Paediatric mandibular fracture-a diagnostic challenge?

The purpose of this study was to clarify the frequency of missed mandibular fractures and to identify possible predictive factors for missed diagnosis. This was a retrospective study that included patients <20 years of age with a recent mandibular fracture. The outcome variable was missed mandibular fracture, which was determined when a fracture was not suspected or diagnosed during the patient's first assessment in primary healthcare. The primary predictor variable was age group (i.e. children <13 years or teenagers/adolescents aged 13-19 years). The explanatory variables were sex, mechanism of injury, and type of facial facture. Other variables were clinical symptoms and findings. Mandibular fracture was missed at first contact in 27 of 182 patients (14.8%). Fracture was missed significantly more often in patients <13 years than in older patients (33.3% vs. 8.8%, P<0.001). The only significant symptom or clinical finding that was associated with missed fractures was skin wound of the jaw (P=0.009). There was no association between missed fracture and sex or mechanism of injury. Mandibular fractures in children are often missed at the first healthcare contact. Careful examination is necessary in paediatric mandibular injuries, particularly in the youngest age groups. Consultation should be smooth between paediatric trauma units and maxillofacial surgeons.

Does postoperative orbital volume predict postoperative globe malposition after blow-out fracture reconstruction? A 6-month clinical follow-up study.

PURPOSE: The aim of this study was to investigate the relationship between intraorbital volume change caused by orbital fracture and globe malposition (GMP) in blow-out fracture patients undergoing surgery and to clarify the significance of different radiologically detected predictors associated with GMP. PATIENTS AND METHODS: A 6-month prospective follow-up study of unilateral isolated orbital fractures was designed and implemented. The main outcome variable was GMP (present or absent); the secondary outcome was orientation of GMP (horizontal or vertical). The primary predictor variable was postoperative orbital volume difference determined as the difference between the fractured and non-fractured orbit (measured in milliliter and analyzed in milliliter and percentages). The explanatory variables were gender, age, treatment delay from trauma to surgery, fracture site, horizontal depth of the fracture, fracture area, maximum vertical dislocation of the fracture, and preoperative volume difference. RESULTS: A total of 15 patients fulfilled the inclusion criteria and were followed for 6 months from a larger cohort. GMP was detected in 6/15 patients (40.0%). GMP was more often present in large (≥ 2.5 cm2) fractures (55.6%), in combined orbital fractures (50.0%), and in fractures with preoperative volume difference ≥ 2.5 ml (62.5%) regardless of the postoperative volume correction. Postoperatively, patients with and without GMP displayed overcorrection of orbital volume; 4.15% corresponded to 1.15 ml (with GMP) and 7.6% corresponded to 1.9 ml (without GMP). CONCLUSION: GMP was present in large and combined orbital fractures. Clinically detectable postoperative GMP occurred despite satisfactory orbital reconstruction and overcorrection. Mild GMP, however, is not significant for the patient.

Effect of age and body weight on neurohumoral variables in healthy Cavalier King Charles spaniels.

OBJECTIVE: To evaluate the effect of age and body weight on several neurohumoral variables that are commonly altered in heart failure in Cavalier King Charles Spaniels. ANIMALS: 17 healthy privately owned Cavalier King Charles Spaniels, 10 males and 7 females, ranging in age from 0.4 to 9.7 years, and ranging in body weight from 6.6 to 12.2 kg. PROCEDURE: The clinical condition of the dogs was evaluated by physical examination, thoracic radiography, and echocardiography. Plasma nitrate and nitrite (P-NN), N-terminal atrial natriuretic and brain natriuretic peptides (NT-ANP and BNP, respectively), endothelin (ET-1), urine cyclic guanosine monophosphate (U-cGMP), and urine nitrate and nitrite (U-NN) concentrations were analyzed. RESULTS: Plasma concentrations of NT-ANP and P-NN increased significantly with age, but plasma NT-ANP and P-NN also correlated significantly, irrespective of age. A modest increase of left atrial size did not explain the increase of NT-ANP and P-NN with age. Concentration of ET-1 correlated positively with heart rate; heart rate did not change with age. Weight had a negative impact on NT-ANP, P-NN, and U-cGMP concentrations and left atrial relative size. CONCLUSIONS AND CLINICAL RELEVANCE: Age-matched controls are essential for evaluation of NT-ANP and P-NN concentrations and left atrial size. Weight may alter reference values of plasma NT-ANP, P-NN, and urine cGMP concentrations. Natriuretic peptides can be used as further evidence that heart failure exists. The increased plasma concentrations of NT-ANP (but not BNP) and P-NN with aging reflect neurohumoral physiologic changes that must be distinguished from pathologic changes in patients with heart failure.

Conversion of xylose to ethanol by recombinant Saccharomyces cerevisiae: importance of xylulokinase (XKS1) and oxygen availability.

The yeast Saccharomyces cerevisiae efficiently ferments hexose sugars to ethanol, but it is unable to utilize xylose, a pentose sugar abundant in lignocellulosic materials. Recombinant strains containing genes coding for xylose reductase (XR) and xylitol dehydrogenase (XDH) from the xylose-utilizing yeast Pichia stipitis have been reported; however, such strains ferment xylose to ethanol poorly. One reason for this may be the low capacity of xylulokinase, the third enzyme in the xylose pathway. To investigate the potential limitation of the xylulokinase step, we have overexpressed the endogenous gene for this enzyme (XKS1) in S. cerevisiae that also expresses the P. stipitis genes for XR and XDH. The metabolism of this recombinant yeast was further investigated in pure xylose bioreactor cultivation at various oxygen levels. The results clearly indicated that overexpression of XKS1 significantly enhances the specific rate of xylose utilization. In addition, the XK-overexpressing strain can more efficiently convert xylose to ethanol under all aeration conditions studied. One of the important illustrations is the significant anaerobic and aerobic xylose conversion to ethanol by the recombinant Saccharomyces; moreover, this was achieved on pure xylose as a carbon. Under microaerobic conditions, 5.4 g L(-1) ethanol was produced from 47 g L(-1) xylose during 100 h. In fed-batch cultivations using a mixture of xylose and glucose as carbon sources, the specific ethanol production rate was highest at the highest aeration rate tested and declined by almost one order of magnitude at lower aeration levels. Intracellular metabolite analyses and in vitro enzyme activities suggest the following: the control of flux in a strain that overexpresses XKS1 has shifted to the nonoxidative steps of the pentose phosphate pathway (i.e., downstream of xylose 5-phosphate), and enzymatic steps in the lower part of glycolysis and ethanol formation pathways (pyruvate kinase, pyruvate decarboxylase, and alcohol dehydrogenase) do not have a high flux control in this recombinant strain. Furthermore, the intracellular ATP levels were found to be significantly lower for the XK strain compared with either the control strain under similar conditions or glucose-grown Saccharomyces. The ATP : ADP ratios were also lower for the XK strain, especially under microaerobic conditions (0.9 vs 6.4).

Ethanol inhibits IgE-induced degranulation and cytokine production in cultured mouse and human mast cells.

Activated mast cells (MC) can produce a wide variety of potent inflammatory mediators. Excessive alcohol consumption is known to lead to immune deficiency and propensity for pneumonias in particular. As MCs are important in the first line of defence of mucosal membranes we have studied the effect of ethanol (EtOH) on several MC functions. EtOH attenuated dose dependently IgE-induced degranulation of mouse bone marrow derived mast cells (mBMMC) as reflected by the release of granule associated beta-hexosaminidase (beta-hex). A mean of 26 +/- 7% inhibition of beta-hex release was observed in the presence of 5/1000 (86 mM) EtOH and nearly complete inhibition in the presence of 20/1000 (344 mM) ethanol. The IgE-induced degranulation of mBMMC cultured with EtOH for seven days was inhibited to a similar degree as the degranulation of mBMMC exposed to EtOH for only one hour. Inclusion of 5/1000 (86 mM) ethanol in the medium reduced tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 production in human mast cell line (HMC-1) cells by 55 +/- 7% and 19 +/- 5%, respectively, and the presence of 20/1000 (344 mM) ethanol inhibited the expression 81 +/- 12% and 59 +/- 14% respectively. These results suggest that, in contrast to previous assumption, ethanol inhibits several critical MC functions at least in vitro. This inhibition of mediator, and cytokine release in particular, could contribute to the immune deficiency associated with chronic alcohol consumption.

The role of xylulokinase in Saccharomyces cerevisiae xylulose catabolism.

Many yeast species have growth rates on D-xylulose of 25-130% of those on glucose, but for Saccharomyces cerevisiae this ratio is only about 6%. The xylulokinase reaction has been proposed to be the rate-limiting step in the D-xylulose fermentation with S. cerevisiae. Over-expression of xylulokinase encoding XKS1 stimulated growth on D-xylulose in a S. cerevisiae strain to about 20% of the growth rate on glucose and deletion of the gene prevented growth on D-xylulose and D-xylulose metabolism. We have partially purified the xylulokinase and characterised its kinetic properties. It is reversible and will also accept D-ribulose as a substrate.

Evidence that the gene YLR070c of Saccharomyces cerevisiae encodes a xylitol dehydrogenase.

The open reading frame YLR070c of Saccharomyces cerevisiae has high sequence similarity to S. cerevisiae sorbitol dehydrogenase and to xylitol dehydrogenase of Pichia stipitis. Overexpression of this open reading frame in S. cerevisiae resulted in xylitol dehydrogenase activity. The enzyme is specific for NADH. The following Michaelis constants were estimated: D-xylulose, 1.1 mM; NADH, 240 microM (at pH 7.0); xylitol, 25 mM; NAD, 100 microM (at pH 9.0). Xylitol dehydrogenase activity with the same kinetic properties can also be induced by xylose in wild type S. cerevisiae cells.

Identification and quantitation of phosphorus metabolites in yeast neutral pH extracts by nuclear magnetic resonance spectroscopy.

(31)P NMR spectroscopy offers a possibility to obtain a survey of all low-molecular-weight phosphorylated compounds in yeast. The yeast cells have been extracted using chloroform into a neutral aqueous phase. The use of high fields and the neutral pH extracts, which are suitable for NMR analysis, results in well-resolved (31)P NMR spectra. Two-dimensional NMR experiments, such as proton-detected heteronuclear single quantum ((1)H-(31)P HSQC) and (31)P correlation spectroscopy ((31)P COSY), have been used to assign the resonances. In the phosphomonoester region many of the signals could be assigned to known metabolites in the glycolytic and pentose phosphate pathways, although some signals remain unidentified. Accumulation of ribulose 5-phosphate, xylulose 5-phosphate, and ribose 5-phosphate was observed in a strain lacking transketolase activity when grown in synthetic complete medium. No such accumulation occurred when the cells were grown in yeast-peptone-dextrose medium. Trimetaphosphate (intracellular concentration about 0.2 mM) was detected in both cold methanol-chloroform and perchloric acid extracts.