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Biomedical subjects

S Phillips

Publications and source records attributed to S Phillips.

At least 55 records · Page 3Linked to original sources
PubMed1999

Impact of HIV type 1 subtype variation on viral RNA quantitation.

We evaluated the performance of three HIV-1 RNA quantitation methods (Amplicor HIV-1 MONITOR-1.0, NASBA, and Quantiplex HIV RNA 2.0 [branched DNA (bDNA)]) using plasma specimens (N = 60) from individuals from Asia and Africa infected with one of three HIV-1 subtypes (A, Thai B [B'] or E; N = 20 each). Our results demonstrate that of the 20 subtype A specimens, 19 were quantifiable by the bDNA assay compared with 15 by the MONITOR-1.0 and 13 by NASBA. Of those quantifiable, the mean log10 difference was 0.93 between bDNA and MONITOR-1.0 and 0.46 between bDNA and NASBA. For subtype B' specimens, the correlation among methods was better with only 2 specimens missed by NASBA and 3 by the bDNA assay. However the missed specimens had viral burden near the lower limit (1000 copies/ml) for these assays. For the 20 subtype E specimens, MONITOR-1.0 and NASBA quantified RNA in 17 and 14 specimens, respectively, as compared with 19 specimens quantified by the bDNA assay. The correlation among different assays, especially between bDNA/NASBA and MONITOR-1.0/NASBA, was poor, although the mean log10 difference for subtype E specimens was 0.4 between bDNA and MONITOR-1.0 and only 0.08 between bDNA and NASBA. The addition of a new primer set, designed for non-B HIV-1 subtypes, to the existing MONITOR assay (MONITOR-1.0+) resulted in RNA detection in all 60 specimens and significantly improved the efficiency of quantitation for subtypes A and E. Our data indicate that HIV-1 subtype variation can have a major influence on viral load quantitation by different methods. Periodic evaluation and modification of these quantitative methods may be necessary to ensure reliable quantification of divergent viruses.

Cote d'Ivoire↗
PubMed1999

Alkylfurans: effects of alkyl side-chain length on insecticidal activity.

The insecticidal activity of five alkylfurans against the generalist insect herbivore beet armyworm, Spodoptera exigua, was examined. Two naturally occurring compounds, the avocadofurans 2-(pentadecyl)furan (1) and 2-(heptadecyl)furan (2), previously isolated from specialized avocado idioblast oil cells, and three homologues, 2-(tetradecyl)furan (3), 2-(hexadecyl)furan (4), and 2-(octadecyl)furan (5), were synthesized. Bioassays of alkylfurans 1-5 using a 9-day diet-incorporation initiated with neonates showed that all alkylfurans tested significantly increased S. exigua larval mortality and reduced larval weights, with maximal biological activity detected among the naturally occurring alkylfurans 1 and 2.

Animals↗
PubMed1999

Analysis of the sequence of dioscorea Alata bacilliform virus: comparison to others members of the badnavirus group.

The complete nucleotide sequence of the genome of Dioscorea alata bacilliform virus (DaBV) has been determined from cloned fragments. Features of the genome confirm DaBV to be a pararetrovirus of the genus Badnavirus which is more similar to other mealy-bug transmitted badnaviruses, in particular to cacao swollen shoot virus, than to rice tungro bacilliform virus. Sequence variability between cloned fragments suggests that the genetic variability of the virus may be quite high (up to 11% nucleotide sequence variation for some small regions of the genome) although the overall variability detected was 4.2% at the nucleotide level.

Badnavirus↗
PubMed1999

Novel, non-radioactive, simple and multiplex PCR-cRFLP methods for genotyping human SP-A and SP-D marker alleles.

We have previously identified an allele of the human SP-A2 gene that occurs with greater frequency in an RDS population [12]. Because of the importance of SP-A in normal lung function and its newly emerging role in innate host defense and regulation of inflammatory processes, we wish to better characterize genotypes of both SP-A1 and SP-A2 genes. It has been determined that SP-D shares similar roles in immune response. Therefore, in this report we 1) describe a novel, non radioactive PCR based-cRFLP method for genotyping both SP-A and SP-D; 2) describe two previously unpublished biallelic polymorphisms within the SP-D gene; 3) present the partial sequence of one new SP-A1 allele (6A14) and describe other new SP-A1 and SP-A2 alleles; and 4) describe additional methodologies for SP-A genotype assessment. The ability to more accurately and efficiently genotype samples from individuals with various pulmonary diseases will facilitate population and family based association studies. Genetic polymorphisms may be identified that partially explain individual disease susceptibility and/or treatment effectiveness.

Alleles↗
PubMed1999

Ultrashort laser pulse bioeffects and safety.

Recent studies of retinal damage due to ultrashort laser pulses have shown that less energy is required for retinal damage for pulses shorter than 1 ns than that for longer pulses. It has also been shown that more energy is required for near-infrared (NIR) wavelengths than in the visible because the light focuses behind the retina, requiring more energy to produce a damaging fluence on the retina. We review the progress made in determining the trends in retinal damage from laser pulses of 1 ns to 100 fs in the visible and NIR wavelength regimes. We have determined the most likely damage mechanism(s) operative in this pulse width regime.

Animals↗
PubMed1999

Oklahoma physician needs.

State policy makers, healthcare professionals, and advocates have been asking various iterations of the question, Do we have too many or too few physicians? In order to address this question, a relative-needs analysis was conducted for the state of Oklahoma. Six projection-needs studies were used for comparison with Oklahoma's supply of practicing physicians. This analysis found that Oklahoma did not have a surplus of primary care physicians. While the national average for primary care physicians per 100,000 was 79, Oklahoma's ratio was 68. This analysis also compares not only the number of physicians in Oklahoma per 100,000 population, it also discusses the proportion of primary care physicians in the physician workforce. Primary care physicians were found to be neither oversupplied nor undersupplied in Oklahoma. Oklahoma was found to be closer to national planning model goals than most states in the United States. Because this study combines both allopathic and osteopathic physicians and includes only those physicians in active practice, it is unique in comparison to many other studies concerning physician workforce needs.

Family Practice↗
PubMed1998

Genomic structure and domain organisation of the human Bak gene.

The Bcl-2 homologue, Bak, is a potent inducer of apoptosis. FISH data presented here located the gene to 6p21.3. Mapping was consistent with its location centromeric of the HSET locus and approximately 400kb from the MHC. The construction of a contig of genomic clones across the locus facilitated the sequencing of a PAC containing the gene. Comparison of the gene structure to functional and physical domains revealed a good agreement between the physical structure and the intron-exon organisation. The position of a single intron was conserved in comparison to other members of the Bcl-2 family, namely Bax, CED-9, Bcl-X and Bcl-2, but all other introns were displaced, consistent with a divergent phylogeny.

Amino Acid Sequence↗
PubMed1998

An investigation into the effects of nicotine gum on short-term memory.

Using a between-subjects 2x2x2 factorial design, 60 smokers and 60 non-smokers (equal number of males and females) performed a short-term memory task requiring delayed free recall of a visually presented supraspan word list. Using a double-blind procedure, half the subjects chewed nicotine gum and the other half chewed placebo gum prior to performing the memory task. Results support previous research findings which show that nicotine significantly improves short-term memory. Sex differences were also investigated, but findings showed no significant differences between male and female subjects. Methodological considerations are discussed and directions for future research are suggested.

Adolescent↗
PubMed1998

Processing capacity defined by relational complexity: implications for comparative, developmental, and cognitive psychology.

Working memory limits are best defined in terms of the complexity of the relations that can be processed in parallel. Complexity is defined as the number of related dimensions or sources of variation. A binary relation has one argument and one source of variation; its argument can be instantiated in only one way at a time. A binary relation has two arguments, two sources of variation, and two instantiations, and so on. Dimensionality is related to the number of chunks, because both attributes on dimensions and chunks are independent units of information of arbitrary size. Studies of working memory limits suggest that there is a soft limit corresponding to the parallel processing of one quaternary relation. More complex concepts are processed by "segmentation" or "conceptual chunking." In segmentation, tasks are broken into components that do not exceed processing capacity and can be processed serially. In conceptual chunking, representations are "collapsed" to reduce their dimensionality and hence their processing load, but at the cost of making some relational information inaccessible. Neural net models of relational representations show that relations with more arguments have a higher computational cost that coincides with experimental findings on higher processing loads in humans. Relational complexity is related to processing load in reasoning and sentence comprehension and can distinguish between the capacities of higher species. The complexity of relations processed by children increases with age. Implications for neural net models and theories of cognition and cognitive development are discussed.

Cognition↗
PubMed1998

Relation between neurological status, refractive error, and visual acuity in children: a clinical study.

The aims of the present study were: (1) to determine the refractive status and visual acuity of a group of 75 neurologically impaired children (5 to 192 months of age); and (2) to investigate the relation between the visual and neurological status of these children. Refractive error was determined using non-cycloplegic near retinoscopy and visual acuity was estimated using acuity cards (Keeler or Cardiff) and pattern-onset visual evoked potentials (VEP). Subjects demonstrated a markedly different distribution of refractive error from that of a neurologically normal age-matched population. Refractive error anomalies were more prevalent in children older than 5 years, suggesting abnormal refractive development. A wide range of visual acuity was found with both tests (acuity cards, 0.07 to 2.08 logMAR; VEP, O.78 to 2.68 logMAR). Visual acuity and refractive status varied with level and type of physical impairment. Level of intellectual impairment exhibited a weak relation with visual status.

Adolescent↗
PubMed1998

Pediatricians' pet peeves about mental health referrals.

This chapter has described a number of problems encountered by pediatricians when referring their patients for mental health services; these are related to access to care, quality of providers and service, attitudes of patients and providers, and lack of adequate communication. We have discussed some of the reasons for these difficulties, provided information that may assist pediatricians in making referrals to appropriate mental health providers, and offered suggestions to facilitate the referral process. We have highlighted the utility of developing and maintaining a relationship with mental health referral sources, and noted a number of advantages of including mental health providers in pediatric practices.

Adolescent↗
PubMed1998

Prospective randomized controlled trial comparing Lichtenstein with modified Bassini repair of inguinal hernia.

We present a prospective randomized study of 80 patients with inguinal hernia who underwent either a modified Bassini repair (n = 38) or a Lichtenstein mesh repair (n = 42). Treatment groups were matched for age, side of hernia, type of hernia and ASA grade. There was no difference in the time taken to perform the two operations: the mean time taken to perform Lichtenstein repair was 26.8 min (range 12 to 49), Bassini repair taking a mean of 27.5 min (range 9 to 51), P = 0.76. There was, however, a difference between the operating times with respect to the type of hernia present, direct hernias being the fastest to repair. Pain scores were assessed by a visual analogue scale, and there was significantly less pain in the Lichtenstein group, P = 0.028. Despite this, there was no difference between the analgesic requirements of the two groups, P = 0.073. In order to assess rehabilitation, lengths of time not working and not driving were assessed. There was no difference in either measurement, P = 0.335 and 0.467 respectively. Patients were followed up a mean of 7 weeks post-operatively (range 1 to 13 weeks). There was no significant difference between the two procedures with regard to post-operative urinary complications, wound infection or other complications. All measurements except the time taken to perform the operation were independent of the surgeon involved. The accuracy of the clinical diagnosis was also assessed, and found to be moderate, with 63% of diagnoses being correct.

Adolescent↗
PubMed1997

Obstructive sleep apnoea: diagnosis and management.

Snoring and the associated syndrome of sleep apnoea can have severe effects on the lives of sufferers and their families. This article discusses why obstructive sleep apnoea is potentially fatal, and how it may be identified and managed.

Causality↗