Diagnostic delay in appendicitis.
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Appendicitis↗
Biomedical subjects
D Wilson
Publications and source records attributed to D Wilson.
Proton MR spectroscopy in patients with neurofibromatosis type 1: evaluation of hamartomas and clinical correlation.
PURPOSE: To use proton MR spectroscopy in patients with neurofibromatosis type 1 to determine: (a) the spectroscopic characteristics of hamartomas and compare them with that of gliomas; (b) whether differences exist between patients with and without learning disabilities; and (c) spectroscopic patterns in normal-appearing brain (by MR imaging) in patients with and without focal lesions. METHODS: Seventeen proton MR spectroscopy volumes were obtained in 10 patients with neurofibromatosis type 1 (including hamartomas, N = 7; normal-appearing brain, N = 10). Seven patients had learning disorders, and 3 were mentally normal. Ten healthy volunteers and 10 patients with pathologically proved gliomas (all grades) were also examined. N-Acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were calculated for all samples. RESULTS: (a) Hamartomas showed higher N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios than gliomas. Hamartomas showed N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios similar to those of healthy volunteers. (b) No significant differences in N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were found in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) N-acetyl aspartate/creatine, creatine/choline, and N-acetyl aspartate/choline ratios were similar for patients who had neurofibromatosis type 1 with and without focal hamartomas and in healthy volunteers. CONCLUSIONS: (a) Hamartomas have a proton MR spectroscopy pattern different from that of glioma and similar to that of normal brain. (b) As performed in this study, proton MR spectroscopy did not show significant differences in patients who had neurofibromatosis type 1 with and without learning disabilities. (c) Patients who have neurofibromatosis type 1 with and without hamartomas seem to have normal intervening brain by proton MR spectroscopy when compared with healthy volunteers.
Adolescent↗
Antibodies to fibrin bound tissue type plasminogen activator in systemic sclerosis.
OBJECTIVE: Abnormalities of tissue type plasminogen activator (tPA) and plasminogen activator inhibitor have been described in some patients with systemic sclerosis (SSc). We studied 128 unselected SSc sera for the presence of autoantibodies to fibrin bound tPA. METHODS: A solid phase fibrin-tPA immunoassay utilized 500 IU/ml tPA bound to solid phase fibrin. Sera diluted 1/50 were incubated with the fibrin bound tPA, the plates were washed, and bound immunoglobulins were detected using polyvalent peroxidase labelled goat antihuman immunoglobulins. Controls included plates coated with fibrin alone or tPA passively adsorbed to the plastic. Sera were considered positive when the A490/630 was above the mean + 2 SD (> 0.055) obtained with normal human serum in 2 independent tests. RESULTS: 25/128 (20%) SSc sera demonstrated antibody reactivity with fibrin bound tPA (mean A490/630 = 0.112). Detailed clinical data were available on 117/128 patients with SSc and on 21/25 anti-tPA positive patients. The mean age of the anti-tPA positive group was 51 yrs and of the anti-tPA negative group 49.6 yrs. Within the anti-tPA positive group there was a significantly higher proportion (p > 0.05) of patients with the CREST (calcinosis, Raynaud's esophageal dysmotility, sclerodactyly, telangiectasias) variant of SSc (7/25 = 28% vs 11/103 = 11%) and pulmonary hypertension (5/21 = 24% vs 6/96 = 6%). CONCLUSION: Our study demonstrates that 20% of unselected patients with SSc have anti-tPA antibodies and that there is a higher representation of patients with CREST syndrome in this subgroup. The high frequency of pulmonary hypertension in the anti-tPA positive group suggests that these autoantibodies may play a pathogenic role in certain patients with SSc.
Adult↗
Conservative management of incontinence.
This review evaluates the main conservative treatments (general measures, physiotherapy, electrostimulation, mechanical devices, and bladder retraining) with particular emphasis on their effectiveness in the management of urinary incontinence. This is difficult because of the paucity of clinical comparison studies using objective end points, and further work needs to be done to establish more clearly the effectiveness of these measures. However, because the therapies are of low risk, relatively low cost and are reversible, they should be included in the counselling of all incontinent patients regarding treatment options.
Female↗
Anterior cervical discectomy and fusion using a porous hydroxyapatite bone graft substitute.
OBJECTIVES: This study analyzed the use of a coral hydroxyapatite bone substitute for use in ACDF both with and without an anterior cervical plate. STUDY DESIGN: The healing of multilevel anterior cervical fusions was tested using a goat model. Comparisons were drawn with histologic, radiographic, and biomechanical test data. METHODS: Forty-nine mature alpine goats had three-level anterior discectomies performed. Seven treatment groups of seven goats each were used; Group I with no fusion, Group IIa having tricortical iliac crest autograft, Group IIb having autograft plus an anterior plate, Group IIIa having tricortical iliac crest fresh-frozen allograft, Group IIIb having allograft plus an anterior plate, Group IVa having rectangular-shaped implants of porous hydroxyapatite, and Group IVb having ProOsteon 500 implants with an anterior cervical plate. RESULTS: Histologically, at 12 weeks 48% of the ProOsteon (Interpore, Irvine, CA) implants were rated as incorporated, 10% as possessing a fibrous gap, 29% as collapsed, and 14% as extruded. Anterior cervical plating improved the results with 71% of the implants showing good incorporation, 24% with collapse, and 5% with a fibrous gap. These histologic results compare favorably with autogenous bone and are improved over allograft bone. Fluorochrome analysis showed that none of the implants had complete turnover with host bone, but that all possessed peripheral creeping substitution with cutting cones of new bone formation at 12 weeks. Biomechanically, the spines using the ProOsteon implant were less stiff in torsion than autograft, but equal in stiffness to allograft. Flexion-extension neutral zone stiffness was lower in the ProOsteon implant group than either allograft or autograft. CONCLUSIONS: The use of a coral-based hydroxyapatite bone graft substitute for anterior cervical fusions led to significant rates of implant collapse at 12 weeks but showed excellent biologic compatibility with good early creeping substitution of the implant by host bone. The concomitant use of an anterior cervical plate with the implant prevents extrusion.
Animals↗
Guanylin activates rat colonic particulate guanylate cyclase.
The polypeptide guanylin is an endogenous activator of small intestinal guanylate cyclase. In rat, guanylin mRNA is found predominantly in intestinal tissues, with its highest abundance in the colon. To date, the effect of guanylin on rat colonic particulate guanylate cyclase, however, has not been examined. It was, therefore, of interest to determine whether the addition of guanylin to intact rat colonocytes, or directly to isolated crude colonic membranes, stimulated guanylate cyclase activity. These studies demonstrated that: 1) rat guanylin, in a concentration-dependent manner, rapidly (within min), but transiently, stimulated particulate guanylate cyclase activity when added to intact colonocytes; 2) guanylin also stimulated guanylate cyclase activity when added directly to isolated colonic membranes; and 3) this latter effect of guanylin on guanylate cyclase activity was increased by ATP or ADP and markedly accentuated by ATP gamma S. Taken together, these results demonstrate that guanylin rapidly stimulates rat colonic particulate guanylate cyclase activity and, moreover, that this effect can be modulated by adenine nucleotides.
Adenosine Triphosphate↗
Vitamin D status modulates rat colonic M3 muscarinic receptor characteristics and coupling to guanylate cyclase.
The present studies were conducted to determine whether [3H]quinuclidinyl benzilate binding in rat colonic membranes and/or carbachol-mediated stimulation of particulate guanylate cyclase were altered by changes in vitamin D status. EC50 values for the stimulation of colonic guanylate cyclase by carbachol were found to be significantly greater in vitamin D-deficient rats compared to their D-sufficient counterparts. Concomitantly, the density of receptors (Bmax) were significantly lower, and dissociation constants (Kd) were significantly higher in D-deficient colonic membranes. In vitamin D-repleted animals, moreover, all of these aforementioned alterations were at least partially corrected.
Animals↗
Capture-recapture as a tool for programme evaluation.
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Data Collection↗
Post-activation potentiation in the neocortex: I. Acute preparations.
Long-term potentiation is widely studied as a memory model, and has been demonstrated in a number of subcortical sites in both acute and chronic preparations. In the neocortex, however, most of the demonstrations of LTP have been in neocortical slice or acute preparations, and even these have often required a drug-induced attenuation of inhibition before the LTP could be reliably expressed. In this paper we show that LTP can be reliably expressed in adult rats in a number of neocortical sites, both ipsilateral and contralateral to the site of callosal stimulation. We also show that, when recording field potentials, LTP is expressed roughly equally at all cortical depths. In a third experiment, we monitored input/output (I/O), paired-pulse inhibition and short-term potentiation effects over the course of LTP induction. The ipsilateral responses were, as expected, of shorter latency and larger amplitude than contralateral responses. They also showed small spike-like components that correlated with cell discharge. Nevertheless, the contralateral responses tended to show the largest LTP effects. The paired pulse effect was mainly depression, lasting for up to 3000 ms, at both ipsilateral and control sites. The short-term potentiation components were best fit by two summed exponentials with time constants of about 70 s and 12 min. The LTP effect lasted at least two h which was the longest period monitored in these experiments.
Animals↗
Post-activation potentiation and depression in the neocortex of the rat: II. Chronic preparations.
Although long-term potentiation (LTP) has been demonstrated in a number of subcortical sites in chronic preparations, there have been no demonstrations of LTP in the neocortex of chronic preparations. Even neocortical slice and acute preparations often require a drug-induced suppression of inhibition before LTP effects can be reliably induced. We have attempted to induce LTP in neocortical sites in 7 different experiments using chronically prepared adult rats. We were unable to obtain any evidence, even a trend, for the induction of LTP. The following manipulations were tested: (1) standard stimulation train parameters that have been shown to be highly effective in subcortical and hippocampal sites; (2) a 10-fold increase in the intra-train pulse durations; (3) variations in train pulse frequency (1 Hz to 300 Hz) and train duration (100 ms to 15 min); (4) co-activation of multiple inputs by stimulation of combinations of cortical sites or cortical and thalamic sites; (5) reduction of inhibition by administration of picrotoxin; 5) Housing of animals in an enriched environment; (6) utilization of the neocortical stimulation trains as a cue in a learning task; (7) application of pilocarpine to co-activate cholinergic systems. Although none of these manipulations produced LTP, the application of pilocarpine did facilitate the induction of a long-lasting depression effect. These findings contrast with the results obtained from anesthetized rats and from studies using brain slices, where LTP can be reliably induced. These results are discussed in light of other recent findings with respect to LTP and LTD effects.
Animals↗
Depression, suicidal ideation, and substance use among adolescents. Are athletes at less risk?
OBJECTIVES: To determine the relationship between participation in high school athletic programs and depression, suicidal ideation, and substance use, and to study the high-risk behaviors of suicidal ideation and substance use. DESIGN: Survey. SETTING: A suburban public high school in Kentucky. PARTICIPANTS: We received 823 (80%) responses from 1030 potential respondents. Athletes (ie, participation on a high school athletic team) were compared with non-athletes. MEASURES: Depression was measured by the Children's Depression Inventory by an index of suicidal ideation by an indicator of a past suicide attempt, and by current use of tobacco, alcohol, marijuana, and cocaine. RESULTS: Thirty percent of the sample participate in school athletic teams. Athletes are less depressed, have less suicidal ideation and attempts, and are less likely to currently smoke cigarettes or marijuana. The use of smokeless tobacco and cocaine was not related to athletic participation. After controlling for demographic characteristics, no difference in alcohol use was found between athletes and nonathletes. CONCLUSIONS: Athletic participation is a marker for a decreased likelihood of depression and some high-risk behaviors in adolescents. Future research could help in creating alternative interventions beyond participation in varsity and junior varsity athletic teams.
Adolescent↗
Receptor-mediated regulation of neuropeptide gene expression in astrocytes.
One of the functions of glial receptors is to regulate synthesis and release of a variety of neuropeptides and growth factor peptides, which in turn act on neurons or other glia. Because of the potential importance of these interactions in injured brain, we have examined the role of two different receptors in the regulation of astrocyte neuropeptide synthesis. Stimulation of beta-adrenergic receptors on type 1 astrocytes resulted in increased mRNA and protein for the proenkephalin (PE) and somatostatin genes. This receptor also increased expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). The potential role of opiate receptors was examined in several ways. Treatment of newborn rats for 7 days with the opiate antagonist naltrexone, prior to preparation of astrocytes, had no effect on PE mRNA or met-enkephalin content but resulted in a significant increase in NGF content. However, treatment of astrocytes in culture with met-enkephalin, morphine, or naltrexone had no effect on any of these parameters. No opiate binding could be detected, using either etorphine or bremazocine, to membranes of astrocytes prepared from cortex, cerebellum, striatum, or hippocampus of 1-day, 7-day, or 14-day postnatal rats. Thus we conclude that type 1 astrocytes do not express opiate receptors and that the in vivo effects of naltrexone are mediated indirectly via some other cell type/receptor.
Adrenergic beta-Agonists↗
Renal function in children and adolescents following 72 g/m2 of ifosfamide.
A detailed analysis of the renal function of 18 children and adolescents aged 7-20 years (median, 16 years) was performed at least 3 months following the completion of a non-platinum-containing chemotherapy regimen with a total dose of 72 g/m2 of ifosfamide. Ifosfamide had been given as a 1-h infusion of 1.8 g/m2 daily for 5 days at 5- to 6-week intervals along with mesna uroprotection. The mean glomerular filtration rate (GFR) as determined by inulin clearance was 100 ml/min/1.73 m2. Although 6 of 18 patients had GFRs below normal, the lowest was only 18% less than the lower limit of normal and would not account for any clinical compromise. The renal plasma flow and filtration fraction were normal. Proximal tubular function evaluation revealed normal fractional excretion (FE) of glucose; normal mean tubular maximum phosphate reabsorption per GFR (TMP)/GFR values; high FE of urate (17%); and mild, generalized aminoaciduria in 6 of the 18 patients. Distal tubular function evaluation showed normal 24-h urinary calcium levels and FE of magnesium as well as normal urinary osmolality after water deprivation. Two patients had mild proteinuria. The findings in this study are encouraging in terms of the lack of clinically significant renal abnormalities observed in patients who had received a cumulative dose of 72 g/m2 of ifosfamide.
Adolescent↗
Visualization of myocardial infarction six hours after injection of 111 In-antimyosin antibodies using an image subtraction technique.
111 In-antimyosin antibodies are capable of visualizing acute myocardial infarction (MI). Because of slow blood clearance, images are usually recorded 24 or 48 h postinjection. This pilot study was aimed at validating a blood pool subtraction technique, which makes it possible to visualize MI 6 h postinjection. Twenty-five patients with proven MI (16 anterior, 9 inferior) were imaged 10 minutes, 6 and 24 h after an injection of 110 MBq 111 In-labelled antimyosin antibodies, with a mean delay of two weeks after infarction. Three planar views were obtained each time. Using software which performs geometric registration, grey level normalization and subtraction of images, the blood pool image (obtained 10 minutes postinjection) was subtracted from the 6 hour image. The resulting image was the blood pool corrected 6 h image. The 24 h images and the blood pool corrected 6 h images were interpreted blindly and the number of correct, incorrect and indeterminate MI localizations were tabulated. The number of correct localizations was 19/25 for the standard 24 h images and 22/25 for the blood pool corrected 6 h images. With this blood pool subtraction method it was possible to visualize MI 6 h postinjection. Theoretically, this method could be applied six hours after myocardial infarction.
Antibodies, Monoclonal↗
Hemorrhage complicating YAG laser feeder vessel coagulation of cornea vascularization.
A neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used in the thermal mode to coagulate blood vessels in a patient with a vascularized corneal leukoma in an attempt to reduce neovascularization before penetrating keratoplasty. Occlusion of the feeder artery at the periphery was followed by a large stromal hemorrhage. A successful keratoplasty was performed 2 days later.
Adult↗
Barriers to nurse practitioner practice.
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Drug Prescriptions↗
Nurse practitioners: the early years (1965-1974)
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Certification↗
Absence of residual effects after physiological stimulation of the visual and motor cortex: an [15O]-H2O PET study in humans.
Cognitive experiments using positron emission tomography (PET) with [15O]-H2O require multiple scans done at 10 to 12 min intervals. Momose and colleagues reported that regional cerebral blood flow changes in response to visual stimulation do not return to baseline even 15 min after the stimulation. If confirmed, this fact would have important implications for the design and interpretation of PET cognitive studies. The purpose of this study was to determine the temporal course of residual effects following visual and motor stimulation. Six healthy volunteers undertook six scans each. Two scans were done to establish a baseline, one to observe the task induced activation, and three scans to investigate the residual effects at varying intervals after the task. The data were analysed using both statistical parametric mapping and a region of interest analysis. The visual and motor task produced robust activations bilaterally in the occipital cortex and in the contralateral primary motor cortex. There was no evidence for a statistically significant residue effect at any of the three intervals studied (30 s, 3 and 6 min). Our results refute the findings of Momose and colleagues and suggest that the 10-min interscan interval is more than adequate to re-establish a resting baseline.
Adult↗