Biomedical subjects

Rocco Liguori

Publications and source records attributed to Rocco Liguori.

14 recordsLinked to original sources

PubMed2006

Parallel changes in resting muscle sympathetic nerve activity and blood pressure in a hypertensive OSAS patient demonstrate treatment efficacy.

Studies comparing the efficacy of continuous positive airway pressure (CPAP) versus surgery in correcting cardiovascular abnormalities in OSAS are lacking. We describe an OSAS patient with hypertension who responded favorably to CPAP treatment, whereas subsequent uvulopalatopharyngoplasty (UPPP) was less successful. While CPAP markedly lowered daytime muscle sympathetic nerve activity (MSNA) and blood pressure (BP), findings after UPPP were comparable to pre-treatment baseline. Thus, parallel changes in MSNA and BP demonstrated treatment efficacy.

Blood Pressure↗

PubMed2006

Influence of peer review medical audit on pathophysiological interpretation of nerve conduction studies in polyneuropathies.

OBJECTIVE: To evaluate the possible influence of peer review medical audit on experienced physicians' pathophysiological interpretation of nerve conduction studies in polyneuropathy patients. METHODS: Since 1992, 7 European neurophysiologists have collected samples of their patient examinations for regular review where the physicians interpret each other's cases electronically and subsequently discuss them at regular workshop meetings (i.e. a form of medical audit). Two sets of 100 polyneuropathy examinations interpreted with an interval of 4-6 years were selected. The sets contained 1456 and 1719 nerve conduction studies, each given a pathophysiological test conclusion by each individual physician. Inter-physician agreement on interpretation of demyelination and axonal loss of the nerve, as well as neuropathic and unspecific findings, was estimated using kappa statistics. RESULTS: Increased agreement from set 1 to set 2 was found on interpretation of demyelination of the nerve (set 1: kappa=0.22; set 2: kappa=0.45), and of neuropathic (set 1: kappa=0.46; set 2: kappa=0.64) and unspecific findings (set 1: kappa=0.35; set 2: kappa=0.54). No changes were found on interpretation of axonal loss (set 1: kappa=0.26; set 2: kappa=0.31) and normal findings (set 1 and set 2: kappa=0.90). CONCLUSIONS: Participation in regular peer review medical audit resulted in increased agreement on interpretation of nerve conduction studies for 6 of the 7 participants. The study further highlights the need for better definition of criteria for identification of demyelinating, and in particular, axonal peripheral neuropathies. SIGNIFICANCE: International collaboration involving peer review medical audit may contribute to development of practice guidelines and, in turn, to increased quality of electrodiagnostic medicine.

Axons↗

PubMed2006

Differentiation of chromaffin cells in the developing adrenal gland of Testudo hermanni.

The aim of this study was to investigate the development and differentiation of chromaffin cells in the adrenal gland of the turtle Testudo hermanni during ontogenesis using histological, immunocytochemical and ultrastructural methods. The 26 developmental stages were divided into three periods: in the early period (stages 1-18, up to 20 days of incubation at 37 degrees Celsius and 85% humidity), the chromaffin cells were observed from stage 12. They followed a ventro-lateral migration pathway with respect to the notochord and dorsal aorta, forming groups embedded in undifferentiated mesenchymal tissue. They reached the kidney surface only at the end of this period. Under the EM the chromaffin cells showed typical embryonic characters, such as rounded shape, high nucleus/plasmatic ratio, cell membrane with elongated processes; the cytoplasm contained a large number of free ribosomes, Golgi complexes, RER and a few chromaffin granules distributed in small sets. The granules were small and displayed a high electrondensity. Numerous unmyelinated fibres ran close to the chromaffin cells. At the end of this period both nervous elements and chromaffin cells were positive to the antigen for DbetaH. The intermediate period (stages 19-22, incubation days 21-35) was characterized by the first occurrence of steroidogenic cells on the ventro-medial kidney surface. Some chromaffin cells were still found in the same position, whereas other cells were still migrating, maintaining their embryonic character. It was possible to divide the secretory granules into two types according to their shape and electrondensity: the more numerous N-type granules had a dark content, whereas the small number of A-type granules (consistent with the scarce PNMT reaction) displayed a light content. They occurred for the first time in this period. In the advanced period (stages 23-26, from incubation day 36 to hatching) the adrenal gland reached its definitive shape, although remaining immature; groups of variously sized chromaffin cells intermingled with steroidogenic cells, both lying on the kidney surface. Chromaffin granules were more numerous and larger than in the previous stages, frequently mingling in the same cell. A migration pathway of the chromaffin cells along the nerve fibres can be hypothesized on the basis of their common origin and closeness. The polymorphic shape of chromaffin cells with long cytoplasmic processes also accounts for their migrating fitness. We can assume that steroidogenic differentiation from the mesodermic blastema begins after the first chromaffin cells have completed their migration.

Adrenal Glands↗

PubMed2006

Skin sympathetic adrenergic innervation: an immunofluorescence confocal study.

OBJECTIVE: The aim of this study was to characterize sympathetic adrenergic innervation of the skin in healthy subjects using dopamine beta hydroxylase (DbetaH) as a specific marker for noradrenergic fibers. METHODS: Sympathetic adrenergic innervation of human skin was studied in 10 healthy subjects by indirect immunofluorescence and confocal microscopy applied to punch skin biopsies. Noradrenergic fibers were identified both in glabrous and hairy skin using DbetaH antibody. RESULTS: DbetaH immunoreactive fibers were mainly localized in arteriovenous anastomoses, arrector pilorum muscles, and arterioles, whereas few adrenergic fibers were found around sweat glands. INTERPRETATION: Our description of sympathetic adrenergic innervation of human skin aims to improve the diagnostic ability of skin biopsy to detect selective autonomic nervous system disorders.

Adult↗

PubMed2006

Mitochondrial neurogastrointestinal encephalomyopathy: evidence of mitochondrial DNA depletion in the small intestine.

BACKGROUND & AIMS: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disease clinically defined by gastrointestinal dysmotility, cachexia, ptosis, ophthalmoparesis, peripheral neuropathy, white-matter changes in brain magnetic resonance imaging, and mitochondrial abnormalities. Loss-of-function mutations in thymidine phosphorylase gene induce pathologic accumulations of thymidine and deoxyuridine that in turn cause mitochondrial DNA (mtDNA) defects (depletion, multiple deletions, and point mutations). Our study is aimed to define the molecular basis of gastrointestinal dysmotility in a case of MNGIE. METHODS: By using laser capture microdissection techniques, we correlated histologic features with mtDNA abnormalities in different tissue components of the gastrointestinal wall in a MNGIE patient and ten controls. RESULTS: The patient's small intestine showed marked atrophy and mitochondrial proliferation of the external layer of muscularis propria. Genetic analysis revealed selective depletion of mtDNA in the small intestine compared with esophagus, stomach, and colon, and microdissection analysis revealed that mtDNA depletion was confined to the external layer of muscularis propria. Multiple deletions were detected in the upper esophagus and skeletal muscle. Site-specific somatic point mutations were detected only at low abundance both in the muscle and nervous tissue of the gastrointestinal tract. Analysis of the gastrointestinal tract from 10 controls revealed a non-homogeneous distribution of mtDNA content; the small intestine had the lowest levels of mtDNA. CONCLUSION: Atrophy, mitochondrial proliferation, and mtDNA depletion in the external layer of muscularis propria of small intestine indicate that visceral myopathy is responsible for gastrointestinal dysmotility in this MNGIE patient.

Adult↗

PubMed2006

Autosomal dominant early-onset cortical myoclonus, photic-induced myoclonus, and epilepsy in a large pedigree.

PURPOSE: Cortical tremor, a form of rhythmic cortical myoclonus (rhythmic CM), and epilepsy have been described in families with autosomal dominant inheritance. Linkage analyses revealed two putative loci on chromosome 2p and 8q. Clinical photosensitivity was not a prominent feature in such families. We describe a large Italian family with rhythmic CM, photosensitivity, and epilepsy. METHODS: Twenty-three individuals of a five-generation family were studied. Linkage analyses for the loci on chromosome 2p11.1 and 8q23.3 were performed. RESULTS: Of the 23 studied family members, 16 were affected. Rhythmic CM of childhood onset was present in all 16 individuals (onset ranging from 3 to 12 years), was associated with photic-induced myoclonic jerks in seven, and with epileptic seizures in six (onset ranging from 23 to 34 years). Five children of the V generation manifested also episodes of arousal with generalized tremor in early infancy ("tremulous arousals"). Jerk-locked back-averaging of rhythmic CM of six affected individuals, documented a premyoclonic EEG correlate. C-reflex at rest was present in two affected adults. Linkage analyses excluded mapping to the 2p11.1 and 8q23.3 loci. CONCLUSIONS: Clinical variability and severity of the phenotypes in this family are in line with those of previously described pedigrees with autosomal dominant cortical myoclonus and epilepsy. In this family, a progression of symptoms was found: rhythmic CM and tremulous arousals occurred in childhood, whereas visually induced manifestations and epileptic seizures occurred during adolescence-adulthood. Exclusion of linkage to the two known loci is consistent with genetic heterogeneity of such familial clustering of symptoms.

Age of Onset↗

PubMed2005

Continuous motor unit activity syndromes: a video-polysomnographic study.

OBJECTIVE: To ascertain the presence of abnormalities of sleep in patients with continuous motor unit activity with and without symptoms of central nervous system involvement. METHODS: Five patients with isolated neuromyotonia (Isaacs' syndrome) and 1 patient with Morvan syndrome underwent 24-h videopolysomnographic recording to investigate sleep structure, motor activities and autonomic variables during sleep. RESULTS: Macro- and microstructural organization of sleep and of the attending autonomic variables were substantially normal in patients with Isaacs' syndrome. On the contrary, sleep structure was severely disrupted with subcontinuous dream enactment and hallucinations in the patient with Morvan syndrome. The pattern of the neuromyotonic discharges, however, was not different between the patients with Isaacs' syndrome compared to Morvan syndrome, the EMG discharges persisting throughout the 24 h of recording and affecting wakefulness and sleep equally. CONCLUSIONS: Neuromyotonia is compatible with normal organization of sleep. The severe sleep abnormalities observed in Morvan syndrome cannot be simply attributed to the effects of neuromyotonia of peripheral origin. SIGNIFICANCE: Even though neuromyotonia is common to both Isaacs' and Morvan syndromes, the two conditions differ significantly in regard to CNS involvement with sleep abnormalities and lumping the two conditions together is not justified on clinical and neurophysiological grounds.

Adolescent↗

PubMed2005

Habituation of sympathetic sudomotor and vasomotor skin responses: neural and non-neural components in healthy subjects.

OBJECTIVE: Sympathetic skin response (SSR) and skin vasomotor response (SVR) habituation was thought to be induced by neural mechanisms. Here, we investigate the hypothesis that non-neural mechanisms could also be involved. METHODS: We recorded sympathetic skin nerve activity (SSNA) from median nerve by microneurography and the corresponding SSR and SVR in 16 healthy subjects. Superficial electrical stimulation of the opposite median nerve was used to induce arousal responses. RESULTS: Throughout stimulation, SSNA, SSR and SVR amplitude showed a significant reduction. During the first ten stimuli, SSNA showed a marked decrease highly correlated to SSR and SVR changes. During the subsequent 20 stimuli SSNA did not change whereas SSR and SVR significantly decreased. SVR was significantly influenced by skin temperature changes. CONCLUSIONS: Both neural and non-neural mechanisms are involved in SSR and SVR habituation. The neural mechanisms were predominant during the first part of stimulation whereas non-neural mechanisms prevailed during the last part of stimulation. SIGNIFICANCE: During repeated arousal stimuli SSR and SVR amplitude changes did not reflect the strength of the corresponding sympathetic nerve traffic and must be interpreted with caution.

Adult↗

PubMed2005

Influence of medical audit on electrodiagnostic evaluation of polyneuropathy. A multicentre study.

OBJECTIVE: Since 1992, 7 European neurophysiologists have participated in the ESTEEM project concerned with improvements in electrodiagnostic medicine. This study assesses whether the collaboration that includes peer review medical audit has influenced the involved physicians' electrodiagnostic criteria for polyneuropathy (PNP) diagnosing and classification. METHODS: Two sets of each physician's PNP examinations performed early and late in the study were examined for changes in (1) number of studies with abnormal electrophysiological findings required for diagnosing PNP, and (2) agreement between the classifications given by the individual physicians and the peer review group. RESULTS: The average number of abnormal motor nerve segments per patient increased from 4.6 to 6.4 during the study. Although most individual changes were minor, the second set of examinations showed an increased homogeneity among the physicians in the number of abnormal motor nerve segments and abnormal F wave studies, and a tendency towards increased homogeneity in the number of abnormal sensory nerve segments. There was also an increased agreement on pathophysiological PNP classification in the second set of examinations compared to the first set. CONCLUSIONS: The participation in the ESTEEM project seems to have impacted the physicians' clinical routine, possibly as they have accustomed themselves to apply criteria more strictly. SIGNIFICANCE: This study support that international collaboration is a useful step towards improvements in electrodiagnostic medicine.

Analysis of Variance↗

PubMed2005

Pathophysiology inferred from electrodiagnostic nerve tests and classification of polyneuropathies. Suggested guidelines.

OBJECTIVE: To present criteria for pathophysiological interpretation of motor and sensory nerve conduction studies and for pathophysiological classification of polyneuropathies suggested by a group of European neurophysiologists. METHODS: Since 1992 seven neurophysiologists from six European countries have collected random samples of their electrodiagnostic examinations for peer review medical audit in the ESTEEM (European Standardized Telematic tool to Evaluate Electrodiagnostic Methods) project. Based on existing criteria in the literature, the experience with a patient material of 572 peer reviewed electrodiagnostic examinations, and productive discussions between the physicians at workshops, the collaboration has produced a set of criteria now routinely used at the centres involved in the project. RESULTS: The first part of the paper considers pathophysiology of individual nerve segments. For interpretation of motor and sensory nerve conduction studies, figures showing change in amplitude versus change in conduction velocity/distal latency and change in F-wave frequency versus change in F-wave latency are presented. The suggested boundaries delimit areas corresponding to normal, axonal, demyelinated, or neuropathic nerve segments. Criteria for motor conduction block in upper and lower extremities are schematically depicted using the parameters CMAP amplitude and CMAP duration. The second part of the paper suggests criteria for classification of polyneuropathies into axonal, demyelinating, or mixed using the above-mentioned criteria. CONCLUSIONS: The suggested criteria are developed during many years of collaboration of different centres and may be useful for standardization in clinical neurophysiology. SIGNIFICANCE: Consistent interpretation of nerve conduction studies is an important step in optimising diagnosis and treatment of nerve disorders.

Axons↗

PubMed2004

Molecular biology of channelopathies: impact on diagnosis and treatment.

Channelopathies are genetically determined ion channel alterations that lead to acute and transient symptoms in subjects who otherwise appear to be normal. This article reviews the recent progression of biomolecular studies that have clarified the mechanisms by which gene mutations may result in alterations of excitable tissues responsible for episodic neurological, neuromuscular and cardiac disorders, defined as channelopathies. The development of technologies capable of testing pharmacological agents in vitro on mutated channels expressed in cell lines makes it possible to define a more rational use of the available drugs acting on ion channels, and to design new molecules specifically targeted to known channel dysfunctions and new ones that could be identified by future genetic studies.

Central Nervous System Diseases↗

PubMed2003

Sympathetic skin response: basic mechanisms and clinical applications.

Sympathetic skin response (SSR), defined as the momentary change of the electrical potential of the skin, may be spontaneous or reflexively evoked by a variety of internal or by externally applied arousal stimuli. Although the suprasegmental structures influencing the SSR in humans are not well known, SSR has been proposed as a non-invasive approach to investigate the function of the sympathetic system. SSR is easy to apply but current procedures are not sufficiently reliable for diagnostic purposes, and show imperfect correlations both with clinical features and other measurements of autonomic, in particular, sudomotor dysfunction.

Animals↗

PubMed2002

Electrophysiological findings in X-linked myopathy with excessive autophagy.

We report electrophysiological features and magnetic resonance imaging muscle findings in 4 patients and 1 female carrier of X-linked myopathy with excessive autophagy. Motor units were polyphasic with high mean amplitude and normal duration. The thigh muscles were most severely involved, but myotonic discharges were abundant in both clinically affected and unaffected muscles. Along with the clinicopathological features, these electrophysiological findings distinguish X-linked myopathy with excessive autophagy from other limb-girdle myopathies.

Adolescent↗

PubMed2002

Excessive fragmentary hypnic myoclonus: clinical and neurophysiological findings.

BACKGROUND: Brief involuntary sleep-related twitches occurring asymmetrically throughout the body define physiologic hypnic fragmentary myoclonus. An abnormal intensification of this entity identifies excessive fragmentary hypnic myoclonus (EFHM), a 'proposed sleep disorder' in the International Sleep Disorders Classification. METHODS: We describe two patients with EFHM, one associated with a REM behaviour disorder. RESULTS: EFHM activity was restricted to sleep prevailing during NREM sleep stages and the second part of the night. EMG was normal and EEG-EMG back-averaging did not show any cortical potentials related to the twitches. CONCLUSIONS: EFHM represents a pathological phenomenon which may or may not be associated with other sleep disorders. A brainstem generator explains its distribution throughout the body and the sleep stages.

Journal Article↗