RDP: detection of recombination amongst aligned sequences

SUMMARY

Recombination Detection Program (RDP) is a program that applies a pairwise scanning approach to the detection of recombination amongst a group of aligned DNA sequences. The software runs under Windows95 and combines highly automated screening of large numbers of sequences with a highly interactive interface for examining the results of the analyses.

Functional recovery in parkinsonian monkeys treated with GDNF

Parkinson's disease results from the progressive degeneration of dopamine neurons that innervate the striatum. In rodents, glial-cell-line-derived neurotrophic factor (GDNF) stimulates an increase in midbrain dopamine levels, protects dopamine neurons from some neurotoxins, and maintains injured dopamine neurons. Here we extend the rodent studies to an animal closer to the human in brain organization and function, by evaluating the effects of GDNF injected intracerebrally in rhesus monkeys that have had the symptomatology and pathophysiological features of Parkinson's disease induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The recipients of GDNF displayed significant improvements in three of the cardinal symptoms of parkinsonism: bradykinesia, rigidity and postural instability. GDNF administered every four weeks maintained functional recovery. On the lesioned side of GDNF-treated animals, dopamine levels in the midbrain and globus pallidus were twice as high, and nigral dopamine neurons were, on average, 20% larger, with an increased fibre density. The results indicate that GDNF may be of benefit in the treatment of Parkinson's disease.

Changes in plasma HIV-1 RNA and CD4+ lymphocyte counts and the risk of progression to AIDS. Veterans Affairs Cooperative Study Group on AIDS

BACKGROUND

Clinical trials of antiretroviral drugs can take years to complete because the outcomes measured are progression to the acquired immunodeficiency syndrome (AIDS) or death. Trials could be accelerated by the use of end points such as changes in CD4+ lymphocyte counts and plasma levels of human immunodeficiency virus type 1 (HIV-1) RNA and beta 2-microglobulin, but there is uncertainty about whether these surrogate measures are valid predictors of disease progression.

METHODS

We analyzed data from the Veterans Affairs Cooperative Study on AIDS, which compared immediate with deferred zidovudine therapy. Patients' plasma levels of HIV-1 RNA and beta 2-microglobulin were measured in stored plasma.

RESULTS

Among the 129 patients in the immediate-treatment group, 34 had disease that progressed to AIDS, as compared with 57 of the 141 patients in the deferred-treatment group (P = 0.03). Progression to AIDS correlated strongly with base-line CD4+ lymphocyte counts (P = 0.001) and plasma levels of HIV-1 RNA (P < 0.001), but not with base-line levels of beta 2-microglobulin (P = 0.14). A decrease of at least 75 percent in the plasma level of HIV-1 RNA over the first six months of zidovudine therapy accounted for 59 percent of the benefit of treatment, defined as the absence of progression to AIDS (95 percent confidence interval, 13 to 112 percent). Plasma beta 2-microglobulin levels and CD4+ lymphocyte counts explained less of the effect of treatment. A 75 percent decrease in the plasma HIV-1 RNA level plus a 10 percent increase in the CD4+ lymphocyte count could explain 79 percent of the treatment effect (95 percent confidence interval, 27 to 145 percent).

CONCLUSIONS

Treatment-induced changes in the plasma HIV-1 RNA level and the CD4+ lymphocyte count, taken together, are valid predictors of the clinical progression of HIV-related disease and can be used to assess the efficacy of zidovudine and possibly other antiretroviral drugs as well.

Risk factors for complications of chronic anticoagulation. A multicenter study. Warfarin Optimized Outpatient Follow-up Study Group

OBJECTIVE

To define risk factors for complications that occur during warfarin therapy.

DESIGN

Retrospective cohort study.

SETTING

Five anticoagulation clinics.

PATIENTS

Nine hundred twenty-eight consecutive patients receiving 1103 courses of warfarin.

MAIN OUTCOME MEASURES

Hemorrhagic and thromboembolic complications.

RESULTS

In 1950 patient-years of follow-up, there were 1332 bleeding events (4 were classified as fatal, 31 as life-threatening, 226 as serious, and 1071 as minor). The cumulative incidence of fatal bleeding was 1% at 1 year and 2% at 3 years. The cumulative incidences of first episodes of life-threatening and serious bleeding at 1, 2, 4, and 8 years were 1%, 2%, 5%, and 9% and 12%, 20%, 28%, and 40%, respectively. Of 156 patients who had a serious or life-threatening hemorrhage, 32% suffered a recurrence, typically within 1 year. Independent predictors of a first episode of serious bleeding included a mean prothrombin time ratio (PTR) of 2.0 or more during the course of treatment (relative risk, 3.0; 95% CI, 1.9 to 4.7); recent initiation of warfarin therapy (relative risk during the first 3 months compared with the rest of the first year, the second year, and anytime thereafter, 1.9 [CI, 1.3 to 3.0], 3.0 [CI, 1.8 to 4.8], and 5.9 [CI, 3.8 to 9.3], respectively); variability of the PTR over time (relative risk for the highest compared with the lowest tertile, 1.6 [CI, 1.2 to 2.7]); and the presence of 3 or more comorbid conditions (RR, 1.4 [CI, 1.1 to 2.5]). Age, reason for anticoagulation, use of interfering drugs, and hypertension were not associated with risk for bleeding. The risk for a thromboembolic complication at a PTR of less than 1.3 was 3.6 (CI, 2.1 to 6.4) times higher than at a PTR of 1.3 to 1.5.

CONCLUSIONS

The incidence of warfarin-associated bleeding may be reduced by attending to modifiable risk factors (that is, highly variable PTRs and values greater than 2.0), frequent monitoring early in treatment, and careful patient selection. Older age, in and of itself, is not a risk factor.

Comorbidity in ADHD: implications for research, practice, and DSM-V

OBJECTIVE

Since the introduction of DSM-III/III-R, clinicians and investigators have shown increasing interest in the study of conditions comorbid with attention-deficit hyperactivity disorder (ADHD). Better understanding ADHD comorbidity patterns is needed to guide treatment, research and future classification approaches.

METHOD

The ADHD literature from the past 15 years was reviewed to (1) explore the most prevalent patterns of ADHD comorbidity; (2) examine the correlates and longitudinal predictors of comorbidity; and (3) determine the extent to which comorbid patterns convey unique information concerning ADHD etiology, treatment and outcomes. To identify potential new syndromes, the authors examined comorbid patterns based on eight validational criteria.

RESULTS

The largest available body of literature concerned the comorbidity with ADHD and conduct disorder/aggression, with a substantially smaller amount of data concerning other comorbid conditions. In many areas the literature was sparse, and pertinent questions concerning comorbidity patterns remain unexplored. Nonetheless available data warrant the delineation of two new subclassifications of ADHD: (1) ADHD aggressive subtype, and (2) ADHD, anxious subtype.

CONCLUSIONS

Additional studies of the frequency of comorbidity and associated factors are greatly needed to include studies of differential effects of treatment of children with various comorbid ADHD disorders, as well as of ADHD children who differ on etiological factors.

Characterization of cytokine-induced hyperalgesia

Agents which induce symptoms of illness, such as lipopolysaccharide (LPS), cause diverse effects including hyperalgesia. While previous studies have examined central pathways mediating LPS hyperalgesia, the initial steps in activating this system remain unknown. Since LPS induces the release of various cytokines and eicosinoids from immune cells, the present series of experiments examined the potential involvement of these substances in LPS hyperalgesia. This work demonstrates that: (a) Interleukin-1 beta (IL-1 beta) can produce hyperalgesia following either intraperitoneal or intracerebroventricular injection. In contrast, IL-1 beta delivered intrathecally did not affect pain responsivity. (b) Liver macrophages (Kupffer cells) appear to be critically involved, and relay signals to the brain via hepatic vagal afferents. (c) Both IL-1 beta and tumor necrosis factor appear to be critical mediators of LPS hyperalgesia. In contrast, prostaglandins do not appear to be involved. Taken together, these studies suggest that substances classically thought of as products of the immune system may dynamically enhance pain responsivity via actions either on the hepatic vagus or at central sites.

Blockade of interleukin-1 induced hyperthermia by subdiaphragmatic vagotomy: evidence for vagal mediation of immune-brain communication

Interleukin-1 beta (IL-1 beta), a cytokine released by activated immune cells, elicits various illness symptoms including hyperthermia. Previous hypotheses to account for these actions have focused on blood-borne IL-1 beta exerting its effects directly at the level of the brain. However, recent behavioral and physiological evidence suggest that IL-1 beta can activate the subdiaphragmatic vagus. The present experiments demonstrate that subdiaphragmatic vagal transection disrupts the hyperthermia-inducing effects of recombinant human IL-1 beta and stress. These data provide evidence for a novel route of immune-brain communication, as well as a novel route whereby stress can influence physiological processes.

Glial cell line-derived neurotrophic factor reverses toxin-induced injury to midbrain dopaminergic neurons in vivo

Fischer 344 rats were unilaterally injected into the medial forebrain bundle with 6-hydroxydopamine (6-OHDA). Apomorphine-induced rotational behavior was used to select animals whose rotation exceeded 300 turns/h, corresponding to greater than 95% dopamine (DA) depletion in the ipsilateral striatum. Four weeks later, glial cell line-derived neurotrophic factor (GDNF) or vehicle was injected intranigrally ipsilateral to the lesion (0.1-100 micrograms). The highest dose of GDNF tested produced a marked decrease in rotational behavior. This dose also produced levels of DA in the ipsilateral substantia nigra (SN) which were not statistically different from the contralateral side. Vehicle-treated animals showed a marked DA depletion in the ipsilateral SN. These results demonstrate neurochemical and behavioral improvements in unilaterally DA-lesioned rats following intranigral administration of GDNF, suggesting that GDNF may develop into a useful therapy for Parkinson's disease.

Guidelines on the management of common bile duct stones (CBDS)

The last 30 years have seen major developments in the management of gallstone-related disease, which in the United States alone costs over 6 billion dollars per annum to treat. Endoscopic retrograde cholangiopancreatography (ERCP) has become a widely available and routine procedure, whilst open cholecystectomy has largely been replaced by a laparoscopic approach, which may or may not include laparoscopic exploration of the common bile duct (LCBDE). In addition, new imaging techniques such as magnetic resonance cholangiography (MR) and endoscopic ultrasound (EUS) offer the opportunity to accurately visualise the biliary system without instrumentation of the ducts. As a consequence clinicians are now faced with a number of potentially valid options for managing patients with suspected CBDS. It is with this in mind that the following guidelines have been written.

Evidence for the involvement of spinal cord glia in subcutaneous formalin induced hyperalgesia in the rat

Subcutaneous (s.c.) injection of formalin induces a rapid and prolonged hyperalgesia across widespread areas of the body. This hyperalgesic state involves a brain-to-spinal cord pathway, likely arising from the nucleus raphe magnus. The present study examined whether subsequent activation of spinal cord glia may be critical for the hyperalgesic state to be observed in rats. Glia were considered candidates as they can, upon activation, release a variety of substances known to be critical for the mediation of subcutaneous formalin-induced hyperalgesia including glutamate, aspartate, nitric oxide, arachidonic acid and cyclooxygenase products such as prostaglandins. This series of experiments demonstrate that formalin-induced hyperalgesia in rats can be blocked by intrathecal administration of agents that: (a) disrupt glial function (using either 1 nmol fluorocitrate which is a glial metabolic inhibitor, or 9 microg CNI-1493 which disrupts synthesis of nitric oxide and cytokines in monocyte-derived cells; ANOVA revealed reliable group effects for each drug with P < 0.0005); or (b) disrupt the action of glial products (using 10, 50, or 100 microg of a human recombinant interleukin-1 receptor antagonist or 10 microl antibody directed against nerve growth factor; ANOVA revealed reliable group effects for each drug with P < 0.001). Disruption appeared to be selective, as blockade of only select glial products was effective. That is, up to 120 microg of a functional antagonist of tumor necrosis factor-alpha (TNF binding protein) and 5 microl of an antibody against complement-3 produced no statistically reliable reduction in formalin-induced hyperalgesia. Taken together, the present series of experiments suggest an important role for spinal glial cells in the cascade of events that are initiated by descending signals following s.c. administration of formalin.

Intrathecal interleukin-1 receptor antagonist in combination with soluble tumor necrosis factor receptor exhibits an anti-allodynic action in a rat model of neuropathic pain

The expression of interleukin-1beta and tumor necrosis factor has previously been shown to be up-regulated in the spinal cord of several rat mononeuropathy models. This present study was undertaken to determine whether blocking the action of central interleukin-1beta and tumor necrosis factor attenuates mechanical allodynia in a gender-specific manner in a rodent L5 spinal nerve transection model of neuropathic pain, and whether this inhibition occurs via down-regulation of the central cytokine cascade or blockade of glial activation. Interleukin-1 receptor antagonist or soluble tumor necrosis factor receptor was administered intrathecally via lumbar puncture to male Holtzman rats in a preventative pain strategy, in which therapy was initiated 1h prior to surgery. Administration of soluble tumor necrosis factor receptor attenuated mechanical allodynia, while interleukin-1 receptor antagonist alone was unable to decrease allodynia. Interleukin-1 receptor antagonist in combination with soluble tumor necrosis factor receptor, administered to both male and female rats in a preventative pain strategy, significantly reduced mechanical allodynia in a dose-dependent manner (P<0.01). The magnitude of attenuation in allodynia was similar in both males and females. Immunohistochemistry on L5 spinal cord revealed similar astrocytic and microglial activation regardless of treatment. At days 3 and 7 post-transection, animals receiving daily interleukin-1 receptor antagonist in combination with soluble tumor necrosis factor receptor exhibited significantly less interleukin-6, but not interleukin-1beta, in the L5 spinal cord compared to vehicle-treated animals. In an existing pain paradigm, in which treatment was initiated on day 7 post-transection, interleukin-1 receptor antagonist in combination with soluble tumor necrosis factor receptor attenuated mechanical allodynia (P<0.05) in male rats. These findings further support a role for central interleukin-1beta and tumor necrosis factor in the development and maintenance of neuropathic pain through induction of a proinflammatory cytokine cascade.

Risk factors for complication following ERCP; results of a large-scale, prospective multicenter study

BACKGROUND AND STUDY AIMS

Analyses of endoscopic retrograde cholangiopancreatography (ERCP) complication are often constrained by the number of endpoints observed. This large-scale study aimed to identify the principal risk factors for ERCP complication.

PATIENTS AND METHODS

This was a prospective multicenter study of ERCP complications, based in five English regions. An exploratory univariable analysis of patients' first recorded procedures identified potentially important patient- and procedure-related factors. For overall complications and pancreatitis, variables significant in univariable analysis were included in multiple regression.

RESULTS

A total of 66 centers collected data on 5264 ERCPs, performed on 4561 patients. A therapeutic intervention was attempted in 3447/4561 (76%) of patients as part of their first recorded ERCP. Following first recorded ERCP, 230 patients (5.0%) suffered > or = 1 complication: pancreatitis in 74 (1.6%), cholangitis in 48 (1.0 %), hemorrhage in 40 (0.9%), perforation in 20 (0.4%), and miscellaneous in 54 (1.2%). Significant factors from multiple regression were included in a multi-level analysis, which incorporated variables measured at the level of the endoscopist and hospital. For overall complication, risk factors ( P value, odds ratio [OR], 95% confidence interval [CI]) were: cannulation attempts > 1 ( P = 0.094, OR 1.32, 95% CI 0.95-1.83), precut ( P = 0.033, OR 1.55, 95 % CI 1.04-2.32), and suspected sphincter of Oddi dysfunction ( P = 0.121, OR 1.97, 95 % CI 0.84-4.64). For pancreatitis, risk factors ( Pvalue, OR, and 95 % CI) were: cannulation attempts > 1 ( P = 0.0001, OR 3.14, 95% CI 1.74-5.67), female sex ( P < 0.001, OR 2.22, 95% CI 1.43-3.45), age ( P < 0.002, OR 1.09 per 5 year decrease, 95% CI 1.03-1.15), and performance in a district (as opposed to university) hospital ( P = 0.034, OR 2.41, 95% CI 1.08-5.41).

CONCLUSION

Careful patient selection combined with skilled cannulation minimizes complications. Higher-risk procedures should be performed in specialist centers.

Clinical intestinal transplantation: a decade of experience at a single center

OBJECTIVE

To assess the long-term efficacy of intestinal transplantation under tacrolimus-based immunosuppression and the therapeutic benefit of newly developed adjunct immunosuppressants and management strategies.

SUMMARY BACKGROUND DATA

With the advent of tacrolimus in 1990, transplantation of the intestine began to emerge as therapy for intestinal failure. However, a high risk of rejection, with the consequent need for acute and chronic high-dose immunosuppression, has inhibited its widespread application.

METHODS

During an 11-year period, divided into two segments by a 1-year moratorium in 1994, 155 patients received 165 intestinal allografts under immunosuppression based on tacrolimus and prednisone: 65 intestine alone, 75 liver and intestine, and 25 multivisceral. For the transplantations since the moratorium (n = 99), an adjunct immunosuppressant (cyclophosphamide or daclizumab) was used for 74 transplantations, adjunct donor bone marrow was given in 39, and the intestine of 11 allografts was irradiated with a single dose of 750 cGy.

RESULTS

The actuarial survival rate for the total population was 75% at 1 year, 54% at 5 years, and 42% at 10 years. Recipients of liver plus intestine had the best long-term prognosis and the lowest risk of graft loss from rejection (P =.001). Since 1994, survival rates have improved. Techniques for early detection of Epstein-Barr and cytomegaloviral infections, bone marrow augmentation, the adjunct use of the interleukin-2 antagonist daclizumab, and most recently allograft irradiation may have contributed to the better results.

CONCLUSION

The survival rates after intestinal transplantation have cumulatively improved during the past decade. With the management strategies currently under evaluation, intestinal transplant procedures have the potential to become the standard of care for patients with end-stage intestinal failure.

Lipopolysaccharide pre-treatment induces resistance against subsequent focal cerebral ischemic damage in spontaneously hypertensive rats

Ischemic tolerance was induced in spontaneously hypertensive rats (SHR) by injection of a single dose of lipopolysaccharide (LPS) (0.9 mg/kg, i.v.) 1-7 days prior to permanent middle cerebral artery occlusion (MCAO). Infarct volume, evaluated 24 h after MCAO, was significantly reduced by LPS administration 2, 3 or 4 days prior to MCAO (22.8, 25.9 and 20.5%, respectively). The beneficial effect of LPS pre-treatment was completely nullified by concurrent administration of TNFbp. On this basis, the tolerance to ischemia induced by LPS is likely to be mediated by TNF-alpha.

Fundamental properties of local anesthetics. II. Measured octanol:buffer partition coefficients and pKa values of clinically used drugs

Because local anesthetic molecules interact with ion channel proteins embedded in membranes to effect impulse blockade, and because their clinical potency often depends on both vascular absorption and distribution into the tissue surrounding the site of deposition, the ability to partition into these various compartments is an important determinant of local anesthetic action. Therefore, the hydrophobic nature of local anesthetics used clinically was characterized by the octanol:buffer partition coefficients of their charged (P+) and neutral (Po) species. This was accomplished by previously described optical methods in which direct spectrophotometric measurement of both the pH-dependent distribution coefficient (Q) and of the ionization permit calculation of the pKa and partition coefficients. The rates of alkaline hydrolysis of ester-linked molecules also were measured to assess potential interference of such hydrolysis with the physicochemical assays. Results indicate that the hydrophobicity of a local anesthetic is increased by manipulation of the molecular structure at three sites: (a) the aromatic ring; (b) the intermediate linking group; and (c) the tertiary amine. Po for the agents studied was 10(3)-10(5) times greater than P+. Although there is no systematic relationship between hydrophobicity and pKa, the latter is greater with ester-linked (pKa = 8.59-9.30) than with amide-linked (pKa = 7.92-8.21) local anesthetics. All of the charged species, with the exception of bupivacaine, selectively partition into the aqueous environment (P+ less than 1.0). The temperature dependence of partitioning of the local anesthetics, measured at 25 and 36 degrees C, indicates an entropy-driven hydrophobic uptake. Solutions buffered with bicarbonate and including 5% CO2 showed the same local anesthetic partitioning as that of CO2-free solutions, suggesting that potentiation of impulse blockade by CO2 is not due to increased membrane uptake. Correlations of physicochemical properties of local anesthetics with potencies on isolated nerve confirm that the more potent local anesthetics have greater octanol:buffer partition coefficients, and that the ester-linked local anesthetics are more potent than their amide-linked counterparts having the same hydrophobicities. The correlations of structure with potency also suggest that the extracellular protonated species may contribute to impulse blockade.

Thermal hyperalgesia and mechanical allodynia produced by intrathecal administration of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein, gp120

Astrocytes and microglia in the spinal cord have recently been reported to contribute to the development of peripheral inflammation-induced exaggerated pain states. Both lowering of thermal pain threshold (thermal hyperalgesia) and lowering of response threshold to light tactile stimuli (mechanical allodynia) have been reported. The notion that spinal cord glia are potential mediators of such effects is based on the disruption of these exaggerated pain states by drugs thought to preferentially affect glial function. Activation of astrocytes and microglia can release many of the same substances that are known to mediate thermal hyperalgesia and mechanical allodynia. The aim of the present series of studies was to determine whether exaggerated pain states could also be created in rats by direct, intraspinal immune activation of astrocytes and microglia. The immune stimulus used was peri-spinal (intrathecal, i.t.) application of the Human Immunodeficiency Virus type 1 (HIV-1) envelope glycoprotein, gp120. This portion of HIV-1 is known to bind to and activate microglia and astrocytes. Robust thermal hyperalgesia (tail-flick, TF, and Hargreaves tests) and mechanical allodynia (von Frey and touch-evoked agitation tests) were observed in response to i.t. gp120. Heat denaturing of the complex protein structure of gp120 blocked gp120-induced thermal hyperalgesia. Lastly, both thermal hyperalgesia and mechanical allodynia to i.t. gp120 were blocked by spinal pretreatment with drugs (fluorocitrate and CNI-1493) thought to preferentially disrupt glial function.

Tumor escape from immune recognition: lethal recurrent melanoma in a patient associated with downregulation of the peptide transporter protein TAP-1 and loss of expression of the immunodominant MART-1/Melan-A antigen

In the last few years, mutiple protein target antigens for immunorecognition by T cells have been identified on human melanoma. How melanoma lesions escape from functional antigen-specific immune recognition remains poorly understood. We have identified the concomitant loss of the immunodominant T cell-defined MART-1/Melan-A antigen and downregulation of the TAP-1 gene in a recurrent metastatic melanoma that was resected in 1993. This phenotype was not observed for an earlier autologous melanoma lesion resected in 1987. The "antigen loss" could be restored in the variant tumor cell line by simultaneously providing both the MART-1/Melan-A gene (by retroviral transfer) and the TAP-1 gene (by a bioballistic approach) resulting in tumor cell sensitivity to MART-1/Melan-A-specific cytotoxic T lymphocytes. This suggests that tumor escape from immune surveillance may have occurred in vivo as a sequential result of (a) antigen loss, and (b) downregulation of the peptide-transporter protein TAP-1 expression by this patient's tumor over a 6-yr period from 1987 to 1993. These results suggest that the characterization of the T cell response to melanoma in individual patients and definition of the immunologically relevant genetic defects in tumors may be required to select the most effective therapeutic strategies for a given patient.

Recognition and management of fatty acid oxidation defects: a series of 107 patients

In a personal series of 107 patients, we describe clinical presentations, methods of recognition and therapeutic management of inherited fatty acid oxidation (FAO) defects. As a whole, FAO disorders appear very severe: among the 107 patients, only 57 are still living. Including 47 siblings who died early in infancy, in total 97 patients died, of whom 30% died within the first week of life and 69% before 1 year. Twenty-eight patients presented in the neonatal period with sudden death, heart beat disorders, or neurological distress with various metabolic disturbances. Hepatic presentations were observed in 73% of patients (steatosis, hypoketotic hypoglycaemia, hepatomegaly, Reye syndrome). True hepatic failure was rare (10%); cholestasis was observed in one patient with LCHAD deficiency. Cardiac presentations were observed in 51% of patients: 67% patients presented with cardiomyopathy, mostly hypertrophic, and 47% of patients had heart beat disorders with various conduction abnormalities and arrhythmias responsible for collapse, near-miss and sudden unexpected death. All enzymatic blocks affecting FAO except CPT I and MCAD were found associated with cardiac signs. Muscular signs were observed in 51% of patients (of whom 64% had myalgias or paroxysmal myoglobinuria, and 29% had progressive proximal myopathy). Chronic neurologic presentation was rare, except in LCHAD deficiency (retinitis pigmentosa and peripheral neuropathy). Renal presentation (tubulopathy) and transient renal failure were observed in 27% of patients. The diagnosis of FAO disorders is generally based on the plasma acylcarnitine profile determined by FAB-MS/MS from simple blood spots collected on a Guthrie card. Urinary organic acid profile and total and free plasma carnitine can also be very helpful, mostly in acute attacks. If there is no significant disturbance between attacks, the diagnosis is based upon a long-chain fatty acid loading test, fasting test, and in vitro studies of fatty acid oxidation on fresh lymphocytes or cultured fibroblasts. Treatment includes avoiding fasting or catabolism, suppressing lipolysis, and carnitine supplementation. The long-term dietary therapy aims to prevent periods of fasting and restrict long-chain fatty acid intake with supplementation of medium-chain triglycerides. Despite these therapeutic measures, the long-term prognosis remains uncertain.

Surveillance for recurrent head and neck cancer using positron emission tomography

PURPOSE

Earlier detection of head and neck cancer recurrence may improve survival. We evaluated the ability of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) to detect recurrence in a prospective trial using sequential PET scans.

PATIENTS AND METHODS

Serial posttherapy FDG-PET was prospectively performed in 44 patients with stage III or IV head and neck cancer. PET was performed twice during the first posttreatment year (at 2 and 10 months after therapy) and thereafter as needed. After therapy, patients were grouped, based on tissue biopsies, into those who achieved a complete response (CR) and those who had residual disease (RD). Patients who achieved a CR were further grouped into those without evidence of disease and those who had recurrence by 1 year after completion of therapy. Disease status as determined by physical examination (PE), PET, and correlative imaging was compared.

RESULTS

Eight patients were lost to follow-up and six had RD after therapy. Of the remaining 30 patients with a CR, 16 had recurrence in the first year after therapy. Five of these 16 patients had recurrence detected by PET only, four by PET and correlative imaging only, five by PE and PET only, and two by PE, correlative imaging, and PET. Only PET detected all recurrences in the first year. PET performed better than correlative imaging (P =.013) or PE (P =.002) in the detection of recurrence.

CONCLUSION

PET can detect head and neck tumor recurrence when it may be undetectable by other clinical methods. FDG-PET permits highly accurate detection of head and neck cancer recurrence in the posttherapy period.

The neuroprotective agent riluzole inhibits release of glutamate and aspartate from slices of hippocampal area CA1

Riluzole is believed to exert its anticonvulsant and neuroprotective actions by reducing glutamate release. This study demonstrated that 10-30 microM riluzole reduces the K(+)-evoked release of glutamate and aspartate from slices of hippocampal area CA1. Only higher concentrations reduced gamma-aminobutyrate (GABA) release. These actions of riluzole were not occluded by tetrodotoxin. Riluzole did not diminish the ability of glutamate analogues to depolarize CA1 pyramidal cells, as determined from grease-gap recordings. Therefore the anticonvulsant and neuroprotective actions of riluzole in the hippocampus may be at least partly explained by its ability to inhibit glutamate/aspartate release from synaptic terminals.

Arrhythmias and conduction defects as presenting symptoms of fatty acid oxidation disorders in children

BACKGROUND

The clinical manifestations of inherited disorders of fatty acid oxidation vary according to the enzymatic defect. They may present as isolated cardiomyopathy, sudden death, progressive skeletal myopathy, or hepatic failure. Arrhythmia is an unusual presenting symptom of fatty acid oxidation deficiencies.

METHODS AND RESULTS

Over a period of 25 years, 107 patients were diagnosed with an inherited fatty acid oxidation disorder. Arrhythmia was the predominant presenting symptom in 24 cases. These 24 cases included 15 ventricular tachycardias, 4 atrial tachycardias, 4 sinus node dysfunctions with episodes of atrial tachycardia, 6 atrioventricular blocks, and 4 left bundle-branch blocks in newborn infants. Conduction disorders and atrial tachycardias were observed in patients with defects of long-chain fatty acid transport across the inner mitochondrial membrane (carnitine palmitoyl transferase type II deficiency and carnitine acylcarnitine translocase deficiency) and in patients with trifunctional protein deficiency. Ventricular tachycardias were observed in patients with any type of fatty acid oxidation deficiency. Arrhythmias were absent in patients with primary carnitine carrier, carnitine palmitoyl transferase I, and medium chain acyl coenzyme A dehydrogenase deficiencies.

CONCLUSIONS

The accumulation of arrhythmogenic intermediary metabolites of fatty acids, such as long-chain acylcarnitines, may be responsible for arrhythmias. Inborn errors of fatty acid oxidation should be considered in unexplained sudden death or near-miss in infants and in infants with conduction defects or ventricular tachycardia. Diagnosis can be easily ascertained by an acylcarnitine profile from blood spots on filter paper.

Osteogenic protein-1 prevents renal fibrogenesis associated with ureteral obstruction

Unilateral ureteral obstruction (UUO) is a model of renal injury characterized by progressive tubulointerstitial fibrosis and renal damage, while relatively sparing the glomerulus and not producing hypertension or abnormalities in lipid metabolism. Tubulointerstitial fibrosis is a major component of several kidney diseases associated with the progression to end-stage renal failure. Here we report that when a critical renal developmental morphogen, osteogenic protein-1 (OP-1; 100 or 300 microg/kg body wt), is administered at the time of UUO and every other day thereafter, interstitial inflammation and fibrogenesis are prevented, leading to preservation of renal function during the first 5 days after obstruction. Compared with angiotensin-converting enzyme inhibition with enalapril treatment, OP-1 was more effective in preventing tubulointerstitial fibrosis and in preserving renal function. The mechanism of OP-1- induced renal protection was associated with prevention of tubular atrophy, an effect not shared with enalapril, and was related to preservation of tubular epithelial integrity. OP-1 blocked the stimulation of epithelial cell apoptosis produced by UUO, which promoted maintenance of tubular epithelial integrity. OP-1 preserved renal blood flow (RBF) during UUO, but enalapril also stimulated RBF. Thus OP-1 treatment inhibited tubular epithelial disruption stimulated by the renal injury of UUO, preventing tubular atrophy and diminishing the activation of tubulointerstitial inflammation and fibrosis and preserving renal function.