Search PubMed⌕ Search

Biomedical subjects

F Meyer

Publications and source records attributed to F Meyer.

At least 91 records · Page 5Linked to original sources
PubMed1999

Evaporation of Accretion Disks around Black Holes: The Disk-Corona Transition and the Connection to the Advection-dominated Accretion Flow.

We apply the disk-corona evaporation model (Meyer & Meyer-Hofmeister) originally derived for dwarf novae to black hole systems. This model describes the transition of a thin cool outer disk to a hot coronal flow. The mass accretion rate determines the location of this transition. For a number of well-studied black hole binaries, we take the mass flow rates derived from a fit of the advection-dominated accretion flow (ADAF) model to the observed spectra (for a review, see Narayan, Mahadevan, & Quataert) and determine where the transition of accretion via a cool disk to a coronal flow/ADAF would be located for these rates. We compare this with the observed location of the inner disk edge, as estimated from the maximum velocity of the Halpha emission line. We find that the transition caused by evaporation agrees with this determination in stellar disks. We also show that the ADAF and the "thin outer disk + corona" are compatible in terms of the physics in the transition region.

Journal Article↗
PubMed1999

Screening for colorectal cancer with flexible sigmoidoscopy by nonphysician endoscopists.

PURPOSE: Screening with sigmoidoscopy reduces the risk of death from colorectal cancer. Only 30% of eligible patients have undergone sigmoidoscopy, in part because of a limited supply of endoscopists. We evaluated the performance and safety of screening sigmoidoscopic examinations by trained nonphysician endoscopists in comparison with board-certified gastroenterologists. SUBJECTS AND METHODS: Asymptomatic patients 50 years or older without evidence of fecal occult blood and no personal history or family history of a first-degree relative with colorectal cancer under age 55 years were offered sigmoidoscopy. All examinations were performed either by a gastroenterologist or a trained nonphysician endoscopist at a staff model health maintenance organization. Outcomes included the depth of examination, number and histology of polyps, and complications. RESULTS: Nonphysicians performed 2,323 sigmoidoscopic examinations, and physicians performed 1,378 examinations. The mean (+/-SD) depth of sigmoidoscopy examinations performed by nonphysicians was 52 +/- 10 cm compared with 55 +/- 9 cm (P <0.001) in physicians. Nonphysicians detected neoplastic polyps in a greater proportion of patients (7.8%) than physicians (5.8%), but this difference was not significant after adjusting for differences in the age, sex, and family history of the patients (P = 0.35). No major complications occurred. The cost per examination, including the nonphysician training cost, was lower for nonphysicians ($186 per examination) than for physicians ($283 per examination). CONCLUSIONS: Appropriately trained nonphysicians may be capable of performing safe and effective screening for colorectal cancer with flexible sigmoidoscopy. An increased use of nonphysicians to perform sigmoidoscopy may increase the availability and reduce the cost of the procedure.

Aged↗
PubMed1999

Deletions of the INK4A gene in superficial bladder tumors. Association with recurrence.

The INK4A and the INK4B genes map to chromosome 9p21, an area frequently deleted in bladder neoplasms. In addition to the p16 protein, the INK4A encodes for a second product, termed p19(ARF). We analyzed tissues from 121 patients with initial Ta and T1 tumors. Deletions of the INK4A gene were observed in 17 of 121 (14.1%) cases. Point mutations were identified in 2 of 64 (3.1%) tumors. The INK4A-exon 1beta and the INK4B gene were codeleted with INK4A in all of the homozygously deleted cases analyzed. The p16 promoter underwent de novo methylation in 7 of 47 (14.9%) evaluable cases. The p16-positive phenotype was observed in 18 of 56 (32%) evaluable cases. p16 negative phenotype correlated with deletion and methylation status. A statistically significant association between INK4A homozygous deletions and tumor size was observed (P = 0.003). Patients bearing tumors with INK4A homozygous deletions had a lower recurrence-free survival (P = 0.040) than those with wild type INK4A. In conclusion, deletions and methylation of the INK4A gene occur frequently in superficial bladder tumors. However, only those deletions that affect both the p16 and the p19(ARF), deregulating both the pRb and p53 pathways, correlated with clinicopathological parameters of worse prognosis.

Exons↗
PubMed1999

Neoadjuvant hormonal therapy before radical prostatectomy and risk of prostate specific antigen failure.

PURPOSE: To date there is little information on the long-term effect of neoadjuvant hormonal therapy on prostate cancer progression. We performed a prospective study to determine whether patients with prostate cancer receiving neoadjuvant hormonal therapy before radical prostatectomy (hormonal therapy group) have a lower risk of prostate specific antigen (PSA) failure than those treated with radical prostatectomy alone (prostatectomy group). We also evaluated whether type of neoadjuvant hormonal therapy and duration were associated with the risk of PSA failure. MATERIALS AND METHODS: We followed 680 men initially treated for prostate cancer with radical prostatectomy between January 1988 and December 1997 at our university hospital. Of the patients 292 received neoadjuvant hormonal therapy. Median followup was 38 months. Cox regression analysis was used to assess the association between neoadjuvant hormonal therapy and PSA failure (greater than 0.3 ng./ml.) controlling for age, clinical stage, grade, initial PSA and adjuvant therapies. RESULTS: Surgical margins were positive less often in the hormonal therapy (25%) than the prostatectomy (47%) group (p = 0.0001). PSA failure was observed in 163 patients and the 5-year failure rate was 33%. No difference in risk of PSA failure was observed overall between the hormonal therapy and prostatectomy groups (hazards ratio 0.94, 95% confidence interval 0.68 to 1.30). Treatments with antiandrogen alone for any duration, and those combining antiandrogen and luteinizing hormone-releasing hormone analogue for 3 months or less were not associated with improved survival. However, patients receiving combined therapy for more than 3 months had a significantly lower risk of PSA failure than those treated with radical prostatectomy alone (hazards ratio 0.52, 95% confidence interval 0.29 to 0.93). CONCLUSIONS: Prolonged neoadjuvant hormonal therapy combining antiandrogen and luteinizing hormone-releasing hormone analogue may improve disease-free survival after radical prostatectomy.

Adult↗
PubMed1999

Prognostic value of the proliferative index determined by Ki-67 immunostaining in superficial bladder tumors.

The biological behavior of urothelial carcinomas remains unpredictable. The objective of this study was to determine the prognostic value of Ki-67 index in superficial papillary bladder tumors and to correlate it with the S-phase fraction (SPF) measured by flow cytometry. Three hundred nineteen patients with newly diagnosed superficial (pTa, pT1) bladder tumors were included between September 1990 and April 1992. Patients with bladder carcinoma in situ alone were excluded. We observed 255 pTa tumors and 64 pT1 tumors, whereas 111 lesions were classified as grade G1 and 208 as grade G2-G3. Ki-67 immunostaining was performed on paraffin-embedded material using a 3-step immunoperoxidase procedure with the murine monoclonal antibody MiB1. The relation between Ki-67 expression and prognostic variables (stage, grade, tumor size, multifocality, age, and sex) was investigated by the chi-square test. Cox regression was used to describe the association between Ki-67 and tumor recurrence in 308 patients with follow-up while adjusting for potentially confounding prognostic variables. The frequency of high Ki-67 expression (> or =10%) increased with stage (P = .005) and grade (P = .001), but not with tumor size or multifocality. Two hundred one patients experienced tumor recurrence in a median follow-up of 68 months. Stage, grade, tumor size, and multifocality were all independent predictors of recurrence. Ki-67 index greater than 10% was found to be an independent predictor of tumor recurrence among patients with tumors larger than 3 cm in diameter (HR = 2.05, CI = 1.18-3.55), but not those with smaller size tumors. With regards to the DNA index, a significant but weak correlation was observed between Ki-67 expression and the SPF (Spearman's correlation coefficient = 0.23, P = .004). In addition, aneuploid tumors had significantly higher expression of Ki-67 (22.5%) than diploid tumors (10.1%) (P = .0006). Moreover, patients with DNA aneuploid bladder tumors were more likely to have more than 10% Ki-67-positive cells than those with diploid tumors. In patients with newly diagnosed pTa or pT1 bladder tumors, a Ki-67 index above 10% is an independent predictor of shorter time to recurrence only in those with tumors larger than 3 cm.

Aged↗
PubMed1999

[Application of the gel test using and anti-IgA antiglobulin for the immunologic diagnosis of autoimmune hemolytic anemia with a negative direct Coombs test].

Autoimmune hemolytic anemias (AIHA) are characterized by hyperhemolysis associated with the presence of the immunoglobulins IgG, IgM or IgA on the red cell membrane. These immunoglobulins react as auto-antibodies against the red cell auto-antigens of the patient. The diagnosis is supported by clinical and biological signs of hemolysis, and by the identification of the auto-antibodies using the direct antiglobulin test (DAT). Here we report 14 cases of patients who showed the clinical and biological profile of AIHA, but who gave a negative DAT. We therefore tried to determine the presence of IgA on the red cell membrane with a method more sensitive than the DAT: the gel test using anti-IgA. With such a gel test, we demonstrated that there were IgA auto-antibodies on the red cell membrane in the 14 cases, therefore confirming the diagnosis of AIHA. We discuss the interest of performing a gel test with anti-IgA in each case where AIHA is suspected, but in which a negative DAT has been observed.

Adolescent↗
PubMed1999

Morphometrical characterization of two glioma models in the brain of immunocompetent and immunodeficient rats.

Although several glioma models exist, systematic morphometrical studies on such experimental tumors are lacking. The purpose of this study was the quantitative assessment of how rat strains, cell lines, injection techniques and location affect tumors reproducibility and histopathological features. Glioma cells were implanted in 3 brain locations, with different injection techniques (free hand, stereotactic, water-tight device), variable volumes, cell concentrations and infusion rates. Tumors were developed from 2 rat glioma cell lines (9L and C6) in immunocompetent (Wistar and Fischer 344) and immunodeficient rats (New Zealand). Animals underwent daily neurological examination. At the scheduled time the tumors were macro and microscopically evaluated and a quantitative morphometrical analysis was performed. C6 gliomas appeared very infiltrative and irregularly shaped; 9L gliomas showed, by using the same injection technique, a grossly regular shape. Margins at the tumor-brain interface were macroscopically demarcated in the immunocompetent rats. In the nude rats, 9L tumors appeared microscopically more infiltrative, although regularly shaped, with a closer morphological resemblance to human gliomas. The implantation in the frontal area, anterior to the nucleus caudatus (3 mm anterior the coronal suture) gave reproducible tumor shape and size, no hydrocephalus and no early neurological deterioration. The use of a stereotactic technique or of a water-tight device, small volume (< 10 microl) of cell suspension, low infusion rate were useful to reduce morbidity and to improve data reproducibility. No difference in morbidity and mortality were observed in immunocompetent and immunodeficient rats. The 9L glioma model with stereotactic implantation constitutes a good option for reliable morphometrical evaluation of tumor growth. We propose a location for tumor implantation anterior to the nucleus caudatus. This produced the longest symptom-free survival.

Animals↗
PubMed1999

Dietary fat and prostate cancer survival.

OBJECTIVES: Relationships between dietary factors and the incidence of prostate cancer have emerged from epidemiologic and laboratory studies, but there are no published data on the relationship between diet and disease progression among prostate cancer patients. We studied the association between dietary fat intake and prostate cancer survival. METHODS: We prospectively followed 384 men diagnosed with prostate cancer between 1990 and 1992 in the Quebec City area. On average 3 months following diagnosis, trained nutritionists interviewed the men on their usual diet using a diet history questionnaire. Deaths during follow-up were documented through record linkage with the provincial mortality file and review of hospital records. Cox proportional hazard models were used to estimate the relative risk of dying from prostate cancer associated with terciles of fat intake, expressed as percent of dietary energy, while controlling for prognostic factors and total energy. RESULTS: The median duration of follow-up was 5.2 years. During the follow-up period 32 patients died of prostate cancer and 39 died of other causes. After controlling for grade, clinical stage, initial treatment, age and total energy intake, we found that saturated fat consumption was significantly associated with disease-specific survival (two-sided p-value = 0.008). Compared to men in the lower tercile of saturated fat, those in the upper tercile had three times the risk of dying from prostate cancer (relative risk = 3.1, 95% confidence interval: 1.3-7.7). CONCLUSIONS: Our findings suggest that saturated fat is related to disease-specific survival and that, if this relation is causal, a moderate reduction of its intake might reduce the risk of dying from prostate cancer.

Aged↗
PubMed1999

Ruptured infrarenal aortic aneurysm--a critical evaluation.

BACKGROUND: Objective evaluation of the management of patients with ruptured infrarenal aortic aneurysm in emergency situations has been described rarely. PATIENTS AND METHODS: Fifty-two consecutive patients with ruptured infrarenal aortic aneurysm (mean age, 70.3 years; range, 56-89 years; SD 7.8) were admitted between January 1993 and March 1998. Emergency protocols, final reports, and follow-up data were analyzed retrospectively. APACHE II scores at admission and fifth postoperative day were assessed. RESULTS: The time between the appearance of first symptoms and the referral of patients to the hospital was more than 5 hours in 37 patients (71%). Thirty-eight patients (71%) had signs of shock at time of admission. Ultrasound was performed in 81% of patients as the first diagnostic procedure. The most frequent site of aortic rupture was the left retroperitoneum (87%). Intraoperatively, acute left ventricular failure occurred in four patients, and cardiac arrest in two others. The postoperative course was complicated significantly in 34 patients. The overall mortality rate was 36.5% (n = 19). In 35 patients, APACHE II score was assessed, showing a probability of death of more than 40% in five patients and lower than 30% in 17 others. No patient showing probability of death of above 75% at the fifth postoperative day survived (n = 7). CONCLUSIONS: Ruptured aortic aneurysm demands surgical intervention. Clinical outcome is also influenced by preclinical and anesthetic management. The severity of disease as well as the patient's prognosis can be approximated using APACHE II score. Treatment results of heterogeneous patient groups can be compared.

APACHE↗
PubMed1999

Psychological stress and incidence of ischaemic heart disease.

BACKGROUND: We assessed the relationship between psychological stress and ischaemic heart disease (IHD) incidence in a population of 868 men over a 10-year follow-up period. METHODS: In 1981, 869 men aged 42-60, free from IHD and living around Quebec City completed a questionnaire assessing the presence of psychological stress in different areas of their life. They also underwent a medical examination and provided information on IHD risk factors. From 1981 to 1991, the incidence of IHD events was ascertained. The relationship between 13 stress dimensions and IHD incidence was investigated using Cox regression while controlling for important IHD risk factors. Cross-sectional analyses were also performed to investigate the relationship between stress dimensions and IHD risk factors. RESULTS: Between 1981 and 1991, 79 men (9%) experienced a first IHD event. The following risk factors were associated with the risk of IHD: age, (rate ratio (RR) = 1.93, 95% CI: 1.21-3.09), hypertension (RR = 1.90, 95% CI: 1.22-2.98), triglycerides (RR = 1.87, 95% CI: 1.19-2.95) and high density lipoprotein (HDL) cholesterol (RR = 1.64, 95% CI: 1.05-2.55). After controlling for risk factors, not one of the psychological stress dimensions significantly altered the risk of IHD. CONCLUSIONS: While confirming the influence of hypertension, age, triglycerides and HDL cholesterol on IHD incidence, this study suggests that there is no important connection between the explored stress dimensions and IHD incidence. It is unlikely that this lack of association is due to the stress questionnaire since the 13 stress dimensions were rigorously developed through independent evaluation of the questions by three specialists and many statistically significant relationships were observed between stress dimensions and IHD risk factors.

Adult↗
PubMed1999

Dietary fat and prostate cancer progression and survival.

BACKGROUND: The association between dietary factors and the occurrence of prostate cancer has been studied extensively, but there is, as yet, no published study on the relationship between diet and disease progression among prostate cancer patients. We studied the association between dietary fat intake and prostate cancer survival. METHODS: We prospectively followed 384 men diagnosed with prostate cancer between 1990 and 1992 in the Quebec City area who participated in a case-control study of diet in relation to prostate cancer occurrence. Trained nutritionists interviewed the men on their usual diet using a diet history questionnaire. Deaths in the follow-up were documented through record linkage with the provincial mortality file and review of hospital records. The cause of death was taken as written on the death certificate. Cox proportional hazards models were used to estimate the relative risk of dying from prostate cancer associated with terciles of fat intake, expressed as percent of dietary energy, while controlling for prognostic factors and total energy. RESULTS: The median duration of follow-up was 5.2 years. During the follow-up period, 32 patients died of prostate cancer and 39 died of other causes. The 5-year disease-specific survival was 91%. After controlling for grade, clinical stage, initial treatment, age and total energy intake, we found that saturated fat consumption was significantly associated with disease-specific survival (p = 0.008). Compared to men in the lower tercile of saturated fat, those in the upper tercile had three times the risk of dying from prostate cancer (hazards ratio 3.13, 95% confidence interval 1.28-7.67). CONCLUSION: Our findings suggest that, if saturated fat is causally related to disease-specific survival, a moderate reduction of its intake below 10% of energy should reduce the risk of dying from prostate cancer. This dietary goal is already recommended for health promotion and primary prevention of heart disease and cancer.

Aged↗
PubMed1999

Downward trend in prostate cancer mortality in Quebec and Canada.

PURPOSE: If new treatment strategies and screening for prostate cancer are effective they should reduce prostate cancer mortality. In this review we monitored prostate cancer mortality rates in Quebec and in Canada. MATERIALS AND METHODS: We obtained data on all deaths from prostate cancer between 1976 and 1997 in Quebec, and 1976 and 1996 in Canada. We calculated age standardized mortality rates and assessed changes with time. RESULTS: Prostate cancer mortality rates increased regularly until 1991 in Quebec and Canada. After 1991 the rates decreased moderately until 1995 and then more markedly in 1996. There was a further decline in 1997 in Quebec. Overall, age standardized prostate cancer mortality rates declined by 23% in Quebec between 1991 and 1997, and by 9.6% in Canada between 1991 and 1996. The mortality decline was observed for all age groups but was more pronounced among men younger than 75 years. CONCLUSIONS: Until 1995 the trends in prostate cancer mortality in Quebec and Canada were similar to those observed in the United States. Our data suggest that a sharper decline has occurred since 1995. It is of primary importance to identify the causes of the mortality decline. As prostate cancer mortality rates declined relatively early after the initiation of widespread screening with prostate specific antigen, it is unlikely that screening has as yet contributed in a major way to the decline. It is more likely that the mortality reduction is a consequence of better prostate cancer management or improved treatment modalities.

Age Distribution↗
PubMed1999

Heparin-induced vascular occlusion in vasculosurgical patients. An evaluation of the disease in 13 cases.

OBJECTIVE: To describe the diagnosis and treatment of adverse reaction to heparin (heparin-induced thrombocytopenia [HIT]) administered prophylactically for thrombosis and embolism. EXPERIMENTAL DESIGN: case series. SETTING: vascular surgical division in a University hospital. PATIENTS: thirteen patients treated for HIT type II between October 1994 and June 1997. Measures/Interventions: diagnosis of heparin-induced complications is based on exact medical history and regular measurement of platelet counts. Confirmation can be obtained with the aggregation test, serotonin-release test, heparininduced platelet release (HIPA) test, and platelet factor 4/heparin ELISA. Vasculosurgical reconstruction is usually required to eliminate vessel occlusion. RESULTS: In our series, HIT was confirmed by HIPA test (11 patients) and aggregation test (2 patients). All patients had positive cross reaction with low-molecular-weight heparin, and six had cross reaction with heparinoid danaproid sodium (Orgaran). Occlusions occurred between day 2 and 22 after the start or resumption of heparin administration (mean, 11 days). Anticoagulation treatment with hirudin or danaproid sodium was given to 5 patients, in conjunction with vasculosurgical reconstruction. Three of those patients died and the other two required amputation. CONCLUSIONS: Heparin-induced vascular occlusion is a rare but severe adverse effect of heparin treatment. When HIT is suspected, heparin administration must be stopped, with substitution of dextran and acetylsalicylic acid. Laboratory tests must be used for confirmation or exclusion. However, the diagnosis can be obscured by a normal platelet count due to pre-existing polycythemia and by false-negative test results. Surgery is usually warranted, depending on the degree and localization of ischemia.

Adult↗
PubMed1999

Aneurysm of the vertebral artery near the atlas arch.

In this case report, we describe an nontraumatic extracranial aneurysm of the vertebral artery at the V3 segment. Its etiology and pathogenesis could not be clarified completely. The walnut-sized aneurysm was treated surgically by proximal ligation. There were no postoperative complications.

Aneurysm↗
PubMed1999

Predictive value of cell cycle markers p53, MDM2, p21, and Ki-67 in superficial bladder tumor recurrence.

The aim of the study was to determine whether the expression of the cell cycle markers p53, MDM2, p21, and Ki-67 was predictive of superficial bladder cancer recurrence and to compare the relative predictive power for tumor recurrence of a cell cycle index based on the number of abnormally expressed cell cycle markers with a clinicopathological index based on primary clinical tumor characteristics. The expression of p53, MDM2, and p21 proteins and the value of the Ki-67 index were analyzed for 244 patients. One hundred ninety-four lesions were determined to be superficial papillary tumors (pTa), whereas 50 tumors invaded the lamina propria (pT1). Tumor grade was noted low (grade 1) in 83 cases and high (grades 2-3) in 161 cases. An avidin-biotin peroxidase method was performed using monoclonal antibodies against p53, MDM2, p21, and Ki-67 antigens after antigen retrieval treatment of formalin-fixed specimens. The cell cycle marker index was created using the number of abnormally expressed cell cycle markers according to the following cutoff points: p53 (>5%), MDM2 (>20%), p21 (<5%), and Ki-67 (>10%). The clinicopathological index was created using the following adverse tumor characteristics: grades G2-G3, stage pT1, multifocality, and diameter of tumors > 3 cm. Cox regression models were used to calculate the relative risks and their 95% confidence intervals associated with disease recurrence for the clinicopathological index and the cell cycle marker index. The chi2 test was performed to describe the correlation between the Ki-67 index and p53, MDM2, and p21 protein expression. Kaplan-Meier survival curves were generated to demonstrate the disease-free survival according to these two prognostic indexes. The clinicopathological index was a strong, independent predictor of disease recurrence where tumors with three or four adverse tumor characteristics at initial resection had over four times the risk of recurrence than tumors with no risk factors (P for trend = 0.0001). A strong correlation was observed between the Ki-67 index >10% and both MDM2 and p21 proteins. MDM2 was overexpressed in 106 tumors (43%), and p53 was overexpressed in 47 (19%); Ki-67 was >10% in 171 cases (70%). Thirty-nine tumors (16%) were p21 negative. The risk of recurrence increased slightly with the number of abnormally expressed cell cycle markers, but when the clinicopathological index was taken into account in multivariate analysis, the cell cycle marker index was not predictive of disease recurrence (P for trend = 0.72). The cell cycle markers studied provided no added prognostic information on disease recurrence after initial resection of papillary superficial tumors when the clinicopathological parameters were taken into account.

Aged↗
PubMed1998

Analysis and simulation of complex interactions during dynamic microfiltration of Escherichia coli suspensions.

Microfiltration is an important unit operation in downstream processing. However, due to the influence of membrane fouling, prediction of the filtration performance for biological suspensions is difficult. This paper describes a modeling approach that allows a comprehensive description of filtration performance. On the basis of experimental data and linguistic information, a specific artificial neural network was developed that predicts the process behavior within a certain range of parameters. This approach allows us to analyze influences of fermentation on filtration. By using extensive simulations, the interactions of 17 parameters were examined and the fouling causes determined. The model was developed for cell harvesting of Escherichia coli through a shear-enhanced module. The method can be applied to any cross-flow filtration process.

Bacteriological Techniques↗
PubMed1998

[Determining diagnosis and therapy control of hypertension by time-limited loan of blood pressure monitors to patients. A report of experiences with acceptance and practical applications of the procedure in general practice].

Data from an investigation on acceptance and practicability of a temporary self assessment of blood pressure values including 181 patients of a rural practise are presented. Cooperation of the total collective was surprisingly good although particularly those patients with most risk factors revealed deficits in fulfilling the preconceived goals. Compared to 24 hour blood pressure monitoring total drop out rate in the self assessment group was lower (6.6%) although the requirement for involvement and cooperation was increased in this group. On an average about 39 blood pressure measurements have been performed by each patient. In the protocol six measurements per day over a period of 8 days were scheduled, amounting to a total number of single data recorded by experience of other authors to be sufficient for a valid assessment of the real blood pressure situation of each patient. In view of this proof of a satisfying cooperation and the relatively low costs of this method we believe that, according to our personal experience, this method (temporary blood pressure monitoring with rented blood pressure apparatus) may be recommended to every family doctor interested in adequate blood pressure diagnosis. As the investigation demonstrated the efforts caused by this method are low and do not interfere with usual activities in the office of a family doctor. On the other hand the pedagogic effect on the patient may not be underestimated.

Adolescent↗