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Acoustic rhinometry: an explanation of some common artefacts associated with nasal decongestion.

The nasal cavities of 51 healthy volunteers were examined using acoustic rhinometry before and after nasal decongestant. Several specific dimensions were studied, which included the minimum cross-sectional area, and three volumes corresponding to the anterior, middle and posterior regions of the nasal airway. An average acoustic rhinometry trace was constructed for the whole group of subjects, before and after decongestion, from data extracted from the raw data files written to the computer hard disk for each subject. A 27.5% (P < 0.0001) increase in the minimum cross-sectional area was observed, with no shift in its position. The greatest increase in nasal dimensions was seen in the anterior and middle parts of the nose, however, significant changes were also seen in the posterior nasal cavity and post nasal space. There are a number of possible sources of artefact. First, confusion of the first and second minima may produce apparent movement of the minimum cross-sectional area following nasal decongestion. Second, a postulated change in the acoustic path length may lead to apparent changes in volume in certain regions of the nose. Third, a variable and uncontrollable degree of sound energy loss will occur into the opposite nasal cavity beyond the posterior border of the septum. An apparent increase in the dimensions of this region will be seen as the opposite cavity decongests. We feel that all users of the acoustic rhinometer need to be aware of these potential sources of artefact, and attention needs to be focused on an agreed definition of the components of the acoustic rhinometry trace.

Acoustics↗

Use of rubber dam and irrigant selection in UK general dental practice.

AIM: To evaluate factors which influence rubber dam use and irrigant selection in UK National Health Service (NHS) endodontics. METHODOLOGY: A postal survey was conducted amongst two age cohorts of dentists, representing all of the 1970-73 (older) and 1990-93 (younger) graduates of two northern English dental schools (n = 643). Key and supplementary questions were posed on levels of rubber dam use, irrigant selection, and factors influencing practice in NHS endodontics. After manual checking, validated (dual) entry of responses was made to a flat ASCII data file before analysis with SPSS software. The threshold for statistical significance was set at the 95% probability level. RESULTS: Eighty-five per cent of the valid sample responded to the questionnaire. Regardless of age and qualifying school, less than one-fifth of dentists always or frequently used rubber dam, whilst 60% never used it. Qualifying school had a significant influence on rubber dam use, whilst age had a variable influence. Major disincentives to the use of rubber dam included the perception that patients do not like it, that the NHS fee was inadequate to justify its use, that it took too long to apply, and that dentists had received inadequate training. Frequent users of rubber dam were significantly less likely to cite these disincentives than nonusers. Overall, local anaesthetic solution was the most common endodontic irrigant. Irrigant choice was strongly linked to rubber dam use, and to graduation cohort. Seventy-one per cent of rubber dam users irrigated with sodium hypochlorite, compared with only 38% of nonusers. This pattern was reversed for local anaesthetic irrigation. Younger graduates were significantly more likely to irrigate with local anaesthetic solution than their older counterparts, and the younger graduates of one school showed a highly significant increase in the use of chlorhexidine. CONCLUSIONS: 1) The majority of UK Health Service dentists never use rubber dam isolation in endodontic treatment. 2) Qualifying school has a significant impact on rubber dam use, and irrigant selection. 3) Use of rubber dam has a significant association with irrigant choice in endodontics.

Age Factors↗

Social functioning, psychological functioning, and quality of life in epilepsy.

PURPOSE: Part of our research intended to explain "Quality of Life" (QoL) differences between people with epilepsy. To this end, a series of already existing generic and disease-specific health status measures were used. In this study, they were considered as determinants of people's QoL, whereas QoL itself was conceived as a general "value judgment" about one's life. METHODS: From the records of four outpatient clinics, 210 persons with epilepsy were randomly selected. During their visit to the outpatient clinic, they completed a questionnaire assessing, among other things, health perceptions and social and psychological functioning. Additional information about their medical and psychosocial status was gathered from the patient files. Data were analysed by using a hierarchical regression analysis. RESULTS: In decreasing order of importance, "psychological distress," "loneliness," "adjustment and coping," and "stigma perception" appeared to contribute most significantly to the outcome QoL as judged by the patients themselves, regardless of their physical status. In the final model, none of the clinical variables (onset, seizure frequency, side effects of antiepileptic drugs) contributed significantly anymore to the patients' "quality-of-life judgement." Apparently the effect of other variables such as seizure frequency and health perceptions, medication and side effects, life fulfillment, self-esteem, and mastery is mediated by these variables. CONCLUSIONS: Because all of the variance in QoL of the patients was explained by the psychosocial variables included in this study, health professionals should be aware of the significance of the psychosocial functioning of the patients and the role it plays in the achievement of a good QoL. Both informal and professional support may be an adjunct to conventional treatment. In future research, this issue should be given high priority.

Adaptation, Psychological↗

Computer evaluation of network dynamics models with application to cell cycle control in budding yeast.

Cellular processes are governed by complex networks of interacting genes and proteins. Theoretical molecular biologists attempt to describe these processes via mathematical models by writing biochemical reaction equations. Modellers are building increasingly larger and complex mathematical models to describe these cellular processes, making model evaluation a time consuming and difficult task. The authors describe an automatable process for model evaluation and a software system that implements this process. The software is adaptable to many types of models and is freely available along with all needed data files. The cell cycle control system for budding yeast is known in fine detail and constrained by more than 100 phenotypic observations in mutant strains. As an example, the authors apply their process to a model of cell cycle control in budding yeast containing dozens of regulatory equations and explaining nearly all of the known mutant phenotypes.

Cell Cycle↗

Associated positive patch test reactions to standard contact allergens.

BACKGROUND: Patch testing with a standard allergen series often yields positive reactions to more than 1 allergen in a patient. OBJECTIVE: To identify all significantly associated pairs of positive reactions and to assess their relation to the strength of the reactions and to the irritative potential of the allergens. METHODS: Based on the filed data of 57,822 patients, associations between positive reactions to 2 different allergens were quantified with odds ratios. Statistical methods included Fisher's exact test, the Bonferroni adjustment to account for the effect of multiple testing, and the Spearman rank correlation. RESULTS: Out of the 32,779 patients with complete readings of 24 standard allergens, 7,501 had shown more than 1 positive reaction. Statistically significant associations were detected for 166 out of the 276 possible different combinations of 2 distinct positive reactions, including combinations that had not been identified before. Patients with a strong reaction or a positive reaction to an allergen with a high irritative potential tended to have additional positive reactions to further allergens more often than others, but the number of significant associations was not dependent on these parameters. CONCLUSION: There are more significant associations that have to be taken into account for patch testing than has been known so far. Although irritation can favor a higher number of positive reactions, significant associations of positive reactions to distinct allergens are probably caused by other mechanisms that require further analyses.

Adult↗

Trends in fetal growth among singleton gestations in the United States and Canada, 1985 through 1998.

We examined trends in fetal growth among singleton live births in the United States and Canada. The data files (n = 48,637,680; 16.6% blacks) for US births, and the Canadian Birth Database of Statistics Canada (n = 3,167,702) for Canadian births were used. Trends were assessed between 1985-86 and 1997-98 with reference to mean birthweight, birthweight-for-gestational-age z-score, and proportions delivered low birthweight (< 2,500 g), small for gestational age (SGA: birthweight < 10th centile for gestational age) and large for gestational age (LGA: birthweight > 90th centile). The term "mean birth weight" increased in the US and Canada between 1985 and 1998, as have the mean z-score. Rates of term SGA births declined among US (11% among whites and 12% among blacks) and Canadian births (27%). Preterm SGA births increased by 3% and 17%, respectively, among US whites and blacks, but declined by 11% among Canadian births. Further, term LGA births increased in the US (5% among whites and 9% among blacks) and Canada (24%). Preterm LGA births declined by 13%, 25%, and 14% among US whites and blacks, and Canadian births, respectively. These findings suggest that US and Canadian babies are getting bigger. The role of preterm obstetrical induction and preterm cesarean delivery are likely to have influenced these trends.

Birth Weight↗

[Rational diagnosis of pediatric pharyngeal abscess].

BACKGROUND: Diagnostic procedures intend to differentiate superficial cervical abscesses from deep abscesses and uncomplicated lymphadenitis. They should provide identification of the causing agent, of the route of infection and of possible underlying diseases. Present techniques for examining pediatric cervical abscesses should be assessed. METHODS: Currently published data on diagnostic procedures in pediatric neck abscess from National Library of Medicine data files were evaluated. Moreover, clinical findings, diagnostic procedures, therapy and outcome of 47 children with cervical abscess treated from 1992-1996 were retrospectively evaluated. RESULTS: Studies providing appropriate evidence on the value of various diagnostic procedures in pediatric cervical abscesses were not found. In 47 patients with confirmed cervical abscess treated at our department, clinical examination, erythrocyte sedimentation rate and ultrasound examination of the neck were sufficient to establish the correct diagnosis. Additional investigations such as MRI or CT-scans, chest X-rays, Mendel-Mantoux test, various virus titres and other laboratory examinations were performed only in selected cases. The route of invasion (tonsil, dental or otogeneous) could be identified in 13 children. In 4 children an infected cervical cyst was found. CONCLUSIONS: Clinical examination, erythrocyte sedimentation rate and sonography are appropriate to establish the diagnosis of pediatric cervical abscess and in accordance with the principles of Managed Care.

Child↗

[Stress analysis of an anatomically-adapted femur shaft prosthesis (Lubinus SPII)].

OBJECTIVE: Very good clinical long-term results of the Lubinus SP II hip prosthesis stem were reported in the literature. We therefore asked whether there is a relationship between these findings with biomechanical data of strain gauge measurements. METHOD: 14 strain gauges were applied at a femur being measured at 10 different load cases before and after implantation of the stem. RESULTS: After stem implantation a similar patterns of principal stress distributions was observed, however, the magnitude was markedly reduced. A striking reduction of the hoop stresses at the femoral calcar was seen in the case of a missing collar contact. Even in the case of a perfect collar contact the hoop stresses were diminished after strem implantation. The S-shaped physiological stem did not correspond with a specific stress pattern measured at the femoral surface. CONCLUSION: These results suggest that the stresses at the femoral calcar may be lower than the limits of bone growth while the other parts of the femur are more physiologically stressed. However, the prosthesis may tolerate a missing collar contact during a long follow-up period. The large experimental data file presented here could be used to validate future finite element analyses which could evaluate the stress distribution within internal parts of the bone and the cement layer.

Aged↗

Placenta previa in singleton and twin births in the United States, 1989 through 1998: a comparison of risk factor profiles and associated conditions.

OBJECTIVE: The purpose of this study was to compare risk factor profiles for placenta previa between singleton and twin live births. STUDY DESIGN: This cohort study was based on United States natality data files (1989 through 1998) and comprised 37,956,020 singleton births and 961,578 twin births. Women who were diagnosed with placenta previa were included only if they were delivered by cesarean delivery. Risk factors for placenta previa that were examined included sociodemographic (age, gravidity, education, marital status, and race), behavioral (prenatal care, smoking, and alcohol use), previous preterm birth, and medical and obstetric factors. Effect modification between maternal age and gravidity and the dose-response relationship with number of cigarettes smoked/day on placenta previa risk were also evaluated. RESULTS: The rate of placenta previa was 40% higher among twin births (3.9 per 1,000 live births, n = 3,793 births) than among singleton births (2.8 per 1,000 live births, n = 104,754 births). Comparison of risk factors for placenta previa between the singleton and twin births revealed fairly similar risk factor profiles. Compared with primigravid women <20 years old, the risk for placenta previa increased by advancing age and by increasing number of pregnancies among both singleton and twin births. The number of cigarettes smoked per day also showed a dose-response trend for placenta previa risk in the two groups. CONCLUSION: The increased rate of placenta previa among twin births underscores the need to monitor carefully such pregnancies with heightened suspicion and awareness for the development of this condition.

Adult↗

Serum antibody response to the heat shock protein 60 of Chlamydia trachomatis in women with developing cervical cancer.

OBJECTIVE: The purpose of this study was to determine whether serum antibody response to the three versions of chlamydial heat shock protein 60 is associated with an increased risk for cervical cancer. STUDY DESIGN: Women with cervical carcinoma were identified by linking the data files of three Nordic serum banks with cancer registries. Overall, 178 women with invasive cervical carcinoma were identified. For each case, the earliest prediagnostic serum sample was chosen, and three matched control subjects who were free of cancer at the time of the case diagnosis were selected randomly. Serum antibodies to the chlamydial heat shock protein 60 were measured by enzyme-linked immunosorbent assay and correlated with the risk of the subsequent development of cervical cancer. RESULTS: Antibodies to chlamydial heat shock protein 60-1 were associated with cervical squamous cell carcinoma among cases with long lag time (>3.5 years; odds ratio, 2.4; 95% CI, 1.1-5.1). Antibodies to chlamydial heat shock protein 60-2 or chlamydial heat shock protein 60-3 were not associated with cervical cancer risk. CONCLUSIONS: The finding that chlamydial heat shock protein 60-1 antibodies are associated with an increased cervical cancer risk suggests that persistent Chlamydia trachomatis infection may contribute to cervical neoplasia.

Antibodies↗

Methods for identifying proteins by using partial sequences.

Methods for the identification of a protein segment by using the information from partial sequence analyses are described. If the protein sequence is known, a segment can usually be identified with confidence through comparison with the data file of all known sequences when the identity and position of only seven amino acid residues (not necessarily contiguous) are known. Partial sequences are obtained from extremely sensitive microsequencing procedures. Tissue is incubated with amino acids, one or more of which are distinctively radiolabeled. Proteins of interest are isolated and a sequenator experiment performed to locate the positions of radioactivity in an NH(2)-terminal segment of approximately 30 residues. We derive and investigate an equation for the probability of finding a unique match to any pattern of radioactivity. From this we suggest a new strategy. In one incubation, several amino acids are labeled with each kind of isotope. The most information is contained in patterns in which approximately equal numbers of positions are occupied by residues distinguished by different labels (including no label). The amino acid composition of the segment will typically not be known in advance. Labeling residues expected to occupy 36% of the positions suffices for a 98% chance of success in uniquely characterizing any human segment. Such a strategy will permit the identification of most proteins from a single tissue incubation. The mathematical discussion is general and applies to any segment from a sequence and to sequences obtained by any method. Improved identification procedures should expedite the accumulation of information on the expression and function of proteins.

Amino Acid Sequence↗

Rice proteomics: a step toward functional analysis of the rice genome.

The technique of proteome analysis with two-dimensional PAGE has the power to monitor global changes that occur in the protein expression of tissues and organisms and/or expression that occurs under stresses. In this study, the catalogues of the rice proteome were constructed, and a functional characterization of some of these proteins was examined. Proteins extracted from tissues of rice and proteins extracted from rice under various kinds of stress were separated by two-dimensional PAGE. An image analyzer was used to reveal a total of 10,589 protein spots on 10 kinds of two-dimensional PAGE gels stained by Coomassie Brilliant Blue. The separated proteins were electroblotted onto a polyvinylidene difluoride membrane, and the N-terminal amino acid sequences of 272 of 905 proteins were determined. The internal amino acid sequences of 633 proteins were determined using a protein sequencer or mass spectrometry after enzyme digestion of the proteins. Finally, a data file of rice proteins that included information on amino acid sequences and sequence homologies was constructed. The major proteins involved in the growth and development of rice can be identified using the proteome approach. Some of these proteins, including a calcium-binding protein that turned out to be calreticulin and a gibberellin-binding protein, which is ribulose-1,5-bisphosphate carboxylase/oxygenase activase in rice, have functions in the signal transduction pathway. The information thus obtained from the rice proteome will be helpful in predicting the function of the unknown proteins and will aid in their molecular cloning.

Agrobacterium tumefaciens↗

A recipe-based, diet-planning modelling system.

In a recent article in the British Journal of Nutrition, Sklan & Dariel (1993) presented a method for diet planning employing a mixed-integer programming algorithm for meeting nutritional requirements at minimum costs for institutions or individuals. They recognized that most food items are generally consumed in whole units and as such they are represented as integer variables. However, as in most previous studies, they derived the minimum cost diets by optimizing over purchased food items. The present paper presents a computer-assisted, diet-planning modelling system for individuals by optimizing over recipes instead of food items. This is accomplished by restricting the integer programming solutions to those bundles of food that represent reasonably popular meal recipes. The modelling system is composed of three main components: recipe data entry, database management, and the model. The recipe data entry component creates and stores recipes. It also provides nutritional analysis of the recipes. The database management component creates and maintains several databases necessary to build the modelling data file. The modelling component solves the user-specified model. Currently, the model component can solve for the optimal diet by minimizing cost or minimizing cooking and preparation time. The optimal diet is prepared to satisfy the recommended nutritional guidelines for a predefined group of individuals for 1 week. The system currently has 895 popular recipes found in Hawaii. Diet plans generated using this modelling system with differing objectives are discussed and compared.

Computer Simulation↗

The Finnish Arthroplasty Register: report of the hip register.

The Finnish Arthroplasty Register was established in 1980. Between 1980 and 1999, 62,841 primary and 12,224 revision total hip arthroplasties (THA) were recorded. The annual number of both primary and revision THA has increased: in 1999, the incidence of primary THAs was 93/100,000. 174 implant designs have been used, but the 6 commonest implants comprised 82% in 1999. Since the late 1980s, more than 40% of the hips were inserted without cement. Over 47% of the cementless primary hip prostheses were used in patients younger than 60 years and over 93% of the cemented primary hips were used in patients 60 years or older. The 10-year survival rate was 72 (95% CI 67-76)% in patients younger than 55 years and 90 (89-91)% in patients older than 70 years. The commonest reasons for revision were aseptic loosening (65%), dislocation (9%) and infection (7%). In revisions, the 5-year survival of the cementless hip prosthesis improved over time: it was 85 (82-87)% in 1985-1989, 89 (88-91)% in 1990-1994 and 92 (88-95)% in 1995-1999. There are striking differences between the Arthroplasty Registers of Scandinavia as regards the end-point definition of survival. The Finnish Arthroplasty Register considers all reasons for revisions as the end-point of survival, but the Swedish register takes into account only aseptic loosening, so direct comparisons between registers are not possible. Recent data from the Finnish Arthroplasty Register indicate that the results of total hip replacements are improving in Finland. With the civic registration number, one can link and match data files. For example, with use of the Finnish Cancer Register, we found no increase in the risk of cancer after a THA.

Arthroplasty, Replacement, Hip↗

Bile acid malabsorption in patients with chronic diarrhoea: clinical value of SeHCAT test.

BACKGROUND: Bile acid malabsorption (BAM), a cause of chronic diarrhoea, can be diagnosed by the SeHCAT test. The purpose of this study was to evaluate the usefulness of SeHCAT testing by assessing the extent of BAM and describing the clinical characteristics in a group of patients with chronic diarrhoea. Clinical outcome after treatment with cholestyramine was also evaluated. METHODS: During a 5-year period (1997-2001) the SeHCAT test was performed in 135 patients in whom a primary programme for diagnostic evaluation of chronic diarrhoea had not revealed a cause. File data from 133 patients could be evaluated. RESULTS: In 44% of patients, bile acid absorption was normal with SeHCAT retention > or = 15%. Impaired SeHCAT retention was found in 56%. All patients with ileocaecal resections had retention values < 10%. Patients with microscopic colitis presented with BAM in 39%. Only one patient with idiopathic BAM presented with steatorrhoea as opposed to 11 patients with type 1 and 3 BAM. Patients with idiopathic BAM and/or SeHCAT retention values < 5% had the best response to treatment with cholestyramine. CONCLUSIONS: The SeHCAT test is of value in evaluation of patients with chronic diarrhoea as a second-line investigation with a high diagnostic yield. The only a priori parameter to predict BAM was the existence of ileocaecal resections. The result of the SeHCAT test seems to predict the benefit of treatment with cholestyramine.

Adult↗

Prostate cancer--prevalence-based healthcare costs.

OBJECTIVE: To calculate the total costs of in- and outpatient healthcare for patients with prostate cancer based on an episode-of-care approach. The cost analysis includes costs incurred during the first year of diagnosis, a longitudinal 3-year analysis and the incremental cost of prostate cancer during the first year of diagnosis. MATERIAL AND METHODS: Patients registered with prostate cancer between 1998 and 2000, according to the data files of the Southern Swedish Regional Tumour Registry, were given encrypted identifiers that could also be used in the Patient Administrative System of the Region Skåne County Council, making it possible to identify consumption of healthcare on an episode-of-care basis. Itemized costs for resources used by each individual patient were calculated from the complete accounting system of the County Council. RESULTS: Healthcare costs for prostate cancer during the first year varied between 45 000 and 51 000 SEK per patient. The second- and third-year costs were progressively lower, with an estimated total cost of 114 000 SEK over a period of 3 years. The age-standardized incremental cost of prostate cancer corresponded to 33 000 SEK during the first year, compared to the average cost per inhabitant. CONCLUSIONS: The episode-of-care approach, based on encrypted identifiers for the identification of the diagnoses of individual patients and their utilization of healthcare, gives a unique opportunity to estimate the healthcare costs of specific diseases. The incremental healthcare cost per patient with prostate cancer corresponded to 33 000 SEK during the first year.

Aged↗

Preoperative spinal hydrodynamics versus clinical change 1 year after shunt treatment in idiopathic normal pressure hydrocephalus patients.

Nineteen consecutive cases treated for idiopathic normal pressure hydrocephalus (iNPH) with ventriculo-peritoneal shunts were clinically followed prospectively. Change in clinical state one year after shunt surgery was assessed as change on a 15-3 score NPH Grade Scale. Preoperative spinal hydrodynamics were assessed using a constant-rate lumbar infusion test. The pressure recordings were stored as raw data files and analysed retrospectively with regard to the mean cerebrospinal fluid pressure (CSFP), as well as mean CSFP wave amplitudes. Changes in NPH score 1 year after shunt surgery correlated significantly with the levels of single CSFP wave amplitudes, but not with the lumbar resistance to CSF outflow (R(out)). Mean CSFP wave amplitude was thus, in this cohort, a better predictor of clinical change one year after shunt treatment than R(out).

Aged↗