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PubMed1984

Computer assistance in the control of depth of anaesthesia.

A control system was used to bring the tension of anaesthetic in the brain to any value specified (in MAC units) by the anaesthetist and then maintain it constant until a new value was specified. The control was applied to a volatile agent but allowance was automatically made for the anaesthetic effect of any nitrous oxide concomitantly administered by the anaesthetist. The inspired concentration required to achieve the desired brain tension was calculated from a model of the patient and set automatically on the vaporizer. The quantification of the model was matched to the patient on the basis mainly of body mass and periodic non-invasive measurements of alveolar ventilation and cardiac output. In order to adapt the model to the patient an arterial blood sample was taken every 30 min to obtain the arterial tension of halothane for use as feedback. The system has been tested on eight Alsatian dogs. After omitting results affected by avoidable errors, the SD of the measured-to-computed arterial tension ratio was less than 10%.

Anesthesia, Inhalation↗
PubMed2006

Household food insecurity and food expenditure in Bolivia, Burkina Faso, And the Philippines.

This study examined the association between food insecurity, determined by a modified version of the U.S. Household Food Security Survey Module (US HFSSM), and total daily per capita (DPC) consumption (measured as household expenditures) in Bolivia, Burkina Faso, and the Philippines. Household food insecurity was determined by an adapted 9-item US HFSSM version. A short version of the World Bank's Living Standards Measurement Study (LSMS) consumption module measured household expenditures. Focus groups were used to adapt the survey instrument to each local context. The sample (n approximately 330 per country) includes residents of urban and rural areas. A 12-month food expenditure aggregate was generated as part of the total household expenditures calculation. DPC food expenditure, which represented over 60% of the total household consumption, as well as expenditures on specific food groups correlated with food insecurity both as a continuous Food Insecurity Score (FinSS) and a tricategorical food insecurity status variable. ANOVA and regression analysis were executed adjusting for social and demographic covariates. Food-secure households have significantly higher (P < 0.05) total DPC food expenditures as well as expenditures on animal source foods, vegetables, and fats and oils than moderately and severely food-insecure households. The results offer evidence that the US HFSSM is able to discriminate between households at different levels of food insecurity status in diverse developing world settings.

Adult↗
PubMed2004

A novel technique based on a PNA hybridization probe and FRET principle for quantification of mutant genotype in fibrous dysplasia/McCune-Albright syndrome.

Somatic mutations are present in various proportions in numerous developmental pathologies. Somatic activating missense mutations of the GNAS gene encoding the Gs(alpha) protein have previously been shown to be the cause of fibrous dysplasia of bone (FD)/McCune-Albright syndrome (MAS). Because in MAS patients, tissues as diverse as melanocytes, gonads and bone are affected, it is generally accepted that the GNAS mutation in this disease must have occurred early in development. Interestingly, it has been shown that the development of an active FD lesion may require both normal and mutant cells. Studies of the somatic mosaic states of FD/MAS and many other somatic diseases need an accurate method to determine the ratio of mutant to normal cells in a given tissue. A new method for quantification of the mutant:normal ratio of cells using a PNA hybridization probe-based FRET technique was developed. This novel technique, with a linear sensitivity of 2.5% mutant alleles, was used to detect the percentage mutant cells in a number of tissue and cell culture samples derived from FD/MAS lesions and could easily be adapted for the quantification of mutations in a large spectrum of diseases including cancer.

Alleles↗
PubMed2006

Neuropsychological functioning in adolescents and young adults at genetic risk for schizophrenia and affective psychoses: results from the Harvard and Hillside Adolescent High Risk Studies.

Siblings and offspring of persons with schizophrenia carry elevated genetic risk for the illness and manifest attentional and memory impairments. Because less is known about other neuropsychological functions and their specificity in adolescents, we conducted a genetic high-risk (HR) study of schizophrenia (HR-SCZ) and affective psychosis (HR-AFF). Participants (ages 12-25) were from the Harvard Adolescent High-Risk and Hillside Family studies, including 73 HR-SCZ, 18 HR-AFF, and 84 community controls (CCs) recruited in metropolitan Boston and New York. Groups were compared on overall neurocognitive functioning, 6 domains, and 13 test scores, controlling for age, parental education, and correlated data within families. The HR-SCZ group was significantly impaired overall, while the HR-AFF group demonstrated a trend toward overall impairment. HR-SCZ subjects showed significantly lower Verbal Ability (d = .73) and Executive Functioning/Working Memory (d = .47) than CCs. HR-AFF subjects showed reduced Verbal Ability (d = .64) compared to CCs. Excluding 12 CCs with a parental history of depression (without psychosis) led to larger differences between HR and CC groups across domains. Moreover, HR-SCZ and CC group differences in Verbal Memory (d = .39) and Visual-Spatial (d = .34) became statistically significant. There were no significant differences between HR-SCZ and HR-AFF groups. Data support a modest neuropsychological deficit in persons at genetic HR for psychosis, with a broader range of deficits in HR-SCZ. Future work should assess the relationship of neurocognition to adaptive functioning and possible onset of psychosis in HR samples. Ascertainment criteria for controls may markedly influence results and interpretation of group differences.

Adolescent↗
PubMed1993

Quantifying social development in autism.

OBJECTIVE: This study was concerned with the development of quantitative measures of social development in autism. METHOD: Multiple regression equations predicting social, communicative, and daily living skills on the Vineland Adaptive Behavior Scales were derived from a large, normative sample and applied to groups of autistic and nonautistic, developmentally disordered children. Predictive models included either mental or chronological age and other relevant variables. RESULTS: Social skills in the autistic group were more than two standard deviations below those predicted by their mental age; an index derived from the ratio of actual to predicted social skills correctly classified 94% of the autistic and 92% of the nonautistic, developmentally disordered cases. CONCLUSIONS: The findings are consistent with the idea that social disturbance is central in the definition of autism. The approach used in this study has potential advantages for providing more precise measures of social development in autism.

Adolescent↗
PubMed1997

Psychosocial functioning of homeless children.

OBJECTIVE: To investigate the psychosocial characteristics of homeless children and their parents. METHOD: Homeless families were assessed within 2 weeks of admission to seven hostels and were compared with a group of housed families matched for socioeconomic status. Measures included a semistructured interview, the General Health Questionnaire (GHQ), the interview Schedule for Social Interaction, the Child Behavior Checklist (CBCL), the Communication domain of the Vineland Adaptive Behavior Scales, and height and weight percentiles. The sample consisted of 113 homeless families (249 children aged 2 through 16 years) and 29 comparison families (83 children). RESULTS: Homeless families primarily consisted of single mothers and an average of two children, who had become homeless because of domestic violence (56%) or violence from neighbors (29%). Homeless mothers reported high rates of previous abuse (45%) and current psychiatric morbidity (49% caseness on the GHQ) and poor social support networks compared with housed controls. Homeless children were more likely to have histories of abuse, living in care, and being on the at-risk child protection register and less likely to have attended school or a preschool/day-care center since admission to the hostel. They also had delayed communication and higher CBCL scores. Maternal GHQ scores best predicted CBCL caseness. CONCLUSIONS: Homeless mothers and children have high rates of psychosocial morbidity, which are related to multiple risk factors and chronic adversities. Their complex needs should be best met by specialized and coordinated health, social, and educational services.

Adolescent↗
PubMed1994

Adaptive digital notch filter design on the unit circle for the removal of powerline noise from biomedical signals.

This paper investigates adaptive digital notch filters for the elimination of powerline noise from biomedical signals. Since the distribution of the frequency variation of the powerline noise may or may not be centered at 60 Hz, three different adaptive digital notch filters are considered. For the first case, an adaptive FIR second-order digital notch filter is designed to track the center frequency variation. For the second case, the zeroes of an adaptive IIR second-order digital notch filter are fixed on the unit circle and the poles are adapted to find an optimum bandwidth to eliminate the noise to a pre-defined attenuation level. In the third case, both the poles and zeroes of the adaptive IIR second-order filter are adapted to track the center frequency variation within an optimum bandwidth. The adaptive process is considerably simplified by designing the notch filters by pole-zero placement on the unit circle using some suggested rules. A constrained least mean-squared (CLMS) algorithm is used for the adaptive process. To evaluate their performance, the three adaptive notch filters are applied to a powerline noise sample and to a noisy EEG as an illustration of a biomedical signal.

Algorithms↗
PubMed2006

Implementing online natural gradient learning: problems and solutions.

The online natural gradient learning is an efficient algorithm to resolve the slow learning speed and poor performance of the standard gradient descent method. However, there are several problems to implement this algorithm. In this paper, we proposed a new algorithm to solve these problems and then compared the new algorithm with other known algorithms for online learning, including Almeida-Langlois-Amaral-Plakhov algorithm (ALAP), Vario-eta, local adaptive learning rate and learning with momentum etc., using sample data sets from Proben1 and normalized handwritten digits, automatically scanned from envelopes by the U.S. Postal Services. The strong and weak points of these algorithms were analyzed and tested empirically. We found out that using the online training error as the criterion to determine whether the learning rate should be changed or not is not appropriate and our new algorithm has better performance than other existing online algorithms.

Algorithms↗
PubMed1995

Personality disorders and psychosocial changes after intensive psychotherapy: a prospective follow-up study of an outpatient psychotherapy project, 5 years after end of treatment.

This report presents the results of a 7-year prospective outcome study designed to examine the psychosocial changes during and after therapy among 25 outpatients suffering from personality disorders and psychoses. The therapeutic approach was based mainly on object relations theory and psychodynamic self-psychology, and focused in particular on affect consciousness, parental images, self-image and interpersonal relations. Twenty patients completed the form which measured psychosocial changes during therapy, and 21 persons participated at follow-up. The data show statistically significant changes in the capacity to tolerate intimate relationships and actually establish such relationships, improved quality of contact in relationships with friends, a general raising of socioeconomic status and reduced use of ordinary health and social services. Both the global psychosocial outcome at follow-up as measured by HSRS and the general level of symptoms measured by SCL-90 suggest that 76% of the sample had reached a level of psychosocial functioning and adaptation that can be defined as "no-caseness".

Adult↗
PubMed1994

Digital signal processing chip implementation for detection and analysis of intracardiac electrograms.

The adoption of digital signal processing (DSP) microchips for detection and analysis of electrocardiographic signals offers a means for increased computational speed and the opportunity for design of customized architecture to address real-time requirements. A system using the Motorola 56001 DSP chip has been designed to realize cycle-by-cycle detection (triggering) and waveform analysis using a time-domain template matching technique, correlation waveform analysis (CWA). The system digitally samples an electrocardiographic signal at 1000 Hz, incorporates an adaptive trigger for detection of cardiac events, and classifies each waveform as normal or abnormal. Ten paired sets of single-chamber bipolar intracardiac electrograms (1-500 Hz) were processed with each pair containing a sinus rhythm (SR) passage and a corresponding arrhythmia segment from the same patient. Four of ten paired sets contained intraatrial electrograms that exhibited retrograde atrial conduction during ventricular pacing; the remaining six paired sets of intraventricular electrograms consisted of either ventricular tachycardia (4) or paced ventricular rhythm (2). Of 2,978 depolarizations in the test set, the adaptive trigger failed to detect 6 (99.8% detection sensitivity) and had 11 false triggers (99.6% specificity). Using patient dependent thresholds for CWA to classify waveforms, the program correctly identified 1,175 of 1,197 (98.2% specificity) sinus rhythm depolarizations and 1,771 of 1,781 (99.4% sensitivity) abnormal depolarizations. From the results, the algorithm appears to hold potential for applications such as real-time monitoring of electrophysiology studies or detection and classification of tachycardias in implantable antitachycardia devices.

Algorithms↗
PubMed1984

Psychological adjustment to coronary artery surgery.

In a study of psychological adjustment to coronary artery bypass surgery 23 patients who underwent surgery were seen pre-operatively, prior to discharge and one year after surgery. A comparison sample of 19 patients not tested pre-surgically was contacted by postal questionnaire one year post-operatively. An hierarchical grouping analysis carried out on seven outcome variables yielded a two-group solution for the study sample and this was replicated in the comparison sample. Group 1 indicated change for the better and Group 2 change for the worse since surgery. Discriminant function analysis of 23 pre-operative and operative variables for the first sample indicated ability to cope with stressful events and neuroticism were significant predictors of outcome. Patients in the comparison sample did not differ from the study sample in outcome measures, indicating no effect of assessment prior to operation for the study sample.

Adaptation, Psychological↗
PubMed1979

The responses of afferent fibres from the glabrous skin of the hand during voluntary finger movements in man.

1. Afferent activity of 111 single units from the glabrous skin area was recorded percutaneously in the median nerve of human subjects, using tungsten electrodes. 2. The majority of the units (103) were classified as low-threshold mechano-sensitive units belonging to one of the four categories previously described: rapidly adapting with small receptive fields (RA), rapidly adapting with large receptive fields (PC, presumed Pacinian corpuscle units), slowly adapting with small fields (SA I), and slowly adapting with large fields (SA II). The size of the responses (in number of impulses) to indentation and stretching of the skin was compared with that of the responses elicited during voluntary isotonic finger movements, which avoided trivial excitation of the units by direct touch. 3. All four types of units, and 77% of the single units, were activated by isotonic movements. The decreasing order of responsiveness was PC, SA II, SA I, RA. 4. Almost all responsive units were excited during the dynamic phase of ramp and smooth oscillatory movements. Static responses, on the other hand, occurred only with 50% of the slowly adapting units, corresponding to a third of the total sample (SA II, 81%; SA I, 17%. 5. For all four types of units the dynamic responses to movements were of similar size as the responses to localized skin indentation with a von Frey hair at five times threshold. 6. The results are discussed with regard to the possible implications for kinaesthesia and motor control.

Adult↗
PubMed1980

Innervation density of mechanoreceptive fibres supplying glabrous skin of the monkey's index finger.

1. The innervation densities of mechanoreceptive fibres supplying the ridged glabrous skin of the middle and terminal phalanges of the monkey's (Macaca nemestrina) index finger were estimated using a combination of histological and neurophysiological procedures. 2. This estimate was based on (a) a count of the total number of A beta myelinated fibres in the palmar digital nerve at the level of the proximal phalanx, (b) the demonstration that the majority of A beta fibres in the monkey's palmar digital nerve are mechanoreceptive afferents, (c) the estimation, based on a sample of 398 fibres, of the fractions of rapidly adapting, slowly adapting and Pacinian mechanoreceptive fibres in the palmar digital nerve, and (d) the estimation of the area of glabrous skin innervated by the palmar digital nerve. 3. The estimated innervation density of the finger pad and the skin of the middle phalanx were: rapidly adapting fibres, 178 and 80/cm2; slowly adapting fibres, 134 and 46/cm2; and Pacinian fibres, 13/cm2 for both phalanges.

Animals↗
PubMed2006

Introducing TreeClimber, a test to compare microbial community structures.

The phylogenetic and ecological complexity of microbial communities necessitates the development of new methods to determine whether two or more communities have the same structure even though it is not possible to sample the communities exhaustively. To address this need, we adapted a method used in population genetics, the parsimony test, to determine the relatedness of communities. Here we describe our implementation of the parsimony test, TreeClimber, in which we reanalyzed six previously published studies and compared the results of the analysis to those obtained using integral-LIBSHUFF.

Algorithms↗
PubMed2006

Recombinant multiepitope protein for early detection of dengue infections.

Dengue fever is a mosquito-borne viral disease prevalent mainly in tropical countries. As the clinical manifestations of dengue are not very unique, laboratory diagnosis is crucial in identifying cases of dengue infection. Detection of dengue infection based on the identification of antidengue antibodies has emerged as a practical and reliable means of diagnosing dengue fever. We recently developed a customized recombinant dengue multiepitope protein (r-DME-G) that can specifically detect the immunoglobulin G (IgG) class of antidengue antibodies in patient sera. Using this strategy, we have now created another dengue multiepitope protein, r-DME-M, with specificity for the IgM class of antidengue antibodies. A synthetic gene encoding the r-DME-M protein was expressed as a maltose-binding protein fusion in Escherichia coli. The recombinant protein was purified in a single affinity chromatographic step to obtain yields of approximately 15 mg purified protein/liter of culture. The purified protein was used to develop an in-house IgM enzyme-linked immunosorbent assay (ELISA) and tested using a panel of 172 patient sera characterized using the commercially available Dengue Duo rapid strip test from PanBio, Australia. The IgM ELISA results showed that the r-DME-M protein not only recognized all IgM(+) samples identified by the PanBio test but also identified samples missed by the latter test. We also successfully adapted the r-DME-M protein to a rapid strip test format. This approach of creating customized antigens coupled to overexpression in E. coli and simple purification offers a promising alternative option to dengue diagnosis with the potential to circumvent the drawbacks of the whole virus antigen-based commercial kits.

Amino Acid Sequence↗
PubMed1987

Detection and quantitation of toxic shock syndrome toxin 1 in vitro and in vivo by noncompetitive enzyme-linked immunosorbent assay.

Toxic shock syndrome toxin 1 (TSST-1), an exotoxin produced by many Staphylococcus aureus strains, is implicated as the prime causal agent of toxic shock syndrome (TSS). A sensitive and specific noncompetitive enzyme-linked immunosorbent assay (ELISA) capable of detecting TSST-1 at concentrations from 0.5 to 16 ng/ml was developed. This assay did not detect other staphylococcal enterotoxins including A, B, C1, C2, C3, D, and E. Possible interactions with protein A were readily eliminated by pretreatment of test samples with 10% normal rabbit serum. The assay was adapted for rapid screening of TSST-1 production by S. aureus isolates in culture supernatants in vitro and for detection of TSST-1 in vaginal washings of TSS patients and healthy controls in vivo. All 35 S. aureus isolates confirmed to be TSST positive by Ouchterlony immunodiffusion and 59 of 60 isolates confirmed to be TSST-1 negative gave concordant results by ELISA. Interestingly, toxigenic S. aureus strains isolated from TSS patients quantitatively produced significantly more TSST-1 in vitro compared with toxigenic control strains (P less than 0.05, Mann-Whitney rank sum test). TSST-1 could be detected by ELISA in three of four vaginal washings collected within 3 days of hospitalization from three women with acute menstrual TSS, compared with 0 of 17 washings from nine TSS patients hospitalized longer than 3 days (P = 0.003, Fisher's exact test) and 1 of 15 washings from 14 healthy control women (P = 0.016). This noncompetitive ELISA should be particularly useful for rapid screening of TSST-1 production by S. aureus isolates, for the purification and biochemical characterization of TSST-1, and for human and animal studies of the pathogenesis of TSS.

Bacterial Toxins↗
PubMed2003

Molecular epidemiology of Pseudomonas aeruginosa colonization in a burn unit: persistence of a multidrug-resistant clone and a silver sulfadiazine-resistant clone.

To study the epidemiology of Pseudomonas aeruginosa colonization in a 32-bed burn wound center (BWC), 321 clinical and 45 environmental P. aeruginosa isolates were collected by prospective surveillance culture over a 1-year period and analyzed by serotyping, drug susceptibility testing, and amplified fragment length polymorphism (AFLP) analysis. Among 441 patients treated at the center, 70 (16%) were colonized with P. aeruginosa, including 12 (17%) patients who were colonized on admission and 58 (83%) patients who acquired the organism during their stay. Of the 48 distinct AFLP genotypes found, 21 were found exclusively in the environment, 15 were isolated from individual patients only, and 12 were responsible for the colonization of 57 patients, of which 2 were also isolated from the environment, but secondary to patient carriage. Polyclonal P. aeruginosa colonization with strains of two to four genotypes, often with different antibiotic susceptibility patterns, was observed in 19 patients (27%). Two predominant genotypes were responsible for recurrent outbreaks and the colonization of 42 patients (60% of all colonized patients). The strain with one of those genotypes appeared to be endemic to the BWC and developed multidrug resistance (MDR) at the end of the study period, whereas the strain with the other genotype was antibiotic susceptible but resistant to silver sulfadiazine (SSD(r)). The MDR strain was found at a higher frequency in sputum samples than the SSD(r) strain, which showed a higher prevalence in burn wound samples, suggesting that anatomic habitat selection was associated with adaptive resistance to antimicrobial drugs. Repeated and thorough surveys of the hospital environment failed to detect a primary reservoir for any of those genotypes. Cross-acquisition, resulting from insufficient compliance with infection control measures, was the major route of colonization in our BWC. In addition to the AFLP pattern and serotype, analysis of the nucleotide sequences of three (lipo)protein genes (oprI, oprL, and oprD) and the pyoverdine type revealed that all predominant strains except the SSD(r) strain belonged to recently identified clonal complexes. These successful clones are widespread in nature and therefore predominate in the patient population, in whom variants accumulate drug resistance mechanisms that allow their transmission and persistence in the BWC.

Anti-Infective Agents, Local↗
PubMed1978

Continuous measurement of gas partial pressures in intracerebral tissue.

A mass spectrograph technique has been developed for measurement of physiological gas partial pressures locally in the brain. The sampling cannula is implanted stereotaxically and remains in situ for several weeks. It is a thin cylinder in shape, and is covered with a thin polyethylene membrane across which gas molecules can be sampled continuously. The conductance of this membrane is well adapted to the limited rate of replacement of gas molecules afforded by the cerebral tissue, hence there is no depletion around the cannula; this depletion has until now been the major problem of this technology. The present technique provides a continuous measurement with fast response time, which is directly proportional to the partial pressures of the gases. The variations can be expressed as a percentage of the base-line value.

Animals↗