Biomedical subjects

L Serra

Publications and source records attributed to L Serra.

At least 19 recordsLinked to original sources

PubMed2005

Priming for novel between-word associations in patients with organic amnesia.

Ten amnesic patients of various etiologies and 10 matched normal controls participated in this study. On 2 consecutive days, subjects studied 30 novel word-word associations 6 times. Using a cued recall task, we assessed episodic learning and delayed retention of the study material immediately after each study phase and again 24 hr after the final study phase. Further, we evaluated implicit memory for new between-word associations by means of an automatic relational priming paradigm immediately after the delayed cued recall trial. Amnesic patients performed poorly on the cued recall task. Moreover, in the overall group of amnesics the priming effect failed to reach statistical significance. When the overall group of amnesics was split according to mean performance on the cued recall task, those in the low performer subgroup--comprised of 6 patients with direct or indirect involvement of the hippocampi--were particularly poor at episodically remembering the associations and did not reveal any relational priming. These data support the hypothesis of similar impairment of new episodic and implicit learning in amnesic patients and suggest that the hippocampus is crucial for both kinds of new learning.

Adult↗

PubMed2005

Characterization of memory profile in subjects with amnestic mild cognitive impairment.

Different aspects of episodic long-term, short-term and implicit long-term memory were investigated in subjects who strictly fulfilled the criteria for the amnestic form of Mild Cognitive Impairment (a-MCI). Results showed normal short-term memory abilities in these subjects, while each of the episodic long-term memory indices explored showed poorer results in a-MCI subjects with respect to normal controls. Although some episodic memory functions were relatively well preserved, others appeared to have deteriorated to a level comparable to that of mild AD patients. The finding of an extensive impairment of all memory functions depending on hippocampal structures in a population with a high risk of developing dementia is strongly supportive of the hypothesis that a pure amnesic syndrome characterizes the preclinical phase of AD.

Activities of Daily Living↗

PubMed2004

Swift laboratory thermal evolution of wing shape (but not size) in Drosophila subobscura and its relationship with chromosomal inversion polymorphism.

Latitudinal clinal variation in wing size and shape has evolved in North American populations of Drosophila subobscura within about 20 years since colonization. While the size cline is consistent to that found in original European populations (and globally in other Drosophila species), different parts of the wing have evolved on the two continents. This clearly suggests that 'chance and necessity' are simultaneously playing their roles in the process of adaptation. We report here rapid and consistent thermal evolution of wing shape (but not size) that apparently is at odds with that suggestion. Three replicated populations of D. subobscura derived from an outbred stock at Puerto Montt (Chile) were kept at each of three temperatures (13, 18 and 22 degrees C) for 1 year and have diverged for 27 generations at most. We used the methods of geometric morphometrics to study wing shape variation in both females and males from the thermal stocks, and rates of genetic divergence for wing shape were found to be as fast or even faster than those previously estimated for wing size on a continental scale. These shape changes did not follow a neat linear trend with temperature, and are associated with localized shifts of particular landmarks with some differences between sexes. Wing shape variables were found to differ in response to male genetic constitution for polymorphic chromosomal inversions, which strongly suggests that changes in gene arrangement frequencies as a response to temperature underlie the correlated changes in wing shape because of gene-inversion linkage disequilibria. In fact, we also suggest that the shape cline in North America likely predated the size cline and is consistent with the quite different evolutionary rates between inversion and size clines. These findings cast strong doubts on the supposed 'unpredictability' of the geographical cline for wing traits in D. subobscura North American colonizing populations.

Analysis of Variance↗

PubMed2003

Endoscopic release in carpal tunnel syndrome: analysis of clinical results in 200 cases.

Carpal tunnel syndrome is the most common peripheral neuropathy. Conventional carpal tunnel surgery has been performed as a primary procedure for the decompression of the median nerve at the wrist in patients who have idiopathic carpal tunnel syndrome. While the results have been excellent, this surgical procedure has been reported to be related to high postoperative morbidity and extended length of recovery time. Over the past decade, endoscopic release of the transverse carpal ligament has been developed as a new, alternative method to the open procedures. Endoscopic carpal tunnel release has been reported to ensure less postoperative morbidity, more rapid recovery of strength, with earlier return to work, reduced disability time and a better cosmetic result. The authors present a surgical series of 200 hands in 164 patients (36 bilaterals) with idiopathic carpal tunnel syndrome, who underwent a single-portal endoscopic carpal tunnel release (Agee technique), with regards to the clinical outcome and complications occurred after 4-months follow-up.

Adolescent↗

PubMed2002

Linkage disequilibria between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura.

The association between mtDNA haplotypes and chromosomal arrangements in a natural population of Drosophila subobscura from Calvia (Balearic Islands, Spain) was studied in order to search for linkage disequilibria, in an attempt to explain the populational dynamics of the mtDNA haplotypes of this species in nature. The presence of Wolbachia was not detected. Two main haplotypes (I and II) were found, as well as a series of less common ones. The Tajima D-test seemed to indicate some kind of seasonal population bottleneck. An analysis of linkage disequilibrium and factorial analysis of correspondences detected an association between haplotype I and the J(ST) inversion and haplotype II and the J(1) inversion.

Animals↗

PubMed2002

Ancient schwannoma arising in a lymph node: report of a case and review of the literature.

We report a case of an intranodal schwannoma in a 79-year-old woman. The patient underwent a left colectomy for a colonic adenocarcinoma, with regional lymph node dissection. Macroscopic examination of the specimen revealed a well-circumscribed 4 cm nodule located in the pericolic fat. Macroscopically, it was interpreted as a metastatic lymph node. Microscopically, the nodule was composed of a proliferation of bland spindle cells, was immunohistochemically positive for S100 protein, and negative for smooth muscle actin, desmin, and cytokeratin. The pathological findings led to the diagnosis of a very rare case of primary schwannoma of the lymph node.

Abdomen↗

PubMed2001

Colonization of America by Drosophila subobscura: heterotic effect of chromosomal arrangements revealed by the persistence of lethal genes.

About 20 years ago Drosophila subobscura, a native Palearctic species, colonized both North and South America. In Palearctic populations lethal genes are not associated in general with particular chromosomal arrangements. In colonizing populations they are not randomly distributed and usually are associated to a different degree with chromosomal arrangements caused by the founder event. The persistence of two lethal genes in the colonizing populations, one completely associated with the O(5) inversion and the other partially associated with the O(3+4+7) arrangement, has been analyzed. In all populations studied (five North American and six South American) the observed frequency of the lethal gene completely associated with the O(5) inversion is higher than expected, the difference being statistically significant in all South American and one North American populations. The observed frequency of the lethal gene partially associated with the O(3+4+7) arrangement is also significantly higher than expected. Taking into account that the O(5) inversion exhibits significant latitudinal clines both in North and South America, an overdominant model favoring the heterokaryotypes seems to be in operation. From this model, a polynomial expression has been developed that allows us to estimate the relative fitness and the coefficient of selection against all karyotypes not carrying the O(5) inversion. The relative fitness of the O(5) heterokaryotypes is higher in South American than in North American populations. Furthermore, the observed frequencies of the lethal genes studied are in general very close to those of the equilibrium. This case is an outstanding demonstration in nature of an heterotic effect of chromosomal segments associated with lethal genes on a large geographic scale.

Animals↗

PubMed2001

Microsatellite variation in colonizing and palearctic populations of Drosophila subobscura.

The recent colonization of North America by Drosophila subobscura has provided a great opportunity to analyze a colonization process from the beginning. A comparative study using 10 microsatellite loci was conducted for five European and two North American populations. No genetic differentiation between European populations was detected, indicating that gene flow is high among them and that the microsatellites used in the present work represent neutral markers not subject to differentiation due to selection. Extensive reduction in the number of alleles and a significant decrease in heterozygosity in colonizing populations were detected that could be explained by the founder effect and a subsequent quick but not infinite expansion. Assuming that all alleles present in the colonized area were carried by the sample of colonizers, we estimated that most probably 4-11 individuals expanded in the new area. F(ST) and the chord distance measures reflect the colonization process more accurately, since drift has been the major force in differentiating the Old and New World populations, and thus other measures considering allele size differences, such as Rho(ST) and deltamu2, are less reliable for studying nonequilibrium populations. Finally, our results were consistent with the two-phase microsatellite mutational model, indicating that most alleles are generated by gain or loss of a repeat unit, while some alleles originate by more complex mutations.

Alleles↗

PubMed2001

[Extrarenal retroperitoneal angiomyolipoma: description of a case and review of the literature].

A case of retroperitoneal extrarenal angiomyolipoma is described. The patient, a 61-year-old woman, presented with a large retroperitoneal lipomatous mass. Histologically, it consisted of lipomatous tissue. Focally, there was interstitial and perivascular proliferation of bland oval and epithelioid cells with a large, eosinophilic or clear cytoplasm. Immunohistochemically, these elements were positive for smooth muscle actin and HMB-45. The literature on retroperitoneal extrarenal angiomyolipoma is briefly reviewed. It is important that the pathologist recognize this lesion, even when it is located in the retroperitoneum outside the kidney, and differentiate it from a liposarcoma.

Abdominal Pain↗

PubMed2001

Rapid evolution of wing size clines in Drosophila subobscura.

Parallel latitudinal clines across species and continents provide dramatic evidence of the efficacy of natural selection, however little is known about the dynamics involved in cline formation. For example, several drosophilids and other ectotherms increase in body and wing size at higher latitudes. Here we compare evolution in an ancestral European and a recently introduced (North America) cline in wing size and shape in Drosophila subobscura. We show that clinal variation in wing size, spanning more than 15 degrees of latitude, has evolved in less than two decades. In females from Europe and North America, the clines are statistically indistinguishable however the cline for North American males is significantly shallower than that for European males. We document that while overall patterns of wing size are similar on two continents, the European cline is obtained largely through changing the proximal portion of the wing, whereas the North American cline is largely in the distal portion. We use data from sites collected in 1986/1988 (Pegueroles et al. 1995) and our 1997 collections to compare synchronic (divergence between contemporary populations that share a common ancestor) and allochronic (changes over time within a population) estimates of the rates of evolution. We find that, for these populations, allochronically estimated evolutionary rates within a single population are over 0.02 haldanes (2800 darwins), a value similar in magnitude to the synchronic estimates from the extremes of the cline. This paper represents an expanded analysis of data partially presented in Huey et al. (2000).

Animals↗

PubMed2000

Rapid evolution of a geographic cline in size in an introduced fly.

The introduction and rapid spread of Drosophila subobscura in the New World two decades ago provide an opportunity to determine the predictability and rate of evolution of a geographic cline. In ancestral Old World populations, wing length increases clinally with latitude. In North American populations, no wing length cline was detected one decade after the introduction. After two decades, however, a cline has evolved and largely converged on the ancestral cline. The rate of morphological evolution on a continental scale is very fast, relative even to rates measured within local populations. Nevertheless, different wing sections dominate the New versus Old World clines. Thus, the evolution of geographic variation in wing length has been predictable, but the means by which the cline is achieved is contingent.

Animals↗

PubMed2000

Colonization of America by Drosophila subobscura: spatial and temporal lethal-gene allelism.

About twenty years ago Drosophila subobscura, a western Palearctic species, colonized both North and South America. Lethal genes in the O chromosome has been subject to much research. Lethal gene allelisms between American populations far away have been studied. These allelisms were not negligible, but all cases were due to the lethal gene completely associated to the O5 chromosomal inversion. Here we analyze the lethal genes in a new American population of D. subobscura (Centralia, Washington), located fairly close to a previously studied population (Bellingham, Washington) and separated in space and time with other American populations (Gilroy I and II in California and Santiago de Chile). The frequencies of lethal and semilethal genes of Centralia were 16.9+/-4.6 and 6.2+/-3.0, respectively. The intrapopulational allelism of Centralia was 0.122+/-0.036. Interpopulational allelisms were studied using the lethal genes from the populations separated in space and time from Centralia. The interpopulational allelisms between Centralia and Gilroy I (California) and between Centralia and Bellingham (Washington) were higher than the intrapopulational allelism (0.155+/-0.032 and 0.153+/-0.024, respectively). In all these cases allelism was due to a complete association between a lethal gene and the O5 chromosomal inversion. Accordingly, no other lethal genes are shared in these populations.

Alleles↗

PubMed2000

Planning and simulation of neurosurgery in a virtual reality environment.

OBJECTIVE: To report our experience with preoperative neurosurgical planning in our stereoscopic virtual reality environment for 21 patients with intra- and extra-axial brain tumors and vascular malformations. METHODS: A neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization and Navigation) was developed for the Dextroscope, a virtual reality environment in which the operator reaches with both hands behind a mirror into a computer-generated stereoscopic three-dimensional (3-D) object and moves and manipulates the object in real time with natural 3-D hand movements. Patient-specific data sets from multiple imaging techniques (magnetic resonance imaging, magnetic resonance angiography, magnetic resonance venography, and computed tomography) were coregistered, fused, and displayed as a stereoscopic 3-D object. A suite of 3-D tools accessible inside the VIVIAN workspace enabled users to coregister data, perform segmentation, obtain measurements, and simulate intraoperative viewpoints and the removal of bone and soft tissue. RESULTS: VIVIAN was used to plan neurosurgical procedures primarily in difficult-to-access areas, such as the cranial base and the deep brain. The intraoperative and virtual reality 3-D scenarios correlated well. The VIVIAN system substantially contributed to surgical planning by 1) providing a quick and better understanding of intracranial anatomic and abnormal spatial relationships, 2) simulating the craniotomy and the required cranial base bone work, and 3) simulating intraoperative views. CONCLUSION: The VIVIAN system allows users to work with complex imaging data in a fast, comprehensive, and intuitive manner. The 3-D interaction of this virtual reality environment is essential to the efficient assembly of surgically relevant spatial information from the data derived from multiple imaging techniques. The usefulness of the system is highly dependent on the accurate coregistration of the data and the real-time speed of the interaction.

Adult↗

PubMed1999

Rising melanoma incidence in an Italian community from 1986 to 1997.

We examined the incidence of primary invasive melanoma in the municipality of Reggio Emilia, northern Italy, in the period from 1986 to 1997. We identified 169 cases, five of which were intraocular. After adjustment for confounders, the risk of having a thick melanoma (Breslow > or = 1 mm) did not decrease over time, except in older females. The age-standardized incidence of cutaneous melanoma during the entire study period was 7.57 in males and 11 in females; from 1986-1991 to 1992-1997, it rose from 5.04 to 10.04 cases/100,000 person-years in males and from 8.96 to 13.09 cases/100,000 person-years in females. In males, the increase in incidence was almost entirely confined to subjects aged 30 or more, suggesting a possible cohort effect. We noted rising age-standardized incidences over time both in males with thin tumours (Breslow < 1 mm) (from 2.05 to 4.38 cases/100,000 person-years) and thick tumours (from 2.73 to 5.51 cases/100,000 person-years), while in females the increase was limited to thin melanomas (from 3.14 to 6.93 cases/100,000 person-years), mainly due to an increase in the older age groups (50 69 years and > or =70 years). The increase in thick melanomas among males and the expected cohort effects suggests antecedent exposure to environmental risk factors.

Adolescent↗

PubMed1999

[Acetaminophen hepatotoxicity in an alcohol addicted student. Case report].

We report a 12 years old male with a history of excessive alcohol intake, that developed a severe liver failure after the use of acetaminophen in therapeutic doses. He presented with encephalopathy, jaundice, fever and an upper gastrointestinal bleeding. Serum aspartate aminotransferase values were 5,250 IU/L. The patient received supportive care and oral corticosteroids, remained severely compromised for 72 hours and had a good evolution thereafter. The association of acetaminophen use and excessive alcohol intake in a patient who developed an acute hepatic failure and the absence of serological evidence of hepatitis A or B viral infection, support the diagnosis of drug induced liver failure.

Acetaminophen↗

PubMed1999

Planning of skull base surgery in the virtual workbench: clinical experiences.

Based on the KRDL Virtual Workbench, we present a neurosurgical planning system called VIVIAN (Virtual Intracranial Visualization And Navigation). This VR environment allows for fast and intuitive interaction with three-dimensional multimodal (MRI, MRA, MRV, CT) patient specific data-sets. The user reaches behind a mirror into a 3D workspace where the 3D data is surrounded by interactive virtual tools-racks. Tumors, blood vessels, cranial nerves and surgically relevant parts of the brain are segmented by interactive control of density transfer-functions or by manual outlining and tracing tools. A neurosurgical procedure is planned by using various visualization and measurement tools and the system allows for the simulation of bone drilling and tissue removal. We have planned 16 cases which required tumor surgery at the cranial base. VIVIAN provided an efficient and comprehensive way to understand pre-operatively the complexity of anatomical and pathological relationships. The ideal craniotomy and the extent of the required skull base exposure could be specified accurately.

Computer Simulation↗

PubMed1999

An interface for precise and comfortable 3D work with volumetric medical datasets.

We have developed a 3D/2D paradigm of interaction that combines manipulation of precise 3D volumetric data with unambiguous widget interaction. Precise 3D interaction is ensured by a combination of resting the lower arms on an armrest and pivoting the hands around the wrist. Unambiguous 2D interaction is achieved by providing passive haptic feedback by means of a virtual control panel whose position coincides with the physical surfaces encasing the system. We have tested this interface with a neurosurgical planning application that has been clinically used for 17 skull-base cases at two local hospitals.

Computer Simulation↗

PubMed1998

Plasmodium vivax congenital malaria in a newborn of a Zairian immigrant.

We report a case of congenital malaria in a newborn whose mother is a native of Zaire now living in Italy. The baby developed remittent fever in the 3rd week of life with anaemia and hepatosplenomegaly. Malaria parasites found in blood smears and erroneously diagnosed initially as Plasmodium falciparum were subsequently recognized as Plasmodium vivax. On the basis of the first diagnosis, treatment with quinine chlorhydrate was successfully undertaken without significant side-effects. P. vivax parasites were also recovered a posteriori in blood smears of the mother who was febrile during the week of her delivery. This report suggests that symptomatic congenital malaria may be more common than is generally thought and should be suspected in non-malarious countries in febrile newborns born to mothers who have travelled in or immigrated from malaria-endemic areas.

Animals↗