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Biomedical subjects

M Hara

Publications and source records attributed to M Hara.

At least 415 records · Page 23Linked to original sources
PubMed1997

Stabilization of Liposomes Attached to Polymer Surfaces Having Phosphorylcholine Groups

The adsorption state of liposomes on a polymer surface containing a phosphorylcholine group, that is, omega-methacryloyloxyalkyl phosphorylcholine (MAPC) polymer, was evaluated using a quartz crystal microbalance and an atomic force microscope. After a quartz crystal resonator coated with the MAPC polymer or poly[2-hydroxyethyl methacrylate (HEMA)] was equilibrated with distilled water, the quartz crystal was contacted with a dipalmitoylphosphatidylcholine (DPPC) liposomal suspension. The resonance frequency change during liposome adsorption on the poly(HEMA)-coated resonator was larger than that on the MAPC polymer-coated resonator. The temperature response based on the phase transition of adsorbed DPPC liposomes, that is, the liquid crystalline state to gel state, on the MAPC polymer-coated resonator was more sensitive than that on the poly(HEMA)-coated resonator. Moreover, when the DPPC liposomes adsorbed on the polymer surfaces were disintegrated with a nonionic surfactant, it took longer for the frequency to return to the initial value of the poly(HEMA)-coated resonator than to that of the MAPC polymer-coated resonator. According to atomic force microscopic observation of the polymer surface after treatment with the liposomal suspension, the DPPC liposomes adsorbed on the MAPC polymers maintained their spherical shape well. We conclude that DPPC liposomes adsorbed on the poly(HEMA) surface can penetrate a hydrated layer and its ordered structure. On the other hand, DPPC liposomes may adsorb to the MAPC polymer surface without change in their original structure. Copyright 1997Academic Press

Journal Article↗
PubMed1997

Elevation of serum creatine kinase during treatment with antithyroid drugs in patients with hyperthyroidism due to Graves disease. A novel side effect of antithyroid drugs.

We describe 4 patients with Graves disease who had abnormal increases of serum creatine kinase (CK) concentrations during treatment with antithyroid medications. Three of the patients experienced myalgia and muscle cramps. All of the patients manifested an increase in serum CK levels 1 to 3 months after the administration of antithyroid drugs. Thyrotropin concentrations and cardiac systolic time indexes during the elevation of serum CK concentrations were not consistent with hypothyroidism. The mechanisms are not obvious, but it is likely that the rapid decrease of thyroid hormones in tissues may temporarily cause hypothyroid states, resulting in alterations in CK concentrations. It is suggested that hasty correction of thyrotoxicosis should be avoided in susceptible patients, unless the thyrotoxic conditions are critical.

Adult↗
PubMed1997

A new semi-automated chromosome analysis system for in vitro chromosomal aberration tests.

We have evaluated a new semi-automated chromosome analysis system, employing the Magiscan human metaphase finder, for in vitro chromosomal aberration tests. The metaphases on a slide are recognized using the main system, a metaphase finder, and their stage coordinates are transferred to the satellite system, a computerized microscope with a motorized stage, by way of a diskette. In the satellite system, a researcher analyzes one metaphase after another at high power (100 x objective) without changing the objective. The effectiveness of the system, in comparison with the manual metaphase finding and analysis, was confirmed in in vitro chromosomal aberration tests using cultured Chinese hamster cells. Structural or numerical aberrations in the cells did not affect the metaphase findings. The system reduces the time for chromosome analysis by a factor of about 4. Moreover, the system provides perfect reproducibility for analyzing procedure. It is concluded that this semi-automated system is useful in in vitro chromosomal aberration tests.

Animals↗
PubMed1997

A method to provide magnet-free long straight sections in low-emittance synchrotron radiation sources.

In a low-emittance synchrotron radiation source it is difficult to provide magnet-free long straight sections (MLSSs) a few tens of metres long because introducing MLSSs to the radiation source causes symmetry breaking and markedly reduces dynamic stability. To overcome this difficulty and realize MLSSs in such a ring, a method of building MLSSs is proposed starting from the stable lattice with high symmetry and proceeding via a transient lattice.

Journal Article↗
PubMed1997

Experimental studies of stereotactic laser balloon hyperthermic treatment.

BACKGROUND AND OBJECTIVE: The hyperthermic treatment of small malignant brain tumors in basal ganglia and other eloquent cortical areas was investigated with a stereotactic Nd:YAG laser balloon unit. STUDY DESIGN/MATERIALS AND METHODS: An Ultra Line fiber (Heraeus Laser Sonics, CA) was inserted into a 6 F silicone balloon catheter, which caused the laser beam to be directed 80 degrees laterally. The balloon was inflated with physiologic saline to make the tumor tissue surrounding the laser fiber hypoxic. The hypoxia enhances the thermal effect on the tumor. The laser power was set at 5 watts (W) and a computer, programmed with specific parameters using feedback control was used to maintain the tissue 10 mm distant from the laser fiber at a temperature of 45 degrees C. Forty five minutes of hyperthermic treatment was applied to an implanted subcutaneous glioma in a rat. RESULTS/CONCLUSION: The thermally induced damaged in the tumor appeared as a fan-shape lesion extending at a 100 degrees angle from the laser beam axis. The entire tumor could be treated by rotating the laser fiber in the balloon catheter.

Animals↗
PubMed1997

Characterization, guanosine 5'-O-(3-thiotriphosphate) modulation, daily variation, and localization of melatonin-binding sites in the catfish (Silurus asotus) brain.

Characteristics, guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) modulation, daily variation, and localization of melatonin-binding sites in the brain of a nocturnal teleost, the catfish Silurus asotus, were studied by radioreceptor assay using 2-[125I]iodomelatonin as the radioligand. The specific binding was rapid, stable, saturable, and reversible. The radioligand binds to a single class of receptor site with an affinity (Kd) of 30.7 +/- 7.3 pM and total binding capacity (Bmax) of 9.76 +/- 0.79 fmol/mg protein (mean +/- SE, n = 5). The binding sites were highly specific for 2-iodomelatonin and melatonin. The specificity was almost identical to that of functional melatonin receptors in the dermal and epidermal melanophores in this species and that of ML-1 subtype melatonin receptors in vertebrates, including melatonin-binding sites in the goldfish brain. GTPgammaS treatment altered both the Kd and Bmax values, indicating that melatonin-binding sites in the catfish brain are coupled to G protein. The Bmax values exhibited no daily variation under light-dark cycles of 12 hr light:12 hr dark whereas plasma melatonin levels and Kd fluctuated in a rhythmic fashion. The density of melatonin-binding sites in discrete brain areas was determined to be highest in optic tectum-thalamus and hypothalamus, intermediate in telencephalon, cerebellum, and medulla oblongata, and lowest in olfactory bulbs. These results suggest that melatonin secreted from the pineal organ and/or retina plays neuromodulatory roles in the catfish brain via G protein-coupled melatonin receptors. Characteristics of melatonin receptors seem to be highly conserved during evolution, although the density of melatonin receptors is not regulated by melatonin itself in this species.

Animals↗
PubMed1997

Metastasis of rectal cancer to lymph nodes and tissues around the autonomic nerves spared for urinary and sexual function.

PURPOSE: To clarify the indications for autonomic nerve-sparing operations for rectal cancer, the presence of lymph nodes and metastasis in the tissue around the autonomic nerve were examined in 28 rectal cancer patients. These were staged as pT2 in 8 patients, pT3 in 19 patients, and pT4 in 1 patient histopathologically. METHODS: The specimens of the autonomic nerve including the inferior mesenteric plexus, preaortic plexus, superior hypogastric plexus, hypogastric nerve, and pelvic plexus were removed with radical abdominopelvic lymphadenectomy after the autonomic nerve-sparing rectal cancer operation. RESULTS: In the tissue around the autonomic nerve, lymph nodes were 11.2 +/- 9.6 in number and 2.6 +/- 2.4 mm in size (mean +/- standard deviation). The frequency of presence of lymph nodes was higher and the number of lymph nodes was larger in the inferior mesenteric plexus (70.4 percent; 3.6) and the preaortic plexus (66.7 percent; 2.1) than in the left and right pelvic plexuses (39.1 percent, 1; 36 percent, 1). Metastasis to the lymph nodes or lymphatic permeation in the tissue around the autonomic nerve were observed in four cases (14.3 percent) of lower rectal cancer, consisting of three with Stage III cancer (pT3, pN1-3, and M0) and one with Stage IV cancer (pT4, pN1, and pM1 (HEP)). CONCLUSION: Radical rectal excision that includes lymph nodes and adjacent tissue around the autonomic nerves may result in metastatic tumor removal that would otherwise be left in situ with nerve-sparing techniques for advanced rectal cancer in Stage III.

Autonomic Pathways↗
PubMed1997

An assessment of the anatomical relationship between the pelvic plexus and the rectal wall to determine the indications for its preservation in surgery for rectal cancer.

Preservation of the pelvic plexus in surgery for rectal cancer could shorten the distance between the cancer and the lateral resection margin, whereby the curability of the operation may be reduced. To clarify the indications for preserving the pelvic plexus in such surgery, the relationship of the pelvic plexus to the rectum and rectal cancer was investigated anatomically in 12 autopsied specimens and 12 surgical specimens. The rectum and anus were dissected with all the pelvic organs from autopsied cadavers and transverse sections were prepared at 10-mm intervals after fixation. The location of the pelvic plexus was then measured on the tissue preparations, and compared to that of surgical specimens from rectal cancers with concurrent resection of the pelvic plexus. The pelvic plexus was located from 3.3 +/- 1.2 cm above to 2.3 +/- 1.9 cm below the peritoneal reflection in the autopsied specimens. The average distances between the muscularis propria and the pelvic plexus in the autopsied specimens and surgical specimens were 8.3 +/- 3.5 mm and 14.7 +/- 4.5 mm, respectively, showing a significant difference (P < 0.05). Pelvic plexuses were located about 10 mm from the outer margin of rectal muscularis propria. These findings indicate that concurrent resection of the pelvic plexus may be required to secure sufficient surgical clearance in pT3 rectal cancers, especially those invading deeply beyond the muscularis propria (a2).

Cadaver↗
PubMed1997

Visceral organ involvement and extracellular matrix changes in beta 2-microglobulin amyloidosis--a comparative study with systemic AA and AL amyloidosis.

Patterns of amyloid distribution and extracellular matrix changes in the heart and gastrointestinal tract were compared among beta 2-microglobulin (B2M), AA (secondary), and AL (primary and multiple myeloma-associated) amyloidosis cases. B2M amyloid was found to be mainly distributed in the small arterioles, venules, endocardium and muscularis propria of these organs, the deposits characteristically forming subendothelial nodular lesions in the vessels. A marked increase of chondroitin sulfate (CS) was consistently detected in B2M amyloid. Heparan sulfate (HS) also showed an increase in amyloid deposits, but with less reactivity than CS in the small arterioles or venules. Basement membrane structures stained positively for laminin and collagen type IV were replaced by negative amyloid deposits. In the AL cases, the muscularis propria of the gastrointestinal tract was involved in amyloid deposits, as seen for the B2M type, but the vascular amyloid deposits were localized in the media and adventitia of larger vessels. Immunoreactivity for HS was more intense than that for CS, and no increase in laminin or collagen type IV was observed. In the AA cases, amyloid deposits were distributed in the capillaries, small arterioles, interstitium of the myocardium and mucosa. Immunoreactivity for laminin and collagen type IV was marked, and more intense than that for HS and CS. Although the existence of a direct relationship between increase in extracellular matrix material and amyloidogenesis remains to be proven, the observed variation in extracellular matrix changes in the background of each type of amyloidosis may indicate different binding sites of the amyloid precursor proteins, resulting in the specific histological features and distribution.

Adult↗
PubMed1997

Molecular handling of photosynthetic proteins for molecular assembly construction.

Methods of constructing proteins were examined with special reference to the molecular assembly using photosynthetic RCs as membrane proteins. Molecular assemblies at the interfaces were studied by LB films, adsorption to the surface and reconstitution into liposomes and bilayer lipid membranes. The applications of biological specific ligands (recognition and binding), combinatorial chemical method, 2-D and 3-D order array assemblies and modification of protein molecules to make fusion proteins, as well as physical methods of manipulation of molecules by AFM tips and electric fields were reviewed.

Adsorption↗
PubMed1997

Evaluation of patellar retinacular tension during total knee arthroplasty. Special emphasis on lateral retinacular release.

Tension of a suture placed to the patella to close the medial capsule during 35 primary total knee arthroplasties was measured. The increase in tension with flexion after arthrotomy was significantly smaller in 10 knees with a subvastus incision (subvastus group) than in 25 knees with a standard medial parapatellar incision (standard group). With the prosthesis in place, the patella showed maltracking with the no-thumb technique in 1 knee (10%) of the subvastus group and in 9 knees (36%) of the standard group. A lateral retinacular release was performed in 5 of these 10 knees but not in the remaining 5 knees because the increase in tension was a minimum. There was no case of patellar maltracking at an average follow-up period of 2.1 years after surgery, suggesting that a lateral release is not always needed if retinacular tension shows no significant increase, even cases where the patella dislocates with the no-thumb technique.

Aged↗
PubMed1997

Ultrastructural organization of hemodialysis-associated beta 2-microglobulin amyloid fibrils.

Fibrils of hemodialysis-associated beta 2-microglobulin amyloid were examined by high resolution electron microscopy and immunohistochemical labeling. The amyloid containing tissues obtained through autopsy were prepared for thin section observations. In contrast to other forms of amyloid, the most conspicuous feature of these fibrils were their curved conformations. The fibril core showed ultrastructural and immunohistochemical features in common with the core of connective tissue microfibrils and of previously observed fibrils of experimental murine AA amyloidosis and familial amyloid polyneuropathy (FAP). The core was wrapped in a layer of 3 nm wide ribbon-like "double tracked" structures identified as chondroitin sulfate proteoglycan (CSPG) with immunogold labeling as well as from the results of previous in vitro experiments. Finally, the outer surface of the fibril was associated with a loose assembly of 1 nm wide filaments immunohistochemically identified as beta 2-microglobulin. This is similar to the manner in which AA protein and transthyretin filaments are associated with their respective fibrils. The results of this study provide an additional example for the concept that amyloid fibrils in general are microfibril-like structures externally associated with amyloid protein filaments. An unusual feature of the fibrils of hemodialysis-associated amyloid, however, is the presence of a peripheral layer composed of CSPG rather than of heparan sulfate proteoglycan (HSPG) as in the case of the other two amyloids above. These chondroitin sulfate chains in the outer CSPG layer may be less effective in providing rigidity to the fibril core, thus allowing for the curved conformations of beta 2-microglobulin amyloid fibrils.

Aged↗
PubMed1997

1-Alkenyl group of ethanolamine plasmalogen derives mainly from de novo-synthesized fatty alcohol within peroxisomes, but not extraperoxisomal fatty alcohol or fatty acid.

The origin of the 1-alkenyl group of ethanolamine plasmalogen was investigated. Three candidates were examined for the fatty alcohol forming the 1-alkenyl group. [1-(14)C]Hexadecanoic acid, [1-(14)C]hexadecanol, or [1-(14)C]lignoceric acid was administered to rats treated with 0.25% clofibrate-chow for 2 weeks. At 0.5, 1, 2, 3, and 4 h after administration of the radiolabeled compound, rats were killed and ethanolamine-containing phosphoglyceride (EPG)-rich fraction was isolated from the liver. The components of the 1-radyl group in EPG-rich fraction were separated and the radioactivity was determined. The radiolabel after administration of [1-(14)C]hexadecanoic acid or [1-(14)C]hexadecanol was almost wholly incorporated into diacyl-type glycerophosphoethanolamine (GPE), and was predominantly found in hexadecanoic acid fraction. Therefore, the long-chain fatty acid may be incorporated intact into the diacyl groups, and the long-chain fatty alcohol may be similarly incorporated after oxidation to the acid. In contrast, the radiolabel after the administration of [1-(14)C]lignoceric acid was found in the 1-alkenyl group of ethanolamine plasmalogen. After hydrolysis of the 1-alkenyl group by treatment of the plasmalogen with HCl vapor, the radiolabeled products were chiefly stearaldehyde and palmitaldehyde. The above data indicate that nascent fatty alcohol de novo synthesized from acetyl-CoA derived by peroxisomal beta-oxidation is almost exclusively used as the fatty alcohol forming the 1-alkenyl group of ethanolamine plasmalogen.

Aldehydes↗
PubMed1997

Biphasic synovial sarcoma of the peritoneal cavity with t(X;18) demonstrated by reverse transcriptase polymerase chain reaction.

A case of a biphasic synovial sarcoma, arising on the inner surface of the anterior abdominal wall of a 13-year-old girl, is reported. Although the tumor showed rather typical histological and immunohistochemical features for synovial sarcoma, its unusual clinical presentation and anatomical location caused diagnostic difficulty, especially with regard to differentiation from a malignant mesothelioma. Applying reverse transcriptase polymerase chain reaction (RT-PCR) analysis, the SYT-SSX2 chimeric gene transcripts that result from the translocation, t(X;18)(p11.2;q11.2), found in most synovial sarcomas could be demonstrated. Thus, this RT-PCR approach is a reliable method for confirming the diagnosis of synovial sarcomas in unusual locations.

Adolescent↗