Multispectral analysis of magnetic resonance images

Magnetic resonance (MR) imaging systems produce spatial distribution estimates of proton density, relaxation time, and flow, in a two dimensional matrix form that is analogous to that of the image data obtained from multispectral imaging satellites. Advanced NASA satellite image processing offers sophisticated multispectral analysis of MR images. Spin echo and inversion recovery pulse sequence images were entered in a digital format compatible with satellite images and accurately registered pixel by pixel. Signatures of each tissue class were automatically determined using both supervised and unsupervised classification. Overall tissue classification was obtained in the form of a theme map. In MR images of the brain, for example, the classes included CSF, gray matter, white matter, subcutaneous fat, muscle, and bone. These methods provide an efficient means of identifying subtle relationships in a multi-image MR study.     

Xylitol enhances bacterial killing in the rabbit maxillary sinus

OBJECTIVES: Factors that alter airway surface liquid (ASL) ionic concentrations may influence the course of sinusitis. Xylitol has been shown to effect ASL ionic composition in vitro and to reduce nasal bacterial carriage, otitis media, and dental caries in vivo. We examined the effect of xylitol on experimental sinusitis in the rabbit model. STUDY DESIGN: Prospective randomized controlled study of xylitol, saline, and Pseudomonas aeruginosa administration to the rabbit maxillary sinus. METHODS: P. aeruginosa was administered to the sinuses of 26 New Zealand white rabbits. Saline was placed in the left maxillary sinus and xylitol in the right. The rabbits were randomly assigned to one of three groups: one, simultaneous administration of bacteria and solutions with bacterial analysis at 20 minutes, 11 rabbits; two, preadministration of solutions 1 hour before bacterial infection with analysis at 20 minutes, 11 rabbits; three, established sinusitis, 4 rabbits had daily injections of solutions for 5 days starting 7 days after P. aeruginosa administration. RESULTS: In group 1, 6.96% of injected bacteria were retrieved on the left (saline), whereas 0.095% were retrieved on the right (xylitol) (P = .034). In group 2, 5.64% of inoculum was recovered from the left and 2.89% from the right (P = .188). Group 3 demonstrated evidence of sinusitis with recovery of noninoculate bacteria. with no difference between right and left. CONCLUSIONS: Xylitol reduces experimental sinusitis when administered simultaneously with bacteria. Its effect in established sinusitis is less clear. A role may exist for xylitol in nasal irrigation fluid in human disease.     

Outcomes for children with submucous cleft palate and velopharyngeal insufficiency

OBJECTIVE: To review the outcomes of children with submucous cleft palate who also have velopharyngeal insufficiency (VPI). METHODS: A retrospective chart review was carried out at a tertiary care academic centre of all patients who had VPI with a submucous cleft palate. The University of Iowa Cleft Palate registry parameters encompassing nasality (hyper- and hyponasality) were compared pre- and postoperatively. RESULTS: Preliminary results demonstrate a significant, stable improvement in children who underwent palatal surgery for VPI. CONCLUSION: Positive outcomes in the treatment of VPI in the submucous cleft palate population were demonstrated with a combined approach of speech therapy and palatal surgery.     

Combined oral contraceptives do not influence post-exercise hypotension in women

The aim of the present study was to examine the pattern of cardiovascular recovery from exercise in 15 women (age, 20.3 +/- 1.4 years; body mass, 61.5 +/- 4.3 kg) across two phases of oral contraceptive (OC) use: 21 days of consumption and 7 days of withdrawal. Cardiovascular recovery was measured in the supine position for 60 min following 30 min of exercise at 60% maximal rate of oxygen consumption (VO2,max). Central and peripheral haemodynamics were assessed during consumption and withdrawal of the OC pill using occlusion plethysmography, Doppler flowmetry and echocardiography. Significant hypotension occurred following exercise (P < 0.05), returning to baseline values after 60 min. The peak hypotension occurred 5 min into recovery. Cardiac output and heart rate were elevated for 60 min following exercise (P < 0.05), whilst stroke volume remained at baseline values. Heart rate was greater throughout recovery during consumption compared to withdrawal (P < 0.05); however, although there was a trend for greater responses during consumption, phase of OC use did not affect the other central cardiovascular variables (P > 0.05). Post-exercise blood flow parameters were not significantly affected by exercise or OC phase; however, calf blood flow was greater, and resistance to flow lower during consumption (P > 0.05). The pattern of post-exercise fluctuations in cardiovascular parameters may differ from those seen in men, whilst oestrogen variation may influence research findings.     

Tracheal spindle cell tumor in a child

Tracheal tumors in the pediatric population are rare neoplasms that have devastating consequences if not evaluated and diagnosed in a timely fashion. As illustrated by this case, the tumors typically do not become symptomatic until marked airway obstruction occurs, and patients may present with acute respiratory distress. Radiologic advances, including 3-D CT tracheal reconstruction, are invaluable in the diagnosis of and surgical planning for tracheal neoplasms.     

GJB2 gene mutations causing familial hereditary deafness in Turkey

Mutations in Connexin 26 (Cx26) play an important role in autosomal non-syndromic hereditary hearing loss. In this study, our objective was to find out the significance of Cx26 mutations in Turkish families who had hereditary deafness. Fourteen families who had at least two prelingually deaf children per family were included in the study. One affected child from each of the 14 families was selected for single-stranded conformational polymorphism SSCP analysis. Three PCR reactions were used for each subject to amplify the entire Cx26 coding region with overlap. PCR products were sequenced on an Applied Biosystems (ABI) model 3700 automated sequencer. Six of the 14 representative family members (42.9%) demonstrated shifts on SSCP and were subsequently sequenced for Exons 1 and 2 of GJB2 and were tested for the 432 kb upstream deletion. No mutations were found in Exon 1 and no 432 kb deletions were noted. Three different GJB2 mutations were found in Exon 2 of the probands, which were 35delG, 299-300delAT, and 487G > A (M163V). GJB2 mutations were detected in 21.4% of the families. Two patients were homozygous for 35delG and 299-300delAT mutations, and were given a diagnosis of DFNB1 deafness (14.3%). Two different polymorphisms, 457G > A (V153I) and 380G > AG (R127H) were also found. In conclusion, although GJB2 mutations were detected in 21.4% of the families tested, only 14.3% of subject representatives were homozygous and therefore deafness caused by Cx26 mutation segregated with DFNB1. Thus, contribution of GJB2 mutations appears less significant in familial deafness. This necessitates further assessment for the other known gene regions as well as a search for new genetic factors in familial type of genetic deafness.     

Enhancing causal interpretations of quality improvement interventions

In an era of chronic resource scarcity it is critical that quality improvement professionals have confidence that their project activities cause measured change. A commonly used research design, the single group pre-test/post-test design, provides little insight into whether quality improvement interventions cause measured outcomes. A re-evaluation of a quality improvement programme designed to reduce the percentage of bilateral cardiac catheterisations for the period from January 1991 to October 1996 in three catheterisation laboratories in a north eastern state in the USA was performed using an interrupted time series design with switching replications. The accuracy and causal interpretability of the findings were considerably improved compared with the original evaluation design. Moreover, the re-evaluation provided tangible evidence in support of the suggestion that more rigorous designs can and should be more widely employed to improve the causal interpretability of quality improvement efforts. Evaluation designs for quality improvement projects should be constructed to provide a reasonable opportunity, given available time and resources, for causal interpretation of the results. Evaluators of quality improvement initiatives may infrequently have access to randomised designs. Nonetheless, as shown here, other very rigorous research designs are available for improving causal interpretability. Unilateral methodological surrender need not be the only alternative to randomised experiments.     

Quality of outcome and cost in an obstetric and neonatal service

A review has been made of the outcome and efficiency of the obstetric and neonatal service, St Helen's Hospital, Auckland. In the last seven years there has been a 33% fall in perinatal mortality rates to 5.88 per 1000 births in 1987. The average perinatal death rate for Maori infants was low, 4.81 per 1000 compared to 7.43 per 1000 for Europeans over this period. There has been a 38% increase in births to 3597 a year while the total hospital staffing has only risen 9%. Thus the ratio of births to staff has increased by 26.6% to 15.6. The cost per infant delivered in constant dollars has fallen 18.7% in the same period to $2432. The postnatal bed occupancy was 101% in 1987 and the average day stay fell to 5.7 days. An extra 61 full time staff would be needed to reduce the workload to that of 1981 and the staff is now unable to give the family focused holistic care that is needed.