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Biomedical subjects

M Stone

Publications and source records attributed to M Stone.

At least 19 recordsLinked to original sources
PubMed1992

Automated detection of the tongue surface in sequences of ultrasound images.

An image processing system has been developed for a Macintosh II personal computer. It is designed to process sequences of sagittal tongue sections that are digitized in real time and stored in standard tagged image file format (TIFF). The successive processing steps are: (a) a low-pass filter for noise reduction, (b) a resampling of the sector of interest in polar coordinates, (c) a matched filter (vertical differentiator) for the enhancement of the tissue/air interface in the surface region of the tongue, and (d) an extraction of border points by searching for an optimal radial path along the angular dimension. This latter task is achieved by dynamic programming, which has the following advantages. First, due to the use of a global criterion to guide the detection, it is very robust. Second, as a result of certain restrictions of the allowable transitions, the extracted contours are smooth. Finally, the method permits the specification of particular predefined contour points. This system was implemented in a program that can handle image sequences in a fully automatic mode. Results obtained using ultrasound data are presented.

Humans↗
PubMed1991

Phase I immunotoxin trial in patients with B-cell lymphoma.

Fifteen patients with refractory B-cell lymphoma were treated in a Phase I dose escalation clinical trial with a highly potent immunotoxin consisting of the Fab' fragment of a monoclonal anti-CD22 antibody (RFB4) coupled to chemically deglycosylated ricin A chain. All patients had low, intermediate, or high grade non-Hodgkin's lymphoma. The immunotoxin was administered i.v. in two to six doses at 48-h intervals. The peak serum concentration and the t1/2 were not dose dependent among patients and averaged 1.3 micrograms/ml and 86 min, respectively. Three patients made antibody against A chain, and a fourth made antibody against both A chain and mouse immunoglobulin. Antibody responses were low (less than or equal to 85 micrograms/ml) in three patients and were not detected until 1 mo after treatment. The maximum tolerated dose of the immunotoxin was 75 mg/m2. Dose-related toxicities included vascular leak syndrome, fever, anorexia, and myalgia. Dose-limiting toxicities included pulmonary edema and/or effusion, expressive aphasia, and rhabdomyolysis (resulting in reversible kidney failure). There was no evidence of liver dysfunction. Partial responses were achieved in 38% of evaluable patients, and in those patients who had greater than 50% CD22+ tumor cells, 50% of the patients achieved a partial response. Clinical responses were not related to tumor grade and were generally transient, lasting between 1 and 4 mo.

Adult↗
PubMed1991

A pilot study of sphincter-sparing management of adenocarcinoma of the rectum.

After analysis of 26 prospectively accrued patients with distal rectal adenocarcinomas who underwent sphincter preservation treatment, we have concluded that tumors that invade only the submucosa can safely be treated with surgery alone and that tumors that invade the muscularis or further can be safely treated with surgery combined with chemoradiotherapy. None of the patients had either local or distant recurrence, with a median follow-up of 21 months. All patients have been fully continent. The results, although preliminary, imply that resection of distal rectal adenocarcinoma with sphincter preservation, and adjuvant therapy when appropriate, have achieved local and distant control equal to the conventional Miles' abdominoperineal resection, but without the need for a permanent colostomy.

Adenocarcinoma↗
PubMed1991

Elimination of clonogenic tumor cells from bone marrow using methylprednisolone (MP) and etoposide VP16: an in vitro pharmacologic study.

The ability to eliminate malignant cells from bone marrow (BM) while retaining sufficient numbers of normal progenitors to ensure engraftment, may well establish the future of autologous BM transplantation (ABMT) for hematologic malignancies. In this study, we describe the effects of methylprednisolone (MP) and etoposide (VP16) alone or in combination on 5 tumor cell lines (HL-60, a promyelocytic cell line; Molt-4, a T cell leukemia; Daudi, a Burkitt's lymphoma and R10/8226 and R40/8226, doxorubicin-resistant myeloma cell lines). The tumor cell kill efficiency of the drugs was assayed using the limiting dilution assay. We determined the toxic effect on progenitor cells by assaying granulocyte-macrophage colony-forming units (CFU). With a combination of MP at 10(-3) M and VP16 at 75 microM, we observed the following log reduction in tumor cell clones: HL-60, 4.695 +/- 0.001; Molt-4, 3.626 +/- 0.036; Daudi, 5.633 +/- 0.001; R10/8226, 3.052 +/- 0.544; R40/8226, 3.126 +/- 0.080. CFU recovery was 24% +/- 5%. Mixing tumor cell lines with a 20-fold excess of normal irradiated BM cells did not eliminate the inhibitory effect of the drug combination. We propose that MP and VP16 used in concert produce effective purging of malignant hematopoietic cells from BM while sparing normal progenitors needed for engraftment.

Antineoplastic Agents↗
PubMed1991

The diphosphonate space: a useful quantitative index of disease activity in patients undergoing hydroxy methylene diphosphonate (HMDP) bone imaging for Paget's disease [corrected].

Comparison between the plasma levels of intravenously injected technetium 99m hydroxy methylene [corrected] diphosphonate (99mTc-HMDP) and chromium 51 ethylene diamine tetra-acetic acid (51Cr-EDTA) reflects the uptake of diphosphonate into bone (the diphosphonate space). This can be used as an index of skeletal function in metabolic bone disease. In a series of 49 patients with Paget's disease the diphosphonate space (DPS) correlated well with other indicators of disease activity such as alkaline phosphatase and urinary hydroxyproline levels. The DPS is a good predictor of the volume of skeletal involvement as estimated from bone images. The DPS also provides a sensitive indicator of response to treatment with intravenously administered bisphosphonate. The DPS is simple to perform and is a useful adjunct to routine bone imaging.

Alkaline Phosphatase↗
PubMed1991

An evaluation of an alternative to long-stay hospital care for frail elderly patients: I. The model of care.

Recent UK government policy has advocated the development of case management to provide more coordinated care at home for vulnerable people. This paper describes a service model whereby case managers, with devolved budgets, employed by the social services department, were located in a geriatric multidisciplinary team to provide an alternative for patients requiring long-stay hospital care. As well as co-ordinating packages of care, case managers were responsible for deploying the time of home care assistants, multi-purpose workers who assisted health care staff and undertook home help tasks. The role of case managers within the multidisciplinary team is explained and the tasks undertaken by home care assistants are identified. Home care assistants undertook a wider range of activities than either home helps or nurses, covering both personal and domestic care tasks.

Aftercare↗
PubMed1991

An evaluation of an alternative to long-stay hospital care for frail elderly patients: II. Costs and effectiveness.

This paper provides the main findings of an evaluation of a service to provide alternative care at home for patients receiving long-stay hospital care. Elderly people receiving the service were compared with a group of similar patients in an adjacent health district. The paper presents data on length of time at home and in hospital, changes in quality of life and care of elderly people, and effects upon informal carers for the two groups. Elderly people receiving community-based care had a higher quality of life, and there was no evidence of greater stress upon their carers. The community-based service, although it involved extra costs to the social services department, had lower costs for the health service and society as a whole than long-stay hospital provision. It is concluded that the model of care can effectively integrate the new approach of case management into an existing geriatric multidisciplinary team.

Activities of Daily Living↗
PubMed1991

Imaging the tongue and vocal tract.

The internal structures of the vocal tract are difficult to measure without impinging upon their normal movement patterns. Imaging techniques overcome that difficulty because they measure internal movement indirectly, without direct contact with the structures. This paper examines four well-known imaging techniques: X-ray, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound. Tongue and vocal tract researchers have employed all of these techniques. Imaging systems provide very different articulatory information from flesh point tracking systems. They provide information about the shape and position of the entire imaged structure, rather than a single point on the structure. In addition, images usually can be made in multiple planes, providing midsagittal, parasagittal, coronal, transverse and oblique sections of the structure. However, these systems have several limitations. CT and MRI create static images only. Ultrasound cannot image hard tissue. Radiation exposure limits the duration of X-ray imaging. This paper discusses the advantages and limitations of imaging systems, as well as the uniqueness of the measurements made with them.

Humans↗
PubMed1991

Surgical intensive care unit resource use in a specialty referral hospital: I. Predictors of early death and cost implications.

The rationing of medical care prioritizes the need for early predictors of death in the surgical intensive care unit (SICU). We prospectively studied 100 consecutive SICU admissions, looking for predictors of early death in the SICU and the cost implications of these findings. Serial APACHE II scores on days 1, 3, and 5 were subjected to multinomial logistic regression analysis to determine significant predictors of death in the SICU on day 1. Survivors had significantly lower (p less than 0.05) mean day-1 APACHE II scores than had nonsurvivors (13.6 vs 22.1). Half of the patients with scores greater than 18 died, and all patients with scores on day 1 of 25 or greater died. Significant predictors of death on SICU day 1 were APACHE II scores, Acute Physiology Score, Glasgow Coma Score, creatinine level, and Chronic Health Evaluation Score. Forty-one patients had been transferred from community hospitals as a results of acute illness; this population accounted for two thirds of the deaths in the SICU. Ten of 18 nonsurvivors were predicted on day 1, with these patients incurring a total cost of approximately $1 million. If therapy had been modified on days 5, 10, or 15, the potential cost savings would have been $340,000, $240,000, or $140,000, respectively. Integration of the results of this study into the management decision-making process and treatment guidelines may reduce the cost of care in the SICU.

Costs and Cost Analysis↗
PubMed1990

Effects of transplantation on the primitive immunohematopoietic stem cell.

Transplantation has strong deleterious effects on the primitive immunohematopoietic stem cells (PSC) from which circulating lymphocytes and erythrocytes are descended. We studied these effects over 300-400 d, testing whether PSC numbers, repopulating abilities, or both, were reduced. Equivalent PSC numbers were estimated in recipients of mixtures of genetically different cells, using the binomial model with covariance. Percentages of lymphocyte and erythrocyte types were closely correlated, as were percentages of either type sampled at intervals of several months. This suggests that the same PSC produced lymphoid and myeloid cells, and that most circulating cells were descended from the same PSC over hundreds of days. Equivalent PSC concentrations were approximately 1/10(5) fresh marrow cells, and were about twofold lower using previously transplanted marrow. However, such marrow repopulated only one-seventh to one-eighth as well as fresh marrow. Apparently, transplantation not only reduces PSC concentrations, but also reduces the repopulating ability per PSC. This may result from excessive stimuli to differentiate that overbalance the stimuli for PSC to replenish themselves.

Analysis of Variance↗
PubMed1990

A stratified binomial marker model for bone-marrow repopulation experiments.

The paper considers bone-marrow repopulation experiments with injected mixtures of two types, A and B, of genetically marked donor cells. The covariance of the proportions of type A erythrocytes and lymphocytes is analysed as the sum of two components, under a stratified binomial model allowing the proportions of type A cells to vary in postulated strata of the mixture and with the assumption that the genetic marker does not influence cell development. The ratio of the two components is not experimentally estimable, but each of them has an interesting "demographic" interpretation. Possible inferences about certain "two-cell probabilities" are derived, and the experimental findings that necessitated the stratified model are illustrated.

Animals↗
PubMed1990

Surgical intervention in children with human immunodeficiency virus infection.

Twenty-one children with human immunodeficiency virus (HIV) infection required surgical intervention during the course of their disease. There were 11 females and 10 males (age range, 3 months to 6 years). The children underwent 54 operative procedures after diagnosis of their disease. These included placement of central venous catheter (23 patients), open lung biopsy (11), incision and drainage of perirectal abscess (4), incision and drainage of soft tissue abscess (5), myringotomy (2), diverting colostomy (3), Nissen fundoplication (1), and other (5). All 21 patients had clinical AIDS by the Centers for Disease Control CDC classification. To date, there have been 12 deaths in the 21 patients (57%) due to progressive deterioration with the patient's disease. Most procedures were adjuncts for diagnostic and therapeutic intervention in a population of children with a uniformly fatal disease. The knowledge of various high risk groups for AIDS must heighten the surgeon's awareness to the growing and significant pediatric segment of the HIV population, the complications of their disease, and the surgeon's limited role in treating these problems.

Acquired Immunodeficiency Syndrome↗
PubMed1990

A three-dimensional model of tongue movement based on ultrasound and x-ray microbeam data.

Point-tracking techniques provide timing information about structural movements of the tongue. Imaging techniques provide information about cross-sectional and pharyngeal tongue shape and movement. This study joined these techniques in a single subject. Five pellets on the tongue surface were tracked using x-ray microbeam, and the midsagittal and coronal planes of the tongue were imaged using real-time ultrasound. The speech materials were the consonants [s] and [l] and the vowels [i], [a], and [o] combined in VCVCe utterances. Analyses concentrated on the difference in tongue movements related to the two consonants. A model of tongue movement was developed, in which critical features of consonant shape and position dominated the tongue opening movement. In this model, the tongue is divided into subdivisions termed "functional segments" in both the sagittal and coronal planes. Movements of the functional segments created observable opening movement patterns.

Humans↗
PubMed1989

Numbers and functions of transplantable primitive immunohematopoietic stem cells. Effects of age.

This report introduces a new method in immunology, a use of the binomial formula with covariance to estimate numbers and proliferative patterns of the most primitive lymphoid precursors. We studied the primitive stem cells (PSC) from which most circulating lymphocytes and erythrocytes were descended during 300 to 400 days in recipients of genetically distinguishable marrow mixtures in competitive repopulation. Equivalent PSC concentrations (Eq. PSC Conc. or Conc.) were estimated, with the notion of common PSCs contributing equally in lymphoid and myeloid compartments. Similar estimation was done for common PSCs from which lymphocytes (and erythrocytes) drawn at successive sampling times about 100 days apart were descended. The percentages of lymphocyte and erythrocyte types, P1 and Pe, measured in each recipient were closely correlated, especially after 6 months and later. Close correlations were also found in cells sampled at successive one hundred day intervals, especially after the first. Apparently a few PSCs or their direct descendents produced most of the blood lymphocytes and E, and this production continued for many months. Concentrations of these PSCs (Equivalent PSC concentrations) were about one per 10(5) marrow cells from young donors. This is much lower than previous estimates, probably because our methods focus only on the most interesting precursors, those from which most of the circulating cells were descended. Equivalent PSC concentrations were about two-fold higher in old donors; old marrow produced correspondingly higher P1 and Pe values, but these declined with time. There were also small increases with time in the P1 and Pe values with young donors. To explain the temporal trends, we suggest that excess concentrations of precursors less primitive than PSC are present in old marrow, and their contribution to the differentiated cell population gradually declines. Possibly such precursors, as well as true PSC, proliferate in old donors to compensate for deficiencies that develop with age.

Aging↗
PubMed1989

Isobolic determination of "ratio-linear" parameters in pharmacological stimulus-response models.

Two response models of fundamental importance in pharmacology are introduced, which are partly-specified functions of experimental variables, unknown parameters and random disturbances. An analysis is carried out of the extent of determination of the parameters from knowledge of isobol structure alone, with results that are more powerful than might have been expected. Moreover, such knowledge is exhaustive, unless untestable assumptions are admitted. The paper is not concerned with statistical methods for estimating the determined parameters.

Linear Models↗