[Non-traumatic dissecting aneurysms on the intracranial internal carotid artery: report of three cases]

Subarachnoid hemorrhage (SAH) due to non-traumatic dissecting aneurysms is uncommon. Most of such cases are reported to occur in the posterior circulation. We encountered three cases of non-traumatic dissecting aneurysms on the intracranial internal carotid artery. Two cases developing SAH from the dissecting aneurysms were surgically treated by such means as proximal ligation and trapping. Two cases, which were treated surgically during the acute phase, showed poor surgical outcome, because a large cerebral infarction took place during the course of vasospasm. Trapping of the ICA or the contralateral ICA with the dissecting aneurysm failed to keep enough blood supply despite hypervolemic hypertensive therapy. Operative results seemed to depend on the collateral circulation during vasospasm, so appropriate bypass surgery was recommended in cases of dissecting aneurysm on the ICA manifesting SAH. Furthermore, the mechanism of initiation of a dissecting aneurysm on the intracranial carotid artery was discussed from the biorheological aspect.

[Respiratory muscle weakness after prolonged use of hydrocortisone and pancuronium bromide]

A 30-year-old man was admitted because of status asthmaticus. He required 7 days of artificial ventilation and was treated with hydrocortisone 1.2 g.day-1 and bronchodilaters. Pancuronium bromide 0.08 mg.kg-1.hr-1 was given for 64 hours for the ease of artificial ventilation. On day 3, severely elevated airway pressure resulted in left pneumothorax and isoflurane 1% was given for the following 2 days. Respiratory muscle weakness was evident 24 hours after discontinuation of pancuronium infusion on day 5 while full 4 twitches of TOF on the adductor pollicis muscle were seen at the time. The respiratory muscle weakness continued for another 3 days and he was extubated on day 8. Serum creatine kinase concentration rose to 2178 U.l-1 on day 6 and returned to normal on day 11. Hematurea, hyperpyrexia and metabolic acidosis were never seen during the course. Acute corticosteroid myopathy was suspected to be the cause of the prolonged respiratory muscle weakness.

Automated filtration-based high-throughput plasmid preparation system

Current methods of plasmid preparation do not allow for large capacity automated processing. We have developed an automated high-throughput system that prepares plasmid DNA for large-scale sequencing. This system is based on our previously reported filtration method. In this method, cell harvesting, alkaline lysis, and plasmid purification occur in a single 96-well microtiter plate from which sequence-ready DNA samples are collected. The plates are designed to allow all reagents to be injected from above the wells and the spent reagents to be aspirated from below. This design has enabled us to build a linear process plasmid preparation system consisting of an automated filter plate stacker and a 21-stage automated plasmid preparator. The 96-well plates used are outfitted with glass-filters that trap Escherichia coli before the plates are stacked in the automated stacker. The plates move from the stacker to each of the 21 stages of the preparator. At specific stages, various reagents or chemicals are injected into the wells from above. Finally, the plates are collected in the second stacker. The optimal throughput of the preparator is 40,000 samples in 17.5 hr. Here, we describe a pilot experiment preparing 15,360 templates in 160 specially designed 96-well glass-filter plates. The prepared plasmids were subjected to restriction digestion, DNA sequencing, and transcriptional sequencing.

Current treatment strategies and factors influencing outcome in patients with bacterial brain abscess

We clearly determined the key to managing patients with brain abscess by retrospectively evaluating the factors affecting poor outcome in these patients. This study included 113 patients with brain abscess diagnosed in the CT era. Basic characteristics and therapeutic parameters were estimated as independent predictors of poor outcome by using univariate and multivariate logistic regression analysis. Patients with poor outcomes more frequently had deeply-located abscesses (p < 0.02), IVROBA (intraventricular rupture of brain abscess (p < 0.001) and were in a severely deteriorated neurological state (p < 0.001) than those with good outcomes. Multiple logistic regression analysis predicted that IVROBA (ORs, 24.5; 95% CI, 3.04 to 197.9) and severely deteriorated cases (ORs, 13.7; 95% CI, 2.34 to 80.8) resulting from IVROBA increased the relative risk of poor outcome. Patients with IVROBA more frequently had also deeply-located abscesses (p < 0.005), positively immunocompromised states (p < 0.05) and were in a severely deteriorated condition (p < 0.003) than those without IVROBA. Patients with metastatic abscess had also IVROBA (p < 0.006). Multiple logistic regression analysis anticipated that deeply-located abscess (ORs, 3.90; 95% CI, 1.38 to 11.04), and metastatic abscess (ORs, 12.26; 95% CI, 1.35 to 111.2) increased the relative risk of IVROBA. Patients in an obtunded state and with marked neurological deficit had IVROBA more often than patients in an alert state and/or mild neurological deficit (ORs, 3.23; 95% CI, 1.17 to 8.86, p < 0.03) before treatment. Our findings suggest that IVROBA strongly influences poor outcome in patients with brain abscess. The key to decreasing poor outcomes may be the prevention and management of IVROBA, by evaluating intracranial pressure pathophysiology. IVROBA should be aggressively treated by aspiration methods for the abscess coupled with appropriate intravenous and intrathecial administration of antibiotics.

Identification of stable RNA hairpins causing band compression in transcriptional sequencing and their elimination by use of inosine triphosphate

To identify stable RNA secondary structure causing band compression, 30 lambda DNA clones and four cDNA clones (about 10 kb in total length) were sequenced using Transcriptional Sequencing, which is based on the phage RNA polymerase chain termination reaction with fluorescent 3' deoxynucleoside triphosphate, using the canonical set of rNTPs for the substrate. Electrophoresis was performed on acrylamide gel containing 7 M urea at 50 degrees C using ABI 377 DNA sequencer. A total of 159 band compressions were identified, and most compression sites seem to be due to hairpin structures. We also found that the presence of rITP in place of rGTP in the sequencing reaction can entirely eliminate all band compressions. The use of rITP gave a better peak uniformity and resolution in the sequencing gel in the case of lambda DNA than with c7rGTP, leading to improved accuracy in the sequence determination. Substitution of the base analog rITP for rGTP should be useful for accurate sequencing determination.

[Spontaneous resolution of idiopathic spinal subdural hematoma: case report]

A 32-year-old female presented with about a week's history of dull pain in the head and neck pain. On the day of admission, she experienced a sudden onset of severe pain, extending from the occipital to the lower back region and hypesthesia and paresthesia of the right C8-Th3 dermatome. On admission, she was alert but there was a band of hypesthesia and paresthesia at the level of C8-Th3. Cervical X-ray, computed tomography scan (CT) and magnetic resonance images (MRI) of the head revealed no definite abnormalities. The peripheral blood picture was normal, and the bleeding and clotting times were in the normal range. The cerebrospinal fluid (CSF) was bloody and the CSF pressure was 220 mm H2O. An emergent 4-vessel intracranial angiography disclosed no abnormal findings. MRI and myelography revealed an intradural extramedullary lesion extending from the Th2 to the Th5 levels, ventral to the spinal cord. A T1-weighted MR image showed iso-low intensity and a T2-weighted MR image showed low intensity at these lesions. Spinal angiography revealed no abnormal vessels. In one month, spinal compression cleared gradually without surgery and her clinical symptoms disappeared about 40 days after admission. Spontaneous spinal subdural hematoma is uncommon and only 28 cases have been reported. 15 cases have been treated with surgical procedure, but spinal compression cleared spontaneously in this case. This spontaneous recovery is such a rare event that only 3 such cases have been reported in the literature. However, with the prevailing MRI, this disease will be detected more frequently in the future.

Expression of the apoptosis-related genes, caspase-1, caspase-3, DNA fragmentation factor, and apoptotic protease activating factor-1, in human granulosa cells

OBJECTIVE

To investigate protein and messenger RNA expression products for a subset of apoptosis-related genes in human granulosa cells.

DESIGN

In vitro experiment.

SETTING

Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.

PATIENT(S)

Women undergoing oocyte retrieval for IVF after ovulation induction with gonadotropins.

INTERVENTION(S)

Granulosa cells were isolated from follicular aspirates after oocyte removal.

MAIN OUTCOME MEASURE(S)

Reverse transcription polymerase chain reaction and Western blotting for apoptosis-related gene products.

RESULT(S)

The expression of caspase-1, caspase-3, DNA fragmentation factor, and apoptotic protease activating factor-1, which are intermediate molecules in phylogenetically conserved apoptotic pathways, was demonstrated in granulosa cells from patients undergoing IVF. Moreover, proforms, but not activated enzymes, for both caspase-1 and caspase-3 were observed.

CONCLUSION(S)

Granulosa cells from patients undergoing IVF have intrinsic apoptotic machinery that could be activated for tissue remodeling.

Specific detection of sialyl Lewis X determinant carried on the mucin GlcNAcbeta1-->6GalNAcalpha core structure as a tumor-associated antigen

Sialyl Lewis X serves as a ligand for selectins and is proposed to be implicated in hematogenous metastasis of cancers. When a cultured human breast cancer cell line, MCF-7, which does not express sialyl Lewis X, was transfected with human fucosyltransferase VI cDNA, a strong expression of sialyl Lewis X was induced on transfectant cells. The transfectant cells were found to be also reactive to the antibody NCC-ST-439, which was initially raised against human gastric cancer cells and later was shown to recognize a tumor-associated carbohydrate antigen in breast, gastric, and colon cancers. This suggested that the antigen recognized by NCC-ST-439 is closely related to sialyl Lewis X. Subsequent studies indicated that NCC-ST-439 specifically reacts to NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6GalNAcalpha1 -->R, the sialyl Lewis X on the mucin GlcNAcbeta1-->6 GalNAcalpha structure. The antibody was not reactive to the conventional sialyl Lewis X determinants on straight and/or branched polylactosamine structures including NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->3Galbeta1-->4 Glcbeta1-->R and NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6Galbeta1-->4 Glcbeta1-->R. This was in clear contrast to most of the known anti-sialyl Lewis X antibodies, which do not discriminate internal structures carrying the sialyl Lewis X determinant. On the other hand, the newly generated monoclonal antibody GSC154-27 had a specificity completely the reverse of the specificity of NCC-ST-439 in that it was strongly reactive to the conventional sialyl Lewis X determinants in straight and branched polylactosamine structures, while far less reactive to the sialyl Lewis X determinant on the mucin GlcNAcbeta1-->6GalNAcalpha core structure. A set of these two antibodies would be useful in discriminating the molecular species of sialyl Lewis X expressed by malignant cells and in studying their functional significance.

Recognition sites of 3'-OH group by T7 RNA polymerase and its application to transcriptional sequencing

When analyzing the elongation mechanisms in T7 RNA polymerase (T7 RNAP)by using site-directed mutagenesis and a protein expression system, we identified the recognition sites of the rNTP 3'-OH group in T7 RNAP. On the basis of three-dimensional crystal structure analysis, we selected and analyzed six candidate sites interacting with the 3'-OH group of rNTP in T7 RNAP. We found that the Phe-644 and Phe-667 sites are responsible for the high selectivity of T7 RNAP for rNTPs. Also, we constructed the protein mutations of these residues, F644Y and F667Y, which display a >200-fold higher affinity than the wild type for 3'-dNTPs. These findings indicate that the phenylalanine residues of 644 and 667 specifically interact with the 3'-OH group. Thus, these mutants, F644Y and F667Y, with incorporation of 3'-dNTP terminators, which is similar to native rNTPs, can offer low backgrounds and equal intensities of the sequencing ladders in our method, called "transcriptional sequencing. "

[Usefulness of positron emission tomography to STA-MCA anastomosis for the case with cerebral infarction]

The ischemic area surrounding the cerebral infarction in the eloquent area was salvaged by STA-MCA bypass surgery. Both the misery perfusion area evaluated by positron emission tomography (PET) using the [15O] gas inhalation steady-state method and clinical symptoms improved within a year after surgery. To confirm the ischemic area and select the suitable recipient artery was important for successful bypass surgery, because only an artery covering the ischemic area is expected to have low resistance. In this case a large ischemic area with disturbed, vasodilatation by Diamox was detected on the SPECT. However, PET clearly exposed the localized misery perfusion area in the overestimated ischemic area by SPECT. We describe our experience and discuss the technique and efficacy of PET for STA-MCA anastomosis surgery.

Installation of new damped cavities at the Photon Factory storage ring

New damped cavities have been installed in the Photon Factory (PF) storage ring and successfully operated in the last scheduled user run of 1996. The new damped cavity is a simple single-cell cavity with somewhat large beam-duct holes. The part of the beam duct that is attached to the cavity is made of SiC, which works as a microwave absorber and damps the higher-order modes excited in the cavity. Because of its simple structure, the operation of the cavity is very stable and also a high power input of more than 150 kW is possible. No coupled-bunch instabilities due to the new cavity were observed during operation.

Reconstruction for the brilliance-upgrading project of the Photon Factory storage ring

Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence when the improvements are completed on 1 October 1997.

Identification of a major carbohydrate capping group of the L-selectin ligand on high endothelial venules in human lymph nodes as 6-sulfo sialyl Lewis X

We investigated the molecular species of sulfated sialyl Lewis X determinants, the putative L-selectin ligand, expressed on high endothelial venules (HEV) in human lymph nodes. Comparison of the reactivity pattern of HEV with the reactivity of the pure 6-sulfo, 6'-sulfo, or 6,6'-bissulfo sialyl Lewis X determinant with hitherto known anti-sialyl Lewis X antibodies strongly suggested 6-sulfo sialyl Lewis X to be the best candidate for the major sulfated sialyl Lewis X determinant on HEV, followed by 6,6'-bissulfo sialyl Lewis X, whereas 6'-sulfo sialyl Lewis X was unlikely. We newly generated monoclonal antibodies (mAbs) G152 and G72 directed against 6-sulfo sialyl Lewis X, which intensely labeled HEV in immunohistochemical examination and inhibited binding of recombinant L-selectin-IgG to HEV, suggesting that the determinant serves as a ligand for L-selectin. To test the concomitant expression of 6, 6'-bissulfo sialyl Lewis X, specific mAbs (G2706, G27011, G27037, and G27039) were generated, but all antibodies failed to react to HEV. Next, we established mAbs (AG97 and AG273) directed against 6-sulfo Lewis X, the asialo form of 6-sulfo sialyl Lewis X. The antibodies were not reactive to untreated HEV, but strongly reacted to sialidase-treated HEV. This indicated the predominance of the sialylated form of 6-sulfo sialyl Lewis X and minimal expression of its asialo form, corroborating that it was synthesized by fucosyltransferase VII, the isoenzyme that preferentially produces the sialylated form of the determinant.

Characterization of gene expression in mouse blastocyst using single-pass sequencing of 3995 clones

To study the gene expression profile in the mouse blastocyst and to identify embryonic stage-specific genes, we randomly selected cDNAs derived from mouse blastocysts and sequenced a total of 3995 clones from one or both ends. Excluding the uninformative clones, 3395 clones were grouped as 937 different kinds of genes. Among these, 465 and 406 species showed similarity to known genes and expressed sequence tags (ESTs), respectively, whereas 66 species showed no significant similarity to any genes in known databases. Analysis of these cDNAs revealed that this library contained a variety of functional genes as well as genes that have not been detected in the human EST database; it should provide us with a useful resource for molecular analysis of developmental mechanisms. Although the human EST project is considered to represent roughly half of all genes, our findings indicate that many early stage developmental genes remain to be identified.

Transcriptional sequencing: A method for DNA sequencing using RNA polymerase

We have developed a sequencing method based on the RNA polymerase chain termination reaction with rhodamine dye attached to 3'-deoxynucleoside triphosphate (3'-dNTP). This method enables us to conduct a rapid isothermal sequencing reaction in <30 min, to reduce the amount of template required, and to do PCR direct sequencing without the elimination of primers and 2'-dNTP, which disturbs the Sanger sequencing reaction. An accurate and longer read length was made possible by newly designed four-color dye-3'-dNTPs and mutated RNA polymerase with an improved incorporation rate of 3'-dNTP. This method should be useful for large-scale sequencing in genome projects and clinical diagnosis.

Identification of a transcript predicting an alternative form of sulfated glycoprotein-2 (clusterin) in rat tissues

As a clue to understand the role of androgen in rat seminal vesicle, we have isolated several cDNA clones of androgen-responsive mRNAs. During further characterizations of these cDNAs were in progress, a distinct cDNA clone designated p116 was isolated. The sequence study suggested the expression of a transcript predicting an alternative form of Sulfated Glycoprotein-2 (SGP-2)/clusterin. RT-PCR demonstrated the androgen-dependent expression of p116 transcript in the seminal vesicles. The transcript was also detectable in the ventral prostate, the liver and the thymus. Since SGP-2 has been suggested as a classical molecular marker of apoptosis, p116 transcript newly identified in the present study might provide a useful probe to further understand the roles of SGP-2 and its related proteins during the course of apoptotic process not only in male accessory sex organs, but also in many types of cells undergoing apoptosis.

[Efficacy of nicardipine prolonged-release pellet on cerebral vasospasm in dogs]

A drug delivery system using copoly (lactic/glycolic acid) was developed for the intrathecal administration of nicardipine. This system was tested to determine its efficacy in preventing cerebral vasospasm in dogs. A rod-shaped implant (1-mm diameter, 10-mm long and which contained approximately 10% of nicardipine) was prepared by a heat compression method. In in vitro studies, 8% of the actual nicardipine loaded was released during day 1, 17% within day 2, 62% within day 4, and 96% within day 10. In in vivo studies, 12 dogs were assigned to two groups: the placebo group and the group treated with nicardipine. Angiography before the experiment was performed followed by right craniectomy and induction of subarachnoid hemorrhage by the placement of a clot in the Sylvian fissure. Eight pellets, either containing 8 mg of nicardipine or without nicardipine were placed in the cistern. On day 7, the angiography was repeated and cerebrospinal fluid was removed from the cisterna magna. The animals were then sacrificed, and the brain and blood clot were taken out. Cerebral vessels were measured three times with a calibrated optical micrometer, and the mean value was obtained. Average reduction of vessel diameters on the clot side in the placebo and nicardipine groups were -37% and -10% on the internal carotid (IC), -48% and -3% on the middle cerebral (MC), and -28% and -1% on the anterior cerebral artery (AC), respectively. There were significant differences in vessel diameters of IC (p < 0.05), MC (p < 0.005), and AC (p < 0.05) between these groups. No vasospasm was found in the left side. The nicardipine concentration in the clot was determined by high performance liquid chromatography. The mean concentration of nicardipine in the clot was 1.5 x 10(-4)M, at which concentration sufficient relaxation is evoked in vitro. The pellets did not last beyond day 7. Regarding the histological findings, there was a marked difference in vessel diameters between the placebo and the nicardipine treated groups. The arteries were surrounded with red blood cells and inflammatory cells. There were no specific changes related to the pellets and no sign of meningoencephalitis. A prolonged-release preparation of nicardipine that can be implanted intracranially at the time of surgery prevented vasospasm significantly in dogs. These results suggest that this new drug delivery system might be put into effect favorably in patients suffering from vasospasm due to subarachnoid hemorrhage.

Prophylactic effect of papaverine prolonged-release pellets on cerebral vasospasm in dogs

OBJECTIVE

A drug delivery system using copoly(lactic/glycolic acid) was developed for the intracranial administration of papaverine. A rod-shaped implant prepared by a heat compression method was tested to determine its efficacy in preventing cerebral vasospasm in dogs.

METHODS

Sixteen dogs were randomly assigned to one of two groups, i.e., placebo or papaverine. Control angiography was performed, followed by right craniectomy and the induction of subarachnoid hemorrhage by the placement of a clot in the Sylvian fissure. Two pellets, containing either 25 mg of papaverine or no papaverine, were placed in the cistern. In in vitro studies, 56% of the actual papaverine loading was released in the first 4 days and 78% within 8 days. On Day 7, angiography was repeated and the animals were killed. A similar experiment using low-dose pellets containing 5 mg of papaverine, half of which was released within 7 days, was performed with 16 mongrel dogs.

RESULTS

There were significant differences between the papaverine- and placebo-treated groups in the reductions of vessel diameters of the internal carotid, middle cerebral, and anterior cerebral arteries on the clot side. The mean concentration of papaverine in the clot was 4.5 x 10(-4) mol/L. The low-dose pellet failed to prevent cerebral vasospasm, although the mean concentration of papaverine in the clot was 2.3 x 10(-5) mol/L.

CONCLUSION

A prolonged-release preparation of papaverine that could be implanted intracranially at the time of surgery prevented vasospasm significantly while maintaining an appropriate concentration of papaverine in the cistern.

Mechanism of hypocholesterolemic action of S-8921 in rats: S-8921 inhibits ileal bile acid absorption

The mechanism of the hypocholesterolemic action of S-8921, methyl 1-(3,4-dimethoxyphenyl)-3-(3-ethylvaleryl)- 4-hydroxy-6,7,8-trimethoxy-2-naphthoate, was examined in rats. In diet-induced hypercholesterolemic rats, 2 weeks oral administration of S-8921 dose- and time-dependently decreased plasma cholesterol level in the daily dose range of 0.1 to 10 mg/kg. Results with the dual-isotope plasma ratio method indicated that S-8921 inhibits cholesterol absorption from the intestine and enhances its elimination from the body. The in situ loop method showed that S-8921 does not inhibit the absorption of cholesterol from rat jejunum, clearly inhibits active absorption of taurocholic acid (TCA) and glycocholic acid (GCA) from rat ileum and does not inhibit passive absorption of cholic acid (CA) from the rat jejunum. In rat ileal brush-border membrane vesicles, S-8921 inhibited the sodium-dependent uptake of TCA in a concentration-dependent manner with IC50 of 2.1 microM, not the Na(+)-dependent D-glucose and L-alanine uptake. These results suggest that S-8921 is a potent, selective inhibitor of the Na(+)-dependent bile acid transport system in the ileal mucosal cell brush-border membrane, and this inhibition is the mechanism by which this drug decreases intestinal bile acid reabsorption to result in a significant decrease of plasma cholesterol.

A novel control system for polymerase chain reaction using a RIKEN GS384 thermalcycler

We have developed a novel high-throughput thermalcycler, the RIKEN GS384, which has a maximum of 1536 wells and whose temperature can be controlled accurately and simultaneously for a very small volume of a reaction mixture. In practice, the reaction is carried out using four 384-well (3.5 mm in diameter) plate formats which can be automatically moved using a robotic arm. To achieve accurate temperature control with high thermo-conductivity, we adopted Teflon-coated aluminum well plates closely sandwiched between silicon sheet-covered lids on top and a graphite sheet below. The lids were kept at a higher temperature (2 to 5 degrees C) than the reaction wells. The temperature of the 1536 sample wells was controlled accurately without temperature variability among the wells or evaporation, even for samples of very small volume (minimum 2 microliters). We also developed a new type of plate format which is similar to the 384-well place in terms of plate size, shape, and material, but which differs in the number (1536) and size (1.6 mm in diameter) of the wells. Since the amplification reactions could be done precisely as well, a total of 6144 reactions can potentially be carried out simultaneously using the GS384 thermalcycler. This is very promising for DNA microfabrication technology. This thermalcycler offers the advantage of high-throughput DNA analysis which should be useful for DNA diagnoses or for the human genome project.

Current treatment of brain abscess in patients with congenital cyanotic heart disease

OBJECTIVE

The goal of this study was to define clearly the role of management in patients with cyanotic heart disease and brain abscesses by evaluating retrospectively the factors influencing poor outcome in these patients.

METHODS

This study included 62 patients with cyanotic heart disease and brain abscesses diagnosed in the computed tomography era. Basic characteristic parameters (number, size, location, computed tomographic classification and organism type of abscess, convulsion, type of cyanotic heart disease, age distribution, immunocompromised status, pretreatment neurological state, and intraventricular rupture of brain abscess [IVROBA]) and therapeutic parameters (type of antibiotics and duration of administration, steroid medication and therapeutic modalities, aspiration with or without cerebrospinal fluid drainage, total extirpation after aspiration, or primary extirpation and medical treatment) were evaluated as independent predictors of poor outcome (totally disabled state or death) by using univariate and multivariate logistic regression analysis. We also statistically estimated the possible causes of IVROBA and the multiplicity of brain abscess.

RESULTS

Although there were no statistically significant correlations between patients with good and poor outcomes in regard to other basic characteristic and therapeutic parameters, patients with poor outcomes were older (P < 0.02), more frequently had IVROBA (P < 0.005), and had a higher frequency of neurological deterioration (P < 0.01) than those with good outcomes. Multiple logistic regression analysis predicted that poor outcome increased the relative risk of IVROBA by a factor of 18.9 (odds rate, 18.9; 95% confidence interval, 1.7-211.6; P < 0.02). More patients with multiple abscesses had positive immunocompromised states than those with single abscesses (P < 0.01). Deep-located abscesses also more frequently had IVROBA (P < 0.005) and abscesses located in the parieto-occipital region ruptured into the occipital horn of the lateral ventricle in a short period (P < 0.02).

CONCLUSIONS

Our findings suggest that IVROBA strongly influences poor outcome in patients with cyanotic heart disease. The key to decreasing poor outcomes may be the prevention and management of IVROBA. To reduce operative and anesthetic risk in these patients, abscesses should be managed by less invasive aspiration methods guided by computed tomography. Abscesses larger than 2 cm in diameter, in deep-located or parieto-occipital regions, should be aspirated immediately and repeatedly, mainly using computed tomography-guided methods to decrease intracranial pressure and avoid IVROBA. IVROBA should be aggressively treated by aspiration methods for the abscess coupled with the appropriate intravenous and intrathecal administration of antibiotics while evaluating intracranial pressure pathophysiology.

Induction of a receptor-mediated genomic DNA fragmentation in rat thymus following administration of glucocorticoids with different biopotencies: an approach by a cell-free system

To further understand a receptor-mediated apoptosis in rat thymus, we undertook experiments to examine the relationship between the induction of genomic DNA fragmentation and the depletion and the replenishment of cytosolic glucocorticoid receptor in rat thymus. Following administration of dexamethasone and prednisolone which had been known as synthetic glucocorticoids with different biological activities, we observed the fragmentation of thymus DNA in a dose-dependent manner. The time course and the extent of DNA fragmentation induced by these glucocorticoids were closely related to the degree of receptor depletion and the length of the depletion period. Relative biopotencies of dexamethasone and prednisolone estimated by their abilities to induce the DNA fragmentation were approximately 50:1. Administration of dexamethasone in combination with 2-deoxy-D-glucose, a potent inhibitor of the glycolytic pathway, significantly decreased the ability of dexamethasone to induce the DNA fragmentation, suggesting that a receptor-mediated DNA fragmentation by glucocorticoids is an ATP-dependent process. As an attempt to elucidate the molecular mechanism of DNA fragmentation in vivo, we reconstituted a cell-free system of thymus nuclei and cytosol fraction. Using the thymus cytosol fraction from dexamethasone-treated rats, we demonstrated for the first time an ATP-dependent fragmentation of nuclear DNA into nucleosomal units in vitro. Toward further understanding of the biochemical process of glucocorticoid-induced apoptosis in the thymocyte, the cell-free system reconstituted in the present study might provide a useful model system.