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Biomedical subjects

J E Kennedy

Publications and source records attributed to J E Kennedy.

At least 19 recordsLinked to original sources

Building on our accomplishments.

BACKGROUND AND OVERVIEW: There are at least five forces--knowledge, finances, diversity, faculty and government--that have the potential to change the current model of dental education significantly in the new century. The author explores these forces and attempts to project their future impact on dental education and the profession. CONCLUSIONS: Our understanding of the etiology and pathogenesis of oral diseases will increase, though likely not enough to facilitate the elimination of either dental caries or adult-onset periodontitis. A mandatory year of additional formal education in the form of a postgraduate residency will become necessary. Current trends in the sources of revenue supporting dental education will continue, and dental education will face a financial crisis. The changing ethnic and racial diversity of the United States and the dental work force will require curricular changes to prepare students to meet the oral health needs of diverse populations. The current shortage of full-time dental faculty members will continue, and dental schools will need to redefine what it means to be a faculty member. Finally, the continuing decline in the dentist:population ratio and a peak in the actual number of active dentists will cause government to again question the adequacy of the dental work force. PRACTICE IMPLICATIONS: Academic dentistry faces a new century with new challenges, all of which have implications for current and future dental practitioners. The extent to which these challenges are successfully met will depend on the degree to which those with a vested interest in a thriving profession come together for the mutual benefit of all.

Cultural Diversity↗

Exposures to blood and body fluids among dental school-based dental health care workers.

A survey of United States dental schools was conducted to determine the annual incidence of reported percutaneous and mucosal exposures to blood and other body fluids among dental school-based dental health care workers (DHCW). A response rate of 51.9 percent provided information on 10,433 DHCW and 1.6 million student clinic and 169,836 school-based faculty practice patient visits. This response represents approximately half of all DHCW and student clinic visits in U.S. dental schools in AY 1996/1997. A total of 652 exposures were reported, of which 629 occurred in student clinics. Dental schools averaged twenty-three reported exposures per year, and the overall annual reported exposure rate in student clinics was 4.0/10,000 patient visits and 1.3/10,000 in faculty practice. Dental students accounted for 62.5 percent of all reported exposures, a rate of 106.3/1000 students per year. The exposure rate for dental students was significantly greater that any other category of DHCW. Expressed in terms of person years, an exposure rate of 0.17 was comparable to that reported for dental schools but considerably less than found in other dental care settings. A second survey directed to individual DHCW drew responses from only 8.3 percent of the 10,433 DHCW. Among these respondents, 31 percent of those acknowledging an exposure reported it. A judgment that the injury was not serious, the time necessary to report an exposure, and a belief that the patient was healthy were the primary reasons for not reporting. The results of this study provide dental schools with benchmarks for comparing their reported exposure experience and assessing programs intended to prevent and manage exposures.

Benchmarking↗

Identification of novel alternatively spliced isoforms of the tropomyosin-encoding gene, TMnm, in the rat cochlea.

Analysis of a rat cochlear cDNA library for the expression of the non-muscle (nm) tropomyosin (TM)-encoding gene (TMnm), demonstrated that four nm isoforms were present. These four TMnm variants are NM-1, NM-2, NM-3 and NM-4. Nucleotide (nt) sequencing revealed that all these isoforms expressed the nm exon 1b sequence, but varied in their usage of the alternatively spliced exons 6a and b and 9a/b and d, representing skeletal muscle (sk) (exons 6b and 9a/b) and nm (6a and 9d) sequences. A novel exon 9 (designated as exon 9c) was associated with the NM-4 isoform and was also found to be expressed in the cochlea. Comparisons of the nt and amino acid (aa) sequences demonstrated a high homology between rat, mouse and human sequences encoding the 'classical' nm isoform, TM30nm, which is designated herein as NM-1. The rat NM-1 nt homology with mouse and human sequences also included the 3' untranslated region. Homologies were found between aa sequences of the C termini of NM-1 and the TM alpha smooth muscle and TM beta nm isoforms, between the sk sequence of NM-3 and the TM alpha and beta sk isoforms, and between the novel 9c sequence of NM-4 and the TM alpha brain-1 isoform. These data predict that the nm isoforms share biochemical properties described for the other TM isoforms.

Alternative Splicing↗

Intraoperative consultation of ovarian neoplasms.

A review of 313 intraoperative consultations and/or frozen section evaluations of neoplasms of the ovary was conducted. The intraoperative diagnosis of benign or malignant was compared with the diagnosis found at permanent section. Only six cases were deferred to permanent section. The overall accuracy was 93.9%. The sensitivity was 72.7%, and this was explained by the high proportion of borderline or low malignant cell tumors in this series. The specificity and predictive values were in excess of 95%. Thirteen cases were diagnosed incorrectly at intraoperative consultation. Eight of these were judged to be sampling errors, one was due to poor technical quality, and four were attributed to interpretation errors. Intraoperative consultation is, and should continue to be, a valuable tool in the evaluation of ovarian neoplasms.

Diagnostic Errors↗

Platelet-derived growth factor and dexamethasone combined with a collagen matrix induce regeneration of the periodontium in monkeys.

Platelet-derived growth factor (PDGF) and the glucocorticoid dexamethasone combined with a collagen carrier matrix (CM) induced regeneration of the periodontium in monkeys. Regeneration was stringently defined as: (1) new cementum, (2) new supra-crestal bone extending coronally from the residual alveolar interdental septum and (3) functionally-oriented periodontal ligament fibers attaching new cementum to new bone. A single application of PDGF/dexamethasone/CM or CM was placed in debrided lesions of experimental periodontitis displaying 3-5 mm of attachment loss associated with horizontal and angular bony defects. Regeneration, judged histologically by these criteria and quantified by computer assisted histomorphometry after 4 weeks, was present only in PDGF/dexamethasone/CM treated lesions and not in those treated with CM or debridement alone. PDGF/dexamethasone/CM induced 5-fold more new cementum and ligament, and 7-fold more supra-crestal bone than control treatments. The presence of substantial amounts of regenerated periodontium including increased height of the alveolar bone; fill of vertically resorbed interdental alveolar septa in PDGF/dexamethasone/CM treated lesions suggests that this combination may provide a new therapeutic agent for the regeneration of lesions of periodontitis associated with horizontal as well as angular bony defects.

Alveolar Process↗

The value of endocervical curettage at time of cervical cone biopsy.

Two hundred eighty-nine patients were evaluated over a 23-month period to assess the efficacy of postcone biopsy endocervical curettage at the time of cervical conization. One hundred eleven patients were excluded because the endocervical curettage was insufficient or not performed, the final pathology on the cone biopsy and endocervical curettage revealed no dysplasia or cancerous process, or the endocervical margins were not assessed, leaving a total of 178 patients in the study population. A negative conization endocervical margin virtually assures no disease in the upper endocervical canal. The negative predictive value in this study population was 97%. We conclude that routine endocervical curettage is unnecessary for most patients and should be primarily considered for patients who are postmenopausal or for those receiving suboptimal conizations.

Adolescent↗

Characterization of the allelic differences in the mouse cardiac alpha-myosin heavy chain coding sequence.

We have obtained and sequenced the coding sequence of the mouse cardiac alpha-myosin heavy chain (Myhc alpha) from the A/J, BALB/cByJ, C57BL/6J, and DBA/2J inbred mouse strains. Overlapping cDNA sequences were obtained using RNA-PCR and anchor-PCR techniques for these studies. In the A/J mouse strain, the full-length message is 5989 bp long and encodes for a protein consisting of 1938 amino acids (Mr 223,689). The protein deduced sequence of the A/J Myhc alpha was compared with corresponding sequences of human and rat Myhc alpha and beta. These results demonstrated that the mouse Myhc alpha is highly conserved and has maintained the alpha-isoform-specific divergent cluster observed in other Myhc alpha proteins. One difference was the loss of a glutamine at residue 1932, which is due to a change in an RNA splicing site sequence. Allelic variability was observed in both nucleotide and amino acid sequences among the four different inbred mouse strains and generally appears to be random in nature. Three of the nucleotide changes resulted in a different amino acid, while the remaining 46 were silent substitutions.

Alleles↗

Platelet-derived and insulin-like growth factors stimulate regeneration of periodontal attachment in monkeys.

Regeneration of cementum, ligament, bone and new attachment was achieved by introducing mixtures of recombinant human platelet-derived growth factor and insulin-like growth factor into debrided lesions of experimentally induced periodontitis in monkeys. This growth factor therapeutic regimen induced the regeneration of nearly 50% of the lost attachment within 4 weeks. New attachment in some cases included regeneration of horizontally resorbed interdental septa. These observations suggest that predictable, clinically significant gains in new attachment may be possible through the use of highly purified human recombinant growth factors delivered to debrided lesions of adult periodontitis in appropriate, inert carrier vehicles.

Alveolar Bone Loss↗

DNA analysis of atrial myxomas.

The atrial myxoma is a primary tumor of the heart which may have an uncertain clinical course. In this study, we performed flow cytometric DNA analysis of 15 paraffin-embedded atrial myxomas and correlated DNA ploidy status and proliferative fraction with clinical findings. Twelve of 15 cases (80 percent) were diploid and the remaining three cases (20 percent) were aneuploid. Two patients with aneuploid histograms were free of tumor at the time follow-up; the third patient experienced local tumor recurrence and metastases. Five patients with diploid myxomas demonstrated an elevated (greater than or equal to 17 percent) proliferative cell cycle fraction; four of these patients experienced embolic phenomenon or tumor recurrence. This pilot study suggests that an atrial myxoma with either aneuploid DNA content or elevated proliferative fraction may be associated with aggressive biologic behavior.

Aneuploidy↗

Monitoring bovine viral diarrhea virus vaccines for adventitious virus, using T1 ribonuclease viral RNA oligonucleotide fingerprinting.

Viral RNA oligonucleotide fingerprinting was used to discriminate 3 cytopathic vaccine bovine viral diarrhea viruses (BVDV) grown in medium supplemented with serum contaminated with noncytopathic BVDV from the same 3 viruses grown in cell culture free of BVDV. Oligonucleotide fingerprinting also effectively discriminated between reference Singer BVDV, NADL BVDV, and New York-1 BVDV grown in BVDV-free noncontaminated or BVDV-contaminated cell cultures. Oligonucleotide fingerprint mapping of viral RNA maybe used to determine the purity of virus stocks, as well as that of BVDV vaccines.

Animals↗

Investigation of bovine viral diarrhea virus infections in a range beef cattle herd.

Bovine viral diarrhea virus (BVDV) infections resulting in clinical disease developed in calves, despite vaccination of dams and high maternal BVDV antibody titers in calves. Eight persistently infected (PI) calves born to immunocompetent dams were identified in the herd. Neutralizing BVDV antibody titers of PI calves had decreased greatly by the time the calves were 1 to 2 months old. Antibody titers of PI calves decreased more rapidly than antibody titers of calves that were not PI. Reduced antibody titers in PI calves allowed detection of BVDV in serum specimens of all PI calves by the time they were 8 weeks old. Persistent infection in suspect calves was detectable serologically and was confirmed by virologic examination of serum specimens 4 months after weaning, when the calves were 9 months old. Growth rates were reduced in viremic calves.

Animals↗