Segmented gene conversion as a mechanism of correction of 18S rRNA pseudogene located outside of rDNA cluster in D. melanogaster

INTRODUCTION: Acute scrotum in the pediatric age is mainly related to surgical causes. Spermatic cord torsion and inguinoscrotal hernia must be ruled out first, because of the possible ischemic damage to gonadal tissue and therefore surgery is sometimes performed directly, thus representing also a diagnostic tool. Spermatic cord torsion is found in two age ranges, namely: the neonatal period, where it usually represents the evolution of an intrauterine process, and the peripubertal period, which is more frequent. An unquestionable and prompt diagnosis is particularly needed because of the extreme sensitivity of gonadal tissue to ischemia. In this particular field, color and power Doppler US, depicting gonadal flow, have greatly increased diagnostic imaging capabilities, which were previously limited to B-mode US. MATERIAL AND METHODS: We examined 19 peripubertal patients with the diagnosis of spermatic cord torsion made on the basis of B-mode US and then confirmed with color Doppler. RESULTS: We found two signs which can be considered highly suggestive of spermatic cord torsion: the spiral twist of spermatic vessels and the peculiar extent of reactive hydrocele, caused by the bell clapper anomaly of the vaginal sac. CONCLUSIONS: The above US patterns are very helpful to diagnose spermatic cord torsion.     

Boundary conditions for excitation propagation equations which do not distort the picture of impulse movement

New boundary conditions for the equations of excitation propagation are suggested. These conditions prescribe in the point in the end of the fiber the action potential which would be developed there, if half-infinite fiber would proceed further. The conditions suggested 1) in a number of cases allow to obtain an undistorted picture of excitation propagation, e.g. the picture when impulses fall out when a chain of impulses moves along the fiber; 2) save computer time and memory. Boundary conditions for syncitium and flat medium are considered.     

Laparoscopy in the differential diagnosis of acute disorders of the mesenteric blood circulation and acute pancreatitis

Difficulties in differential diagnosis of acute impairement in mesenterial circulation (AIMC) and acute pancreatitis (AP) were noted in 39 patients. At laparoscopy, AP was diagnosed in 21 patient, AIMC--in 11, acute appendicitis--in 3, perforative gastric ulcer--in 2. In 2 patients, no pathologic changes were revealed. The diagnosis established by means of laparoscopy, in 9 patients was confirmed at operation, in 10--at autopsy, in the remaining patients--at dynamic follow-up and use of other methods of investigation. Use of therapeutic laparoscopy contributed to improved of the results of treatment of the patients.     

Hemoglobin M equon beta 41 (C7) phenylalanine leads to tyrosine

A severe hemolytic crisis was observed in a 34-yr-old female of English-Irish extraction following a viral illness treated with acetaminophen. Heinz bodies and heat instability were present only during a transient hemolytic event. A challenge dose of acetaminophen caused no detectable hematologic abnormality. Structural studies of the hemoglobin during hemolysis and again after complete recovery localized the abnormality to tryptic peptide beta Tp-5, and automated sequencing of I 125-labeled beta chains indicated a replacement of phenylalanine (C7) beta 41 by tyrosine. Substitution of the next residue, phenylalanine (CD1) beta 42 by serine (Hb Hammersmith), has resulted in chronic severe Heinz body hemolytic anemia. The lack of chronic anemia in the present disorder may reflect the different relationships of beta41 and beta 42 and/or the similarities in volume and hydrophobicity of tyrosine and phenylalanine. It is suggested that substitution of tyrosine for phenylalanine in Hb Mequon may disturb the critical environment around the heme group and render it susceptible to oxidative denaturation in the presence of infections and/or drugs.