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Biomedical subjects

M E Fisher

Publications and source records attributed to M E Fisher.

At least 37 records · Page 2Linked to original sources
PubMed1990

A mathematical model of cancer chemotherapy with an optimal selection of parameters.

An optimal parameter selection model of cancer chemotherapy is presented which describes the treatment of a tumor over a fixed period of time by the repeated administration of a single drug. The drug is delivered at evenly spaced intervals over the treatment period at doses to be selected by the model. The model constructs a regimen that both minimizes the tumor population at the end of the treatment and satisfies constraints on the drug toxicity and intermediate tumor size. Numerical solutions show that an optimal regimen withholds the bulk of the doses until the end of the treatment period. When a drug used is of either moderate or low effectiveness, an optimal regimen is superior to a schedule that delivers all of the drug at the beginning of the treatment. This study questions whether the current method for the administration of chemotherapy is optimal and suggests that alternative regimens should be considered.

Antineoplastic Agents↗
PubMed1990

Nonreimbursed home health care: beyond the bills.

The unprecedented growth in the home care industry over the past decade has produced a highly competitive environment for care delivery. To survive, most agencies are implementing strategies to maximize reimbursable care. This focus, while likely to improve an agency's financial situation, is fraught with potential problems. Reimbursed care represents only a small portion of the care that is required and delivered. Still, aside from anecdotes, little reporting has been done to document such additional service, much less to consider the consequences of reducing or deleting it. We selected a sample of 350 public health home care episodes throughout Virginia, and reviewed billing records to determine the number of billed home visits attached to them. We then reviewed home health records for the matching episodes and recorded all visits and other care-related activities (e.g., telephone calls, conferences, laboratory trips). Total home visits increased, with an average of 1.5 unbilled home visits per episode. In addition, 10 additional care-related activities take place per patient, none of which is billed. These findings represent one of the first attempts to quantify the amounts and types of nonbilled care delivered by nurses. This care consumes significant nursing resources and, as a result, may be destined to be reduced or totally eliminated.

Home Care Services↗
PubMed1989

Optimal insulin infusion resulting from a mathematical model of blood glucose dynamics.

Mathematical optimization techniques are applied to a simplified mathematical model of blood glucose dynamics to derive insulin infusion programs for the control of blood glucose levels in diabetic individuals. Two particular cases are discussed. First, the insulin infusion program which results in an initially high blood glucose level being reduced to acceptable levels. Second, the control of blood glucose levels following a meal, prior to which blood glucose and net blood-glycemic hormone were at their fasting levels.

Blood Glucose↗
PubMed1989

DRG ripple and the shifting burden of care to home health.

It is no secret to any nurse in community health care that the DRG system has caused major shifts in the nature of the patient load, types of patients served, and level of care technology required. Phillips et al. detail the mechanism by which the care demands of the community have changed.

Aged↗
PubMed1988

Sensitivity of Gd-DTPA-enhanced MR imaging of benign extraaxial tumors.

The effect of gadolinium diethylenetriaminepentaacetic acid (DTPA) on the sensitivity of cranial magnetic resonance (MR) imaging was measured in a prospective blinded study. Twenty-two consecutive patients with benign extraaxial tumors underwent MR imaging on a 1.5-T system without and with intravenous administration of Gd-DTPA. Readers independently interpreted the unenhanced and enhanced images without clinical information. The interpretations were compared with the anatomically verified diagnoses. Gd-DTPA improved the sensitivity of MR imaging for benign extraaxial tumors, especially in cases of residual or recurrent acoustic neuromas, multiple tumors (e.g., neurofibromatosis), or inconclusive unenhanced MR images. Enhancement with Gd-DTPA impaired the identification of a skull base tumor.

Adenoma↗
PubMed1987

Home health care: who's where?

Referrals to two home health agencies, one public and one private, were examined over a one-year period (n = 290). Clients in the public agency required greater frequency of visits, more nursing services, and care for a longer period of time than did those in the private agency. The public agency served a larger proportion of indigent and Medicaid clients. Increased service delivery with a decreased financial base may forebode an unhealthy future for traditional public home health agencies.

Health Services Needs and Demand↗
PubMed1987

[Complex preoperative diagnosis of the dissemination of stomach cancer to abdominal and retroperitoneal organs and tissues].

An analysis of 136 cases of stomach cancer led to the determination of the role and place of gamma-topography, echography, computerized x-ray tomography, angiography and laparoscopy in specified preoperative diagnosis of extra-organ spreading of primary tumors. The informative value and shortcomings of certain methods were shown. A high accuracy of the entire set of diagnostic procedures (94.8%) in the preoperative definition of stomach cancer involvement of the abdominal and retroperitoneal organs and tissues was emphasized.

Abdominal Neoplasms↗
PubMed1986

[Relation between the metastatic spread of stomach cancer and the factors characterizing the primary tumor].

The paper deals with the analysis of patterns of metastatic spread in 738 gastric cancer patients versus site, size, gross appearance and histologic pattern of tumor at presentation. The likelihood of organ involvement through dissemination or invasion by gastric tumor was determined by assessing unknown probabilities by Bayes' theorem. The probability of correct preoperative evaluation of dissemination pattern ranged 0-0.935.

Adenocarcinoma↗
PubMed1985

Impact of DRGs on home health nursing.

Home health care agencies probably will see and care for Medicare patients who need different and more intensive services than in the past because of the impact of the DRG-based system of reimbursement. Therefore, coordination between health care providers is even more critical than before. Providers must examine their clients and modify their delivery system to efficiently and effectively ensure quality health care.

Aged↗
PubMed1977

Stability in a class of discrete time models of interacting populations.

Effective Lyapunov and Lyapunov-like functions for a class of discrete time models of interacting populations are presented. These functions are constructed on the biologically meaningful principle that a viable population must absorb energy from external sources when its density is low and it must dissipate energy to the environment when its density is high. These functions can be used to establish that a discrete time model is globally stable or that its solutions are ultimately confined to an acceptable region of the state space. The latter is especially interesting when the model has chaotic solutions. These methods are applied to a single species model and a model of competition between two species.

Ecology↗