Neuroscience. Information coding.
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Action Potentials↗
Biomedical subjects
B Richmond
Publications and source records attributed to B Richmond.
Testing the taxonomic integrity of Paranthropus boisei sensu stricto.
The craniodental hypodigm of Paranthropus boisei sensu stricto is morphologically distinctive, but it has been suggested that the substantial variation in mandibular and dental size in that hypodigm may exceed that which is reasonable to subsume within a single hominin species. In this study, Fligner and Killeen, coefficient of variation (CV)-based and average taxonomic distance (ATD)-based bootstrap tests, were used to compare variation in size and shape of the mandibular corpus remains attributed to P. boisei s.s. with the variation observed in samples of great apes and modern humans. The degree of size variation in the P. boisei s.s. mandibular hypodigm is never observed in human and chimpanzee samples, is rare in gorillas, but is not uncommon in orangutans. However, the shape variation in the fossil group is comparable to the variation in the extant reference groups. Although the size variation in P. boisei s.s. is substantial, it is exaggerated by the effects of taphonomy. The small mandibles are more often abraded, whereas the large mandibles are more likely to have been infiltrated with matrix. On the basis of the results of this investigation of the mandibular corpus, there are no grounds for rejecting the "single-species" hypothesis for P. boisei s.s. When Sokal and Braumann's adjusted CV values were used to predict the index of sexual dimorphism (ISD) for the P. boisei s.s., despite the substantial geological time embraced by the mandibular corpus hypodigm, the predicted value of lnISD, when corrected for taphonomic factors, is comparable to the sexual dimorphism observed within Gorilla.
Animals↗
Image distribution in a multi-facility radiology practice.
The Cleveland Clinic Health System is a multifacility practice that distributes images electronically. Issues specific to the internal department at the main campus must be addressed with regard to the overall commitment to the healthcare system. Training for new and old employees on diagnostic and transcription equipment is a key issue. Interfacing different systems or different configurations of a system, either hospital or radiology information systems, is many times difficult and sometimes insurmountable. Issues of confidentiality have been addressed. In light of the impending new regulations from the Health Insurance Portability and Accountability Act, are the current system security practices enough?
Humans↗
Unusual facet cyst containing struvite and hydroxyapatite.
This case report describes a patient with severe back pain and radiculopathy. She was found to have a facet cyst within the lumbar spine that appeared to contain calcium on MRI and CT. Upon aspiration the cyst was found to contain calcium ammonium phosphate (struvite) and calcium phosphate (hydroxyapatite). Ammonia production in the presence of urease-producing bacteria is responsible for the production of struvite in the human body. We postulate that there was a prior infection of the facet with urease-producing bacteria, thus accounting for the production of the struvite within the facet cyst.
Durapatite↗
Integrated diagnostic workstation.
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Computer Communication Networks↗
How well can we estimate the information carried in neuronal responses from limited samples?
It is difficult to extract the information carried by neuronal responses about a set of stimuli because limited data samples result in biased estimates. Recently two improved procedures have been developed to calculate information from experimental results: a binning-and-correcting procedure and a neural network procedure. We have used data produced from a model of the spatiotemporal receptive fields of parvocellular and magnocellular lateral geniculate neurons to study the performance of these methods as a function of the number of trials used. Both procedures yield accurate results for one-dimensional neuronal codes. They can also be used to produce a reasonable estimate of the extra information in a three-dimensional code, in this instance, within 0.05-0.1 bit of the asymptotically calculated value--about 10% of the total transmitted information. We believe that this performance is much more accurate than previous procedures.
Computer Simulation↗
Implementation of an electronic teaching file using web technology.
The implementation of an electronic teaching file using web technology is discussed in this article. A web client server model is used for a standard web browser capable of displaying joint photographic Experts Group (JPEG) compression images. Like other web-based teaching files, this teaching file in a similar way uses a database containing information. This database section of the teaching file allows flexible database querying and viewing of pages generated by hypertext markup language (HTML). Because the browser client is so flexible, images types such as video and 3D representations with virtual reality markup language (VRML) can be displayed.
Computer Communication Networks↗
Activated microglia are the principal glial source of thromboxane in the central nervous system.
Thromboxane A2(TxA2) is a potent vasoconstrictor associated with cerebrovascular disease and is thought to be synthesized within tissues of the brain. In order to determine the cellular sources of TxA2 in the central nervous system (CNS), we measured the release of the stable metabolite TxB2 in cultures of mixed or highly enriched populations of brain glia. Using techniques which isolated large numbers of highly enriched microglia and astroglia, we found that only microglia release TxB2. Moreover, microglia, not astroglia, contain the requisite synthetic enzyme thromboxane synthase. Phagocytic signals and lipopolysaccharide are potent stimulants of microglial release of thromboxane, with lesser effects shown by platelet activating factor and substance P. We conclude that microglia, when activated, are the principal source of brain-derived thromboxane and may help to control vascular flow at sites of acute CNS injury.
Animals↗
Wheelchair wash day.
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Anniversaries and Special Events↗
Radiology image interpretation system: modified observer performance study of an image interpretation expert system.
Application of computer-based expert systems to diagnostic medical problems has been described in many areas including clinical diagnosis and radiology. Expert systems are computer programs that contain encoded expert knowledge to provide expert advice. A modified observer-performance study was done comparing the efficacy of the Radiology Image Interpretation System (RIIS), an expert system that diagnoses focal bone abnormalities, and radiology residents on a known set of 44 abnormal and 10 normal cases. Modified receiver operating characteristic curves for four inexperienced residents, five experienced residents, and RIIS were generated using the set of known radiographs. The true-positive rates of RIIS and the residents at false-positive rates of 0.05, 0.15, and 0.20 were estimated using the modified receiver operating characteristics curve and were compared using a paired t test. On the average, the RIIS system was less accurate when compared with experienced and inexperienced residents but the difference was only significant for experienced residents at a false-positive rate of 0.05. RIIS performed better than inexperienced residents when RIIS was used by experienced residents but this difference was not significant.
Bone Diseases↗
Total knee replacement: radiologic findings in failure of porous-coated metal-backed patellar component.
One technique for replacing the articular surface of the patella in total knee replacement is the use of a cementless porous-coated metal-backed polyethylene component. Anteroposterior, lateral, and Merchant or skyline radiographs in 10 cases of porous-coated metal-backed components that failed were evaluated for component alignment, component displacement, radiolucencies, loose beads, and integrity of the patellar component. Component failure was documented by surgery in all 10 cases. Seven cases of failure involved the patellar pegs or junction of the pegs with the metal backing and three cases involved the polyethylene portion. In the seven cases of peg-metal backing failure, three cases showed loose beads before failure and seven cases showed displacement of the metal backing at time of failure. All three cases of polyethylene failure showed narrowing or displacement of the polyethylene portion. Our experience shows that displacement of the metal backing, displacement of the polyethylene, and disruption of patellar pegs are seen in failed porous-coated metal-backed patellar components. Loose beads may be seen before peg-metal backing failure.
Humans↗
Bone quality. Roentgenographic versus histologic assessment of hip bone structure.
Bone quality is an accepted criterion for determining fixation options for total hip arthroplasty (THA). Eighty patients with 95 uncemented THAs were evaluated by comparing preoperative roentgenographic assessment with histologic evaluation of bone biopsy specimens obtained from the ipsilateral iliac crest. Roentgenographic analysis of bone quality was performed using the Singh and Engh indices. Histologic evaluation employed a quantitative analysis of static and dynamic parameters of bone turnover on undecalcified sections. Extensive statistical analysis comparing roentgenographic with histologic parameters of bone quality showed: (1) no relationship of the two roentgenographic indices to trabecular bone volume and most other histologic parameters and (2) a high incidence of bone abnormalities. Bone quality is an imprecise term and is inadequately measured by these roentgenographic indices. Histologic measurement offers a more precise means of analyzing the relationship of the bone environment to the performance of the THA.
Biopsy↗
Hepatobiliary imaging to demonstrate drainage patterns in a patient with an indwelling hepatic catheter.
The presence of normal biliary flow was established in a patient with an indwelling hepatic catheter placed to drain an intrahepatic cyst cavity with the use of sequential hepatobiliary scintiscans. In the initial study drainage was demonstrated from the indwelling catheter; when the catheter was clamped, drainage was observed in the native biliary system. Serial biliary scintigraphy not only confirmed the patency of the hepatobiliary system, but served as a guide in the removal of the intrahepatic catheter.
Catheters, Indwelling↗
Noninvasive testicular screening in childhood leukemia.
To evaluate the potential of transscrotal ultrasound and magnetic resonance imaging as noninvasive screening methods we studied 8 boys with acute lymphocytic leukemia before testicular biopsy. Ultrasonic images of the testes were performed in 4 patients, including 2 with negative and 2 with positive biopsies, and all images were interpreted as normal. Magnetic resonance images of the testes also were interpreted as normal in 4 patients, including 2 with negative and 2 with positive biopsies, and they were technically inadequate in the remaining 4. The results suggest that neither transscrotal ultrasonography nor magnetic resonance imaging as currently applied may substitute reliably for testicular biopsy as a screen for occult testicular leukemia.
Adolescent↗
The appearance of a large mesenteric varix on a technetium-99m red blood cell gastrointestinal bleeding study.
Detection of gastrointestinal bleeding using Tc-99m labeled RBCs has proven to be clinically useful although false-positive images associated with abnormal vascularity remain problematic. The scintigraphic appearance of a large mesenteric varix is presented, and its potential confusion with gastrointestinal bleeding is discussed. Correlative CT and angiographic images are presented.
Angiography↗
Cerebral venous angiomas.
Several unusual cases of cerebral venous angiomas as well as some characteristic cases are reported. The characteristic angiographic feature is that of a collection of dilated medullary veins draining into a single large draining vein, which appears first in the early venous phase and persists into the late venous phase of the arteriogram. Computed tomography (CT) was abnormal in 12/13 cases. The draining vein was the most common abnormality identified on CT. Coronal and sagittal reconstruction may be helpful in demonstrating the draining vein. A case of large twin venous angiomas, a case of hemorrhage from a venous angioma, and a case of a venous angioma with an incidentally associated glioblastoma are presented.
Adolescent↗
Substrate effect on 2,3-butylene glycol production by Rhizopus nigricans and Penicillium expansum.
Rhizopus nigricans and Penicillium expansum produced 2,3-butylene glycol which accumulated in natural and artificial media with time. Mycelial mats of P. expansum decreased the quantity of a diacetyl substrate and converted part of this substrate into acetylmethylcarbinol (AMC) and 2,3-butylene glycol. Mycelial mats of P. expansum also decreased AMC substrate with the formation of 2,3-butylene glycol. 2,3-Butylene glycol decreased slightly during incubation with the fungal mat. The formation of AMC was suppressed significantly by cysteine and ascorbic acid.
1-Propanol↗
Distribution of thermophilic aerobic sporeforming bacteria in food ingredients.
Samples of sugar, starch, spices, and miscellaneous products were tested for thermophilic sporeformers of Bacillus to determine the dominant species present. Surface colonies selected at random were identified. Six species of Bacillus were isolated: B. stearothermophilus, B. coagulans, B. licheniformis, B. subtilis, B. circulans, and B. pumilus. Samples of starch and pepper were tested for thermophilic sporeformers of Bacillus to determine the distribution of rough and smooth variants. Colonies were classified as rough or smooth variants by colonial characteristics. The distribution of variant forms in these two products was significantly different. Starch samples showed predominantly rough variants; pepper samples showed predominantly smooth variants.
Bacillus↗