Possible association between nonsynonymous polymorphisms of the anaplastic lymphoma kinase (ALK) gene and schizophrenia in a Japanese population

We examined, for the first time, the possible association between schizophrenia and the anaplastic lymphoma kinase (ALK) gene which plays an important role in neurodevelopment. When two nonsynonymous polymorphisms (Arg1491Lys and Glu1529Asp) were examined, there were significant differences in genotype and allele distributions between patients and controls. Individuals homozygous for the minor allele (1491Lys-1529Asp) were more common in patients than in controls (p = 0.0064, odds ratio 2.4, 95% CI 1.3-4.6). These results suggest that genetic variations of the ALK gene might confer susceptibility to schizophrenia.

Cellular immune responses to feline immunodeficiency virus (FIV) induced by dual-subtype FIV vaccine

Vaccine-induced T cell responses to FIV were assessed by measuring FIV-specific cytokine and cytotoxic-effector molecule production. A total of 22 cats at 10-12 weeks of age received either dual-subtype FIV vaccine (n=12), uninfected cell lysate (n=5) consisting of cells used to produce vaccine viruses, or no immunization (n=5). Significant increases in mRNA and protein production of T-helper 1 (Th1) cytokines (IL-2, IFNgamma), mRNA production of a cytotoxic-effector molecule (perforin), and lymphoproliferation response were observed in peripheral blood mononuclear cells (PBMC) from dual-subtype FIV-vaccinated cats after in vitro stimulation with inactivated FIV. In contrast, no statistically significant increase in FIV-stimulated mRNA production of Th2 cytokines (IL-4, IL-6) or other cytotoxic-effector molecules (TNFalpha, FasL) was observed in the PBMC from dual-subtype vaccinated cats. Moreover, no FIV-specific increases in the IFNgamma, IL-2, and perforin mRNA productions and in the IFNgamma bioactivity and lymphoproliferation responses were observed in the PBMC from cell-immunized cats. These observations suggest that IFNgamma induction, lymphoproliferation, and significant portion of IL-2 and perforin productions in the PBMC from dual-subtype vaccinated cats are clearly specific for viral antigens. Overall, dual-subtype FIV vaccine elicited strong Th1 response (IFN(, IL-2), which may contribute to the vaccine protection by enhancing the perforin-mediated cytotoxic-cell activity against FIV.

Individual trait anxiety levels characterizing the properties of zen meditation

Meditation is a specific consciousness state in which deep relaxation and increased internalized attention coexist. There have been various neurophysiological studies on meditation. However, the personal predispositions/traits that characterize the properties of meditation have not been adequately studied. We analyzed changes in neurophysiological parameters [EEG coherence and autonomic nervous activity using heart rate variability (HRV) as an index] during Zen meditation, and evaluated the results in association with trait anxiety (assessed by Spielberger's State-Trait Anxiety Inventory) in 22 healthy adults who had not previously practiced any form of meditation. During meditation, in terms of mean values in all subjects, an increase in slow alpha interhemispheric EEG coherence in the frontal region, an increase in high-frequency (HF) power (as a parasympathetic index of HRV), and a decrease in the ratio of low-frequency to HF power (as a sympathetic index of HRV) were observed. Further evaluation of these changes in individuals showed a negative correlation between the percent change (with the control condition as the baseline) in slow alpha interhemispheric coherence reflecting internalized attention and the percent change in HF reflecting relaxation. The trait anxiety score was negatively correlated with the percent change in slow alpha interhemispheric coherence in the frontal region and was positively correlated with the percent change in HF. These results suggest that lower trait anxiety more readily induces meditation with a predominance of internalized attention, while higher trait anxiety more readily induces meditation with a predominance of relaxation.

Neural substrates participating in acquisition of facial familiarity: an fMRI study

The amygdala is related to recognition of faces and emotions, and functional magnetic resonance imaging (fMRI) studies have reported that the amygdala is habituated over time with repetition of facial stimuli. When subjects are presented repeatedly with unfamiliar faces, they come to gradually recognize the unfamiliar faces as familiar. To investigate the brain areas participating in the acquisition of familiarity to repeatedly presented unfamiliar faces, we conducted an fMRI study in 16 healthy subjects. During the task periods, the subjects were instructed to see presented unfamiliar faces repeatedly and to judge whether the face was male or female or whether the face had emotional valences. The experiment consisted of nine sessions. To clarify the brain areas that showed increasing or decreasing activation as the experimental session proceeded, we analyzed the fMRI data using specified linear covariates in the face recognition task from the first session to the ninth session. Imaging data were investigated on a voxel-by-voxel basis for single-group analysis according to the random effect model using Statistical Parametric Mapping. The bilateral posterior cingulate cortices showed significant increases in activity as the experimental sessions proceeded, while the activation in the right amygdala and the left medial fusiform gyrus decreased. Thus, the posterior cingulate cortex may play an important role in the acquisition of facial familiarity.

Abnormal nocturnal blood pressure fall in senile-onset depression with subcortical silent cerebral infarction

Recent studies have shown that the complication rate of silent cerebral infarction (SCI) in patients with geriatric depression increases with the age at the onset of depression. This study investigated the cardiovascular factors involved in the development of SCI in geriatric depression. Thirty-six patients with geriatric depression were classified according to the age at onset into 16 who developed depression at the age of <50 years (early-onset group) and 20 who developed depression at the age of > or =50 years (late-onset group). The incidence of SCI assessed by subcortical hyperintensity on MRI images, office blood pressure (BP), nocturnal systolic BP fall pattern examined by 24-hour ambulatory BP monitoring, and the severity of carotid atherosclerosis examined by B-mode ultrasonography were compared between the two groups. Furthermore, the association between the presence or absence of SCI and the nocturnal systolic BP fall pattern or the severity of carotid atherosclerosis was evaluated. The SCI complication rate was higher in the late-onset group (55.0%) than in the early-onset group (18.7%). The office BP and mean 24-hour BP did not differ significantly between the two groups. Abnormal nocturnal systolic BP fall patterns were observed in 85.0% (nondipper type showing a fall of <10% in 60.0%, extreme-dipper type showing a fall of > or =20% in 25.0%) in the late-onset group, which was significantly higher than the incidence in the early-onset group (18.7%). No significant difference was observed in any parameter of carotid atherosclerosis between the two groups. In addition, the patients with SCI more frequently showed abnormal nocturnal systolic BP fall patterns than those without SCI. These results suggest that abnormal nocturnal BP fall patterns appear to be involved in the development of SCI in senile-onset depression.

Central pontine myelinolysis associated with hypokalaemia in anorexia nervosa

A 31-year-old man was admitted to hospital with of anorexia, binge eating, and self induced vomiting. On admission, he showed a pronounced low weight and disturbance of the body image and was diagnosed as having anorexia nervosa. In addition, electrolyte abnormalities, mainly hypokalaemia, and increased serum renin and aldosterone concentrations were recorded, suggesting pseudo-Bartter syndrome as a complication. Under frequent monitoring of the serum potassium and sodium concentrations, serum electrolytes were gradually corrected, but brain magnetic resonance imaging revealed reversible central pontine myelinolysis (CPM). Although attention has been mainly paid to the association of CPM with rapid correction of hyponatraemia and abnormal osmolality, this case report strongly suggested the involvement of hypokalaemia in the pathogenesis of CPM.

Differential amygdala response during facial recognition in patients with schizophrenia: an fMRI study

Human lesion or neuroimaging studies suggest that amygdala is involved in facial emotion recognition. Although impairments in recognition of facial and/or emotional expression have been reported in schizophrenia, there are few neuroimaging studies that have examined differential brain activation during facial recognition between patients with schizophrenia and normal controls. To investigate amygdala responses during facial recognition in schizophrenia, we conducted a functional magnetic resonance imaging (fMRI) study with 12 right-handed medicated patients with schizophrenia and 12 age- and sex-matched healthy controls. The experiment task was a type of emotional intensity judgment task. During the task period, subjects were asked to view happy (or angry/disgusting/sad) and neutral faces simultaneously presented every 3 s and to judge which face was more emotional (positive or negative face discrimination). Imaging data were investigated in voxel-by-voxel basis for single-group analysis and for between-group analysis according to the random effect model using Statistical Parametric Mapping (SPM). No significant difference in task accuracy was found between the schizophrenic and control groups. Positive face discrimination activated the bilateral amygdalae of both controls and schizophrenics, with more prominent activation of the right amygdala shown in the schizophrenic group. Negative face discrimination activated the bilateral amygdalae in the schizophrenic group whereas the right amygdala alone in the control group, although no significant group difference was found. Exaggerated amygdala activation during emotional intensity judgment found in the schizophrenic patients may reflect impaired gating of sensory input containing emotion.

Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted 8B spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5%)(-1.4%) of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3%)(-1.2%). A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.

Direct evidence for neutrino flavor transformation from neutral-current interactions in the Sudbury Neutrino Observatory

Observations of neutral-current nu interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard 8B shape, the nu(e) component of the 8B solar flux is phis(e) = 1.76(+0.05)(-0.05)(stat)(+0.09)(-0.09)(syst) x 10(6) cm(-2) s(-1) for a kinetic energy threshold of 5 MeV. The non-nu(e) component is phi(mu)(tau) = 3.41(+0.45)(-0.45)(stat)(+0.48)(-0.45)(syst) x 10(6) cm(-2) s(-1), 5.3sigma greater than zero, providing strong evidence for solar nu(e) flavor transformation. The total flux measured with the NC reaction is phi(NC) = 5.09(+0.44)(-0.43)(stat)(+0.46)(-0.43)(syst) x 10(6) cm(-2) s(-1), consistent with solar models.

MRI white matter hyperintensities, (1)H-MR spectroscopy and cognitive function in geriatric depression: a comparison of early- and late-onset cases

BACKGROUND AND OBJECTIVES Geriatric depression is often thought to differ from that at other times of adulthood. Recently, several studies have shown that the incidence of white matter hyperintense lesions identified by brain MRI is higher in patients with geriatric depression than in healthy elderly subjects, but a consensus has not yet been reached on the relationship between the severity of white matter lesions and either cognitive impairment or depressive symptoms.

METHOD

Forty-seven patients aged 50 to 75 years with major depression were divided into two groups based on age at onset of depression: early-onset (< 50 years) group (20 patients; mean age, 62.7 +/- 6.7) and late-onset (> or =50 years) group (27 patients; mean age, 65.6 +/- 5.4). The severity of hyperintense white matter lesions on MRI was classified by region, then a proton magnetic resonance spectroscopy ((1)H-MRS) focusing on the white matter of the frontal lobes, multidimensional neuropsychological tests and evaluation of depressive symptoms were conducted.

RESULTS

The severity of the deep white matter lesions, the deterioration of cognitive function related to subcortical/frontal brain system and clinician-rated depressive symptoms were all more pronounced in the late-onset group compared with those in the early-onset group. It was further observed that the more severe the deep white matter lesions, the lower the levels of N-acetylaspartate/creatine. With the age of onset as the covariate, the patients with moderate deep white matter lesions had more pronounced cognitive impairment and clinician-rated depressive symptoms than those with none and/or mild lesions.

CONCLUSION

These results suggest that subcortical/frontal type cognitive impairment and the persistence of depressive symptoms in geriatric depression is related to moderate deep white matter lesions more often complicated in the late-onset group. The (1)H-MRS findings were suggested to be a useful indicator of neuronal/axonal loss in the white matter of the frontal lobes which precedes cognitive impairment.

Quantitative evaluation of magnetic resonance imaging of deep white matter hyperintensity in geriatric patients by multifractal analysis

Fractal analysis has played an important role in various fields such as physics, biology and medicine. Recently, multifractal analysis based on generalized concepts of fractals has been applied to biological tissues composed of complex structures. Deep white matter hyperintensity (DWMH) on brain magnetic resonance imaging (MRI) is more often observed in patients with geriatric depression than in healthy elderly subjects, and its clinical significance is receiving attention. We applied multifractal analysis to white matter images on brain T2-weighted MRI in 62 patients with geriatric depression (50-75 years). The local fractal dimensions, alpha(max) and alpha(min), which serve as indices of complexity, and their difference, alpha(max) - alpha(min), were closely correlated with the macroscopic grading according to Fazekas classification, suggesting that multifractal analysis is useful for quantitative evaluation of DWMH on MRI.

Neural interaction of the amygdala with the prefrontal and temporal cortices in the processing of facial expressions as revealed by fMRI

Some involvement of the human amygdala in the processing of facial expressions has been investigated in neuroimaging studies, although the neural mechanisms underlying motivated or emotional behavior in response to facial stimuli are not yet fully understood. We investigated, using functional magnetic resonance imaging (fMRI) and healthy volunteers, how the amygdala interacts with other cortical regions while subjects are judging the sex of faces with negative, positive, or neutral emotion. The data were analyzed by a subtractive method, then, to clarify possible interaction among regions within the brain, several kinds of analysis (i.e., a correlation analysis, a psychophysiological interaction analysis and a structural equation modeling) were performed. Overall, significant activation was observed in the bilateral fusiform gyrus, medial temporal lobe, prefrontal cortex, and the right parietal lobe during the task. The results of subtraction between the conditions showed that the left amygdala, right orbitofrontal cortex, and temporal cortices were predominantly involved in the processing of the negative expressions. The right angular gyrus was involved in the processing of the positive expressions when the negative condition was subtracted from the positive condition. The correlation analysis showed that activity in the left amygdala positively correlated with activity in the left prefrontal cortex under the negative minus neutral subtraction condition. The psychophysiological interaction revealed that the neural responses in the left amygdala and the right prefrontal cortex underwent the condition-specific changes between the negative and positive face conditions. The right amygdaloid activity also had an interactive effect with activity in the right hippocampus and middle temporal gyrus. These results may suggest that the left and right amygdalae play a differential role in effective processing of facial expressions in collaboration with other cortical or subcortical regions, with the left being related with the bilateral prefrontal cortex, and the right with the right temporal lobe.

Serial MRI and (1)H-MRS of Wernicke's encephalopathy: report of a case with remarkable cerebellar lesions on MRI

Before and after the administration of thiamine (vitamin B(1)), MRI and proton magnetic resonance spectroscopy ((1)H-MRS) were serially performed in a patient with Wernicke's encephalopathy demonstrating remarkable cerebellar lesions on MRI. Before thiamine administration, high signal intensities were observed in the thalamus around the third ventricle and in the superior portion of the cerebellar vermis and hemisphere on fluid-attenuated inversion recovery (FLAIR) and T2-weighted MR images. After thiamine administration, the high signal intensity in the former region disappeared immediately, while that in the latter regions persisted. The low level of N-acetylaspartate (NAA)/creatine (Cr) in the thalamus before thiamine administration improved to some degree on the (1)[H]-MRS images taken after thiamine administration. In the cerebellum, a lactate peak was observed before thiamine administration, and the NAA/Cr level did not improve after thiamine administration, suggesting that irreversible necrosis occurred. It is suggested that serial MRI/(1)H-MRS observation may be helpful in determining the neuronal viability of Wernicke's encephalopathy and the prognostic implications of sequelae such as Korsakoff's syndrome and cerebellar ataxia.

Measurement of the rate of nu(e) + d --> p + p + e(-) interactions produced by (8)B solar neutrinos at the Sudbury Neutrino Observatory

Solar neutrinos from (8)B decay have been detected at the Sudbury Neutrino Observatory via the charged current (CC) reaction on deuterium and the elastic scattering (ES) of electrons. The flux of nu(e)'s is measured by the CC reaction rate to be straight phi(CC)(nu(e)) = 1.75 +/- 0.07(stat)(+0.12)(-0.11)(syst) +/- 0.05(theor) x 10(6) cm(-2) s(-1). Comparison of straight phi(CC)(nu(e)) to the Super-Kamiokande Collaboration's precision value of the flux inferred from the ES reaction yields a 3.3 sigma difference, assuming the systematic uncertainties are normally distributed, providing evidence of an active non- nu(e) component in the solar flux. The total flux of active 8B neutrinos is determined to be 5.44+/-0.99 x 10(6) cm(-2) s(-1).

Neuronal damage in the interval form of CO poisoning determined by serial diffusion weighted magnetic resonance imaging plus 1H-magnetic resonance spectroscopy

In a patient with the interval form of carbon monoxide (CO) poisoning diffusion weighted MRI and proton magnetic resonance spectroscopy (1H-MRS) were serially performed immediately after the appearance of delayed sequelae (the 23rd day after exposure). During the period in which few clear findings were evident on MRI T2 weighted images, a high signal area in the cerebral white matter and relative decrease in the apparent diffusion coefficient (ADCav) were already apparent on diffusion weighted images, with these findings thought to sensitively reflect the tissue injury associated with the onset of sequelae. The decrease in relative ADCav persisted until the 38th day after exposure. Subsequently, ADCav gradually increased, and in the cerebral white matter showed higher values in the 118th day after exposure than immediately after the onset of sequelae. During this period, on 1H-MRS choline containing compounds showed persistently high values throughout the course, with N-acetylaspartate depletion and the appearance of a lactate peak later in the course. These findings, with regional specificity in the cerebral white matter, reflect the developmental process of the white matter lesions in the interval form of CO poisoning in which demyelination progresses leading to neuronal necrosis. Serial diffusion weighted imaging plus 1H-MRS measurements are useful in determining the tissue damage and long term outcome of delayed sequelae associated with the interval form of CO poisoning.

Intestinal permeability testing using lactulose and rhamnose: a comparison between clinically normal cats and dogs and between dogs of different breeds

In the experiment reported here, the lactulose/rhamnose urinary excretion test was used to compare intestinal permeability between four breeds of healthy adult dogs and a group of healthy adult cats. A significant difference in permeability was found between dogs and cats (P <0.001) and between different breeds of dogs (P <0.005). The range of urinary lactulose/rhamnose ratios in the dogs in this study (0.07-0.61) was wider than previously reported (0.03-0.12). The mean value for dogs was 0.19. The range in cats was 0.41-1.25 and the mean 0.52. The results of this study suggest that breed or some other factor such as environment, diet or sexual status as well as species should be taken into account when assessing intestinal permeability using the lactulose/rhamnose urinary excretion test.

Dual-subtype FIV vaccine protects cats against in vivo swarms of both homologous and heterologous subtype FIV isolates

OBJECTIVE

To evaluate the immunogenicity and efficacy of an inactivated dual-subtype feline immunodeficiency virus (FIV) vaccine.

DESIGN

Specific-pathogen-free cats were immunized with dual-subtype (subtype A FIV(Pet) and subtype D FIV(Shi)) vaccine and challenged with either in vivo- or in vitro-derived FIV inocula.

METHODS

Dual-subtype vaccinated, single-subtype vaccinated, and placebo-immunized cats were challenged within vivo-derived heterologous subtype B FIV(Bang) [10--100 50% cat infectious doses (CID(50))], in vivo-derived homologous FIV(Shi)(50 CID(50)), and in vitro- and in vivo-derived homologous FIV(Pet)(20--50 CID(50)). Dual-subtype vaccine immunogenicity and efficacy were evaluated and compared to single-subtype strain vaccines. FIV infection was determined using virus isolation and proviral PCR of peripheral blood mononuclear cells and lymphoid tissues.

RESULTS

Four out of five dual-subtype vaccinated cats were protected against low-dose FIV(Bang) (10 CID(50)) and subsequently against in vivo-derived FIV(Pet) (50 CID(50)) challenge, whereas all placebo-immunized cats became infected. Furthermore, dual-subtype vaccine protected two out of five cats against high-dose FIV(Bang) challenge (100 CID(50)) which infected seven out of eight single-subtype vaccinated cats. All dual-subtype vaccinated cats were protected against in vivo-derived FIV(Pet), but only one out of five single-subtype vaccinated cats were protected against in vivo-derived FIV(Pet). Dual-subtype vaccination induced broad-spectrum virus-neutralizing antibodies and FIV-specific interferon-gamma responses along with elevated FIV-specific perforin mRNA levels, suggesting an increase in cytotoxic cell activities.

CONCLUSION

Dual-subtype vaccinated cats developed broad-spectrum humoral and cellular immunity which protected cats against in vivo-derived inocula of homologous and heterologous FIV subtypes. Thus, multi-subtype antigen vaccines may be an effective strategy against AIDS viruses.

Phospholipid abnormalities in postmortem schizophrenic brains detected by 31P nuclear magnetic resonance spectroscopy: a preliminary study

It has been hypothesized that schizophrenia arises from cell membrane abnormalities due to changes in phospholipid (PL) composition and metabolism. We have used high resolution, in vitro 31P nuclear magnetic resonance (NMR) to characterize the PLs in left frontal cortex (gray matter) of postmortem brain from four schizophrenics and five controls. High resolution 31P NMR spectra were obtained in an organic-solvent system to resolve PL classes (headgroups) and in a sodium-cholate, aqueous dispersion system to resolve phosphatidylcholine (PC) molecular species. Multivariate analysis which included the major PC molecular species and phosphatidylinositol (PI) showed a significant difference between schizophrenics and controls. Analysis of specific interactions showed that the PI was significantly higher in the schizophrenic group than in the control group. There were no differences between the two groups for other individual PL classes, or for individual PL subclasses determined by the linkage type at the sn-1 position on glycerol. There was a trend for total PL content to be higher in schizophrenics than in controls. There was no evidence for elevated lysophosphatidylcholine or lysophosphatidylethanolamine in schizophrenia. The intensity of the PC peak representing molecular species with one saturated and one unsaturated (one or two double bonds) acyl chain was higher for the schizophrenic group than for the control group. Although these results are not in complete agreement with previous studies, they support the idea that PL abnormalities occur in the brain in schizophrenia and that fatty acid metabolism may be abnormal.

[Toxicity study of cefmatilen hydrochloride hydrate (S-1090) (5)--Six-month repeated oral dose toxicity study and supplement study in rats]

Cefmatilen hydrochloride hydrate (S-1090) was orally administered to rats at dose levels of 100, 300 and 1000 mg potency/kg once daily for 6 months. All the S-1090 treated groups showed soft feces, reddish-brown feces (due to chelated products of S-1090 or its decomposition products with Fe3+ in the diet), abdominal distention, increased food and water consumption, lower urine pH, and a decrease of white blood cells counts (except for males of the 100 mg potency/kg group). One male in the 300 mg potency/kg group showed mucous feces and marked decrease in body weight, and diet in the middle stage of the administration period. In necropsy of the survivors of all treated groups, marked cecal enlargement was noted. No remarkable changes were observed in the other examination items. From the early stage of the withdrawal period, animals in the 1000 mg potency/kg group showed again soft or mucous feces and a marked decrease in body weight. Of these animals, one male died and another male was sacrificed in a moribund state at about 2 weeks of the withdrawal period. Enterocolitis was observed in these cases. Almost all animals recovered within 3 weeks of withdrawal. A supplemental study of the 6-month toxicity study was conducted to examine the mechanisms of enterocolitis and the changes observable in the 100 or 300 mg potency/kg groups after drug withdrawal. As a reference, cefdinir (CFDN), an oral cephem antibiotic the same as S-1090, was added in the 1000 mg potency/kg group. No deaths occurred in any groups. Decreased intestinal flora were noted in all the groups treated with S-1090 or CFDN at the end of the dosing period. At 2 weeks of the withdrawal period, C. difficile and its D-1 toxin in the cecal contents were highly detected in the S-1090 300 and 1000 mg potency/kg groups and CFDN group. Inflammatory changes in the cecum and colon were observed in these groups. At 4 weeks of the withdrawal period, intestinal flora in the S-1090 groups almost returned to the condition before dosing, but those in the CFDN group were retained highly. Cecal D-1 toxin in the CFDN group was positive and higher than in the S-1090 groups. It was thus considered that the critical condition with enterocolitis resulted from C. difficile, which proliferated more rapidly than the other bacteria and D-1 toxin produced by this bacteria in the withdrawal period. Above changes were commonly observed in the CFDN group. The NOAEL of S-1090 was assessed to be 100 mg potency/kg/day which induced no enteritis.

Monochloramine inhibits etoposide-induced apoptosis with an increase in DNA aberration

Monochloramine (NH(2)Cl) is a physiological oxidant produced by activated neutrophils, and it affects apoptosis signaling. We studied the effects of NH(2)Cl on the cell death induced by etoposide, a widely used anticancer agent that is directed to DNA topoisomerase II. Jurkat T cells, a human acute T cell leukemia cell line, were pretreated with 70 microM of NH(2)Cl for 10 min. After 24 h, 5-30 microM of etoposide was added to the NH(2)Cl pretreated and control cells, and their apoptosis, caspase activity, cell morphology, and cellular DNA contents were measured. NH(2)Cl pretreatment significantly inhibited apoptosis and caspase activation induced by etoposide or camptothecin, a DNA topoisomerase I poison, but not by staurosporine or Fas stimulation. The apoptosis inhibition actually resulted in the proliferation of the survived cells and, notably, the survived cells showed more aberrant morphology, such as variation in nuclear size, nuclear fragments, and multinucleated cells. DNA content analysis of the survived cells showed an increase in aneuploid nuclei. Cell cycle analysis after 24 h of NH(2)Cl treatment showed a significant decrease in S phase cells with a concurrent increase in G(0)/G(1) phase cells, which suggested that NH(2)Cl induced G(1) arrest. Using synchronized Jurkat cells, etoposide and camptothecin were found to be particularly cytotoxic to S phase cells, whereas staurosporine and Fas stimulation were not. Thus NH(2)Cl-induced G(1) arrest was a likely cause of the observed resistance to etoposide. These observations suggested that inflammation-derived oxidants may make the tumor cells more resistant to etoposide and increase the risk of tumor progression and the development of secondary tumors by increasing the survival of DNA damage-bearing cells.

Effect of increased dietary protein and decreased dietary carbohydrate on performance and body composition in racing Greyhounds

OBJECTIVE

To determine effects of increased dietary protein and decreased dietary carbohydrate on hematologic variables, body composition, and racing performance in Greyhounds.

ANIMALS

8 adult Greyhounds.

PROCEDURE

Dogs were fed a high-protein (HP; 37% metabolizable-energy [ME] protein, 33% ME fat, 30% ME carbohydrate) or moderate-protein (MP; 24% ME protein, 33% ME fat, 43% ME carbohydrate) extruded diet for 11 weeks. Dogs subsequently were fed the other diet for 11 weeks (crossover design). Dogs raced a distance of 500 m twice weekly. Rectal temperature, hematologic variables before and after racing, plasma volume, total body water, body weight, average weekly food intake, and race times were measured at the end of each diet period.

RESULTS

When dogs were fed the MP diet, compared with the HP diet, values (mean +/- SD) differed significantly for race time (32.43 +/- 0.48 vs 32.61 +/- 0.50 seconds), body weight (32.8 +/- 2.5 vs 32.2 +/- 2.9 kg), Hct before (56 +/- 4 vs 54 +/- 6%) and after (67 +/- 3 vs 64 +/- 8%) racing, and glucose (131 +/- 16 vs 151 +/- 27 mg/dl) and triglyceride (128 +/- 17 vs 104 +/- 28 mg/dl) concentrations after racing.

CONCLUSIONS AND CLINICAL RELEVANCE

Greyhounds were 0.18 seconds slower (equivalent to 0.08 m/s or 2.6 m) over a distance of 500 m when fed a diet with increased protein and decreased carbohydrate. Improved performance attributed to feeding meat to racing Greyhounds apparently is not attributable to increased dietary protein and decreased dietary carbohydrate.

An fMRI study of the functional neuroanatomy of picture encoding in younger and older adults

Age-related changes in the neural mechanisms of picture encoding were investigated using functional magnetic resonance imaging (fMRI). Seven younger and seven older adults were studied while they were encoding pairs of concrete-related, concrete-unrelated, and abstract pictures. Functional (T2*-weighted) and anatomical (T1-weighted) images of the brain were obtained using a 1.5 T MRI scanner. The results in the younger adults showed that the left dorsal prefrontal cortex (PFC) was activated during associative learning of the concrete-unrelated or abstract pictures. The results also suggest that both ventral and dorsal visual pathways are involved in the encoding of abstract pictures, and that the right superior parietal lobule likely mediates spatial information of the abstract pictures. The older adults showed significant activation in the left dorsal PFC under concrete-unrelated and abstract conditions. However, the older adults failed to activate either the left ventral and right dorsal PFC under the concrete-unrelated condition, or the parietal areas under abstract condition. A direct comparison between the two age groups demonstrates that the older adults had a reduced activation in the bilateral parieto-temporo-occipital areas under abstract condition, and in the right temporo-occipital area extending to the fusiform gyrus under the concrete-unrelated condition. Finally, age difference was found in correlation between memory performance and amplitude of signal change in the parahippocampal gyrus and fusiform gyrus under the concrete-unrelated and abstract conditions. These changes in neural response likely underlie the age-related memory decline in relation to pictorial information.