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Biomedical subjects

J Bennett

Publications and source records attributed to J Bennett.

At least 73 records · Page 4Linked to original sources
PubMed2000

Synovial chondromatosis of the temporomandibular joint: varying presentation in 4 cases.

Synovial chondromatosis is a rare condition in which cartilage is formed in the synovial membrane of a joint. The manifestations of this benign neoplastic process can mimic many common temporomandibular joint and parotid diseases. Four cases of synovial chondromatosis are presented. In each case, atypical presentation, coexisting joint disease, or both caused diagnostic confusion. The histories and physical examinations were initially consistent with more common joint diseases in each case. Imaging provided some insight into diagnosis and was a definitive indication for surgical treatment. Treatment by subtotal synovectomy and by removal of chondromatous nodules were undertaken in each case. No patient in our series has had recurrence of disease or symptoms after surgical treatment.

Adult↗
PubMed2000

HPA-1, 3, 5 genotyping to establish a typed platelet donor panel.

Platelet antigen typing of blood donors is not routinely performed. Usually, ABO-matched platelets are transfused. In situations where the recipient has a human platelet-associated (HPA) antibody resulting in refractoriness to platelet transfusions, post-transfusion purpura or neonatal alloimmune thrombocytopenia, HPA-typed platelets may be required. Having a panel of HPA-typed donors would be helpful. This study utilised PCR-RFLP and PCR-SSP methods to determine the HPA-1, 3, 5 genotypes of 1,000 blood donors to establish a panel of HPA homozygous donors who could donate platelets for patients with anti-HPA-antibodies. The study demonstrates the HPA genotype frequencies in a Western Australian blood donor population and has identified donors who are homozygous for the "aa" and "bb" genotypes for HPA-1, 3 and 5. The Australian Red Cross Blood Service-NW Region can now use these data to develop a panel of HPA-1, 3 and 5 "aa" and "bb" homozygous platelet donors, which can be accessed for patients with HPA antibodies requiring platelet transfusion.

Antigens, Human Platelet↗
PubMed2000

The long-term survival of lower second primary molars in subjects with agenesis of the premolars.

This study investigated 41 subjects, 13 male and 28 female, with agenesis of one or both lower second premolars, and with retained lower second primary molars. Intra-oral radiographs of 59 primary teeth were examined to judge the resorption of the mesial and distal roots, and were measured to record infra-occlusion of the primary teeth and tipping of the adjacent permanent teeth. The study commenced at 11-12 years of age. The mean age at the last measurement was 20 years 6 months (SD 3.62, range 13.6-31.8 years). During the observation period, only two of the 59 primary teeth were exfoliated. Five were extracted, two of which were replaced by upper third molar transplants. Beyond the age of 20 years no teeth were lost. Root resorption varied widely between individuals, but was slow. There was no typical pattern for development of infra-occlusion. Mean infra-occlusion was 0.47 mm (SD 1.13) at 11-12 years, increasing by less than 1.0 to 1.43 mm (SD 1.13) at age 17-18 years. At age 19-20 years, 55 per cent of teeth showed infra-occlusion between 0.5 and 4.5 mm, but 45 per cent showed no infra-occlusion. The space between the first molar and first premolar was a mean of 10.35 mm (SD 0.76) at age 10-12 years compared with the mean width of the second primary molar of 10.53 mm (SD 0.51). The space reduced by less than 0.5 mm to 9.95 mm (SD 1.50) at age 17-18 years. If primary molars are present at 20 years of age they appear to have a good prognosis for long-term survival.

Adolescent↗
PubMed2000

Systemic effects of formoterol and salmeterol: a dose-response comparison in healthy subjects.

BACKGROUND: The main adverse effects of inhaled long acting beta(2) agonists relate to their systemic activity. The systemic effects seen over eight hours after inhalation of three doses of salmeterol and formoterol were therefore compared in normal subjects. METHODS: A double blind, randomised, crossover study was carried out in 16 healthy subjects who inhaled formoterol 24, 48 and 96 microg (via Turbuhaler((R))), salmeterol 100, 200 and 400 microg (via Diskhaler((R))), or placebo on separate days. Heart rate, systolic and diastolic blood pressure, and plasma potassium and glucose concentrations were measured for eight hours following each drug and mean values were used to plot the time course of change after each dose. Mean maximum (or minimum) absolute values were used to construct dose-response curves to calculate the relative dose potency of the two drugs. Lunch was taken after the four hour readings and, since this caused additional changes to the main outcome measures, data from the first four hours are also presented in a post hoc analysis. RESULTS: Both salmeterol and formoterol caused an early dose dependent increase in heart rate and glucose concentrations and a fall in diastolic blood pressure and plasma potassium concentration; formoterol also caused an early increase in systolic blood pressure. The cardiovascular effects occurred more rapidly than the metabolic effects and the response to formoterol was faster than that of salmeterol, apart from the glycaemic response. The effects of salmeterol were slightly more prolonged than those of formoterol, although some dose related effects were apparent at eight hours with both drugs. The relative dose potency for formoterol compared with salmeterol at four and eight hours for the different end points excluding systolic blood pressure ranged from 1.6 to 7.0 after adjusting for baseline values. Relative dose potencies (95% CI) for maximum heart rate and plasma potassium concentrations were 4.1 (3.0 to 5.6) and 5.8 (4.1 to 8.6) over four hours and 2.4 (1.2 to 3.8) and 3.0 (1.2 to 5.7) over eight hours. CONCLUSIONS: Formoterol and salmeterol cause dose related changes in heart rate, diastolic blood pressure, and plasma glucose and potassium concentrations. Formoterol has a more rapid onset for most end points whereas salmeterol has slightly more prolonged activity. Both drugs have a relatively modest therapeutic window. The relative dose potencies of the two drugs for the main end points were similar to the fourfold difference in recommended doses. Some differences in the pharmacological profile of the two drugs emerged and are as yet unexplained.

Adolescent↗
PubMed2000

Point-of-care testing: inspection preparedness.

Point-of-care testing (POCT) in the operating room has changed dramatically since the implementation of the Clinical Laboratory Improvement Amendments (CLIA '88), which became effective in September 1992. With the implementation of CLIA '88, the Health Care Financing Administration (HCFA) mandated that human specimen testing 'for the purpose of diagnosis, prevention, or treatment of any disease or impairment of, or the assessment of the health of human beings', must be performed by a certified laboratory or testing site. To attain and maintain accreditation, the need for more stringent and comprehensive documentation has become imperative. The Joint Commission for the Accreditation of Hospitals (JCAHO), the College of American Pathologists (CAPS), HCFA, and state regulatory agencies require data such as staff credentialling, staff training/competency, procedure manuals, quality control logs, quality assurance/corrective action plans, correlation studies, proficiency testing results, and equipment maintenance logs to assure specimens are analyzed in a reliable manner by competent personnel so as not to jeopardize the safety and well being of the patient. Developing a comprehensive, ongoing survey readiness plan that includes a pre-survey checklist of all the documentation required and having this documentation in order and up to date well in advance of the survey will greatly enhance the probability of a successful survey conducted by the various regulatory agencies.

Accreditation↗
PubMed2000

A survey of World Wide Web use in middle-aged and older adults.

We conducted a survey to document World Wide Web use patterns in middle-aged (ages 40-59), young-old (ages 60-74), and old-old adults (ages 75-92). We conducted this survey of 550 adults 40 years old and over in southeastern Michigan, and the overall response rate was approximately 71%. The results suggested that (a) there are distinct age and demographic differences in individuals who use the Web; (b) middle-aged and older Web users are similar in their use patterns; (c) the two primary predictors for not using the Web are lack of access to a computer and lack of knowledge about the Web; (d) old-old adults have the least interest in using the Web compared with middle-aged and young-old adults; and (e) the primary content areas in learning how to use the Web are learning how to use electronic mail and accessing health information and information about traveling for pleasure. This research may serve as a preliminary attempt to ascertain the issues that must be faced in order to increase use of the World Wide Web in middle-aged and older adults.

Adult↗
PubMed2000

Effect of plant age, larval age, and fertilizer treatment on resistance of a cry1Ab-transformed aromatic rice to lepidopterous stem borers and foliage feeders.

The resistance of vegetative, booting, and flowering stage plants of a variety of an aromatic rice, Oryza sativa L., transformed with a Bacillus thuringiensis Berliner cry1Ab gene under control of the maize phosphoenolpyruvate carboxylase (PEPC) promoter was evaluated against four lepidopterous rice pests--the stem borers Chilo suppressalis (Walker) (Lepidoptera: Crambidae) and Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae), and the foliage feeders Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) and Naranga aenescens Moore (Lepidoptera: Noctuidae). Plants of the cry1Ab-transformed line (no. 827) were more resistant to young larvae of S. incertulas, C. suppressalis, and C. medinalis than control plants at the vegetative stage but not at the flowering stage. Survival of 10-d-old stem borer larvae did not differ on cry1Ab plants and control plants at either the vegetative or flowering stage, but the development of 10-d-old C. suppressalis larvae was retarded on the vegetative stage cry1Ab plants. Immunological analysis also showed an apparent decline in Cry1Ab titer in leaf blades and leaf sheaths at the reproductive stage. In experiments comparing three fertilizer treatments (NPK, PK, and none), there was a significant interaction between fertilizer treatment and variety on larval survival only in whole-plant assays at booting stage with C. suppressalis. On cry1Ab plants, larval survival did not differ significantly among the three fertilizer levels, whereas on control plants survival was highest with the NPK treatment. cry1Ab plants tested at the sixth and seventh generations after transformation were more resistant than control plants to N. aenescens and C. suppressalis, respectively, suggesting that gene silencing will not occur in line 827. The results of the experiments are discussed in terms of resistance management for B. thuringiensis toxins in rice.

Animals↗
PubMed2000

Biodiversity of Asian rice gall midge (Orseolia oryzae Wood Mason) from five countries examined by AFLP analysis.

Amplified fragment length polymorphism (AFLP) analysis was used to assess the biodiversity of one of the most important dipteran pests of cereals, the Asian rice gall midge (Orseolia oryzae Wood Mason). Larvae and pupae were collected at 15 locations in five Asian countries and preserved in 95% ethanol for storage, shipment, and DNA extraction using cetyltrimethylammonium bromide (CTAB). Although only approximately 1 microg of DNA was extracted from a single pupa or larva, the use of several AFLP primers in various combinations meant that this amount of DNA was sufficient to allow many DNA fingerprints to be made per individual. Fingerprints were sufficiently reproducible, especially during selective amplification, to allow the genetic diversity within a field population to be characterized. Extraction of DNA from a pool of 20 insects yielded AFLP fingerprints in which variation among individuals was sacrificed in favor of detecting differences among populations. For each location, pooled DNA was amplified with three primer pairs. A total of 261 distinct AFLP bands were identified for the 45 fingerprints. Cluster analysis, performed by the unweighted pair-group method (UPGMA), separated the populations into two distinct groups. Group I included two populations from Guangdong province of southern China and one each from Laos and Imphal in northeastern India, while group II was comprised of eleven populations from elsewhere in India (Assam, Orissa, Madhya Pradesh, Andhra Pradesh, and Kerala) and from Nepal and Sri Lanka. AFLP analysis provided insight into the origins of gall midge biotypes. In 1992, the prevailing biotype in Imphal changed from Indian biotype 3 to a new biotype 3M. Our data show that biotype 3M belongs to group I and did not arise by a recent mutation from biotype 3, which belongs to group II. By contrast, Indian biotypes 2 and 4 are likely to have diverged through recent mutation and selection, as are Chinese biotypes 1 and 4. The almost simultaneous emergence of new biotypes in Kerala and Sri Lanka during 1985-1988 was most probably coincidental, because these biotypes are not closely related. AFLP fingerprints were also able to detect sexual dimorphism in the DNA of adult gall midges and to distinguish gall midge from its major parasite Platygaster oryzae.

Animals↗
PubMed2000

Disease expression of RP1 mutations causing autosomal dominant retinitis pigmentosa.

PURPOSE: To determine the disease expression in heterozygotes for mutations in the RP1 gene, a newly identified cause of autosomal dominant retinitis pigmentosa (adRP). METHODS: Screening strategies were used to detect disease-causing mutations in the RP1 gene, and detailed studies of phenotype were performed in a subset of the detected RP1 heterozygotes using electroretinography (ERG), psychophysics, and optical coherence tomography (OCT). RESULTS: Seventeen adRP families had heterozygous RP1 changes. Thirteen families had the Arg677ter mutation, whereas four others had one of the following: Pro658 (1-bp del), Ser747 (1-bp del), Leu762-763 (5-bp del), and Tyr1053 (1-bp del). In Arg677ter RP1 heterozygotes, there was regional retinal variation in disease, with the far peripheral inferonasal retina being most vulnerable; central and superior temporal retinal regions were better preserved. The earliest manifestation of disease was rod dysfunction, detectable as reduced rod ERG photoresponse maximum amplitude, even in heterozygotes with otherwise normal clinical, functional, and OCT cross-sectional retinal imaging results. At disease stages when cone abnormalities were present, there was greater rod than cone dysfunction. Patients with the RP1 frameshift mutations showed similarities in phenotype to those with the Arg677ter mutation. CONCLUSIONS: Earliest disease expression of RP1 gene mutations causing adRP involves primarily rod photoreceptors, and there is a gradient of vulnerability of retinopathy with more pronounced effects in the inferonasal peripheral retina. At other disease stages, cone function is also affected, and severe retina-wide degeneration can occur. The nonpenetrance or minimal disease expression in some Arg677ter mutation-positive heterozygotes suggests important roles for modifier genes or environmental factors in RP1-related disease.

Adolescent↗
PubMed2000

Gene therapy for retinitis pigmentosa.

Retinitis pigmentosa (RP) is a group of retinal degenerative diseases in which there is a slow and progressive loss of photoreceptors. There is no cure for RP and photoreceptor loss leads ultimately to blindness. There has been tremendous progress in the last decade in delineating the molecular basis of RP. Simultaneously, gene transfer experiments have demonstrated that it is possible to deliver transgenes to the retina in vivo in a stable and efficient fashion with minimal toxicity. Proof-of-principle for gene therapy for RP has been established in a number of different animal models. While much more progress needs to be made before moving from the laboratory to the clinic, gene therapy now holds much promise for slowing or even preventing blindness due to RP.

Animals↗
PubMed1999

Basic fibroblast growth factor induces a transformed phenotype in normal human melanocytes.

Basic fibroblast growth factor (bFGF or FGF-2) is produced by nearly all melanomas in vitro and in vivo but not by normal melanocytes, which require exogenous bFGF for growth. In this study, we transduced normal human melanocytes to overexpress two forms of bFGF: (bFGF-Long and bFGF-Short) using replication-deficient adenovirus 5 vectors. bFGF-Long induced the 17.8, 22.5, 23.1 and 24.2 kDa forms of bFGF, whereas bFGF-Short induced only the 17.8 kDa mature form. Growth of cultured melanocytes transduced with either vector was similar to that of nevus and melanoma cells and was independent of exogenous bFGF and of insulin/insulin-like growth factor 1, and cyclic AMP enhancers, requiring only phorbol ester as an exogenous mitogen. Like primary melanoma cells, transduced normal melanocytes grew anchorage independently in soft agar. When injected into the dermis of human skin grafted to mice, bFGF-transduced melanocytes proliferated for at least 20 days, whereas cells from control cultures showed poor survival and no proliferation. These results demonstrate that bFGF upregulation is a critical component in melanoma progression.

Adenoviridae↗
PubMed1999

Infection with adeno-associated virus may protect against excitotoxicity.

Gene therapy has developed as a promising approach for therapy in a broad variety of conditions. Viral vectors have been developed that may replace a defective gene, prevent expression of a mutant gene, or deliver a protective gene and thereby delay cellular loss. Using adeno-associated virus containing green fluorescent protein (AAV-GFP) we were able to specifically transduce cells located in the inner retina and induce over-expression of GFP in adult rat retinae. The delivery and expression of GFP had no influence themselves on retinal ganglion cell survival. Administration of the reporter vector AAV-GFP provided retinal ganglion cells with slight but significant protection from intravitreal NMDA. This was a locally mediated phenomenon; greater protection was seen in regions with more transduced cells. Any evaluation of the efficacy of a putative viral vector should consider the possible protective or toxic effect of the native virus.

Animals↗
PubMed1999

Stable transgene expression in rod photoreceptors after recombinant adeno-associated virus-mediated gene transfer to monkey retina.

Recombinant adeno-associated virus (rAAV) is a promising vector for therapy of retinal degenerative diseases. We evaluated the efficiency, cellular specificity, and safety of retinal cell transduction in nonhuman primates after subretinal delivery of an rAAV carrying a cDNA encoding green fluorescent protein (EGFP), rAAV. CMV.EGFP. The treatment results in efficient and stable EGFP expression lasting >1 year. Transgene expression in the neural retina is limited exclusively to rod photoreceptors. There is neither electroretinographic nor histologic evidence of photoreceptor toxicity. Despite significant serum antibody responses to the vector, subretinal readministration results in additional transduction events. The findings further characterize the retinal cell tropism of rAAV. They also support the development of studies aimed ultimately at treating inherited retinal degeneration by using rAAV-mediated gene therapy.

Animals↗