Cyclic peptides

In order to investigate the role of the L-2-hydroxy-3-methylbutanoic acid residue at position 2 of AM-toxin I (cyclic tetradepsipeptide) on necrotic activity for apple leaves, two analogs, [L-lactic acid²] AM-toxin I and [L-2-hydroxy-4-methylpentanoic acid²] AM-toxin I, were synthesized by the conventional method for peptide synthesis. The toxic activity of the former analog was much weaker than that of the natural AM-toxin I and the latter analog. CD spectra of AM-toxin I and these analogs were correlated to those toxic activities, indicating that bulkiness of the side chain at position 2 is important for the maintenance of active conformation and the induction of necrotic activity.     

Prognostic significance of thrombocytosis in renal cell carcinoma patients

Background: Thrombocytosis has been reported in many types of malignancies and has been studied as a prognostic factor. In the present study, we examined the incidence of thrombocytosis in patients with renal cell carcinoma (RCC) in order to evaluate the prognostic value of thrombocytosis. Methods: One hundred and ninety‐six patients treated by radical nephrectomy for RCC were enrolled in this study. We divided the patients into a normal platelet count group and a thrombocytosis group according to the presurgical platelet count. The two groups were compared pathologically and clinically, including prognosis. Results: Thrombocytosis was present in 16 patients (8.2%). Platelet counts had normalized after nephrectomy in all patients with thrombocytosis. There was no correlation between histological type or grade and thrombocytosis. However, there were correlations between thrombocytosis and tumor size and tumor stage. Patients with thrombocytosis had a worse prognosis than patients without thrombocytosis (P = 0.0028). When adjusted for stage or tumor size, the correlation was limited to low stage (stage 1 + 2: P = 0.0041, stage 3 + 4: P = 0.2983) or small tumors (tumor size: ≤4 cm, P = 0.0021; 4–7 cm, P = 0.0142; >7 cm, P = 0.8158). Conclusion: Thrombocytosis is an inexpensive and easy tool with which to evaluate the prognosis of RCC patients in daily medical practice.     

Changes in work performances in obstructive sleep apnea patients after dental appliance therapy

Abstract The effects of dental appliances on work performances of obstructive sleep apnea syndrome (OSAS) is not well examined. This study evaluated the polysomnographic and psychological findings before and after therapy. Nine patients were diagnosed OSAS by nocturnal polysomnography. The psychological battery was performed from 13:00 to 14:00, which consisted of Uchida-Kraepelin psychodiagnostic test (U-K's test) and Bourdon's cancellation test (Bourdon's test). Approximately 3 months after the treatment, the examinations were performed. Apnea and desaturation index decreased significantly after the therapy. In addition, sleep architecture improved after the therapy compared with that before the therapy. Dysfunction of task performances, such as mean level of work amounts in U-K's test, mean error, mean performance time and mean deviation in Bourdon's test improved after therapy. We conclude that dental appliances therapy is effective not only to apnea but also to work performance in OSAS.     

Interaction of lipophilic peptides derived from mastoparan with phospholipid vesicles

Various kinds of lipophilic peptides were prepared by acylation of an ct-helical peptide, mastoparan, to investigate the effects of acyl groups on the interaction of peptides with phospholipid membranes. α-Helicity of the peptides was increased by introduction of long acyl groups. Acyl peptides showed different membrane-perturbation activities for neutral and acidic phospholipid vesicles, whereas a peptide with a dialkycarbamoyl group always exhibited a strong activity. High hemolytic activities were observed for the peptides with long acyls (single or double chain). These results indicate that lipophilic groups introduced to mastoparan contribute greatly to the interaction of the peptide with phospholipid membranes with lengthening of the acyl chain and that the structural character of the lipophilic group also influences the conformation of the peptide.     

Interaction of α-helical peptides with phospholipid membrane: effects of chain length and hydrophobicity of peptides

To investigate the interaction of amphiphilic α-helical peptides with phospholipid membranes, we synthesized Ac-(Leu-Ala-Arg-Leu)₃-NHcH₃ (4₃) and three derivatives, in which the chain length and the size of the hydrophobic region of the peptides were different from each other. These peptides formed an α-helical structure in the presence of vesicles. In the membrane-perturbation measurement, only 4₃ showed a strong membrane-perturbation activity below phase-transition temperature (25°C), but above phase-transition temperature (50°C), most peptides showed similar strong activities. On the other hand, in membrane-fusion measurement the long peptides, e.g., Ac-(Leu-Ala-Arg-Leu)₃-(Leu-Arg-Ala-Leu)₃-NHCH₃, had strong activities at low peptide concentrations at 25°C. The present study indicated a parallel relationship did not always exist between membrane fusion and perturbation caused by peptides.     

Papillary cystadenocarcinoma of the prostate

A giant cystic formation was found behind the prostate of a 69-year-old man who presented with urinary retention. Ultrasonography, computed tomography scans and magnetic resonance imaging revealed a large cystic intrapelvic mass and biopsy of the cyst wall diagnosed papillary cyst adenocarcinoma. Immunohistochemically, the tumor originated from the prostate.