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Biomedical subjects

R E Gross

Publications and source records attributed to R E Gross.

At least 19 recordsLinked to original sources
PubMed2001

Cognitive deficits in patients with essential tremor.

OBJECTIVE: To assess cognitive and affective functioning in patients with essential tremor (ET). BACKGROUND: ET is traditionally thought to occur in isolation, without other neurologic abnormalities or cognitive changes. Recent evidence of gait disturbance and bradykinesia in these patients suggests that the neurologic abnormalities in ET may be more widespread than was once thought. Cognitive function in these patients has not been the subject of in-depth study. METHODS: Cognitive performance and mood were assessed in 18 consecutive patients with ET and 18 consecutive patients with PD who visited the neurosurgical clinic for surgical treatment of their symptoms. RESULTS: The patients with ET were found to have deficits on tests of verbal fluency, naming, mental set-shifting, verbal memory, and working memory, as well as higher levels of depression. In contrast to these areas of deficit, their performance was better than that of the normative sample on several tests of verbal and nonverbal conceptualization and reasoning. Tremor severity was not correlated with cognitive deficits. Patients with PD had deficits on the same tests that were impaired in the ET group and on tests of visuospatial processes. Direct comparison of the ET and PD groups showed greater impairment in facial perception in the PD group and greater impairment in verbal fluency and working memory in the ET group. CONCLUSION: Patients with ET have deficits in specific aspects of neuropsychological functioning, particularly those thought to rely on the integrity of the prefrontal cortex, which suggests involvement of frontocerebellar circuits in this disease.

Adult↗
PubMed2001

Neural activity related to drug craving in cocaine addiction.

BACKGROUND: Crack cocaine dependence and addiction is typically associated with frequent and intense drug wanting or craving triggered by internal or environmental cues associated with past drug use. METHODS: Water O 15 positron emission tomography (PET) studies were used to localize alterations in synaptic activity related to cue-induced drug craving in 8 crack cocaine-dependent African American men. In a novel approach, script-guided imagery of autobiographical memories were used as individualized cues to internally generate a cocaine craving state and 2 control (ie, anger and neutral episodic memory recall) states during PET image acquisition. RESULTS: The mental imagery of personalized drug use and anger-related scripts was associated with self-ratings of robust drug craving or anger, and comparable alterations in heart rate. Compared with the neutral imagery control condition, imagery-induced drug craving was associated with bilateral (right hemisphere amygdala activation greater than left) activation of the amygdala, the left insula and anterior cingulate gyrus, and the right subcallosal gyrus and nucleus accumbens area. Compared with the anger control condition, internally generated drug craving was associated with bilateral activation of the insula and subcallosal cortex, left hippocampus, and anterior cingulate cortex and brainstem. A brain-wide pixel-by-pixel search indicated significant positive and negative correlations between imagery-induced cocaine craving and regional cerebral blood flow (rCBF) in distributed sites. CONCLUSIONS: The collected findings suggest the craving-related activation of a network of limbic, paralimbic, and striatal brain regions, including structures involved in stimulus-reward association (amygdala), incentive motivation (subcallosal gyrus/nucleus accumbens), and anticipation (anterior cingulate cortex).

Adult↗
PubMed2000

Breast cancer: risk factors, screening, and prevention.

OBJECTIVES: To provide a review of the major and minor risk factors for the development of breast cancer and the options for prevention and treatment in women at high risk for breast cancer. DATA SOURCES: Clinical and research articles and textbooks. CONCLUSIONS: Breast cancer is the leading cancer found in women in the United States. For high-risk women, understanding their risk, appropriate screening recommendations, and possible prevention strategies is paramount. IMPLICATIONS FOR NURSING PRACTICE: Through education and psychosocial support, the nurse can assist with decision-making regarding risk reduction and current prevention and treatment options.

Aged↗
PubMed2000

Advances in neurostimulation for movement disorders.

In just 12 years since its introduction, deep brain stimulation (DBS) has become well established as a safe and effective therapy in the treatment of medically refractory movement disorders. Ventralis intermedius (Vim) DBS has virtually replaced thalamotomy in the routine clinical treatment of essential tremor, affording relief to thousands of patients who previously would not have undergone surgery, and there is increasing usage of Vim DBS in other tremors of intention (e.g., multiple sclerosis). Subthalamic nucleus (STN) and globus pallidus internus (GPi) DBS have revolutionized the treatment of advanced stage Parkinson's disease, improving all cardinal disease features and increasing 'on' time without dyskinesias. Finally, DBS of various sub-cortical structures is being developed and tested in other less prevalent movement disorders such as dystonia. Future developments in this rapidly advancing area will no doubt include widening indications for this relatively safe surgical procedure, elucidation of the mechanisms of action of electrical stimulation, and technological advancements improving effectiveness and convenience.

Brain↗
PubMed2000

Relationship of lesion location to cognitive outcome following microelectrode-guided pallidotomy for Parkinson's disease: support for the existence of cognitive circuits in the human pallidum.

Current models of basal ganglia anatomy posit the existence of multiple parallel, anatomically segregated circuits. Anatomical data from non-human primates suggest that the circuits subserving motor functions are segregated from those subserving cognitive functions. Here we present data that demonstrate that, in humans, motor and cognitive frontosubcortical circuits are segregated. We studied a group of patients with Parkinson's disease undergoing surgical lesioning of the globus pallidus internus for relief of their symptoms. Lesion location along an anteromedial-to-posterolateral axis was found to be related to postsurgical outcome on both cognitive and motor measures. Performance on several neuropsychological measures, including the generation of category exemplars and continuous mental addition, was linearly related to distance along this axis, with anteromedial lesions leading to postsurgical impairment, intermediate lesions having little effect and posterolateral lesions leading to an improvement on several measures. The same relationship was found between memory performance under conditions of proactive interference and lesion location within the globus pallidus internus. In contrast, bradykinesia, assessed as the speed of finger-tapping, had a non-linear relationship to lesion location, intermediate lesions leading to greater postsurgical improvement than lesions in more extreme anteromedial or posterolateral locations. These data demonstrate that the cognitive effects of pallidotomy can be dissociated from the motor effects. These effects depend upon the placement of the lesions within the globus pallidus internus, supporting the segregation of functionally distinct circuits in the human pallidum.

Cognition↗
PubMed1999

Posteroventral medial pallidotomy in Parkinson's disease.

There has been a resurgence in the use of functional neurosurgery for Parkinson's disease. An important factor that has played a role in this development is the recent understanding of the functional anatomy of the basal ganglia including a knowledge of the changes in the activities of neurons in the internal segment of the globus pallidus (Gpi) and the subthalamic nucleus (STN) in Parkinson's disease as well as the knowledge of the presence of segregated functional loops within the basal ganglia which include a sensory-motor loop that involves the posteromedial globus pallidus rather than the anterior GPi where earlier pallidotomy lesions had been made. Laitinen reintroduced the modern posteroventral medial pallidotomy (PVMP) in 1992. Since then it has become clear that this treatment has major effects on levodopa-induced dyskinesias and, unlike Vim thalamotomy, improves bradykinesia and rigidity as well as tremor. In this report, we review a number of topics related to PVMP including the clinical results of pallidotomy available in the literature as well as an update of our own 2 year follow-up data, studies evaluating factors that might predict the subsequent response to pallidotomy, the neuropsychological effects of the procedure, results of imaging studies including the correlation of clinical effects with lesion location, the question of bilateral pallidotomy and pallidotomy combined with deep brain stimulation and finally whether PVMP is effective in other parkinsonian disorders.

Globus Pallidus↗
PubMed1999

New developments in the surgery for Parkinson's disease.

Despite optimization of medical therapy, a large number of patients with Parkinson's disease continue to be disabled. For this group, alternate treatment strategies such as neurosurgical intervention can be considered. Recent advances in neurosurgical techniques and in understanding the pathophysiology of motor disturbances in PD have made surgery safer and more effective. Functional neurosurgical procedures to lesion or electrically modulate dysfunctional basal ganglia circuits or to protect or restore dopaminergic transmission are being increasingly used. These procedures are having a profound impact on the motor disturbances of PD and are producing important improvements in quality of life of patients.

Adrenal Medulla↗
PubMed1999

Wisconsin Card Sorting Test performance following head injury: dorsolateral fronto-striatal circuit activity predicts perseveration.

The Wisconsin Card Sorting Test (WCST) has been argued to be a sensitive indicator of frontal lobe function. However, several recent studies have failed to find a consistent relationship between structural damage to this cortical area and perseveration on the test. In the present study, positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose was used to examine the relationship of regional brain metabolism to perseverative responding on the WCST in patients with a history of closed-head injury. An inverse relationship was found between perseverative responses and metabolism in the right, but not the left, dorsolateral prefrontal cortex and caudate nucleus. Perseverative responding was not related to metabolism in several other regions of the frontal lobes and basal ganglia, including the putamen and the frontal poles bilaterally. These data suggest that the functional integrity of the right dorsolateral frontal-subcortical circuit is critical for WCST performance.

Adult↗
PubMed1999

Relationship of lesion location to clinical outcome following microelectrode-guided pallidotomy for Parkinson's disease.

The purpose of this study was to examine the relationship between lesion location and clinical outcome following globus pallidus internus (GPi) pallidotomy for advanced Parkinson's disease. Thirty-three patients were prospectively studied with extensive neurological examinations before and at 6 and 12 months following microelectrode-guided pallidotomy. Lesion location was characterized using volumetric MRI. The position of lesions within the posteroventral region of the GPi was measured, from anteromedial to posterolateral along an axis parallel to the internal capsule. To relate lesion position to clinical outcome, hierarchical multiple regression analysis was used. The variance in outcome measures that was related to preoperative scores and lesion volume was first calculated, and then the remaining variance attributable to lesion location was determined. Lesion location along the anteromedial-to-posterolateral axis within the GPi influenced the variance in total score on the Unified Parkinson's Disease Rating Scale in the postoperative 'off' period, and in 'on' period dyskinesia scores. Within the posteroventral GPi, anteromedial lesions were associated with greater improvement in 'off' period contralateral rigidity and 'on' period dyskinesia, whereas more centrally located lesions correlated with better postoperative scores of contralateral akinesia and postural instability/gait disturbance. Improvement in contralateral tremor was weakly related to lesion location, being greater with posterolateral lesions. We conclude that improvement in specific motor signs in Parkinson's disease following pallidotomy is related to lesion position within the posteroventral GPi. These findings are consistent with the known segregated but parallel organization of specific motor circuits in the basal ganglia, and may explain the variability in clinical outcome after pallidotomy and therefore have important therapeutic implications.

Aged↗
PubMed1999

The relationship of magnetic source imaging to ictal electrocorticography in a neuronavigational workspace.

Magnetic source imaging (MSI) registers magnetoencephalographic (MEG) activity to a three-dimensional MRI volume. State-of-the-art MSI allows concurrent whole head coverage, but is practically restricted to interictal recording. However, the purpose of the presurgical evaluation of epileptic patients, in which MSI is playing an increasing role, is the elucidation of the ictal epileptogenic focus. The manner in which interictal MSI activity relates to the ictal focus has not yet been adequately examined. To facilitate this analysis, we are developing techniques to precisely coregister MSI to the ictal onset zone as defined by extraoperative intracranial grid/strip monitoring. The neuronavigational workspace is a convenient area in which to precisely coregister these (and other) imaging and physiological data sets.

Cerebral Cortex↗
PubMed1999

Variability in lesion location after microelectrode-guided pallidotomy for Parkinson's disease: anatomical, physiological, and technical factors that determine lesion distribution.

OBJECT: To understand the factors that determine the distribution of lesions after microelectrode-guided pallidotomy for Parkinson's disease, the authors quantitatively characterized lesion location in a cohort of patients who were prospectively followed to determine the effects of pallidotomy on clinical outcome. METHODS: Thirty-three patients underwent volumetric magnetic resonance (MR) imaging after surgery to allow quantitative lesion localization in relation to conventional intraventricular landmarks and, alternatively, more anatomically relevant landmarks. The validity of the method was verified in a cohort of postpallidotomy patients who underwent concurrent volumetric and stereotactic MR imaging in an external head frame. Lesions were distributed over a considerable distance in the anteroposterior (8.8 mm) and mediolateral (8.7 mm) dimensions in relation to the anterior commissure and wall of the third ventricle, respectively. Less variation was seen in lesion location in the dorsoventral dimension (4.8 mm) in relation to the intercommissural plane. CONCLUSIONS: Lesion distribution was not random: lesion locations in the anteroposterior and mediolateral dimensions were highly correlated, such that lesions were distributed from anteromedial to posterolateral, parallel to the border of the globus pallidus internus with the obliquely oriented internal capsule. The factors that led to variability in lesion location were variation in third ventricle width and the oblique anteromedial-to-posterolateral course of the internal capsule. This demonstration of variability of lesion location in a cohort of patients who experienced excellent clinical benefits and minimal postoperative complications emphasizes the importance of anatomical variations in determining lesion position and the need for physiological corroboration for correct lesion placement.

Adult↗
PubMed1999

A flowsheet for documenting independent nursing visits after breast surgery.

PURPOSE/OBJECTIVES: To redesign a postoperative flowsheet already used in clinical practice with patients who have undergone breast surgery to reflect documentation of assessments and interventions noted on each nursing visit. DATA SOURCES: Memorial Sloan-Kettering Cancer Center Standards of Practice for Ambulatory Care, clinical experience, and published articles. DATA SYNTHESIS: A comprehensive flowsheet was redesigned to provide consistency in documentation and reflect current needs of patients who have undergone breast surgery who are in ambulatory care. CONCLUSIONS: Implementation of the new flowsheet has decreased staff documentation time during busy office practices and accurately reflects the nursing care provided to patients after breast surgery. IMPLICATIONS FOR NURSING PRACTICE: Consistency in patient care can be maintained and efficiency can be increased with use of a comprehensive flowsheet.

Ambulatory Care↗
PubMed1998

Current issues in the surgical treatment of early stage breast cancer.

Surgery remains the primary treatment for early stage breast cancer. Modified radical mastectomy and lumpectomy with axillary dissection continue to be the two procedures most commonly performed. Changes in the healthcare system and advances in medical research in cancer treatment affect the nursing care of these patients. The introduction of the sentinel node biopsy may change certain aspects of surgical treatment, as some patients may not require an axillary dissection. The challenge for nurses is to provide quality care and maintain established standards for patients with breast cancer as their hospitalizations are shortened to same day or overnight stays. The purpose of this article is to review the standard surgical treatments and related nursing care and discuss the impact of the sentinel node biopsy and the impact of changes in the length of hospital stay on the care of women with breast cancer.

Breast Neoplasms↗
PubMed1997

Globus pallidus internus pallidotomy for generalized dystonia.

The authors present a young boy with severe generalized dystonia treated with bilateral simultaneous pallidotomy. Microelectrode recordings with the patient under propofol anesthesia showed that the mean discharge rate of globus pallidus internus (GPi) neurons was between 21 and 31 Hz. This contrasts sharply with the mean GPi neuronal firing rates of approximately 80 Hz that are characteristic of Parkinson's disease. The patient had no immediate benefit from surgery, but a progressive improvement in both axial and limb dystonia began within 3 days. The Burke-Fahn-Marsden scores were 75 (maximum possible = 120) at baseline, 52 at 5 days, and 16 at 3 months after surgery. The mechanism of action of pallidotomy for dystonia and the reasons for the delayed and progressive improvement are unknown. Nevertheless, the magnitude of the improvement and the safety of the procedure in this one patient warrant a careful evaluation of pallidotomy for dystonia.

Anesthesia, General↗
PubMed1997

The effects of pallidotomy on Parkinson's disease: study design and assessment techniques.

Lesions of the internal segment of the globus pallidus are increasingly being utilized in the surgical treatment of advanced Parkinson's disease, yet studies to demonstrate the safety and efficacy of these procedures are only now being completed. The importance of procedural variations between centres in the outcome of pallidotomy is not yet known. In order to compare accurately results between centres, carefully designed, prospective studies are needed. The authors utilized blinded, randomly evaluated videotaped examinations of pre- and post-operative patients undergoing microelectrode-guided GPi pallidotomy. Their results demonstrate significant effects on contralateral akinesia and tremor in the "off" state, and striking attenuation of levodopa-induced dyskinesias in the "on" state. More modest effects on postural stability and gait disturbance were seen only in non-blinded evaluations. This type of study design should enable many of the outstanding issues related to pallidotomy indications, procedures and outcomes to be addressed.

Adult↗
PubMed1997

The Special Surveillance Breast Program: a model of intervention for women at high risk for breast cancer.

The Special Surveillance Breast Program (SSBP) is a long-term, comprehensive, multidisciplinary program for women determined to be at high risk for the development of breast cancer. Because the women who attend this program are otherwise healthy but concerned about their risk for breast cancer, current and relevant information is required to address their concerns regarding the possibility of developing breast cancer. The purpose of this article is to describe the risk factors that indicate eligibility for the program, the structure of the program, and the results of an assessment that identified the needs of this special population.

Adult↗
PubMed1996

Interleukin-7 is trophic for embryonic neurons and is expressed in developing brain.

Interleukin-7 (IL7) is a hematopoietic cytokine with critical functions in both B- and T-lymphocyte development. In this study, we find that IL7 exhibits trophic properties in the developing brain as well. Treatment of cultures of embryonic brain with exogenous IL7 increases neuronal survival and results in greater numbers of cells manifesting neurite outgrowth. As demonstrated with single-cell cultures, IL7 acts directly to promote neuronal survival. Expression of the mRNA encoding the high-affinity IL7 receptor (IL7R) is observed in vitro in neurons as well as in subventricular zone progenitor cells. Phosphorylation of p59fyn, which is activated by IL7 in pre-B cells and is thought to be important in neural development, occurs rapidly following IL7 treatment of cultured embryonic neurons. Additionally, the expression of c-myc mRNA, which is modulated by IL7 in lymphoid cells, is upregulated by IL7 in the same CNS cultures. Finally, the messenger RNAs encoding IL7 and IL7R are expressed in vivo in developing brain. The direct neurotrophic properties of IL7 combined with the expression of ligand and receptor in developing brain suggest that IL7 may be a neuronal growth factor of physiological significance during central nervous system (CNS) ontogeny.

Animals↗