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PubMed1985

Age-dependent effects of a pure tone trauma in the chick basilar papilla: evidence for a development of the tonotopic organization.

58 chicks or chick embryos were continuously exposed during 12 h on either embryonic day 18 or 20 or on post-hatching days 1, 10, 20 or 30 to 1.5 kHz pure tone at an intensity of 125 dB SPL. After a 20- or 30-day survival time, audiograms were recorded and then the basilar papillae were prepared for scanning electron microscopy. The frequency of maximum threshold elevation was seen at about 4 kHz when the chicks were exposed to the traumatic tone at embryonic day 18. It was shifted toward lower frequencies when the exposure was done at later stages. This shifting ended when the animals were exposed one day after hatching. After this stage, the maximum threshold elevation stabilized about one octave above the frequency of the traumatic tone. The position of maximum anatomical damage was located at 29.14% of the total length of the basilar papilla measured from the base when the exposure was done at embryonic day 20. It was shifted to 37% when the chicks were exposed one day after hatching or later. These results are in good agreement with recent hypotheses on development of the place principle. This development change seems to end at post-natal day 1 which also corresponds to the end of the anatomical and functional maturation of the basilar papilla.

Aging↗

PubMed2004

The effect of race/ethnicity on prostate cancer treatment outcome is conditional: a review of Wayne State University data.

PURPOSE: The mortality rate for prostate cancer in black American men (AAMs) is 2 times greater than that in other ethnic groups. However, there is considerable controversy as to whether race/ethnicity is an independent predictor of survival outcome. We present conditions in which race/ethnicity is and is not an independent predictor of survival outcomes. MATERIALS AND METHODS: We examined the conditions of age, stage and year of diagnosis, and the role of race/ethnicity on disease-free survival in men who underwent consecutive radical prostatectomy as monotherapy from 1990 to 1999. Data were collected from 229 AAMs and 562 white American men prospectively in the Karmanos Cancer Institute Prostate cancer data bases. RESULTS: When the majority of the cohort had pathologically organ confined disease, race/ethnicity was not an independent predictor of disease-free survival. When the majority of the cohort had a mean age of 70 years or greater, race/ethnicity was not an independent predictor. In studies done in the late 1990s, when the stage of radical prostatectomy cases had shifted toward pathologically organ confined disease as the dominant stage, race/ethnicity was not an independent predictor. However, if the cohort was diagnosed at younger age and/or with more advanced prostate cancer, race/ethnicity became an independent predictor. In the early 1990s there was pathologically advanced disease in the majority of our cohort. CONCLUSIONS: Race/ethnicity as an independent predictor of prostate cancer is conditional and dependent on age, stage and year of diagnosis. Year of diagnosis is associated with a stage shift to earlier staged prostate cancer from the early to late 1990s. In general, study cohorts are often subranges of the entire spectrum of prostate cancer that are limited by these factors, especially stage at diagnosis and treatment. If diagnosed and treated early enough, although there is evidence suggesting that AAMs have more aggressive disease biologically, the role of race as a factor in outcome is significantly decreased. The age factor is more complex and must be discussed in more detail.

Aged↗

PubMed1988

[Functional status of the cardiovascular system in Hodgkin's disease and the effect of radiotherapy].

The main indices of cardiohemodynamics, phase structure of the cardiac cycle and ECG were studied in 34 patients with Hodgkin's disease aged 16 to 43: before the initiation of therapy, after a course of radiotherapy and in long term after therapy. The patients were characterized by tachycardia increasing with a degree of a process, ECG signs of myocardiodystrophy, a tendency to the formation of the phase syndrome of hypodynamia, slight pulmonary hypertension, a decrease in AP and peripheral vascular resistance. After a course of radiotherapy according to a radical program functional indices of the cardiovascular system in most of the patients returned to normal. However signs of radiation pericarditis with a favorable clinical course developed in some patients. Long after therapy positive changes in the cardiovascular system were noted among patients with IIA stage, negative shifts were noted in patients with III-IV stage.

Adolescent↗

PubMed1996

Statistical features of hypnagogic EEG measured by a new scoring system.

The purpose of this study was to examine the durations of individual occurrences of each of nine hypnagogic electroencephalographic (EEG) stages and the interchange relationship among these stages. Most of the alpha patterns (stages 1, 2, and 3), ripples (stage 5), and spindles (stage 9) tended to last > 2 minutes. On the other hand, histograms of the durations of time in EEG flattening (stage 4) and vertex sharp wave (stages 6, 7, and 8) patterns had peaks that lasted < 30 seconds. Analysis of the sequences of EEG stage changes demonstrated that shifts to adjacent stages were most common for all stages. A smooth change in EEG stage occurred in the downward or upward direction in the hypnagogic state. This was especially true for the first five stages. EEG stages with vertex sharp waves (stages 6, 7, and 8), however, showed less-smooth changes, with approximately 20% of all changes involving a jump of more than one stage. These results show that the basic EEG activities in the sleep onset period are the alpha, theta, and sleep spindles activities, whereas the activities of vertex sharp waves seem to have a secondary or enhancing role, instead of independent characteristics.

Adult↗

PubMedDate not supplied

Stage T1c prostate cancer: a heterogeneous category with widely varying prognosis.

PURPOSE: Stage T1c prostate cancer is defined as nonpalpable disease diagnosed by needle biopsy. As more patients are being diagnosed early because of prostate-specific antigen (PSA) screening, the distribution of patients by stage has shifted dramatically. Although this group has traditionally been characterized as having early-stage disease and the best prognosis, on review of these patients, we instead found a very heterogeneous group with a wide spectrum of outcomes that depend on both patient (Gleason grade and pretreatment PSA) and treatment (dose) factors. METHODS AND MATERIALS: A retrospective analysis was performed on 353 patients with stage T1c prostate adenocarcinoma who were referred for radiation therapy from 1989-1999. All patients underwent central review of pathology. Patients were treated with external-beam radiation to doses of 60-78 Gy; 66% of the patients were treated with a dose of 70 Gy or higher. Clinical local recurrence, nodal recurrence, distant metastases, and PSA relapse were recorded. Kaplan-Meier methodology was used to determine survival. For evaluation of prognostic variables, the patients were grouped by Gleason score (2-6, 7, 8-10), pretreatment PSA level (< 10, 10-20, > 20 ng/mL), and dose delivered to the prostate (< or = 70 Gy, > 70 Gy). The log-rank test was used for univariate analysis, and Cox-regression was used for multivariate analysis. RESULTS: The median age was 69 years, and the median follow-up of surviving patients was 47 months. As a percentage of all patients with prostate cancer, stage T1c continually increased from 6% in 1989 to 47% in 1999. Of the 353 patients with T1c, 66% of the patients were in the Gleason group of 2-6, 27% had a Gleason score of 7, and 7% had a Gleason score of 8-10. Sixty-five percent of the group had a pretreatment PSA level of < 10 ng/ mL, 31% had a PSA level of 10-20 ng/mL, and 5% had a PSA level of > 20 ng/mL. For the entire group, the 8-year overall survival was 86%, and PSA relapse-free survival was 78%. By univariate analysis, Gleason score and pretreatment PSA were significant predictors of overall survival and PSA relapse-free survival. For PSA relapse-free survival, a radiation dose of more than 70 Gy was also a significant factor. By multivariate analysis, Gleason score, pretreatment PSA level, and radiation dose over 70 Gy were significant predictors of PSA relapse-free survival. As expected, patients with Gleason score < or = 6 and pretreatment PSA < 10 had an 8-year RFS of 90%, whereas patients with Gleason score of 8-9 and pretreatment PSA > 20 had a relapse-free survival of zero percent. DISCUSSION: Contrary to general assumption, stage T1c prostate cancer is composed of a very heterogeneous group of patients with varying outcomes. When treatment modalities and institutional data are evaluated, the spectrum of disease must be accounted for by additional prognostic factors and subset analysis. Improvement in prostate imaging and multiple core biopsies may be helpful in better defining the extent of disease in the individual patient.

Aged↗

PubMed1999

Reduction in interleukin-2-producing cells but not Th1 to Th2 shift in moderate and advanced stages of human immunodeficiency virus type-1-infection: direct analysis of intracellular cytokine concentrations in CD4+ CD8- T cells.

Previous studies have suggested that CD4+ T lymphocytes shift from the Th1 type to the Th2 type during disease progression in patients with the human immunodeficiency virus type-1 (HIV-1). In the present study, we used a modified method that allowed a direct measurement of intracellular cytokines in CD4+ CD8- T cells. A total of 48 HIV-1-infected (HIV+) and 16 HIV-1-uninfected (HIV-) individuals were studied. The percentages of CD4+ CD8- T cells producing interleukin-2 (IL-2), interferon-gamma (IFN-gamma), interleukin-4 (IL-4), or interleukin-5 (IL-5) in HIV+ and HIV- subjects were 23.6% versus 34.9% (P < 0.01), 13.7% versus 13.2%, 1.3% versus 1.0%, and 1. 2% versus 0.9%, respectively. The population of IL-2-producing cells decreased proportionately with reductions in CD4 counts (< 200/mm3, 200-500/mm3, and > 500/mm3 to 18.0%, 23.5%, and 30.5%, P < 0.05, respectively). There was an inverse correlation between the percentage of IL-2-producing cells and plasma viral load (r = - 0. 446, P < 0.05). However, the percentages of CD4+ CD8- T cells producing other cytokines were not different between HIV+ and HIV-. Our cross-sectional study demonstrated a decrease in IL-2-producing cells but not the Th1 to the Th2 shift in the CD4+ CD8- T cell population in the moderate and advanced stages of HIV-1-infection.

Adult↗

PubMed1989

[Status of immunologic reactivity and prospects of the implementation of occupational selection of workers at a microbiological plant].

The results of immunologic studies of different groups of workers engaged in the microbiologic synthesis production are presented. The study reveals a very important role of the immune system in the development of various forms of diseases. Differentiated shifts in various chains of cellular and humoral immunity have been identified in practically healthy people and in patients with occupational diseases both in acute condition and at the remittance stage. These shifts are specified by the form and stage of the disease, length of service at the given enterprise and individual immunity characteristics. By means of using immunograms it is possible to select patients with stable, adequate immune type enabling one to go on working at the industrial enterprise without any significant pathologic changes in the body.

Adult↗

PubMed1993

[Ultra-high dose streptokinase in treatment of arterial occlusions of leg arteries in advanced age].

In a retrospective study, the data of 218 patients (age 65-91) with obstructions of leg-arteries were evaluated, who underwent short-term ultrahigh fibrinolytic treatment. Some of the patients were also treated with percutaneous transluminal angioplasty after fibrinolysis. The overall patency-rate was 69 percent in the younger age group (65-74 years) and 46 percent in the group aged > or = 75. It could be shown, however, that the patency-rate was affected positively by concomitant factors (especially at least two patent calf arteries). These factors were less frequently found in the older age group, resulting in a lower patency-rate. Most likely the underlying reason is not age per se, because it could be shown, that the reason, which led to fibrinolytic treatment changed with age: In the younger age-group, Fontaine-stage II led to treatment in the vast majority of cases (71%). There was a shift to stage III (26%) and IV (27%) in the group > or = 75 years. This progression of artery disease usually leads to a reduced success rate of fibrinolytic treatment, because adverse concomitant factors prevail.

Aged↗

PubMed2005

A novel oligodendrocyte cell line OLP6 shows the successive stages of oligodendrocyte development: late progenitor, immature and mature stages.

The successive stages of development from oligodendrocyte progenitor to mature oligodendrocyte have been investigated in detail by using stage-specific antibodies. However, no cell lines are available that show stepwise differentiation from oligodendrocyte progenitors to mature oligodendrocytes. Here we show the establishment of an immortalized oligodendrocyte cell line, OLP6, from adult transgenic rats harboring the temperature-sensitive simian virus 40 large T-antigen gene. The OLP6 cells had a fibroblastic morphology and continuously proliferated at 33 degrees C. They displayed growth arrest and multipolar morphology when they were cultured at 39 degrees C. They express the oligodendrocytic markers O4, 2'-3'-cyclic-nucleotide 3'-phosphodiesterase, galactocerebroside and second endothelial differentiation gene receptor-2 at 39 degrees C. The OLP6 cells underwent apoptosis upon serum withdrawal at 39 degrees C. Lysophosphatidic acid inhibited this apoptosis and promoted the expression of myelin basic protein. These results demonstrate that the activation of endothelial differentiation gene receptor-2 exerts anti-apoptosis and myelinogenesis effects on the OLP6 cells. Taken together, the OLP6 cells in the late oligodendrocyte progenitor stage can progress to the immature oligodendrocyte stage by shifting culture temperature. Furthermore, lysophosphatidic acid promoted the maturation of OLP6 cells in the immature oligodendrocyte stage. Such OLP6 cells should provide a potent model system for studying the precise mechanism involved in stepwise differentiation of oligodendrocytes.

Animals↗

PubMed2001

Cost effectiveness of computer tailored and non-tailored smoking cessation letters in general practice: randomised controlled trial.

OBJECTIVES: To develop and evaluate, in a primary care setting, a computerised system for generating tailored letters about smoking cessation. DESIGN: Randomised controlled trial. SETTING: Six general practices in Aberdeen, Scotland. PARTICIPANTS: 2553 smokers aged 17 to 65. INTERVENTIONS: All participants received a questionnaire asking about their smoking. Participants subsequently received either a computer tailored or a non-tailored, standard letter on smoking cessation, or no letter. MAIN OUTCOME MEASURES: Prevalence of validated abstinence at six months; change in intention to stop smoking in the next six months. RESULTS: The validated cessation rate at six months was 3.5% (30/857) (95% confidence interval 2.3% to 4.7%) for the tailored letter group, 4.4% (37/846) (3.0% to 5.8%) for the non-tailored letter group, and 2.6% (22/850) (1.5% to 3.7%) for the control (no letter) group. After adjustment for significant covariates, the cessation rate was 66% greater (-4% to 186%; P=0.07) in the non-tailored letter group than that in the no letter group. Among participants who smoked <20 cigarettes per day, the cessation rate in the non-tailored letter group was 87% greater (0% to 246%; P=0.05) than that in the no letter group. Among heavy smokers who did not quit, a 76% higher rate of positive shift in "stage of change" (intention to quit within a particular period of time) was seen compared with those who received no letter (11% to 180%; P=0.02). The increase in cost for each additional quitter in the non-tailored letter group compared with the no letter group was pound 89. CONCLUSIONS: In a large general practice, a brief non-tailored letter effectively increased cessation rates among smokers. A tailored letter was not effective in increasing cessation rates but promoted shift in movement towards cessation ("stage of change") in heavy smokers. As a pragmatic tool to encourage cessation of smoking, a mass mailing of non-tailored letters from general practices is more cost effective than computer tailored letters or no letters.

Adolescent↗

PubMed1994

Diurnal blood pressure variation and hormonal correlates in fatal familial insomnia.

Fatal familial insomnia is a prion disease in which a selective thalamic degeneration leads to total sleep deprivation, hypertension, dysautonomia, adrenal overactivity, and impaired motor functions. With patients under continuous recumbency and polysomnographic control, we assessed the changes in the 24-hour patterns of blood pressure, heart rate, plasma catecholamines, corticotropin, and serum cortisol in three patients at different stages of the disease. Six healthy volunteers were used as control subjects. A dominant 24-hour component was detected at rhythm analysis of all variables, both in patients and control subjects. In the patients, the amplitudes gradually decreased as the disease progressed, leading to the obliteration of any significant dirunal variation only in the preterminal stage. A shift in phase corresponded to the loss of the nocturnal fall in blood pressure in an early stage of the disease, when nocturnal bradycardia was still preserved. Plasma cortisol was high and became increasingly elevated, whereas corticotropin remained within normal levels; abnormal nocturnal peaks appeared in their circadian patterns. The disrupted patterns of cortisol and blood pressure preceded the development of hypertension and severe dysautonomia, which in turn were paralleled by increasing catecholamine and heart rate levels. Our data demonstrate that in patients with fatal familial insomnia the changes detectable in the rhythmic component of diurnal blood pressure variability result in a pattern of secondary hypertension. Disturbances in thalamic, pituitary-adrenal, and autonomic functions seem to be involved in mediating these changes.

Adrenocorticotropic Hormone↗

PubMed1998

Microsatellite alterations at chromosomes 9p, 13q, and 17p in nonmuscle-invasive transitional cell carcinomas of the urinary bladder.

The clinical behavior of bladder cancer is difficult to predict and prognostic markers applicable to routinely processed tumor specimens clearly are needed. We screened 40 primary Ta and T1 bladder cancers for microsatellite alterations at 9p, 13q, and 17p with PCR, using nine polymorphic microsatellite markers. DNA was prepared after microdissection of paraffin-embedded transurethral resection specimens. PCR products were separated on sequencing gels, and allelic loss as well as band shifts was assessed by comparing alleles of control and tumor tissue. The results were correlated with grade, stage, and clinically documented tumor recurrence. Overall, allelic loss at 9p, 13q, and 17p was present in 35.1%, 25%, and 27.5% of cases, respectively. Whereas the frequency of allelic loss at 9p was nearly equally distributed throughout all tumor grades and stages, the occurrence of allelic loss at 13q and 17p correlated statistically significantly with higher grades and stage. Band shifts were observed in three cases. Of the 40 patients, 16 had tumor recurrence during a follow-up period of 3-49 months (median, 23 months). Kaplan-Meier analysis did not show any statistically significant correlation between allelic loss at either locus and tumor recurrence. The results confirm the role of alterations at 13q and 17p in the progression of bladder cancer. Allelic loss at 9p seems to be an early event in tumor development. However, the detection of alterations at the three chromosomal loci studied did not have any prognostic value regarding tumor recurrence in this group of patients.

Aged↗

PubMed1986

Epidemiological evaluation of early detection of cervical cancer in Slovenia till 1981.

Cervical cancer screening is performed in all Slovenia in connection with normal clinical practice since 1960. The results based on the data of Cancer Registry of Slovenia: trends in age, specific incidence rates and the distribution of intraepithelial and invasive cervical cancer incidence rates by communes revealed that cervical cancer screening is efficient in Slovenia; in two commune aggregates only and up to the age 40. A detailed analysis of cases of FIGO stage I into Ia and Ib stage demonstrated a shift of the peak of Ib stage to younger age in the two commune aggregates mentioned. The question is whether this shift of the peak of Ib stage could be an indicator of the unavoidable percentage of rapidly growing tumors in the population of SR Slovenia.

Adult↗

PubMed2026

Gut microbiota dynamics and metabolic pathways associated with bleomycin-induced pulmonary fibrosis progression.

BACKGROUND: Pulmonary fibrosis (PF) is a progressive respiratory disease characterized by epithelial injury, aberrant repair and excessive extracellular matrix deposition. Although the gut-lung axis is increasingly implicated in respiratory disorders, stage-resolved characterization of gut microbiota taxonomic and functional potential during PF development is limited. METHODS: We established a bleomycin-induced murine PF model and performed cross-sectional shotgun metagenomic sequencing of fecal samples from separate cohorts at three defined stages: baseline (control), day 7 (early fibrosis; M7), and day 14 (established fibrosis; M14). Microbial taxonomy, alpha/beta diversity, and predicted functional capacity were inferred using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Carbohydrate-Active enZymes (CAZy) annotations; associations were assessed using Procrustes and Spearman correlation analyses. RESULTS: Histopathology and immunohistochemistry confirmed progressive fibrogenesis with increased TGF-β1 and α-SMA expression. Compared with baseline, bleomycin-treated groups exhibited stage-specific shifts in gut microbial composition, including depletion of mucin-associated taxa (e.g., Prevotella, Akkermansia muciniphila) and expansion of Muribaculaceae- and Clostridiaceae-affiliated taxa. Alpha and beta diversity metrics differed across groups. KEGG/CAZy-based annotations revealed predicted, stage-dependent changes in microbial metabolic potential, including early reductions in pathways related to amino acid and glycan metabolism (M7) and later increases in predicted starch/sucrose catabolism, phosphotransferase system (PTS) representation, and secondary bile acid biosynthesis (M14). Correlation analyses linked compositional shifts to these predicted functional changes. CONCLUSION: In a stage-resolved, cross-sectional study, bleomycin-associated pulmonary fibrosis was accompanied by compositional and predicted functional alterations in the gut microbiota. These data identify candidate taxa and predicted pathways for follow-up mechanistic testing, but functional (metabolomic) and causality experiments are required to confirm whether and how microbial changes contribute to PF pathogenesis.

Animals↗

PubMed1985

Morphological changes in neutron irradiated red blood cells.

Living human red blood cells (erythrocytes) were irradiated with a beam of thermal neutrons having a thermal neutron flux of 9.4 X 10(9) neutrons/cm2 per sec corresponding to a dose rate of 5 Gray per hour. The neutron beam was obtained from the thermal neutron facility at the MIT Nuclear Reactor and contained some gamma-ray contamination which contributes approximately 8% of the dose effect. Approximately 92% of the dose effect is due to the neutron radiation. Populations of neutron irradiated red blood cells were examined under scanning electron microscopy to observe morphological changes due to the radiation dose. The thermal neutron doses ranged from zero for controls to 75 Gray, and cell populations were examined at various post-irradiation time periods of 10, 48, and 96 h. A four-stage discoid to spheroid shape transformation of the damaged red blood cells was characterized, and the time dependence of each transformation stage was determined for both unirradiated and irradiated cells. The radiation dose caused an initial dose-dependent shift from Stage 1 to Stage 2 with an associated increase in the transformation rate constants. The thermal neutron doses delivered are considered to be in the low dose range for radiation effects on red blood cells, yet the pronounced effects indicate a high relative biological effectiveness (RBE) for thermal neutrons.

Dose-Response Relationship, Radiation↗

PubMed1995

Electrophysiologic correlates of visuo-spatial attention shift.

We investigated neurophysiologic correlates of shifting visual attention across the visual field. Event-related potentials (ERPs) were recorded in 12 normal subjects during a visual discrimination task in which target stimuli were presented at a predictable or unpredictable location in the eccentric visual field. Subjects were obliged to shift their attention from the expected site to the unpredictable site immediately after the presentation of shifted stimuli in order to detect the change of stimulus attributes. Shifted stimuli modulated the N1 component (130-200 msec), producing a larger amplitude at the posterior temporal site contralateral to the stimulus field and a smaller amplitude over the ipsilateral hemisphere. Furthermore, shifted stimuli uniquely evoked a positive ERP component with a latency of 200-300 msec, which distributed broadly over the skull maximally at the frontal and central electrode sites. Both the negative and positive components changed in amplitude as a function of shift distance and direction. These results suggest that modulations of the negative and positive deflections reflect the shift of covert visuo-spatial attention and that right hemispheric dominance does not exist at least in the early stage of shifting spatial attention.

Adult↗

PubMed2006

The SPECTRUM population model of the impact of screening and treatment on U.S. breast cancer trends from 1975 to 2000: principles and practice of the model methods.

OBJECTIVE: This stochastic simulation model was developed to estimate the impact of screening and treatment diffusion on U.S. breast cancer mortality between 1975 and 2000. MODELING APPROACH: We use an event-driven continuous-time state transition model. Women who are destined to develop breast cancer may be screen detected, present with symptoms, or die of other causes before cancer is diagnosed. At presentation, the cancer has a stage assigned on the basis of mode of detection. Cancers are assumed to be estrogen receptor (ER) positive or negative. Data on screening and treatment diffusion are based on national datasets; other parameters are based on a synthesis of the evidence available in the literature. MODEL METHODS: The model is calibrated to predict incidence and stage distribution (in situ, local, regional, and distant). Other than screening or treatment, background events that affect mortality are not explicitly modeled but are captured in the deviation between model projections of mortality trends and actual trends. We assume that: 1) tumors progress more slowly in older age groups, 2) screen- and clinically detected disease have the same survival conditional on age and stage, 3) women do not die of breast cancer within the "lead time" period, 4) screening benefits are captured by shifts in stage at diagnosis, 4) tamoxifen benefits only ER-positive women, and 5) preclinical sojourn time and dwell times in each of the clinical stages are stochastically independent. MODEL RESULTS: Dissemination of screening and therapeutic advances had a substantial impact on mortality trends. We estimate that, by the year 2000, diffusion of screening lowered mortality by 12.4% and treatment improvements and dissemination lowered mortality by 14.6%. CONCLUSIONS: Models such as this one can be useful to translate clinical trial findings to general populations. This model can also be used inform policy debates about how to best achieve targeted reductions in breast cancer morbidity and mortality.

Adult↗

PubMed2004

What is the right thing at the right time? Interactions between stages and processes of change among smokers who make a quit attempt.

C. A. Perz, C. C. DiClemente, and J. P. Carbonari (1996) claim support for the transtheoretical model notion that success in smoking cessation involves doing the right thing at the right time: emphasising experiential change processes during the contemplation and preparation stages and shifting to behavioral process activities during action. A key methodological limitation of Perz et al. was their failure to control for stage of change, a measure that has been shown to be predictive of cessation. This study replicates the prospective findings of Perz et al. in a different data set, then controls for stage of change when it is predictive of cessation, and finds that the measures of "appropriate" change process use developed by Perz et al. no longer predict cessation. The authors conclude that stage of change, in particular the distinction between smoking and not smoking, is more important than change process use in predicting cessation outcomes.

Adolescent↗