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Biomedical subjects

D Mei

Publications and source records attributed to D Mei.

14 recordsLinked to original sources
PubMed2006

Periventricular heterotopia: phenotypic heterogeneity and correlation with Filamin A mutations.

Periventricular heterotopia (PH) occurs when collections of neurons lay along the lateral ventricles or just beneath. Human Filamin A gene (FLNA) mutations are associated with classical X-linked bilateral periventricular nodular heterotopia (PNH), featuring contiguous heterotopic nodules, mega cisterna magna, cardiovascular malformations and epilepsy. FLNA encodes an F-actin-binding cytoplasmic phosphoprotein and is involved in early brain neurogenesis and neuronal migration. A rare, recessive form of bilateral PNH with microcephaly and severe delay is associated with mutations of the ADP-ribosylation factor guanine nucleotide-exchange factor-2 (ARFGEF2) gene, required for vesicle and membrane trafficking from the trans-Golgi. However, PH is a heterogeneous disorder. We studied clinical and brain MRI of 182 patients with PH and, based on its anatomic distribution and associated birth defects, identified 15 subtypes. Classical bilateral PNH represented the largest group (98 patients: 54%). The 14 additional phenotypes (84 patients: 46%) included PNH with Ehlers-Danlos syndrome (EDS), temporo-occipital PNH with hippocampal malformation and cerebellar hypoplasia, PNH with fronto-perisylvian or temporo-occipital polymicrogyria, posterior PNH with hydrocephalus, PNH with microcephaly, PNH with frontonasal dysplasia, PNH with limb abnormalities, PNH with fragile-X syndrome, PNH with ambiguous genitalia, micronodular PH, unilateral PNH, laminar ribbon-like and linear PH. We performed mutation analysis of FLNA in 120 patients, of whom 72 (60%) had classical bilateral PNH and 48 (40%) other PH phenotypes, and identified 25 mutations in 40 individuals. Sixteen mutations had not been reported previously. Mutations were found in 35 patients with classical bilateral PNH, in three with PNH with EDS and in two with unilateral PNH. Twenty one mutations were nonsense and frame-shift and four missense. The high prevalence of mutations causing protein truncations confirms that loss of function is the major cause of the disorder. FLNA mutations were found in 100% of familial cases with X-linked PNH (10 families: 8 with classical bilateral PNH, 1 with EDS and 1 with unilateral PH) and in 26% of sporadic patients with classical bilateral PNH. Overall, mutations occurred in 49% of individuals with classical bilateral PNH irrespective of their being familial or sporadic. However, the chances of finding a mutation were exceedingly gender biased with 93% of mutations occurring in females and 7% in males. The probability of finding FLNA mutations in other phenotypes was 4% but was limited to the minor variants of PNH with EDS and unilateral PNH. Statistical analysis considering all 42 mutations described so far identifies a hotspot region for PNH in the actin-binding domain (P < 0.05).

Abnormalities, Multiple↗
PubMed2005

Multiple attack study on the available triptans in Italy versus placebo.

The aim of the study is to evaluate the efficacy and tolerability of the five triptans that are commercially available in Italy (zolmitriptan 2.5 mg, rizatriptan 10 mg, sumatriptan 100 mg, almotriptan 12.5 mg and eletriptan 40 mg). The study was conducted in single-blind versus placebo and its duration was 18 months. At the Headache Centre of the 'Agostino Gemelli' Hospital in Rome we selected 42 patients, suffering from headache with and without aura (International Headache Society Committee on Headache Classification, 1988 Cephalalgia 8:1-96), whose headache frequency ranged between 1- and 4-monthly crises. For a total of 25 crises, for every five consecutive crises, a different triptan was taken. The end-points of the study were as follows: response at 2 h, 'pain free' at 2 h and 'sustained pain free' (at 24 h). The intra-patient consistency and the tolerability were also evaluated. Thirty patients completed the study and the statistical analysis was only applied to these patients. No substantial difference in terms of the efficacy of the triptans was noted; all triptans were well tolerated. These results suggest the possibility of testing different triptans in the same patient in order to identify the ideal drug for every patient.

Adult↗
PubMed2004

Germline and mosaic mutations of FLN1 in men with periventricular heterotopia.

OBJECTIVE: To describe the phenotypic spectrum and genetics of periventricular nodular heterotopia (PNH) caused by FLN1 mutations in four men. BACKGROUND: X-linked PNH caused by FLN1 mutations (MIM #300049) implies prenatal or early postnatal lethality in boys and 50% recurrence risk in daughters of affected women. METHODS: Clinical examination, cognitive testing, MRI, and mutation analysis (denaturing high-performance liquid chromatography and direct sequencing) on blood lymphocytes and single hair roots were performed for nine affected individuals, including three men. Neuropathologic study of the brain was performed for an affected boy. RESULTS: In two families, missense mutations were transmitted from mother to son (Met102Val) and from father to daughter (Ser149Phe), causing mild phenotypes in both genders, including unilateral PNH. In a third family, a man was mosaic for an A>G substitution (intron 11 acceptor splice site) on leukocyte DNA and hair roots (mutant = 42% and 69%). Single hair root analysis confirmed that the mutation was not present in all ectodermal derivative cells. A healthy daughter had inherited the X chromosome from her father's wild-type germinal cell population. In the fourth family, an eight-base deletion (AGGAGGTG, intron 25 donor splice site) led to early deaths of boys. Postmortem study in a newborn boy revealed PNH and cardiovascular, genitourinary, and gut malformations. CONCLUSIONS: Periventricular nodular heterotopia caused by FLN1 mutations in men has a wide clinical spectrum and is caused by different genetic mechanisms, including somatic mosaicism. Mutation analysis of FLN1 should support genetic counseling in men with periventricular nodular heterotopia.

Abnormalities, Multiple↗
PubMed2004

Topiramate in migraine prophylaxis: a randomised double-blind versus placebo study.

The objectives of this paper are to evaluate the efficacy and tolerability of topiramate, given at the dose of 100 mg/day, in the prophylactic treatment of migraine. The hypothesis that migraine is the result of a condition of neuronal hyperexcitability and the quest for drugs that are able to limit the number of crises justifies the attempt to utilise the new antiepileptic drugs in the prophylaxis of this pathology, which is so important due to its high prevalence and due to the high disability it causes. The study was randomised double-blind versus placebo, lasting 16 weeks, and was preceded by a run-in period of 4 weeks. One hundred and fifteen patients were randomly allocated to treatment with topiramate (TPM) or placebo: 35 patients completed the study in the TPM group and 37 patients in the placebo group. At the end of the double-blind phase of study, in the TPM group, we recorded a significant reduction in the frequency of migraine crises (from 5.26 at baseline to 2.60 in the last 4 weeks), a significant reduction in the quantity of symptomatic drugs taken as compared to the placebo control group (from 6.17+/-1.80 SD to 2.57+/-0.80) and a significant downward trend in the number of days of disability over the 16-week period of therapy. In the TPM group, side effects were transient and well tolerated. TPM has thus proven its efficacy and tolerability in the prophylaxis of migraine.

Adult↗
PubMed2003

Mosaic mutations of the LIS1 gene cause subcortical band heterotopia.

BACKGROUND: Subcortical band heterotopia (SBH) is a neuronal migration disorder. DCX mutations are responsible for almost all familial cases, 80% of sporadic female cases, and 25% of sporadic male cases of SBH, and are associated with more severe gyral and migration abnormality over the anterior brain regions. Somatic mosaicism has previously been hypothesized in a patient with posteriorly predominant SBH and a mutation of the LIS1 gene, which is usually mutated in patients with severe lissencephaly. The authors identified mosaic mutations of LIS1 in two patients (Patients 1 and 2) with predominantly posterior SBH. METHODS: After ruling out DCX mutations, the authors performed sequencing of the LIS1 gene in lymphocyte DNA. Because sequence peaks in both patients were suggestive of mosaic mutations, they followed up with denaturing high-pressure liquid chromatography analysis on blood and hair root DNA and compared the areas of heteroduplex and homoduplex peaks. A third patient showing the same mutation as Patient 2 but with no evidence of mosaicism was used for comparing the phenotype of mosaic vs full mutation. RESULTS: The two patients with posterior SBH harbored a missense (Arg241Pro) and a nonsense (R8X) mosaic mutation of LIS1. The rate of mosaicism in Patient 1 was 18% in the blood and 21% in the hair roots, whereas in Patient 2 it was 24% and 31% in the same tissues. The patient with a full R8X mutation of LIS1 had severe lissencephaly. CONCLUSIONS: Subcortical band heterotopia can occur with mosaic mutations of the LIS1 gene. Mutation analysis of LIS1, using highly sensitive techniques such as denaturing high-pressure liquid chromatography, should be considered for patients with posteriorly predominant subcortical band heterotopia and pachygyria.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2003

Occupational head injury and subsequent glioma.

We report the case of a policeman who suffered a severe head injury to the right temporoparietal lobe while driving a police car. Four years later, the patient developed a neoplasm at the precise site of the meningocerebral scar. Histological examination confirmed a glioblastoma multiforme adjacent to the dural scar. Radiological documentation of the absence of tumor at the time of injury, exact localization of the neoplasm in the injured cerebral area, and latency of the cancer supported the hypothesis of a causal relationship with brain trauma. Physicians faced with brain neoplasms in adults should carefully investigate the patient's personal history of head trauma. When a relationship with occupational head injury is probable, reporting of suspect occupational illness is compelling.

Accidents, Occupational↗
PubMed2001

Mathematical modeling of carbon monoxide exposures from anesthetic breakdown: effect of subject size, hematocrit, fraction of inspired oxygen, and quantity of carbon monoxide.

BACKGROUND: Carbon monoxide (CO) is produced by reaction of isoflurane, enflurane, and desflurane in desiccated carbon dioxide absorbents. The inspiratory CO concentration depends on the dryness and identity of the absorbent and anesthetic. The adaptation of existing mathematical models to a rebreathing circuit allows identification of patient factors that predispose to more severe exposures, as identified by carboxyhemoglobin concentration. METHODS: From our companion study, the authors used quantitative in vitro CO production data for 60 min at 7.5% desflurane or 1.5% isoflurane at 1 l/min fresh gas flow. The carboxyhemoglobin concentration was calculated by iteratively solving the Coburn Forster Kane equation modified for a rebreathing system that incorporates the removal of CO by patient absorption. Demonstrating good fit of predicted carboxyhemoglobin concentrations to published data from animal and human exposures validated the model. Carboxyhemoglobin concentrations were predicted for exposures of various severity, patients of different sizes, hematocrit, and fraction of inspired oxygen. RESULTS: The calculated carboxyhemoglobin concentrations closely predicted the experimental results of other investigators, thereby validating the model. These equations indicate the severity of CO poisoning is inversely related to the hemoglobin quantity of a subject. Fraction of inspired oxygen had the greatest effect in patients of small size with low hematocrit values, where equilibrium and not the rate of uptake determined carboxyhemoglobin concentrations. CONCLUSION: This model predicts that patients with low hemoglobin quantities will have more severe CO exposures based on the attainment of a higher carboxyhemoglobin concentration. This includes patients of small size (pediatric population) and patients with anemia.

Anesthetics, Inhalation↗
PubMed1999

[Changes of serum biochemical parameters during hypothermia and hypoxia in rats].

OBJECTIVE: To study the effects of hypothermia and hypoxia on serum biochemical parameters. Method Acute hypobaric hypoxia experiment in cold environment was carried out in 48 healthy Wistar rats to observe changes of hepatic, cardiac and renal functions. RESULT: Hepatic, cardiac and renal functions changed non-prominently after acute hypoxia exposure under cold condition. Under hypoxic exposure of the same degree, serum lactic dehydrogenase(LDH), alanine transaminase(ALT), blood urea nitrogen (BUN) and creatinine (Cr) increased more significantly at 10 degrees C than those at 20 degrees C (P < 0.01) while creatine kinase (CK) decreased significantly at 10 degrees C than that at 20 degrees C. CONCLUSION: After acute hypoxia in cold environment, the changes in cardiac function did not simply equal to the changes by cold environment plus changes by acute hypoxia.

Alanine Transaminase↗
PubMed1998

Patients with allergic contact dermatitis to nickel and nonallergic individuals display different nickel-specific T cell responses. Evidence for the presence of effector CD8+ and regulatory CD4+ T cells.

To investigate the mechanisms underlying the expression of allergic contact dermatitis, we compared the characteristics of nickel (Ni)-specific T cell responses in 10 patients with allergic contact dermatitis to Ni and in 10 healthy, nonallergic individuals. CD4+ T cells purified from peripheral blood of both allergic and nonallergic subjects proliferated similarly to NiSO4 in vitro, with the responses mostly restricted to CD4+ CD45RO+ memory T cells. In contrast, Ni-specific CD8+ T cell responses were detected only in allergic patients. Limiting dilution assay confirmed a high frequency of Ni-specific CD4+ T cells in both individual categories, and of Ni-specific CD8+ T cells in allergic patients, but not in nonallergic persons. Ni-specific CD4+ T cell clones prepared from nonallergic subjects displayed lower interferon-gamma and higher interleukin-10 production compared with T cell clones from allergic patients. The T cell skin-homing receptor, cutaneous lymphocyte-associated antigen, was expressed on the large majority of specific CD4+ clones from both the groups. Finally, Ni-specific CD8+ clones prepared from patients also expressed the cutaneous lymphocyte-associated antigen receptor, and released high interferon-gamma and no interleukin-4. In aggregate, the results suggest that the presence of specific CD8+ T cells and a distinct pattern of cytokine release (e.g., an augmented production of interleukin-10) by CD4+ T cells can be important elements in determining whether a hapten induces allergy or a silent immune response.

Adult↗
PubMed1996

Post-traumatic malignant glioma. Report of a case.

Only a few cases reported in the literature fulfil the currently established criteria for accepting the traumatic origin of some intracranial tumors. A case of post-traumatic glioma is presented. Several years after sustaining a commotive left parietal trauma, our patient developed symptoms of intracranial tumor. Neuroimaging (CT and MRI) showed a large neoplasia in the left temporo-parietal-occipital region, and stereotactic biopsy revealed a mixed glioma in continuity with the scar resulting from the trauma.

Brain Injuries↗
PubMedDate not supplied

Gabapentin in the prophylaxis of migraine: a double-blind randomized placebo-controlled study.

OBJECTIVE: Gabapentin is an antiepileptic drug of new generation that increases brain GABA levels. We report the results of a three-month randomised double-blind placebo-controlled study on the effects of gabapentin in the prophylaxis of patients with migraine meeting the IHS criteria. PATIENTS AND METHODS: We treated 63 patients suffering from migraine with or without aura. Patients treated their attack at home using symptomatic drugs and clinical assessment was recorded on a diary. After a washout of 8 week from any other prophylactic treatment, all patients were treated with 1200 mg/day of gabapentin; this is our therapeutic plan: 400 mg/day from 1st to 3rd day, 800 mg/day from 4th to 6th day and 1200 mg/day from 7th day. RESULTS: No patients withdrew, gabapentin was well tolerated; adverse events (somnolence, dizziness, tremor, fatigue and ataxia) generally were transient and mild to moderate in severity and in 13 patients (27%) only occurred. At the end of treatment, in such case, we reported a significative reduction of frequency and intensity of migraine in 30 patients treated with gabapentin. DISCUSSION: Our observations indicate that gabapentin is well tolerated by patients and that reduces headache frequency and use of symptomatic drugs in both groups. Gabapentin shows to have an effective therapeutic action in the prophylactic treatment of migraine.

Acetates↗
PubMedDate not supplied

Antiepileptic drugs in migraine prophylaxis: state of the art.

Antiepileptic drugs have proven their efficacy in the prophylactic treatment of migraine. Our study comprises a clinical trial that examines the efficacy of gabapentin and topiramate and a description of the pharmacologic characteristics and the efficacy of tiagabine, lamotrigine, levetiracetam and zonisamide. Antiepileptic drugs have multiple modes of action which can explain their efficacy in reducing neuronal excitability which is proven in epilepsy and postulated in migraine. The relationship between epilepsy and migraine has, in fact, been much debated but never convincingly proven. Antiepileptic drugs could be useful in migraine prophylaxis as some of these have determined a reduction in the monthly frequency and intensity of crises in subjects suffering from migraine with and without aura. These are the aims that have been proposed by the U.S. Headache Consortium Evidence-Based Guidelines. Further double-blind placebo-controlled studies are necessary in order to assess their safety and efficacy.

Acetates↗