Search PubMed⌕ Search

Biomedical subjects

D Rose

Publications and source records attributed to D Rose.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Chronic obstructive bronchopneumopathies. Changes in carbon dioxide pressure during sleep in environmental air and with oxygen].

The effects of oxygen administration were studied in 10 patients with severe obstructive lung disease. Sleep variable and gas exchanges were measured during two nights: one when they were breathing environmental air, the other when they were receiving oxygen. Carbon dioxide saturation and partial pressure measured by the transcutaneous method were continuously recorded. Sleep was perturbed in all patients, but despite wide interindividual variations its amount and quality were improved by oxygen. None of the patients had sleep apnoea syndrome. Oxygen administration was accompanied by a nocturnal increase in carbon dioxide pressure that was about twice as high as that observed under environmental air. Thus, in patients with chronic obstructive lung disease without concomitant infection suppression of the hypoxic stimulus by oxygen therapy seems to result in an increase in carbon dioxide partial pressure identical with the increase produced by sleep alone. Correlations between diurnal and nocturnal oxygen saturation and carbon dioxide partial pressure indicate that patients with the highest degree of hypoxia and hypercapnia in daytime have the most severe nocturnal blood gas disorders.

Blood Gas Monitoring, Transcutaneous↗
PubMed1989

Implications of accurate pathologic margins in the treatment of primary breast cancer.

Eighty-seven patients who underwent mastectomy or reexcision following a previous segmental resection with pathologic margins evaluated at that time were restudied following their definitive therapy. Of these, 40 (46.0%) had involved margins, 28 (32.2%) had close margins, and 19 (21.8%) had clear margins. Residual tumor was subsequently found in 21 (52.5%) of 40, nine (32.1%) of 28, and five (26.3%) of 19, respectively. Analysis of specimens for quadrant of residual tumor showed 27 (31.0%) of 87 patients in the same quadrant, and 11 (14.7%) of 75 present in a different quadrant. The assessment of microscopic margins may be misleading since 29.8% (14/47) of patients with clear or close margins subsequently had residual tumor, and 47.5% (19/40) of those with involved margins had no residual tumor found. Further studies are essential to define the optimum guidelines for tumor excision at the time of segmental resection.

Adult↗
PubMed1989

Statistical analysis of the lactulose/breath hydrogen test in the measurement of orocaecal transit: its variability and predictive value in assessing drug action.

The variability in the orocaecal transit time as measured by the lactulose/breath hydrogen method has been studied for three conditions: lactulose given with a meal, subjects sitting; lactulose given with a meal, subjects semirecumbent; lactulose given in aqueous solution, subjects semirecumbent. Thirty three healthy subjects attended on up to 12 occasions. It was found that administration of the lactulose with a meal significantly reduced the variability (p less than 0.05) and that adoption of the semirecumbent position further reduced variability. A power analysis was used to predict the number of subjects who would be required to show a given percentage change in orocaecal transit time at specified probabilities and powers. A graph and a table for use in the prediction of subject numbers at a probability of 5% and for powers of 50-99% is presented. A dose response curve for metoclopramide using the lactulose/breath hydrogen method is given for doses of 10, 15, and 20 mg.

Breath Tests↗
PubMed1989

The SaO2/t diagram as a useful means to express nocturnal hypoxemia.

The computerization of SaO2 recording during polysomnographic monitoring allows the construction of a diagram expressing the percentage of TIB spent at different steps in saturation. We studied the value of this diagram in three groups of male patients: (1) nine healthy subjects (all volunteers); (2) 25 patients with COPD who had a mean daily SaO2 of 92.3 +/- 1.3 percent; and (3) 25 patients with SAS who had a mean daily SaO2 of 92.1 +/- 1.4 percent. The results show the existence of a discriminating quality in the diagram's morphology, the existence of strong correlations (p less than 0.01) between the percentage of TIB spent at SaO2 less than 85 percent, and the total duration of the desaturation dips.

Aged↗
PubMed1989

Selection of patients for long-term oxygen therapy (LTO).

Serial blood gas measurement must be made for at least three months following an acute exacerbation of chronic obstructive pulmonary disease, to secure stable arterial oxygen tension (PaO2) values. The borderline indications of oxygen therapy concern the patients who have PaO2 over 8 kPa (60 mmHg), but have nocturnal hypoxaemia and/or pulmonary hypertension. The indications of specific drugs such as almitrine are still subject to discussion. The presence of obstructive sleep apnoeas together with ventilatory troubles related to chronic obstructive lung disease (overlap syndrome), is associated with many diagnostic and therapeutic problems.

Blood Gas Analysis↗
PubMed1989

The variability in oro-cecal transit time assessed using a bean-based test meal and its use in the study of the effect of metoclopramide and BRL 24924 on transit time.

The inter and intra subject variation in the oro-cecal transit time assessed using the bean/breath hydrogen method was studied and analyzed to allow estimation of the number of patients/subjects required to show a drug-induced difference for given levels of statistical significance and power. Thus at the conventional 5% level of significance and for a test with 90% power, a dozen subjects should be sufficient to show a drug-induced change which is 25% or greater. Two crossover studies are described using 20 mg metoclopramide and 2 mg BRL 24924, orally, against placebo to investigate their action on oro-cecal transit time. Metoclopramide, 20 mg, produced a 45% reduction in the transit time compared with placebo. BRL 24924, 2 mg, in a similar study showed a 71% reduction.

Adult↗
PubMed1989

Bayesian regression analysis of non-steady-state phenytoin concentrations: evaluation of predictive performance.

Michaelis-Menten saturable pharmacokinetics confound the determination of appropriate phenytoin maintenance doses. This study retrospectively evaluated the performance of an IBM-PC/XT computer program applying Bayesian regression to the "explicit solution to the Michaelis-Menten equation." Zero to five non-steady-state phenytoin serum concentrations were used to predict either non-steady-state concentrations at least 10 days in the future (n = 49) or steady-state concentrations (n = 20). Non-steady-state concentration prediction precision (% mean absolute error) using 0-5 non-steady-state feedbacks was 137%, 62%, 39%, 31%, 25%, and 15%, respectively, and steady-state concentration prediction precision was 446%, 47%, 50%, 44%, 21%, and 13%, respectively. Elimination of subjects receiving concurrent drugs known to induce phenytoin metabolism significantly improved predictions based on population priors; however, performance improvements were not apparent after two serum level feedbacks. The program provided clinically acceptable predictions with four or more feedbacks. Refinement of population parameters and optimal sampling times should further improve performance.

Aged↗
PubMed1989

Treatment of slipped capital femoral epiphysis with a cannulated-screw technique.

Sixty patients (eighty hips) who had slipped capital femoral epiphysis were treated by epiphyseodesis with a cannulated-screw technique. Forty-nine patients (sixty-seven hips) were available for follow-up, forty-four (sixty hips) of whom were followed for a minimum of two years. Thirty-five patients (forty-six hips) were followed until the hardware was removed. Of seventy-two hips in which contrast medium was injected, arthrographic results were obtained in three. In these three hips, there was evidence of pre-existing narrowing of the joint space. Four patients (six hips) who did not have evidence of penetration by a screw or guide-wire had evidence of either pre-existing chondrolysis or osteoarthrosis. Chondrolysis did not develop postoperatively in any patient who had no evidence of it preoperatively.

Adolescent↗
PubMed1988

Morphometrical study of the cat thoracic dorsal root ganglion cells in relation to muscular and cutaneous afferent innervation.

The sizes of neuronal somata in cat dorsal root ganglia were determined at the different thoracic segmental levels (T1-T13). The intersegmental variations in the average value and class distribution of diameters were analysed. The maximal and minimal average mean cell diameters were 51.1 and 43.3 microns at the T1 and T2 levels, respectively. Caudally, this value gradually increased from T2 to T8 (47.8 microns) and thereafter decreased progressively to T12 (44.7 microns). At T1, large cells (greater than 50 microns in diameter) were 3.3-fold in excess compared to small ones (less than 35 microns in diameter). The proportion of large to small cells strongly decreased to a 0.9 ratio from T1 to T2, then increased again from T2 (0.9) to T8 (2.3). The size distributions of the overall cell populations were compared to those of neurones supplying muscular targets via the external intercostal nerves or cutaneous targets via the lateral branch of the internal intercostal nerves, identified following the retrograde transport of horseradish peroxidase. The size distribution of cells serving cutaneous nerves was similar to that exhibited by the overall population of ganglion cells. In contrast, the size distributions of cells giving rise to muscle afferents tended towards smaller values. In the thoracic dorsal root ganglia, the cell body sizes of the muscular primary afferents were close to those previously reported for the visceral primary afferents.

Animals↗
PubMed1988

Mislocalization of diplopic images.

When observers dichoptically view bar stimuli at disparities beyond the fusion limit, the bars are perceived as being closer together than they really are. When 6.0-cycle/deg vertical derivative-of-Gaussian bars are adjusted into apparent alignment with binocularly presented spots, the mislocalization of each bar's half-image is typically 2-5 arcmin for disparities below 60 arcmin. The effect does not generalize to an additional monocular probe bar at more-eccentric locations, thus excluding reflex vergence eye movements as an explanation. Instead, the results indicate a process of interocular matching that seeks to attribute similar directions as well as depths to matching half-images.

Depth Perception↗
PubMed1988

Isolation and identification of mycoplasmas from the nasal cavity of sheep.

Mycoplasmas isolated from the nasal cavity of sheep in a ram test station were examined to determine their identity and prevalence. Specimens were obtained for mycoplasmal culture in 1980, 1982, and 1983 from 558 sheep, and mycoplasmas were isolated from 630 specimens from 320 sheep (57.3%). The isolates were characterized and differentiated into groups on the basis of sensitivity to digitonin, fermentation of glucose, and hydrolysis of arginine. Isolates in some groups were further characterized by use of additional diagnostic media, and their identity was confirmed by agglutination or growth inhibition with antiserum prepared from reference mycoplasmas. Of the 320 sheep with mycoplasmas, 293 had Mycoplasma ovipneumoniae, 12 had M arginini, and 1 had M capricolum. Two sheep had Acholeplasma spp, and 3 sheep had unidentified Mycoplasma spp. The remaining 9 sheep had M ovipneumoniae in combination with Acholeplasma spp (n = 3), M arginini (n = 3), M capricolum (n = 2), and an unidentified Mycoplasma spp (n = 1). The biochemical reactions of the M ovipneumoniae from the 293 sheep were similar, but varied in the degree of growth and fermentation in the basal medium containing glucose. The high prevalence of M ovipneumoniae indicated that it may be commensal in the upper respiratory tract of healthy sheep.

Animals↗
PubMed1988

Disparity range for binocular summation.

Binocular summation of contrast and stereopsis have been linked because they both disappear under certain pathological conditions. The dependence of stereopsis on spatial frequency prompted us to examine how binocular summation varies with both spatial frequency and binocular disparity. We therefore measured binocular summation at different disparities using spatially localized stimuli which were also restricted in their Fourier composition. Contrast thresholds were measured using three interleaved forced-choice staircases for left and right eye monocular stimuli and a binocular stimulus composed of the two monocular stimuli presented simultaneously. At zero disparity binocular thresholds were 1.4 to 1.6 times lower than monocular. As disparity was increased the ratio between the thresholds became smaller, such that at large disparities it was near 1.2, the value expected from probability summation. The range of disparities over which probability summation was exceeded varied with the spatial frequency of the stimulus. At 6.0 cpd the range was 2-3 deg, but at 2.0 cpd or 0.75 cpd the range increased to 4-6 deg. These values closely parallel the range of disparities over which stereoscopic depth sensations occur, but they exceed the limits within which disparate images of an object can be fused into a single percept. The results support the contentions that "neural" summation occurs in the mechanism for stereopsis, that this mechanism uses spatial frequency selective channels, and that this mechanism is separate from the mechanism which mediates fusion.

Adult↗
PubMed1988

In vitro bursting strength studies of laser-welded tissue and comparison with conventional anastomosis.

We compared the mechanical integrity of microvascular anastomoses created with a carbon dioxide (CO2) laser with conventional suture anastomoses. Seventy rat femoral artery segments (35 lased and 35 sutured) were harvested at 1, 24, and 72 hours, and 1, 3, 6, and 12 weeks postoperatively. These segments were subjected to increasingly higher in vitro intraluminal hydrostatic pressures (bursting pressure). Conventionally sutured anastomoses exhibited significantly increased ability (p less than 0.05) to withstand greater bursting pressures than the laser-welded tissue up to 3 weeks postoperatively. After the third postoperative week, the laser anastomoses demonstrated increased bursting pressures compared with the conventional anastomoses. At the end of the 12-week period both groups demonstrated an ability to withstand supraphysiologic pressures in excess of 2000 mm Hg.

Anastomosis, Surgical↗