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Biomedical subjects

S Woodward

Publications and source records attributed to S Woodward.

At least 37 records · Page 2Linked to original sources
PubMed1994

The thermoregulatory effects of menopausal hot flashes on sleep.

Menopausal hot flashes are thought to be a disorder of thermoregulation initiated centrally within the medial preoptic area of the hypothalamus. These heat-loss mechanisms appear to be activated in the presence of normal core body temperature. Previous studies have demonstrated that thermal stimuli have the potential to alter sleep stages. We performed 24-hour ambulatory recordings of hot flashes and all-night sleep parameters on 12 postmenopausal women with hot flashes and seven postmenopausal women without flashes to determine whether the presence of hot flashes prior to sleep or during sleep itself would result in alterations in sleep pattern. The results show that hot flashes are associated with increased Stage 4 sleep and a shortened first rapid eye movement period. Hot flashes occurring in the 2 hours prior to sleep onset were positively correlated with the amount of slow-wave sleep. The central thermoregulatory mechanism underlying hot flashes may affect hypnogenic pathways inducing sleep and heat loss in the absence of a thermal load.

Body Temperature Regulation↗
PubMed1994

Effects of publicity and a warning letter on illegal cigarette sales to minors.

The study aimed to assess rates of illegal cigarette sales to children and the impact on these rates of publicity and a warning letter threatening prosecution. Children aged 12 and 13 made two repeat purchasing attempts, three months apart, at 255 randomly selected tobacco retail outlets in Sydney. A randomly selected 50 per cent of retail outlets which sold cigarettes illegally at the first attempt were sent warning letters threatening prosecution. Publicity about the undercover buying operation was organised between the attempts. At the first attempts, 39 per cent of shops sold cigarettes to the children and 32 per cent sold them at the second attempt. Shops which sold on the first occasion and received warning letters reduced selling by 69 per cent compared to the 40 per cent reduction in shops which sold cigarettes on the first attempt and were not sent warning letters, a net reduction of 29 per cent seemingly attributable to the warning letters (95 per cent confidence interval 8 per cent to 50 per cent). It is extremely easy for children as young as 12 to buy cigarettes. The combined effects of publicity about undercover buying operations and warning letters threatening prosecution seem capable of reducing selling by about 29 per cent. Because of inconsistencies in selling or refusals, future attempts to measure selling rates to children should use repeat purchasing attempts and classify outlets as 'selling', 'not selling' or 'sometimes selling'.

Adolescent↗
PubMed1994

Nonneural mediation of digital vasodilation during menopausal hot flushes.

Menopausal hot flushes are accompanied by profuse sweating, decreased skin resistance, modest tachycardia and cutaneous vasodilation. With the exception of the last effect, these events are consistent with an abrupt increase in sympathetic outflow. Blood flow in the human finger is controlled through sympathetic vasoconstricting nerves, and increased sympathetic activation results in digital vasoconstriction. We therefore sought to determine if digital vasodilation during hot flushes was mediated through efferent sympathetic nerves. Bilateral finger temperature and blood flow were recorded after the digital nerves on one hand had been blocked with a local injection of lidocaine. The effectiveness of the nerve blocks was verified by a reflex vasoconstriction test. Hot flushes were objectively defined using skin conductance responses recorded from the sternum. Fifteen hot flushes occurred in 8 women. Significant elevations in finger temperature and blood flow occurred during the flushes, in nerve-blocked and intact fingers. These findings suggest that digital vasodilation during hot flushes is due to a circulating vasodilating substance.

Adult↗
PubMed1993

Heterobasidion annosum 5.8s ribosomal DNA and internal transcribed spacer sequence: rapid identification of European intersterility groups by ribosomal DNA restriction polymorphism.

Using conserved fungal ribosomal gene sequences the internal transcribed spacer (ITS) regions one and two (ITS1, ITS2) and the 5.8s ribosomal RNA gene (rRNA) of Heterobasidion annosum were amplified by the polymerase chain reaction (PCR). The nucleotide sequence was determined in three European intersterility groups (ISG-S, -F and -P). Three sequence variants of the ITS were found in ISG-S isolates. The sequence of the ITS of ISG-F differed by two residues from the major ISG-S sequence variant. The ISG-P sequence differed from ISG-S and ISG-F at 15-16 and 16 residues, respectively. Amplified intergenic spacer elements were informative for ISG fingerprinting following digestion with various 4-cutter restriction endonucleases. All differences in the restriction fragments between the ISGs were because of sequence differences in the ITS regions. The fingerprint patterns of isolates from the same intersterility group but from different European localities were identical. These results show that ribosomal DNA fingerprinting is a rapid technique to identify ISGs in Heterobasidion annosum.

Base Sequence↗
PubMed1993

Fostering a change in policy. HIV, AIDS and the neuroscience nurse.

As new treatments and drug therapies enable the control of opportunistic diseases associated with Aids, its neurological manifestations are becoming more prevalent. This poses new challenges to neuroscience nurses, who must reassess their attitude to and understanding of the disease.

AIDS Dementia Complex↗
PubMed1992

A molecular model for membrane fusion based on solution studies of an amphiphilic peptide from HIV gp41.

The mechanism of protein-mediated membrane fusion and lysis has been investigated by solution-state studies of the effects of peptides on liposomes. A peptide (SI) corresponding to a highly amphiphilic C-terminal segment from the envelope protein (gp41) of the human immunodeficiency virus (HIV) was synthesized and tested for its ability to cause lipid membranes to fuse together (fusion) or to break open (lysis). These effects were compared to those produced by the lytic and fusogenic peptide from bee venom, melittin. Other properties studied included the changes in visible absorbance and mean particle size, and the secondary structure of peptides as judged by CD spectroscopy. Taken together, the observations suggest that protein-mediated membrane fusion is dependent not only on hydrophobic and electrostatic forces but also on the spatial arrangement of the amino acid residues to form an amphiphilic structure that promotes the mixing of the lipids between membranes. A speculative molecular model is proposed for membrane fusion by alpha-helical peptides, and its relationship to the forces involved in protein-membrane interactions is discussed.

Amino Acid Sequence↗
PubMed1992

Behavioral treatment of menopausal hot flushes: evaluation by ambulatory monitoring.

OBJECTIVES: We attempted to develop an effective behavioral treatment for menopausal hot flushes and to determine the active behavioral components of this procedure. STUDY DESIGN: Thirty-three women with frequent menopausal hot flushes were randomly assigned to receive eight sessions of training in paced respiration, muscle relaxation, or alpha-wave electroencephalographic biofeedback (placebo control). Hot flushes were objectively measured by means of 24-hour ambulatory monitoring of the sternal skin conductance level. RESULTS: Subjects undergoing paced respiration had significant reductions in hot flush frequency and respiration rate, as well as increases in tidal volume. CONCLUSION: Paced respiration training may be a useful treatment alternative for the reduction of hot flushes in women who cannot tolerate hormone replacement therapy.

Ambulatory Care↗
PubMed1992

Use of suppressor analysis to identify DNA polymerase mutations in herpes simplex virus which affect deoxynucleoside triphosphate substrate specificity.

Herpes simplex virus DNA polymerase mutations which map in the N-terminal part of the protein and appear to alter deoxynucleoside triphosphate (dNTP) substrate specificity are described. These mutations suppress a drug hypersensitivity associated with the downstream mutation, Aphr10. We suggest that the mutant residues form part of the dNTP-binding site, a site previously thought to be confined to the C terminus.

Aphidicolin↗
PubMed1991

Pathophysiologic effects of biliary shockwave lithotripsy in a canine model.

At least 10 extracorporeal shockwave lithotripters are under investigation in the United States for treatment of biliary stone disease. Few reports, however, have documented the potential side effects of this new treatment method. In this study, we performed a series of acute and chronic studies in dogs exposed to varying numbers of shockwaves directed at the gallbladder wall via a transthoracic or transabdominal targeting approach. When shockwaves were directed transthoracically, pulmonary hemorrhagic contusions were found which were sometimes large in size. When a transabdominal approach was used, however, only focal areas of hemorrhage were found in the gallbladder wall and adjacent liver with no alterations in postlithotripsy pancreatic or liver enzymes, and normal cholecystokinin-octapeptide stimulated oral cholecystograms were obtained 6 days after treatment. Biliary shockwaves appear to cause few side effects under normal conditions but should be used with caution in patients with potential bleeding disorders. Until further studies are performed, lung tissue should be avoided in the shockwave beam path during treatment.

Abdomen↗
PubMed1990

Genetic analysis of an inherited predisposition to colon cancer in a family with a variable number of adenomatous polyps.

We studied a large kindred with a history of colorectal cancer of early onset. Proctosigmoidoscopic examination of 51 family members identified only 2 with familial polyposis coli, which strongly predisposes those who have it to colorectal cancer and which is defined as the presence of more than 100 polyps in the colon. However, eight family members had 2 to 40 colonic polyps. We suspected that in this family, colorectal cancer was the result of a mutation in the gene on chromosome 5 that is responsible for familial polyposis coli. To test our hypothesis, we obtained genotypic information on 81 family members with respect to seven polymorphic DNA markers previously shown to be linked to the locus for familial polyposis coli. Multilocus analysis of the data demonstrated genetic linkage (lod score, 5.58) between these markers and the locus responsible for the defined syndrome of colonic polyps or colorectal cancer in this kindred. These findings constitute evidence that the genetic defect in this family is a mutation in the gene that causes familial polyposis coli. We conclude that mutations at the genetic locus for familial polyposis coli may be the cause of other, more subtle syndromes involving an inherited susceptibility to colonic adenomatous polyps and colorectal cancer.

Adenomatous Polyposis Coli↗
PubMed1990

Frequency variation in spontaneous sound emissions from guinea pig and human ears.

Spontaneous acoustic emissions were recorded from 7 of 15 human ears at frequencies between 900 and 4000 Hz and just above 1000 Hz in a guinea pig. The constancy or changes in the frequency composition of these emissions is of particular interest in the light of current models which implicate outer hair cell activity in their generation. In our present study, most emissions underwent continuous fluctuations in frequency over a bandwidth of 0.5-10 Hz in humans and more than 20 Hz in a young guinea pig. Jumps in frequency of emission by as much as 20 Hz occurred during test sessions in some of the human ears. Changes in emission frequency were also observed during suppression by an externally delivered tone. The frequency of the emissions at successive test sessions also varied in some human ears and in the guinea pig between the ages of 6 and 9 weeks. The guinea pig emission also underwent an increase of 50 Hz in frequency and a reduction of 25 dB in level during recovery from anaesthesia. Neely's model for the role of hair cells in the generation of spontaneous emissions suggests that changes in hair cell conductance could influence the frequency of spontaneous oscillation. The small, but continuous changes in spontaneous emission frequency seen in all ears may reflect changes in conductance at the hair cell level due to synaptic and transducer channel activity.

Aging↗
PubMed1990

Effects of otolithic vestibular stimulation on sleep.

This study evaluated the effects of otolithic vestibular stimulation in the form of a linearly accelerated parallel swing on nighttime sleep parameters and daytime sleep tendency in eight normal subjects. The protocol consisted of one adaptation night following by two motion nights, one adaptation night followed by two stationary nights, and two Multiple Sleep Latency Tests (MSLT), one motion and one stationary. On the motion nights, there was a decrease in stage 2 percentage as well as a facilitative effect on sleep latency on the last night. In addition, an increase in the number of rapid eye movements (REMs) per night was found without a significant alteration of REM sleep amount or latency. No significant differences were found between the motion and stationary MSLT days.

Adaptation, Physiological↗
PubMed1990

Why the tobacco industry fears the passive smoking issue.

The tobacco industry has identified the passive smoking issue as the single most important problem confronting its economic future. During the 1980s, the industry has been engaged in an elaborate and expensive international campaign seeking to refute the evidence against passive smoking's effects on health and to position the issue as one essentially concerned with civil liberties and smokers' "rights." There are three main reasons for the industry's concern: first, the passive smoking issue allows a widening of the definition of smoking beyond its discussion as a personal habit, legitimizing it as a social problem; second, successful cases of litigation against employers by workers with histories of chronic exposure to environmental tobacco smoke have created an industrial climate of concern leading to workplace smoking restrictions and bans, and third, the proliferation of smoking restrictions reduces smoking opportunities and thus reduces total cigarette consumption and hence financial returns to the industry. Based on the results of a large Australian study of a workplace smoking ban, an estimated 654.88 million cigarettes with a retail value of $A6,549 thousand would be forgone annually in Australia alone if 50 percent of white-collar worksites were to ban smoking. Finally, the passive smoking issue can be considered a Trojan horse to its less discussed effects: the reduced morbidity and mortality likely to result in smokers from the significant reductions in smoking frequency that occur with the proliferation of smoking restrictions introduced in the name of concern for the health of nonsmokers.

Commerce↗
PubMed1990

Alpha 2-adrenergic mechanism in menopausal hot flushes.

It has been hypothesized that hot flushes are triggered within the hypothalamus by alpha 2-adrenergic receptors on noradrenergic neurons. We administered intravenous clonidine (an alpha 2-adrenergic agonist) and yohimbine (an alpha 2-adrenergic antagonist) to nine menopausal women with hot flushes and to an asymptomatic comparison group. Hot flushes were defined objectively by skin conductance responses recorded from the sternum; finger temperature recordings and symptom reports were also evaluated. The subjects were prescreened using ambulatory skin conductance monitoring. A significantly greater number of hot flushes occurred during yohimbine sessions than in corresponding placebo sessions (six versus zero). Clonidine significantly increased the amount of peripheral heating needed to provoke a hot flush (40.6 versus 33.6 minutes) and reduced the number of hot flushes that did occur (two versus eight). No hot flushes occurred in the asymptomatic women. These findings support the role of a central alpha 2-adrenergic mechanism in the initiation of hot flushes.

Adult↗