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Biomedical subjects

J Comerford

Publications and source records attributed to J Comerford.

10 recordsLinked to original sources
PubMed2000

The dynamics of concussive head impacts in rugby and Australian rules football.

A study was commenced in 1998 at the University of New South Wales (UNSW) to investigate the dynamics of head impacts in football which resulted in concussion. Sixty-eight cases of medically verified concussion from Australian Rules Football and 32 from Rugby Union and Rugby League were analyzed. Video of each injury event was analyzed to obtain descriptive data regarding the head impact site and striking object. The video was analyzed quantitatively to obtain estimates of the closing speeds. A secondary analysis was undertaken using the conservation of momentum and energy relationships to estimate the change in velocity of the head during the impact, the change in momentum of the head, and the energy imparted to the head. Ninety-seven cases involved direct head contact, whereas three cases involved impulsive loading via the trunk. The majority of impacts were to the tempero-parietal region, and the striking body segment was commonly the arm or shoulder/thorax. The mean change in velocity of the head and head impact energy for all 97 cases of direct head impact were 4 m x s(-1) and 56 J, respectively. Head impact energy can be used as a performance criteria for testing and developing headgear for rugby and Australian rules football.

Athletic Injuries↗
PubMed1995

Comparison of PCR with southern hybridization for the routine detection of immunoglobulin heavy chain gene rearrangements.

The development of a reliable polymerase chain reaction (PCR) technique for the routine detection of clonal immunoglobulin heavy chain (IgH) gene rearrangements would represent an attractive alternative to Southern hybridization analysis because of the relative simplicity of PCR protocols, and because the requirements for both quality and quantity of DNA would be considerably less stringent. To assess the utility of PCR for the routine detection of clonal IgH gene rearrangements, samples from 123 adult patients were evaluated and analysis by PCR amplification using IgH Framework 1 or Framework 3 variable region consensus primers was compared with analysis by restriction endonuclease digestion and Southern hybridization with genomic, IgH probes. The authors found that 90% of IgH genes found to be rearranged by Southern hybridization are detected by the PCR technique. An additional 9 patient samples had clonal IgH gene rearrangements that were detectable by PCR alone. Eight of these nine patients had a history of a clonal hematopoietic process at either the morphologic or molecular level, and six had a history of a B-cell malignancy. It is likely that these specimens contained clonal lymphoid populations undetected by the Southern hybridization technique. Thus, the diagnostic sensitivity and specificity of the PCR method for the detection of B-cell tumors were 91% and 95%, respectively. The combination of improved analytical sensitivity and specimen flexibility of the IgH PCR assay could make it the method of choice for the routine detection of clonal IgH gene rearrangements, if minor improvements in the diagnostic sensitivity of the assay can be achieved.

Base Sequence↗
PubMed1993

Optimization for detection of cytomegalovirus by the polymerase chain reaction (PCR) in clinical samples.

PCR is 100 times more sensitive than traditional tube culture for detecting cytomegalovirus (CMV) but may require up to 12 reactions per specimen (Sandin et al., 1991). In order to make the assay practical for use in a clinical laboratory the procedure used to detect CMV must be simplified. In this study, the effect of reducing the number of reactions per specimen on sensitivity and specificity of the PCR assay was evaluated. 53 residual samples from specimens processed for CMV by shell vial assay/routine tube tissue culture (SVA/TTC) were analyzed by PCR. The residual samples were separated into a supernatant and pellet fractions, then tested for CMV with primers to the immediate early (IEP) and late protein (LP) genes using a nested procedure. To exclude false negatives due to the presence of inhibitors in the sample fractions, all fractions were tested for the presence of the human myosin heavy chain gene also using a nested procedure. SVA/TTC had a sensitivity and specificity of 52/96% in comparison to PCR when data from all 12 PCR reactions was considered. However, high sensitivity and specificity were retained when only the data of the IEP primers with two samples were considered. The results from examining only the 1:10 dilution of pellet and the undiluted supernatant by PCR provided a 60% increase in sensitivity over SVA/TTC, high specificity and a clinically feasible assay.

Base Sequence↗
PubMed1991

Anomalous kinetic visual fields found in family members of patients with a confirmed diagnosis of Gilles de la Tourette syndrome.

Three visual manifestations of Gilles de la Tourette syndrome (TS), a neuropsychiatric disorder, have been previously reported. In this paper we report anomalies in the measured kinetic paracentral visual field of TS patients and their family members. We found that 96% of TS patients exhibited paracentral kinetic visual field defects (nasal and temporal steps, enlargement, "ringing," and/or baring of the blind spot). Ninety-three percent of fathers of TS children and, surprisingly, about 80% of mothers exhibit these characteristic visual field anomalies. Sample data and examples of family studies are reported.

Adolescent↗
PubMed1990

An analysis of abnormalities of the retinoblastoma gene in human ovarian and endometrial carcinoma.

The altered expression of the human retinoblastoma (RB) gene has been demonstrated to play an important role in the pathogenesis of RB and other tumors. To determine whether the RB gene might be involved in the pathogenesis of human ovarian and endometrial cancer, DNA from 24 human ovarian tumors, 3 normal ovaries, 3 endometrial carcinomas, and 1 endometrial hyperplasia was examined with an RB complementary DNA probe. Evidence for homozygous deletion of the RB gene was observed in only one specimen. Interestingly, the specimen was an endometrioid tumor of the ovary of low malignant potential (LMP). This patient experienced rapid progression of the tumor and died 8 months after diagnosis. Abnormalities of the RB gene may be involved in the aggressive biologic behavior of certain forms of ovarian carcinoma, particularly those of LMP.

Aged↗
PubMed1990

Serous papillary adenocarcinoma of the endometrium. Analysis of proto-oncogene amplification, flow cytometry, estrogen and progesterone receptors, and immunohistochemistry.

Primary and metastatic tumor tissues of serous papillary adenocarcinoma of the endometrium were examined for the following: (1) amplification of int-2, c-erbB-2 and c-myc proto-oncogenes by Southern blot hybridization; (2) DNA ploidy by flow cytometric study; (3) and expression of specific proteins, such as estrogen and progesterone receptors, keratin, vimentin, and carcinoembryonic antigen (CEA) using immunohistochemical and biochemical techniques. Amplification of c-myc was observed in the specimens from the endometrium (ten-fold) and from omental metastasis (five-fold). Both int-2 and c-erbB-2 amplification were not observed. The tumor showed aneuploidy, with the specimens from the endometrium and omental metastasis exhibiting multiple populations of aneuploid tumor cells. Estrogen and progesterone receptors could not be detected biochemically; however, immunohistochemically, estrogen receptors were observed in tumor cells forming papillary structures but not in the tumor cells of the solid, more poorly differentiated areas. A similar distribution was observed for both low and high molecular weight keratin. The findings of c-myc amplification and aneuploidy in the serous papillary adenocarcinoma of the endometrium are consistent with its aggressive behavior observed clinically and emphasize the importance of distinguishing this lesion from other types of endometrial carcinoma.

Blotting, Southern↗
PubMed1990

Protooncogene amplification and tumor ploidy in human ovarian neoplasms.

DNA from 24 ovarian tumors, including 16 carcinomas, was examined for amplification of the proto-oncogenes c-myc, int-2, and rc-erbB-2. All cases of carcinoma were also examined by flow cytometry for DNA ploidy and cell cycle analysis, and eight cases of carcinoma were examined for estrogen and progesterone receptors. Protooncogene amplification was not detected in the DNA of benign ovarian neoplasms, or of ovarian carcinomas with low malignant potential. Amplification of c-myc was detected in six of 12 cases of invasive carcinoma, int-2 amplification was present in one case, and c-erbB-2 amplification was not detected in any case. Among the seven cases evidencing protooncogene amplification, three cases showed aneuploidy in tumor DNA, while four showed diploidy. Two cases which showed aneuploidy in tumor DNA did not demonstrate any degree of protooncogene amplification. Protooncogene amplification was frequently associated with morphologic nuclear anaplasia and high mitotic count. Six of the seven cases demonstrating c-myc or int-2 were of the serous type or showed some degree of serous differentiation, while none of the four cases of purely mucinous carcinoma had evidence of amplification. While the total number of cases in the study was limited, it would appear from the trend demonstrated by the data that protooncogene amplification (particularly c-myc) may be involved in the pathogenesis of aggressive common epithelial tumors of the ovary.

Adenocarcinoma, Mucinous↗