Evaluation of antioxidant activity by chemiluminescence

A sensitive and simple chemiluminescent method for measuring antioxidant activity was developed. The method is based on antioxidant-dependent quenching of chemiluminescence generated from lipid hydroperoxide and isoluminol/microperoxidase reagent. This method was used to evaluate the antioxidant ability of various antioxidants by measuring the half-inhibition concentration (IC50). The results were compared to those measured with an oxygen electrode method. They were approximately similar in pattern and level, although there was some discrepancy, which was assumed to be due to a possible difference in the reaction mechanisms of the two methods. This method also suggested an additive property of antioxidant activity with different antioxidants. Thus, the present method was used to evaluate the total antioxidant activity in biological tissues such as rat serum, human saliva, and green tea.

Functional roles of protein domains on rice alpha-amylase activity

Characteristics of two rice alpha-amylases Amy1A and Amy3D, and those of two chimeric enzymes Amy1A/3D and Amy3D/1A, engineered from the two isozymes, were compared in the light of the functional roles of protein domains in alpha-amylase. The enzymes that have an Amy1A-type N-terminal domain, Amy1A and Amy1A/3D, showed high activity against soluble starch, while the enzymes that have an Amy3D-type barrel structure, Amy3D and Amy1A/3D, showed high activity in oligosaccharide hydrolysis. Rigidity of protein folding also significantly affected the enzyme activity in both soluble starch and oligosaccharide hydrolysis. Thus, the present work suggests that the structure of the N-terminal domain is important for stability and soluble starch hydrolysis, while the barrel structure that forms the active site significantly affects enzyme activities in oligosaccharide degradation. We have already characterized two rice alpha-amylase isozymes, Amy1A and Amy3D, and a chimeric enzyme engineered from these two isozymes, Amy1A/3D (Terashima et al. 1995, 1996a,b). In spite of the high homology (70%) of their amino acid sequences, Amy1A and Amy3D showed distinct differences in their enzymatic characteristics. The chimeric enzyme Amy1A/3D, which consists of an Amy1A-type N-terminal domain and an Amy3D-type barrel structure, inherited enzymatic characteristics from the both isozymes. In this work, one other chimeric enzyme, Amy3D/1A, which is the counterpart of Amy1A/3D, has been characterized. The characteristics of these four enzymes are discussed in the light of the functional roles of protein domains.

Possible implication of leukocytes in secondary pathological changes after spinal cord injury

We reviewed 95 consecutive patients with cervical spinal cord injury admitted within 2 days of injury and treated nonoperatively, to elucidate the relationship between neurological deterioration and the white blood cell count in the first 4 days after injury. The count for 14 patients who had neurological deterioration was 13.2 +/- 3.2 x 10(9)/l, and that for 81 patients who had no deterioration was 11.0 +/- 3.1 x 10(9)/l. None of 19 patients whose highest white blood cell count was less than 9 x 10(9)l deteriorated, while 14 of 76 patients whose count was 9 x 10(9)/l or more deteriorated. These results suggest that the white blood cell is important in the secondary pathological changes after mechanical injury to the spinal cord.

Isolation, properties and a possible function of a water-soluble chlorophyll a/b-protein from brussels sprouts

A water-soluble Chl a/b-protein (CP673) was isolated and purified from Brussels sprouts (Brassica oleracea L. var. gemmifera DC). The protein had a molecular mass of 78 kDa and an isoelectric point of 4.7, consisted of three or four subunits of 22 kDa and was extremely heat-stable. Although CP673 contained about one Chl a per protein, the blue and red absorption bands of Chl a that consisted of three or four Chl a forms with different absorption maxima suggested that there are several different modes or sites of binding for Chl a. Chl a/b ratio of larger than 10 also indicated that Chl b is present only in a small fraction of CP673. The heterogeneity of CP673 in terms of composition and binding of Chl suggests that Chl is not an intrinsic component of the Chl-protein. Homology search showed that the N-terminal amino acid sequence of CP673 is highly homologous with that of a 22 kDa protein that accumulates in water-stressed leaves of two Brassicaceae plants, rapeseed and radish, but not with those of the light-harvesting Chl a/b-proteins of photosynthesis. A possible function of the water-soluble Chl-protein was discussed.

[Angle of defect on 123I-MIBG myocardial SPECT]

The quantitative assessment of infero-posterior defect on 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was studied in 150 patients with non-ischemic heart diseases at rest. The bull's eye map, obtained from the SPECT images at 4 hours after MIBG injection, was evaluated by generating the blacked out map which exhibits regions with reduced % uptake under mean-2 SD of 13 normal controls. The blacked out regions involved infero-posterior segments and were closely resembled to the sector form. The central angle of this sector, which was named as angle of defect (AOD), significantly correlated with both the heart-to-mediastinum activity ratio (H/M) and the myocardial clearance of MIBG. Because H/M and clearance are widely used as quantitative indices in MIBG myocardial scintigraphy, these results indicate that AOD can also be used as a quantitative index of abnormal cardiac sympathetic nervous function, which is likely to appear in infero-posterior regions in non-ischemic cardiac diseases.

Nerve growth factor rescues PC12 cells from apoptosis by increasing amount of bcl-2

Nerve growth factor (NGF) suppressed the decrease in number of viable PC12 cells after serum withdrawal from culture medium. Accordingly, the amount of bcl-2, a suppressive effector of apoptosis, increased in these cells. Bcl-2 antisense oligonucleotide suppressed not only the NGF-induced increase in bcl-2 but also NGF-induced neuronal differentiation. Results of fluorescent DNA staining indicated that NGF inhibited the chromatin condensation of PC12 cells resulting from serum withdrawal and further that the bcl-2 antisense oligonucleotide canceled this effect of NGF. The present results suggest that NGF rescues PC12 cells from apoptosis induced by serum withdrawal via up-regulation of bcl-2.

[Nephrotic syndrome related to chronic graft versus host disease after allogeneic bone marrow transplantation in a patient with malignant lymphoma]

A 13-yr-old boy was diagnosed as T cell lymphoma. After the second remission, he underwent BMT from an HLA-identical, MLC negative sibling donor. After BMT, he developed grade II acute GVHD. GVHD was improved by pulsed steroid therapy using prednisolone. About 12 months after BMT, he developed bronchiolitis obliterans, sicca syndrome, and leukoderma, which were related to chronic GVHD. Pulsed steroid therapy was carried out twice, and his condition improved. Twenty-seven months after BMT, he developed nephrotic syndrome. A renal biopsy was performed, and the diagnosis was histologically membranous nephropathy and focal glomerular sclerosis. The response to steroids was not satisfactory. After 5 weeks, dipyridamole was added, but proteinuria persisted. Proteinuria disappeared 8 weeks after the addition of cyclosporine. The second biopsy after 5 months of treatment revealed an improvement in the renal lesions. The patient showed a low T4 to T8 ratio of T-lymphocytes at the onset of nephrotic syndrome. However after treatment with cyclosporine, the ratio gradually increased. These findings suggested the nephrotic syndrome in this patient was related to renal involvement in the course of chronic GVHD.

Tetrahydrobiopterin biosynthesis enhanced by lipopolysaccharide stimulation in murine neuroblastoma cell line N1E-115

We investigated for the first time the effect of lipopolysaccharide and the signal transduction pathway on the biosynthesis of tetrahydrobiopterin [(6R-L-erythro-1',2'-dihydroxypropyl) -2-amino-4-hydroxy-5,6,7,8-tetrahydropteridine], the cofactor for the enzymatic hydroxylation of the aromatic amino acids, in the murine neuroblastoma cell line N1E-115, which synthesizes tetrahydrobiopterin constitutively. Activation of N1E-115 cells with 1 microgram/ml lipopolysaccharide resulted in statistically significant increases in both intracellular tetrahydrobiopterin contents and the activity (Vmax) of GTP cyclohydrolase I, a rate-limiting enzyme in tetrahydrobiopterin de novo biosynthesis. Following simultaneous addition of the inhibitors of protein tyrosine kinases and GTP-binding proteins into serum-free culture media with lipopolysaccharide, we analyzed the transduction pathway of lipopolysaccharide signal toward the tetrahydrobiopterin biosynthetic system in N1E-115 cells. Our data indicate the following conclusions: (a) Protein tyrosine kinase systems are involved in mediating lipopoly-saccharide signal to tetrahydrobiopterin production, and (b) there may be a cross-talk between GTP-binding protein and the protein tyrosine kinase system in mediating lipopolysaccharide signal. These observations suggest that a neuronal cell such as N1E-115, which barely expresses CD14 on its cell surface, responds to lipopolysaccharide like macrophages and monocytes in the absence of soluble CD14.

Sphenoethmoidal mucoceles with intracranial extension--three case reports

Three unusual cases of sphenoethmoidal mucoceles with rare intracranial extension are reported. A 64-year-old female presented with a 7-month history of right visual disturbance. Computed tomography (CT) and magnetic resonance (MR) imaging demonstrated a huge mass in the right middle fossa. She underwent right frontotemporal craniotomy. Postoperatively, her proptosis and cranial nerve dysfunction had improved markedly. A 53-year-old female complained of headache, nausea, and dizziness. CT and MR imaging revealed a cystic mass filling the right sphenoid sinus. The cystic lesion was evacuated through the transnasal approach. She was doing well postoperatively and has been asymptomatic. A 39-year-old male complained of headache, vomiting, and right visual disturbance. CT and MR imaging demonstrated a homogeneous mass occupying the sphenoid sinus. Sphenoidotomy exposed the cyst extending superiorly into the anterior cranial fossa. He recovered from the visual disturbances and has been asymptomatic since. MR imaging provides confirmation of the diagnosis of sphenoethmoidal mucocele and is important for preoperative evaluation.

Secondary structure and thermostability of the photosystem II manganese-stabilizing protein of the thermophilic cyanobacterium Synechococcus elongatus

The secondary structure of the manganese-stabilizing protein of the thermophilic cyanobacterium Synechococcus elongatus in solution was investigated by Fourier-transform infrared (FT-IR) and circular dichroism (CD) spectroscopies. Both methods showed a high proportion of disordered structure (40-43%) and a relatively small amount of beta-sheet (23-24%) and alpha-helix (17-19%). The conformation of the protein remained essentially unchanged at temperatures up to 70 degrees C. Unfolding of the protein occurred at higher temperatures and FT-IR spectroscopy revealed that beta-sheet was more strongly unfolded than alpha-helix at 76 degrees C. The protein largely lost the ordered secondary structures at 90 degrees C, but, when cooled down to 30 degrees C, regained its original conformation. Thus, the cyanobacterial protein is very thermostable and its denaturation at an extremely high temperature is reversible.

Neurologic outcome in conservatively treated patients with incomplete closed traumatic cervical spinal cord injuries

STUDY DESIGN

The neurologic outcomes in patients with conservatively managed incomplete closed traumatic cervical spinal cord injuries was evaluated using the motor scoring system and the Frankel classification.

OBJECTIVES

To show that the motor scoring of recovery system combined with functional Frankel grading will make the documentation of final neurologic outcome more accurate for future comparisons of various methods of treatment.

SUMMARY OF BACKGROUND DATA

The influence of surgical and pharmacologic methods of treatment on recovery remains debatable.

METHODS

Sixty-three consecutive patients with incomplete cervical injuries who were admitted to the hospital within 2 days after injury were included. All patients were treated conservatively with 6 weeks of bedrest and 6 weeks of mobilization with neck support.

RESULTS

Five patients had neurologic deterioration, and all but one patient recovered without surgery. The evaluation of 44 patients who were observed for more than 12 months showed that the preservation of sharp sensation below the level of injury was an indicator of a good prognosis in patients whose injuries were classified as Frankel B, and the degree of recovery of these patients according to the motor score system was comparable with that of patients who were classified as Frankel C. All patients classified as Frankel C who did not deteriorate recovered in Frankel grade. All but one of the patients in the Frankel D group recovered full motor power. The degrees of motor deficit and recovery did not correlate with the mechanism or the degree of the injury of the spinal axis.

CONCLUSION

Conservative treatment remains a good option for patients with incomplete cervical cord injuries. It is hoped the current study will be a good basis for comparison of the neurologic outcomes of different treatment modalities.

Effects of lecithinized superoxide dismutase on rat spinal cord injury

Although superoxide dismutase (SOD) has been reported to promote functional recovery in ischemic spinal cord injury, it presents many difficulties in practical use primarily due to its short half-life in vivo and low tissue affinity. In this study, we investigated the effects of a new type of SOD, a lecithinized superoxide dismutase (PC-SOD), on motor disturbances, spinal cord edema, levels of myeloperoxidase (MPO), and spinal cord blood flow (SCBF) after spinal cord injury (SCI) in rats. PC-SOD is reported to show a delayed plasma disappearance in vivo in rats and has a higher affinity for vascular endothelium cells, neutrophils, and other cells than unmodified SOD. PC-SOD (4000 units/kg), unmodified SOD (4000 units/kg), or vehicle was injected intravenously 30 min after SCI. Four hours after SCI, SOD activities in spinal cord tissue and plasma were significantly higher in the PC-SOD group than in the unmodified SOD group. In the PC-SOD-treated rats, motor function was significantly better than in the other 2 groups of rats. PC-SOD significantly suppressed MPO activity, an indicator of neutrophils infiltration, in the spinal cord, at 4, 8, and 24 h after SCI, and spinal cord edema at 24 h after SCI. Moreover, the decrease of SCBF after SCI was less marked in the PC-SOD group. The present results suggest that lecithinization can improve the drug delivery of SOD to the spinal cord and PC-SOD may be an alternative pharmacological treatment for SCI.

Induction and its spread of apoptosis in rat spinal cord after mechanical trauma

This study was undertaken to examine the spinal cord of rats after trauma for the induction of apoptosis. DNA ladder formation was demonstrated by gel electrophoresis of the DNA obtained from the spinal cord at the site of injury after trauma from 12 h to 8 days and was most significant on Days 3 and 4. As for the longitudinal spread of the injury in the spinal cord, the ladder formation was observed in the two segments adjacent to the site of trauma 3 days after trauma. Histological examination using in situ end labeling also demonstrated the appearance of apoptosis. These results provide the evidence for the induction of apoptosis in the spinal cord after trauma in rats.

Growth of the cervical spine with special reference to its lordosis and mobility

STUDY DESIGN

The cervical spine of the healthy Japanese children aged between 1 year and 18 years was radiographically examined.

OBJECTIVES

To examine the correlation between growth of the cervical vertebral body and the facet joint and the development of the cervical lordosis and intervertebral motion.

SUMMARY OF BACKGROUND DATA

Although the growth of body height and facet angle have been well documented, their correlation with curvature or mobility has not been elucidated.

METHODS

We evaluated plain lateral radiographs of 180 boys and 180 girls regarding diameters and central heights of the cervical vertebra, the anterior and posterior vertebral height ratio, body height index, the facet joint angles, and tilting and sliding motions. Cervical length as the summation of the central height from C3 to C7 and the cervical lordosis angle (C3-C7 angle) were also measured.

RESULTS

The mean C3-C7 angle and body height index gradually decreased until 9 years of age and then increased. The C3-C7 angle showed a significant correlation with cervical length, body height index, and facet joint angles before 9 years of age, and with cervical length and body height index after 9 years of age but not with facet joint angles. Facet joint angle decreased until 10 years of age and remained almost unchanged thereafter. Total sliding showed a significant age-related decrease and showed a significant correlation with facet joint angle.

CONCLUSION

Although the lordosis angle showed a significant correlation with the other values, cervical length, body height index, and facet joint angle, the determinants of the lordosis could not be elucidate in the present study. As for the mobility of the cervical spine, changes of tilting motion were small, whereas changes of sliding motion were restricted by the change of orientation of the facet joints.

Synthesis and selective coronary vasodilatory activity of 3,4-dihydro-2,2-bis(methoxymethyl)-2H-1-benzopyran-3-ol derivatives: novel potassium channel openers

A variety of compounds having a benzopyran such as levcromakalim generally exhibit potent antihypertensive activity. During extensive investigations aimed toward identifying K+ channel openers having selective coronary vasodilation without potent hypotensive and tachycardiac effects, we synthesized a series of 3,4-dihydro-2H-1-benzopyran-3-ol derivatives modified at positions 2, 4, and 6 in the benzopyran ring. Initially, compounds having two methoxymethyl groups at position 2 were found to show a selective effect on coronary blood flow (CoBF) relative to mean arterial pressure (MAP) in anesthetized dogs. To find more potent vasodilators, various benzopyran derivatives modified at position 4 were synthesized and structure-activity relationships were examined by evaluation of the extent and duration of the increase in CoBF in anesthetized dogs. As a result, compounds having a (1,6-dihydro-6-oxopyridazin-3-yl)amino group at position 4, in addition to the two methoxymethyl groups at position 2, were found to be more potent and to have an improved duration of action. Among these compounds, JTV-506, (-)-(3S,4R)-6-cyano-3,4-dihydro-4-[(1,6-dihydro-1-methyl-6-oxopyridaz in-3-yl)amino]-2,2-bis(methoxymethyl)-2H-1-benzopyran-3-ol, exhibited good selectivity for its effect. Administration of this compound (0.03 mg/kg, p.o.) elicited an increase of CoBF without a change of systemic blood pressure and heart rate (HR) in conscious dogs. Further evaluation was performed with respect to (i) the selectivity of its action on the coronary artery versus the aorta and (ii) its effects on MAP, HR, and electrocardiographic ST elevation. As a result, JTV-506 was selected as a potent and selective coronary vasodilator with various pharmacological features favoring clinical development.

Structure of the human cytomegalovirus protease catalytic domain reveals a novel serine protease fold and catalytic triad

Proteolytic processing of capsid assembly protein precursors by herpesvirus proteases is essential for virion maturation. A 2.5 A crystal structure of the human cytomegalovirus protease catalytic domain has been determined by X-ray diffraction. The structure defines a new class of serine protease with respect to global-fold topology and has a catalytic triad consisting of Ser-132, His-63, and His-157 in contrast with the Ser-His-Asp triads found in other serine proteases. However, catalytic machinery for activating the serine nucleophile and stabilizing a tetrahedral transition state is oriented similarly to that for members of the trypsin-like and subtilisin-like serine protease families. Formation of the active dimer is mediated primarily by burying a helix of one protomer into a deep cleft in the protein surface of the other.

Spinal deformity following surgery for spinal cord tumors and tumorous lesions: analysis based on an assessment of the spinal functional curve

The mechanism of spinal deformity after surgical removal of a cervical spinal cord tumor or tumorous lesions was studied in 36 patients, based on the spinal functional curve prepared from the intersectional angle. The postoperative spinal deformity depends on the surgical level and the type of operation. In the laminectomy group, kyphosis of the upper cervical spine and compensatory increased lordosis of the lower cervical spine were observed in the C2 laminectomy patients. Localized kyphosis of the spine at the cervicothoracic junction and compensatory increased lordosis of the upper cervical vertebrae were noted in the C7 laminectomy patients. In the laminoplasty group, spinal deformities were less frequently observed, and when present the deformity was limited to a slight increase of lordosis, even in patients who had the facetectomy. These facts demonstrate the preventive effect of the laminoplasty regarding postoperative spinal deformity. Laminoplasty with reconstruction of the erector spinal muscles and the nuchal ligament is recommended for patients with a spinal cord tumor or a tumorous lesion. The spinal functional curve was significant in studying the biomechanics of the vertebral column with the advantage that both alignment and mobility of the spine are simultaneously, respectively and precisely visualized.

Surgical modulation of the natural course of collateral circulation in chronic ischemic patients

The purpose of this study was to evaluate hemodynamic compromise in terms of baseline CBF and CRC in patients with chronic cerebral occlusive lesions and its modulation by a superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. The study subjects were 10 healthy volunteers and 49 chronic ischemic patients with stenosis or occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA). The hemodynamics were measured using stable xenon enhanced computed tomographic CBF measurement with the acetazolamide challenge. The compromised hemodynamics in patients with chronic steno-occlusive lesions did not improve during their natural course after two months. STA-MCA bypass modulated hemodynamic compromise in the ischemic patients. We recommend STA-MCA bypass for patients with reduced CRC, regardless of whether baseline CBF is reduced or normal. Hemodynamic classification using a combination of baseline CBF values and CRC values is useful for evaluating cerebral hemodynamics and for choosing the best treatment for cerebral ischemia with occlusive lesions.

Sports-related spinal cord injury in Japan (from the nationwide spinal cord injury registry between 1990 and 1992)

The Injury Prevention Committee of the Japan Medical Society of Paraplegia (JMSoP) conducted a nationwide epidemiological survey on spinal cord injury (SCI) using postal questionnaires for 3 years periods from 1990 to 1992, and the annual incidence of the spinal cord injury was estimated as 40.2 per million. From this registry, we investigated SCI related to sports activities. In 3 years, 528 patients were registered and 374 of them had neurological deficits. The incidence was 1.95 per million per annum. Mean age at injury was 28.5 years (10-77), and 88.1% of the patients were males. Diving was the commonest cause of SCI (21.6%), which was followed by skiing (13.4%), football including rugby, American football and soccer (12.7%), sky sports (7.0%), judo (6.8%) and gymnastics (6.6%). Mean age at injury was higher than 30 years in skiing (38.6 years) and sky sports (38.2 years). Cervical injury was predominant in all but sky sports and accounted for 83.5% of SCI. Motor complete paralysis was reported in 35.0% of the patients. Bony injury was observed in 55.9% of the patients; most of the patients who sustained the SCI in diving and sky sports had bony injury, and no bony injury was detected in more than a half of the patients who sustained injuries in skiing, judo or gymnastics. Although the percentage of sports-related SCI was small in the present study as compared to the data from previous reports, it is not difficult to imagine the increase in the number of sports-related SCI. We have launched an injury prevention campaign and are planning to conduct a similar study in future to evaluate the effect of the campaign as well as the changes in the incidence and pattern of SCI.

Investigation of the relationship between regression of hypertensive cardiac hypertrophy and improvement of cardiac sympathetic nervous dysfunction using iodine-123 metaiodobenzylguanidine myocardial imaging

Although many theories exist on the subject, the mechanisms responsible for a reduction of hypertensive cardiac hypertrophy in response to antihypertensive therapy are still unclear. In order to investigate the relationship between regression of hypertensive cardiac hypertrophy and cardiac nervous function, we studied ten patients with untreated essential hypertension (six men and four women, 62+/-12 years old). Both echocardiography and iodine-123 metaiodobenzylguanidine (MIBG) myocardial imaging were performed before and after antihypertensive therapy. Left ventricular mass (LVM) was significantly reduced in conjunction with the reduction of blood pressure following treatment. MIBG myocardial images showed that the heart-to-mediastinum activity ratio (H/M) was significantly increased while the washout ratio was significantly decreased. Patients were divided into two groups according to the ratio of the LVM values before and after therapy (LVM ratio). Patients with an LVM ratio of less than 0.75 were classified as group A and those with values higher than 0.75 as group B. Neither the change in blood pressure nor the length of treatment was significantly different between these two groups. On the other hand, both the increase in H/M and the decrease in the washout ratio were significantly greater in group A than in group B. These results indicate that an improvement in cardiac sympathetic nervous function may be related to the regression of hypertensive cardiac hypertrophy. Increasing the subject base in these studies and a more precise analysis of the relevance of the data obtained from MIBG myocardial images are recommended to clarify how changes in cardiac sympathetic nervous function relate to the regression of hypertensive cardiac hypertrophy.

Role of cytokines in leukemic type growth of myelodysplastic CD34+ cells

The clonal growth of progenitor cells from myelodysplastic syndromes (MDS) can be subdivided into four growth patterns: (1) normal, (2) no growth or low plating efficiency, (3) low colony and high cluster number, and (4) normal or high colony number with a large number of clusters. The former two (1 and 2) can be referred to as nonleukemic patterns and latter two (3 and 4) as leukemic. In a search for a role for cytokines in leukemic-type growth of MDS progenitor cells, marrow CD34+ cells were purified up to 94% for 8 normal individuals and 88% for 12 MDS patients, using monoclonal antibodies and immunomagnetic microspheres (MDS CD34+ cells). The purified CD34+ cells were cultured for 14 days with various combinations of cytokines, including recombinant human macrophage colony-stimulating factor (rM-CSF), granulocyte-CSF (rG-CSF), granulocyte-macrophage-CSF (rGM-CSF), interleukin-3 (rIL-3), and stem cell factor (SCF; a ligand for c-kit) in serum-free medium. The clonal growth of MDS CD34+ cells supported by a combination of all of the above cytokines was subdivided into the two patterns of leukemic or nonleukemic, and then the role of individual or combined cytokines in proliferation and differentiation of MDS CD34+ cells was analyzed in each group. Evidence we obtained showed that SCF plays a central role in the leukemic-type growth of MDS CD34+ cells and that G-CSF, GM-CSF; and/or IL-3 synergize with SCF to increase undifferentiated blast cell colonies and clusters over that seen in normal CD34+ cells. SCF is present in either normal or MDS plasma at a level of nanograms per milliliter, and this physiologic concentration of SCF can stimulate progenitor cells. This means that progenitor cells are continuously exposed to stimulation by SCF in vivo and that MDS leukemic cells have a growth advantage over normal blast cells. This depends, at least in part, on cytokines such as G-CSF, GM-CSF, IL-3, and SCF.

Regression of moyamoya vessels and hemodynamic changes after successful revascularization in childhood moyamoya disease

Successful revascularization improves ischemic symptoms in the pediatric patients with moyamoya disease. However, it is not clear whether the revascularization prevents future intracranial hemorrhage from the residual moyamoya vessels. The purpose of this study is to investigate perioperative morphological and hemodynamic changes in the moyamoya vessels. Four pediatric patients (age < 15 years old) with bilateral moyamoya disease were selected for this study. To quantify the number of moyamoya vessels, T1-weighted transverse images at the level of the basal ganglia and the thalamus were selected and characteristic flow voids in the lentiform nucleus were counted. Resting CBF and cerebrovascular reserve capacity (CRC) were measured pre- and 1 year after surgery using Xenon-CT CBF method with acetazolamide test. The ratio of deep CBF/cortical CBF was calculated as an index of hemodynamic stress distribution. The one-year follow-up studies showed that 1) the number of moyamoya vessels decreased on the operative side, but did not change on the non-operative sides in all cases; 2) the ratio of deep CBF/cortical CBF decreased on the operative sides, but did not change in the non-operative sides; and 3) the CRC increased on both sides. This observation suggests the possibility that revascularization surgery may be effective for preventing the future risk intracranial hemorrhage.

Use of peptide immunization for porcine insulin of a very high homology with a host protein

An anti-peptide antibody was obtained against a peptide corresponding to the 12 amino acids of the C-terminal region of porcine insulin B chain. The adsorption characteristics of this antibody were compared with those of anti-porcine insulin and anti-sheep insulin antibodies. Immunization of rabbits using the peptide corresponding to the C-terminal region of porcine insulin B chain produced an anti-peptide antibody which reacted with native porcine insulin with a much higher association constant than that of an anti-porcine insulin antibody. In addition, this immunization technique did not cause any observable physiologically harmful effects, such as hypoglycemia, in the immunized rabbits. Thus, peptide immunization may be a useful strategy when target proteins have biological activity and/or toxicity, and also have a very high degree of homology with the corresponding proteins of the immunized animal, which may inhibit the production of antibodies with a high association constant.

Morphologic analysis of the facet joint in the immature lumbosacral spine with special reference to spondylolysis

STUDY DESIGN

Morphological analysis was performed of the facet joint of the normal and spondylolytic lumbosacral spine in children and adolescents.

OBJECTIVES

This study was performed to estimate the influence of spondylolysis on growth of the neural arch of the lumbosacral spine.

SUMMARY OF BACKGROUND DATA

The development of the facet joint and its relation to spondylolysis have not been documented in the literature.

METHODS

The dimension and orientation of the facet joint at L5/S were measured on radiographs and computed tomography scans from 144 boys without pars defects and 104 boys with pars defects. The latter group was further investigated according to the stage of pars defects. Patients in both groups were between 9 and 18 years of age.

RESULTS

Growth of the facet joint in the sagittal and transverse directions and the increase of the transverse angle were remarkable up to approximately 13 years of age. Concavity of the facet joints also progressed in children of the same age. The growth of the facet joint in patients with spondylolysis was significantly retarded as the pars defects advanced from the progressive to the terminal stage. The joint surface was more coronal in orientation and flatter in shape compared with controls.

CONCLUSIONS

The present results suggest that pars defects occurring in children disturb or retard the growth of the facet joint and that the morphological characteristics of the joint surfaces in patients with spondylolysis are the consequence of these defects.

Effect of dietary vitamin C on compression injury of the spinal cord in a rat mutant unable to synthesize ascorbic acid and its correlation with that of vitamin E

The roles of vitamin C on secondary pathological changes after spinal cord injury were investigated by evaluating the effects of dietary vitamin C on experimental spinal cord injury in a mutant strain of Wistar rats unable to synthesize ascorbic acid (ODS rats). Two groups of ODS rats were given vitamin C-deficient or vitamin C-supplemented diet for 1 week before injury. Motor disturbance induced by spinal cord injury was found to be greater in the vitamin C-deficient group. Histologically, the area of bleeding in the spinal cord was also greater in the vitamin C-deficient group. The levels of ascorbic acid and alpha-tocopherol in the spinal cord tissue and serum decreased during and after compression injury of the spinal cord. The decrease of alpha-tocopherol was similar in the two groups. However, the decrease of ascorbic acid was greater in the vitamin C-supplemented group. These results indicated that their protective effects against spinal cord injury are through scavenging water-soluble free radicals by vitamin C and lipid-soluble by vitamin E, and the effects of these vitamins were suggested to be independent.

Involvement of an intercellular adhesion molecule 1-dependent pathway in the pathogenesis of secondary changes after spinal cord injury in rats

The intercellular adhesion molecule 1 (ICAM-1) plays an important role in immune responses by promoting infiltration of neutrophils into tissues; however, its implication in the secondary destructive pathomechanism after the initial mechanical injury to the spinal cord has not been clarified yet. This study was conducted to examine the role of ICAM-1 in this process after spinal cord injury (SCI) in rats. The expression of ICAM-1 mRNA was investigated by the reverse transcription-PCR method and the effect of monoclonal antibody (mAb) to ICAM-1 on SCI was evaluated by measuring various parameters. ICAM-1 mRNA expression correlated with the severity of injury and reached its maximum level 6 h after SCI. Intravenous injection of ICAM-1 mAb (1 mg/kg) 30 min after SCI reduced motor disturbance and enhanced recovery. Moreover, it significantly suppressed myeloperoxidase activity by 43.0% and spinal cord edema by 1.1% in the injured spinal cord tissue. The posttraumatic drop in spinal cord blood flow was also improved. These results suggest that ICAM-1 is deeply involved in the secondary self-destructive process after mechanical injury of the spinal cord and should be an effective target for developing a pharmacological treatment for SCI.

Inhibition of protein serine/threonine phosphatases by fumonisin B1, a mycotoxin

Fumonisin B1 (FB1), a mycotoxin produced by the fungus Fusarium moniliforme, which is a common contaminant of corn, is suspected to be a cause of human esophageal cancer. FB1 is hepatotoxic and hepatocarcinogenic in rats, and although the mechanisms involved have not been clarified, the latter is associated with a weak initiating activity. The effects of FB1 on the activity of protein serine/threonine phosphatases (PPs) (PP1, PP2A, PP2B, PP2C and PP5/T/K/H) were investigated in the present study. Inhibition of dephosphorylation was noted for all five PPs with IC50 values of 80 microM-3000 microM. Among the five PPs examined, PP5 was most sensitive with an IC50 of 80 microM. This concentration is comparable to that estimated to be reached in the rat body by feeding FB1 to obtain hepatic tumors. Inhibition of PP5 could thus play important roles in the toxicity and carcinogenic action of FB1.

Validation of the American Spinal Injury Association (ASIA) motor score and the National Acute Spinal Cord Injury Study (NASCIS) motor score

STUDY DESIGN

In this study the motor scores of 62 consecutive acute spinal cord-injured patients were retrospectively reviewed.

OBJECTIVE

The reliability of the American Spinal Injury Association and National Acute Spinal Cord Injury Study motor scores, compared with the conventional motor scores, was retrospectively assessed.

SUMMARY OF BACKGROUND DATA

The reliability of the American Spinal Injury Association and National Acute Spinal Cord Injury Study scores has not as yet been confirmed.

METHODS

Sixty-two consecutive adult patients admitted within 7 days of acute spinal cord injury between April, 1983, and September, 1992, were evaluated. The motor deficit percentage and the motor recovery percentage of each of the American Spinal Injury Association and the National Acute Spinal Cord Injury Study motor scores were compared with those of the conventional motor score. From the initial and final motor score, the motor deficit percentage and motor recovery percentage were calculated. There were 38 patients with cervical and thoracic lesions, 12 patients with dorso-lumbar lesions, and 12 patients with lower lumbar lesions. The average follow-up period was 41 months.

RESULTS

Both the American Spinal Injury Association motor score and the National Acute Spinal Cord Injury Study motor score were representative of the conventional motor score for the evaluation of the motor deficit percentage and the motor recovery percentage in all levels (P < 0.0001). The differences in all correlation coefficients between the American Spinal Injury Association motor score and the National Acute Spinal Cord Injury Study motor score were not statistically significant in all levels and in every group.

CONCLUSIONS

The American Spinal Injury Association and National Acute Spinal Cord Injury Study motor scores can both be used for the neurological quantification of motor deficit and motor recovery.

[Prevention of MRSA spread in the neurosurgical field]

We investigated the distribution of MRSA (methicillin-resistant Staphylococcus aureus) on and around six patients with MRSA infection in our neurosurgical ward. All patients had a disturbance of consciousness and had sputum colonization of MRSA. Samples were obtained from 11 sites (patients' hands, attendances' hands, floors, sidetables, bedclothes, chairs, walls, curtains, door knobs, faucets and disposable gloves) in the patients' rooms by the wiping method. High counts of MRSA were detected on horizontal planes such as floors, sidetables and chairs, but MRSA was not detected on vertical planes such as curtains and walls. The reason why MRSA was detected on the horizontal planes was due to a fall of MRSA spread from sputum in the air. These findings indicate that the disinfection of horizontal planes is important for preventing the spread of MRSA. We also evaluated what disinfectant was useful for floor disinfection and concluded that 0.5% chlorhexidine digluconate (Hibitane) and 0.5% benzalkonium chloride (Osvan) were more effective than the other usually-used disinfectants such as alkyldiaminoethyl glycine (Tego-51).

Yellow marking and pteridine contents in the integument of albino Armadillidium vulgare

The albino mutant strain in the woodlice, Armadillidium vulgare, was investigated with respect to the yellow patterns on the dorsal integument. Pigment cells were observed with electron microscope in order to determine the cell types of yellow markings. Quantitative analyses of pteridines in the albino were carried out by HPLC. The result indicated that the albino integument contain sepiapterin, biopterin, pterin, isoxanthopterin as in the wild type and the red mutant strain. The total amount of the four pteridines in the albino was about half as much as that in the red phenotype for both males and females, respectively. Males and females showed almost the same totals and ratios of the four pteridines in the albino and red phenotypes. Therefore, pteridine contents in both phenotypes of A. vulgare may not be related to the activity of androgenic gland hormone. Yellow chromatophores of the albino and red phenotypes were morphologically identical, emitting a yellow fluorescence. These cells contained numerous electron-lucent pigment organelles which were similar to pteridine granules of the wild type.

Hepatocyte growth factor induces transglutaminase activity that negatively regulates the growth signal in primary cultured hepatocytes

Transglutaminase (TGase) activity increased 2.5-fold at 6 h after treatment of rat hepatocytes with 117 nM hepatocyte growth factor (HGF). In the same manner, putrescine incorporation into proteins of cells occurred in HGF-treated cells but did not in those pretreated with monodansylcadaverine (MDC), a TGase inhibitor, even in the presence of HGF. These results suggest that HGF-induced TGase was active and catalyzed some cross-linkage reaction. Cycloheximide completely blocked the increase in TGase activity induced by HGF, suggesting that HGF stimulated de novo synthesis of TGase within 6 h. Both [35S]methionine incorporation and Northern blotting analyses supported this possibility. Pretreatment of cells with MDC additionally increased HGF-induced DNA synthesis and the ratio of cells in S-phase. Similarly, TGase antisense oligonucleotide inhibited de novo synthesis of TGase, resulting in increase in the ratio of S-phase cells in the presence of HGF. Analyses of cross-linking of HGF to the receptor indicated that the antisense oligonucleotide inhibited the downregulation of HGF receptor subsequent to HGF-addition. These results provide the first evidence for inducibility of de novo synthesis of TGase by HGF and suggest that TGase negatively regulates the growth signal of HGF through the downregulation of receptor.

Effects of exogenous transforming growth factor-beta 1 on spinal cord injury in rats

This study was undertaken to examine the effect of transforming growth factor-beta 1 (TGF-beta 1) administered into the subarachnoid space after spinal cord injury (SCI) on the increased production of inducible-nitric oxide synthase (i-NOS) in the injured spinal cord in rats. The expression of i-NOS mRNA after SCI was remarkably down-regulated by TGF-beta 1 in vivo. Rats treated with TGF-beta 1 showed a better outcome regarding hindlimb motor dysfunction in the first 5 days after injury compared to the saline-treated rats. However, the final outcome was not better and fibrous scar formation in the injured spinal cord was more evident, which was demonstrated as increased immunoreactivity of fibronectin in the later stage after SCI. These results provide evidence of both positive and negative contributions of TGF-beta 1 to the pathology associated with SCI.

Roles of nitric oxide in compression injury of rat spinal cord

Nitric oxide (NO) was measured directly after spinal cord injury (SCI) in rats by an ESR spin-trapping technique using Fe2+ and diethyldithiocarbamate (DETC). The levels of NO and lipid peroxides expressed as thiobarbituric acid reactive substances (TBARS) were increased by SCI in the injured region and the adjacent central region. Pretreatment with 30 mg/kg of NG-nitro-L-arginine methylester (L-NAME), an inhibitor of NO synthase, accelerated increases of the TBARS level and myeloperoxidase (MPO) activity in the injured tissue and caused deterioration of hind limb motor function after SCI, suggesting that NO formation by constitutive NO synthase (c-NOS) has a protective effect against cellular damage resulting from ischemia-reperfusion after SCI. Though c-NOS mRNA expression was not altered after SCI, inducible NO synthase (i-NOS) mRNA expression increased to a maximum of 24 h after SCI with progress of motor dysfunction. Intravenous injection of L-NAME (0.1 mg/kg) 6, 24, 48, and 72 h after SCI reduced the motor disturbance. These results indicate that NO induced by i-NOS may be neurotoxic in the subacute phase after SCI.

Pathogenesis of sports-related spondylolisthesis in adolescents. Radiographic and magnetic resonance imaging study

We reviewed radiographs and magnetic resonance images of 77 young athletes with spondylolysis and spondylolisthesis (more than 5% vertebral slip) (slip group). The results were compared with similar studies in 88 patients with spondylolysis only (nonslip group). Endplate lesions were found in all patients in the slip group and in 60 (68%) of those in the nonslip group. Slippage between the osseous and cartilaginous endplates was identified in the T1-weighted sagittal magnetic resonance images and categorized according to the type of slippage: total slip of L-5 or S-1, partial slip of L-5 or S-1, or a combination of these (mixed type). In a study of 31 patients whose slippages progressed, no slippage was associated with the early stage of a pars interarticularis defect. Most vertebral slippages developed or progressed in the cartilaginous or apophyseal stage of the lumbar skeletal age. Wedging of the L-5 vertebral body and rounding of the sacrum progressed as the slippage developed; these did not occur in the nonslip group. These results indicate that the advanced stage of a pars interarticularis defect in an immature spine is a risk factor for spondylolisthesis. The deformities of the lumbosacral spine are thought to be the secondary changes caused by vertebral slippage.

Transglutaminase induced by epidermal growth factor negatively regulates the growth signal in primary cultured hepatocytes

Transglutaminase (TGase) activity increased 2.5-fold at 6 h after treatment of rat hepatocytes with 17 nM epidermal growth factor (EGF). In the same manner, putrescine incorporation into the proteins of cells occurred in EGF-treated cells, but not in those pretreated with monodansylcadaverine (MDC), a TGase inhibitor, even in the presence of EGF. These results suggest that EGF-induced TGase was active and catalysed some cross-linkage reaction. Cycloheximide completely blocked the increase in TGase activity induced by EGF, suggesting that EGF stimulated de novo synthesis of TGase within 6 h. Furthermore, Northern blotting analysis indicated that EGF increased the expression of TGase mRNA. Pretreatment of cells with MDC additionally increased EGF-induced DNA-synthesis and the ratio of cells in S-phase. TGase antisense oligonucleotide inhibited de novo synthesis of TGase, resulting in increases in the ratios of S- and G2/M-phase cells in the presence of EGF. This effect was the result of inhibition of EGF-induced down-regulation of high-affinity receptor expression. These results suggest that the EGF-induced increase in TGase activity is a negative regulator of a growth signal in rat hepatocytes.

Characterization of rice alpha-amylase isozymes expressed by Saccharomyces cerevisiae

Two rice alpha-amylase isozymes, AmylA and Amy3D, were produced by secretion from genetically engineered strains of Saccharomyces cerevisiae. They have distinct differences in enzymatic characteristics that can be related to the physiology of the germinating rice seed. The rice isozymes were purified with immunoaffinity chromatography. The pH optima for Amy3D (pH optimum 5.5) and Amy1A (pH optimum 4.2) correlate with the pH of the endosperm tissue at the times in rice seedling development when these isozymes are produced. Amy3D showed 10-14 times higher reactivity to oligosaccharides than Amy1A. Amy1A, on the other hand, showed higher reactivity to soluble starch and starch granules than Amy3D. These results suggest that the isozyme Amy3D, which is expressed at an early stage of germination, produces sugars from soluble starch during the early stage of seed germination and that the isozyme Amy1A works to initiate hydrolysis of the starch granules.

Lesions of the lumbar posterior end plate in children and adolescents. An MRI study

We have reviewed 37 patients under the age of 18 years with lesions of the lumbar posterior end plate. All but one were active in sport, and most were seen because of low back pain. An abnormality was commonly found at the inferior rim of the body of L4 and at the superior rim of the sacrum. All adjacent intervertebral discs showed a decrease of signal intensity on the T2-weighted MRI. In 12 patients there was no interposed tissue at the posterior end-plate lesions. When disc material had migrated posteriorly none protruded beyond the posterior margin of the end plate, the dissociated portion of which was the main element compressing neural tissue. The posterior end-plate lesion should be regarded as a vertebral non-articular osteochondrosis.

Cranioplasty with split-thickness calvarial bone

Cranioplasty with autogenous split-thickness calvarial bone was performed in 10 patients. Follow-up for a mean of 19 months (range 2-43 mos) showed satisfactory protection of the brain and cosmetic reconstruction. No serious complication was seen except in one patient with postoperative epidural abscess. Split-thickness calvarial bone graft is recommended in patients with previous infection or high risk of infection, in poorly vascularized recipient sites resulting from multiple operations or irradiation, and in younger patients aged more than 7 years.

Lesions of the lumbar posterior end plate in children and adolescents. An MRI study

We have reviewed 37 patients under the age of 18 years with lesions of the lumbar posterior end plate. All but one were active in sport, and most were seen because of low back pain. An abnormality was commonly found at the inferior rim of the body of L4 and at the superior rim of the sacrum. All adjacent intervertebral discs showed a decrease of signal intensity on the T2-weighted MRI. In 12 patients there was no interposed tissue at the posterior end-plate lesions. When disc material had migrated posteriorly none protruded beyond the posterior margin of the end plate, the dissociated portion of which was the main element compressing neural tissue. The posterior end-plate lesion should be regarded as a vertebral non-articular osteochondrosis.

Bone mineral density of the lumbar spine in patients with ossification of the posterior longitudinal ligament of the cervical spine

Bone mineral density (BMD) of the lumbar spine in patients with ossification of the posterior longitudinal ligaments of the cervical spine (OPLL) was measured to elucidate the relation of spinal ossification with systemic hyperostotic condition. BMD in the lateral projection had a statistically significant correlation with that in the anteroposterior projection, and the former was considered to reflect the condition more accurately than was the latter, which may include the ossified spinal ligaments. BMD of patients with continuous and mixed types of OPLL was higher than that of those with the segmental type. Patients with OPLL and ossification of the other spinal ligaments had higher BMDs than did those without ossification. These results suggest that the BMD of the lumbar spine may reflect the systemic hyperostotic tendency and advancement of the ossification.

Pulmonary arteriovenous fistula associated with unequal branching of the pulmonary artery system

A 60-year-old woman was admitted to our hospital with shortness of breath and was diagnosed to have pulmonary arteriovenous fistula with unequal branching of the pulmonary artery system, as assessed by pulmonary angiography. The concomitant occurrence has not been reported previously. Although the etiology of these abnormalities is unknown, these abnormalities are considered to have occurred during an early stage of fetal development. The analysis of a concomitant occurrence of these abnormalities may be useful in elucidating the etiology of pulmonary arteriovenous fistula.

Purification of recombinant alpha-amylase by immunoaffinity chromatography with anti-peptide antibody

Adsorption characteristics of an anti-peptide antibody, obtained by immunization of eight amino acids in the C-terminal region of chimeric alpha-amylase of rice alpha-amylase isozymes, were studied by use of the chimeric enzyme and the peptide used for immunization. This anti-peptide antibody adsorbed the enzyme, as well as the peptide antigen, with sufficient affinity for immunoaffinity purification and was used for purification of the enzyme secreted from yeast cells. Chimeric alpha-amylase was purified by immunoaffinity chromatography to high purity in one step from the fermentation broth. One-third of the secreted enzyme was not adsorbed by the column of anti-peptide antibody because of processing in the C-terminal region.

[A case of hypertensive hypertrophy in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were observed after antihypertensive therapy]

A case of hypertensive hypertrophy is described in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were seen after 7 months of antihypertensive therapy. A 58-year-old man was diagnosed as having essential hypertension and hypertensive hypertrophy. The patient was treated with antihypertensive drugs and showed regression of left ventricular hypertrophy on electrocardiograms and echocardiograms. MIBG observations made before and after antihypertensive therapy showed increased heart-to-mediastinum activity ratio and decreased cardiac washout ratio. Despite the many theories addressing the mechanisms of regression of left ventricular hypertrophy, the process is still unclear. In the present case, the improvement of cardiac sympathetic nervous dysfunction might have been related to the regression of left ventricular hypertrophy because the abnormality in MIBG images improved. MIBG, therefore, may be helpful in clarifying the mechanisms of the regression of hypertensive hypertrophy.

Intradural extramedullary ependymoma. A case report

STUDY DESIGN

The present study illustrates a rare case of ependymoma of the spinal cord.

OBJECTIVES

An encapsulated intradural extramedullary ependymoma of the cervicothoracic spinal cord in a 24-year old woman is reported.

SUMMARY OF BACKGROUND DATA

Ependymoma is a glial tumor arising in the central nervous system. Intradural extramedullary ependymoma of the spinal cord is rare, and two cases were reported previously.

METHODS

The woman presented with myelopathy below C6. Magnetic resonance imaging showed an intradural tumor from C4 to T3 and no other lesion in the central nervous system. At surgery, the extramedullary tumor apparently was not attracted to the spinal cord or dura mater. Gross total removal was easily achieved under the operating microscope.

RESULTS

Histologic examination revealed the encapsulated tumor as an anaplastic ependymoma. Almost complete neurologic recovery was obtained.

CONCLUSION

The encapsulated appearance, lack of an apparent attachment to the central nervous system, and absence of signs of the primary neoplastic process within the brain or spinal cord suggested that the tumor arose from ectopic ependymal cells.

Motor recovery of patients presenting with motor paralysis and sensory sparing following cervical spinal cord injuries

We studied the neurological progress of 21 consecutive patients with cervical spinal cord injuries, presenting with sensory sparing but with complete motor paralysis below the level of their injury (Frankel B). All patients were admitted within 48 h of injury and treated conservatively with 6 weeks of bedrest and traction, followed by 6 weeks of bracing. The follow-up period was more than 1 year (49.6 months on average). Despite the initial absence of motor power in the lower limbs, seven patients recovered significant motor power and were able to walk. The preservation of pinprick sensation between the level of the injury and the sacral dermatomes was the best prognostic indicator for useful motor recovery with 75% of the patients regaining the ability to walk. This pattern of sensory sparing predicted a statistically significant better motor outcome than other patterns of sensory sparing. Although 50% of patients with no sacral sensation and/or with anal sensation on rectal examination recovered motor power, this recovery was functional in only one out of eight patients.

Glycosylation of CD44 negatively regulates its recognition of hyaluronan

Although CD44 is expressed on a wide variety of cell types, few of them use it to recognize the ligand hyaluronan (HA). A glycosylation-defective clone of Chinese hamster ovary cells (Lec 8) bound HA, demonstrating that complete processing of glycoproteins with addition of a full complement of sialic acid is not required. On the contrary, subsequent findings revealed that complex sugars on CD44 can actually inhibit ligand recognition. Two subclones of wild-type Chinese hamster ovary cells with similar amounts of surface CD44 were isolated on the basis of HA binding and found to differ with respect to CD44 size as well as staining with fluorescent lectins. Treatment of the nonbinding clone with tunicamycin reduced the size of the protein and allowed the cells to recognize HA via CD44. This function was also induced by treatment with deglycosylating enzymes (either a mixture of endoglycosidase F and N-glycosidase F or neuraminidase alone). A possible role for glycosylation in regulation of adhesion was then sought with a series of normal and transformed murine cells. Disruption of glycosylation or treatment with deglycosylating enzymes did not induce ligand binding in an interleukin 7-dependent pre-B cell line, and splenic B cells also appeared to be in an inactive state. Some normal B cells acquired the ability to recognize HA after stimulation with lipopolysaccharide or interleukin 5 and had distinctive surface characteristics (loss of immunoglobulin D and acquisition of CD43). An additional subset of activated cells might have been in a transitional state, because the cells bound ligand after neuraminidase treatment. The ligand-binding ability of a purified CD44-immunoglobulin fusion protein dramatically increased after neuraminidase treatment. Thus, differential glycosylation of this molecule is sufficient to influence its recognition function. Cell adhesion involving HA can be regulated by multiple mechanisms, one of which involves variable glycosylation of CD44.

Monoclonal antibodies to CD44 and their influence on hyaluronan recognition

Antibodies to CD44 have been used to inhibit a variety of processes which include lymphohemopoiesis, lymphocyte migration, and tumor metastasis. Some, but not all, CD44-mediated functions derive from its ability to serve as a receptor for hyaluronan (HA). However, sites on CD44 that interact with either ligands or antibodies are poorly understood. Interspecies rat/mouse CD44 chimeras were used to analyze the specificity of 25 mAbs and to determine that they recognize at least seven epitopes. Amino acid substitutions that resulted in loss of antibody recognition were all located in the region of homology to other cartilage link family proteins. While at least five epitopes were eliminated by single amino acid replacements, multiple residues had to be changed to destroy binding by other antibodies. One antibody was sensitive to changes in any of three separate parts of the molecule and some antibodies to distinct epitopes cross-blocked each other. Certain antibodies had the ability to increase HA binding by lymphocytes but this did not correlate absolutely with antibody specificity and was only partially attributable to CD44 cross-linking. Antibodies that consistently blocked HA recognition were all sensitive to amino acid changes within a short stretch of CD44. Such blocking antibodies interacted with CD44 more strongly than ligand in competition experiments. One large group of antibodies blocked ligand binding, but only with a particular cell line. This detailed analysis adds to our understanding of functional domains within CD44 and requirements for antibodies to influence recognition of one ligand.