Pharaonis phoborhodopsin binds to its cognate truncated transducer even in the presence of a detergent with a 1:1 stoichiometry

Pharaonis phoborhodopsin (ppR) (also pharaonis sensory rhodopsin II) is a receptor of the negative phototaxis of Natronobacterium pharaonis. ppR forms a complex with its pharaonis halobacterial transducer (pHtrII), and this complex transmits the light signal to the sensory system in the cytoplasm. The expressed C-terminal-His tagged ppR and C-terminal-His tagged truncated pHtrII (t-Htr) in Escherichia coli (His means the 6x histidine tag) form a complex even in the presence of 0.1% of n-dodecyl-beta-D-maltoside, and the M-decay of the complex became about twice slower than that of ppR alone. The photocycling rates under varying concentration ratios of ppR to t-Htr in the presence of detergent were measured. The data were analyzed on the following assumptions: (1) the M-decay of both ppR alone and the complex followed a single exponential decay with different time constants; and (2) the M-decay under varying concentration ratios of ppR to t-Htr, therefore, followed a biexponential decay function which combined the decay of the free ppR and that of the complex as photoreactive species. From these analyses we estimated the dissociation constant (15.2 +/- 1.8 microM) and the number of binding sites (1.2 +/- 0.08).

Clinical characteristics of B-cell lymphoma-associated hemophagocytic syndrome (B-LAHS): comparison of CD5+ with CD5- B-LAHS

OBJECTIVE

B-cell lymphoma-associated hemophagocytic syndrome (B-LAHS) has been increasingly reported in Asia and is regarded as a variant of intravascular lymphomatosis (IVL). Recently CD5 was reported to be expressed in some cases of diffuse large cell lymphoma and IVL. We therefore examined the expression of CD5 on lymphoma cells in B-LAHS and compared the clinical and laboratory data between CD5+ and CD5- B-LAHS.

METHODS

The expression of CD5 on lymphoma cells was examined using flow cytometry and immunohistochemical analysis of paraffin sections. The clinical records were reviewed to characterize clinical features.

PATIENTS

Twelve patients with B-LAHS; ten men and two women, age ranging from 41 to 82 years (median, 63.5 years) were included in this study.

RESULTS

B-LAHS is characterized by fever and hepatosplenomegaly without lymphadenopathy at the initial presentation. Histological examination showed hemophagocytosis and infiltration of lymphoma cells in the bone marrow, and in some cases intravascular proliferation of lymphoid cells characteristic of IVL. All patients showed increased levels of lactate dehydrogenase, C-reactive protein, ferritin and soluble interleukin-2 receptor. In eight of the twelve patients, lymphoma cells were positive for CD5. But no differences were observed in the clinical or laboratory findings between CD5+ B-LAHS and CD5- B-LAHS.

CONCLUSION

No clinical differences were observed between CD5+ B-LAHS and CD5- B-LAHS. Further studies are required to elucidate the differences in pathogenesis between these two subgroups of B-LAHS.

Structural changes of pharaonis phoborhodopsin upon photoisomerization of the retinal chromophore: infrared spectral comparison with bacteriorhodopsin

Archaeal rhodopsins possess a retinal molecule as their chromophores, and their light energy and light signal conversions are triggered by all-trans to 13-cis isomerization of the retinal chromophore. Relaxation through structural changes of the protein then leads to functional processes, proton pump in bacteriorhodopsin and transducer activation in sensory rhodopsins. In the present paper, low-temperature Fourier transform infrared spectroscopy is applied to phoborhodopsin from Natronobacterium pharaonis (ppR), a photoreceptor for the negative phototaxis of the bacteria, and infrared spectral changes before and after photoisomerization are compared with those of bacteriorhodopsin (BR) at 77 K. Spectral comparison of the C--C stretching vibrations of the retinal chromophore shows that chromophore conformation of the polyene chain is similar between ppR and BR. This fact implies that the unique chromophore-protein interaction in ppR, such as the blue-shifted absorption spectrum with vibrational fine structure, originates from both ends, the beta-ionone ring and the Schiff base regions. In fact, less planer ring structure and stronger hydrogen bond of the Schiff base were suggested for ppR. Similar frequency changes upon photoisomerization are observed for the C==N stretch of the retinal Schiff base and the stretch of the neighboring threonine side chain (Thr79 in ppR and Thr89 in BR), suggesting that photoisomerization in ppR is driven by the motion of the Schiff base like BR. Nevertheless, the structure of the K state after photoisomerization is different between ppR and BR. In BR, chromophore distortion is localized in the Schiff base region, as shown in its hydrogen out-of-plane vibrations. In contrast, more extended structural changes take place in ppR in view of chromophore distortion and protein structural changes. Such structure of the K intermediate of ppR is probably correlated with its high thermal stability. In fact, almost identical infrared spectra are obtained between 77 and 170 K in ppR. Unique chromophore-protein interaction and photoisomerization processes in ppR are discussed on the basis of the present infrared spectral comparison with BR.

Scavenger cells with gram-positive bacterial lipoteichoic acid infiltrate around the damaged interlobular bile ducts of primary biliary cirrhosis

BACKGROUND/AIMS

Gram-positive bacterial DNA is frequently detectable in gallbladder bile of primary biliary cirrhosis (PBC) patients. To advance these findings, lipoteichoic acid (LTA) of gram-positive bacteria with high antigenicity was examined in liver specimens and bile from PBC patients and controls.

METHODS

LTA was examined by Western blotting in the gallbladder bile from 15 PBC, 11 cholecystolithiasis and six normal subjects, and by immunohistochemistry in liver specimens from 16 PBC, six primary sclerosing cholangitis (PSC), eight chronic viral hepatitis C (CVH-C) and five normal subjects.

RESULTS

In the gallbladder bile, there was no significant difference in the positive rate of LTA between PBC and controls. LTA-containing mononuclear cells were frequently detected in the portal tracts, particularly around the bile ducts and in hepatic sinusoids in PBC, while they were infrequent or occasional in control livers. These LTA-containing cells were sinusoidal endothelial cells and Kupffer cells, and portal monocytes, which frequently expressed scavenger receptor class B type 1.

CONCLUSIONS

LTA derived from bacterial fragments may reach the bile, not only in the diseased state but also under normal conditions. Such LTA may be involved in the development and progression of portal tract lesions, particularly bile duct lesions, in PBC.

Cortical activity associated with vocalization and reading proper

To determine whether motor and premotor areas are involved in silent reading, we report a positron emission tomography study on reading aloud and covert reading. The anterior insula, primary sensorimotor cortex and supplementary motor area were activated separately in reading aloud compared with covert reading, but they were not activated in covert reading compared with fixation control, nor in a conjunction involving reading aloud and covert reading, suggesting the role of articulation or vocalization.

7Li 2D CSI of human brain on a clinical scanner

Lithium salts have been widely used in the treatment of mood disorders, but the mechanism of action is still not clear. In this work, a methodology for two-dimensional Lithium-7 imaging on clinical systems is presented. The data were acquired using a phosphorus volume head coil that was re-tuned for the Lithium-7 frequency. A spectroscopic sequence was used to acquire the free induction decay (FID) after volume excitation using a hard pulse. The results obtained on the head of patients undergoing lithium treatment (n = 7, 0.6 mEq/l average serum level) demonstrate that images of adequate signal to noise ratio (100:1) can be obtained in acceptable imaging times (55 min) using the proposed methodology. The distribution of 7Li appears uniform in the brains of the patients studied.

Age-related reduction of extrastriatal dopamine D2 receptor measured by PET

Although the aging effect of dopamine D2 receptor in the striatum is well-documented, the effect of age on the extrastriatal dopamine D2 receptor has not been fully examined. Since the density of extrastriatal dopamine D2 receptor is very low, suitable ligands are limited. In this study, we used [11C]FLB 457 to quantify the extrastriatal dopamine D2 receptor in the living human brain. Twenty-seven healthy male subjects aged from 21 to 82 years participated in the positron emission tomography study. Extrastriatal [11C]FLB 457 binding was quantified with a reference tissue model using cerebellum as a reference region. Binding potentials corresponding to Bmax/Kd were used to evaluate age-related change. We found age-related decreases of D2 receptor binding in all measured extrastriatal regions. The decrease of D2 receptor binding was 13.8% per decade in frontal cortex, 12.0% in temporal cortex, 13.4% in parietal cortex, 12.4% in occipital cortex, 12.2% in hippocampus, and 4.8% in thalamus. These findings suggest that the amounts of D2 receptor declines in all brain regions as part of the normal aging process.

Simultaneous coronary arterial bypass surgery using mini-sternotomy and off-pump methods and abdominal aneurysm repair

A technique of combined minimally invasive coronary artery surgery and abdominal aneurysm repair is described. A mini-sternotomy and off-pump coronary artery bypasses to the left descending branch and right coronary arteries are conducted before abdominal aneurysm repair in a simultaneous operation.

Dopamine D2 receptors in the insular cortex and the personality trait of novelty seeking

Human personality has been considered to have a neurochemical background. We examined the relation between extrastriatal dopamine D2 receptor binding in living human brain and the personality trait of novelty seeking that has been proposed to be related to dopaminergic function in the brain. We measured extrastriatal dopamine D2 receptors of 24 healthy young male subjects using [(11)C]FLB 457 positron emission tomography. The personality trait of each subject was assessed by the Temperament and Character Inventory (TCI). Correlation of dopamine D2 receptor binding with novelty seeking was calculated using region-of-interest analysis and statistical parametric mapping based on the binding potential images generated using a reference tissue model. A significant negative correlation was observed between binding potential values and the novelty seeking scores on TCI in the right insular cortex. No significant correlation was observed in any other region. Our result indicates that there is a significant association between dopamine D2 receptor binding and the human novelty seeking trait in the right insular cortex.

Pulsatile cardiopulmonary bypass failed to prevent neuropsychological dysfunction

To prevent neurological complications during cardiopulmonary bypass, cerebrovascular screenings by magnetic resonance angiography and computed tomographic scan of the brain were performed preoperatively in patients who had ischemic heart disease and all patients aged 60 years or older. From 1996 to 1999, 173 adult patients (mean age 65.1+/-7.7 y) were evaluated. Forty-one patients were considered to be at high risk from the screening tests and pulsatile cardiopulmonary bypass was applied. The remaining 132 patients were placed in the control group. Postoperative cerebral infarction caused by embolism was encountered in three patients (3/173, 1.7%), two in the high-risk group (2/41, 4.8%) and one in the control group (1/132, 0.8%), but the difference between these incidences was not statistically significant. Cerebral infarctions caused by brain hypoperfusion did not occur in this series. A neuropsychological test (Hasegawa's dementia scale, HDS) was done pre- and postoperatively. No one was diagnosed with dementia preoperatively, whereas 7 patients were diagnosed with dementia postoperatively. Among these 7 patients, 6 patients were in the high-risk group (17.1%, 6/35) and one patient was in the control group (0.9%, 1/113). Under these circumstances, using cerebrovascular screening and pulsatile cardiopulmonary bypass, cerebral infarction due to hypoperfusion did not occur, but cerebral infarction due to embolism was encountered, and neuropsychological dysfunction was not prevented.

Increased expression of WAF1 in intrahepatic bile ducts in primary biliary cirrhosis relates to apoptosis

BACKGROUND/AIMS

In primary biliary cirrhosis (PBC), the intrahepatic small bile ducts are selectively damaged by immune attacks, followed by progressive loss mainly due to apoptosis. Compared to the intercellular signaling such as the CD95/CD95 ligand interaction, little is known about alterations in intracellular cell cycle regulatory proteins and genotoxic damage in this apoptotic process. WAF1 is a potent and reversible inhibitor of cell cycle progression at both the G1 and G2 checkpoint and upregulated WAF1 induces irreversible G1 arrest and apoptosis. Transcriptional activation of the WAF1 gene is induced by the upregulated p53 in response to DNA damage. In this study, the cell cycle regulatory process of apoptosis in PBC was examined with respect to expression of WAF1.

METHODS

Immunostaining for WAF1 and p53 was performed using 11 liver sections of PBC and 26 control livers. In addition, Ki67, apoptosis (TUNEL-positive), and human telomerase RNA (hTR) were also detected.

RESULTS

WAF1 was expressed in the nuclei of several epithelial cells in most damaged bile ducts in PBC but infrequently or rarely in controls. Some of these cells were also positive for p53, while the remainder were not. Ki67 immunostaining and TUNEL disclosed that the bile ducts in PBC showed increased cell division as well as enhanced apoptosis. Immunostaining of Ki67 and TUNEL staining showed that WAF1-positive cells were not proliferating, while some WAF1-positive cells were undergoing apoptosis. Moreover, the bile ducts lacked hTR expression, implying progressive shortening of telomeres during increased cell divisions.

CONCLUSIONS

It seems possible that in PBC, expression of WAF1 on biliary epithelial cells relates to the apoptosis. p53 may be involved in this upregulation. This may be due to physiological upregulation of WAF1 and p53 in response to genotoxic damage such as oxidative stress associated with cholangitis, suggesting other processes than CD95/CD95 ligand interaction in biliary epithelial apoptosis in PBC.

Relation among dopamine D(2) receptor binding, obesity and personality in normal human subjects

Personality is a behavioral pattern, which differs among individuals. Kretschmer (Kretschmer, E., Physique and Character: an Investigation of the Nature of Constitution and the Theory of Temperament, New York, 1921) categorized personality variants according to the concept of fundamental body types. Recently, several lines of evidence suggest that the central dopamine system may underlie the regulation of weight and the personality trait. In this study, we examined the dopamine D2 receptor (D2R) binding using positron emission tomography with [11C]FLB 457 [(s)-N-[(1-ethyl-2-pyrrolidinyl) methyl]-5-bromo-2,3-dimethyloxybenzamide] together with body mass index (BMI) and personality trait on the temperament and character inventory (TCI) in 16 normal subjects. Our data demonstrate that there was a significant relation among D2R binding in the amygdala, BMI and personality trait of harm avoidance. It can be assumed that variation of dopaminergic activity in the amygdala underlies the personality variants related to the concept of fundamental body type.

Molecular identification of bacterial 16S ribosomal RNA gene in liver tissue of primary biliary cirrhosis: is Propionibacterium acnes involved in granuloma formation?

The etiopathogenesis of primary biliary cirrhosis (PBC) remains speculative. Epithelioid granulomas are often found in the vicinity of damaged interlobular bile ducts in PBC, raising the possibility of a reaction to microbial materials. In this study, we tried to detect and identify bacterial DNA within granulomatous lesions in PBC. Using liver sections from 9 patients with PBC and 13 control livers, granuloma in portal tracts, portal tracts without granuloma, and adjacent hepatic parenchyma were selectively microdissected from sections, and then DNA was extracted from them. First, part of the bacterial 16S ribosomal RNA (rRNA) gene was amplified from DNA samples extracted from 5 PBC and 6 control livers, and their amplicons were sequenced for the identification of bacterial species. Several indigenous bacteria were identified. Among them, Propionibacterium acnes (P. acnes) was detected as a major clone in 20% to 50% of sequenced clones from granuloma of PBC, but the detection rate of P. acnes was 0% to 20% in those cloned from adjacent hepatic parenchyma of PBC. Then, a P. acnes-specific PCR was performed using all microdissected samples. Distinct PCR products were identified in epithelioid granuloma in all 9 PBC cases. The result that P. acnes DNA is present as a major clone in granulomas of PBC, suggest that P. acnes is involved in the pathogenesis of granuloma in PBC.

Error analysis for quantification of [(11)C]FLB 457 binding to extrastriatal D(2) dopamine receptors in the human brain

To estimate receptor binding of ligand by positron emission tomography (PET) without an arterial input function, several quantitative approaches based on the use of a reference region have been proposed. We compared three approaches for quantifying extrastriatal D(2) dopamine receptors using [(11)C]FLB 457. The PET measurements were performed on seven healthy men. Binding potential (BP) of [(11)C]FLB 457 was calculated by the reference tissue model method, transient equilibrium method, and late time method. The reference tissue model describes the time-activity curve in a brain region in terms of that in the reference region, assuming that the levels of nondisplaceable radioligand binding in both regions are the same. The transient equilibrium theoretically occurs when the derivative for specific binding is zero. With the late time method, BP is calculated by integrating a late part of the time-activity curve. BP values obtained by all methods were in good agreement with those obtained by the kinetic approach, and the highest coefficient of correlation was observed in the reference tissue model method. In the simulation study, the error of BP calculated by the reference tissue model method was smallest. Moreover, the effect of the difference in the influx rate constant K(1) between the brain and the reference regions on BP was nearly avoided as theoretically predicted. We concluded that the reference tissue model method is most suitable for calculating BP of extrastriatal D(2) dopamine receptors with [(11)C]FLB 457.

Ten year progressive ventricular enlargement in schizophrenia: an MRI morphometrical study

Recent studies of the brain using magnetic resonance imaging (MRI) have suggested progressive structural changes in schizophrenics. However, those studies were conducted over periods of less than 5 years and thus lacked sufficient capacity to determine the course and nature of this process. In this study, MRI scans were obtained in 15 schizophrenics and 12 controls at baseline and after 4- and 10-year follow ups. Volumes of the lateral ventricles were measured. Patients were assessed by the Brief Psychiatric Rating Scale (BPRS) at the same two time points: at baseline and at 10-year follow up. After 10 years, a significant lateral ventricular enlargement was found in patients (mean percentage change: +22.9%) but not in controls (5.1%). Although our results are not in disagreement with the neurodevelopmental hypothesis, they do provide strong evidence that in schizophrenia progressive brain reduction occurs even in its chronic stage.

Dose relationship of limbic-cortical D2-dopamine receptor occupancy with risperidone

RATIONALE

It has been suggested that the antipsychotic effect of antipsychotics is mediated by the antagonism of the dopamine D2 receptor in the limbic-cortical regions. Risperidone has an atypical property, but its effect on limbic-cortical regions has not been evaluated.

OBJECTIVES

In this study, we examined the relationship among doses of risperidone and limbic-cortical dopamine D2 receptor occupancy using positron emission tomography.

METHODS

Seven patients with schizophrenia were scanned during the steady state with risperidone. Their occupancies in limbic-cortical regions were determined using positron emission tomography with [11C]FLB 457.

RESULTS

The average occupancy ranged from 38% to 80% on doses of 1-6 mg/day. The saturation curve plotted against the drug level fit the data well.

CONCLUSIONS

Our results demonstrate that the D2 receptor occupancy with risperidone in the limbic-cortical regions seems to be similar to that of previous reports regarding the striatum, and it would be comparable to that of typical antipsychotics.

Cortical activation in reading assessed by region of interest-based analysis and statistical parametric mapping

Reanalysis of our positron emission tomography study on the reading of Japanese Kanji (morphograms) and Kana (phonograms) with Statistical Parametric Mapping (SPM) Version 96 (Cogn. Brain Res. 9 (2000) 111) were described in comparison with our previous region of interest (ROI)-based analysis. Some areas were activated in one analysis but not in the other, which was due to the methodological differences. Furthermore, we conducted cognitive subtraction analysis between Kanji and Kana and between Kana words and nonwords and confirmed that Kana words activated the lateral occipital gyri more extensively than Kanji words.

Photo-induced proton transport of pharaonis phoborhodopsin (sensory rhodopsin II) is ceased by association with the transducer

Phoborhodopsin (pR; also sensory rhodopsin II, sRII) is a retinoid protein in Halobacterium salinarum and works as a receptor of negative phototaxis. Pharaonis phoborhodopsin (ppR; also pharaonis sensory rhodopsin II, psRII) is a corresponding protein of Natronobacterium pharaonis. In bacterial membrane, ppR forms a complex with its transducer pHtrII, and this complex transmits the light signal to the sensory system in the cytoplasm. We expressed pHtrII-free ppR or ppR-pHtrII complex in H. salinarum Pho81/wr(-) cells. Flash-photolysis experiments showed no essential changes between pHtrII-free ppR and the complex. Using SnO2 electrode, which works as a sensitive pH electrode, and envelope membrane vesicles, we showed the photo-induced outward proton transport. This membranous proton transport was also shown using membrane vesicles from Escherichia coli in which ppR was functionally expressed. On the other hand, the proton transport was ceased when ppR formed a complex with pHtrII. Using membrane sheet, it was shown that the complex undergoes first proton uptake and then release during the photocycle, the same as pHtrII-free ppR, although the net proton transport ceases. Taking into consideration that the complex of sRII (pR) and its transducer undergoes extracellular proton circulation (J. Sasaki and J. L., Biophys. J. 77:2145-2152), we inferred that association with pHtrII closes a cytoplasmic channel of ppR, which lead to the extracellular proton circulation.

Pretreatment with FK506 improves survival rate and gas exchange in canine model of acute lung injury

The novel effects of FK506 on shock induced by lipopolysaccharide and phorbol myristate acetate (LPS/PMA) were studied using beagles. Five groups were studied: endotoxin shock control group (both 0.5 mg/kg of LPS and 30 microg/kg of PMA, n = 6); methylprednisolone-treated endotoxin shock group (n = 5); FK506-treated endotoxin shock groups in which intravenous infusions of FK506 at 2.5 microg/kg/h (low dose, n = 5), 8 microg/kg/h (medium dose, n = 5), and 25 microg/kg/h (high dose, n = 5) were administered. In the control group, the survival rate was 33%. Also, arterial hypoxemia, systemic hypotension, and marked increases in pulmonary vascular resistance (PVR) and wet-to-dry weight ratio (W/D) were observed. FK506 treatment at both medium and high doses significantly attenuated these LPS/PMA-induced physiological changes, and the survival rates were 80 and 100%, respectively. On the other hand, in the methylprednisolone group, no obvious effects were observed. The present study suggests that FK506 could have prophylactic potential against acute lung injury in endotoxin shock.

Reduced volume of the cerebellar vermis in neuroleptic-naive schizophrenia

BACKGROUND

Neuroimaging studies have suggested the possible role of the cerebellum in the pathophysiology of schizophrenia. However, no study has investigated the detailed structures of the cerebellum in patients without a history of neuroleptic medication. The objective of this study is to examine the volume of detailed structures of the cerebellum in neuroleptic-naive schizophrenic patients and to examine the relationship between cerebellar morphology and clinical symptoms.

METHODS

Magnetic resonance imaging scans were acquired from 20 male neuroleptic-naive schizophrenic patients and 20 healthy control subjects. We measured the volumes of the cerebrum, cerebellar hemisphere, cerebellar gray and white matter, and vermis. Symptoms were assessed with the Brief Psychiatric Rating Scale. Total Brief Psychiatric Rating Scale scores and subscale scores were used for analysis.

RESULTS

The volume of the vermis was significantly reduced in the schizophrenic group relative to the control group, whereas no significant differences were found in the volumes of other cerebellar structures and the cerebrum. Reduction in the vermal volume correlated with the total Brief Psychiatric Rating Scale Depression subscore and Paranoia subscore.

CONCLUSIONS

This study indicates that the volume of the vermis is reduced in patients with schizophrenia, and reduction in vermal volume is suggested to be related to the pathophysiology of the disease.

Strategy for reduction of stroke incidence in coronary bypass patients with cerebral lesions. Early results and mid-term morbidity using pulsatile perfusion

OBJECTIVES

Cerebral complication is an important factor affecting the outcome after coronary artery bypass surgery under cardiopulmonary bypass. One of the causes for cerebral complication is preoperative cerebrovascular stenotic lesion. Here, we have studied the effect of pulsatile perfusion on the rate of cerebral complication due to a cerebrovascular lesion in patients undergoing coronary arterial bypass graft under cardiopulmonary bypass.

METHODS

261 consecutive elective patients underwent operation using cardiopulmonary bypass for management of the atherosclerotic ascending aorta. Group 1 consisted of 62 patients with a cerebrovascular stenotic lesion (> or = 75%) identified on a magnetic resonance angiogram or multiple cerebral infarction diagnosed using a computer tomogram. Group 2 consisted of 199 patients diagnosed with no significant cerebral lesion. In Group 1, the systolic blood pressure during cardiopulmonary bypass was maintained at a level of 80 mmHg by means of pulsatile flow. In Group 2, non-pulsatile perfusion was used as usual.

RESULTS

The overall hospital mortality was 1.5%, and no mortality was caused by a cerebral event. Only one patient in Group 1 suffered from temporary hemiparalysis. A cerebral complication occurred in only 1.6% in Group 1, and 0.4% overall. The actuarial freedom from cerebrovascular accident after 54 months was 84.4% in Group 1, and 96.2% in Group 2 (p = 0.0011).

CONCLUSIONS

Management of the atherosclerotic ascending aorta and the use of pulsatile perfusion were helpful in preventing cerebral injury during CABG.

Serotonin 5-HT2 receptors in schizophrenic patients studied by positron emission tomography

Using positron emission tomography (PET) and [11C]N-methylspiperone (NMSP), we examined 5-HT2 receptors in the cortex of schizophrenic patients in whom we previously observed decreased prefrontal D1 receptor binding. The subjects were 10 neuroleptic-naive schizophrenic patients, 7 schizophrenic patients who were drug-free but had previously been treated with neuroleptics, and 12 normal controls. A non-significant trend towards decreased prefrontal [11C]NMSP binding was observed in the neuroleptic-treated patients, suggesting a possible effect of previous neuroleptic treatment on the alteration in cortical 5-HT2 function. However, the neuroleptic-naive patients showed no noticeable difference in cortical [11C]NMSP binding compared to controls. Our results do not rule out the role of 5-HT2 function as a crucial site of therapeutic activity of schizophrenia, but they do suggest that cortical 5-HT2 receptors might not be primarily involved in the pathophysiology of schizophrenia.

Expression of T-cell-associated antigens in B-cell non-Hodgkin's lymphoma

We performed the immunophenotyping of 101 patients with B-cell non-Hodgkin's lymphoma (B-NHL) using two-colour flow cytometry (FCM) and found that lymphoma cells coexpressed at least one kind of T-cell-associated antigen (T-Ag; CD2, CD5, CD7) in 25 patients (24. 8%). Among these three T-Ags, CD5 was the most frequently expressed, in 21 patients (20.8%), followed by CD7, expressed in five patients (5.0%), and CD2, which was expressed in two patients (2.0%). Two kinds of T-Ag were simultaneusly expressed in three patients (CD2/CD5, CD2/CD7, and CD5/CD7, each expressed in one patient). Concerning the expression pattern of T-Ag, there were no significant differences between lymph nodes and extranodal organs in the three patients with T-Ag-positive B-NHL (T-Ag(+) B-NHL) who were analysed. When comparing the clinical features between T-Ag(+) B-NHL and T-Ag-negative B-NHL (T-Ag(-) B-NHL), extranodal involvement and higher International Prognostic Index (H and H.I.) were significantly frequent in the former subgroup (P = 0.0119 and P = 0. 0302 respectively).

The effect of carbon dioxide tension on cerebral circulation during hypothermic selective cerebral perfusion

BACKGROUND

Some reports have observed the response of cerebral blood flow to PaCO2 during hypothermic cardiopulmonary bypass. We studied the effect of PaCO2 on the cerebral circulation during hypothermic selective cerebral perfusion.

METHODS

Between June 1992 and January 1998, 35 patients underwent aortic arch grafting using hypothermic selective cerebral perfusion (20 degrees C). In the earlier four patient (Group 1), carbon dioxide gas was not added. In the latter 31 patient (Group 2), carbon dioxide gas was added to the cerebral perfusion. The hemodynamics and rates of change in cerebral oxygen saturation were evaluated.

RESULTS

In Group 1, the index of cerebral arterial resistance was 9.2+/-2.2 at the start of selective cerebral perfusion and increased to 15.7+/-0.1 at the re-warming stage (p<0.05), and there was a significant decrease in cerebral oxygen saturation at the re-warming stage (p<0.001). In Group 2, the index of cerebral arterial resistance was 4.7+/-1.7 at the start of selective cerebral perfusion and 4.3+/-1.5 at the re-warming stage, a non-significant change. The change in cerebral oxygen saturation was also nonsignificant between the start of selective cerebral perfusion and the re-warming stage. Among the neurological outcomes, there was only one small cerebral infarction in Group 2; however, no delayed conscious recovery was observed.

CONCLUSIONS

The addition of CO2 to cerebral perfusion was a factor in inhibiting the increase in the cerebral vascular resistance at the re-warming stage.