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Biomedical subjects

G Gardner

Publications and source records attributed to G Gardner.

At least 37 records · Page 2Linked to original sources
PubMed1998

Host spatial heterogeneity and extinction of an SIS epidemic.

Spatially explicit epidemic models explore population-level consequences of interactions between neighboring infectious and susceptible individuals. Most such models equate local and global host density, so that each individual interacts with the same number of neighbors. But many natural populations exhibit heterogeneity in local abundance. Therefore, we let host dispersion vary from uniform to clumped in a spatial epidemic with recovery. We analytically approximated the epidemic with a branching process to show how the probability of pathogen extinction could depend on the degree of host clumping. We then simulated the detailed model across a range of parameter combinations. Both approaches to the problem indicate that host spatial aggregation strongly increases the chance of pathogen extinction.

Animals↗
PubMed1998

Assessing outcomes for dysphonic patients.

This study was designed to evaluate a disease-specific outcome measure for patients with selected voice disorders and to relate this instrument to a standardized quality of life measurement. In addition, the study attempts to document the degree of handicap for dysphonia patients globally, between different vocal pathologies, and in comparison to other chronic diseases. In this prospective, observational study, 260 adult patients evaluated for alterations of voice completed a general quality of life measure (the Medical Outcomes Trust Short Form 36-Item[SF-36]) and a voice-specific instrument (Voice Handicap Index [VHI]) pretreatment. The highest correlation was between the social functioning score of the SF-36 and the total score of the VHI and the physical, emotional, and functional subscales (p < 0.001) of the VHI. Significant correlation was also obtained for the SF-36 domains mental health (p < 0.01), general health (p < 0.01), and role functioning emotional (p < 0.017) with the three VHI domains and the total VHI score. Patients had significantly lower scores than the general U.S. population in five of the eight domains of SF-36. Patients with vocal fold paralysis had the highest level of pretreatment disability as measured on both the VHI and SF-36 among voice patients. The patients with dysphonia had a lower level of physical functioning than the patients with chronic sinusitis (p < 0.01), reflecting a greater handicap. In addition, the dysphonia group had lower levels of social functioning than the angina (p < 0.01) and sciatica (p < 0.01) groups and a lower score for mental health than the angina group (p < 0.01). The SF-36 correlates with the VHI in the domains of social functioning, mental health, and role functioning emotional. The baseline handicap for voice disorders represents a significant disability even in comparison to conditions such as angina pectoris, sciatica, and chronic sinusitis.

Adolescent↗
PubMed1998

The human dimension of nosocomial wound infection: a study in liminality.

Nosocomial wound infection is a disease that has to date been primarily understood through the language of science and biomedicine. This paper reports on findings from a sociological, interpretive study that focused on the experiential dimension of this phenomenon. The illness experience of a nosocomial wound infection is examined within a cultural milieu that values the smooth, untroubled body and alternatively ascribes cultural meaning to a body that has a definable illness. Within this context the person with a chronic wound from nosocomial infection defies normative categorisation and is thus situated outside the patterning of society. The human dimension of nosocomial wound infection includes the private, existential and embodied aspects of living with a chronic, infected wound. This report indicates that the experiential dimension is characterised by an embodied state of liminality. People with this illness live an indeterminate existence that is in-between health and illness, cure and disease. As such they have no recognised place in the medical or social world.

Adaptation, Psychological↗
PubMed1998

Evidence that the phytochrome gene family in black cottonwood has one PHYA locus and two PHYB loci but lacks members of the PHYC/F and PHYE subfamilies.

The phytochrome photoreceptors play important roles in the photoperiodic control of vegetative bud set, growth cessation, dormancy induction, and cold-hardiness in trees. Interestingly, ecotypic differences in photoperiodic responses are observed in many temperate-zone tree species. Northern and southern ecotypes of black cottonwood (Populus trichocarpa Torr. & Gray), for example, exhibit marked differences in the timing of short-day-induced bud set and growth cessation, and these responses are controlled by phytochrome. Therefore, as a first step toward determining the molecular genetic basis of photoperiodic ecotypes in trees, we characterized the phytochrome gene (PHY) family in black cottonwood. We recovered fragments of one PHYA and two PHYB using PCR-based cloning and by screening a genomic library. Results from Southern analyses confirmed that black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum) suggest that the PHYB/D duplications in these species occurred independently. When Southern blots were probed with PHYC, PHYE, and PHYE heterologous probes, the strongest bands that we detected were those of black cottonwood PHYA and/or PHYB. These results suggest that black cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black cottonwood could contain additional PHY that are distantly related to known angiosperm PHY, our results imply that the PHY family of black cottonwood is less complex than that of other well-characterized dicot species such as Arabidopsis and tomato. Based on Southern analyses of five black cottonwood genotypes representing three photoperiodic ecotypes, substantial polymorphism was detected for at least one of the PHYB loci but not for the PHYA locus. The novel character of the PHY family in black cottonwood, as well as the differences in polymorphism we observed between the PHYA and PHYB subfamilies, indicates that a number of fundamental macro- and microevolutionary questions remain to be answered about the PHY family in dicots.

Amino Acid Sequence↗
PubMed1998

The dose-response relationship of ketorolac as a component of intravenous regional anesthesia with lidocaine.

UNLABELLED: Ketorolac (K) is a useful addition to lidocaine for i.v. regional anesthesia (IVRA). However, the minimal dose of K that is effective for this purpose has not been established. We added 0, 5, 10, 15, 20, 30, and 60 mg of K to 0.5% lidocaine IVRA for either carpal tunnel release or tenolysis. Pain was assessed in the postanesthesia care unit by using a visual analog scale. The duration of analgesia (time to first request for pain relief) and the use of Tylenol No. 3 tablets (T3) were measured. A linear dose-response relationship was observed between the dose of K and the duration of analgesia (r = 0.988) up to 20 mg of K. Similarly, the number of T3 tablets used was inversely related to the dose of K (r = 0.960) over the same range. There were no significant differences among the groups who received 20, 30, or 60 mg of K. We conclude that 20 mg of K is the optimal dose for inclusion with 0.5% lidocaine for IVRA under the conditions of our study. IMPLICATIONS: The antiinflammatory drug ketorolac is a useful addition to lidocaine for i.v. regional anesthesia. This study showed that 20 mg of ketorolac is equally effective as 60 mg in this context. However, smaller doses provided less effective pain relief, and a linear dose-response relationship was demonstrated.

Acetaminophen↗
PubMed1997

Image-interactive orientation in the middle cranial fossa approach to the internal auditory canal: an experimental study.

Approaches through the middle cranial fossa directed at reaching the internal auditory canal (IAC) invariably employ exposure of the geniculate ganglion, the superior semicircular canal (SSC) or the epitympanum. This involves risk to the facial nerve and hearing apparatus. To minimize this risk, we conducted a laboratory study on 9 cadaver temporal bones by using an image-interactive guidance system (StealthStation) to provide topographic orientation in the middle fossa approach. Surface anatomic fiducials such as the umbo of the tympanic membrane, Henle's spine, the root of the zygoma and various sutures were used as fiducials for registration of CT-images of the temporal bone. Accurate localization of the IAC was achieved in every specimen. Mean target localization error varied from 1.20 to 1.38 mm for critical structures in the temporal bone such as the apex of the cochlea, crus commune, ampula of the SSC and facial hiatus. Our results suggest that frameless stereotaxy may be used as an alternative to current methods in localizing the IAC in patients with small vestibular schwannomas or intractable vertigo undergoing middle fossa surgery.

Cadaver↗
PubMed1997

Predictors of physician frustration in the care of patients with rheumatological complaints.

Recent studies of the doctor-patient relationship have shown that certain patients are perceived as frustrating or difficult by their doctors; however, little is known about the characteristics of these patients that elicit this dissatisfaction. As part of a larger study of rheumatology clinic patients with fibromyalgia or rheumatoid arthritis (N = 68) we used stepwise multiple regression to select the factors most associated with physician frustration while controlling for the effects of other variables. Variable domains included demographics, psychiatric diagnoses, personality factors, functional disability, disease state, and trauma history. These domains as well as individual variables within these domains were systematically evaluated for their unique contribution to the prediction of physician frustration as measured by the Difficult Doctor-Patient Relationship Questionnaire (DDPRQ). Initial bivariate correlates of physician frustration included marital status, current dysthymia and agoraphobia, lifetime panic disorder and obsessive-compulsive disorder, adult rape and physical abuse, somatization disorder, physical and social disability, the presence of fibromyalgia, as well as neuroticism, illness impact, and perceived loss of control. The best multivariable model for estimating frustration magnitude included somatization disorder, perception of lack of control over illness, and a lifetime history of obsessive-compulsive disorder. These factors explained 48% of the variance in DDPRQ score. Physicians in this study were most frustrated with patients who had ongoing preoccupation with multiple medically unexplained physical symptoms as well as the perception of greater impact and lack of control over their illness. These findings suggest that treatment of somatization in patients with chronic symptoms may decrease physician frustration.

Adult↗
PubMed1997

An accurate, cost-effective approach for diagnosing retrocochlear lesions utilizing the T2-weighted, fast-spin echo magnetic resonance imaging scan.

Recent data indicate that the auditory brainstem response (ABR) fails to identify a significant number of retrocochlear lesions. Although the magnetic resonance imaging (MRI) scan with paramagnetic enhancement is highly accurate at detecting these lesions, it is time consuming and expensive. We report on our prospective evaluation of a cohort of 155 patients who underwent T2-weighted, fast-spin echo MRI scans designed to screen for retrocochlear lesions. This imaging technique is rapidly performed and provides superb visualization of the relevant anatomic structures at a global cost of $475. Four tumors were identified with this technique. Cost analysis indicates that supplanting ABR with this limited MRI may well represent a cost-effective approach for evaluating patients with suspected retrocochlear lesions.

Cochlea↗
PubMed1996

The nurse researcher: an added dimension to qualitative research methodology.

Nurse researchers are increasingly adopting qualitative methodologies for research practice and theory development. These approaches to research are, in many cases, more appropriate for the field of nursing inquiry than the previously dominant techno-rational methods. However, there remains the issue of adapting methodologies developed in other academic disciplines to the nursing research context. This paper draws upon my own experience with interpretive research to raise questions about the issue of nursing research within a social science research framework. The paper argues that by integrating the characteristics of nursing practice with the characteristics of research practice, the researcher can develop a 'nursing lens', an approach to qualitative research that brings an added dimension to social science methodologies in the nursing research context. Attention is drawn to the unique nature of the nurse-patient relationship, and the ways in which this aspect of nursing practice can enhance nursing research. Examples are given from interview transcripts to support this position.

Humans↗
PubMed1996

Cholesterol granulomas of the petrous apex: combined neurosurgical and otological management.

Cholesterol granulomas of the head are relatively rare. Isolated lesions of the cerebellopontine angle are even more uncommon. In this report, 17 cases of petrous apex cholesterol granulomas are presented and management is discussed. Symptoms at presentation included dizziness (14 patients), pressure (nine patients), tinnitus (eight patients), hearing loss (eight patients), otalgia (six patients), headache (six patients), nausea (three patients), drainage from ear (two patients), facial pain (two patients), seizure (two patients), lightheadedness (one patient), hemifacial spasm (one patient), and facial numbness (one patient). Six cases were managed without surgery and 11 patients underwent operative procedures. The approaches used included the infralabyrinthine (eight patients), transcanal-infracochlear (two patients), and translabyrinthine (one patient). The mean follow-up period for all cases was 29.5 months. Of those patients managed without surgery, symptoms improved in all except one, whose tinnitus was slightly worse. Of surgically treated patients, symptoms improved or remained the same except in one with worsened dizziness. There were nine patients with hearing present presurgery and seven whose hearing was preserved postsurgery. The authors present a case that was managed at another center where an attempt at surgical resection through a subtemporal middle fossa approach was unsuccessful. This lesion was successfully treated using an infralabyrinthine approach with drainage into the mastoid cavity. Cholesterol granulomas of the petrous apex can be managed without surgery when symptoms are stable or improve. Otherwise, a transmastoid extradural approach with simple drainage into the mastoid sinus or middle ear produces symptomatic improvement with low morbidity. Resection of petrous apex cholesterol granulomas is not necessary.

Adolescent↗