Biomedical subjects

G Bedi

Publications and source records attributed to G Bedi.

8 recordsLinked to original sources

PubMed2002

Design and validation of a surrogate humerus for biomechanical testing.

At present biomechanical testing of fracture plating strategies is conducted using animal or cadaveric whole bone models. This may introduce experimental error into these studies. This communication summarises the design and validation of a novel bone and fibre-reinforced plastic construct conceived to minimise intra-experimental error. A tubular surrogate humerus was produced with dimension and strength matched to that of the human humerus. Bone inserts placed into the wall of the tube allow for the fixation of the plates with bone screws. Three-point bending tests of the flexural rigidity of the surrogate humerus (EI=100.1 (SD 6.0)Nm(2)) showed it to be comparable to the human humerus. Further, pull-out tests of the screws showed that the bone slots adequately mimicked the whole bone scenario. This testing construct will be used for a comparative study of humeral plating techniques.

Animals↗

PubMed2000

The reliability of the American Knee Society Score.

We have investigated the reliability of the American Knee Society Score (AKS), a widely used functional outcome score for knee arthroplasty. 29 subjects were assessed in random order by 6 observers, each patient seen twice by each observer. The interobserver reference intervals were 16 points for the Knee Score (0-100 points) and 21 points for the Function Score (0-100 points). The intraobserver reference intervals were smaller, 11 points and 13 points for the Knee Score and the Function Score, respectively. The presence of arthritis in other joints and general debility did not affect the reliability of the scores. The more experienced observers had greater intraobserver reproducibility. Notably, we found moderate agreement between observers in the subjective variables, while the objective variables produced lower levels of agreement. The high inter- and intraobserver variations of the AKS makes estimation of score change questionable. Reliable use of the AKS would necessitate repeated evaluation by an experienced observer.

Arthroplasty, Replacement, Knee↗

PubMed1996

Language comprehension in language-learning impaired children improved with acoustically modified speech.

A speech processing algorithm was developed to create more salient versions of the rapidly changing elements in the acoustic waveform of speech that have been shown to be deficiently processed by language-learning impaired (LLI) children. LLI children received extensive daily training, over a 4-week period, with listening exercises in which all speech was translated into this synthetic form. They also received daily training with computer "games" designed to adaptively drive improvements in temporal processing thresholds. Significant improvements in speech discrimination and language comprehension abilities were demonstrated in two independent groups of LLI children.

Algorithms↗

PubMed1995

A novel p16INK4A transcript.

p16INK4A and p15INK4B were initially identified as potent inhibitors of activated cyclin/cyclin-dependent kinase complexes. These genes were colocalized to chromosome 9p21, and p16 was subsequently found to be mutated in familial melanoma and deleted in a wide variety of sporadic cancers. We recently found that de novo methylation of a 5' CpG island led to transcriptional block of full-length p16 in many neoplasms. However, the presence of a truncated p16 transcript in methylated cell lines led us to investigate the presence of an alternative promoter or initiation site. We have now identified an abundant alternative p16 transcript in both methylated and unmethylated cell lines generated from a novel sequence (exon 1 beta) potentially involved in the complex regulation of these critical cell cycle genes.

Base Sequence↗

PubMed1995

Impulsivity and the initiation of fights in children with disruptive behavior disorders.

This study examined whether children who initiate physical fights are impulsive as measured by a continuous performance test. A series of 111 7-13-year-old psychiatric patients were diagnosed using DSM-III-R criteria and divided according to whether they showed a persistent pattern of initiating physical fights. Children who initiated fights were impulsive irrespective of whether ADHD was present or not, although ADHD was also associated with increased impulsivity. Oppositional-defiant disorder and conduct disorder diagnoses were not associated with impulsivity. These findings are discussed in terms of an underlying impulsive personality trait and its possible relationship to outcome in children with disruptive behavior disorders.

Adult↗

PubMed1995

AIDS-related Kaposi's sarcoma is a clonal neoplasm.

Kaposi's sarcoma is generally believed to be a non-neoplastic hyperproliferation because it may regress spontaneously and its spindle cells lack features of typical tumor cells, such as aneuploidy, nuclear atypia, and permissive growth in cell culture. A fundamental characteristic of neoplasms is clonality, in that they arise from clonal replication of a single cell whereas reactive processes are derived from polyclonal proliferation. We used an X chromosome inactivation assay to determine the clonality of Kaposi's sarcoma nodules from patients with AIDS-related disease. The assay is based on a methyl-sensitive restriction digest followed by PCR amplification of the highly polymorphic androgen receptor gene. Two of three evaluable cases had a monoclonal pattern of inactivation, and the third case had a clonal expansion of cells with an altered microsatellite repeat sequence. These data suggest that Kaposi's sarcoma (at least in the AIDS setting) is a clonal neoplasm.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Specificity of inattention, impulsivity, and hyperactivity to the diagnosis of attention-deficit hyperactivity disorder.

Children with attention-deficit hyperactivity disorder (ADHD) were compared with non-ADHD psychiatric patients and normal controls on objective measures of inattention, impulsivity, and hyperactivity to determine the specificity of these symptoms to ADHD. Inattention and impulsivity were assessed using a continuous performance test, and activity was measured using solid state actigraphs. Both patient groups were inattentive relative to normals, but were indistinguishable from each other. However, the ADHD group was more active than both non-ADHD patients and normals, who did not differ from each other. These data suggest that inattention may be a nonspecific symptom of child psychiatric disorder. However, ADHD may be uniquely characterized by overactivity.

Adolescent↗

PubMed1991

Periodontal bone level and gingival proteinase activity in gnotobiotic rats immunized with Bacteroides gingivalis.

Bacteroides gingivalis is associated with various forms of periodontal disease. To assess the role of the immune response in modulating B. gingivalis-associated periodontal disease, the effect of immunization of B. gingivalis-induced periodontal bone loss was evaluated in gnotobiotic rats. Male Sprague-Dawley rats immunized with various doses of whole cells or sham-immunized with incomplete Freund's adjuvant were monoinfected with B. gingivalis in carboxymethylcellulose by gavage. Two additional groups served as either sham-immunized or untreated germ-free controls. Forty-two days after infection, all rats were killed, periodontal bone level was assessed morphometrically and radiographically, and gingival proteinase (mammalian collagenase and acid cathepsin) activity was assessed biochemically. B. gingivalis was present in oral samples from all monoinfected rats, and no contaminating bacteria were detected in any oral or fecal sample. Animals immunized with B. gingivalis cells had elevated serum and saliva antibodies to whole cells and partially purified fimbriae from B. gingivalis. Infected sham-immunized rats had significantly more periodontal bone loss than noninfected controls, whereas the periodontal bone level in infected rats immunized with 10(10) B. gingivalis cells was similar to that of the noninfected controls. The activities of gingival collagenase and cathepsin B and L were high in sham-immunized infected rats and low in all other animal groups. In conclusion, it is possible to reduce B. gingivalis-induced periodontal tissue loss in gnotobiotic rats by immunization.

Alveolar Bone Loss↗