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Biomedical subjects

J Dover

Publications and source records attributed to J Dover.

9 recordsLinked to original sources
PubMed2000

Synopsis of laser assisted hair removal systems.

Conventional treatment options for hypertrichosis and hirsutism are tedious and time consuming. Laser hair removal offers an efficient way to permanently reduce excessive hair growth. Hair is damaged using the principle of selective photothermolysis with wavelengths of light well absorbed by follicular melanin and pulse durations that selectively thermally damage the target without damaging surrounding tissue. Patients with dark hair and light skin are ideal candidates. Multiple treatments (3 to 6) performed every 6-8 weeks are necessary to achieve a permanent reduction of hair growth. As the field develops, a better sense of the effectiveness of laser hair removal will evolve and reasonable expectations will be determined.

Hair Removal↗
PubMed1998

Treating psoriasis.

Explore the source record for details and available documents.

Administration, Topical↗
PubMed1998

Glucose sensing and signaling by two glucose receptors in the yeast Saccharomyces cerevisiae.

How eukaryotic cells sense availability of glucose, their preferred carbon and energy source, is an important, unsolved problem. Bakers' yeast (Saccharomyces cerevisiae) uses two glucose transporter homologs, Snf3 and Rgt2, as glucose sensors that generate a signal for induction of expression of genes encoding hexose transporters (HXT genes). We present evidence that these proteins generate an intracellular glucose signal without transporting glucose. The Snf3 and Rgt2 glucose sensors contain unusually long C-terminal tails that are predicted to be in the cytoplasm. These tails appear to be the signaling domains of Snf3 and Rgt2 because they are necessary for glucose signaling by Snf3 and Rgt2, and transplantation of the C-terminal tail of Snf3 onto the Hxt1 and Hxt2 glucose transporters converts them into glucose sensors that can generate a signal for glucose-induced HXT gene expression. These results support the idea that yeast senses glucose using two modified glucose transporters that serve as glucose receptors.

Amino Acid Sequence↗
PubMed1997

The substitution of digital images for dermatologic physical examination.

OBJECTIVE: To investigate the diagnostic accuracy of clinicians viewing a patient's history and static digital image set compared with clinicians who conducted office-based physical examinations of the same patients. DESIGN: Observational study. SETTING AND PATIENTS: One hundred sixteen adult patients presenting with dermatologic symptoms in a university-based practice who consented to have their skin conditions documented with a still digital camera according to a standardized protocol. MAIN OUTCOME MEASURES: Concordance between office-based dermatologists' diagnoses and 2 remote clinicians' diagnoses using still digital images (resolution, 92 dots per inch) and identical medical history data to render diagnoses. RESULTS: When photographic quality was high and office-based clinician certainty was high, remote clinicians were in agreement more than 75% of the time. Office-based and remote clinicians were in agreement 61% to 64% of the time for all cases. No specific disease category appeared to be more or less amenable to diagnosis based on still digital imagery. The diagnostic certainty of the office-based clinician (reported from 0-10) had the most impact on agreement. When cases with office-based clinician certainty of no more than 7 were compared with cases with certainty of at least 9, agreement increased 54% for remote clinician 1 and 111% for remote clinician 2. As an isolated variable, photographic quality had a modest impact on agreement. CONCLUSIONS: Still digital images can substitute for the dermatologic physical examination in up to 83% of cases. This study provides validation of the store-and-forward concept of telemedicine as applied to dermatology. These results serve as the foundation for field testing of the concept in primary care settings.

Adolescent↗
PubMed1996

Two glucose transporters in Saccharomyces cerevisiae are glucose sensors that generate a signal for induction of gene expression.

Glucose is the preferred carbon source for most eukaryotic cells and has profound effects on many cellular functions. How cells sense glucose and transduce a signal into the cell is a fundamental, unanswered question. Here we describe evidence that two unusual glucose transporters in the yeast Saccharomyces cerevisiae serve as glucose sensors that generate an intracellular glucose signal. The Snf3p high-affinity glucose transporter appears to function as a low glucose sensor, since it is required for induction of expression of several hexose transporter (HXT) genes, encoding glucose transporters, by low levels of glucose. We have identified another apparent glucose transporter, Rgt2p, that is strikingly similar to Snf3p and is required for maximal induction of gene expression in response to high levels of glucose. This suggests that Rgt2p is a high glucose-sensing counterpart to Snf3p. We identified a dominant mutation in RGT2 that causes constitutive expression of several HXT genes, even in the absence of the inducer glucose. This same mutation introduced into SNF3 also causes glucose-independent expression of HXT genes. Thus, the Rgt2p and Snf3p glucose transporters appear to act as glucose receptors that generate an intracellular glucose signal, suggesting that glucose signaling in yeast is a receptor-mediated process.

Amino Acid Sequence↗
PubMed1994

Complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII.

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome VIII reveals that it contains 269 predicted or known genes (300 base pairs or larger). Fifty-nine of these genes (22 percent) were previously identified. Of the 210 novel genes, 65 are predicted to encode proteins that are similar to other proteins of known or predicted function. Sixteen genes appear to be relatively recently duplicated. On average, there is one gene approximately every 2 kilobases. Although the coding density and base composition across the chromosome are not uniform, no regular pattern of variation is apparent.

Base Composition↗
PubMed1988

Mutational analysis of the GAL4-encoded transcriptional activator protein of Saccharomyces cerevisiae.

The GAL4 protein of Saccharomyces cerevisiae binds to DNA upstream of each of six genes and stimulates their transcription. To locate regions of the protein responsible for these processes, we identified and characterized 88 gal4 mutations selected in vivo to reduce the ability to GAL4 protein to activate transcription. These mutations alter two regions of GAL4 protein: the DNA binding domain, and the transcription activation domain. Some mutations in the DNA binding domain that abolish the ability of GAL4 protein to bind to DNA in vitro change amino acid residues proposed to form a zinc finger, confirming that this structure is indeed involved in DNA binding. Four different amino acid changes in the zinc finger appear to reduce (but not abolish) the affinity of GAL4 protein for zinc ions, thereby identifying some of the amino acids involved in forming the zinc-binding structure. Several other mutations that abolish the DNA binding activity of the protein alter the 20 amino acids adjacent to the zinc finger, suggesting that these residues are part of the DNA binding domain. Two amino acid changes in the region adjacent to the zinc finger also appear to affect the ability of GAL4 protein to bind zinc ions, suggesting that this region of the protein can influence the structure of the zinc binding domain. The transcription activation domain of GAL4 protein is remarkably resistant to single amino acid changes: only 4 of the 42 mutations that alter this region of the protein are of the missense type. This observation is consistent with other lines of evidence that GAL4 protein possesses multiple transcription activation domains with unusual sequence flexibility.

Alleles↗
PubMed1987

Mutations that inactivate a yeast transcriptional regulatory protein cluster in an evolutionarily conserved DNA binding domain.

The protein encoded by the GAL4 gene of the yeast Saccharomyces cerevisiae binds to DNA upstream of several genes and activates transcription. To try to understand these processes, we have undertaken a genetic analysis of GAL4. Here we report that nearly all missense mutations in GAL4, selected in vivo to lack function of the protein, cluster in the small region of the gene that encodes the DNA binding domain. About half of these mutations alters a cysteine-rich region of the protein highly homologous to several eukaryotic DNA binding proteins; the other half alters some of the 20 amino acids adjacent to the cysteine-rich region. Nearly all of the missense mutations that alter the DNA binding domain abolish the DNA binding activity of GAL4 protein measured in vitro. In contrast, nearly all of the mutations that alter the 3' 95% of the gene that encodes the transcription activation function are nonsense or frameshift mutations. These results support the idea that the conserved cysteine-rich sequence motif is directly involved in binding of several eukaryotic transcriptional regulatory proteins to DNA.

Amino Acid Sequence↗