Brain CRMP forms heterotetramers similar to liver dihydropyrimidinase

The cytoplasmic collapsin response mediator protein CRMP62 is involved in the signaling cascade initiated by collapsin-1, which collapses neuronal growth cones. To investigate the mechanism of CRMP action, we screened mouse and human fetal cDNA libraries by the yeast two-hybrid method with CRMP as bait. Clones encoding CRMP1 and CRMP4 were isolated, suggesting that the CRMPs form multimers. This finding was confirmed by expressing various rat CRMP cDNAs in the yeast two-hybrid system. Rat CRMP isoforms show differential association with one another. Heterooligomerization is preferred in both two-hybrid and in vitro binding assays. Purified bovine brain CRMP migrates as a tetramer during size exclusion chromatography. Examination of binding with truncated forms of CRMPs indicates that the avid association of CRMPs requires nearly intact proteins. Through the analysis of CRMP chimeras, CRMP amino acids 8-134 and 281-435 are found to be essential for CRMP oligomerization. The tetrameric structure of CRMP resembles that of liver dihydropyrimidinase (DHPase), a protein that shares sequence similarity with the CRMPs. Although purified brain CRMP does not hydrolyze several DHPase substrates, it is likely that a related activity accounts for CRMP participation in neuronal growth cone signaling.     

glsA, a Volvox gene required for asymmetric division and germ cell specification, encodes a chaperone-like protein

The gls genes of Volvox are required for the asymmetric divisions that set apart cells of the germ and somatic lineages during embryogenesis. Here we used transposon tagging to clone glsA, and then showed that it is expressed maximally in asymmetrically dividing embryos, and that it encodes a 748-amino acid protein with two potential protein-binding domains. Site-directed mutagenesis of one of these, the J domain (by which Hsp40-class chaperones bind to and activate specific Hsp70 partners) abolishes the capacity of glsA to rescue mutants. Based on this and other considerations, including the fact that the GlsA protein is associated with the mitotic spindle, we discuss how it might function, in conjunction with an Hsp70-type partner, to shift the division plane in asymmetrically dividing cells.     

Prognostic value of blood lactate, base deficit, and oxygen-derived variables in an LD50 model of penetrating trauma

OBJECTIVE: To determine whether blood lactate, base deficit, or oxygen-derived hemodynamic variables correlate with morbidity and mortality rates in a clinically-relevant LD50 model of penetrating trauma. DESIGN: Prospective, controlled study. SETTING: University research laboratory. SUBJECTS: Anesthetized, mechanically-ventilated mongrel pigs (30+/-2 kg, n = 29). INTERVENTIONS: A captive bolt gun delivered a penetrating injury to the thigh, followed immediately by a 40% to 60% hemorrhage. After 1 hr, shed blood and supplemental crystalloid were administered for resuscitation. MEASUREMENTS AND MAIN RESULTS: After penetrating injury, 50.7+/-0.3% hemorrhage (range 50% to 52.5%), and a 1-hr shock period, seven of 14 animals died, compared with six of six animals after 55% to 60% hemorrhage, and 0 of nine animals after < or =47.5% hemorrhage. Only two of 13 deaths occurred during fluid resuscitation. At the LD50 hemorrhage, peak lactate concentration and base deficit were 11.2+/-0.8 mM and 9.3+/-1.5 mmol/L, respectively, and minimum mixed venous oxygen saturation, systemic oxygen delivery, and systemic oxygen consumption were 33+/-5%, 380+/-83 mL/min/kg, and 177+/-35 mL/min/kg, respectively. For comparison, baseline preinjury values were 1.6+/-0.1 mM, -6.7+/-0.6 mmol/L, 71+/-3%, 2189+/-198 mL/min/kg, and 628+/-102 mL/min/kg, respectively. Of all the variables, only lactate was significantly related to blood loss before and after fluid resuscitation in the 16 survivors. However, r2 values were relatively low (.20 to .50), which indicates that only a small fraction of the hyperiactacidemia was directly related to tissue hypoperfusion. In the whole population of survivors and nonsurvivors, both lactate and base deficit (but none of the oxygen-derived variables) correlated with blood loss. CONCLUSIONS: Arterial lactate is a stronger index of blood loss after penetrating trauma than base deficit or oxygen-derived hemodynamic variables. The reliability of arterial lactate depends on several factors, such as the time after injury, the proportion of survivors and nonsurvivors in the study population, and on factors other than tissue hypoxia.     

Conservative surgical therapy for penile and urethral carcinoma

OBJECTIVES: Invasive penile and urethral tumors are traditionally treated with aggressive excision that requires involved organ and adjacent organ sacrifice. An alternative approach seeks to completely excise the tumor with adequate margins while preserving form and function of the organ. We present 6 patients who underwent such organ-sparing surgery. METHODS: Six selected cases (4 penile and 2 urethral) are presented with operative photographs and pertinent data. RESULTS: Three distal tumors of the penis were treated with excision limited to the glans with histopathologic findings of verrucous carcinoma, melanoma, and angiosarcoma. One patient with squamous cell carcinoma of the distal shaft refused partial penectomy and underwent a local wedge resection. A patient with locally advanced bulbourethral transitional cell carcinoma (TCC) refused cystourethrectomy and underwent an anterior urethrectomy and perineal urethrostomy. A 48-year-old woman with an adenocarcinoma contained in a very distal urethral diverticulum underwent simple diverticulectomy and excision of distal urethra. Postoperative voiding and sexual function were well preserved. Follow-up was 12 to 48 months. The patient with angiosarcoma died of lung metastases at 48 months with no local disease, and the patient with bulbourethral TCC developed pelvic disease at 12 months with no local recurrence and died of metastases at 25 months. CONCLUSIONS: Organ-sparing surgery is appropriate in selected patients on the basis of stage and location, high risk of distant failure, and patient disposition. Close follow-up is necessary. Comanagement with reconstructive and oncologic specialists optimizes results and outcomes.