Biomedical subjects

K Elisevich

Publications and source records attributed to K Elisevich.

At least 19 recordsLinked to original sources

PubMed2000

Transient hemifacial sensory loss with xerophthalmia following temporal lobectomy.

OBJECTIVE AND IMPORTANCE: The occurrence of a unilateral sensory loss in the second trigeminal distribution and the inability to tear following an ipsilateral temporal lobectomy has not been noted despite a number of reports of cranial nerve compromise under similar situations. CLINICAL PRESENTATION: A 48-year-old woman experienced complex partial seizures over three years attributable to the presence of cavernous malformations of the right temporal lobe. INTERVENTION: An anterior temporal extrahippocampal resection was performed. The surgery was marked by the need for electrocoagulation of the dural base of the temporal lobe where numerous bleeding points were encountered. Postoperatively, the patient experienced an ipsilateral maxillary division sensory loss, absence of tearing, and diminished nasal congestion for an eight-month period until resolution. CONCLUSION: Injury of the fibers of the maxillary division of the trigeminal nerve and the adjacent greater superficial petrosal nerve appears to be the cause. No prior account of such an occurrence has been published.

Electrocoagulation↗

PubMed2000

Ictal spiking patterns recorded from temporal depth electrodes predict good outcome after anterior temporal lobectomy.

PURPOSE: Investigators have shown that the presence of ictal spiking (IS) recorded from temporal depth electrodes is associated with mesial temporal sclerosis (MTS). We investigated the relation of IS to seizure control and pathology after anterior temporal lobectomy (ATL). METHODS: All patients undergoing intracranial ictal monitoring from a single institution since 1989 were identified. Those who did not undergo ATL or had postoperative follow-up of <1 year were excluded. All received at a minimum bilateral temporal depth electrodes. Ictal recordings were reviewed for the presence of IS, and the proportion of seizures with IS was determined for each patient. Outcome was determined by using Engel's classification. Surgical specimens were reviewed for pathology. Statistics used were chi2, Fisher exact test, and Wilcoxon rank sum. RESULTS: Forty patients with 571 seizures were reviewed. In 292 seizures from 32 patients, IS was seen. Outcomes were 24 class I (22 with IS), five class II (four with IS), three class III (one with IS), seven class IV (four with IS), and one lost to follow-up (with IS). Pathologic review revealed 25 with MTS, 22 of whom had IS. The presence of IS was associated with class I outcomes (p = 0.04), but not MTS (p = 0.06). Patients with class I outcomes had a significantly greater proportion of seizures with IS (mean, 0.58 +/- 0.3) compared with other outcomes (mean, 0.30 +/- 0.3, p = 0.02). CONCLUSIONS: The presence of IS and higher proportion of seizures with IS correlated with good seizure outcome after ATL. This information may be used in preoperative counseling.

Electrodes, Implanted↗

PubMed2000

Effects of vagus nerve stimulation on progressive myoclonus epilepsy of Unverricht-Lundborg type.

PURPOSE: A 34-year-old woman with progressive myoclonus epilepsy of Unverricht-Lundborg type was considered for vagus nerve stimulation (VNS) therapy. METHODS: After demonstration of intractability to multiple antiepileptic regimens and progressive deterioration in cerebellar function, the patient was implanted with a vagus nerve stimulator and followed for 1 year. Neurological status, seizure frequency, and parameter changes were analyzed. RESULTS: VNS therapy resulted in reduction of seizures (more than 90%) and a significant improvement in cerebellar function demonstrated on neurological examination. The patient reported improved quality of life based in part on her ability to perform activities of daily living. CONCLUSIONS: VNS therapy may be considered a treatment option for progressive myoclonus epilepsy. The effects of VNS on seizure control and cerebellar dysfunction may provide clues to the underlying mechanism(s) of action.

Adult↗

PubMed1999

Developing an effective program to complete ictal SPECT in the epilepsy monitoring unit.

With the availability of more stable radiopharmaceuticals, the ictal single photon emission computed tomography (SPECT) perfusion study has emerged as a useful noninvasive functional neuroimaging tool in the presurgical evaluation of patients with medically intractable partial epilepsy. The purpose of this study was to determine whether the development of a program using trained electroencephalography (EEG) technologists to perform ictal injections in the epilepsy monitoring unit enabled a more efficient delivery of radiopharmaceuticals and therefore a higher specificity and sensitivity of outcome. All patients admitted to the epilepsy monitoring unit for prolonged video/EEG monitoring as part of the presurgical evaluation were eligible for completion of an ictal SPECT study using a three-way needle-free apparatus. Over a 19-month period, 85 (77%)) of 110 eligible patients were successfully injected during typical partial seizures. Various factors were analyzed including latency of ictal injection (27.3+/-20.8 [S.D.] s), radiopharmaceutical wastage (40% dose utilization), radiation safety parameters (1.6% contamination rate), and preliminary data of localizing value. Our results show that ictal SPECT can be a safe, noninvasive procedure completed on a routine basis in the epilepsy monitoring unit when appropriately trained support staff are utilized as part of a structured multidisciplinary program.

Adult↗

PubMed1999

Morbidity and infection in combined subdural grid and strip electrode investigation for intractable epilepsy.

The coverage of large surface areas of the brain for electrographic monitoring purposes necessitates a craniotomy to achieve comprehensive sampling. We undertook a review and prospective analysis over 3 years of 38 patients undergoing craniotomy for electrode implantation. The indication for invasive monitoring was to determine candidacy for resective surgery in patients whose seizure focus was not well localized by scalp electroencephalography and other noninvasive testing. Prophylactic cultures from the epidural space were obtained at electrode removal. There were five positive epidural cultures. All five patients went on to seizure-free status. Two positive cultures occurred in patients without obvious infection and who were not treated with antibiotics. Other complications included individual cases of atrial fibrillation, pulmonary edema, postoperative fever, and epidural hematoma. There was no mortality or permanent neurologic morbidity related to craniotomy for electrode placement. There was a 7.9% rate of clinical infection per patient and a 5.7% rate per craniotomy side. This study has identified several factors that significantly correlate with positive epidural culture results: > 100 electrodes, more than ten cables, more than 14 days of implantation, and more than one cable exit site.

Adolescent↗

PubMed1999

Test-retest stability and short-term habituation of the N1 and gamma band response.

The gamma band response (GBR) is an exogenous, cortically generated, event-related potential that occurs between 20- and 170-msec post-stimulus onset. The auditory GBR is superimposed on the transient evoked middle and long latency cortical auditory evoked potentials and demonstrates a peak spectral frequency between 30 and 40 Hz. The present investigations were conducted to evaluate the test-retest stability and short-term habituation of the GBR. Both the GBR and N1 were recorded from six normal-hearing, neurologically intact subjects (Investigation 1, test-retest stability) and two subjects with intractable epilepsy with implanted subdural electrode grid arrays (Investigation 2, short-term habituation characteristics). For Investigation 1, the test-retest interval was 1 month. For Investigation 2, 300 samples were acquired per stimulus block (a 10-minute interval) and then subaveraged in blocks of 25 to 50 samples each. Results suggest that (1) like N1, the GBR shows high repeatability (qualitative) and test-retest stability (quantitative) and (2) the GBR does not demonstrate evidence of short-term habituation.

Adult↗

PubMed1998

SPARC: a signal of astrocytic neoplastic transformation and reactive response in human primary and xenograft gliomas.

In an attempt to identify genetic alterations occurring early in astrocytoma progression, we performed subtractive hybridization between astrocytoma and glioblastoma cDNA libraries. We identified secreted protein acidic and rich in cysteine (SPARC), a protein implicated in cell-matrix interactions, as a gene overexpressed early in progression. Northern blot and immunohistochemical analyses indicated that transcript and protein were both elevated in all tumor specimens (grades II-IV) examined when compared with levels in normal brain. The level of SPARC expression was found to be tumor-dependent rather than grade-related. Immunohistochemically, SPARC protein was found to be overexpressed in 1) cells in the less cellularly dense regions within the tumor mass, 2) histomorphologically neoplastic-looking cells in adjacent normal brain at the tumor/brain interface, 3) neovessel endothelial cells in both the tumor and adjacent normal brain, and 4) reactive astrocytes in normal brain adjacent to tumor. Using a combination of DNA in situ hybridization and protein immunohistochemical analyses of the human/rat xenograft, SPARC expression was observed in the human glioma cells within the tumor mass, and in cells that invaded along vascular basement membranes and individually into the rat brain parenchyma, suggesting it may be an invasion-related gene. While it remains to be determined whether SPARC functionally contributes to tumor cell invasion, these data suggest that the early onset of increased SPARC expression, though complex, may serve as a signal indicative of neoplastic astrocytic transformation and reactive response to tumor-induced stress.

Animals↗

PubMed1998

Surgical treatment of intractable epilepsy attributable to multiple sclerosis.

Surgically removing a focus of epileptogenicity attributable to a multiple sclerosis (MS) plaque has not previously been considered a treatment option. Medically intractable partial epilepsy due to a chronically situated MS plaque is uncommon because most cases are self-limiting or managed with antiepileptic medication. We report a case of partial epilepsy resulting from such a plaque situated at the gray-white interface in the anterior parahippocampal gyrus. A favorable outcome was achieved by resection of the epileptogenic area.

Adult↗

PubMed1997

Hippocampal connexin 43 expression in human complex partial seizure disorder.

An increase in the cellular production of gap junction proteins and increased numbers of gap junctions in the neuronoglial syncytium of an epileptic focus have been proposed as a possible mechanism underlying synchronization of discharge. To study this issue, both Northern and Western blot analyses of the gap junction protein connexin 43 mRNA and protein abundance were performed on hippocampal tissue resected from patients presenting with a complex partial seizure disorder arising from the medial temporal area and the hippocampus in particular. Samples from 15 patients with medically intractable seizures were compared to those from 5 nonepileptic patients requiring temporal lobectomy in life-threatening situations. Six of the 15 epileptic patients underwent noninvasive electrographic recording, whereas the remaining 9 patients required intracerebral electrodes for extraoperative recording and therefore showed a more discrete focality than the noninvasive recordings. A decline in the mean levels of connexin 43 mRNA expressed predominantly in astrocytes was noted in the epileptic patient groups, particularly for those cases requiring intracranial electrode placement where ictal onset was more clearly established to be intrahippocampal. Quantitation of connexin 43 protein in both epileptogenic and nonepileptogenic hippocampal tissues showed no significant differences in expression. Although mean values for mRNA showed a decline, clinical outcomes postoperatively showed no correlation with either mRNA or protein expression individually in our epileptic population. The findings indicate that there is effectively no upregulation of mRNA and no increased production of connexin 43 protein in response to the development of epileptogenicity. Rather it appears the influence of gap junctions as a substrate of epileptogenicity in any mechanism(s) underlying synchrony or electrical propagation may be a function of the dynamic state (open versus closed) of the membrane-bound gap junction.

Adult↗

PubMed1996

Hodgkin's disease of the orbit with intracranial extension.

A rare presentation of intraorbital Hodgkin's lymphoma in a patient without prior history of systemic disease who complained of episodic monocular visual loss with minimal proptosis is reviewed. The case is further distinguished by intracranial extension of the tumor. A literature review highlights such an unusual event against the background of prior experience. Despite the fact Hodgkin's disease accounts for about 30% of systemic lymphomas, it rarely occurs in the orbit, where non-Hodgkin's lymphomas account for practically all lymphomas studied. Hodgkin's disease has occurred in patients with known systemic disease in its terminal stages and usually with proptosis as the presenting symptom. We present the case of a young man with intraorbital Hodgkin's disease whose presenting symptom was recurrent transient episodes of complete monocular visual loss. His condition was further distinguished by seeding of the skull base and dura by tumor.

Adult↗

PubMed1995

Size estimation and magnification error in radiographic imaging: implications for classification of arteriovenous malformations.

PURPOSE: To assess magnification error in digital subtraction angiography as it pertains to arteriovenous malformation (AVM) size. METHODS: A rectangular grid phantom with equally spaced markers mounted in a stereotactic frame was imaged with digital angiographic equipment. The location and orientation of the grid was altered relative to the central plane of the phantom. Both linear and area measurements were made according to the perceived location of phantom markers using a standard catheter calibration technique and compared with stereotactically derived estimates. Finally, a single case example of an angiographically imaged rolandic AVM was used to compare linear dimensions obtained with both described techniques. RESULTS: The determination of location and size with standard angiographic imaging is subject to error because of the divergent geometry of the incident x-ray beam. The resulting nonconstant geometric magnification causes errors in linear measurements of 10% to 13% at depths of 7 cm from the calibration plane. Errors in area measurements at the same position increase by 20% to 25%. Measurements of maximum diameter or cross-sectional area may have an additional error when nonspherical objects are inclined to the viewing direction (40% at 45 degrees inclination). These errors are reduced to less than 1 mm using the stereotactic technique. Some commercial angiographic systems have internal software to enable a spatial calibration based on known distances in the image or on the diameter of a catheter. The catheter technique was accurate in the calibration direction (perpendicular to the catheter axis) but had a 12% error in the direction parallel to the catheter because of a nonunity aspect ratio in the video system. Measurement of the dimensions of a rolandic AVM using the catheter calibration technique had an error that ranged from -3% to +26% (standard error, 20%) with respect to the stereotactic technique. CONCLUSIONS: Numerous nonstereotactic referential systems for determining linear distances are inherently erroneous by varying degrees compared with the stereotactic technique. Area and volume determinations naturally increase this error further. To the extent that no standardized method for determining linear distances exists, significant variations in estimation of AVM size result. Classification schemes for AVMs have been hampered by this technical error.

Algorithms↗

PubMed1994

Parvalbumin-containing GABAergic neurons in the basal ganglia output system of the rat.

The output of the basal ganglia is directed through the entopeduncular nucleus (EPN) and the substantia nigra pars reticulata (SNR) and pars lateralis (SNL), which provide a gamma-aminobutyric acidergic (GABAergic) projection to various nuclei of the thalamus and brainstem. Although many neurons within the SNR and EPN have been described as modality specific, the morphological and neurochemical similarities preclude their precise identification. In the present study, the immunocytochemical localization of parvalbumin, a calcium-binding protein, is used in combination with axonal tracing to verify neuronal heterogeneity within the SNR, SNL, and EPN. The results reveal that the majority of neurons in all three centers contain parvalbumin. The parvalbumin-containing neurons are distributed in the caudal two-thirds of the EPN, the rostral part of the SNL, and the lateral two-thirds of the entire rostrocaudal extent of the SNR, the areas involved in sensorimotor function of the basal ganglia. Moreover, the nigrothalamic, nigrocollicular, and EPN-thalamic neurons possess parvalbumin immunoreactivity, whereas the EPN-habenular neurons are devoid of parvalbumin immunoreactivity. The results indicate a neurochemical heterogeneity within the GABAergic output neurons of the basal ganglia and suggest that the parvalbumin-containing neurons of the SNR, SNL, and EPN are the tonically active output neurons that form a major link in the disinhibitory neuronal circuit of the basal ganglia, especially that concerned with sensorimotor function.

Animals↗

PubMed1994

Neurochemical compartmentalization of the globus pallidus in the rat: an immunocytochemical study of calcium-binding proteins.

The globus pallidus external segment forms a major target center of the mammalian striatum which is characterized by neurochemically distinct compartments. The present study was undertaken to determine if a corresponding compartmentalization exists within the globus pallidus external segment in the rat. Immunocytochemical examination of the calcium-binding proteins parvalbumin and calbindin D28kDa, which are present in neurons of the striatal matrix compartment, was employed. The results indicate three neurochemically distinct compartments within the globus pallidus external segment: 1) an area in the medial aspect of the entire length of the globus pallidus that contains dense immunoreactivity for calbindin D28kDa; 2) a narrow rim at the striatopallidal junction in the rostral two-thirds of the globus palidus that contains calbindin D28kDa immunoreactivity designated as the "border zone" of the globus pallidus; and 3) an area between these two zones showing very poor immunoreactivity for calbindin D28kDa but containing parvalbumin immunoreactive neurons. The calbindin D28kDa immunoreactive border zone corresponds to the area of the globus pallidus where striatal inputs converge extensively, whereas the rest of the nucleus is involved in segregated, topographically organized pathways. Parvalbumin-containing neurons are involved in the propagation of striatal output related to striosomal and sensorimotor aspects of basal ganglia function. The present results also indicate that calbindin D28kDa immunoreactivity is completely absent from striosomal neurons and is therefore a useful marker for striatal compartments.

Animals↗

PubMed1994

The pallidostriatal projection in the rat: a recurrent inhibitory loop?

The pallidostriatal projection in the rat was investigated employing the PHA-L tracing technique. Following inotophoretic injections into the lateral aspect of the globus pallidus external segment, the ipsilateral striatum showed patches of dense anterograde labeling separated by areas containing sparse anterograde labeling and isolated retrogradely labeled neurons. The densely labeled patches did not correspond to any known compartments of the striatum. The retrogradely labeled neurons consistently showed similar distribution and morphological features reminiscent of striatal type II projection neurons. As all projection neurons of the striatum and all pallidal neurons are GABAergic, the complementary pattern of anterogradely and retrogradely labeled profiles from the globus pallidus suggest a possible mechanism whereby a horizontal inhibition may be exerted on groups of striatal neurons via the striato-pallido-striatal pathway.

Animals↗

PubMed1994

A table-mounted stereotactic system for digital angiography: a means of standardizing arteriovenous malformation measurement.

A detachable noninvasive table-mounted stereotactic device is described for use with digital radiography. The device is designed for standard two-view orthogonal projections but may be adjusted to allow for projections angled from the axial plane. When applied to the imaging of arteriovenous malformations (AVMs), it negates the influence of a variety of geometric and mechanical factors which would otherwise interfere with the determination of size. An accurate appreciation of AVM size, in turn, would allow a more reliable means of categorization of AVMs into distinctive groups for classification purposes and prognostication.

Algorithms↗

PubMed1994

Neuropathology of intracranial arteriovenous malformations following conventional radiation therapy.

Conventional fractionated radiation therapy was used in 15 patients to treat arteriovenous malformations (AVMs) of the brain deemed inoperable or incompletely obliterated using endovascular or surgical techniques. The AVMs measured from 0.8 to 85 cm3 (mean 28.2 cm3; median 24 cm3). Angiography in 12 patients 1-21 years following radiation therapy demonstrated no significant change in 7, slight reduction in 2, near complete obliteration in 1, and complete obliteration in 2. Magnetic resonance imaging further demonstrated apparent obliteration in one other case. Three irradiated AVMs were available for pathological examination following fatal recurrent hemorrhage after 21 years in case 1 and following surgery after 5 years in cases 2 and 3. Doses of 20 and 45 Gy were delivered to the area of the AVM in 10 and 15 fractions with a 6-MV linear accelerator in case 1 and in cases 2 and 3, respectively. A blinded histopathological comparison was made of the latter cases and three AVMs removed at surgery that were not previously irradiated and that were comparable in size, number of arterial feeders, and location within the brain. Segmental hyalinization of some blood vessels was seen in both irradiated and nonirradiated cases. The single postmortem specimen showed extensive thrombosis but a patent nidus. The findings are in keeping with the clinical impression that conventional fractionated radiation therapy fails to alter the natural history of cerebral AVMs. The favorable outcome of radiosurgery on small- to medium-sized AVMs appears attributable to the shorter duration of therapy using relatively high-dose prescriptions to the nidus.

Adult↗

PubMed1994

Biodegradation of distal shunt catheters.

In a review of pediatric and adult distal cerebrospinal fluid shunt failures, the distal catheters were found to have deteriorated to the point of malfunction in 7 individuals after intervals of over 7 years. All cases presented in the first two decades of life with a duration of symptoms ranging from 1 to 62 days. The mechanism of shunt failure was assessed by radionuclide shuntogram study and at surgery. Degradation of catheter material led to irregular attenuation and fracture of the catheter wall with diffuse leakage of radionuclide into surrounding tissues. The catheter length of most chronic duration following implant was inevitably affected. Radionuclide shuntogram study of the distal catheter clearly identified the nature of the problem by showing an irregular outline of the catheter lumen due to spread of radioactivity into the surrounding soft tissues. Occasionally, intense foci of activity were identified at single or multiple sites where the catheter wall was grossly attenuated or fractured, resulting in cessation of catheter flow further distally. The biodegradability of distal shunt catheters leading to malfunction must be considered when assessing a young individual with features of hydrocephalus and a chronically implanted catheter length. Radionuclide shuntogram study is a convenient means of assessing the problem.

Adolescent↗

PubMed1994

Decompression for dysthyroid ophthalmopathy via the orbital rim approach. Technical note.

A technique is described wherein the approach to the orbital cavity, with resection of its roof and lateral wall, is facilitated by a single burr hole and local en bloc removal of the lateral and supraorbital margins. A satisfactory decompression with reduction of proptosis of the orbital contents and a good cosmetic result is achieved without the need for a large dural exposure. The approach may be combined with removal of the anterior wall of the frontal sinus in cases where the lateral aspect extends appreciably laterally. Access to the orbital roof and lateral wall is straightforward and can be coupled with further removal of the floor lateral to the infraorbital nerve and medial wall. Advancement of the orbital rim upon bone replacement adds to orbital volume, creating better mechanical advantage for eyelid closure.

Adolescent↗