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Biomedical subjects

D Schmidt

Publications and source records attributed to D Schmidt.

At least 775 records · Page 43Linked to original sources
PubMedDate not supplied

[Analysis of prognostic factors in rhabdomyosarcoma. Preliminary univariate and multivariate results of the Cooperative Soft Tissue Sarcoma Study (CWS-81)].

The characteristics of 129 children with rhabdomyosarcoma entered into the CWS-81 study between 1981 and 1984 were examined for their relationship to prognosis. Prognosis was defined as relapse-free survival time. The trial was stratified to clinical groups depending on the surgical procedure at onset. So, each group had to be analysed separately. The patient characteristics of group I/IIA mostly related to prognosis were primary site (disease in extremities, unfavorable; paratesticular primary, favorable) and tumor infiltration into adjacent bone (bone infiltration, unfavorable). In group IIB/III the degree of tumor response within 7-9 weeks, chemotherapy exclusively given, was the only characteristic significantly related to prognosis (greater than 2/3 tumor reduction, favorable; less than 2/3 tumor reduction, unfavorable). Other prognostic factors as histological subtype, primary site, tumor diameter, lymph node involvement, bone infiltration, sex and age had no significant influence. The tumor diameter was the only characteristic with significant influence in group IV. The larger the tumor diameter, the poorer was prognosis. Furthermore, the alveolar subtype was seen predominantly in non-responding tumors of group IV. In group III, we fitted the patient characteristics in a multivariate regression model (Cox's model). The degree of tumor response within 7-9 weeks was analysed to be the main hazard function related to prognosis. In future, the degree of tumor response within a certain time can be used as the measurement of effectiveness of chemotherapy. So, in patients of group III and IV a risk adapted therapeutic procedure can be undertaken.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

[Cooperative Ewing's Sarcoma Studies 81/86: pathologico-anatomic and immunohistochemical findings and differential diagnosis of Ewing sarcoma].

158 cases of the Cooperative Ewing's Sarcoma Trials (CESS 81/86), which have been documented at the Pediatric Tumor Registry, Kiel, were studied by conventional light microscopy and immunohistochemistry. There were 77 cases of typical Ewing's sarcoma with 70 cases being located in the skeleton and 7 in soft tissues. Of the 14 cases of atypical Ewing's sarcoma 7 cases each were localized in bone and in soft tissue, respectively. In contrast to typical Ewing's sarcoma, cells of atypical Ewing's sarcoma were larger and displayed more heterochromatin. Both, typical and atypical Ewing's sarcoma reacted positively for vimentin. Other stains were negative, notably the neuron specific enolase (NSE). In 55 cases a diagnosis of malignant peripheral neuroectodermal tumor (MPNT) was made. Histologically most of these tumors resembled atypical Ewing's sarcoma. By immunohistochemistry positive reactions were found for NSE, vimentin, protein S-100, neurofilaments and glial fibrillary acidic protein. In 3 cases a diagnosis of small cell osteosarcoma was made. There were 2 cases of undifferentiated sarcoma of bone, 2 cases of soft tissue sarcoma of undetermined histogenesis and 2 cases of rhabdomyosarcoma. Of the 4 tumors which could be investigated for response to polychemotherapy, 1 each corresponded to grade II and III, respectively, and 2 to grade IV according to the classification of histologic grade of regression established by Salzer-Kuntschik et al. (1983).

Adolescent↗
PubMedDate not supplied

[Histology and prognosis of nephroblastoma--with special reference to special variants].

101 cases of Wilms' tumor (nephroblastoma) were investigated by light microscopy. In 80 cases a diagnosis of triphasic nephroblastoma was made. 21 cases were classified as special variants of Wilms' tumor. These included congenital mesoblastic nephroma (n = 5), fetal rhabdomyomatous nephroblastoma (n = 2), cystic partially differentiated nephroblastoma (n = 3), nephroblastoma with focal or diffuse anaplasia (n = 2), clear cell sarcoma or bone metastasizing renal tumor of childhood (n = 4), rhabdoid tumor (n = 2) and rhabdomyosarcomatous nephroblastoma (n = 3). Based on our own follow-up data and on information from the literature we propose to separate the group of nephroblastomas into three categories of different prognosis: 1. Nephroblastomas of low risk (congenital mesoblastic nephroma, fetal rhabdomyomatous nephroblastoma, cystic partially differentiated nephroblastoma) - in most of these cases simple nephrectomy sufficient as adequate therapy. 2. Nephroblastomas of standard risk (triphasic nephroblastomas) - therapy according to stage of disease. 3. Nephroblastomas of high risk (nephroblastomas with focal or diffuse anaplasia, clear cell sarcoma, rhabdoid tumor, rhabdomyosarcomatous nephroblastoma) - successful therapy has as yet to be developed.

Adolescent↗
PubMedDate not supplied

[Intracerebral schwannoma in a child--case report].

A case of an intracerebral, intraparenchymatous schwannoma in an 8-year-old child is presented. Clinical, radiological and histological findings as well as possible etiologies are discussed.

Cerebral Ventricle Neoplasms↗
PubMedDate not supplied

[Successful therapy of local recurrence of congenital mesoblastic nephroma].

A 3 1/2 month old girl was found to have a large abdominal tumor originating in the upper pole of the right kidney. At laparotomy the tumor had infiltrated the perirenal fat, the right lobe of the liver and the diaphragm. Partial nephrectomy was performed and the tumor was completely resected. However, an adequate safety margin could not be achieved. Histology showed a congenital mesoblastic nephroma of the cellular subtype. Postoperatively no chemotherapy was considered necessary. 11 months after diagnosis the patient had an extensive local recurrence with infiltration of the perirenal fat, mesenterium and colon. Complete resection could not be achieved and the tumor was classified as stage III. There was a striking morphological change from spindle cells in the initial tumor to malignant round cells in the relapse specimen. The patient was treated with Vincristine, Actinomycin-D and Adriblastin. Radiotherapy was not given. 38 months after relapse the patient is free of disease and developing normally. Our patient obviously had an aggressive variant of CMN. The significance of the potentially aggressive variant of CMN, atypical mesoblastic nephroma, is discussed and possibilities are suggested for management.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Supervision of home care aides.

The supervision of home care aides is of the utmost importance, since these aides provide needed services in the less controlled and out-of-sight private homes of patients. The role of the supervisor is demanding to assure compliance with accreditation, certification, and agency standards. Supervision of the paraprofessional staff also provides the opportunity to provide positive feedback as well as constructive criticism to assure that high-quality in-home services are provided to home-bound patients. Supervision also provides the opportunity to interact with the aides, show respect for them as individuals, and convey to them that they are an important member of the home healthcare team.

Community Health Workers↗
PubMedDate not supplied

Utility of free level monitoring of antiepileptic drugs.

Criteria that were developed for monitoring free (unbound) rather than total (free plus bound) concentrations of antiepileptic drugs include extensive and variable binding to plasma proteins. Phenytoin and valproic acid belong to this category. It is shown that free drug concentration is independent of total drug concentration, whereas total drug concentration depends on free concentration and free fraction. Because antiepileptic drugs are predominantly bound to albumin, free fraction will increase in the presence of hypoalbuminemia (hepatic and renal disease, burns, and pregnancy). Free fraction also increases because of saturable binding (valproic acid) and competitive binding (valproic acid displacing phenytoin). There is suggestive evidence that side effects may be more closely related to the free, rather than to the total, plasma concentration of phenytoin. The clinical evidence that side effects or therapeutic effects are better correlated to the free, rather than the total, concentration of valproic acid or carbamazepine is not yet convincing. Knowledge of the free concentration improves our understanding of therapeutic and toxic effects of low total plasma concentrations. Further clinical trials are necessary for definitive assessment of the clinical relevance for free drug monitoring of valproic acid, carbamazepine, and phenytoin in the management of epileptic patients.

Anticonvulsants↗
PubMedDate not supplied

Validation of deconvolutional analysis for the measurement of hepatic function in dogs with toxic-induced liver disease.

The extraction of the hepatobiliary radiopharmaceutical 99mTc-mebrofenin (Choletec) by the liver can be used to evaluate the severity of hepatocellular disease. The hepatic parenchymal cells extract mebrofenin from the blood by the same active transport mechanism as bilirubin. The ability of the liver to extract 99mTc-mebrofenin is a measure of hepatic parenchymal cell function. In this study, we induced hepatocellular disease by administration of a hepatotoxic drug and compared a direct method of determining the hepatic extraction of 99mTc-mebrofenin to hepatic extraction fraction derived from deconvolutional analysis. We also compared both methods of calculating the hepatic extraction of 99mTc-mebrofenin to liver histopathology. Hepatic extraction fraction derived from deconvolutional analysis correlated very well to the direct measurement technique (R=0.922, p < 0.001). Both methods of determining hepatic extraction correlated well to quantitative histopathology, having the same correlation coefficient and p values. (R=-0.833, p=0.003). As the hepatic extraction 99mTc-mebrofenin decreased, the severity of the histopathologic lesions of the liver increased in a linear fashion. There was a significant correlation of the hepatic excretion T1/2 to quantitative histopathology (R=0.949, p < 0.001). The hepatic excretion T1/2 increased as the severity of the histopathologic lesions of the liver increased. Hepatic extraction (HEF) and excretion of 99mTc-mebrofenin are good predictors of the severity of hepatocellular damage in toxic induced liver disease. This study helps validate the premise that HEF derived from deconvolutional analysis is a good predictor of the actual first pass hepatic extraction of 99mTc-mebrofenin.

Aniline Compounds↗
PubMedDate not supplied

Quantitative assessment of surgically induced mitral regurgitation using radionuclide ventriculography and first pass radionuclide angiography.

Radionuclide ventriculography has been used in humans to evaluate valvular incompetency. The stroke volume ratio, derived from the radionuclide ventriculogram, is used to quantify the severity of mitral regurgitation (MR). Previous studies conducted in humans have shown that left to right stroke volume ratio increases as the severity of MR increases. In this study, we evaluated radionuclide ventriculography as a noninvasive method to detect MR in dogs with surgically created mitral insufficiency. Six male and three female adult, conditioned mongrel dogs were used. Scintigraphic studies were performed prior to and 4 weeks after surgically created MR. Because of the overlap of the left and right ventricles when viewed from a left lateral position, we combined data from a first-pass radionuclide angiocardiogram with the radionuclide ventriculogram to obtain a corrected stroke volume ratio. Blood flow transit parameters were also derived from the first-pass radionuclide angiocardiogram. Standard left ventricular functional indices were also measured from the radionuclide ventriculogram. On the left lateral view of the heart, 25 to 30% of the right ventricular volume overlaps the left ventricle. After correcting for the overlap, the stroke volume ratio of normal dogs was 1.17+/-0.178 (mean+/-SD), which increased to 2.06+/-0.41 (mean+/-SD) (p < .001) 4 weeks after creation of MR. The was no significant change in left ventricular ejection fraction or peak rate of ejection following MR. The transit times of blood through the left ventricle were measured from the first-pass radionuclide angiocardiogram and were expressed as half-time clearance, peak clearance rate, and time to peak clearance rate. The baseline half-time clearance was 2.07+/-0.71 s (mean+/-SD), which increased to 6.70+/-4.89 s (mean+/-SD) (p = .02) after creation of MR. The baseline peak clearance rate was 49.75+/-8.96 cts/s (mean+/-SD), which decreased to 23.12+/-6.84 cts/s (mean+/-SD) (p < .001) after creation of MR. Stroke volume ratios significantly increased following creation of MR. Blood flow transit through the left ventricle slowed following creation of MR. The variability of these parameters were small in the baseline studies, suggesting these techniques may be clinically useful to gauge the severity of MR in dogs.

Angiocardiography↗
PubMedDate not supplied

Renal nuclear medicine: a review.

Renal nuclear medicine is used to evaluate renal function and morphology. Renal scintigraphy is the best imaging modality for evaluation of functional parameters such as glomerular filtration rate and effective renal plasma flow. The commonly used renal radiopharmaceuticals are reviewed. Both imaging and non-imaging techniques are presented. Specific applications of renal nuclear medicine are discussed.

Animals↗
PubMedDate not supplied

Fanconi syndrome in a Labrador retriever.

A 2-year-old male Labrador Retriever was presented to the University of Missouri Veterinary Teaching Hospital with the primary complaints of polydipsia, polyuria, and joint or muscle pain. Low blood urea nitrogen concentration, hyperchloremia, and marked proteinuria were the only abnormalities in a serum biochemical profile and urinalysis. Decreased creatinine clearance and increased renal fractional excretion of sodium, potassium, calcium, and phosphorus were detected by renal clearance studies. Increased excretion of most amino acids was found by amino acid analysis of urine, but not all amino acids were lost with equal magnitude. Amino acids with secondary amino groups or basic side chains were lost at increased rates, whereas those with acidic side chains were not. These differences could be related to defects in specific renal amino acid transport mechanisms. Identification of these transport mechanisms may allow for pharmacologic intervention at the point of renal loss to alleviate clinical signs of disease.

Amino Acids↗
PubMedDate not supplied

On the origin of the non-haemic iron transferrin ESR signal: ESR investigations on histidine-iron-ascorbic acid systems.

The nature of the ferric high spin iron complex located at g = 4.3 has been investigated by means of electron spin resonance spectroscopy. It could be shown that the iron is bound to two histidines, three ascorbic acids, and one bicarbonate. This agrees well with previous findings according to which the ligand field of iron is composed mainly of oxygen and nitrogen atoms. Another low-field signal located at g = 9.5 appears always concomitantly with the g = 4.3 signal. It should be due, therefore, to a transition between the two sublevels of the low-lying Kramers doublet in one principal direction.

Ascorbic Acid↗
PubMedDate not supplied

On the origin of the non-haemic iron transferrin ESR signal: ESR investigations on histidine-iron-citric acid systems.

The nature of the high spin ferric iron complex located at g = 4.3 has been investigated by means of electron spin resonance spectroscopy and polarography. It could be shown that two complexes each exist in the acid and alkaline pH region, and that the iron is bound to two histidines, three citric acids, and probably to one bicarbonate. These results agree well with previous findings according to which the ligand field of iron should be composed mainly of oxygen and nitrogen atoms. Another low-field signal located at g = 3.6 appears in the pH range from 2 to 7 only and exhibits its maximum where the g = 4.3 signal has its minimum. Its exact nature is still unknown but it seems to represent some intermediate state of the ternary Fe3+-histidine-citric acid complex. When citric acid is used, the spin concentration seems to be always larger than in the case of ascorbic acid. Since the effect obtained with ascorbic acid and citric acid seems to be similar, it may be concluded that the biological function of both of the acids might be somehow related to each other.

Ascorbic Acid↗
PubMedDate not supplied

ESR investigations on the modification of the ascorbic acid-erythrocyte interaction by ferrous ions.

An ascorbic acid-erythrocyte interaction results in the formation of the semidehydroascorbate (SDA) radical and an increase in spin concentration. Addition of a more than ten-fold concentration of Fe2+ (as FeSO4) to such a system compensates the effect produced by ascorbic acid, that is the electron spin resonance spectrum obtained resembles very closely that of erythrocytes only. With the disappearance of the SDA radical a high spin ferric ion signal appears concomitantly at g = 4.3.

Ascorbic Acid↗