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Biomedical subjects

E W Johnson

Publications and source records attributed to E W Johnson.

At least 55 records · Page 3Linked to original sources
PubMed1994

Olfaction and endoscopic sinus surgery.

Recent advances in endoscopic evaluation of the nose and paranasal sinuses and endoscopic sinus surgery, coupled with the development of standardized testing of olfactory acuity, have permitted improved correction of olfactory dysfunction. Conversely, increase in the number of operations performed has increased the number of injuries to the olfactory pathways. The mechanisms of loss and potential preventive and corrective measures are reviewed with a goal to minimize the numbers of these complications.

Endoscopy↗
PubMed1993

Effect of multiple risk factors on differences between blacks and whites in the prevalence of non-insulin-dependent diabetes mellitus in the United States.

The higher prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in US blacks as compared with whites may be due to a higher frequency of NIDDM risk factors in blacks, a higher inherent susceptibility to NIDDM among blacks, or the risk factors' having a greater effect in blacks. The authors evaluated 4,379 subjects from the Second National Health and Nutrition Examination Survey (1976-1980) for whom NIDDM was ascertained by medical history and oral glucose tolerance test, and for whom data on a number of risk factors were available. The prevalence of NIDDM was 60% higher in blacks than in whites (p < 0.001) and was highest in black women. Although most risk factors for NIDDM were more common in blacks, this higher frequency did not completely explain the racial disparity in the prevalence of NIDDM. After adjustment for all risk factors by logistic regression, an elevated risk of NIDDM was particularly evident at higher obesity levels in blacks as compared with whites; the odds were 70% higher for blacks at a percentage of desirable weight of 150 (95% confidence interval 1.1-2.8). The risk of NIDDM associated with obesity was greatest in black women: The odds in this group were sevenfold higher at a percentage of desirable weight of 150 versus 100 (95% confidence interval 2.6-18.8). The possibility of racial differences in metabolic adaptation to obesity highlights the importance of preventing this condition in blacks, particularly in black women.

Adult↗
PubMed1993

Sixteenth annual AAEM Edward H. Lambert Lecture. Electrodiagnostic aspects of diabetic neuropathies: entrapments. American Association of Electrodiagnostic Medicine.

A MEDLINE review suggested a lack of recent studies about the entrapments seen with underlying diabetic neuropathy. Suggested protocols for research in diabetic peripheral neuropathy have not included the concepts of entrapments as an early--indeed, first manifestation of the neuropathy. Carpal tunnel syndrome is a frequent accompaniment of diabetic peripheral neuropathy. Assessment of the degree of entrapment superimposed on the generalized peripheral neuropathy can be clarified by analysis of the CMAP and the SNAP--particularly with respect to duration of the negative spike of the action potential. Also, analysis of the action potentials elicited by stimulation of the ulnar and radial nerves and their comparison with the median nerve is often helpful. Finally careful inspection of the action potential when stimulating proximal and distal to the entrapment will establish the degree of nerve compromise relative to the underlying diabetic neuropathy.

Action Potentials↗
PubMed1993

Amplitude of M responses. Side to side comparability.

The peak amplitude of the M response from the extensor digitorum longus muscle (EDL) was measured in 26 healthy subjects (12 women and 14 men, aged 19 to 45 years) using conventional peroneal nerve stimulation at the fibular head. The mean amplitude of the EDL was 6.5 mV (+/- 1.3 mV) and 6.1 mV (+/- 1.2 mV) for the right and left sides, respectively. The side to side difference in amplitude of the M response was 0.4 mV (+/- 1.1 mV). Twenty-five of the twenty-six subjects had side to side amplitude differences within two standard deviations of the mean. None of the subjects had an EDL amplitude from the right lower limb over 1.8 mV less than that of the left, nor an EDL amplitude from the left lower limb over 2.8 mV less than that of the right. The technique used in the present study allows an accurate assessment of the M response amplitude from the EDL muscle. These reference data should prove useful in the evaluation of early focal nerve root injury (e.g. after 4 days, within 3 weeks) and in establishing prognosis for recovery in such conditions.

Action Potentials↗
PubMed1993

An immuno-electron microscopic comparison of olfactory marker protein localization in the supranuclear regions of the rat olfactory epithelium and vomeronasal organ neuroepithelium.

Immuno-electron microscopy was used to examine olfactory marker protein (OMP) ultrastructural localization in the supranuclear regions of the rat olfactory epithelium (OE) and vomeronasal organ (VNO) neuroepithelium. In the OE, OMP immuno-reaction product was observed within the cytoplasm of olfactory chemoreceptor cell dendrites, vesicles and cilia. Reaction product was absent from olfactory microvillar cells and their unique microvillar projections. In the neuroepithelium of the VNO, immuno-reaction product was seen within the dendrites of the chemoreceptor cells, and in the bases of their attached microvilli; the remaining distal portions of these microvilli were unlabeled. These results demonstrate a difference in the distribution of OMP immunoreactivity over the surfaces of the rat OE and VNO. They also show that OMP immunoreactivity does not exist in the rat olfactory microvillar cells.

Animals↗
PubMed1993

Hearing aids and otosclerosis.

The purpose of this article on the use of hearing aids in patients with otosclerosis is to emphasize that all otosclerosis patients cannot be assumed to be good users of hearing aid amplification. Patients with losses of 60 dB or less and with purely conductive lesions may be able to use aids well. Individuals with mixed-type impairments due to otosclerosis may have significant problems utilizing amplification. These cases demonstrate the use of hearing aid amplification in patients with mixed-type hearing impairment due to otosclerosis. This is a very different group of patients from the group with a pure conductive lesion, in which there is little problem in fitting a hearing aid, provided that the instrument has sufficient power and gain to override the loss. A special subgroup of patients who have far-advanced otosclerosis and have successful stapes surgery to correct the conductive component of their hearing loss present a unique problem. They may initially suffer from severe recruitment requiring patience, special training and compression-type hearing aids.

Aged↗
PubMed1992

Calbindin-like immunoreactivity in two peripheral chemosensory tissues of the rat: taste buds and the vomeronasal organ.

In the rat, calbindin-like immunoreactivity was observed at both the light and electron microscopic levels within the chemoreceptor neurons of the vomeronasal organ (VNO) and both intragemmal cells and associated nerve fibers of the circumvallate taste buds. All VNO neurons were immunoreactive. Only a subset of intragemmal taste cells was immunoreactive; associated immunoreactive nerve fibers were apposed to both labeled and unlabeled cells but no synaptic contacts were observed.

Animals↗
PubMed1992

Expression and function of insulin-like growth factor receptors on anti-CD3-activated human T lymphocytes.

The pattern of expression of receptors for insulin-like growth factors (IGF-I and IGF-II) and insulin was studied on monocyte-depleted human peripheral blood T cells activated via anti-CD3. Binding assays demonstrated the sequential appearance of receptors for IGF-I, IGF-II, and insulin on activated T cells. IGF-IR appeared early, their expression reaching maximum levels at or before the peak of cellular proliferation. IGF-IIR expression generally followed that of the IGF-IR and was more transient, with increases and decreases in expression paralleling the rise and decline of cellular proliferation. Insulin receptor expression remained low throughout the activation time course. The identity of the IGFR on anti-CD3-activated T cells was confirmed in affinity cross-linking experiments. These data demonstrated a 135,000 Mr peptide that specifically binds radiolabeled IGF-I and corresponds to the alpha subunit of the type I IGF-IR, and a 260,000 Mr peptide that specifically binds radiolabeled IGF-II and corresponds to the type II IGFR. We have additionally found that IGF-I and IGF-II (in nanomolar concentrations) produce as much as a threefold enhancement of T cell proliferation early in the activation process, correlating with the early appearance of IGF-IR. The effect of both IGF appeared to be mediated through the type I receptor, since an antibody (alpha IR3), which blocks binding to the alpha subunit of this receptor, inhibited enhancement by up to 83%. Furthermore, we have found expression of IGF-IR on T cells after activation to be associated with both CD4+ and CD8+ T cell subpopulations. These observations provide a foundation for investigating the contribution of IGF in regulating T cell proliferation, differentiation, and effector function.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1992

SPECT imaging of the benzodiazepine receptor: autoradiographic comparison of receptor density and radioligand distribution.

SPECT imaging of benzodiazepine (BZ) receptor using the antagonist [123I]iomazenil in nonhuman primates was correlated with ex vivo autoradiography and in vitro receptor autoradiography of postmortem tissue sections taken at the time of maximal brain uptake of the radiotracer. Cryostat sections prepared from brain tissue blocks at the orientation of the SPECT imaging plane showed high activity in gray matter regions, with gray to white matter ratios of greater than 30:1. After at least one week decay of 123I, these same tissue sections were used to localize and quantify the distribution of BZ receptors with the standard technique of in vitro receptor autoradiography using [125I]iomazenil. The ex vivo autoradiographic distribution of activity was highly correlated (r = 0.89) with the distribution of BZ receptors, although a few brain regions showed reproducible discrepancies between ex vivo and in vitro results. The ex vivo autoradiograms provided quantitative data from a realistic "biological phantom," which may be used to assess the accuracy of image reconstruction and to investigate differences between the distribution of an intravenously (i.v.) administered tracer and that of its target in brain tissue.

Animals↗
PubMed1992

Serial cultivation of normal human keratinocytes: a defined system for studying the regulation of growth and differentiation.

We have developed a defined method for human epidermal keratinocyte culture. The minimally supplemented basal medium supported establishment of primary cultures from neonatal foreskin in a defined environment. It also supported serial cultivation and rapid expansion of cell number. Casein replaced serum for defined cryopreservation. Cells were serially cultivated in medium containing 0.08 mM calcium. The rate of cell division however remained high after addition of 1.8 mM calcium. The particulate transglutaminase activity of the cultures was low at confluence, even in the presence of 1.88 mM calcium, indicating an enrichment of the basal cell population. Culture with small amounts (0.3%) of chelated serum increased particulate transglutaminase activity approximately 2.2-fold in low calcium cultures and approximately 3.5-fold in high calcium cultures. A gradual reduction in growth rate of serum-treated cultures upon serial cultivation also indicated a depletion of cells with basal cell character. Bovine hypothalamic extract and cholera toxin were able to avert, in part, the differentiation-promoting effects of serum. Keratinocytes serially cultivated in the defined medium maintained the ability to develop normally into a morphologically differentiated epidermis.

Blood Proteins↗