1
|
Affiliation(s)
- K A Gordon
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology-Head & Neck Surgery, University of Toronto, ON, Canada.
| | - B C Papsin
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada; Department of Otolaryngology-Head & Neck Surgery, University of Toronto, ON, Canada
| |
Collapse
|
2
|
Affiliation(s)
- Jacob R Stewart
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Era C Murzaku
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Titilola T Sode
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Katherine A Gordon
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, Texas
| |
Collapse
|
3
|
Kletke S, Batmanabane V, Dai T, Vincent A, Li S, Gordon KA, Papsin BC, Cushing SL, Héon E. The combination of vestibular impairment and congenital sensorineural hearing loss predisposes patients to ocular anomalies, including Usher syndrome. Clin Genet 2017; 92:26-33. [PMID: 27743452 DOI: 10.1111/cge.12895] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 11/29/2022]
Abstract
The co-occurrence of hearing impairment and visual dysfunction is devastating. Most deaf-blind etiologies are genetically determined, the commonest being Usher syndrome (USH). While studies of the congenitally deaf population reveal a variable degree of visual problems, there are no effective ophthalmic screening guidelines. We hypothesized that children with congenital sensorineural hearing loss (SNHL) and vestibular impairment were at an increased risk of having USH. A retrospective chart review of 33 cochlear implants recipients for severe to profound SNHL and measured vestibular dysfunction was performed to determine the ocular phenotype. All the cases had undergone ocular examination and electroretinogram (ERG). Patients with an abnormal ERG underwent genetic testing for USH. We found an underlying ocular abnormality in 81.81% (27/33) of cases; of which 75% had refractive errors, and 50% of those patients showed visual improvement with refractive correction. A total of 14 cases (42.42%; 14/33) had generalized rod-cone dysfunction on ERG suggestive of Usher syndrome type 1, confirmed by mutational analysis. This work shows that adding vestibular impairment as a criterion for requesting an eye exam and adding the ERG to detect USH increases the chances of detecting ocular anomalies, when compared with previous literature focusing only on congenital SNHL.
Collapse
Affiliation(s)
- S Kletke
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - V Batmanabane
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - T Dai
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - A Vincent
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - S Li
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - K A Gordon
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - B C Papsin
- Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - S L Cushing
- Department of Otolaryngology - Head & Neck Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada.,Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - E Héon
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada.,Program of Genetics and Genomic Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| |
Collapse
|
4
|
Stewart JR, Gordon KA, Condie D, Agim NG. Hyperkeratotic plaques on the trunk and extremities. J Am Acad Dermatol 2017. [DOI: 10.1016/j.jaad.2016.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
5
|
Turrentine JE, Gordon KA, Agim NG. Blaschkoid Skin Lesions in a Young Girl. JAMA Dermatol 2016; 152:713-4. [PMID: 26963772 DOI: 10.1001/jamadermatol.2016.0061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jake E Turrentine
- Division of Dermatology, The Medical College of Georgia at Augusta University, Augusta
| | | | - Nnenna G Agim
- The University of Texas at Southwestern Medical Center, Dallas3Children's Medical Center, Dallas, Texas
| |
Collapse
|
6
|
Merdad M, Wolter NE, Cushing SL, Gordon KA, Papsin BC. Surgical efficiency in bilateral cochlear implantation: A cost analysis. Cochlear Implants Int 2013; 15:43-7. [DOI: 10.1179/1754762813y.0000000042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
7
|
Forbes MS, Thornhill BA, Galarreta CI, Minor JJ, Gordon KA, Chevalier RL. Chronic unilateral ureteral obstruction in the neonatal mouse delays maturation of both kidneys and leads to late formation of atubular glomeruli. Am J Physiol Renal Physiol 2013; 305:F1736-46. [PMID: 24107422 DOI: 10.1152/ajprenal.00152.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Unilateral ureteral obstruction (UUO) in the adult mouse is the most widely used model of progressive renal disease: the proximal tubule is the nephron segment most severely affected and atubular glomeruli are formed after only 7 days of UUO. To determine the proximal nephron response to UUO in the maturing kidney, neonatal mice were examined 7 to 28 days following complete UUO under general anesthesia. Proximal tubular mass and maturation were determined by staining with Lotus tetragolonobus lectin. Superoxide was localized by nitroblue tetrazolium and collagen by Sirius red. Cell proliferation, cell death, PAX-2, megalin, α-smooth muscle actin (α-SMA), renin, and fibronectin were identified by immunohistochemistry. During the first 14 days of ipsilateral UUO, despite oxidative stress (4-hydroxynonenal staining), glomerulotubular continuity was maintained and mitochondrial superoxide production persisted. However, from 14 to 28 days, papillary growth was impaired and proximal tubules collapsed with increased apoptosis, autophagy, mitochondrial loss, and formation of atubular glomeruli. Fibronectin, α-SMA, and collagen increased in the obstructed kidney. Oxidative stress was present also in the contralateral kidney: renin was decreased, glomerulotubular maturation and papillary growth were delayed, followed by increased cortical and medullary growth. We conclude that neonatal UUO initially delays renal maturation and results in oxidative stress in both kidneys. In contrast to the adult, proximal tubular injury in the neonatal obstructed kidney is delayed at 14 days, followed only later by the formation of atubular glomeruli. Antioxidant therapies directed at proximal tubular mitochondria during early renal maturation may slow progression of congenital obstructive nephropathy.
Collapse
Affiliation(s)
- Michael S Forbes
- Dept. of Pediatrics, Univ. of Virginia, Box 800386, Charlottesville, VA 22908.
| | | | | | | | | | | |
Collapse
|
8
|
Stojadinovic O, Landon JN, Gordon KA, Pastar I, Escandon J, Vivas A, Maderal AD, Margolis DJ, Kirsner RS, Tomic-Canic M. Quality assessment of tissue specimens for studies of diabetic foot ulcers. Exp Dermatol 2013; 22:216-8. [PMID: 23489425 DOI: 10.1111/exd.12104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2013] [Indexed: 12/20/2022]
Abstract
Diabetic foot ulcers (DFUs) represent an important clinical problem resulting in significant morbidity and mortality. Ongoing translational research studies strive to better understand molecular/cellular basis of DFU pathology that may lead to identification of novel treatment protocols. Tissue at the non-healing wound edge has been identified as one of major contributors to the DFU pathophysiology that provides important tool for translational and clinical investigations. To evaluate quality of tissue specimens and their potential use, we obtained 81 DFU specimens from 25 patients and performed histological analyses, immunohistochemistry and RNA quality assessments. We found that depth of the collected specimen is important determinant of research utility, and only specimens containing a full-thickness epidermis could be utilized for immunohistochemistry and RNA isolation. We showed that only two-thirds of collected specimens could be utilized in translational studies. This attrition rate is important for designs of future studies involving tissue specimen collection from DFU.
Collapse
|
9
|
Hopyan T, Gordon KA, Papsin BC. Identifying emotions in music through electrical hearing in deaf children using cochlear implants. Cochlear Implants Int 2013; 12:21-6. [DOI: 10.1179/146701010x12677899497399] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
10
|
Forbes MS, Thornhill BA, Minor JJ, Gordon KA, Galarreta CI, Chevalier RL. Fight-or-flight: murine unilateral ureteral obstruction causes extensive proximal tubular degeneration, collecting duct dilatation, and minimal fibrosis. Am J Physiol Renal Physiol 2012; 303:F120-9. [PMID: 22535799 DOI: 10.1152/ajprenal.00110.2012] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Unilateral ureteral obstruction (UUO) is the most widely used animal model of progressive renal disease. Although renal interstitial fibrosis is commonly used as an end point, recent studies reveal that obstructive injury to the glomerulotubular junction leads to the formation of atubular glomeruli. To quantitate the effects of UUO on the remainder of the nephron, renal tubular and interstitial responses were characterized in mice 7 and 14 days after UUO or sham operation under anesthesia. Fractional proximal tubular mass, cell proliferation, and cell death were measured by morphometry. Superoxide formation was identified by nitro blue tetrazolium, and oxidant injury was localized by 4-hydroxynonenol and 8-hydroxydeoxyguanosine. Fractional areas of renal vasculature, interstitial collagen, α-smooth muscle actin, and fibronectin were also measured. After 14 days of UUO, the obstructed kidney loses 19% of parenchymal mass, with a 65% reduction in proximal tubular mass. Superoxide formation is localized to proximal tubules, which undergo oxidant injury, apoptosis, necrosis, and autophagy, with widespread mitochondrial loss, resulting in tubular collapse. In contrast, mitosis and apoptosis increase in dilated collecting ducts, which remain patent through epithelial cell remodeling. Relative vascular volume fraction does not change, and interstitial matrix components do not exceed 15% of total volume fraction of the obstructed kidney. These unique proximal and distal nephron cellular responses reflect differential "fight-or-flight" responses to obstructive injury and provide earlier indexes of renal injury than do interstitial compartment responses. Therapies to prevent or retard progression of renal disease should include targeting proximal tubule injury as well as interstitial fibrosis.
Collapse
Affiliation(s)
- Michael S Forbes
- Division of Pediatric Nephrology, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
| | | | | | | | | | | |
Collapse
|
11
|
Stojadinovic O, Gordon KA, Lebrun E, Tomic-Canic M. Stress-Induced Hormones Cortisol and Epinephrine Impair Wound Epithelization. Adv Wound Care (New Rochelle) 2012; 1:29-35. [PMID: 24527275 DOI: 10.1089/wound.2011.0320] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Stress-induced disruption of hormonal balance in animals and humans has a detrimental effect on wound healing. THE PROBLEM After the injury, keratinocytes migrate over the wound bed to repair a wound. However, their nonmigratory phenotype plays a role in pathogenesis of chronic wounds. Despite many therapeutic approaches, there is a dearth of treatments targeting the molecular mechanisms mediated by stress that prevent epithelization. BASIC/CLINICAL SCIENCE ADVANCES Recent studies show that epidermal keratinocytes synthesize stress hormones. During acute wound healing, cortisol synthesis in the epidermis is tightly controlled. Further, a key intermediate molecule in the cholesterol synthesis pathway, farnesyl pyrophosphate (FPP), can bind glucocorticoid receptor (GR) and activate GR. Additionally, keratinocytes express beta-2-adrenergic-receptor (β2AR), a receptor for the stress hormone epinephrine. Importantly, migratory rates of keratinocytes are reduced by cortisol, FPP, epinephrine, and other β2AR agonists, thus indicating their role in the inhibition of epithelization. Topical inhibition of local glucocorticoid and FPP synthesis, as well as treatment with β2AR antagonists promotes wound epithelization. CLINICAL CARE RELEVANCE Modulation of local stress hormone production may represent an important therapeutic target for wound healing disorders. Topical administration of inhibitors of cortisol synthesis, statins, β2AR antagonists, and systemic beta-blockers can decrease cortisol synthesis, FPP, and epinephrine levels, respectively, thus restoring keratinocyte migration capacity. These treatment modalities could represent a novel therapeutic approach for wound healing disorders. CONCLUSION Attenuation of the local stress-induced hormonal imbalance in epidermis may advance therapeutic modalities, thereby leading to enhanced epithelization and improved wound healing.
Collapse
Affiliation(s)
- Olivera Stojadinovic
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Katherine A. Gordon
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Elizabeth Lebrun
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Marjana Tomic-Canic
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida
| |
Collapse
|
12
|
Abstract
Bilateral cochlear implants (CIs) have been provided to children who are deaf in both ears with intent to promote binaural hearing. If it is possible to establish binaural hearing with two CIs, these children would be able to make use of interaural level and timing differences to localize sound and to distinguish between sounds separated in space. These skills are central to the ability to attend to one particular sound amidst a number of sound sources. This may be particularly important for children because they are typically learning and interacting in groups. However, the development of binaural processing could be disrupted by effects of bilateral deafness, effects of unilateral CI use, or issues related to the child's age at onset of deafness and age at the time of the first and second cochlear implantation. This research aims to determine whether binaural auditory processing is affected by these variables in an effort to determine the optimal timing for bilateral cochlear implantation in children. It is now clear that the duration of bilateral deafness should be limited in children to restrict reorganization in the auditory thalamo-cortical pathways. It has also been shown that unilateral CI use can halt such reorganization to some extent and promote auditory development. At the same time, however, unilateral input might compromise the development of binaural processing if CIs are provided sequentially. Mismatches in responses from the auditory brainstem and cortex evoked by the first and second CI after a long period of unilateral CI use suggest asymmetry in the bilateral auditory pathways which is significantly more pronounced than in children receiving bilateral implants simultaneously. Moreover, behavioural responses to level and timing differences between implants suggest that these important binaural cues are not being processed normally by children who received a second CI after a long period of unilateral CI use and at older ages. In sum, there may be multiple sensitive periods in the developing auditory system, which must be considered when determining the optimal timing for bilateral cochlear implantation.
Collapse
Affiliation(s)
- K A Gordon
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, Toronto, ON, Canada.
| | | | | |
Collapse
|
13
|
Gordon KA, Lebrun EA, Tomic-Canic M, Kirsner RS. The role of surgical debridement in healing of diabetic foot ulcers. Skinmed 2012; 10:24-26. [PMID: 22324173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A critical question in the treatment of chronic wounds is whether and when debridement is needed. The three most common chronic wounds are the diabetic foot ulcer (DFU), the venous leg ulcer, and the pressure or decubitus ulcer. Surgical debridement, aimed at removing necrotic, devitalized wound bed and wound edge tissue that inhibits healing, is a longstanding standard of care for the treatment of chronic, nonhealing wounds. Debridement encourages healing by converting a chronic nonhealing wound environment into a more responsive acute healing environment. While the rationale for debridement seems logical, the evidence to support its use in enhancing healing is scarce. Currently, there is more evidence in the literature for debridement for DFUs than for venous ulcers and pressure ulcers; however, the studies on which clinicians have based their rationale for debridement in DFUs possess methodologic flaws, small sample sizes, and bias. Thus, further studies are needed to develop clinical evidence for its inclusion in treatment protocols for chronic wounds. Here, the authors review the scientific evidence for debridement of DFUs, the rationale for debridement of DFUs, and the insufficient data supporting debridement for venous ulcers and pressure ulcers.
Collapse
Affiliation(s)
- Katherine A Gordon
- Department of Dermatology & Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | | | | |
Collapse
|
14
|
Abstract
Hair loss is a very common complaint. Patients may describe increased shedding and diffuse or localized alopecia. The differential diagnosis of hair loss includes a number of disorders causing cicatricial or noncicatricial alopecias. This paper describes the clinical approaches and diagnostic tests that are useful in the evaluation of patients presenting with alopecia. It also reviews treatments for noncicatricial alopecias, including androgenetic alopecia, alopecia areata, and telogen effluvium, as well as cicatricial alopecias, including lichen planopilaris, its clinical variant frontal fibrosing alopecia, and discoid lupus erythematosus.
Collapse
Affiliation(s)
- Katherine A Gordon
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | | |
Collapse
|
15
|
Gordon KA, Wong DDE, Valero J, Jewell SF, Yoo P, Papsin BC. Use it or lose it? Lessons learned from the developing brains of children who are deaf and use cochlear implants to hear. Brain Topogr 2011; 24:204-19. [PMID: 21479928 DOI: 10.1007/s10548-011-0181-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 03/26/2011] [Indexed: 11/24/2022]
Abstract
In the present paper, we review what is currently known about the effects of deafness on the developing human auditory system and ask: Without use, does the immature auditory system lose the ability to normally function and mature? Any change to the structure or function of the auditory pathways resulting from a lack of activity will have important implications for future use through an auditory prosthesis such as a cochlear implant. Data to date show that deafness in children arrests and disrupts normal auditory development. Multiple changes to the auditory pathways occur during the period of deafness with the extent and type of change being dependent upon the age and stage of auditory development at onset of deafness, the cause or type of deafness, and the length of time the immature auditory pathways are left without significant input. Structural changes to the auditory nerve, brainstem, and cortex have been described in animal models of deafness as well in humans who are deaf. Functional changes in deaf auditory pathways have been evaluated by using a cochlear implant to stimulate the auditory nerve with electrical pulses. Studies of electrically evoked activity in the immature deaf auditory system have demonstrated that auditory brainstem development is arrested and that thalamo-cortical areas are vulnerable to being taken over by other competitive inputs (cross-modal plasticity). Indeed, enhanced peripheral sight and detection of visual movement in congenitally deaf cats and adults have been linked to activity in specific areas of what would normally be auditory cortex. Cochlear implants can stimulate developmental plasticity in the auditory brainstem even after many years of deafness in childhood but changes in the auditory cortex are limited, at least in part, by the degree of reorganization which occurred during the period of deafness. Consequently, we must identify hearing loss rapidly (i.e., at birth for congenital deficits) and provide cochlear implants to appropriate candidates as soon as possible. Doing so has facilitated auditory development in the thalamo-cortex and allowed children who are deaf to perceive and use spoken language.
Collapse
Affiliation(s)
- K A Gordon
- Archie's Cochlear Implant Laboratory, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario, Canada.
| | | | | | | | | | | |
Collapse
|
16
|
Gordon KA, Tanaka S, Wong DDE, Papsin BC. Characterizing responses from auditory cortex in young people with several years of cochlear implant experience. Clin Neurophysiol 2008; 119:2347-62. [PMID: 18752993 DOI: 10.1016/j.clinph.2008.06.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2006] [Revised: 06/19/2008] [Accepted: 06/22/2008] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To determine if cortical responses evoked by a cochlear implant in children who are deaf differ from normal and to characterize these differences in children who achieve good versus fair speech perception outcomes post-implantation. METHODS Late latency-evoked potential responses were recorded at 28 scalp locations in 16 children who were deaf from infancy and experienced cochlear implant users. Speech perception measures indicated that 8 had good scores and 8 had fair scores. In each child, responses were evoked by 36ms electrical pulse trains delivered from a single-implant electrode at the apical and basal ends of the array and by 36ms tone bursts (0.5, 2, and 6kHz). Responses to the tone bursts were also recorded in 14 age-matched children with normal hearing. RESULTS We found (1) a dominant positive wave in all implant users and (2) a larger than normal negative amplitude peak in users with fair speech perception scores which had similar scalp topography to N1 but did not show the expected changes in amplitude with stimulus frequency. CONCLUSIONS Late latency-evoked potential responses in children using cochlear implants reflect abnormal and/or immature patterns of cortical activity. SIGNIFICANCE Limitations in auditory skills with a cochlear implant in children may be due to developmental processes in the cortex which are either slow to mature or which mature abnormally.
Collapse
Affiliation(s)
- K A Gordon
- The Cochlear Implant Program, The Cochlear Implant Laboratory, Room 6D08, The Hospital for Sick Children, 555 University Avenue, Toronto, Ont., Canada M5G 1X8.
| | | | | | | |
Collapse
|
17
|
Gordon KA, Valero J, Papsin BC. Auditory brainstem activity in children with 9–30 months of bilateral cochlear implant use. Hear Res 2007; 233:97-107. [PMID: 17850999 DOI: 10.1016/j.heares.2007.08.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 07/29/2007] [Accepted: 08/01/2007] [Indexed: 10/23/2022]
Abstract
Bilateral cochlear implants aim to restore binaural processing along the auditory pathways in children with bilateral deafness. We assessed auditory brainstem activity evoked by single biphasic pulses delivered by an apical or basal electrode from the left, right and both cochlear implants in 13 children. Repeated measures were made over the first 9-30 months of bilateral implant use. In children with short or long periods of unilateral implant use prior to the second implantation, Wave eV of the auditory brainstem response was initially prolonged when evoked by the naïve versus experienced side. These differences tended to resolve in children first implanted <3 years of age but not in children implanted at older ages with long delays between implants. Latency differences were projected to persist for longer periods in children with long delays between implants compared with children with short delays. No differences in right versus left evoked eV latency were found in 2 children receiving bilateral implants simultaneously and their response latencies decreased over time. Binaural interaction responses showed effects of stimulating electrode position (responses were more detectable when evoked by an apical than basal pair of implant electrodes), and duration of delay between implants (measured by latency delays). The trends shown here suggest a negative impact of unilateral implant use on bilateral auditory brainstem plasticity.
Collapse
Affiliation(s)
- K A Gordon
- Cochlear Implant Laboratory, The Hospital for Sick Children, Room 6D08, 555 University Avenue, Toronto, ON, Canada M5G 1X8.
| | | | | |
Collapse
|
18
|
Gordon KA, Papsin BC, Harrison RV. Auditory brainstem activity and development evoked by apical versus basal cochlear implant electrode stimulation in children. Clin Neurophysiol 2007; 118:1671-84. [PMID: 17588811 DOI: 10.1016/j.clinph.2007.04.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 04/17/2007] [Accepted: 04/30/2007] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The role of apical versus basal cochlear implant electrode stimulation on central auditory development was examined. We hypothesized that, in children with early onset deafness, auditory development evoked by basal electrode stimulation would differ from that evoked more apically. METHODS Responses of the auditory nerve and brainstem, evoked by an apical and a basal implant electrode, were measured over the first year of cochlear implant use in 50 children with early onset severe to profound deafness who used hearing aids prior to implantation. RESULTS Responses at initial stimulation were of larger amplitude and shorter latency when evoked by the apical electrode. No significant effects of residual hearing or age were found on initial response amplitudes or latencies. With implant use, responses evoked by both electrodes showed decreases in wave and interwave latencies reflecting decreased neural conduction time through the brainstem. Apical versus basal differences persisted with implant experience with one exception; eIII-eV interlatency differences decreased with implant use. CONCLUSIONS Acute stimulation shows prolongation of basally versus apically evoked auditory nerve and brainstem responses in children with severe to profound deafness. Interwave latencies reflecting neural conduction along the caudal and rostral portions of the brainstem decreased over the first year of implant use. Differences in neural conduction times evoked by apical versus basal electrode stimulation persisted in the caudal but not rostral brainstem. SIGNIFICANCE Activity-dependent changes of the auditory brainstem occur in response to both apical and basal cochlear implant electrode stimulation.
Collapse
Affiliation(s)
- K A Gordon
- Cochlear Implant Laboratory, the Hospital for Sick Children, and Department of Otolaryngology-Head and Neck Surgery, University of Toronto, Ontario, Canada.
| | | | | |
Collapse
|
19
|
Abstract
OBJECTIVES Physician opinions and practice patterns regarding the participation of children and adolescents with single, normal kidneys in contact/collision sports are widely varied. We hypothesize that limitation of participation from play based only on the presence of a single kidney is not supported by available data. We sought to determine recommendations of pediatric nephrologists regarding the participation of patients with single, normal kidneys in contact/collision sports and review the literature to determine the rate of sports-related kidney injury compared with other organs. METHODS Members of the American Society of Pediatric Nephrology were surveyed regarding their recommendations for participation of patients with single, normal kidneys in contact/collision sports. Medical and sports literature databases were searched to determine sports-related kidney, brain, spinal cord, and cardiac injury rates and the sports associated with kidney injury. RESULTS Sixty-two percent of respondents would not allow contact/collision sports participation. Eighty-six percent of respondents barred participation in American football, whereas only 5% barred cycling. Most cited traumatic loss of function as the reason for discouraging participation. The literature search found an incidence of catastrophic sports-related kidney injury of 0.4 per 1 million children per year from all sports. Cycling was the most common cause of sports-related kidney injury causing > 3 times the kidney injuries as football. American football alone accounted for 0.9 to 5.3 fatal brain injuries and 4.9 to 7.3 irreversible spinal cord injuries per 1 million players per year. Commotio cordis causes 2.1 to 9.2 deaths per year. CONCLUSIONS Most pediatric nephrologists prohibit contact/collision sports participation by athletes with a single kidney, particularly football. The available evidence suggests that cycling is far more likely to cause kidney injury. In addition, kidney injury from sports is much less common than catastrophic brain, spinal cord, or cardiac injury. Restricting participation of patients with a single, normal kidney from contact/collision sports is unwarranted.
Collapse
Affiliation(s)
- Matthew M Grinsell
- Department of Pediatrics, Division of Nephrology, University of Virginia, 1224 Jefferson Park Ave, Suite 701, Charlottesville, Virginia 22903, USA.
| | | | | | | |
Collapse
|
20
|
Jones RN, Gordon KA, Biedenbach DJ. Comparisons of the in vitro susceptibility testing results for garenoxacin using six different national methods: report from the garenoxacin international bridging study. J Antimicrob Chemother 2004; 53:258-65. [PMID: 14729758 DOI: 10.1093/jac/dkh060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Laboratories worldwide carry out MIC/disc diffusion (DD) tests using various national methods, often published by local organizations. Potentially different results may complicate drug development or registration between the US methods and those used in the European Union (EU). This study uses a new des-F(6)quinolone, garenoxacin, to compare in vitro results among the most utilized antimicrobial susceptibility testing methods. METHODS Investigators in France, Germany, Spain, Sweden and the UK tested two bacterial collections designated, challenge (CC; n = 330) containing quinolone-resistant strains and national (NC; n = 540) that were recent clinical isolates (2000-2001). Results were compared with values derived from the National Committee for Clinical Laboratory Standards (NCCLS) methods, carried out by the US coordinating site. Discords (greater than four-fold) between MIC method results were repeated. Results were analysed for variation from the NCCLS results (+/-1-2 dilutions or greater than 3-6 mm) and by regression statistics. Ciprofloxacin was used as the control quinolone agent. RESULTS CC and NC testing compliance averaged 98.4% and 86.4% among participating centres, respectively, and correlation (r) of the national method to the NCCLS MIC was: France (0.98), Germany (0.95), Spain (0.98), Sweden (0.96) and UK (0.95). CC produced MIC results that were identical to the NCCLS (Spain) to 0.6 x log(2) greater (Germany), but the percentage of strains +/-2 dilutions versus NCCLS MIC results was 98% (Germany)-100% (Sweden, UK). Similar patterns were observed for the NC (r = 0.93-0.98), and all nations had >99% of results within +/-2 dilutions (+/-6 mm for disc tests) of NCCLS values. MIC results from four national methods were slightly elevated compared to the NCCLS result (average 0.2 x log(2)). Control ciprofloxacin MIC and DD test results showed similar patterns. CONCLUSIONS Inter-method garenoxacin susceptibility test results indicate that MIC and zone diameter endpoints derived from five EU methods compare favourably to the NCCLS method results, and generally were identical or a fraction of a log(2) dilution step higher. In contrast, zone diameters for garenoxacin and ciprofloxacin were routinely larger for the EU methods. This unique inter-method 'bridging' experiment allows regulatory agencies to better correlate in vitro testing results derived from procedures that use different national methodologies.
Collapse
Affiliation(s)
- R N Jones
- The JONES Group/JMI Laboratories, Inc., 345 Beaver Kreek Centre, Suite A, North Liberty, IA 52317, USA.
| | | | | |
Collapse
|
21
|
Pfaller MA, Beach ML, Gordon KA, Jones RN. Comparative antimicrobial spectrum and activity of BMS284756 (T-3811; a desfluoroquinolone) tested against an international collection of staphylococci and enterococci, including in vitro test development and intermethod comparisons. J Chemother 2002; 14:13-8. [PMID: 11892893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The study was initiated to determine the in vitro activity and MIC/disk test comparisons of BMS284756, a new des-fluoro(6)-quinolone, against isolates of staphylococci and enterococci from the SENTRY Antimicrobial Surveillance Program, 2000. Isolates were tested by reference broth microdilution and standardized disk diffusion methods. Against 3,789 strains of gram-positive cocci from the SENTRY Program (2000), the BMS284756 MIC90 and percentage susceptible at < or = 2 and < or = 4 microg/ml were: Staphylococcus aureus (4 microg/ml; 89.3 and 97.1%), coagulase-negative staphylococci (CoNS; 4 microg/ml; 86.1 and 96.0%) and enterococci (> 4 microg/ml; 62.0 and 76.2%). Also tested were selected staphylococci (300 strains) and enterococci (102 strains) by two standardized methods. The activity of BMS284756 was highly correlated with oxacillin resistance among staphylococci. Oxacillin-susceptible staphylococci were all inhibited by BMS284756 at < or = 0.5 microg/ml, whereas oxacillin-resistant strains required inhibitory concentrations of > or = 1 microg/ml. Excellent correlation was observed between the MIC and 5-microg disk zone diameter for staphylococci and enterococci (r=0.91 to 0.93). Among vancomycin-susceptible enterococci, 67% of Enterococcus faecalis, 25% of E. faecium, and 76% of other Enterococcus spp. isolates were inhibited by BMS284756 at < or = 2 microg/ml. All vancomycin-resistant enterococci (VRE; 11 E. faecalis and 15 E. faecium) were inhibited by > or = 2 microg/ml of BMS284756. Among the non-VRE, non-faecium enterococcal isolates (n=64), 62% were inhibited by < or = 0.5 microg/ml. BMS284756 showed excellent activity against oxacillin-susceptible staphylococci and moderate activity against enterococci other than VRE and E. faecium. Acceptable correlations were observed between MIC and disk test results for both tested genus groups.
Collapse
Affiliation(s)
- M A Pfaller
- University of Iowa College of Medicine, Iowa City, USA
| | | | | | | |
Collapse
|
22
|
Gordon KA, Fusco J, Biedenbach DJ, Pfaller MA, Jones RN. Antimicrobial susceptibility testing of clinical isolates of Bordetella pertussis from northern California: report from the SENTRY Antimicrobial Surveillance Program. Antimicrob Agents Chemother 2001; 45:3599-600. [PMID: 11709347 PMCID: PMC90876 DOI: 10.1128/aac.45.12.3599-3600.2001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Reports of an increased clinical incidence of pertussis and the development of resistance by Bordetella pertussis to erythromycin prompted the collection and testing of recent clinical isolates from patients in northern California against a range of antimicrobial agents by the Etest (AB BIODISK, Solna, Sweden) method. All isolates were fully susceptible to all eight agents tested (MIC, <or=0.38 microg/ml), including newer fluoroquinolones, such as gatifloxacin (MIC of which 90% of the isolates tested are inhibited, 0.006 microg/ml), which may be used in cases of adolescent or adult pertussis. Continued surveillance of B. pertussis isolates appears to be a prudent practice.
Collapse
Affiliation(s)
- K A Gordon
- University of Iowa College of Medicine, Iowa City, Iowa 52242, USA
| | | | | | | | | |
Collapse
|
23
|
Richter SS, Gordon KA, Rhomberg PR, Pfaller MA, Jones RN. Neisseria meningitidis with decreased susceptibility to penicillin: report from the SENTRY antimicrobial surveillance program, North America, 1998-99. Diagn Microbiol Infect Dis 2001; 41:83-8. [PMID: 11687319 DOI: 10.1016/s0732-8893(01)00289-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to estimate the prevalence of Neisseria meningitidis with decreased susceptibility to penicillin (MIC, >0.06 microg/mL) in North America (NA). Antimicrobial susceptibility testing by Etest (AB BIODISK, Solna, Sweden) was performed on 53 invasive clinical isolates obtained from 11 SENTRY Antimicrobial Surveillance Program participants in NA (9 states, 2 provinces) during 1998-99. All strains were markedly susceptible to ciprofloxacin (MIC(90), 0.008 microg/mL) and cefotaxime (MIC(90), < or = 0.002 microg/mL). Only 54.7% were susceptible to trimethoprim-sulfamethoxazole (TMP/SMX) at < or = 0.5/9.5 microg/mL. One strain was resistant to rifampin (MIC, > 32 microg/mL) and 16 isolates (30.2%) were relatively resistant to penicillin with MICs ranging from 0.094 to 0.25 microg/mL. No beta-lactamase production was detected. The serogroup distribution was 40% Y, 28% B, 24% C, 2% W-135, and 6% of strains were nongroupable. The prevalence of N. meningitidis with decreased susceptibility to penicillin in NA appears higher than previous reports.
Collapse
Affiliation(s)
- S S Richter
- Medical Microbiology Division, Department of Pathology, University of Iowa College of Medicine, Iowa City, Iowa, USA.
| | | | | | | | | |
Collapse
|
24
|
Gordon KA, Twitchell KA, Papsin BC, Harrison RV. Effect of residual hearing prior to cochlear implantation on speech perception in children. J Otolaryngol 2001; 30:216-23. [PMID: 11771033 DOI: 10.2310/7070.2001.20157] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We examined the impact of residual hearing prior to cochlear implantation on pre- and postimplantation speech perception outcomes in children. Stimulation of the auditory system prior to implantation because of the presence of residual hearing is important for development of the central auditory pathways, whereas, in the absence of such stimulation, the pathways show less development. We hypothesized that children who had some degree of residual hearing preimplantation achieve better speech perception skills than their peers with poorer hearing. From the 133 children followed in our program, we identified 37 children who had an audiometric pure-tone average of better than 95 dB HL in the better ear at any time preimplantation. Psychophysical speech perception measures, the Word Identification Picture Inventory and the Phonetically Balanced Kindergarten list, in these children were compared with those of 96 implanted children who had poorer hearing prior to implantation. Children with more residual hearing showed higher speech perception scores both before implantation and over their first year of implant use than children with poorer hearing, suggesting that there is an advantage in having a greater degree of residual hearing preimplantation. We suggest that this advantage is promoted, in part, by the greater potential for auditory stimulation provided by high-gain hearing aids in children with greater degrees of residual hearing. This advantage appears to be maintained at least over 1 year postimplantation, yet the rates of development of postimplantation speech perception are not different between the groups. We suggest that this may be due to the unique aspects of electrical stimulation from a cochlear implant. Our findings suggest that it is important to minimize the delay of speech perception skills in the preimplantation phase, particularly in children with poor residual hearing. This can be accomplished by implanting children with congenital severe to profound hearing loss at young ages and children with acquired hearing loss soon after the onset. Also, auditory stimulation prior to implantation should be maximized through the consistent use of hearing aids and therapy that emphasizes development of auditory skills.
Collapse
Affiliation(s)
- K A Gordon
- Department of Otolaryngology, The Hospital for Sick Children, Toronto, Ontario
| | | | | | | |
Collapse
|
25
|
Abstract
Cochlear implants have enabled many children with severe to profound sensorineural hearing loss to develop speech perception skills. However, some children experience few gains while others develop high levels of speech perception. We identified potential factors contributing to poor performance with an implant by studying implanted children who do not develop functional speech perception. Five children were identified as developing no open-set word recognition skills after at least 2 years of implant use. This study group was compared to a randomly selected control group (n=10) and an age-matched control group (n=5). Pre-implant factors were examined using a Graded Profile Analysis and post-implant factors were assessed in a retrospective chart review. A greater number of pre-implant concerns were raised in the study group than in randomized controls (P<0.01). Chronological age and duration of deafness were pre-implant concerns in all study group subjects. A greater number of post-implant concerns were found in the study group than in randomly selected controls (P<0.005). We conclude that while appropriate selection of candidates for cochlear implantation is important in predicting speech perception outcomes, post-implant follow-up is also essential and must include regular monitoring of equipment, monitoring of stimulation levels with use of objective measures of stimulation levels if necessary, and consistent habilitation.
Collapse
Affiliation(s)
- K A Gordon
- Department of Otolaryngology and the Cochlear Implant Program, The Hospital for Sick Children, 555 University Avenue, M5G 1X8, Toronto, ON, Canada
| | | | | | | |
Collapse
|
26
|
Gales AC, Jones RN, Pfaller MA, Gordon KA, Sader HS. Two-year assessment of the pathogen frequency and antimicrobial resistance patterns among organisms isolated from skin and soft tissue infections in Latin American hospitals: results from the SENTRY antimicrobial surveillance program, 1997-98. SENTRY Study Group. Int J Infect Dis 2000; 4:75-84. [PMID: 10737843 DOI: 10.1016/s1201-9712(00)90098-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES This study was conducted to evaluate the frequency of occurrence and antimicrobial susceptibility of bacterial isolates collected from patients with skin and soft tissue infections (SSTI) in Latin American hospitals, as part of the SENTRY Antimicrobial Surveillance Program. The dissemination of multidrug-resistant methicillin-resistant Staphylococcus aureus (MDR-MRSA) among the Latin American countries also was studied. MATERIAL AND METHODS A total of 885 bacterial isolates were analyzed. At the monitoring laboratory, antimicrobial susceptibility testing utilizing the reference broth microdilution method and confirmation of species identification were performed. Enterobacteriaceae possibly producing extended-spectrum beta-lactamases (ESBL) and MDR-MRSA isolates were genotyped by ribotyping using the RiboPrinter and by pulsed-field gel electrophoresis. RESULTS Staphylococcus aureus (31%) was the most common etiologic agent causing SSTI, followed by Escherichia coli (13.4%) and Pseudomonas aeruginosa (11%). Thirty-one percent of S. aureus isolates were resistant to oxacillin (methicillin). The presence of ESBL phenotypes was markedly higher among the Klebsiella pneumoniae (35.5%) than E. coli isolates (10. 2%). Meropenem was the compound with the highest susceptibility rate among the Enterobacteriaceae (100%) and P. aeruginosa (95%) isolates. A great genetic similarity was observed among the MDR-MRSA in Latin America. CONCLUSION High resistance rates to antimicrobial drugs among the most frequent bacterial pathogens were observed in 10 medical centers in Latin America. This study also demonstrated a clonal dissemination of a MDR-MRSA strain in several nations.
Collapse
Affiliation(s)
- A C Gales
- Medical Microbiology Division, Department of Pathology, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
| | | | | | | | | |
Collapse
|
27
|
Gales AC, Jones RN, Gordon KA, Sader HS, Wilke WW, Beach ML, Pfaller MA, Doern GV. Activity and spectrum of 22 antimicrobial agents tested against urinary tract infection pathogens in hospitalized patients in Latin America: report from the second year of the SENTRY antimicrobial surveillance program (1998). J Antimicrob Chemother 2000; 45:295-303. [PMID: 10702547 DOI: 10.1093/jac/45.3.295] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The potency and spectrum of various antimicrobial agents tested against 434 bacterial isolates causing urinary tract infection (UTI) in hospitalized patients in Latin America were evaluated. The genotypes of the extended-spectrum beta-lactamase-producing and selected multi-resistant isolates were also evaluated by molecular typing techniques. Escherichia coli (60.4%) was the most common aetiological agent causing UTI, followed by Klebsiella spp. (11.2%) and Pseudomonas aeruginosa (8.3%). In contrast, Enterococcus spp. isolates caused only 2.3% of UTIs. Fewer than 50% of E. coli isolates were susceptible to broad-spectrum penicillins. The resistance rates to ciprofloxacin and the new quinolones were also high among these isolates. The molecular characterization of ciprofloxacin-resistant E. coli showed that most of them have a double mutation in the gyrA gene associated with a single mutation in the parC gene. The Klebsiella pneumoniae isolates studied demonstrated high resistance rates to beta-lactam drugs, including broad-spectrum cephalosporins. The carbapenems were the compounds with the highest susceptibility rate among these isolates (100.0% susceptible) followed by cefepime (91.7% susceptible). Meropenem, imipenem and cefepime were also the most active drugs against Enterobacter spp. Among P. aeruginosa isolates, meropenem (MIC(50), 2 mg/L) was the most active compound, followed by imipenem (MIC(50), 4 mg/L), cefepime (MIC(50), 8 mg/L) and ceftazidime (MIC(50), 16 mg/L). The results presented in this report confirm that bacterial resistance continues to be a great problem in Latin American medical institutions.
Collapse
Affiliation(s)
- A C Gales
- Medical Microbiology Division, 251 MRC, Department of Pathology, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Gales AC, Gordon KA, Wilke WW, Pfaller MA, Jones RN. Occurrence of single-point gyrA mutations among ciprofloxacin-susceptible Escherichia coli isolates causing urinary tract infections in Latin America. Diagn Microbiol Infect Dis 2000; 36:61-4. [PMID: 10744370 DOI: 10.1016/s0732-8893(99)00121-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To detect if isolates susceptible to quinolones already carry mutations in the gyrA and parC genes, we selected 12 ciprofloxacin-susceptible Escherichia coli strains collected from patients with urinary tract infections in Latin America in 1998, as part of ongoing SENTRY Antimicrobial Surveillance Program. The isolates studied exhibited minimal inhibitory concentrations (MICs) for ciprofloxacin between < or = 0.015 microg/mL and 0.5 microg/mL. The molecular characterization of quinolone resistance was determinated by amplification of the gyrA and parC by PCR followed by sequencing of the respective amplicons. We observed that E. coli isolates exhibiting MIC, < or = 0.06 microg/mL for ciprofloxacin did not show mutations in either topoisomerase. On the other hand, all isolates with MIC between 0.12 microg/mL and 0.5 microg/mL demonstrated single mutation in the gyrA gene. The most frequent mutation occurred at position 83, where the amino acid serine was replaced by leucine. No mutations in the parC gene were observed. To preserve the potency and prevent the development of resistance, we suggest that quinolone usage should be rational, especially in the treatment of urinary tract infections, and in the prophylaxis of immunosupressed patient populations.
Collapse
Affiliation(s)
- A C Gales
- Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
| | | | | | | | | |
Collapse
|
29
|
Genovese RF, Newman DB, Gordon KA, Brewer TG. Acute high dose arteether toxicity in rats. Neurotoxicology 1999; 20:851-9. [PMID: 10591521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Acute high dose administration of the artemisinin antimalarial, beta-arteether (AE), was evaluated in rats using an auditory discrimination task (ADT) and histology. After rats were trained on the ADT, AE (25, 75, 125 mg/kg, i.m.) or vehicle (sesame oil) was administered and behavioral performance was evaluated for 11 consecutive days. Histological evaluation of the brains was performed using thionine and cupric-silver staining. Damaged cells were counted in specific brainstem nuclei of all rats and a qualitative analysis of the rostral-caudal extent of selected brains was performed. Behavioral performance was not significantly affected by any treatment although some evidence of disruption was observed, particularly after the largest dose. At 125 mg/kg, AE produced statistically significant neuropathology, including chromatolysis, in the nucleus trapezoideus and nucleus superior olive. AE at 75 mg/kg, produced significant neuropathology in the nucleus trapezoideus. Neither AE at 25 mg/kg, nor vehicle produced damage. Qualitative analysis revealed a pattern of neuropathology focused in the brainstem. The results show that, in rats, a single dose of AE can produce a pattern of brainstem neuropathology and that specific brainstem nuclei, including auditory nuclei, are particularly vulnerable. These results are consistent with, and extend, previous studies demonstrating brainstem neurotoxicity from repeated AE administration. Moreover, early detection of AE-induced neuropathology is problematic and may require selective examination of brainstem functions.
Collapse
Affiliation(s)
- R F Genovese
- Division of Neurosciences, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
| | | | | | | |
Collapse
|
30
|
Daya H, Figueirido JC, Gordon KA, Twitchell K, Gysin C, Papsin BC. The role of a graded profile analysis in determining candidacy and outcome for cochlear implantation in children. Int J Pediatr Otorhinolaryngol 1999; 49:135-42. [PMID: 10504020 DOI: 10.1016/s0165-5876(99)00112-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Assessment of candidacy for cochlear implantation in children continues to present a challenge to cochlear implant programs. The efficacy of implantation depends on a number of factors and as a result a multidisciplinary approach has been adopted. At the Cochlear Implant Program at The Hospital for Sick Children, Toronto, we use a graded profile analysis (GPA) which has been adapted from the Children's Implant Profile (CHIP) developed by Hellman (S.A. Hellman, P.M. Chute, R.E. Kretschmer, M.E., Nevins, S.C. Parisier, L.C. Thurston, The development of a Children's Implant Profile, Am. Ann. Deaf. 136 (1991) 77-81). This structured assessment allows each potential candidate to be 'scored' in each category of assessment giving a potential range of -14 to +14. In this retrospective study of 109 candidates we examine the relationship between GPA scores and decision to implant. For those patients who were implanted, the relationship between GPA score and speech perception outcomes was also evaluated. Three distinct groups of children emerged from the analysis. The first group had scores less than 5 and were not considered to be suitable for implantation. Within the second group who scored between 5 and 8, there was no clear relationship between decision to implant and score. The last group, who scored 9-14, was considered to be generally suitable for implantation provided that there were no medical contraindications and the parents consented to implantation. There was a significant association between rate of improvement of speech perception and GPA score. Those patients with scores of 9 to +14 improved at a faster rate than group 5-8 (P < 0.05). The implications of these findings are discussed.
Collapse
Affiliation(s)
- H Daya
- Department of Otolaryngology, The Hospital for Sick Children, Toronto, ON, Canada
| | | | | | | | | | | |
Collapse
|
31
|
Abstract
The syntheses and immunosuppressive activity of ruthenium complexes are described. One of the complexes (1a) was shown to be a potent inhibitor of human T-lymphocyte proliferation with an IC50 of 5 nM. The activity of these complexes compares favorably to the well known immunosuppressants Cyclosporin A and Rapamycin.
Collapse
|
32
|
Ocain TD, Bastos CM, Gordon KA, Granstein RD, Jenson JC, Jones B, McAuliffe DJ, Newcomb JR. A novel series of low molecular weight immunosuppressive agents. Transplant Proc 1996; 28:3032-4. [PMID: 8962176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- T D Ocain
- Procept, Inc, Cambridge, MA 02139, USA
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Beginning in 1985, an ACHA task force studied national health objectives to determine how well colleges and universities were achieving nationally defined health goals. The task force found that the college-aged population was not specifically recognized as a concern among health planners and that little consistent data on the health status of students existed. The task force worked closely with federal agencies in identifying relevant issues and focusing on the higher education community's commitment to disease promotion and positive health behaviors.
Collapse
|
34
|
Charlson ME, Allegrante JP, Hollenberg JP, Szatrowski TP, Peterson MG, Robbins L, Gordon KA, MacKenzie CR, Williams-Russo P, Paget SA. An organizational model for developing multidisciplinary clinical research in the academic medical center. Arthritis Rheum 1993; 36:741-9. [PMID: 8507214 DOI: 10.1002/art.1780360602] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To assess the impact of a new organizational model designed to stimulate multidisciplinary clinical research. METHODS We conducted a prospective, 3 1/2-year followup of a research training program for residents, fellows, faculty, nurses, and allied health professionals in rheumatology and orthopedic surgery. Program components included a multidisciplinary clinical research conference, a clinical research methods curriculum, consultations, a patient registry, and regular meetings of a Research Methodology Core group. Measures included participation in each program component and the number of new investigators who developed funded clinical research projects. RESULTS The multidisciplinary clinical research conference was attended by 369 new health professionals; 218 professionals participated in at least one of the courses; and 280 consultations were provided to 108 professionals. Thirteen new investigators developed 17 new grant proposals, of which 14 were externally funded. Investigators who successfully procured funding for new projects demonstrated significantly more participation in program components compared with those who did not (P < 0.001 overall). CONCLUSION Participation in the program was significantly correlated with the development of new prospective patient-based studies. We conclude that our model has the potential to foster such research in other settings.
Collapse
Affiliation(s)
- M E Charlson
- Department of Medicine, Cornell Arthritis and Musculoskeletal Disease Center, New York, NY 10021
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Claude P, Parada IM, Gordon KA, D'Amore PA, Wagner JA. Acidic fibroblast growth factor stimulates adrenal chromaffin cells to proliferate and to extend neurites, but is not a long-term survival factor. Neuron 1988; 1:783-90. [PMID: 3272188 DOI: 10.1016/0896-6273(88)90126-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Acidic fibroblast growth factor (aFGF) is a heparin-binding polypeptide that is a mitogen for endothelial cells and glial cells, as well as a differentiation factor for PC12 cells and certain neurons. We show here that aFGF is as potent as nerve growth factor (NGF) in stimulating both neuritic outgrowth and proliferation in adrenal chromaffin cells from young rats, but it fails to support long-term survival. Heparin strongly potentiates aFGF-dependent neuritic outgrowth but not aFGF-dependent proliferation. As is the case with NGF, phorbol myristate acetate depresses aFGF-induced cell division and increases the outgrowth of neurites. On the other hand, dexamethasone antagonizes neuritic outgrowth elicited by both NGF and aFGF but inhibits only proliferation induced by NGF. The effects of basic FGF (bFGF) are similar but not identical to those of aFGF. Thus the regulatory pathways controlled by aFGF, bFGF, and NGF are partially distinct.
Collapse
Affiliation(s)
- P Claude
- Wisconsin Regional Primate Research Center, University of Wisconsin, Madison 53715
| | | | | | | | | |
Collapse
|
36
|
Azanaur'ian MS, Gordon KA. [Treatment of patients with diseases of veins of the lower extremities at the Sochi-Matsesta health resort]. Voen Med Zh 1970; 1:74-6. [PMID: 4245235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|