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Biomedical subjects

A Stark

Publications and source records attributed to A Stark.

At least 91 records · Page 5Linked to original sources
PubMed1987

Forecasting client transitions in British Columbia's Long-Term Care Program.

This article presents a model for the annual transitions of clients through various home and facility placements in a long-term care program. The model, an application of Markov chain analysis, is developed, tested, and applied to over 9,000 clients (N = 9,483) in British Columbia's Long Term Care Program (LTC) over the period 1978-1983. Results show that the model gives accurate forecasts of the progress of groups of clients from state to state in the long-term care system from time of admission until eventual death. Statistical methods are used to test the modeling hypothesis that clients' year-over-year transitions occur in constant proportions from state to state within the long-term care system. Tests are carried out by examining actual year-over-year transitions of each year's new admission cohort (1978-1983). Various subsets of the available data are analyzed and, after accounting for clear differences among annual cohorts, the most acceptable model of the actual client transition data occurred when clients were separated into male and female groups, i.e., the transition behavior of each group is describable by a different Markov model. To validate the model, we develop model estimates for the numbers of existing clients in each state of the long-term care system for the period (1981-1983) for which actual data are available. When these estimates are compared with the actual data, total weighted absolute deviations do not exceed 10 percent of actuals. Finally, we use the properties of the Markov chain probability transition matrix and simulation methods to develop three-year forecasts with prediction intervals for the distribution of the existing total clients into each state of the system. The tests, forecasts, and Markov model supplemental information are contained in a mechanized procedure suitable for a microcomputer. The procedure provides a powerful, efficient tool for decision makers planning facilities and services in response to the needs of long-term care clients.

Aged↗
PubMed1987

Scaphoid nonunion treated with the Matti-Russe technique. Long-term results.

Forty-three patients with scaphoid pseudarthrosis were surgically treated using the Matti-Russe technique. Twenty-seven patients were examined seven to 17 years after surgery (mean, 12 years). The interval between trauma and operation of the pseudarthrosis was 40 months. Before operation, all patients were unable to do any work because of pain. Fracture healing was observed in 22 cases (81%). Radiocarpal osteoarthrosis was present in 18 cases, compared with eight before operation. Radial deviation and extension was impaired, and pronation and supination was unaffected, compared with the healthy side. Twenty-four patients were satisfied with the operative result and none felt worse. All patients but one could return to work. The Matti-Russe method proved satisfactory in 24 of 43 patients available for long-term follow-up evaluation.

Adult↗
PubMed1987

Intestinal anastomosis after preoperative radiation therapy for carcinoma of the rectum.

A retrospective review was conducted on 133 patients who underwent anterior resection and primary intestinal anastomosis for adenocarcinoma of the rectum from 1973 to 1983 at the Baystate Medical Center. Forty patients received a moderate dose, 4,500 rads, of radiation therapy preoperatively. Twenty-six of these patients (65 per cent) underwent protective colostomy at operation. An additional 93 patients underwent an operation without radiation and 38 of these (42 per cent) had a colostomy. We found no significant difference between patients who did or did not undergo radiation therapy in the over-all rate of complications (25 per cent for those who underwent radiation and 29 per cent for those who did not). Furthermore, there was no significant difference in anastomotic leak rates between the two groups (10 and 7 per cent respectively), even after controlling for the presence of a protective colostomy. We did find that leak rates for both groups were markedly higher for patients with a colostomy (14 per cent) than for patients without (1 per cent) (p less than 0.005). We conclude that a moderate dose of radiation therapy preoperatively does not increase the risk of anastomotic leakage or other operative complications with anterior resection. Colorectal intestinal anastomosis may be safely performed without routine colostomy after planned preoperative adjuvant radiation therapy if the anastomosis is technically satisfactory.

Animals↗
PubMed1986

Recent trends in mesothelioma incidence in the United States.

Mesothelioma incidence rates based on data from population-based cancer registries in New York State (exclusive of New York City), Los Angeles County, California, and the SEER Program of the National Cancer Institute were analyzed for trends, using original cancer registry diagnoses. Results indicate a significant increase in incidence during 1973-80 for pleural mesothelioma among white males older than 55 at time of diagnosis but not for other age-race-sex-site subgroups. A histopathologic review of New York State and Los Angeles County cases by two independent pathologists, expert in the diagnosis of mesothelioma, lowered the overall estimates but a significant upward trend remained. The observed trend does not appear to be related to changes in diagnostic practice. The results of a five-member panel of expert pathologists will be published in a separate methodology paper.

Adolescent↗
PubMed1986

Human osteogenic sarcoma: fine structural localization of adenosine triphosphatase.

The localization of ATPases in 7 osteogenic sarcomas of osteoblastic, chondroblastic and fibroblastic type was investigated at the fine structural level using two types of substrates: one with lead as capturing ion and one with strontium (the latter presumed to reveal sites of Na+-K+-dependent transport ATPase). Reaction product with the lead-ATP medium was located on the plasma membrane and the membranes bordering subjacent vesicles and vacuoles in all the various types of osteoblastlike and fibroblastlike cells and also in types 1 and 3 chondroblastlike cells, and multinucleated giant cells believed to be neoplastic. Furthermore, deposits of reaction product were demonstrated in lysosomelike organelles in all the aforementioned cells. Except in the case of chondroblastlike cells, precipitates marking the localization of enzyme were confined to areas of the plasma membrane where adjacent cells were closely applied (the free surface lacked precipitates). In chondroblastlike cells the reaction product was usually deposited along the whole plasma membrane. Presence of L-Homoarginine or L-Tetramisole in the incubation medium in concentrations that have been shown to completely abolish alkaline phosphatase activity did not affect the occurrence of the reaction product with ATP as substrate indicating that the enzyme hydrolysing ATP was substrate-specific. Reaction product marking sites of Na+-K+-dependent ATPase was confined to plasma membranes and lysosomes of cells in vessel walls. The observations strengthen the notion obtained in studies on the localization of alkaline phosphatase, namely that osteoblastlike, chondroblastlike, and fibroblastlike cells in osteogenic sarcomas are histogenetically related to one another and to those multinucleated giant cells that presumably are of a neoplastic nature.

Adenosine Triphosphatases↗
PubMed1986

Quantitation of the nuclear DNA content in tissue prepared for electron microscopy.

The possibility of determining the cellular DNA content in tissue prepared for electron microscopy (EM) was investigated. Comparative cell population DNA analyses of deparaffinized and Epon-embedded sections of equal thickness (2 micron) from the same tumor (osteosarcoma) showed almost identical DNA distribution curves. The methodologic prerequisites for both EM and DNA analyses of identical cells was then investigated. Using a special technique involving consecutive sections of 500-600 A and 2-micron thickness for EM morphology and Feulgen staining, respectively, nuclear parts of identical cells could be identified in both types of sections. Thus, cells selected in ultrathin sections could be identified in corresponding Feulgen-stained Epon-embedded sections for cytophotometric DNA analysis. All normal cells (lymphocytes, fibroblasts, macrophages), as defined and selected at the ultrastructural level, proved to be diploid (with normal DNA content) as determined in the corresponding Feulgen-stained Epon-embedded sections, whereas all analyzed osteosarcoma cells, except one, were aneuploid. The results indicate that 2-micron thick Feulgen-stained, Epon-embedded specimens from osteosarcoma, previously fixed in glutaraldehyde and OsO4, may be used for cytophotometric DNA measurements. Since aneuploidy is almost exclusively found in malignant cells, this criterion may serve as a marker for such cells. Consequently, whenever it is questionable whether in a mixed population a given cell selected for ultrastructural study is malignant or not, DNA cytophotometry may give decisive information, provided aneuploidy can be demonstrated.

Bone Neoplasms↗
PubMed1986

Non-union of the scaphoid treated with styloidectomy and compression screw fixation.

17 patients were re-examined 13 to 19 years (mean 16 years) after operation for non-union of the scaphoid. A standardized method including styloidectomy and compression screw fixation according to McLaughlin was used. The mean interval between trauma and operation was 34 months. All patients were male and the mean age at surgery was 31 years. Bone union was obtained in 65% (11/17) and radio-carpal arthrosis was found in 83% (14/17) compared with 41% (7/17) at the time of operation. Impaired motion as well as marked decrease in strength was noted in comparison with the healthy side. 88% of the patients were satisfied with the result. All returned to and continued in their previous occupation. The McLaughlin method proved to be clinically beneficial in spite of a relatively high percentage of persistent non-unions.

Adult↗
PubMed1985

Survival following moderate-dose preoperative radiation therapy for carcinoma of the rectum.

We performed a retrospective study of patients with carcinoma of the rectum or rectosigmoid undergoing surgical resection. Forty-two patients received adjuvant preoperative radiation therapy (4000-4500 rad). One hundred twenty patients underwent surgical resection alone. Survival of radiation patients was significantly improved over that of Surgery Only patients, even after adjusting for nontreatment factors using Cox regression. Crude 5-year survival was 63% for radiation patients (74% adjusted) compared to 46% for surgery-only patients (48% adjusted) (P less than 0.025). Radiation patients also had longer disease-free survival than surgery-only patients (P less than 0.05) and fewer recurrences (14% versus 37%; P less than 0.025). Fewer radiation patients had lymph nodes involved with tumor than surgery-only patients (20% versus 35%; P = 0.07). Although 71% of radiation patients experienced radiation reactions, these were primarily mild and transitory. We believe that preoperative radiation is an effective and safe adjunct to surgery in the treatment of rectal cancer and that its use can lead to improved survival rates.

Aged↗
PubMed1985

Concurrent T-cell lymphocytic lymphoma and malignant histiocytosis.

A case in which both malignant histiocytosis and T-cell lymphocytic lymphoma occurred together is presented. Examples of malignant histiocytosis-like syndromes associated with lymphoreticular malignancies have been previously reported. Many of these represent reactive haemophagocytic syndromes, probably virally induced. The considerable degree of cytological atypia and frequent mitotic figures seen in the histiocytes in this case were indicative of a true malignant histiocytosis.

Adult↗
PubMed1985

Human osteogenic sarcoma: fine structure of hard tissue areas.

The structure of hard tissue areas (with osteoid and calcified matrix) in 10 osteoblastic, chondroblastic, and fibroblastic osteogenic sarcomas was studied in the electron microscope. Neoplastic cells commonly associated with these areas and presumably actively involved in the production of hard tissue were osteoblast-like cells types 1 and 3, chondroblast-like cells type 1, and fibroblast-like cells, as defined and characterized in previous studies. The cells differed from those in soft tissue areas of osteogenic sarcomas in but one respect: they usually showed presence of irregular extrusions at their surfaces. Other types of osteoblast-like and chondroblast-like cells occurred rarely or not at all. Two types of multinucleated giant cells were recognized in these areas, one showing a fine structure reminiscent of that in osteoclasts, the other probably being of a neoplastic nature and engaged in the production of the calcifying matrix. The evidence suggested that neoplastic osteoblast-like, chondroblast-like, and fibroblast-like cells as well as certain multinucleated giant cells might all be involved in the mineralization process and/or the formation of osteoid in osteogenic sarcomas. Although phenotypically of highly variable appearance, all these different cells may thus functionally (and probably histogenetically) be closed related. The mineralization process in the tumor tissue appeared to be a modification of what occurs in normal ossification, possibly with an alternative or complementary pathway involving the production of spherical bodies with layered contents.

Adolescent↗
PubMed1985

Human osteogenic sarcoma: fine structural localization of alkaline phosphatase.

The localization of alkaline phosphatase in eight osteogenic sarcomas of osteoblastic. chondroblastic, and fibroblastic type was investigated at the fine structural level using beta-glycerophosphate as substrate and lead as capturing ion. Final product marking localization of alkaline phosphatase was deposited over plasma membranes and associated subplasmalemmal vesicles and vacuoles in various types of osteoblastlike, chondroblastlike, and fibroblastlike cells as well as certain multinucleated giant cells. Presence of L-homoarginine or L-tetramisole in the incubation medium, and incubation at 65 degrees C, prevented the deposition of final product, suggesting that the enzyme studied was "bone specific." The evidence obtained was compatible with the notion that the different cells showing presence of reaction product were functionally and histogenetically closely related and all were likely to be capable of bone production.

Adolescent↗
PubMed1985

Forecasting demand for long-term care services.

This article analyzes three methods used to forecast the transition of long-term care clients through a variety of possible home and facility placements and levels of care. The test population (N = 1,653) is derived from the larger population of clients admitted in 1978 to British Columbia's newly established Long-Term Care program. The investigators have accumulated 5 years of service-generated data on moves, discharges, and deaths of these clients. Results show that the first-order Markov chain with stationary transition probabilities yields a superior forecast to state-by-state moving average growth and state-by-state regression analyses. The results of these analyses indicate that the Markov method should receive serious consideration as a tool for resource planning and allocation in long-term care.

Aged↗
PubMed1985

[New derivatives of 10,11-dihydro-5H-dibenz[b,f]azepine with antiarrhythmic action].

After an introduction about the importance of the 10, 11-Dihydro-5H-dibenz[b,f]azepine system for the drug research and according to experiences about the change of pharmacodynamic effects in the field of the phenothiazine bases by dialkylaminoacyl substitution in the following report some new 3-carbalkoxyamino-5-omega-aminoacyl-10,11-dihydro-5H-dibenz[b,f]++ +azepines and their intermediates for synthesis are described. In result of pharmacological investigations which showed antiarrhythmic activities the substance 3-carbethoxyamino-5-dimethylaminoacetyl-10,11-Dihydro-5H-dib enz[b, f]azepine X HCl (GS 015, AWD 19-166, Bonnecor) was selected for clinical tests. For studying the biotransformation of this substance the expected main metabolites were prepared by chemical synthesis.

Animals↗
PubMed1985

[Antiarrhythmic effectiveness of 3-carbalkoxyamino-5-(omega-aminoacyl)-10,11-dihydro-5H-dibenz-[b,f]- azepines].

The derivatives of a novel structure series of dibenzazepines dispose of intense antiarrhythmic properties. The relations between structure and effect in comparison with the antiarrhythmically active derivatives of phenothiazine (Ethmozine) are discussed. When substituting the beta-aminopropionyl chain with cyclic residue by means of a dimethylaminoacyl chain there appears a marked antifibrillatory action besides of the intense antiarrhythmic one. The compound 17, the 3-carbethoxyamino-5-dimethylaminoacetyl-dibenzazepine, proved to be the most efficacious compound in the course of the basic screening on two models: action on the effective refractory period in the rabbit's atrium and aconitin-induced arrhythmia in the conscious rat. In comparison with Ethmozin, an antiarrhythmic agent of the phenothiazine type, 17 shows a somewhat lower efficacy in case of i.v. application, but a distinctly intenser one was stated after oral administration. A profound test on the models: two-step coronary ligature in the dog according to Harris and electrofibrillation in the cat's heart, revealed an equally intense antiarrhythmic action but a considerably intenser antifibrillatory one. Therefore the compound 17 (abbreviated designation in the USSR: GS 015 or in the GDR: AWD 19-166) was provided for a thorough pharmacological and toxcological study.

Animals↗