[An effective case of nitric oxide inhalation therapy in pulmonary hypertensive crisis in cardiopulmonary bypass following palliative operation for ventricular septal defect with pulmonary hypertension]

A 4-month-old female with ventricular septal defect (VSD) and severe pulmonary hypertension (PH) underwent a patch closure for VSD. She could not be weaned from cardiopulmonary bypass (CPB) after the intracardiac repair due to PH crisis. Nitric oxide inhalation therapy during partial CPB enabled her to be weaned from CPB. This therapy could be gradually taped off and quit 7 days after the operation. Nitric oxide inhaled therapy is considered to be an excellent treatment for PH crisis during CPB in congenital cardiac surgery. The causes of PH crisis were also discussed in reference to the date of endothelin-1 (ET-1) measured during the operation.

Ex vivo whole-embryo culture of caspase-8-deficient embryos normalize their aberrant phenotypes in the developing neural tube and heart

Caspase-8 plays the role of initiator in the caspase cascade and is a key molecule in death receptor-induced apoptotic pathways. To investigate the physiological roles of caspase-8 in vivo, we have generated caspase-8-deficient mice by gene targeting. The first signs of abnormality in homozygous mutant embryos were observed in extraembryonic tissue, the yolk sac. By embryonic day (E) 10.5, the yolk sac vasculature had begun to form inappropriately, and subsequently the mutant embryos displayed a variety of defects in the developing heart and neural tube. As a result, all mutant embryos died at E11.5. Importantly, homozygous mutant neural and heart defects were rescued by ex vivo whole-embryo culture during E10.5-E11.5, suggesting that these defects are most likely secondary to a lack of physiological caspase-8 activity. Taken together, these results suggest that caspase-8 is indispensable for embryonic development.

Mechanism of selective inhibition of respiratory syncytial virus by a benzodithiin compound (RD3-0028)

RD3-0028, a compound with a benzodithiin structure, was found to be a potent inhibitor of respiratory syncytial virus (RSV) replication. Its action is specific; no activity is seen against influenza A virus, measles virus, herpes simplex virus type 1 or 2, or human cytomegalovirus. A time-dependent drug addition experiment indicated that the antiviral activity occurs in the late stage of the RSV replication cycle, since this compound completely inhibited syncytium formation even when added up to 16 hr after the infection of cell monolayers at an MOI of 3. RD3-0028 had no direct virucidal effect on RSV. Western blotting analysis showed that RD3-0028 significantly decreased the amount of RSV proteins released into the cell culture medium. Moreover, five independent isolates of the RSV long strain were selected for growth in RD3-0028 (5-20 microg/ml). These resistant viruses were more than 80-fold less sensitive to RD3-0028 than the long strain. The F gene segment of each of these viruses was sequenced and in each case the mutant RNA segment contained at least one sequence alteration, converting asparagine 276 to tyrosine (F1 protein). These results suggest that RD3-0028 inhibits RSV replication by interfering with intracellular processing of the RSV fusion protein, or a step immediately thereafter, leading to loss of infectivity.

Pharmacokinetics of a benzodithiin (RD3-0028) following aerosol treatment in rat

1. RD3-0028, a benzodithiin compound, has potent antiviral activity against respiratory syncytial virus (RSV) in cell culture. The compound also inhibits growth of RSV and improves pathologic changes of interstitial pneumonia in the immunosuppressed mouse when delivered by small-particle aerosol. 2. In the present study, the absorption, distribution and excretion of 14C-RD3-0028 were compared in rat following either a single aerosol treatment or oral administration. 3. The plasma concentration was maintained at the same level from 5 min to 1 h, and decreased with a half-life of 2.2 +/- 0.1 h for 1-8 h. 4. The excretion of radioactivity in the urine and faeces at 24 h after aerosol treatment was 89.3 and 4.5%, respectively, indicating that almost all the radioactivity was rapidly excreted in the urine. The excretion of total radioactivity was 98.9% within 168 h. 5. The concentrations of radioactivity in the lung and trachea following aerosol treatment were higher than those in other tissues, and were detected even at 72 h. 6. These results suggest that the aerosol treatment might be useful for delivering RD3-0028 to the respiratory tract of RSV-infected patients.

IL-1 alpha, but not IL-1 beta, is required for contact-allergen-specific T cell activation during the sensitization phase in contact hypersensitivity

Contact hypersensitivity (CHS) is a T cell-mediated cellular immune response caused by epicutaneous exposure to contact allergens. In this reaction, after the first epicutaneous allergen sensitization, Langerhans cells (LC) catch allergens and migrate from the skin to draining lymph nodes (LN) and activate naive T cells. Although IL-1 is suggested to be involved in these processes, the mechanisms have not been elucidated completely. In this report, to elucidate roles of IL-1alpha and IL-1beta in CHS, we analyzed ear swelling in 2,4,6-trinitrochlorobenzene (TNCB)-induced CHS using gene-targeted mice. We found that ear swelling was suppressed in IL-1alpha-deficient (IL-1alpha(-/-)) mice but not in IL-1beta(-/-) mice. LC migration from the skin into LN was delayed in both IL-1alpha(-/-) and IL-1beta(-/-) mice, suggesting that this defect was not the direct cause for the reduced CHS in these mice. However, we found that the proliferative response of trinitrophenyl (TNP)-specific T cells after sensitization with TNCB was specifically reduced in IL-1alpha(-/-) mice. Furthermore, adoptive transfer of TNP-conjugated IL-1-deficient epidermal cells (EC) into wild-type mice indicated that only IL-1alpha, but not IL-1beta, produced by antigen-presenting cells in EC could prime allergen-specific T cells. These observations indicate that IL-1alpha, but not IL-1beta, plays a crucial role in TNCB-induced CHS by sensitizing TNP-specific T cells.

Plaque-like structures and arteriosclerotic changes in "diffuse neurofibrillary tangles with calcification" (DNTC)

"Diffuse neurofibrillary tangles with calcification" (DNTC) is a rare form of slowly progressive dementia characterized by temporal or fronto-temporal atrophy with neuronal loss and astrocytosis, neurofibrillary tangles and Fahr-type calcification, but no senile plaques in the cerebral cortex. In patients with DNTC, we detected a novel histopathological abnormality that we termed "plaque-like structures" (PLS). PLS appeared as oval, slightly eosinophilic masses of up to 100 microns in diameter. With methenamine silver stain, the PLS were argyrophilic, and thread-like structures were observed in and around them. Most PLS were observed in deep layers of the cortex and subcortical white matter, and were accompanied by small vessels. They were intimately associated with the small-vessel walls and astrocytes. They were composed of two types of fibers. The first type comprised straight and loosely interwoven fibers about 25-30 nm in diameter, while the other type evoked tangles. These structures have not been found in other neurodegenerative diseases, including Alzheimer's disease. In addition, to evaluate hyaline arteriosclerosis in DNTC, we examined sclerotic changes of the medullary arteries and assessed white matter lesions in affected patients. In three of four patients with DNTC, sclerosis of the medullary arteries was significantly more extensive than in age-matched controls. In all four patients, the severity of white matter lesions was graded as moderate or severe in the temporal lobe and as mild or moderate in the frontal lobe. Arteriosclerotic changes and white matter lesions can occur without hypertension and beta amyloid deposits in DNTC.

Warthin-like tumor variant of papillary thyroid carcinoma: case report and literature review

A tumor approximately 4.0 x 3.0 cm in size with a cystic change was observed in the left lobe of the thyroid gland of a 52-year-old woman. The removed tumor had lymph follicle formation with a germinal center. This lymphatic tissue showed papillary and island-like growth; the growths were surrounded by atypical epithelium showing nuclear features of papillary carcinoma. The atypical epithelium had ground-glass nuclei with nuclear grooves, clearly indicating intranuclear cytoplasmic inclusion bodies. No chronic thyroiditis was observed in the background of the patient. Parts of the metastatic lymph nodes had cells with an eosinophilic cytoplasm, clearly showing an intratumor lymph follicle formation, as in the primary lesion. This is a rare case of thyroid papillary carcinoma similar to Warthin's tumor of the salivary gland. Here we present this case, with a review of previously published reports.

Quantitative assessment of the stem cell self-renewal capacity

Little is known about the manner in which hematopoietic stem cells (HSCs) self-renew. To address this issue, we used a serum-free single-cell culture, followed by transplantation of cultured cells into lethally irradiated mice. CD34-negative or low, c-Kit-positive, Sca-1-positive, lineage marker-negative (CD34-KSL) cells are highly enriched for murine bone marrow HSCs. Successful long-term reconstitution with a single CD34-KSL cell enabled us to study in vitro self-renewal of HSC at clonal level. Using this clonal cell transplantation system, we examined the effect of various cytokines on CD34-KSL cells. Among the cytokines examined, stem cell factor (SCF) and thrombopoietin (TPO) were minimum cytokines to induce cell division of CD34-KSL cells most efficiently. Similarly, multilineage repopulating activity was detected in the cells derived from a significant portion of single cells after culture in the presence of TPO and SCF. However, SCF + IL-3, SCF + IL-6, or SCF + IL-11 + FL appeared to be less effective for self-renewal of HSCs. The activity of HSCs as indicated by repopulation unit (RU) remaining after culture with SCF and TPO was not so different from that of freshly isolated HSCs. However, there was a substantial loss of HSC number in these cultured cells. Taken together, this study provides definitive proof that one HSC can generate at least one HSC in vitro.

A modified "elephant trunk" procedure for aortic arch replacement

OBJECTIVES

We have devised a modified "elephant trunk" technique for primary aortic arch replacement that strengthens the distal anastomosis by preventing access of the blood stream to the distal suture line. The technique entails suturing an elephant trunk graft to the inner surface of the arch graft circumferentially just distal to the fourth of its 4 limbs. The inner graft is then inserted into the distal aortic lumen while the edge of the arch graft orifice is anastomosed to the aortic stump. This clinical trial was conducted to clarify its usefulness.

METHODS

This technique was used in 5 cases of total arch replacement to reinforce distal anastomoses.

RESULTS

All patients tolerated surgery well without complications such as paraplegia or thromboembolism.

CONCLUSIONS

The advantages of this modified technique include simplicity and reproducibility.

Six4, a putative myogenin gene regulator, is not essential for mouse embryonal development

Six4 is a member of the Six family genes, homologues of Drosophila melanogaster sine oculis. The gene is thought to be involved in neurogenesis, myogenesis, and development of other organs, based on its specific expression in certain neuronal cells of the developing embryo and in adult skeletal muscles. To elucidate the biological roles of Six4, we generated Six4-deficient mice by replacing the Six homologous region and homeobox by the beta-galactosidase gene. 5-Bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining of the heterozygous mutant embryos revealed expression of Six4 in cranial and dorsal root ganglia, somites, otic and nasal placodes, branchial arches, Rathke's pouch, apical ectodermal ridges of limb buds, and mesonephros. The expression pattern was similar to that of Six1 except at the early stage of embryonic day 8.5. Six4-deficient mice were born according to the Mendelian rule with normal gross appearance and were fertile. No hearing defects were detected. Six4-deficient embryos showed no morphological abnormalities, and the expression patterns of several molecular markers, e.g., myogenin and NeuroD3 (neurogenin1), were normal. Our results indicate that Six4 is not essential for mouse embryogenesis and suggest that other members of the Six family seem to compensate for the loss of Six4.

TAG-1-deficient mice have marked elevation of adenosine A1 receptors in the hippocampus

TAG-1 is a neural recognition molecule in the immunoglobulin superfamily that is predominantly expressed in the developing brain. Several lines of evidence suggest that TAG-1 is involved in the outgrowth, guidance, and fasciculation of neurites. To directly assess the function of TAG-1 in vivo, we have generated mice with a deletion in the gene encoding TAG-1 using homologous recombination in embryonic stem cells. Gross morphological analysis of the cerebellum, the spinal cord, and the hippocampus appeared normal in TAG-1-deficient mice. However, TAG-1 (-/-) mice showed the upregulation of the adenosine A1 receptors determined by [(3)H]cyclopentyl-1,3-dipropylxanthine in the hippocampus, and their greater sensitivity to convulsant stimuli than that in TAG-1 (+/+) mice. We suspect that the subtle changes in neural plasticity induced by TAG-1 deficiency during development cause the selective vulnerability of specific brain regions and the epileptogenicity in TAG-1 (-/-) mice.

In vitro self-renewal division of hematopoietic stem cells

Little is known about how hematopoietic stem cells (HSCs) self-renew. We studied the regeneration of HSCs in culture. Effects of various cytokines on cell division of CD34(-/low) c-Kit(+)Sca-1(+) lineage marker-negative (CD34(-)KSL) bone marrow cells of the mouse were first evaluated in serum-free single cell culture. We then performed a competitive repopulation assay on divided cells to ask if such cell division involved self-renewal of HSCs. In the presence of stem cell factor (SCF), thrombopoietin (TPO) induced a first cell division of CD34(-)KSL cells more efficiently than did interleukin (IL)-3 or IL-6. Multilineage repopulating cells were detected in a significant proportion of cells derived from single cells in culture with TPO and SCF, although this culture condition led to a substantial decrease in HSC number. These regenerated repopulating cells could be further transplanted into secondary recipients. When paired daughter cells were separately studied, one of a pair gave rise to repopulating cells with self-renewal potential, suggesting asymmetric self-renewal division. This study provides evidence that one HSC regenerates at least one HSC in culture.

Age-associated characteristics of murine hematopoietic stem cells

Little is known of age-associated functional changes in hematopoietic stem cells (HSCs). We studied aging HSCs at the clonal level by isolating CD34(-/low)c-Kit(+)Sca-1(+) lineage marker-negative (CD34(-)KSL) cells from the bone marrow of C57BL/6 mice. A population of CD34(-)KSL cells gradually expanded as age increased. Regardless of age, these cells formed in vitro colonies with stem cell factor and interleukin (IL)-3 but not with IL-3 alone. They did not form day 12 colony-forming unit (CFU)-S, indicating that they are primitive cells with myeloid differentiation potential. An in vivo limiting dilution assay revealed that numbers of multilineage repopulating cells increased twofold from 2 to 18 mo of age within a population of CD34(-)KSL cells as well as among unseparated bone marrow cells. In addition, we detected another compartment of repopulating cells, which differed from HSCs, among CD34(-)KSL cells of 18-mo-old mice. These repopulating cells showed less differentiation potential toward lymphoid cells but retained self-renewal potential, as suggested by secondary transplantation. We propose that HSCs gradually accumulate with age, accompanied by cells with less lymphoid differentiation potential, as a result of repeated self-renewal of HSCs.

Pharmacokinetics and adverse events following 5-day repeated administration of lenograstim, a recombinant human granulocyte colony-stimulating factor, in healthy subjects

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) (lenograstim) was administered to healthy subjects at doses of 2, 5 and 10 micrograms/kg/day for 5 days (twice a day subcutaneously) to examine the optimal dose and schedule of lenograstim in mobilizing peripheral blood progenitor cells (PBSC) for allogeneic transplantation. Lenograstim administration significantly increased CD34+ cells in a dose-related manner. A significant correlation was observed between the maximal post-dosing counts and the pre-dosing baseline counts of CD34+ cells. Peripheral neutrophils increased markedly by seven to 13 times from the baseline to a peak of approximately 40,000/microliter on day 5 for the 5 and 10 micrograms/kg/day doses. After peak serum concentration (Cmax) was attained 4 h following administration, serum G-CSF declined with time in a log-linear fashion. The Cmax and 12 h area-under-the-curve increased dose dependently, but minimum drug level increased up to day 2 and then decreased until day 5. Clearance decreased with increasing dosage at the first dose, and increased significantly at the last dose. We found a highly significant correlation between absolute neutrophil counts and clearance for each dose. Adverse events most frequently occurred on day 6, with increases of alkaline phosphatase and lactate dehydrogenase and onset of bone pain. Increases of aspartate aminotransferase and alanine aminotransferase occurred as delayed events. Platelet count gradually decreased after the end of drug administration to 57% of the pre-dosing count on day 10, but was still within the normal range. These preliminary results suggest that repeated doses of lenograstim induce mobilization of PBSC in a dose-dependent manner and the pre-dosing baseline count of PBSC may predict the post-dosing maximal mobilization. The drug treatment may cause delayed-onset moderate thrombocytopenia and increased transaminase, and the drug clearance changes in a complex manner during repeated dosing.

Late leaflet fracture and embolization of a Duromedics mitral prosthesis

A case of leaflet fracture and embolization of a mitral prosthetic valve is described. A 54-year-old man had received mitral valve replacement with an Edwards-Duromedics 29M prosthetic valve, at 10 years ago. Emergency mitral valve replacement was performed because the patient had severe congestive left heart failure with severe acute mitral regurgitation caused by a fracture in one of the mitral valve leaflets. The leaflet, which was fractured into 2 pieces, was removed from the right common iliac artery at 3 months after valve replacement. Visual inspection revealed that the leaflet contained a midline fracture. The fracture originated within a cavitary erosion pit near the major radius of the leaflet. The patient recovered from acute renal failure, requiring hemodialysis for 80 days, and is currently without complaints. We have used a Duromedics mitral valve in 11 patients, from April 1987 to April 1988. No subsequent valve failure has occurred. The diagnosis, treatment and cause of a mechanical valve fracture are discussed.

Mutually exclusive expression of odorant receptor transgenes

To study the mutually exclusive expression of odorant receptor (OR) genes, we generated transgenic mice that carried the murine OR gene MOR28. Expression of the transgene and the endogenous MOR28 was distinguished by using two different markers, beta-galactosidase and green fluorescent protein (GFP), respectively. Double staining of the olfactory epithelium revealed that the two genes were rarely expressed simultaneously in individual olfactory neurons. A similar exclusion was also observed between differently tagged but identical transgenes integrated into the same locus of one particular chromosome. Although allelic inactivation has been reported for the choice between the maternal and paternal alleles, this is the first demonstration of mutually exclusive activation among non-allelic OR gene members with identical coding and regulatory sequences. Such an unusual mode of gene expression, monoallelic and mutually exclusive, has previously been shown only for the antigen-receptor genes of the immune system.

Dominant expansion of human T cells in non-obese diabetic/severe combined immunodeficiency mice implanted with human bone fragments

OBJECTIVE

To establish an in vivo animal model in which human T cells develop and function normally, a step toward developing new vaccines or chemical compounds that modulate immune functions and toward understanding T-cell immunity in humans.

MATERIALS AND METHODS

Human bone fragments were implanted into non-obese diabetes/severe combined immunodeficiency (NOD/SCID) mice. The presence of human blood cells in the peripheral blood of these mice was monitored periodically by immunostaining and fluorescence-activated cell sorting.

RESULTS

After implantation of bone fragments, dominant expansion of human T lymphocytes, rather than myeloid and B cells, was observed over a 3-month period. In some cases, the proportion of human T cells rose to 40% of the peripheral blood mononuclear cells. These T cells showed CD4/CD8 ratios similar to those observed in human peripheral blood lymphocytes and had a broad repertoire of rearranged T-cell receptor genes. Graft-versus-host reaction was not noted in any organ analyzed. To assess the suitability of NOD/SCID mice implanted with human bone fragments (hu-bone-NOD/SCID mice) as an in vivo model for HIV infection, the mice were infected with a T-lymphotropic strain of HIV-1 (NL4-3) at 7 weeks posttransplant. Serum p24 gag was detected at 2 weeks after inoculation, after which total CD4-positive cell numbers declined, as seen clinically in patients infected with HIV.

CONCLUSION

Although the precise mechanism is yet to be determined by which predominant expansion of human T cells occurs in hu-bone-NOD/SCID mice, such mice appear likely to serve as a useful and versatile model for studies involving human T-cell immunity.

Reoperative coronary artery bypass via left thoracotomy

The patient was a 49-year-old woman. When she was 39 years old, she underwent coronary artery bypass grafting (left internal thoracic artery to left anterior descending artery, saphenous vein graft to first diagonal branch). At the age 48, she had effort angina. On coronary angiography, triple-vessel disease was found, and she was treated conservatively. Progression of the disease was confirmed with detection of the left circumflex artery associated with jeopardized collateral to the right coronary artery showing total occlusion. The patient underwent reoperation. Since the left internal thoracic artery was patent despite occlusion of the saphenous vein graft, the approach of left thoracotomy was employed. Under cardiopulmonary bypass with ventricular fibrillation and left vent through left atrial appendage, the right radial artery was anastomosed to the left circumflex artery from the descending thoracic aorta, and the right gastroepiploic artery was anastomosed to the right coronary artery (4AV branch). Patency of the bypass was confirmed postoperatively. We consider this operative technique was especially useful for reoperation in cases of a patent internal thoracic artery in which left thoracotomy can be conducted safely.

[HIV-1 (human immunodeficiency virus type 1) mutant strain associated with zidovudine resistance detected from a Japanese patient with primary HIV-1 infection]

Sequences of HIV-1 pol gene were determined by direct sequencing from a Japanese patient with primary HIV-1 infection. The patient did not receive antiretroviral therapies. However we observed a HIV-1 mutant strain associated with zidovudine (ZDV) resistance. The patient had both the codon 70 and the codon 215 amino acid substitutions in the RT region. Our data indicated that the patient was infected with a HIV-1 mutant strain associated with ZDV resistance and this is the first report in Japan.