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Biomedical subjects

J J Mooij

Publications and source records attributed to J J Mooij.

32 records · Page 2Linked to original sources

Progressive neurological deficit in children with spina bifida aperta.

The results of re-operation of 15 patients with spina bifida aperta are reported. The operation was necessary because of neurological deterioration with increasing motor and bladder dysfunction. In all patients a tethered cord syndrome was present (CT-myelography). The myelum was adherent to the scar of the myelomeningocele repair. At operation the myelum is released from the adherent scar and in this way untethered. The early complications were mild except for one patient with decompensation of hydrocephalus. The aim of the operation was to stop further progression. The results of the operation were satisfactory with stabilisation of motor function in four patients and improvement of motor dysfunction in ten patients. Backache or fixation, bladder dysfunction and abnormal foot shape improved in some of the patients. In our experience the operative untethering procedure was useful. Intensive neurological control of operated spina bifida aperta patients is mandatory especially in those patients who can walk.

Adolescent↗

The cause of failure in high cervical percutaneous cordotomy: an analysis.

Factors that might have contributed to failure of high cervical percutaneous cordotomy in 23 patients with intractable pain were investigated. Cordotomy failed in 3 patients, 20 had initially good pain relief (87%). True recurrence occurred in 5 patients, 3 of them developed pain elsewhere. Analysis of these three types of failure showed a purely technical cause in 2 cases; other failures or recurrences were due to the underlying disease being not strictly unilateral, or possibly to the existence of other ascending pathways carrying nociceptive impulses apart from the spinothalamic tract. There was no influence of age, sex, type of cancer or previous medication on the result of percutaneous cordotomy. Patients with plexus involvement did better than those with bone metastasis.

Aged↗

Ulnar nerve pathology at the elbow: the place of anterior transposition today.

A retrospective study is presented of 39 patients with ulnar nerve pathology at the elbow. All patients were treated by anterior transposition. Improvement to at least good functional recovery occurred in 46% of the patients. In the other 54% there was only slight or no improvement, or even deterioration. A further analysis of the results showed that in patients with objective signs of ulnar pathology, but without muscular atrophy, the results were good: 64% of these patients showed a good operative result. The most important factors in postoperative prognosis in the patients studied are the existence of muscular atrophy, age, and, in the moderately severe group, the length of history before operation. The aetiology was not important with respect to the outcome. On the basis of the recent literature and the results of this study suggestions are presented for a rational choice between the different possibilities of treatment for ulnar nerve pathology at the elbow.

Adult↗

[Arachnoiditis].

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Arachnoiditis↗

Spinal arachnoiditis: disease or coincidence?

In 86% of 63 patients with spinal arachnoiditis the localization was lumbosacral, and in 14% it was cervical or thoracic. The most important aetiological factor was the combination of one or more myelographies with one or more operations. It is remarkable that in most patients with lumbosacral arachnoiditis the clinical picture did not show new or typical signs of arachnoiditis, but was the same as before the arachnoiditis had developed. In only 20% of patients with lumbosacral arachnoiditis, and in all patients with cervical or thoracic arachnoiditis, did new signs and symptoms occur concomitantly with and due to the development of the arachnoiditis. The results of this retrospective study suggest that lumbosacral arachnoiditis is a coincidental finding in the majority of cases, without clinical consequences.

Adolescent↗

Potassium induced potential changes in rat diaphragm muscle.

The effect of different potassium concentrations on the membrane potential and membrane resistance of rat diaphragm muscle fibres was measured by means of a double sucrose gap method and a microelectrode technique. Concentration measurements showed that the muscle fibres gained sodium and lost potassium in the equilibration period. In the absence of external chloride changing the external potassium concentration from 2.8 mM to potassium-free caused a depolarization of the membrane of about 30 mV and a small increase in membrane resistance. This K-dependent potential change (K-response) was induced by ouabain, K-strophanthin, 2,4-dinitrophenol and cyanide, indicating that an energy requiring process is involved. The temperature dependence of the K-response found is consistent with this assumption. Variation in potassium permeability in the absence and presence of external potassium could account for only 13% of the K-response. The K-response amplitude appeared to depend on the external potassium and the internal sodium concentration. Hyperpolarization of the membrane could not only be produced after readmission of potassium but also after addition of thallium, the latter being more potent. Raising the external chloride concentration resulted in a decrease of the K-response and membrane resistance. The current, generating the K-response was shown to be hardly influenced by conditional polarization of the membrane. It is concluded from these results that the K-response is mainly due to the operation of an electrogenic sodium pump.

Animals↗

The masking role of the sodium pump and chloride ions on the effect of carbachol in- and outside the endplate region of rat diaphragm muscle.

The effect of carbachol (10(-3)M) on the membrane potential of rat diaphragm muscle fibres near and remote from the endplate has been investigated by means of a microelectrode technique. In the endplate region a rather slow depolarization was observed followed by spontaneous repolarization. Outside the endplate region similar, but smaller, responses could be measured. In a muscle part separated from the endplate zone, carbachol had no depolarizing effect. Inhibition of the sodium pump by ouabain (10(-4)M) or potassium-free medium not changing the membrane potential itself, allowed carbachol to exert a depolarizing effect on this endplate-free membrane, while in endplate-free regions continuous with the endplate-zone the depolarizations already observed were enhanced. In low chloride solutions carbachol also had a depolarizing effect on endplate-free muscle membrane. It is concluded from these experiments that a direct effect of cholinergic drugs on endplate-free muscle membrane of rat diaphragm is counteracted by the sodium pump in combination with passive chloride movements. The results are discussed in the context of known receptor densities and chloride effects.

Animals↗

Influence of chloride and sodium pump activity on carbachol- and acetylaholine-induced depolarizations in denervated rat diphragm.

The effect was measured of low chloride medium and ouabain on carbachol- and acetylcholine-induced depolarizations in denervated rat diaphragm. Membrane potentials were measured in rat diaphragm muscle fibers 10-14 days after denervation. Depolarizations induced by carbachol and acetycholine were increased when the extracellular chloride concentration was diminished from 110 to 40 or 10 mM. Sodium pump inhibition by ouabain (10(-4) M) dramatically enhanced the carbachol depolarizations. In 40 mM Cl- solutions, dose-response relations were determineed with ACh in the absence of presence of dTc. For ACh a pD2 value of 5.2 was found; the pA2 value for dTC appeared to be about 6.4. Therefore, the binding properties of the post-denervational receptors do not appear to be influenced by the chloride gradient. It was concluded that drug-induced depolarizations of the denervated rat diaphragm are short-circuited by chloride ions and counteracted by sodium pumping.

Acetylcholine↗

The interaction of acetylcholine and d-tubocurarine on the end-plate free muscle membrane of rat diaphragm in low chloride solution.

The interaction of acetylcholine (ACh) and d-tubocurarine (dTC) on the membrane potential of end-plate free parts of rat diaphragm muscle fibres was studied using a conventional microelectrode technique. ACh only caused membrane depolarizations when the external chloride concentration was diminished. Therefore, all experiments were performed in a 40 mM Cl- containing medium. A bell-shaped log-dose response curve was obtained with ACh. Maximal depolarization occurred at 3.10(-4) M. The pD2 value for ACh was calculated to be 4.2. The log-dose response curve was shifted to the right in the presence of dTC; besides, the maximum seemed to be depressed. The pA2 values for dTC appeared to be 4.9. It was concluded from these data that the cholinergic receptors outside the end-plate region have binding properties, which differ considerably from those of end-plate or postdenervational receptors.

Acetylcholine↗