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.

[A case of muscle metastasis of renal cell carcinoma treated by local resection and tensor fascia lata myocutaneous flaps]

A 44-year-old male with a little finger tip-sized tumor palpable on the left epigastric wall and a left renal tumor detected on computerized tomography (CT) was referred to this hospital in June 1991. Nephrectomy was performed in July 1991 under the diagnosis of a left renal tumor. Histologically, the tumor was a renal cell carcinoma, grade 2, clear and granular cell type. The tumor in the left abdominal wall was not extracted. As a tumor also developed in the scapular tunica muscularis, tumors in the left musculus rectus abdominis and the scapular tunica muscularis were extracted to the extent possible in July of 1992. Histologically, these tumors were metastatic clear cell carcinomas. The tumor in the left musculus rectus abdominis recurred and another was palpable in the left lateral femur. In August of 1993, the tumors in the left musculus vastus lateralis and the left musculus abdominis were extracted together with the tunica muscularis, and the defective region on the abdominal wall was closed with a left musculus tensor fascia lata flap. No evidence of recurrence has been observed to date.

Clonal expansion but lack of subsequent clonal deletion of bacterial superantigen-reactive T cells in murine retroviral infection

Several studies have suggested that activation-induced apoptosis of Ag-specific CD4+ T cells leads to depletion of this subset during HIV infection. The bacterial superantigen, staphylococcal enterotoxin A (SEA), is known to induce activation-induced apoptosis in the TCR V beta-bearing CD4+ T cells in the periphery after clonal expansion of these cells. The murine retroviral model of AIDS (MAIDS), which is induced by LP-BM5 murine leukemia virus, shares many common features with HIV infection in humans, except that CD4+ T cells increase progressively in susceptible strains. In this study, we challenged SEA to MAIDS mice and examined whether this retrovirus affects the fate of the SEA-reactive CD4+ T cells in vivo. At 4 wk post-infection with LP-BM5 murine leukemia virus, clonal expression and subsequent deletion of SEA-reactive CD4+V beta 3+ T cells occurred normally after SEA administration, whereas in vitro proliferative responses were severely impaired. At 8 wk postinfection, the in vivo expansion of CD4+V beta 3+ T cells was evident, but not followed by clonal deletion, as late as 14 days after SEA administration. This expanding subset in the infected mice expressed the Fas Ag in the same amount as the same subset in uninfected controls. These findings suggest that activation-induced apoptosis of superantigen-reactive CD4+ T cells is interfered with in vivo during the course of MAIDS, which is not attributable to underexpression of the Fas Ag by the CD4+ T cells.

Clonal expansion but lack of subsequent clonal deletion of bacterial superantigen-reactive T cells in murine retroviral infection

Several studies have suggested that activation-induced apoptosis of Ag-specific CD4+ T cells leads to depletion of this subset during HIV infection. The bacterial superantigen, staphylococcal enterotoxin A (SEA), is known to induce activation-induced apoptosis in the TCR V beta-bearing CD4+ T cells in the periphery after clonal expansion of these cells. The murine retroviral model of AIDS (MAIDS), which is induced by LP-BM5 murine leukemia virus, shares many common features with HIV infection in humans, except that CD4+ T cells increase progressively in susceptible strains. In this study, we challenged SEA to MAIDS mice and examined whether this retrovirus affects the fate of the SEA-reactive CD4+ T cells in vivo. At 4 wk post-infection with LP-BM5 murine leukemia virus, clonal expression and subsequent deletion of SEA-reactive CD4+V beta 3+ T cells occurred normally after SEA administration, whereas in vitro proliferative responses were severely impaired. At 8 wk postinfection, the in vivo expansion of CD4+V beta 3+ T cells was evident, but not followed by clonal deletion, as late as 14 days after SEA administration. This expanding subset in the infected mice expressed the Fas Ag in the same amount as the same subset in uninfected controls. These findings suggest that activation-induced apoptosis of superantigen-reactive CD4+ T cells is interfered with in vivo during the course of MAIDS, which is not attributable to underexpression of the Fas Ag by the CD4+ T cells.

B cell Ag receptor mediates different types of signals in the protein kinase activity between immature B cell and mature B cell

Ig receptor (IgR) on the surface of B cells mediates the Ag-specific stimulatory signal for B cell proliferation and differentiation. In immature B cells, the stimulatory signal causes an inhibitory effect which is believed to be a key phenomenon in B cell tolerance or B cell anergy. Here, we studied the molecular mechanism of the inhibitory response of the IgR-mediated signal transduction that results in the programmed cell death of immature B cells. To analyze the downstream molecules of the IgR-mediated signal transduction, we prepared a mAb against a 160-kDa membrane protein (p160) that can coprecipitate the kinase molecule(s) acting on serine, threonine, and tyrosine residues. Anti-IgR stimulation induces the increase of the kinase activity coprecipitated with the p160 protein in mature B cell BAL17 and normal adult spleen B cells. This result suggest that the p160-associated kinase activity is one of the downstream events of the IgR-mediated signal transduction cascade. Interestingly, immature B cell lymphoma WEHI-231 and the neonatal spleen B cells showed the adverse reaction of the p160-associated kinase which results in the transient loss of the kinase activity. Moreover, the transient decrease of the p160-associated kinase was caused by the tyrosine phosphatase activity induced by the stimulation of IgR in WEHI-231. The results suggest that this molecular difference in the downstream events of the IgR-mediated signal transduction between immature B cells and mature B cells already begins at the transmembrane level in the IgR-mediated signal transduction pathway.

B cell Ag receptor mediates different types of signals in the protein kinase activity between immature B cell and mature B cell

Ig receptor (IgR) on the surface of B cells mediates the Ag-specific stimulatory signal for B cell proliferation and differentiation. In immature B cells, the stimulatory signal causes an inhibitory effect which is believed to be a key phenomenon in B cell tolerance or B cell anergy. Here, we studied the molecular mechanism of the inhibitory response of the IgR-mediated signal transduction that results in the programmed cell death of immature B cells. To analyze the downstream molecules of the IgR-mediated signal transduction, we prepared a mAb against a 160-kDa membrane protein (p160) that can coprecipitate the kinase molecule(s) acting on serine, threonine, and tyrosine residues. Anti-IgR stimulation induces the increase of the kinase activity coprecipitated with the p160 protein in mature B cell BAL17 and normal adult spleen B cells. This result suggest that the p160-associated kinase activity is one of the downstream events of the IgR-mediated signal transduction cascade. Interestingly, immature B cell lymphoma WEHI-231 and the neonatal spleen B cells showed the adverse reaction of the p160-associated kinase which results in the transient loss of the kinase activity. Moreover, the transient decrease of the p160-associated kinase was caused by the tyrosine phosphatase activity induced by the stimulation of IgR in WEHI-231. The results suggest that this molecular difference in the downstream events of the IgR-mediated signal transduction between immature B cells and mature B cells already begins at the transmembrane level in the IgR-mediated signal transduction pathway.

The gene encoding a new mitogenic factor in a Streptococcus pyogenes strain is distributed only in group A streptococci

We recently cloned a gene encoding a new mitogenic factor (MF) from Streptococcus pyogenes NY-5. In the present study, we determined the distribution of this MF gene (mf) by PCR based upon its sequence. Of 371 streptococcal group A strains isolated from clinical specimens, 370 (99.7%) were positive for mf. The strain that was negative for the MF gene was also negative for the streptolysin O gene (slo). Some streptococcal strains belonging to groups C and G were negative for mf but positive for slo. Group B strains were negative for both. Furthermore, we examined the presence of mf in 54 strains belonging to 28 families and found mf only in group A streptococci. These results indicate that mf is distributed specifically in group A streptococci and the presence of mf in clinical samples strongly suggests infection with group A streptococci.

Brain maturation and high-energy phosphate diffusivity: alteration in cytosolic microenvironment and effective viscosity

Maturational changes in intracellular brain phosphocreatine (PCr) transport were investigated using 31P-nuclear magnetic resonance diffusion spectroscopy. The diffusivities of PCr showed significant maturational facilitation in rat brain in vivo. Physicochemical analysis of the cytosol microenvironment as a multicomponent solution, where one of the components is a dilute polymer, indicated that the observed developmental facilitation of PCr diffusivity is likely to be due to a decline in the concentration of the free amino acid taurine. Changes in the concentrations of biopolymers (i.e., proteins or lipids) have only little effect, if any, on PCr diffusivity. PCr diffusivity values of rat brain measured in vivo showed excellent quantitative agreement with the predicted values estimated using a model for multicomponent diffusion. The study confirmed that the taurine/N-acetylaspartate exchange observed during postnatal development of rat brain plays a major, it not unique, role in maturational facilitation of intracellular high-energy phosphate transport.

A novel saturation transfer contrast method for 3D time-of-flight magnetic resonance angiography: a slice-selective off-resonance sinc pulse (SORS) technique

Saturation transfer contrast (STC) techniques have been employed to decrease the signal intensity of observed water by saturating a broad proton component. The STC pulse, generally spatially nonselective, reduces the signal of brain background tissues as well as inflowing blood in 3D time-of-flight (TOF) angiography. We present a novel technique, a slice-selective off-resonance sinc pulse (SORS), which is employed to enhance inflowing blood and to suppress the signal of stationary background tissues. The STC effects of the SORS and other spatially nonselective methods influencing inflowing blood is discussed in detail. Angiograms using the SORS method are also presented to demonstrate improved vessel conspicuity. In addition, the SORS method is applicable to imagers with a whole-body RF transmitter system.