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Biomedical subjects

Thomas G Wilson

Publications and source records attributed to Thomas G Wilson.

33 records · Page 2Linked to original sources
PubMed2003

Juvenile hormone involvement in Drosophila melanogaster male reproduction as suggested by the Methoprene-tolerant(27) mutant phenotype.

Juvenile hormone (JH) involvement in male reproduction is poorly understood. In Drosophila melanogaster adults, JH deficiency has been shown to result in lowered protein synthesis in male accessory glands. To probe additional roles, we have examined males homozygous for a null allele of Methoprene-tolerant (Met). This gene is involved in the action of JH, possibly at the JH receptor level, and Met(27) null mutants reflect a diminution of JH action. Met(27) males were found to have reduced protein accumulation in male accessory glands and to court and mate wild-type females much less avidly than do either Met(+) or Met(27); Met(+) transgenic males. Exposure of Met(27) males to methoprene partially rescued the courtship deficiency. However, sperm transfer as reflected by fertility of Met(27) fathers was found to be similar to that of Met(+). Taken together with previous work examining the JH-deficient mutant apterous, these results corroborate JH involvement in protein synthesis in the male accessory glands and suggest a role for JH in promoting male mating behavior in these flies.

Alleles↗
PubMed2003

Immediate implants covered with connective tissue membranes: human biopsies.

BACKGROUND: Osseointegration has been shown to occur around implants placed immediately after tooth extraction in humans. To date, such osseointegration has been achieved only with titanium plasma-sprayed (TPS) implants placed in extraction sockets with a bone-to-implant distance of less than 2 mm. In a previous report, when this horizontal defect dimension (HDD) exceeded 2 mm, the resulting percentage of bone-to-implant contact was reduced, indicating that the immediate technique would be limited in most cases to non-molar teeth. In an attempt to improve the bone-to-implant contact and the initial bone-to-implant contact in a vertical dimension, the implant surface, the type of membrane, and the method of membrane placement used in a previous study by our group were modified. METHODS: Ten large-grit sandblasted, acid-attacked (SLA) titanium implants were placed into immediate extraction sites in 5 patients. HDDs of 0.0 to 1.5 mm (controls), 1.5 to 4.0 mm, and >4.0 mm were used. Following insertion, implants were completely covered with a connective tissue membrane. This was in contrast to the use of an expanded polytetrafluoroethylene (ePTFE) membrane penetrated by the neck of the implant in our previous report. Primary closure of soft tissue flaps was achieved in each case. Six months after placement, 7 of the implants were histologically examined. RESULTS: Osseointegration occurred across all HDDs, with the percentage of bone-to-implant contact in the 0.0 to 1.5 mm HDDs similar to that seen in the >4.0 mm HDDs. The first bone-to-implant contact measured vertically was similar in both the smaller and larger HDDs. CONCLUSIONS: Osseointegration was successful in immediate implant placement sites with horizontal defect dimensions wider than 4 mm in humans when SLA titanium implants were completely covered with connective tissue membranes. It remains undetermined whether the different type of membrane, placement of the membrane, type of implant surface, or a combination of these 3 factors were responsible for the improved osseointegration in HDDs >4 mm. Further study is needed.

Alveolar Process↗
PubMed2003

Surgical templates.

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Dental Implantation, Endosseous↗
PubMed2002

Antibiotics.

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Anti-Bacterial Agents↗
PubMed2002

Putting science into practice: the clinical translation of medical approaches.

Proving a relationship between inflammatory periodontal disease and systemic disease will bring significant changes to the average periodontal practice. First, there will be a time of confusion with competing ideas and techniques. Determination of acceptable levels of inflammation will bring an end to the discussion. As this transition occurs, patients will need to be kept as current as possible without being unnecessarily alarmed. The average periodontal practice will shift its emphasis toward controlling inflammation. Initially, this will mean more periodontal surgery, more tooth extraction, and more implant placement. In the long run, periodontal disease may be treated by the patient with anti-inflammatory medications; by the general dentist with local therapy including antibiotics and anti-inflammatory medications, advanced nonsurgical techniques, and surgery; and, less frequently, by the periodontist.

Anti-Bacterial Agents↗
PubMedDate not supplied

The molecular site of action of juvenile hormone and juvenile hormone insecticides during metamorphosis: how these compounds kill insects.

Studies in a variety of insects during the past four decades has deepened our understanding of juvenile hormone (JH) physiology, but how this hormone works at the molecular level remains elusive. Similarly, the mechanism of toxicity of JH analogue insecticides is still in question. There is much evidence from laboratory usage that JHAs act as JH agonists and generally show the highest toxicity when applied at the onset of metamorphosis. A physiological basis for the toxicity and morphogenetic effects has been suggested by recent work linking these effects with interference with the expression or action of certain genes, particularly the Broad-Complex (BR-C) transcription factor gene, that direct metamorphic change. Misexpressed BR-C then leads to improper expression of one or more downstream effector genes controlled by BR-C gene products, resulting in abnormal developmental and physiological changes that disrupt metamorphosis. Therefore, JH is a necessary molecule at certain times in insect development but becomes toxic when present during metamorphosis.

Animals↗
PubMedDate not supplied

Why do we resist change?

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Attitude of Health Personnel↗