Confirming nasal airway dimensions observed on panoramic and posterior-anterior cephalometric radiographs using an acoustic rhinometer

AIM

This study aimed to confirm the nasal airway dimensions observed in standard dental radiographs through analysis of the anterior nasal cross-sectional area and nasal volume with acoustic rhinometry.

METHOD

Participants were chosen from the patient population under consideration for interceptive orthodontic treatment at Tufts University's Pediatric Dentistry Clinic. A total of 55 Caucasian subjects, of both sexes (males=28, females =27), and ranging from age 6-9 years (mean= 7.33) were enrolled. Utilizing the ImageJ program, the subjects' panoramic and PA cephalometric radiographs were analyzed for radiolucent anterior nasal cross-sectional area. Subjects were then examined with the Eccovision Acoustic Rhinometer, which measured anterior nasal cross-sectional area and nasal volume. Data were grouped together, and areas and volume gathered from the radiographs and rhinometer analyzed for any correlation. Statistical analysis was performed using the SPSS program. Data was further divided into right and left nasal side, and a Pearson Correlation Matrix was created for 8 predictor variables (right and left panoramic area, right and left cephalometric area, right and left rhinometer area, and right and left rhinometer volume).

RESULTS

Values in this correlation matrix ranged from 0.712 to 0.988; all were statistically significant at the <0.01 level (2-tailed test).

CONCLUSION

A very strong correlation was found between the anterior nasal cross-sectional area calculated from the radiographs, and the anterior nasal cross-sectional area and nasal volume from the rhinometer.

Degradation of eschar from venous leg ulcers using a recombinant chymotrypsin from Lucilia sericata

BACKGROUND

Larvae of the greenbottle Lucilia sericata are used to debride nonhealing wounds and stimulate the production of fresh granulation tissue. Previous publications have shown that secretions from L. sericata contain a number of proteolytic activities including a chymotrypsin that degrades a number of extracellular matrix components such as fibronectin, laminin and collagen.

OBJECTIVES

To produce a recombinant L. sericata chymotrypsin (chymotrypsin I) and determine its effects on the degradation of patient wound eschar.

METHODS

An active recombinant chymotrypsin I from L. sericata was cloned and expressed in Sf9 cells and its subsequent effects ex vivo on eschar from venous leg ulcers were determined by two-dimensional electrophoresis.

RESULTS

The recombinant enzyme had the attributes of a chymotrypsin, possessing sequence homology with other chymotrypsins and demonstrating attributes of the native enzyme including cleavage of the chymotrypsin substrate succinyl-alanyl-alanyl-prolyl-phenylalanyl-7-amino-4-methyl coumarin, inhibition by phenylmethylsulphonyl fluoride and lack of inhibition by amidinophenylmethylsulphonyl fluoride. Importantly, the recombinant chymotrypsin cleaved the majority of proteins from slough/eschar from venous leg ulcers in a superior manner to chymotrypsins from human and bovine sources.

CONCLUSIONS

The ex vivo degradation of eschar from venous leg ulcers indicates the potential value of recombinant chymotrypsin I as a novel, stand-alone debridement agent.

Maize chloroplast DNA fragment encoding the large subunit of ribulosebisphosphate carboxylase

In vitro linked transcription-translation of chloroplast DNA has been used to show that the large subunit of ribulose-1,5-bisphosphate carboxylase [3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39] is encoded by Zea mays chloroplast DNA. A BamHI-generated chloroplast DNA sequence cloned in Escherichia coli is shown to direct the in vitro synthesis of this protein identified as large subunit by its size, serological properties, and limited proteolytic digestion products.

The effects of single dose anxiolytic medication on the CO2 models of anxiety: differentiation of subjective and objective measures

This was a double blind, placebo-controlled, 4-way cross-over study in 12 healthy volunteer subjects of the acute effects of three drugs each of which are used in the clinic to treat some forms of anxiety: propranolol 40 mg, hydroxyzine 25 mg, flupentixol 0.5 mg and placebo. Each test session consisted of inhalation of air for 20 min, 10-min rest, inhalation of CO2 7.5% for 20 min, 10-min rest, followed by a single vital capacity inhalation of 35% CO2. The CO2 7.5% was administered at peak drug effect. Subjective effects were measured using Visual Analogue Scales (VAS), the Panic Symptom Inventory and the Generalised Anxiety Disorder Assessment inventory. Twelve subjects participated (eight men), with a mean age of 25.9 years. The expected subjective effects of CO2 were seen and these were significantly different from effects of peak air. However, there were no statistically significant differences between the drugs or between drugs and placebo, indeed there was a trend for some VAS anxiety scores to be higher than placebo in the drug groups. There were some significant differences in cardiovascular responses to CO2, with propranolol significantly decreasing heart rate and flupentixol increasing blood pressure when compared with placebo. The lack of subjective anxiolytic actions of the three drugs contrasts with our previous findings with acute benzodiazepines and chronic selective serotonin reuptake inhibitor administration. It may be that prolonged treatment with these agents would be required to show anxiolytic effects, although it may also be that their efficacy is insufficient to be demonstrated in this model. The lack of anxiolytic actions of propranolol, despite a significant reduction in heart rate, is a further support for a central action of CO2 to produce anxiety.

End-of-life care in hospital: a descriptive study of all inpatient deaths in 1 year

The objectives of this study are to ascertain how many patients who died in a district general hospital in England might have been able to be cared for at home, to obtain the cost of each inpatient stay, to make an estimate of the maximum resource implications of care packages for these patients, and to calculate the savings in hospital admissions that could be used for the development of community services. These objectives are dependant on full implementation of the End of Life Strategy. A descriptive study of all inpatient deaths in one year in a district general hospital in the south west of England was conducted. Data collection - case notes of all patients who died at the hospital from the beginning of June 2006 to end of May 2007. A total of 599 case notes of 627 patients who died in the study period were reviewed. A total of 331 patients (56%) were not assessed as being in the last year of life. Of the remaining 44%, 152 (26%) were clearly in the last year of life and 110 (18%) had significant co-morbidities and could probably have been recognised as being in the last year of life. A total of 399 (67%) of patients were appropriately admitted to hospital for their final illness, 194 (33%) could have been looked after at home. At least 119 (20%) clearly and 75 (13%) probably could have stayed at home. The mean cost of admission was 3173 pound per patient. A total of 77 (13%) of patients were admitted from nursing homes and 53 (69%) of these could have stayed in the nursing home to die. A total of 44% of all patients who died within the district general hospital had chronic life threatening illnesses. A maximum of one third of all hospital deaths could have been looked after at home if excellent end of life services were in place. When commissioning end of life care services, it is possible to calculate how many extra patients may need community care packages and the cost that could be redistributed from hospital to community for these services.

A new high-content model system for studies of gastrointestinal transit: the zebrafish

The zebrafish gastrointestinal (GI) tract displays an anatomy and cellular architecture that is similar to the human GI tract, with concentric layers of inner epithelia, connective tissue, circular muscle and outer longitudinal muscle layers. Propulsion of luminal content results from the integrated activity of smooth muscle cells, enteric neurons and the interstitial cells of Cajal (ICC). Zebrafish larvae are transparent and propagating contractions in the entire GI tract are easily visualized. A new moderate-throughput zebrafish-based GI transit assay is described in this issue of Neurogastroenterology and Motility. This assay utilizes intact zebrafish larvae which contain essential regulatory elements (ICC and enteric neurons). Forward genetic analysis, which identifies genes underlying specific phenotypes, is possible using the zebrafish system. The zebrafish model system compliments existing models for studies of GI motility and will contribute to the understanding of the regulation of GI motility, and to identification of novel drug targets.

Kit-like immunoreactivity in the zebrafish gastrointestinal tract reveals putative ICC

Gastrointestinal (GI) motility results from the coordinated actions of enteric neurons, interstitial cells of Cajal (ICC), and smooth muscle cells. The GI tract of the zebrafish has a cellular anatomy that is essentially similar to humans. Although enteric nerves and smooth muscle cells have been described, it is unknown if ICC are present in the zebrafish. Immunohistochemistry and PCR were used determine expression for the zebrafish Kit orthologue in the zebrafish gastrointestinal tract. Cells displaying Kit-like immunoreactivity were identified in the muscular layers of the adult zebrafish gastrointestinal tract. Two layers of Kit-positive cells were identified, one with multipolar cells located between the longitudinal and circular smooth muscle layers and one with simple bipolar cells located deep in the circular muscle layer. Primers specifically designed to amplify mRNA coding for two zebrafish kit genes, kita and kitb, and two kit ligands, kitla and kitlb, amplified the expected transcript from total RNA isolated from zebrafish GI tissues. The Sparse mutant, a kita null mutant, showed reduced contraction frequency and increased size of the GI tract indicating a functional role for kita. These data establish the presence of a cellular network with Kit-like immunoreactivity in the myenteric plexus region of the zebrafish GI tract, adjacent to enteric neurons. Expression of kita and kitb, and the ligands kitla and kitlb, were verified in the adult GI tract. The anatomical arrangement of the Kit-positive cells strongly suggests that they are ICC.

How to care for uncomplicated skin and keep it free of complications

Many of the skin problems associated with lymphoedema and other chronic oedemas can be reduced or even prevented with appropriate and effective skin care. In particular, the use of emollients to maintain skin condition and integrity can reduce the frequency and severity of cellulitic episodes. This article describes best practice in the care of the skin in cases of uncomplicated lymphoedema.

Why RNA and DNA have different structures

In the early years of molecular biology--over 50 years ago--we were faced with many unknowns. A significant one at the time was the relationship between DNA and RNA, both in terms of structure and function. Function is often a reflection of structure. Here I outline some of the early research in this area, especially for RNA structure, which was completely unknown when we started.

Kit/stem cell factor receptor-induced phosphatidylinositol 3'-kinase signalling is not required for normal development and function of interstitial cells of Cajal in mouse gastrointestinal tract

Signalling mediated by the receptor tyrosine kinase c-Kit is required for normal development of interstitial cells of Cajal (ICC). c-Kit activates several signalling pathways, including the phosphatidylinositol 3'-kinase (PI3'-kinase) pathway. The signals required for ICC development and maintenance are not well understood. Studies indicate a role for PI3'-kinase. We studied ICC function and morphology in mice homozygous for the tyrosine 719 to phenylalanine c-Kit mutation, which disrupts all PI3'-kinase binding to c-Kit. Functionally, the electrical slow waves in the jejunum and inhibitory junction potentials were normal in adult mutants. Morphologically, the distribution of ICC was not altered in mutants. There was no difference in the density of ICC in the jejunum of adults or newborns from quantitative analysis of c-Kit immunoreactivity. The number of ICC obtained in culture was the same using mutants or wild-type littermates. The density and organization of nerves in the jejunum of mutants was not affected. Deletion of c-Kit-induced PI3'-kinase signalling does not affect the function or development of ICC in the mouse. This is an important and counterintuitive result, given the role of PI3'-kinase signalling downstream of c-Kit and the role of both c-Kit and PI3'-kinase individually in ICC development.