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Biomedical subjects

R N Smith

Publications and source records attributed to R N Smith.

At least 55 records · Page 3Linked to original sources
PubMed1995

Marketing the cosmetic practice via television.

Everyone is marketing their dental practice whether they know it or not. It is far better to design the desired effect than to send mixed messages to your clients. All marketing must be carried out with a plan or mission that is internalized by the doctor and by each member of the staff. The mission coupled with creative talent becomes the proprietary personality of your office and the focus of your marketing efforts. Internal marketing is perhaps the most economical and effective--and most used--method of creating positive results for the practice. External marketing takes your office out to the public most often in print via newsletters, direct mailings, and the yellow pages. Getting the message out through newspapers, radio, and television has and will become increasingly important. This article takes you through the steps we used to identify and market to our cosmetic clients. The results of our demographic and psychographic studies afford unique insight into the type of person attracted by our services. Marketing to this group has to do with diversity in appeal, "the boomers," and experiential motivation.

Adolescent↗
PubMed1995

Accurate size comparison of short tandem repeat alleles amplified by PCR.

A strategy is presented for classifying complex short tandem repeat (STR) alleles by size. Such alleles can differ in length by only 1 bp. The HUMACTBP2 locus was used as a model. Dye-labeled, PCR-amplified alleles were analyzed on an automated DNA sequencer with laser-induced fluorescence detection and fragment-sizing software. Between-gel allele sizes calculated against an in-lane allelic ladder or viral DNA size standard were too imprecise to distinguish a 1-bp difference. However, the size difference between a sample allele and its matching ladder allele provided a reliable criterion for size classification. The mean size difference +/- 3 SDs was 0.5 bp, and so an individual result within this interval signified a match. Statistically, 99.7% of the results should lie within +/- 3 SDs with virtually no chance of encountering the 9-SD difference from the mean necessary to misclassify an allele by 1 bp. The method was valid for sample alleles sized against the allelic ladder and for both sample and ladder alleles sized against the viral DNA standard. A correction for the effect of different dye labels on mobility was included in the calculations.

Alleles↗
PubMed1994

The symptomatology of progestogen intolerance.

It is common for women receiving oestrogen replacement therapy to experience adverse symptoms whilst taking cyclical progestogen. This study highlights the similarity of these symptoms to those experienced in pre-menstrual syndrome and confirms that the Moos Menstrual Distress Questionnaire is an appropriate tool for future research. The data also indicate that progestogens vary in the type of symptoms they cause. Norethisterone is more likely to cause symptoms from the Moos pain symptom cluster than either medroxyprogesterone or dydrogesterone, but is less likely to cause negative affect symptom cluster symptoms. The relative levels of oestrogen and progestogen may influence the severity of progestogenic symptoms.

Adult↗
PubMed1994

The dose-response of percutaneous oestradiol implants on the skeletons of postmenopausal women.

OBJECTIVE: To determine whether there is a dose-response effect of percutaneous oestradiol implants on the skeletons of postmenopausal women using a range of doses available in clinical practice. DESIGN: One year randomised study. SUBJECTS: Forty-five postmenopausal women who requested oestrogen replacement therapy were randomised to receive 25 mg, 50 mg, or 75 mg oestradiol implants. The bone mineral density changes were compared with a control group of 15 untreated women. MAIN OUTCOME MEASURES: Dual energy X-ray absorptiometry using Hologic 1000 QDR before treatment and after one year of treatment. Plasma oestradiol and follicle stimulating hormone levels before treatment and after one year. RESULTS: There were significant correlations between the plasma oestradiol levels and the percentage increase in bone density at the lumbar spine, the total hip, the femoral neck, and the trochanter. The median (range) plasma oestradiol level was 327 pmol/l (114-853) in the 25 mg group, 358 pmol/l (220-957) in the 50 mg group and 518 pmol/l (167-828) in the 75 mg group. Three women who lost a significant amount of bone from the clinically relevant sites in the 25 mg oestradiol group all had plasma oestradiol levels below 300 pmol/l. None of the women in either the 50 mg or 75 mg oestradiol groups lost bone from these sites. CONCLUSIONS: Oestradiol implants resulted in a wide range of circulating oestradiol levels with each of the doses used. There was a significant relation between plasma oestradiol levels and the increases in bone density at both the lumbar spine and the proximal femur. None of the women lost bone density at the clinically important sites of the spine and femoral neck if their plasma oestradiol levels were above 300 pmol/l.

Absorptiometry, Photon↗
PubMed1993

A massively parallel memory-based story system for psychotherapy.

We describe a memory-based system for psychotherapy, Dr. Bob, built to run on the data parallel processor Thinking Machines, Inc., CM-2a Connection Machine. The system retrieves, in parallel, stories of alcohol addiction and sexual abuse which can be used by psychiatrists in working with their patients as part of their work in recovering from addictive behavior and psychological trauma. The program is written in *LISP (pronounced Star LISP), a version of LISP used in programming Connection Machines.

Artificial Intelligence↗
PubMed1992

Multiple pathways in the rejection of skin grafts.

We have analyzed the ability of CD4+ and CD8+ T cells to cause rejection of skin grafts in an Ir gene high responder strain. (DA.RT1u x DA.RT1c)F1 B rats (thymectomized, lethally irradiated, reconstituted with fetal liver cells) were grafted with ear skin of the recombinant strain, DA.RT1rl. The only allogeneic difference was a single class I MHC antigen. The B rats, which do not reject these grafts due to the absence of T cells, were reconstituted at various time intervals after skin grafting with either unsorted lymph node cells (LNCs), CD4+, CD8+ or CD4+ and CD8+ T cells. Unsorted LNCs given any time after graft placement always caused rejection (MST = 15d). CD4+ cells alone never caused rejection (MST greater than 60d, n = 8). CD8+ cells alone caused rejection if given within 3 weeks of graft placement. Thereafter, CD8+ cells alone lost their ability to cause rejection (MST greater than 60d, n = 6). B rats with grafts in place more than 3 weeks, when CD8+ cells alone were ineffective, rejected their skin grafts when given both CD8+ and CD4+ cells. These data suggest that there may be two T cell pathways in skin graft rejection. The first requires only CD8+ cells and causes rejection of a recently placed graft. The second pathway requires both CD4+ and CD8+ cells to reject long-standing grafts in which donor antigen-presenting cells have been putatively depleted and, therefore, may be dependent on host antigen-presenting cells.

Animals↗
PubMed1991

Separation of electronic and hydrophobic effects for the papain hydrolysis of substituted N-benzoylglycine esters.

The role of hydrophobic and electronic effects on the kinetic constants kcat and Km for the papain hydrolysis of a series of 22 substituted N-benzoylglycine pyridyl esters was investigated. The series studied comprises a wide variety of substituents on the N-benzoyl ring, with about a 300,000-fold range in their hydrophobicities, and 2.1-fold range in their electronic Hammet constants (sigma). It was found that the variation in the log kcat and log 1/Km constants could be explained by the following quantitative-structure activity relationships (QSAR): log 1/Km = 0.40 pi 4 + 4.40 and log 1/kcat = 0.45 sigma + 0.18. The substituent constant, pi 4, is the hydrophobic parameter for the 4-N-benzoyl substituents. QSAR analysis of two smaller sets of glycine phenyl and methyl esters produced similar results. A clear separation of the substituent effects indicates that in the case of these particular esters, acylation appears to be the rate limiting catalytic step.

Catalysis↗
PubMed1991

Inhibition of intergeneric coaggregation among oral bacteria by cetylpyridinium chloride, chlorhexidine digluconate and octenidine dihydrochloride.

The potential inhibitory effect of chlorhexidine digluconate on the intergeneric coaggregation of 11 pairs of Gram-positive organisms was compared to its ability to inhibit coaggregations of 14 pairs comprised of both a Gram-positive and a Gram-negative cell type. Dramatic differences in the inhibitory effectiveness of the antimicrobial compound on the two kinds of coaggregation pairs were found. Gram-positive pairs were not inhibited at a concentration of 0.25%, whereas the coaggregations involving a Gram-negative partner were usually completely blocked at concentrations as low as 0.01%. Similar effects to chlorhexidine digluconate were found with octenidine dihydrochloride and cetylpyridinium chloride, while sodium dodecylsulfate was inhibitory only at 10- to 50-fold higher concentrations. These results suggest that chlorhexidine digluconate, octenidine dihydrochloride, and cetylpyridinium chloride may be effective inhibitors of later microbial colonizers of dental plaque but may not disturb a normal healthy indigenous flora.

Actinomyces↗
PubMed1991

The safety and tolerability of sumatriptan: an overview.

Safety information was pooled from 4,859 patients, mainly treated in controlled clinical trials with a dispersible tablet of sumatriptan or by a subcutaneous injection, and from 1,164 patients who received placebo by these routes. Safety monitoring involved collection of all adverse events, regardless of their relationship to treatment, and included routine laboratory screening tests and some special investigations. Individuals experienced several groups of symptoms that might be considered to be features of migraine itself or of the post-migraine period or due to treatment. The commonest complaints were an unpleasant taste or pain on injection. After oral sumatriptan (100-300 mg), some events (nausea, malaise) were characteristic of migraine and others (fatigue, sedation, weakness) were characteristic of the recovery period. With subcutaneous sumatriptan (4-8 mg) similar events were observed, but certain distinctive symptoms variously described as heaviness, pressure sensation, tingling, feelings of heat or warmth, were more common and affected various parts of the body. Their early onset and transient nature suggests some pharmacological mechanism, as yet not identified. Despite the mixed picture of symptoms recorded after treatment, they were not serious, they were transient and they were accepted by patients. Close patient monitoring allowed detailed evaluation of any possible cardiovascular side-effects as seen with other anti-migraine agents, particularly ergotamine. The evidence is reassuring but, since experience in patients with symptomatic ischaemic heart disease is limited, it is recommended that they should initially be treated with sumatriptan under medical supervision for their first two or three attacks.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Evaluation of a commercial radioimmunoassay kit for the detection of lysergide (LSD) in serum, whole blood, urine and stomach contents.

The Diagnostic Products Corporation Coat-A-Count radioimmunoassay kit for LSD in urine has been evaluated for use in forensic toxicology with a variety of sample types. The cut-offs (defined as the mean response of blank samples plus three standard deviation) for LSD in serum, haemolysed whole blood, urine and stomach contents were 0.06, 0.050-0.055, 0.18 and 0.18 ng/ml, respectively. Preliminary extraction of LSD from the samples is not usually necessary. The precision of the analysis and the recoveries from spiked samples were satisfactory. The cross-reactivities of 2-oxo-LSD, lysergic acid methyl propylamide, lysergic acid monoethylamide and nor-LSD were estimated to be 11,6,2 and 1% respectively relative to LSD (100%).

Calibration↗
PubMed1990

Aberrant radioimmunoassay results for cannabinoids in urine.

False negative and false positive radioimmunoassay results for cannabinoids in urine are reported. Such results occur infrequently and appear to be due to non-specific binding of the radiolabel by interfering substances, possibly proteins, in the specimens. False negatives arise when these substances and the non-specifically bound radiolabel are precipitated by polyethylene glycol in the separation stage of the assay, increasing the radioactivity in the bound fraction and thus lowering the assay result. False positives occur when the interfering substances and non-specifically bound radiolabel remain in solution during the separation stage, increasing the radioactivity in the free fraction and giving an erroneously high result. False positives could also occur in assays involving solid-phase antibodies or second-antibody separations. Methanol treatment of the samples prior to analysis precipitates the interfering substances and eliminates the aberrant effect. The interfering substances have not been identified through common serum proteins and semen have been excluded. No common factor in the circumstances of the cases that can account for the results has been identified.

Adolescent↗
PubMed1990

Gas chromatographic-mass spectrometric confirmation of radioimmunoassay results for cannabinoids in blood and urine.

A simple gas chromatographic-mass spectrometric (GC-MS) method is described for the detection of 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (delta 9-THC-COOH) in blood and urine samples found to be positive by two in-house cannabinoid radioimmunoassays (RIAs). The delta 9-THC-COOH in the samples, which is partly present as its glucuronide conjugate, is isolated by solvent extraction after hydrolysis of the glucuronide. It is converted to its trimethylsilyl derivative and analysed by capillary GC-MS in the electron impact mode with selected ion recording. All samples that were positive by both RIAs were also positive by GC-MS apart from four blood and two urine samples in which the GC-MS results were inconclusive owing to the presence of coextractives. No sample that was positive by both RIAs was found to be negative by GC-MS.

Cannabinoids↗