PubMed Health⌕ Search

Biomedical subjects

D Orrico

Publications and source records attributed to D Orrico.

18 recordsLinked to original sources
PubMed2005

'Neurographic' palmaris brevis sign in type II degrees ulnar neuropathy at wrist.

OBJECTIVE: To investigate the source of an unusual and previously unreported volume conducted potential on motor nerve conduction studies. In a case of subacute ulnar neuropathy at wrist (UNW) selectively involving the deep motor branch, we recorded from the hypothenar eminence a large positive wave (2.5 ms-2 mV) preceding the negative takeoff of the delayed distal ulnar motor response. METHODS: We performed multiple channels motor and sensory ulnar nerve (UN) conduction studies; these included selective electrical stimulation and anaesthetic block of UN branches and also selective recording of motor responses by single fibre needles; data were confirmed by an intraoperative neurophysiological study and correlated with MRI and surgical findings. RESULTS: Detailed neurophysiological investigation demonstrated the generation of this waveform from the palmaris brevis (PB) muscle. MRI and surgical exploration documented a hypertrophy of this muscle. CONCLUSIONS: In type II degrees UNW, depolarization of a spared palmaris brevis muscle may be recorded as a positive wave preceding the delayed abductor digiti minimi motor response. SIGNIFICANCE: We underline the peculiar localizing value of this volume conducted 'meaningful artefact' in that particular setting. It actually represented an early neurographic analogue of what is known as the clinical 'Palmaris Brevis Sign' in long standing type II degrees UNW.

Action Potentials↗
PubMed1999

Myelin uncompaction in Charcot-Marie-Tooth neuropathy type 1A with a point mutation of peripheral myelin protein-22.

BACKGROUND: The peripheral myelin protein-22 (PMP22) gene has four transmembrane domains, two extracellular loops, and a short cytoplasmic tail. Its roles in the peripheral nervous system remain unclear. The most common cause of Charcot-Marie-Tooth neuropathy type 1A (CMT1A) is a PMP22 gene duplication. Missense point mutations in the transmembrane domains are rare alternative causes that have undetermined pathogenetic mechanisms. OBJECTIVE: To investigate the phenotype-to-genotype correlations in a pedigree with unusual CMT1A. METHODS: We identified a pedigree with an autosomal dominant motor-sensory neuropathy and severely reduced nerve conduction velocities who did not have the PMP22 duplication. Specimens from sural nerve biopsies from two patients of different ages were evaluated morphometrically. By automated direct nucleotide sequencing we analyzed PMP22 and the gene of the major structural myelin protein zero (P0). RESULTS: Nucleotide 159 of PMP22 showed an A-to-T heterozygous mutation, predicted to cause an aspartate-to-valine substitution at codon 37 in the first extracellular loop of the protein. The mutation co-segregated with the disease in the pedigree and was absent in 80 healthy controls. The histopathologic phenotype was a de-remyelinating neuropathy with onion bulb formations, characterized by prominent uncompaction of the myelin sheath in the majority of fibers and by frequent tomacula. CONCLUSION: We have described a novel mutation in the first extracellular loop of PMP22 associated with an atypical CMT1A that overlaps pathologically with CMT1B caused by point mutations in the extracellular domain of P0.

Adult↗
PubMed1998

Isolated hypoglossal nerve palsy due to an anomalous vertebral artery course: report of two cases.

The authors report two patients with isolated unilateral tongue atrophy. Magnetic resonance imaging (MRI) of the brain stem and angio-MRI demonstrated a dolichovertebral artery with an abnormal course compressing the medulla oblongata at the emergence of the hypoglossal rootlets. The semeiological observation of a sectorial and not uniform distribution of atrophy in the half-affected tongue is discussed in relation to the lesional site.

Aged↗
PubMed1996

Psychiatric disorder in a familial 15;18 translocation and sublocalization of myelin basic protein of 18q22.3.

Two related patients with similar clinical features consisting of a few dysmorphic signs and psychiatric disturbance were reported to have a partial trisomy of chromosomes 15(pter-q13.3) and 18(q23-qter) deriving from a familial translocation t(15;18). One patient is affected by bipolar disorder and the other by schizoaffective disorder. Both cases have a predominantly affective course; nevertheless, a clear diagnosis is difficult in the first patient, who is 15 years of age, and only a longitudinal course will allow us to establish a definite diagnosis. The possibility that these two pathologies belong to a single category is discussed, and the presence of a susceptibility locus on chromosome 18 is hypothesized. Cytogenetic data, FISH, and DNA studies indicate that the myelin basic protein (MPB) gene is not involved in the translocation, and localize it centromeric to the breakpoint on chromosome 18(q22.3). Thus, it is unlikely to be involved in the disease.

Adolescent↗
PubMed1996

Telephone transmission of 20-channel digital electroencephalogram using lossless data compression.

BACKGROUND: The use of telecommunications for computer-assisted transmission of neurophysiological signals is a relatively new practice. With the development of digital technology, it is now possible to record electroencephalograms (EEGs) in digital form. Previous reports have demonstrated the possibility of real-time telephone transmission of a limited number of EEG channels. OBJECTIVES: To assess the effectiveness of specific data-compression software to improve the transmission of digital 20-channel EEG records over ordinary public telephone lines. METHODS: A prototype system was built to transmit digital EEG signals from one computer to another using two 14.4-kbps modems and proprietary lossless data-compression software. RESULTS: Forty compressed digital EEG records of 20 channels each were sent from different locations at variable distances using "plain old telephone service" (POTS). The mean compression ratio was 2.2 to 2.8:1 using a sampling frequency of 128 Hz and 2.8:1 at a sampling rate of 256 Hz. Transmission time was reduced proportionately. CONCLUSION: Although this study used a store-and-forward approach, the results suggest that it may be possible to transmit a large number of compressed EEG channels in real time using data compression.

Electroencephalography↗
PubMed1992

AZT-induced mitochondrial myopathy.

Histochemical, electron microscopy and biochemical studies were performed on muscle biopsy specimens from 11 AIDS patients treated with zidovudine. A peculiar association of structural abnormalities and mitochondrial dysfunction was found. Focal cytochrome c oxidase (COX) deficiency was evident in muscle sections from 9 patients, 8 of whom had received long-term treatment while one had been treated for 1 month only. Electron microscopy showed changes in number, size and structure of mitochondria. Biochemical studies proved partial COX and succinate cytochrome c reductase (SCR) deficiency in 4 patients; one patient had only reduced SCR activity. Our data confirm that AZT therapy can cause toxic myopathy with mitochondrial dysfunction.

Adult↗
PubMed1991

Minipolymyoclonus in congenital nemaline myopathy: a nonspecific clinical marker of neurogenic dysfunction.

The authors report a seven-month-old boy with severe hypotonia, poor spontaneous movements, breathing difficulties and recurrent respiratory infections, dysmorphisms and a peculiar movement disorder: minipolymyoclonus (MPM), previously reported only in spinal muscular atrophies. MPM is characterized by nonrhythmic myoclonic jerks associated with a rhythmic tremor of the extended fingers polygraphically detected. A muscle biopsy showed pathological changes typical of congenital nemaline myopathy (CNM). The relationship between MPM and CNM may be explained on the presumptive basis of the "neurogenic" nature of this congenital myopathy or by the non-specificity of this clinical sign.

Biopsy↗
PubMed1978

Hypokalemic periodic paralysis. A single fiber electromyographic study.

The neurophysiological findings obtained with standard electromyography (EMG) and single fiber EMG (SFEMG) in a case of hypokalemic periodic paralysis (HoPP) are reported. During the period between paralytic attacks the only abnormalities consisted of scanty fibrillation potentials and, with SFEMG, a fiber density increase. In the first stage of an induced paralytic attack the most striking feature was decrease in fiber density, slight increase in jitter with several blocks. These results indicate a failure of the membrane surface to propagate an action potential. In some fibers the block is likely to be permanent, thus explaining the decrease in fiber density. The jitter increase is due to a slight abnormality at the synaptic site or to a variation in the propagation velocity of the muscle fiber.

Adult↗