The structure of siglec-7 in complex with sialosides: leads for rational structure-based inhibitor design

Siglecs (sialic acid binding Ig-like lectins) are transmembrane receptors for sialylated glycoconjugates that modulate cellular interactions and signalling events in the haematopoietic, immune and nervous systems. Siglec-7 is a structural prototype for the recently described family of immune inhibitory CD33-related siglecs and is predominantly expressed on natural killer cells and monocytes, as well as subsets of CD8 T-cells. Siglec-specific inhibitors are desired for the detection of masked and unmasked forms of siglecs, to aid in dissection of signalling pathways and as tools to investigate siglecs as potential therapeutic targets. As a first step towards this end, we present the crystal structure of siglec-7 in complex with a sialylated ligand, the ganglioside analogue DSLc4 [alpha(2,3)/alpha(2,6) disialyl lactotetraosyl 2-(trimethylsilyl)ethyl], which allows for a detailed description of the binding site, required for structure-guided inhibitor design. Mutagenesis and binding assays were used to demonstrate a key structural role for Lys131, a residue that changes conformation upon sialic acid binding. Differences between the binding sites of siglec family members were then exploited using alpha-methyl Neu5Ac (N-acetylneuraminic acid) as a basic scaffold. A co-crystal of siglec-7 in complex with the sialoside inhibitor, oxamido-Neu5Ac [methyl alpha-9-(amino-oxalyl-amino)-9-deoxy-Neu5Ac] and inhibition data for the sialosides gives clear leads for future inhibitor design.

Initial strength of highpressed extrusion poly-L-lactide screw

We developed a poly-L-lactide material strengthened by a highpressed extrusion technique. The bending strength of a rod made of that material is higher than that of the same size rods made of poly-L-lactide strengthened by drawing technique, which has been used in clinical cases. The purposes of this study were, first to clarify if the initial strength of extrusion-strengthened poly-L-lactide screws is higher than that of draw-strengthened poly-L-lactide screws, and, secondly to investigate the safe torque for driving the screws in clinical usage. In accordance with AO screw design, five kinds of screws were manufactured. In a pull-out test and a twisting test using a DYRACON blocks, the strength of the highpressed extrusion-strengthened poly-L-lactide material was also higher than that of the draw-strengthened poly-L-lactide material after milling into screws. In the simulation using minipig bones and the 4.5 mm psi cortical screws, when the thickness was below 0.5 mm, between 0.5 and 2 mm or over 3 mm, the break locations were in the cortical bone, the thread of the screw and the under head fillet respectively. In the simulation using minipig bones and the 4.0 mm psi cancellous screws, breakage occurred not on the screws but on the cancellous bone in all screws.

Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles

PURPOSE

We have previously shown that the combination of low-intensity resistive exercise and moderate vascular occlusion induces in humans a marked increase in growth hormone secretion and muscular hypertrophy. The present study investigated the effects of vascular occlusion on the size of thigh muscles in patients who underwent an operation for the reconstruction of the anterior cruciate ligament to see whether it attenuates the disuse muscular atrophy without any exercise combined.

METHODS

Two sessions of occlusive stimulus, each consisting of five repetitions of vascular occlusion (mean maximal pressure, 238 mm Hg) for 5 min and the release of occlusion for 3 min, were applied daily to the proximal end of the thigh from 3rd to 14th days after the operation. Changes in the cross-sectional area (CSA) of thigh muscles were analyzed with magnetic resonance images taken on the 3rd and 14th day after the operation.

RESULTS

Without occlusive stimulus (control), the CSAs of knee extensors and flexors decreased by 20.7 +/- 2.2% and 11.3 +/- 2.6% (mean +/- SEM, N = 8), whereas with the occlusive stimulus, they decreased by 9.4 +/- 1.6% and 9.2 +/- 2.6% (N = 8), respectively. The relative decrease in CSA of knee extensors was significantly (P < 0.05) larger in the control group than in the experimental group.

CONCLUSION

The results indicate that the occlusive stimulus effectively diminishes the postoperation disuse atrophy of knee extensors.

Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans

Acute and long-term effects of resistance exercise combined with vascular occlusion on muscular function were investigated. Changes in integrated electromyogram with respect to time (iEMG), vascular resistive index, and plasma lactate concentration were measured in five men either during or after elbow flexion exercises with the proximal end of the arm occluded at 0-100 mmHg. The mean iEMG, postexercise hyperemia, and plasma lactate concentration were all elevated with the increase in occlusion pressure at a low-intensity exercise, whereas they were unchanged with the increase in occlusion pressure at high-intensity exercise. To investigate the long-term effects of low-intensity exercise with occlusion, older women (n = 24) were subjected to a 16-wk exercise training for elbow flexor muscles, in which low-intensity [ approximately 50-30% one repetition maximum (1 RM)] exercise with occlusion at approximately 110 mmHg (LIO), low-intensity exercise without occlusion (LI), and high- to medium-intensity ( approximately 80-50% 1 RM) exercise without occlusion (HI) were performed. Percent increases in both cross-sectional area and isokinetic strength of elbow flexor muscles after LIO were larger than those after LI (P < 0.05) and similar to those after HI. The results suggest that resistance exercise at an intensity even lower than 50% 1 RM is effective in inducing muscular hypertrophy and concomitant increase in strength when combined with vascular occlusion.

Reduced expression of E-cadherin in oral squamous cell carcinoma: relationship with DNA methylation of 5' CpG island

E-cadherin, a Ca2+-dependent cell-cell adhesion molecule, is involved in the maintenance of the epithelial phenotype. The reduction of its expression is considered to be important in the invasive and metastatic potential of carcinomas. A series of 52 primary oral squamous-cell carcinomas (SCCs) were studied immunohistochemically for E-cadherin expression in microwave-treated paraffin-embedded sections using a monoclonal antibody (HECD-1). Significant correlation was found between reduced E-cadherin expression and tumor dedifferentiation, grade of invasiveness, and lymph node metastasis. The possibility of E-cadherin gene mutation was also investigated by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), but none was found. In addition, to clarify the CpG methylation state around E-cadherin gene promoter in oral SCC, we examined DNA samples by PCR assay after restriction digestion with methylation-sensitive enzyme HpaII. CpG methylation was found in 9 (17%) of 52 primary oral SCCs, but not in the corresponding normal tissues. In particular, 8 of the 9 methylated cases showed reduced expression of E-cadherin and histologically diffuse invasion type of tumor. These results suggest that reduction of E-cadherin expression is associated with the progression of human oral SCCs, and CpG methylation of E-cadherin gene promoter causes reduction of E-cadherin expression in the tumor, resulting in acquisition of the invasive phenotype.

Chronic exertional compartment syndrome in lower legs: localization and follow-up with thallium-201 SPECT imaging

The purpose of this study was to ascertain whether 201Tl SPECT imaging of the leg is useful in precise localization of the ischemic compartment involved in chronic exertional compartment syndrome (CECS).

METHODS

Imaging and quantitative analyses of postexercise 201Tl SPECT leg examinations were retrospectively performed in nine patients with clinically diagnosed CECS and eight control subjects. Imaging and quantitative criteria for the ischemic compartment were decreased 201Tl perfusion less than the lower limits of normal, which were defined as 2 s.d. below the mean percentage uptake of the control subjects. The SPECT imaging results were compared with those of quantitative analysis, postoperative SPECT images and clinical diagnoses.

RESULTS

Postexercise normal legs had nonuniform 201Tl distribution in both legs and in the four compartments. Lower limits of normal mean percentage 201Tl uptake were about 60% for the anterior compartment and about 50% for the other three compartments. Redistribution was observed in 67% of normal compartments in the control subjects. The SPECT images demonstrated 16 ischemic compartments in eight of the nine patients. The SPECT results were consistent with those of quantitative analysis. There were discrepancies between the clinical and SPECT diagnoses in six legs (33% of the 18 legs) of five patients. Postoperative SPECT demonstrated 201Tl perfusion was improved in all involved compartments for that fasciotomy was performed.

CONCLUSION

Thallium-201 SPECT imaging of the legs can easily provide precise localization of the ischemic compartment, which is demonstrated as decreased 201Tl distribution on the stress image. This technique is promising for the screening and follow-up of CECS.

[Association between expression of integrin (VLA-3, VLA-5) and malignancy in human colon-cancer]

The expression of the VLA-integrins beta 1, -2, -3, -5, -6 and alpha v beta 3 was studied immunohistochemically in the tissue sample from human colon-cancer. Furthermore, histological stage-grouping of the colon-cancer (I-V), additional vascular invasion such as lymphatic and blood-vessel invasion, was made to express the malignancy of the carcinoma, for making a comparison with the expression of the integrins. Immunohistologically, beta 1, VLA-2, and alpha v beta 3 were mildly expressed in the carcinoma cells and VLA-6, markedly expressed. These findings were not correlated with the malignant stage-grouping. For VLA-3, the carcinoma showed mild to marked expression with a diffuse distribution on the cell surface in the peripheral area of the carcinoma, nearly correlating with the histological stage of malignancy. While, the expression of VLA-5 was almost absent in the carcinoma. These results suggest that the enhanced expression of VLA-3 with suppressed expression of VLA-5 is functionally important for the carcinoma cell invasion and also for the metastasis.

Correlation between angiographic features and pathologic changes in breast carcinoma

The correlation between angiographic tumor blushing and underlying pathologic factors was studied. Twenty female patients with breast cancer were divided into three groups according to the degree of tumor blushing. Primary tumors were divided into three areas: marginal, central and intermediate areas. In each area, the number of blood vessels per 10(4) mu 2 was randomly counted in 10 fields and a mean value of vessels was compared among the three groups. It was found that the following pathologic findings were significantly related to strong angiographic staining: (i) well-circumscribed border; (ii) large tumor nest; (iii) severe inflammatory cell infiltration; (iv) mild stromal fibrosis; and (v) absence of lymph node metastasis. The mean value of blood vessels in the strongly positive group was significantly increased in the overall and the intermediate areas. The density of the vessels in the intermediate area was thus thought to be responsible for the tumor blushing.

[Dementia and amyotrophy in Kufs disease. The adult type of neuronal ceroid lipofuscinosis]

A 26-year-old housewife, born of consanguineous parentage, began to have gait and speech disturbance. Her brother had died from suffocation because of dysphagia. At thirty-two, she developed difficulty in swallowing, clumsiness and incontinence. When she was thirty-six she had pseudobulbar palsy, vertical gaze paresis, hyperreflexia and muscular atrophy of the upper half of the body. CT scan showed cerebral atrophy. Her mental function progressively deteriorated and amyotrophic lateral sclerosis associated with dementia was suspected. She died at the age of thirty-seven. Diagnosis was made only by autopsy. There was no particular general pathologic finding excepting aspiration pneumonia. Microscopical examination revealed numerous distended neurons with accumulation of light brown pigments by Luxol fast blue/H & E stains, especially in hypothalamus, substantia nigra and nuclei of oculomotor nerves. To a lesser extent such neurons were noted ubiquitously. The stored material was mainly composed of lipofuscin and ceroid. Ultrastructurally they presented the various structures which have previously been reported, except for finger print profiles. The pigmentary deposits were shown to be immunoreactive with polyclonal antibody directed against amyloid beta-protein.

[A case report of atypical coarctation of the aorta with coarctation and left subclavian arterial aplasia]

A 18 year-old female was admitted to our hospital with hypertension of 190/100 mmHg in her right arm and 140/110 mmHg in the left arm. Femoral arterial pulsation was not palpable. Her physical status and growth of the lower limbs were normal. Aortography demonstrated slight coarctation with a pressure gradient of 10 mmHg and descending aortic stenosis with a pressure gradient of 80 mmHg. Main three branches from aortic arch were anatomically normal. However, the left subclavian artery distal to the origin of the left vertebral artery was not visualized and the axillary artery was perfused by collaterals. Atypical coarctation was replaced using a woven Dacron graft of 14 x 40 mm. Postoperatively proximal pressure decreased from 180/113 to 156/98 mmHg and there was no pressure gradient between proximal and distal of the graft. After six months blood pressure in the right arm gradually decreased to 120/78 mmHg.

Incarnal. A new antibacterial sesquiterpene from Basidiomycetes

A new sesquiterpene, incarnal, was isolated from culture fluid of Gloeostereum incarnatum (Japanese name: Nikawaurokotake). Incarnal inhibited the growth of gram-positive bacteria at 6.25-12.5 micrograms/ml. The structure of incarnal has been determined to be (1-hydroxy-2,10,10-trimethyl)-3-methylene- tricyclo[6.3.0.0(2.6)]undec-5,7-diene-4,9-dione by X-ray diffraction and spectroscopic methods.

[Papillary adenoma of the prostatic urethra--a case report and review of 61 cases in Japan]

We report a case of papillary adenoma of the prostatic urethra composed of prostatic-type epithelial tissue. The patient was a 48-year-old male with complaint of urethral bleeding. Tumor was transurethrally resected. Sixty one such cases (males, 17-82 years old) have been reported in Japan. Of these patients, 31 (51%) were between 30 and 49 years old, the mean age was 43.9 years old. The lesion was located on the verumontanum (20%) and around the verumontanum (80%). The general symptom was hematuria (65.6%) and sometimes hemospermia (11.5%), dysuria (9.8%). Cautious fulguration was generally performed and the recurrence was reported in 4 cases (6.7%). It is believed to be a completely benign lesion, since no cases of malignant transformation has been reported. However, we must note that 3 cases (4.9%) had a malignant tumor in the lower urinary tract (bladder 1, urethra 2) at the same time.

Stage-specific localization of cytoskeletal actin mRNA in murine seminiferous tubules and intestinal epithelia as demonstrated by in-situ hybridization

In-situ hybridization experiments have been performed using isoactin (beta and gamma)-specific riboprobes in various tissues of the rat and mouse. Distribution of the grains of actin mRNAs for both beta and gamma types was similar throughout sections of the rat testis. Although both mRNAs were evenly distributed in the seminiferous tubule, extremely heavy labeling was observed in about 10% of the seminiferous tubules that could be identified as stage XII of spermatogenesis. At high magnification, grains of the mRNA were found in the cytoplasm of elongating spermatids and in the Sertoli cell cytoplasm at the adluminal side. Much higher density of the grains of mRNA was observed in the neck region of the spermatids at stage XII. Thus, the dense distribution of cytoskeletal actin mRNAs is stage-specific in the tubule during spermatogenesis in the rat. The high expression of both beta and gamma actin mRNAs was also observed in the epithelial cells of the intestinal crypts.

[A radical operation of Chiari's disease using the internal shunt tube of the inferior vena cava]

A case with the Budd-Chiari syndrome due to the right hepatic occlusion who was successfully operated by using the internal shunt tube of the inferior vena cava was reported. The patients was 33 year old male. Midsternal incision and right subcostal oblique incision were made and the internal shunt tube was inserted through the right auricle to the inferior vena cava. The hepatic vein was approached through the longitudinal suprahepatic caval venotomy. Then membranous obstruction in the right hepatic vein ostia was resected. Mesenteric venous pressure dropped immediately from 360mm H2O to 160mm H2O by direct manometry. All the blood bled from the right hepatic vein was transfused through the internal shunt tube to the right atrium. The patient tolerated the procedure and his postoperative course was free from the complication. The resected membrane was congenital anomaly and an operative liver biopsy was demonstrated the evidence of congestive liver with fibrosis.

A histopathologic study of early hepatocellular carcinoma

In a series of 94 autopsy cases of hepatocellular carcinoma (HCC), 8 cases of minute HCC (less than 3.5 cm in diameter) were included. These cases had some additional nodular foci that revealed a possible histogenesis of HCC. The lesion was first noted as a group of basophilic liver cell cords in a limited area of a hyperplastic nodule. The cords showed acinar formation, bile congestion, and increase of stromal fibers with disappearance of sinusoids. When certain numbers of lobules were occupied by the basophilic liver cells, a dysplastic nodule was produced wherein the portal triads tended to disappear. Despite marked necrotic tendency, the liver cells proliferated actively and replaced the adjacent cirrhotic lobules. The process might be induced and enhanced by repeated episodes of necrosis and regeneration occurring in cirrhotic livers. Some minute HCC nodules had common features with those seen in the dysplastic nodule. Histologic findings of minute HCC nodules were also described and discussed in terms of their growth pattern.

Computed tomography of the pectoralis muscles in Poland's syndrome

Computed tomography (CT) can demonstrate disorders of the chest wall muscles clearly. CT scans of the thorax were carried out in seven patients with Poland's Syndrome. All patients with Poland's Syndrome had the clavicular portion of the pectoralis major, but were lacking the sternocostal portion of the pectoralis major. The pectoralis minor was absent in four of seven patients.

Dermatoglyphics in typical cleft hand

Dermatoglyphic prints of the typical cleft hand with a rudiment of the middle metacarpal showed that a whorl pattern was present on the ulnar margin of the V-shaped defect, suggesting the fingertip pattern of the middle finger.

An experimental model for lymphatic metastasis in rats

An experimental model was described for inducing spontaneous lymph node metastasis, in which tumor cells of the rat ascites hepatoma AH-109A were transplanted into the subcutaneous tissue of the penis, which is rich of lymph plexus. Growth of tumor at the site of transplantation was measured serially and metastasis was recognized by palpation in the inguinal lymph nodes initially, and then in the axillary and lumbar nodes. When animals were sacrificed 12 days after transplantation, these lymph nodes were weighed and high percentage of metastasis was confirmed by histological examination. As an experimental model of lymph node metastasis, the usefulness of this method was discussed.