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Biomedical subjects

G Leonard

Publications and source records attributed to G Leonard.

At least 55 records · Page 3Linked to original sources
PubMed1991

Recall of the end-position of examiner-defined arm movements by patients with frontal- or temporal-lobe lesions.

Sixty-three patients with unilateral temporal- or frontal-lobe excisions and 14 normal control subjects were tested on a kinesthetic task in which they had to recall the end-position of arm movements determined by the examiner. Patients with left frontal-lobe or small right frontal-lobe excisions performed normally, whereas patients with temporal-lobe excisions that included extensive removal of the hippocampus performed poorly, but only after a delay during which an interpolated task was carried out. Subjects with large right frontal-lobe removals were impaired in delayed recall, and the presence of an interpolated task did not exacerbate the impairment, which was equal for the two arms. The results point to an important role played by the right frontal lobe in the maintenance of kinesthetic-location cues over time, but not in their initial encoding.

Adolescent↗
PubMed1991

Temporal lobe surgery for epilepsy: neuropsychological variables related to surgical outcome.

A retrospective study of 383 patients who had undergone either left or right anterior temporal lobectomy (varying with respect to the amount of hippocampus excised) revealed that there were no significant differences in surgical outcome between those patients having a large and those patients having a small hippocampal removal. Although left temporal-lobe excisions were significantly smaller than right temporal-lobe excisions, both medially and laterally, patients with left temporal-lobe removals had an overall better surgical outcome. Patients in the successful surgical-outcome group did better than the unsuccessful surgical-outcome group on a variety of cognitive measures, including tests of intelligence, delayed verbal memory, and verbal fluency. The results suggest that, for many patients with medically intractable epilepsy, an anterior temporal lobectomy including the amygdala may suffice to reduce their seizure frequency.

Adolescent↗
PubMed1991

Fine serotyping of human immunodeficiency virus serotype 1 (HIV-1) and HIV-2 infections by using synthetic oligopeptides representing an immunodominant domain of HIV-1 and HIV-2/simian immunodeficiency virus.

In this study, enzyme immunoassays for detection of type-specific antibodies to human immunodeficiency viruses (HIV) were developed by using short peptides corresponding to sequences located within the immunodominant domain of the transmembrane glycoproteins of both HIV-1 and HIV-2-simian immunodeficiency virus (SIV). The assays were highly sensitive with currently available sera from various geographical areas. Furthermore, they appeared to be more specific in HIV serotyping than the Western blot (immunoblot) assay, since all of the sera were clearly discriminated as one or the other type. It was also shown that in contrast to HIV-1, the C-terminal cysteine residue (amino acid 620, SIV from captive macaques, Mm142 strain) of the HIV-2-SIV peptide is not necessary for recognition of the peptide by antibody to HIV-2.

Amino Acid Sequence↗
PubMed1991

Characterization of cytokines present in middle ear effusions.

Retention of inflammatory mediators and cells in the middle ear cleft during chronic otitis media with effusion (COME), results in ongoing inflammation with the potential for pathologic changes and hearing loss. Cytokines are glycoproteins produced by macrophages and other cells. Activities of cytokines include fever production, osteoclast, fibroblast, phagocyte and cytotoxic cell activation, regulation of antibody formation, and inhibition of cartilage, bone and endothelial cell growth. Using enzyme-linked immunospecific assays we measured levels of six cytokines in middle ear effusions (MEE) from children with COME. Significant levels of four cytokines: interleukin-1-beta (greater than 50 pg/ml), interleukin-2 (greater than 300 pg/ml), tumor necrosis factor-alpha (greater than 40 pg/ml), and gamma-interferon (greater than 6.25 pg/ml) were found in 51%, 54%, 63%, and 19% of MEE, respectively. In contrast, levels of a fifth cytokine, granulocyte-macrophage colony-stimulating factor, and a sixth cytokine, interleukin-4, were undetectable. Age was observed to have a significant effect on the levels of specific cytokines. Interleukin-1 (IL-1) correlated inversely (P less than .02) with age such that the younger the child, the higher the level of IL-1 in MEE. Tumor necrosis factor-alpha (TNF) correlated directly (P less than .005) with age such that the older the child, the higher the level of TNF in MEE. Children undergoing tympanostomy on multiple occasions had average MEE TNF levels (234.2 +/- 109.1 pg/mg total protein) that were nearly 14 times higher (P less than .005) than those from children undergoing their first tympanostomy (16.9 +/- 3.0 pg/mg total protein). Thus IL-1 correlated with the early stages of COME, while TNF correlated with persistence of disease. The presence of these cytokines in MEE may be responsible for the mucosal damage, bone erosion, fibrosis, and resulting hearing loss seen in some cases of COME.

Aging↗
PubMed1991

Otoacoustic emissions in normal and hearing-impaired children and normal adults.

Although distortion-product otoacoustic emissions (DPOEs) have been studied in adults recently, there is little information regarding them in young children. DPOEs and click-evoked otoacoustic emissions (CEOEs) were measured from a same group of normal and hearing-impaired children (age 4 through 10 years) and normal adults (age 22 through 29 years). Measurements of DPOEs in 13 children's ears with normal hearing showed higher levels of emissions in the 700- to 1400-Hz and 5.7-kHz regions relative to the data obtained in 10 normal adult ears. The 22 ears of children with sensorineural hearing loss demonstrated agreement between pure-tone audiograms and "DPOE audiograms." Measurements of CEOEs revealed that the average level of emission in 15 normal-hearing children's ears was slightly lower than that previously obtained in newborns, but slightly higher than that of adults. In children, the CEOE spectral components in the 4- to 6-kHz region were lower than in newborns, but higher than in adults. These results support the view that the DPOEs and CEOEs comprise a valuable tool in assessment of cochlear function in subjects of all ages.

Acoustic Stimulation↗
PubMed1990

Distortion product otoacoustic emissions in normal and impaired adult ears.

Distortion product otoacoustic emissions (DPOEs) were recorded in a group of normally hearing subjects (29 ears) and a group of subjects whose conditions were diagnosed as sensorineural hearing loss (23 ears) to study any correlation that might exist between DPOE characteristics and hearing impairment of different configurations. Three different DPOE paradigms have been used to investigate the influence of different test parameters on the DPOE data for normal and hearing-impaired ears. All normally hearing ears demonstrated detectable DPOEs, provided that the primary tone level was above a certain value. Hearing-impaired ears produced substantially reduced DPOEs compared with normally hearing subjects when the primary frequencies f1 and f2 corresponded to the region of hearing loss. Our data also suggested that, in general, more than one f2/f1 ratio is needed to examine any particular frequency region. The DPOEs provide frequency-specific information about cochlear function, which after further development, may form a basis for a noninvasive, objective method of evaluating cochlear function.

Acoustics↗
PubMed1990

Confirmatory tests for human T-cell leukemia virus type 1 (HTLV-1): western blot compared with RIPA on African sera.

Confirmation of human T-Cell leukemia virus type 1 (HTLV-1) seropositivity calls for reactivity against at least 2 proteins encoded by 2 different genes, revealed by Western blot (WB) and/or radioimmuno-precipitation assay (RIPA). To evaluate the use of WB as a basis for applying these criteria, we conducted a study of two types of WB and compared them with RIPA patterns. The first part of the work, performed with 40 African sera, used Dupont de Nemours commercialized WB and an 'in-house' WB. Both WB detected antibody to proteins encoded by 2 different genes: antibody to gag products were revealed equally by both WB, but commercialized WB detected antibody to tax protein whereas the 'in-house' WB detected antibody to env protein (gp46) more efficiently. The second part of the work, conducted with 158 African sera, compared results of an 'in-house' virus lysate WB and RIPA. Our data show a perfect concordance between the two procedures when sera were clearly positive by WB (gag + env reaction). Sera reacting to p19 and p24 (both gag) by WB were confirmed positive by RIPA in 75% of the cases. The majority of the indeterminate WB profiles not confirmed by RIPA presented isolated gag reactivity (p15 or p19 or p24).

Blotting, Western↗
PubMed1990

Comparison of immunofluorescence, particle agglutination, and enzyme immunoassays for detection of human T-cell leukemia virus type I antibody in African sera.

The effectiveness of four screening tests for detecting antibody to human T-cell leukemia virus type I (HTLV-I) was determined by using 2,700 African serum specimens. The tests studied were indirect immunofluorescence, particle agglutination from Fujirebio, and two enzyme immunoassays, one from Abbott Laboratories that used virus lysate from HUT 102 cells and the other from Cambridge BioScience Corp. that used an env recombinant protein. Positive and doubtful sera were confirmed by Western immunoblot and radioimmunoprecipitation assay with Food and Drug Administration seropositivity criteria. The best results were obtained with the two enzyme immunoassays, which were more sensitive (100 and 98.6% [Abbott and Cambridge, respectively]) and more specific (98.7 and 96.5%). Indirect immunofluorescence exhibited difficulties for reading and interpretation. With particle agglutination, prozone was observed for 9 of 78 HTLV-I-positive serum specimens. False-positives in any of the tests were not linked to cross-reactions with human immunodeficiency viruses. However, confirmation tests remain necessary for HTLV-I screening.

Africa↗
PubMed1990

Pulmonary dirofilariasis: restudy of worms reported gravid.

A worm in the lung of a man in Colombia, whose death was caused by lymphoid leukemia, originally reported as Wuchereria bancrofti with embryos in the uterus, was re-examined and identified as a Dirofilaria sp. and its gravid condition confirmed. A Dirofilaria sp. in the lung of a man in Japan, reported as gravid, was found to be nongravid with sloughed fragments of lining of the uterus mistaken for microfilariae. Noteworthy in the Colombia case is the association of lymphoid leukemia in the host and the gravid condition of the worm.

Adult↗
PubMed1990

The science of caring.

A downsizing crisis at Mount Carmel Medical Center, Columbus, OH, forced its Pastoral Care Department to begin thinking in terms of accountability. Trained in an intuitive style of chaplaincy, the staff distrusted a clinical approach to pastoral care. Nonetheless, when they found themselves scrambling to justify their existence, the entire department staff literally withdrew from the hospital for two days to redesign pastoral care. What evolved was a process of "focused care." It represented a radical departure from their traditional assumptions about chaplaincy in that henceforth they would (1) base their ministry on assessment of spiritual need, with primary attention to high-risk patient populations, (2) continue to provide eucharistic ministry through volunteers, but no longer rely on Catholic chaplains to carry out those duties, (3) no longer assume that a chaplain needed to be present at every death or medical crisis, and (4) no longer assume that the impact of a spiritual ministry could not be objectively measured.

Catholicism↗
PubMed1990

Prevalence of HIV infection among patients with leprosy in African countries and Yemen.

Screening for human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) antibodies was carried out in the serum of 1,245 leprous patients and 5,731 controls selected in nine different centers from the Congo, Ivory Coast, Senegal, and Yemen Arab Republic. In Yemen, all sera were negative. In the Congo, the seropositivity among patients and controls was, respectively, 3.8 and 5.2%; in Senegal, it was 1.3 and 0.6%; and in the Ivory Coast 4.8 and 3.9%. Differences were not statistically significant, even considering lepromatous or tuberculoid forms (3.6% and 3.7%, respectively). HIV-2 antibodies were only detected in subjects from the Ivory Coast and Senegal. Using appropriate criteria for seropositivity (confirmation by Western blot, reactivity to HIV envelope glycoproteins) and a large selection of patients (several countries with several centers), it appears that leprosy (and specially the lepromatous form) is not a factor for HIV infection.

Adolescent↗
PubMed1988

Performance on unimanual and bimanual tapping tasks by patients with lesions of the frontal or temporal lobe.

The performance of 151 patients with unilateral excisions from either the frontal or the temporal cortex and 60 normal subjects was examined on three motor tasks: (1) simple unimanual tapping; (2) spatially ordered unimanual tapping; and (3) bimanual tapping in which the movements of the two hands were out-of-phase. All patient groups were impaired with both hands on spatially ordered unimanual tapping. In contrast, only those patients with either left or right frontal-lobe lesions performed poorly on the bimanual tapping task. Our findings demonstrate that the frontal cortex plays a critical role in the co-ordination of arm and hand movements, particularly when different movements have to be performed simultaneously.

Adolescent↗
PubMed1988

Residual impairment in handgrip strength after unilateral frontal-lobe lesions.

The handgrip strength of 65 normal control subjects and 166 patients with unilateral frontal- or temporal-lobe excisions was assessed. Because of the known sex differences in strength, the results for the men and women were analysed separately. The grip strength of men with left frontal-lobe lesions was found to be within the normal range, but women with comparable excisions from the left frontal lobe had a residual impairment in strength on both hands. The men with right frontal-lobe lesions had a significant reduction in the strength of only the left hand, and the women in this group displayed a similar tendency. The deficits were interpreted in terms of a loss or disruption of input from the premotor area to the primary motor cortex.

Adolescent↗
PubMed1988

Comparison of 10 enzyme immunoassays for detection of antibody to human immunodeficiency virus type 2 in West African sera.

The efficacies of nine enzyme-linked immunosorbent assays (EIA) for antibody to human immunodeficiency virus type 1 (HIV-1) and one EIA for antibody to HIV-2 in detecting antibody to HIV-2 were studied. The competitive EIAs for antibody to HIV-1 were less sensitive than the indirect EIAs. The overall prevalence of positive results was between 28 and 51% with the competitive EIAs and between 70 and 93% with the indirect EIAs. Most of the EIAs were less sensitive in detecting antibody to HIV-2 in sera from people with acquired immunodeficiency syndrome-like diseases than in sera from symptomless individuals. The results indicate that there is a high degree of cross-reactivity between HIV-1 and HIV-2 by EIA, indicating that serotype specificity must be determined by Western blot (immunoblot) with both sets of viral antigens. The results are relevant for discussing public health strategies, especially the screening of blood donors; competitive EIAs for antibody to HIV-1 are not sensitive enough to be used in areas where HIV-2 is prevalent (West Africa).

Antibodies, Viral↗
PubMed1988

Evaluation of olfactory dysfunction in the Connecticut Chemosensory Clinical Research Center.

The olfactory test administered to patients at the Connecticut Chemosensory Clinical Research Center combines stability of outcome with sensitivity to variables known to affect olfaction (age, sex). The test, which pairs an odor threshold component with an odor identification component, readily resolves differences in function between patients and controls. It reveals differences in the distribution of functioning for various probable causes (nasal/sinus disease, postupper respiratory infection, and head trauma), proves sensitive to improvements in function caused by therapeutic intervention (ethmoidectomy, steroid administration for nasal/sinus disease), and correlates with objective signs of nasal/sinus disease (visual exam, x-ray). The two components of the test agree well, though the odor identification component seems somewhat more sensitive than the threshold component as currently designed.

Adolescent↗