Comparison of hemodynamic changes resulting from toxic shock syndrome toxin-1-producing Staphylococcus aureus sepsis and endotoxin-producing gram-negative rod sepsis in patients with severe burns

Five patients with burns and toxic shock syndrome toxin-1 (TSST-1)-producing Staphylococcus aureus sepsis (TSS group) were treated in a 5-year period at Kyorin University Hospital's Traumatology and Critical Care Center Burn Unit. Hemodynamic and metabolic differences in these patients were compared retrospectively with those in another five patients who were matched by burn index and age and in whom endotoxin-producing gram-negative rod sepsis developed (End group). Both groups showed hypermetabolic and hyperdynamic changes at the point sepsis developed. There were no significant differences between the two groups in any parameter. At the point septic shock developed, the TSS group showed significantly lower mean (+/- SD) arterial pressure (TSS vs End group, 64 +/- 5 vs 74 +/- 5 mm Hg; p < 0.05), significantly lower systemic vascular resistance index (TSS vs End group, 579 +/- 62 vs 729 +/- 75 dynes.sec.cm-5/m2; p < 0.05), and higher oxygen consumption (TSS vs End group, 190 +/- 7 vs 163 +/- 11 L/min/m2; p < 0.05) compared with the End group. This is the first clinical report that asserts that TSST-1-producing gram-positive sepsis may result in more hypermetabolic and hyperdynamic differences than does endotoxin-producing gram-negative rod septic shock. These responses may indicate a stronger stimulation of cytokine and nitrous oxide synthetic activity by TSST-1 than by endotoxin.

Detection of hypervascular hepatocellular carcinoma by dynamic MRI and dynamic spiral CT

OBJECTIVE

Our goal was to evaluate the detectability of hypervascular hepatocellular carcinomas (HCCs) by multislice dynamic MRI and dynamic spiral CT.

MATERIALS AND METHODS

Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, the liver was subjected to T1- and T2-weighted SE-MRI, multislice dynamic MRI after intravenous bolus injection of Gd-DTPA, early phase imaging with spiral CT (dynamic spiral CT) after intravenous bolus injection of contrast medium (at a rate of 2 or 3 ml/s), and delayed phase CT in 64 patients with 208 HCC nodules. The detectability of HCCs by MRI and CT was evaluated retrospectively compared with CT after TACE as a gold standard.

RESULTS

The detectability of nodules < 1 cm in diameter was superior with dynamic MRI (67%) and dynamic spiral CT (50%) in comparison with SE-MRI (26%) and delayed phase CT (11%) (p < 0.01). The detectability of these tumors with dynamic MRI was significantly superior to that with dynamic spiral CT using an injection rate of 2 ml/s (p < 0.01), but not significantly different from that of dynamic spiral CT using a rate of 3 ml/s.

CONCLUSION

Dynamic MRI and dynamic spiral CT are comparable for detecting hypervascular intrahepatic metastases of HCC.

Blood pressure levels in school-age Japanese children: the Hisayama Study

Blood pressure (BP) measurements were obtained on a total of 6325 children (3294 boys and 3031 girls), aged 6-14 years, in Hisayama, Japan. All BPs were recorded in a sitting position by trained observers in a standardised manner. Standard mercury sphygmomanometers were used with commercially available cuffs, selected according to the arm circumference. Cuff size no. 3 (bladder width 9 cm, length 23 cm) was the one most commonly selected in 84% of elementary schoolers aged 6-11 years and in 35% of junior high schoolers aged 12-14 years. Mean systolic BPs (SBPs) increased from 89 mm Hg at age 6 years to 108 mm Hg at 14 years (a 21% increase) for boys and from 88 mm Hg to 102 mm Hg (a 16% increase) for girls. Diastolic BP (DBPs, Korotkoff phase IV, KIV) increased from ages 6 to 14 years to the same degree, from 58 mm Hg to 72 mm Hg (a 24% increase) for boys and from 58 mm Hg to 70 mm Hg (a 21% increase) for girls. The increase in DBP (Korotkoff phase V, KV) was greater, from 48 mm Hg to 63 mm Hg (a 30% increase) for boys and from 48 mm Hg to 61 mm Hg (a 28% increase) for girls. The increase in mean SBP for adolescent boys was greater compared with that of girls; however, separation of age-specific values by sex was not observed for mean DBP (KIV) and DBP (KV). The cross-sectional relation between age and mean SBP levels was not linear.

Tumor necrosis factor production by human T-cells stimulated with bacterial superantigens

Tumor necrosis factor (TNF) production from T-cells stimulated with superantigenic exotoxins, staphylococcal enterotoxin B and streptococcal pyrogenic exotoxin A was investigated in the presence of cells bearing distinct isotypes of HLA class II molecules. The main T-cell subset for TNF production was investigated in parallel. Similarly high levels of TNF production were induced upon stimulation with the toxins in the presence of DR+ or DQ+ cells, but only marginal levels of TNF production were induced in the presence of DP+ cells. Although both CD4+ T-cells and CD8+ T-cells produced TNF-alpha and TNF-beta in response to toxin stimulation in the presence of HLA class II+ cells, the former T-cell subset was the major source of producers of TNF-alpha and TNF-beta.

Protective effect of granulocyte colony-stimulating factor against T-cell-meditated lethal shock triggered by superantigens

The bacterial superantigens (SAg), toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin B (SEB), are powerful T-cell stimulators, triggering systemic release of lymphokines causing lethal shock in D-galactosamine (D-Gal)-sensitized mice. We show that pretreatment with recombinant human granulocyte colony-stimulating factor (rhG-CSF) protects mice against T-cell-mediated SAg-shock. In mice challenged with D-Gal/TSST-1, lethal shock was caused within 30 hours. In contrast, animals pretreated with two consecutive subcutaneous injections of 2 micrograms rhG-CSF with a 12-hour time interval showed only marginal signs of illness and no lethality after challenge with D-Gal/TSST-1. Mice treated with 5 micrograms rhG-CSF either 12 or 6 hours in advance also survived otherwise lethal doses of D-Gal/TSST-1. The protective effects of rhG-CSF pretreatment was also evident against lethal doses of D-Gal/SEB challenge and this protection was accompanied by suppression of systemic interleukin-2. However, rhG-CSF affected neither the proliferative responses of SAg-reactive T cells in vivo or in vitro nor their interleukin-2 production in vitro, implying that rhG-CSF may indirectly interfere with cytokine synthesis in T cells but not with T-cell-SAg binding itself. These results represent another beneficial effect of rhG-CSF as an anti-inflammatory agent against T-cell-mediated toxicity triggered by SAg.

The absence of evidence of staphylococcal toxin involvement in the pathogenesis of Kawasaki disease

To detect a causative superantigen and to clarify a possible role for staphylococci in Kawasaki disease (KD), culture supernatants of individual bacterial isolates from 11 acute-stage patients were studied. Toxic shock syndrome toxin-1 (TSST-1) and antibody to TSST-1 and enterotoxins A (SEA), B (SEB), and C (SEC) in acute (mean, day 7) and late convalescent (mean, month 15) sera from 26 patients (12 with coronary artery aneurysms) and 22 age-matched controls were measured. Only 1 of 60 supernatants was mitogenic for human lymphocytes; it was 1 of the 4 Staphylococcus aureus isolates. Mitogenicity was neutralized by sera obtained after administration of intravenous gamma globulin (mean, week 4) but not by late convalescent sera. TSST-1 was detectable in 2 of 26 acute sera and 1 of 22 control sera. No KD but 1 control serum had IgM to TSST-1. IgG seroconversion rates to TSST-1, SEA, SEB, and SEC were 10%, 15%, 21% and 16%, respectively. These data do not support the involvement of toxin-producing staphylococci in KD.

A simple and effective video keratometric system

We tested a personal computer-based video keratometric system used to analyze projected placido disk rings. The system consists of a Maloney surgical keratometer that projects the rings and a video camera attached to an operating microscope. Images of the rings were transmitted to a video image processing board and analyzed on a personal computer using an analysis program we developed. System precision was evaluated in 18 eyes. The values were compared with those obtained using a commercial photokeratometer (control). In all eyes, the principal meridian values differed from the controls by < 0.04 mm. In 15 eyes (83%), the measurements were within 0.03 mm of the controls. The corneal astigmatism values and cylindrical axes were within 0.12 diopters in 17 eyes (94%) and within 5 degrees in all cases, respectively. Our system, which can analyze placido disc rings projected from other systems, is sufficiently precise to measure the corneal radius of curvature and astigmatism.

Detectability of hypervascular hepatocellular carcinoma by arterial phase images of MR and spiral CT

The ability of arterial phase images of breath-hold MR imaging and spiral CT to detect hypervascular hepatocellular carcinomas (HCCs) was evaluated. Prior to transcatheter arterial chemoembolization (TACE) with iodized oil, MR images and spiral CT during i.v. bolus injection of contrast medium (IV-MR imaging and IV-spiral CT) and spiral CT during intraarterial injection of contrast media through catheter (IA-spiral CT) of the entire liver were obtained in 24 consecutive patients with 93 HCCs. In the detection of HCCs less than 1 cm in diameter, IA-spiral CT (87.3%) was superior to IV-MR imaging (63.5%) and IV-spiral CT (54.0%) (p < 0.001). There was no significant difference in detectability in any tumor size between IV-MR imaging and IV-spiral CT. IA-spiral CT was the best for detecting hypervascular HCCs, and there was no significant difference between IV-MR imaging and IV-spiral CT.

[An analysis of factors related to recurrence of superficial bladder cancer after transurethral resection]

A total of 205 patients with primary superficial bladder cancer (Ta, T1) followed more than 3 years were retrospectively analyzed for factors related to recurrence of tumors after transurethral resection. Patients age were 25 to 90 years old, average 61 years old, and there were 160 males and 45 females. Initial tumor grades were G0 in 4 patients, G1 in 48, G2 in 134 and G3 in 19. Seventy four patients had Ta tumor and 131 had T1. Initial treatments were transurethral resection (TUR) alone in 137 patients. TUR with intravesical chemotherapy in 64, with BCG therapy in 7 and others in 7. Factors examined included age, sex, chief complaint, shape, size, and number of tumors, tumor distribution (single area or multiple area), histological grade, stage and intravesical chemotherapy. Overall non-recurrent rate were 81.7% at 1 year, 60.7% at 3 year, 53. 8% at 5 year and 44.2% at 8 year. Five-year non-recurrent rate according tumor factors, showed significant difference regarding tumor size (< 1 cm or 1 cm <: P = 0.027), tumor number (single or multiple: P = 0.004), tumor distribution (single area or multiple area: p = 0.002), histological grade (< G1 or G2 < : p = 0.001) and stage (Ta or T1: p = 0001). However, there were no significant difference regarding factors of age, sex, chief complaint, tumor figure and presence or absence of intravesical chemotherapy. This results suggested that the tumor factors of size, number, tumor distribution, grade and stage were highly related to intravesical tumor recurrence of superficial bladder cancer.

Efficient and specific induction of esophageal tumors in rats by precursors of N-nitrososarcosine ethyl ester

Cancers and precancerous lesions of the esophagus were efficiently induced in rats by the simulation of a clinico-epidemiological setting; that is, the administration of precursors of nitrosamine. Six week old non-inbred male Wistar rats were given 2g/kg bodyweight of sarcosine ethyl ester hydrochloride (SEEH) and concurrently 0.3g/kg bodyweight of sodium nitrite (NaNO2), precursors of N-nitrososarcosine ethyl ester (NSEE), in 2% sucrose as drinking water. Group 1 received the precursors twice a week for 6 weeks followed by 8 weeks observation, and group 2, once every 3 days for 7 weeks followed by 26 weeks observation. At the end of treatment, no tumor had developed in the esophagus of rats in group 1, but the [3H]-thymidine labeling indices in both basal and superficial layer cells were higher than in the control group. On subsequent observation, papillomas appeared in group 1 (33.3%), and carcinomas in group 2 (33.3%), within 4 weeks. The tumors induced in group 1 were mostly papillomas and rarely carcinomas. When the observation was prolonged in group 2, 100% of the animals had cancer in week 20. The pathological changes of the lesions paralleled the sequential development of human squamous cell carcinoma of the esophagus. Our system has the advantages in that papillomas and cancers can be induced in rats in a short time and the agents used are less toxic than preformed nitrosamines administered previously by gastric intubation. It would serve as a useful experimental tool to study premalignant lesions and cancers of the esophagus.

Hepatocyte growth factor specifically expressed in microglia activated Ras in the neurons, similar to the action of neurotrophic factors

Hepatocyte growth factor (HGF) mRNA and its receptor (c-Met) mRNA were detected in the fetal and adult rat brain. Expression of c-Met mRNA was increased after birth. HGF mRNA was preferentially expressed in the microglia of the rat brain, while c-Met mRNA was expressed in neurons as well as astrocytes and microglia. Most of the neurons were c-Met positive, and HGF stimulated tyrosine phosphorylation of c-Met (140-kDa) in the neurons. HGF as well as bFGF also activated Ras in the neurons. These results suggest that HGF plays a biological role as one of the neurotrophic factors in the brain.

[Quinolone-resistant mutations in Neisseria gonorrhoeae]

For 10 strains of Neisseria gonorrhoeae exhibiting decreased susceptibility to new quinolones (MIC, > or = 0.1 microgram/ml) isolated and preserved from patients with gonococcal urethritis during the period from February 1991 through January 1992. We investigated the mechanisms for development of resistance to new quinolones. After selecting 3 PCG-sensitive and new quinolone-resistant strains from among these strains, we first carried out transformation experiments of N. gonorrhoeae using a plasmid carrying the E. coli gyrA gene. We then determined the base sequence on the N. gonorrhoeae gyrA gene by PCR method. Of the 3 strains in which transformation experiments were carried out, 2 strains yielded transformants, one of which was 8 times more sensitive to norfloxacin (NFLX) than the original strain, and it was assumed that this strain has a mutation in the gyrA gene. In our study of the base sequence on the N. gonorrhoeae gyrA gene using the PCR method, both strains had the mutation of Ser 83 (TCC)-->Phe (TTC), and in addition to this mutation of Ser-->Phe, one other strain had the mutation of Asp-87 (GAC)-->Gly (GGC). This type of mutation of quinolone-resistant N. gonorrhoeae on the gyrA gene has high homology with the mutations reported for Escherichia coli and other strains and there appears to be a close correlation between the increasing frequency of use of the new quinolones in this country and the spread of such resistant strains of N. gonorrhoeae.

Proliferative response and cytokine production of bovine peripheral blood mononuclear cells induced by the superantigens staphylococcal enterotoxins and toxic shock syndrome toxin-1

The potential of staphylococcal enterotoxin A (SEA), B (SEB), C(SEC) and toxic shock syndrome toxin-1 (TSST-1) to act as superantigens by inducing polyclonal T-cell mitogenesis and cytokine production was tested on bovine peripheral blood mononuclear cells (PBMC). These four toxins were capable of inducing strong proliferative response of PBMC from calves over a broad dosage range (1 pg/ml to 1 microgram/ml) in vitro. The toxin-activated blast cells consisted of both CD4+ T-cells and CD8+ T-cells, but the T-cell proliferation depended upon the presence of monocytes. Treatment of monocytes with monoclonal antibody to major histocompatibility complex class II antigens substantially inhibited the toxin-induced T-cell proliferative response, but paraformaldehyde-fixation did not abrogate the accessory function. SEA, SEB, SEC and TSST-1, all induced the in vitro release of interleukin-2, interferon gamma and tumor necrosis factor alpha in a dose dependent manner. The results indicate that SEA, SEB, SEC and TSST-1 are capable of acting as superantigens by stimulating bovine T-cells as shown in the human and murine systems. The possible implications of these toxins in the immunopathogenesis of bovine mastitis caused by the infection with Staphylococcus aureus are discussed.

Biphasic flow velocity pattern in the descending aorta in double aortic arch

We report a case of double aortic arch in which the biphasic flow velocity pattern in the descending aorta changed to a monophasic flow velocity pattern after corrective surgery. The hypoplasia of left aortic arch might prolong the acceleration time of the flow velocity in the left aortic arch.

Cardiac pacing in fetal lambs: intrauterine transvenous cardiac pacing for fetal complete heart block

To evaluate the feasibility of intrauterine transvenous cardiac pacing, the right ventricular output was measured during pacing in six fetal lambs. Under maternal anesthesia, the uterus was opened, and, under local anesthesia, the pacing lead (Medtronic Capsure SP4023) was inserted via the fetal left internal jugular vein. Right ventricular output was estimated using an Aloka SSD-730 ultrasound device, and tricuspid valve regurgitation was evaluated with an Aloka SSD-880 using the transuterine approach. The ultrasonic right ventricular cardiac output was measured under three different conditions: (1) with the tip of the pacing lead in the superior vena cava (control); (2) with the tip of the pacing lead in the right ventricle; and (3) with pacing at 200 beats/min. The right ventricular output decreased when the pacing lead was inserted into the right ventricle, as well as during pacing at 200 beats/min ([1] = 107 +/- 13.2 mL/kg per min; [2] = 73.8 +/- 17.5 mL/kg per min; and [3] = 78.3 +/- 23.6 mL/kg per min). Tricuspid regurgitation did not change under any of the conditions tested. Intrauterine transvenous cardiac pacing was successfully achieved. Insertion of the pacing lead into the right ventricle decreased the ventricular output without increasing tricuspid valve regurgitation.

Immunopathological activities of extracellular products of Streptococcus mitis, particularly a superantigenic fraction

Previously, we prepared extracellular products, fractions F-1 and F-2 of Streptococcus mitis 108, an isolate from the tooth surface of an infant, and showed that F-1 exhibited inflammatory cytokine-inducing activities. In the present study, we present evidence that fraction F-2 induced human T-cell proliferation in the presence of irradiated human peripheral blood mononuclear cells and selectively activated T cells bearing V beta 2 and V beta 5.1 in the T-cell receptor. F-1, on the other hand, stimulated human gingival fibroblasts to support the T-cell proliferation in the same way as human gamma interferon or Prevotella intermedia lipopolysaccharide (LPS). Fraction F-1 also primed gingival fibroblasts to support the production of interleukin-2 and gamma interferon by the T cells upon stimulation with F-2. Human gingival fibroblasts stimulated with fraction F-1, like those stimulated by P. intermedia LPS and human gamma interferon, exhibited human leukocyte antigen (HLA)-DR mRNA expression and cell surface HLA-DR molecules as detected by enzyme-linked immunosorbent assay. An anti-HLA-DR monoclonal antibody inhibited T-cell proliferation in response to F-2, probably through inactivating the accessory function of HLA-DR-bearing fibroblasts. T cells activated with F-2 in the presence of irradiated peripheral blood mononuclear cells exhibited definite cytotoxic effects against fibroblasts and squamous carcinoma cells originating from human oral tissues. These findings are strongly suggestive of an association of extracellular products of viridans streptococci with pathogenesis of oral mucosal diseases, particularly those disorders in gingiva which are accompanied by heavy infiltration of T cells.

Superantigenic exotoxin production by isolates of Staphylococcus aureus from the Kawasaki syndrome patients and age-matched control children

Nineteen strains of Staphylococcus aureus were isolated from the throat or the tooth surfaces of 19 cases amongst 127 patients with Kawasaki syndrome (KS) during the acute phases and 11 S. aureus isolates were obtained from five of 17 diseased controls and six healthy controls. The production of exotoxins, particularly superantigenic toxic shock syndrome toxin-1 (TSST-1), coagulase serotype, pigment production, haemolytic activity and tryptophan auxotrophy of these isolates were compared. Among 10 KS S. aureus strains isolated in 1990-1991, five (50%) secreted TSST-1, a higher frequency than two (18%) of 11 control isolates. In contrast, none of the nine KS strains collected in 1984 produced TSST-1. Four of five TSST-1-secreting KS strains produced white or white to golden pigmentation, whereas the two control strains capable of TSST-1 production formed golden colonies. There were no noticeable differences between S. aureus strains from KS patients and control children in the production of staphylococcal exotoxins A-E, coagulase serotype, haemolysis of sheep erythrocytes and tryptophan auxotrophy. The pathological or aetiological role of a new TSST-1-secreting S. aureus clone in patients with KS was not confirmed.

Guanidinoethane sulfate is neuroprotective towards delayed CA1 neuronal death in gerbils

The potential neuroprotective effects of guanidinoethane sulfate (GES) on delayed neuronal death of hippocampal CA1 neurons were investigated using a gerbil model of forebrain ischemia. Neuronal densities of CA1 neurons in the saline control group (255.1 +/- 11.7 cells/mm) and guanidinoethane sulfate pretreated control group (249.0 +/- 9.4 cells/mm) showed no significant differences. By contrast, in animals subjected to ischemia, CA1 neurons of the guanidinoethane sulfate pretreated group showed a significantly higher number of surviving neurons (61.1 +/- 55.11 cells/mm) compared to the saline group (17.75 +/- 12.73 cells/mm) (p < 0.05, t-test). The study indicated that although partial, guanidinoethane sulfate is neuroprotective towards gerbil hippocampal CA1 neurons against ischemic insult.

Doc2: a novel brain protein having two repeated C2-like domains

Two repeated C2-like domains interacting with Ca2+ and phospholipid are found in synaptotagmin and Rabphilin-3A which are implicated in neurotransmitter release. Here we have isolated a cDNA encoding a novel protein having two repeated C2-like domains from a human brain cDNA library. The isolated cDNA encodes a protein with 400 amino acids and a M(r) of 44,071. The purified recombinant protein indeed interacts with Ca2+ and phospholipid. We have named this protein Doc2 (Double C2). Doc2 is exclusively expressed in brain and is highly concentrated in the synaptic vesicle fraction. These results suggest that Doc2 is a novel brain protein and serves as a Ca2+ sensor in neurotransmitter release.

Occlusion of the right coronary artery as sequelae of Kawasaki disease: the clinical features of 9 cases

Among the 302 children with Kawasaki disease (KD) who were evaluated by angiography from 1973 through 1992, 9 (3.0%) had either an occlusion (OC) or segmental stenosis (SS) of the right coronary artery. The interval from the onset of KD to the recognition of OC or SS ranged from 0.5 to 7.7 years (median 4.0 years). Left coronary arterial lesions were also present in 8 of 9 patients. In spite of severe sequelae, children or young adolescents with cardiovascular system-related symptoms were unexpectedly rare. Asymptomatic patients, however, are also at risk of developing myocardial infarction since they have been shown to have a high rate of abnormalities on myocardial scintigraphy. A close observation and careful follow-up are thus considered to be indispensable.

Magnetic resonance imaging in the early diagnosis of cavernous sinus thrombosis

A 55-year-old man reported a severe headache of 3 days' duration, left ptosis and left lid swelling before examination. The ocular examination revealed left eye proptosis, severe edema of the left bulbar conjunctiva and lid, increasing intraocular pressure of the left eye and ptosis on the left side with decreased extraocular movement. The right eye was normal. Hematologic studies indicated mild inflammation. An enhanced computed tomography scan revealed proptosis of the left globe and enlargement of the superior ophthalmic vein and cavernous sinus of the left side. Angiography revealed an area of interrupted blood flow in the left cavernous sinus. Enhanced magnetic resonance imaging (MRI) with Gd-DTPA revealed a low-intensity area that was suspected to be a blood clot in the enlarged left cavernous sinus. This case indicates the efficacy of enhanced MRI examination in the early diagnosis of cavernous sinus thrombosis.

Changes in lens organophosphate metabolites in response to endotoxin-induced uveitis

Uveitis was induced in rats by endotoxin administration. The temporal correlation between ocular inflammatory reaction and lens metabolic change was examined. The levels of lens phosphate compounds, adenosine triphosphate (ATP), choline phosphate (CP), and inorganic phosphate (Pi), were measured using 31P-nuclear magnetic resonance (NMR) spectroscopy. Anterior chamber inflammation reaction appeared 12 h after administration, peaked at 24 h, and disappeared by 72 h. Concurrent with the active inflammation, lens Pi increased significantly 22 +/- 17% (p < 0.05) and 23 +/- 15% (p < 0.05), 12 and 24 h after administration, respectively, and returned to normal while the inflammation abated. No significant changes were observed in CP and ATP levels in the lens during the course of inflammation. The time course of the inflammation appeared closely related to the change in Pi level, which may be part of the protective mechanism of the lens against inflammation.

Autoantigen Ku protein is involved in DNA binding proteins which recognize the U5 repressive element of human T-cell leukemia virus type I long terminal repeat

We have identified and analyzed a 27-nucleotide sequence (U5 repressive element, designated as U5RE) at the U5 region of the human T-cell leukemia virus type I (HTLV-I) long terminal repeat (LTR) which is required for HTLV-I basal transcriptional repression. The basal promoter strength of constructs that contained deletions in the U5 region of the LTR was analyzed by chloramphenicol acetyltransferase (CAT) assays following transfection of HeLa cells or Jurkat T-cells in the presence or absence of viral transactivator tax protein. We consistently observed a 2- to 5-fold increase in basal promoter activity when sequences between +277 to +306 were deleted. In vivo competition experiments suggested that the U5 DNA fragment from +269 to +295 contains a functional repressive element (U5RE). Using gel mobility shift assays, we have purified a highly enriched fraction that could specifically bind U5RE. This DNA affinity column fraction contained three major detectable proteins on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with silver staining: 110-, 80- and 70-kDa proteins. The 110-kDa protein appeared to be a novel DNA-binding protein whose characteristics are still obscure, while the 70- and 80-kDa proteins were shown to be related to the human autoantigen Ku, the Ku (p70/p80) complex, as demonstrated by amino acid sequencing and immunological analyses. As Ku is known to be involved in transcriptional regulation, the specific interaction of Ku with U5RE raises intriguing possibilities for its function in HTLV-I basal transcriptional repression.

Time-of-flight MR angiography of portal system and collaterals in portal hypertension using a 2-DFT fast spoiled gradient recalled steady-state precession technique

MR angiographic examinations were performed in 26 patients. Approximately 30 contiguous fast spoiled GRASS images (8.1/3.1/30 degrees, TR/TE/flip angle) were acquired during single breath-holding for about 35 s, and then new images were reconstructed with maximum intensity projection technique. Spoiled GRASS images (40/12/40) of 2 to 3 slices were taken during breath-holding for about 13 s, and these processes were repeated to obtain about 30 individual images for conventional MR angiography. The new MR angiograms were compared quantitatively and qualitatively with conventional MR angiograms with arterial portography as the gold standard. The new MR angiograms could visualize blood vessels with smooth margins, and provided almost the same anatomic information about the portal vein and collateral vessels as the conventional MR angiograms. Contrast-to-noise ratios between the portal or hepatic vein and liver parenchyma were significantly higher with fast spoiled GRASS images. The new MR angiograms using fast spoiled GRASS images provided useful diagnostic mapping of the collateral venous pathways within a shorter examination time.