Prune belly syndrome (PBS) has been recognized since 1950 as the triad of absent abdominal wall musculature, undescended testes, and urinary tract anomalies. The etiology, however, remains uncertain. Theories of mesenchymal maldevelopment, obstruction, and genetic origin have been proposed. To evaluate the role of lower urinary tract obstruction as it relates to prostatic development and PBS, we studied the lower urinary tract of 15 cases of PBS, 8 cases of posterior urethral valves (PUV), and 34 age-matched controls. It is generally accepted that prostatic growth and development are dependent on mesenchymal-epithelial interactions. We evaluated the mesenchymal and epithelial differentiation and relationships, and found distinctly different and consistent abnormalities between PBS and PUV as compared with one another and controls. The findings suggest that in PBS, prostatic growth and development are hindered because of destruction or absence of the appropriate primitive mesenchyme. Our studies could not definitely exclude very early obstruction as a cause of the findings because of lack of appropriate fetal material.

The leptomyxid amoeba Balαmuthia mandrillaris, previously believed to be a harmless soil-inhabiting organism, is now known to be a rare but consistently lethal cause of meningoencephalitis in humans. We report a case of amebic meningoencephalitis caused by B. mandrillaris which presented as a febrile illness with acute hydrocephalus.

The circular dichroic spectral features of (A)10-20, (C)10-20, A8UGU6, poly(A), and poly(C), at both neutral and acidic pH values and in the presence and absence of Mg2+, are significantly altered by Escherichia coli initiation factor 3 (IF3), implying the occurrence of protein-induced changes in nucleic acid secondary structure. Similarly, the circular dichroic spectral characteristics of helical poly(U), poly-(A)-poly(U), and poly(I)-poly(C) are modified by IF3. However, no structural perturbation of poly(A)-poly(U) occurs in the absence of Mg2+ by IF3. The oligonucleotides (A)10-20 and (C)10-20 at both pH 7.5 and 5.5 titrate to end point of 26 +/- 4 nucleotide residues per IF3 [except (C) 10-20 at pH 5.5 which titrates to 17 +/- 1 nucleotide residues per IF3], whereas the hairpin A8UGU6 under similar conditions at neutral pH and in the presence of Mg2+ titrates to an end point of 56 +/- 3 nucleotide residues per IF3, thereby suggesting the presence of multiple binding sites on the protein. By contrast, poly(A) and poly(C) at neutral pH and in the absence of Mg2+ titrate to an end point of 13 +/- 1 nucleotide residues per IF3. The occurrence of significant light-scattering artifacts precluded a determination of the end point stoichiometry in most other cases. The circular dichroic spectra of E. coli tRNA, MS2 RNA, phiX174 DNA, and sonicated calf thymus DNA were unaffected by IF3 at physiological concentrations. Addition of an equimolar mixture of IF3 and ribosomal protein S1 titrates the circular dichroism of poly(C) at acid pH as did S1 alone. However, addition of IF3 to mixture of poly(A) and S1 at neutral pH did not result in significant titration of the optical activity until IF3 was in excess over S1, even though filter binding assays indicate normal IF3 binding to the polynucleotide. The possible relation of these observations to the biological function of IF3 is briefly considered.

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