PubMed Health⌕ Search

Biomedical subjects

K C Wilson

Publications and source records attributed to K C Wilson.

30 records · Page 2Linked to original sources
PubMed1983

Passive membrane properties of neurones in the dorsal raphe and periaqueductal grey recorded in vitro.

A slice preparation of the rat mesencephalon containing the dorsal and medial raphe nucleus, the periaqueductal grey, the superior colliculi and the reticular formation is described. Intracellular recordings showed marked differences in the passive membrane properties of neurones of the dorsal raphe. Serotonin-containing neurons were characterized by a high membrane input resistance, a very long time constant and by the presence of membrane rectification only in a very hyperpolarized (less than -120 mV) region of their voltage-current relationship. In most of the neurones in and around the dorsal raphe area a brief pulse of depolarizing current was followed by a pronounced after-hyperpolarization, which appeared to be mediated by the activation of a Ca2+ dependent-K+ conductance.

Action Potentials↗
PubMed1983

A study of patellofemoral plain in a junior infantry training unit.

The incidence of patellofemoral pain in a Junior Unit was assessed retrospectively over a 4 year period and prospectively by studying an annual intake of recruits during their initial training year. An average of 3.5% per intake were found to have been discharged due to the disease between 1977 and 1980. 4.5% of the intake prospectively studied were discharged and 75% of those presenting with symptoms were cured. The clinical characteristics of recruits presenting with the the disorder were prospectively studied in a controlled, blind, consecutive series of 45 patients. Two groups of characteristics were identified; those with an early, insidious onset in training, a pre-Service history and a poor response to physiotherapy and those with an acute, traumatic onset, presenting later in training and responding well to physiotherapy. The aetiology of patellofemoral pain in a Junior Recruit is discussed and attention drawn to specific problems encountered by these patients.

Cartilage Diseases↗
PubMed1980

Age-related changes in the neurosensory epithelium of the mouse vomeronasal organ: extended period of postnatal growth in size and evidence for rapid cell turnover in the adult.

The total number of neurosensory cells in the mouse vomeronasal organ was estimated during postnatal development by counting the cell density and measuring the total volume of the neurosensory cell layer. There is a 43% increase in neurosensory cell number between 1 and 4 months of age, followed by a 21% fall in cell number between 4 and 8 months. There is no further significant change in cell number between 8 and 18 months of age. Cell division was shown to be occurring in the vomeronasal organ of animals at 7 months of age by labelling dividing cells with [3H]thymidine continuously administered by means of implanted 'osmotic pumps'. At least 1 in 6 cells were labelled by 12 days of thymidine administration, indicating a turnover time of 2--3 months for the whole epithelium. This raises the general problem of how a fixed central nervous system accommodates a changing peripheral input.

Age Factors↗
PubMed1980

Improved exercise performance after exchange transfusion in subjects with sickle cell anemia.

Ten patients with sickle cell anemia underwent partial exchange transfusion with hemoglobin-A-containing cells using a technique that allowed hemoglobin concentration and blood volume to remain constant. The mean fraction of hemoglobin-A in these patients increased from 9% to 55%, but the mean hemoglobin concentration increased by only 1.44 g/dl. The exchange resulted in a large improvement in submaximal exercise capacity: the mean of the anaerobic threshold (the work at which lactic acid begins to accumulate in the blood) increased from 68 to 114 W. The mean work performed at a heart rate of 170/min, an estimation of maximal work capacity, increased from 128 to 187 W. Improved exercise performance after partial exchange transfusion may result from the superior flow properties of hemoglobin-A-containing red cells. Furthermore, we believe that exercise testing in sickle cell anemia has great potential utility as a means to monitor therapy and to evaluate the benefits of exchange transfusion.

Adult↗
PubMed1979

The limitation of pulsatile flow through the aqueduct of Sylvius as a cause of hydrocephalus.

The concept is advanced that hydrocephalus results from limitation in the pulsatile flow of CSF downwards through the aqueduct of Sylvius during systole which is necessary to accommodate for the pulsatile pressure and volume increase that accompanies the propagation of the arterial pulse through the brain. Evidence is given to show that flow through the fixed human aqueduct is disturbed and not laminar. Further, with the pressures availalbe, the aqueduct is only just large enough to pass the quantity of fluid which must be vented extracranially during systole. Should the capacity of this systolic venting mechanism be exceeded, physical strain will cause cellular damage in the periventricular and periaqueductal regions which, if prolonged, will lead to tissue destruction and hydrocephalus. There appear to be two main causes for hydrocephalus resulting from this mechanism. Firstly, structural lesions, restricting the lumina of the CSF-venting pathways, especially the aqueduct, will reduce the volume of CSF that can flow through these pathways during systole. The hydrocephalic process will then be continuous and only limited when tissue destruction reduces the systolic volume expansion of the brain such that it can be accomodated by the restricted CSF venting pathways. Secondly, conditions which may increase the amount of the systolic volume expansion of the brain beyond the capacity of the CSF venting pathways. Raised mean intracranial pressure is the most important of these conditions. In such cases the hydrocephalus will be limited by the duration of the causal process and possibly also by the enlargement of the venting pathways, as a result of tissue destruction. This hypothesis also accounts for hydrocephalus resulting from obliteration of the cortical subarachnoid space, obstruction to the cranial venous drainage, deformities in the region of the foramen magnum and arterial encroachment upon the ventricular system.

Acidosis↗
PubMed1978

Emergency department key factor in hospital admissions.

A significant proportion of a community hospital's inpatient population is admitted through the emergency department. Administrators who are aware of the frequency of this practice in their institutions can schedule and staff services more efficiently. A 1975 survey conducted by the American Hospital Association shows that the number of emergency department admissions depends on hospital size, location, ownership, and type of physician coverage in the emergency department.

Contract Services↗
PubMed1978

Arginine vasopressin metabolism in dogs. II. Modeling and system analysis.

System modeling and analysis methods were applied to interpret data regarding arginine vasopressin (AVP) metabolism in dogs. Based on this analysis a new nonlinear 3-pool model of AVP distribution and disposal was proposed and quantified; the model pools included the plasma, a receptor pool, and an extravascular nonreceptor pool. The receptor pool mediated a portion of the rapid flux of hormone between the plasma and the extravascular pool. Mathematical analysis indicated that the plasma AVP impulse response (bolus) data would be insufficient to uniquely estimate all the model constants, but additional plasma impulse data using 125I-labeled AVP, which does not bind to physiologic hormone receptors, would allow unique model quantification. Other required measurements were the urinary excretion of intact hormone, and plasma AVP degradation. The model was successfully fitted to the data from 10 dogs. The results suggest that, in the normal dogs studied, plasma contained 25% of the total AVP, 19% was bound to receptors, and the remaining 56% was in the extravascular pool. Eighty percent of the flux of AVP from the vascular compartment was mediated by the receptor pool; 98% of AVP degradation occurred in the extravascular pool; and urine excretion and plasma degradation made up the remainder.

Animals↗