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Biomedical subjects

Ken Yamaguchi

Publications and source records attributed to Ken Yamaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2004

Sonography and MRI of the shoulder: comparison of patient satisfaction.

OBJECTIVE: MRI and sonography are both used to evaluate patients with painful shoulders. This study was conducted to compare patients' perceptions and satisfaction with both tests. SUBJECTS AND METHODS: One hundred eighteen patients with shoulder pain and a clinically suspected rotator cuff tear underwent both MRI and sonography and filled out satisfaction surveys after both tests. Patients were asked the following questions: Did the test cause pain? If it did, they were asked to grade the pain on a scale of 1-10 (1, minimal pain; 10, severe pain). Did the test take too long? Would they be willing to undergo the test again? How would they grade their overall satisfaction with the test (1, poor; 2, fair; 3, good; 4, very good; and 5, excellent)? Which test did they prefer if both were equally accurate? RESULTS: Sonography caused pain above the baseline in 39 patients, with an average pain score (mean +/- SD) of 5.4 +/- 2.3, and MRI caused pain above the baseline in 40 patients, with an average pain score of 6.1 +/- 2.7 (p = 0.36). Two patients thought the sonography examination took too long, and 28 patients though the MRI examination was too long (p < 0.001). The average satisfaction level for sonography was 4.3 +/- 0.7 and for MRI, 3.6 +/- 1.2 (p < 0.001). The satisfaction score was higher for sonography in 54 patients, higher for MRI in 13 patients, and the same for both in 50 patients (p < 0.001). All patients were willing to repeat the sonography, but 10 patients were unwilling to repeat the MRI (p = 0.002). Ninety-three patients preferred sonography, eight patients preferred MRI, and 17 patients had no preference (p < 0.001). CONCLUSION: Most patients with shoulder pain prefer sonography to MRI.

Female↗
PubMed2004

Sonography of the rotator cuff: analysis of interobserver variability.

OBJECTIVE: The purpose of our study was to determine the interobserver variability in the sonographic evaluation of the rotator cuff. SUBJECTS AND METHODS: Two radiologists independently scanned 61 patients with shoulder pain. Each radiologist categorized the rotator cuff as normal, partially torn, or fully torn. When a tear was present, the tendons involved were specified. All diagnoses were made prospectively without knowledge of the findings of the other radiologist. RESULTS: The radiologists were in full agreement in the categorization of 92% (56/61) of the patients. In four of the five discrepant cases, the disagreement was whether there was a full-thickness or a partial-thickness tear. The radiologists were in agreement concerning which tendons were involved in 80% (41/51) of the patients in whom a tear was detected by both observers. In all 10 discrepant cases, the disagreement was whether a tear involved both the supraspinatus and infraspinatus tendons or was isolated to one or the other of these tendons. CONCLUSION: The level of interobserver variability in the sonographic detection and characterization of rotator cuff tears is low.

Adolescent↗
PubMed2004

Detection and quantification of rotator cuff tears. Comparison of ultrasonographic, magnetic resonance imaging, and arthroscopic findings in seventy-one consecutive cases.

BACKGROUND: Although many investigators have evaluated the accuracy of ultrasonography and magnetic resonance imaging for the detection of full and partial-thickness rotator cuff tears, few have directly compared the two tests. The purpose of our study was to compare the accuracy of the two tests for detection and measurement of the size of rotator cuff tears, with arthroscopic findings used as the standard. METHODS: One hundred and twenty-four consecutive patients with shoulder pain were prospectively studied with ultrasonography and magnetic resonance imaging. Seventy-one had subsequent arthroscopy, and they formed the study group. The arthroscopic diagnosis was a full-thickness tear in forty-six patients, a partial-thickness tear in nineteen, and no tear in six. The presence or absence of a full or partial-thickness tear and the tear size as demonstrated by each imaging test and at the time of arthroscopy were recorded. The findings of the imaging tests and arthroscopy were then compared for each parameter. RESULTS: Ultrasonography correctly identified forty-five of the forty-six full-thickness tears and magnetic resonance imaging, all forty-six. Ultrasonography correctly identified thirteen of the nineteen partial-thickness rotator cuff tears and magnetic resonance imaging, twelve of the nineteen. The overall accuracy for both imaging tests was 87%. Ultrasonography correctly predicted the degree of retraction of 73% of the full-thickness tears and the length of 85% of the partial-thickness tears, and magnetic resonance imaging correctly predicted the retraction and length of 63% and 75%, respectively. Ultrasonography correctly predicted the width of 87% of the full-thickness tears and 54% of the partial-thickness tears, and magnetic resonance imaging correctly predicted the width of 80% and 75%, respectively. No significant differences between ultrasonography and magnetic resonance imaging were demonstrated (p > 0.05). CONCLUSIONS: Ultrasonography and magnetic resonance imaging had comparable accuracy for identifying and measuring the size of full-thickness and partial-thickness rotator cuff tears. When an investigator has comparable experience with both imaging tests, the decision regarding which test to perform for rotator cuff assessment does not need to be based on accuracy concerns. The choice can be based on other factors, such as the importance of ancillary clinical information (regarding lesions of the glenoid labrum, joint capsule, or surrounding muscle or bone), the presence of an implanted device, patient tolerance, and cost.

Adult↗
PubMed2004

Glenoid resurfacing in shoulder arthroplasty: indications and contraindications.

The indications for glenoid resurfacing are controversial. Advantages of glenoid resurfacing include decreased glenoid pain from metal-on-bone articulation, increased stability provided by the conforming glenoid component in the presence of asymmetric glenoid wear, and lateralization of the joint line providing for improved range of motion and strength. Proponents of hemiarthroplasty claim that function and pain relief are equivalent to glenoid resurfacing without the concomitant risk of glenoid loosening and loss of glenoid bone stock. In addition, hemiarthroplasty requires less surgical time and is less expensive than total shoulder arthroplasty. Total shoulder arthroplasty has been shown to be superior to hemiarthroplasty with regard to pain relief, range of motion, and function. Resurfacing of the glenoid has been indicated in older patients with primary osteoarthritis. In addition, patients with rheumatoid arthritis generally have better improvement in pain and function when treated with total shoulder arthroplasty than with hemiarthroplasty. Patients with severe rotator cuff disease, persistent instability, and lack of glenoid bone stock should be treated with hemiarthroplasty alone because glenoid resurfacing is associated with early loosening and failure. Patients with osteonecrosis isolated to the humeral head should be treated with hemiarthroplasty to preserve the native, congruent glenoid.

Arthritis↗
PubMed2004

Arthroscopic versus open treatment of anterior shoulder instability.

Open repair is the accepted mainstay of treatment for anterior shoulder instability, and consistently good clinical results have been reported in the literature. With the development of newer arthroscopic imbrication techniques, however, arthroscopy may eventually provide equivalent long-term efficacy.

Arthroscopy↗
PubMed2004

[Ectopic hormone-producing tumors--research and clinics].

Recent progress in endocrinology, cytokine research, and oncology has provided new information for further understanding of ectopic hormone-producing tumors. The mechanisms responsible for this morbidity need further investigations to clarify the neuroendocrine nature of tumor cells. Meanwhile, a common hormonal substance produced by a specific tumor could serve as a specific tumor marker for the tumor, as is the case of ProGRP for small cell lung cancer. The development of drugs for ectopic hormonal syndrome might be a good lesson of the molecular targeting for hormone signaling pathways. It is reasonable to postulate that the clinical entities covered by the term 'ectopic humoral syndrome' will be increasing.

Biomarkers, Tumor↗
PubMed2003

Allelic loss of DNA locus of the RET proto-oncogene in small cell lung cancer.

We analyzed all 21 exons of the RET proto-oncogene of paired genomic DNA from tumors and normal tissues in 12 small cell lung cancer (SCLC) patients for the presence of genetic alteration. Polymerase chain reaction single-strand conformation polymorphism analysis and direct sequencing revealed that heterozygosity of the RET proto-oncogene was lost in the tumor tissues of six patients out of eight informative SCLC patients, although point mutation was not evident in any tumors. These results suggest that a deletion of the chromosomal region including the RET proto-oncogene is involved in the pathogenesis of SCLC.

Carcinoma, Small Cell↗
PubMed2003

Structure and characterization of hamster IL-12 p35 and p40.

Complementary DNAs coding for two subunits of hamster interleukin-12 (IL-12), p35 and p40, were cloned from a hamster dendritic cell (DC) cDNA library. The cloning demonstrated that hamster IL-12 consisted of a p35 subunit with 216 amino acid (aa) residues and a p40 subunit with 327 aa. Structural comparison of hamster p35 and p40 at the protein level showed the highest homologies with each counterpart of sigmodon (hispid cotton rat). The gene expressions of hamster IL-12 p35 and p40 in bone marrow (BM) cells cultured in the presence of mouse granulocyte macrophage-colony-stimulating factor (mGM-CSF) and IL-4 were up-regulated during culture. Immunoblot analysis of 293 cells transfected with hamster p35 and p40 expression vectors suggested the presence of a covalently linked p35/p40 heterodimer. Furthermore, supernatant from the 293 cells transfected with both expression vectors induced the up-regulation of interferon-gamma (IFN-gamma) mRNA in hamster splenocytes, indicating that the p35/p40 heterodimer IL-12 protein present in the supernatant was functional. These results suggest that the vectors containing hamster IL-12 cDNA might be suitable tools for developing an immunotherapeutic approach against experimental cancer in a hamster model.

Amino Acid Sequence↗
PubMed2003

Accuracy of ultrasound imaging of the rotator cuff in shoulders that are painful postoperatively.

BACKGROUND: Evaluation of the rotator cuff in a shoulder that has been persistently painful postoperatively could be challenging. Magnetic resonance imaging has been the preferred imaging method, but accuracy rates have been lower for those shoulders than for shoulders that have not been operated on; also, magnetic resonance imaging is susceptible to suture anchor artifact. The purpose of this study was to evaluate the diagnostic accuracy of ultrasound for evaluating the rotator cuff in shoulders that are painful postoperatively. METHODS: The records of forty-four consecutive patients who had undergone both a high-resolution ultrasound examination and subsequent shoulder arthroscopy were retrospectively reviewed. Thirty-four patients underwent rotator cuff repair at the time of the arthroscopy, and ten had subacromial decompression or another procedure without cuff repair. The results of the ultrasound examination were compared with the intraoperative findings of the arthroscopic examination (the "gold standard"). RESULTS: Ultrasound led to a correct diagnosis for forty of the forty-four patients. Twenty-two recurrent rotator cuff tears and twenty-two intact rotator cuffs were found at surgery. Ultrasound correctly identified twenty of the twenty-two rotator cuff tears (true-positive results) and twenty of the twenty-two intact rotator cuffs (true-negative results). Two intact cuffs were identified as having a full-thickness tear (false-positive results), and two cuffs with a full-thickness rotator cuff tear were identified as being intact (false-negative results). The sensitivity and specificity of ultrasound for identifying rotator cuff integrity postoperatively were 91% and 86%, respectively. The accuracy was 89%. CONCLUSIONS: Ultrasound is a highly accurate imaging study for evaluating the integrity of the rotator cuff in shoulders that have undergone an operation. Its accuracy for operatively treated shoulders appears to be comparable with that previously reported for shoulders that had not been operated on.

Adult↗
PubMed2003

The posterior branch of the axillary nerve: an anatomic study.

BACKGROUND: Surgery on the posterior aspect of the shoulder has become accepted practice for a number of pathological conditions affecting the scapula and the glenohumeral joint. Despite this trend, the anatomy of the posterior branch of the axillary nerve has not been well characterized. The purpose of the present study was to determine the innervation pattern and surgical relationships of the posterior branch of the axillary nerve. METHODS: Nineteen fresh-frozen human cadaveric forequarter amputation specimens were dissected through a posterior approach. The location of the posterior branch of the axillary nerve and its anatomical relationships with surrounding structures were documented and measured with use of digital calipers. RESULTS: The posterior branch separated from the main anterior circumflex branch of the axillary nerve immediately anterior to the origin of the long head of the triceps muscle at the six o'clock position on the glenoid. It coursed posteriorly, adjacent to the inferior aspect of the glenoid rim for an average distance of 10 mm (range, 2 to 17 mm) before dividing into the superior-lateral brachial cutaneous nerve and the nerve to the teres minor. The nerve to the teres minor coursed medially along the posterior aspect of the inferior part of the glenoid rim for an average distance of 18 mm (range, 11 to 25 mm) before entering the muscle at its inferior border. The superior-lateral brachial cutaneous nerve coursed inferiorly, deep to the posterior aspect of the deltoid. It became superficial by passing around the medial border of the muscle at an average of 8.7 cm (range, 6.3 to 10.9 cm) inferior to the posterolateral corner of the acromion. CONCLUSIONS: The posterior branch of the axillary nerve has an intimate association with the inferior aspects of the glenoid and shoulder joint capsule, which may place it at particular risk during capsular plication or thermal shrinkage procedures. The superior-lateral brachial cutaneous nerve and the nerve to the teres minor always arise from the posterior branch. Thus, loss of sensation over the deltoid may indicate loss of teres minor function. The posterior aspect of the deltoid has a more consistent supply from the anterior branch of the axillary nerve, necessitating caution when performing a posterior deltoid-splitting approach to the shoulder.

Adult↗
PubMed2003

Sonography of the medial collateral ligament of the elbow: a study of cadavers and healthy adult male volunteers.

OBJECTIVE: We assessed the ability of high-resolution sonography to reveal the size and echogenicity of the anterior bundle of the normal medial collateral ligament of the elbow in cadavers and uninjured male volunteers. MATERIALS AND METHODS: The anterior bundle of the medial collateral ligament in five cadaveric elbows was imaged and injected with contrast material by experienced musculoskeletal radiologists using a 12-MHz linear array transducer. Immediate ligament dissection was performed. The bilateral ligaments in 30 healthy 21- to 34-year-old male volunteers were imaged with gravitational stress. Of these, five randomly selected subjects also received approximately 5 lb (11.3 kg) of applied stress. RESULTS: Contrast material was injected directly into all five cadaveric ligaments. The anterior bundle of the medial collateral ligament in all 30 asymptomatic male volunteers was hyperechoic in comparison with surrounding muscle and had a fibrillar pattern and fanlike shape. Its mean dimensions were 2.6 +/- 0.31 x 2.2 +/- 0.47 x 4.0 +/- 0.88 mm on the right and 2.6 +/- 0.36 x 2.1 +/- 0.42 x 4.0 +/- 0.86 mm on the left, in longitudinal short, transverse short, and transverse long axes, respectively. Differences in ligament measurements in sidedness, stress application, and hand dominance did not approach statistical (Bonferroni corrected, p > 0.01) or clinical (all differences, <0.2 mm) significance. CONCLUSION: Radiologists can accurately use sonography to identify and measure the size of the anterior bundle of the normal medial collateral ligament of the elbow. These baseline parameters for the normal ligament may prove useful when evaluating the injured ligament.

Adult↗
PubMed2003

Transitioning to arthroscopic rotator cuff repair: the pros and cons.

There has been much recent enthusiasm regarding complete arthroscopic rotator cuff repair, and it is becoming apparent that, for many, this newer technique may be a preferable alternative to the more traditional mini-open rotator cuff repair. Several short-term studies have demonstrated that complete arthroscopic repair has excellent results comparable with those of mini-open repair, which is also an excellent technique. The choice of which procedure may be better for an individual patient or surgeon can be based on a variety of considerations, including the patient's expectations, the pathoanatomy of the cuff, and the surgical experience of the surgeon. The relative merits and disadvantages of arthroscopic rotator cuff repair are discussed on the basis of those considerations. When a surgeon is deciding which procedure to perform, it is important that the basic principles of rotator cuff repair not be compromised and that he or she perform the procedure that is most reproducible given his or her level of experience; however, for those who are now utilizing miniopen repair, arthroscopic repair may have important advantages and may be worth pursuing in the future. If a surgeon chooses to obtain the skills necessary to perform a complete arthroscopic repair, performance of the mini-open procedure offers an excellent opportunity to make an orderly transition.

Arthroscopy↗
PubMed2002

Antitumor effects induced by dendritic cell-based immunotherapy against established pancreatic cancer in hamsters.

Because the prognosis of patients with pancreatic cancer is very poor, development of a novel approach for treatment of this disease is vital. In the present study, we investigated the effect of dendritic cell (DC)-based immunotherapy against established syngeneic hamster pancreatic cancer named HPD1NR. Hamster enriched DCs were prepared from bone marrow (BM) by a culture for 7 days in the presence of mouse GM-CSF and mouse IL-4, and characterized by the expression of specific DC markers (DEC205, DC-SIGN) mRNA using in situ hybridization (ISH). DCs pulsed with tumor lysate and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methylsulfate (DOTAP) or DCs alone were injected s.c. weekly into HPD1NR-bearing hamsters three times. Tumor growth was significantly inhibited by 82% in hamsters treated with tumor lysate and DOTAP-pulsed DCs when compared with the PBS vehicle-treated group. These findings suggest that DC-based immunotherapy may be a useful approach for the treatment of pancreatic cancers.

Animals↗
PubMed2002

Peptidomics-based approach reveals the secretion of the 29-residue COOH-terminal fragment of the putative tumor suppressor protein DMBT1 from pancreatic adenocarcinoma cell lines.

Deleted in malignant brain tumors 1 is a putative tumor suppressor protein in brain, lung, esophageal,gastric, and colorectal cancer. Here we report the mass spectrometric identification of a 3335 Da peptide, which was found in serum-free conditioned medium from 5 of 15 pancreatic adenocarcinoma cell lines but not from 35 carcinoma cell lines and 2 nonmalignant pancreatic duct cell lines. The peptide was the 29 COOH-terminal amino acids from deleted in malignant brain tumors 1. It is suggested that the peptide is generated inside the cells by limited proteolysis and extracellularly secreted. Our peptidomics-based approach will help screen candidate marker peptides for a particular type of cancer.

Adenocarcinoma↗
PubMed2002

Identification of HLA-A24-restricted CTL epitope encoded by the matrix protein pp65 of human cytomegalovirus.

The activation of a specific cellular immune response against human cytomegalovirus (CMV) is an important key factor to solving CMV infection after bone marrow transplantation (BMT). In the present study, our purpose was to identify the HLA-A24-restricted cytotoxic T cell (CTL) epitope from the CMV immunogenic matrix protein pp65. We selected five CMV pp65 peptides with HLA-A24 binding motif from the HLA peptide binding predictions web site. Peptide binding assay was performed using biotinylated HLA-A24-restricted MAGE-1 peptide as a reference peptide and transporter associated with antigen processing (TAP)-deficient T2-A24 cells expressing high level of HLA-A24 protein as target cells. After co-incubation of biotinylated MAGE-1 and titrated amounts of competitor peptides with T2-A24 cells, the binding of each peptide was analyzed on a flow cytometer. Peptide binding assay showed that three out of five peptides derived from CMV pp65 bound to T2-A24 cells with various affinity levels. CTL induction assay using peptide-pulsed DC derived from eight HLA-A24(+) donors revealed that the peptide (QYDPVAALF) with the highest affinity was able to elicit potent CTLs which killed peptide-pulsed TISI cells. These CTLs were found to show the killing activity against human fibroblast cells transduced with both HLA-A*2402 and CMV pp65 cDNAs, and CMV-infected HLA-A24(+) fibroblast cells. These results suggested that the peptide (QYDPVAALF) is one of HLA-A24-restricted CTL epitope derived from CMV pp65 protein and may be of therapeutic value in peptide-based vaccines against CMV infection in BMT patients.

Antibodies, Monoclonal↗
PubMed2002

Hamster DEC-205, its primary structure, tissue and cellular distribution.

DEC-205, a putative antigen uptake receptor, belongs to a family of transmembrane C-type lectins. This molecule is known to be one of the most authentic markers for the lineage of dendritic cells. In the present study, we determined the primary structure, tissue distribution and cellular localization of hamster DEC-205. The multi-domain structure of mouse and human DEC-205 was completely conserved in hamster with the overall identity of approximately 80%. DEC-205 transcripts were detected in the thymus and bone marrow cells cultured in the presence of mouse granulocyte macrophage colony-stimulating factor and interleukin-4 in which the DEC-205 expression was up-regulated in the course of cultures. Hamster DEC-205 was mainly detected on cell membrane and shown to mediate the uptake of flourescein isothiocyanate-conjugated ovalbumin. DEC-205 is a highly conserved molecule across the species suggesting its fundamental role in the immune system.

Amino Acid Sequence↗
PubMed2002

Menin, the multiple endocrine neoplasia type 1 gene product, exhibits GTP-hydrolyzing activity in the presence of the tumor metastasis suppressor nm23.

MEN1, the gene responsible for multiple endocrine neoplasia type 1, is a tumor suppressor gene that encodes a protein called menin, of unknown function with no homology to any known protein. Here we demonstrate that menin interacts with a putative tumor metastasis suppressor nm23H1/nucleoside diphosphate (NDP) kinase A in mammalian cells. Given the roles of nm23 as a multi-functional protein, we searched for the possible function of menin. Menin has no effect on the known activities of nm23; that is, nucleoside diphosphate kinase, protein kinase, or GTPase-activating protein for Ras-related GTPase Rad. However, we found that menin hydrolyzes GTP to GDP efficiently in the presence of nm23, whereas nm23 or menin alone shows little or no detectable GTPase activity. Furthermore, menin contains sequence motifs similar to those found in all known GTPases or GTP-binding proteins and shows low affinity but specific binding to GTP/GDP. These results suggest that menin is an atypical GTPase stimulated by nm23.

Amino Acid Motifs↗