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Biomedical subjects

J Stanton

Publications and source records attributed to J Stanton.

At least 37 records · Page 2Linked to original sources
PubMed1996

Digital pressure during interscalene block is clinically ineffective in preventing anesthetic spread to the cervical plexus.

The application of digital pressure above the injection site during interscalene block has been advocated to prevent cephalad spread of local anesthetic. In prior studies, radiographs taken immediately after interscalene injection of radiographic contrast have supported this concept. However, the clinical efficacy of digital pressure has not been previously tested. If digital pressure were effective in inhibiting cephalad spread of local anesthetic, attenuation of both hemidiaphragmatic paresis and the resulting compromise in pulmonary function would be expected. Sensory, motor, and pulmonary effects were prospectively evaluated in 20 patients presenting for elective shoulder surgery. Patients were randomly assigned to receive interscalene block with or without digital pressure. No clinical differences were seen between groups. All 20 patients had ipsilateral hemidiaphragmatic paresis by ultrasonographic evaluation and large mean decreases in forced vital capacity, 31.2% +/- 7.8% (with digital pressure), 33.7% +/- 12.8% (without digital pressure), and forced expiratory volume at one second, 27.9% +/- 9.3% (with digital pressure), 33.7 +/- 12.8% (without digital pressure). Peak sensory level of anesthesia to pinprick was not significantly different between groups, each group having mean levels of C-2 to C-3. Digital pressure was ineffective in limiting the flow of local anesthetic into the cervical plexus. Digital pressure influenced neither the incidence of diaphragmatic paresis nor the resulting large decreases in pulmonary function that result from interscalene block.

Adolescent↗
PubMed1995

Combined spinal-epidural anesthesia for outpatient surgery. Dose-response characteristics of intrathecal isobaric lidocaine using a 27-gauge Whitacre spinal needle.

BACKGROUND: Combined spinal-epidural anesthesia (CSE) may offer theoretic advantages for outpatient surgery, because it produces the rapid onset of spinal anesthesia, with the option to extend the blockade with an epidural catheter. In this study, the authors attempted to determine an appropriate initial dose of a short-acting local anesthetic, 2% lidocaine, to administer for outpatient knee arthroscopy using CSE. METHODS: Data were collected from 90 patients undergoing outpatient knee arthroscopy. Using a double-blinded, prospective study design, patients were randomly assigned to receive CSE with an initial dose of intrathecal 2% lidocaine of 40, 60, or 80 mg. A 27-G 4 11/16-inch Whitacre needle was placed through a 17-G Weiss needle. Onset and regression of sensory anesthesia and motor blockade were measured by a blinded observer at frequent intervals. RESULTS: All 90 patients had adequate anesthesia. Durations of thoracic and lumbar sensory and lower limb motor blockade were significantly shorter in the 40-mg group compared with the 60- or 80-mg groups (P < 0.0002 Mantel-Cox, Survivorship Analysis). Indices of neural blockade resolved 30-40 min more rapidly in the 40-mg group than in either the 60- or 80-mg group. Times to urinate, site upright in a chair, take oral fluids, and be discharged were all significantly shorter (between 30 and 60 min) in the 40-mg group compared with the 60- and 80-mg groups (P < 0.01). Seven patients required intraoperative epidural supplementation: three in the 40-mg group, three in the 60-mg group, and one in the 80-mg group. CONCLUSIONS: Combined spinal-epidural anesthesia with a 40-mg initial intrathecal dose of lidocaine provided reliable anesthesia for knee arthroscopy. Duration of spinal anesthesia with lidocaine was dose related.

Adolescent↗
PubMed1995

It's about time.

Explore the source record for details and available documents.

Continuity of Patient Care↗
PubMed1995

Contradictions in British vaccine policy on hepatitis B.

A vaccine for hepatitis B became available in the UK from 1982, but it did not solve the public health dilemmas presented by the disease. In the decade that followed, epidemiologically important groups such as intravenous drug users and gay men were not targetted, while the groups of health workers at the centre of policy concern received little vaccine. This paper draws on models of diffusion, the pattern of the disease, and previous policies on screening, to explain the restricted vaccine policy which was a field for contention through the 1980s and into the 1990s.

Adult↗
PubMed1994

Identification of a receptor-binding region in the core segment of the human anaphylatoxin C5a.

In order to identify regions of C5a that contribute to receptor binding and functional activity of the anaphylatoxin, a series of peptides was synthesized in which core segments have been attached to C-terminal segments via native peptidic or disulfide bonds. It has been found that residues Arg40 and Arg46 in the loop-3 region of the core induce a 1000-fold increase in the affinity of the disordered C-terminal segment of C5a. The results obtained from this work lead to the conclusion that the loop-3 region is most likely the core binding site of C5a.

Amino Acid Sequence↗
PubMed1994

Low, but strongly structured mitochondrial DNA diversity in root knot nematodes (Meloidogyne).

Root-knot nematodes (genus Meloidogyne) have been the subject of recent and numerous studies of genetic variation because of the need to develop molecular diagnostics for the four globally distributed, parthenogenetic species that are significant agricultural pests. Our analysis of Meloidogyne mtDNA improves on previous studies: (i) by examining restriction site polymorphism among a large number of isolates also characterized for standard morphological, host range and allozyme phenotypes; (ii) by using higher resolution electrophoretic techniques; and (iii) by mapping variable restriction sites with reference to the complete nucleotide sequence. This revealed fivefold less sequence divergence (< 0.6%) between variants than estimated in previous restriction fragment length polymorphism (RFLP) studies, but perfect correspondence between mtDNA haplotype and allozyme (esterase) phenotypes. The mtDNA variation, although limited, is strongly structured with as much divergence between two lineages of Meloidogyne arenaria as between either of these and Meloidogyne javanica. The low diversity of mtDNAs suggests that these parthenogenetic lineages arose from distinct but closely related sexual females, a pattern seen in other parthenogenetic complexes. In contrast to the concordance between mtDNA and allozyme markers, there were several discrepancies between the traditional methods of identification. We suggest that further studies of these nematodes should focus on well defined genetic groups, whether or not these coincide with existing taxonomic units.

Animals↗
PubMed1994

What shapes vaccine policy? The case of hepatitis B in the UK.

Comparison of hepatitis B vaccine policy with other cases in the past is complicated by the restricted modes of transmission of this disease, which affects relatively few people in the UK. Still, considerations of cost, fear of contamination, divisions of opinion within the medical profession, and regional dispersal of authority are all factors--analysed for other vaccines--which help to explain the limited UK central policy on hepatitis B immunization observed through the 1980s. An important issue, in previous debates on vaccine policies, has been the conflict between public health interests and the rights of individuals to eschew health interventions imposed by the state. It is argued here that this question fed into hepatitis B vaccine policy in an oblique manner, via policy on screening for hepatitis B in the 1970s; minimal screening mainly of selected groups of health workers was favoured, maximizing individual rights. Changes to hepatitis B vaccine policy can be traced, linked with international policy, pharmaceutical company pressure, advances in vaccine technology, and questions of legal liability. The most accurate predictor for vaccine policy appears to have been screening policy. Will this apply to AIDS, which is epidemiologically similar to hepatitis B?

Health Policy↗
PubMed1994

Single versus staged epidural injections of 0.75% bupivacaine: pharmacokinetic and pharmacodynamic effects.

Epidural anesthesia may be performed as a single injection or by staged doses. Thirty patients undergoing primary total hip replacement were randomly assigned to have epidural anesthesia using a single injection or a staged technique with 25 mL of 0.75% bupivacaine. Arterial plasma bupivacaine concentrations were significantly higher in the single injection group for the first 15 min but were not significantly different thereafter. Peak bupivacaine concentrations did not differ significantly between groups, but the time to achieve the peak concentration was delayed by staging injections (P = 0.001). Hemodynamic effects were similar between groups. Resolution of thoracic sensory block through T12 and duration of motor block measured by Bromage scale were both significantly longer in the staged injection group (P < 0.01). The method of epidural injection may affect resolution of neural block and the time to reach peak arterial plasma concentration of local anesthetic.

Anesthesia Recovery Period↗
PubMed1993

Protection of DNA from high LET radiation by two OH radical scavengers, tris (hydroxymethyl) aminomethane and 2-mercaptoethanol.

The effect of high linear energy transfer (LET) radiation on DNA in vitro, both in protective and non-protective environments was investigated. Two hydroxyl radical scavengers, tris(hydroxymethyl) aminomethane and 2-mercaptoethanol, were compared for their ability to protect SV40 DNA from radiation damage over a wide LET range. At comparable OH scavenging capacities, significant differences were found between these protective agents, indicating that other, radical scavenger-dependent processes affected the extent to which the DNA was protected. In general, a decrease in single-strand breaks (SSBs) relative to double-strand breaks (DSBs) was observed as LET increased. This effect was more pronounced when a radioprotector was present. Comparison of the relative biological efficiency (RBE) of radiation damage as LET increased showed a peak of DSB production in the mid-LET range. These data agree with measurements made by Christensen et al. (1972). An explanation for this increase in DSB production efficiency has been proposed based on the particle track structure of high-LET radiation.

DNA Damage↗
PubMed1992

Novel 5-HT3 antagonists: indol-3-ylspiro(azabicycloalkane-3,5'(4'H)-oxazoles).

The synthesis and biochemical evaluation of a series of spirofused indole oxazoline 5-HT3 antagonists is described in which the oxazoline ring acts as a bioisosteric replacement for esters and amides. The effect of substitution about the indole ring has shown the steric limitations of the aromatic binding site. Incorporation of a variety of azabicyclic systems within the rigid spirofused framework has allowed the definition of a binding model which incorporates a number of known antagonists and agonists. In this model steric constraints limit substitution around the indole ring although there is some bulk tolerance at the 1- and 2-positions. The importance of constraining the basic nitrogen within an azabicyclic system is underlined by comparison with the monocyclic piperidine. The highest affinity was observed for those compounds in which the basic nitrogen occupies a bridgehead position, the most potent analogue in this group being the azabicyclic [3.3.1] system (pIC50 = 8.95), suggesting lipophilic interactions may play a role in increasing affinity. A suggested model for agonist binding is included in which the basic nitrogens are superimposed and the 5-hydroxyl group of 5-HT is superimposed on the H-bond-accepting atom of the heterocyclic linking group.

Animals↗
PubMed1992

Clinical experience with patient administered subcutaneous dihydroergotamine mesylate in refractory headaches.

This study examines the practicality and efficacy of dihydroergotamine mesylate (DHE) when self-administered subcutaneously in a population of refractory headache patients. Forty-three patients with chronic daily headache or migraine headache without aura, who had been taught self-injection of DHE either through the Raskin Protocol or in an outpatient headache clinic, were contacted by telephone and administered a questionnaire regarding usage and results from DHE injection. Ninety-two percent of patients could successfully administer DHE. Forty-six percent of patients experienced 90% or greater relief of pain and the majority of patients (77%) had greater than 50% relief. Emergency room use was decreased in 83% and 80% preferred DHE to their previous therapy. While side effects were common (79%), only four patients (9%) stopped DHE for this reason. No convincing evidence for the development of rebound headaches due to DHE was found in this sample.

Adult↗
PubMed1992

The development of a support group organization for headache sufferers.

People with a wide variety of problems use support groups. We describe the development, structure and current functioning of a support group organization for headache sufferers, which has grown from ten members to 300 in four years. About one-half of the members participate in ten currently functioning support groups. In addition to these support groups, the organization plays an active role in the community by sponsoring public awareness seminars, publishing a quarterly newsletter, providing emergency treatment cards, and making knowledgeable speakers available to local business groups. The membership has been described by means of a questionnaire. Information regarding medical history, impact of headaches on everyday functioning, and involvement with the organization is presented. Future directions of the organization are discussed.

Colorado↗
PubMed1992

In-house recruiters: new role needs clear direction to benefit.

Physician recruiters are fast becoming part of the hospital's personnel arsenal. But how do administrators use these positions within the confines of their institution and when do they hire outside consultants to do the work or at least, supervise it? In the following article, the author discusses how to effectively formulate and utilize such a position in the hospital.

Consultants↗
PubMed1991

Novel 5-HT3 antagonists. Indole oxadiazoles.

The synthesis and biochemical evaluation of a series of indole oxadiazole 5-HT3 antagonists are described. The key pharmacophoric elements have been defined as a basic nitrogen, a linking group capable of H-bonding interactions, and an aromatic moiety. The steric limitations of the aromatic binding site have been determined by substitution about the indole ring. Variation of the heterocyclic linking group has shown that while two hydrogen-bonding interactions are possible, only one is essential for high affinity. The environment of the basic nitrogen has been investigated and shown to be optimal when constrained within an azabicyclic system. These results have been incorporated into a proposed binding model for the 5-HT3 antagonist binding site, in which the optimum distance between the aromatic binding site and the basic amine is 8.4-8.9 A and the steric limitations are defined by van der Waals difference mapping.

Animals↗