Biomedical subjects

K E Smith

Publications and source records attributed to K E Smith.

At least 91 records · Page 5Linked to original sources

PubMed1996

Thermus oshimai sp. nov., isolated from hot springs in Portugal, Iceland, and the Azores, and comment on the concept of a limited geographical distribution of Thermus species.

We examined aerobic, thermophilic, gram-negative bacteria that were isolated from hot springs in Portugal and were identified as Thermus strains and placed in phenetic groups on the basis of their phenotypic characteristics. We determined the composition of the peptidoglycan, identified the respiratory quinones, and determined the mean base composition of the DNA, and the levels of DNA-DNA homology were determined by both the filter hybridization and reassociation rate methods. Thermus aquaticus, Thermus brockianus, and Thermus filiformis were not detected in this collection of organisms, although three Thermus thermophilus strains were identified. We propose that the isolates that belonged to phenetic clusters E and F are members of a new species, Thermus oshimai; the type strain of T. oshimai is strain SPS17.

Azores↗

PubMed1996

Colour discrimination by the sheep blowfly Lucilia sericata.

In laboratory trials designed to examine the alighting response of the blowfly Lucilia sericata Meigen to colour, yellow sticky cloth targets caught the largest number of both males and females, followed by pale blue, black, green, dark blue and red. The number caught by any colour showed a strong positive relationship with the percentage of its spectral reflectivity in the 450-580 nm wavelength band. In field trials, targets baited with the synthetic attractant "swormlure' caught significantly fewer L.sericata than targets baited with liver and sodium sulphide, suggesting that the former bait is a relatively poor attractant for this species, at the release rates used in the present study. However, there was no effect of target colour on catch, neither was there any interaction between colour and odour bait type. The results, from both the laboratory and field trials, suggest that the strength of responses by L.sericata to visual cues are weak relative to responses to odour. Responses to hue are readily overridden by a range of factors such as brightness and contrast with the background and are therefore likely to be difficult to detect or manipulate reliably in trapping systems in the field.

Animals↗

PubMed1996

The relation of medical risk and maternal stimulation with preterm infants' development of cognitive, language and daily living skills.

High-risk (HR) and low-risk (LR) preterm infants (N = 212) and full-term infants (FT, N = 128) from low socio-economic homes were studied with their mothers in the home at 6 and 12 months of age. Infants' cognitive, language and daily living skills were evaluated in relation to mothers' warm sensitivity, use of strategies which maintained the infants' attention and directiveness. Higher levels of maternal attention-maintaining were positively related to infant development for all groups. During toy play, attention-maintaining was most strongly related to expressive language skills for the HR infants; during toy play and daily activities, this maternal behavior was more strongly related to cognitive and language skills for both preterm groups than for the FT infants.

Activities of Daily Living↗

PubMed1996

Residual-limb shape change: three-dimensional CT scan measurement and depiction in vivo.

PURPOSE: To perform quantitative evaluation of lower-extremity prosthesis fit by using spiral computed tomography (CT). MATERIALS AND METHODS: Two spiral CT scans were obtained at each of two different sessions in seven adult patients who had undergone amputation below the knee. A rigid-body transformation of the tibia was computed and used to align paired (intra- and intersession) spiral CT data sets for each individual in a common coordinate system. Paired scans in each individual were compared to assess registration and precision of soft-tissue change measurement. Clinical prosthesis fit evaluation was demonstrated in an adult amputee volunteer who underwent CT evaluation while wearing two different prostheses. RESULTS: In the seven patients examined, more than 90% of the measured soft-tissue volume displacements between sessions could be explained as true differences. Precision error of soft-tissue volume change was approximately 13 cm3, or approximately 1% error relative to the mean volume. Volumetric changes due to different prostheses were substantially larger than the random error. CONCLUSION: Registration of CT volumetric data sets to quantify residual-limb soft-tissue envelope change in lower-limb prosthetics is precise and can be used to detect the effect of prosthesis shape alterations.

Adult↗

PubMed1996

Severity of medical and neurologic complications as a determinant of neurodevelopmental outcome at 6 and 12 months in very low birth weight infants.

Very low birth weight (n = 154) and term infants (n = 119) had neurologic and developmental assessment at 6 and 12 months of age. Preterm infants with severe neonatal complications were considered to be at high risk, and those with milder complications were considered to be at low risk, for neurodevelopmental abnormality. Compared to term infants, high- and low-risk infants had abnormalities at 6 months in total neurologic score, cranial nerves, motor tone, motor coordination, and reflexes (P < .001). At 12 months, all groups had improved. However, high-risk infants had persistent abnormalities in the same subcategories (P < .001), whereas low-risk infants differed from term infants only in motor tone (P < .001). Bayley developmental scores were different for all groups at 6 months (P < .001), but at 12 months only high-risk infants differed from term infants (P < .01). These results demonstrate improvement in neurologic and developmental scores over time in very low birth weight infants. The degree of neurodevelopmental abnormality and improvement over time is related to severity of neonatal complications in preterm infants.

Age Factors↗

PubMed1996

Monitoring of Culicoides spp. at a site enzootic for hemorrhagic disease in white-tailed deer in Georgia, USA.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) were monitored at a Georgia (USA) site where epizootic hemorrhagic disease (EHD) and bluetongue (BT) viruses are enzootic among white-tailed deer (Odocoileus virginianus). Collections were made using a captive white-tailed deer and light traps from June 1993 through November 1994. We collected 210,482 females from the captive deer during morning and evening periods. Predominant species were C. lahillei (73%), C. stellifer (16%), C. biguttatus (6%), C. niger (3%), C. spinosus (2%), and C. paraensis (0.2%). Other species were C. venustus, C. obsoletus/sanguisuga, C. haematopotus, C. guttipennis, and C. arboricola, which together represented < 0.1% of the specimens collected. No C. variipennis, a known vector of EHD and BT viruses, were collected from the deer. An estimated 953,299 females were collected in 695 light-trap nights. The most common species in light-trap collections were C. spinosus (45%), C. biguttatus (27%) and C. stellifer (24%). Culicoides variipennis was rare in the light-trap samples, representing < 0.01% of the total collections. There was serological evidence from hunter-killed deer that local deer were infected with EHD and BT viruses during the study, particularly during 1994. A primary suspect vector was C. lahillei, which attacked the bait deer in large numbers during the summer and early fall of both 1993 and 1994. Based on their seasonality, relative abundance, and host-seeking activity, C. stellifer and C. spinosus also were considered as possible vectors. However, virus isolation attempts on 113,716 Culicoides, including 62,530 C. lahillei and 32,769 C. stellifer, were negative.

Animals↗

PubMed1996

Hemorrhagic disease in white-tailed deer in Texas: a case for enzootic stability.

Although antibodies to viruses in both the epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV) sero-groups have been reported from white-tailed deer (Odocoileus virginianus) in Texas (USA), there are few reports of hemorrhagic disease (HD) in these populations. To understand the extent and diversity of exposure to the North American EHDV and BTV serotypes in these deer populations, we serologically tested 685 white-tailed deer collected from November 1991 through March 1992 throughout their range in Texas. Overall, 574 (84%) of deer had antibodies to EHDV or BTV. Prevalence estimates varied according to ecological region, from 57% in the Gulf Prairies to 100% in the northwest Edwards Plateau. Based on serum neutralization tests, the deer had evidence of previous exposures to multiple EHDV and BTV serotypes, with evidence of exposure to two to five serotypes detected in each ecological region. The apparent lack of HD in relation to this high antibody prevalence cannot be explained, but may be related to enzootic stability in which a near perfect host-virus relationship exists.

Age Distribution↗

PubMed1996

Design of a 3-D surface scanner for lower limb prosthetics: a technical note.

A three-dimensional (3-D) noncontact optical surface range sensing imaging system that captures the entire circumferential and distal end surfaces of lower limb residua in less than 1 second has been developed. The optical surface scanner (OSS) consists of four charge injection device (CID) cameras and three white light projectors, mounted on a rigid frame surrounding the subject's residuum, allowing 360 degrees surface coverage of the lower residual limb. Anatomic 3-D computer graphics reconstruction of a residuum surface, recorded with the OSS imaging system, is used for visualization and measurement. One cubical and two spherical calibration test objects were used to obtain a system precision of less than 1 mm. In a study conducted with 13 persons with below knee (BK) amputation, the OSS system was compared to calipers, electromagnetic digitizer, and volumetric computed tomography with better than 1 mm precision on plaster positive casts and approximately 2 mm on the residual limbs.

Amputation, Surgical↗

PubMed1995

Interactions between the GroE chaperonins and rhodanese. Multiple intermediates and release and rebinding.

Efficient renaturation of urea-denatured rhodanese using the chaperonin GroE system requires GroEL, GroES, and ATP. At high concentrations this renaturation also requires the substrate thiosulfate to have been present during GroEL-rhodanese complex formation. When thiosulfate is present the GroEL-rhodanese complex can be concentrated to greater than 1 mg/ml rhodanese with little effect on the efficiency of renaturation. However, if complex is formed in the absence of thiosulfate, renaturation of rhodanese in the presence of thiosulfate shows a critical concentration of approximately 0.4 mg/ml, above which renaturation yields drop dramatically. This critical concentration appears to be related to an aggregation event in the refolding of rhodanese. The nucleotide free or ADP-bound form of GroEL also binds to rhodanese that has been either already renatured or never denatured. The bound rhodanese has no activity but can be released from GroEL with ATP recovering 90% of control activity. The data presented herein support a release and rebinding mechanism for the GroE-assisted refolding of rhodanese. It also suggests GroEL binds several protein folding intermediates along the entire refolding pathway.

Adenosine Diphosphate↗

PubMed1995

Molecular cloning of an orphan transporter. A new member of the neurotransmitter transporter family.

A complementary DNA clone predicted to encode a novel transporter was isolated from rat brain and the localization of its mRNA was examined. The cDNA, designated rB21a, predicts a protein with 12 putative transmembrane domains that exhibits significant sequence homology with neurotransmitter transporters. Expression studies have not yet identified the endogenous substrate for this transporter, but the presence of rB21a mRNA within the leptomeninges of the brain suggests the transporter may regulate CSF levels of its substrate. The cloning of rB21a provides the means to determine its physiological functions and the potential to design novel, transporter-based therapeutic agents for neurological and psychiatric disorders.

Amino Acid Transport Systems, Neutral↗

PubMed1995

Assessment of mass properties of human head using various three-dimensional imaging modalities.

Better methods are needed to analyse personal protective devices, such as helmets or facemasks, before they are used in practice. Software tools to quantify three-dimensional craniofacial mass properties are developed to improve our understanding of craniofacial impact biomechanics, supplement existing knowledge of osseous structure and provide a comprehensive description of human head morphology. The application of state-of-the-art imaging systems, solid modelling and other software tools are studied to determine the associated errors in mass property estimation by spiral computed tomography, three-dimensional magnetic resonance and optical surface scanning using phantoms and cadaver head studies. Volume, centre of gravity and principal moments of inertia are determined from solid mathematical models for each scanning modality. Landmark-based registration is used to register scans of the same object obtained from the three imaging modalities to a common reference co-ordinate system. Physically and analytically determined mass properties are used as the standard for truth. Although this comparative study does not lend itself to statistical analysis owing to the small sample size, results indicate that any of the three imaging modalities can be used to predict mass properties within the uncertainty of existing methods. Applying these techniques in vivo is practical and feasible.

Cephalometry↗

PubMed1995

Localization of messenger RNAs encoding three GABA transporters in rat brain: an in situ hybridization study.

Localization of the messenger RNAs encoding three gamma-aminobutyric acid (GABA) transporters, termed GAT-1, GAT-2, and GAT-3, has been carried out in rat brain using radiolabeled oligonucleotide probes and in situ hybridization histochemistry. Hybridization signals for GAT-1 mRNA were observed over many regions of the rat brain, including the retina, olfactory bulb, neocortex, ventral pallidum, hippocampus, and cerebellum. At the microscopic level, this signal appeared to be restricted to neuronal profiles, and the overall distribution of GAT-1 mRNA closely paralleled that seen in other studies with antibodies to GABA. Areas containing hybridization signals for GAT-3 mRNA included the retina, olfactory bulb, subfornical organ, hypothalamus, midline thalamus, and brainstem. In some regions, the hybridization signal for GAT-3 seemed to be preferentially distributed over glial cells, although hybridization signals were also observed over neurons, particularly in the retina and olfactory bulb. Notably, hybridization signal for GAT-3 mRNA was absent from the neocortex and cerebellar cortex, and was very weak in the hippocampus. In contrast to the parenchymal localization obtained for GAT-1 and GAT-3 mRNAs, hybridization signals for GAT-2 mRNA were found only over the leptomeninges (pia and arachnoid). The differential distribution of the three GABA transporters described here suggests that while each plays a role in GABA uptake, they do so via distinct cellular populations.

Animals↗

PubMed1995

Microbial transformation of steroids--IX. Purification of progesterone hydroxylase cytochrome P-450 from Phycomyces blakesleeanus.

Progesterone hydroxylase cytochrome P-450 was purified to homogeneity from Phycomyces blakesleeanus microsomes by a four step procedure. An M(r) value of 60,000 was determined for this protein by SDS-PAGE. The DEAE-cellulose and Blue-1 MIMETIC affinity fractions gave major peaks at 452 nm in a dithionite-reduced, carbon monoxide, difference spectrum. NaIO4-dependent progesterone hydroxylation was obtained by the pure enzyme without NADPH and NADPH-cytochrome P-450 reductase. NADPH-dependent hydroxylation required the addition of other Phycomyces microsomal proteins present in the Blue-1 fraction.

Chromatography, Affinity↗

PubMed1995

Cloning and expression of a betaine/GABA transporter from human brain.

A cDNA clone encoding a human gamma-aminobutyric acid (GABA) transporter has been isolated from a brain cDNA library, and its functional properties have been examined in mammalian cells. The nucleotide sequence predicts a transporter with 614 amino acids and 12 putative transmembrane domains. The highest degree of amino acid identity is with a betaine/GABA transporter originally cloned from the dog termed BGT-1 (91%) and a related transporter from mouse brain (87%). These identities are similar to those for species homologues of other neurotransmitter transporters and suggest that the new clone represents the human homologue of BGT-1. The transporter displays high affinity for GABA (IC50 of 30 microM) and is also sensitive to phloretin, L-2,4-diaminobutyric acid, and hypotaurine (IC50 values of approximately 150-400 microM). The osmolyte betaine is approximately 25-fold weaker than GABA, displaying an IC50 of approximately 1 mM. The relative potencies of these inhibitors at human BGT-1 differ from those of mouse and dog BGT-1. Northern blot analysis reveals that BGT-1 mRNA is widely distributed throughout the human brain. The cloning of the human homologue of BGT-1 will further our understanding of the roles of GABA and betaine in neural function.

Amino Acid Sequence↗

PubMed1995

DNA relatedness of Thermus strains, description of Thermus brockianus sp. nov., and proposal to reestablish Thermus thermophilus (Oshima and Imahori)

Aerobic, thermophilic, gram-negative bacteria obtained from Yellowstone National Park that were placed in the genus Thermus on the basis of phenotypic data were examined by chemotaxonomic techniques to determine their peptidoglycan compositions, their respiratory quinones, their mean DNA base compositions, and their levels of DNA-DNA homology as determined by both the filter hybridization and reassociation rate methods. These isolates from hot springs included Thermus aquaticus strains and strains of a new genospecies. We propose the name Thermus brockianus for this new genospecies; strain YS38 is the type strain of this taxon. A collection of 10 strains, including the type strain of "Thermus thermophilus", which were isolated from widely separated geothermal sites, exhibited high levels of DNA-DNA homology with each other and had similar physiological properties. Therefore, we propose that the species Thermus thermophilus (Oshima and Imahori) should be reestablished, with strain HB8 as the type strain.

Base Composition↗

PubMed1995

Validation of spiral CT and optical surface scanning for lower limb stump volumetry.

Spiral X-ray Computed Tomography (SXCT), Optical Surface Scanning (OSS), and hydrostatic weighing methods were used to measure stump volume of trans-tibial amputees. The precision and accuracy of these methods were assessed in a validation study. A repeated measures analysis of variance statistical design was employed that required each participant to be measured (scanned) twice at each of two separate measurement sessions. For OSS and SXCT, each scan was segmented twice to determine intra-observer error. Plaster cast replicas of subject stumps were formed by certified prosthetists to serve as a reference standard. Accuracy (bias) of SXCT and OSS was determined by comparison to volumetry by hydrostatic weighing. Ten trans-tibial amputees were recruited for this study and nine completed both sessions. Plaster replica measurement precision error relative to the mean was found to be less than 1% for all modalities. The precision was slightly inferior on subjects, 1.1% and 2.2% error for hydrostatic weighting and OSS respectively, due to patient instability during measurement, but was better with SXCT where the subjects' stumps were stabilized during scan acquisition. The OSS and SXCT methods offer advantages over hydrostatic weighing and other volumetry methods since the volume data are represented digitally and can be analyzed in multiple ways. SXCT enables study of the stump and its internal tissues with the prosthesis in place. It was found that SXCT is comparable to hydrostatic weighing in both precision and accuracy. While OSS had a high precision and reproducibility, it was found to have an associated bias.

Adult↗

PubMed1995

Toxoplasmosis in a bobcat (Felis rufus).

A bobcat (Felis rufus) estimated to be 6-mo old exhibited head pressing, stupor, intermittent seizures, and vocalization. Based on gross and histopathologic features, it was diagnosed to have severe focally extensive protozoal meningoencephalitis. Toxoplasma gondii was confirmed as the etiologic agent by an avidin-biotin immunohistochemical test. This is the first report of clinical toxoplasmosis in a free-ranging bobcat.

Animals↗

PubMed1995

Stopping the burn.

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Accidents, Occupational↗