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Biomedical subjects

M Jordan

Publications and source records attributed to M Jordan.

At least 109 records · Page 6Linked to original sources

Association between growth indicators and volume of lesions in lungs from pigs at slaughter.

Conflicting findings exist among studies on the effect of pneumonia on growth in pigs. We determined the extent of pneumonia in market-weight pigs by use of an objective, volumetric method and linear regression analyses of mean daily gain and days-to-slaughter weight on the percentage of pneumonic lung. In a range of extent of pneumonia between 1.33 and 70.44%, a 10% increase in the volume of pneumonic lung was associated with a decrease in mean daily gain by 41.1 g and a 16.7-day increase in number of days to a slaughter weight of 104.5 kg.

Animals↗

Conservative management of splenic subcapsular hematoma in the third trimester of pregnancy. A case report.

A delayed splenic hemorrhage from a subcapsular hematoma occurred in association with pregnancy. That rare complication carries a high mortality rate, is rarely diagnosed preoperatively and is correctly diagnosed only 20% of the time. The clinical setting and a high index of suspicion led us to investigate for the presence of a splenic hematoma. A computed tomographic scan was invaluable in establishing the diagnosis. We adopted a conservative approach and followed the patient's clinical course from 28 to 40 weeks' gestation, until she delivered vaginally. In general, patient management (conservative vs. splenectomy) and mode of delivery will depend on how close one is to the initial event, on the patient's and fetus's clinical condition and on the gestational age.

Accidents, Traffic↗

[Do ulcerogenic pepsins exist? Characterization of polymorphism of human pepsins].

Studies on the role of pepsin in the pathogenesis of peptic ulcer are hampered by lack of suitable methods for the separation, characterization and quantification of different forms of pepsin. As a contribution toward solving this problem, we have developed several electrophoretic systems which exhibit a high resolving power for pepsins and their precursors, pepsinogens. When human gastric juices were fractionated by discontinuous electrophoresis at pH 3.7 in polyacrylamide gel, pepsin was resolved into as many as 20 distinct forms: 3 major isoenzymes (C, A4, A3), 4 less abundant isoforms (C', A6, A4', A3' or A2), 8-10 minor isoforms of pepsin A1 and at least 3 dimeric isoforms of pepsin A (Ad). All the pepsin components were identified by means of bidimensional electrophoresis. Pepsinogens from gastric mucosa were separated by discontinuous electrophoresis at pH 5.5 in the first dimension, then converted to pepsins in the gel by acidification and resolved by electrophoresis at pH 3.7 in the second dimension. Based on discontinuous electrophoresis at low pH, a much needed method was elaborated for the quantification of different forms of pepsin(ogen) within the stomach. This technique will allow detailed clinical studies which may provide insight into the question whether or not there are specific forms of pepsin that are associated with peptic ulcer.

Electrophoresis, Gel, Two-Dimensional↗

Interneurones of the lumbar cord related to spontaneous locomotor activity in the rabbit. I. Rhythmically active interneurones.

In decorticate, unanaesthetized and curarized rabbit preparations displaying spontaneous fictive locomotor sequences, the firing pattern of neurones was recorded extracellularly in the L6-S1 spinal cord. These neurones, located in the intermediate part of the cord, were not invaded by antidromic stimulation of the hindlimb muscle nerves and thus were considered as interneurones (or propriospinal or tract cells ascending to the brain). When compared to the output from the ipsilateral muscle nerves, these neurones were classified as flexor (F INs) or extensor (E INs) according to the phase of the locomotor cycle when they displayed their maximal firing rate. Among 69 F INs, 33 maintained tonic firing during the periods between episodes of locomotor activity. Their maximal firing rate was in phase with the flexor efferent bursts of the locomotor sequence; during the extensor phase, they maintained an instantaneous frequency (i.f.) that was clearly above the resting i.f. Of these neurones, six became completely silent during the initial flexorextensor coactivation that opened the sequence (F1 neurones) whereas the 27 others increased their firing rate at that time (F2 neurones). The other neurones (36 F3) were silent between the locomotor episodes. Although most of them had a rhythmic activity limited to the flexor bursts, some fired throughout locomotor sequence with a maximal rate during flexor bursts. All the 123 E neurones completely stopped firing during the flexor phase. As was the case for F3 neurone firing, E3 neurone firing (34 neurones) occurred only during periods of locomotor activity. Among the neurones that displayed tonic activity between locomotor episodes, the E2 neurones (24 from 123) remained at this resting value during the extensor phase whereas the E1 neurones (65 neurones) showed an increased i.f. for all or part of this phase. These data, which suggest an asymmetrical genesis of the flexor and extensor activities in locomotion, need to be supported by further analysis.

Animals↗

Specialization in low vision rehabilitation and visual therapy.

A questionnaire was mailed to members of the Low Vision Section (LVS) of the American Optometric Association (AOA) and the Council on Visual Development (COVD) to determine the practice patterns of low vision clinicians, amount and source of specialty training and the extent of dual specialization in both low vision rehabilitation and visual training by members of COVD. Results indicate that 61.1 percent of AOA/LVS members and 20.9 percent of COVD members examine more than four patients per month who require low vision services. Yet, only 2.1 percent of COVD respondents and 32.2 percent of AOA/LVS respondents spend more than 20 percent of their practice time providing low vision services.

Humans↗

Evidence for the entrainment of breathing by locomotor pattern in human.

In human, it has been shown that interactions between locomotor and respiratory patterns may lead to locomotor-respiratory couplings termed entrainment. In order to prove that this coupling is really an entrainment, we tried to show that it obeys one of the expected rules, i.e. that it evolves and is not present for all imposed locomotor frequencies. For that purpose, seventeen healthy volunteers were asked to run on a treadmill at 14 different locomotor rates (instead of 2 or 3 in previous works) for 40 s. All the subjects did not exhibit the same coupling and different relationships could be obtained: the most commonly observed was 2:1 (2 locomotor activities for a respiratory one) but other forms could appear (4:1 and even 5:2 or 3:2). When the coupling evolution was followed in the same subject, it did not appear for all locomotor frequencies but only for locomotor periods close to harmonics of respiratory ones (absolute coordination). On both sides of these values, it progressively evolved to relative coordination and to the lack of coordination. When two forms of absolute coordination were observed in a same subject, the phase relationships followed the rules of the entrainment. Compared to data obtained in quadrupeds, these results suggest that the entrainment of breathing frequency by the locomotor activity is due to central interactions between the respiratory and locomotor pattern generators and does not depend on a chemical regulation avoided here by short locomotor sequences.

Breathing Exercises↗