Spectral properties of photonic crystal double heterostructure resonant cavities.

Spectral properties of photonic crystal double heterostructure resonant cavities are calculated numerically using the three-dimensional finite-difference time-domain method. Resonance frequencies and quality factors are reported for various bound states that form near stationary points in the photonic crystal dispersion diagram. The associated electric field spatial profiles are presented indicating potential for in-plane laser optimization. In addition, Fabry-Perot oscillations are observed in the spectra.

Photonic crystal lasers in InGaAsP on a SiO(2)/Si substrates and its thermal impedance.

Two-dimensional photonic crystal defect lasers in InGaAsP membranes directly bonded to a SiO(2)/Si substrate have been demonstrated. Lasing at wavelengths near 1550 nm was obtained with incident threshold pump powers as low as 1.5 mW. Good agreement between experimental data and three-dimensional finite-difference time-domain (FDTD) simulation was achieved. The thermal impedance of this laser is also characterized.

Hillside study of risk and early detection in schizophrenia.

BACKGROUND: The Hillside Study of Risk and Early Detection in Schizophrenia is a prospective study of young probands (ages 14-28) and their at-risk siblings (ages 14-24). A major goal is the identification of early predictors of illness that will facilitate intervention. The project design and pilot study are discussed. METHOD: Fifteen adolescents were compared to 14 typical age-of-onset adults, all undergoing their first hospitalisation for schizophrenia. RESULTS: There were no differences between adolescents and adults on any of the measures administered (i.e. attention, eye tracking, neurocognitive or clinical). In addition, for the sample overall, no association was found between neurocognitive functions and clinical state, either at admission or after treatment. CONCLUSIONS: Individuals with adolescent onset of schizophrenia are considered to be representative of schizophrenia in general. Furthermore, neurocognitive deficits and clinical symptoms are concluded to be two independent classes of risk indicators.

BLEED: a classification tool to predict outcomes in patients with acute upper and lower gastrointestinal hemorrhage.

OBJECTIVE: To develop an outcome prediction tool (BLEED: ongoing bleeding, low systolic blood pressure, elevated prothrombin time, erratic mental status, unstable comorbid disease) for clinical use in patients with either acute upper or acute lower gastrointestinal (GI) hemorrhage. DESIGN: A cohort study. SETTING: Barnes Hospital and Jewish Hospital, two private university-affiliated teaching hospitals in St. Louis, MO. PATIENTS: Four hundred sixty-five patients with either acute upper or acute lower GI hemorrhage admitted from the emergency department. INTERVENTIONS: Admission of patients to the intensive care unit or hospital ward was determined by emergency department physicians, without use or knowledge of BLEED criteria. Patients meeting any BLEED criteria at their initial assessment in the emergency department were classified as "high-risk." All other patients were classified as "low-risk." MEASUREMENTS AND MAIN RESULTS: The main outcome measure was the occurrence of an inhospital complication, defined as recurrent GI hemorrhage, surgery to control the source of hemorrhage, and hospital mortality. Patients classified as high-risk had significantly greater rates of inhospital complications at both Barnes Hospital (relative risk, 2.47; 95% confidence interval, 1.38 to 4.44; p < .001) and Jewish Hospital (relative risk, 8.94; 95% confidence interval, 3.92 to 20.41; p < .001) compared with patients classified as low-risk. Patients classified as high-risk at either hospital were significantly more likely to develop additional organ system derangements, require a greater number of transfused units of packed red blood cells, and have longer hospital stays compared with patients classified as low-risk (p < .006). The BLEED classification also identified a greater frequency of intensive care admission for both low-risk (RR, 4.21; 95% Cl, 2.24 to 7.89) and high-risk (relative risk, 1.58; 95% confidence interval, 1.23 to 2.02) patients at Barnes Hospital compared with those patients at Jewish Hospital, although no beneficial effects on patient outcome were reported. CONCLUSIONS: The BLEED classification, applied at initial emergency department evaluation and before admission, predicts hospital outcomes for patients with acute upper or lower GI hemorrhage. This outcome prediction tool also identified variations in intensive care utilization between two hospitals.

Safety and yield of transbronchial biopsy in mechanically ventilated patients.

OBJECTIVE: To evaluate the safety and diagnostic yield of transbronchial biopsy performed in mechanically ventilated patients. DESIGN: Retrospective, cohort analysis. SETTING: A university-affiliated teaching hospital. PATIENTS: Seventy-one consecutive, mechanically ventilated patients requiring lung tissue examination. INTERVENTIONS: Transbronchial lung biopsy. MEASUREMENTS AND MAIN RESULTS: We evaluated complications associated with transbronchial biopsy, diagnostic yield of the procedure, and changes in patient management based on the results of the transbronchial lung biopsies. Eighty-three transbronchial lung biopsy procedures were performed in this patient cohort. Complications associated with these procedures included the following: ten (14.3%) pneumothoraces in patients without preexisting chest tubes; five (6.0%) episodes of bronchial hemorrhage of > 30 mL; transient oxygen desaturation to < 90% in seven (8.4%) patients; hypotension with a mean arterial pressure of < 60 mm Hg in six (7.2%) patients; and three (3.6%) episodes of tachycardia, with a heart rate of > 140 beats/min. No patient deaths, episodes of pneumonia, or sepsis could be attributed to the transbronchial lung biopsy procedures. Specific histologic diagnoses were made with 29 (34.9%) of the transbronchial biopsies, and patient management was changed as a direct result of the lung tissue examination in 34 (41.0%) instances. Pathologic correlation between the transbronchial biopsy specimens and lung tissue obtained by open-lung biopsy or post mortem examination occurred in 11 (84.6%) of 13 paired samples. CONCLUSION: Transbronchial lung biopsy can be performed with an acceptable risk and reasonable diagnostic yield in certain types of mechanically ventilated patients, often obviating the need to perform open-lung biopsy.

The impact of gender on outcome from mechanical ventilation.

OBJECTIVE: To determine the relation of gender to outcome for patients requiring mechanical ventilation. DESIGN: A prospective cohort study. SETTING: Medical and surgical ICUs in two university-affiliated teaching hospitals. PATIENTS: Three hundred fifty-seven patients requiring mechanical ventilation. INTERVENTIONS: Prospective patient surveillance and data collection. MEASUREMENTS AND RESULTS: The primary outcome measure was hospital mortality. Secondary outcome measures included need for reintubation, hospital and ICU length of stay, duration of mechanical ventilation, and hospital charges. The hospital mortality rate for women (n = 189) was significantly greater than the hospital mortality rate for men (n = 168) (28.0% vs 17.3%; p = 0.016). This difference in hospital mortality was observed despite similar baseline demographic characteristics, severity of illness, indications for mechanical ventilation, and number of dysfunctional organ systems in these two groups of patients. The duration of mechanical ventilation and ICU length of stay was also significantly longer for female patients compared with male patients (p < or = 0.056). In a logistic-regression analysis, female gender was found to be independently associated with hospital mortality (adjusted odds ratio [AOR] = 2.38; 95% confidence interval [CI] = 1.70 to 3.35; p = 0.010). The presence of ARDS (AOR = 10.69; 95% CI = 5.86 to 19.51; p < 0.001), the number of dysfunctional organ systems (AOR = 2.07; 95% CI = 1.78 to 2.41; p < 0.001), Acute Physiology and Chronic Health Evaluation (APACHE) II predicted mortality (AOR = 1.15; 95% CI = 1.11 to 1.19; p < 0.001), and patient age (AOR = 1.04; 95% CI = 1.03 to 1.06; p < 0.001) were also found to be independently associated with hospital mortality. The number of dysfunctional organ systems present at the start of mechanical ventilation was the major independent predictor of hospital mortality (54% of total explanatory power). Patient gender was the least important independent predictor of hospital mortality (5% of total explanatory power). CONCLUSIONS: In this patient cohort, women requiring mechanical ventilation were at greater risk for hospital mortality than men. Physicians should be aware that outcome differences according to gender can occur when evaluating or designing clinical trials involving mechanically ventilated patients. Future studies are necessary to determine the general applicability of these findings and to identify explanations for such observed gender-specific differences in outcome.

Attention and clinical symptoms in schizophrenia.

Attentional deficits, long established to characterize patients with schizophrenia spectrum disorders, have traditionally been regarded as part of the disorder's clinical syndrome. In this paper we provide evidence to indicate that: a) impaired attention is a dimension of schizophrenia that is independent of clinical state, and b) that attention does not appear to respond to the medication (i.e. standard neuroleptics) most typically used to treat clinical symptoms. Since intact attention and other cognitive processes appear critical to successful functioning in the community after hospital discharge, these findings have major implications for treatment.

Pulmonary complications of liver transplantation.

The preoperative pulmonary evaluation of organ transplant candidates involves the diagnosis of unexplained pulmonary infiltrates or symptoms, interpretation of pulmonary function abnormalities, and an assessment of surgical risk. Pretransplant pulmonary considerations in patients with end-stage hepatic diseases relate primarily to hypoxemia from poorly understood intrapulmonary vascular dilatations, mechanical dysfunction, and states of increased extravascular lung water. Except in severe cases, however, these generally do not prohibit liver transplantation, and even are likely to improve after transplant surgery. Early postoperative complications may be categorized as those expected from extensive intra-abdominal surgery that requires significant volume resuscitation, which typically are managed in the usual manner for those clinical situations. As immunosuppression begins to have an effect, the LTx recipient becomes susceptible to the same opportunistic infectious organisms (with their frequent pulmonary involvement) that cause significant morbidity and mortality in recipients of other solid organ transplants. Because many of the immunosuppressive agents also are the same, noninfectious side effects such as pulmonary edema and malignancy also are similar. As with all immunocompromised patients, prophylaxis, when possible, persistent infection surveillance, and an aggressive diagnostic and therapeutic approach help decrease the impact of pulmonary dysfunction in LTx recipients.

Nephrobronchial fistula and lung abscess resulting from nephrolithiasis and pyelonephritis.

There are multiple etiologies reported as causes of lung abscess; however, this differential rarely includes intra-abdominal abnormalities other than extension of a hepatic process. We describe a patient who was found to have a lung abscess and empyema resulting from the development of a nephrobronchial fistula secondary to nephrolithiasis and pyelonephritis. The patient had no urinary symptoms or known abdominopelvic infection and the etiology of lung abscess was only incidentally discovered after chest CT revealed extension of pleural fluid below the diaphragm.

Lymphangiomyomatosis recurrence in the allograft after single-lung transplantation.

The evolution of lung transplantation has offered an additional treatment option for patients with a variety of end-stage lung diseases, including some with systemic disorders. Lymphangiomyomatosis (LAM) is a multisystem disease of premenopausal women. The lung is the most frequently involved vital organ, and respiratory failure is the most common case of death. A small number of patients with LAM have undergone lung transplantation. This report describes a case of recurrent LAM in the allograft after single lung transplantation and discusses the implications of this finding.

The factor structure of ADHD items in DSM-III-R: internal consistency and external validation.

Previous research employing factor-analytic procedures to study the underlying dimensions of DSM-III attention deficit disorder with hyperactivity (ADDH) symptoms have consistently supported a two-factor model. Revision of the structure of the ADHD diagnosis in DSM-III-R, as well as inclusion of new items, has raised the question of comparability of the two diagnoses. To explore the significance of these changes, teacher ratings of DSM-III ADDH items and DSM-III-R ADHD items of 85 nonreferred school children were factor-analyzed to determine their underlying factor structures. A similar two-factor solution was obtained for each diagnostic scale. The factors consisted of items believed to reflect inattention and hyperactivity-impulsivity constructs. These factors were further evaluated against results of a cognitive test battery to ascertain whether objective, external validation could be demonstrated. The hyperactivity-impulsivity factor scores were related to continuous performance test measures of response inhibition, while inattention-disorganization factor scores were related to measures of attention and visual search. Implications for assessment and diagnosis of ADHD are discussed.

Psychometric differentiation of conduct disorder and attention deficit disorder with hyperactivity.

Using a retrospective chart review procedure, children diagnosed as having attention deficit disorder with hyperactivity (ADDH), conduct disorder (CD), and ADDH+CD, as defined by DSM-III, were compared on measures of cognitive and academic functioning as well as on a continuous performance test (CPT). The groups did not differ in age or IQ, but children in the ADDH and ADDH+CD groups missed significantly more target stimuli on the CPT and performed significantly poorer on measures of academic achievement than did the pure CD group. However, poor CPT performance was not accounted for by learning problems. These findings in clinically referred patient groups are consistent with dimensional and epidemiological studies that suggest that ADDH may be a cognitively based disorder, whereas CD children are characterized by behavioral symptoms with fewer cognitive and learning deficits.

Estimation of small bowel transit time following colectomy and ileal reservoir construction.

A study was carried out to evaluate the breath hydrogen test as a method of estimating small bowel transit in patients with an ileal pouch and to determine whether gut transit time influenced functional outcome. Twelve patients with an ileal reservoir and ten control subjects ingested a test meal of 400 ml chicken soup, 20 g lactulose and 50 ml dilute barium solution. Concurrent breath hydrogen testing and radiological screening was carried out until the head of the test meal reached the ileal pouch or caecum. At the time that the test meal arrived in the pouch, faecal anaerobic bacterial counts were obtained. Pouch compliance, functional capacity and anal sphincter pressures were also measured. While there was an excellent correlation between radiological and breath hydrogen measures of orocaecal transit time in controls (P less than 0.001), no such relationship was found for oropouch transit. Four of the 12 patients with a pouch produced no hydrogen after test meal ingestion, while in two other such patients breath hydrogen peaks occurred when the head of the meal was in the jejunum. The magnitude of the breath hydrogen rise in patients with an ileal pouch correlated well with faecal anaerobic bacterial counts (P less than 0.01). The median (95 per cent confidence interval) radiological small bowel transit time was more rapid in patients with a pouch than in control subjects: 28 (23-33) versus 72 (46-86) min (P less than 0.01). Increased 24-h frequency of defaecation was associated with more rapid small bowel transit after ileal reservoir construction (P less than 0.01) but correlated with neither pouch capacity nor compliance. These data show that small bowel transit time may be a determinant of ileal pouch function but that breath hydrogen estimation of gut transit time in patients with an ileal reservoir is unreliable.

Current prevention concepts in child and adolescent psychiatry.

This paper has attempted to show how prevention in child and adolescent mental health has been neglected for years. It continues with a discussion of current concepts of prevention and chooses one risk factor, maternal mental disorder to focus on. A new concept in prevention--previewing--is addressed and its tremendous potential for primary prevention is considered. Finally, previewing and its use in the direct therapy of the older child is discussed.

Validation of hyperactive, aggressive, and mixed hyperactive/aggressive childhood disorders: a research note.

Eighty-five non-referred school children were divided into four groups based upon the IOWA Conners Teacher's Questionnaire: pure hyperactive (HYP), pure aggressive (AGG), mixed hyperactive/aggressive (HYP/AGG), and normal controls. The groups were compared on neurobehavioral tests believed to assess inattention and impulsivity. A continuous performance test indicated that the HYP group was more inattentive than the other groups and the HYP/AGG group was most impulsive. The AGG group did not differ from controls. The data support the distinction between HYP, AGG and HYP/AGG groups of children selected by the IOWA Conners.

Perturbation of upper gastrointestinal transit and antroduodenal motility by experimentally applied stress: the role of beta-adrenoreceptor mediated pathways.

A series of three experiments were performed on healthy adult volunteers to investigate the possible role played by beta-adrenoreceptor mediated pathways in the disturbance of human upper intestinal motor function by hand immersion in cold water. In the first experiment, (an extended pilot study on one individual), orocaecal transit of a standard meal was measured on 36 occasions with and without cold water stimulation and with and without a series of alpha and beta blocking drugs. Cold water stimulation consistently delayed transit in this individual, an effect which was attenuated by prior beta-blockade. In a double blind trial of the effect of beta-blocker atenolol v placebo on transit in nine individuals, a consistent reduction in the cold water induced transit delay was observed (p less than 0.01) independent of any direct effect of beta-blockade. In the third experiment seven individuals underwent repeated studies of antroduodenal pressure activity comparing the effects of cold and warm water stimulation with and without beta blockade to determine whether the observed transit effect could be related to an action on gastrointestinal motility. Cold water stimulation reduced antroduodenal motility, but no consistent effects of previous beta blockade were noted. These studies indicate the presence of a beta-adrenoreceptor mediated pathway in the cold water induced delay of orocaecal transit but not in the inhibition of gastroduodenal motility. Further studies are indicated to determine the site and mode of action of this transit effect more precisely.

Are ADDH and ADHD the same or different?

To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.

Cross-gender behavior and psychopathology in boy psychiatric outpatients.

One hundred 5- to 12-year-old boys referred for outpatient psychiatric evaluation were assessed for cross-gender behavior using the Child Behavior and Attitude Questionnaire (CBAQ) and the Child Game Participation Questionnaire (CGPQ), and for possible associated psychopathology using the Child Behavior Checklist (CBCL) and clinical psychiatric (DSM-III) diagnoses. On the two feminine scales of the CBAQ and CGPQ, 30 to 50% scored within defined clinical ranges. High feminine scale scorers did not have higher Total CBCL scores than lower feminine scale scorers, and scores on the feminine scales correlated minimally with scores on the CBCL broad and narrow-band behavior problem scales, except for a significant positive correlation with the Delinquent subscale. No particular clinical psychiatric diagnoses were significantly associated with high feminine scorers: however, high feminine behavior scorers tended to have more conduct problems and mixed adjustment disorders and less anxious and depressive psychopathology. Clinicians were not alert to the degree of cross-gender behavior found, perhaps due to the concomitant externalizing psychopathology and masculine behavior in these same patients.