Showing papers by "Southern Illinois University School of Medicine published in 1990"
TL;DR: Significant, selective, age-related loss of the putative inhibitory neurotransmitter GABA in the central nucleus of the inferior colliculus of rat based on immunocytochemical and neurochemical data support the hypothesis that impairment of inhibitory GABAergic neurotransmission in the CIC may contribute to abnormal auditory perception and processing seen in neural presbycusis.
Abstract: The present study describes substantial, selective, age-related loss of the putative inhibitory neurotransmitter GABA in the central nucleus of the inferior colliculus (CIC) of rat based on immunocytochemical and neurochemical data. For immunocytochemistry, neurons in the CIC were immunolabeled using an antibody against a GABA conjugate in young adult (2- to 7-month-old) and aged (18- to 29-month-old) Fischer-344 rats. Computer-assisted morphometry was then used to generate maps of GABA- immunoreactive neurons in the CIC. The number of GABA-positive neurons was reduced 36% in the ventrolateral portion of the CIC of aged animals (93 neurons/mm2) compared to their matched young adult cohorts (145 neurons/mm2; p less than 0.01). For neurochemistry, basal and K(+)- evoked release of the endogenous amino acids GABA, glutamate (Glu), aspartate (Asp), and tyrosine (Tyr) from micropunches of the CIC were measured in 8 age-paired animals from the 2 age groups using high- performance liquid chromatography. Overflow of radiolabeled acetylcholine (3H-ACh) was also determined. In both age groups, K(+)- evoked release of GABA, Glu, Asp, and 3H-ACh from CIC punches was significantly enhanced above basal efflux (+200, +215, +163, and +309%, respectively), while Tyr release was unchanged. Evoked release of 3H- ACh and all amino acids except Tyr showed substantial Ca2+ dependence. A significant (p less than 0.05) age-related reduction in both basal (- 35%) and K(+)-stimulated (-42%) efflux of GABA from the CIC was observed. A corresponding decrease in postrelease tissue content of GABA in CIC of aged rats was observed (-30%, p less than 0.05). In contrast, tissue content as well as basal and evoked release of Glu, Asp, Tyr, and 3H-ACh was similar between the 2 age groups. Age-related GABA neurochemical changes described in the CIC were not observed in the release of the other amino acids or 3H-ACh from either the rostral ventrolateral medulla or the somatosensory cortex, 2 brain regions involved in processing non-auditory sensory input. These data support previous findings that GABA, Glu, Asp, and ACh may subserve neurotransmission in the CIC. Additionally, these data provide clear evidence for a pronounced, region- and neurotransmitter-selective, age- related reduction of GABA in the CIC. These findings support the hypothesis that impairment of inhibitory GABAergic neurotransmission in the CIC may contribute to abnormal auditory perception and processing seen in neural presbycusis.
226 citations
TL;DR: Recognition of the influence of complications on charges suggests that low average charges can only be achieved by surgical programs with a low complication rate.
Abstract: This is a prospective study of 500 consecutive patients having coronary artery bypass surgery; mean hospital charge from time of surgery to discharge was $11,900 ± 12,700. Multiple regression analysis was performed using preoperative variables and postoperative complications. No preoperative clinical feature was a significant predictor of higher average charge. Sternal wound infection (p = 0.0001), respiratory failure (p = 0.0001) and left ventricular failure (p = 0.017) were associated with higher average hospital charge. The absence of any complication predicted a lower average charge, and postoperative death (4.4 ± 4.5 days after surgery) was also associated with lower average charge. A cost equation was developed: hospital charge equalled $11,217 + $41,559 for sternal wound infection, + $28,756 for respiratory failure, + $5,186 for left ventricular failure, − $1,798 for no complication and − $6,019 for death. Recognition of the influence of complications on charges suggests that low average charges can only be achieved by surgical programs with a low complication rate.
196 citations
TL;DR: Alzheimer's disease does not affect all subtypes of nicotinic receptors in the frontal cortex to the same extent, and it is concluded that 125I‐κ‐bungarotoxin sites are not significantly different in number from age‐matched control brains.
Abstract: Molecular genetic and pharmacological studies have suggested that several subtypes of nicotinic acetylcholine receptors exist in the mammalian and avian brain. Combining 3H-(-)-nicotine, 125I-alpha-bungarotoxin, and 125I-kappa-bungarotoxin as ligands, we report here the first evidence for the existence in human frontal cortex of at least three different subtypes of nicotinic receptors. Autoradiographic analysis shows that specific 125I-kappa-bungarotoxin binding sites are concentrated mainly in several cortical layers. We also show that kappa-bungarotoxin, but not alpha-bungarotoxin decreases the evoked release of 3H-acetylcholine in rat cortical slices, indicating a likely presynaptic localization for some of the alpha-bungarotoxin-insensitive kappa-bungarotoxin sites in mammalian brain. The brains of patients with Alzheimer's disease show marked decreases in Bmax values for low-affinity 125I-kappa-bungarotoxin sites and both high- and low-affinity 3H-nicotine sites, whereas 125I-alpha-bungarotoxin sites are not significantly different in number from age-matched control brains. We conclude that Alzheimer's disease does not affect all subtypes of nicotinic receptors in the frontal cortex to the same extent.
148 citations
TL;DR: Existence of paralysis agitans prior to the industrial revolution is not just of historical interest, but would also suggest that under the hypothesis of exposure to environmental toxins as a possible cause of paralysis Agitans, natural organic compounds with worldwide distribution should also be considered.
Abstract: Neurologic diseases (Vata rogas, Sanskrit) and the pharmacologic treatment of them were described in the ancient Indian medical system--Ayurveda. This article explores paralysis agitans, which was described under the name Kampavata. Mucuna pruriens (Atmagupta, Sanskrit), which contains levodopa, was used in the treatment of Kampavata. Existence of paralysis agitans prior to the industrial revolution is not just of historical interest, but would also suggest that under the hypothesis of exposure to environmental toxins as a possible cause of paralysis agitans, natural organic compounds with worldwide distribution should also be considered.
116 citations
TL;DR: The realities of long-term care call for a refurbished, concrete concept of autonomy that systematically attends to the history and development of persons and takes account of the experiences of daily living.
Abstract: The realities of long-term care call for a refurbished, concrete concept of autonomy that systematically attends to the history and development of persons and takes account of the experiences of daily living.
108 citations
TL;DR: These studies document profound and characteristic differences between the normal aging and the pathological Alzheimer brain with regard to cholinergic receptor localization, distribution, and function.
Abstract: A general review of cholinergic receptors in human brain is presented. The paper focuses upon changes in normal aging brain and in Alzheimer disease. Studies from five different approaches are reported: 1) molecular biology; 2) receptor binding studies; 3) studies with specific neurotoxins; 4) immunocytochemistry; and 5) PET scan. These studies document profound and characteristic differences between the normal aging and the pathological Alzheimer brain with regard to cholinergic receptor localization, distribution, and function.
104 citations
TL;DR: A statistically significant improvement in the Alzheimer Disease Assessment Scale (ADAS) scores was observed with the 5 mg/kg/wk dose of metrifonate, and over 80% inhibition of plasma and RBC ChE was achieved with only minor side effects.
Abstract: This is the first study of a multiple-dose trial of metrifonate (Met), a long-acting cholinesterase (ChE) inhibitor, conducted over a prolonged period of time in humans. We have administered Met to 20 patients who met NINCDS-ADRDA criteria for probable Alzheimer disease (AD). Patients were given, under open conditions, single oral doses of Met. 2.5, 5, 7.5, and 15 mg/kg/wk. A statistically significant improvement in the Alzheimer Disease Assessment Scale (ADAS) scores was observed with the 5 mg/kg/wk dose. Maximal improvement on the ADAS was associated with a mean 55.9% (± 12.6% standard deviation) activity level of red blood cell (RBC) acetylcholinesterase (AChE). Over 80% inhibition of plasma and RBC ChE was achieved with only minor side effects. Cholinesterate inhibition in the CSF of two patients was 37% and 47.5% 24 hr after a second dose of 5 mg/kg/wk of Met separated by 7 days from the first dose.
Twenty-seven minor side effects were reported: none on 2.5 mg, 5 on 5 mg, 9 on 7.5 mg, and 13 on the 15 mg dose. None of the side effects was clinically significant or drug related or required termination of treatment of dosage adjustment. We conclude that Met is a useful pharmacological probe of cholinergic function in the central nervous system and that double-blind evaluation of Met in AD is warranted.
95 citations
TL;DR: In this article, the effect of a series of antisense oligodeoxyribonucleotides [oligo(dN)] on the expression of the surface antigen (HBsAg) gene of human hepatitis B virus (HBV) was examined using hepatocellular carcinoma cells that contain integrated HBV genomes.
Abstract: The effect of a series of antisense oligodeoxyribonucleotides [oligo(dN)] on the expression of the surface antigen (HBsAg) gene of human hepatitis B virus (HBV) was examined using hepatocellular carcinoma cells that contain integrated HBV genomes. Of a number of antisense oligo(dN)s tested, synthetic 15-mers directed at the cap site of mRNA and regions of the translational initiation site of the HBsAg gene were found to be highly effective and inhibited viral gene expression by as much as 96%. The inhibition was specific to the HBsAg gene and appeared to be at the level of translation. These results suggest a therapeutic potential for antisense oligo(dN) in the treatment of patients who are chronically infected with HBV.
95 citations
TL;DR: A review of the literature on gangliosides and their roles in neuronal function, synaptic transmission, and the role of ganglioides in synaptic neurotransmission finds that the former is important for neuronal function and the latter for synaptic transmission.
91 citations
TL;DR: Choline acetyltransferase (ChAT), the synthetic enzyme for acetylcholine (ACh), is consistently reduced by 50%–95% in cortex and hippocampus of AD patients compared to age-matched controls.
Abstract: Publisher Summary This chapter describes the cholinergic system in Alzheimer disease (AD). Choline acetyltransferase (ChAT), the synthetic enzyme for acetylcholine (ACh), is consistently reduced by 50%–95% in cortex and hippocampus of AD patients compared to age-matched controls. Reductions are also observed in high-affinity choline uptake (HACU), in in vitro synthesis of ACh and release during depolarization, in presynaptic muscarinic and nicotinic receptor binding, in ACh and acetylcholinesterase (AChE) levels in cortex and in cerebrospinal fluid (CSF). The reduction of these presynaptic cholinergic markers is associated with a marked loss of cells in the nucleus basalis of Meynert, which project to cortex. The postsynaptic muscarinic receptor mechanisms appear to be relatively spared in AD patients. The reductions of cortical and CSF cholinergic markers are closely correlated with the extent of neuropathology and with the severity of cognitive impairment. The chapter also discusses the changes in ACh and Ch metabolism in aging animals and in the CSF of AD patients, which may be related to neuronal membrane breakdown and reduced uptake of Ch by cholinergic neurons.
90 citations
TL;DR: Handwriting and drawing are commonly employed in the clinical assessment of tremor by subjective rating schemes, but digitizing tablets lack sufficient sensitivity to measure physiologic tremor.
TL;DR: In a monkey performing a visual delayed matching-to-sample task, units and visual evoked potentials (VEPs) were sampled from the inferior bank of the superior temporal sulcus, the hippocampus, and the presubiculum, and VEP latencies indicated that flash information reached the hippocampus substantially earlier than the STS.
Abstract: In a monkey performing a visual delayed matching-to-sample task, units and visual evoked potentials (VEPs) were sampled from the inferior bank of the superior temporal sulcus (STS; Areas TEa and IPa), the hippocampus, and the presubiculum. VEP latencies indicated that flash information--signaling the imminent presentation of a color sample to be retained--reached the presubiculum and the hippocampus substantially earlier than the STS. In contrast, color sample VEP latencies did not differ between sites, arriving at all sites appreciably later than flash VEPs. Unit data indicated generally excitatory responses to both stimuli at all sites and net inhibition during the interstimulus interval separating flash from sample. As with VEPs, unit latencies to flash were shorter than to sample stimuli. The alerting flash data imply activation of the hippocampus occurring before activation of the STS cortex, whereas the coincident arrival of color sample information suggests temporal synchronization between these structures.
TL;DR: This result suggests that uptake of tracers in the vagina was not due to toxic effects, and that the vagina and cervix are major sites of protein uptake into the reproductive tract.
TL;DR: Five patients exhibited severe tremor in the upper extremity, primarily when attempting to write or draw, and muscles throughout the affected extremity exhibited rhythmic 5–7‐Hz bursts of motor unit discharge, and the average level ofotor unit activity was tonically increased in antagonistic muscles.
Abstract: Five patients exhibited severe tremor in the upper extremity, primarily when attempting to write or draw. Electromyography was performed to determine the patterns of muscle activity that were responsible for this tremor. Tremor was measured with an accelerometer and with a digitizing tablet. Two patients had postural tremor that was indistinguishable from mild, high-frequency essential tremor. All patients exhibited a severe 5-7-Hz tremor during the acts of writing and drawing. Muscles throughout the affected extremity exhibited rhythmic 5-7-Hz bursts of motor unit discharge, and the average level of motor unit activity was tonically increased in antagonistic muscles. This abnormal coactivation of antagonistic muscles produced subtle dystonic posturing of the affected limb that was overshadowed by severe tremor. Electromyography was useful in confirming the coexistence of tremor and dystonia in our patients. The nonspecificity of dystonia and postural tremor must be considered when discussing the nosology and pathophysiology of primary writing tremor.
TL;DR: Compared choline acetyltransferase activity (as a structural marker) and sodium‐dependent high affinity choline uptake (which reflects both ongoing cholinergic neuronal activity and structural integrity) in the hippocampus, cortex and striatum of male C57BL mice at 3–4, 10–12 or 28–32 months of age.
TL;DR: A procedure for performing full-thickness, penetrating keratoplasty in the mouse and a critical evaluation of the role of a variety of immunological mediators in causing graft failure is developed.
Abstract: In an attempt to overcome the lack of well characterized, inbred, and congenic strains, as well as a paucity of immunological reagents, in rabbit and rat models, we have developed a procedure for performing full-thickness, penetrating keratoplasty in the mouse. One hundred percent of isografts (BALB/c onto BALB/c) were successful, while 83.3% of allografts (C3H onto BALB/c) failed. The use of a mouse model to study corneal graft failure will allow a critical evaluation of the role of a variety of immunological mediators in causing graft failure.
TL;DR: Treatment of adult male rats with a low dose of THC suppresses LH secretion and that CBN and CBD potentiate this action of THC, suggesting alterations in hypothalamic noradrenergic activity may be involved in this effect.
Abstract: The acute effects of low oral doses of delta 9-tetrahydrocannabinol (THC), cannabinol (CBN) and cannabidiol (CBD) administered alone or in combinations on LH and prolactin (PRL) secretion and on hypothalamic norepinephrine (NE), dopamine (DA) and serotonin (5-HT) dynamics were examined in adult male rats. Plasma LH levels were significantly reduced 60 min after administration of 0.5 mg THC/kg body weight and 30, 60 and 120 min after administration of THC + CBN or THC + CBD. There were no changes in plasma PRL in response to cannabinoid treatments. The turnover of NE in both the median eminence (ME) and medial basal hypothalamus (MBH) was dramatically affected by all the cannabinoid treatments. Complete suppression of NE turnover occurred 30 min post-THC and 120 min post-THC + CBN in the ME and 120 min post-THC + CBD in the MBH. Cannabinoids did not significantly affect DA turnover in the MBH or the content of NE, DA, 5-HT or 5-hydroxyindole-3-acetic acid in either the ME or MBH. These data demonstrate that treatment of adult male rats with a low dose of THC suppresses LH secretion and that CBN and CBD potentiate this action of THC. Although the mechanisms responsible for the inhibition of LH release by cannabinoids cannot be positively identified from these experiments, the results suggest that alterations in hypothalamic noradrenergic activity may be involved in this effect.
TL;DR: The findings suggest that the threshold for triggering brain-stem seizure discharge by electroshock is lower than that for triggering forebrain seizure discharge inGEPR-9s, whereas the reverse relationship is true in normal rats and GEPR-3s.
TL;DR: Patients with chronic intractable pruritus ani are diagnosed and methylene blue (methylthionine chloride) 0.5 percent is injected intracutaneously on the anodermal and perianal skin and with one treatment, long-term cure has been observed.
Abstract: The majority of patients with idiopathic pruritus ani respond favorably to conservative treatment. Moreover, response to specific medical therapy is almost always favorable in certain dermatologic diseases such as psoriasis, mycotic dermatitis, and contact dermatitis. When surgery is performed for anorectal disorders such as hemorrhoids and fistulas, or potentially malignant entities such as extramammary Paget's disease, the accompanying pruritus ani invariably improves as well. Only patients with chronic intractable pruritus ani are included in the current study. Methylene blue (methylthionine chloride) 0.5 percent is injected intracutaneously on the anodermal and perianal skin. With one treatment, long-term cure has been observed.
TL;DR: It is suggested that factors present in the human fallopian tube may limit susceptibility to chlamydial infection but support the use of the HFTOC model in the study of the pathogenesis of C. trachomatis salpingitis.
Abstract: The pathogenic events that precede Chlamydia trachomatis salpingitis in the human fallopian tube have not been fully described. We used a model of human fallopian tubes in organ culture (HFTOC) infected with strain E/UW-5/CX of C. trachomatis to study these events. The model supported sustained C. trachomatis infection as demonstrated by recovery of viable C. trachomatis from medium and tissue over 5-7 d. However, the level of infectivity was low. Maximal infection occurred at 72 h after initial inoculation. In contrast to gonococcal infection of the HFTOC, C. trachomatis did not damage overall ciliary function of HFTOC. However, a local direct cytotoxic effect characterized by loss of microvilli and disruption of cell junctions was noted when multiple chlamydial elementary bodies attached to mucosal cells. Beginning at 24 h, and continuing throughout the course of C. trachomatis infection of HFTOC, ruptured epithelial cells releasing elementary bodies were noted. Chlamydial inclusions were seen in the mucosa by 72 h in approximately 6% of both ciliated and nonciliated epithelial cells. Mucosal inclusions contained all forms of the C. trachomatis developmental cycle. These data suggest that factors present in the human fallopian tube may limit susceptibility to chlamydial infection but support the use of the HFTOC model in the study of the pathogenesis of C. trachomatis salpingitis.
Journal Article•
TL;DR: Results of these studies indicate that IC injection of allogeneic lymphocytes results in prolonged acceptance of corneal grafts syngeneic with the injected lymphocytes.
Abstract: Failure of corneal grafts is thought to involve the development and activation of specifically sensitized T-cells. One method which might be used to circumvent the development of such cells is the phenomenon of anterior chamber-associated immune deviation (ACAID). Injection of antigen into the anterior chamber of the eye leads to an immune response characterized by normal antibody response coupled with depressed T-cell reactivity especially as measured by delayed-type hypersensitivity. To determine if this phenomenon could be used to alter the course of graft failure, potential recipients (Lewis rats) were injected intracamerally (IC) with allogeneic lymphoid cells (Wistar-Furth). Orthotopic, full-thickness, penetrating keratoplasty was done 0-30 days later, and the recipients were observed for at least 60 days. Approximately 75% of Wistar-Furth corneal grafts placed on uninjected Lewis rats failed as evidenced by continued opacity, edema, and infiltration of mononuclear cells into the grafts. The IC injection of Wistar-Furth lymphocytes decreased this failure rate to 25% and 50% when grafting was done 14 and 7 days after injection, respectively. Grafts of cornea from a third strain onto IC injected animals failed at an intermediate rate which demonstrated some immunologic protection. The results of these studies indicate that IC injection of allogeneic lymphocytes results in prolonged acceptance of corneal grafts syngeneic with the injected lymphocytes.
TL;DR: Despite its importance this skill of inquiry is not given appropriate emphasis in the education of medical students or in research concerning the clinical reasoning skills of doctors.
Abstract: The skill of inquiry is central to the task of the doctor confronted with a patient problem. Despite its importance this skill is not given appropriate emphasis in the education of medical students or in research concerning the clinical reasoning skills of doctors.
TL;DR: A substantial portion of tonic sympathetic activity may be driven by activation of muscarinic receptors in the C1 area of nucleus reticularis rostroventrolateralis in the rat.
TL;DR: Since 5-HT failed to oscillate in the absence of environmental time cues, the rhythm is likely driven by the environment and not an internal circadian clock.
TL;DR: It is concluded that severe disease of the contralateral carotid artery can lead to overreading ipsilateral disease and that velocity determinations should be interpreted cautiously under such circumstances.
TL;DR: It is demonstrated that many but not all of the adverse effects of STZ-D on copulatory behavior and neuroendocrine function can be reversed by insulin replacement.
Abstract: The ability of insulin replacement to reverse the adverse effects of streptozocin-induced diabetes (STZ-D) on neuroendocrine and sexual function was tested in adult male rats. Rats were injected with STZ (50 mg/kg) or vehicle and then either started immediately on insulin (continuous) or allowed to remain untreated for 4 wk before insulin replacement was started (delayed). Replacement consisted of 5 IU/kg of insulin injected just before the lights were turned off and 2 IU/kg of insulin injected within 1 h of the lights being turned on. Copulatory behavior was tested 2, 4, 5, and 6 wk after induction of diabetes. Forty-five days after STZ administration, rats were killed for measurement of plasma hormone levels and hypothalamic catecholamine turnover and serotonin content. The STZ-D rats showed significant deficits in mount, intromission, and ejaculatory behaviors that were prevented by continuous insulin replacement. Delayed insulin replacement reversed the deficits in mount and intromission behaviors but not ejaculatory behavior. Plasma luteinizing hormone levels were unaffected by STZ or insulin treatment, but plasma testosterone and prolactin levels were both reduced in the diabetic animals. Continuous or delayed insulin replacement normalized both testosterone and prolactin levels. Median eminence, medial basal hypothalamus, anterior hypothalamus, and olfactory bulb rates of norepinephrine turnover were all reduced after STZ administration. Delayed insulin replacement restored norepinephrine turnover in all brain regions, whereas continuous insulin replacement enhanced norepinephrine turnover in the anterior hypothalamus and olfactory bulb but only partially blocked the effects of STZ in the median eminence and medial basal hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Senectutis autem nullus est certus terminus, recteque in ea vivitur quoad munus offici exsequi… vivundi est finis optumus cum integra mente mente certisque sensibus opus ipsa suum eadem quae coagmentavit natura dissolvit.
Abstract: Senectutis autem nullus est certus terminus, recteque in ea vivitur quoad munus offici exsequi… vivundi est finis optumus cum integra mente certisque sensibus opus ipsa suum eadem quae coagmentavit natura dissolvit Cicero, “De Senectute”
Journal Article•
TL;DR: A case of a child with clinical and pathologic evidence of group Ill Mobius syndrome whose CT and MR studies showed a hypoplastic brainstem and calcification in the abducens nerve nuc:ei is reported.
Abstract: Mobius syndrome is a congenital neuromuscular disorder characterized by both inability to abduct the eyes and facial weakness [1] . It is classified into four groups on the basis of whether the primary abnormalities are diffuse (group 1), in the abducens and facial nerves (group II), or nuclei (group Ill), or lie outside the CNS (group IV) [2]. Although the radiologic findings of the musculoskeletal abnormalities associated with Mobius syndrome have been reported [3] , no prior imaging studies of the primary CNS abnormalities have been published. We report a case of a child with clinical and pathologic evidence of group Ill Mobius syndrome whose CT and MR studies showed a hypoplastic brainstem and calcification in the abducens nerve nuc:ei . Radiologic-pathologic correlation is presented .
TL;DR: Cause-specific, age-adjusted mortality rates have declined from 1950 through 1986 for cerebrovascular disease, injuries, perinatal conditions, heart disease, and influenza and pneumonia, while the proportions of persons dying of chronic obstructive pulmonary disease and malignant neoplasms have increased dramatically.
Abstract: Mortality trends in the United States from 1950 through 1986 were analyzed for the conditions that are or have recently been among the six leading causes of death. The age-adjusted mortality rate for all causes has decreased from 841.5 to 541.7 per 100 000 population. Cause-specific, age-adjusted mortality rates have declined from 1950 through 1986 for cerebrovascular disease, injuries, perinatal conditions, heart disease, and influenza and pneumonia. Time trends in the proportion of persons dying of each of these diseases, however, have varied; the proportion dying of cerebrovascular disease, injuries, and perinatal conditions has decreased, and the proportion of persons dying of heart disease and influenza and pneumonia has remained fairly stable from 1950 through 1986. During this same time, age-adjusted death rates have increased for chronic obstructive pulmonary disease and have remained fairly stable for malignant neoplasms, while the proportions of persons dying of chronic obstructive pulmonary disease and malignant neoplasms have increased dramatically. For people aged 35 to 64 years, malignant neoplasms have now overtaken heart disease as the leading cause of death. For those aged 65 years and older, heart disease remains the leading cause of death, accounting for almost 50% of all deaths in persons 85 years and older. (JAMA. 1990;264:3178-3184)
TL;DR: Auditory brain stem response (ABR) thresholds to clicks in the GEPR substrain that exhibits exclusively maximal AGS severity (GEPR-9) were significantly elevated, and latencies for ABR peaks I, III, and IV were significantly increased as compared to normal Sprague-Dawley rats, suggesting that an inverted U-shaped relationship exists between hearing deficit andAGS severity.