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Biomedical subjects

I J Russell

Publications and source records attributed to I J Russell.

At least 73 records · Page 4Linked to original sources
PubMed1990

A comparison of two methods for facilitating clinical data integration by medical students.

Two important charting strategies to help students organize patients' data are Weed's problem-oriented medical record (POMR) and Russell's condition diagram (CD). The authors conducted the present study in 1987 to determine whether either was superior for clinical data integration. Sophomore medical students at The University of Texas Medical School at San Antonio indicated whether they preferred the POMR, the CD, or neither. They were then divided into three study groups according to their preferences, with the POMR and CD groups receiving 80 hours of training and the control group receiving only the standard preclinical training. Each student then examined a standardized patient and wrote an open-ended report about the patient's medical problem. After examining a second patient, students were asked to write a structured report providing information about each of ten components of diagnosis. Both the CD and the POMR groups scored numerically higher on the structured type of report than did the controls, but only the CD group scored significantly higher. The CD group also scored higher than did the POMR group on both types of report, but the differences were not statistically significant. This study indicates that the clinical reasoning of medical students can be enhanced by focused training in either the CD or the POMR methods. It suggests that the CD format may be particularly helpful for students with lower academic achievement.

Algorithms↗
PubMed1990

Lesser metatarsalgia. Rheumatologic considerations.

The differential diagnosis for metatarsalgia should include rheumatoid arthritis, SLE, mixed connective tissue disease, psoriatic arthritis, Reiter's syndrome, fibromyalgic syndrome, gout, post-traumatic joint disease, and septic arthritis. When the patient's symptoms are approached systematically an accurate diagnosis can lead to implementation of an appropriate treatment plan. Multidisciplinary treatment approaches often lead to the most satisfying therapeutic outcomes.

Foot Diseases↗
PubMed1990

Psychological stress and the fibrositis/fibromyalgia syndrome.

The relationship of stress and social support to the fibrositis/fibromyalgia syndrome (FS) was investigated by administration of 4 questionnaire instruments to 28 patients with FS, 20 patients with rheumatoid arthritis (RA) and 28 pain-free normal controls. FS showed higher levels of stress as measured by daily "hassles" than did RA or controls. However, on a measure of major life stress, they reported lower levels. No differences were found between groups with regard to daily "uplifts" or social support. Correlations between those measures of stress and social support with their scores on the Arthritis Impact Measurement Scale showed that the Hassles Scale was significantly related to the AIMS Psychological component.

Arthritis, Rheumatoid↗
PubMed1989

Development and initial validation of a dual-language English-Spanish format for the Arthritis Impact Measurement Scales.

Language, cultural, and educational barriers complicate efforts to validate health status questionnaires that have been translated into Spanish. To overcome these problems, a prototype dual-language format was developed for the Arthritis Impact Measurement Scales. Validity testing with 72 patients diagnosed as having rheumatoid arthritis indicated high levels of test-retest reliability, item-to-scale internal consistency, and construct validity for both Anglo and Hispanic subjects. A technique for developing and pilot-testing a questionnaire written in a regional Spanish dialect is described. Linguistic considerations, questionnaire design, and other applications are discussed in light of the results obtained.

Arthritis↗
PubMed1989

The responses of cochlear hair cells to tonic displacements of the sensory hair bundle.

Hair bundle displacements and receptor potentials were recorded from outer hair cells (OHCs) in organotypic cultures of the mouse cochlea during force steps applied to the bundles with a silica probe of known stiffness. The receptor potentials of some OHCs adapt for excitatory displacements and the time constants of receptor potential adaptation and hair bundle force relaxation for excitatory displacements are very similar. Thus in these OHCs, the receptor potentials correspond to the applied force for excitatory displacements. For inhibitory displacements, the receptor potentials correspond to hair bundle displacement. Some OHC receptor potentials are nonadapting and follow displacement in both the excitatory and inhibitory directions. The hair bundles of nonadapting OHCs are less stiff than those of adapting OHCs and nonadapting OHCs are an order of magnitude less sensitive to hair bundle displacement than adapting OHCs. In response to a combination of excitatory, tonic, hair bundle displacement and current injection, the receptor potentials of nonadapting OHCs decline as the membrane potential is made more positive and reverse near 0 mV. When the receptor potentials of adapting OHCs measured during current injection are compensated for constant input resistance and driving voltage across the transducer conductance, the receptor potential amplitude at the offset of the step displacement is independent of the level and polarity of the injected current. Before adaptation, at the onset of the step displacement of the hair bundle, the amplitude of the receptor potential increases as the injected current becomes more positive. For adapting OHCs, the receptor potential amplitude is a linear function of excitatory bundle displacement for amplitudes less than 50 nm. With negative, but not positive, current injection the receptor potentials at the onset of the displacement tend to saturate and the slope of the function decreases. This voltage dependent control of OHC transducer operating range is proposed to have a role in regulating the sensitivity of the cochlea.

Adaptation, Physiological↗
PubMed1989

Stereociliary bundle morphology in organotypic cultures of the mouse cochlea.

Organotypic cultures of the neonatal mouse cochlea have a band of hair cells consisting of 3-5 rows of outer hair cells and a single row of inner hair cells. The outer hair cell stereociliary bundles show progressive differentiation from the apical to the basal ends of the band. Undifferentiated apical bundles have a disk-like array of short stereocilia resembling microvilli. Partially differentiated bundles are hemispherical with poorly organized rows of thickly clustered stereocilia, which gradually increase in height in the direction of the kinocilium. More differentiated bundles remain hemispherical with many microvilli-like stereocilia, but have highly organized rows of sterocilia along the side nearest to the kinocilium, and well-defined height increments between the rows. Highly-differentiated, basal bundles usually have a 'V' or 'W' shape, although some can be almost polygonal. The basal bundles have 4-5 regular rows of stereocilia with a well-defined gradient in height across the rows, and very few microvilli-like stereocilia. Cross-links are only consistently observed in more differentiated bundles, where the rows of stereocilia are regular and have significant height increments across them. The links show a wide variety of forms and orientations not previously observed in other preparations. Spoke-like arrays of links project from the upper regions of many stereocilia and other stereocilia appear to bear distinct tip-to-side links, although with a variety of orientations. A similar variety of cross-links is observed in early postnatal cochleae in vivo, but not in the cochleae of adult mice, indicating that this variety may be a transient feature of sterociliary bundle development. In vitro, inner hair cell stereociliary bundles are often covered by overlying material from the developing tectorial membrane. The variations in morphology of inner hair cell bundles and their cross-links are similar to those of the outer hair cell bundles.

Animals↗
PubMed1989

An approach to developing a valid Spanish language translation of a health-status questionnaire.

This article discusses methodological issues confronting health professionals using questionnaires to study health care variables among populations with limited literacy in English, and suggests techniques for minimizing problems that plague questionnaire-based research among these populations. A recent effort to validate a questionnaire for Rheumatoid Arthritis patients in South Texas is used to illustrate pitfalls and potential solutions.

Arthritis, Rheumatoid↗
PubMed1989

Serum amino acids in fibrositis/fibromyalgia syndrome.

Free plasma tryptophan levels in patients with fibrositis syndrome were measured by Moldofsky and Warsh with the view that the pathogenesis of fibrositis syndrome might involve a functional deficiency of serotonin. The hypothesis was supported by the finding of an inverse relationship between tryptophan concentration and the severity of musculoskeletal pain. Our study examined the total serum amino acid pool in fibrositis syndrome. Twenty patients with primary fibrositis syndrome and matched normal controls were evaluated clinically. After denaturation of macromolecules, serum amino acids were quantitated by automated analysis. Patients with fibrositis syndrome exhibited significantly lower levels of total serum tryptophan (p = 0.002), as well as 6 other amino acids: alanine (p less than 0.0005), histidine (p = 0.001), lysine (p = 0.02), proline (p = 0.039), serine (p = 0.028), and threonine (p = 0.013). These findings support the serotonin deficiency hypothesis for fibrositis syndrome pathogenesis but also imply a more generalized defect in amino acid homeostasis among affected individuals.

Amino Acids↗
PubMed1989

Neurohormonal aspects of fibromyalgia syndrome.

There is a growing awareness that fibrositis/fibromyalgia syndrome is a systemic disorder for which a pathogenic mechanism must be sought. A generalized deficiency of the neurotransmitter, serotonin could explain many of fibromyalgia's typical manifestations. The serotonin deficiency hypothesis is appealing because it provides a number of experimental approaches that can now be used to further study the pathogenesis of this disorder.

Animals↗
PubMed1988

Acoustically induced hearing loss: intracellular studies in the guinea pig cochlea.

Intracellular recordings were made from both inner and outer hair cells (IHC, OHC) in the basal coil of the guinea pig cochlea before, during and after the animal was exposed to loud, pure tones. Following multiple loud tones both types of sensory cells demonstrate a culmulative decrease in their voltage responses to a test tone. A loss in sensitivity of the compound action potential (CAP) of the eighth nerve co-incides with a decrease in both the amplitude of the IHC receptor potential and the positive summating potential (+SP) recorded at the round window. The largest decreases in sensitivity of IHCs are found at the characteristic or best frequency (CF) of each cell and this frequency selective loss of sensitivity results in a decrease in the tuning of the hair cell. During and following a loud tone the nonlinear properties of IHCs are also reduced.

Action Potentials↗
PubMed1987

Polypeptide composition of the mammalian tectorial membrane.

The effects of the enzymes collagenase, pepsin, chondroitinase ABC and keratanase on the polypeptide composition of the mammalian tectorial membrane have been analysed using one dimensional SDS-polyacrylamide gel electrophoresis (SDS-PAGE). After reduction at least ten polypeptides can be consistently and clearly recognized in SDS gels with molecular weights relative to globular protein standards of 245, 235, 190, 165, 155, 145, 100, 93, 60-73 and 35-49 kDa. With the exception of the 60-73 and 35-49 kDa bands all these polypeptides are sensitive to digestion with bacterial collagenase. The 235, 165, 155, 145 and 93 kDa bands also resist degradation by cold, acidic pepsin. Amino acid analysis of whole tectorial membranes demonstrates that glycine accounts for nearly 25% of the total amino acid content, that proline, hydroxyproline and hydroxylysine are present and that amine sugars can be detected in fairly high concentrations. Estimates based on hydroxyproline content suggest that collagens account for 25-50% of the total tectorial membrane protein. Immunoblotting techniques demonstrate the presence of polypeptides cross reacting with antisera to Type II collagen, Type IX collagen and Type V collagen. Results from immunohistochemical studies confirm that these polypeptides are present in the tectorial membrane and are not contaminants of the isolation procedure. Collagenase treatment of tectorial membranes reveals the presence of an additional non-collagenous polypeptide with an apparent molecular weight of 173 kDa on 7.5% polyacrylamide gels, and polydisperse high molecular weight material spreading over a broad range at the top of the gels. This high molecular weight material and the 173, 60-73 and 35-49 kDa non-collagenous polypeptides are pepsin sensitive and all bind wheat germ agglutinin (WGA) suggesting that they contain N-acetyl glucosamine. The 173 kDa band also binds soybean agglutinin (SBA) suggesting the presence of N-acetyl galactosamine. In the absence of reducing agent the 173 and 60-73 kDa bands are no longer observed and high molecular weight material forming a broad band at the top of the separating gel is seen. The electrophoretic behaviour of this non-collagenous, glycosylated, disulphide bonded, high molecular weight material is altered by treatment with keratanase but not by chondroitinase ABC. The results of this study indicate the tectorial membrane contains at least three different collagen types and, in addition to these collagenous proteins, several non-collagenous, glycosylated polypeptides that may account for as much as 50% of the total tectorial membrane protein.

Acetylgalactosamine↗
PubMed1987

The morphology and physiology of hair cells in organotypic cultures of the mouse cochlea.

Organotypic explant cultures were prepared from the cochleas of 1 to 3 day post-natal mice and maintained in vitro for up to 5 days. The hair cells retain morphological integrity for the duration of the culture period although they exhibit embryological features such as a kinocilium and additional microvilli on their apical surfaces. The resting membrane potentials of mouse inner hair cells (IHCs) in vitro are similar to those of guinea-pig IHCs in vivo but the membrane potentials of outer hair cells (OHCs) in the mouse cochlea in vitro are less polarized than the resting membrane potentials of OHCs in the basal turn of the guinea-pig cochlea in vivo. The voltage responses of IHCs and OHCs to sinusoidal displacements of their stereocilia are similar to each other in waveform and dynamic range, although the responses of IHCs are larger than those of OHCs. The relationship between transducer conductance and stereocilia displacement in IHCs and OHCs is non-linear and largely accounts for the depolarizing asymmetry of the voltage response. The receptor potentials of IHCs and OHCs reverse close to 0 mV indicating that the transducer conductance is non-selective for cations. The voltage responses of IHCs and OHCs to intracellular current injection rectify when the membrane potentials are more depolarized than about -30 mV. This rectification is most pronounced in OHCs. OHCs also exhibit a time-dependent, voltage-sensitive conductance although they do not behave as electrical resonators.

Animals↗
PubMed1987

The response of hair cells in the basal turn of the guinea-pig cochlea to tones.

1. Intracellular recordings were made from inner and outer hair cells in the basal turn of the guinea-pig cochlea. The resting membrane potentials of the inner hair cells are more positive than -50 mV while those of outer hair cells are usually more negative than -70 mV. 2. At low frequencies the receptor potentials of inner hair cells are predominantly depolarizing while those from outer hair cells are hyperpolarizing at low and moderate sound pressure (e.g. less than 90 dB re 2 X 10(-5) Pa at 600 Hz). The potentials then become predominantly depolarizing at high sound pressure. 3. The asymmetry of the inner and outer hair cell receptor potentials are manifested instantaneously except at high stimulus levels when the depolarizing responses of outer hair cells take several cycles to develop. 4. At the offset of intense tones outer hair cell membrane potentials remain depolarized by 1-2 mV above their resting value and return to normal over a period depending on the level and duration of the tone. 5. In response to tones above about 2 kHz and at levels below about 90 dB the wave forms of outer hair cell receptor potentials are virtually symmetrical without measurable d.c. components. In response to tones close to their best frequencies (16-21 kHz), inner hair cells in the basal turn generate large depolarizing (d.c.) receptor potentials while outer hair cells from this region of the cochlea do not generate significant voltage responses. 6. Frequency tuning curves were derived for inner and outer hair cells from the amplitude-intensity relationships of their d.c. and phasic (a.c.) receptor potentials respectively. When the latter were compensated for the low-pass characteristics of the recording system and the hair cell time constant, the frequency selectivity of inner and outer hair cells are similar. 7. The response properties of inner and outer hair cells in the basal turn of the guinea-pig cochlea are discussed in relation to their proposed roles in mechano-electric transduction.

Acoustic Stimulation↗
PubMed1986

Is there a metabolic basis for the fibrositis syndrome?

Patients with the fibrositis syndrome experience moderately severe musculoskeletal discomfort, mood changes associated with nonrestorative sleep, and tenderness to palpation at specific body sites. There is no characteristic abnormal laboratory finding in these patients to help identify the population. A report by Moldofsky and Warsh (Pain 1978; 5: 65-71) of low serum levels of free tryptophan in patients with severe fibrositis syndrome is intriguing but remains unexplained. Those data plus the observation by Hudson et al (Am J Psychiatry 1985; 142: 441-446; Biol Psychiatry 1984; 19: 1489-1493) that patients with fibrositis syndrome exhibit an increased prevalence of anxiety and depression suggest a number of possible avenues for further study. They include potential alterations in the homeostasis of catecholamines, corticosteroids, serotonin, aromatic amino acids, platelet membrane receptor levels, and the activity of platelet membrane monoamine oxidase. Among these possibilities, evidence is now available that suggests an increased production of catecholamines in fibrositis syndrome.

Animals↗
PubMed1986

Auranofin therapy and quality of life in patients with rheumatoid arthritis. Results of a multicenter trial.

In a six-month, randomized, double-blind study at 14 centers, auranofin (3 mg twice daily) was compared with placebo in the treatment of patients with classic or definite rheumatoid arthritis. All patients had unremitting disease for at least the previous six months and at least three months of therapy with nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs, oral steroids, and analgesics were allowed throughout the trial. Efficacy was analyzed in 154 patients who received auranofin and 149 who received placebo. To reflect an expanded view of outcome assessment, the measures used included some 20 nontraditional measures of functional performance, pain, global impression, and utility (worth or value) in addition to five standard clinical measures of rheumatoid synovitis (e.g., number of tender joints). The nontraditional measures were mainly in the form of structured questionnaires administered by trained interviewers. To minimize the statistical problem of multiple comparisons, most of the measures were grouped into four composites--clinical (standard measures), functional, global, and pain--and the treatment effect for each composite was tested at the 0.0125 level of significance. Auranofin was superior to placebo in the clinical (p = 0.003), functional (p = 0.001), and global (p = 0.007) composites and trended similarly in the pain composite (p = 0.021). Individual measures within the composites consistently favored auranofin. Other measures, not part of the composites, also favored auranofin, including a patient utility measure designed for this study, the PUMS (p = 0.002). Results confirm the hypothesis that the favorable effect of auranofin on clinical synovitis is accompanied by improvements across a range of outcomes relevant to the patient's quality of life.

Adult↗
PubMed1986

Phase-locking in the cochlear nerve of the guinea-pig and its relation to the receptor potential of inner hair-cells.

The high-frequency limit of phase-locking has been measured in fibres of the auditory nerve in the guinea-pig. It is shown that phase-locking begins to decline at about 600 Hz and is no longer detectable above 3.5 kHz which is about 1 octave lower than in the cat, squirrel monkey and some birds. Direct measurements of the cochlear afferent fibre synaptic delay are consistent with indirect estimates from phase-locking, both giving values of 0.7-0.8 ms. Measurements of the receptor potentials of inner hair-cells in the guinea pig cochlea indicate that as the stimulus frequency is increased there is a progressive decrease in the a.c. component compared to the steady depolarization. The cause of this decline is the low-pass filtering of the a.c. component by the hair-cell membrane. The cut-off and slope of the decline in the a.c. component is consistent with the suggestion that this process is the limiting factor in cochlear nerve fibre phase-locking. The implications of these findings for interspecies variation in phase-locking cut-off, for cochlear mechanisms and for the encoding of complex sounds are discussed.

Acoustic Stimulation↗