Loss of function mutations in the gene encoding Omi/HtrA2 in Parkinson's disease

Recently targeted disruption of Omi/HtrA2 has been found to cause neurodegeneration and a parkinsonian phenotype in mice. Using a candidate gene approach, we performed a mutation screening of the Omi/HtrA2 gene in German Parkinson's disease (PD) patients. In four patients, we identified a novel heterozygous G399S mutation, which was absent in healthy controls. Moreover, we identified a novel A141S polymorphism that was associated with PD (P<0.05). Both mutations resulted in defective activation of the protease activity of Omi/HtrA2. Immunohistochemistry and functional analysis in stably transfected cells revealed that S399 mutant Omi/HtrA2 and to a lesser extent, the risk allele of the A141S polymorphism induced mitochondrial dysfunction associated with altered mitochondrial morphology. Cells overexpressing S399 mutant Omi/HtrA2 were more susceptible to stress-induced cell death than wild-type. On the basis of functional genomics, our results provide a novel link between mitochondrial dysfunction and neurodegeneration in PD.     

Phase I study using desferrioxamine and iron sorbitol citrate in an attempt to modulate the iron status of tumor cells to enhance doxorubicin activity

Summary a novel approach to enhance the activity of doxorubicin is to increase the availability of cellular chelatable iron to participate in doxorubicin-mediated free-radical generation. To achieve this, we designed a regimen consisting of desferrioxamine (DFO, 50 mg/kg daily given as an i. v. infusion over 72 h) to increase cellular iron uptake. Thereafter, the combination of iron sorbitol citrate (ISC) and doxorubicin (as a single agent or as part of the CHOP regimen) was given. In a phase I study we investigated the toxicity of this regimen in nine patients with refractory malignant disease. Severe but reversible ocular toxicity (i. e., acute maculopathy) was observed in two patients. As these patients were the only ones who were pretreated with cisplatin, we caution against the use of DFO in cisplatin-pretreated patients. Severe phlebitis was encountered in five of nine patients. A partial remission was observed in two of four patients with refractory Non-Hodgkin's lymphoma who were treated with DFO, ISC, and doxorubicin as part of the CHOP regimen. We conclude that pretreatment with DFO and iron sorbitol citrate may be of benefit in the treatment of malignancies with doxorubicin-containing regimens, but ocular toxicity and severe phlebitis limits the use of DFO in this approach. The attachment of DFO to biocompatible polymers may be a method of overcoming the observed toxicity and warrants further study.Abbreviations PR partial remission - PD progressive disease - OT ocular toxicity - Phl phlebitis of WHO grade>III - Dox doxorubicin dose given (whereas CHOP contains 50 mg/m² doxorubicin) - AC adenocarcinoma - NHL Non-Hodgkin's lymphoma - SCLC small-cell lung cancer - CHOP cyclophosphamide/doxorubicin/vincristine/prednisone - COP cyclophosphamide/vincristine/prednisone - VP16/MTX/Cycl etoposide/methotrexate/cyclophosphamide - ProMACE-MOPP prednisone/methotrexate/Adriamycin/cyclophosphamide/etoposide/nitrogen mustard/vincristine/procarbazine/prednisone - FAM(TX) 5-fluorouracil/doxorubicin/mitomycin/methotrexate(TX) - CP cyclophosphamide/cisplatin - CDDP cisplatin - Mitox mitoxantrone - CDE cyclophosphamide/doxorubicin/etoposide - Chl chlorambucil - E/MTX/C etoposide/methotrexate/cyclophosphamide     

Multicenter hypothermia survey

A multicenter survey evaluated the clinical presentation, treatment, and outcome of accidental hypothermia. Data were collected from 13 emergency departments, with 401 of the 428 cases presenting during a two-year study period. Core temperatures ranged from 35 C to 15.6 C (mean, 30.57 C +/- 3.53) with 272 cases (63.6%) less than or equal to 32.2 C. There were no significant differences by age in presenting temperature, rewarming strategies, or mortality. The first hour rewarming rate was significantly (P less than .05) faster in the population less than or equal to 59 years (1.08 +/- 1.39 C/hr) than in those greater than or equal to 60 years (0.75 +/- 1.16 C/hr). Male core temperatures averaged 30.27 +/- 3.44 C versus female temperatures of 31.1 +/- 3.61 C. There were no clinically significant differences in male (N = 296) versus female (N = 132) profiles. High ethanol levels (315 to 800 mg%) did not affect outcome. Nine of 27 (33%) patients who received CPR initiated in the field survived, versus six of 14 (43%) with CPR begun in the ED. The profile of the CPR versus non-CPR population differed significantly (P less than .05) in location (outdoors), initial temperature (24.8 +/- 3.77 C vs 30.94 +/- 3.12 C), third-hour rewarming rate (2.28 +/- 1.53 C vs 1.17 +/- 1.18 C/hr), and numerous laboratory parameters. Tracheal intubation was performed without incident in 117 cases, of which 97 were less than or equal to 32.2 C. There were 73 fatalities (17.1%). Of these, 84.9% (N = 62) were less than or equal to 32.2 C. Predisposing conditions in this group included "serious" illness (30), systemic infection (28), trauma (15), immersion (ten), frostbite (seven), and overdose (two). The initial pulse, hemoglobin, and first-hour rewarming rate was lower in the deceased population, while the potassium, urea nitrogen, creatinine, and phosphorus were elevated. Excluding treatment combinations, outcome with exclusive use of a single rewarming strategy was passive external rewarming, 14 deaths below 32.2 C, 13 above; active external rewarming, six deaths below 32.2 C, two above; active core rewarming, 38 deaths below 32.2 C, none above. Refinements of the American Heart Association's CPR standards in hypothermia and a Hypothermia Survival Index are proposed.     

Potential hazards of hypoglycaemia in the parturient

Hypoglycaemia can cause serious problems in anaesthetized patients, due to blockade by anaesthesia of the usual compensatory mechanisms. Gravid women develop hypoglycaemia more readily than non-pregnant patients because they live in a state of "accelerated starvation." Three cases are described of healthy parturients undergoing elective Caesarean section under lumbar epidural analgesia whose post-blockade hypotension was difficult to reverse until their low blood glucose concentrations had been normalized. Further investigations of the role played by blood glucose concentrations in the maintenance of cardiovascular homeostasis in pregnant women are indicated. In the meantime, a preanaesthetic blood glucose determination will facilitate measures to ensure a normal blood glucose level before induction of anaesthesia for Caesarean section.     

Electrophysiological evidence that early glaucoma affects foveal vision

The pattern electroretinogram (PERG) and visual evoked potential (PVEP) were recorded simultaneously using a 1.1 cpd pattern which was counterphase modulated at 1 Hz. The responses of ocular hypertensive (OHT) eyes (with normal visual fields) and eyes with early glaucoma (with early visual field defects and/or early cupping of the optic nervehead) were compared to age-matched normal observers. All patients (26 eyes) and normal observers (14 eyes) had normal transient flash electroretinograms. Delays were seen in mean PERG latency in both OHT and early glaucoma eyes, while mean PERG amplitude was significantly reduced only in the early glaucoma eyes. The PVEP responses were unmeasurable in 11/26 patient eyes because the waveforms were grossly abnormal in shape, making it impossible to identify the N- and P-components. The data were categorized in this manner: a patient response was considered abnormal if latency or amplitude exceeded normal limits (PERG or PVEP) or if the waveform was unmeasurable due to its shape (PVEP only). Of the 26 patient eyes, we found that 8 eyes had normal PERG and PVEP, 11 eyes had abnormal PERG and PVEP, one eye had an abnormal PERG and a normal PVEP, and 6 eyes (3 patients) had a normal PERG and an abnormal PVEP. These data support the proposition that foveal vision (as assessed by the PVEP) may be affected by early glaucomatous damage. The relationship between the PERG and PVEP also was evaluated using a new measurement which we call the latency window. Using this measurement, 15/26 patient eyes were abnormal - 9 of these had unmeasurable PVEPs. This measurement could be useful in classifying W-shaped PVEPs as normal or abnormal.This study was supported in part by Grants EY01708 and EY01867 from the National Eye Institute, Bethesda, MD, by Fight For Sight Grant-in-Aid G-274, and by an unrestricted grant from Research to Prevent Blindness, Inc., New York, NY.     

An Optimized,Synthetic DNA Vaccine Encoding the Toxin A and Toxin B Receptor Binding Domains of Clostridium difficile Induces Protective Antibody Responses In Vivo

Clostridium difficile-associated disease (CDAD) constitutes a large majority of nosocomial diarrhea cases in industrialized nations and is mediated by the effects of two secreted toxins, toxin A (TcdA) and toxin B (TcdB). Patients who develop strong antitoxin antibody responses can clear C. difficile infection and remain disease free. Key toxin-neutralizing epitopes have been found within the carboxy-terminal receptor binding domains (RBDs) of TcdA and TcdB, which has generated interest in developing the RBD as a viable vaccine target. While numerous platforms have been studied, very little data describes the potential of DNA vaccination against CDAD. Therefore, we created highly optimized plasmids encoding the RBDs from TcdA and TcdB in which any putative N-linked glycosylation sites were altered. Mice and nonhuman primates were immunized intramuscularly, followed by in vivo electroporation, and in these animal models, vaccination induced significant levels of both anti-RBD antibodies (blood and stool) and RBD-specific antibody-secreting cells. Further characterization revealed that sera from immunized mice and nonhuman primates could detect RBD protein from transfected cells, as well as neutralize purified toxins in an in vitro cytotoxicity assay. Mice that were immunized with plasmids or given nonhuman-primate sera were protected from a lethal challenge with purified TcdA and/or TcdB. Moreover, immunized mice were significantly protected when challenged with C. difficile spores from homologous (VPI 10463) and heterologous, epidemic (UK1) strains. These data demonstrate the robust immunogenicity and efficacy of a TcdA/B RBD-based DNA vaccine in preclinical models of acute toxin-associated and intragastric, spore-induced colonic disease.