Are low-energy open ankle fractures in the elderly the new geriatric hip fracture?

As the geriatric population in the United States continues to increase, ankle fractures in the elderly are predicted to exponentially increase in the future. As such, these injuries will become a common injury seen by physicians in various fields. Currently, no studies discussing low-energy open ankle fractures in the elderly and/or the mortality rate associated with these devastating injuries have been published. The purpose of the present study was to retrospectively review the morality rate associated with low-energy open ankle fractures in the elderly. We retrospectively identified 11 patients >60 years old who had sustained low-energy open ankle fractures and been treated at our institution. The patient demographics, mechanism of injury, wound size, medical comorbidities, treatment, follow-up data, and outcomes were recorded. Low-energy falls were defined as ground level falls from sitting or standing. The mean age of the patients was 70.72 years, with a mean body mass index of 35.93 ± 10.24. Of the 11 patients, 9 (81.81%) had ≥3 comorbidities (i.e., hypertension, diabetes, coronary artery disease, congestive heart failure, and/or chronic obstructive pulmonary disease). The mean size of the medially based ankle wound was 14.18 ± 4.12 cm; 10 (90.90%) were Gustilo and Anderson grade IIIA open ankle fractures. In our study, low-energy open ankle fractures in the elderly, very similar to hip fractures, were associated with a high mortality incidence (27.27%) at a mean of 2.67 ± 2.02 months, and 81.81% of our patients had ≥3 medical comorbidities.

Molecular architecture of myelinated peripheral nerves is supported by calorie restriction with aging

Peripheral nerves from aged animals exhibit features of degeneration, including marked fiber loss, morphological irregularities in myelinated axons and notable reduction in the expression of myelin proteins. To investigate how protein homeostatic mechanisms change with age within the peripheral nervous system, we isolated Schwann cells from the sciatic nerves of young and old rats. The responsiveness of cells from aged nerves to stress stimuli is weakened, which in part may account for the observed age-associated alterations in glial and axonal proteins in vivo. Although calorie restriction is known to slow the aging process in the central nervous system, its influence on peripheral nerves has not been investigated in detail. To determine if dietary restriction is beneficial for peripheral nerve health and glial function, we studied sciatic nerves from rats of four distinct ages (8, 18, 29 and 38 months) kept on an ad libitum (AL) or a 40% calorie restricted diet. Age-associated reduction in the expression of the major myelin proteins and widening of the nodes of Ranvier are attenuated by the dietary intervention, which is paralleled with the maintenance of a differentiated Schwann cell phenotype. The improvements in nerve architecture with diet restriction, in part, are underlined by sustained expression of protein chaperones and markers of the autophagy-lysosomal pathway. Together, the in vitro and in vivo results suggest that there might be an age-limit by which dietary intervention needs to be initiated to elicit a beneficial response on peripheral nerve health.

Identification and isolation of CD1a positive putative tumour infiltrating dendritic cells in human breast cancer

Identification of dendritic cells (DC) in human tissues has been technically problematic due to the lack of truly specific immunohistochemical markers for DC's. Human dendritic cells express CD1a glycoprotein at certain points in their life cycle. CD1a positive cells are present in many human tumours and have been associated with improved survival. However, little information exists concerning the separation of DC from human tumours. The current study reports that human breast carcinomas have low densities of CD1a positive cells with dendritic morphology, and details are shown of a technique for successful separation of these cells from tumour tissues.

Identification of the enzyme responsible for oxidative halothane metabolism: implications for prevention of halothane hepatitis

BACKGROUND

Fulminant hepatic necrosis ("halothane hepatitis") is an unusual and often fatal complication of halothane anaesthesia. It is mediated by immune sensitisation in susceptible individuals to trifluoroacetylated liver protein neoantigens, formed by oxidative halothane metabolism. The seminal event in halothane hepatitis is hepatic metabolism, yet the enzyme responsible for oxidative halothane metabolism and trifluoroacetylated neoantigen formation remains unidentified. This investigation tested the hypothesis that cytochrome P450 2E1 (CYP2E1) is responsible for human halothane metabolism in vivo.

METHODS

20 elective surgical patients received either disulfiram (500 mg orally, n = 10) or nothing (controls, n = 10) the night before surgery. Disulfiram, converted in vivo to an effective inhibitor of P450 2E1, was used as a metabolic probe for P450 2E1. All patients received standard halothane anaesthesia (1.0% end-tidal, 3 h). Blood halothane and plasma and urine trifluoroacetic acid, bromide, and fluoride concentrations were measured for up to 96 h postoperatively.

FINDINGS

Total halothane dose, measured by cumulative end-tidal (3.8 SE 0.1 minimum alveolar concentration hours) and blood halothane concentrations, was similar in the two groups. Plasma concentrations and urinary excretion of trifluoroacetic acid and bromide, indicative of oxidative and total (oxidative and reductive) halothane metabolism, respectively, were significantly diminished in disulfiram-treated patients. In control and disulfiram-treated patients cumulative 96 h postoperative trifluoroacetic acid excretion was 12,900 (SE 1700) and 2010 (440) mumol, respectively (p < 0.001) while that of bromide was 1720 (290) and 160 (70) mumol (p < 0.001).

INTERPRETATION

The substantial attenuation of trifluoroacetic acid production by disulfiram after halothane anaesthesia suggests that P450 2E1 is a predominant enzyme responsible for human oxidative halothane metabolism. Inhibition of P450 2E1 by a single preoperative oral disulfiram dose greatly diminished production of the halothane metabolite responsible for the neoantigen formation that initiates halothane hepatitis. Single-dose disulfiram may provide effective prophylaxis against halothane hepatitis.

Expression of a constitutively active erythropoietin receptor in primary hematopoietic progenitors abrogates erythropoietin dependence and enhances erythroid colony-forming unit, erythroid burst-forming unit, and granulocyte/macrophage progenitor growth

We tested the ability of a constitutively activated erythropoietin receptor [EpoR(R129C)] to alter the growth requirements of primary hematopoietic precursors that terminally differentiate in culture. Two recombinant retroviruses expressing EpoR(R129C), spleen focus-forming virus (SFFVc-EpoR) and myeloproliferative sarcoma virus (MPSVcEpoR), were used to infect fetal liver cells that served as a source of hematopoietic progenitors. Methylcellulose cultures were incubated in the absence of any added growth factors or in combination with selected growth factors. EpoR(R129C) completely abrogated the Epo requirement of erythroid colony-forming units to form erythrocytes after 2-5 days in culture and did not interfere with the differentiation program of these cells. In the absence of added growth factors EpoR(R129C) did not enhance erythroid burst-forming unit development. In contrast to experiments in heterologous cell lines, EpoR(R129C) did not render progenitor cells independent of interleukin 3 or granulocyte/macrophage colony-stimulating factor (GM-CSF). However, when progenitors were cultured with added steel factor, but not with interleukin 3 or GM-CSF, EpoR(R129C) augmented the growth and differentiation of erythroid bursts, mixed erythroid/myeloid, and granulocyte/macrophage (GM) colonies. Furthermore, both viruses were capable of expressing EpoR(R129C) in erythroid, mixed erythroid/myeloid, and GM colonies. Thus an aberrantly expressed and constitutively activated EpoR can stimulate proliferation of some GM progenitors. The ability of EpoR(R129C) to abrogate the Epo requirement of primary hematopoietic cells, but not the requirement for other cytokines, is consistent with the induction of erythroblastosis in vivo.

Pulmonary function in identical twins raised apart

As part of the Minnesota Study of Twins Raised Apart, we measured pulmonary function in 15 pairs of monozygotic twins and one set of monozygotic triplets who were separated at an average age of 3.8 months. Six pairs of twins were concordant for nonsmoking, 3 pairs and the triplets were concordant for cigarette smoking, and 6 pairs were discordant for respiratory problems (5 pairs for smoking, 1 pair for asthma). Thirteen pulmonary function tests were done on each twin; however, only 2 tests of pulmonary function, the FEF25-75% and V75, could separate smokers from nonsmokers to a statistically significant degree. One additional test, the FEV1, was the most sensitive way to separate smoking from nonsmoking twins when only paired data from twin pairs discordant for smoking were used. Intratwin differences between twins of a pair for these three pulmonary function tests were small and virtually identical for both concordant groups, whereas the intratwin differences in the discordant group were large and distinctly different from the concordant groups. These results, together with those of previous studies in identical twins raised together, support the conclusion that genetic factors are important in determining susceptibility to airway obstruction from cigarette smoke.