A Type II Split Cord Malformation in an Adult Patient: An Operative Case Report

BACKGROUND AND IMPORTANCE

Split cord malformations (SCMs) are rare conditions in which the spinal cord is split into two hemicords within either a single thecal sac or two separate thecal sacs. The hemicords are typically split by a bony or fibrous structure. We present an adult patient who presented with a type II SCM with tethered cord. This is the first case of such a presentation with an accompanying intraoperative video. Unusual features of the case were the presence of an incomplete fibrous septum and lack of a discrete filum terminale.

CLINICAL PRESENTATION

A 50-yr-old woman presented with back pain, radiculopathy, urinary urgency, and episodic fecal incontinence. Her exam was notable for weakness of the right extensor hallicus longus. Imaging showed an SCM extending from L3 to S1, a fibrous septum located at L4-5, and a low-lying conus at S4. She was treated with a decompressive L3-S4 laminectomy and disconnection of all the dural attachment points. She required lumbar drain placement postoperatively and reoperation for wound dehiscence and persistent pseudomeningocele. At the time of last follow-up, she was neurologically intact with improvement in bowel/bladder function.

CONCLUSION

SCM is an uncommon presentation in adults and is often accompanied by findings of skin stigmata, tethered cord, and other central nervous system/skeletal anomalies. Obtaining full multimodal imaging is critical to understanding subtle anatomic variations that can pose operative challenges. We report the treatment of an adult patient with type II SCM, and provide an intraoperative video demonstrating the removal of an incomplete midline fibrous septum.

0837 Well-Being Predicts Sleep Disturbance in a Prospective Cohort of Older Adults

Introduction

Lower well-being negatively impacts health among older adults. Optimal sleep - a determinant of health - has been associated with higher well-being. Several domains of well-being, e.g., mindfulness and purpose in life have been shown to improve sleep. But, whether well-being impacts sleep remains unclear. This study examined associations between well-being and sleep duration, sleep quality, and incident insomnia symptoms among a nationally representative sample of older US adults.

Methods

This study analyzed data from the 2011-2013 National Health and Aging Trends Study (NHATS), a longitudinal, annual survey of community-dwelling Medicare beneficiaries. The exposure, a validated scale of well-being used questions on purpose, emotion, and self-satisfaction and divided responses into quartiles. Sleep outcomes included sleep duration, sleep quality, and insomnia symptoms. Unadjusted and adjusted linear and logistic regression models examined relationships between the health characteristics and well-being score in 2012 and sleep outcomes in 2013. Covariates included demographics and health characteristics.

Results

Half of study participants (n=2,000) were women. The mean sleep duration was 7.2 and 7.3 (standard error(SE) ±0.1) for men and women. Poor sleep quality was reported by 30% of subjects and more frequently among Hispanic subjects, older adults, and those with less education. The mean well-being score was 17.2 (SE ±0.07). Higher well-being scores correlated with male gender, younger age, higher education, marriage, and increased physical activity. Well-being scores in the 2nd - 4th quartile had lower odds of poor sleep quality (4th quartile adjusted odd ratio 0.24 (95% CI 0.15, 0.38). The highest well-being quartile had a 4-fold lower incidence of insomnia symptoms. Well-being scores were not associated with sleep duration

Conclusion

Higher well-being may protect older adults against the development of insomnia and poor sleep quality. Strategies to improve well-being could offer an innovative way to improve the health of older Americans though better sleep.

Support

none

1131 Obstructive Sleep Apnea Treatment and Dementia Risk in Older Adults

Introduction

Obstructive Sleep Apnea (OSA) has been linked to dementia and Alzheimer’s Disease (AD), as well as pre-dementia. The potential benefits of OSA treatment on cognitive performance are inconclusive. Further, the impact of OSA treatment on the development of neurodegenerative disorders has not been sufficiently studied. This study examined associations between Positive Airway Pressure (PAP) therapy and incident diagnosis of pre-dementia (MCI), dementia (DNOS), or AD in a population-level sample of older adults.

Methods

Using a random 5% sample from Medicare claims data (persons age 65 and older), individuals with an ICD-9 diagnosis code for OSA prior to 2011 (n=53,321) were selected for analyses. Over the survey period (2011-2013), we further identified persons newly diagnosed with MCI (n=443), DNOS (n=378), or AD (n=1,057). We also identified individual HCPCS claims for PAP equipment as evidence of prescription, and repeated HCPCS claims for supplies as evidence of adherence to PAP treatment. Logistic regression models were used to adjust for potential confounders including age, gender, hypertension, and Parkinson’s Disease that might increase risk for dementia.

Results

Seventy-eight percent of beneficiaries with OSA were prescribed PAP, and 74% showed evidence of adherent use. After adjustment for potential confounders, prescription of PAP was associated with significantly lower odds of incident AD and DNOS (OR=0.78, 95% CI: 0.69, 0.89; and OR=0.69, 95% CI: 0.55, 0.85). Lower odds of MCI, approaching statistical significance, were also observed among beneficiaries who were prescribed PAP (OR=0.82, (95% CI: 0.66, 1.02). Evidence of adherence to PAP was significantly associated with lower odds of incident AD (OR=0.65, 95% CI: 0.56, 0.76).

Conclusion

Among older individuals with OSA, PAP prescription and adherence are each associated with a significantly lower risk of incident AD or DNOS, though not MCI. Although a prospective cohort design cannot prove causality, results suggest that treatment of OSA could reduce risk of subsequent dementia.

Support

This study was supported by The American Academy of Sleep Medicine Foundation Strategic Research Award 115-SR-15 (PI Braley).

0654 Obstructive Sleep Apnea in Older Adults: Geographic Variation in CPAP Treatment

Introduction

Obstructive sleep apnea (OSA) is prevalent and consequential among older adults. Positive airway pressure (PAP) is likely to reduce associated morbidity, but adherence is inconsistent. Regional treatment variations that may reflect addressable differences in care are not sufficiently studied. We examined geographic variations in PAP treatment among older US adults.

Methods

A representative 5% sample of all Medicare beneficiaries, age 65+, enrolled in fee-for-service program in 2013 was analyzed. OSA diagnosis was defined by ICD-9 codes. PAP treatment was identified by HCPCS codes. Treatment adherence was defined as ≥2 HCPCS claims for PAP supplies on separate months. We examined state-specific proportions of Medicare beneficiaries with OSA who obtained PAP and showed adherence. Maps were created to represent state-specific proportions of beneficiaries who were treated and adherent, by quantiles. To examine more granular regional variations, we created maps representing hospital referral region (HRR)-specific proportions of treated among diagnosed, and adherent among treated. Scatterplots were used to identify the relationship between proportions of PAP treatment and adherence, by state.

Results

For the state-level data, PAP treatment and adherence rates were between 54%-87% and 59%-81%, respectively. Midwest states had higher CPAP treatment proportions (>80%), while Northeast, Southwest and Southern states had CPAP treatment rates <73%. State-level CPAP adherence showed similar patterns, with lowest rates in southern states and California (<70%). Within-state variability of treatment patterns were observed, especially along the east and the west coasts. A scatterplot revealed that state-level CPAP treatment and adherence rates were linearly correlated, with Washington D.C., NY and NJ ranked lowest. In contrast, MT, ND and VT had the highest treatment and adherence rates.

Conclusion

These data show substantial state-level and regional variability of CPAP treatment and adherence among Medicare beneficiaries. Some geographic areas may merit prioritization in efforts to improve OSA treatment and adherence.

Support

This study was supported by The American Sleep Medicine Foundation Strategic Research Award 115-SR-15

Methods for implantation of micro-wire bundles and optimization of single/multi-unit recordings from human mesial temporal lobe

OBJECTIVE

The authors report methods developed for the implantation of micro-wire bundles into mesial temporal lobe structures and subsequent single neuron recording in epileptic patients undergoing in-patient diagnostic monitoring. This is done with the intention of lowering the perceived barriers to routine single neuron recording from deep brain structures in the clinical setting.

APPROACH

Over a 15 month period, 11 patients were implanted with platinum micro-wire bundles into mesial temporal structures. Protocols were developed for (A) monitoring electrode integrity through impedance testing, (B) ensuring continuous 24-7 recording, (C) localizing micro-wire position and 'splay' pattern and (D) monitoring grounding and referencing to maintain the quality of recordings.

MAIN RESULTS

Five common modes of failure were identified: (1) broken micro-wires from acute tensile force, (2) broken micro-wires from cyclic fatigue at stress points, (3) poor in vivo micro-electrode separation, (4) motion artifact and (5) deteriorating ground connection and subsequent drop in common mode noise rejection. Single neurons have been observed up to 14 days post-implantation and on 40% of micro-wires.

SIGNIFICANCE

Long-term success requires detailed review of each implant by both the clinical and research teams to identify failure modes, and appropriate refinement of techniques while moving forward. This approach leads to reliable unit recordings without prolonging operative times, which will help increase the availability and clinical viability of human single neuron data.

Effect of insurance status on postacute care among working age stroke survivors

OBJECTIVE

Utilization of postacute care is associated with improved poststroke outcomes. However, more than 20% of American adults under age 65 are uninsured. We sought to determine whether insurance status is associated with utilization and intensity of institutional postacute care among working age stroke survivors.

METHODS

A retrospective cross-sectional study of ischemic stroke survivors under age 65 from the 2004-2006 Nationwide Inpatient Sample was conducted. Hierarchical logistic regression models controlling for patient and hospital-level factors were used. The primary outcome was utilization of any institutional postacute care (inpatient rehabilitation or skilled nursing facilities) following hospital admission for ischemic stroke. Intensity of rehabilitation was explored by comparing utilization of inpatient rehabilitation facilities and skilled nursing facilities.

RESULTS

Of the 33,917 working age stroke survivors, 19.3% were uninsured, 19.8% were Medicaid enrollees, and 22.8% were discharged to institutional postacute care. Compared to those privately insured, uninsured stroke survivors were less likely (adjusted odds ratio [AOR] 0.53, 95% confidence interval [CI] 0.47-0.59) while stroke survivors with Medicaid were more likely to utilize any institutional postacute care (AOR = 1.40, 95% CI 1.27-1.54). Among stroke survivors who utilized institutional postacute care, uninsured (AOR = 0.48, 95% CI 0.36-0.64) and Medicaid stroke survivors (AOR = 0.27, 95% CI 0.23-0.33) were less likely to utilize an inpatient rehabilitation facility than a skilled nursing facility compared to privately insured stroke survivors.

CONCLUSIONS

Insurance status among working age acute stroke survivors is independently associated with utilization and intensity of institutional postacute care. This may explain differences in poststroke outcomes among uninsured and Medicaid stroke survivors compared to the privately insured.

Enrollment of women and minorities in NINDS trials

OBJECTIVE

To determine policy-associated changes over time in 1) the enrollment of women and minorities in National Institute of Neurological Disorders and Stroke (NINDS)-funded clinical trials and 2) the trial publication reporting of race/ethnicity and gender.

METHODS

All NINDS-funded phase III trials published between 1985 and 2008 were identified. Percent of African Americans, Hispanic Americans, and women enrolled in the trials was calculated for those trials with available data. Z tests were used to compare reporting and enrollment data from before (period 1) and after (period 2) 1995 when NIH enacted their policies regarding race, ethnicity, and gender. Percent of main trial publications reporting enrollment of African Americans, Hispanic Americans, and women was also calculated.

RESULTS

Of the 56 trials identified, 100%, 48%, and 25% reported enrollment by gender, race, and ethnicity. Women constituted 42.1% of the trial population. Enrollment of women increased over time (36.9% period 1; 49.0% period 2, p < 0.001). African Americans constituted 19.8% of the enrollees in trials with available data and enrollment increased over time (11.6% period 1; 30.7% period 2, p < 0.001). Hispanic Americans constituted 5.8% of subjects in trials with available data and enrollment decreased over time (7.4% period 1; 5.0% period 2, p < 0.001).

CONCLUSIONS

Improvements in reporting of race/ethnicity in publications and enrollment of Hispanics in NINDS trials are needed. While African American representation is above population levels, Hispanic Americans are underrepresented in NINDS trials and representation is declining despite Hispanics' increasing representation in the US population.

Critical analysis of a computer-assisted tutorial on ECG interpretation and its ability to determine competency

BACKGROUND

We developed a computer-based tutorial and a posttest on ECG interpretation for training residents and determining competency.

METHODS

Forty residents, 6 cardiology fellows, and 4 experienced physicians participated. The tutorial emphasized recognition and understanding of abnormal ECG features. Active learning was promoted by asking questions prior to the discussion of ECGs. Interactivity was facilitated by providing rapid and in-depth rationale for correct answers. Responses to questions were recorded and extensively analyzed to determine the quality of questions, baseline knowledge at different levels of training and improvement of grades in posttest. Posttest grades were used to assess improvement and to determine competency.

RESULTS

The questions were found to be challenging, fair, appropriate and discriminative. This was important since the quality of Socratic questions is critical for the success of interactive programs. The information on strengths and weakness in baseline knowledge at different levels of training were used to adapt our training program to the needs of residents. The posttest revealed that the tutorial contributed to marked improvement in feature recognition. Competency testing distinguished between residents with outstanding grades and those who needed remediation.

CONCLUSIONS

The strategy for critical evaluation of our computer program could be applied to any computer-based educational program, regardless of topic.

Crystallization and preliminary X-ray studies of recombinant horseradish peroxidase

A non-glycosylated form of horseradish peroxidase c extracted from Escherichia coli inclusion bodies and refolded in the presence of haem and Ca(2+) ions has been used to grow protein crystals suitable for X-ray diffraction analysis. The crystals are prisms in the trigonal space group P3(1)12 or P3(2)12 with a = b = 158.9 and c = 114.3 A, and diffract to 1.9 A. There are four molecules, each of 34 kDa, in the asymmetric unit. The molecules of the asymmetric unit are related by approximate translational symmetry, resulting in pseudo-centerings. Data to approximately 15 A can thus be described by a lattice of a' = b' = 91.7 A and c' = 57.1 A, alpha = beta = 90 degrees and gamma = 120 degrees, including four molecules.

Identification of low-abundance differentially expressed transcripts using arrayed cDNA clones

Analysis of comparative gene expression by the use of DNA microarrays has become a widely used tool. However, this technique is only readily applied to organisms where sequence information is known. This paper describes the development of a low-cost method of gene discovery by enrichment of differentially expressed transcripts, which uses cDNA library arrays of bacterial clones on nylon membranes (macroarrays) coupled with a subtractive probe preparation method to discover differentially expressed genes. The method requires no prior knowledge of the organism's genome sequence and overcomes the inherent insensitivity of standard methods of macroarray hybridisation.

Regulation of the pharynx of Caenorhabditis elegans by 5-HT, octopamine, and FMRFamide-like neuropeptides

More than fifty FMRFamide-like neuropeptides have been identified in nematodes. We addressed the role of a subset of these in the control of nematode feeding by electrophysiological recording of the activity of C. elegans pharynx. AF1 (KNEFIRFamide), AF2 (KHEYLRFamide), AF8 (KSAYMRFamide), and GAKFIRFamide (encoded by the C. elegans genes flp-8, flp-14, flp-6, and flp-5, respectively) increased pharyngeal action potential frequency, in a manner similar to 5-HT. In contrast, SDPNFLRFamide, SADPNFLRFamide, SAEPFGTMRFamide, KPSVRFamide, APEASPFIRFamide, and AQTVRFamide (encoded by the C. elegans genes flp-1; flp-1; flp-3; flp-9; flp-13, and flp-16, respectively) inhibited the pharynx in a manner similar to octopamine. Only three of the neuropeptides had potent effects at low nanomolar concentrations, consistent with a physiological role in pharyngeal regulation. Therefore, we assessed whether these three peptides mediated their actions either directly on the pharynx or indirectly via the neural circuit controlling its activity by comparing actions between wild-type and mutants with deficits in synaptic signaling. Our data support the conclusion that AF1 and SAEPFGTMRFamide regulate the activity of the pharynx indirectly, whereas APEASPFIRFamide exerts its action directly. These results are in agreement with the expression pattern for the genes encoding the neuropeptides (Kim and Li, 1999) as both flp-8 and flp-3 are expressed in extrapharyngeal neurons, whereas flp-13 is expressed in I5, a neuron with synaptic output to the pharyngeal muscle. These results provide the first, direct, functional information on the action of neuropeptides in C. elegans. Furthermore, we provide evidence for a putative inhibitory peptidergic synapse, which is likely to have a role in the control of feeding.

The initial attitudes of patients toward longer maintenance hemodialysis

Longer hemodialysis (HD) as practiced in parts of Europe and Japan may improve both blood pressure control and patient survival. Nevertheless, in the USA, the trend has been to shorten dialysis time using larger dialyzers and increased blood flows. Many patients find the notion of shorter dialysis enticing. Most are unaware ofthe potential benefits of longer dialysis. We surveyed stable chronic HD patients in an urban area, the vast majority of whom received conventional 4-hour treatments, regarding their attitude toward extending their dialysis time to 5 hours. They were informed that longer dialysis has been associated with better blood pressure control and improved survival. One hundred and sixteen patients completed questionnaires during a single dialysis session. Forty-six (40%) agreed to extended dialysis while 70 (60%) did not. There was no difference between the groups with respect to the following variables: age, race, etiology of ESRD, time on dialysis, marital status, number of children at home, number residing in the household, education, or employment status. Male gender was associated with a positive response (p = 0.03). Various suggested and spontaneous reasons were given for a negative response.

CONCLUSION

With minimally detailed information, 4 in 10 patients were willing to extend their treatment time to 5 hours in the hope of improving morbidity and survival. No sociodemographic variable except gender was associated with a positive response.

Neuronal expression of an FMRFamide-gated Na+ channel and its modulation by acid pH

The molluscan Phe-Met-Arg-Phe-amide (FMRFamide)-gated sodium channels (FaNaCs) show both structural and functional similarities to the mammalian acid-sensing ion channels (ASICs). Both channel types are related to the epithelial sodium channels and, although the neuropeptide FMRFamide directly gates the FaNaCs, it also modulates the proton-gating properties of ASICs. It is not yet known whether protons can alter the gating properties of the FaNaCs. We chose to examine this possibility at a site of FaNaC expression in the nervous system of the mollusk Lymnaea stagnalis. We cloned a putative L. stagnalis FaNaC (LsFaNaC) that exhibited a high degree of sequence identity to the Helix aspersa FaNaC (HaFaNaC, 60%), and a weaker homology to the ASICs (ASIC3, 22%). In situ hybridization was used to map the LsFaNaC expression pattern in the brain and to identify the right pedal giant1 (RPeD1) neuron as a site where the properties of the endogenous channel could be studied. In RPeD1 neurons isolated in culture, we demonstrated the presence of an FMRFamide-gated sodium current with features expected for a FaNaC: amiloride sensitivity, sodium selectivity, specificity for FMRFamide and Phe-Leu-Arg-Phe-amide (FLRFamide), and no dependency on G-protein coupling. The sodium current also exhibited rapid desensitization in response to repeated FMRFamide applications. Lowering of the pH of the bathing solution reduced the amplitude of the FMRFamide-gated inward current, while also activating an additional sustained weak inward current that was apparently not mediated by the FaNaC. Acidification also prevented the desensitization of the FMRFamide-induced inward current. The acid sensitivity of LsFaNaC is consistent with the hypothesis that FaNaCs share a common ancestry with the ASICs.

Effect of anti-transforming growth factor-beta antibodies in cyclosporine-induced renal dysfunction

BACKGROUND

Several experimental and clinical studies have implicated a role for transforming growth factor-beta (TGF-beta) in mediating the nephrotoxic effects of cyclosporine (CsA). To test this hypothesis, we administered neutralizing anti-TGF-beta antibodies (alpha-TGF-beta) in a well-described rat model of chronic CsA nephrotoxicity.

METHODS

We studied three groups (N = 9 per group) of adult, male Sprague-Dawley rats that received a low-salt diet (0.05% sodium). Normal controls were given vehicle subcutaneously and an alternate-day intraperitoneal injection of 3 mg of nonspecific mouse IgG (MIgG) for 28 days. The CsA group received 15 mg/kg/day of CsA subcutaneously and 3 mg of MIgG intraperitoneally on alternate days for 28 days. The CsA/alpha-TGF-beta group received CsA and alternate-day alpha-TGF-beta (3 mg) for 28 days. At the end of 28 days, creatinine clearance was measured by 24-hour urine collection. Histologic assessment was performed for tubulointerstitial damage and arteriolar hyalinosis. Northern analysis was performed for alpha 1(I) collagen and TGF-beta 1 gene expression, and quantitative reverse transcription-polymerase chain reaction was performed to measure levels of tissue inhibitor of metalloproteinase-1 (TIMP-1), TIMP-2, plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-2 (MMP-2), and MMP-9.

RESULTS

CsA-treated rats had significantly lower creatinine clearance as compared with normal controls (0.43 +/- 0.07 vs. 0.67 +/- 0.14 mL/min, P = 0.0002), increased interstitial damage and afferent arteriolar hyalinosis (P = 0.0001), and increased alpha1(I) collagen (4-fold) and TGF-beta 1 (2.5-fold) mRNA expression. CsA-treated rats also had significantly increased TIMP-1 (7.4-fold, P < 0.001), MMP-2, and PAI-1 (all approximately 2-fold, P < 0.02) and decreased MMP-9 (85% reduction, P < 0.001) as compared with controls. Treatment with alpha-TGF-beta in CsA-treated rats significantly prevented the reduction in creatinine clearance (0.58 +/- 0.03 mL/min, P = 0.009 vs. CsA alone), the increase in afferent arteriolar hyalinosis (P < 0.05 vs. CsA alone), normalized alpha 1(I) collagen mRNA levels, and attenuated CsA effects on TGF-beta1, TIMP-1, and MMP-9.

CONCLUSIONS

In this rat model of CsA-induced nephrotoxicity, renal insufficiency and characteristic histologic changes are associated with altered expression of matrix and matrix-regulating molecules. Based on our results with alpha-TGF-beta antibodies, many but not all of these nephrotoxic effects of CsA are mediated by TGF-beta.

Werner's syndrome T lymphocytes display a normal in vitro life-span

Werner's syndrome (WS) is an autosomal recessive disorder displaying many features consistent with accelerated ageing. Fibroblasts from WS patients show a distinct mutator phenotype (characterised by the production of large chromosomal deletions) and a profound reduction in proliferative capacity. The disorder results from a mutation in a novel ReqQ helicase. Recently, we demonstrated that the proliferative defect was corrected by the ectopic expression of telomerase. From these data, we propose that mutations in the wrn gene lead to deletions at or near the telomere which reduce the cells replicative life-span. This hypothesis predicts that cell types which retain the ability to upregulate telomerase as part of their response to a proliferative stimulus would fail to show any significant effect of wrn gene mutations upon life-span. Human T lymphocytes represent a well-characterised example of such a cell type. To test the hypothesis, WS T lymphocytes were cultured until they reached replicative senescence. These cultures displayed life-spans which did not differ significantly from those of normal controls. These findings are consistent with the hypothesis that the effects of wrn mutations on replicative life-span are telomere-mediated.

Multimeric CREB-binding sites in the promoter regions of a family of G-protein-coupled receptors related to the vertebrate galanin and nociceptin/orphanin-FQ receptor families

Four related genes encoding a family of G-protein-coupled receptors (GPCRs) have been isolated from the mollusc Lymnaea stagnalis. The coding regions of this family of receptors share 97-99% sequence similarity at both the protein and nucleotide level, and they also share high sequence identity with vertebrate galanin and orphanin-FQ/nociceptin GPCR families. Analysis of the promoter regions reveals shared domains, some of which encode highly conserved repeating units. One 27-bp repeating unit, which encodes a c-AMP response element (CRE) and binds CREB protein, is repeated 14 times in one promoter. In situ hybridization showed expression of these receptors in identified neurons of several behaviourly important networks including those involved in feeding and ion and water regulation. These Lymnaea receptors are likely to represent members of a novel family of invertebrate neuropeptide receptors extensively regulated in response to intracellular signalling cascades.

Artificial skin

The skin is a complex organ that is difficult to replace when it is irreversibly damaged by burns, trauma, or disease. Although autologous skin transplantation remains the most common form of treatment in patients with significant skin loss, there are now a number of commercially available products that can be used to replace the skin temporarily or permanently. Here we describe several such products under the rubric "artificial skin," focusing on two types of technology that have been applied to the problem of permanent skin replacement.

Reflections on tissue engineering and trauma therapy

Although all of Trauma Care has remarkably improved during the latter half of the last century the treatment of burn injury has substantially out paced other areas and serves as an excellent example illustrating the improvements taking place in the treatment of injured patients. Although Trauma treatment lagged behind the rest of medicine in mid-century today it rests solidly on the cutting edge of advancing therapeutic knowledge and practice in areas of metabolism, immunology, infection control, critical care, tissue engineering and the delivery of clinical care. It is important to understand what has happened to allow the treatment of injury to be so effective. The bench mark therapeutic moves that have had major effects allowing the present highly effective treatment are: immediate tailored fluid resuscitation, preventive (prophylactic) and topical antibiotics, metabolically designed nutritional therapy and most important early definitive repair of the injury. All must be delivered early after trauma if they are to be optimally effective in preventing the complications of injury that are devastating if encountered. Unfortunately, all problems are not solved by todays treatment of injury, improved as it is. These problems are largely related to an inexact understanding: of the physiologic changes of aging, of the exact pathophysiologic events in inhalation injury and multisystem organ failure and of the technology required to replace those body parts damaged by the injury itself that lead to death or to healing with loss of function. There will be major improvements in the understanding and ability to effectively deal with the problems of aging and inhalation injury through basic and clinical research but perhaps the major improvement in injury treatment will come through the ability to replace worn out, defective or damaged body parts through technologies that resemble regeneration. Here the concepts of Tissue Engineering have much to contribute and it is worth exploring the donation of Tissue Engineering to dermal replacement following burn injury to serve as an example of what types of additions to treatment Tissue Engineering can make.

Association of IgA nephropathy with Clostridium difficile colitis

Immunoglobulin A (IgA) nephropathy, the most common cause of glomerulonephritis worldwide, is usually idiopathic in origin and renal limited. Secondary IgA nephropathy has been associated with systemic disease, including such gastrointestinal tract disturbances as celiac sprue and inflammatory bowel disease. We describe gross hematuria and reversible acute renal failure from IgA nephropathy in a patient with cephalosporin-induced Clostridium difficile colitis. In addition to mesangial IgA and C3 deposition, renal histological examination showed glomerular bleeding, intratubular red blood cell casts, and acute tubular necrosis. To the best of our knowledge, this is the first report of an association between IgA nephropathy and C difficile colitis.

Association of IgA nephropathy with Clostridium difficile colitis

Immunoglobulin A (IgA) nephropathy, the most common cause of glomerulonephritis worldwide, is usually idiopathic in origin and renal limited. Secondary IgA nephropathy has been associated with systemic disease, including such gastrointestinal tract disturbances as celiac sprue and inflammatory bowel disease. We describe gross hematuria and reversible acute renal failure from IgA nephropathy in a patient with cephalosporin-induced Clostridium difficile colitis. In addition to mesangial IgA and C3 deposition, renal histological examination showed glomerular bleeding, intratubular red blood cell casts, and acute tubular necrosis. To the best of our knowledge, this is the first report of an association between IgA nephropathy and C difficile colitis.

A novel human astrocyte cell line (A735) with astrocyte-specific neurotransmitter function

Studies of brain cell function and physiology are hampered by the limited availability of immortal human brain-derived cell lines, as a result of the technical difficulties encountered in establishing immortal human cells in culture. In this study, we demonstrate the application of recombinant DNA vectors expressing SV40 T antigen for the development of immortal human cell cultures, with morphological, growth, and functional properties of astrocytes. Primary human astrocytes were transfected with the SV40 T antigen expression vectors, pSV3neo or p735.6, and cultures were established with an extended lifespan. One of these cultures gave rise to an immortal cell line, designated A735. All the human SV40-derived lines retained morphological features and growth properties of type 1 astrocytes. Immunohistochemical studies and Western blot analysis of the intermediate filament proteins and glutamine synthetase demonstrated a differentiated but immature astrocyte phenotype. Transport of gamma-amino butyric acid and glutamate were examined and found to be by a glial-specific mechanism, consistent with the cell lines' retaining aspects of normal glial function. We conclude that methods based on the use of SV40 T antigen can successfully immortalize human astrocytes, retaining key astrocyte functions, but T antigen-induced proliferation appeared to interfere with expression of glial fibrillary acidic protein. We believe A735 is the first documented nontumor-derived human glial cell line which is immortal.

Application of a rapid method (targeted display) for the identification of differentially expressed mRNAs following NGF-induced neuronal differentiation in PC12 cells

Nerve growth factor (NGF)-induced differentiation of the rat pheochromocytoma, PC12, cell line presents a model system for the study of early gene expression changes involved in neuronal differentiation. Rapid alterations in mRNA expression patterns were investigated in PC12 cells following exposure to NGF using a set of statistically designed primers that exhibit coding-strand bias, and the products were analyzed on agarose gels. This simple and rapid method (targeted display) generated reproducible expression profiles, indicating a complex pattern of gene regulation, and resulted in the identification of a number of NGF-regulated transcripts. Thirty-two of these were selected at random and sequenced, revealing 19 known and 13 novel genes (or ESTs). Northern blot analysis and RT-PCR confirmed the differential regulation of 22 genes (16 known, 6 novel) and demonstrated 1 false positive result. Antisense application of one isolated gene product, the serine/threonine kinase MARK1, prevented neuronal differentiation in transiently transfected PC12 cells.

Current thinking on chronic renal allograft rejection: issues, concerns, and recommendations from a 1997 roundtable discussion

Chronic rejection accounts for most renal allograft losses after the first year posttransplantation. On March 24 and 25, 1997, a roundtable of five transplant surgeons, two nephrologists, and one pathologist assembled in Dallas, Texas, to review critical issues surrounding chronic renal allograft rejection. This article summarizes the presentations and relevant discussions of this meeting regarding the cause of chronic rejection, clinical diagnoses, risk factors, future prospects for intervention strategies, and general recommendations for the transplant community. Growing evidence indicates that chronic rejection is the aggregate sum of irreversible immunologic and nonimmunologic injuries to the renal graft over time. A history of acute rejection episodes and inadequate immunosuppression, likely attributable to inconsistent cyclosporine exposure or poor patient compliance, are among the most recognizable immunologic risk factors for chronic rejection. Donor organ quality, delayed graft function, and other donor and recipient variables leading to reduced nephron mass are nonimmunologic factors that contribute to the progressive deterioration of renal graft function. Clinical management of renal transplant recipients should incorporate both immunologic- and nonimmunologic-based intervention strategies aimed at minimizing risk factors to thwart the progression of chronic rejection and improve long-term allograft and patient survival.

The lymnaea cardioexcitatory peptide (LyCEP) receptor: a G-protein-coupled receptor for a novel member of the RFamide neuropeptide family

A novel G-protein-coupled receptor (GRL106) resembling neuropeptide Y and tachykinin receptors was cloned from the mollusc Lymnaea stagnalis. Application of a peptide extract from the Lymnaea brain to Xenopus oocytes expressing GRL106 activated a calcium-dependent chloride channel. Using this response as a bioassay, we purified the ligand for GRL106, Lymnaea cardioexcitatory peptide (LyCEP), an RFamide-type decapeptide (TPHWRPQGRF-NH2) displaying significant similarity to the Achatina cardioexcitatory peptide (ACEP-1) as well as to the recently identified family of mammalian prolactin-releasing peptides. In the Lymnaea brain, the cells that produce egg-laying hormone are the predominant site of GRL106 gene expression and appear to be innervated by LyCEP-containing fibers. Indeed, LyCEP application transiently hyperpolarizes isolated egg-laying hormone cells. In the Lymnaea pericardium, LyCEP-containing fibers end blindly at the pericardial lumen, and the heart is stimulated by LyCEP in vitro. These data confirm that LyCEP is an RFamide ligand for GRL106.

Molecular cloning and characterization of an invertebrate homologue of a neuropeptide Y receptor

Neuropeptide Y is an abundant and physiologically important peptide in vertebrates having effects on food intake, sexual behaviour, blood pressure and circadian rhythms. Neuropeptide Y homologues have been found in invertebrates, where they are very likely to play similar, important roles. Although five neuropeptide Y-receptor subtypes have been identified in mammals, none has been reported from invertebrates. Here we describe the cloning of a neuropeptide Y-receptor from the brain of the snail Lymnaea stagnalis. The identity of the receptor was deduced by expressing the neuropeptide Y-receptor-encoding cDNA in Chinese Hamster Ovary cells, which were subsequently challenged with size-fractionated Lymnaea brain extracts. An active peptide, selected on the basis of its ability to induce changes in cAMP levels, was purified to homogeneity, analysed by mass spectrometry and amino acid sequence determination, and turned out to be a Lymnaea homologue of neuropeptide Y.

Maximal parenteral glucose oxidation in hypermetabolic young children: a stable isotope study

BACKGROUND

During periods in which nutrition support of critically ill young children must be parenteral, glucose infusions are administered at up to 10 or more mg.kg-1.min-1 to meet predicted energy needs. However, data in adults suggest that such high glucose loads exceed the ability to oxidize glucose in the hormonal milieu that characterizes critical illness. The purpose of this study was to determine if these high glucose loads are oxidized by critically ill young children.

METHODS

Ten young children with serious burns were enrolled in a stable isotope study of glucose metabolism. These five boys and five girls were an average age of 5.2 years (range, 1 to 11 years), weight of 18.4 kg (range, 10 to 31 kg) and burn size of 51.6% of the body surface (range, 35% to 86%). During clinically required episodes of parenteral nutrition support, we used the [13C6]glucose tracer to assess the efficacy of glucose oxidation at both 5 and 8 mg.kg-1.min-1. Serum glucose was recorded and indirect calorimetry was performed.

RESULTS

The fraction of exogenous glucose oxidation fell from 59% +/- 5% to 47% +/- 5% (p < .05). Although there was a significantly increased level of total glucose oxidation (3.2 to 3.8 mg.kg-1.min-1), this increment (29% +/- 9%) was accompanied by a significant decrease in the efficiency of energy production, because the bulk of the additional glucose above 5 mg.kg-1.min-1 was not being oxidized. Plasma glucose concentration did not change (145 +/- 4 vs 137 +/- 4 mg/dL, p < .01) and whole-body expired gas respiratory quotients remained consistent with a mixed fuel oxidation, implying that there exists an increased rate of exogenous glucose uptake by tissues in nonoxidative pathways.

CONCLUSIONS

Maximum glucose oxidation in severely burned children occurs at intakes approximating 5 mg.kg-1.min-1. Exogenous glucose in excess of this amount enters nonoxidative pathways and is unlikely to improve energy balance. Clinical markers such as serum glucose levels or expired respiratory quotient may not detect inefficient glucose utilization.

Both C3a and C3a(desArg) regulate interleukin-6 synthesis in human peripheral blood mononuclear cells

Synthesis of complement components is part of the acute-phase response. Interleukin-6 (IL-6) is a critical mediator of the acute-phase response during infections and injuries. Plasma levels of C3a and IL-6 have been proposed as prognostic indicators in sepsis and trauma. The effects of C3a and C3a(des)Arg on IL-6 gene expression and protein production in human peripheral blood mononuclear cells (PBMC) were investigated. Neither C3a nor C3a(des)Arg alone induced detectable IL-6 protein or mRNA levels. However, C3a and C3a(des)Arg affected endotoxin-induced IL-6 synthesis in a dose-dependent manner. In nonadherent PBMC, C3a or C3a(des)Arg suppressed, while in adherent PBMC, C3a or C3a(des)Arg enhanced IL-6 protein and mRNA levels. These results suggest that C3a and C3a(des)Arg may provide a control mechanism of acute-phase responses by enhancing IL-6 synthesis in adherent monocytes at local inflammatory sites and by inhibiting IL-6 synthesis in circulating monocytes.

Neural modulation of gut motility by myomodulin peptides and acetylcholine in the snail Lymnaea

Families of peptide neuromodulators are believed to play important roles in neural networks that control behaviors. Here, we investigate the expression and role of one such group of modulators, the myomodulins, in the feeding system of Lymnaea stagnalis. Using a combination of in situ hybridization and antibody staining, expression of the myomodulin gene was confirmed in a number of identified behaviorally significant neuronal types, including the paired B2 motor neurons. The B2 cells were shown to project axons to the proesophagus, where they modulate foregut contractile activity. The presence of the five myomodulin peptide structures was confirmed in the B2 cells, the proesophagus, and the intervening nerve by mass spectrometry. Using a sensitive cell culture assay, evidence that the B2 cells are cholinergic also is presented. Application of four of the five myomodulin peptides to the isolated foregut increased both contraction frequency and tonus, whereas the main effect of acetylcholine (ACh) application was a large tonal contraction. The fifth myomodulin peptide (pQIPMLRLamide) appeared to have little or no effect on gut motility. Coapplication of all five myomodulin peptides gave a greater increase in tonus than that produced by the peptides applied individually, suggesting that corelease of the peptides onto the gut would produce an enhanced response. The combined effects that the myomodulin peptides and ACh have on foregut motility can mimic the main actions of B2 cell stimulation.