Order-of-magnitude estimates of latency (time to appearance) and refill time of a cancer from a single cancer 'stem' cell compared by an exponential and a logistic equation.

BACKGROUND/AIM: The time required before a mass of cancer cells considered to have originated from a single malignantly transformed cancer 'stem' cell reaches a certain number has not been studied. Applications might include determination of the time the cell mass reaches a size that can be detected by X-rays or physical examination or modeling growth rates in vitro in order to compare with other models or established data. MATERIALS AND METHODS: We employed a simple logarithmic equation and a common logistic equation incorporating 'feedback' for unknown variables of cell birth, growth, division, and death that can be used to model cell proliferation. It can be used in association with free or commercial statistical software. RESULTS: Results with these two equations, varying the proliferation rate, nominally reduced by generational cell loss, are presented in two tables. The resulting equation, instructions, examples, and necessary mathematical software are available in the online appendix, where several parameters of interest can be modified by the reader www.uic.edu/nursing/publicationsupplements/tobillion_Anderson_Rubenstein_Guinan_Patel1.pdf. CONCLUSION: Reducing the proliferation rate by whatever alterations employed, markedly increases the time to reach 10(9) cells originating from an initial progenitor. In thinking about multistep oncogenesis, it is useful to consider the profound effect that variations in the effective proliferation rate may have during cancer development. This can be approached with the proposed equation, which is easy to use and available to further peer fine-tuning to be used in future modeling of cell growth.

Epidermal cell proliferation in calorie-restricted aging rats.

Calorie restriction (CR) has been known to produce many beneficial health effects, and lowered cell proliferation from CR has been shown to produce anti-cancer effects in some tissues. In this study the rate of epidermal cell proliferation in aging Fischer 344 rats from ad libitum fed (AL) and CR colonies was assessed in relation to changes in epidermal thickness with age. Proliferating cell nuclear antigen (PCNA) was detected using immunohistochemical method on paraffin sections in the epidermis of dorsal skin and footpad in these animals obtained from the National Institute on Aging. The proliferating cell index was compared with morphometric measurement of epidermis in young, young adult and old animals (six per group). Data were analyzed by Excel and SPSS 14.0 softwares for statistical evaluation. Two-way analysis of variance (ANOVA) was applied to data to test the effects of age, diet, and age-diet interaction. The following significant effects were noted: (I) age and age-diet effects in dorsal skin epidermal width, and PCNA; (II) age, and diet effect on footpad epidermal thickness, and PCNA index. There was a trend of increasing epidermal thickness in the dorsal skin in normally feeding aging rats which was depressed with CR in the two younger groups. PCNA index showed a trend of attrition from young to old. The thickness of epidermis in foot pad showed a curvilinear trend in both AL and CR groups with lowest mean values in the old group, and more predominant effect in CR-exposed animals. The proliferation index in the foot pad demonstrated a trend of reduction in old specimens with lower mean values in each corresponding CR age group. This report agrees with CR-inhibited cell proliferation reported in many organs by other investigators, and the observed results might have been caused by physiological or endocrine mechanisms affecting the epithelium in these calorie-restricted animals.

Subjective fatigue, influencing variables, and consequences in chronic obstructive pulmonary disease.

BACKGROUND: Fatigue is a common symptom of chronic obstructive pulmonary disease (COPD), but little is known about the specific nature of COPD-related fatigue and its impact on daily life. OBJECTIVES: To (a) describe characteristics of fatigue in people with COPD and (b) test a theoretically and empirically supported model of the relationships among subjective fatigue, dyspnea, functional performance, anxious and depressed moods, and sleep quality in people with COPD. METHODS: A cross-sectional descriptive study was conducted with 130 people with moderate to severe COPD. Measures included the following: a Numerical Rating Scale (NRS) for frequency, intensity, and distress of fatigue and dyspnea; Fatigue Assessment Instrument (FAI); Chronic Respiratory Disease Questionnaire (CRQ); Profile of Mood States (POMS); Pittsburgh Sleep Quality Index (PSQI); Functional Performance Inventory (FPI); and spirometry. Path analysis was used to examine the relationships among variables. RESULTS: Participants reported moderate amounts of fatigue, which was described as situation-specific, had considerable consequences, and was responsive to rest and sleep. Dyspnea was slightly greater than fatigue, as measured by the NRSs (p <.001), and there was a strong relationship between fatigue and dyspnea (r =.74, p < .001). Dyspnea, depressed mood, and sleep quality accounted for 42% of the variance in subjective fatigue. Fatigue, dyspnea, airflow obstruction, and anxious mood accounted for 36% of the variance in functional performance. CONCLUSIONS: Fatigue is an important problem that affects performance of daily activities in people with COPD. The relationships or interactions that exist among fatigue and other symptoms are complex.

Developmental patterns of physiological response to a multisensory intervention in extremely premature and high-risk infants.

OBJECTIVE: To compare the developmental patterns of heart rate (HR), respiratory rate (RR), and hemoglobin oxygen saturation (SaO2) of premature infants with and without central nervous system (CNS) injury, and evaluate whether a multisensory intervention altered this development. SAMPLE: Thirty-seven premature infants born at 23-26 weeks with normal head ultrasounds or at 24-32 weeks and diagnosed with periventricular leukomalacia (PVL) and/or intraventricular hemorrhage (IVH) were studied at 33-35 weeks postconceptional age. DESIGN: Infants were randomly assigned to control and experimental groups. The experimental group infants received auditory, tactile, visual, and vestibular (ATVV) multisensory intervention twice daily from 33 weeks postconceptional age (PCA) until hospital discharge. MAIN OUTCOME MEASURES: HR, RR, and SaO2 were continuously monitored during baseline, intervention, and the 30-minute postintervention period. RESULTS: Between 33 and 35 weeks PCA, control group infants with and without CNS injury and experimental group infants without CNS injury had a significant decrease in resting mean HR, whereas RR and SaO2 remained stable. The infants with PVL who received the intervention showed increases in HR even at rest. CONCLUSIONS: The absence of a weekly decline in HR for experimental group infants with PVL suggests that PVL may affect maturation of the autonomic nervous system and increase risk of decelerative HR changes and associated clinical compromise. Infants diagnosed with PVL should be closely monitored during procedures or interventions that may be stressful or involve handling. Further research is needed to tailor multisensory interventions for infants with PVL.

Pupil staging and EEG measurement of sleepiness.

The goal of this multi-method study was to examine the validity (accuracy) of the pupillometric Alertness Level Test (ALT) as a physiologic measure of sleepiness. The study used a pooled-time series-correlation design with 16 untreated narcolepsy (8 F, 8 M), 16 untreated obstructive sleep apnea (OSA) (7 F, 9 M) and 16 healthy control (8 F, 8 M) subjects. Participants underwent EEG/polysomnography testing using standard Multiple Sleep Latency Test electrode placement concurrent with the 15 min pupillometric ALT. EEG data were examined to determine if theta power (4-7 Hz) increased during 2-s periods of proportional pupil size decreases (pupil Stage 1, 95% or more of maximal pupil size to Stage 4, 65-74% of maximal size). Printed EEG records also were visually scored. Self-report sleepiness measures included the Pittsburgh Sleep Quality Index, the Profile of Mood States and the Epworth Sleepiness Scale. Within subject groups, theta power ratios significantly increased across pupil stages for the sleep disorder groups but not for controls (theta activity increased 42% for narcoleptic and 36% for OSA subjects). Between subject groups, the amount of theta activity was significantly greater for narcoleptic and OSA subjects than that for controls. Visual EEG scoring and self-report measures were usually consistent with objective findings. The ALT is convenient, easily repeatable and less technically demanding than EEG sleepiness measures, and it deserves more comprehensive testing as a valid measure of sleepiness.

The coronary artery bypass experience: gender differences.

OBJECTIVE: The primary purpose of this study was to examine differences between women and men on physical, social and psychological domains of health quality of life before, 1 month after, and 3 months after coronary artery bypass surgery. DESIGN: A prospective, longitudinal design was used. SETTING: The study was conducted at a Midwestern, 500-bed community hospital with an ongoing cardiothoracic surgical program. PARTICIPANTS: Forty pairs of women and men matched on age within 5 years and body surface area within 0.1m 2. INSTRUMENTS: The physical, social and psychological domains of health quality of life were assessed using the following instruments: Ferrans and Powers Quality of Life Index, Specific Activity Scale, Symptom Scale, Profile of Mood States, Overall Health Rating Index, and Personal Resource Questionnaire. RESULTS: Both women and men improved on physical and psychological measures following coronary artery bypass surgery. Compared with men, women reported more shortness of breath and depression and lower ratings of activity, vigor, and overall health. Measures of social support yielded little information. CONCLUSIONS: Despite matching for age and body surface area, women did not have as favorable an outcome after surgery as men. Continued research needs to further examine the interaction of physical outcomes and depression in women after coronary artery bypass surgery.

Histological evaluations following 1,064-nm Nd:YAG laser resurfacing.

BACKGROUND AND OBJECTIVES: The long pulse 1,064-nm Nd:YAG laser is used clinically to decrease rhytid formation. The dermal level at which this change occurs has not been established. This study attempts to answer these questions using a porcine skin model. STUDY DESIGN/MATERIALS AND METHODS: Non-randomized prospective experimental trial involving the domestic piglet treated serially with the long pulse 1,064-nm Nd:YAG laser. RESULTS: Collagen formation occurred at the level of the reticular dermis. After one laser treatment, a significant level of collagen formation was induced in the reticular dermis compared to controls. The greatest gain was observed after four laser treatments. Energy levels of 20, 30, 40, and 50 J/cm2 were evaluated. Although not statistically significant, 30 J/cm2 had the greatest effect on collagen formation. However, at 50 J/cm2, marked ablative changes to the epidermis were observed. CONCLUSIONS: The long pulse 1,064-nm Nd:YAG laser induces collagen formation in the reticular dermis in porcine skin.

Effect of auditory, tactile, visual, and vestibular intervention on length of stay, alertness, and feeding progression in preterm infants.

This study determined whether an auditory, tactile, visual, and vestibular intervention (ATVV) reduced the length of hospitalization of 37 preterm infants by increasing the proportion of alert behavioral states, thereby improving their feeding progression. Participants comprised 12 infants born between 23 and 26 weeks' gestation with normal head ultrasounds and 25 CNS-injured infants born between 23 and 31 weeks' gestation. Infants were randomly assigned to the control group (11 males, five females) or study group (seven males, 14 females) at 32 weeks' postconceptional age. ATVV intervention was administered to the study group for 15 minutes, twice daily, 5 days per week, from 33 weeks of age until discharge. The study group demonstrated increased alertness during the first 5 minutes of intervention, which was significantly correlated to length of stay (p<0.05). The proportion of nippled (teat) intake increased significantly faster for the study group (p=0.0001). Infants in the study group were discharged at a mean of 36.54 weeks, 1.6 weeks earlier than control infants (p<0.05). ATVV intervention facilitated increased alertness, faster transition to complete nipple feeding, and decreased length of hospitalization.