to Kd = 217 microM at 40 degrees C). At the optimal growth temperature for E. coli (37 degrees C), the dissociation constant was 160 microM for the ligand, L-tryptophan. From the relationship between temperature and L-tryptophan binding by trp aporepressor, the apparent enthalpy change delta H = -10.6 +/- 0.6 kcal mol-1 and the apparent entropy change delta S = -17 +/- 2 cal degree-1 mol-1 were determined.

Chromatography, High Pressure Liquid↗
PubMed1985

Electronystagmogram is useful in the diagnosis of vertebrobasilar and carotid transient ischaemic attacks.

Electronystagmogram examination of patients with transient ischaemic attacks or infarcts in the carotid and vertebrobasilar system revealed significantly increased number of patients with reduced caloric response, abnormal optokinetic nystagmus, saccadic dysmetria and presence of central nystagmus in patients with ischaemia of the posterior circulation. Using the presence of such abnormality as criterion for confirming posterior circulation ischaemia in suspected cases, we have correctly identified 67% of cases of vertebrobasilar infarct, 44% of the transient ischaemic attacks, 83% of carotid infarct and 96% of the carotid transient ischaemic attacks. Electronystagmogram findings of brainstem/cerebrallar system abnormality were found in 36% of transient ischaemic attacks with vertigo, and 50% of infarcts associated with vertigo. Thus Electronystagmogram studies are useful in localising the site of lesion in patients with suspected vertebrobasilar disease or with ischaemic attacks of undetermined territory, and in differentiation of vertigo due to definite cerebrovascular disease from peripheral causes of vertigo.

Aged↗
PubMed1984

Stimulus-selective properties of inferior temporal neurons in the macaque.

Previous studies have reported that some neurons in the inferior temporal (IT) cortex respond selectively to highly specific complex objects. In the present study, we conducted the first systematic survey of the responses of IT neurons to both simple stimuli, such as edges and bars, and highly complex stimuli, such as models of flowers, snakes, hands, and faces. If a neuron responded to any of these stimuli, we attempted to isolate the critical stimulus features underlying the response. We found that many of the responsive neurons responded well to virtually every stimulus tested. The remaining, stimulus-selective cells were often selective along the dimensions of shape, color, or texture of a stimulus, and this selectivity was maintained throughout a large receptive field. Although most IT neurons do not appear to be "detectors" for complex objects, we did find a separate population of cells that responded selectively to faces. The responses of these cells were dependent on the configuration of specific face features, and their selectivity was maintained over changes in stimulus size and position. A particularly high incidence of such cells was found deep in the superior temporal sulcus. These results indicate that there may be specialized mechanisms for the analysis of faces in IT cortex.

Animals↗
PubMed1982

Face recognition by monkeys: absence of an inversion effect.

The effect of inversion of faces upon learning visual discriminations by macaque monkeys was studied with simultaneous discriminations, concurrent discriminations, and transfer tests. In no case was performance with upright stimuli superior to that with inverted stimuli; that is, there was no obvious inversion effect. Studies of human face recognition indicate that the inversion effect is mediated by an orientation-dependent face recognition mechanism that matures within the right hemisphere during childhood. Absence of an inversion effect would indicate that monkeys may not have such a mechanism. It was hypothesized that the macaque's relatively precocious development, smaller cortex, and lack of hemispheric specialization may preclude the maturation of such a mechanism.

Animals↗