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Biomedical subjects

A Davis

Publications and source records attributed to A Davis.

At least 19 recordsLinked to original sources
PubMed2006

Facial motor function monitored by hand held calipers versus computer-assisted photography.

BACKGROUND: It is essential to have easy to use, reliable tools to assess and compare facial function for clinical records, audit and research purposes. In this study, two different techniques were examined, Hand held calipers (HHC, as described by Burres), and computerised analysis of digital photographs (CAOP) using Adobe Photoshop 7. The aim of this study was to determine the level of agreement between two operators (physiotherapist) using HHC to measure the distance between facial landmarks, and the level of agreement between two operators (photographers) using CAOP to measure the same distance between facial landmarks and explore whether these two techniques can be used interchangeably. METHOD: The distance between facial landmarks was measured, with the face at rest and following four standard facial expressions. All measurements were repeated one week later to permit inter/intra-rater reliability over time to be assessed. Nine female volunteers with normal facial function were included in the study. RESULTS: The intra- and inter-rater agreement using CAOP was high whereas the agreement was low when using HHC. CONCLUSION: Hand held calipers proved to be an unreliable technique for monitoring facial function. However digital photography when combined with Adobe Photoshop 7 provides a highly reliable objective measurement tool. It was simple to use, low cost and suitable for use in a clinical environment.

Adult↗
PubMed2006

Genes expressed during the development and ripening of watermelon fruit.

A normalized cDNA library was constructed using watermelon flesh mRNA from three distinct developmental time-points and was subtracted by hybridization with leaf cDNA. Random cDNA clones of the watermelon flesh subtraction library were sequenced from the 5' end in order to identify potentially informative genes associated with fruit setting, development, and ripening. One-thousand and forty-six 5'-end sequences (expressed sequence tags; ESTs) were assembled into 832 non-redundant sequences, designated as "EST-unigenes". Of these 832 "EST-unigenes", 254 ( approximately 30%) have no significant homology to sequences published so far for other plant species. Additionally, 168 "EST-unigenes" ( approximately 20%) correspond to genes with unknown function, whereas 410 "EST-unigenes" ( approximately 50%) correspond to genes with known function in other plant species. These "EST-unigenes" are mainly associated with metabolism, membrane transport, cytoskeleton synthesis and structure, cell wall formation and cell division, signal transduction, nucleic acid binding and transcription factors, defense and stress response, and secondary metabolism. This study provides the scientific community with novel genetic information for watermelon as well as an expanded pool of genes associated with fruit development in watermelon. These genes will be useful targets in future genetic and functional genomic studies of watermelon and its development.

Citrullus↗
PubMed2006

Inhibition of testosterone-induced hyperplasia of the prostate of sprague-dawley rats by pumpkin seed oil.

The oil from the pumpkin (Cucurbita pepo) seed is claimed to be useful in the management of benign prostatic hyperplasia. This investigation seeks to examine the effect of pumpkin seed oil on testosterone-induced hyperplasia of the prostate of rats. Hyperplasia was induced by subcutaneous administration of testosterone (0.3 mg/100 g of body weight) for 20 days. Simultaneous oral administration of either pumpkin seed oil (2.0 and 4.0 mg/100 g of body weight) or corn oil (vehicle) was also given for 20 days. The weights of the rats were recorded weekly, and the influence of testosterone and pumpkin seed oil on the weight gain of the rats was examined. On day 21, rats were sacrificed, and the prostate was removed, cleaned, and weighed. The prostate size ratio (prostate weight/rat body weight) was then calculated. Neither testosterone nor pumpkin seed oil had any significant influence on the weight gain of the rats. Testosterone significantly increased prostate size ratio (P < .05), and this induced increase was inhibited in rats fed with pumpkin seed oil at 2.0 mg/100 g of body weight. The protective effect of pumpkin seed oil was significant at the higher pumpkin seed oil dose (P < .02). We conclude pumpkin seed oil can inhibit testosterone-induced hyperplasia of the prostate and therefore may be beneficial in the management of benign prostatic hyperplasia.

Animals↗
PubMed2005

Recurrent nodal metastases in the posterior triangle: implications for treatment of the atypical tumour.

We studied the incidence of recurrent nodal metastases in level V (posterior triangle) in patients who had previously had a staging or therapeutic dissection of the neck, with or without postoperative radiotherapy. Of 160 patients studied (177 neck dissections), 41 (26%) developed recurrent metastases in the neck. Four patients (3%) developed ipsilateral recurrent disease in level V. In these four patients, level III or IV lymph nodes were shown histologically to have extracapsular spread at the time of the original dissection. All four metastases were located at or just beyond the anatomical boundaries of the posterior triangle. None of the metastases at level V were from oral or oropharyngeal primary tumours.

Adult↗
PubMed2004

Psycho-socio-economic outcomes in acoustic neuroma patients and their carers related to tumour size.

The objective was to explore psycho-socio-economic outcomes of a 2-year cohort of patients having surgery for an acoustic neuroma, and carers and their relationship to tumour size after surgery. The Wessex Patient Carer Questionnaire was designed in conjunction with Patients and Carers, to determine psycho-socio-economic outcomes. The results were juxtaposed against clinical profiles. The House-Brackman (HB) scale was used to assess facial function at 6 and 12 months after operation. The cohort contained 102 patients. There were 87% effective responders. Half were aged below 54 years and 30% had school-aged children. The majority (93%) of patients were operated via the translabyrinthine approach. Patients with large tumours, i.e. greater than 3 cm (28%), had most post-treatment physical problems, including hearing and balance difficulties, and 42% reported difficulty eating in public. Thirty-four per cent felt 'stressed' and 18%'depressed'. After 6 months, facial function was recorded as HB scale 5/6 in 21% of patients but by 1 year only 8% of patients were HB 5/6. Patients and carers were generally very satisfied with their in-patient neurosurgical care, but significantly dissatisfied with post-discharge care - particularly the shortcoming of the community services. The majority of families felt 'unsupported' and only 20% of patients had confidence in their General Practitioner's knowledge. Families faced severe socio-economic disruption and patients"time-off-work' was estimated to cost pound 954,000. Carers carried considerable post-discharge psychological burdens and costs to the public purse were calculated to be pound 52,000.

Adult↗
PubMed2003

Formation and stabilisation of triclosan colloidal suspensions using supersaturated systems.

The aim of this paper is to prepare and stabilise, in situ, colloidal microsuspensions of triclosan using the polymer, hydroxypropyl methylcellulose (HPMC). The suspensions were prepared from supersaturated solutions of triclosan. The cosolvent technique was used to create supersaturation. Propylene glycol and water were used as the cosolvents. The triclosan particles had a large needle-shaped morphology, when grown in the absence of the polymer. Moreover, the particles grew rapidly to sizes greater than 5 micrometer over a period of 7h. When HPMC was added, the particle sizes were in the range 90-250 nm depending on the amount of polymer present in the solutions. The stability of the solutions was evaluated over a period of 40 days during which the particle sizes did not vary. The results were consistent with the mechanism proposed by Raghavan et al. [Int. J. Pharm. 212 (2001b) 213].

Anti-Infective Agents↗
PubMed2002

Wound healing: the role of gap junctional communication in rat granulation tissue maturation.

Granulation tissue maturation is dependent upon the orientation of collagen fibers and cell differentiation. Gap junctions are intercellular membrane gated channels that facilitate direct communication between cells known as gap junctional intercellular communication (GJIC). The hypothesis is that GJIC modulates the maturation of granulation tissue during wound repair. In vitro, GJIC optimizes fibroblast-populated collagen lattice contraction and influences cell morphology. It is reported that LiCl increases GJIC in cultured cardiac myocytes. Polyvinyl alcohol (PVA) sponge implants with central reservoirs were placed within separate subcutaneous pockets on the backs of adult male Sprague-Dawley rats. Each PVA implant received either 20 mM LiCl or saline injections on days 5, 7, and 10 after implantation. On day 11 implants were harvested and processed for light microscopy. By H&E staining LiCl-treated implants showed increased vascularization and decreased cell density compared to saline controls. Polarized light microscopy of Sirius red-stained specimens revealed more intense collagen fiber birefringence secondary to dense, parallel-organized collagen fiber bundles after LiCl treatment. This suggests that LiCl enhancement of GJIC between fibroblasts advances the maturation of granulation tissue. It is proposed that the degree of GJIC between granulation tissue fibroblasts influences both the quantity and the quality of granulation tissue deposited during the wound healing process.

Animals↗
PubMed2002

Occupational exposure to noise and the attributable burden of hearing difficulties in Great Britain.

AIMS: To determine the prevalence of self reported hearing difficulties and tinnitus in working aged people from the general population, and to estimate the risks from occupational exposure to noise and the number of attributable cases nationally. METHODS: A questionnaire was mailed to 22 194 adults of working age selected at random from the age-sex registers of 34 British general practices (21 201 subjects) and from the central pay records of the British armed services (993 subjects). Information was collected on years of employment in a noisy job; and whether the respondent wore a hearing aid, had difficulty in hearing conversation, or had experienced persistent tinnitus over the past year. Associations of hearing difficulty and tinnitus with noise exposure were examined by logistic regression, with adjustment for age, sex, smoking habits, and frequent complaints of headaches, tiredness, or stress. The findings were expressed as prevalence ratios (PRs) with associated 95% confidence intervals (CIs). Attributable numbers were calculated from the relevant PRs and an estimate of the prevalence of occupational exposure to noise nationally. RESULTS: Some 2% of subjects reported severe hearing difficulties (wearing a hearing aid or having great difficulty in both ears in hearing conversation in a quiet room). In men, the prevalence of this outcome rose steeply with age, from below 1% in those aged 16-24 years to 8% in those aged 55-64. The pattern was similar in women, but severe hearing loss was only about half as prevalent in the oldest age band. Tinnitus was far more common in subjects with hearing difficulties. In both sexes, after adjustment for age, the risk of severe hearing difficulty and persistent tinnitus rose with years spent in a noisy job. In men older than 35 years with 10 or more years of exposure, the PR for severe hearing difficulty was 3.8 (95% CI 2.4 to 6.2) and that for persistent tinnitus 2.6 (95% CI 2.0 to 3.4) in comparison with those who had never had a noisy job. Nationally, some 153 000 men and 26 000 women aged 35-64 years were estimated to have severe hearing difficulties attributable to noise at work. For persistent tinnitus the corresponding numbers were 266 000 and 84 000. CONCLUSIONS: Significant hearing difficulties and tinnitus are quite common in men from the older working age range. Both are strongly associated with years spent in a noisy occupation--a predominantly male exposure. The national burden of hearing difficulties attributable to noise at work is substantial.

Adolescent↗
PubMed2002

Anti-Mta associated with three cases of hemolytic disease of the newborn.

The Mta antigen is a low-frequency red blood cell (RBC) surface antigen and is an established antigen of the MNSs blood group system. There has been one report of anti-Mta-induced hemolytic disease of the newborn (HDN) in the literature to date. We describe a family in which three children were affected by neonatal anemia. The clinical and hematologic findings were consistent with HDN, despite repeatedly negative direct antiglobulin tests (DAT) on cord RBCs. Serologic investigations showed that the mother's serum contained anti-Mta. The father and all three children phenotyped as Mta+, while the mother was Mta-. Adsorption and elution experiments gave results which suggested that anti-Mta may be implicated in recurrent HDN in this family.

Journal Article↗
PubMed2001

Mutation in the beta-tubulin signature motif suppresses microtubule GTPase activity and dynamics, and slows mitosis.

We introduced a threonine-to-glycine point mutation at position 143 in the "tubulin signature motif" 140Gly-Gly-Gly-Thr-Gly-Ser-Gly146 of Saccharomyces cerevisiae beta-tubulin. In an electron diffraction model of the tubulin dimer, this sequence comes close to the phosphates of a guanine nucleotide bound in the beta-tubulin exchangeable E site. Both the GTP-binding affinity and the microtubule (MT)-dependent GTPase activity of tubulin isolated from haploid tub2-T143G mutant cells were reduced by at least 15-fold, compared to tubulin isolated from control wild-type cells. The growing and shortening dynamics of MTs assembled from alphabeta:Thr143Gly-mutated dimers were also strongly suppressed, compared to control MTs. The in vitro properties of the mutated MTs (slower growing and more stable) are consistent with the effects of the tub2-T143G mutation in haploid cells. The average length of MT spindles in large-budded mutant cells was only 3.7 +/- 0.2 microm, approximately half of the size of MT arrays in large-budded wild-type cells (average length = 7.1 +/- 0.4 microm), suggesting that there is a delay in mitosis in the mutant cells. There was also a higher proportion of large-budded cells with unsegregated nuclei in mutant cultures (30% versus 12% for wild-type cells), again suggesting such a delay. The results show that beta:Thr143 of the tubulin signature motif plays an important role in GTP binding and hydrolysis by the beta-tubulin E site and support the idea that tubulins belong to a family of proteins within the GTPase superfamily that are structurally distinct from the classic GTPases, such as EF-Tu and p21(ras). The data also suggest that MT dynamics are critical for MT function in yeast cells and that spindle MT assembly and disassembly could be coordinated with other cell-cycle events by regulating beta-tubulin GTPase activity.

Amino Acid Motifs↗
PubMed2001

Inactivation of human SRBC, located within the 11p15.5-p15.4 tumor suppressor region, in breast and lung cancers.

A cDNA clone encoding human SRBC [serum deprivation response factor (sdr)-related gene product that binds to c-kinase] was isolated in a yeast two-hybrid screening, with amino acids 1-304 of BRCA1 as the probe. The human SRBC gene (hSRBC) was mapped to chromosome region 11p15.5-p15.4, close to marker D11S1323, at which frequent loss of heterozygosity (LOH) has been observed in sporadic breast, lung, ovarian, and other types of adult cancers as well as childhood tumors. hSRBC-coding region mutations including frame shift and truncation mutations were detected in a few ovarian and lung cancer cell lines. More significantly, the expression of hSRBC protein was down-regulated in a large fraction [30 (70%) of 43] of breast, lung, and ovarian cancer cell lines, whereas strong expression of hSRBC protein was detected in normal mammary and lung epithelial cells. The down-regulation of hSRBC expression in cancer cells was associated with hypermethylation of CpG dinucleotides in its promoter region, and 3 (60%) of 5 primary breast tumors and 11 (79%) of 14 primary lung tumors were also found to be hypermethylated. Treatment of breast cancer MCF7 cells with 5'azacytidine and Trichostatin A resulted in expression of hSRBC, confirming DNA methylation as the mode of inactivation. Our results suggest that epigenetic or mutational inactivation of hSRBC may contribute to the pathogenesis of several types of human cancers, marking hSRBC as a candidate tumor suppressor gene.

Amino Acid Sequence↗