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Biomedical subjects

G J Harris

Publications and source records attributed to G J Harris.

At least 73 records · Page 4Linked to original sources
PubMed1994

Decreased regional cortical gray matter volume in schizophrenia.

OBJECTIVE: The authors hypothesized that cortical gray matter volume reduction in schizophrenia is greatest in the heteromodal association cortex. This area comprises a highly integrated, reciprocally interconnected system that coordinates higher order cortical functions. METHOD: Total brain and regional gray matter volumes were calculated in 46 schizophrenic patients and 60 age and sex-matched comparison subjects by using magnetic resonance images. Disease specificity was examined by assessing 27 patients with bipolar disorder. Approximations to the dorsolateral prefrontal cortex, inferior parietal lobule, and superior temporal gyrus were selected as regions of interest for the heteromodal association cortex. Occipital and sensorimotor areas were used as comparison regions to test the hypothesis for regional specificity. RESULTS: Gray matter volume was reduced in schizophrenic patients in index regions even after covariance for overall brain volume, sex, and age. Bipolar disorder patients did not exhibit heteromodal gray matter reduction. Comparison regions did not differ among the three groups. Global gray matter volume was not different among groups after covariance for global brain volume. Comprehensive individual region post hoc analysis found no additional gray matter differences. CONCLUSIONS: These findings support the theory of disproportionate reduction of gray matter volume in the heteromodal association cortex specific to schizophrenia.

Adult↗
PubMed1994

Reduced basal ganglia volume associated with the gene for Huntington's disease in asymptomatic at-risk persons.

Previous investigations using linear CT measures found no evidence of caudate atrophy in asymptomatic persons who have the DNA haplotype linked to the Huntington's disease (HD) gene. We measured volumes of the caudate, putamen, and globus pallidus on MRIs of 10 gene marker-positive and 18 gene marker-negative asymptomatic at-risk persons. The volumes of all basal ganglia structures were significantly reduced in the marker-positive group, even after controlling for age, total brain volume, and minor neurologic signs. Discriminant function analysis using basal ganglia volumes and age as predictor variables correctly identified genetic status in 86% of subjects. These results indicate that basal ganglia volume is reduced before individuals become symptomatic with HD.

Adult↗
PubMed1994

MR volume segmentation of gray matter and white matter using manual thresholding: dependence on image brightness.

PURPOSE: To describe a quantitative MR imaging segmentation method for determination of the volume of cerebrospinal fluid, gray matter, and white matter in living human brain, and to determine the method's reliability. METHODS: We developed a computer method that allows rapid, user-friendly determination of cerebrospinal fluid, gray matter, and white matter volumes in a reliable manner, both globally and regionally. This method was applied to a large control population (N = 57). RESULTS: Initially, image brightness had a strong correlation with the gray-white ratio (r = .78). Bright images tended to overestimate, dim images to underestimate gray matter volumes. This artifact was corrected for by offsetting each image to an approximately equal brightness. After brightness correction, gray-white ratio was correlated with age (r = -.35). The age-dependent gray-white ratio was similar to that for the same age range in a prior neuropathology report. Interrater reliability was high (.93 intraclass correlation coefficient). CONCLUSIONS: The method described here for gray matter, white matter, and cerebrospinal fluid volume calculation is reliable and valid. A correction method for an artifact related to image brightness was developed.

Adult↗
PubMed1993

Primary left atrial myxosarcoma.

A patient in whom rapidly progressive congestive heart failure developed due to the presence of a left atrial myxosarcoma is described. The histologic picture is consistent with the hypothesis that cardiac myxoid tumors are neoplasms derived from undifferentiated cells found in the endocardium. Unfortunately, most cardiac malignancies are detected too late for curative resection, and palliation remains the mainstay of therapy.

Adult↗
PubMed1993

MRI-guided region of interest placement on emission computed tomograms.

The reliability of the placement of regions of interest (ROIs) on emission computed tomograms (ECT) with a semi-automated magnetic resonance image (MRI)-guided method was compared with the reliability of manual ROI placement. MRI-defined regions were transferred to the registered, co-planar ECT image after accounting for inter-image differences in rotation, translation, and scaling. Six single photon emission computed tomographic (SPECT) scans of normal control subjects were rated for caudate perfusion using the radiotracer N-isopropyl[I-123]-iodoamphetamine (IMP). The MRI-guided method had higher interrater reliability, lower variance of region location, and lower variance of region activity than the manual method. The manual method recorded higher mean regional activity than the MRI-guided method, possibly due to sample bias inherent in the manual method.

Analysis of Variance↗
PubMed1993

Foramen of Morgagni hernia in identical twins: is this an inheritable defect?

Twins with Down's syndrome, foramen of Morgagni hernias, and similar cardiac anomalies are described. While diaphragmatic hernias are not uncommon, the occurrence of this congenital defect in twins with very similar congenital anomalies raises the possibility that diaphragmatic hernias may result from an inheritable defect.

Abnormalities, Multiple↗
PubMed1993

Quantitative D2 dopamine receptor PET and structural MRI changes in late-onset schizophrenia.

Late-onset schizophrenia (LOS) is likely a syndrome of diverse etiology. In a series of related studies, we compared LOS patients with normal controls, elderly patients with early-onset schizophrenia (EOS), and Alzheimer's disease patients, using magnetic resonance imaging (MRI) and neuroreceptor positron emission tomography measures, which had previously been reported to be abnormal in EOS. EOS and LOS patients showed similar MRI changes. LOS drug-naive patients had elevated Bmax (receptor density) values for dopamine D2 receptors compared with age and gender norms, a phenomenon previously reported by our group in young schizophrenia patients.

Aged↗
PubMed1993

Correlation of acute cocaine-induced changes in local cerebral blood flow with subjective effects.

The authors administered 48 mg of intravenous cocaine or placebo to eight abstinent cocaine users in a double-blind, crossover design and examined blood flow using single photon emission computed tomography. Cocaine produced significant decreases in frontal cortical and basal ganglia blood flow; these latter correlated negatively with increases in self-ratings of "rush" and "high." The authors conclude that these local effects are compatible with dopaminergic system involvement.

Adult↗
PubMed1993

Reduced basal ganglia volume in HIV-1-associated dementia: results from quantitative neuroimaging.

Although brain atrophy is a common neuroradiologic and pathologic finding in patients with HIV-1 infection, especially those with HIV-1-associated dementia complex, it is not clear whether specific regions of the brain are differentially responsible for tissue loss. In this study, we measured volumes of basal ganglia structures on MRIs for three groups: HIV-1-infected homosexual men with HIV-1-associated dementia complex (HIV+ demented), HIV-1-infected homosexual men without HIV dementia (HIV+ nondemented), and noninfected homosexual men. All groups were comparable on age and years of education, and the HIV+ groups were comparable on level of immunosuppression. Total brain volume was smaller in the HIV+ nondemented patients in comparison with HIV- control subjects; the HIV+ demented patients demonstrated even smaller brain volumes than the HIV+ nondemented patients. Smaller basal ganglia volumes, after corrections for intracranial volume, distinguished HIV+ demented patients from the other two groups; there were no differences between the HIV+ nondemented and HIV- groups on basal ganglia volumes. This study suggests that HIV infection causes generalized brain atrophy, but that the clinical features of HIV dementia develop with selective basal ganglia atrophy, consistent with the characterization of HIV dementia as subcortical.

AIDS Dementia Complex↗
PubMed1993

Age as a factor in the bacteriology and response to treatment of subperiosteal abscess of the orbit.

The clinical course of SPA of the orbit is associated with the age of the patient. That association might be explained through a series of intermediate relationships: the clinical course correlates with the bacterial constituency, the bacterial constituency is related to physiologic derangement within the sinuses, the physiologic derangement may vary with the degree of obstruction of the sinus ostia, and the ostial caliber relative to the volume of the cavity that must be drained decreases with patient age into late adolescence. The controversy between pediatricians and surgeons over the appropriate indications for drainage might be resolved with the acknowledgement that each side is correct on the basis of the patient populations treated. It is hoped that recognition of the age-related variations in SPA will permit a more systematic approach to the management of this complex infectious disease.

Abscess↗
PubMed1992

Hispanic patients with head and neck cancer do not have a worse prognosis than Anglo-American patients.

This study was undertaken to determine whether the survival of Hispanic patients with squamous cell carcinoma of the head and neck was different from that of Anglo-American patients. The charts of 275 male patients with a diagnosis of squamous cell carcinoma of the head and neck at one Veterans Administration Hospital were reviewed in an attempt to identify prognostic indicators for both ethnic groups. No differences were observed between Anglo-American and Hispanic patients with respect to sites of the primary tumor, age at diagnosis, performance status, or the frequency of surgery, radiation therapy, or chemotherapy; however, there was a tendency for Hispanic patients to have received more treatment. There also was a trend (P = 0.12) for Hispanic patients to have a more advanced stage of cancer. Hispanic patients lost significantly more weight (P less than 0.001) and had significantly lower serum albumin levels (P less than 0.0001). According to the results of multivariate survival analyses, the variables that were predictive of a poor prognosis included advanced stage of disease, decreased serum albumin levels, increased weight loss, administration of chemotherapy, lack of radiation therapy or surgery, and advanced age. Ethnicity was not a significant predictor of survival either in univariate analyses, or within patients with the same stage of disease, or after adjustment for other prognostic factors. In conclusion, the natural history of squamous cell carcinoma of the head and neck is the same for Hispanic and Anglo-American patients.

Carcinoma, Squamous Cell↗
PubMed1992

Surgical dissection of capillary hemangiomas. An alternative to intralesional corticosteroids.

Intralesional corticosteroids are often successful in reducing the size of functionally significant capillary hemangiomas. While they may have a better benefit-risk ratio than some earlier treatment methods, a number of serious complications have been reported recently. We believe these resulted from the hemodynamic continuity of capillary hemangiomas with the orbital and systemic circulation and that intralesional injections are intravascular. Surgery has generally been avoided because capillary hemangiomas are not encapsulated and piecemeal resection can produce significant bleeding. In carefully selected patients, we have used a surgical approach that involves dissection on the tumor's surface without entering its substance. Hemangiomas were removed en bloc from five patients with insignificant blood loss and excellent anatomic restoration.

Capillaries↗
PubMed1992

Quantitative changes in mesial temporal volume, regional cerebral blood flow, and cognition in Alzheimer's disease.

Twenty-six patients with moderately severe Alzheimer's disease (AD) and 16 normal control subjects were studied using either quantitative magnetic resonance imaging (MRI) measures of mesial temporal atrophy (15 patients with AD and 16 normal control subjects) and/or quantitative radioactive iodine 123-N-isopropyl-iodoamphetamine single-photon emission computed tomography (SPECT) assessment of regional cerebral blood flow (20 patients with AD and eight normal control subjects). Nine individuals with AD and eight normal control subjects underwent both structural and functional imaging. On MRI, patients and controls were best discriminated using left amygdala and entorhinal cortex volumes, and on SPECT they were best discriminated by relative left temporoparietal cortex blood flow. Combining these MRI and SPECT measures yielded 100% discrimination. Relative left temporoparietal SPECT regional cerebral blood flow and left superior temporal gyral MRI volume correlated best with severity of cognitive deficit in patients with AD. Mesial temporal MRI atrophy exceeded generalized cerebral shrinkage. Both SPECT and MRI regional changes accorded with areas known to be affected by AD neuropathology.

Aged↗
PubMed1992

Putamen volume reduction on magnetic resonance imaging exceeds caudate changes in mild Huntington's disease.

The characteristic pathological features of Huntington's disease (HD) are neostriatal atrophy and neuronal loss. Although neuroradiological studies often show caudate atrophy in patients with moderate HD, frequently no caudate atrophy is found early in the illness. There have been no quantitative reports to date on in vivo putamen volume measures in mild HD, although the structure is known to be neuropathologically involved in the illness. We measured volumes of caudate nucleus and putamen and bicaudate ratios (BCR) from magnetic resonance images, blind to diagnosis, in 15 patients with mild HD and 19 age- and sex-matched control subjects using a computerized image analysis system. The region showing greatest atrophy was the putamen, which was reduced 50.1% in mean volume in HD patients compared with control subjects (p less than 0.000001). In contrast, caudate volume was reduced 27.7% (p = 0.004). BCR was increased 28.5% in HD patients (p = 0.0002). Discriminant function analysis was 94% effective in identifying the diagnostic group based on putamen volume alone, whereas caudate measures had considerable overlap. Correction of putamen volume for head size led to 100% separation by group. Putamen measures and BCR correlated with neurological examination scores but caudate volume did not. Volumetric measurement of putamen is a more sensitive indicator of brain abnormalities in mild HD than measures of caudate atrophy.

Adult↗
PubMed1992

DNA flow cytometry of sebaceous cell carcinomas of the ocular adnexa: introduction to the technique in the evaluation of periocular tumors.

DNA content abnormalities are well recognized in tumor cell biology and kinetics. We introduce the technique of DNA flow cytometry through the study of the sebaceous cell carcinomas of the ocular adnexa. By correlating the data to the standard histopathologic parameters of pagetoid changes, degree of anaplasia, and stromal inflammation, significant associations are revealed. All aneuploid tumors demonstrate pagetoid spread, and more severe anaplasia and stromal inflammation. All diploid tumors are nonpagetoid and have lesser degrees of anaplasia and stromal inflammation. A complete review of the technique with a discussion of the implications and applicability to the study of ocular adnexal tumors is presented.

Aged↗
PubMed1992

Blastomycosis of the eyelid and conjunctiva.

A 37-year-old man with a recurrent papillomatous lesion of the upper eyelid and four separate bulbar conjunctival ulcers was found to have North American blastomycosis. This represents the first reported case with conjunctival lesions that were not simply contiguous with eyelid involvement. This case underscores the importance of considering blastomycosis in the differential diagnosis of granulomatous conjunctivitis and when examining a lesion of the eyelid resembling a squamous cell carcinoma or atypical papilloma.

Adult↗