The neural basis of individual differences in mate poaching

This study tested the hypothesis that individual differences in the activity of the orbitofrontal cortex, a region implicated in value-based decision-making, are associated with the preference for a person with a partner, which could lead to mate poaching. During functional magnetic resonance imaging (fMRI), male participants were presented with facial photographs of (a) attractive females with a partner, (b) attractive females without a partner, (c) unattractive females with a partner, and (d) unattractive females without a partner. The participants were asked to rate the degree to which they desired a romantic relationship with each female using an 8-point scale. The participants rated attractive females higher than unattractive females, and this effect was associated with ventral striatum activation. The participants also indicated lower ratings for females with a partner than for females without a partner, and this effect was associated with parietal cortex activation. As predicted, the participants characterized by higher orbitofrontal activity demonstrated a greater willingness to engage in a romantic relationship with females who have a partner compared with females who do not have a partner. These results are the first to provide a possible neural explanation for why certain individuals are willing to engage in mate poaching.     

Involvement of endothelin in the regulation of human vascular tonus. Potent vasoconstrictor effect and existence in endothelial cells

Endothelin, a recently discovered endothelium-derived peptide, has been reported to produce potent vasoconstriction in various vessels of experimental animals. To study the involvement of endothelin in the regulation of vascular tonus in humans, isolated human mesenteric arteries were investigated by both pharmacological and immunohistochemical methods. The vasoconstrictor action of endothelin-1 was examined on ring segments of human mesenteric arteries. Endothelin-1 induced a slowly developing and sustained contraction, with an EC50 value (half-maximal effective concentration) of 2.9 x 10(-9) M, two orders of magnitude smaller than that of norepinephrine (EC50 of 3.9 x 10(-7) M), indicating that the vasoconstrictor action of endothelin-1 is about 100 times more potent than that of norepinephrine. The contractile effect of endothelin-1 was affected neither by adrenergic, cholinergic, histaminergic, nor serotonergic antagonists, nor by inhibitors of arachidonic acid metabolism. The vasoconstrictor response to endothelin-1 was effectively antagonized by nicardipine, a dihydropyridine Ca2+ channel blocker. Endothelin-1 profoundly augmented contractile response to Ca2+ in partially depolarized tissues. Immunohistochemical studies revealed for the first time that endothelin-like immunoreactivity was localized in endothelial cells of human mesenteric artery. The results of the present study indicate that endothelin-1 is one of the most potent vasoconstrictors in the human mesenteric artery and that it induces vasoconstriction via an ultimately accelerating Ca2+ influx through voltage-dependent Ca2+ channels. Since endothelin-1 can be located in human endothelial cells, it may play an important physiological or pathophysiological role.     

Hydrogen peroxide inhibits iodide influx and enhances iodide efflux in cultured FRTL-5 rat thyroid cells

This study describes the effects of hydrogen peroxide on the two iodide transport systems, I influx and I efflux, in the cultured FRTL-5 rat thyroid cells. I influx was measured by the amount of I taken up by the cells during incubation with Na125I and NaI for 7 min, and I efflux was measured by calculating the rate of 125I release from the 125I-loaded cells in the presence and absence of 5 mmol/l H2O2. Exposure to greater than 100 mumol/l H2O2 for 40 min caused a significant inhibition of I influx; the inhibition was reversible and non-competitive with iodide. Thyroid Na+K+ ATPase activity, a major mechanism to drive I influx, decreased by 40% after the cells were exposed to 5 mmol/l H2O2 for 10 min. H2O2 enhanced I efflux only when Ca2+ was present in the medium. The mechanism of an enhanced I efflux by H2O2 appears to be mediated through the elevation of free cytosolic Ca2+ concentration. Our data indicate that H2O2 can affect I transport by inhibiting I influx and enhancing I efflux.     

A case of idiopathic portal hypertension after renal transplantation

A case of idiopathic portal hypertension (IPH) developing after renal transplantation is reported. A 33-year-old Japanese male who had undergone renal transplantation 8 years previously was transferred to our hospital because of hematemesis from ruptured esophageal varices. He had no history of any liver disease before the renal transplantation, but had a history of receiving blood transfusion. Abdominal computed tomography (CT) and ultrasonography revealed marked splenomegaly and collateral channels, but no obliteration which might cause portal hypertension in the hepatic or portal vein. No findings suggestive of hepatitis or liver cirrhosis were found either macroscopically on laparoscopy or by liver biopsy. Light microscopic study of the liver biopsy specimen showed mild periportal fibrosis, inconspicuous portal branches in the most peripheral tracts, but no pseudolobule formation or piecemeal necrosis. However collagen deposition was found in the perisinusoidal space and partly in intercellular space on electron microscopy. We consider that the development of portal hypertension in this case is responsible for the collagen deposition, which may be related to the administration of azathioprine after renal transplantation. There are few reports on IPH after renal transplantation, and it is stressed that a lower amount of azathioprine than previously reported may induce IPH under such conditions.     

Early senile plaques in Alzheimer's disease demonstrated by histochemistry, immunocytochemistry, and electron microscopy

To clarify early pathologic changes in Alzheimer's disease, the brains from two cases from a single family with this disease were examined. A mother who died at age 75 with severe dementia showed an abundance of typical senile plaques, neurofibrillary tangles, and cerebrovascular amyloidosis. The senile plaque and cerebrovascular amyloid were strongly immunoreactive to anti-beta protein antibody. Her son manifested erratic and bizarre behavior, and was suspected of having committed suicide at age 52. His brain weight and macroscopic observations were normal; however, Bielschowsky's silver impregnation and methenamine silver stains showed numerous argyrophilic plaque-like lesions in the neocortex. They were weakly immunolabeled by anti-beta protein antibody, but lacked any abnormal neurites of Congophilic amyloid deposits. These lesions resembled the "type 3" immunoreactive lesions (previously reported by us in Alzheimer's disease and Down's syndrome) which seem to be an early stage of senile plaque formation. These putative early plaque lesions were also examined by methenamine silver electron microscopy, and were seen to consist of loose aggregations of irregular spindle-shaped structures with a heavy deposition of silver grains, with genuine amyloid fibrils not being apparent. It is believed that the accumulation of beta-protein immunoreactive material without amyloid fibril formation might be an initial step in the development of the senile plaque, and that the son, having extensive cortical involvement with type 3 plaque lesions, demonstrated clinical manifestations of less completely developed Alzheimer's disease.     

The remnant preservation technique reduces the amount of bone tunnel enlargement following anterior cruciate ligament reconstruction

Purpose

The aim of the present study was to investigate the correlation between postoperative tunnel enlargement after ACLR and remnant tissue preservation using the hamstring tendon.

Methods

One hundred and ninety-two subjects (male, n = 101; female, n = 91; mean age 27.1) who had undergone double-bundle ACL reconstruction were included in the present study. The patients were divided into two groups: the remnant tissue preservation group (Group R) and the non-remnant tissue preservation group (Group N). Computed tomographic scans of the operated knee were obtained at 2 weeks and 6 months after surgery. The area of the tunnel aperture for the anteromedial femoral tunnel (FAMT), posterolateral femoral tunnel (FPLT), anteromedial tibial tunnel (TAMT), and posterolateral tibial tunnel (TPLT) was measured. The area at 2 weeks after ACLR was subtracted from the area at 6 months after ACLR and then divided by the area at 2 weeks after ACLR. The differences in the outcomes and characteristics of the two groups were evaluated.

Results

Seventy-seven knees were classified into Group R, and 115 knees were classified into Group N. The age, gender, and body mass index did not differ to a statistically significant extent. The percentages of FAMT and TAMT enlargement in Group R were significantly smaller in comparison with Group N (P = 0.003 and P = 0.03, respectively). The percentage of FPLT and TPLT enlargement in the two groups did not differ to a statistically significant extent.

Conclusion

The remnant-preserving technique reduces the amount of bone tunnel enlargement. The present findings indicate the advantages of the remnant-preserving ACLR technique, and therefore the remnant-preserving technique should be recommended.

Level of evidence

II.

     

Usefulness of bone SPECT of the cervical spine : With special reference to separate visualization of the trachea and thyroid cartilage

We applied bone SPECT for the examination of the cervical spine. A three-head rotating gamma camera SPECT system was employed for this study. The SPECT image disclosed 42.7 % of abnormal accumulations in the skeleton not seen with planar imagings. SPECT could separately visualize the trachea and thyroid cartilage and also provided interpretation of abnormality in the anterior part of the vertebral body being difficult with planar imagings only. The trachea cartilage was seen in 55.4% and the thyroid cartilage was seen in 47.3% of patients with anterior neck density in planar imagings. SPECT clarified that marked cervical curvature and diffuse high uptake by the skeleton might cause high intensity of the anterior neck in planar imagings in the case of non-pathological change. We concluded that bone SPECT is a useful diagnostic tool in detecting occult lesion in the skeleton and to rule out extraskeletal accumulations in examination of the cervical spine.     

Growth of Escherichia coli in propofol, lidocaine, and mixtures of propofol and lidocaine

BACKGROUND: Microorganisms grow rapidly in propofol. Extrinsic contamination of propofol is thought to be a source of postoperative sepsis and wound infection. We studied growth of a strain of Escherichia coli in thiopental, propofol, lidocaine, and mixtures of propofol and lidocaine. METHODS: The pathogen was exposed to 2.5% thiopental; 1.0% propofol; 1.0%, 2.0% and 4.0% preservative-free lidocaine; and propofol solutions containing 0.25%, 0.5%, 1.0%, 2.0%, or 4.0% lidocaine for 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h at room temperature, respectively. The inocula from these suspensions were cultured for 48 h at 37 degrees C after the antimicrobial activity of the local anesthetics in the inocula was inactivated by a 1:1000 dilution with distilled water. RESULTS: No organisms grew after exposure to 2.5% thiopental. The exposure of E. coli to propofol increased the colony count to approximately 90 times the control count. The colony counts of E. coli after exposure to 1.0%, 2.0% and 4.0% lidocaine and 0.25%, 0.5%, 1.0%, 2.0% and 4.0% lidocaine in 1.0% propofol were lower than the counts after exposure to 1.0% propofol (P = 0.0048, 0.0027, 0.0003, 0.0503, 0.0188, 0.0080, 0.0044, and 0.0001, respectively). The growth rate of the microorganism was significantly higher in cultures exposed to 1.0% propofol than that in cultures exposed to lidocaine alone or lidocaine-propofol mixtures (P < 0.0001, respectively). CONCLUSION: Lidocaine possesses bacteriostatic activity against E. coli. Addition of lidocaine to propofol confers its bacteriostatic activity to the mixture and may decrease the hazard of infection associated with the extrinsic contamination of propofol.