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L M Carey

Publications and source records attributed to L M Carey.

12 recordsLinked to original sources
PubMed2002

Reemergence of activation with poststroke somatosensory recovery: a serial fMRI case study.

The authors demonstrate the potential for poststroke return of activation in regions normally involved in touch discrimination in a serial, whole-brain fMRI study of a patient with marked sensory loss followed by good recovery. A return of activation in ipsilesional primary and bilateral secondary somatosensory cortices was observed at 3 months after stroke and was maintained at 6 months, indicating a reemergence of activation after the interval of somatosensory recovery. There was little evidence of neural plastic changes early after stroke (2 weeks), when sensory loss was severe.

Adult↗
PubMed2000

The functional neuroanatomy and long-term reproducibility of brain activation associated with a simple finger tapping task in older healthy volunteers: a serial PET study.

We examined long-term reproducibility of the functional organization of the brain associated with a simple finger tapping movement using positron emission tomography (PET). Repeat measurements of regional cerebral blood flow were obtained in 10 individuals, ages 35 to 82 years (mean 52 years), at scanning sessions separated by 6 months. Although the functional neuroanatomy of hand movements has previously been investigated with PET by a number of groups, none has reported systematic investigation of the consistency of brain activation over an extended time. As expected, we found significant activation in the left precentral gyrus [Talairach coordinate (-32, -34, 52)], postcentral gyrus (-22, -48, 56), and supplementary motor area (SMA) (-2, -18, 52) at the initial study, consistent with previous studies in younger subjects. For the follow-up study we also found significant activation in the left precentral (-36, -28, 52) and postcentral (-28, -36, 52) gyri and in the SMA (2, -16, 56). Our group results demonstrate consistent anatomical location and extent of motor activation over time. More importantly, analysis of individuals confirmed the presence of consistent sites of activation in primary sensorimotor cortex and SMA over the 6-month interval in most subjects. A high degree of consistency in location of activation in the group, and within individuals, over time suggests that changes in loci of activation may be confidently monitored using the PET method. Evidence of individual differences in extent of activation over time highlights the need for caution when interpreting similar changes in patient studies.

Adult↗
PubMed1999

Motor cortex localization using functional MRI and transcranial magnetic stimulation.

OBJECTIVE: Congenital brain lesions producing focal seizures may be accompanied by reorganization of the areas responsible for motor and sensory functions within the brain due to a phenomenon that has been termed "neuronal plasticity." This can be studied using functional MRI (fMRI) and transcranial magnetic stimulation (TMS). Using either method, the motor cortex can be localized noninvasively, but to date there have been few studies correlating the level of agreement between the two techniques. METHODS: We used fMRI and TMS to localize the motor cortex in a young woman with intractable focal seizures, congenital left arm weakness, and a dysplastic right hemisphere on MRI. RESULTS: There was excellent agreement in the localization of motor representation for each hand. Both were predominantly located in the left hemisphere. fMRI also showed an area of posterior activation in the right hemisphere, but there was no evidence of descending corticospinal projections from this site using TMS, direct cortical stimulation, and Wada testing. CONCLUSIONS: Functional MRI (fMRI) and transcranial magnetic stimulation (TMS) were successfully used to localize cortical motor function before epilepsy surgery. Each technique demonstrated migration of motor function for the left hand to the left motor cortex. After resection of the dysplastic right precentral gyrus there was no permanent increase in weakness or disability. The two techniques are complementary; fMRI indicates all cortical areas activated by the motor task, whereas TMS identifies only those areas giving rise to corticospinal projections.

Adult↗
PubMed1998

Clinical and echocardiographic findings in patients with suspected acute aortic dissection.

OBJECTIVES: The objective of this study was to define the range of clinical presentations, echocardiographic findings, and underlying final diagnoses in patients with clinically suspected acute aortic dissection. METHODS AND RESULTS: This study was designed as a retrospective review of clinical and echocardiographic data in consecutive patients evaluated for clinically suspected acute aortic dissection. The study population consisted of 75 studies in 74 consecutive patients referred for urgent or emergency evaluation because of signs and symptoms suggesting acute aortic dissection. A history and physical examination designed to elicit the cause of chest pain, evidence of congestive heart failure, and other cardiovascular abnormalities was performed in each patient. All patients underwent transesophageal echocardiography by experienced operators. Routine 12-lead electrocardiograms and chest radiographs were available for review in the majority of patients. Magnetic resonance imaging or computed tomography was performed in only 5 (6%) and 34 (44%) patients, respectively. Contrast aortography was performed in 21 (27%) patients. For the entire patient cohort, the most prevalent symptom was chest pain alone (n = 31; 41%) or chest pain in conjunction with back pain (n = 23; 31%). Classic "tearing" pain was an infrequent symptom. Syncope or other neurologic findings were present in 15 (20%) patients. Acute aortic dissection was responsible for 34 (45%) of the 75 presentations, with 31 (41% of total evaluations, 92% of dissections) involving the ascending aorta (Stanford type A, DeBakey type 1 or 2). Alternate major cardiovascular diagnoses, including acute myocardial infarction, primary valvular disease, or pericardial disease, were established in 12 (16%) cases. Aortic pathology, other than dissection, was found in 15 (20%) cases. Transesophageal echocardiography established the diagnosis responsible for the symptoms in 61 (81%) cases. CONCLUSIONS: Symptoms in patients with acute aortic dissection are more variable than commonly recognized. Transesophageal echocardiography is an accurate primary diagnostic tool in patients with clinically suspected acute aortic dissection. It allows rapid diagnosis of dissection and can identify alternate cardiovascular pathology responsible for the symptoms in a significant number of patients without acute dissection.

Aged↗
PubMed1996

Impaired limb position sense after stroke: a quantitative test for clinical use.

OBJECTIVE: A quantitative measure of wrist position sense was developed to advance clinical measurement of proprioceptive limb sensibility after stroke. Test-retest reliability, normative standards, and ability to discriminate impaired and unimpaired performance were investigated. DESIGN: Retest reliability was assessed over three sessions, and a matched-pairs study compared stroke and unimpaired subjects. Both wrists were tested, in counterbalanced order. SETTING: Patients were tested in hospital-based rehabilitation units. PATIENTS AND OTHER PARTICIPANTS: Reliability was investigated on a consecutive sample of 35 adult stroke patients with a range of proprioceptive discrimination abilities and no evidence of neglect. A consecutive sample of 50 stroke patients and convenience sample of 50 healthy volunteers, matched for age, sex, and hand dominance, were tested in the normative-discriminative study. Age and sex were representative of the adult stroke population. MAIN OUTCOME MEASURES: The test required matching of imposed wrist positions using a pointer aligned with the axis of movement and a protractor scale. RESULTS: The test was reliable (r = .88 and .92) and observed changes of 8 degrees can be interpreted, with 95% confidence, as genuine. Scores of healthy volunteers ranged from 3.1 degrees to 10.9 degrees average error. The criterion of impairment was conservatively defined as 11 degrees (+/-4.8 degrees) average error. Impaired and unimpaired performance were well differentiated. CONCLUSIONS: Clinicians can confidently and quantitatively sample one aspect of proprioceptive sensibility in stroke patients using the wrist position sense test. Development of tests on other joints using the present approach is supported by our findings.

Adult↗
PubMed1993

Sensory loss in stroke patients: effective training of tactile and proprioceptive discrimination.

Although somatosensory loss following stroke is common, with negative consequences for functional outcome, studies of existing somatosensory retraining programs are limited by theoretical weaknesses, poor methodology, and negative findings. We, therefore, developed a new program for stroke patients and investigated its effect on tactile discrimination in four AB, single-case quasi-experiments and its effect on tactile and proprioceptive discrimination in four multiple-baseline experiments. Training involved specific, graded discrimination tasks, attentive exploration of stimuli with vision occluded, deliberate anticipation, and quantitative feedback. Graphic and statistical interrupted time-series analyses indicated that treatment produced improvements in seven of eight tactile time series and all four proprioceptive time series. Baseline improvement in one tactile time series prevented unequivocal evaluation of treatment effect. Improvements were clinically significant, discrimination in the affected hand becoming comparable to the other hand and normal performance. Therapeutic effects were maintained at 3-month to 5-month follow-up tests.

Adult↗
PubMed1984

Generation of fatty acids by an acyl esterase in the bioluminescent system of Photobacterium phosphoreum.

The fatty acid reductase complex from Photobacterium phosphoreum has been discovered to have a long chain ester hydrolase activity associated with the 34K protein component of the complex. This protein has been resolved from the other components (50K and 58K) of the fatty acid reductase complex with a purity of greater than 95% and found to catalyze the transfer of acyl groups from acyl-CoA primarily to thiol acceptors with a low level of transfer to glycerol and water. Addition of the 50K protein of the complex caused a dramatic change in specificity increasing the transfer to oxygen acceptors. The acyl-CoA hydrolase activity increased almost 10-fold, and hence free fatty acids can be generated by the 34K protein when it is present in the fatty acid reductase complex. Hydrolysis of acyl-S-mercaptoethanol and acyl-1-glycerol and the ATP-dependent reduction of the released fatty acids to aldehyde for the luminescent reaction were also demonstrated for the reconstituted fatty acid reductase complex, raising the possibility that the immediate source of fatty acids for this reaction in vivo could be the membrane lipids and/or the fatty acid synthetase system.

Aldehyde Oxidoreductases↗