Visual evoked potentials in succinate semialdehyde dehydrogenase (SSADH) deficiency.

In mammals, increased GABA in the central nervous system has been associated with abnormalities of visual evoked potentials (VEPs), predominantly manifested as increased latency of the major positive component P100. Accordingly, we hypothesized that patients with a defect in GABA metabolism, succinate semialdehyde dehydrogenase (SSADH) deficiency (in whom supraphysiological levels of GABA accumulate), would manifest VEP anomalies. We evaluated VEPs on two patients with confirmed SSADH deficiency. Whereas the P100 latencies and amplitudes for binocular VEP analyses were within normal ranges for both patients, the P100 latencies were markedly delayed for left eye (OS) (and right eye (OD), patient 1) and monocular OS (patient 2): 134-147 ms; normal <118 ms. We hypothesize that elevated GABA in ocular tissue of SSADH patients leads to a use-dependent downregulation of the major GABAergic receptor in eye, GABA(C), and that the VEP recordings' abnormalities, as evidenced by P100 latency and/or amplitude measurements, may be reflective of abnormalities within visual systems. This is a preliminary finding that may suggest the utility of performing VEP analysis in a larger sample of SSADH-deficient patients, and encourage a neurophysiological assessment of GABA(C) receptor function in Aldh5a1(-/-) mice to reveal new pathophysiological mechanisms of this rare disorder of GABA degradation.

Combining spectroscopic techniques and chemometrics for the interpretation of lichen biomonitoring of air pollution.

A screening evaluation of lichen thalli, based on spectroscopic techniques coupled with chemometrics, is proposed as fast, simple and "green" method for the biomonitoring of air pollution. For two consecutive years, lichen thalli of Pseudevernia furfuracea were exposed for three months in selected sites of Liguria (NW-Italy) according to different levels and types of air pollution. At the end of the exposure period, transplanted thalli were analyzed by a set of monitoring techniques, including Front-Face Fluorescence Spectroscopy (FFFS), Near Infrared Spectroscopy (NIRS) and Plant Efficiency Analyser (PEA). Data were compared with values of air pollutants recorded during the exposure period by the Regional Agency for Environmental Protection, in order to relate lichen physiological indicators with the effects of atmospheric concentrations. A chemometric evaluation of the analytical signals, including principal component analysis (PCA) and quadratic discriminant analysis (QDA), was performed; the mean prediction rate of the discriminant models calculated on the FFFS emission spectra ranged from 70 to 75% on the external test sets. Front-face fluorescence spectroscopy proved to be a promising technique for the determination of level and type of pollutants in lichen thalli.

Charge patch attraction and reentrant condensation in DNA-liposome complexes.

We investigated the formation of complexes between cationic liposomes built up by DOTAP and three linear anionic polyions, with different charge density and flexibility, such as a single-stranded ssDNA, a double-stranded dsDNA and the polyacrylate sodium salt [NaPAA] of three different molecular weights. Our aim is to gain further insight into the formation mechanism of polyion-liposome aggregates of different sizes (lipoplexes), by comparing the behavior of DNA with a model polyelectrolyte, such as NaPAA, with approximately the same charge density but with a higher flexibility. We employed dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements, in order to explore both the hydrodynamic and structural properties of the aggregates resulting from polyion-liposome interaction and to present a comprehensive picture of the complexation process. The phenomenology can be summarized in a charge ratio-dependent scenario, where the main feature is the formation of large equilibrium clusters due to the aggregation of intact polyion-coated vesicles. At increasing polyion-liposome ratio, the size of the clusters continuously increases, reaching a maximum at a well-defined value of this ratio, and then decreases ("reentrant" condensation). The aggregation mechanism and the role of the polyion charge density in the complex formation are discussed in the light of the recent theories on the correlated adsorption of polyelectrolytes at charged interfaces. Within this framework, the phenomena of charge inversion and the reentrant condensation, peaked at the isoelectric point, finds a simple explanation.

Succinic semialdehyde dehydrogenase deficiency (SSADHD): Pathophysiological complexity and multifactorial trait associations in a rare monogenic disorder of GABA metabolism.

Discovered some 35 years ago, succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a rare, autosomal recessively-inherited defect in the second step of the GABA degradative pathway. Some 200 patients have been reported, with broad phenotypic and genotypic heterogeneity. SSADHD represents an unusual neurometabolic disorder in which two neuromodulatory agents, GABA (and the GABA analogue, 4-hydroxybutyrate), accumulate to supraphysiological levels. The unexpected occurrence of epilepsy in several patients is counterintuitive in view of the hyperGABAergic state, in which sedation might be expected. However, the epileptic status of some patients is most likely represented by broader imbalances of GABAergic and glutamatergic neurotransmission. Cumulative research encompassing decades of basic and clinical study of SSADHD reveal a monogenic disease with broad pathophysiological and clinical phenotypes. Numerous metabolic perturbations unmasked in SSADHD include alterations in oxidative stress parameters, dysregulation of autophagy and mitophagy, dysregulation of both inhibitory and excitatory neurotransmitters and gene expression, and unique subsets of SNP alterations of the SSADH gene (so-called ALDH5A1, or aldehyde dehydrogenase 5A1 gene) on the 6p22 chromosomal arm. While seemingly difficult to collate and interpret, these anomalies have continued to open novel pathways for pharmacotherapeutic considerations. Here, we present an update on selected aspects of SSADHD, the ALDH5A1 gene, and future avenues for research on this rare disorder of GABA metabolism.

The geographic distribution of human Y chromosome variation.

We examined variation on the nonrecombining portion of the human Y chromosome to investigate human evolution during the last 200,000 years. The Y-specific polymorphic sites included the Y Alu insertional polymorphism or "YAP" element (DYS287), the poly(A) tail associated with the YAP element, three point mutations in close association with the YAP insertion site, an A-G polymorphic transition (DYS271), and a tetranucleotide microsatellite (DYS19). Global variation at the five bi-allelic sites (DYS271, DYS287, and the three point mutations) gave rise to five "YAP haplotypes" in 60 populations from Africa, Europe, Asia, Australasia, and the New World (n = 1500). Combining the multi-allelic variation at the microsatellite loci (poly(A) tail and DYS19) with the YAP haplotypes resulted in a total of 27 "combination haplotypes". All five of the YAP haplotypes and 21 of the 27 combination haplotypes were found in African populations, which had greater haplotype diversity than did populations from other geographical locations. Only subsets of the five YAP haplotypes were found outside of Africa. Patterns of observed variation were compatible with a variety of hypotheses, including multiple human migrations and range expansions.

Y-chromosome STR loci in Sardinia and continental Italy reveal islander-specific haplotypes.

Six Y-linked tetranucleotide microsatellites were typed in a sample of continental Italians and Sardinians. Significant differences in allele distributions were found between peninsular Italy and the island. Patterns of distinct allelic associations were evident in Sardinia and in the mainland. STR haplotypes in a subset of Sardinian chromosomes were monophyletically related and indicated that additions/deletions of a single tetranucleotide unit had to sequentially occur within a historical time-scale (about 9,000 years). Assumptions on both the time elapsed since the peopling of the island and the number of mutational events led us to estimate (by three different methods) a rate of 2.7-11 x 10(-4) mutations per generation per locus--at the upper end of the range of values reported in the literature.

Y chromosome analysis reveals a sharp genetic boundary in the Carpathian region.

Nine single nucleotide (SNP) or indel binary polymorphisms were used to determine the frequencies and phylogenetic relationships of 12 Y chromosomal haplogroups in 289 males from Romania and the Republic of Moldova. Our data indicated a low but not null rate of the homoplasic appearance of the DYZ3 (-) allelic state. All other markers confirmed the previously proposed phylogeny. Based on the affinities between populations in terms of haplogroup frequencies, this work identified the geographical region of the Carpathians as a break point in the gene geography of Eastern Central Europe, providing a finer definition of one of the possible sharp genetic changes between Western and Eastern Europe.

Non-random association between DNA markers and Huntington disease locus in the Italian population.

A group of Huntington disease (HD) families of Italian ancestry was analyzed for 11 RFLPs from genetic loci mapped in 4p16 and genetically linked to the HD gene. We found a statistically significant difference of allele distributions in HD vs normal chromosomes for loci D4S10, D4S127, and D4S43. This observation increases the number of loci in linkage disequilibrium with HD. However, the amount of disequilibrium does not allow either a finer localization of the HD gene or a substantial improvement in risk calculations.

Direct cardiac massage without major thoracotomy: feasibility and systemic blood flow.

BACKGROUND: Open-chest cardiac massage (OC-CM) provides higher blood pressure and flow than closed-chest compression and may improve the probability of successful resuscitation from cardiac arrest. Its clinical use has been limited by its requirement for a major thoracotomy. The present pilot study tested the technical feasibility of performing effective direct cardiac massage without a major thoracic incision, by using a simple, manually-powered plunger-like device, inserted through a small thoracic incision, to cyclically compress the cardiac ventricles. The method was termed minimally-invasive direct cardiac massage (MID-CM). Systemic blood flow using MID-CM was compared to that with OC-CM, by both direct systemic hemodynamic measurements, cumulative metabolic indicators of the ratio of whole body oxygen delivery and oxygen consumption, and a metabolic index of pulmonary blood flow. METHODS: In 12 large swine, baseline systemic and pulmonary hemodynamic measurements were performed. Arterial and mixed venous blood gases and metabolic indicators of systemic blood flow were measured. Ventricular fibrillation was induced and after 4 min, animals underwent either bimanual OC-CM (N = 6) or MID-CM (N = 6). At 10, 20 and 30 min, hemodynamic and metabolic measurements were repeated. RESULTS: Systemic Blood Pressure: Aortic systolic and diastolic blood pressures were reduced from baseline levels with both OC-CM and MID-CM. No difference in pressure was noted between OC-CM and MID-CM groups. Pulmonary Artery Pressure: Pulmonary artery systolic pressure was elevated from baseline during OC-CM and MID-CM. Pulmonary artery diastolic pressures remained constant throughout the resuscitation period in both groups. No differences in pulmonary systolic or diastolic pressure were noted between OC-CM and MID-CM groups. A trend towards higher pulmonary systolic pressures appeared with MID-CM. Thermodilution Blood Flow: Cardiac index fell from baseline levels with OC-CM and MID-CM. No difference in cardiac index was noted between OC-CM and MID-CM groups. Metabolic Indices: Mixed venous O2 saturation decreased from baseline levels during resuscitation in both experimental groups, with a further decrease at 30 min compared to 10- and 20-min levels. No difference was noted between OC-CM and MID-CM groups at any point. Arterial pH was reduced from baseline levels at 30 min in both groups compared to baseline but no difference was noted between groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Open-chest cardiac massage without major thoracotomy: metabolic indicators of coronary and cerebral perfusion.

OBJECTIVE: To compare the coronary and cerebral perfusion achieved using a novel method of minimally-invasive, direct cardiac massage to that obtained using bimanual, open-chest cardiac massage. DESIGN: Prospective, controlled animal study with repeated measures. SETTING: University research laboratory. SUBJECTS: Large domestic swine. INTERVENTIONS: Aortic, coronary sinus, jugular venous and pulmonary artery catheters were placed. Following an equilibration period, ventricular fibrillation was induced. After 4 min of untreated ventricular fibrillation, animals underwent bimanual, open-chest cardiac massage (N = 6) or minimally-invasive, direct cardiac massage using a novel device for direct cardiac compression (N = 6). Adrenaline was administered at a dose of 1 mg intravenously every 5 min. MEASUREMENTS: Systemic metabolic parameters, (arterial PO2, PCO2 and lactate concentration) and coronary sinus and jugular venous metabolic parameters (pH, PVO2, SVO2, PVCO2 and lactate concentration) were measured and calculated (coronary sinus/jugular-arterial SVO2, coronary sinus/jugular-arterial PCO2 and lactate differences) at baseline and at 10, 20 and 30 min following induction of ventricular fibrillation. Animals were euthanised after 30 min with no attempt at defibrillation. MAIN RESULTS: Oxygen tension and oxygen saturation of coronary sinus blood declined significantly during the experimental period, but no differences were noted between treatment groups. The coronary sinus-arterial oxygen saturation difference increased during the study with no significant differences between groups. Coronary sinus PCO2 and the coronary sinus-arterial PCO2 difference increased significantly in both experimental groups during cardiac massage. No inter-group differences were noted. A similar relationship was noted in coronary sinus lactate values. The coronary sinus-arterial lactate difference displayed a positive balance at all intervals with no differences noted between group values. The oxygen tension and oxygen saturation of jugular venous blood, were reduced from baseline levels with both treatments. The jugular-arterial oxygen saturation difference increased in both groups compared to baseline values. Between group values were significantly different only at the 20 min interval. Both the jugular venous PCO2 and the jugular-arterial PCO2 gradient were elevated at all intervals, but no inter-group differences were noted. Jugular venous lactate concentration rose steadily with time in both groups. No significant increase in the jugular-arterial lactate gradient was noted at any time point. CONCLUSIONS: Minimally-invasive, direct cardiac massage provides coronary and cerebral perfusion similar to that achieved using standard open-chest cardiac massage. This method may provide a more effective substitute for standard, closed-chest cardiac massage in cases of refractory cardiac arrest.

Extended intravascular shunting in an experimental model of vascular injury.

PURPOSE: To examine the extended patency (> 24 hrs) of heparin-bonded intravascular shunts in a porcine model of vascular injury. PROCEDURES: Adult swine underwent bilateral, common iliac artery resection (n = 5) or bilateral common iliac vein resection (n = 5) and vessel replacement with interposition, heparin-bonded shunts. Three control swine had vessel dissection only. Hematologic and coagulation profiles were measured at baseline and 24 hrs. Limb perfusion was assessed at 24 hrs by clinical exam and angiography. RESULTS: At 24 hrs, all limbs in both shunt groups were well perfused. All arterial shunts were angiographically patent. No distal emboli were detected. Nine of 10 venous shunts were patent, seven were lined with non-occluding thrombus. No alterations in hematologic or coagulation profiles were noted. CONCLUSIONS: Heparin-bonded shunts remained patent in arteries for 24 hours. Shunts placed in the venous system were prone to thrombus formation but most remained patent.

Y-chromosomal variation in the Czech Republic.

To analyze the contribution of the Czech population to the Y-chromosome diversity landscape of Europe and to reconstruct past demographic events, we typed 257 males from five locations for 21 UEPs. Moreover, 141 carriers of the three most common haplogroups were typed for 10 microsatellites and coalescent analyses applied. Sixteen Hg's characterized by derived alleles were identified, the most common being R1a-SRY(10831) and P-DYS257*(xR1a). The pool of haplogroups within I-M170 represented the third most common clade. Overall, the degree of population structure was low. The ages for Hg I-M170, P-DYS257*(xR1a), and R1a-SRY(10831) ap peared to be comparable and compatible with their presence during or soon after the LGM. A signal of population growth beginning in the first millennium B.C. was detected. Its similarity among the three most common Hg's indicated that growth was characteristic for a gene pool that already contained all of them. The Czech population appears to be influenced, to a very moderate extent, by genetic inputs from outside Europe in the post-Neolithic and historical times. Population growth postdated the archaeologically documented introduction of Neolithic technology and the estimated central value coincides with a period of repeated changes driven by the development of metal technologies and the associated social and trade organization.

Population structure in the Mediterranean basin: a Y chromosome perspective.

The Mediterranean region has been characterised by a number of pre-historical and historical demographic events whose legacy on the current genetic landscape is still a matter of debate. In order to investigate the degree of population structure across the Mediterranean, we have investigated Y chromosome variation in a large dataset of Mediterranean populations, 11 of which are first described here. Our analyses identify four main clusters in the Mediterranean that can be labelled as North Africa, Arab, Central-East and West Mediterranean. In particular, Near Eastern samples tend to separate according to the presence of Arab Y chromosome lineages, suggesting that the Arab expansion played a major role in shaping the current genetic structuring within the Fertile Crescent.

Lactic acid enantiomers: separation by thin-layer chromatography on silica gel plates impregnated with Cu2+.

A simple and fast method for the separation of D- and L-lactic acid enantiomers by thin-layer chromatographic silica gel precoated plates impregnated with Cu(II) is proposed. The two lactic acid enantiomers, dissolved in acetone, are deposed on these plates. D- and L-lactic acids form complexes with Cu(II), with different Rf values, suitable for radiochemical measurements. The real separation was confirmed by enzymatic tests carried out on spots of D and L forms scraped from the chromatographic plates. Total radioactivity of 14C-labeled D- and L-lactic acids was recovered. A Cu/lactic acid complex is evidenced.

Colour blindness (CB) distribution in the male population of Albanian and Croatian communities of Molise, Italy (with a review of the published Caucasoid CB gene frequencies).

All the secondary school students of the Albanian and Croatian communities of Molise were tested for colour vision. Percent frequencies of red-green colour blindness were 5.91 +/- 1.73 and 7.02 +/- 3.38. These figures are in agreement with those found for Central Italy thus confirming the similarity of these communities with the rest of Italy as described for several other autosomal polymorphisms. The distribution of red-green CB genes in Europe shows that they are slightly more frequent in Northern Europe than in Southern Europe and Northern Africa.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency in southern Italy: a case of G6PD A(-) associated with favism.

During a routine screening for G6PD deficiency in the Province of Matera (Southern Italy), an eleven-year-old boy was brought to our attention who had fever obviously caused by a viral infection, but who also had hepatosplenomegaly and haemoglobinuria. The boy had previously experienced two severe haemolytic attacks. At the age of six months severe haemolysis occurred after the ingestion of cooked fava beans. At the age of seven years, the haemolytic episode was very likely triggered by oral administration of co-trimoxazole. The G6PD activity level in erythrocyte lysate was clearly defective (25% of normal). The electrophoretic mobility of G6PD was 110% of normal. These data together with those obtained from biochemical and molecular characterisation allowed the variant to be identified as G6PD A(-). This is the first report of an association between the African type G6PD deficiency variant and favism.