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J Van Hees

Publications and source records attributed to J Van Hees.

At least 19 recordsLinked to original sources
PubMed2002

Oral mucosal versus cutaneous sensory testing: a review of the literature.

The innervation of skin and oral mucosa plays a major physiological role in exteroception. It also has a clinical interest as illustrated by sensory changes after neurosurgical procedures. These sensory changes often rely only on the patients' subjective reports, although objective assessments are possible. This review compares the neurophysiological features of the trigeminal sensory pathways with those of cutaneous sensory innervation. In this review, three receptor groups will be discussed: mechanoreceptors, thermoreceptors and nociceptors. Differences between receptors in the glabrous skin, the hairy skin and the oral mucosa will be highlighted. Sensory testing devices have been developed to quantify psychophysiological parameters such as the threshold level for receptor activation upon mechanical stimulation, but such devices have been merely developed to determine the threshold of skin receptors (tactile, thermal). Later on, some have been adapted to suit the particularities of the oral environment. This review attempts to compare the available literature on test devices for oral versus cutaneous tactile function. It summarizes what is common or rather particular to the devices used to study either cutaneous or oral receptors.

Adolescent↗
PubMed2002

Small intestinal morphology and disaccharidase activities in early-weaned piglets fed a diet containing spray-dried porcine plasma.

The purpose of this study was to test whether dietary spray-dried porcine plasma (SDPP) in early-weaned piglets prevents small intestinal villus atrophy by trophic or protective activity. Fifty-four weaned, 18-day-old piglets were used to determine the effect of dietary SDPP on small intestinal villus length, crypt depth, enterocyt mitotic activity and brush border enzyme activities during the first week after weaning. The piglets were offered a diet containing either 8% SDPP or 8% casein. At 2 and 7 days after weaning, piglets were anaesthetized to provide samples of the small intestinal wall and killed immediately afterwards. There were no differences in daily gain and daily feed intake between the two dietary treatments. At day 2 after weaning, all piglets showed a marked reduction in villus height when compared with baseline values. In all piglets, small intestinal enterocyte mitotic activity had decreased by day 2 and was increased again on day 7. There were no significant effects of dietary SDPP on small intestinal villus length, crypt depth and enterocyt mitotic activity. This indicates that SDPP has no trophic effect on the small intestinal mucosa and that it does not protect against the damaging effect on the small intestinal villi that is associated with the process of weaning. There was no effect of SDPP on lactase-, sucrase- or maltase-specific activities that are a measure of the digestive function of the small intestine. It can be concluded that SDPP versus casein has no effect on small intestinal morphology and disaccharidase activities in early weaned piglets kept under low infection pressure.

Animal Feed↗
PubMed2001

Trigeminal somatosensory evoked potentials in humans.

The recording of somatosensory evoked potentials (SEPs) is a non-invasive routine clinical testing procedure in neurology. For trigeminal nerve stimulation, however, SEPs have not received a widespread clinical attention. A variety of protocols and procedures have been used to record trigeminal SEPs (TSEPs). Differences encountered include the stimulation mode, site and frequency, the recording electrode position and data acquisition parameters. This has resulted in a diversity of recorded TSEP signals, making comparisons almost impossible. The general picture shows a number of short latency waves (within 3 ms) of peripheral origin, followed by at least two longer latency waves (12-15 ms and 19-22 ms). Furthermore, potential waves with a very long latency (> 100 ms) follow when the response is produced by painful stimulation. The origin of the long and very long latency waves is still a matter of debate. In order to allow reliable data interpretation and comparisons between the outcome of different studies, a standardized protocol should be applied for TSEP recordings. By providing an overview, this paper aims to mark a step forward in the harmonization of TSEP protocols with respect to the neural processes of interest. Further studies should also encounter the potential application of other neuroimaging techniques, such as functional magnetic resonance imaging or positron emission tomography, preferably in combination with TSEP recordings.

Adolescent↗
PubMed2000

Sensations and trigeminal somatosensory-evoked potentials elicited by electrical stimulation of endosseous oral implants in humans.

The perception of bipolar electrical stimuli through implants was studied. The stimuli were delivered to permucosal oral endosseous implants in 15 individuals, who then reported tapping to beating sensations. In 10 out of the 15, these stimuli evoked clearly distinguishable potentials in the averaged electroencephalograms. The most prominent scalp potential was a positive wave with a latency between 18 and 25 ms, often preceded by a negative wave with a latency around 12-17 ms. In contrast, when a motor response was elicited by stimulation of the lip, a shorter latency wave around 8-11 ms was found additionally, indicating that the former-mentioned waves represent a true sensory response and not an artefact of myogenous origin. Furthermore, topical anaesthesia of the gingiva surrounding the implants in six individuals had little effect on the sensory responses. This evidence excluded peri-implant mucosal innervation as the origin of the perception and of the somatosensory-evoked waves elicited by the electrical stimulation of the oral implants. To the best of our knowledge, for the first time a sensation (osseoperception) has been elicited by electrical stimulation of endosseous oral implants and correlated with simultaneously recorded trigeminal somatosensory-evoked potentials (TSEPs).

Adult↗
PubMed2000

Value of somatosensory and motor evoked potentials in predicting arm recovery after a stroke.

OBJECTIVES: Prediction of motor recovery in the arm in patients with stroke is generally based on clinical examination. However, neurophysiological measures may also have a predictive value. The aims of this study were to assess the role of somatosensory (SSEPs) and motor (MEPs) evoked potentials in the prediction of arm motor recovery and to determine whether these measures added further predictive information to that gained from clinical examination. METHODS: Sixty four patients who had had a stroke and presented with obvious motor deficit of the arm were examined in terms of three clinical variables (motor performance, muscle tone, and overall disability) and for SSEPs and MEPs. Clinical and neurophysiological examinations were done at entry to the study (2 to 5 weeks poststroke), and at about 2 months after stroke. Further clinical follow up was conducted at 6 and 12 months after stroke. RESULTS: Neurophysiological measures made in the acute phase were of little use alone in predicting motor recovery of the arm at 2, 6, and 12 months after stroke. At 2 months, the absence of SSEPs and MEPs indicated a very poor outcome. Conversely, if the responses were preserved, a great variation in motor outcome was found. Multiple regression analysis showed that the addition of SSEPs and MEPs to the clinical examination increased the possibility of predicting arm recovery in the long term. In the acute phase, the combination of the motor score and SSEPs were best able to predict outcome. The long term outcome based on variables taken at 2 months, was best predicted through incorporating the three clinical measures and MEPs. CONCLUSIONS: Neurophysiological measures alone are of limited value in predicting long term outcome. However, predictive accuracy is substantially improved through the combined use of both of these measures and clinical variables.

Analysis of Variance↗
PubMed1997

Effect of the life-span of female Glossina palpalis gambiensis on the weight and size of its progeny.

Pupae and teneral flies of Glossina palpalis gambiensis originating from three successive reproductive cycles were compared for their size and weight. In general, pupal weight and fly weight increased, whereas fly size, measured as wing vein length, decreased with the number of reproductive cycles. The linear regression observed between weight and wing vein length of the fly demonstrated that, particularly for flies originating from the first and second larvipositions, small changes in wing vein length reflected substantial differences in weight. The results of these laboratory experiments were compared with some field data on Glossina morsitans from Zambia and related literature. The life span of the female tsetse, affecting the size of her progeny, could clarify partially some of the field observed seasonal changes in size, whereas the correlation between fly size and weight could eventually explain the differential mortality of some size classes of tsetse flies. However, whether these laboratory observations can be extrapolated to the field has still to be confirmed.

Animals↗
PubMed1996

Peripheral cutaneous nerve distribution to the fingers.

Both sensory distribution charts and the unaffected side, are used as reference points in the assessment of cutaneous innervation. Sensory nerve conduction studies, in particular, often use comparison between sides. However, remarkable differences can be found between various sensory innervation maps, and no evidence was found in the literature for the assumption that the pattern of cutaneous sensory distribution of the peripheral nerves between the left and right limbs is symmetrical. The purpose of this study was to investigate variations in the sensory innervation of the fingers by means of a neurophysiological method, and to compare the results for the left and right hands. The subjects of this study were 31 young women. Percutaneous peripheral nerve stimulation was performed on the four nerve branches providing sensory innervation to the fingers, and action potentials were sought from the fingers by use of annular surface electrodes. Variations in the cutaneous innervation of the fingers between individuals often occurred and were found more frequently on the dorsal than the palmar aspect. The distribution of sensory innervation may even differ markedly between hands in the same individual. The cutaneous innervation of all peripheral nerves supplying the fingers may differ from the innervation patterns described in the various distribution charts. Prudence is called for when applying sensory distribution charts as absolute references for the assessment of cutaneous sensation in patients. Caution should also be applied when comparing one hand with the other when assessing the cutaneous innervation of the fingers.

Action Potentials↗
PubMed1996

Pathological findings in a patient with amyotrophic lateral sclerosis and multifocal motor neuropathy with conduction block.

We studied a 53-year-old woman with progressive weakness of the left arm, gradually spreading to the other limbs. Neurological examination revealed a motor neuron syndrome with paresis, fasciculations and atrophy. Electrophysiological studies showed multiple motor conduction blocks. The anti-GM1 IgM titer was elevated. The patient was thought to have a multifocal motor neuropathy. Despite intravenous cyclophosphamide treatment, however, she died with respiratory insufficiency. On postmortem examination, the brachial plexus showed patches of demyelination underlying different areas of motor conduction block. The spinal cord, however, revealed severe neuronal loss in the ventral horn and axonal loss in the corticospinal tract, indicative of amyotrophic lateral sclerosis. Demyelination of peripheral nerves could have been responsible for the other conduction blocks in this patient. The prominent degeneration of motor neurons, however, must also have played a role in the clinical picture. Some patients with the syndrome of a multifocal motor neuropathy may have MND rather than, or in addition to, a demyelinating peripheral motor neuropathy.

Action Potentials↗
PubMed1996

[Experimental infection of Glossina morsitans morsitans (Mall) with Trypanosoma congolense (ZRE/G143/90). Parasite cycle and vector competence in the tsetse fly].

This report presents an experimental study of the life cycle of Trypanosoma congolense (ZRE/G 143/90) in relation to the vectorial competence of Glossina morsitans (Mall). The rate of engorgement at the time of an infectious meal and the mortality before day 15 of the life cycle were not significantly different between male and female flies. The mesocyclic forms of trypanosomes were regularly observed in the proventriculus, crop duct, oesophagus, cibarium and proboscis, except in the crop. On day 12 of the cycle, epimastigote forms were predominant in the proboscis. On day 13 of metacyclogenesis, four out of six rats (67%) used for feeding the flies were positive for trypanosomes upon buffy coat examination. These results demonstrate the short incubation period of trypanosomes in the vertebrate host and precociousness of the vectorial competence of some individuals of G m morsitans (Mall). Among the three cyclic stages, only the procyclic forms in the intestine showed a significant difference between the sexes, the male flies being more infected than the females. Metacyclogenesis undergoes three cleavages leading to the successive and permanent establishment of the procyclic, mesocyclic and metacyclic forms in the midgut, proventriculus and proboscis respectively.

Animals↗
PubMed1995

Effect of a fermented infant formula containing viable bifidobacteria on the fecal flora composition and pH of healthy full-term infants.

We assessed the growth, tolerance, and acceptability as well as fecal flora composition and stool pH of 20 healthy full-term infants fed with a fermented whey-adapted infant formula containing viable bifidobacteria (10(6)/g of powder) during the first 2 months of life. This fermented infant formula, first biologically acidified by Streptococcus thermophilus and Lactobacillus helveticus, was compared to a whey-adapted, nonacidified, low-phosphate infant formula in a double-blind, randomized controlled study. The results were compared to a control group (n = 14) of fully breast-fed infants. The fermented whey-adapted formula containing viable bifidobacteria induced a prevalence of colonization with bifidobacteria at 1 month of age similar to that of breast-fed infants (12/20 versus 8/14) but significantly higher than in the group fed the standard infant formula (4/20). The mean bacterial count of bifidobacteria was similar in all colonized infants; however, fecal pH was significantly lower in the breast-fed infants than in the nonacidified bottle-fed infants. This kind of infant formula was well tolerated and promoted a normal growth during the first 2 months.

Bifidobacterium↗
PubMed1995

[Standardization and evaluation of a manual salivation method for the detection of Trypanosoma infection in the tsetse fly (Diptera: Glossinidae)].

Two methods of salivation of tsetse flies, namely manual salivation and method of Bruce et al. were simultaneously evaluated on 1,702 male uninfected Glossina palpalis palpalis (Zaire), G. palpalis gambiensis (Bobo-Dioulasso), G. p. gambiensis (Maisons-Alfort) et G. morsitans morsitans (Mall) fasted for 23, 48 and 72 hours. The risk of salivation was 0.66 by the manual method and 0.01 by the method of Bruce et al. The manual salivation method was standardised on 79 male G. m. morsitans (Mall) infected with Trypanosoma congolense IL 1180. By this method, 70.88% of flies carrying mature and/or immature infection were identified. A clear difference was observed in the proportion of tsetse flies which salivated after 72 hours and those which salivated after 48 and 24 hours of fasting.

Animals↗
PubMed1992

Further evidence for myelinated as well as unmyelinated fibre damage in a rat model of neuropathic pain.

A mononeuropathy, produced by ligation of the sciatic nerve in rats, has recently been proposed as an animal model of experimental pain and pain-related disorders (hyperalgesia and allodynia). We investigated quantitatively the morphological changes in myelinated and unmyelinated fibres of the sciatic nerves 2 weeks after ligation in rats exhibiting allodynia to thermal stimulation. There was a marked reduction in the number of large myelinated fibres distal to the ligature (711 +/- 34 compared with 5315 +/- 230 in normal nerves). We also found a significant loss of small myelinated fibres (2429 +/- 109 compared with 3197 +/- 308 in normal nerves), the remaining fibres of this type showing pathological properties. Finally, ultrastructural evidence of damage to unmyelinated fibres was found. The typical pattern of large clusters of normal unmyelinated axons was no longer present within most regions of the nerve. There was a significant reduction in the size of the unmyelinated fibres (0.41 micron +/- 0.15 compared with 0.71 micron +/- 0.08 in normal nerves), together with a twofold increase in their number per cluster. Hypotheses about the mechanism of thermal allodynia in this pain model therefore must take into account the fact that all fibre classes show pathological changes.

Animals↗
PubMed1991

Magnesium deficiency as a cause of acute intractable seizures.

Clinical and experimental investigations have shown that magnesium depletion causes a marked irritability of the nervous system, eventually resulting in epileptic seizures. Although magnesium deficiency as a cause of epilepsy is uncommon, its recognition and correction may prove life-saving. Two case reports are presented which emphasize the importance of recognizing hypomagnesaemia in patients with acute intractable seizures.

Adult↗
PubMed1991

[Vectorial capacity of Glossina palpalis gambiensis (Bobo Dioulasso) for Trypanosoma brucei brucei EATRO 1125].

A total of 440 teneral Glossina palpalis gambiensis received one single bloodmeal on a guinea pig infected chronically with Trypanosoma brucei brucei EATRO 1125. Metacyclic infections were present in 11.29% of the flies, in 2.32% infections were limited to procyclical stages. No significant difference in vectorial capacity was observed between male and female flies, the level of metacyclic infections being 13.19% in the former and 9.55% in the latter. The parasitaemia level, the percentage of stumpy forms at the moment of the blood meal and the maintenance conditions of the flies seemed to influence the infection of the flies.

Animals↗
PubMed1990

Polyneuropathy in lithium intoxication.

Two patients developed acute sensorimotor polyneuropathy after intoxication with lithium carbonate. Nerve conduction studies, electromyography, and sural nerve biopsy proved it to be an axonal neuropathy. Recovery of muscle strength, reflexes, and sensory function started weeks after discontinuation of lithium therapy. One patient fully recovered within a year. In the literature we found nine other cases of lithium polyneuropathy.

Adult↗