A comparison of cocaine, lidocaine with epinephrine, and oxymetazoline for prevention of epistaxis on nasotracheal intubation

The alpha-adrenergic agonist oxymetazoline was compared to cocaine and to lidocaine with epinephrine with respect to prevention of epistaxis on nasotracheal intubation. The nares of three groups of 14 patients each were topically pretreated with 4% lidocaine with 1:100,000 epinephrine (group 1), 10% cocaine (group 2), or 0.05% oxymetazoline (group 3) prior to nasotracheal intubation. After intubation, epistaxis was estimated on a scale of 0 to 3, with 0 indicating no bleeding, 1 representing blood on the nasotracheal tube only, 2 indicating blood pooling in the pharynx, and 3 representing blood in the pharynx sufficient to impede intubation. Only 29% of the patients in group 1 displayed no bleeding, whereas 57% of those in group 2 and 86% of those in group 3 had no bleeding. Nonparametric analysis showed a statistically significant difference (p less than 0.013) between oxymetazoline and lidocaine with epinephrine. In addition, heart rate (HR) and blood pressure (BP) were examined prior to administration of the medications; at 5 minutes, 10 minutes, and 15 minutes after administration of the medications; and after intubation. No significant differences were noted (p greater than 0.05) between the medications except for a slightly higher systolic BP for cocaine than for lidocaine with epinephrine at 15 minutes. The results of this double-blind, randomized trial demonstrate that the alpha-adrenergic agonist oxymetazoline is as effective as cocaine, and more effective than lidocaine with epinephrine, for the prevention of epistaxis associated with nasotracheal intubation.     

Functional analysis of 13 GBA mutant alleles identified in Gaucher disease patients: Pathogenic changes and "modifier" polymorphisms

Gaucher disease, the most prevalent sphingolipidosis, is caused by the deficient activity of acid beta-glucosidase, mainly due to mutations in the GBA gene. Over 200 mutations have been identified worldwide, more than 25 of which were in Spanish patients. In order to demonstrate causality for Gaucher disease, some of them: c.662C>T (p.P182L), c.680A>G (p.N188S), c.886C>T (p.R257X), c.1054T>C (p.Y313H), c.1093G>A (p.E326K), c.1289C>T (p.P391L), c.1292A>T (p.N392I), c.1322T>C (p.I402T), and the double mutants [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]) and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]), were expressed in Sf9 cells using a baculovirus expression system. Other well-established Gaucher disease mutations, namely c.1226A>G (p.N370S), c.1342G>C (p.D409H), and c.1448T>C (p.L444P), were also expressed for comparison. The levels of residual acid beta-glucosidase activity of the mutant enzymes produced by the cDNAs carrying alleles c.662C>T (p.P182L), c.886C>T (p.R257X), c.1054T>C (p.Y313H), c.1289C>T (p.P391L), and c.1292A>T (p.N392I) were negligible. The c.1226A>G (p.N370S), c.1322T>C (p.I402T), c.1342G>C (p.D409H), c.1448T>C (p.L444P), and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]) alleles produced enzymes with levels ranging from 6 to 14% of the wild-type. The three remaining alleles, c.680A>G (p.N188S), c.1093G>A (p.E326K), and [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]), showed higher activity (66.6, 42.7, and 23.2%, respectively). Expression studies revealed that the c.1093G>A (p.E326K) change, which was never found alone in a Gaucher disease-causing allele, when found in a double mutant such as [c.680A>G; c.1093G>A] ([p.N188S; p.E326K]) and [c.1448T>C; c.1093G>A] ([p.L444P; p.E326K]), decreases activity compared to the activity found for the other mutation alone. These results suggest that c.1093G>A (p.E326K) should be considered a "modifier variant" rather than a neutral polymorphism, as previously considered. Mutation c.680A>G (p.N188S), which produces a mutant enzyme with the highest level of activity, is probably a very mild mutation or another "modifier variant."     

Glial cell line-derived neurotrophic factor receptor alpha1 availability regulates glial cell line-derived neurotrophic factor signaling: evidence from mice carrying one or two mutated alleles

Glial cell line-derived neurotrophic factor receptor alpha1 (GFRalpha1, also known as GDNFR-alpha) is a glycolipid-anchored membrane protein of the GFRalpha family, which binds glial cell line-derived neurotrophic factor [Jing S. et al. (1996) Cell 85, 1113-1124; Treanor J. J. et al. (1996) Nature 382, 80-83], a survival factor for several populations of central and peripheral neurons, including midbrain dopamine neurons [Lin L. F. et al. (1993) Science 260, 1130-1132], and mediates its ligand-induced cell response via a tyrosine kinase receptor called Ret [Takahashi M. et al. (1988) Oncogene 3, 571-578; Takahashi M. and Cooper G. M. (1987) Molec. Cell Biol. 7, 1378-1385]. In this paper, we show that mice with a null mutation of the GFRalpha1 gene manifest epithelial-mesenchymal interaction deficits in kidney and severe disturbances of intestinal tract development similar to those seen with glial cell line-derived neurotrophic factor or Ret null mutations. There is a marked renal dysgenesis or agenesis and the intrinsic enteric nervous system fails completely to develop. We also show that newborn GFRalpha1-deficient mice display no or minimal changes in dorsal root and sympathetic ganglia. This is in contrast to the deficits reported in these neuronal populations in glial cell line-derived neurotrophic factor and Ret null mutations. Mesencephalic dopaminergic neurons in the substantia nigra and ventral tegmental area appear intact at the time of birth of the mutated mice. Mice homozygous for the GFRalpha1 null mutation die within 24 h of birth because of uremia. Heterozygous animals, however, live to adulthood. There is a significantly reduced neuroprotective effect of glial cell line-derived neurotrophic factor in such heterozygous animals, compared with wild-type littermates, after cerebral ischemia. Taken together with previous data on glial cell line-derived neurotrophic factor and Ret, our results strongly suggest that GFRalpha1 is the essential GFRalpha receptor for signaling in the glial cell line-derived neurotrophic factor-Ret pathway in the kidney and enteric nervous system development, and that GFRalpha2 or GFRalpha3 cannot substitute for the absence of GFRalpha1. Moreover, neuroprotective actions of exogenous glial cell line-derived neurotrophic factor also require full GFRalpha1 receptor expression.     

Effect of hyperventilation on brain tissue oxygenation and cerebrovenous PO2 in rats

Previous studies have shown that cortical tissue oxygenation is impaired during hyperventilation. However, it is important to quantify the effect of hyperventilation on brain tissue PO(2) and cerebrovenous PO(2) simultaneously especially since cerebral venous oxygenation is often used to assess brain tissue oxygenation. The present study was designed to measure the sagittal sinus PO(2) (PvO(2)), brain tissue PO(2) in the thalamus (PtO(2)), and brain temperature (Bt) simultaneously during acute hyperventilation. Isoflurane-anesthetized rats were hyperventilated for 10 min during which time the arterial carbon dioxide tension (PaCO(2)) dropped from 40.3+4.9 mmHg to 23.5+2.8 mmHg. PtO(2) declined from 26.0+/-4.2 mmHg to 14.8+/-5.2 mmHg (P=0.004) while brain temperature decreased from 36.5+0.3 degrees C to 36.2+0.3 degrees C (P=0.02). However, PvO(2) and arterial blood pressure (BP) did not change during hyperventilation. The maintenance of PvO(2) when perfusion is thought to decline and PtO(2) decreases suggests that there may be a diffusion limitation, possibly due to selective perfusion. Therefore, cerebrovenous PO(2) may not give a good assessment of brain tissue oxygenation especially in conditions of acute hyperventilation, and deeper brain regions other than the cortex also show impaired tissue oxygenation following hyperventilation.     

Energetics and Mechanism of Conformational Transitions of Protein‐Like NIPAM‐Sodium Styrene Sulfonate Copolymers in Aqueous Solutions

Protein‐like and random NIPAM‐sodium styrene sulfonate copolymers of similar composition have been prepared by radical polymerization in water at temperatures above and below the LCST of PNIPAM, respectively. Thermal transitions of the copolymers in aqueous solutions have been studied by means of dynamic light scattering, viscometry, and high‐sensitivity differential scanning calorimetry. The phase separation or cooperative conformational transitions without phase separation were observed for the random or the protein‐like copolymers, respectively. Transition temperature, enthalpy, and heat capacity increment of the protein‐like copolymer differed insignificantly from those of the random copolymer of similar composition. The transition heat capacity increments of the protein‐like copolymers revealed that only 10–20% of their NIPAM links participate in the formation of a dense water‐free globule core. The coil–globule transitions of the protein‐like copolymers were described by the thermodynamic three‐state model according to the scheme “random coil?condensed coil?globule”, which is known to simulate the folding mechanism of globular proteins.

     

New insights into the origin of the Gaucher disease-causing mutation N370S: extended haplotype analysis using the 5GC3.2, 5470 G/A, and ITG6.2 polymorphisms.

Gaucher disease is a lysosomal storage disorder inherited as an autosomal recessive trait. It is highly prevalent among Ashkenazi Jews but also present in other populations. Mutations in the glucocerebrosidase gene are the main cause of the disorder. One of these gene defects, N370S, is the most prevalent disease allele in the Ashkenazi Jewish patient population and also frequent in others, such as the Spanish and Portuguese Gaucher disease populations. Previous results based on haplotype analysis support the hypothesis of a single origin for this mutation. We have extended the haplotype analysis to include three newly described polymorphisms, 5GC3.2, ITG6.2 (very close to the gene), and 5470 G/A (in intron 7 of the GBA gene) in a sample of Spanish and Ashkenazi Jewish patients. The results confirm the single origin of the mutation in these two populations. The 5470A allele is only found in N370S chromosomes and was believed to be limited to the Portuguese population. Here we describe that it is also present with a similar frequency in Spain. Moreover, most of the 5470A alleles are found within particular haplotypes, which have some differences from the common N370S haplotype.