[Polymyositis-induced respiratory failure in the presence of antecedent pleural effusion]

Pulmonary involvement is generally recognized to be an important determinant of the clinical course in cases of polymyositis. A patient with bilateral pleural effusion as an initial symptom developed respiratory failure due to muscle weakness. Polymyositis was diagnosed on the basis of a muscle biopsy. A chemotherapy regimen consisting of methyl prednisolone (1 g/day for 3 days) followed by prednisolone (60 mg/day) alleviated, the pleural effusion and respiratory failure. Though pleural complications in polymyositis have been described mostly in association with concomitant interstitial lung disease, our patient exhibited only bilateral pleural effusion. Given that pleural effusion can be an initial symptom of polymyositis, it seems necessary that polymyositis be taken into consideration by differential diagnoses of pleural effusion of unknown etiology.

Adaptation of equine herpesvirus 1 to unnatural host led to mutation of the gC resulting in increased susceptibility of the virus to heparin

Heparin extensively inhibited infection of MDBK cells by equine herpesvirus 1 (EHV-1) strains adapted to bovine cells or hamsters, while the reagent merely reduced infectivity of strains passaged only in equine cells. The gC of two strains adapted to non-equine cells seemed to have higher affinity for heparin, although the reagent bound to both the gC and gB of all strains tested. Amino acid substitutions of the gC of the EHV-1 strains adapted to non-equine cells converged on the hydrophilic regions, amino acid residues 92 to 175, resulting in the glycoprotein becoming more cationic. These results indicate that these hydrophilic regions of the gC may be responsible for binding to heparin.

[A case of thoracic extradural spinal cord teratoma with neurological sequelae more than 10 years after surgery]

We describe a rare case of a 42-year-old man with extradural spinal cord teratoma who presented with left Brown-Séquard syndrome more than 10 years after surgery for a left posterior mediastinal tumor. When he was 29 years old, he underwent an operation for a posterior mediastinal tumor. Histological findings showed adenocarcinoma in teratoma. Ten years after the operation, the patient developed left leg weakness. Three years later, he developed superficial sensory disturbance in his right leg. MRI showed extradural tumor formation at the level of the Th 9 vertebra, which compressed the spinal cord from the left posterior side. At surgery, the tumor was well encapsulated and extended to the left posterior side of the spinal cord through the intervertebral foramen. The histological findings were almost identical to those from the mediastinal tumor. This dumbbell tumor apparently developed from the remainder of the posterior mediastinal tumor over a period of more than 10 years.

Methylprednisolone pulse therapy in two clinical types of crescentic glomerulonephritis

To clarify the effectiveness of methylprednisolone pulse therapy on crescentic glomerulonephritis (CresGN), data of 46 patients was retrospectively studied. According to the slope of reciprocals of serum creatinine (s-Cr) the patients were divided into acute and insidious types, and each type was further divided into pulse (P) and conventional (C) therapy groups. In group C, s-Cr improved more frequently in the acute type (8/10) than in the insidious type (1/9, p<0.05), and the renal survival rate was somewhat higher in the former (p=0.09). In the acute type there was no difference in the improvement rate of s-Cr between the two therapy groups, whereas in the insidious type, the improvement rate was higher in group P (9/15) than in group C (1/9, p<0.05) and the renal survival rate was higher in the former (p<0.01). These results suggest that methylprednisolone pulse therapy may be highly effective for the insidious type of CresGN.

Spread of colorectal cancer micrometastases in regional lymph nodes by reverse transcriptase-polymerase chain reactions for carcinoembryonic antigen and cytokeratin 20

BACKGROUND AND OBJECTIVES

Lymph node metastasis is known as a significant predictor of prognosis in colorectal cancer patients. Recently, reverse transcriptase polymerase chain reaction (RT-PCR) has been applied to detecting micrometastasis. To assess the risk of recurrence and accurately determine the spread of tumor cells, we examined lymph node micrometastases in a series of colorectal cancer patients.

METHODS

We examined 202 lymph nodes obtained from 13 colorectal cancer patients who underwent curative operation and were histologically diagnosed to be node-negative, using RT-PCR to amplify mRNAs for two epithelial markers, carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20).

RESULTS

All the cases, including early stage patients, had micrometastases. A total of 102 among 202 lymph nodes (50.5%) were positive for either CEA or CK-20, or both (47.0, 40.1, and 36.6% respectively). Positive lymph nodes were spread along the courses of vascular trunks as well as being located in more distant regions.

CONCLUSIONS

Even in histologically negative lymph nodes, there is a considerable possibility that micrometastases may exist. Their detection by RT-PCR may improve clinical staging and indications for cancer therapy. We should also take care in the choice of surgical approach.

Metabolism and pharmacokinetics of orally administered saikosaponin b1 in conventional, germ-free and Eubacterium sp. A-44-infected gnotobiote rats

The metabolic fate of saikosaponin b1 (1) was investigated using conventional, germ-free and Eubacterium sp. A-44-infected gnotobiote rats. After the oral administration of 1 to germ-free rats at a dose of 50 mg/kg, no metabolite was detected in the plasma, the cecal contents or the cumulative feces through the experiment. On the other hand, when 1 was orally given to the Eubacterium sp. A-44-infected gnotobiote rats, considerable amounts of its metabolites, prosaikogenin A (2) and saikogenin A (3), were detected in the rat plasma with the respective AUC0-10 h values of 17,424 and 22,260 pmol.min/ml, similar to the case of its oral administration to conventional rats (AUC0-10 h values of 9,936 and 12,414 pmol.min/ml for 2 and 3, respectively). Furthermore, significant amounts of both metabolites were detected in the cecal contents and the cumulative feces of the gnotobiote and conventional rats, but not in those of the germ-free rats, within 10 h after the administration. Fecal and cecal activities of hydrolyzing 1 and 2 were found in the gnotobiote and conventional rats, though there were no detectable activities in the germ-free rats. Accordingly, both hydrolyzing activities in the intestinal bacteria, such as Eubacterium sp. A-44, are essential for the appearance of 2 and 3 in the rat plasma and cumulative feces, since orally administered 1 was poorly absorbed from the gastrointestinal tract.

Spread of colorectal cancer micrometastases in regional lymph nodes by reverse transcriptase-polymerase chain reactions for carcinoembryonic antigen and cytokeratin 20

BACKGROUND AND OBJECTIVES

Lymph node metastasis is known as a significant predictor of prognosis in colorectal cancer patients. Recently, reverse transcriptase polymerase chain reaction (RT-PCR) has been applied to detecting micrometastasis. To assess the risk of recurrence and accurately determine the spread of tumor cells, we examined lymph node micrometastases in a series of colorectal cancer patients.

METHODS

We examined 202 lymph nodes obtained from 13 colorectal cancer patients who underwent curative operation and were histologically diagnosed to be node-negative, using RT-PCR to amplify mRNAs for two epithelial markers, carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20).

RESULTS

All the cases, including early stage patients, had micrometastases. A total of 102 among 202 lymph nodes (50.5%) were positive for either CEA or CK-20, or both (47.0, 40.1, and 36.6% respectively). Positive lymph nodes were spread along the courses of vascular trunks as well as being located in more distant regions.

CONCLUSIONS

Even in histologically negative lymph nodes, there is a considerable possibility that micrometastases may exist. Their detection by RT-PCR may improve clinical staging and indications for cancer therapy. We should also take care in the choice of surgical approach.

[Effect of the continuous epidural buprenorphine injection in patients after lower extremity arthroplasty]

We studied the analgesic effects of continuous epidural injection of buprenorphine in patients after lower extremity arthroplasty. In these patients anesthesia was maintained only with lumbar epidural anesthesia with 2% mepivacaine. We employed a balloon type continuous infuser (DIB Catheter, 40 ml.day-1) for postoperative analgesia for twenty-four hours. The patients were classified into three groups according to the method of buprenorphine injection and the content of DIB Catheter. First group (group A ; N = 37) received buprenorphine (0.2 mg) with 0.25% bupivacaine (40 ml) for twenty-four hours. Next group (group B ; N = 27) received bolus injection of buprenorphine (0.2 mg) for the first additional epidural injection of local anesthetic and received continuous injection of buprenorphine (0.2 mg) with 0.25% bupivacaine (40 ml) for twenty-four hours. The last group (Group C ; N = 40) also received bolus injection of buprenorphine as in group B, but received continuous buprenorphine infusion with normal saline instead of local anesthetics. The analgesic effect was determined by the postoperative usage of other analgesics (NSAID or pentazocine) by request of patients. In twenty-four hours, the numbers of patients who did not request other analgesics were 6 (Group A. 16%), 9 (Group B. 33%) and 19 (Group C. 48%), respectively. In Group A, 18 patients requested analgesics, but only 8 patients requested in Group C. It was effective for the postoperative analgesia to use the continuous epidural injection with DIB Catheter for patients after lower extremity arthroplasty. It was necessary to give a bolus injection of buprenorphine before the end of surgery for sufficient analgesia, but it was not necessary to add local anesthetics in the content of DIB Catheter.

Promoter activity of sequence located upstream of the pseudorabies virus early protein 0 gene

Promoter activity of the 5'-flanking region of the pseudorabies virus (PRV) early protein 0 (EP0) gene was analysed by transient transfection assays employing chloramphenicol acetyl transferase (CAT) reporter constructs. We identified a 213 bp segment of the viral genome that was capable of efficiently driving expression of the EPO gene and a linked reporter gene upon transient transfection into Vero cells. This segment lacked the typical TATA element, and possessed an initiator element and the putative binding sites for the transcription factor Sp1 and immediate-early protein IE180, a strong transactivator of PRV. By analysing 5'-deletion mutants of the segment, a 48 bp segment (from nucleotide positions -65 to -17), which possessed three Sp1 binding sites, was identified to be critical for the promoter activity. Cotransfection of Vero cells with the mutant constructs and an IE180 expression plasmid resulted in transactivation of only those constructs in which the Sp1 sites were present. These results indicate that the EP0 gene may be transcribed from the TATA-less promoter that responds to Sp1.

Suppression of pseudorabies virus replication by a mutant form of immediate-early protein IE180 repressing the viral gene transcription

A mutant form of the immediate-early (IE) protein IE180 of pseudorabies virus (PRV), dIN454-C1081 is a strong repressor of the PRV IE gene promoter. In order to assess the antiviral potential of the IE180 mutant, HeLa cells were transformed with the mutant gene and then infected with PRV and herpes simplex virus type 1 (HSV-1). The transformed cell lines showed marked resistance to PRV infection, but were susceptible to infection with HSV-1, indicating that the IE180 mutant expressed in the stable cell line specifically inhibited PRV growth. In those cells infected with PRV, transcription of the PRV IE gene was repressed. In addition, the IE180 mutant exhibited a dominant-negative property in transient expression assay. The present results indicate that the resistance of the cells to PRV infection was due to repression of the IE gene transcription by the IE 180 mutant.

Potentially virulent Newcastle disease viruses are maintained in migratory waterfowl populations

Forty-seven Newcastle disease virus (NDV) strains isolated from fecal samples of waterfowls in Alaska and Siberia from 1991 to 1996 were analyzed for their virulence. None of the viruses formed plaques on MDBK cells in the absence of trypsin. Of these, 29 strains showed virulent character by the mean death time with the minimum lethal dose in chicken embryos comparable to velogenic NDV strains. Of the 29 strains, 11 were sequenced for their fusion protein (F) gene. The results showed that 5 of them contained a pair of dibasic amino acids at the cleavage site of the F, which is of a virulent type. The present results suggest that potentially virulent strains of NDV are maintained in migratory waterfowl populations in nature, and that some of those may be transmitted to domestic poultry and acquire pathogenicity during passages in chicken population.

Fusion of influenza virus with the endosomal membrane is inhibited by monoclonal antibodies to defined epitopes on the hemagglutinin

Epitopes on the hemagglutinin (HA) of A/seal/Massachusetts/1/80 (H7N7) influenza virus were mapped by genetic analysis of variants selected with monoclonal antibodies (MAbs). Electron microscopic studies demonstrated that the sites and the directions to which hemagglutination-inhibiting (HI) MAbs and non-HI MAbs bound were different on the HA molecule. Morphological analysis revealed that HI MAbs blocked attachment of the virus to the cells, while non-HI MAbs did not. Virus particles bound with non-HI MAbs were then found in the intracellular vacuoles. Together with the electron microscopic findings, a fluorescence dequenching assay indicated that non-HI MAbs inhibited the fusion of virus with the intracellular vacuolar membrane. It was thus shown that non-HI neutralizing MAbs did not inhibit attachment of the virus to the host cell receptor, but inhibited the fusion step in intracellular vacuoles. The results support the hypothesis that anti-HA MAbs which lack HI activity neutralize viral infectivity by interfering with the low pH-induced conformational change in the HA molecule, resulting in inhibition of the fusion step in the viral replication process (Kida, H., Yoden, S., Kuwabara, M., Yanagawa, R., 1985. Interference with a conformational change in the HA molecule of influenza virus by antibodies as a possible neutralization mechanism. Vaccine 3, 219-222).

Enzymes responsible for the metabolism of saikosaponins from Eubacterium sp. A-44, a human intestinal anaerobe

From a human intestinal bacterium, Eubacterium sp. A-44, which is capable of hydrolyzing saikosaponins to saikogenins, two glycosidases, beta-D-glucosidase and a novel type of beta-D-fucosidase, were isolated and characterized as saikosaponin-hydrolyzing beta-D-glucosidase and prosaikogenin-hydrolyzing beta-D-fucosidase. Relative to the hydrolyzing activities toward saikosaponins a, b1 and b2, the beta-D-glucosidase showed lower ability to hydrolyze saikosaponin d, but no ability to hydrolyze saikosaponin c or prosaikogenins. By Sephacryl S-300 column chromatography, the molecular weight of prosaikogenin-hydrolyzing beta-D-fucosidase was estimated to be about 130 kDa. The beta-D-fucosidase could hydrolyze prosaikogenins A and F, but not prosaikogenins D and G or saikosaponins. Relative to p-nitrophenyl beta-D-fucoside-hydrolyzing activity, this enzyme had 32.0% and 22.2% of its hydrolyzing ability toward p-nitrophenyl beta-D-glucoside and p-nitrophenyl beta-D-galactoside, respectively. p-Nitrophenyl beta-D-fucoside-hydrolyzing activity was inhibited by D-fucose, and was weakly inhibited by D-glucose, D-glucono delta-lactone, D-galactose and D-galactono delta-lactone. By combining these two glycosidases, saikosaponins a and b1 were converted to their saikogenins via the corresponding prosaikogenins.

Spinal cord compression by heterotopic ossification associated with pseudohypoparathyroidism

This report describes a 37-year-old man presenting with a gait disturbance due to spastic paraparesis. Physical findings showed typical features of Albright's hereditary osteodystrophy, including short stature, obesity, brachydactyly and dental hypoplasia. He was diagnosed as having pseudohypoparathyroidism type Ia, on the basis of his hypocalcaemia, hyperphosphataemia, increased plasma level of parathyroid hormone (PTH), and the unresponsiveness to exogenous PTH loading of his urinary excretion of both nephrogenous cyclic adenosine monophosphate and phosphate. Magnetic resonance imaging and myelographic computed tomographic scans clearly demonstrated severe compression of the spinal cord at T 9/10 by tumour-like ossifications of the paravertebral ligaments. Neurosurgical decompression therapy was, therefore, performed to alleviate his spastic paraparesis. This was a rare case of pseudohypoparathyroidism complicated with spinal cord compression caused by ectopic ossification of the ligaments.

[Ecology of influenza viruses in animals and the mechanism of emergence of new pandemic strains]

Ecological studies on influenza viruses revealed that the hemagglutinin genes are introduced into new pandemic strains from viruses circulating in migratory ducks through domestic ducks and pigs in southern China. Experimental infection of pigs with 38 avian influenza virus strains with H1-H13 hemagglutinins showed that at least one strain of each HA subtype replicated in the upper respiratory tract of pigs. Co-infection of pigs with a swine virus and with an avian virus generated reassortant viruses. The results indicate that avian viruses of any subtype can contribute genes in the generation of reassortants. Virological surveillance revealed that influenza viruses in waterfowl reservoir are perpetuated year-by-year in the frozen lake water while ducks are absent.

[A case of rapidly progressive HTLV-I-associated myelopathy (HAM)]

We report a 65-year-old woman with HAM who showed rapid progression of the clinical symptoms. The initial symptom was lumbago and she became unable to walk within 4 months after the onset of the lumbago. When seen on admission, she had flaccid paraplegia and areflexia was seen in the lower extremities with positive Babinski and Chaddock reflexes. She had numbness below the level of the navel, vibratory sensation was decreased in both lower limbs, and there was a hyperesthesic zone at the tenth thoracic vertebral level. She had a difficulty in urination and defecation. Laboratory examination revealed elevated anti-HTLV-I antibody titers both in serum (4,096x by PA method) and in cerebrospinal fluid (CSF) (4,096x). The levels of IgG and neopterin in CSF were also increased to 16.6 mg/dl (normal: < 5 mg/dl) and 360.3 pmol/ml (normal: < 30 pmol/ml), respectively. HTLV-I messenger RNA positive cells were detected in 0.1% to 0.01% of cells in CSF by in situ hybridization using an oligonucleotide probe labelled with alkaline phosphatase. Spinal cord MRI detected neither spinal cord compression nor vascular diseases. She was treated with 1,000 mg methylprednisolone for 3 days intravenously, followed by 60 mg oral prednisolone therapy. In several days after receiving the treatments, her muscle tonus became spastic and deep tendon reflexes in the legs became brisk. The hyperesthesia at the tenth thoracic vertebral level and numbness below the level of the navel were also gradually improved. Subsequently, her clinical features were consistant with those of the typical HAM. Therefore, the patient was diagnosed as rapidly progressive HAM. The initial phase of rapidly progressive HAM patients had been described only from clinical history. These patients had common characteristic clinical features, such as older age at onset, relatively severe motor dysfunction, high titers of anti-HTLV-I antibody in CSF, and increased levels of neopterin and IgG in CSF, when compared with those of other HAM patients. The clinical course and laboratory findings in the present patient were compatible with those in the previous cases reported as rapidly progressive HAM. This patient showed flaccid paraplegia and areflexia which have rarely been seen in HAM patients. However, these symptoms were changed to spastic and hyperactive after prednisolone therapy. We speculate that inflammation in the spinal cord in this patient was severe enough to spread to the dorsal root, and disturbed the afferent pathway from the peripheral to the central nervous system. This inflammatory reaction might be suppressed by prednisolone to facilitate the recovery of the afferent pathway, which led to the typical clinical symptoms of HAM.

Serotonergic axonal contacts on identified cat trigeminal motoneurons and their correlation with medullary raphe nucleus stimulation

The innervation of the trigeminal motor nucleus by serotonergic fibers with cell bodies in the raphe nuclei pallidus and obscurus suggests that activation of this pathway may alter the excitability of trigeminal motoneurons. Thus, we recorded intracellular responses from cat jaw-closing (JC) andjaw-opening (JO) alpha-motoneurons evoked by raphe stimulation and used a combination of intracellular staining of horseradish peroxidase (HRP) and immunohistochemistry at the light and electron microscopic levels to examine the distribution of contacts made by serotonin (5-HT)-immunoreactive boutons on the two motoneurons types. Electrical stimulation applied to the nucleus raphe pallidus-obscurus complex induced a monosynaptic excitatory postsynaptic potential (EPSP) in JC (masseter) alpha-motoneurons and an EPSP with an action potential in JO (mylohyoid) alpha-motoneurons. The EPSP rise-times (time to peak) and half widths were significantly longer in the JC than in the JO motoneurons. The EPSPs were suppressed by systemic administration of methysergide (2 mg/kg). Six JC and seven JO alpha-motoneurons were well stained with HRP. Contacts were seen between 5-HT-immunoreactive boutons and the motoneurons. The JC motoneurons received a significantly larger number of the contacts than did the JO motoneurons. The contacts were distributed widely in the proximal three-fourths of the dendritic tree of JC motoneurons but were distributed on more proximal dendrites in the JO motoneurons. At the electron microscopic level, synaptic contacts made by 5-HT-immunoreactive boutons on motoneurons were identified. The present study demonstrated that JC motoneurons receive stronger 5-HT innervation, and this correlates with the fact that raphe stimulation caused larger EPSPs among these neurons than among JO motoneurons.

[Effects of methylprednisolone pulse therapy in the insidious type of crescentic glomerulonephritis]

In a attempt to clarify the effects of methylprednisolone pulse therapy on the insidious (subacute) type of crescentic glomerulonephritis with slow, but steady deterioration of renal function and poor response to treatment, we analyzed the clinical course of 24 patients (male:female = 15:9) with a mean age of 48.5 years. They fulfilled the following criteria: 1) crescents were observed in more than 50% of the glomeruli, 2) the increment of serum creatinine (Cr) could be determined sequentially on three or more occasions before treatment, and reciprocals of serum Cr declined with slopes of less than 1.0 x 10(-2) dl/mg/day, 3) corticosteroids and/or immunosuppressants were administered. The patients were divided into two groups: pulse therapy group (P) (15 patients), to which methylprednisolone 500 or 1,000 mg a day was administered intravenously for three consecutive days, and a conventional therapy group (C) (9 patients). There were no differences between groups P and C in clinical parameters, including sex, age, underlying diseases, urinary protein, blood pressure, serum Cr and slope of 1/Cr before treatment, and pathological findings, including percentages of glomeruli with crescents and degree of interstitial lesions. However, improvement of serum Cr, which was defined as a decline to the normal range or less than half of the pretreatment level, was observed in 9 (60%) in group P vs. only 1 (11%) in group C (p < 0.05). Re-biopsies were performed after treatment in 6 patients of group P with an improvement of serum Cr, and showed a decrease in the rate of crescent formation and almost complete loss of cellular crescents. At 1, 2 and 3 years follow-up, the renal survival rates were 86, 70 and 53%, respectively, in group P vs. 67, 14 and 14% respectively, in group C (p < 0.05). No serious side effects were observed in group P. These results suggest that methylprednisolone pulse therapy may be very effective for the insidious type of crescentic glomerulonephritis.

Differences in sialic acid-galactose linkages in the chicken egg amnion and allantois influence human influenza virus receptor specificity and variant selection

Human influenza viruses are more efficiently isolated by inoculating patient samples into the amniotic rather than the allantoic cavity of embryonated chicken eggs. This type of cultivation selects virus variants with mutations around the hemagglutinin (HA) receptor binding site. To understand the molecular basis of these phenomena, we investigated the abundances of sialic acid (SA) linked to galactose (Gal) by the alpha-2,3 linkage (SA alpha2,3Gal) and SA alpha2,6Gal in egg amniotic and allantoic cells and in Madin-Darby canine kidney (MDCK) cells. Using SA-Gal linkage-specific lectins (Maackia amurensis agglutinin specific for SA alpha2,6Gal and Sambucus nigra agglutinin specific for SA alpha2,3Gal), we found SA alpha2,3Gal in both allantoic and amniotic cells and SA alpha2,6Gal in only the amniotic cells. MDCK cells contained both linkages. To investigate how this difference in abundances of SA alpha2,3Gal and SA alpha2,6Gal in allantoic and amniotic cells affects the appearance of host cell variants in eggs, we determined the receptor specificities and HA amino acid sequences of two different patient viruses which were isolated and passaged in the amnion or in the allantois and which were compared with MDCK cell-grown viruses. We found that the viruses maintained high SA alpha2,6Gal specificities when grown in MDCK cells or following up to two amniotic passages; however, further passages in either the amnion or allantois resulted in the acquisition of, or a complete shift to, SA alpha2,3Gal specificity, depending on the virus strain. This change in receptor specificity was accompanied by the appearance of variants in the population with Leu-to-Gln mutations at position 226 in their HA. These findings suggest that lack of SA alpha2,6Gal linkages in the allantois of chicken eggs is a selective pressure for the appearance of host cell variants with altered receptor specificities and amino acid changes at position 226.

Swine influenza virus strains recognize sialylsugar chains containing the molecular species of sialic acid predominantly present in the swine tracheal epithelium

We determined the ratio of N-glycolylneuraminic acid (Neu5Gc) to N-acetylneuraminic acid (Neu5Ac) in swine respiratory epithelia by fluorometric high-performance liquid chromatography, and examined the binding specificity of swine influenza virus strains for gangliosides containing different molecular species of sialic acid (Neu5Ac and Neu5Gc), and for bovine erythrocyte sialoglycoprotein 2 (GP-2) containing Neu5Gc as its predominate sialic acid (96% of total sialic acids). The presence of Neu5Gc, which had not been detected in human tracheal epithelia, and Neu5Ac in swine tracheal epithelia was observed in a 1:1 ratio. The swine influenza virus H1 and H3 isolates tested, except for A/swine/Iowa/15/30 (H1N1), displayed a marked binding ability for sialylsugar chains containing Neu5Gc compared with that of the human influenza virus strains. These results suggest that swine influenza viruses recognize sialylsugar chains containing the molecular species of sialic acid present predominantly in the swine tracheal epithelium.

Receptor specificity of influenza A viruses correlates with the agglutination of erythrocytes from different animal species

Despite their uniform ability to bind to oligosaccharide-containing terminal sialic acids, influenza A viruses show differences in receptor specificity. To test whether agglutination of erythrocytes from different animal species could be used to assess the receptor specificity of influenza A viruses, we determined the agglutinating activities of a range of virus strains, including those with known receptor specificities, using erythrocytes from seven animal species. All equine and avian viruses, including those known to recognize N-acetyl and N-glycolyl sialic acid linked to galactose by the alpha2,3 linkage (NeuAc alpha2,3Gal and NeuGc alpha2,3Gal), agglutinated erythrocytes from all of the animal species tested (chickens, ducks, guinea pigs, humans, sheep, horses, and cows). The human viruses, including those known to preferentially recognize NeuAc alpha2,6Gal, agglutinated all but the horse and cow erythrocytes. Fluorescence-activated cell sorting analysis of erythrocytes using linkage-specific lectins [Sambucus nigra agglutinin for sialic acid (SA) alpha2,6Gal and Maackia amurensis agglutinin for SA alpha2,3Gal] showed that both cow and horse erythrocytes contain a large amount of SA alpha2,3Gal-, but virtually no SA2,6Gal-specific lectin-reactive oligosaccharides on the cell surface, while human and chicken erythrocytes contained both types of oligosaccharides. Considering that the majority (>93%) of sialic acid in horse and cow erythrocytes is of the N-glycolyl type, our results suggest that viruses able to agglutinate these erythrocytes (i.e., avian and equine viruses) recognize NeuGc alpha2,3Gal. These findings also show that agglutinating assays with erythrocytes from different animal species would be useful in characterizing the receptor specificity of influenza A viruses.

The change in tenascin expression in mouse uterus during early pregnancy

PURPOSE

Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring.

METHODS

Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through Day 5 were analyzed.

RESULTS

Immunoreactive TN and TN mRNA were expressed in the basement membrane of the epithelium as well as in the smooth muscle layer, and their distribution shifted from the subbasement region on Day 0-3 to the smooth muscle layer on Days 4 and 5.

CONCLUSIONS

These results indicate that TN expression in the uterus during early pregnancy is spatiotemporally different and may be regulated by a different mechanism.