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Biomedical subjects

A Kobayashi

Publications and source records attributed to A Kobayashi.

At least 19 recordsLinked to original sources
PubMed2006

Vortex dynamics and the Fulde-Ferrell-Larkin-Ovchinnikov state in a magnetic-field-induced organic superconductor.

Under special conditions, a superconducting state where the order parameter oscillates in real space, the so-called FFLO state, is theoretically predicted to exist near the upper critical field, as first proposed by Fulde and Ferrell, and Larkin and Ovchinnikov. We report systematic measurements of the interlayer resistance in high magnetic fields to 45 T in the two-dimensional magnetic-field-induced organic superconductor lambda-(BETS)2FeCl4, where BETS is bis(ethylenedithio)tetraselenafulvalene. The resistance is found to show characteristic dip structures in the superconducting state. The results are consistent with pinning interactions between the vortices penetrating the insulating layers and the order parameter of the FFLO state. This gives strong evidence for an oscillating order parameter in real space.

Journal Article↗
PubMed2006

Morphological and histopathological changes in tongues of experimentally developed acromegaly-like rats.

An acromegaly-like rat model recently developed by exogenous administration of insulin-like growth factor I (IGF-I) was used to investigate morphological and histopathological tongue changes and clarify whether the changes were reversible. Human recombinant IGF-I (640 microg/day) was continuously subcutaneously infused into ten-week-old male rats for four weeks (IGF-I group; n = 6). Control sham-operated animals were injected saline alone (control group; n = 6). Rats were sacrificed immediately on ending administration at the age of fourteen weeks. Another 12 rats (6 from each group) were housed for an additional four weeks after administration ended. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. Tongue weights significantly increased with histopathological changes present (increases in the muscle-bundle width, spaces between muscle-bundles and epithelium thickness) in the IGF-I group compared to control rats. Tongue size returned to control levels after discontinuation of IGF-I administration. These findings suggest that the characteristic tongue enlargement was developed experimentally in our acromegaly-like rat model, and that such morphological and histopathological tongue changes are reversible on normalization of circulating IGF-I levels.

Acromegaly↗
PubMed2006

Comparison of allergenicity and allergens between fish white and dark muscles.

BACKGROUND: Fish is one of the most frequent causes of immunoglobulin E (IgE)-mediated food allergy. Although the fish dark muscle is often ingested with the white muscle, no information about its allergenicity and allergens is available. METHODS: Heated extracts were prepared from both white and dark muscles of five species of fish and examined for reactivity with IgE in fish-allergic patients by enzyme-linked immunosorbent assay (ELISA) and for allergens by immunoblotting. Cloning of cDNAs encoding parvalbumins was performed by rapid amplification cDNA ends. Parvalbumin contents in both white and dark muscles were determined by ELISA using antiserum against mackerel parvalbumin. RESULTS: Patient sera were less reactive to the heated extract from the dark muscle than to that from the white muscle. A prominent IgE-reactive protein of 12 kDa, which was detected in both white and dark muscles, was identified as parvalbumin. Molecular cloning experiments revealed that the same parvalbumin molecule is contained in both white and dark muscles of either horse mackerel or Pacific mackerel. Parvalbumin contents were four to eight times lower in the dark muscle than in the white muscle. CONCLUSIONS: The fish dark muscle is less allergenic than the white muscle, because the same allergen molecule (parvalbumin) is contained at much lower levels in the dark muscle than in the white muscle. Thus, the dark muscle is less implicated in fish allergy than the white muscle.

Allergens↗
PubMed2006

Eligibility of stroke units in Poland for administration of intravenous thrombolysis.

Systemic thrombolysis treatment was approved in Poland in 2003 and should be performed in specialist stroke units (SU). We performed a survey to determine stroke service preparedness for thrombolysis treatment in Poland. We sent a questionnaire evaluating the neurological departments in Poland, where stroke patients are treated. We divided them into four categories: (i) class A SU (fulfilling criteria of the National Program for Stroke Prevention and Therapy and European Stroke Initiative guidelines), (ii) class B (conditionally fulfilling criteria), (iii) class C (not fulfilling criteria), and (iv) departments without SU. Only class A units are eligible for implementing thrombolysis. We obtained response from 194 of 222 (87.4%) departments; 90 (46.4%) declared having an SU. According to criteria, 20 class A, 56 class B, 14 class C. During one year, 71 208 patients were admitted to hospitals; 69,982 (98.2%) to neurological departments. A total of 10,959 (15.4%) were treated in class A SU, 23,650 (33.2%) in class B, 5153 (7.2%) in class C, whereas 30,220 (42.4%) in neurological departments without SU. Our survey showed that only 15.4% stroke patients in Poland are admitted to high-quality SU, where thrombolysis may potentially be administered. Improvement of SU quality in Poland is necessary for wide implementation of new methods of stroke therapy.

Disability Evaluation↗
PubMed2006

Evaluation of the flexion gap by axial radiography of the distal femur.

The shape of the flexion gap in 20 normal knees was evaluated by axial radiography of the distal femur, and the results compared with those obtained in a previous study by MRI. The observed asymmetry was reduced by 29% using radiography, with a mean value of 3.6 degrees (1.5 degrees to 6.3 degrees) compared with that obtained by MRI of 5.1 degrees (2.6 degrees to 9.5 degrees), a mean discrepancy of 1.49 degrees. The results obtained by radiography and MRI showed a strong correlation (r = 0.78). Axial radiography is acceptable for the evaluation of the flexion gap and is less expensive and more comfortable to perform than MRI. Additionally, no metallic artefact occurs when the radiological method is used for assessment after arthroplasty.

Adolescent↗
PubMed2006

[Off-pump atrial septectomy in a small neonate].

We report a surgical technique for off-pump atrial septectomy using a Rongeur forceps in the case of a newborn infant weighing less than 2,000 grams. The 6-day-old patient suffered from hypoplastic left heart syndrome with a restrictive interatrial communication. A purse-string suture was placed on the right atrium. A hand-made dull-tipped cannula was inserted into the right atrium through the suture to probe the interatrial communication. Monitoring the pressure at the tip of cannula, we could clearly determine when the cannula tip entered the left atrium. Then, a Rongeur forceps was inserted instead of the cannula, and used to bite into the interatrial septum. It was removed slowly together with the resected atrial specimen. In this manner, an atrial septectomy can be performed without cardiopulmonary bypass; this is far safer and easier than other procedures, such as the Blalock-Hanlon technique. This method can be performed in a small neonate as well as an older infant in whom balloon atrial septostomy is difficult.

Cardiac Surgical Procedures↗
PubMed2005

Detection of cerebral oxyhaemoglobin changes during vestibular Coriolis cross-coupling stimulation using near infrared spectroscopy.

Near infrared spectroscopy (NIRS) has been successful in monitoring cerebral haemodynamics when the subject is immobilized during surgery, and when there is a drastic depletion of blood from the cerebral cortex during positive acceleration. In this study, we monitored subtle changes of cerebral oxygen level using NIRS during vestibular stimulation. For the control conditions, cerebral oxygen status was monitored in six stationary subjects sitting upright, and while they executed head movements in the pitch axis with eyes opened and eyes closed. The experimental conditions involved the subjects making a head movement which required a 45 degrees pitch-down followed by a return to upright head movements 12 s later during yaw rotation (Coriolis cross coupling) at 10 and 20 rotations per minute (rpm) in a random order. Oxyhaemoglobin (O(2)Hb), deoxyhaemoglobin (HHb) and total haemoglobin levels were recorded every 0.5 s from both the parietal and the occipital lobe simultaneously. A significant rotation effect was observed in total Hb level changes from baseline in both regions. Occipital O(2)Hb increased significantly after the head movement with eyes opened at 20 rpm. Our findings appear to be consistent with previous vestibular studies that significant changes in brain blood flow occur during caloric stimulation. NIRS can be used to monitor discrete cortical blood flow changes resulting from vestibular and other forms of stimulation.

Adult↗
PubMed2005

Phase I trial of oral S-1 combined with gemcitabine in metastatic pancreatic cancer.

The objective of this study was to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of S-1, an oral fluorouracil derivative, combined with gemcitabine, the current standard treatment for advanced pancreatic cancer (APC). The subjects were histopathologically proven APC patients with distant metastasis. S-1 was administered orally twice daily each day for 14 days and gemcitabine on days 8 and 15 of each cycle, and this was repeated every 21 days. Doses of each drug were planned as follows: level 1: 800/60, level 2a: 800/80, level 2b: 1000/60, level 3: 1000/80 (gemcitabine (mg m(-2))/S-1 (mg m(-2) day(-1))). In all, 21 patients with APC were enrolled. The main grade 3-4 toxicities observed during first cycle were neutropenia (33%), anaemia (10%), thrombocytopenia (14%) and anorexia (10%). There were no DLT observed in level 1. Three of six patients in level 2a had DLT and this level was considered the MTD. In all, 12 patients in level 2b had no DLT and this level was selected as the recommended dose. Applicable responses were one complete response and nine partial responses (48%). As toxicities were well tolerated and antitumour activities seem to be promising, this combination can be recommended for further phase II studies with APC.

Administration, Oral↗
PubMed2005

Intraoral minor salivary gland tumors: a clinicopathological study of 82 cases.

We present a retrospective study of 82 patients with intraoral minor salivary gland tumors which were diagnosed from 1979 to 2003 in Gifu University Hospital. The histological diagnoses were reevaluated according to the 1991 WHO classification. A total of 82 tumors, consisting of 55 benign and 27 malignant tumors, were found in 28 male and 54 female Japanese patients; the male-to-female ratio was 1:1.9. The mean age of the patients was 51.4+/-18.1 years. The tumors affected the palate (n = 64), the buccal region (n = 10), the upper lip (n = 6), the floor of the mouth (n = 1), and the retromolar region (n = 1). Histologically, the tumors were classified as pleomorphic adenoma (n = 54), papillary cystadenoma (n = 1), adenoid cystic carcinoma (n = 10), mucoepidermoid carcinoma (n = 8), acinic cell carcinoma (n = 3), adenocarcinoma (n = 2), basal cell adenocarcinoma (n = 1), papillary cystadenocarcinoma (n = 1), and carcinoma in pleomorphic adenoma (n = 2). From the results of the present study and review of the literature, it is suggested that the minor salivary gland tumors in Japan may be characterized by a higher incidence of benign tumors, especially of pleomorphic adenoma; a more marked tendency for female predominance; a higher incidence of palatal involvement; and a rarer occurrence of polymorphous low grade adenocarcinoma, in comparison with those reported in the literature from outside of Japan.

Adenocarcinoma↗
PubMed2004

Insulin-like growth factor-I stimulates acromegaly-like specific mandibular enlargement in rats.

To help us investigate the time course of mandibular enlargement in acromegaly or acrogiantism to determine the most suitable period for occlusal treatment in this disease, our aim was to develop a rat model of acromegaly (acrogiantism). In this study, prominent mandibular enlargement was induced by continuous subcutaneous infusion of human recombinant insulin-like growth factor-I (IGF-I) (640 microg/day) in 10-week-old male rats for 4 weeks (n = 6); the control sham-operated group was injected with saline alone (n = 6). Circulating human IGF-I was clearly detectable in the IGF-I group during the four-week administration period, while endogenous rat IGF-I levels decreased. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. The length of every bone examined (mandible, maxilla, and femur) showed a significant increase compared to control rats, especially the mandible. Although the mandible did not continue to grow after discontinuation of IGF-I administration, it did not return to control size, unlike the maxilla and femur, and disharmonious jaw size (between maxilla and mandible) persisted even after circulating IGF-I levels normalized. These findings in our rat model suggest that mandibular occlusal treatment should only be considered for acromegalic (acrogiantic) patients after serum IGF-I levels have normalized and bone growth has ceased.

Acromegaly↗
PubMed2004

The flexion gap in normal knees. An MRI study.

Varus and valgus joint laxity of the normal living knee in flexion was assessed using MRI. Twenty knees were flexed to 90 degrees and were imaged in neutral and under a varus-valgus stress in an open MRI system. The configuration of the tibiofemoral joint gap was studied in slices which crossed the epicondyles of the femur. When a varus stress was applied, the lateral joint gap opened by 6.7 +/- 1.9 mm (mean +/- SD; 2.1 to 9.2) whereas the medial joint gap opened by only by a mean of 2.1 +/- 1.1 mm (0.2 to 4.2). These discrepancies indicate that the tibiofemoral flexion gap in the normal knee is not rectangular and that the lateral joint gap is significantly lax. These results may be useful for adequate soft-tissue balancing and bone resection in total knee arthroplasty and reconstruction surgery on ligaments.

Adolescent↗
PubMed2003

A primary retroperitoneal serous cystadenocarcinoma with clinically aggressive behavior.

CASE REPORT: We describe a 44-year-old woman with a primary retroperitoneal serous cystadenocarcinoma as the fourth report in the world literature. A contrast-enhanced computed tomographic scan of the abdomen demonstrated a mass with enhanced solid mural nodules and septa in the left retroperitoneum. Serum CA19-9 was elevated at 181 U/ml. The patient underwent a complete resection of the retroperitoneal tumor with a partial resection of the psoas major muscle and its fascia. Pathological examination showed a well-differentiated papillary serous cystadenocarcinoma of ovarian type and locoregional lymph node metastases. Seven months after surgery, the patient developed a pelvic recurrence, and underwent a total hysterectomy, a left salpingo-oophorectomy and a resection of the metastatic mesenteric mass. Two months after the second surgery, serum CA19-9 and CA125 increased to 1,114 U/ml and 218 U/ml, respectively. A solitary liver metastasis was confirmed on a computed tomographic scan. The patient is now being treated with weekly docetaxel and carboplatin. CONCLUSION: The present case illustrates the clinically aggressive nature of a primary retroperitoneal serous cystadenocarcinoma.

Adult↗
PubMed2003

Muscle performance after anterior cruciate ligament reconstruction.

We measured muscle strength in 36 patients after anterior cruciate ligament (ACL) reconstruction with autogenous bone-patellar tendon-bone graft. Quadriceps and hamstring isokinetic strength was assessed during concentric contraction at 60 and 180 degrees /s and was measured at 1, 6, 12 and 24 months postoperatively. At 24 months quadriceps muscle strength had recovered to approximately 90% of the level of the uninvolved side, both at 60 and 180 degrees /s. In contrast, hamstring muscle strength had already recovered to approximately 90% at 6 months. Age, gender, activity level, and anterior tibial laxity did not affect the muscle performance. However, the recovery of muscle strength was delayed in patients with anterior knee pain.

Adolescent↗
PubMed2003

Analysis of long-chain polyprenols using supercritical fluid chromatography and matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

The separation of long-chain polyprenols was successfully achieved using supercritical fluid chromatography (SFC). Each 100-mer greater component was separated using tetrahydrofuran as a mobile phase modifier. The molecular mass distributions derived from SFC analyses agreed with the results of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analyses. The number-average molecular mass calculated by MALDI-TOF-MS data were also in accord with the results of quantitative 1H-NMR analysis of terminal groups. A combination of SFC and MALDI-TOF-MS analyses is a powerful tool for the elucidation of the complicated structures of natural polyprenols.

Chromatography, Supercritical Fluid↗
PubMed2003

Arthroscopic management of tibial plateau fractures--comparison with open reduction method.

BACKGROUND: Arthroscopic treatment of tibial plateau fractures were compared with open traditional methods retrospectively. METHODS: Twenty-eight patients were included in this comparative study based on fracture patterns and divided into two groups. Using Schatzker's classification system, patients with type II (split depression), type III (isolated depression) fractures, or other fracture types were included. Nineteen of these patients were treated by arthroscopically assisted management (group S), and the remaining 9 underwent the conventional open method (group O). RESULTS: There was no significant difference between both groups in terms of duration of operation, postoperative flexion, and clinical results. In group S, however, the postoperative rehabilitation was easier and faster (the time to obtain 120 degrees of flexion was 4.6+/-3.9 weeks in group S, 9.1+/-8.6 weeks in group O). Furthermore, 16 of 19 patients (84%) in group S obtained an anatomical reduction (defined as <2 mm of residual displacement after surgery), whereas in group O, only 5 of 9 patients (55%) had an anatomical reduction. Also, accurate diagnosis and treatment of any associated joint pathology was possible with arthroscopic management. CONCLUSION: The arthroscopic procedure is recommended in selected tibial plateau fractures.

Adolescent↗
PubMed2003

Temporary amniotic membrane patching for acute chemical burns.

PURPOSE: To describe the surgical technique, and its usefulness, of temporary amniotic membrane patching (AMP) in the acute phase of ocular chemical injury. METHODS: Temporary AMP with modification in suture placement was performed on five eyes of five consecutive patients inflicted with acute chemical injury having a greater than grade II injury by the Roper-Hall classification. RESULTS: All patients reported herein presented with a large epithelial defect on the cornea and conjunctiva. Case 3 was classified as grade III while the other four cases were classified as grade II. The causative chemical agents were anhydrous acetic acid in Case 1, calcium oxide in Case 2, sodium hydroxide in Case 3, sodium silicate in Case 4, and sulphuric acid in Case 5. All cases experienced rapid relief of pain after AMP. Epithelialization of the cornea with improvement of visual acuity was observed in all cases when the amniotic membrane was removed within 2 weeks after surgery. During the mean follow-up of 19.6 months, the ocular surface remained stable and no cicatricial complications were noted. CONCLUSIONS: These results suggest that immediate AMP is quite useful for managing moderately severe acute ocular chemical injury by facilitating rapid epithelialization and pain relief, and securing ocular surface integrity.

Acute Disease↗