Common misconceptions about cognitive mediation of treatment change: a commentary to Longmore and Worrell (2007)

The article by Richard J. Longmore and Michael Worrell [Clinical Psychology Review, Volume 27, 2007, pp. 173-187] reviews a selection of studies showing no significant difference between treatment conditions that include formal cognitive restructuring techniques and other behavioral treatment modalities that do not include techniques to directly challenge cognitions. Based on this literature, Longmore and Worrell question the validity of the cognitive behavioral treatment model and argue that changes in symptoms are not mediated by changes in cognitions. Longmore and Worrell's arguments are based on common misconceptions about mediation models of treatment change. This commentary discusses and clarifies these misconceptions.     

Ribosomal RNA gene organization in Cryptosporidium parvum

The cytoplasmic ribosomal RNA (rRNA) genes of the Apicomplexan protozoan parasite Cryptosporidium parvum have been analyzed with respect to size, copy number, organization and structure. The small and large subunit rRNAs are 1.7 and 3.6 kb, respectively. A 151 bp putative 5.8S rRNA gene was identified. The rDNA unit is 5′ small subunit rRNA–internal transcribed spacer 1–5.8S rRNA–internal transcribed spacer 2–large subunit rRNA 3′. There are five copies of the rDNA unit per haploid genome and they are not organized in a conventional head to tail tandem array with a conserved external transcribed spacer. The rDNA units are dispersed through the genome to at least three chromosomes. At least two of the rDNA units are single unlinked copies on different chromosomes. There are two structurally distinct types of rDNA unit, Type A and B, with marked differences in the internal transcribed spacer regions. There are four copies of the Type A rDNA unit and one copy of the Type B rDNA unit.     

Relation of Intromissions to the Female''s Postejaculatory Refractory Period in Rats

The objectives of this study were to investigate the temporal aspects of female sexual behavior during single and multiple ejaculatory tests. Females were tested in a two-compartment chamber where they could escape from the male following sexual contacts. In Experiment 1, correlation analysis showed that the number of intromissions received by the female over 3 ejaculatory series was positively correlated with the female's postejaculatory refractory period (PER). In Experiment 2, females receiving 2–4 intromissions before ejaculation had a PER that did not differ from those receiving 5–15 (average 10) intromissions preceding ejaculation. However, if the male ejaculated on the first or second intromission, the female's PER was significantly shorter than the other groups and did not differ from her return latency after an intromission without ejaculation. Females receiving 24–31 intromissions preceding ejaculation exhibited the longest PER. Analysis revealed that the number of intromissions received by females before ejaculation was positively correlated with the female's PER. We concluded that the male's ejaculatory reflex, seminal emission, and postejaculatory behavior alone without at least 2 preceding intromissions were not sufficient to induce a female's PER comparable to that seen after an ejaculation during normal copulation. In addition, the number of intromissions received by the female preceding ejaculation was positively correlated with the female's PER if the range of intromission frequency was large enough.     

The antiphospholipid antibody syndrome: A riddle wrapped in a mystery inside an enigma

The antiphospholipid antibody syndrome (APS) is the association of certain clinical features with the presence of antiphospholipid antibodies (APA) in the serum or plasma of affected individuals. APS may be primary or secondary to another disease, typically autoimmune diseases such as systemic lupus erythematosus (SLE).The prototypic clinical features are thrombotic events (venous and arterial) and pregnancy morbidity (recurrent fetal loss, severe preeclampsia, eclampsia, and multiple spontaneous abortions). The term antiphospholipid antibody is a misnomer since it now appears that APA are actually directed against protein phospholipid complexes. APA may also occur secondary to infections however these APA seem to be directed at phopsholipid only and are transient. Particular phospholipid-binding proteins associated with APS include beta 2-glycoprotein I (B2GPI), prothrombin, and annexin V. A recent International Consensus Statement defines Definite APS as the presence of certain clinical findings (either a thrombotic event and/or pregnancy morbidity) and the presence and persistence of laboratory evidence of APA [either the lupus anticoagulant (LA) and/or anticardiolipin antibodies (ACL)]. Other clinical features associated with APS include thrombocytopenia, various skin conditions, cardiac valvular diseases, and diverse neurological conditions as outlined in the main text. These other features may be part of APS but require further evidence to establish their pathological and clinical validity. Other laboratory tests of interest include anti-B2GPI, antiprothrombin, and antiphosphatidylserine antibodies. The diagnostic and clinical importance of these additional laboratory tests remains to be determined.APA are estimated to be present in up to 5% of the general population, with the prevalence increasing with age. APA are estimated to be present in 12% or more of patients with thrombosis. ACL are present in 12 to 30% of patients with SLE and LA are present in 15 to 34% of patients with SLE. There is often concordance between LA and ACL however this is not always true. APA (both ACL and LA) are associated with thromboembolic events. Venous thrombosis is more common than arterial thrombosis and a minority of patients have both. LA is more strongly associated with thrombosis than ACL. The estimated yearly incidence of thrombosis in individuals with APA is 1% for those with no history of thrombosis, 4% for those with SLE, and 6% for those with high titer immunoglobulin G (IgG) ACL. The presence of LA, and possibly of medium to high titers of IgG ACL, help identify patients at risk for thrombosis.     

A pteridine reductase gene ptr1 contiguous to a P-glycoprotein confers resistance to antifolates in Trypanosoma cruzi

We have isolated the pteridine reductase-1 gene (ptr1), from Trypanosoma cruzi (Y strain), located contiguous to the Trypanosoma cruzi P-glycoprotein-2 (tcpgp2). The gene encodes a member of the family of short-chain dehydrogenases, enzymes that are involved in several oxidoreduction reactions. One member of the family, pteridine reductase-1 (PTR1) has been previously described in Leishmania as being involved in antifolate resistance. The ptr1 gene from T. cruzi presents an 828 bp open reading frame, coding for a 276 amino acid protein with a predicted molecular mass of 30 kDa. The deduced amino acid sequence exhibited a remarkable homology with the ptr1 genes of Leishmania major and Leishmania tarentolae. Southern blot analysis using a specific probe indicated that T. cruzi PTR1 is encoded by a single copy gene located in two chromosomes of about 0.9 and 1.2 Mb. Western blot analysis using a polyclonal antiserum against recombinant PTR1 revealed that the protein is only expressed in the epimastigote forms of the parasite; we did not detect the protein either in the amastigote or trypomastigote forms. Purified recombinant PTR1 exhibits a NADPH-dependent pteridine reductase activity comparable with those described in Leishmania. Gene transfection experiments using the pTEX expression vector show that, under the conditions tested, T. cruzi PTR1 is involved in resistance to the methotrexate, aminopterin and trimethoprim antifolates.     

In vitro demonstration of serological cross-reactivity between Ichthyphthirius multifiliis foquet and Tetrahymena pyriformis lwoff

The antigenic relation between $\text{Tetrahymena pyriformis}$ (Ehrenberg, 1830) Lwoff 1947 and $\text{Icthyophthirius multifiliis}$ Fouquet 1876 was investigated using various $\text{in vitro}$ immunologic tests. Tomites of $\text{I. multifiliis}$ exposed to dilutions of rabbit anti-tetrahymena serum were immobilized in 24 hours. $\text{Tetrahymena}$ in this test system were agglutinated at low dilutions and immobilized at higher dilutions. Using an indirect fluorescent antibody test, both organisms showed fluorescence when treated with either rabbit anti-tetrahymena serum or rabbit anti-tomite serum. In heterologous crosses, titers of 1:1024 were obtaibed using the passive hemagglutination test. These results indicate that an antigenic relationship does exist between these two organisms, cross-reacting antigens appear to be localized on the cilia.     

Natural split-brain?: Lateralized memory for task contingencies in pigeons

The motion aftereffect (MAE) is an illusory motion in the opposite direction after the sudden halt of a prolonged visual moving stimulus. Birds could perceive the MAE as humans and other mammals. The present study was to investigate whether hemispheric asymmetries of visual processes affect this illusion. To this end, pigeons were trained to discriminate grating patterns which moved up, or down or stood still. The transfer tests were conducted under the binocular or monocular viewing condition. The choice behaviors of pigeons under the binocular and right-eye viewing condition (left hemisphere) were highly indicative for the perception of a MAE. However, the animals under the left-eye viewing condition (right hemisphere) did not change their choice patterns according to the different task displayed on the central stimulus key, but always stuck to the default option of pecking the response key ipsilateral to the open eye. We assume that memory for task contingencies were confined to the left hemisphere and could not be reached by the right half brain due to the absence of the corpus callosum.     

Crossed reduction of human motor cortex excitability by 1-Hz transcranial magnetic stimulation

Electrophysiological studies have shown that 1-Hz repetitive transcranial magnetic stimulation (rTMS) of the primary motor area (M1) can produce a local decrease in excitability. Functional imaging data suggest that this change may be bilateral. In normal subjects, we measured motor evoked potential (MEP) amplitude at a series of stimulation intensities in the contralateral M1 before and after 15 min of active or sham rTMS at just above the MEP threshold. The slope of the curve relating MEP amplitude and stimulation intensity was decreased in the unstimulated hemisphere by active but not sham rTMS. This demonstrates that rTMS can condition cortical excitability at a distance of one or more synapses and suggest that decreased excitability to TMS is a correlate of decreased blood flow and metabolism.     

Molecular cloning and analysis of expression of the Leishmania infantum histone H4 genes

In the present work, we describe the sequence, organization and expression of histone H4 genes in the protozoan parasite Leishmania infantum. The predicted L. infantum histone H4 is a polypeptide of 100 amino acids with a molecular mass of 11.5 kDa. Comparison of the amino acid sequence of Leishmania histone H4 with the rest of histone H4 sequences indicates that this is the most divergent sequence reported to date. The genomic distribution analysis of histone H4 genes indicates that there must be up to seven gene copies. A single size-class histone H4 mRNA of 0.6 kb was detected, whose level dramatically decreases from logarithmic to stationary phase. However, the Leishmania histone H4 mRNAs do not decrease in abundance following treatment with inhibitors of DNA synthesis, suggesting a regulation by a replication-independent mechanism.     

The ability of quantitative ultrasound to predict the mechanical properties of trabecular bone under different strain rates

The ability of quantitative ultrasound to predict the mechanical properties of trabecular bone under different strain rates was investigated. Ultrasound velocity (UV) and broadband attenuation (BUA) were measured for 60 specimens of human trabecular bone. Samples were divided into two equal groups and loaded in compression at the strain rates of 0.0004 and 0.08 s⁻¹. The ultimate strength, elastic modulus, and energy absorption capacity were determined for each specimen. Specimens tested at 0.08 s⁻¹ had a mean value of strength 63% higher than the specimens tested at 0.0004 s⁻¹. The elastic modulus and energy absorption capacity were 82% and 42% higher, respectively, for the higher strain rate. UV and BUA were significantly associated with most mechanical properties at both strain rates. All mechanical properties were also correlated strongly with a linear combination of UV and BUA for both the low and high loading rates. The use of ultrasound parameters may provide good clinical means for assessing the resistance of trabecular bone to both low and high energy trauma.