Showing papers by "Southern Illinois University School of Medicine published in 1993"

Optimized survival of hippocampal neurons in B27-supplemented Neurobasal, a new serum-free medium combination

Abstract: We have systematically optimized the concentrations of 20 components of a previously published serum-free medium (Brewer and Cotman, Brain Res 494: 65-74, 1989) for survival of rat embryonic hippocampal neurons after 4 days in culture. This serum-free medium supplement, B27, produced neuron survival above 60%, independent of plating density above 160 plated cells/mm2. For isolated cells (< 100 cells/mm2), survival at 4 days was still above 45%, but could be rescued to the 60% level at 40 cells/mm2 by simply applying a coverslip on top of the cells. This suggests a need for additional trophic factors. High survival was achieved with osmolarity lower than found in Dulbecco's Modified Eagle's Medium (DMEM), and by reducing cysteine and glutamine concentrations and by the elimination of toxic ferrous sulphate found in DME/F12. Neurobasal is a new medium that incorporates these modifications to DMEM. In B27/Neurobasal, glial growth is reduced to less than 0.5% of the nearly pure neuronal population, as judged by immunocytochemistry for glial fibrillary acidic protein and neuron-specific enolase. Excellent long-term viability is achieved after 4 weeks in culture with greater than 90% viability for cells plated at 640/mm2 and greater than 50% viability for cells plated at 160/mm2. Since the medium also supports the growth of neurons from embryonic rat striatum, substantia nigra, septum, and cortex, and neonatal dentate gyrus and cerebellum (Brewer, in preparation), support for other neuron types is likely. B27/Neurobasal should be useful for in vitro studies of neuronal toxicology, pharmacology, electrophysiology, gene expression, development, and effects of growth factors and hormones.

An overview of the uses of standardized patients for teaching and evaluating clinical skills. AAMC.

Abstract: The author defines the term standardized patient (SP), the umbrella term for both a simulated patient (a well person trained to simulate a patient's illness in a standardized way) and an actual patient (who is trained to present his or her own illness in a standardized way). He first discusses the many values of simulated patients over actual patients as teaching and assessment tools in the classroom and refutes a few myths about the use of SPs. Then he recounts the origin and development of SPs over a three-decade period, beginning with his work as a neurologist at the Los Angeles County Hospital, where he trained a model from the art department to simulate a neurological patient and assist in the assessment of clinical clerks. He then describes additional roles of SPs that have developed, including: (1) their use in the Clinical Practice Examination created at Southern Illinois University School of Medicine and (2) the major use that has come into being over the last 10-15 years; facilitating the comprehensive assessment of clinical competence using multiple stations in examinations such as the objective structured clinical examination. He concludes with information about recent and current work on SPs, who are becoming more and more accepted in the assessment process, and urges skeptics not to make judgments about the value of SPs until they have experienced the technique firsthand and reviewed the literature concerning the extensive and often high-quality research about this assessment tool.

Morphologic Analysis of the Microcirculation During Reperfusion of Ischemic Skeletal Muscle and the Effect of Hyperbaric Oxygen

Abstract: The morphologic events in the microcirculation that lead to reperfusion injury of ischemic skeletal muscle remain incompletely understood. The purpose of this experiment was to evaluate leukocyte endothelial adherence characteristics and dynamic changes in microvessel caliber during reperfusion of an in vivo skeletal muscle ischemia preparation. In addition, the effect of hyperbaric oxygen treatment on these microcirculatory changes also was studied. An intravital microscopy preparation of a transilluminated gracilis muscle in 27 rats was used to observe a total of 101 arterioles and 63 venules (13 to 73 microns diameter). Baseline hemodynamics were videotaped for 30 minutes following muscle isolation. The animals were divided into six groups: (1) sham, no ischemia, (2) 4 hours of global ischemia only, (3) no ischemia plus hyperbaric oxygen (one 2.5 ATA/1 hour of treatment with 100% oxygen), (4) 4 hours of ischemia plus hyperbaric oxygen during ischemia, (5) 4 hours of ischemia plus hyperbaric oxygen immediately on reperfusion, and (6) 4 hours of ischemia plus hyperbaric oxygen 1 hour after reperfusion. Changes in arteriolar and venular diameters at specific times during 3 hours of reperfusion were recorded, and the number of adherent and slow-rolling leukocytes in 100-microns venular segments were counted and compared with baseline measurements. The proximity of arterioles to venules was classified as adjacent ( 15 microns). No significant changes in leukocyte endothelial adherence or arteriolar diameter were noted in group 1 sham or group 3 nonischemic hyperbaric oxygen-treated rats when compared with baseline measurements. A significant increase in adherent leukocytes was observed in group 2 ischemic venules (+14.9 +/- 2.5) within 5 minutes of reperfusion, which was maintained for 3 hours. Reperfusion measurements of arteriolar diameter in group 2 ischemic muscle preparations demonstrated an initial vasodilation that was followed at 1 hour by a progressive and severe vasoconstriction (-46.9 +/- 11.3 percent at 3 hours) in arterioles adjacent to venules that was not seen in distant arterioles. The increase in adherent leukocytes seen in group 2 ischemic venules was significantly reduced by hyperbaric oxygen treatment given during ischemia (group 4) or up to 1 hour during reperfusion (groups 5 and 6). In addition, the progressive ischemic arteriolar vasoconstriction was inhibited in all groups (4, 5, and 6) treated with hyperbaric oxygen.(ABSTRACT TRUNCATED AT 400 WORDS)

Causes of urinary incontinence after acute hemispheric stroke.

Abstract: We prospectively studied bladder function in stroke patients to determine the mechanisms responsible for poststroke urinary incontinence.Fifty-one patients with recent unilateral ischemic hemispher...

Premature ageing in transgenic mice expressing different growth hormone genes.

Abstract: Transgenic mice expressing various growth hormone genes have markedly reduced life spans, with few animals surviving beyond 12 months in some of the lines. Except for an increased incidence of mammary tumours in female mice expressing human growth hormones, pathological findings in debilitated or moribund transgenic mice resemble the well-documented degenerative changes that occur at a much greater chronological age in normal rodents. This study demonstrates that 10-month-old male transgenic mice expressing bovine growth hormone (known as 25-copy PEPCK. bGH transgenic mice) also show age-related changes in hypothalamic and striatal neurotransmitter metabolism that are not seen in normal litter mate controls until at least 24 months of age. Female mice and male mice with a lower circulating concentration of bGH (known as 5-copy PEPCK. bGH transgenic mice) live longer and fail to show the same magnitude of change in neurotransmitter synthesis and release. Although more work needs to be done to determine the physiological significance of these changes and to determine their relationship to the general effects of ageing on the CNS, transgenic mice expressing various growth hormone genes may provide an interesting and valuable model with which to study the ageing process.

Induction of endogenous insulin-like growth factor-I secretion alters the hypothalamic-pituitary-testicular function in growth hormone-deficient adult dwarf mice.

Abstract: To evaluate the influence of growth hormone (GH) on hypothalamic-pituitary-testicular function, GH-deficient adult male Ames dwarf mice were treated (s.c.) twice daily for 8 days with either vehicle or bovine GH (25 tlg/injection/mouse). Normal male siblings treated with vehicle served as controls. Two in vivo experiments were conducted. In experiment 1, on Day 8, mice were treated (i.p.) with either saline or LHRH (1 ng/g b.w.) in saline. Fifteen minutes later, blood was obtained via heart puncture to assess plasma insulin-like growth factor-I (IGF-I), LH, and testosterone (T) levels by RIAs. In experiment 2, on Day 7, mice were bilaterally castrated and received injections of either oil or T propionate (1 utg/g b.w.) in oil. Eighteen to twenty hours later, blood was obtained as in experiment 1, and plasma IGF-I and LH levels were determined. In addition to these in vivo experiments, testicular androstenedione and T responses to hCG stimulation in vitro were evaluated. Administration of GH to dwarf mice increased (p < 0.001) plasma IGF-I levels, whereas IGF-I was not detectable in control dwarf mice. Plasma IGFI concentrations were higher in normal mice than in treated dwarf mice. Basal LH levels were lower (p < 0.025) in dwarf mice than those in normal mice. In dwarf mice, GH treatment increased (p < 0.001) plasma LH levels. The effect of LHRH on LH secretion was increased (p < 0.001) in dwarf mice pretreated with GH, but this LH response was lower than in normal siblings that received vehicle only. The castration-induced increase in plasma LH levels was attenuated (p < 0.05) in GH-deficient mice. However, GH treatment to these mice resulted in an increase (p < 0.001) in plasma LH levels. The suppressive effect of T propionate was attenuated (p < 0.001) in dwarf mice previously treated with GH. Although basal plasma T levels were similar in both normal and dwarf mice, plasma T response to the increase in plasma LH levels by LHRH treatment was decreased (p < 0.001) in vehicle-treated dwarf mice. Plasma T levels were similar in dwarf mice treated with GH and in vehicle-treated normal mice. Pretreatment of dwarf mice with GH resulted in increased production of androstenedione and T by the isolated testis treated with hCG. However, this response was higher (p < 0.001) in incubations containing testis obtained from normal mice. These results indicate that the hypothalamic-pituitary-testicular function is impaired in dwarf mice with hereditary GH deficiency and that induction of IGF-I secretion by GH treatment partially corrects these abnormalities. Therefore, it is conceivable that the derangement of neuroendocrine-testicular function in GH-deficient mice is due to lack of IGF-I secretion. Since these dwarf mice are also prolactin-deficient and exhibit hypothyroid symptoms, it is possible that GH, prolactin, and thyroid hormones may be required to establish normal hypothalamic, pituitary, and testicular functions in adult Ames dwarf mice.

Technical issues: test application. AAMC.

Abstract: Eighteen questions are posed that the authors believe address the major technical issues involved in the application of standardized patients (SPs). Following each question, selected empirical evidence and commentary are provided in response to the question and as background for further consideratio

Regulated expression of testis angiotensin-converting enzyme during spermatogenesis in mice.

Abstract: A unique isozyme of angiotensin-converting enzyme (ACE) is produced in large amounts by developing germ cells and is referred to as testis ACE. This protein results from the transcriptional recognition of a sperm-specific promoter during spermatogenesis. The expression within germ cells of testis ACE mRNA was studied using in situ hybridization, ribonuclease (RNase) protection, and Northern analysis. In parallel, testis ACE protein expression was measured through use of Western blot analysis and immunohistochemistry. Although testis ACE protein is first detected in step 10 spermatids, testis ACE mRNA is first detected in a developmentally younger cell population, late pachytene spermatocytes. Thus, testis ACE mRNA is translationally arrested for a period of several days until late in spermiogenesis.

Recombinant Human Follicle-Stimulating Hormone Is Capable of Exerting a Biological Effect in the Adult Hypophysectomized Rat by Reducing the Numbers of Degenerating Germ Cells*

Abstract: There is considerable controversy as to whether FSH can, under normal circumstances, exert an effect to promote spermatogenesis in the adult rat. Recombinant human FSH (rhFSH) was used to answer a more limited question relating to whether FSH is capable of exerting a biological effect in promoting adult spermatogenesis. Can a pure preparation of FSH prevent the regressive changes seen after hypophysectomy (Hx) in a short term experiment? To answer this question, five groups of adult rats were used as follows: pituitary-intact animals, 3-day hypophysectomized (Hx), 3-day Hx given 3 mg testosterone propionate (T)/day for 7 days, 3-day Hx given 22 IU rhFSH for 7 days, and 3-day Hx given saline vehicle for 7 days. Testis weight, seminiferous tubule diameter, analysis of four degenerating germ cell types, the relative amount of lipid, and the levels of FSH receptors showed that FSH could, in a significant manner, prevent the regressive changes accompanying Hx. FSH was not as effective as T in doing so, because...

Diuretic and diet effect on Menière's disease Evaluated by the 1985 Committee on Hearing and Equilibrium Guidelines:

Abstract: Fifty-four patients, diagnosed with Meniere's disease and treated with diuretics and a low-salt diet, were evaluated retrospectively with the 1985 AAO/HNS Committee on Hearing and Equilibrium (CHE) guidelines for vertigo and hearing changes. The patient data base was also evaluated with other methods that helped determine the effectiveness of the 1985 AAO/HNS CHE guidelines. After 24 months of therapy, vertigo control was complete or substantial in 79% of the patients, limited or insignificant in 19%, and worse in 2% as evaluated by the CHE 1985 guidelines. Hearing improved in 35% of the patients, was unchanged in 29%, was worse in 22%, and could not be classified by CHE guidelines in 14%. Hearing was also evaluated by comparison of individual thresholds before medical therapy, and at 22 and 74 months after the start of medical therapy. We found a stabilization of low- and mid-threshold frequencies, with an average rate of hearing loss approximating 0 dB/yr with 74 months of followup. The results of this preliminary study suggest that diuretics and a low-salt diet may decrease the natural progression of sensorineural hearing loss in patients with Meniere's disease. Compared with other methods of data analysis, the 1985 CHE guidelines lacked sensitivity to evaluate the hearing changes observed.

Pathologic changes associated with intracranial hypotension and meningeal enhancement On MRI

Abstract: We report a patient with a 6-week history of postural headache due to intracranial hypotension whose MRI revealed findings typical of this syndrome, including diffuse meningeal enhancement following gadolinium infusion. Biopsy revealed extensive fibrocollagenous proliferation in the leptomeninges without evidence of inflammation. The pathologic changes in this patient, which occurred soon after the onset of symptoms, are probably related to the striking meningeal enhancement seen in this syndrome.

Surface and surface-to-volume relationships of the Sertoli cell during the cycle of the seminiferous epithelium in the rat

Abstract: The surface relationships of the Sertoli cell and the surface relationships of the Sertoli cell in comparison to the changing volumes of developing germ cells were studied using morphometric techniques at periods representing nine groupings of the fourteen defined periods in the cycle of the seminiferous epithelium of the adult rat. No cyclic variation in the total Sertoli plasma membrane surface area was noted. Cyclic variations were noted in the area of the Sertoli cell surface that faces the basal compartment germ cells, but not the basal lamina. No cyclic variations were noted in the amount of contact of the Sertoli cells with each other at the level of the Sertoli cell barrier. However, when areas in the adluminal compartment were studied, significantly less Sertoli-Sertoli contact was seen in stages V through VII than in other stages with the exception of stages II-IV. Surface contact of germ cells with Sertoli cells increased progressively as germ cells entered the intermediate compartment and progressed to late spermatids. However, a calculation of the surface-to-volume ratio showed that surface increases of the Sertoli cell in relation to the volume of germ cells were greatest in elongating spermatids past step 12 of spermiogenesis. The area in which Sertoli ectoplasmic specializations faced germ cells was determined throughout spermatogenesis, and these data demonstrated that the first appearance of ectoplasmic specialization was at the mid-pachytene phase. They also showed that stage VIII was a period when ectoplasmic specialization loss from the cell surface was evident. Less Sertoli ectoplasmic specialization face step 8 and step 19 spermatids than comparable germ cell types at other stages. In addition to Sertoli cell surface area changes during the cycle, volumes of individual germ cell types were determined for the first time. The data presented allow an objective understanding of the complex structure and relationships of the Sertoli cell and provide a basis for understanding functional changes and interpreting biochemical data.

Nicotinic agonists modulate basal forebrain control of cortical cerebral blood flow in anesthetized rats.

Abstract: Previous studies have indicated that electrical microstimulation of the cholinergic (basal forebrain, BF) elicits profound increases in cortical cerebral blood flow (CBF) that are selectively attenuated by nicotinic receptor antagonists. This study sought to determine whether nicotinic receptor agonists such as (-)-nicotine, and related agents, can enhance the increases in CBF elicited by electrical stimulation of the BF of urethane-anesthetized rats. The magnitude of cortical CBF responses, measured by laser-Doppler flowmetry, increased progressively with higher frequencies (range = 6.25-50 Hz) to a maximum of 248% of control. (-)-Nicotine and (-)-lobeline each further enhanced the responses to BF stimulation, with (-)-nicotine having the most potent effect (up to 350%). (+)-Nicotine and (-)-cotinine were without effect, suggesting stereoselectivity and that the effects were not mediated by the major metabolite of (-)-nicotine. In contrast, (-)-cystisine, another nicotinic receptor agonist, modestly inhibited the BF-elicited increase in CBF suggesting nicotinic receptor subtype selectivity in mediating the response. Arecoline, a potent muscarinic agonist, was without effect suggesting that muscarinic mechanisms are not involved in the mediation of this response. None of the nicotinic agents had overt effects on heart rate or blood pressure in the dose ranges examined. In experiments targeting the site of action of the nicotinically mediated enhancement, (-)-nicotine microinjections into the BF elicited profound increases in cortical CBF, whereas similar injections into the cerebral cortex were without effect suggesting that nicotine receptors mediating CBF increases are localized to the BF.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Examinee Gender, Standardized-Patient Gender, and Their Interaction on Standardized Patients' Ratings of Examinees' Interpersonal and Communication Skills.

Abstract: PURPOSE. To assess the effects of examinee gender, standardized-patient (SP) gender, and, in particular, their interaction on ratings made by SPs of examinees' interpersonal and communication skills in a performance-based examination of clinical competence. METHOD. The examination was administered t

Role of nitric oxide in neurogenic vasodilation of porcine cerebral artery.

Abstract: A superfusion bioassay cascade, with porcine pial arteries as donor tissues and rabbit aortic rings as detector tissues, was used to examine the role of nitric oxide (NO) in cerebral nonadrenergic, noncholinergic neurogenic vasodilation. All arteries were mechanically denuded of endothelium. In the presence of atropine (1 microM) and guanethedine (0.3 microM), transmural nerve stimulation (TNS) of cerebral arteries (CA) resulted in a frequency-dependent relaxation of phenylephrine-precontracted aortic rings. Relaxation was abolished by tetrodotoxin (2 microM) superfused onto and by cold-storage denervation of CA, suggesting that a vasodilating factor (VF) of neuronal origin in CA was released upon TNS. The VF-induced relaxation was inhibited by NW-nitro-L-arginine (0.3 mM) superfused onto CA. This inhibition was reversed by L-arginine (0.3 mM) but not D-arginine (0.3 mM). Exogenously applied NO onto CA also induced dilations of aortic rings in a concentration-dependent manner. The VF- and NO-induced dilations, which were abolished by hemoglobin (0.3 microM), and enhanced by superoxide dismutase (30 U/ml), declined to the same extent with similar time courses from the first to the second aortic ring. These findings indicate that VF and NO possess a similar labile nature and half-life, suggesting that VF is NO or a related substance. Identical frequency-response curves of TNS (2-16 Hz) and concentration-response curves of NO (10-1000 nM) further suggest that < 1000 nM of NO was released from CA upon TNS at the maximal frequency used.(ABSTRACT TRUNCATED AT 250 WORDS)