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PubMed1992

The concept of dose intensification in the treatment of neoplastic disease.

This paper summarizes different theoretical and clinical approaches contributing to the concept of dose intensification. According to this concept, the amount of antineoplastic drug delivered per time predominantly determines the clinical outcome in patients with neoplastic disease. With the availability of recombinant haemopoietic growth factors haematotoxic side effects might be reduced, making this concept more feasible for clinical use. However, more prospective randomized studies, in which dose-intensity is the only treatment variable, are needed to prove that dose intensification will lead to higher survival rates.

Antineoplastic Agents↗
PubMed1990

Fetal damage due to maternal phenylketonuria: effects of dietary treatment and maternal phenylalanine concentrations around the time of conception (an interim report from the UK Phenylketonuria Register).

In 94 infants born to women with PKU, birth weight and head circumference were inversely and linearly related to the mothers' phenylalanine concentrations close to conception; with each 200 mumols/L rise in phenylalanine concentrations, birth weight fell by 98 g and head circumference by 0.46 cm. This relationship was highly significant and appeared to be the same whether or not the mother received a low phenylalanine diet. Even in the 28 infants whose mothers conceived on a strict low phenylalanine diet, birth weights and head circumferences, corrected for sex and gestation, were a little below the population norms (3421 g and 34.7 cm compared with 3600 g and 35.2 cm respectively) although the differences were not statistically significant. Optimal fetal growth occurred only in infants whose mothers had phenylalanine concentrations close to the normal range at conception. Dietary treatment started after conception did not appear to confer any benefit.

Adolescent↗
PubMed1996

A qualitative study to explore the concept of fatigue/tiredness in cancer patients and in healthy individuals.

Interest in fatigue research has grown since the finding that fatigue/tiredness is the most frequently reported symptom of cancer and its treatment. But even though several authors have tried to conceptualise fatigue, its mechanisms are still poorly understood. The aim of this study was twofold: (a) to explore fatigue in cancer patients inductively, and (b) to compare experiences of fatigue/tiredness of healthy individuals with those of cancer patients to identify cancer-specific fatigue/tiredness and related concepts. A qualitative research strategy was adopted using a grounded-theory approach. The prospective study took place in the oncology department of the Kantonsspital, St. Gallen, Switzerland, with samples of 20 cancer patients and 20 healthy individuals. Unstructured, tape-recorded interviews were conducted to collect data. The transcripts of the interviews were analysed using content analysis and constant comparison. Different themes emerged between the two groups although both fitted a classification system that categorised fatigue into physical, affective and cognitive expressions of fatigue/tiredness. Physical signs were more frequent than affective and cognitive signs in both groups. In the cancer patients, fatigue involved decreased physical performance, extreme, unusual tiredness, weakness and an unusual need for rest, which was distinctly different for healthy persons. Affective and cognitive distress was also more prominent in cancer patients. Interestingly, the concept of malaise was not identified by either sample and not understood as an expression of fatigue by this German-speaking population. Linguistic differences in the description of fatigue/tiredness between healthy and ill individuals revealed different perceptions of the phenomenon. A step-like theory, explaining the production of fatigue/tiredness was tentatively put forward involving nociception, perception and expression of tiredness. The emerging concepts break tiredness/fatigue into an expression of physical, affective and cognitive tiredness/fatigue. The experience is different between healthy individuals and cancer patients. Care must be taken when drawing generalised conclusions but the results of the study identify and clarify ideas that might form an important basis for further, controlled studies.

Adult↗
PubMed1991

Negative symptoms, defect state and Huber's basic symptoms: a comparison of the concepts.

Comparing Crow's schizophrenia model with the defect state and Huber's basic symptoms shows that this model is an oversimplification of the complex reality of schizophrenic outcomes. The concept of negative symptoms is undermined by several factors, such as differing definitions, other confounding cross-sectional variables (e.g., akinesia and depression), short follow-ups and lack of confirmation by factorial analysis. The longitudinal concept of a defect state, which has been used in long-term follow-up studies, includes enduring symptoms currently classified as positive and negative. Huber's conceptualization of basic symptoms describes prodromal and enduring residual symptoms of schizophrenia associated with structural brain abnormalities. The overlap and lack of equivalence of these concepts and the limited empirical evidence does not allow firm conclusions. New longitudinal studies using clinical, psychosocial, and neuropsychological measures are needed to understand the natural history and etiology of the defect state.

Cross-Sectional Studies↗
PubMed1996

The concept of uptake and retrograde transport of neurotrophic molecules during development: history and present status.

In the present review honoring Hans Thoenen's contributions to the concept of uptake and retrograde transport of trophic molecules, I have attempted to identify the major historical pathways that had to converge before this concept could be accepted as a fundamental principle in neurobiology. Some of the critical events in this history which are discussed here include: neuron-target interactions, bidirectional trophic signals, axoplasmic transport, receptor-mediated endocytosis, transneuronal trophic signals, the discovery of NGF, the retrograde transport of NGF, and the production of NGF by target tissues. Only when all of these diverse pieces of the puzzle were in place was the concept finally confirmed as being the mechanism that mediates the many phenomena attributed to the regulation and maintenance of neurons by their targets.

Animals↗
PubMed1991

Concept of Hokkaido University picture archiving communication system.

The basic concept of Hokkaido University picture archiving communication system (HU-PACS) for its design in hardware architecture and in its characteristic functions is reported. After almost 10 years, the concept was solidified as the opinion of most of the doctors of HU Hospital. Discussions with vendors were very helpful in providing technical or industrial expertise and equipment to effect this concept with the limited funds available.

Radiology Information Systems↗
PubMed2001

The different conceptions of catatonia: historical overview and critical discussion.

The present article outlines the different conception of catatonia from its initial description by Kahlbaum to current viewpoints. Originally considered to be an independent disease entity characterized by mental and motor abnormalities, catatonia was later viewed as a subtype of schizophrenia as it is the case in current classifications like ICD-10 and DSM-IV. Since catatonic symptoms were observable not only in schizophrenic psychoses, but also in affective, somatic or even psychogenic disorders, many researchers today consider catatonia as a nosologically unspecific syndrome. In the end, the traditional conceptions did not succeed in defining catatonia as a clinically homogeneous and valid diagnosis. An independent conception was elaborated by the Wernicke-Kleist-Leonhard school of psychiatry. Based on a precise differentiation of psychomotor disturbances, two essentially different forms of catatonic psychoses have been separated, systematic and periodic catatonias which differ in symptomatology, prognosis and treatment.

Catatonia↗
PubMed2004

Radiation therapy for nonmalignant diseases in Germany. Current concepts and future perspectives.

BACKGROUND: Radiotherapy (RT) of nonmalignant diseases has a long-standing tradition in Germany. Over the past decade significant theoretical and clinical progress has been made in this field to be internationally recognized as an important segment of clinical RT. This development is reflected in a national patterns-of-care study (PCS) conducted during the years 2001-2002. MATERIAL AND METHODS: In 2001 and 2002, a questionnaire was mailed to all RT facilities in Germany to assess equipment, patient accrual, RT indications, and treatment concepts. 146 of 180 institutions (81%) returned all requested data: 23 university hospitals (UNI), 95 community hospitals (COM), and 28 private institutions (PRIV). The specific diseases treated at each institution and the RT concepts were analyzed for frequencies and ratios between the different institution types. All data were compared to the first PCS in 1994-1996. RESULTS: In 137 institutions (94%) 415 megavoltage units (mean 1.7; range 1-4), and in 78 institutions (53%) 112 orthovoltage units (mean 1.1; range 0-2) were available. A mean of 37,410 patients were treated per year in all institutions: 503 (1.3%) for inflammatory disorders, 23,752 (63.5%) for degenerative, 1,252 (3.3%) for hypertrophic, and 11,051 (29.5%) for functional, other and unspecified disorders. In comparison to the first PCS there was a significant increase of patients per year (from 20,082 to 37,410; +86.3%) in most nonmalignant diseases during the past 7-8 years. Most disorders were treated in accordance with the national consensus guidelines: the prescribed dose concepts (single and total doses) varied much less during the period 2001-2002 in comparison with the previous PCS in 1994-1996. Only five institutions (3.4%) received recommendations to change single or total doses and/or treatment delivery. Univariate analysis detected significant institutional differences in the use of RT for various disorders. CONCLUSION: RT is increasingly accepted in Germany as a reasonable treatment option for many nonmalignant diseases. The long-term perspective and research plan will have to include various updates of PCS, re-writing of consensus guidelines, introduction of registries for rare nonmalignant disorders, and clinical controlled studies even for so-called established indications, as international acceptance is based on the criteria of evidence-based medicine.

Forecasting↗
PubMed2006

[Physical activity and health. Evidence for the health benefits of different physical activity promotion concepts].

Recent years have been marked by increased efforts of public health to pro mote physical activity. Concepts used for the promotion of physical activity range from the prescription of exercise to advice for "active living". The article compares existing evidence for the health benefits of the concepts of physical activity, health-enhancing physical activity, exercise and the German concept of "health sport". Furthermore, existing evidence for different promotion strategies for physical activity on the individual and population level are presented and discussed. Referring to the situation in Germany, the article intends to support current discussions regarding the development of health sport programs and initiatives to promote active living.

Exercise↗
PubMed1995

[The tuberculid concept from the current viewpoint].

The concept of tuberculid was introduced by Darier in 1896. In contrast to "true" cutaneous tuberculosis, properties of the tuberculids were explained by an hyperergic response to myobacteria or their fragments released from a different site of manifest or passed tuberculous infection. Key features include a strongly positive tuberculin skin test, evidence of concomitant manifest or past tuberculosis, and prompt response to antituberculous therapy. The inability to culture M. tuberculosis or to demonstrate it microscopically from lesional biopsies, together with reports on tuberculid-like eruptions after BCG vaccination, supports this concept. Clinical manifestations are lichen scrophulosorum, papulo-necrotic tuberculids and erythema induratum of Bazin. The existence of tuberculids has been questioned, however, because the clinical and histological appearances are not always specific. An increasing number of case reports on tuberculids, new immunological tests and molecular biology-based techniques for the detection of mycobacteria have shed new light on the tuberculid concept.

Diagnosis, Differential↗
PubMed2007

[Manipulator assisted endoscope guidance in functional endoscopic sinus surgery: proof of concept].

BACKGROUND: Functional endoscopic sinus surgery (FESS) is characterized by single-handed preparation and guidance of the endoscope by the nondominant hand. This results in an additional extension of operation time by up to 15% and ergonomic deficits. The aim of this study is the conception of an automated assistance system for FESS in view of the following questions: (1) Which degree of surgical automation is suitable for FESS? (2) Which design is suitable? (3) What are the properties of the technical system (planning, time, accuracy, precision) of the selected system? (4) Does the system offer potential for a clinical application? METHODS: In all 49 FESS were analyzed for surgical workflows. Measurement of the maximum forces within FESS was performed with 40 trials on an anatomical model. Three different mechanical systems were used in ten FESS and evaluated using the ICCAS Human-Machine Evaluation Scale. For realization of automated endoscope guidance an engine-driven and -braked manipulator (PA10-6c, Mitsubishi, Japan) was used. The technical parameters determined were expenditure of time for the preoperative planning of workspace, surgical accuracy and precision of the intraoperative endoscope positioning, maximal forces, and time. RESULTS: Concept-conditioned instrument changes amount to an average of 41.1 and 18.9% (5.21 min) time requirement for each FESS side. Maximum forces on the mucous membrane during a conventional FESS were measured at 9.8 N (5.9-9.8). Usability of the mechanical endoscope holder was estimated in 18 of 20 cases to be inferior to the standard procedure. The time needed for segmenting the intranasal workspace was 15.2 min (10.0-23.0). The maximum deviation of the automatically driven endoscope from a planned position amounted to 0.85 mm (manually 4.64 mm). The maximum force was measured with 1.1 N in the z direction (manually 9.8 N). Automated guidance of the endoscope to an intranasal position needed 7.25 s (6.4-7.9); manually 12.64 s (5.9-43.0). CONCLUSION: Guidance of the endoscope for FESS by an automated motor-driven system is possible. The conception which is based on workflow analysis favors a system with automatic definition of the workspace and a manual movement of the endoscope. The examined system offers a potential for clinical application. Definition of the automation level and development of a man-machine interface is more important than selection or reconstruction of a special manipulator for endoscope guidance in FESS from a surgical point of view.

Endoscopes↗
PubMed2006

Quantitative real-time RT-PCR data analysis: current concepts and the novel "gene expression's CT difference" formula.

For quantification of gene-specific mRNA, quantitative real-time RT-PCR has become one of the most frequently used methods over the last few years. This article focuses on the issue of real-time PCR data analysis and its mathematical background, offering a general concept for efficient, fast and precise data analysis superior to the commonly used comparative CT (DeltaDeltaCT) and the standard curve method, as it considers individual amplification efficiencies for every PCR. This concept is based on a novel formula for the calculation of relative gene expression ratios, termed GED (Gene Expression's CT Difference) formula. Prerequisites for this formula, such as real-time PCR kinetics, the concept of PCR efficiency and its determination, are discussed. Additionally, this article offers some technical considerations and information on statistical analysis of real-time PCR data.

Benzothiazoles↗
PubMed2003

[The concept of psychosis and psychotic qualities].

The term "psychosis," first used by Canstatt and then by von Feuchtersleben, originally meant "psychic neurosis," one of several forms of one disease group. The term was taken up by Flemming and introduced among other typical indications such as psychic disturbance, psychic disease, mind disease, and madness around 1875 in the German-speaking world."Psychosis" was understood from the beginning as a cerebral pathology which found its expression in psychic symptomatology. The broadest interpretation of the concept of psychosis prior to the turn of the nineteenth to the twentieth centuries has today been reduced to the modern differentiations of psychopathologies and neuroses. Since then, no consensus has been reached on the extent of the concept of psychosis.We have remained at the "persistent unclarity" described by H. Kindt. Contemporary diagnostic systems have done without the concept of psychosis. The indication "psychotic" which has taken its place and is based primarily on characteristically schizophrenic phenomena is also unclear. Independently of the unsolved problem of differentiation, there remains the question of psychotic qualities which are understandable on biologic and psychopathologic levels at the same time and which combine biologic, interpretative, and descriptive elements, uniting them in the field of biologic and clinical psychiatry.

Diagnosis, Differential↗
PubMed1997

[Acute cerebral infarct: physiopathology and modern therapeutic concepts].

This review focuses on the pathophysiological changes in acute cerebral ischemia, with special emphasis on disturbances of the cerebral blood flow (CBF) and the associated penumbra concept. Alternatively, the model of peri-infarct depolarization is demonstrated. Metabolic and molecular changes caused by cerebral ischemia and reperfusion are discussed, namely energy failure, release of glutamate with an excitatoric burst, calcium influx in neurons, generation of free radicals, activation of different proteases, disturbances of protein synthesis, induction of gene expression and apoptosis, loss of membrane integrity, edema formation and microvascular disturbances. In summary, the pathophysiological changes after focal cerebral ischemia and reperfusion are most adequately described by a network of interacting different mechanisms of tissue alterations. The simple concept of a cascade of ischemic effects which would be easy to block seems to be less applicable. A time window of approximately 6 h for the acute stroke therapy is postulated on the base of the above mentioned pathophysiological changes. The recently introduced treatment regimen with optimized basic treatment, recanalization using thrombolysis and neuroprotection by different agents is presented. Different modes of a possible intervention are discussed. Modern concepts of stroke therapy including stroke-unit care and thrombolysis with add-on neuroprotection seem to have potential for improving the outcome of acute stroke patients.

Acute Disease↗
PubMed2005

[New concept minimizes bleeding in radical retropubic prostatectomy].

BACKGROUND: Radical retropubic prostatectomy is an intervention known to be associated with severe bleeding. Even experienced surgeons report a blood transfusion rate of up to 20%. The perioperative concept for this intervention underwent various modifications in January 2001. This study describes the effect of these modifications on the blood loss in a retrospective analysis comparing approximately 100 operations by a single experienced surgeon before the change (group 1) with 100 operations thereafter (group 2). MATERIALS AND METHODS: The new perioperative concept comprised the following points: reducing the intravenously applied volume, employing a peridural catheter (PDC), and maintaining a 25-30 degrees Trendelenburg's position. The difference in pre- and postsurgical hemoglobin (Hb) was analyzed before (group 1) and after the intervention (group 2). If transfusions were performed, this value was corrected according to the following formula: 1 ml of erythrocyte concentrate increases the patient's Hb by 0.003 g/dl. RESULTS: Assessment was possible in 201 of 234 cases, 110 from the first and 91 from the second group. The mean transfusion-corrected Hb difference was 5.3 g/dl in group 1 (20% transfusion rate) and 3.52 g/dl in group 2 (1.09% transfusion rate); p>0.0001. The median intravenous volume applied was 5.960 ml in group 1 and 3.490 ml in group 2 (p>0.0001). The complication rate did not differ between groups. CONCLUSION: The new perioperative concept minimizes the intraoperative blood loss during radical open retropubic prostatectomy. Transfusions are only necessary in rare cases. The complication rate remains unaltered.

Blood Loss, Surgical↗
PubMed2005

[Current concepts of polytrauma management: from ATLS to "damage control"].

In recent years, the implementation of standardized protocols for polytrauma management has led to a significant improvement in trauma care as well as to a decrease in post-traumatic morbidity and mortality. As such, the "Advanced Trauma Life Support" (ATLS) protocol of the American College of Surgeons for the acute management of severely injured patients has been established as a gold standard in most European countries since the 1990s. Continuative concepts to the ATLS program include the "Definitive Surgical Trauma Care" (DSTC) algorithm and the concept of "damage control" surgery for polytraumatized patients with immediate life-threatening injuries. These phase-oriented therapeutic strategies appraise the injured patient of the whole extent of the sustained injuries and are in sharp contrast to previous modalities of "early total care" which advocate immediate definitive surgical intervention. The approach of "damage control" surgery takes into account the influence of systemic post-traumatic inflammatory and metabolic reactions of the organism and is aimed at reducing both the primary and the secondary, delayed, mortality in severely injured patients. The present paper provides an overview of the current state of management algorithms for polytrauma patients, with a focus on the standard concepts of ATLS and "damage control".

Adult↗
PubMed2005

The concept of "baby lung".

BACKGROUND: The "baby lung" concept originated as an offspring of computed tomography examinations which showed in most patients with acute lung injury/acute respiratory distress syndrome that the normally aerated tissue has the dimensions of the lung of a 5- to 6-year-old child (300-500 g aerated tissue). DISCUSSION: The respiratory system compliance is linearly related to the "baby lung" dimensions, suggesting that the acute respiratory distress syndrome lung is not "stiff" but instead small, with nearly normal intrinsic elasticity. Initially we taught that the "baby lung" is a distinct anatomical structure, in the nondependent lung regions. However, the density redistribution in prone position shows that the "baby lung" is a functional and not an anatomical concept. This provides a rational for "gentle lung treatment" and a background to explain concepts such as baro- and volutrauma. CONCLUSIONS: From a physiological perspective the "baby lung" helps to understand ventilator-induced lung injury. In this context, what appears dangerous is not the V(T)/kg ratio but instead the V(T)/"baby lung" ratio. The practical message is straightforward: the smaller the "baby lung," the greater is the potential for unsafe mechanical ventilation.

Extracorporeal Membrane Oxygenation↗
PubMed2005

Severe traumatic brain injury in pediatric patients: treatment and outcome using an intracranial pressure targeted therapy--the Lund concept.

OBJECTIVE: This study evaluated the outcome of treatment according to the Lund concept in children with severe traumatic brain injury and investigated whether the preset goals of the protocol were achieved. DESIGN AND SETTING: A two-center retrospective study in neurointensive care units at university hospitals. PATIENTS: Forty-one children with severe traumatic brain injury from blunt trauma and arriving at hospital within 24 h after injury. Median age was 8.8 years (range 3 months-14.2 years), Glasgow Coma Scale 7 (3-8), and Injury Severity Score 25 (16-75). All children had pathological findings on initial computed tomography. All developed intracranial hypertension, and survivors required intensive care longer than 72 h. INTERVENTIONS: Treatment according to the principles of the Lund concept. MEASUREMENTS AND RESULTS: Neurosurgery was required in 46% of the children. Survival rate was 93% and favorable outcome (Glasgow Outcome Score 4 or 5) was 80% at long-term follow-up (median 12 months postinjury, range 2.5-26). The preset physiological and biochemical goals were achieved in over 90% of observations. CONCLUSIONS: Treating pediatric patients with severe traumatic brain injury, according to the Lund concept, results in a favorable outcome when the protocol is followed.

Adolescent↗