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Biomedical subjects

B Williams

Publications and source records attributed to B Williams.

At least 469 records · Page 26Linked to original sources
PubMed1981

Differential effects of neuroleptic agents on the pituitary-gonadal axis in men.

Previous studies showing inconsistent effects of neuroleptic agents on the pituitary-gonadal system suggest that the drugs may differ in their effects on this system. Serum testosterone, luteinizing hormone (LH), prolactin, and neuroleptic levels were measured in 42 male schizophrenic patients during long-term treatment with thioridazine hydrochloride, trifluoperazine hydrochloride, chlorpromazine hydrochloride, and other neuroleptic agents and in six drug-free patients. Serum testosterone and LH values were significantly lower in patients taking thioridazine than in those taking other neuroleptic drugs. The relatively high serum neuroleptic levels in patients taking thioridazine may account for its differential effect on the pituitary-gonadal system.

Adult↗
PubMed1981

Simultaneous cerebral and spinal fluid pressure recordings. I. Technique, physiology, and normal results.

Cerebrospinal fluid pulsation is likely to be responsible for the progression of some diseases, and it is differences in pressure which are significant in causing the imposition of energy upon tissues. The normal range of such differences has not been extensively documented. A technique for measuring intracranial and intraspinal pressures simultaneously in erect conscious patients is described. Normally the pressures are in a continual state of pulsation in response to changes in pressure in the arteries and veins. The measurements of CSF pressure fluctuations in response to normal cardiac pulsation, respiratory changes, coughing, Queckenstedt's test, and a variation of Valsalva's manoeuvre have been recorded, and the physiology has been discussed.

Brain Diseases↗
PubMed1981

Simultaneous cerebral and spinal fluid pressure recordings. 2. Cerebrospinal dissociation with lesions at the foramen magnum.

Simultaneous intraventricular and intraspinal pressure recordings in erect patients with obstructive lesions of th CSF pathways reveal differences in pressure which are frequently transitory and produced by pulsation. In non-acute cases without papilloedema but with suspected hindbrain hernia delay in equalization after pressure pulses may be demonstrated, and after Valsalva's manoeuvre differences between the head and the spine may be generated transiently and be responsible for clinical symptomatology. The particular clinical features related to hindbrain hernia are syringomyelia, cough headache, cough syncope, and lower cranial nerve signs with oscillopsia and cerebellar ataxia. Correction of the pressure dissociation is often associated with marked clinical improvement. It is suggested that this form of testing may be of relevance as an indication for operation and also for monitoring the progress of post-operative patients.

Brain Diseases↗
PubMed1981

Syringomyelia as a sequel to traumatic paraplegia.

Ten cases of post-traumatic paraplegia are described in whom syringomyelia symptoms have supervened. Five patients have been operated upon after investigation. Operative results have been encouraging. A discussion of likely pathogenetic mechanisms is presented.

Adolescent↗
PubMed1981

A case of high-pressure intracerebral pouch.

A case is presented of a 13-year-old boy with a long-standing high-pressure pouch in the right parietal lobe containing cerebrospinal fluid. The clinical presentation was of epilepsy. Isotopic studies suggested that the pouch was filling along the subarachnoid space at the back of the corpus callosum in the posterior part of the interhemispheric fissure. There was a dilated sulcus at this point, which filled freely on air encephalography. Pressure studies suggested the likelihood of a venous pulsation filling mechanism with a valvular action. Electrocorticography, excision of an epileptic focus in the wall of the cavity and opening of the ventricular wall into the pouch have produced a good clinical result. Computerized tomography after operation has confirmed correction of the high-pressure state.

Adolescent↗
PubMed1981

Treatment of subdural empyema.

A review of 66 cases and a survey of the literature indicates that survival rates of around 90% should now be expected from patients with subdural empyema. Factors affecting the outcome are discussed. In addition to prompt surgical treatment and appropriate antibiotic therapy, the most important step seems to be extensive craniotomy and direct removal of subdural pus, particularly from the interhemispheric fissure. Treatment through burr holes is not acceptable. In the absence of a culture of the organisms and known antibiotic sensitivities, chloramphenicol is recommended as the drug of choice.

Adolescent↗
PubMed1981

Murine T cells that lyse antibody-sensitized target cells. III. Contribution of Thy 1-Bearing cells to the lytic activity of normal spleen.

Murine spleen cells were analysed for their capacity to lyse 51Cr-labelled antibody-sensitized erythrocytes and a human lymphoma cell line. Incubation of spleen cells with iron powder followed by removal of iron-containing cells with a magnet significantly decreased the lytic capacity of the remaining cells against erythrocyte target cells. However, substantial cytotoxicity remained in the relatively phagocyte-depleted population. Both antibody-sensitized erythrocytes and tumour cells were lysed by phagocyte-depleted effector cells. However, more spleen cells were required to lyse nucleated target cells than were required to produce comparable lysis of the erythrocytes. Such phagocyte-depleted spleen cells were subsequently treated with three different antisera containing specificities for thymus-dependent antigens and a monoclonal IgM anti-Thy 1.2 in the presence of complement. The remaining viable cells were recovered and tested as effector cells. All four reagents in the presence of complement caused an inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC) that was proportional to the percentage of T cells eliminated. However, the antisera also inhibited ADCC in the absence of complement, even when the cells were trypsinized following the antiserum treatment to remove attached antibodies. On the other hand, treatment of spleen cells with the monoclonal IgM anti-Thy 1.2 followed by trypsin treatment did not inhibit ADCC unless complement was added. Thus, with the latter reagent, decreased ADCC could be ascribed to elimination of T cells and not immune complex inhibition. Cells bearing Thy 1.2 accounted for approximately half of the lytic activity of phagocyte-depleted spleen cells against antibody-sensitized target cells.

Animals↗
PubMed1981

Chronic herniation of the hindbrain.

Herniation of the hindbrain occurs when the lowest parts of the cerebellum and sometimes part of the medulla are moved downwards through the foramen magnum, a pressure difference acting across the foramen magnum moulding the tissues into a plug. It is suggested that the clinical course in both adults and babies with spina bifida may be explained by the hindbrain hernia acting as a valve.The term 'Chiari Type I deformity' is commonly used for an abnormality in which the tonsils and lowermost parts of the cerebellar hemispheres are prolapsed through a normal foramen magnum. Acute herniation may occur as a result of space-occupying lesions. Chronic herniation may be morphologically identical although it tends to be more severe. Sometimes it will produce few symptoms which often may be delayed so that the original causative lesion may not be apparent. Causes include bone softening, tumour, or previous meningitis. Birth injury is probably the commonest cause of the deformity, which presents clinically in adults.In infants with severe forms of spina bifida a hindbrain herniation is present. This abnormality may be called 'Chiari Type II deformity' or Arnold-Chiari deformity and is an intra-uterine abnormality in which the fourth ventricle and medulla are grotesquely herniated before they are properly developed and the foramen magnum is enlarged.The commonest clinical presentation of Chiari Type I deformity is syringomyelia, which is usually not diagnosed until adult life. Other presentations include syringobulbia, headache, oscillopsia, attacks of giddiness, lower cranial nerve palsies, and ataxia. Particularly characteristic are cough headache and cough syncope. Syringomyelia and syringobulbia in particular may be irreversible by the time they are diagnosed. Nevertheless, surgical decompression may be successful in relieving symptoms of headache, cough syncope, and long-tract compression; most cases of syringomyelia show some improvement and in others progression of the disease is arrested. Operative techniques for hindbrain herniation are discussed.Chiari Type II deformity is probably responsible for the progression of hydrocephalus after birth in the majority of babies with spina bifida. Measurement of pressure in the cerebrospinal fluid above and below the foramen magnum shows that intermittent pressure difference is commonly present at times of neurological deterioration. Surgical decompression of the hernia in adults allows correction of the valvular effect, which may be monitored by pressure measurements. In babies the associated hydrocephalus is usually so gross that it requires separate treatment, but pressure monitoring may be of value in assessing the state of the disease.

Adult↗
PubMed1981

A comparison of three liquid-ventilation cooling garments during treadmill exercise.

Tests were performed on five male subjects to compare the heat transfer performance and physiological effects of three different cooling garments when used under a sealed, impermeable garment which simulated a space suit. The mean exercise metabolic rate while walking at 0.9 m/s (2 mph) was 464 +/- 33 W. An equilibrium condition was never reached during the uncooled suited control runs and the subjects lost a mean of 1.12 +/- 0.15 kg (2.5 +/- 0.3 lb)--approximately 2% of body weight--during exercise. The mean weight loss was 0.35 +/- 0.10 kg (0.8 +/- 0.2 lb) with an Apollo-type garment; 0.26 +/- 0.11 kg (0.57 +/- 0.24 lb) with the full-body cooling patch (garment 2); and 0.52 +/- 0.12 kg (1.15 +/- 0.26 lb) with the partial-coverage cooling patch (garment 3). Impedance plethysmography data showed an increase in leg blood flow when the working muscles were not cooled by liquid flow (garment 3), and the arm blood flow remained unchanged whether or not there was liquid cooling to the arms.

Adult↗
PubMed1980

Cough headache due to craniospinal pressure dissociation.

Two women had severe headache that would come on a few seconds after straining or coughing and would last for about a minute. Results of pressure studies showed that a difference in pressure between the ventricles and the lumbar subarachnoid space developed after coughing or straining. Decompression of the cerebellar tonsils relieved the symptoms and eliminated the craniospinal pressure dissociation in both cases.

Adult↗
PubMed1980

Radiographic studies of the ventricles in syringomyelia.

Radiographic investigations of 171 patients with "communicating' syringomyelia have been reviewed. Hydrocephalus was found in one-third of the cases and has occasionally progressed after operation on the posterior fossa, sometimes with accompanying clinical deterioration. The outlets of the fourth ventricle were usually abnormal; tonsillar descent, arachnoiditis and both together were seen. Arachnoiditis correlated strongly with a history of difficult birth. The foramen of Magendie was sometimes patent and sometimes blocked. There was no consistent level of occlusion corresponding to a persistent roof of the fourth ventricle. The cisterna magna was usually small or obliterated but some examples of large cisterns or subarachnoid pouches were found. Radiological demonstration of a communication from the fourth ventricle to the syrinx occurred in only seven patients by positive contrast material and not by air. It is suggested that a sizable communication is rare at the time when patients seek treatment.

Adult↗
PubMed1980

Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 1. Morphology.

Intracisternal kaolin injection in dogs usually produces hydrocephalus and out of 16 such dogs 11 have shown enlargement of the central canal of the spinal cord which has proceeded to syringomyelia-like cavities in 7 instances. The morphology of the cavities is described, the absence of ischaemic changes in the cord noted and the occasional communication of the cavities with the spinal subarachnoid space at the level of the filum terminale confirmed. The similarities to human syringomyelia are noted together with important differences in the etiology. The dogs all had arachnoiditis, all had hydrocephalus and all had a radiologically demonstrable communication of the cavities with the 4th ventricle, findings which are unusual in human syringomyelia.

Animals↗
PubMed1980

Experimental communicating syringomyelia in dogs after cisternal kaolin injection. Part 2. Pressure studies.

Pressure measurements in cerebrospinal fluid have been made from the ventricles and the spinal subarachnoid space in dogs made hydrocephalic by intracisternal injections of kaolin. Raised intraventricular pressure has been confirmed in the confirmed in the ventricles. The spinal pressure is usually markedly different from that in the head, confirming that the arachnoiditis produced around the cistern isolates the spinal subarachnoid space from the CSF in the head. Pulsatile pressures have been investigated specifically and the interrelationship between the pulsation and baseline pressures in the development of communicating syringomyelia discussed. There are differences between these experimental animals and the human disease, particularly in the baseline pressures which are usually equal in the head and the spine of humans at rest even in cases with syringomyelia.

Animals↗
PubMed1980

Blood-gas tension measurement in anaesthesia by bubble equilibration and mass spectrometry.

If a small bubble gas is equilibrated with a volume of blood the partial pressures of the components of the bubble after equilibration approximate to the original tensions in the blood. A method is described in which the bubble is analysed by a respiratory mass spectrometer connected to a mini-computer. The normal respiratory monitoring function of the mass spectrometer need be interrupted for only 20 s for each sample and the complete equilibration and analysis procedure takes only 3 min. Theoretical studies, experimental tests and records of experimental usage show that, in a subject anaesthetized with halothane in nitrous and oxygen, tension can be measured with an overall SD of 5% for carbon dioxide and halothane and, certain reservations, an SD of about 3% for nitrous oxide.

Anesthesia, Inhalation↗