Biomedical subjects
Publications and source records attributed to J D Siegal.
Three patients beyond the neonatal period with group B streptococcal infection were presented, including acute osteomyelitis and septic arthritis, bacteremia and septicemia. Serotyping was done in two patients. One was type Ia and the other was type III. All patients recovered from the disease.
To overcome obstacles to the regeneration of crushed dorsal root fibers at the dorsal root entry zone, we have employed specially designed Millipore implants coated with embryonic astrocytes to serve as a substrate for axonal growth. This strategy was successful in promoting the growth of crushed dorsal root axons into the grey matter of the adult mammalian spinal cord in a small number of animals. Fiber ingrowth into the spinal cord was closely associated with the surface of the polymer implant. In addition, unique terminal arbor malformations, not normally present, were seen in several animals. A consistent finding was the presence of a limited inflammatory response in regions immediately adjacent to the implant where axons penetrate the spinal cord. Our findings suggest that providing the dorsal root entry zone with an embryonic milieu can stimulate a limited amount of axonal regeneration into the adult mammalian spinal cord.
To assess the role of white matter inhibition as a barrier to neurite outgrowth in vivo, we unilaterally transected three consecutive lumbar dorsal roots (L4-L6), incised the spinal cord, and transplanted the peripheral stump of L4 either medially onto the white matter of the dorsal columns or laterally, just superficial to the gray matter of the dorsal horn at the level of L5. Three weeks to seven months later, the translocated root was retransected, and its central stump was anterogradely labeled with HRP. The staining pattern demonstrated that regenerating sensory axons had entered the spinal cord from both medially and laterally placed roots. Axonal staining from medially placed dorsal roots (onto the white matter of the dorsal columns) was sparse and limited to the white matter. Staining of laterally placed roots revealed a small subpopulation of regenerating axons which had entered the gray matter and formed terminal arbors. Successful axonal regeneration into the gray matter, albeit minimal, was associated with a localized and limited inflammatory response near the sites of axonal ingrowth.
We examined a series of 29 surgical specimens of benign and malignant human prostate tissue for the expression of both the cHa-ras and c-myc protooncogenes. Northern blots were prepared using polyadenylated mRNA extracted from nine prostatic adenocarcinomas, 19 benign hypertrophied prostates (BPH) and one normal prostate. When the Northern blots were hybridized to a probe for cHa-ras, only one specimen of BPH showed an appreciable amount of the 1.2-kb transcript homologous to cHa-ras. Upon reprobing these blots with c-myc, six cancers showed a considerable amount of a 2.4-kb transcript homologous to c-myc. Three other cancers and all the benign tissue showed little or no detectable 2.4-kb c-myc transcript. On retrospective analysis, the cancers with elevated c-myc transcripts were found to have a Gleason score of 5 and above (poorly differentiated tumors), while the cancers with little or no c-myc transcripts were all of Gleason score 4 and lower. Finally, we compared our ability to detect c-myc transcripts in mRNA extracted from a surgically derived prostate tumor with mRNA extracted from the same tumor subject to a sham electrocautery procedure, as would occur during transurethral resection. The electrocautery procedure decreased both the intensity and the integrity of the c-myc signal in mRNA from the tumor. Thus, our exclusive use of surgically derived prostate tumors may be the reason we are able to detect an elevation in the expression of c-myc mRNA in high-grade tumors.
Ligand binding at many physiologically relevant receptors is regulated by divalent cations. To determine whether [3H]-spiroperidol binding sites in prefrontal cortex might be physiologically relevant receptors, we examined the effect of ions on the binding of this ligand in postmortem human prefrontal cortex. Our results indicate that several cations decreased [3H]-spiroperidol binding in a dose-dependent fashion. Of these, Cd++ and Zn++ were the most able to decrease [3H]-spiroperidol binding with IC50 of 5.5 +/- 2.4 X 10(-6)M and 5.6 +/- 1.1 X 10(-5)M respectively. These findings indicate that [3H]-spiroperidol may bind at physiologically relevant receptors in human prefrontal cortex.
New tests consisting of modifications of the inverted Mason jar test confirm our previously reported studies which showed that woven and nonwoven surgical materials vary greatly in their ability to serve as barriers against moist bacterial strike-through. Among the woven materials, only tightly woven Pima cloth or materials treated with Quarpel waterproofing process or with polythene layer lamination was invariably resistant. However, tight-woven Pima cloth, which had been treated with Quarpel became permeable after 100 washing-sterilizing cycles. Of the nonwoven materials, single-layer nonwoven materials tended to unevenly permeable to moist bacterial strike-through. Only the front and sleeves of nonwoven gowns reinforced with polyethelene layer were invariably resistant to moist contamination.