Cerebral hemodynamics in familial hemiplegic migraine.
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Adolescent↗
Biomedical subjects
F T Jensen
Publications and source records attributed to F T Jensen.
Delayed primary closure. Blood-flow in healing rat skin incisions.
In an earlier study delayed primary closure (DPC) wounds were shown to develop higher biomechanical strength than primary closure (PC) wounds. In order to elucidate the underlying mechanism, local clearance of 133Xenon and thermography studies were undertaken. A paired comparison design with deposits of 133Xenon injected in the wound margins 3 and 4 days postoperatively, and directly into the wound tissue 10, 20 and 60 days postoperatively was used. Very pronounced differences, with higher blood-flows for DPC wounds, were found in the early measurements. In the later measurements there were significant but less obvious differences. With thermography no differences could be detected. It is concluded that DPC wound have a higher blood-flow, especially in the initial wound healing phase. This supports the hypothesis that an increased blood-flowing during early wound healing is beneficial for the development of mechanical strength in the maturing normal scar.
Animals↗
Cerebral blood flow in the acute phase after head injury. Part 1: Correlation to age of the patients, clinical outcome and localisation of the injured region.
In 40 comatose patients with severe head injury, a total of 114rCBF studies were performed with the intraarterial 133xenon washout technique over the most severely injured hemisphere. All patients were subjected to respirator treatment, and mildly sedated with diazepam, chlorpromazine or meperidine. The average values of the regional flow were corrected for changes in PaCO2 by simultaneous measurements of CO2 reactivity. A PaCO2 value of 30 mmHg (4 kPa) was chosen as the reference value. The results indicate that hyperaemia following head injury is a common phenomenon, especially in young victims with supratentorial cortical lesions. The hyperaemic phase can last from some days to several weeks and is of no prognostic significance. In elderly patients with supratentorial cortical lesions, and in patients with mainly brain-stem lesions or diffuse brain lesions a persistent low flow state was observed in the acute phase (first 1-3 days after the injury). This low flow state was also observed 1-2 weeks after the injury if loss of consciousness persisted, but it was of no prognostic significance, as CBF values between 15 and 20 ml/100 g/min were associated with a good recovery.
Adolescent↗
A human and in vitro study on the exchange of water and solutes from soft contact lenses.
Elimination of technetium (pertechnetate in normal saline solution) was studied from various types of contact lenses placed on normal human eyes by means of computer assisted gamma camera using "region of interest technique" with the designated area corresponding to the conjunctival sac. An elimination 4 times slower was found from a highly hydrophilic lens (Scanlens) than from a HEMA-lens (Softlens), 0,5% min and 2.0% min, respectively. From an ultrathin lens (U3-Softlens) was eliminated 2.4% min. Hard lenses did not absorb the isotope. In a laboratory study the lenses were pre-soaked in pertechnetate, blotted and washed at 2 min intervals in 0.5 ml saline. By this procedure 3% min of the technetium was eliminated from Scanlens, 16% min from Softlens and 28%/min from a thin, therapeutic lens (Plano-T). The ratio Softlens/Scanlens was in the human study 4.0 and in the laboratory study 4.9. Radioactivity was very rapidly eliminated from CAB-lenses. A similar study was carried out with radioactive water. More than 100% min was eliminated in the first 10 min followed by a slower elimination from 10-20 min. Then an increased elimination was seen for a few min. This increased elimination was in repeated studies constantly found after 20 min. It was not found in the studies with technetium and labelled leucine.
Conjunctiva↗
Lacrimal pathology evaluated by dynamic lacrimal scintigraphy.
This study of pathological lacrimal systems demonstrated the usefulness and sensitivity of dynamic lacrimal scintigraphy (dynamic use of computer assisted gamma camera). The method was very sensitive; even small lacrimal obstructions caused a distinct change of the outflow curves. This technique complements other tests in lacrimal assessment especially in patients with epiphora and normal conventional tests.
Adult↗
Acquired hydrocephalus. I. A clinical analysis of 160 patients studied for hydrocephalus.
A total of 160 patients suspected of having acquired hydrocephalus were studied either by quantitative isotope ventriculography (QIV) or by lumbar isotope cisternography (LIC). Of these patients, 56 had hydrocephalus. Mental deterioration, gait disturbances, ataxia, spasticity, and incontinence were most frequently present in the hydrocephalic patients, but none of the signs or combinations thereof are pathognomonic of acquired hydrocephalus. These signs are independent of the intracranial pressure (ICP) and the type of hydrocephalus. Surgical shunt procedures were in most cases followed by the disappearance of mental deterioration, gait disturbances, ataxia, and spasticity.
Adolescent↗
Acquired hydrocephalus. II. Diagnostic and prognostic value of quantitative isotope ventriculography (QIV), lumbar isotope cisternography (LIC), pneumoencephalography, and continuous intraventricular pressure recording (CIP).
The diagnostic and prognostic values of quantitative isotope ventriculography (QIV), lumbar isotope cisternography (LIC), pneumoencephalography (PEG), and continuous intraventricular pressure recording (CIP) were assessed on the basis of the clinical course in 160 patients suspected of having acquired hydrocephalus. The diagnostic value of a given method is defined as its reliability in the diagnosis of hydrocephalus. The reliability in the selection of hydrocephalic patients who will improve on shunt operation is designated as the prognostic value of the method concerned. As the diagnoses are based on isotopic procedures, the diagnostic values of these procedures cannot be assessed. QIV is of greater prognostic value than the other methods of examination. The presence of plateau waves in CIP is a rare, but prognostically valuable sign. The prognostic value of B waves is also good, whereas their diagnostic value is slight. Both from diagnostic and prognostic points of view, PEG is of less value is communicating hydrocephalus on account of the many false findings.
Cerebral Ventricles↗
Acquired hydrocephalus. V. Determination of the formation rate of albumin in the ventricular system.
By quantitative isotope ventriculography (QIV), the formation rate of albumin in the ventricular system (FRalb) was determined in 14 hydrocephalic and 14 nonhydrocephalic patients. The FRalb was significantly reduced in the patients with acquired hydrocephalus. By a comparison of the mean formation rate of albumin (MFRalb) and the mean absorption rate of albumin (MARalb), a significant biological difference in the two groups of patients was demonstrated.
Albumins↗
Tear flow in normal human eyes. Determination by means of radioisotope and gamma camera.
Tear flow was measured in normal human eyes by means of a radioisotope (technetium as pertechnetate in a normal saline solution), a gamma camera and a computer. By "region of interest" technique the elimination was shown to have two phases: an initial rapid elimination followed by a slower elimination after 5--7 min. The mean fractional turnover rate in the initial phase was 0.197 min.-1 (n = 35, SEM = 0.013) and in the basal phase 0.083 min.-1 (n = 35, SEM = 0.003). Assuming a constant tear volume these values corresponded to a tear flow of 1.4 microliter min.-1 and 0.6 microliter min.-1, respectively. There was no significant difference between the fractional turnover rate in the upright and supine position. No difference was found in tear flow between males and females. With the eyes closed the fractional turnover rate was low with intermittently rapid outflow of tears. Irritation to the contralateral eye with a filterpaper caused a stimulated tear flow of 4.4 microliter min.-1. A nomogram facilitating background corrections was constructed.
Eye↗
Conjunctival transport of technetium-99m pertechnetate.
Using a gamma camera coupled to a computer and a tape unit the transport of pertechnetate (Tc99m) across the conjunctiva was determined by the 'region of interest' technique in human subjects. In 11 patients with their lacrimal sacs removed a fractional turnover rate of 0.021 min-1 was found. In 21 patients with inflammed conjunctiva due to chronic dacryocystitis a fractional turnover rate of 0.027 min-1 was found, whereas the value in 11 normal individuals was 0.015 min-1. Neglecting the relatively small transcorneal route of disappearance, the values found for technetium disappearance could be regarded as representative for the transconjunctival transport of the radioisotope. This assumption was confirmed by correlating the radioactivity in the blood with the fractional turnover rate.
Adolescent↗
Combined ventilation-perfusion scintigraphy for demonstratio of pulmonary embolism.
In 34 patients with suggested pulmonary emboli, ventilation scintigraphy with 133Xe and perfusion scintigraphy with 99Tcm-labelled albumin spheres were carried out. The combined ventilation-perfusion scintigraphy had a significantly higher diagnostic specificity (1.0, confidence limit 0.69-1.0) than perfusion scintigraphy alone (0.48, 0.26-0.70). Both methods had a diagnostic sensitivity of 1.0.
Humans↗
Food stimulated lymph flow in the neck region.
Food stimulated lymph flow in the neck region was studied in 8 patients. In each patient there was a significant increase in lymph flow during eating. Changes in lymph flow occurred rapidly and it is suggested that lymph transport is an active process.
Eating↗
The effect of taste and mastication on lymph flow in the neck region.
In 10 out of 12 patients, there was a significantly stimulatory effect on lymph flow during taste and in 9 out of 10 patients there was a significant stimulatory effect on lymph flow during mastication. The stimulatory effect of mastication could be a parallel to the conditions observed in the leg but the stimulatory effect of taste could also indicate an active process perhaps of neurogenic origin.
Humans↗
[Incidence of postoperative pulmonary embolism and influence of heparin in low dosage evaluated by ventilation-perfusion scintigraphy].
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Aged↗
[Combined ventilation-perfusion scintigraphy for demonstration of pulmonary embolism].
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Humans↗
Cerebral autoregulation in unconscious patients with brain injury.
In 18 unconscious patients with traumatic brain injury, the cerebral autoregulation was tested during the first 2-3 weeks after the acute trauma. Regional cerebral blood flow (rCBF) was measured by the intra-arterial 133xenon washout method before and after an increase of about 20% in the mean arterial blood pressure (MABP) by angiotensin. The difference between MABP and intraventricular pressure (IVP) was used as cerebral perfusion pressure (PP). Simultaneously, ventricular fluid pH, lactate and pyruvate were measured. Regional loss of autoregulation indicated by a 20% flow increase was observed in 29 out of 35 studies (83%), while hemispheric loss of autoregulation was observed in only one study. The results of the autoregulation tests were unrelated to the clinical outcome, the presence of brain-stem lesion, and the ventricular fluid pH, lactate and lactate/pyruvate ratio. In repeated studies, a gradual normalization of the autoregulation was observed about 5 days after the acute trauma.
Adolescent↗
Autoregulation and CO2 responses of cerebral blood flow in patients with acute severe head injury.
Regional cerebral blood flow (rCBF), cerebral intraventricular pressure (IVP), systemic arterial blood pressure, and cerebral ventricular fluid (CSF) lactate and pH were studied repeatedly in 23 patients during the acute phase of severe brain injury lasting from 3 to 21 days after the trauma. Cerebrovascular autoregulation was tested repeatedly by means of angiotensin infusion in 21 of the patients, and CO2 response in 14 by means of passive hyperventilation. The pressure in the brain ventricles was measured continuously in all patients and kept below 45 mm Hg during the study. If the IVP increased more than 10 mm Hg during the angiotensin infusion (as in one case), the autoregulation test was considered contraindicated and the angiotensin infusion was discontinued. Dissociation between cerebrovascular autoregulation and CO2 response was a common phenomenon. Typically, autoregulation appeared preserved in the most severely injured areas of the cerebral cortex when the patient was deeply comatose, but deteriorated concomitantly with recovery; by the time the patient became alert, the autoregulation was always impaired. The CO2 response was impaired only in patients who were deeply comatose and had attacks of decerebrate rigidity; during recovery the CO2 response became normal. Thus, preserved autoregulation associated with imparied CO2 response indicated very severe brain damage, whereas impaired autoregulation associated with preserved CO2 response suggested moderate or severe brain damage in recovery. These paradoxical observations raise the question whether the preserved autoregulation seen in severely injured brain tissue is a true autoregulation caused by an active vasoconstrictor response to an increase in blood pressure.
Adolescent↗
Reproducibility of regional cerebral blood flow measurements in acute severe head injury.
In order to evaluate the reproducibility of regional cerebral blood flow (rCBF) measurements in pathological brain tissue, serial measurements were carried out in 13 determinations performed in patients who were comatose after severe head injuries within the first 2 weeks after the head trauma. The xenon-133 intra-arterial method was used for the flow measurements, and the flow was studied separately in 16 areas of the brain, producing 197 regional double determinations. The patients were maintained in a steady state during and between the measurements, and only differences of less than 2 mm Hg in the arterial CO2 pressure and less than 5 mm Hg in the perfusion pressure were tolerated. The reproducibility was found to be reasonably good as regards initial slope-flow indices and height/area flow indices and height/area flow values, whereas that of the compartmentally calculated flow parameters was poorer. On dividing the series into severely and moderately pathological areas, it could be shown that the reproducibility of the flor values in the moderately pathological brain areas was acceptable and similar to the results reported by others, whereas the reproducibility in the most severely pathological areas of the brain was rather poor, as regards the flow in the fast compartments. The correlation between the various flow parameters was found to be fairly good.
Brain Injuries↗