HPLC-studies on nonmercapt-mercapt conversion of human serum albumin

Human mercaptalbumin (HMA) and nonmercaptalbumin (HNA) could be separated by high-performance liquid chromatography (HPLC) at neutral pH. Using HPLC, the present authors found the nonmercapt-mercapt conversion (HNA ← HMA) during hemodialysis and the mercapt-nonmercapt conversion (HMA ← HNA) after hemodialysis in chronic renal failure, indicating HMA as the covalent carrier protein for sulfur-containing amino acids.     

Validity of positron emission tomography using fluoro-2-deoxyglucose for the preoperative evaluation of endometrial cancer

To clarify the validity of positron emission tomography using fluoro-2-deoxyglucose (FDG-PET) for the preoperative evaluation of endometrial cancer, we analyzed the preoperative FDG-PET images of both primary and metastatic lesions of 30 patients with endometrial cancer, and compared them with computed tomography (CT) and/or magnetic resonance imaging (MRI) images and the results of postoperative pathologic findings. As to the primary lesions, FDG-PET could easily identify the cancer, and the sensitivity was 96.7%, which tended to be higher than that of 83.3% by CT/MRI. As to the evaluation of retroperitoneal lymph node metastasis, FDG-PET could detect none of five cases of lymph node metastatic lesions of up to 0.6 cm in diameter but had higher specificity (100%) compared with CT/MRI (85.7%). The sensitivity of FDG-PET for detection of extrauterine lesions excluding retroperitoneal lymph nodes was 83.3% and was superior to that of CT/MRI (66.7%), although there was no difference in the specificity between the modalities (100%). The diagnostic ability of FDG-PET was limited if used alone, but FDG-PET gave additional information especially with regard to the extrauterine lesions whose significance could not be determined on CT/MRI. However, we also found that FDG-PET could not identify any lymph node metastasis less than 1 cm in diameter; therefore, a negative finding of lymph node metastasis on FDG-PET should not be interpreted as a reason for omitting retroperitoneal lymph node dissection for the precise surgical staging of endometrial cancer.     

Synthesis and central nervous system actions of thyrotropin-releasing hormone analogs containing a 1-substituted 2-oxoimadazolidine moiety*

A series of thyrotropin-releasing hormone (TRH) analogs in which the pyroglutamic acid residue was replaced by (S)-2-oxoimidazolidine-4-carboxylic acid (Oic-OH) and the related derivatives was prepared, and the central nervous system (CNS) actions were examined. Of these, 1-benzyl-Oic-His-Pro-NH₂ (2c) showed the most potent activities, which were 1.5-8 times greater than those of TRH. Moreover, the thyrotropin (TSH)-releasing activity of 2c was about 1/16 times weaker than that of TRH.     

1H-n.m.r. studies on cross-relaxation phenomena in bovine mercaptalbumin (BMA) solution and partially hydrolyzed bovine plasma albumin (BPA*) gel

Bovine plasma albumin Fr. V(BPA) contains small amounts of proteolytic enzyme which catalyzes a very limited cleavage of BPA in the F-form near pH 3.8, resulting in the formation of partially hydrolyzed BPA(BPA*). BPA* had a tendency to form a transparent gel at pD 4.0 (pD range of the F-form) above 7%. Highly purified proteolytic enzyme-free bovine mercaptalbumin (BMA) was in a transparent solution at pD 4.0 even at 12.4%. after 5 days incubation at 35°. Cross-relaxation times (T_IS) between irradiated protein protons and observed protons, such as side chain and water protons, were studied on BMA solution and BPA*-gel. T_IS values of BMA solution, obtained by the saturation transfer (SATUR) and inversion recovery (INVER) methods, were a single kind of T_IS for each side chain. Those of BPA*-gel by the SATUR method indicated the presence of two kinds of T_IS, that is, short and long T_IS values for each side chain. However, those by the INVER method showed a single kind of T_IS for each side chain, corresponding to the long T_IS value by the SATUR method. The short T_IS values of BPA*-gel, observed by the SATUR method, may be due to immobile joint parts of fibrous BPA* aggregates. T_IS values from protein to water protons (T_IS(HDO)) in BPA*-gel, obtained by the INVER method, were far shorter than those in BMA solution, indicating a large amount of hydration of BPA* and rapid exchange between bound and bulk water in the gel state.     

Dyschromatosis symmetrica hereditaria associated with neurological disorders

Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal dominant inheritance caused by a mutation of adenosine deaminase acting on the RNA 1 gene (ADAR1). It is characterized by a mixture of hyper‐ and hypopigmented macules on the back of the hands and feet. The pathomechanism by which the ADAR1 gene mutation induces DSH has not been clarified yet. We experienced an 11‐year‐old male DSH patient associated with dystonia, mental deterioration and brain calcification, who had a mutation of p.G1007R in the ADAR1 gene. This mutation had already been reported in a patient with similar neurological symptoms by Tojo et al. Additionally, a patient with DSH associated with torsion dystonia was reported by Patrizi et al., but gene analysis was not carried out. Only three cases with neurological disorders have been reported, although more than 50 mutations of the ADAR1 gene causing DSH have been reported and none of them had any neurological symptoms. Therefore, we suggest that neurological disorders rarely develop in DSH.     

Polyphosphoric acid treatment promotes bone regeneration around titanium implants

Summary  This study was conducted to evaluate the effect of polyphosphoric acid (PPA) treatment on bone regeneration around titanium (Ti) implants in vivo . Adsorption of PPA by Ti was achieved by immersing Ti implants (2 mm in diameter, 4 mm in length) in different concentrations of PPA solution (0, 1 and 10 wt%) for 24 h at 37 °C after proper Ti surface cleaning. The treated Ti implants were implanted on 8-week-old-male rat ( n  = 30) tibiae. Two or four weeks after implantation, all animals were deeply anaesthetized and underwent perfusion fixation. Ten specimens in each condition were further immersed in the same fixative for 1 week and eventually embedded in polyester resin. Afterwards, undecalcified sections were ground to a thickness of approximately 70 μm parallel to the long axis of the implant. The sections were stained with basic fuchsine and methylene blue and then examined by light microscopy. For quantitative evaluation of bone regeneration around the implants, the bone-implant contact ratio (BICR) was determined. Polyphosphoric acid treatment of the Ti implant surface significantly enhanced direct bone contact to the Ti surface. Especially, the BICRs of the 1 wt% PPA-treated Ti implants were significantly higher than those of the control untreated Ti implants, both 2 and 4 weeks after implantation. At 4 weeks, 10 wt% PPA-treated implants also significantly increased the BICR as compared to that of the untreated Ti implants. These results suggest that PPA treatment promotes osteoconductivity of Ti in vivo .     

A Case of Pacemaker Lead Fracture Associated with Thoracic Outlet Syndrome

A pacemaker lead fracture in the left subclavian vein was caused by compression of the clavicle and the first rib; subsequent coil elongation at the same site on the right side was observed in the replacement lead in a patient with thoracic outlet syndrome. Venography showed narrowing of the subclavian vein at the site where the lead abnormalities were observed. This case illustrates that a lead in the subclavian vein can be easily damaged when a patient has thoracic outlet syndrome.     

Electrophysiologic Evaluation of Asymptomatic Patients with the Wolff-Parkinson-White Pattern

In the past 4 years, 34 asymptomatic patients with the Wolff-Parkinson-White (WPW) pattern underwent electrophysiologic study. The effective refractory period (ERP) of antegrade conduction over the accessory pathway was 288 +/- 29 msec. In three asymptomatic patients (9%), the antegrade ERP of the accessory pathway was shorter than 250 msec. The antegrade ERP of the accessory pathway became shorter than 250 msec in an additional 12 of 22 (55%) patients after isoproterenol administration. Nineteen (56%) of the asymptomatic patients showed the absence of retrograde conduction over the accessory pathway even after isoproterenol administration. The rate of induction of orthodromic reciprocating tachycardia in the asymptomatic WPW patients was 15% (5/34), which was significantly lower than that in the symptomatic patients. These data suggest that in the asymptomatic patients, the absence of retrograde conduction over the accessory pathway is the reason they remained asymptomatic, free of reciprocating tachycardia. However, even in the asymptomatic patients, some had the accessory pathway in which antegrade ERP was shorter than 250 msec. They may result in rapid ventricular conduction over the accessory pathway when atrial fibrillation develops.