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Biomedical subjects

A Postma

Publications and source records attributed to A Postma.

At least 55 records · Page 3Linked to original sources
PubMed1992

Quality of life in bone tumor patients comparing limb salvage and amputation of the lower extremity.

In 33 long-term survivors of lower extremity bone cancer quality-of-life data were studied following limb salvage compared to amputation. Self-report questionnaires, semistructured interviews and visual analog scales were used to measure psychoneurotic and somatical distress, activities of daily living, self-esteem, and adjustment to illness. Fourteen patients with limb salvage (age 13-56 years, median 24) and 19 patients with an amputation (age 21-53 years, median 27) were evaluated 2-17 years (median 10 years) after surgery. The differences between the two groups were not statistically significant. However, physical complaints were reported more often by limb salvage patients, whereas the amputees showed a trend toward lower self-esteem and isolation in social life, due to their disability. Both groups felt equal diminution of quality of life and disability as measured on the visual analog scale. These findings could support the cosmetic advantage of limb salvage compared to amputation.

Adolescent↗
PubMed1992

The effects of noise masking and required accuracy on speech errors, disfluencies, and self-repairs.

The covert repair hypothesis views disfluencies as by-products of covert self-repairs applied to internal speech errors. To test this hypothesis we examined effects of noise masking and accuracy emphasis on speech error, disfluency, and self-repair rates. Noise reduced the numbers of disfluencies and self-repairs but did not affect speech error rates significantly. With accuracy emphasis, speech error rates decreased considerably, but disfluency and self-repair rates did not. With respect to these findings, it is argued that subjects monitor errors with less scrutiny under noise and when accuracy of speaking is unimportant. Consequently, covert and overt repair tendencies drop, a fact that is reflected by changes in disfluency and self-repair rates relative to speech error rates. Self-repair occurrence may be additionally reduced under noise because the information available for error detection--that is, the auditory signal--has also decreased. A qualitative analysis of self-repair patterns revealed that phonemic errors were usually repaired immediately after their intrusion.

Adult↗
PubMed1992

Error monitoring in people who stutter: evidence against auditory feedback defect theories.

Several theories purport that people who stutter suffer a speech-auditory feedback defect. The disordered feedback creates the illusion that some kind of error has intruded into the speech flow. Stuttering then results from actions aimed to correct the suspected, but nonexistent, error. These auditory feedback defect theories thus predict deviant error detection performance in people who stutter during speech production. To test this prediction, subjects who stuttered and those who did not had to detect self-produced (phonemic) speech errors while speaking with normal auditory feedback and with the auditory feedback masked by white noise. The two groups did not differ significantly in error detection accuracy and speed, nor in false alarm scores. This opposes auditory feedback defect theories and suggests that the self-monitoring processes of people who stutter function normally. In a condition in which errors had to be detected in other-produced speech, i.e., while listening to a tape recording, subjects who stuttered did detect fewer errors. Whether this might signal some general phonological problem is discussed.

Adult↗
PubMed1992

MRI or CT in the preoperative diagnosis of bone tumours.

The value of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of bone tumours was investigated in a prospective study of 25 patients. MRI is superior to CT because it permits multidirectional exposures. Moreover, the tumour can be readily distinguished from the neurovascular structures without injection of contrast medium. MRI gives better contrast than CT, making it possible to study the relationship to the soft tissues, bone marrow and joints more accurately. On the other hand, CT gives a better picture of the destruction of cortical bone. With neither MRI nor CT can the exact tumour length be measured. Neither MRI nor CT permits an exact, reliable diagnosis. Owing to the relatively slow exposure technique in combination with respiratory movements, depiction of the thoracic wall is less satisfactory with MRI than with CT. If both techniques are available, MRI is preferred. In view of the fact that MRI apparatus is still less widely available, it should be borne in mind that CT also allows an adequate investigation of skeletal lesions.

Adolescent↗
PubMed1991

Manual reaction times and error rates in stutterers.

In this study 18 stutterers and 18 nonstutterers were presented trials on which they should press a button as fast as possible, intermixed with trials which required no responding. Stutterers had slightly faster reaction times but also made slightly more errors, that is, they tended to press the button when they should not have done so. As neither difference was significant, it was concluded that stutterers did not differ from normal speakers in manual reaction speed, nor did they choose a different speed-accuracy trade-off criterion for the given task.

Adult↗
PubMed1990

An extendable modular endoprosthetic system for bone tumour management in the leg.

A modular endoprosthetic system has been developed at the Groningen University Hospital and the University of Twente. The system can bridge a defect resulting from the resection of a malignant bone tumour which has developed around the knee joint of a child. Since the other healthy leg continues to grow, the system includes an element whose length can be adjusted non-invasively by using an external magnetic field. In addition to this lengthening element, there are one hip and two knee components, connectors of various lengths, and fixation elements. The paper describes the elements of the modular endoprosthetic system. Tables are created by means of which the elemental composition of such an endoprosthesis can be determined for each individual patient.

Adolescent↗
PubMed1989

Epithelioid sarcoma or malignant rhabdoid tumor of soft tissue? Epithelioid immunophenotype and rhabdoid karyotype.

Two children and one young adult with extremity sarcomas demonstrating an aggressive clinical behavior are described. Histologically, all three tumors displayed features compatible with a deep-seated epithelioid sarcoma or with a malignant rhabdoid tumor of soft tissue. Immunohistologically, both vimentin and epithelial antigens were demonstrated; however, no desmin was detectable. In all three cases, the DNA profile was diploid. In one case, a trisomy of chromosome 2 was found in the tumor cells, a phenomenon also observed in embryonal rhabdomyosarcomas. It is concluded that, although the immunohistologic findings support the epithelioid character of the tumors, this chromosomal finding suggests a relationship with rhabdomyosarcomas and justifies the designation of rhabdoid.

Adult↗
PubMed1989

Epithelioid sarcoma in children and adolescents: a report of four cases.

Epithelioid sarcoma is an uncommon soft tissue tumor, most prevalent in the extremities of young adults. Youth has been described as a favorable prognostic factor. We describe four patients (two children aged 10 years and two adolescents aged 18 years) with extremity epithelioid sarcoma. Both 10-year-old children had rapid disease evolution and died 3 and 6 months after the diagnosis was made. Both tumors were strict diploid at DNA flow cytometry, but one had an abnormal karyotype (trisomy 2). Both adolescents are disease-free 18 months and 18 years after combined treatment consisting of local resection, regional lymph node dissection, and isolated regional perfusion with cytostatic agents.

Adolescent↗
PubMed1989

Magnetic resonance imaging (MRI) in evaluating in vivo response to neoadjuvant chemotherapy for osteosarcomas of the extremities.

Limb-saving procedures for patients with osteosarcomas of the extremities are based on the anatomical localization and extent of the tumor. The effectiveness of neoadjuvant chemotherapy, high-dose methotrexate (HD MTX), was prospectively analyzed in patients using magnetic resonance imaging (MRI) and histologic evaluation of bone biopsies. Evaluation of in vivo response to neoadjuvant chemotherapy for osteosarcomas with MRI is a method which seems promising in predicting the histologic tumor reaction.

Adolescent↗
PubMed1987

An analysis of histology and DNA-ploidy in primary wilms tumors and their metastases and a study of the morphological effects of therapy.

In children with Wilms' tumours the length of survival is greatly influenced by success in preventing or controlling metastatic disease. The current study focuses on the morphological aspects of metastases when compared with the primary tumour. In 8 patients it appeared that blastema is the most likely component to metastasize, whereas epithelial and stromal components were hardly, if at all, represented in metastases. Furthermore, flow cytometric DNA ploidy determinations on 4 cases showed that both the primary tumours and the metastases had stemlines in the diploid and low aneuploid (hyperdiploid) range. Finally, in four cases the influence of therapy on morphology of the primary tumours was analyzed. In these cases blastema seemed to be the component most sensitive to therapy. Thus, blastema seems to play a central role in prognosis of Wilms' tumours; either reacting to therapy or, if insensitive, by metastasizing.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

The treatment of primary tumors of the femur with chemotherapy (if indicated), resection and reconstruction with an endoprosthesis.

The treatment protocol of 15 patients with a primary tumor of the femur, including osteosarcoma, malignant fibrous histiocytoma and chondrosarcoma is presented. All patients had been selected for resection and reconstruction with an endoprosthesis. An endoprosthesis was implanted in 12 patients. The results of this type of treatment appear to be satisfactory. In eight osteosarcoma cases resection and reconstruction with an endoprosthesis combined with preoperative and postoperative chemotherapy, according to Rosen, were performed. Follow-up in all 15 patients, varying from 1.4 to 6.0 years, showed no evidence of disease in 12 patients. Three patients had died. Function of the involved leg was satisfactory in most cases. The advantage and disadvantages of the use of an endoprosthesis are discussed as well as complications in this series of patients.

Adolescent↗
PubMed1984

A pertrochanteric fracture in an adolescent treated for an osteogenic sarcoma of the shaft of the femur with chemotherapy, tumour resection and endoprosthesis.

Osteosarcomas of the femur are treated nowadays, if possible, by chemotherapy, resection of the tumor and reconstruction with an endoprosthesis. There is not only a risk of epiphyseal fractures in the long bones due to chemotherapy but also of a fracture in the remnant of the treated femur. These fractures should be treated conservatively because of the risk of infection and non-union if treated operatively.

Adolescent↗
PubMed1983

Five years' experience in access surgery for polychemotherapy. An analysis of results in 100 consecutive patients.

In 100 consecutive patients with various malignancies, 142 operations were performed to establish an arteriovenous fistula giving vascular access for chemotherapy. The fistula of choice was always an end-to-side fistula between the cephalic vein and the radial artery (radiocephalic fistula). A fistula of this type was established in 88 operations on 76 patients and functioned well in 64% of this group. In 29 patients in whom this fistula failed or was not feasible, an elbow fistula was performed in 32 operations and functioning well in 59%. In 13 patients whose arms offered no alternative possibility, 15 long saphenous vein (LSV) autografts were implanted in the inguinal region. A radiocephalic fistula was successfully performed in 77% of the patients who had received preoperative chemotherapy during less than 4 weeks, versus 26% of those who had received preoperative chemotherapy during a longer period. The radiocephalic fistula is the fistula of choice to gain vascular access for chemotherapy. It has proved necessary to perform this operation before chemotherapy is started. When this type of fistula is not feasible, alternatives are an elbow fistula or an (LSV) autograft in the inguinal region.

Adolescent↗
PubMed1983

Radionuclide bone scintigraphy in patients with histiocytosis X.

The term histiocytosis X (HX) refers to a spectrum of disorders varying from unifocal eosinophilic granuloma (UEG), multifocal eosinophilic granuloma (MEG), to the Abt-Letterer-Siwe syndrome. In a series of 16 patients with different types of HX and skeletal lesions, whole body bone scintigraphy was performed at the time of diagnosis and during follow up. Results were compared with radiographic findings. In patients with MEG with or without extra-skeletal dissemination bone scintigraphy revealed cold spots or hot spots, but half of the lesions were not visualised scintigraphically, resulting in false negative scans. In UEG the lesions were visualised as areas of increased uptake or as a cold spot with increased uptake at its borders. No false negative scans were encountered. The reliability of skeletal scintigraphy in patients with HX seems to depend on the type of the disorder: in UEG bone scintigraphy is a safe procedure. In MEG false negative bone scans have to be expected, and radiography is superior.

Adult↗
PubMed1982

[Supportive treatment in children with acute lymphatic leukemia].

Prognosis of childhood ALL has considerably improved during the last two decades, due to both effective treatment and advances in supportive care. Prevention and treatment of infections, blood component therapy, toxicity of chemotherapy, nutritional support, control of pain and psychosocial care are successively discussed.

Blood Cells↗