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F Momma

Publications and source records attributed to F Momma.

32 records · Page 2Linked to original sources
PubMed1987

The clinical significance of the P15 wave of the somatosensory evoked potential in tentorial herniation.

Somatosensory evoked potentials (SEPs) to median nerve stimulation and auditory brainstem evoked potentials (BAEPs) were recorded in 16 comatose patients who had suffered transtentorial herniation (TH) due to intracranial haematoma, hydrocephalus or tumour. An attempt was made to correlate the changes in the N14-P15 component of the central conduction time (CCT) and the I-V interpeak latencies (IPLs) of the BAEP with the clinical severity of TH. The N14-P15 component was not affected in seven patients at the diencephalic or early third-nerve stage, and six of these seven showed normal I-V IPLs. All six patients at the late third-nerve/midbrain stage or worse, however, showed abnormalities in the N14-P15 components. Interestingly, five patients showed dissociation of SEP and BAEP abnormalities suggesting a differential sensitivity of the medial and lateral lemnisci in the brainstem to ischaemia and/or compression. All five patients in whom the P15 potential was absent on either side had a poor outcome and there was a correlation between the electrical failure in the N14-P15 component and the degree of brainstem damage caused by TH as assessed clinically. Reversible loss of the P15 potential by brainstem retraction has been shown in intraoperative SEP monitoring during aneurysm surgery. Prolonged compression of the upper brainstem seems to cause irreversible loss of the P15 which should be regarded as being due to irrecoverable brainstem dysfunction.

Adolescent↗
PubMed1987

[The effect of lidocaine on brain edema and neural function].

Recently lidocaine (Ld) has been reported to have beneficial effects on neural suppression caused by experimental cerebral ischemia or spinal cord injury. In this paper, the effects of Ld on brain edema, local cerebral blood flow (lCBF), and neural function in the thalamocortical and cortical structures were experimentally studied. Vasogenic brain edema was induced by exposure of the cat's cerebral surface to the air in the manner of Prados et al. The dura mater over the left cerebral hemisphere was resected, and the brain was exposed to room air for 12 hours. The animals were divided into two groups. In the control group of 31 cats, Ld was not administered. In the treated group of 8 cats, Ld (4.5 mg/kg) was given intravenously immediately after the beginning of the air-exposure and thereafter administered as a drip infusion at the rate of 2 mg/kg/hour. In the untreated group, 12 hours after exposure, the cerebral water content measured by gravimetry in the cortex, white matter and thalamus increased by approximately 1.9, 4.1, 0.7%, respectively, compared to the control values. Local CBF measured by the hydrogen clearance method decreased to about 71, 57 and 56% of the control value, respectively. The latency of the N1 component of the somatosensory evoked response (SER) was prolonged significantly 6 hours after air-exposure. The amplitude of the direct cortical response (DCR) decreased significantly 6 hours after air-exposure, and became approximately 50% of the control 12 hours after exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Interaction between neurogenic and metabolic factors upon deterioration in cerebrovascular tonus--experimental study on the etiology of cerebral vasoparesis].

It is widely accepted that a tremendous increase in cerebral blood volume (CBV) due to progressive cerebral vasoparesis is an essential to the development of acute brain swelling. This study was designed to determine whether neurogenic and/or metabolic factors are predominant and how these interact with each other in producing cerebral vasoparesis. Fifty-one awake cats immobilized with pancuronium bromide were divided into 4 groups: group I, control; group II, normocapnic hypoxia (PaO2 = 50 mmHg); group III, normoxic hypercapnia (Pa-CO2 = 70 mmHg), and group IV, increased intracranial pressure (ICP = 40 mmHg) by brain compression. Systemic arterial pressure (BP), CBV (photoelectric method), and ICP (epidural pressure) were continuously recorded. The dorsomedial hypothalamic nucleus (DM) and the reticular formation of the midbrain (MB-RF) were bilaterally coagulated by a stereotaxic technique (3mA, 1 min). Therefore alterations in cerebrovascular tonus created by destruction of the cerebral vasomotor centers were examined in the animals with metabolically induced cerebral vasodilatation to various degree's. In group I, vasomotor center destruction resulted in an immediate and transient decrease in BP (DM; -14.1 +/- 6.7 mmHg, MB-RF; -10.2 +/- 4.8 mmHg) and simultaneous increase in CBV and ICP (DM; 7.6 +/- 7.0 mmHg, MB-RF; 6.0 +/- 5.6 mmHg) for 3 to 4 minutes. Increase in ICP by destruction of vasomotor centers reduced significantly in group II (DM; 2.3 +/- 2.6 mmHg, MB-RF; 1.6 +/- 1.2 mmHg) and reduced slightly in group IV (DM; 7.5 +/- 4.0 mmHg, MB-RF; 4.8 +/- 3.2 mmHg). In these 3 groups, autoregulation of cerebral blood flow and CO2 vasoreactivity were not changed by destruction of vasomotor centers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effects of methylprednisolone on cortical neural activity, blood flow, and water content in air exposure-induced cerebral edema.

The correlation of changes in cortical neuron activity with water content and local cerebral blood flow was investigated in cats with brain edema produced by air exposure. The further effect of high-dose methylprednisolone on these factors was studied. Six hours after exposure of the brain surface to air, the water content of the white matter significantly increased. The local blood flow of the cortex and white matter significantly decreased with significant suppression of cortical neural activity (direct cortical response), indicating that ischemia was responsible for neural suppression. A single, large dose of methylprednisolone (30 mg/kg, i.v.) at the beginning of air exposure significantly reduced brain edema of the cortex and white matter 12 h after air exposure and improved the local blood flow of the cortex. Methylprednisolone also caused a remarkable improvement in cortical neural activity. This steroid effect on cortical neural function may play a role in the rapid neurologic improvement observed with their use in addition to the effect on brain edema.

Air↗
PubMed1986

Intracranial aneurysm due to metastatic choriocarcinoma.

The case of a woman with an episode of subarachnoid hemorrhage 2 days after delivery is presented. An emergency operation was performed, and an intracerebral clot from a ruptured aneurysm was removed. Histologic examination of the resected aneurysm showed metastasis from a choriocarcinoma to the aneurysmal wall. Six cases of intracranial aneurysm due to metastasis of choriocarcinoma are reviewed.

Adult↗
PubMed1986

[The role of brain-stem vasomotor centers on the neurogenic control of cerebrovascular tonus. Part 2: The effect of stimulation of the medullary reticular formation on cerebrovascular tonus].

Acute brain swelling has been proposed to be caused by vasomotor paralysis secondary to disruption of metabolic and/or neurogenic control of cerebrovascular tone. In previous experiments, acute brain swelling was produced by stimulation of the reticular formation of the medulla oblongata (MORF) with destruction of the dorsomedial nucleus of the hypothalamus (DM) and the reticular formation of the midbrain (MBRF) in 2 (out of 56) animals. The purpose of the present study is to clarify the effect of stimulation of the MORF on cerebrovascular tone. Using 32 cats, blood pressure (BP), intracranial pressure (ICP) and cerebral blood volume (CBV) were continuously measured. The animals were divided into 4 groups: those in which the ICP was normal (Group A), those in which the ICP increased after subarachnoid hemorrhage (Group B), those which underwent superior cervical ganglionectomy (Group C) and those in which the spinal cord was transected at the C2 level (Group D). In all animals, the MORF was stimulated after the DM and MBRF were destroyed. Thirty minutes after cessation of stimulation, the BP was increased again by injection of angiotensin II until it reached the same level as with MORF stimulation. The vasomotor index (VI), defined by delta ICP/delta BP, was calculated and compared between the two situations. BP, ICP and CBV increased simultaneously immediately after MORF stimulation. In 29 out of the 32 animals, ICP increased abruptly from 2 to 48 mmHg and after ten seconds or more decreased gradually. The BP rose about 50 mmHg more slowly than the ICP. After cessation of MORF stimulation, BP, ICP and CBV returned to the control value.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1986

[The effect of brain-stem vasomotor centers on the neurogenic control of cerebrovascular tonus--Part 3. The effects of destruction and stimulation of the brain-stem on intracranial pressure in acute subarachnoid hemorrhage].

The purpose of the present study is to clarify the effects of destruction and stimulation of the brain-stem on intracranial pressure (ICP) in experimentally induced subarachnoid hemorrhage (SAH). Using 23 cats, blood pressure (BP), ICP and local cerebral blood volume (CBV) were continuously measured. Acute SAH was produced by injection of autogenous blood (3 to 7 ml) into the cisterna magna. The animals were divided into two groups. Group A: those in which hypothalamic dorsomedial nucleus (DM) and reticular formation of the midbrain (MBRF) were coagulated bilaterally one hour after SAH and Group B: in addition to the procedure of Group A, reticular formation of the medulla oblongata (MORF) was electrically stimulated bilaterally. In 19 out of 23 cats of both groups, transient small increases in ICP and CBV were observed during coagulation and/or stimulation of DM, MBRF and MORF respectively in the animals whose ICP remained approximately 20 mmHg or below and progressive increase in ICP was never evoked. In 3 animals of Group A whose ICPs remained high at more than 20 mmHg, sequential destruction of DM and MBRF induced stepwise increase in ICP to 40 to 80 mmHg and consequently resulted in acute brain swelling. In 1 animal of Group B whose ICP fluctuated around 20 to 40 mmHg, biphasic increase in ICP to 100 mmHg was repeatedly evoked by stimulation of MORF. It is concluded that in the condition of increased ICP produced by SAH, lesions in the DM and MBRF and stimulating condition of MBRF may result in acute brain swelling.

Acute Disease↗
PubMed1984

Acute intracranial hypertension and brain-stem blood flow. An experimental study.

This study has been carried out to evaluate the effect of supratentorial mass lesions on the local cerebral blood flow (CBF) of the brain stem. Local CBF of the thalamus, inferior colliculus, and medulla oblongata, and supra- and infratentorial pressure were serially measured in 52 cats with intracranial hypertension produced by supratentorial balloon expansion. The mean control local CBF's in the thalamus, inferior colliculus, and medulla oblongata were 37.5, 42.1, and 30.7 ml/100 gm/min, respectively. At 20 to 30 mm Hg of supratentorial pressure, the local CBF of the thalamus started to decrease, and at 20 mm Hg of infratentorial pressure, the local CBF of the inferior colliculus began to decrease. Finally, at 40 to 60 mm Hg of infratentorial pressure, the local CBF of the medulla oblongata was affected. At the beginning of uncal herniation, indicated by anisocoria, the mean local CBF of the inferior colliculus abruptly decreased from 33.7 to 19.6 ml/100 gm/min in 16 cats. The Cushing response was evoked at a mean supratentorial pressure of 93.4 mm Hg and infratentorial pressure of 49.9 mm Hg in 16 cats. When the systemic arterial pressure was increased to the highest level in 13 cats, the mean local CBF of the medulla oblongata did not show significant change (a decrease from 22.8 to 20.9 ml/100 gm/min). The results suggest that at the beginning of uncal herniation, the local CBF of the upper brain stem markedly decreased. During the Cushing response, the local CBF of the medulla oblongata did not change significantly.

Acute Disease↗
PubMed1984

[The role of brain-stem vasomotor centers on the neurogenic control of the neurogenic control of cerebrovascular tonus. Part 1: In special reference to cerebral blood volume and intracranial pressure].

An increase in cerebral blood volume (CBV) due to a decrease in cerebrovascular tonus has been though to be a major factor in the cause of acute brain swelling. It has been reported that the dorsomedial nucleus of the hypothalamus (DM), one of the brain-stem vasomotor centers, regulates cerebrovascular tonus. The DM and other vasomotor centers, such as the midbrain reticular formation (MBRF) and the reticular formation of the medulla oblongata (MORF), are connected through a series of nerve fibers. This experiment was designed to clarify the neurogenic control of the DM, MBRF, and MORF on cerebrovascular tonus. Using fifty-six cats, unilateral and bilateral DM(A 1.2, L2.0, H-10.0), MBRF (A4.0, L4.0, H0), and MORF (P10.0, L2.5, H-9.0) were coagulated stereotaxically with the condition of 15-10 mA for 1 minute. The lesions in the DM and MBRF were enlarged by increasing the current intensity of electrical coagulation. The effects of the increase on a number of simultaneously coagulated lesions were examined. Changes in systemic blood pressure (BP), intracranial pressure (ICP), and CBV were continuously recorded. Temporary increases in ICP (mean increase 16 mmHg, n = 14) and CBV were observed after unilateral coagulation of the DM. These increases were associated with transient systemic hypotension. The changes lasted only for approximately 5 minutes. The changes that occurred in ICP and CBV as a result of unilateral coagulation in the MBRF were almost the same as those that occurred after coagulation of the DM. In the latter case, the duration of the change was approximately 6 minutes with a mean increase of 12 mmHg (n=12).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

[Spontaneously cured carotid-cavernous fistula verified by angiography--report of a case (author's transl)].

A case of spontaneously cured carotid-cavernous fistula has been reported in details with a review of literatures. Seven cases verified by angiography have been described so far in the literature. Spontaneous cure has been revealed within 6 months after the initial examination in 5 out of 7 cases by follow up angiography, and has occurred in five women of middle age. The presented case was a 45 year-old female who has suffered from the exophthalmos associated with disturbed eye movements of two months duration. On January 2, 1977, the carotid angiography demonstrated a c--c fistula and an oval aneurysm of the middle cerebral artery on the right side. The exopthalmos was slowly decreased with the conservative treatment after two months. The c--c fistula was not demonstrated by the angiography carried out on March 10, 1977, and was not revealed thereafter by follow up studies.

Arteriovenous Fistula↗
PubMedDate not supplied

The effect of experimental ischaemia on the direct cortical response of the motor cortex in primates.

We studied the changes in amplitude of the first short latency positive potential (2.3 +/- 0.3 msec, mean +/- S.D.) of the direct cortical response (DCR) elicited by surface electrical stimulation of the motor cortex in anaesthetised baboons. Local cortical blood flow, measured by the hydrogen clearance method, was progressively reduced by acute middle cerebral artery occlusion and subsequent hypotension and was related to the amplitude of this potential. With flow levels greater than 25 ml/100 g/min the DCR was essentially unaffected, but it was lost with flows below 20 ml/100 g/min. These results indicate a threshold relationship between the generation of the electrical activity evoked in the cortical elements and local cortical flow, similar to that previously demonstrated for cortical somatosensory evoked potentials.

Animals↗