Ten infants with spina bifida cystica were investigated during life by simultaneous ventricular and intraspinal CSF pressure recordings, and 11 post-mortem specimens were studied by means of crystic resin castings of the ventricles. The results indicate marked pressure differentials between the lateral ventricles and intraspinal CSF pathways, which contribute to the moulding of the Arnold-Chiari malformation as a sliding hernia. Similar pressure differentials may exist at the incisura, with moulding of tissues producing blockage of the aqueduct and the subarachnoid pathways. A valvular action was demonstrated, in which baseline pressure differences were exaggerated by the infant's straining (e.g. crying, sucking), and it seems that complete dissociation between the two pressures may develop as a result of periods of partial dissociation. Removal of the meningocele sac increased the peaks in recordings of intraspinal pressure produced by straining. If it is carried out when there is a valvular effect, it seems that it will hasten the onset of established ventriculo-spinal pressure dissociation and uncompensated hydrocephalus by leading to impaction of the Arnold-Chiari malformation in the foramen magnum. The results indicate that even after birth the CSF pathways of babies with spina bifida cystica are in a plastic and changeable condition, with competition between constricting and distending forces. The demonstration that pressures tend to be low in the spine and to become lower before exacerbation of hydrocephalus suggests that all the intracranial manifestations of spina bifida cystica may be due to low intraspinal pressure, which results from initial failure of the neural tube to close during embryogenesis.

Arnold-Chiari Malformation↗

PubMed1975

The chemical control of preoperative anxiety.

Explore the source record for details and available documents.

Adolescent↗

PubMed1975

The psychological control of preoperative anxiety.

Explore the source record for details and available documents.

Abortion, Therapeutic↗

PubMed1975

Expansion of central arachnoid pouches.

Three case of central arachnoid pouches or cysts which are freely in communication with the subarachnoid space and cause hydrocephalus are reported. One case died; the second recovered following transtentorial opening of a huge cystic cavity located between the tentorium and the cerebellum, which opened into the cisterna magna. The patient was well although mentally retarded 6 years later. The third case was treated with a ventriculoatrial shunt and has fully recovered. In these cases, the shape and situation of the pouches are consistent with a processes of upward movement of CSF. In the CSF waves, originating from constant variations of venous pressure, there is an obvious aetiological factor. Even if the hydrocephalus were primary and the pouch secondary, the pouch might contribute to the progression of the former by occasional compression of the aqueduct. This can be another example of the way hydrocephalus leads to its own exacerbation.

Arachnoid↗

PubMed1975

The nerve gap: suture under tension vs. graft.

Conduction velocities and amplitudes of evoked responses were used in experimental models to compare reinnervation through nerve gaps sutured under tension or bridged with nerve grafts. The best results were obtained when end-to-end suture was done without tension. Regeneration through mildly stretched nerve repairs was equivalent to applying a properly tailored graft. Minimal axonal activity was exhibited by severely stretched repair sites.

Axons↗

PubMed1975

Experimental study of a potential anti-asthmatic agent: SCH 15280.

A forced oscillations technique for measuring total respiratory system resistance was used to quantitate the bronchomotor activity of Sch 15280: (5[4-(N-methyl)-piperidylidine]5H-[1]-benzopyrano[2,3,b]-pyridine maleate) and to compare its potency to that of standard bronchodilator agents. By the intravenous route, Sch 15280 was 48 times more potent than aminophylline and 1/78 as potent as atropine in inhibiting methacholine-induced bronchoconstriction in rabbits. In cats Sch 15280 was 1/12 as potent as ephedrine in inhibiting histamine-induced bronchoconstriction and had a greater protective activity against histamine-induced bronchoconstriction and had a longer duration of action than 0.5% solution of isoproterenol. Statistical tests of parallelism revealed a significant difference between the log dose-response curves of Sch 15280 and ephedrine but not between those of Sch 15280, atropine and aminophylline. The results suggest that Sch 15280 can act via, a nonadrenergic mechanism to block both histaminergically and cholinergically mediated responses in the tracheobronchial tree. This pharmacologie profile may have important therapeutic application in the type I immediate hypersensitivity reactions of man.

Adrenergic beta-Antagonists↗

PubMed1974