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PubMed1997

The biopharmaceutic drug classification and drugs administered in extended release (ER) formulations.

A biopharmaceutic drug classification scheme for correlating the in-vitro drug product dissolution and in-vivo bioavailability for IR products was proposed by Amidon et al (1995). The classification arose from drug dissolution and absorption models which identified the key parameters controlling drug absorption as the dimensionless numbers; the Absorption number (A(n)), the Dissolution number (Dn) and the Dose number (D(o)). This led to a biopharmaceutic classification of drugs into four groups, the establishment of a basis for determining the conditions under which in-vitro-in-vivo (IVIV) correlation's are expected and the use of the classification to set drug bioavailability standards for IR products. These developments raise the issue of whether the biopharmaceutic classification has relevance to ER products. In contrast to IR products, drugs selected for ER products should have good gastrointestinal (GI) permeability and an extended site of absorption. However their permeability(Papp) may change depending on the site. Solubility(Cs), effective fluid volume and hence D(o) may also vary with site. Of particular relevance to both permeability and solubility is the degree of ionization of the drug. Residence time at each site, pH changes and the potential for drug degradation at different sites, the latter resulting in a restricted absorption window, will influence the time frame over which an IVIV relationship is possible. Of the drugs available in ER dosage forms approximately 63% are bases, 15% acids and the remainder either unionizable or small inorganic ions. Acidic drugs will tend to have lower solubility's high up in the gastrointestinal tract (GIT), with solubility increasing down the GIT. In contrast with increased ionization permeability should fall. Thus with acids, as the dosage form moves to a more alkaline environment down the GIT, absorption may change from dissolution control to membrane control depending on the pK.a of the drug. In contrast bases will loose solubility with transit down the GIT, but become more permeable; absorption becoming more dissolution/release controlled or in extreme cases solubility controlled in the latter stages of the absorption phase. In the light of the above considerations a modified biopharmaceutic classification is proposed for ER products.

Biological Availability↗

PubMedDate not supplied

pTNM and residual tumor classifications: problems of assessment and prognostic significance.

The anatomic extent of tumor (TNM, pTNM) and, in case of treatment, the residual tumor status following treatment (residual tumor, or R classification) are the strongest predictors for outcome of patients with gastrointestinal cancer. The results of the pTNM and the R classifications depend on the methods used. In particular, the pN classification correlates with the number of nodes examined. The findings of micrometastases or isolated tumor cells in bone marrow should be indicated, and such cases must be analyzed separately from other metastatic cases. The same applies to patients with positive cytology in ascites fluid or peritoneal washings without gross involvement of the peritoneum. For the R classification the additional descriptors (conv), for conventional methods used, and (soph), for sophisticated, are recommended to indicate the methods used for classification. In general, long-term survival can be expected only after R0 resection (resection without residual tumor). The observed 5-year survival after R0 resection is 15% to 40% for esophageal carcinoma, 40% to 75% for gastric carcinoma, and 55% to 60% for colorectal carcinoma; the respective figures for R1 and R2 resections are only about 5% each. In R1 and R2 cases prognosis is determined primarily by the absence or presence of distant metastases, and pT and pN are of minor significance. After R0 resection there is a wide spectrum of prognoses. Careful pTNM classification allows a good estimation of the prognosis and can be considered the gold standard for any analysis of treatment results.

Gastrointestinal Neoplasms↗

PubMed1994

A comprehensive classification of thoracic and lumbar injuries.

In view of the current level of knowledge and the numerous treatment possibilities, none of the existing classification systems of thoracic and lumbar injuries is completely satisfactory. As a result of more than a decade of consideration of the subject matter and a review of 1445 consecutive thoracolumbar injuries, a comprehensive classification of thoracic and lumbar injuries is proposed. The classification is primarily based on pathomorphological criteria. Categories are established according to the main mechanism of injury, pathomorphological uniformity, and in consideration of prognostic aspects regarding healing potential. The classification reflects a progressive scale of morphological damage by which the degree of instability is determined. The severity of the injury in terms of instability is expressed by its ranking within the classification system. A simple grid, the 3-3-3 scheme of the AO fracture classification, was used in grouping the injuries. This grid consists of three types: A, B, and C. Every type has three groups, each of which contains three subgroups with specifications. The types have a fundamental injury pattern which is determined by the three most important mechanisms acting on the spine: compression, distraction, and axial torque. Type A (vertebral body compression) focuses on injury patterns of the vertebral body. Type B injuries (anterior and posterior element injuries with distraction) are characterized by transverse disruption either anteriorly or posteriorly. Type C lesions (anterior and posterior element injuries with rotation) describe injury patterns resulting from axial torque. The latter are most often superimposed on either type A or type B lesions. Morphological criteria are predominantly used for further subdivision of the injuries. Severity progresses from type A through type C as well as within the types, groups, and further subdivisions. The 1445 cases were analyzed with regard to the level of the main injury, the frequency of types and groups, and the incidence of neurological deficit. Most injuries occurred around the thoracolumbar junction. The upper and lower end of the thoracolumbar spine and the T10 level were most infrequently injured. Type A fractures were found in 66.1%, type B in 14.5%, and type C in 19.4% of the cases. Stable type A1 fractures accounted for 34.7% of the total. Some injury patterns are typical for certain sections of the thoracolumbar spine and others for age groups. The neurological deficit, ranging from complete paraplegia to a single root lesion, was evaluated in 1212 cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Humans↗

PubMed1992

Clinical classification of perianal Crohn's disease.

Assessment of the efficacy of therapeutic approaches to anal lesions of Crohn's disease is frustrated by the lack of precise definition of its various manifestations. A classification that is clinical and based on anatomic and pathologic aspects is presented; it has been derived from a 20-year prospective study of anal Crohn's disease in Cardiff. Conceptually, the classification is analogous to the TNM system for cancer. The main classification (U.F.S.) defines the presence of Ulceration, Fistula/abscess, and Stricture, qualified by numeric values reflecting severity (0 = not present, 1 = limited clinical impact, and 2 = severe). A subsidiary classification (A.P.D.) defines Associated conditions, Proximal intestinal involvement, and Disease activity. In addition, the classification may be used in a detailed form for research or comparative purposes or in a simple form defining only the dominant lesions for routine clinical use. General use of the classification would make it possible to compare in detail incidence, management, and results of treatment in different centers.

Abscess↗

PubMed2000

Selecting relevant electrode positions for classification tasks based on the electro-encephalogram.

The aim is to describe a general approach to determining important electrode positions when measured electro-encephalogram signals are used for classification. The approach is exemplified in the frame of the brain-computer interface, which crucially depends on the classification of different brain states. To classify two brain states, e.g. planning of movement of right and left index fingers, three different approaches are compared: classification using a physiologically motivated set of four electrodes, a set determined by principal component analysis and electrodes determined by spatial pattern analysis. Spatial pattern analysis enhances the classification rate significantly from 61.3 +/- 1.8% (with four electrodes) to 71.8 +/- 1.4%, whereas the classification rate using principal component analysis is significantly lower (65.2 +/- 1.4%). Most of the 61 electrodes used have no influence on the classification rate, so that, in future experiments, the setup can be simplified drastically to six to eight electrodes without loss of information.

Electrodes↗

PubMed2005

Signal-dependent wavelets for electromyogram classification.

In the study, an efficient method to perform supervised classification of surface electromyogram (EMG) signals is proposed. The method is based on the choice of a relevant representation space and its optimisation with respect to a training set. As EMG signals are the summation of compact-support waveforms (the motor unit action potentials), a natural tool for their representation is the discrete dyadic wavelet transform. The feature space was thus built from the marginals of a discrete wavelet decomposition. The mother wavelet was designed to minimise the probability of classification error estimated on the learning set (supervised classification). As a representative example, the method was applied to simulate surface EMG signals generated by motor units with different degrees of short-term synchronisation. The proposed approach was able to distinguish surface EMG signals with degrees of synchronisation that differed by 10%, with a misclassification rate of 8%. The performance of a spectral-based classification (error rate approximately 33%) and of the classification with Daubechies wavelet (21%) was significantly poorer than with the proposed wavelet optimisation. The method can be used for a number of different application fields of surface EMG classification, as the feature space is adapted to the characteristics of the signal that discriminate between classes.

Action Potentials↗

PubMed1999

Evaluation of Karhunen-Loève expansion for feature selection in computer-assisted classification of bioprosthetic heart-valve status.

This paper analyses the performance of four different feature-selection approaches of the Karhunen-Loève expansion (KLE) method to select the most discriminant set of features for computer-assisted classification of bioprosthetic heart-valve status. First, an evaluation test reducing the number of initial features while maintaining the performance of the original classifier is developed. Secondly, the effectiveness of the classification in a simulated practical situation where a new sample has to be classified is estimated with a validation test. Results from both tests applied to a reference database show that the most efficient feature selection and classification (> or = 97% of correct classifications (CCs)) are performed by the Kittler and Young approach. For the clinical databases, this approach provides poor classification results for simulated 'new samples' (between 50 and 69% of CCs). For both the evaluation and the validation tests, only the Heydorn and Tou approach provides classification results comparable with those of the original classifier (a difference always < or = 7%). However, the degree of feature reduction is particularly variable. The study demonstrates that the KLE feature-selection approaches are highly population-dependent. It also shows that the validation method proposed is advantageous in clinical applications where the data collection is difficult to perform.

Bioprosthesis↗

PubMed2002

Oncological significance of WHO histological thymoma classification. A clinical study based on 286 patients.

OBJECTIVES: The clinical significance of thymoma histology remains controversial because of the numerous histological classifications of thymic epithelial tumors. Universal classification of such tumors was achieved by the World Health Organization (WHO) in 1999. We studied the prognostic significance of this classification. METHODS: We studied clinical features and postoperative survival in cases of thymoma, but not thymic carcinoma, based on WHO histological classification in 286 patients undergoing surgery between 1958 and 2001. RESULTS: Tumors were 19 type A, 79 type AB, 59 type B1, 102 type B2, and 27 type B3. The proportion of invasive tumors increased by type--from A to AB, B1, B2, and B3. The great vessels were involved more frequently in type B2 and B3 tumors than in type A, AB, and B1 tumors. The 20-year survival was 100% in type A, 87% in type AB, 91% in type B1, 65% in type B2, and 38% in type B3 tumors. Multivariate analysis showed Masaoka staging and WHO histological classification to be significant independent prognostic factors, while age, gender, myasthenia gravis association, resection completeness and great vessel involvement were not. In stage III patients, 13 of 45 patients with type B2 and B3 tumor died of their tumors, while no tumor deaths occurred in 11 patients with type A, AB, and B1 tumors. CONCLUSION: WHO histological classification realistically reflects the oncological behavior of thymoma.

Adolescent↗

PubMed1999

Classification of lymph node metastases from carcinoma of the stomach: comparison of the old (1987) and new (1997) TNM systems.

The pN classification of gastric cancer is currently based on the distance of metastatic nodes from the primary tumor (TNM-1987). The UICC (Union Internationale Contre le Cancer) has recently proposed a new classification system based on the number of the involved nodes (TNM-1997). The present prospective study is aimed at verifying whether the two classifications (1) assign approximately a similar rank to individual patients and (2) give comparable prognostic information. The Cox regression model was used to evaluate the prognostic significance of either the distance or the number of positive nodes, controlling for sex, age, site, histology and depth of tumor invasion, in a group of 175 patients who underwent curative surgery for gastric cancer from March 1988 to October 1997. Among the patients classified as N1 and N2 according to TNM-1987, 81.8% (36/44) and 35.8% (19/53), respectively, were coded as N1 and N2 by the new classification. The survival probabilities of N1 and N2 categories were similar in both classifications. The N2 category of TNM-1987 comprised also 10 cases with >15 positive nodes (N3 category of TNM-1997), who presented a large excess mortality (RR = 35.14 with respect to N0). When the site and number of positive nodes are combined in a new variable, both appear to be important from a prognostic point of view. Both anatomic location and number of nodes with metastasis are important predictors of survival in gastric cancer patients. Caution should be used when replacing the old classification with the new one, as they group patients in a different way.

Age Factors↗

PubMed1997

[Injury classification and surgical approach in hip dislocations and fractures].

During the last few decades, traumatic injuries of the hip joint have significantly increased in number, and traffic accidents have also increased. Depending on the speed, direction of the forces and the position of the femur at the moment of impact, different patterns of injury occur. Basically, they are classified as hip dislocations, dislocation fractures and acetabular fractures. These injuries have in common a high rate of concomitant lesions. Several classification systems have been developed for these injuries. Commonly, Stewart and Milford's or Levin's classification is used for dislocations and dislocation fractures. For acetabular fractures, Judet and Letournel's classification and its newer version developed by Helfet (AO classification) are generally accepted. Fractures of the femoral head, though included in these classifications, are typically described by separate classifications like the one presented in 1957 by Pipkin. The multitude of injuries occurring in the hip joint requires vast knowledge of various operative approaches. No single approach exists that would permit the treatment of all injuries in an ideal fashion. Approaches are either considered limited (Kocher-Langenbeck, ilioinguinal iliofemoral) when they permit access only to a restricted segment of the joint, or extended (extended iliofemoral, Maryland, Ruedi) when they allow all-round visualization of the hip joint. The choice of the best approach for an individual patient depends on the type of injury and also on patient variables like age, preexisting disease, and concomitant injuries. The decision is further influenced by the timing of surgery, the kind of fracture stabilization intended and by complications typically seen with certain approaches. The indication for extended procedures is only seen in patients with complex injury patterns involving both the anterior and the posterior column or in delayed cases undergoing surgery more than 3 weeks after trauma. Extended approaches permit excellent visualization of the fracture, but the extent of the soft tissue trauma is reflected in a high rate of postoperative complications. After a phase in which extended procedures were favored, recently a trend towards more limited approaches can be recognized because of their lower complication rate. This is facilitated by modern fracture-reduction methods using indirect techniques.

Acetabulum↗

PubMed2000

Computerized classification of corpus cavernosum electromyogram signals by the use of discriminant analysis and artificial neural networks to support diagnosis of erectile dysfunction.

Corpus cavernosum electromyogram (CC-EMG) provides diagnostic information on cavernous autonomic innervation and a measure of the degree to which the cavernous smooth muscle cells are intact. The complicated CC-EMG is evaluated and used in the diagnosis of patients suffering from erectile dysfunction. The evaluation procedure has been simplified by applying digital signal processing techniques. Since mathematically-based interpretations require quantitative data, spectral analysis was performed. The derived biosignals were analyzed by fast Fourier transform (FFT). Besides various other spectral parameters, specific frequency bands were determined in the power spectrum using factor analysis. The parameters were used for the computerized classification of normal and pathological CC-EMG data and the classification was performed using two independent methods: discriminant analysis (DA) and artificial neural networks (ANN). A medical expert analyzed a total of 200 CC-EMG recordings from patients with and without erectile dysfunction and separated these into normal (136) and pathological (64) cases. Although each independent method had already resulted in a relatively high number of correct classifications, the classification success rate could be slightly improved by using a combination of both classification methods. A total of 72.79% and 77.94% were successfully classified using DA and ANN, respectively. The combination of both methods increased the classification success to 80.15%. The results of this study enabled impartial evaluation of the CC-EMG signals for clinical diagnostic purposes of erectile dysfunction. This method provided an objective and easy way to analyze the CC-EMG. Furthermore, this results in patient diagnosis becoming an easier task for less experienced doctors, since little knowledge of the raw signal is needed.

Algorithms↗

PubMed2005

Inter-observer reliability in the assessment of heterotopic ossification: proposal of a combined classification.

We applied four published classifications for assessment of heterotopic ossification after total hip arthroplasty (Arcq, Brooker, DeLee and Della Valle [1, 2, 5, 6]. The average incidence of heterotopic ossification varied from 19.8% to 27.7%. The inter-observer reliability of the various classifications was determined by Cohen's Kappa statistic. Kappa values ranged from 0.897 for Arcq's to 0.814 for Brooker's classification. In order to increase the reliability and consistency, we propose a new classification system combining Brooker's and Della Valle's classifications. This new classification preserves the high reliability of Della Valle's system and is comparable to previous publications since it includes Brooker's criteria.

Aged↗

PubMedDate not supplied

Etiology, definition, and classification of gluteal ptosis.

BACKGROUND: Despite the growing interest in aesthetic surgery of the buttocks and posterior body contouring, there is no clear definition of gluteal ptosis nor any classification enabling standardized diagnoses and treatments of the problem. The author proposes a classification to differentiate between pseudo-ptosis, PRE-ptosis, and true ptosis. The classification includes five degrees of severity and two factors (the length of the lower gluteal crease and the measurement, in centimeters, of posterior gluteal tissue exceeding the crease at a sagittal line that passes through the middle of the thigh, seen from behind, which the author proposes to call the "M" line). The article exposes the anatomy involved in ptosis and presents a theory about the mechanism through which gluteal ptosis is formed. METHODS: During a 1-year period, 87 patients, eligible for different types of body aesthetic surgery, were assessed according to the proposed classification. Their ages ranged from 16 to 64 years, and their weight ranged from 43 to 82 kg. Body mass index was used to classify overweight patients. Weight loss was considered in 10% increments. RESULTS: The authors were able to classify all the patients according to the proposed classification. Weight, age, and weight loss were directly related to the severity of the ptosis. CONCLUSIONS: The proposed classification is easy to apply and has the ability to standardize diagnoses and treatments for gluteal ptosis. This study also shows that weight gain, aging, and weight loss are etiologic agents of ptosis.

Adolescent↗

PubMedDate not supplied

A new classification of male pattern baldness and a clinical study of the anterior hairline.

Male pattern baldness is the most common type of baldness occurring after the age of puberty. Various surgical techniques for hair reconstruction have been introduced. Since the Norwood classification method is too detailed and complicated to be used for various surgical operations, there is a strong need for a simpler classification. Selection of the shape and height of the frontal and temporal hairlines is important in hair restoration surgery. But due to lack of standard measures, there have been difficulties in performing surgical operations for male pattern baldness. We therefore studied the prevalence of male pattern baldness in 1731 Korean men according to age and types, based on the new classification method, between September 1995 and February 1996. At the same time, we also measured the average heights of the frontal and temporal hairlines and identified the morphology and the incidence of various types of anterior hairlines in 108 normal male adults. There are six types of male pattern baldness according to the new classification method. One peculiar type could not be classified by the Norwood classification method. The six types are designated types M, C, O, U, MO, and CO. In the morphological classification of the anterior hairline, the linear type was most common (70.37%). The heights of the frontal and temporal hairlines were 6.53 cm for the median line, 5.9 cm (left side) and 5.95 cm (right side) for the paramedian line, 8.49 cm (left and right side) for the temporal recession line, and 6.61 cm (left side) and 6.62 cm (right side) for the temporal hairline. The authors present the research outcomes as baselines that can be used for hair restoration surgery and further study of male pattern baldness.

Adult↗

PubMed2001

Differences between biopsy- or specimen-related Laurén and World Health Organization classification in gastric cancer.

The extent of stomach resection in gastric cancer depends on tumor size, tumor location, depth of invasion, and the histological allocation to intestinal or diffuse type according to Laurén. As the latter is based on preoperative findings we performed a retrospective histomorphological study to quantify the differences between biopsy-related and surgical specimen-related Laurén classification. Additionally the World Health Organization (WHO) classification of preoperative endoscopic biopsies and surgical specimens were compared. Preoperative biopsies and resected tumor specimens from 100 patients with primary gastric carcinoma were retrospectively classified according toLaurén and WHO. The reclassification was independently performed by three pathologists who were not aware of the previous diagnoses. In 74% the Laurén classification of pre- and postoperative specimens was identical, whereas 26% of the cases showed a disagreement. Out of 48 tumors with preoperative diagnosis of an intestinal type, 10 tumors (20.8%) exhibited a diffuse growth pattern in the gastrectomy specimens; and 16% of the cases showed a disagreement of the pre- and postoperative histopathological type according to the WHO classification. Preoperative biopsy-related and surgical specimen-related Laurén classification differ in about one-quarter of the cases. Mostly, the preoperative diagnosis of an intestinal tumor type must be corrected into a diffuse or mixed type according to Laurén. Since this may have consequences for the surgical strategy, the extent of surgical resection, rebiopsies, and reconfirmation of an intestinal type should be performed at least in those cases with any doubts of this classification.

Female↗

PubMed2002

Impact of the latest TNM classification for gastric cancer: retrospective analysis on 94 D2 gastrectomies.

The aim of this study was to determine whether the latest edition of tumor-node-metastasis (TNM) classification provides reliable prognostic information. The fifth edition of TNM Classification of Malignant Tumors has introduced for gastric cancer the numeric count of involved lymph nodes whereas their topographic location was considered in earlier editions. For our study, data from 94 patients who underwent D2-gastrectomy were reviewed. The N-factor was scored according to both the Japanese Research Society for Gastric Cancer (JRSGC) classification (n) and, retrospectively, the latest TNM classification (N). Actuarial survival was calculated for both groups. The two staging systems showed similar stratification of actuarial survival with relation to N-stage; in the JRSGC classification no statistical differences were observed between n1 and n2 patients (62.7% vs. 52.5%; p = NS), whereas the 5th TNM classification showed a significant difference between N1 and N2 patients (68.5% vs. 45.0%; p = 0.04), and between N1 and the new category of N3 patients (68.5% vs. 45.0%, p = 0.03). It appears, therefore, that the numeric count of involved nodes may represent a more reliable indicator for single-case prognosis. Reclassification of all node-positive patients in our series caused an overall stage modification in 32.9% (31/94); 22 of those patients were reclassified to a less favorable stage (23.4%). In addition, 11.7% of patients (6/51) who were previously designated n1 were reclassified as N2, shifting from an expected actuarial survival after 72 months of 62.7% to 33.3%.

Adult↗

PubMed2003

Minimum number of lymph nodes that should be examined for the International Union Against Cancer/American Joint Committee on Cancer TNM classification of gastric carcinoma.

The classification of lymph node metastasis based on the number of positive nodes has been adopted in the International Union Against Cancer/American Joint Committee on Cancer (UICC/AJCC) TNM classification of gastric carcinoma. However, the N classification (for condition of the regional lymph nodes) would be underestimated when the number of examined nodes were too small. To determine the minimum number of lymph nodes to examine for a correct classification, we analyzed 926 patients undergoing curative resection for gastric carcinoma. The number of metastatic lymph nodes correlated significantly with the number of examined lymph nodes. The pN0 patients with 10 to 14 examined nodes showed a significantly higher survival rate than did those with 5 to 9 examined nodes, and they had as good a prognosis as those with 15 or more examined nodes. In the pN1 and pN2 categories, patients with 29 or fewer examined nodes tended toward lower survival rates than did patients with 30 or more examined nodes. Among the patients who were classified as stage IA, the survival rate for those with 5 to 9 examined nodes was significantly lower than that for patients with 30 or more examined nodes. Among the patients classified as stage III, those with 10 to 19 examined nodes and those with 20 to 29 examined nodes had lower survival rates than did patients with 30 or more examined nodes. In conclusion, the minimum number of lymph nodes examined for a correct pN0 classification can be reduced from 15 to 10. For pN1-3 classifications, 20 or more nodes should be examined, and examining 30 or more lymph nodes may be desirable.

Humans↗

PubMed2004

Modern diagnostics in chronic myeloproliferative diseases (CMPDs).

According to the new WHO classification a group of chronic myeloproliferative diseases (CMPDs) were defined: chronic myeloid leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia and hypereosinophilic syndrome (CEL/HES), polycythemia vera (PV), chronic idiopathic myelofibrosis (with extramedullary hematopoiesis, CIMF), essential thrombocythemia (ET), and so called CMPD/unclassifiable. As clinical features and laboratory findings differ widely between these diseases several diagnostic approaches are mandatory at diagnosis for classification and are needed also for follow up studies, especially for the measurement of minimal residual disease (MRD). We here outline the laboratory set up at diagnosis and during follow up in CMPDs with specific focus on the respective therapeutical consequences. Only by using a comprehensive diagnostic panel including cytomorphology, cytogenetics, and molecular genetic methods establishing the correct diagnosis, optimizing treatment as well as evaluating treatment response is possible in CMPDs today.

Blood Cell Count↗