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Biomedical subjects

K G Go

Publications and source records attributed to K G Go.

At least 91 records · Page 5Linked to original sources
PubMed1981

The permeability of the blood-brain barrier in acute hypertension. Comparison of an endogenous and exogenous protein tracer.

Experimental acute hypertension in male Wistar rats was produced by metaraminol infusion to systemic blood pressure levels of 190-210 mm Hg. After 20 sec or 30 min the animals were killed by perfusion fixation with 8% formaldehyde perfusion. The barrier passage of exogenous HRP (75 mg i.v.) given 10 min before killing (5 rats) and the passage of endogenous anti-HRP antibodies of the IgG class (8 rats, produced by antigenic stimulation beforehand) were compared electron microscopically by semiquantitation of tracer location in unstained ultrathin sections. Five rats served as controls. The number of tracer-filled vesicles was consistently lower in anti-HRP rats than in HRP rats: not only during acute hypertension but also in the controls. The penetration of both tracers into the basement membrane and brain parenchyma, however, was comparable. Anti-HRP was more prominent in the endothelial cytoplasm. Vesicular transport and penetration through the plasma membrane with diffuse cytoplasmic passage tend to be the most likely transport mechanisms, the former for HRP and the latter for the antibody.

Animals↗
PubMed1981

Experiences with recurring ventricular catheter obstructions.

Seven cases are presented of recurrent ventricular catheter obstruction, an infrequent but serious problem in the management of hydrocephalus. Plugging of the catheter was caused by detritus rather than by choroid plexus. A retrospective analysis of 214 shunt revisions indicated that obstruction both by detritus and by choroid plexus were incidental phenomena in the great majority of the cases - the former type occurring mainly within the first month, the latter between 3 and 6 months after operation. It is suggested that the ultimate cause of recurrent catheter obstruction by detritus may be destruction or ablation of the ependymal lining of the ventricles (e.g. by an inflammatory process), which easily provides debris to the catheter. In 4 of the cases insertion of the catheter into the opposite ventricle prevented further recurrence, when reinsertion into the same ventricle had been ineffective. In one case, with scarcely dilated ventricles, external decompression was helpful. In patients with compartmentalisation of the ventricles (substantiated in one of our patients) one might consider removal of the septa via craniotomy before the insertion of the catheter.

Cerebrospinal Fluid Shunts↗
PubMed1980

The effect of cold-induced brain edema on cerebrospinal fluid formation rate.

The net contribution of vasogenic brain edema to cerebrospinal fluid (CSF) formation was studied by ventriculocisternal perfusion. Individual cats were perfused both before and 2 1/2 hours after a severe cold-induced injury to the cerebral cortex, and the results were compared. Although the edema had occupied the larger part of the hemispheric white matter and bordered the lateral ventricle, a decrease rather than an increase in CSF formation rate was observed. This decrease was related to a decrease in the cerebral perfusion pressure by a regression equation that was not affected by the cold injury.

Animals↗
PubMed1980

[Brain edema evolution (author's transl)].

Brain edema of the vasogenic type is being discussed in its subsequent stages of exudation, spreading and resolution; and particularly the pathophysiological mechanisms which are involved in these stages.

Blood Pressure↗
PubMed1979

The effect of intracerebral ouabain administration on the composition of edema fluid isolated from cats with cold-induced brain edema.

Brain edema fluid was collected from cats with a freezing lesion in the left parietal cortex by the insertion into the brain of needles containing nylon wicks and connected to polyethylene tubes. The edema fluid samples which accumulated in the polyethylene tubes were regularly analyzed for Na+ and K+ content, colloid osmotic pressure, lactate dehydrogenase and creatine phosphokinase activity, and 99mTc-albumin radioactivity; the albumin tracer being introduced intravenously at the time of cold-injury. One series of cats received an intracerebral injection of ouabain solution, the control series an intracerebral injection of saline, at 100 min after the cold-injury. The ouabain injection was followed by an increase of K+ content, LDH and CPK activities but a decrease of Na+ concentration in the edema fluid, attributable to a concentration of solutes in the edema fluid as presumably water and Na+ were shifted into the cells and hence the extracellular space was reduced.

Animals↗
PubMed1979

Brain sodium uptake after choroid plexectomy.

When in a (control) series of rats brain sodium uptake (BSU) -- as calculated from estimated radioactivities of brain and blood following the injection of [24Na]sodium chloride 30 min and [22Na]sodium chloride one minute before killing -- was plotted against average arterial blood pressure of the animals during the 30 min survival period, a linear dependence of BSU on blood pressure was observed. In another series of animals, in which the choroid plexuses of the fourth and both lateral ventricles had been removed, the regression line showed the same slope, but a significantly lower intercept. On the other hand, a series of rats which had been subjected to a sham operation without removal of the choroid plexuses, showed a regression line not different from the control series. The results indicate that probably the blood pressure independent component of brain sodium uptake, as represented by the intercept of the regression line, for the greater part constitutes cerebrospinal fluid secretion by the choroid plexus.

Animals↗
PubMed1979

Composition of isolated edema fluid in cold-induced brain edema.

Edema fluid isolated from cats with cold-induced brain edema was subjected to analysis of electrolyte content, enzyme activities, colloid osmotic pressure and the radioactivity of intravenously injected 99mTc-labeled albumin. The findings corroborate the essential features of vasogenic edema, such as its origin from the blood plasma, its rapid propagation into the white matter of the brain as contrasted with the delayed spread into gray matter, and its contribution to composition of cerebrospinal fluid. Moreover, the elevated activities of cellular enzymes and K+ content of edema fluid point to the admixture with cellular contents due to the freezing damage.

Albumins↗
PubMed1979

Influence of hypoxia on the composition of isolated edema fluid in cold-induced brain edema.

The isolation of edema fluid from cats with cold-induced cerebral edema allowed the study of changes of Na+ and K+ content, lactate dehydrogenase and creatine phosphokinase activity, colloid osmotic pressure and the level of intravenously administered 99mTc-albumin in the edema fluid during a period of hypoxia. The changes consisted of an increase of all mentioned parameters, except Na+; and could be interpreted as a concentration of solutes (but for Na+) in the extracellular edema fluid, concomitant to a reduction of the extracellular space, as the oxygen deficiency caused improper functioning of the cellular Na+-K+ pump, with a resulting shift of fluid (including Na+) into the cellular elements.

Albumins↗
PubMed1978

Morphology and origin of arachnoid cysts. Scanning and transmission electron microscopy of three cases.

Three surgically removed primary arachnoidal cysts were studied with scanning electron microscopy (SEM) and two of the cases with transmission electron microscopy (TEM). The cells lining the cyst cavity had microvilli at the surface, true cilia were absent. In the cytoplasm multivesicular bodies, many pinocytotic vesicles, some large vacuoles and strands of tonofilaments were prominent features. The cells were interconnected by desmosome-like junctions and were separated from the surrounding tissue by a distinct but sometimes incomplete basal membrane. Based on these findings it is concluded that arachnoid cysts are derived from the outer arachnoid cells (subdural neurothelium), the formation of the cysts being attributabel to secretory capacity of the subdural neurothelium.

Adult↗
PubMed1977

Intrasacral meningocoele.

A case of an intrasacral meningocoele is described with typical radiological findings and obvious improvement after surgical treatment, but a somewhat unusual neurological picture.

Adult↗
PubMed1976

Experimental cerebral ischemia in Mongolian gerbils III. Behaviour of the blood-brain barrier.

The behavior of the BBB in cerebral ischemia was studied in symptom-positive Mongolian gerbils subjected to left common carotid artery occlusion using Evans Blue dye as indicator of BBB injury. The BBB damage was demonstrable grossly by the presence of areas of blue discoloration, and microscopically by the presence of a bright red fluorescent tracer, localized mostly in the neurons. The survey of various groups of animals revealed a direct relationship between the incidence and time of appearance of the BBB lesions and the duration of the ischemic occlusion. This relationship can be interpreted as another example of the previously described "maturation" phenomenon. A relatively late occurrence of the BBB injury in cerebral ischemia, at the time when the affected brain tissue shows severe, edematous histopathologic changes indicates that the brain edema, as the main complication of ischemia, could be regarded as being primarily of the cytotoxic type.

Animals↗