Multi-level modelling of conception in artificial insemination by donor

Data on insemination with donor's sperm have a crossed hierarchical structure due to the coexistence of female factors (ovulatory cycles within pregnancy attempt within women) and male factors (inseminations within donations within donors). A crossed random multi-level logistic model, taking account of this structure, permits an improved estimation of the fixed effects and provides insights into their influence at each level in the hierarchy. We present an efficient algorithm for fitting such models using alternating EM steps. We further discuss the inclusion of compositional covariates to determine what information the quality of a donation conveys regarding the donor basal fecundability and on the specific sperm donation.     

Perforated appendicitis within an inguinal hernia: case report and review of the literature

The finding of the vermiform appendix within an inguinal hernia sac is not uncommon. However, it is rare to find a perforated appendix within an inguinal hernia. An unusual case of an incarcerated and perforated appendix within an inguinal hernia complicated by an intra-abdominal abscess is reported herein. Perforated appendix as a cause of abscess was revealed during abdominal exploration. Clinicians are encouraged to be aware of this unusual entity, which is rarely recognized before exploration.     

Effect of luminance contrast on BOLD fMRI response in human primary visual areas

In this study, we examined the effect of stimulus luminance contrast on blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging within human visual cortex (V1 and extrastriate). Between experiments, the calibrated luminance of a single red LED covering 2 degrees of the subject's visual field was changed relative to a constant background luminance. This stimulus provided a different foveal luminance contrast for each experiment. We used an echo planar imaging sequence to collect blood-oxygenation-sensitive images during and in the absence of the presented stimulus. Our results showed that within V1 there was an increase in the spatial extent of activation with increasing stimulus contrast, but no trend was seen within extrastriate. In both V1 and extrastriate, the local mean activation level for all activated image pixels remained constant with increasing luminance contrast. However, when we investigated activated pixels common to all luminance contrast levels, we found that there was an increase in the mean activation level within V1, but not within extrastriate. These results suggest that there is an increase in the activity of cells in V1 with increasing luminance contrast.     

The radiology of transsphenoidal hypophysectomy: a review of 100 cases

This report describing the radiology of transsphenoidal hypophysectomy based on a review of 100 consecutive surgical procedures. Preoperative laminographic evaluation of the sphenoid sinus is an important aid in planning the most direct surgical approach to the pituitary. It is also useful in defining the many anatomic structures that may be injured inadvertently at the time of surgery. Intraoperative radiography or fluoroscopy is helpful in identifying the sella floor and as an aid in preventing loss of orientation within a capacious sinus. Various changes occur within the sphenoid sinus following surgery, some transient and others persistent. The surgical defect is usually difficult to identify on routine roentgenograms but is clearly visible on lateral laminography. A persistent soft tissue mass within the sinus is usually a manifestation of fascia and fat placed as a seal within the sinus.     

Evolutionary comparisons of RecA-like proteins across all major kingdoms of living organisms

Protein sequences with similarities to Escherichia coli RecA were compared across the major kingdoms of eubacteria, archaebacteria, and eukaryotes. The archaeal sequences branch monophyletically and are most closely related to the eukaryotic paralogous Rad51 and Dmc1 groups. A multiple alignment of the sequences suggests a modular structure of RecA-like proteins consisting of distinct segments, some of which are conserved only within subgroups of sequences. The eukaryotic and archaeal sequences share an N-terminal domain which may play a role in interactions with other factors and nucleic acids. Several positions in the alignment blocks are highly conserved within the eubacteria as one group and within the eukaryotes and archaebacteria as a second group, but compared between the groups these positions display nonconservative amino acid substitutions. Conservation within the RecA-like core domain identifies possible key residues involved in ATP-induced conformational changes. We propose that RecA-like proteins derive evolutionarily from an assortment of independent domains and that the functional homologs of RecA in noneubacteria comprise an array of RecA-like proteins acting in series or cooperatively.     

Grief as pathology: The evolution of grief theory in psychology from Freud to the present.

The emergence of grief as a topic worthy of psychological study is an early 20th century invention. Freud published his influential essay on mourning and melancholia in 1917. Since he proposed the concept of “grief work,” contemporary psychologists have examined his theory empirically and have claimed that grief is a pathology that should be included within the psychological domain. How, and why, has grief theory evolved within the discipline of psychology in this way? In what ways do these changes in the understanding of grief coincide with other historical developments within the discipline? In this article, I trace the development of grief, originally conceived by Freud within a psychoanalytic and nonpathological framework, to the current conceptualization of grief within the disease model. I show how grief theory has evolved within the discipline of psychology to become (a) an object worthy of scientific study within the discipline, and subsequently, (b) a pathology to be privatized, specialized, and treated by mental health professionals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hydraulic Performance of Fish Bypass-Pools for Irrigation Diversion Channels

This paper presents the results of an exploratory study on the hydraulics of a fish bypass-pool that is built to facilitate successful fish passage through an irrigation diversion channel. The hydraulic performance of the bypass-pool was investigated by performing two major experimental runs to evaluate the flow recirculation patterns within the pool when two different outlet configurations were used. This was to determine which outlet design prevents or minimizes the presence of “stagnant” regions within the pool, where fish could rest until ensnared by a predator. These experiments show that the flow from the forebay area of the irrigation diversion structure, entering the pool as a jet, diffuses because of the circulation and turbulence within the bypass pool. The diffusing jet impinges upon the back-wall of the pool and dives into the pool creating several recirculation patterns within the pool. The results collected in this study provide useful information about the jet velocity decay through the pool, the eddy length scale within the pool, the velocity contours, and the level of energy dissipation within the pool. A rational basis was developed for evaluation of the hydraulic performance of a bypass-pool by considering the recirculation pattern and turbulent flow microstructures formed within the pool.     

Use of electron spectroscopic imaging to determine element composition of the melanin granules in the stria vascularis of the guinea pig

Electron spectroscopic imaging (ESI) was used to analyze the element content of melanin granules in the stria vascularis seen in ultrathin sections of Spurr-embedded cochleae of the guinea pig. To determine element composition, ESI images were taken at different ionization edges, and non-specific background signals were subtracted digitally by an image processing system. The presence of calcium and nitrogen in the melanin granules could be demonstrated clearly. The calcium identified in the melanin granules was then compared with the spatial distributions of calcium binding sites after the application of an antimonate precipitation method, which was used to localize loosely bound calcium. Despite a high calcium concentration within the granules, only very small single scattered calcium precipitates could be detected between these structures as compared with the amount of calcium precipitates attached to the plasma membrane or located within the cell nuclei. The nearly complete absence of precipitates within the melanin granules after the application of antimonate suggests differences in calcium binding and mobility involved in various physiological processes of ion balance regulation within the stria vascularis.     

Mutation, sequence analysis, and association studies of alpha-synuclein in Parkinson's disease

A mutation within the alpha-synuclein gene on human chromosome 4 has been reported to segregate with PD in an Italian family. We screened a sample of familial cases of PD for mutation in the alpha-synuclein gene. None of the familial cases of PD carried a mutation within the alpha-synuclein gene, and no association was detected between PD and alleles of a dinucleotide repeat marker within the alpha-synuclein gene. We conclude that variation within the alpha-synuclein gene does not play a significant role in the risk for PD in our sample.     

Widespread sites of brain stem ventilatory chemoreceptors

We produced local tissue acidosis in various brain stem regions with 1-nl injections of acetazolamide (AZ) to locate the sites of central chemoreception. To determine whether the local acidosis resulted in a stimulation of breathing, we performed the experiment in chloralose-urethan anesthetized vagotomized carotid-denervated (cats) paralyzed servo-ventilated cats and rats and measured phrenic nerve activity (PNA) as the response index. Measurements of extracellular brain tissue pH by glass microelectrodes showed that AZ injections induced a change in pH at the injection center equivalent to that produced by an increase in end-tidal PCO2 of approximately 36 Torr and that the change in brain pH was limited to a tissue volume with a radius of < 350 microns. We found AZ injections sites that caused a significant increase in PNA to be located 1) within 800 microns of the ventrolateral medullary surface at locations within traditional rostral and caudal chemosensitive areas and the intermediate area, 2) within the vicinity of the nucleus tractus solitarii, and 3) within the vicinity of the locus coeruleus. Single AZ injections produced increases in PNA that were < or = 69% of the maximum value observed with an increase in end-tidal PCO2. We conclude that central chemoreceptors are distributed at many locations within the brain stem, all within 1.5 mm of the surface, and that stimulation of a small fraction of all central chemoreceptors can result in a large ventilatory response.     

The amounts of nucleotide variation within and between allelic classes and the reconstruction of the common ancestral sequence in a population

The amounts of nucleotide variation within and between allelic classes were studied. The expectation and variance of the number of segregating sites and the expectation of the average number of pairwise differences among a sample of DNA sequences were obtained by using the theory of gene genealogy with no recombination. When the ancestral allelic class is unknown, it was found that the amount of variation within an allelic class increases with its frequency in the sample, while the amount of variation between two allelic classes is the largest when the two allelic classes exist equally. On the other hand, if we know the ancestral allelic class, as the frequency of the mutant allelic class increases, the amounts of variation within the mutant allelic class and between two allelic classes increase and the amount of variation within the ancestral allelic class decreases. As an example, we analyzed the polymorphism in the ND5 gene of Drosophila melanogaster and constructed the common ancestral sequence with high confidence, suggesting that the pattern of polymorphism within species gives useful information to know the ancestral sequence of the species.     

Utterance rate and linguistic properties as determinants of lexical dysfluencies in children who stutter

Two important determinants of variation in stuttering frequency are utterance rate and the linguistic properties of the words being spoken. Little is known how these determinants interrelate. It is hypothesized that those linguistic factors that lead to change in word duration, alter utterance rate locally within an utterance that then gives rise to an increase in stuttering frequency. According to the hypothesis, utterance rate variation should occur locally within the linguistic segments in an utterance that is known to increase the likelihood of stuttering. The hypothesis is tested using length of tone unit as the linguistic factor. Three predictions are confirmed: Utterance rate varies locally within the tone units and this local variation affects stuttering frequency; stuttering frequency is positively related to the length of tone units; variations in utterance rate are correlated with tone unit length. Alternative theoretical formulations of these findings are considered.     

Lysosomal targeting of P-selectin is mediated by a novel sequence within its cytoplasmic tail

Signals controlling the intracellular targeting of many membrane proteins are present as short sequences within their cytoplasmic domains. P-selectin is a type I membrane protein receptor for leukocytes, acting during the inflammation response. Heterologous expression experiments have demonstrated that its 35-residue cytoplasmic tail contains signals for targeting to synaptic-like microvesicles, dense-cored granules, and lysosomes. We have examined the lysosomal targeting information present within the cytoplasmic tail by site-directed mutagenesis of horseradish peroxidase-P-selectin chimeras followed by transient transfection in H.Ep.2 cells. Assaying lysosomal targeting by subcellular fractionation as well as intracellular proteolysis, we have discovered a novel lysosomal targeting signal, KCPL, located within the C1 domain of the cytoplasmic tail. Alanine substitution of this tetrapeptide reduced lysosomal targeting to the level of a tailless horseradish peroxidase-P-selectin chimera, which was previously found to be deficient in both internalization and delivery to lysosomes. A proline residue within this lysosomal targeting signal makes a major contribution to the efficiency of lysosomal targeting. A diaminobenzidine density shift procedure established that chimeras with an inactivated KCPL sequence are present within transferrin-positive compartments. Such a mutant also displays an increased level of expression at the plasma membrane. Our results indicate that the sequence KCPL within the cytoplasmic tail of P-selectin is a structural element that mediates sorting from endosomes to lysosomes.     

Laboratory Measurements of Flow and Turbulence in Discontinuous Distributions of Ligulate Seagrass

Turbulent flow characteristics were investigated in laboratory flume studies of a ligulate plant canopy interrupted by a gap representing discontinuities observed in seagrass prairies. The reliability of velocity measurements obtained using an acoustic Doppler velocimeter within the canopy was shown using specifically designed experiments. In relatively fast flow (mean velocity 5.5?cm?s?1), the mean flow profile was logarithmic above the canopy, had an inflection point near its top, and uniformly low values within it. Within the gap, a recirculation cell formed. Reynolds stress maxima were approximately coincident with the mean flow inflection point. Quadrant analysis revealed an ejection-dominated upper layer, a sweep-dominated region around the top of the canopy and within the gap, and no dominant quadrant within the canopy. In slower flow (mean velocity 1.7?cm?s?1) the plants were quasiemergent and the flow fields more uniform. Sweeps similarly dominated the region near the top of the canopy and within the gap. In both flows, autocorrelation of longitudinal velocity fluctuations showed a Lagrangian time scale maximum at the downstream end of the gap.     

The medical-psychiatry unit. A pilot study of conjoint care within an Irish general hospital

The establishment of medical-psychiatry units within the general hospital is an important advancement for psychiatry and has met with favorable response within the American health care system. A brief account is given here of the piloting of such a unit within an Irish hospital, and the merits of this strategy are discussed.     

Analyses of the dynamic processes of liquid metal filtration

The dynamic processes of liquid metal filtration with reticulated ceramic filters prior to filter “ripening” were analyzed theoretically by examining the changes in the filter coefficient as a function of its independent variables during the filter aging period. Correlations relating the filter coefficient and pressure gradient to the specific deposit (volume fraction of nonmetallic particles captured within the filter) were derived and then solved numerically to simulate the dynamic behavior of liquid aluminum filtration. Simulated results showed that the particle-capture process within the filter possesses an autocatalytic behavior. The filtration efficiency of, and pressure gradient within, the filter were found to increase with filtration time and with particle concentration within the melt. These increases were, however, negligibly small for the first 2-hour period of filtration if the particle concentration within the melt was lower than 1 ppm by volume; when the particle concentration reached 10 ppm, increases in filtration efficiency became appreciable. This corresponds to a passage of about 160,000 kg of 10-ppm liquid aluminum per square meter of filter area.     

Interactions Between Phasic Alerting and Spatial Orienting: Effects of Normal Aging and Alzheimer's Disease.

The effects of aging and Alzheimer's disease (AD) on phasic alerting and exogenous spatial orienting were examined within a single precuing task. Phasic alerting decreased with normal aging and was completely eliminated with AD. AD patients also demonstrated an increased spatial orienting effect, attributable to an increased benefit from spatial orienting that was associated with a decreased benefit from nonselective alerting. These results suggest that performance within the precuing paradigm reflects the product of an interaction between nonselective alerting processes and spatially selective orienting processes. The results also highlight the importance of simultaneously assessing alerting and orienting within the same task, because changes attributable to alerting may otherwise be attributed incorrectly to changes in 1 or more processes associated with spatial orienting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prediction of psychosis. A step towards indicated prevention of schizophrenia

BACKGROUND: The identification of people at high risk of becoming psychotic within the near future creates opportunities for early intervention prior to the onset of psychosis to prevent or minimise later ill-health. The present study combines current knowledge about risk factors for schizophrenia with our knowledge of psychotic prodromes in an attempt to identify a group particularly vulnerable to impending psychosis. We wanted to identify people with high likelihood of transition to psychosis within a follow-up period of 12 months, and to determine the rate of transition to psychosis in this group. METHOD: Various state and trait risk factors for psychosis were used alone and in combination to operationally define a putatively high-risk group. Operationalised criteria for onset of psychosis were established. The individuals were assessed monthly on measures of psychopathology for six months. RESULTS: Eight out of 20 people made the transition to frank psychosis within a six-month follow-up period. Follow-up of this group is still in progress, and the 12 month transition rate might prove to be higher still. CONCLUSIONS: We have demonstrated that it is possible to identify individuals with a high likelihood of onset of psychosis within a brief follow-up period. This lays the foundation for early treatment in an attempt to prevent, delay or minimise the severity of first onset of schizophrenia.     

Transport, manipulation, and reaction of biological cells on-chip using electrokinetic effects

A microfluidic system was fabricated on a glass chip to study mobilization of biological cells on-chip. Electroosmotic and/or electrophoretic pumping were used to drive the cell transport within a network of capillary channels. Whole cells such as Saccharomyces cerevisiae, canine erythrocyte, and Escherichia coli were employed in this work. Photographs are presented to illustrate how cells are selected and transported from one location to another within the capillary network, with velocities up to about 0.5 mm/s in capillaries with a 15- x 55-microns cross section. The mixing of canine erythrocytes with the lysing agent sodium dodecyl sulfate, at an intersection within the chip, was performed to demonstrate that cell selection and subsequent reaction can be accomplished within the microchip.