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Biomedical subjects

Hiroyuki Nakagawa

Publications and source records attributed to Hiroyuki Nakagawa.

At least 19 recordsLinked to original sources

Radiographic evaluation of vertebral fractures in osteoporotic patients.

Vertebral fractures, are a serious clinical problem for elderly osteoporotic patients, have been increasingly recognized and are now common. On the assumption that it is difficult to diagnose osteoporotic vertebral fractures on plain radiographs, we studied 78 consecutive patients aged over 50 years with severe back pain with or without minor trauma. All patients had been admitted to our department and had undergone radiographic examinations including plain radiography, magnetic resonance imaging (MRI) and bone scintigraphy. Surprisingly, 74 of the patients (94.9%) with severe back pain had vertebral fractures. Low intensity on T1-weighted MRI indicated that the severe back pain was a symptom of vertebral fracture. The patients were divided into two groups: those with total, and those with partial T1-weighted hypointensity of the vertebral body on MRI. Thirty-five of the vertebral fractures (47.3%) were not detectable on plain radiographs, and patients without trauma showed vertebral deformity more frequently than those with trauma. The patients were treated conservatively with bed rest until the severe back pain had subsided, after which they were evaluated clinically. The average period of bed rest was 22.3 days, which did not differ significantly in relation to the occurrence of trauma, the extent of the signal change in the vertebral body on MRI or the presence of vertebral deformity. Even without vertebral deformity or trauma, vertebral fractures required long periods of bed rest for pain relief and entailed serious clinical problems.

Aged↗

Optimal duration of conservative treatment for lumbar disc herniation depending on the type of herniation.

Six hundred and six clinical records of patients who were admitted to the Department of Orthopaedic Surgery, Suwa Red Cross Hospital, Nagano, Japan, due to lumbar disc herniation (LDH) between 1991 and 2002 were reviewed to determine the ideal conservative treatment period in relation to different types of LDH: contained and non-contained. Since 1997, we have prolonged in-hospital conservative treatment over a few weeks, which resulted in a decrease in the number of surgeries for non-contained LDH, especially of surgeries performed within 1 month. The number of surgeries for contained LDH did not decrease. The preoperative period of non-contained LDH was significantly shorter than that of contained LDH. These results indicate that for patients who have non-contained LDH, intensive conservative treatment may avoid a surgical procedure. For those patients who have contained LDH, conservative treatment should not be prolonged. We believe that the optimal duration of intensive conservative therapy should be less than 1 month.

Adolescent↗

Differences in the regulation of microtubule stability by the pro-rich region variants of microtubule-associated protein 4.

We have recently reported a neural variant of microtubule-associated protein 4 with a short pro-rich region (MAP4-SP). Here, we show that the neural MAP4 has reduced microtubule-stabilizing activity, compared to the ubiquitous MAP4 with a long pro-rich region (MAP4-LP), both in vitro and in vivo. Fluorescence recovery after photobleaching analyses revealed that the interaction of MAP4-SP with the microtubules is very rapid, with a half-time of fluorescence recovery of 7 +/- 2.36 s, compared to 19.5 +/- 3.03 s in case of MAP4-LP. The dynamic interaction of MAP4-SP with microtubules in neural cells may contribute to the dynamic behaviors of extending neurites.

Animals↗

Short-term retention of actin filament binding proteins on lamellipodial actin bundles.

Actin filaments are organised into sub-compartments of meshwork and bundles in lamellipodia. Localisation of fascin, the LIM and SH3 domain protein 1 (lasp-1), and lasp-2 to the bundles suggest their involvement in that organisation; however, their contributions remain unclear. We have compared the turnover of these proteins with actin at the bundle. After photobleaching, EGFP-actin recovered inwards from the bundle tip, consistent with the retrograde flow by treadmilling. In contrast, the recovery of EGFP-fascin, -lasp-1 and -lasp-2 occurred from the anterograde direction. These results suggest that these molecules would participate in the stabilisation of bundles but not in initiation.

Actin Cytoskeleton↗

Usefulness of white blood cell differential for early diagnosis of surgical wound infection following spinal instrumentation surgery.

STUDY DESIGN: The white blood cell (WBC) count and WBC differential were measured prospectively in patients after spinal instrumentation surgery with or without surgical wound infection. OBJECTIVES.: To investigate the usefulness of WBC differential for early diagnosis of surgical wound infection after spinal instrumentation surgery. SUMMARY OF BACKGROUND DATA: Renewed elevation of C-reactive protein (CRP) or WBC, gallium scan, and CRP/transthyretin mass concentration ratio were reported for early diagnosis of surgical wound infection. METHODS: A total of 39 patients were enrolled in this study: 13 patients who developed wound infection within 2 weeks after spinal instrumentation surgery (infection group) and 26 patients who were comparable with those patients included in the infection group with regard to age, sex, and surgical techniques used (control group). The WBC count and WBC differential were determined before and after surgery. RESULTS: In both groups, WBC and percentage and number of neutrophils showed nearly same change until postoperative 4 days (day 4). However, in the infection group, these parameters had increased after day 4. In both groups, the percentage and number of lymphocytes decreased to 10% or less and 1,000/microL or less on day 1, respectively. These lymphocyte parameters began to gradually normalize on day 4 and returned to the preoperative level 3 weeks after surgery in the control group. On the other hand, these parameters remained 10% or less and 1,000/muL or less until day 11 in the infection group. In patients with infection, the percentage and number of lymphocytes significantly decreased as early as on day 4. CONCLUSION: Lymphopenia represents immunodepression status, thus indicating the increased susceptibility to infection, which may lead to the development of postoperative infection. If lymphopenia is diagnosed as early as possible, surgical wound infection can be treated promptly without removing the instruments.

Adolescent↗

Ferritin forms dynamic oligomers to associate with microtubules in vivo: implication for the role of microtubules in iron metabolism.

Ferritin, a ubiquitously distributed iron storage protein, has been reported to interact with microtubules in vitro (Hasan et al., 2005, FEBS journal 272:822-831). Here, we demonstrate that ferritin binds with the microtubules in an oligomeric form and that the microtubule-bound ferritin contains more than two-fold amount of iron compared to the unbound ferritin fraction in vitro. Indirect immunofluorescence microscopy showed that a significant fraction of the ferritin molecules colocalized with the microtubules as oligomers in a wide variety of cell lines. These findings are consistent with the immediate oligomerization of rhodamine-labeled ferritin, microinjected in living human hepatoma cells. Ferritin oligomers were dynamic in the cytoplasm, and an anti-microtubule drug significantly inhibited their intracellular movement. Treatment of cells with an iron donor, ferric ammonium citrate, remarkably increased the number of cells containing ferritin oligomers. On the other hand, when the cells, such as mouse neuroblastoma cells, were deprived of iron, ferritin oligomers were localized in the microtubule dense, neurite shafts, but were disappeared from the microtubule deficient neurite tips. These data indicate that the microtubules provide a scaffold for the cytoplasmic distribution and transport of the iron-rich ferritin and implicate the role of microtubules in iron metabolism.

Animals↗

Pituitary stalk compression by the dorsum sellae: possible cause for late childhood onset growth disorders.

PURPOSE: The purpose of this study was to evaluate the relationship between pituitary stalk compression by the dorsum sellae and clinical or laboratory findings in short stature children. MATERIALS AND METHODS: We retrospectively reviewed magnetic resonance images of the pituitary gland and pituitary stalk for 34 short stature children with growth hormone (GH) deficiency and 24 age-matched control cases. We evaluated the degree of pituitary stalk compression caused by the dorsum sellae. Body height, GH level, pituitary height and onset age of the short stature were statistically compared between cases of pituitary stalk compression with associated stalk deformity and cases without compression. RESULTS: Compression of the pituitary stalk with associated stalk deformity was seen in nine cases within the short stature group. There were no cases observed in the control group. There were no significant differences found for body height, GH level and pituitary height between the cases of pituitary stalk compression with associated stalk deformity and cases without compression. However, a significant difference was seen in the onset age between cases with and without stalk compression. CONCLUSION: Pituitary stalk compression with stalk deformity caused by the dorsum sellae was significantly correlated with late childhood onset of short stature.

Adolescent↗

Displacement of the facial nerve course by vestibular schwannoma: preoperative visualization using diffusion tensor tractography.

PURPOSE: To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings. MATERIALS AND METHODS: The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facial nerve were constructed. We assessed the success rate for tract construction and evaluated the agreement between tractography findings and surgery. RESULTS: We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic. CONCLUSION: Tractographs constructed using MR tensor images enabled us to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.

Adult↗

Pseudoarthrosis of vertebral fracture: radiographic and characteristic clinical features and natural history.

BACKGROUND: We examined mobility based on radiographic appearance, clinical appearance, and the natural course of osteoporotic vertebral pseudoarthrosis (VPA) in a prospective study in 34 consecutive cases of VPA in 27 patients with osteoporosis. METHODS: Conventional lateral, lateral flexion, and extension stress radiography (XP) and supine cross-table lateral XP were performed. Anterior vertebral body height and vertebral kyphotic angle were measured to assess vertebral mobility. If vertebral cleft or vertebral instability, which means a difference in vertebral body height between conventional and supine cross-table lateral XP, was present, VPA was diagnosed. Back pain was classified into five grades. RESULTS: The average anterior vertebral height was 9.9 +/- 5.6 mm on conventional lateral XP; it increased to 11.4 +/- 6.5 mm on extension stress XP (not significant) and 18.3 +/- 5.7 mm on cross-table lateral XP (significant). The vertebral kyphotic angle was 24.1 degrees +/- 9.7 degrees on conventional lateral XP; it decreased to 21.6 degrees +/- 9.8 degrees on extension stress XP (not significant) and 11.8 degrees +/- 8.5 degrees on cross-table lateral XP (significant). Intravertebral clefts were detected by conventional lateral XP, extension stress XP, and supine cross-table XP in 3 of 34 (8.8%), 7 of 21 (33.3%), and 28 of 34 (82.4%) vertebral compression fractures (VCFs), respectively. Surgical treatment was performed in seven patients (two because of severe pain and five because of neurological deficits) and in one patient who died. Except in these eight patients, back pain decreased by at least one grade with time in 18 of 19 patients (95%) in whom the clinical course was analyzed. Radiographic follow-up using supine cross-table XP was performed in 15 of 19 patients. Although 11 of these 15 patients (73%) showed vertebral instability on supine cross-table lateral XP, 10 of 11 patients (91%) did not complain of intolerable back pain during daily activity at the final follow-up. CONCLUSIONS: VPA is often detected on supine cross-table lateral XP but not usually on extension stress XP. Despite the presence of vertebral instability, many patients did not complain of intolerable back pain during their daily activity. Surgical treatment to alleviate back pain should be performed for painful VPA after conservative treatment for about 4 months.

Aged↗

Changes in total alkaline phosphatase level after hip fracture: comparison between femoral neck and trochanter fractures.

BACKGROUND: Biochemical bone metabolic markers are affected by fractures, and total alkaline phosphatase (ALP) is considered one of the bone formation markers. Only a few reports have dealt with changes in bone formation markers during the healing process of bone fragility hip fractures. Despite the difference in the amount of callus formation and bone fusion rate, no significant differences in longitudinal change of total ALP between femoral neck and trochanter fracture have been reported. METHODS: A total of 69 osteoporotic patients with femoral neck or trochanter fracture whose serum concentrations of total ALP were examined at least four times at six periodic examination points (1, 2, 3, 4, 6, and 8 weeks after surgery) and whose state of bone union was obtained within 24 weeks after surgery were selected for this retrospective study. The characteristic longitudinal change of total ALP during the healing process was shown, and the possibility of total ALP as a predictive factor for the state of osteosynthesis of hip fractures is discussed. RESULTS: Changes in the total ALP level according to the healing process were similar for femoral neck and trochanter fractures. The concentration of total ALP rose to a maximum at 3 weeks after surgery and then gradually decreased for both fractures. However, the range of change was significantly greater for trochanter fractures than for femoral neck fractures. For trochanter fractures, total ALP decreased from 3 to 6 weeks after surgery in all but one patient. CONCLUSIONS: Increases in the concentration of total ALP after surgery and the subsequent decreases may reflect the normal healing process. A significant difference in the changes of total ALP after surgery between femoral trochanter and neck fractures was shown. Periodic measurement of total ALP might be useful for obtaining information on the osteosynthesis state.

Age Factors↗

Chemical constituents from the peels of Citrus sudachi.

A methanol extract of the peels of Citrus sudachi gave five new compounds (1-5) and 27 known compounds. The structures were elucidated on the basis of spectroscopic evidence. Several of these compounds were assayed for antimicrobial activity against methicillin-resistant Staphylococcus aureus and Helicobacter pylori, and sudachitin (6) and 3'-demethoxysudachitin (7) were the most active.

Anti-Bacterial Agents↗

Retention behavior of neutral solutes in pressurized flow-driven capillary electrochromatography using an ODS column.

Several alkyl benzenes are separated by pressurized flow-driven capillary electrochromatography using a temperature-controlled capillary column packed with octadecyl siloxane-modified silica gel, and the effect of applied voltage on the retention is investigated. The van't Hoff plot shows good linearity at the column temperature between 305 and 330 K under applications from -6 to +6 kV. The applied voltage causes a relatively large variation in the enthalpy and the entropy of transfer of the solute from the mobile phase to the stationary phase (> 20%). However, the direction of variation in the enthalpy is almost opposite to that in the entropy, both of which might compensate each other. Therefore, the retention factor is not significantly varied (< 4%) by the application of voltage.

Journal Article↗

Aggregation of partially unfolded Myosin subfragment-1 into spherical oligomers with amyloid-like dye-binding properties.

Proteolytic myosin subfragment 1 (S1) is known to be partially unfolded in its 50-kDa subdomain by mild heat treatment at 35 degrees C [Burke et al. (1987) Biochemistry 26, 1492-1496]. Here, we report that this partial unfolding is accompanied by aggregation of S1 protein. Characteristics of the aggregate thus formed were: (i) formation of transparent sediment under centrifugation at 183,000 x g; (ii) amyloid-like, dye-binding properties such as Congo red-binding and Thioflavin T fluorescence enhancement; (iii) a uniformly sized spherical appearance in electron micrographs; and (iv) sensitivity to tryptic digestion. Gel filtration analysis of the aggregation process indicates that the spheroid was formed through an intermediate oligomeric stage. The aggregate inhibited spontaneous aggregation of an isolated 50 kDa fragment into a large amorphous mass. The remaining native regions in the partially unfolded S1 were probably responsible for this effect. These results show that, unlike the 50-kDa fragment, the partially unfolded S1 molecules do not form amorphous aggregates but assemble into spherical particles. The native regions in partially unfolded S1 may be a determinant of aggregate morphology.

Amyloid↗

Fourier transform infrared spectroscopic analysis of the intact zona pellucida of the mammalian egg: changes in the secondary structure of bovine zona pellucida proteins during fertilization.

The zona pellucida is the acellular transparent envelope surrounding the mammalian oocyte. An analysis of the changes in the structures of zona pellucida proteins is essential for understanding the molecular mechanisms underlying the important physiological roles of the zona during fertilization and preimplantation. The hardening of the zona caused by the structural changes during fertilization is generally accepted to be responsible for blocking polyspermy. In this study, we analyzed changes in the secondary structure of the zona during fertilization by Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy. The predominance of beta-sheet structure in porcine ovarian egg zona proteins in water was ascertained using FTIR spectra. Alpha-helix structure was also present. The attenuated total reflection (ATR)-FTIR spectrum of intact, unsolubilized porcine zonae pellucidae from ovarian eggs indicated that the zona proteins in the native zona pellucida also have beta-structure as the main constituent. Attenuated total reflection-FTIR spectroscopy of intact bovine zona pellucida obtained from ovarian and fertilized eggs at the blastocyst stage revealed that the beta-structure content increased during fertilization. Furthermore, a reduction of the thickness of the zona during fertilization was observed using transmission electron microscopy. Therefore, the change in the zona architecture that causes hardening of the zona during fertilization is accompanied by changes in the secondary structure of the zona proteins.

Animals↗

Effect of the net surface charge density of heptakis-6-bromo-6-deoxy-beta-cyclodextrin bonded silica gels on the retention behaviors of neutral cresol isomers in HPLC.

The effect of the surface charge density of heptakis-6-bromo-6-deoxy-beta-cyclodextrin (beta-CD-BR) bonded silica gels, which was used as the stationary phase of a packed capillary column for HPLC, was investigated concerning the retention behaviors of neutral cresol isomers. On the whole, the retention factors of the cresol isomers increased with an increase in the pH values of the mobile phase, although they were slightly smaller at pH 6.1 than at pH 4.7. An investigation on the retention variation using a van't Hoff plot revealed that the increase in the retention factor (k) at a higher pH region could be mainly attributed to the increase in DeltaS, while a partial decrease in k around pH 5 - 6 was caused by a decrease in the -DeltaH/T value. On the other hand, a measurement of the electroosmotic flow velocity under various pH of the mobile phase solutions revealed that the retention variations of the neutral cresol isomers were strongly correlated with the surface charge on the packing materials. The positive charge of secondary ammonium functional groups to bind beta-CD-BR inhibit the insertion of the cresol isomers into the cavity of beta-CD-BR while reducing the retention factor, whereas the negative charge of silanol group enhanced it through a local change in the mobile phase composition.

Chromatography, High Pressure Liquid↗