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 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A substantial body of evidence provides support (but not definitive proof of efficacy) for the use of antiretroviral agents as postexposure prophylaxis for occupational exposures to HIV in the healthcare workplace. Despite the lack of definitive evidence of the efficacy of these agents in this setting, over the past decade this intervention has become the standard of care for healthcare workers who sustain occupational exposures to HIV. Administration of these agents--even for a relatively short 28-day postexposure course--is often fraught with difficulty. All of the agents currently used for postexposure prophylaxis regimens have substantial adverse effects, and significant adverse effects occur in more than two-thirds of individuals electing prophylaxis. This manuscript reiterates current US Federal Government guidelines for the administration of postexposure prophylaxis, specifically noting that zidovudine plus lamivudine (with or without a protease inhibitor) remains the recommended regimen. The paper summarises the significant toxicities associated with nucleoside reverse transcriptase inhibitors (primarily nausea, vomiting, diarrhoea and bone marrow suppression), non-nucleoside reverse transcriptase inhibitors (rash, fever, gastrointestinal symptoms and hepatitis, including hepatic decompensation necessitating liver transplantation) and protease inhibitors (nausea, vomiting, diarrhoea, abdominal pain, hyperglycaemia, hyperlipidaemia, headache and anorexia). As a class, the antiretroviral agents have an extraordinary number of drug interactions. The non-nucleoside reverse transcriptase inhibitors and the protease inhibitors are metabolised through the cytochrome P450 pathway, and the effects of concomitant administration of protease inhibitors with other agents in the same class are discussed, as well as the effects of concomitant administration of protease inhibitors with non-nucleoside agents. The potential for numerous and medically risky drug interactions emphasises the importance of planning antiretroviral prophylaxis in consultation with practitioners or clinical pharmacists who are skilled in the use of these agents and knowledgeable about the potential for significant drug interactions that could either reduce the benefit of prophylaxis or increase the potential for toxicity. Another common problem encountered by individuals managing postexposure prophylaxis programmes relates to the administration of chemoprophylaxis to a pregnant healthcare worker who has sustained an occupational exposure to HIV. We address what is known about the potential for toxicity and emphasise the recently published warning concerning the deaths of pregnant women and their offspring from lactic acidosis while receiving regimens containing stavudine and didanosine.
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PMID:Tolerability of postexposure antiretroviral prophylaxis for occupational exposures to HIV. 1148 Apr 91

Congenital disorders of glycosylation (CDG) and mitochondrial diseases are multisystem disorders with clinical characteristics that may overlap. We present four patients with CDG whose phenotypes suggested the diagnosis of a mitochondrial disease. Patients 1 and 2 are siblings with hemiplegic headache, stroke-like episodes, lactic acidaemia and history of maternal migraine; their initial clinical diagnosis was MELAS syndrome (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes). Patient 3 suffers from ataxia, neuropathy, ophtalmoplegia and retinitis pigmentosa suggestive of NARP (neuropathy, ataxia, and retinitis pigmentosa) syndrome. Patient 4 presented with neurological regression mimicking Leigh disease, with ptosis, myoclonus, ataxia and brainstem and cerebellar atrophy. Screening for mitochondrial disease including enzyme and mtDNA investigations on muscle biopsy were performed on Patients 1, 2 and 4 with normal results. However, evidence for a glycosylation disorder was substantiated by an increased carbohydrate deficient transferrin (CDT). The isoelectric focussing pattern of serum sialotransferrin was typical of CDG type I in Patients 1, 2 and 3 and was shifted towards the less sialylated bands in case 4. A deficiency of phosphomanomutase (PMM) confirmed the diagnosis of CDG-Ia in Patients 1, 2 and 3, who are compound heterozygous for mutations R141H/T237M (Patients 1 and 2) and R141H/P113L (Patient 3). In Patient 4, PMM activity was normal, and further enzymatic and molecular studies are underway. As the search for the primary defect in mitochondrial diseases is often unsuccessful, the pool of mitochondrial patients that remain without definite diagnosis might include CDG cases. Routine screening for CDG may avoid precocious invasive investigations.
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PMID:Congenital disorders of glycosylation (CDG) may be underdiagnosed when mimicking mitochondrial disease. 1158 67

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome has various presentations. We report on a case of MELAS in which alternate-sided homonymous hemianopia was the main symptom of recurrent neurological defects. A 19-year-old woman suffered from blurred vision, headaches, vomiting, and fever that subsided within days. The ophthalmic examination demonstrated right homonymous hemianopia. One month later a similar episode occurred again. Computed tomography (CT) and magnetic resonance imaging (MRI) of her brain revealed an infarct in the left temporo-occipital lobes. Exercise tests showed lactic acidosis, and a muscle biopsy confirmed the diagnosis of mitochondrial myopathy. Half a month later, a third episode occurred. Visual field examination demonstrated left homonymous hemianopia and partial recovery of the right visual field. The infarct in the brain, as revealed by CT and MRI, was compatible with the visual field changes. MELAS should be ruled out in young patients who present with homonymous hemianopia accompanied by recurrent headaches or other recurrent symptoms.
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PMID:Alternate-sided homonymous hemianopia as the solitary presentation of mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes syndrome. 1279 Feb 25

The long-term effects of the sodium salt of dichloroacetic acid (DCA) were evaluated in four patients with mitochondrial encephalomyelopathy with lactic acidosis and stroke-like episodes (MELAS) carrying A3243G mutation. Oral administration of DCA in MELAS patients was followed for an average of 5 years 4 months. Serum levels of lactate and pyruvate were maintained at around 10 and 0.6 mg/dl, respectively. Serum levels of DCA were 40-136 microg/ml. Symptoms responding to treatment included persistent headache, abdominal pain, muscle weakness, and stroke-like episodes. In contrast, no improvements in mental status, deafness, short stature, or neuroelectrophysiological findings were observed. Adverse effects included mild liver dysfunction in all patients, hypocalcemia in three and peripheral neuropathy in one. None of these adverse events was severe enough to require discontinuation of treatment. To determine suitable indications for DCA therapy, analysis of many more patients who have undergone DCA administration is required.
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PMID:Dichloroacetate treatment for mitochondrial cytopathy: long-term effects in MELAS. 1535 Oct 81

Mitochondrial DNA plays a crucial role in oxidative production of energy. Thus, defects in mitochondrial DNA can affect virtually all organ systems. The point mutation A --> G at position 3243 in the mitochondrial tRNAleu(UUR) gene is the cause of several distinct types of mitochondrial cytopathy and several clinical phenotypes, including encephalomyopathy with lactic acidosis and stroke-like episodes and maternally inherited diabetes and deafness. This mutation has been recently described also in association with kidney disease, mainly focal and segmental glomerulosclerosis. At present, little is known about the prevalence of this mitochondrial nephropathy, its clinical course and the pathogenesis of glomerular damage. We describe 2 unrelated patients, who presented with proteinuria and progressed to end-stage renal failure. Other clinical features were short stature, severe headache, hearing loss, diabetes mellitus and hypertrophic cardiomyopathy. The main histological finding was an increased number of abnormal mitochondria in tubular cells and podocytes. Analysis of mitochondrial DNA from leukocytes and urine sediment revealed heteroplasmy for the A3243G mutation in tRNAleu(UUR) gene in both patients. Recognition of the characteristic clinical and histological features of the mitochondrial A3243G mutation-associated glomerulopathy will enable correct diagnosis and better management of a disease which is likely to be underdiagnosed.
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PMID:Progressive nephropathy associated with mitochondrial tRNA gene mutation. 1535 73

The majority of patients with MELAS (mitochondrial encephalomyopathy, lactic acidosis, and strokelike episodes) have the A3243G point mutation. The much rarer T3271C mutation has been reported predominantly in Japanese subjects. Our objective was to better define the clinical phenotype and mutation load in patients with MELAS and the T3271C mutation in mitochondrial DNA. We present clinical and molecular genetic data in two pedigrees with the T3271C mutation. The age at onset was 8 years in one proband and 14 years in the other. Both patients had migrainelike headache, seizures, and strokelike episodes. Mutation loads were quantified in multiple tissues from the patients and from family members by polymerase chain reaction-restriction fragment length polymorphism analysis. The symptoms in both probands were typical of MELAS, and, contrary to previous reports, onset was early. Hearing loss was less common than in typical MELAS, and ragged red fibers were absent. The proportion of mutant genomes was consistently and markedly greater in DNA from urinary sediment than from blood. In the mother of one proband, mutant genomes were detected only in DNA from hair follicles and cheek mucosa The phenotype of patients with the T3271C mutation might not be as distinct as that of the A3243G mutation, as previously described. Our data also suggest that urine is a better source of DNA than blood for diagnosis and that multiple tissues should be studied in maternal relatives, especially when the mutation cannot be detected in blood.
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PMID:Clinical and genetic features in two families with MELAS and the T3271C mutation in mitochondrial DNA. 1579 82

Patients with migraine are at increased risk for white matter hyperintensities detected on magnetic resonance imaging. The presence of nonspecific white matter hyperintensities may cause uncertainty for physicians and anxiety for patients. The pathophysiology and long-term consequences of these lesions are unknown. Occasionally, white matter lesions in a migraineur may indicate an underlying disease such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS), or central nervous system vasculitis. The ability to distinguish between nonspecific and disease-specific patterns of white matter hyperintensities in migraine sufferers is important for the practicing clinician.
Curr Pain Headache Rep 2005 Aug
PMID:Migraine and white matter hyperintensities. 1600 47

We report herein the case of a 28-year-old man presenting with hyperglycemic chorea-ballism (HCB) in addition to mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). He was admitted to a local hospital due to weight loss, general fatigue and thirst. The patient had diabetes mellitus, with a blood glucose level of 738 mg/dl and HbA1c of 19.8%. Although insulin therapy improved hyperglycemia, he noticed involuntary movements in the right upper and lower limbs, which subsequently extended to the left side. The patient was thus transferred to our hospital. He displayed short stature (154 cm) and emaciation, and a maternal family history of diabetes mellitus was elicited. He had no history of stroke-like episode, headache, vomiting and seizure. Neurological examination revealed low intelligence (IQ 57), mild sensorineural deafness, and chorea-ballism in the extremities and head without ptosis or eye movement disturbance. Brain computed tomography (CT) demonstrated areas of high density, while T1-weighted magnetic resonance imaging (MRI) revealed extreme hyperintensity and T2-weighted MRI showed hyperintensity in bilateral caudate nuclei, putamina and globi pallidus. HCB was diagnosed. In, CSF, lactate level was increased to 43.9 mg/dl (n, 4-16), pyruvate level was 1.65 mg/dl (n, 0.3-0.9) and total protein concentration was 59 mg/dl. Histological examination of a biopsy sample from the biceps brachii muscle demonstrated ragged-red fibers. An A3243G point mutation in the tRNA(Leu(UUR)) gene was detected, indicating the presence of MELAS. Involuntary movements improved on treatment with haloperidol up to 4.5 mg/day. HCB usually appears in elderly individuals, and cases less than 40-years-old are very rare. The mitochondrial dysfunction in MELAS may accelerate development of HCB.
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PMID:[A case of MELAS presenting juvenile-onset hyperglycemic chorea-ballism]. 1611 32

Mitochondrial disorders are an uncommon, but important, cause of stroke-like clinical and imaging presentations in individuals under the age of 45 years. We present a 31-year-old man with a 4-year history of migraine-like headaches, type 2 diabetes mellitus, seizures, and hearing loss. Magnetic resonance imaging revealed multiple hyperintensities on T2 and fluid-attenuated inversion recovery sequences. An exhaustive work-up for vasculitis including brain biopsy was performed. Mitochondrial DNA testing revealed the A3243G substitution associated with the mitochondrial encephalomyopathy with lactic acidosis and stroke syndrome. In this case review we briefly discuss the signs and symptoms, frequency, pathophysiology, and prognosis of this disorder.
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PMID:Mitochondrial encephalomyopathy with lactic acidosis and stroke (MELAS). 1640 Mar 2

Mitochondrial encephalopathy, lactic acidosis with stroke-like episodes (MELAS) is a rare mitochondrial disorder that affects adults. MELAS syndrome can mimic cerebrovascular disease, encephalitis or toxic-metabolic encephalopathy. The authors reported two patients who presented with auditory symptoms before the onset of encephalopathy and stroke-like episodes. The first patient was a 28 year-old man, who presented with acute sensorineural hearing loss (SNHL) followed by headache, left hemiparesis and generalized tonic-clonic seizure. CT scan of the brain showed hypodensity lesion at the tip of right temporooccipital region. Audiogram and brainstem auditory evoked potential (BAEP) showed abnormal conduction of left brainstem auditory pathway. MRI of the brain showed a lesion involving gray and white matters of the right occipital, parietal and temporal lobes. The distribution of the lesions was not compatible with distribution of arterial supply. MRA was normal. The second patient was a 56 year-old woman with a one-year history of hearing loss. The audiogram revealed bilateral SNHL. A few days before admission, her hearing was acutely deteriorated She could not understand a conversation while she could communicate by writing. CT scan of the brain showed hypodensity in both temporal lobes and MRI revealed lesions in the same area. Pure tone audiogram showed moderate SNHL but BAEP was normal. One week later, she developed global dysphasia and generalized tonic-clonic seizure. Both patients had elevated cerebrospinal fluid and serum lactate: pyruvate ratio. Polymerase chain reaction-restriction fragment length polymorphism disclosed A3243G mtDNA mutation in the blood in the first patient and in muscle biopsy in the second patient. Ubiquinone supplement was prescribed The auditory symptoms in combination with stroke-like episode in supratentorium are important clues to diagnose MELAS syndrome.
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PMID:Auditory symptoms: a critical clue for diagnosis of MELAS. 1647 Nov 25


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