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Biomedical subjects

P Janssen

Publications and source records attributed to P Janssen.

At least 73 records · Page 4Linked to original sources
PubMed1986

Bacteroides xylanolyticus sp. nov., a xylanolytic bacterium from methane producing cattle manure.

As part of a study of the biogas production from cattle waste, xylanolytic bacteria were isolated from enrichments of fermenting cattle manure. From 34 isolates, mostly Gram-negative rods, a typical strain was investigated in more detail. It was an anaerobic non-sporeforming, Gram-negative rod, which was motile with peritrichous flagella. This organism fermented xylan and many soluble sugars (glucose, cellobiose, mannose, xylose, arabinose). Other hemicelluloses such as gum xanthan, laminaran, locust bean gum, and gum arabic were not utilized. It also could not use cellulose. Fermentation products were carbon dioxide, hydrogen, acetate and ethanol. The bacterium produced carboxymethylcellulase and xylanase, especially when growing on xylan. Growth was optimal between 25 degrees C and 40 degrees C and between pH 6.5 and 7.5. The guanine plus cytosine content of the DNA was 34.8 +/- 0.8%. The isolate was identified as a member of the genus Bacteroides, and a new species is proposed: Bacteroides xylanolyticus (xylan dissolving). The type strain of B. xylanolyticus is strain X5-1 (DSM 3808).

Animals↗
PubMed1986

Onset and termination of accessory facial movements during stuttering.

In this study the onset and offset times of seven types of accessory facial movements during oral and silent prolongations were described in three severe stutterers. For each observed facial movement the onset and offset times were determined by means of slow motion analysis of video-recorded speech samples. For two of the three subjects significant differences in the onset and offset times at the various facial movements were found; however, no consistent patterns in the separate facial movements could be observed. On the contrary, the onset of most facial movements appeared to be located at the very start and their offset at the end of the stuttering moment. The implications of these findings with respect to the function of accessory facial movements in stuttering are discussed.

Adult↗
PubMed1985

Are the accessory facial movements of the stutterer learned behaviours?

The purpose of the present study was to explore the accessory nonverbal behaviours emitted by stutterers when their speech was fluent, normally disfluent, or stuttered. Subjects were 25 stutterers who were required to speak spontaneously for a 2-min. period. Seven types of nonverbal behavior were observed. Significant differences among the three speech categories were obtained for jaw movements, mouth movements, forehead movements, eyebrow movements, and head movements. Eyelid movements and eye blinks were nonsignificant. The results are discussed with respect to the various functions that can be attributed to nonverbal behaviour in stuttering.

Adolescent↗
PubMed1984

Eye movements of stuttering and nonstuttering children during silent reading.

During the silent reading of a 320-word passage, the eye movements of 22 grade school stutterers and 22 nonstutterers were recorded by means of a computer-controlled eye-marker. The recordings were made as a means of determining if the eye movements of the two groups differed and if the differences suggested that the young stutterers showed evidence of word-specific expectancy. Frame-by-frame analysis of the recordings revealed that the stuttering children displayed significantly more eye fixations and eye regressions than the nonstuttering children. The correlations among the different types of eye measures also varied between the subject groups. The differences observed were present despite the fact that the reading level of the two groups was age appropriate and the subjects sampled did not differ significantly in either reading errors or comprehension. These findings are like those previously found when stuttering and nonstuttering adults were similarly tested. They imply that expectancy is not the response province of older stutterers.

Child↗
PubMed1979

An eye-marking investigation of anticipated and observed stuttering.

The subjects of this experiment read a list of words and underlined those on which they expected speech difficulty. The matched and non-stutterers were subsequently called upon to read silently a connected passage in which half of these words were present. During this reading, the relation of eye movement to the words read was recorded on film. Frame by frame analysis of the eyes' exact momentary position revealed that the stutterers evidenced significantly more fixations than did the non-stutterers. They also showed significantly more progressive and regressive eye movements. It follows that the overall duration of their eye movements was somewhat shorter. In contrast, the average duration of the stutterers' fixations were significantly longer for those words on which fluency failure had been anticipated and on words on which it was later observed than on those words on which difficulty was not expected and those on which stuttering did not occur. These data suggest that stutterers search among the words to be spoken and sort out those on which they anticipate and on which they have difficulty.

Adolescent↗
PubMed1977

Receptor affinity and pharmacological potency of a series of narcotic analgesic, anti-diarrheal and neuroleptic drugs.

A series of 26 drugs was tested for in vitro binding to opiate receptors in the presence and absence of 0.1 M NaCl. The results were correlated with assays for in vivo pharmacological potency. Highly significant correlation was found between binding in the presence and absence of sodium ions and analgesic potency. For 10 drugs tested for anti-diarrheal potency significant correlation was observed with binding to brain opiate receptors when binding was carried out in sodium-containing medium. These data add support to the hypothesis that stereospecific opiate binding sites are pharmacological receptors which mediate analgesia and anti-diarrheal action. We found that neuroleptics can bind to opiate receptors with affinities in the micromolar range, in agreement with reports by others. The anti-diarrheal compound loperamide exhibits no significant central opiate effects but binds to opiate receptors from brain in vitro with high affinity. Evidency is presented suggesting that the lack of specific analgesic effect is the result of poor penetration through the blood--brain barrier. Our results lend further support to the similarity of opiate receptors in the brain and in the intestinal tract.

Analgesics, Opioid↗