Determinants of lung disease progression measured by lung clearance index in children with cystic fibrosis

The lung clearance index (LCI) measured by the multiple breath washout (MBW) test is sensitive to early lung disease in children with cystic fibrosis. While LCI worsens during the preschool years in cystic fibrosis, there is limited evidence to clarify whether this continues during the early school age years, and whether the trajectory of disease progression as measured by LCI is modifiable.A cohort of children (healthy and cystic fibrosis) previously studied for 12 months as preschoolers were followed during school age (5-10 years). LCI was measured every 3 months for a period of 24 months using the Exhalyzer D MBW nitrogen washout device. Linear mixed effects regression was used to model changes in LCI over time.A total of 582 MBW measurements in 48 healthy subjects and 845 measurements in 64 cystic fibrosis subjects were available. The majority of children with cystic fibrosis had elevated LCI at the first preschool and first school age visits (57.8% (37 out of 64)), whereas all but six had normal forced expiratory volume in 1 s (FEV₁) values at the first school age visit. During school age years, the course of disease was stable (-0.02 units·year^-1 (95% CI -0.14-0.10). LCI measured during preschool years, as well as the rate of LCI change during this time period, were important determinants of LCI and FEV_1, at school age.Preschool LCI was a major determinant of school age LCI; these findings further support that the preschool years are critical for early intervention strategies.

Lung Clearance Index to Track Acute Respiratory Events in School-Age Children with Cystic Fibrosis

Rationale: The lung clearance index (LCI) is responsive to acute respiratory events in preschool children with cystic fibrosis (CF), but its utility to identify and manage these events in school-age children with CF is not well defined.Objectives: To describe changes in LCI with acute respiratory events in school-age children with CF.Methods: In a multisite prospective observational study, the LCI and FEV₁ were measured quarterly and during acute respiratory events. Linear regression was used to compare relative changes in LCI and FEV₁% predicted at acute respiratory events. Logistic regression was used to compare the odds of a significant worsening in LCI and FEV₁% predicted at acute respiratory events. Generalized estimating equation models were used to account for repeated events in the same subject.Measurements and Main Results: A total of 98 children with CF were followed for 2 years. There were 265 acute respiratory events. Relative to a stable baseline measure, LCI (+8.9%; 95% confidence interval, 6.5 to 11.3) and FEV₁% predicted (-6.6%; 95% confidence interval, -8.3 to -5.0) worsened with acute respiratory events. A greater proportion of events had a worsening in LCI compared with a decline in FEV₁% predicted (41.7% vs. 30.0%; P = 0.012); 53.9% of events were associated with worsening in LCI or FEV₁. Neither LCI nor FEV₁ recovered to baseline values at the next follow-up visit.Conclusions: In school-age children with CF, the LCI is a sensitive measure to assess lung function worsening with acute respiratory events and incomplete recovery at follow-up. In combination, the LCI and FEV₁ capture a higher proportion of events with functional impairment.

The dependence of the shapes of fluorescence induction curves in chloroplasts on the duration of illumination pulses

The shapes of fluorescence induction curves in spinach chloroplasts, measured using double-flash pump-probe techniques, are shown to depend on the duration of the actinic flashes. For flash durations tau(0) </= 2 mus, the variable fluorescence F(nu) grows exponentially (or nearly so) with increasing fluence J of the actinic pulses and the fluorescence induction ratio R = F(max)/F(0) is </=2.6. When tau(o) >/= 50 mus, the shapes of the F(nu) vs. J curves are sigmoidal, and R > 3.2. Overall, the experimentally observed trends suggest that, as the duration tau(0) of the actinic pulses is increased, the degree of sigmoidicity, the deduced values of the interunit excitation transfer parameter p, and the fluorescence induction ratios R, also tend to increase. These results can be accounted for in terms of a simple double-photon hit model in which a dark lag time tau(1) = 0.4-10 mus between the two hits is necessary for the observance of sigmoidal fluorescence induction curves and relatively high R ratios. It is shown that, in principle, such a model can account for the exponential and sigmoidal shapes of the fluorescence induction curves either within the context of a lake model of the photosynthetic antenna bed (free transfer of excitation between photosynthetic units) or the isolated (puddle) model of photosystem II reaction centers. However, from the known values of the R ratio measured with actinic pulses of different durations, or under continuous illumination, the lake model offers a better description of the experimental phenomena than the puddle model.

The cost of thinking about false beliefs: evidence from adults' performance on a non-inferential theory of mind task

Much of what we know about other people's beliefs comes non-inferentially from what people tell us. Developmental research suggests that 3-year-olds have difficulty processing such information: they suffer interference from their own knowledge of reality when told about someone's false belief (e.g., [Wellman, H. M., & Bartsch, K. (1988). Young children's reasoning about beliefs. Cognition, 30, 239-277.]). The current studies examined for the first time whether similar interference occurs in adult participants. In two experiments participants read sentences describing the real colour of an object and a man's false belief about the colour of the object, then judged the accuracy of a picture probe depicting either reality or the man's belief. Processing costs for picture probes depicting reality were consistently greater in this false belief condition than in a matched control condition in which the sentences described the real colour of one object and a man's unrelated belief about the colour of another object. A similar pattern was observed for picture probes depicting the man's belief in most cases. Processing costs were not sensitive to the time available for encoding the information presented in the sentences: costs were observed when participants read the sentences at their own pace (Experiment 1) or at a faster or a slower pace (Experiment 2). This suggests that adults' difficulty was not with encoding information about reality and a conflicting false belief, but with holding this information in mind and using it to inform a subsequent judgement.

An exploratory comparison of genetic counselling protocols for HNPCC predictive testing

Most UK genetics centres offering predictive testing for hereditary non-polyposis colorectal cancer (HNPCC) use an extended counselling protocol originally developed for Huntington's disease. Shortened counselling may be more appropriate in the context of treatable genetic conditions such as HNPCC. Twenty-six high-risk individuals were randomized to extended genetic counselling (two sessions of education and reflection held 1 month apart) or shortened genetic counselling (a single educational session) prior to HNPCC testing. Prospective questionnaires, interviews and transcripts of counselling sessions were analysed. Participants were unsure what to expect prior to genetic counselling and had already decided to undergo genetic testing. There was no evidence of psychological harm caused by shortened genetic counselling, with a high level of satisfaction with the counselling received in both groups. Reflective counselling occurred in both groups but was framed in terms of practical action and information. Participants expressed differing preferences for the level of information received. This exploratory study indicates that shortened genetic counselling may be an appropriate means of supporting decisions already made by individuals about HNPCC testing. However, participants would benefit from preparatory information to help them reflect on issues not previously considered, which can then be explored more fully as part of a tailored counselling approach.

A layered model of a virtual human intestine for surgery simulation

In this paper, we propose a new approach to simulate the small intestine in a context of laparoscopic surgery. The ultimate aim of this work is to simulate the training of a basic surgical gesture in real-time: moving aside the intestine to reach hidden areas of the abdomen. The main problem posed by this kind of simulation is animating the intestine. The problem comes from the nature of the intestine: a very long tube which is not isotropically elastic, and is contained in a volume that is small when compared to the intestine's length. It coils extensively and collides with itself in many places. To do this, we use a layered model to animate the intestine. The intestine's axis is animated as a linear mechanical component. A specific sphere-based model handles contacts and self-collisions. A skinning model is used to create the intestine's volume around the axis. This paper discusses and compares three different representations for skinning the intestine: a parametric surface model and two implicit surface models. The first implicit surface model uses point skeletons while the second uses local convolution surfaces. Using these models, we obtained good-looking results in real-time. Some videos of this work can be found in the online version at doi: 10.1016/j.media.2004.11.006 and at www-imagis.imag.fr/Publications/2004/FLAMCFC04.

A randomized, controlled study of insulin pump therapy in diabetic preschoolers

OBJECTIVE

To compare glycemic control, safety, and parental satisfaction in preschool-aged diabetic children randomized to treatment either with continuous subcutaneous insulin infusion (CSII) or intensive insulin injection therapy.

STUDY DESIGN

This clinical trial enrolled 42 patients <5 years of age who had been diagnosed with diabetes for at least 12 months. Children were randomly assigned to CSII (n = 21) or intensive insulin injection therapy (n = 21). Hemoglobin A1c (HbA1c) level was measured at baseline, 3, and 6 months. Secondary outcomes included severe hypoglycemic events, meter-detected hypoglycemia, blood sugar variability, body mass index (BMI), and satisfaction with therapy.

RESULTS

Thirty-seven patients completed 6 months of therapy. There was a significant decrease in HbA1c during the study period for both groups (from 8.9% +/- 0.6% to 8.6% +/- 0.6% at 3- and 6-month visits). At 3 months, children using pumps had a significantly lower HbA1c than the injection group (8.4% vs 8.8%); however, by 6 months the two groups were similar (8.5% vs 8.7%). No differences in pre-meal blood sugar variabilities were seen between groups. Children on pumps had increases in the number of meter-detected episodes of hypoglycemia. Pump therapy was safe and well tolerated. No episodes of ketoacidosis occurred in either group, whereas one hypoglycemic seizure occurred in each group. Parents reported satisfaction with CSII, with 95% of families continuing on CSII beyond the 6-month study period.

CONCLUSION

Pump therapy in preschool-aged children was not associated with clinically significant differences in glycemic control as compared with intensive injection therapy. The rationale for initiating CSII in this age group should be based on patient selection and lifestyle preference.

Delivering information about cancer genetics via letter to patients at low and moderate risk of familial cancer: a pilot study in Wales

Increasing demands upon specialist cancer genetics services have resulted in a need to explore alternative means of delivering genetic risk information to individuals at low-risk of familial cancer. This pilot study investigates patient satisfaction with a letter to low and moderate risk individuals notifying them of their risk. Sixty-six people completed a questionnaire designed to measure satisfaction with the way they had been notified of their cancer risk. Two key findings emerge from the data: first of all, whilst many respondents indicated overall satisfaction with the risk letter, a substantial number wanted more information about their risk; and secondly, low-risk individuals in this study are less reassured by and less satisfied with the risk letter than those at moderate risk. The optimal service provision for delivery of genetic risk information is likely to be one which can best respond to individual differences in information-seeking, distress and risk comprehension. There is a need therefore, for a randomised control trial to compare the effectiveness of a risk notification letter with more traditional telephone risk counselling and the implications of each mode of delivery upon the resources of specialist cancer genetics services.

Effect of errors in the identification of anatomical landmarks on the accuracy of Q angle values

OBJECTIVE

To determine the effect of error in the location of the anterior superior iliac spine, and the centres of the patella and tibial tuberosity, on the measured value of the quadriceps angle.

BACKGROUND

The quadriceps angle is said to be relevant in the etiology and management of patello-femoral pain. However, the issues around measurement accuracy have not been reported.

METHODS

Errors between 1 and 5 mm were introduced to the medial/lateral and vertical co-ordinate data describing the position of the anterior superior iliac spine, the centre of the patella and the centre of the tibial tuberosity, and the effect on the quadriceps angle determined.

RESULTS

Errors between 1 and 5 mm in the medial/lateral location of the centre of the patella produced changes in the quadriceps angle between 1.13 degrees and 5.53 degrees. Errors between 1 and 5 mm in the medial/lateral location of the tibial tuberosity produced changes in the quadriceps angle between 1.02 degrees and 5.18 degrees.

CONCLUSIONS

The quadriceps angle is highly sensitive to error in the definition of the centre of the patella and tibial tuberosity. As an approximation, these centres need to be defined with an accuracy of less than 2 mm if the error in the quadriceps angle is to remain below 5 degrees.

RELEVANCE

Until a clinical technique for measuring the quadriceps angle with a high level of accuracy is developed, the clinical use of the quadriceps angle is questionable.

Male cancer: a qualitative study of male breast cancer

Breast cancer is a rare condition in males. There is a dearth of information about the psychological and social impact of this condition. Data from six in-depth interviews with men who had breast cancer identified seven major issues. These were associated with delay in diagnosis, shock, stigma, body image, causal factors, the provision of information and emotional support. The findings from this small study suggest that there are psychological and social factors for men diagnosed with breast cancer which have implications for their care and management. The recommendations arising from this study are the development of a structured education programme aimed at all primary health-care professionals; with availability of pre and postoperative gender-specific information to alleviate the potential psychological problems associated with the diagnosis; and provision of appropriate support/counselling services for partners of patients.

A model protocol evaluating the introduction of genetic assessment for women with a family history of breast cancer

Randomised controlled trials allow comparisons to be made between different models of service delivery, but have not been used in the field of clinical genetics. With the advent of clinical governance, the evidence provided by such trials will be increasingly important in informing and shaping clinical genetics practice. The TRACE project (Trial of genetic assessment in breast cancer) is a randomised controlled trial of genetic assessment for women who are at increased risk of breast cancer because of their family history. The absence of cancer genetics service provision in Wales before this study gave a window of opportunity in which this important trial could be conducted. The present paper describes how TRACE will provide crucial evidence regarding the psychosocial as well as resource implications of adding individualised genetic assessment, genetic counselling, and (where appropriate) gene testing to typical advice and surveillance from a hospital breast clinic. In addition, it is anticipated that TRACE will represent a model for future trials of service delivery in the increasing number of complex genetic disorders where evidence on the economic implications of screening and management is currently limited.

Network morphology of straight and polymer modified asphalt cements

Asphalt cements are often regarded as a colloidal system containing several hydrocarbon constituents: asphaltenes, resins, and oils. The high molecular weight asphaltene particles are considered to be covered in a sheath of resins and dispersed in the lower molecular weight oily medium [Whiteoak (1990) The Shell Bitumen Handbook (Shell Bitumen UK, Riversdell House, Surrey, UK)]. However, the exact arrangement of the asphaltene particles within the oily phase will vary depending on the relative amounts of resin, asphaltene, and oils. It is this arrangement and the degree of association between asphaltene particles that govern the rheological properties of the cement [Simpson et al. (1961) J. Chem. Eng. Data 6:426-429; Whiteoak (1990)]. Here we report for the first time the observation of a three-dimensional network of asphaltene strands within straight, polymer-modified, and aged asphalt cements. While the existence of a asphaltene/resin micelle network has been proposed in previous studies [Whiteoak (1990)], direct observation has not been reported. The network is expected to greatly influence the rheological properties of the asphalt binder and ultimately the properties of asphalt concretes. In situ fracture studies of asphalt cement/aggregate composites indicate a possible correlation between the network structure and adhesion between the cement binder and aggregate.

Effects of hearing impairment on the patient's family and friends

A modified version of the Problems Questionnaire was administered to significant others, (SOs) usually spouses, of patients attending audiological rehabilitation clinics. The SOs were asked to list the problems they experienced because of the patient's hearing loss. They were also asked to list the problems the patient was experiencing. In addition the patients were asked to list the problems they experienced and those encountered by their SOs. SO problems concentrated more on difficulties with live speech and psychosocial problems compared with those listed by patients. They also featured more responses indicating dependence. The latter were found particularly among the SOs of male patients whose SOs also emphasised the need to repeat phrases. The SOs of female patients emphasised psychosocial problems.

Application of the Audioscan in the detection of carriers of genetic hearing loss

The authors describe the establishment of normative stimulus parameters for the Audioscan, an automated sweep frequency audiometer, for its application in the detection of audiometric notches in carriers of recessive genetic hearing loss. A sweep rate of 30 s/octave over the frequency range 300 to 4000 Hz pulsing at 2.5 pulses/s at -5 dB with a step size of 5 dB were ultimately adopted. The criterion for notches was 15 dB or greater within the frequency range 500-3000 Hz. Adopting this criterion, 14.2% of control subjects had notches. Among parents of children with non-syndromal recessive hearing loss 55% were found to have notches. Notches were found more frequently among mothers and sisters than among fathers and brothers of the patients.

Multiple sigma binding sites in guinea-pig and rat brain membranes: G-protein interactions

1. Evidence is accumulating for multiple sigma (sigma) sites in the mammalian CNS. 2. We have addressed this problem and have examined sigma site - G-protein coupling in guinea-pig and rat brain membranes. 3. Ditolylorthoguanidine (DTG), (+)-3-(3-hydroxyphenyl)-N-1-(propyl)piperidine (3PPP) and dextromethorphan displaced [3H]-DTG (3.4 nM) with low Hill slopes of 0.5, 0.6 and 0.6, respectively in guinea-pig brain membranes. 4. In the presence of 5'-guanylylimidodiphosphate (Gpp(NH)p; 100 microM), the specific binding of [3H]-DTG was reduced by 36.7%, the Hill slope of 3PPP was increased to near unity, the ability of dextromethorphan to displace DTG was virtually abolished and the Hill slope for DTG remained low (0.7), indicating the presence of at least two binding sites. These data indicate that although Gpp(NH)p removes a dextromethorphan high affinity site, two DTG selective sites remain in the presence of Gpp(NH)p. 5. The present study suggests that DTG binds to at least three sites in guinea-pig brain membranes, at least one of which is G-protein linked. 6. In rat brain membranes, DTG displaced itself (3.4 nM) with a Hill slope near 1. 3PPP displacement of [3H]-DTG was comparable with the guinea-pig (Hill slope 0.5) and displaced from more than 1 site. Dextromethorphan did not displace [3H]-DTG at concentrations below 10 microM. 7. The heterogeneity of sigma sites appears to be less in rat than in guinea-pig brain membranes.

The lack of utility of the rat vas deferens as a functional bioassay for sigma ligands

The present study examined the utility of the rat vas deferens preparation as a bioassay for sigma site ligands. sigma Ligands such as (+/-)-pentazocine, phencyclidine (PCP) and (+)-SK&F 10047 potentiated neurogenic twitch contractions. However, neither the order of potency nor the absolute potency of (+/-)-pentazocine and (+)-SK&F 10047 correlated with their affinity at central sigma sites. Furthermore, another potent sigma ligand, ditolyl-ortho guanidine (DTG) neither affected neurogenic twitch contractions nor inhibited twitch potentiation by PCP or (+)-SK&F 10047 at concentrations up to 30 mumol/l. These data indicate that the rat vas deferens is not a useful bioassay for the evaluation of sigma ligands. PCP, (+)-SK&F 10047 and (+/-)-pentazocine probably enhance neurogenic contractions in rat vas deferens primarily by inhibition of the neuronal uptake of noradrenaline.

Cost and quality implications of changes in tonometry use by optometrists

Tonometry, as a test for glaucoma, traditionally was performed routinely only on patients over age 40. In 1974 in the Helling v. Carey case the Supreme Court of Washington (state) held that an ophthalmologist was negligent in failing to administer a glaucoma test to a patient under age 40, and thus failing to diagnose primary open angle glaucoma. In a study performed at the Pennsylvania College of Optometry and the Optometric Center of Maryland an increase of utilization of tonometry on patients under the age of 40 was measured. Available literature indicates that this change occurred nationwide for optometrists in private practice. This change may result in an additional cost for eye care, without a strong indication of an improvement in quality of care.