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D P Becker

Publications and source records attributed to D P Becker.

234 records · Page 13Linked to original sources
PubMedDate not supplied

MR imaging findings after transplant surgery for Parkinson disease.

The authors describe the magnetic resonance (MR) imaging appearance of the head of the right caudate nucleus in patients who have undergone adrenal medullary transplant surgery for Parkinson disease. All four patients examined showed some clinical improvement after surgery. The MR images acquired 4-6 months postoperatively showed no evidence of caudate atrophy. Three of the four patients showed some increase in size of the operated caudate head relative to preoperative studies. Neither cavitation nor high signal intensity on T2-weighted images was evident within the caudate head. The one patient studied after administration of gadopentetate dimeglumine showed no abnormal enhancement. These images provided a description of the transplant site and also suggested that the clinical improvement seen was not due to simple ablation of caudate tissue or to postoperative inflammation. The increase in size of the caudate head also suggested that some implanted tissue may have remained in these patients at the time the MR images were acquired.

Adrenal Medulla↗
PubMedDate not supplied

Cerebral blood flow is regulated by changes in blood pressure and in blood viscosity alike.

There is still considerable controversy regarding the influence of blood viscosity upon CBF. We have measured CBF with microspheres in 23 cats. Autoregulation was disturbed in the left caudate nucleus by microsurgical occlusion of the left middle cerebral artery. Induced hypertension or hypotension was used and i.v. mannitol (1 g/kg) administered. In all cats blood viscosity decreased an average of 16% at 15 minutes and, in 16 cats, increased 10% at 75 minutes post-mannitol. CBF in the right caudate was 79 +/- 6 ml/100g/min, in the left 38 +/- 6 (p less than 0.001). Only minor changes of CBF occurred in areas with presumed normal autoregulation, including the right caudate, in conjunction with pressure or viscosity changes. In the left caudate CBF decreased 21% with hypotension and 18% with higher viscosity, more than on the right (p less than 0.01 and p less than 0.2, respectively). CBF increased in the left caudate 56% with hypertension and 47% with lower viscosity, again much more than on the right (p less than 0.001 and p less than 0.01, respectively). In the other area which is (nearly) exclusively supplied by the middle cerebral artery of the cat, i.e., the ectosylvian cortex, results were similar to those in the caudate nucleus. These results show that viscosity changes must result in compensatory readjustments of vessel diameter, but that these adjustments do not occur where autoregulation to pressure changes is known to be defective. The adjustments to viscosity changes might be called blood viscosity autoregulation of CBF. We hypothesize that pressure autoregulation and blood viscosity autoregulation share the same mechanism.

Animals↗
PubMedDate not supplied

Methylprednisolone treatment in patients with brain tumors.

A study was made in 10 patients with brain tumors of the effect of methylprednisolone sodium succinate (Solu-Medrol) on clinical neurological status, intracranial pressure, and periventricular elastance. Significant clinical improvement and reduction in periventricular elastance both ocurred within 24 hours of starting treatment, whereas intracranaial pressure was not significantly reduced until the 2nd day of therapy.

Adenoma, Chromophobe↗
PubMedDate not supplied

Significance of bilateral abnormalities on the CT scan in patients with severe head injury.

One hundred forty head injured patients, managed by a standardized protocol of early diagnosis, surgical decompression, and intensive therapy, had computerized tomographic (CT) scans within 1 hour or arrival in the emergency room. Ninety of these patients had serial scans during the subsequent week. On admission, 26 patients had normal scans, 75 had unilateral lesions, and 39 had bilateral lesions. Thirteen who had unilateral lesions on admission developed contralateral lesions during the first week for a total of 52 patients with bilateral lesions. These 52 patients could be separated into two distinct groups: (a) those with small ventricles and no change or a slight, homogeneous decrease in density of the brain parenchyma, who had better neurological status on admission, lower intracranial pressure (ICP), and better outcome; and (b) those with bilateral increased density lesions, who had poorer motor response on admission, higher ICP, and worse outcome. The value of CT scanning in management, prognosis, and outcome is emphasized.

Adolescent↗
PubMedDate not supplied

A new model of concussive brain injury in the cat produced by extradural fluid volume loading: I. Biomechanical properties.

This study presents a new device for producing experimental, concussive head injury together with a detailed description of biomechanical features of fluid percussion brain injury in the cat. Anaesthetized cats were subjected to multiple (N = 3) or single injuries (N = 87). The variables studied in repeated injury experiments included the volume of fluid injected intracranially, rate of fluid flow, and the associated pressure transients recorded extracranially in the injury device and intracranially at supratentorial and infratentorial sites. Peak fluid flow increased with increasing volumes of fluid loaded intracranially. Extracranial pressure peaks and durations increased when volume loading was increased. Extracranial and intracranial pressure transients were similar at all recording sites. The form of pressure transients recorded in single injury experiments was similar to that recorded in multiple injury experiments. In single injury experiments, the extracranial pressure peaks and durations also increased with increased intracranial fluid volume loading. The slopes describing the relationships between intracranial volume loading and extracranial pressure transients were significantly different in single and multiple injury experiments. Details of the design and use of the head injury device are also discussed.

Animals↗
PubMedDate not supplied

A new model of concussive brain injury in the cat produced by extradural fluid volume loading: II. Physiological and neuropathological observations.

This study examined physiological and histopathological changes in the cat produced by a new experimental fluid injury device. Spontaneously breathing (N = 14) and artificially ventilated (N = 45) cats were subjected to systemically varied magnitudes of fluid percussion brain injury. Within certain injury ranges, increasing magnitudes of fluid percussion injury produced increasing durations of apnea, as well as greater transient increases in mean arterial blood pressure, intracranial pressure and cerebral perfusion pressure. Acute increases in intracranial pressure may have been related to cerebral vasodilatation produced by the systemic hypertension following brain injury. Injuries associated with pressure transients greater than 10 atm ms produced concussive responses, including irreversible apnea in spontaneously breathing cats and temporary pupillary dilatation, increases in heart rate and mean arterial blood pressure in artificially ventilated cats. Injuries greater than 39 atm ms frequently produced histopathological and physiological indices of significant irreversible brain damage, including fixed and dilated pupils, systemic cardiovascular hypotension and deteriorating blood gases. Injury magnitudes less than 20 atm ms did not produce macroscopic evidence of histopathology, intermediate injury ranges produced increasing evidence of subarachnoid and petechial hemorrhage while injury levels greater than 40 atm ms frequently produced significant histopathology including massive hematomas. Injury greater than 10 atm ms resulted in opening of the blood-brain barrier, as assessed by extravasation of horseradish peroxidase. Injury greater than 19 atm ms produced suppression of EEG amplitudes which did not recover for up to 40 minutes after injury. These data provide detailed information on the physiological and histopathological consequences of fluid percussion injury in the cat and indicate that this modified fluid percussion apparatus can produce graded levels of brain injury similar to those previously reported for fluid percussion injury.

Animals↗
PubMedDate not supplied

Simultaneous, quantitative measurement of local blood flow and glucose utilization in tissue samples in normal and injured feline brain.

Cerebral blood flow (CBF) and local cerebral glucose utilization (LCGU) were measured using radioactive microspheres and [14C]2-deoxyglucose, respectively, in 26 brain regions in control animals (n = 8) and in animals (n = 4) sustaining low-level experimental brain injury. Examination of the initial (resting) CBF measurement in the uninjured cats revealed two subgroups with significantly (p less than 0.01) different CBF levels. In uninjured cats with normal CBF levels (33.4 +/- 1.8 ml/100 g/min) there was a close linear relationship between CBF and LCGU (n = 0.71, p less than 0.01). In contrast, the remainder of the uninjured cats exhibited abnormally high levels of CBF (72.6 +/- 9.9 ml/100 g/min) and the absence of a close relationship between CBF and LCGU (r = 0.27). One hour following low-level (2.0 atm) fluid percussion brain injury, CBF was increased and LCGU was decreased, though not significantly. The relationship between CBF and LCGU remained intact (r = 0.66, p less than 0.01) in most brain regions. However, the relationship between CBF and LCGU in the hippocampus differed significantly from the relationship between the two parameters in the rest of the brain. Thus, the use of the radioactive microsphere method for CBF measurements allows multiple measurements of CBF and permits the assessment of the status of the cerebral vasculature prior to experimental manipulations such as traumatic brain injury. In view of our current findings of an abnormal relationship between CBF and LCGU in cats with high resting CBF levels, this is an important advantage. In addition, the combination of the microsphere and 2-DG techniques within the same tissue samples allows for the investigation of the effects of traumatic injury on the important relationship between CBF and LCGU.

Animals↗