Calculation of Mie derivatives.

Analytical expressions are found for the derivatives of commonly used Mie scattering parameters, in particular the absorption and the scattering efficiencies, and for the angular intensity functions. These expressions are based on the analytical derivatives of the Mie scattering amplitudes a(n) and b(n) with respect to the particle size parameter and complex refractive index. In addition, analytical derivatives are found for the volume absorption and scattering coefficients, as well as for the intensity functions of a population of particles with log normal size distribution. These derivatives are given with respect to the total number density, to the median radius and spread of the distribution, and to the refractive index. Comparison between analytically and numerically computed derivatives showed the analytical version to be 2.5 to 6.5 times as fast for the single-particle and particle-distribution cases, respectively.

Role of CO diffusing capacity during exercise in the preoperative evaluation for lung resection.

We conducted a prospective study to evaluate whether lack of an adequate increase in diffusing capacity for carbon monoxide (DL(CO)) during exercise is associated with a greater postoperative complication rate after lung resection. We used the three-equation method (3EQ-DL(CO)), a modification of the single breath DL(CO) technique to determine DL(CO) during exercise in 57 patients undergoing lung resection at Vancouver General Hospital from October 1998 to May 1999. 3EQ-DL(CO) was determined during steady-state exercise at 35% and 70% of the maximal workload reached in a progressive exercise test. Maximal oxygen uptake (VO(2)max), DL(CO) at rest, and the increase in DL(CO) during exercise were compared in relation to postoperative complications. Patients with complications had lower resting values of DL(CO) (R-DL(CO)), a smaller increase in DL(CO) from rest to 70% of maximal workload expressed as a percent of the predicted DL(CO) at rest ([70% - R]-DL(CO)%), and a lower VO(2)max than did patients without complications. Results suggested that (70% - R)-DL(CO)% was the best preoperative predictor of postoperative complications; a cutoff limit of 10% was the best index to identify complications, yielding a complication rate of 100% in patients with (70% - R)-DL(CO)% < 10% as compared with a complication rate of 10% in patients with (70% - R)-DL(CO)% >/= 10% (sensitivity = 78%, specificity = 100%). Patients who do not increase their DL(CO) sufficiently during exercise ([70% - R]-DL(CO)% < 10%) have a greater complication rate after lung resection.

Construction and characterization of two anti-sweetener single chain antibodies using radioligand binding, fluorescence and circular dichroism spectroscopy.

Two single-chain antibodies (scFv) that bind the superpotent sweetener ligand, NC-174, were generated from mouse monoclonal antibodies (mAb) NC6.8 (IgG, kappa) and NC10.14 (IgG, lambda). These scFv were constructed by cloning the variable region sequences of the mAb, connecting them in tandem with a 25-amino-acid polypeptide linker, and expressing them in E. coli using the pET-11a system. The recombinant proteins were purified using Ni(2+)-NTA-agarose by virtue of a hexahistidine sequence introduced to the C-terminus of the heavy chain variable region during the cloning process. The secondary structure and ligand binding properties of the two scFv, the parent mAbs and proteolytically derived Fab fragments were examined using radioligand binding, circular dichroism (CD) and fluorescence spectroscopy. The far-UV CD spectra of both scFv possessed predominantly beta character, as did those of the Fab, and the near-UV CD spectral data for scFvNC10.14, NC6.8 and NC10.14 Fab indicated that chromophore perturbation occurred upon ligand binding. The affinity constants determined for the two scFv, Fab and mAb were nearly equivalent.

Nonuniformity of diffusing capacity from small alveolar gas samples is increased in smokers.

BACKGROUND: Although centrilobular emphysema, and small airway, interstitial and alveoli inflammation can be detected pathologically in the lungs of smokers with relatively well preserved lung function, these changes are difficult to assess using available physiological tests. Because submaximal single breath washout (SBWSM) manoeuvres improve the detection of abnormalities in ventilation inhomogeneity in the lung periphery in smokers compared with traditional vital capacity manoeuvres, SBWSM manoeuvres were used in this study to measure temporal differences in diffusing capacity using a rapid response carbon monoxide analyzer. OBJECTIVE: To determine whether abnormalities in the lung periphery can be detected in smokers with normal forced expired volumes in 1 s using the three-equation diffusing capacity (DLcoSB-3EQ) among small alveolar gas samples and whether the abnormalities correlate with increases in peripheral ventilation inhomogeneity. PARTICIPANTS AND DESIGN: Cross-sectional study in 21 smokers and 21 nonsmokers all with normal forced exhaled flow rates. METHODS: Both smokers and nonsmokers performed SBWSM manoeuvres consisting of slow inhalation of test gas from functional residual capacity to one-half inspiratory capacity with either 0 or 10 s of breath holding and slow exhalation to residual volume (RV). They also performed conventional vital capacity single breath (SBWVC) manoeuvres consisting of slow inhalation of test gas from RV to total lung capacity and, without breath holding, slow exhalation to RV. DLcoSB-3EQ was calculated from the total alveolar gas sample. DLcoSB-3EQ was also calculated from four equal sequential, simulated aliquots of the total alveolar gas sample. DLcoSB-3EQ values from the four alveolar samples were normalized by expressing each as a percentge of DLcoSB-3EQ from the entire alveolar gas sample. An index of variation (DI) among the small-sample DLcoSB-3EQ values was correlated with the normalized phase III helium slope (Sn) and the mixing efficiency (Emix). RESULTS: For SBWSM, DI was increased in smokers at 0 s of breath holding compared with nonsmokers, and correlated with age, smoking pack-years and Sn. The decrease in DI with breath holding was greater in smokers and correlated with the change in Sn with breath holding. For SBWVC manoeuvres, there were no differences due to smoking in Sn or Emix, but DI was increased in smokers and correlated with age and smoking pack-years, but not with Sn. CONCLUSIONS: For SBWSM manoeuvres the increase in DI in smokers correlated with breath hold time-dependent increases in Sn, suggesting that the changes in DI reflected the same structural alterations that caused increases in peripheral ventilation inhomogeneity. For SBWVC manoeuvres, the increase in DI in smokers was not associated with changes in ventilation inhomogeneity, suggesting that the effect of smoking on DI during this manoeuvre was due to smoke-related changes in alveolar capillary diffusion, rather than due solely to alterations in the distribution of ventilation.

Coping with cancer.

In summary, the manner in which an individual and his or her family and friends adapt to the diagnosis of cancer is quite individual and complicated, and depends on a number of factors. It is important that patients realize that they should acknowledge their feelings to their physicians, family and friends so that these feelings can be validated. In this way they can be helped to find resources to enhance their coping abilities. There are many support groups that are now available for patients in various areas of cancer treatment. Efforts are underway to bring more of these issues to light in medical training so that physicians may be better prepared to strengthen a person's ability to cope with cancer and to live to the fullest extent possible.

The effect of oral creatine monohydrate supplementation on running velocity.

Creatine supplementation has been shown to augment muscle PCr content and increase the rate of ATP resynthesis. Thus, we hypothesized that creatine supplementation might enhance sprinting performance. Eighteen subjects completed both of two testing sessions (control and postsupplement) 1 week apart, wherein they sprinted three 60-m distance trials that were recorded with videotape. Following the control session, for 7 days, subjects in the treatment group ingested a creatine-glucose mixture, while the placebo group consumed a glucose powder, followed by the postsupplementation session. Velocities of the subjects through three testing zones within the 60-m sprint were calculated from the videotape. Resultant velocities were analyzed using a MANOVA with a 2 x 2 x 3 x 3 (Group x Session x Trial x Zone) design. Results indicated that there were no statistically significant main or interaction effects on velocity between groups for session, trial, or zone. These data do not support the hypothesis that supplementary creatine ingestion will enhance velocity during the early or latter segments of a 60-m sprint.

Adolescent development and the emergence of sexuality.

Adolescence is a time of significant opportunity and significant challenge. Challenges can be difficult for some adolescents, which may result in problems that are expressed as affective disturbances or by the adolescent's participation in risk-taking behaviors. This review emphasizes the changes in biopsychosocial development during adolescence. We specifically address aspects of individual change during the adolescent decade (e.g., biological, cognitive, psychosocial, and sexual development) as well as the effects of context on normal development and responses to challenges during this period. Predispositions or vulnerabilities present prior to a developmental transition may be exacerbated by the transition. Adolescents can become healthy adults with the encouragement to develop gradually by limiting the simultaneous changes they experience, where possible, and by supporting healthy development through developmentally appropriate activities and supportive relationships with adults and peers.

Measurement of temporal changes in DLSBCO-3EQ from small alveolar samples in normal subjects.

The dynamic changes in CO concentration [CO] during a single breath could be influenced by topographic inhomogeneity in the lung or by peripheral inhomogeneity due to a gas mixing resistance in the gas phase of the lung or to serial gradients in gas diffusion. Ten healthy subjects performed single-breath maneuvers by slowly inhaling test gas from functional residual capacity to one-half inspiratory capacity and slowly exhaling to residual volume with target breath-hold times of 0, 1.5, 3, 6, and 9 s. We calculated the three-equation single-breath diffusing capacity of the lung for CO (DLSBCO-3EQ) from the mean [CO] in both the entire alveolar gas sample and in four successive equal alveolar gas samples. DLSBCO-3EQ from the entire alveolar gas sample was independent of breath-hold time. However, with 0 s of breath holding, from early alveolar gas samples DLSBCO-3EQ was reduced and from late alveolar gas samples it was increased. With increasing breath-hold time, DLSBCO-3EQ from the earliest alveolar gas sample rapidly increased, whereas from the last alveolar gas sample it rapidly decreased such that all values from the small alveolar gas samples approached DLSBCO-3EQ from the entire alveolar sample. These changes correlated with ventilation inhomogeneity, as measured by the phase III He concentration slope and the mixing efficiency, and were larger for maneuvers with inspired volumes to one-half inspiratory capacity vs. total lung capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ventilation inhomogeneity on "intrabreath" measurements of diffusing capacity in normal subjects.

In normal seated subjects we increased single-breath ventilation inhomogeneity by changing both the preinspiratory lung volume and breath-hold time and examined the ensuing effects on two different techniques of measuring the diffusing capacity of the lung for carbon monoxide (DLCO). We measured the mean single-breath DLCO using the three-equation method (DLCOSB-3EQ) and also measured DLCO over discrete intervals during exhalation by the "intrabreath" method (DLCOexhaled). We assessed the distribution of ventilation using the normalized phase III slope for helium (SN). DLCOSB-3EQ was unaffected by preinspiratory lung volume and breath-hold time. DLCOexhaled increased with increasing preinspiratory lung volume and decreased with increasing breath-hold time. These changes correlated with the simultaneously observed changes in ventilation inhomogeneity as measured by SN (P < 0.01). We conclude that measurements of DLCOexhaled do not accurately reflect the mean DLCO. Intrabreath methods of measuring DLCO are based on the slope of the exhaled CO concentration curve, which is affected by both ventilation and diffusion inhomogeneities. Although DLCOexhaled may theoretically provide information about the distribution of CO uptake, the concomitant effects of ventilation nonuniformity on DLCOexhaled may mimic or mask the effects of diffusion nonuniformity.

Effects of ventilation inhomogeneity on DLcoSB-3EQ in normal subjects.

In patients with airflow obstruction, we found that ventilation inhomogeneity during vital capacity single-breath maneuvers was associated with decreases in the three-equation single-breath CO diffusing capacity of the lung (DLcoSB-3EQ) when breath-hold time (tBH) decreased. We postulated that this was due to a significant resistance to diffusive gas mixing within the gas phase of the lung. In this study, we hypothesized that this phenomenon might also occur in normal subjects if the breathing cycle were altered from traditional vital capacity maneuvers to those that increase ventilation inhomogeneity. In 10 normal subjects, we examined the tBH dependence of both DLcoSB-3EQ and the distribution of ventilation, measured by the mixing efficiency and the normalized phase III slope for helium. Preinspiratory lung volume (V0) was increased by keeping the maximum end-inspiratory lung volume (Vmax) constant or by increasing V0 and Vmax. When V0 increased while Vmax was kept constant, we found that the tBH-independent and the tBH-dependent components of ventilation inhomogeneity increased, but DLcoSB-3EQ was independent of V0 and tBH. Increasing V0 and Vmax did not change ventilation inhomogeneity at a tBH of 0 s, but the tBH-dependent component decreased. DLcoSB-3EQ, although independent of tBH, increased slightly with increases in Vmax. We conclude that in normal subjects increases in ventilation inhomogeneity with increases in V0 do not result in DLcoSB-3EQ becoming tBH dependent.

Effect of volume history on changes in DLcoSB-3EQ with lung volume in normal subjects.

The purpose of this study was to determine the relationship between the three-equation diffusing capacity for carbon monoxide (DLcoSB-3EQ) and lung volume and to determine how this relationship was altered when maneuvers were immediately preceded by a deep breath. DLcoSB-3EQ maneuvers were performed in nine healthy subjects either immediately after a deep breath or after tidal breathing for 10 min. The maneuvers consisted of slow inhalation of test gas from functional residual capacity to 25, 50, 75, or 100% of the inspiratory capacity and, without breath holding, slow exhalation to residual volume. After either a deep breath or tidal breathing, we found that DLcoSB-3EQ decreased nonlinearly with decreasing lung volume. At all lung volumes, DLcoSB-3EQ was significantly greater when measured after a deep breath than after tidal breathing. This effect increased as lung volume decreased, so that the greatest difference between DLcoSB-3EQ after a deep breath and that after tidal breathing occurred at the lowest lung volume. We conclude that a deep breath or spontaneous sigh has a role in reestablishing the pathway for gas exchange during tidal breathing.

Identification of spliced baculovirus RNAs expressed late in infection.

Previous to this study, the Autographa californica multicapsid nuclear polyhedrosis virus (AcMNPV) was known to express only one spliced RNA (spliced IE1 or IE0). We have conducted an analysis of RNA expressed during infection of Spodoptera frugiperda cells with AcMNPV and have identified a set of five additional spliced RNAs expressed late in infection. A reverse transcription-polymerase chain reaction analysis was used to confirm the identification of the LS (late, spliced) RNAs. S1 nuclease and primer extension analyses were used to map the transcription initiation sites of LS RNAs. LS1 and LS2 initiated at positions -138 and -117, respectively (relative to the IE0 +1 transcription start site). Both LS1 and LS2 contain an additional cistron potentially encoding a small, highly basic polypeptide. LS3 (-79), LS4 (-22), and LS5 (+51/52) RNAs encode only the predicted downstream IE0 ORF. Although several baculovirus late gene consensus transcription initiation sites (ATAAG) were identified within this region, only LS5 initiated at one of these conserved motifs. An S1 nuclease analysis was done to determine whether unspliced precursors of LS RNAs could be detected. Early in infection, a greater proportion of IE0 RNA was detected in the spliced form; however, during the late phase of infection a significantly greater amount of unspliced precursor forms of LS RNAs was observed.

Patients with localized pancreatic adenocarcinoma in central Mississippi: a retrospective analysis of survival.

Factors influencing the survival of central Mississippi patients with adenocarcinoma of the pancreas were analyzed by a retrospective analysis of the two largest tumor registries in the state. The authors report that this Mississippi data agree with very recent reports describing significant benefit from chemoradiotherapy in localized disease, and suggests a less fatalistic attitude of the medical community towards localized pancreatic carcinoma is appropriate.

Pulmonary diffusing capacity in adult cystic fibrosis: reduced positional changes are partially reversed by hyperoxia.

In seated adult cystic fibrosis (CF) patients, vascular recruitment of the relatively normal regions of the pulmonary circulation could occur in response to vascular destruction or hypoxia elsewhere in the pulmonary vasculature, thus limiting overall reductions in the single breath CO diffusing capacity (DLcoSB) with advancing disease. The purpose of this study was to determine the extent to which pulmonary capillary recruitment limits reductions in DLcoSB in seated adult cystic fibrosis patients, to define the role of hypoxia, and to develop strategies to improve detection of diffusion abnormalities in this disease. In normal subjects and adult CF patients breathing room air, and in a subgroup, after breathing both 40% and 100% O2 for 20 min, we measured changes (compared to sitting) in the three equation DLcoSB by changing transvascular pressure either with 15 degrees head down position (15 degrees HD), or with high negative inspiratory pressure (HNIP). In CF patients breathing room air, the changes in DLcoSB with both 15 degrees HD and HNIP were significantly smaller (p less than 0.01) than in controls and the positional changes correlated with the degree of airway obstruction. Although CF patients had no significant positional changes in diffusional resistance (1/DLcoSB) breathing room air, the positional changes in 1/DLcoSB after breathing 100% O2 for 20 min were similar in magnitude to the positional changes in normal subjects. We conclude that compensatory pulmonary capillary recruitment occurs in the relatively normal regions of the pulmonary vasculature breathing room air in the resting seated position in CF patients, thus minimizing reductions in DLcoSB in the seated position. This accounts for reduced responses of DLcoSB to both position and HNIP. The improved positional changes in 1/DLcoSB breathing hyperoxic gas mixtures in CF patients suggests that the vascular recruitment breathing room air is partly due to hypoxic vasoconstriction rather than due solely to fixed pathological changes in the pulmonary vasculature.

Effect of a deep breath on gas mixing and diffusion in the lung.

We examined the effect of a previous deep breath on both inert gas mixing and the single breath diffusing capacity (DLCOSB) during submaximal single breath maneuvers in normal subjects. Single breath washouts were performed either immediately after a deep breath or after breathing tidally for 10 min. Maneuvers consisted of inhaling test gas from functional residual capacity to 50% inspiratory capacity and, after either 0 or 6 s of breath holding, exhaling slowly back to residual volume. We measured the Fowler dead space, the Phase III slope of the alveolar plateau of the He washout (delta He/L), the amplitude of the cardiogenic oscillations (Oc), closing capacity, mixing efficiency (Emix) and DLCOSB using the three equation method. For maneuvers immediately after a deep breath we found that delta He/L was steeper and the Oc were larger for washouts with 6 s but not 0 s of breath holding, while Emix was significantly lower and DLCOSB significantly higher for both the 0 s and the 6 s breath holding maneuvers. We conclude that a deep breath increases DLCOSB but simultaneously also increases convective-dependent inhomogeneity in the lung.

Focal glomerulosclerosis in Hodgkin's disease necessitating peritoneal dialysis.

A 16-year-old white boy had nephrotic syndrome due to focal segmental glomerulosclerosis six months before the diagnosis of Hodgkin's disease was established. Peritoneal dialysis was necessary for volume control after one month of unsuccessful therapy with high doses of corticosteroids. Nephrosis remitted after two courses of chemotherapy.

Respiratory symptoms and alterations in pulmonary function tests in swine producers in Saskatchewan: results of a survey of farmers.

To determine whether farmers who produced swine in animal confinement chambers in Saskatchewan were at increased risk of developing respiratory dysfunction, we carried out a respiratory health questionnaire and spirometric pulmonary function test measurements, including forced expired volume in 1 second (FEV1), forced vital capacity (FVC), and the ratio of FEV1 to FVC (FEV1/FVC x 100), on 504 farmers who indicated that they raised swine, and 448 rural-dwelling nonfarming control subjects. Swine producers had lower values for FVC and FEV1 than did the control subjects. However, FEV1/FVC x 100 was somewhat higher in the swine producers. The reduction in FEV1 with retained FEV1/FVC ratio is suggestive of restrictive disease. However, the fact that the FEV1/FVC ratio is only modestly higher in swine producers than in control subjects suggests that there may be a mixed restrictive/obstructive condition in these workers.

Surgery in small cell lung cancer.

Surgery in small cell lung cancer (SCLC) was abandoned in the late 1960s but is currently being cautiously reassessed, after the Armed Forces Asymptomatic Pulmonary Nodule Study demonstrated an unexpectedly prolonged 5-year survival (36%) with surgery. Subsequent prospective studies have reported five-year survival following resection in 22 to 83% of patients with Stage I disease and in 0 to 50% of patients with Stages II and III disease. Ten percent of patients with SCLC may be amenable to this approach. Additional patients may become candidates for resection following intensive combination chemotherapy. The optimal postoperative management remains unsettled. Combination chemotherapy and prophylactic cranial irradiation is recommended following complete resection. Postoperative thoracic irradiation may benefit patients with pathologically involved mediastinal nodes. Correlation of clinical response with our new understanding of the molecular biology of SCLC may further improve our approach to this disease.

Respiratory symptoms and pulmonary function in farmers.

A questionnaire was given to 1,824 farmers and 556 control subjects in Saskatchewan to assess respiratory health and pulmonary function tests. With data corrected for age and smoking, farmers were found to have increased prevalences of the respiratory symptoms of phlegm, wheeze, shortness of breath, and the condition of chronic bronchitis. In addition, farmers had significantly lower values for the pulmonary function test variables forced vital capacity (FVC), forced expired volume in one second (FEV1) and maximum midexpiratory flow rate. However, the FEV1/FVC ratio was slightly but significantly greater in farmers than in control subjects. These findings suggest an increase in respiratory symptoms in farmers compared with rural control subjects who are not farmers and a decrease in lung volume and expired flow rates. The slightly high FEV1/FVC ratio may indicate a mixed obstructive and restrictive picture.