Pregnenolone sulfate enhances post-training memory processes when injected in very low doses into limbic system structures: the amygdala is by far the most sensitive.

Immediate post-training, stereotactically guided, intraparenchymal administration of pregnenolone sulfate (PS) into the amygdala, septum, mammillary bodies, or caudate nucleus and of PS, dehydroepiandrosterone sulfate, and corticosterone into the hippocampus was performed in mice that had been weakly trained in a foot-shock active avoidance paradigm. Intrahippocampal injection of PS resulted in memory enhancement (ME) at a lower dose than was found with dehydroepiandrosterone sulfate and corticosterone. Intraamygdally administered PS was approximately 10(4) times more potent on a molar basis in producing ME than when PS was injected into the hippocampus and approximately 10(5) times more potent than when injected into the septum or mammillary bodies. ME did not occur on injection of PS into the caudate nucleus over the range of doses tested in the other brain structures. The finding that fewer than 150 molecules of PS significantly enhanced post-training memory processes when injected into the amygdala establishes PS as the most potent memory enhancer yet reported and the amygdala as the most sensitive brain region for ME by any substance yet tested.     

Banana Leaf Surface’s Janus Wettability Transition from the Wenzel State to Cassie–Baxter State and the Underlying Mechanism

Janus wettability plays an important role in certain special occasions. In this study, field emission scanning electron microscopy (FESEM) was used to observe the surface microstructure of banana leaves, the static wettability of the banana leaf surface was tested, and the dynamic response of water droplets falling at different heights and hitting on the adaxial and abaxial sides was studied. The study found that the nanopillars on the adaxial and abaxial sides of the banana leaf were different in shape. The nanopillars on the adaxial side were cone-shaped with large gaps, showing hydrophilicity (Wenzel state), and the heads of the nanopillars on the abaxial side were smooth and spherical with small gaps, showing weak hydrophobicity (Cassie–Baxter state). Banana leaves show Janus wettability, and the banana leaf surface has high adhesion properties. During the dynamic impact test, the adaxial and abaxial sides of the banana leaves showed different dynamic responses, and the wettability of the adaxial side of the banana leaves was always stronger than the abaxial side. Based on the structural parameters of nanopillars on the surface of the banana leaf and the classical wetting theory model, an ideal geometric model around a single nanopillar on both sides of the banana leaf was established. The results show that the established model has high accuracy and can reflect the experimental results effectively. When the apparent contact angle was 76.17°, and the intrinsic contact angle was 81.17° on the adaxial side of the banana leaf, steady hydrophilicity was shown. The abaxial side was similar. The underlying mechanism of Janus wettability on the banana leaf surface was elucidated. This study provides an important reference for the preparation of Janus wettability bionic surfaces and the efficient and high-quality management of banana orchards.     

Virtually Unaltered Permeability-Surface Area Products Imply Little Capillary Recruitment in Brain with Hypoxia

Objective : To test the capillary recruitment hypothesis for the brain with control and hypoxic rats. Methods : Local cerebral blood flow (LCBF) was sharply raised by respiring 10% O₂ (hypoxia). LCBF as well as local influx rate constants (K₁) and permeability-surface area (PS) products of ¹⁴C-antipyrine and ¹⁴C-3-O-methyl-d-glucose (30MG) were estimated for capillary systems in 44 brain areas. Results : With this testing, an increase in PS product would be suggestive of capillary recruitment. In all brain areas, LCBF was increased by 30–90% by hypoxia. Hypoxia modestly raised the influx of antipyrine in brain but did not appreciably alter its PS products. With hypoxia, K₁'s and PS products of 30MG were significantly lowered (5–25%) throughout the brain, and the blood levels of glucose were sizeably raised. The latter increase would diminish the transfer of 30MG across the blood-brain barrier by the hexose transporter because of increased glucose competition. By applying a glucose-concentration correction to the data, the apparent PS product of 30MG for the hypoxic group became equal to that for the controls, which agrees with the antipyrine PS product results. Conclusions : Hypoxia, thus, leads to virtually no increase in PS products and no capillary recruitment in brain, and elevates LCBF mainly, perhaps exclusively, by raising the velocity of flow through already perfused capillaries.     

Coronary microembolization does not induce acute preconditioning against infarction in pigs-the role of adenosine

OBJECTIVE: After coronary microembolization (ME) adenosine is released from ischemic areas of the microembolized myocardium. This adenosine dilates vessels in adjacent nonembolized myocardium and increases coronary blood flow. For ischemic preconditioning (IP) to protect the myocardium against infarction, an increase in the interstitial adenosine concentration (iADO) prior to the subsequent ischemia/reperfusion is necessary. We hypothesized that the adenosine release after ME is sufficient to increase iADO and protect the myocardium against infarction from subsequent ischemia/reperfusion. We have therefore compared myocardial protection by either coronary microembolization or ischemic preconditioning prior to ischemia/reperfusion. METHODS: In anesthetized pigs, the left anterior descending (LAD) was cannulated and perfused from an extracorporeal circuit. In 11 pigs, sustained ischemia was induced by 85% inflow reduction for 90 min (controls). Two other groups of pigs were subjected either to IP (n = 8; 10-min ischemia/15-min reperfusion) or coronary ME (n = 9; i.c. microspheres; 42 microm ?; 3000 x ml(-1) x min inflow) prior to sustained ischemia. Coronary venous adenosine concentration (vADO) and iADO (microdialysis) were measured. Infarct size was determined after 2-h reperfusion by triphenyl tetrazolium chloride staining. RESULTS: In pigs subjected to IP, infarct size was reduced to 2.6 +/- 1.1% (mean +/- S.E.M.) vs. 17.0 +/- 3.2% in controls. iADO was increased from 2.4 +/- 1.3 to 13.1 +/- 5.8 micromol x l(-1) during the reperfusion following IP. In pigs subjected to ME, at 10 min after ME, coronary blood flow (38.6 +/- 3.6 to 53.6 +/- 4.3 ml x min(-1)) and vADO (0.25 +/- 0.04 to 0.48 +/- 0.07 micromol x l(-1)) were increased. However, iADO (2.0 +/- 0.5 at baseline vs. 2.3 +/- 0.6 micromol x l(-1) at 10 min after ME) did not increase. Infarct size induced by sustained ischemia following ME (22.5 +/- 5.2%) was above that of controls for any given subendocardial blood flow. CONCLUSION: ME released adenosine into the vasculature and increased coronary blood flow. The failure of iADO to increase with ME possibly explains the lack of protection against infarction after ME.     

Corticotropin releasing factor distribution in normal and Brattleboro rat brain, and effect of deafferentation, hypophysectomy and steroid treatment in normal animals.

Corticotropin-Releasing Factor (CRF) activity was determined (dispersed pituitary cell assay) in rat median eminence (ME), various hypothalamic nuclei, as well as in entire median basal hypothalamus (MBH) and extra-hypothalamic areas. Highest concentrations were seen in ME, with decreased concentrations noted proceeding dorsally and cephalad from ME. Potency (NIAMDD HE-RP-1, ME reference extract, equivalent to 1.0) estimates were: ME-2.2; arcuate n.-0.88; dorsomedial n.-041; ventromedial n.-0.35; periventricular n.-0.24; hypothalamus-0.05; thalamus-0.01; cortex-0.005. Measurable, but lesser amounts, than in the above cited nuclei, were present in supraoptic and paraventricular nuclei. CRF activity was not measurable in preoptic area, septum, olfactory bulb, striatum, mesencephalon, pons, medulla or cerebellum. Complete hypothalamic deafferentation was accompanied by an increase in CRF activity/mug protein in ME and MBH, associated with decreased AM plasma ACTH and corticosterone concentrations. CRF-like activity in ME and MBH increased following hypophysectomy and after dexamethasone pretreatment. These findings indicate that CRF is mainly synthesized in the ME and surrounding area, and this source of CRF is sensitive to feedback effects and that extrahypothalamic inputs affect CRF release. Female animals had higher ME CRF content than did male animals. Homozygous and heterozygous Brattleboro rats had significantly less CRF in ME and MBH than did control animals, with significant differences also noted between homozygous and heterozygous animals.     

Morphological evidence for direct interaction between arcuate nucleus neuropeptide Y (NPY) neurons and gonadotropin-releasing hormone neurons and the possible involvement of NPY Y1 receptors.

Neuropeptide Y (NPY) neurons in the arcuate nucleus of the hypothalamus (ARH) have been shown to play an important role in modulating LH secretion. One mechanism by which the ARH NPY system may regulate LH secretion is by modulating GnRH neuronal function. Thus, the present study examined whether the ARH NPY system provided direct input to GnRH cell bodies in the preoptic area (POA), as well as to their nerve terminals in the median eminence (ME). The possible involvement of the NPY Y1 receptor subtype in mediating the effects of NPY was also investigated. Lactating rats were used in these studies because they have increased hypothalamic NPY content, especially in the ARH/ME areas, making it easier to detect NPY fibers and terminals. The anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L), was iontophoresed into the ARH of lactating rats; and triple-label immunofluorescence was performed, with the aid of confocal microscopy, to visualize NPY, PHA-L, and GnRH. GnRH cell bodies were found scattered throughout the organum vasculosum laminae terminalis (OVLT)/POA region, and NPY/ PHA-L double-labeled fibers were found in very close proximity to numerous GnRH perikarya. In the ME, double-labeled NPY/PHA-L fibers were found in the inner and external zones, and they were found in close proximity to GnRH neuronal fibers. Using a NPY Y1 specific antibody, double-label immunofluorescence was performed to examine whether the Y1 receptor subtype was expressed in GnRH neurons. No convincing Y1-positive staining was found in GnRH cell bodies in the OVLT/POA region. However, abundant Y1-positive fiber and cell staining were observed throughout the region, and Y1-positive fibers were found in close apposition to GnRH cell bodies. In contrast, numerous GnRH nerve fibers and terminals in both the OVLT and ME were colocalized with Y1-positive staining. The results of this study suggest that ARH NPY neurons come in close contact with GnRH neurons and may provide direct input to both GnRH cell bodies in the POA region and to their nerve terminals in the ME. The Y1 receptor subtype may be directly involved in NPY modulation of GnRH secretion from its nerve terminals.     

Decreased presence of perforated synapses in a triple-transgenic mouse model of Alzheimer's disease

Transgenic mouse models of Alzheimer's disease (AD) are useful tools to further our understanding of AD genotype-phenotype interaction. The triple transgenic mice harboring mutant forms of APP/PS1/Tau (3xTg-AD) exhibit beta-amyloid (Abeta) plaques (by 6 months of age) as well as neurofibrillary tangles (by 10-12 months of age). In this study, we characterized morphological alterations of hippocampal synapses obtained from 13-month-old 3xTg-AD and age-matched control (PS1-KI) mice. Numeric density of synapses (Nv, number of junctions/microm(3) of tissue), average synaptic contact area (S), and synaptic surface density (Sv, total synaptic contact area/microm(3) of tissue) were investigated by morphometric methods in the AD vulnerable CA1 pyramidal cell layer. Comparisons between 3xTg-AD and control mice showed no statistically significant differences in any of the three parameters; however, a significant decrease (by 28.5%) in the fraction of perforated junctional areas (PS) was observed in the 3xTg-AD mice. As PS is a reliably indirect index of synaptic plasticity, a decreased PS number might represent a subtle and early sign of synaptic dysfunction occurring in the 3xTg-AD mice, and lend support to the hypothesis that altered synaptic function is a critical feature of AD.     

Use of horseradish peroxidase to identify hindbrain sites that influence gastric motility in the cat

To identify hindbrain sites that influence gastric motility, we administered multiple injections of horseradish peroxidase into the anterior surface of the antrum near the lesser curvature in 3 cats, and used light microscopy to identify horseradish peroxidase-positive neurons in the hindbrain. Retrogradely labeled neurons were found evenly distributed on both sides in the dorsal motor nucleus of the vagus. Labeling extended from 2.5 mm rostral to 2.0 mm caudal to the obex. Labeled neurons were not localized to a specific region of the dorsal motor nucleus of the vagus: no labeling was observed in the nucleus ambiguus or in the nuclei of the solitary tract. Electrical stimulation of the dorsal motor nucleus of the vagus in the area with the greatest number of labeled cell bodies was performed in 4 cats while monitoring antral motility, arterial pressure, and heart rate. Stimulation elicited pronounced antral contractions but no changes in arterial pressure or heart rate. These data demonstrate that the retrograde neuronal tracing technique permits localization of central nervous system sites that specifically influence gastric function.     

The prevalence of anti-Toxoplasma gondii antibodies among abattoir workers in Lublin

Abattoir workers are occupationally exposed to Toxoplasma gondii by the contact with raw meat. One hundred and seven abattoir workers from the Meat Factory in Lublin were examined for the presence of anti-Toxoplasma antibodies. Sixty-one blood donors were also tested as the reference group. Sera from workers and referents were tested by direct agglutination with 2-mercaptoethanol (DA-2ME), and also by ELFA IgG and ELFA IgM tests (Vidas Toxo IgM, Vidas Toxo IgG, bioMerieux, France). In the workers group, out of 107 tested sera, 70 were found positive (65.4%). The highest percentage of seropositive results was found in the Cured Meat Division--76.2%. In the Meat Production Division 66.6% of seropositive results were found, and in the Slaughter Division--46.1%. Three persons with the presence of IgM antibodies were found in the Cured Meat Division. In the reference group, 34 out of 61 sera (55.7%) were positive. The difference in seropositivity between Cured Meat Division workers and reference group was statistically significant (p < 0.05). The high percentage of seropositive reactions among the workers of Cured Meat Division and the presence of persons in early stage of invasion suggest an increased risk of exposure to T. gondii in this section.     

Immunocytochemical delineation of thyrotrophic area: origin of thyrotropin-releasing hormone in the median eminence

To identify the specific thyrotropin-releasing hormone (TRH)-containing neurons projecting to the median eminence (ME), a retrograde tracing method with horseradish peroxidase (HRP) was combined with immunocytochemical staining for TRH. Three days after HRP injection restricted to the ME, several TRH-positive neuronal perikarya were found to contain HRP. Such double-stained cells were exclusively distributed in the anterior parts of the periventricular nucleus and the most medial parts of the paraventricular nucleus. Few double-stained cells were observed in other parts of the brain examined. The present observations appear to demonstrate that the specific TRH neurons projecting to the ME are located along the border of the third ventricle, anterior to the ME.     

Sertoli cells inhibited apoptosis of pachytene spermatocytes and round spermatids.

Apoptosis in the testis represents an important physiological mechanism that regulates the number of germ cells in the seminiferous epithelium. This apoptosis is believed to be regulated by many factors, including growth factors and cytokines, which appear to suppress apoptosis of the germ cells. In this study, we examined the roles of Sertoli cells on the regulation of pachytene spermatocyte (PS) and round spermatid (RSd) apoptosis with either a co-culture trans-well system or a direct contact system. Apoptosis was detected by low molecular weight DNA fragmentation assay, in situ end labeling, and an LDH assay. In addition, the level of Bcl-2, Bax, and ICE mRNAs in PS and RSd by Northern blot analysis. When PS and RSd were cultured with Sertoli cells in either a trans-well system or direct contact system, the extent of apoptotic DNA fragmentation and LDH level were both significantly lower than those control values. TUNEL staining also revealed the inhibition of apoptosis of PS and RSd when they were cultured with Sertoli cells compared with controls (p <0.05). Moreover, the extent of apoptotic DNA fragmentation and LDH level were significantly lower in the direct contact system than in the trans-well system. TUNEL staining also demonstrated a more decrease in apoptosis of PS and RSd in the direct contact system compared with the trans-well system (p < 0.05). PS and RSd cultured with Sertoli cells exhibited an increase in Bcl-2 mRNA, whereas those cultured with serum-free medium did not show any change. The levels of Bax and ICE mRNAs decreased in PS and RSd cultured with Sertoli cells in comparison with control values. These results suggest that Sertoli cells can prevent apoptosis of germ cells, and that the effect of Sertoli cells on germ cells is mediated by cell to cell interaction or, remote effects of inhibitory factors on apoptosis.     

Effect of electrical stimulation of the ventromedial nucleus and the dorsomedial nucleus on the activity of tuberoinfundibular dopaminergic neurons

Perikarya and terminals of tuberoinfundibular dopaminergic (TIDA) neurons are located in the arcuate nucleus (ARN) and in the median eminence (ME), respectively. Dopamine (DA) released from TIDA terminals in the ME inhibits prolactin secretion from the anterior pituitary. Anatomical studies have described the sources of afferents to ARN and ME, but not to TIDA neurons per se. The ventromedial nucleus (VMN) and the dorsomedial nucleus (DMN) of the hypothalamus project to ARN and ME and have a role in prolactin regulation. In the present study, VMN and DMN were investigated as possible sources of TIDA afferents. Alterations in the activity of TIDA neurons were estimated by measuring plasma concentrations of prolactin and the rates of DA synthesis (3,4-dihydroxyphenylalanine - DOPA - accumulation after administration of the decarboxylase inhibitor NSD 1015) and metabolism (concentrations of the DA metabolite 3,4-dihydroxyphenylacetic acid - DOPAC) in the ME following electrical stimulation of ARN, VMN, and DMN in ovariectomized female rats. Thirty minutes of bilateral stimulation of ARN or DMN increased DOPA accumulation in the ME; stimulation of the VMN had no effect. 5-Hydroxytryptamine synthesis in the ME was unaffected by stimulation of any region. Plasma prolactin levels declined during DMN stimulation, varying with the frequency and duration of the electrical stimulus. DA metabolism within TIDA neurons increased with DMN stimulation, as evidenced by increased DOPAC concentrations in the ME. In females whose basal TIDA activity has been increased by haloperidol treatment or decreased by bromocriptine treatment, DMN stimulation was still able to increase DOPA accumulation in the ME. The present data suggest the presence of stimulatory TIDA afferents originating from or passing through the DMN.     

How do we determine the safe limit of hepatectomy based on multiple crucial factors?

This study reports how to prevent posthepatectomy liver failure and the crucial factors in evaluation of hepatic reserve. In 1980, we established a prediction score (PS) system for predicting the safe limit of hepatectomy. We used a multiple regression equation: Y(PS)=?84.6+0.933X₁+1.12X₂+1.0X₃, where X₁ is computed tomographic scan-estimated resection rate (%), X₂ is ICG retention rate (%) and X₃ is patient's age. Of the clinically available liver function tests, ICG retention rate or clerance had the highest correlation with biomechanically estimated liver consistency and morpho-metrically estimated collagen content, both of which affect liver regenerative capacity. With the further accumulation of a subsequent 10 years' experience (1981—1990), the system was refined. If a PS greater than 55 was given to a planned resection part it was classified as a risky zone; a PS of 45—55, as a borderline zone; and a PS less than 45, as a safe zone. In the borderline zone, the pattern of the glucose tolerance curve and the presence or absence of coexistent liver disease were determined to be additional prognostic factors. Even if patients were assessed as being in the safe zone by reducing resection range, patients with disturbed glucose tolerance, lower platelet count, and higher ICG retention rate were found to be at a high risk for liver failure secondary to septic postoperative complications. Mortality by liver failure has been reduced with the use of these systems, from 16% before 1980 to 6.3% (24/376, 1981—1990) and to 0.9% (2/202, 1991—1995). Avoidance of excessive resection unmatched to individual hepatic reserve and avoidance of septic complications are mandatory in patients with a limited safe margin of hepatic reserve.     

Benefits of Artificially Induced Pleural Effusion and/or Ascites for Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma Located on the Liver Surface and in the Hepatic Dome

Background/Aims: Radiofrequency ablation (RFA) with artificial pleural effusion and/or artificial ascites has recently been recognized as a useful device for the treatment of hepatocellular carcinoma (HCC). However, the indication of this technique is unclear and its therapeutic efficacy is undetermined. Methodology: We decided the precise indication for the use of artificial infusion. Artificial pleural effusion was indicated for tumors located on the dorsal side of the liver surface in the right lobe. Artificial ascites were indicated for (i) tumors located on the ventral side of the liver surface in the right lobe; (ii) tumors that could not be completely visualized but located near the liver surface in the right lobe; and (iii) tumors on the liver surface and adjacent to organs. Results: The total local recurrence rates at 1 and 2 years were 4% and 22%, respectively. The estimated survival rates of 32 na?ve patients at 1 and 3 years were 90% and 78%, respectively. The local recurrence rates of a tumor size of <3 cm and >3 cm at 2 years were 22% and 17%, respectively. Conclusions: RFA with artificial pleural effusion and/or ascites is effective for tumors located on the liver surface and in the hepatic dome.     

Refined HLA-DPB1 mismatch with molecular algorithms predicts outcomes in hematopoietic stem cell transplantation

HLA-DPB1 mismatches between donor and recipient are commonly seen in allogeneic hematopoietic stem cell transplantation from an unrelated donor. HLA-DPB1 mismatch, conventionally determined by the similarity of the T-cell epitope (TCE), is associated with an increased risk of acute graft-versus-host disease (GVHD) and a decreased risk of disease relapse. We investigated the clinical impact of HLA-DPB1 molecular mismatch quantified by mismatched eplets (ME) and the Predicted Indirectly Recognizable HLA Epitopes Score (PS) in a cohort of 1,514 patients receiving hematopoietic stem cell transplants from unrelated donors matched at HLA-A, -B, -C, -DRB1/3/4/5, and - DQB1 loci. HLA-DPB1 alloimmunity in the graft-versus-host direction, determined by high graft-versus-host ME/PS, was associated with a reduced risk of relapse (hazard ratio [HR]=0.83, P=0.05 for ME) and increased risk of grade 2-4 acute GVHD (HR=1.44, P<0.001 for ME), whereas high host-versus-graft ME/PS was only associated with an increased risk of grade 2-4 acute GVHD (HR=1.26, P=0.004 for ME). Notably, in the permissive mismatch subgroup classified by TCE grouping, high host-versus-graft ME/PS was associated with an increased risk of relapse (HR=1.36, P=0.026 for ME) and grade 2-4 acute GVHD (HR=1.43, P=0.003 for PS-II). Decision curve analysis showed that graftversus- host ME outperformed other models and provided the best clinical net benefit for the modification of acute GVHD prophylaxis regimens in patients with a high risk of developing clinically significant acute GVHD. In conclusion, molecular assessment of HLA-DPB1 mismatch enables separate prediction of host-versus-graft or graft-versus-host alloresponse quantitatively and allows further refinement of HLA-DPB1 permissiveness as defined by conventional TCE grouping.     

中国西南地区儿童土源性线虫感染及影响因素调查

目的 了解中国西南贫困地区儿童土源性线虫感染情况和主要影响因素, 为制定土源性线虫病防治措施提供依据。方法 采用改良加藤厚涂片法对受检儿童粪便进行病原学检查, 其中部分儿童进行透明胶纸肛拭法检查蛲虫卵。采用问卷调查和Probit 估计多元统计方法, 分析儿童服药驱虫、 个体特征、 饮食卫生习惯和家庭特征等16个相关因素对土源性线虫感染的影响。结果 共粪检1 707名儿童, 土源性线虫感染率为22.2%, 其中蛔虫、 钩虫、 鞭虫感染率分别为16.9%、 3.8%和6.6%, 且以蛔虫感染率和感染度为最高; 蛲虫检查495名, 感染率为5.1%。Probit 估计多元统计显示, 兄弟姐妹数量、 母亲受教育程度、 饮用生水、 饲养畜禽等4个因素差异均有统计学意义 （P均 < 0.05）。其中, 母亲受教育程度能降低土源性线虫感染率, 边际效应为-0.074; 兄弟姐妹数量、 饮用生水和饲养畜禽均能提高土源性线虫感染率, 边际效应分别为 0.028、 -0.112和0.080。结论 我国西南贫困地区儿童土源性线虫感染率仍然较高, 且以蛔虫感染为主; 改变儿童饮用生水的不良卫生习惯、 家庭饲养畜禽习惯和针对其母亲开展寄生虫病防治知识的健康教育, 对儿童土源性线虫病的预防和控制具有重要意义。     

Neural latencies across auditory cortex of macaque support a dorsal stream supramodal timing advantage in primates

Sensory systems across the brain are specialized for their input, yet some principles of neural organization are conserved across modalities. The pattern of anatomical connections from the primate auditory cortex to the temporal, parietal, and prefrontal lobes suggests a possible division into dorsal and ventral auditory processing streams, with the dorsal stream originating from more caudal areas of the auditory cortex, and the ventral stream originating from more rostral areas. These streams are hypothesized to be analogous to the well-established dorsal and ventral streams of visual processing. In the visual system, the dorsal processing stream shows substantially faster neural response latencies than does the ventral stream. However, the relative timing of putative dorsal and ventral stream processing has yet to be explored in other sensory modalities. Here, we compare distributions of neural response latencies from 10 different areas of macaque auditory cortex, confirmed by individual anatomical reconstructions, to determine whether a similar timing advantage is found for the hypothesized dorsal auditory stream. Across three varieties of auditory stimuli (clicks, noise, and pure tones), we find that latencies increase with hierarchical level, as predicted by anatomical connectivity. Critically, we also find a pronounced timing differential along the caudal-to-rostral axis within the same hierarchical level, with caudal (dorsal stream) latencies being faster than rostral (ventral stream) latencies. This observed timing differential mirrors that found for the dorsal stream of the visual system, suggestive of a common timing advantage for the dorsal stream across sensory modalities.     

Revisiting the “leading edge” of hospital privacy curtains in the medical intensive care unit

BackgroundPrivacy curtains within medical intensive care unit (MICU) rooms are a potential contributor to health care associated infections. The “leading edge” of a hospital curtain, estimated to be the edge most frequently touched, likely plays a role in health care associated infections at hospitals. The aims of this study were to (1) compare the bacterial load of the edge vs the middle of curtains in the MICU, and (2) determine the identity and distribution of relevant pathogens colonizing them.MethodsThe edge and middle sections of 8 curtains in MICU rooms (4 contact precaution and 4 noncontact precaution) were sampled for culture on patient and staff sides. Bacterial loads of edges and middles were compared. Select isolates were further analyzed for species identification.ResultsThere was a statistically significant difference for the contact (t = 2.10, P = .047) and noncontact (t = 2.62, P = .016) rooms, with the edges having a significantly higher median than the middles. Pathogens such as methicillin-resistant Staphylococcus aureus, Enterococcus, Klebsiella, and Acinetobacter were found on the curtains, though at lower rates than in previous studies. Opportunistic fungi were also found on all curtains.ConclusionsResults of this study confirm that hospital curtains, most notably the edge but also the middle, are contaminated with pathogens, and that these areas are frequently touched by health care workers in between hand hygiene.     

The annual risk of tuberculous infection in the eastern zone of India.

SETTING: Rural and urban areas of eight selected districts in the eastern zone of India. OBJECTIVES: To estimate the annual risk of tuberculous infection (ARTI). STUDY DESIGN: A community-based, cross-sectional tuberculin survey was conducted among children aged 1-9 years residing in a sample of rural and urban areas. Stratified two-stage cluster sampling was adopted for selection of rural and urban clusters. A total of 40964 children in 515 clusters underwent tuberculin testing and reading with 1TU PPD RT23 with Tween 80; the maximum transverse diameter of induration was measured about 72 h after the test. RESULTS: A bacille Calmette-Gúerin (BCG) scar was observed in 51.5% of the test-read children. The frequency distribution of tuberculin reaction size among 19332 children without BCG scar was found to be bimodal, with the mode of reactions attributable to infection with tubercle bacilli at 20 mm. The prevalence of infection was estimated as 6.9%. The ARTI computed from the estimated prevalence was 1.3%. Children residing in the urban areas were found to be at a significantly higher risk of infection than those residing in rural areas. CONCLUSION: The high rate of ARTI in the eastern zone of India suggests a need for committed, sustained action in provision of quality tuberculosis control services.     

Epoxygenase products of arachidonic acid are endogenous constituents of the hypothalamus involved in D2 receptor-mediated, dopamine-induced release of somatostatin

The epoxyeicosatrienoic acids (EETs) were discovered as products of a cyclooxygenase/lipoxygenase-independent, cytochrome P-450 catalyzed metabolism of arachidonic acid (AA) termed the "epoxygenase" pathway. The rat hypothalamus is able to synthesize EETs from exogenous AA, and 5,6-EET has been found to release the neuropeptide somatostatin (SRIF) from hypothalamic nerve terminals of the median eminence (ME). In the present study, hypothalami from male rats were examined for the presence of endogenous EETs, using chemical, chromatographic, and mass spectral analysis procedures. The samples were initially separated in a C18 Sepralyte column, fractionated on TLC plates, and purified by reverse phase HPLC. Thereafter, they were esterified (pentafluorobenzyl esters) and subjected to negative ion chemical ionization/gas chromatography (GC)/mass spectral (MS) analysis. The GC retention time and the MS fragmentation patterns revealed the presence of a mixture of 8,9-, 11,12- and 14,15-EETs; instability of 5,6-EET during the isolation protocol precluded its identification. Total hypothalamic EET concentration was estimated to be 120 ng/g wet tissue. The 8,9-regiosomer released SRIF from ME nerve terminals with an ED50 of 5 x 10(-12) M; Dopamine (DA) and the D2 receptor agonist PPHT, but not the D1 receptor agonist SKF-38393, induced SRIF release from the ME. This effect was blocked by clotrimazole and ketoconazole, two inhibitors of microsomal cytochrome P-450 function and AA epoxygenase in particular. In contrast, the inhibitors failed to affect the increase in SRIF release induced by 8,9-EET. These results indicate that: 1) in addition to cyclooxygenase and lipoxygenase products, epoxygenase metabolites of AA are endogenous compounds of the hypothalamus, and 2) EETs may mediate the increase in SRIF release from hypothalamic neurons induced by the interaction of DA with D2 receptors.