Performance of small-scale CHO perfusion cultures using an acoustic cell filtration device for cell retention: characterization of separation efficiency and impact of perfusion on product quality

Several small-scale Chinese hamster ovary (CHO) suspension cultures were grown in perfusion mode using a new acoustic filtration system. The separation performance was evaluated at different cell concentrations and perfusion rates for two different CHO cell lines. It was found that the separation performance depends inversely on the cell concentration and perfusion rate. High media flow rates as well as high cell concentrations resulted in a significant drop in the separation performance, which limited the maximal cell concentration achievable. However, packed cell volumes of 10% to 16% (corresponding to 3 to 6. 10(7) cells/mL) could be reached and were maintained without additional bleeding after shifting the temperature to 33 degrees C. Perfusion, up to 50 days, did not harm the cells and did not result in a loss of performance of the acoustic filter as often seen with other perfusion systems. Volumetric productivities in perfusion mode were 2- to 12-fold higher for two cell lines producing two different glycoproteins when compared to fed-batch or batch processes using the same cell lines. Product concentrations were in the range of 20% to 80% of batch or fed-batch culture, respectively. In addition, using the protease-sensitive product rhesus thrombopoietin, we could show that cultivation in perfusion mode drastically reduced proteolysis when compared to a batch culture without addition of protease inhibitors such as leupeptin.

Lineage-specific evolutionary rate in mammalian mtDNA

The existence of a lineage-specific nucleotide substitution rate in mammalian mtDNA has been investigated by analyzing the mtDNA of all available species, that is, 35 complete mitochondrial genomes from 14 mammalian orders. A detailed study of their evolutionary dynamics has been carried out on both ribosomal RNA and first and second codon positions (P12) of H-strand protein-coding genes by using two different types of relative-rate tests. Results are quite congruent between ribosomal and P12 sites. Significant rate variations have been observed among orders and among species of the same order. However, rate variation does not exceed 1.8-fold between the fastest (Proboscidea and Primates) and the slowest (Perissodactyla) evolving orders. Thus, the observed mitochondrial rate variations among taxa do not invalidate the suitability of mtDNA for drawing mammalian phylogeny. Dependence of evolutionary rate differences on variations in mutation and/or fixation rates was examined. Body size, generation time, and metabolic rate were tested, and no significant correlation was observed between them and the taxon-specific evolutionary rates, most likely because the latter might be influenced by multiple overlapping variable constraints.

[Extracapillary IgA nephropathy associated with infection with hepatitis C virus and hepatic cirrhosis]

We describe a 36 year old man who was admitted to the hospital with dyspnea, edema of the lower limbs, arterial hypertension and oliguric renal failure. He had microhematuria and nephrotic range proteinuria, immunological tests were normal or negative. Renal biopsy revealed global (55%) or segmental glomeruloesclerosis, remaining glomeruli showed extracapillary proliferation (25%). Immunofluorescence study disclosed IgA mesangial deposits. He was also diagnosed as having liver cirrhosis with positive serology against hepatitis C virus. He was treated with dialysis, antihypertensive drugs and steroids with improvement of the renal function. However, ten months later maintenance hemodialysis became necessary. We emphasize two points: first IgA glomerulonephritis is rarely associated with hepatitis C infection, and second crescentic IgA nephropathy has been infrequently reported in liver cirrhosis.

Three maize root-specific genes are not correctly expressed in regenerated caps in the absence of the quiescent center

The quiescent center is viewed as an architectural template in the root apical meristem of all angiosperm and gymnosperm root tips. In roots of Arabidopsis thaliana (L.) Heynh., the quiescent center inhibits differentiation of contacting initial cells and maintains the surrounding initial cells as stem cells. Here, the role of the quiescent center in the development of the maize (Zeca mays L.) root cap has been further explored. Three maize root-specific genes were identified. Two of these were exclusively expressed in the root cap and one of them encoded a GDP-mannose-4,6-dehydratase. Most likely these two genes are structural, tissue-specific markers of the cap. The third gene, a putative glycine-rich cell wall protein, was expressed in the cap and in the root epidermis and, conceivably is a positional marker of the cap. Microsurgical and molecular data indicate that the quiescent center and cap initials may regulate the positional and structural expression of these genes in the cap and thereby control root cap development.

The influence of temperature upon the hydrolysis of cellobiose by beta-1,4-glucosidases from Aspergillus niger

We have made experimental studies into the enzymatic hydrolysis of cellobiose within the temperature range of 40 degrees C to 70 degrees C at pH 4.9, by using beta-1,4-glucosidase from Aspergillus niger. At 70 degrees C there was significant enzyme deactivation, which could be fitted to a potential deactivation model with values of n equal to 1.09 and k(d) to 0.1564 (g/l)(-0.09) min(-1), whereas the rate of hydrolysis could be fitted to the Michaelis-Menten equation. Between 40 degrees C and 60 degrees C we noted a substrate inhibition and that the CEC compound formed contributed to glucose production. The apparent activation energies had values of 4.66, 8.45, 4.82, and 3.99 kJ/mol for the kinetic constants k(a) and k(a2) the Michaelis constant and the substrate inhibition constant, respectively.

Auditory event-related potentials in poor readers

Although poor readers (PR) are considered the major group among reading-disabled children, there are not event-related potentials (ERP) studies reported of PR on the subject. In this study, attentional and memory processes were studied in an auditory oddball task in PR and normal controls. ERP to auditory stimuli were recorded in 19 leads of the 10/20 system, using linked earlobes as references, in 20 normal children (10 female) and 20 PR (10 female) of the same age (10-12 years old). Two pure tones (1000 and 3000 Hz) were used in an oddball paradigm. No significant differences were observed in the amplitudes and latencies of N100 between the groups. However, N200 to frequent stimuli and P200 to both frequent and infrequent stimuli were of higher amplitude in poor readers than in normal children. There were no differences between groups in the latency and amplitude of P300. The results suggest that PR use more attentional resources in the components occurring before P300 to both frequent and infrequent stimuli than the normal children, and this finding is particularly marked for PR girls.

Separation of polyamines, conjugated to DNA, by reversed-phase high-performance liquid chromatography

Genomic DNA was isolated from the lichen Evernia prunastri in order to analyze by high-performance liquid chromatography the occurrence of polyamines conjugated to the macromolecule. The acid-insoluble (PH) fraction of this DNA contained mainly conjugated spermidine, although small amounts of free putrescine and spermidine were also present. The PH fraction of DNA also contained conjugated evernic acid, the main phenol produced by this lichen species. Conjugation of polyamines to calf thymus DNA was carried out under in vitro conditions. Conjugation was to spermidine and mainly to spermine and produced DNA compactation. Evernic acid enhanced the action of polyamines in order to produce DNA aggregation.

Primary task demands modulate P3a amplitude

Auditory event-related brain potentials (ERPs) were recorded from 10 subjects in two different conditions: (1) subjects were required to reorder five visually presented letters in order to form a word and provide a verbal response (task condition); (2) subjects were presented with a control stimulus with the same physical characteristics as the experimental stimulus, but containing just one type of letter (i.e., AAAAA). Subjects had to verbally respond to such stimuli by saying "A" (control condition). Tones of 1000 Hz (standard) and 1050 Hz (deviant) were also presented to the subjects in a 85%-15% probability paradigm 2 s before, during and 8 s after the presentation of the visual stimuli. Recordings were obtained from Fpz, Fz, Cz and Pz vs. linked ears. Auditory ERPs to the auditory stimuli after the presentation of the visual letter string and during the performance of the task were averaged for the standard and deviant tones in both conditions. Only correct responses were considered for the averages. The N100 was affected by stimulus type (standard vs. deviant) but not by condition (task vs. control); however, larger P3a waves were observed during the control than during the task condition. No significant differences between conditions were observed in the mismatch negativity (MMN) latency range. These results suggest that primary task demands modulate involuntary attention processing.

Evolutionary genomics in Metazoa: the mitochondrial DNA as a model system

One of the most important aspects of mitochondrial (mt) genome evolution in Metazoa is constancy of size and gene content of mtDNA, whose plasticity is maintained through a great variety of gene rearrangements probably mediated by tRNA genes. The trend of mtDNA to maintain the same genetic structure within a phylum (e.g., Chordata) is generally accepted, although more recent reports show that a considerable number of transpositions are observed also between closely related organisms. Base composition of mtDNA is extremely variable. Genome GC content is often low and, when it increases, the two complementary bases distribute asymmetrically, creating, particularly in vertebrates, a negative GC-skew. In mammals, we have found coding strand base composition and average degree of gene conservation to be related to the asymmetric replication mechanism of mtDNA. A quantitative measurement of mtDNA evolutionary rate has revealed that each of the various components has a different evolutionary rate. Non-synonymous rates are gene specific and fall in a range comparable to that of nuclear genes, whereas synonymous rates are about 22-fold higher in mt than in nuclear genes. tRNA genes are among the most conserved but, when compared to their nuclear counterparts, they evolve 100 times faster. Finally, we describe some molecular phylogenetic reconstructions which have produced unexpected outcomes, and might change our vision of the classification of living organisms.

Action of substance P (neurokinin-1) receptor activation on rat neostriatal projection neurons

Substance P (SP) acts as a neurotransmitter in the neostriatum through the axon collaterals of spiny projection neurons. However, possible direct or indirect actions of SP on the neostriatal output neurons have not been described. Targets of SP terminals within the neostriatum include interneurons, spiny neurons, afferent fibers and boutons. SP induces the release of both dopamine (DA) and acetylcholine (ACh). Since some postsynaptic actions of both DA and ACh on spiny neurons are known, we asked if activation of neostriatal NK1-class receptors is able to reproduce them. The SP NK1-receptor agonist, GR73632 (1 microM), had both excitatory and inhibitory actions on virtually all spiny neurons tested at resting potential. The excitatory action was blocked by atropine and coursed with an increase in firing rate and input resistance (R(N)). The inhibitory action was blocked by haloperidol and coursed with a reduction in firing rate and R(N). Therefore, the release of both DA and ACh induced by NK1-receptor activation modulates indirectly the excitability of the projection neurons. SP facilitates the actions of these transmitters on the spiny neuron. A residual excitatory response to the NK1-receptor agonist was observed in 30% of a sample of neurons tested in the presence of both haloperidol and atropine. The increase in R(N) that accompanied this response could be observed in the presence of 1 microM TTX or 100 microM Cd2+, suggesting a direct effect. Double labeling showed that only SP-immunoreactive neurons were facilitated by NK1-receptor activation in these conditions.

Developmental switch in the short-term modification of unitary EPSPs evoked in layer 2/3 and layer 5 pyramidal neurons of rat neocortex

Amplitudes of EPSPs evoked by repetitive presynaptic action potentials can either decrease (synaptic depression) or increase (synaptic facilitation). To determine whether facilitation and depression in the connections between neocortical pyramidal cells varied with the identity of the pre- or the postsynaptic cell and whether they changed during postnatal development, whole-cell voltage recordings were made simultaneously from two or three pyramidal cells in layers 2/3 and 5 of the rat sensorimotor cortex. Unitary EPSPs were evoked when pre- and postsynaptic neurons were in the same and in different layers. In young [postnatal day 14 (P14)] cortex, EPSPs evoked in all connected neurons depressed. The degree of depression was layer specific and was determined by the identity of the presynaptic cell. EPSPs evoked by stimulation of presynaptic layer 5 neurons depressed significantly more than did those evoked by stimulation of layer 2/3 neurons. In mature cortex (P28), however, the EPSPs evoked in these connected neurons facilitated to a comparable degree regardless of the layer in which pre- and postsynaptic neurons were located. The results suggest that in young cortex the degree of synaptic depression in connected pyramidal cells is determined primarily by whether the presynaptic cell was in layer 2/3 or 5 and that maturation of the cortex involves a developmental switch from depression to facilitation between P14 and P28 that eliminates the layer-specific differences. A functional consequence of this switch is that in mature cortex the spread of excitation between neocortical pyramidal neurons is enhanced when action potentials occur in bursts.

N400 and lexical decisions: automatic or controlled processing?

OBJECTIVE

To investigate whether the N400 effect is sensitive to automatic or controlled processes.

METHODS

Two experiments were performed. In one experiment, directly related word pairs were used. In the other experiment, mediated-related word pairs were used. In order to reduce controlled processes, each experiment consisted of 3 tasks: Low- and high-proportion of related pairs, and single presentation lexical decision task.

RESULTS

In the first experiment, the amount of priming was equivalent for the 3 tasks. The N400 effect appeared in the high and low proportion of directly related words, but not in the single presentation task. In the second experiment, behavioral priming was also found in the 3 tasks. However, the N400 effect was observed only in the task with low proportion of related pairs.

CONCLUSION

These results suggest that the N400 effect may be related to controlled processes.

Cholinergic modulation of neostriatal output: a functional antagonism between different types of muscarinic receptors

It is demonstrated that acetylcholine released from cholinergic interneurons modulates the excitability of neostriatal projection neurons. Physostigmine and neostigmine increase input resistance (RN) and enhance evoked discharge of spiny projection neurons in a manner similar to muscarine. Muscarinic RN increase occurs in the whole subthreshold voltage range (-100 to -45 mV), remains in the presence of TTX and Cd2+, and can be blocked by the relatively selective M1,4 muscarinic receptor antagonist pirenzepine but not by M2 or M3 selective antagonists. Cs+ occludes muscarinic effects at potentials more negative than -80 mV. A Na+ reduction in the bath occludes muscarinic effects at potentials more positive than -70 mV. Thus, muscarinic effects involve different ionic conductances: inward rectifying and cationic. The relatively selective M2 receptor antagonist AF-DX 116 does not block muscarinic effects on the projection neuron but, surprisingly, has the ability to mimic agonistic actions increasing RN and firing. Both effects are blocked by pirenzepine. HPLC measurements of acetylcholine demonstrate that AF-DX 116 but not pirenzepine greatly increases endogenous acetylcholine release in brain slices. Therefore, the effects of the M2 antagonist on the projection neurons were attributable to autoreceptor block on cholinergic interneurons. These experiments show distinct opposite functions of muscarinic M1- and M2-type receptors in neostriatal output, i.e., the firing of projection neurons. The results suggest that the use of more selective antimuscarinics may be more profitable for the treatment of motor deficits.

Broad band spectral EEG parameters correlated with different IQ measurements

The relationship of IQ (measured by WAIS and all its subscales) and EEG broad band spectral parameters were studied in 40 right-handed, male volunteers ranging in age from 20 to 25 years old. EEGs were recorded in 20 derivations during rest with eyes opened. The results obtained reveal positive and negative correlations with abundant frontal participation in all bands. Mean frequency data show a frequency shift in a very narrow range suggesting that more relations in narrow band could be achieved. These results highlight the need of psychological tests that measure more homogeneous abilities and finer measurement technique to reveal clearly explainable correlations and demonstrate that EEG recordings do reflect intellectual abilities.

Conversion of cardiac and liver transplant recipients from HPLC and FPIA (polyclonal) to an FPIA (monoclonal) technique for measurement of blood cyclosporin A

In an effort to replace HPLC and FPIA (polyclonal) for whole blood determination of Cyclosporin A (CsA), this study examined the application of FPIA (monoclonal) in patients post cardiac and liver transplantation. The assay had a minimum detectable dose of 15 microg/L, an overall recovery of 97% and was linear to 1200 microg/L, and gave inter-assay precision values of < 5% (CV). On comparing FPIA (monoclonal) and HPLC for 59 cardiac transplant recipient blood samples, a correlation of FPIA (monoclonal) = 1.30 (HPLC) + 36.34, r = 0.96 was obtained. With liver transplant samples (n = 348), the correlation was FPIA (monoclonal) = 1.21 (HPLC) + 42.15, r = 0.98. Correlation on 131 cardiac transplant recipients gave FPIA (monoclonal) = 0.31 FPIA (polyclonal) + 43.97, r = 0.68. It is concluded that when converting from HPLC to FPIA (monoclonal) a positive bias of 21%-30% is observed, and in replacing FPIA (polyclonal) with FPIA (monoclonal), a negative bias of 50%-69% is seen with liver and cardiac patients respectively. These data indicate that therapeutic ranges should be re-established or adjustments in CsA dosing would be necessary.

Changes in hypothalamic calmodulin concentration induced by perinatal hormone manipulation in the rat

Calmodulin (CaM) presence and concentration was determined (RIA) in the rat hypothalamus (2, 6, 12, 24 h and 90 days after birth) in vehicle-treated animal (controls), in testosterone propionate (TP)-treated females (30 microg/rat subcutaneously 1 h after birth) and in tamoxifen-treated males (200 microg/rat subcutaneously 1 h after birth). CaM concentration, either as total content/hypothalamus or as concentration per mg ww, was significantly higher in both male and female adult rats than in newborn subjects. CaM concentration/mg protein increased with age, being two times higher in adult males and greater than three times higher in adult females than in their respective newborns. Two, 12, and 24 h after birth CaM concentration was significantly lower in control females than in control males. This relation was reversed in adults in which CaM concentration was higher in females. The application of TP to the females and tamoxifen to the males, induced a significant decrease in CaM/mg protein, both in the newborn (2 and 6 h) and in the adult animals. In adults, treated females had CaM concentrations similar to those found in control males. Our data suggest: first, a lasting effect of newborn hormonal treatment upon the CaM concentration in rat hypothalamus; second, that CaM is preferentially synthesized in the adult female hypothalamus, indicating an important role of this protein in female reproductive function.

The triad of empowerment: leadership, environment, and professional traits

Empowerment is defined as "moving decision making down to the lowest level where competent decisions can be made." In the hospital setting, this would most commonly be at the point of direct patient care or staff nurse level; however, this kind of empowerment requires an environment of autonomy where mutual trust and respect are encouraged. The empowerment process requires that staff be prepared to accept and effectively use expanded decision-making responsibilities. The professional accountabilities of the empowered nurse include having a sense of value about their work and willingness to provide the full scope of practice as well as ability to work as equal members of a comprehensive interdisciplinary team. In order to move into a fully empowered position, professional nurses need mentoring, education, awareness of political activism opportunities, and networking skills.

Target-cell-specific facilitation and depression in neocortical circuits

In neocortical circuits, repetitively active neurons evoke unitary postsynaptic potentials (PSPs) whose peak amplitudes either increase (facilitate) or decrease (depress) progressively. To examine the basis for these different synaptic responses, we made simultaneous recordings from three classes of neurons in cortical layer 2/3. We induced repetitive action potentials in pyramidal cells and recorded the evoked unitary excitatory (E)PSPs in two classes of GABAergic neurons. We observed facilitation of EPSPs in bitufted GABAergic interneurons, many of which expressed somatostatin immunoreactivity. EPSPs recorded from multipolar interneurons, however, showed depression. Some of these neurons were immunopositive for parvalbumin. Unitary inhibitory (I)PSPs evoked by repetitive stimulation of a bitufted neuron also showed a less pronounced but significant difference between the two target neurons. Facilitation and depression involve presynaptic mechanisms, and because a single neuron can express both behaviors simultaneously, we infer that local differences in the molecular structure of presynaptic nerve terminals are induced by retrograde signals from different classes of target neurons. Because bitufted and multipolar neurons both formed reciprocal inhibitory connections with pyramidal cells, the results imply that the balance of activation between two recurrent inhibitory pathways in the neocortex depends on the frequency of action potentials in pyramidal cells.

Asymmetrical directional mutation pressure in the mitochondrial genome of mammals

The base composition of 25 complete mammalian mitochondrial (mt) genomes has been analyzed taking into account all three codon positions (P1230 and fourfold degenerate sites (P4FD) of H-strand genes. In the nontranscribed L strand, G is the less represented base and A is the most represented one in all cases, while C and T differ among species. H-strand protein-coding genes show an asymmetric distribution of the four bases between the two strands. The asymmetry indexes AT and GC skews on P4FD are much higher than those on P123, suggesting the existence of asymmetrical directional mutation pressure. Relationships between the compositional features and transcription of replication processes have been investigated in order to find a possible mechanism that could explain the origin of this asymmetry. AT and GC skews, the base composition in fourfold degenerate sites, and the number of variable sites for each gene are significantly correlated with the duration of single-stranded state of the H-stranded genes during replication. We tested different replication-related hypotheses, such as the existence of biased dNTP pools, gamma DNA polymerase mispairing, and the asymmetric replication itself. Most of them failed to explain the observed results, hydrolytic deaminations being the only one in agreement with our data. Thus, we hypothesize that one of the crucial processes for the origin of asymmetric and biased base composition of mammalian mitochondrial genomes is the spontaneous deamination of C and A in the H strand during replication.

Complete mitochondrial DNA sequence of the fat dormouse, Glis glis: further evidence of rodent paraphyly

The complete mitochondrial genome of the fat dormouse, Glis glis, has been sequenced (16,602 bp). A total of 23 complete mitochondrial mammalian genomes have been taken into account for phylogenetic reconstruction. Phylogenetic analyses were performed with parsimony, distance (stationary Markov model), and maximum-likelihood methods. In all cases, data strongly support the paraphyly of rodents, with dormouse and guinea pig in a different clade from rat and mouse, reaching bootstrap values of 95%. Rodent monophyly and the existence of Glires (Rodentia and Lagomorpha) are weakly supported, with maximum bootstrap values of 11% and 8.6%, respectively. This result agrees with the analyses of isochore patterns in the nuclear genome and the B2 and B2-like retroposons, which show a close relationship between dormice and guinea pigs rather than between dormice and rats and mice.

Passive properties of neostriatal neurons during potassium conductance blockade

Voltage recordings from neostriatal projection neurons were obtained using in vitro intracellular techniques before and during K+-conductance blockade. Neurons were stained with the biocytin technique. Somatic surface area (AS) was determined by both whole-cell recordings in isolated somata and by measuring stained somata recorded in slices. Dendritic measurements were done in reconstructed neurons. Average determinations of dendritic (AD) and neuronal (AN) surface areas coincided with previously reported anatomical data. Thus: As approximately 6.5 x 10(-6) cm2; AD approximately 1.9 x 10(-4) cm2; AN approximately AD + AS approximately 2 x 10(-4) cm2; AD/AS approximately 30. Measurements were done before and after superfusion with K+-conductance blockers (K+-blockers). Cells whose neuronal morphology was not obviously distorted by K+-blockade were chosen for the present study. Electrotonic transients were matched to a somatic shunt equivalent cylinder model adjusted with the generalized correction factor (Fdga) that constrains the parameters for neuronal anatomy. Neuronal input resistance (RN; mean +/- SEM) increased when it was corrected for somatic shunt, from 49 +/- 2 Momega (n = 80) to 179 +/- 7 Momega (n = 32). A difference was also obtained between the slowest time constant, tau0 = 16 +/- 0.9 ms (n = 49), and the dendritic membrane time constant, taumD = 33 +/- 1.6 ms (n = 36). When these electrophysiological measurements were used to calculate AN, the value obtained was similar to the anatomical measurements. Combining anatomical and electrophysiological data, somatic and dendritic input resistances were determined: RD = 182 +/- 7 Momega; Rs (with shunt) = 74 +/- 4 Momega (n = 32). The generalized correction factor, Fdga = 0.91 +/- 0.007 (n = 10), implied a short effective electrotonic length for dendrites: LD = 0.46 +/- 0.014 (n = 32). Saturating concentrations of the K+-blockers tetraethylammonium, Cs+, and Ba2+ increased RN and induced charging curves well fitted by single exponential functions in 56% of neostriatal neurons. Ba2+ greatly decreased the somatic shunt (n = 5): (RN = 216 +/- 21 Momega, tau0 = 46 +/- 2 ms, RD = 239 +/- 25 Momega, and RS = 3.2 +/- 0.5 Gomega), rendering values similar to those obtained with whole-cell recordings (e.g., RN approximately 198 Momega, RS approximately 2.62 Gomega) (n = 52). Cs+ (n = 5) had less effect on the somatic shunt (RN = 115 +/- 19 Momega, tau0 = 49 +/- 13 ms, RS = 161 +/- 8 Momega), although dendritic conductance was equally blocked (RD = 261 +/- 16 Momega). The Cs+-sensitive conductance exhibited inward rectifying properties not displayed by the Ba2+-sensitive conductance, suggesting that Cs+ preferentially acted upon inward rectifier conductances. In contrast, Ba2+ significantly acted upon linear conductances making up the somatic shunt. This suggests a differential action of different K+-blockers on the somato-dendritic membrane, implying a differential distribution of membrane conductances. Another action of K+-blockers, in about 40% of the cells, was to induce dye and probably electrical coupling between neighboring neurons.

Osteopontin expression in the kidney during unilateral ureteral obstruction

Osteopontin is a bone protein also expressed in other tissues. Increased osteopontin is thought to be associated with tissue inflammation. We used immunocytochemical analyses and polymerase chain reaction amplification of mRNA to examine osteopontin expression and regulation in unilateral ureteral obstruction (UUO) in rats, a model of inflammatory kidney disease. In the obstructed kidney, osteopontin mRNA and protein were significantly increased. The increase reached 4-fold after 1 day of UUO and persisted at this level for the 5-day duration of UUO. Immunocytochemical analyses showed increased osteopontin protein in tubular cells of the obstructed kidney cortex from days 1 through 5 of UUO. No such significant increase was apparent in the glomerulus or interstitium. Increased osteopontin mRNA and protein likewise occurred in the tubular cells of the obstructed kidney of rats that had undergone whole-body irradiation to eliminate macrophage infiltration into the experimental kidney. Purified osteopontin was found to be a chemoattractant for macrophages isolated from the rat peritoneum. Enalapril treatment, which decreases macrophage infiltration of the obstructed kidney, had no effect on the increase in osteopontin mRNA but significantly attenuated the increase in protein in tubular cells. Western blot analysis of whole cortical homogenates revealed that the osteopontin antibody recognized one protein of 67 kD. The amount of this protein was substantially decreased in kidney homogenates obtained from enalapril-treated compared to untreated animals. Increased osteopontin synthesis may, therefore, contribute in part to the inflammatory response that characterizes obstructive nephropathy.

[Association between myocardial infarction and angiotensin converting enzyme gene polymorphism in young patients]

BACKGROUND

Different studies have shown a relationship between an insertion-deletion polymorphism of the angiotensin converting enzyme (ACE) gene and the risk of ischemic heart disease, although there are no data on this association in the Spanish population.

MATERIALS AND METHOD

We have studied three groups of patients: I, healthy volunteers (n = 56, mean age 36.20 +/- 4.20 years); II, patients having presented an acute myocardial infarction (MI) < or = 50 years (n = 59, mean age 42.30 +/- 5.30 years), and III, patients with MI over the age of 50 years (n = 60, mean age 66.36 +/- 9.47 years). In all patients the genotype ACE gen was determined by an assay based on the polymerase chain reaction.

RESULTS

The distribution of the ACE genotype between the three groups were not significative. Comparing the ratio of DD/II-DI in groups II and III there were 26/33 versus 15/45 (p = 0.02864). There was no difference in the smoking, hypercholesterolemia and hypertension between groups II and III; there were only differences in familial history of ischemic heart disease; diabetes mellitus was more prevalent in the III group. A multivariate analysis showed that smoking familial history of ichemic heart disease, hypercholesterolemia and DD genotype were more prevalent in young patients (OR 3.92, 2.85, 2.36 and 1.77), whereas diabetes mellitus was more prevalent in the group of older patients. There were no differences in the ACE genotype with respect to infarct location or gender.

CONCLUSIONS

In our population DD ACE genotype is associated with MI in young patients, although smoking, family history and hypercholesterolemia show a more powerful association.

Epidemiology of invasive pneumococcal infections in infants and young children in Metropolitan Santiago, Chile, a newly industrializing country

AIM

To study the epidemiology of invasive pneumococcal infections in infants and young children in Santiago, Chile, as a representative pediatric population in a newly industrializing country where pneumococcal conjugate vaccines may be used in the future.

METHODS

A 5-year retrospective laboratory-based review (1989 to 1993) was followed by a 3-year prospective laboratory and hospital surveillance study in two of the six health administrative areas of Santiago to detect all hospitalized cases of invasive pneumococcal disease (defined as Streptococcus pneumoniae isolated from blood, cerebrospinal fluid or another normally sterile site) among infants and children (0 to 23 months of age in the retrospective and 0 to 59 months of age in the prospective study).

RESULTS

During the 5-year retrospective survey the incidence of invasive pneumococcal disease was 90.6 cases per 10(5) infants 0 to 11 months old and 18.5 cases per 10(5) toddlers 12 to 23 months old. Similar rates (60.2 per 10(5) infants and 18.1 per 10(5) toddlers) were recorded during the 3 years of prospective surveillance. Among the 110 cases in children 0 to 59 months of age detected during the 3-year prospective surveillance, 2 clinical forms, pneumonia and meningitis, accounted for 87.2% of all cases; 13 of the 49 pneumonia patients (26%) had empyema as a complication. Notably 40 of the 110 cases (36.4%) occurred before 6 months of age (63.4% of the 63 infant cases). Serotypes 1, 14, 5 and 6B were the most prevalent. Overall 76 and 69%, respectively, of S. pneumoniae isolates were antigenic types that would be covered by the 11- or 9-valent conjugate vaccines under development.

CONCLUSIONS

Invasive pneumococcal infections in Santiago, Chile, exhibit an epidemiologic pattern intermediate between that of developing and industrialized countries. The high burden of disease in early infancy dictates that an accelerated immunization schedule (beginning in the perinatal period) or maternal immunization with pneumococcal vaccines should be explored.

Photoprotector capacity of lichen metabolites assessed through the inhibition of the 8-methoxypsoralen photobinding to protein

Lichens produce a diversity of phenolic compounds, some of which efficiently absorb ultraviolet radiation, 8-Methoxypsoralen (8-MOP), commonly used in the treatment of psoriasis, binds irreversibly to proteins in the presence of ultraviolet radiation by a mechanism that is not well established. In this paper we demonstrate the photoprotector capacity of three phenolic compounds-pannarin, 1'chloropannarin and atranorin-through the inhibition of 8-MOP-human serum albumin (HSA) photobinding. The method measures the UV-filtering capacity of lichen compounds by means of a double-tube compartment (thus, solubility and interaction with the reaction medium is avoided). Photobinding was determined by measuring the radioactivity of mixtures containing 8-(methyl-3H) MOP and HSA irradiated at 360 and 310 nm in the presence of increasing concentrations of lichen phenolics. Pannarin, l'-chloropannarin and atranorin at a concentration of 10 mM and irradiated at 360 nm, inhibited photobinding to HSA by 40.4%, 31.7% and 20.1% respectively. Pannarin (10 mM) irradiated at 310 nm inhibited the photobinding by 35.2%. The participation of singlet oxygen and hydroxyl radicals was demonstrated in the photoreaction process.

Eliprodil, a non-competitive, NR2B-selective NMDA antagonist, protects pyramidal neurons in hippocampal slices from hypoxic/ischemic damage

The N-methyl-D-aspartate (NMDA) subtype of glutamate receptor is one pathway through which excessive influx of calcium has been suggested to trigger ischemia-induced delayed neuronal death. NMDA receptors are heterooligomeric complexes comprised of both NR1 and NR2A-D subunits, in various combinations. NR2B-containing NMDA complexes exhibit larger, more prolonged conductances than those lacking this subunit. We tested the ability of the non-competitive, NR2B-selective NMDA antagonist eliprodil to (a) protect synaptic transmission in in vitro hippocampal slices from hypoxia, and (b) reduce ischemic delayed neuronal death in hippocampal organotypic slice cultures. Eliprodil markedly improved the recovery of Schaffer collateral-CA1 excitatory postsynaptic potentials following a 15 min hypoxic insult, with an EC50 of approximately 0.5 microM. In contrast to this functional protection, eliprodil did not reduce delayed death of CA1 pyramidal neurons in organotypic hippocampal slice cultures treated with severe hypoxia plus hypoglycemia, though it did potently protect CA3 pyramidal neurons in the same cultures. These data indicate that NMDA receptors containing NR2B subunits may play a role in long-term recovery of hippocampal synaptic function following ischemia/hypoxia. Furthermore, the selective protection of CA3, but not CA1, pyramidal neurons suggests that NR2B-containing NMDA receptors may preferentially contribute to an excitotoxic component of ischemia-induced delayed neuronal death.

Mammalian mitochondrial D-loop region structural analysis: identification of new conserved sequences and their functional and evolutionary implications

This paper reports the first comprehensive analysis of Displacement loop (D-loop) region sequences from ten different mammalian orders. It represents a systematic evolutionary study at the molecular level on regulatory homologous regions in organisms belonging to a well defined class, mammalia, which radiated about 150 million years ago (Mya). We have aligned and analyzed 26 complete D-loop region sequences available in the literature and the fat dormouse sequence, recently determined in our laboratory. The novelty of our alignment consists of the extensive manual revision of the preliminary output obtained by computer program to optimize sequence similarity, particularly for the two peripheral domains displaying heterogeneity in length and the presence of repeated sequences. The multialignment is available at the WWW site: http://www.ba.cnr.it/dloop.html. Our comparative study has allowed us to identify new conserved sequence blocks present in all the species under consideration and events of insertion/deletion which have important implications in both functional and evolutionary aspects. In particular we have detected two blocks, about 60 bp long, extended termination associated sequences (ETAS1 and ETAS2) conserved in all the organisms considered. Evaluation against experimental work suggests a possible functional role of ETAS1 and ETAS2 in the regulation of replication and transcription and targeted experimental approaches. The analyses on conserved sequence blocks (CSBs) clearly indicate that CSB1 is the only very essential element, common to all mammalian mt genomes, while CSB2 and CSB3 could be involved in different though related functions, probably species specific, and thus more linked to nuclear mitochondrial coevolutionary processes. Our hypothesis on the different functional implications of the conserved elements, CSBs and TASs, reported so far as main regulatory signals, would explain the different conservation of these elements in evolution. Moreover the intra-order comparison of the D-loop regions highlights peculiar features useful to define the evolutionary dynamics of this region in closely related species.

Tricuspid valve repair in children with hypoplastic left heart syndrome during staged surgical reconstruction

BACKGROUND

The purpose of this study was to determine the incidence of moderate to severe tricuspid valve regurgitation in children with hypoplastic left heart syndrome (HLHS) undergoing staged surgical reconstruction, to assess the mechanisms responsible, and to evaluate the efficacy of surgical repair.

METHODS AND RESULTS

We retrospectively reviewed clinical and echocardiographic data of 59 consecutive patients with HLHS operated on at our institution. Patients with a moderate or severe degree of tricuspid regurgitation (> or =2+) demonstrated by color flow Doppler echocardiography before the hemi-Fontan or Fontan operation who underwent tricuspid valve repair were included. Patients with HLHS and coexisting atrioventricular septal defect were excluded from the study. Severity of insufficiency was graded on a scale from 1 to 4+ by Doppler color flow mapping. Tricuspid valve morphology, degree of tricuspid valve regurgitation, and right ventricular function were assessed before and after tricuspid valvuloplasty. Eight patients (8/59; 14%) were found to have a minimum of 2+ tricuspid valve regurgitation before hemi-Fontan or Fontan operations. In five of eight patients (62%; Group A), the valve was found to be myxomatous, thickened, and redundant. There were multiple regurgitant jets in three of five (60%) patients in this group. In three of eight patients (37%; Group B), the valve had a normal echocardiographic appearance and regurgitation was the result of a lack of complete leaflet coaptation. All eight patients underwent tricuspid valvuloplasty, and all experienced a decrease in regurgitation. In five of eight (62%) patients, there was a reduction in insufficiency of two grades of severity and in three of eight (37%) patients, there was a one-grade improvement. Tricuspid valve stenosis was not documented in any of the patients after tricuspid valvuloplasty. In seven of eight (87%) patients, right ventricular function was assessed as fair before tricuspid valvuloplasty repair and improved to good in five of seven (71%) patients after the procedure. The remaining patient had good function both at baseline and after tricuspid valvuloplasty.

CONCLUSIONS

Moderate to severe tricuspid valve regurgitation is a common finding in patients with HLHS undergoing staged surgical reconstruction and can result from either abnormal valve morphology or incomplete leaflet coaptation. Tricuspid valvuloplasty during either the hemi-Fontan or Fontan stages of reconstruction carries a high success rate and is associated with improved right ventricular function.

[The male factor. I. Testicular function and gametogenesis]

The knowledge and treatment of human reproduction impairments have had an outstanding development during the last 15 years, mainly in topics related with infertility and sterility. Unfortunately in the area of male reproduction development has not been the same and despite the efforts accomplished, progress in the diagnosis and therapeutics of male infertility is limited. The functions of the male gonad are sperm production as well as the synthesis and secretion of steroid hormones, mainly testosterone. The efficient regulation of these functions depends on both the precise pituitary secretion of gonadotropic hormones and the endocrine, paracrine and autocrine responses of the testicular somatic cells to this stimulation. In this review we discuss the main events associated with the spermatogenic process, including the interactions among the testicular somatic cells and some characteristics of the physiological function of the hypothalamus-pituitary-testicle axis, as well as some pathophysiological states related to male infertility due to "pretesticular causes".

[The male factor. II. Spermatozoa. Structure and function]

In the "male factor" entity, the structural and functional correlation determining the sperm fertilizing capacity is constituted by a group of cellular factors that must be evaluated in the semen of the infertile men. Structurally the spermatozoa of the head, the middle piece and the flagellum. The head has a highly condensed haploid nucleus, surrounded by a thin layer of cytoplasmic material, which is covered in a cap-like fashion by the membrane limiting the acrosome. This last organelle, which has characteristics similar to those of a secretory granule, secretes in a programmed way the hydrolytic enzymes that facilitate the fertilization process. The middle piece contains the mitocondrail sheet, responsible for the energy metabolism of the sperm cell. The flagellum has the same basic structure of other cilia or flagella, but also has particular characteristics due to the presence of the outer dense fibers and the fibrous sheath. In the semen analysis from infertile men the abnormalities most frequently observed belong to the number, morphology, variability, motility of capacitation-acrosome reaction of the sperm cells. However, due to the apparent multifactorial etiology of the male factor, now a days we only have few options for medical or pharmacological treatment. In this paper we review the morphology and ultrastructure considered as "normal" in the human spermatozoa, as well as we describe the most frequent alterations in these parameters. At the same time, we discuss the impact of sperm motility and of the capacitation-acrosome reaction process in male fertility.

[The male factor. III. Importance, diagnosis and perspectives]

According to the World Health Organization, the male factor is present in 40-50% of infertile couples, therefore the importance of the continuity in multidisciplinary studies related to understand the mechanisms regulation the male reproductive process. Semen analysis is still almost the only instrument for the study of men with disruptions in their fertility. However, the main problem to establish a diagnosis with predictive value for male infertility, is the fact that the morphological and/or functional characteristics of the male gamete that determine its fertilizing capacity are still in the process of validation. Even more, the correlations among semen characteristics and bioactive hormones concentrations in serum, and the individual fertility potential have not been established either. In this context, we discuss here some topics that we considered of great importance in relation to male fertility diagnosis, i.e. the main causes of infertility, the advances in the recognition of the morpho-functional correlation that determines the fertilizing capacity of the male gamete and the criteria that prevail in the laboratory to proper handle and evaluate the semen samples.

Dopamine facilitates striatal EPSPs through an L-type Ca2+ conductance

When synaptic activity is evoked from relatively depolarized membrane potentials, D1 receptor agonists enhance the depolarization level and slow the decay of synaptic responses recorded from neostriatal spiny neurons. The population spikes' amplitude is also increased. These D1 actions facilitate firing and are evident in the presence of both NMDA and GABA selective blockers. Thus, dopaminergic D1 receptor activation facilitates the AMPA-mediated EPSP in these conditions. This facilitatory effect could be suppressed by L-type Ca2+ channel antagonists (200 nM calciseptine and 5 microM nicardipine), suggesting that it is mediated by an increase in L-current. D1-receptor activation thus mediates orthodromic facilitation of neostriatal neurons when evoked from depolarized membrane potentials. This reinforces the dopamine facilitation mediated through NMDA responses.

Early vs conventional extubation after cardiac surgery with cardiopulmonary bypass

OBJECTIVES

Sedation and ventilation overnight after cardiac surgery is common practice. However, early extubation may be feasible with no increase in postoperative complications. This study examines (1) if early extubation is possible in a significant number of patients, (2) if it reduces ICU stay, and (3) if this practice increases postoperative complications.

DESIGN

Prospective, controlled, randomized clinical trial.

PATIENTS AND METHODS

We randomized 404 consecutive patients to early extubation (7 to 11 h postoperatively) (group A, 201 patients) or conventional extubation (between 8 and 12 AM the following day) (group B, 203 patients). Variables included type and severity of the disease, surgical risk, type of operation, operative incidences, postoperative complications, duration of mechanical ventilation, intubation and ICU stay, bleeding, reoperation, vasoactive drugs, and mortality.

RESULTS

Groups were comparable. Extubation within the preestablished time was successful in 60.2% of patients in group A and 74.4% in group B. Median ICU stay was 27 h in group A and 44 h in group B (p=0.008). Discharge from ICU within the first 24 h postoperatively was 44.3% in group A and 30.5% in group B (p=0.006). There was no significant difference in complications between groups. Successfully extubated patients in group A had more reintubation and prolonged ventilation than in group B.

CONCLUSIONS

(1) Sixty percent of our patients were extubated within 11 h of operation. (2) As a result, the length of stay in ICU was reduced and the percentage of patients discharged within 24 h was increased. (3) There was no increase in clinically important postoperative complications.

D1 receptor activation enhances evoked discharge in neostriatal medium spiny neurons by modulating an L-type Ca2+ conductance

Most in vitro studies of D1 dopaminergic modulation of excitability in neostriatal medium spiny neurons have revealed inhibitory effects. Yet studies made in more intact preparations have shown that D1 receptors can enhance or inhibit the responses to excitatory stimuli. One explanation for these differences is that the effects of D1 receptors on excitability are dependent on changes in the membrane potential occurring in response to cortical inputs that are seen only in intact preparations. To test this hypothesis, we obtained voltage recordings from medium spiny neurons in slices and examined the impact of D1 receptor stimulation at depolarized and hyperpolarized membrane potentials. As previously reported, evoked discharge was inhibited by D1 agonists when holding at negative membrane potentials (approximately -80 mV). However, at more depolarized potentials (approximately -55 mV), D1 agonists enhanced evoked activity. At these potentials, D1 agonists or cAMP analogs prolonged or induced slow subthreshold depolarizations and increased the duration of barium- or TEA-induced Ca2+-dependent action potentials. Both effects were blocked by L-type Ca2+ channel antagonists (nicardipine, calciseptine) and were occluded by the L-type channel agonist BayK 8644-arguing that the D1 receptor-mediated effects on evoked activity at depolarized membrane potential were mediated by enhancement of L-type Ca2+ currents. These results reconcile previous in vitro and in vivo studies by showing that D1 dopamine receptor activation can either inhibit or enhance evoked activity, depending on the level of membrane depolarization.

A follow-up study of EEG coherences in children with different pedagogical evaluations

A follow-up study on EEG coherence values was carried out with 46 school-age children divided into three pedagogical groups considering their reading and writing abilities (normal subject and children with mild and with serious reading-writing problems). EEGs were recorded at rest, with eyes closed in 15 referential derivations that gave 105 possible coherence values. Coherence was calculated after the elimination of the average reference. Repeated Measure ANOVAs were calculated to evaluate the effects of time, sex, reading-writing problems and their interactions. The second EEG recordings were taken 2-3 years after the first. The results revealed significant increase of coherence values during the time lapse studied, consisting of an increase of frontal coherences in all bands, with the exception of the theta band. The most numerous changes occurred in the alpha band. Very few differences in coherence values were observed between the two EEG recordings by pedagogical groups and by sex suggesting a similar but not igual maturation of coherences of boys and girls and of the three pedagogical groups, in this age range studied. These findings suggests an abnormal coherence development for the reading disabled group, as well as different coherence maturation for boys and girls in this time lapse studied.

Evolution of cerebral edema and its relationship with power in the theta band

In previous papers we have proposed that in patients with space-occupying lesions, delta power was related with the volume of the lesion and theta power with the volume of the edema. In this report we analyze the evolution of 10 patients with space-occupying lesions in whom we measured the volume of the lesion and of the edema before and after treatment that produced changes in these volumes. EEGs were recorded in the leads of the 10-20 system referenced to linked earlobes. Delta and theta powers were calculated for voltage and current source densities (CSD) and compared with age-norms to compute conventional Z-maps. These maps provide probability statements about the deviation of observed values from the norm. Rank correlations between the change in the volume of the lesion before and after treatment and the change in Z-values before and after treatment were significant only in the delta band. However, rank correlations between the change in the volume of the edema and the change in EEG Z-values were only significant in the theta band. These correlations were higher for CSD than for voltage estimates. We also observed that the site of the lesion and of the edema was better represented by CSD maps than by voltage maps. These results are also in agreement with our previous reports, in which we observed more precise localization of brain lesions by CSD than by voltage estimates.

EEG delta activity: an indicator of attention to internal processing during performance of mental tasks

In previous papers we proposed that an increase in delta EEG activity during mental tasks might be related to an increase in subjects' attention to internal processing. In this paper we have made a narrow band analysis to detect those EEG frequencies that change selectively during the performance of a mental task that requires attention to internal processing. Two different experiments were performed: (1) a difficult mental calculation task and a control stimulus with the same physical characteristics as the arithmetical symbols were presented in random order; (2) the Sternberg paradigm for the analysis of short term memory using a memory set of 5 or 3 digits was also presented in random order. Referential recordings to linked ears were obtained in all leads of the 10/20 system. In the first experiment, the increase of power from 1.56 to 5.46 Hz was observed only during the performance of the task and not during the control condition. In the Sternberg paradigm, the increase of power from 1.56 to 3.90 Hz was greater during the difficult than during the easy condition. These results support our hypothesis that an increase in delta activity may be related to attention to internal processing during the performance of a mental task.

Multiple paternity in two natural populations (orchard and vineyard) of Drosophila

Male mating success is an important fitness component in Drosophila. The seminal fluid conveyed with the sperm inhibits the proclivity of the female to remate and reduces her fitness. Nevertheless, females may remate before they have exhausted the sperm from the first male and consequently use sperm from both males. We have studied concurrent multiple paternity (CMP) in two Drosophila melanogaster populations, from an apple orchard and a vineyard just after harvest. CMP is high in both populations, somewhat greater than 50%; but it is not significantly higher in the vineyard, where the population density is much greater than in the orchard. Population density had been thought to be an important determinant of CMP incidence. We have used four gene loci coding for enzymes as independent markers for detecting CMP.

Ventricular outflow tract reconstructions with cryopreserved cardiac valve homografts. A single surgeon's 10-year experience

OBJECTIVE

From January 1, 1985 through December 31, 1994, one surgeon implanted cryopreserved valved homografts into 149 patients--65 since December 1988. This latter series (II) was accomplished in a single hospital, facilitating patient follow-up with biannual echocardiograms. Analysis of these 65 patients is the primary focus of this report; the indications and early surgical results for the two parts of the series (I and II) are compared to assess the evolution of a single surgeon's use of homografts in a mixed pediatric and adult practice.

METHODS

Fifty-one variables for each patient (series II) were entered into a computerized database and analyzed (multivariate and univariate) using SPSS 6.1 software (Statistical Products and Service Solutions, Chicago, IL). Cox proportional hazard model was used to identify the independent contribution of each variable for patient mortality and homograft failure. Cumulative survival estimates were made using Kaplan-Meier analysis. Homograft failure was defined as requirement for replacement or death. In series I, there were 41 left ventricular outflow tract (LVOT) reconstructions (31 adult) and 43 right ventricular outflow tract (RVOT) reconstructions (42 pediatric). In series II, there were 55 RVOT reconstructions (52 pediatric) and 10 LVOT reconstructions (7 adult).

RESULTS

There were no technical surgical failures. Total surgical mortality rate was 6% (5/84) in series I (3 LVOT, 2 RVOT) and 15% (10/65) in series II (2 LVOT, 8 RVOT) (I vs. II NS; p = 0.11, two-tailed Fisher exact test). By the Cox analysis, only age < 2 years (p < 0.03) and cross-clamp time > 120 minutes (p < 0.05) were significant predictors for death. Age-based survival curves were compared in a sequential bivariate analyses (log rank test) and age < 2 years again was a significant predictor of decreased patient survival (p < 0.006). Actuarial freedom from patient death or reoperation for homograft failure was 82% +/- 7% at 1000 days and 77% +/- 10% at 2000 days. Three patients required re-replacement for homograft failure (5.4%); one of these patients died. The only significant predictor of homograft failure was postoperative endocarditis (p < 0.05). Homograft performance was evaluated by an extensive echocardiography protocol: in surviving patients and homografts, three valved conduits were judged to have severely impaired performance (stenosis or regurgitation), awaiting surgical replacement for a putative total homograft-related structural failures rate of 11% at 5 1/2 years.

CONCLUSIONS

Comparisons of series I and II shows, in one surgeon's practice, an evolution away from use of cryopreserved homografts for LVOT reconstructions except when needed for destructive bacterial endocarditis or complex congenital anatomy. Homograft efficacy and durability were similar in RVOT and LVOT positions, with 78.5% of patients surviving at 5 1/2 years; in surviving patients, 89% of homografts have continued to function well. Homografts are not immune to prosthetic bacterial endocarditis, and its occurrence is associated with accelerated deterioration. Cryopreserved homograft valves are an imperfect but satisfactory biological material for specific ventricular outflow reconstructions.