Search PubMed⌕ Search

Biomedical subjects

C F Arkin

Publications and source records attributed to C F Arkin.

36 records · Page 2Linked to original sources
PubMed1987

The white blood cell differential. Evaluation of rapid impression scanning versus the routine manual count.

A quick, one and a half-minute qualitative microscopic scan was investigated as an alternative approach to the more labor-intensive 100-cell differential white blood cell count. The scanning results of 400 randomly selected hospital cases were compared with the on-line results of the 100-cell counts. Additionally, 50 cases selected to have a high percentage of abnormal results were each scanned and manually counted by four different readers. The results indicate that the scanning differential is equivalent to the 100-cell manual count in the detection of the presence of abnormal cell types such as immature granulocytes and blasts. Its ability to properly estimate the relative proportions of normal cells, especially lymphocytes, however, does not appear as reliable as the manual count. Most importantly, the analysis demonstrates that the scanning differential count exhibits a set of advantages and disadvantages that is complementary to those of the "three-part differential" technic provided by the newer generation automated hematologic analyzers. The authors therefore propose that these two procedures used in combination offer a suitable alternative to the manual 100-cell differential count.

Basophils↗
PubMed1987

The effects of heparin on the activated partial thromboplastin time of the College of American Pathologists Survey specimens. Responsiveness, precision, and sample effects.

Heparinized survey samples from the College of American Pathologists from 1981 through 1984 were reviewed to assess effects of the various reagents and instrumentation on the performance of the activated partial thromboplastin time (aPTT) in response to heparin. Responsiveness of the aPTT to the concentration of heparin as well as its sensitivity to the detection of heparin in the therapeutic range was most affected by choice of reagents. Precision was most affected by choice of instruments with photo-optical devices being roughly comparable. A previously described effect of calcium vs sodium salts of heparin was not supported by these data. Survey results were compared with results from fresh plasma samples from patients who had received heparin therapeutically and with response curves obtained from specimens heparinized ex vivo. The pattern of reagent dose responsiveness to the heparinized patient samples differed from that seen with survey samples and with the ex vivo heparinized fresh plasma samples. In addition, intrinsic characteristics of the individual specimens exerted substantial effects on the test results for all specimen types. Therefore, one cannot automatically assume that phenomena that hold for one form of plasma preparation are applicable to another. The nature and source of the heparinized plasma specimen must be taken into account when interpreting aPTT results.

Blood Coagulation Tests↗
PubMed1987

Etoposide in combination with cytarabine, doxorubicin, and 6-thioguanine for treatment of acute nonlymphoblastic leukemia in a protocol adjusted for age.

Etoposide combined with cytarabine, doxorubicin, and 6-thioguanine was used to treat 34 patients with acute nonlymphoblastic leukemia (ANLL) in an age-adjusted protocol, with patients greater than 50 years old receiving fewer days of therapy. Complete remissions (CR) occurred in 85% of all patients (29 of 34 patients). Patients less than or equal to 50 years of age achieved a 94% CR rate (17 of 18 patients) compared to a 75% CR rate (12 of 16 patients) in older patients. Duration of remission was less for those greater than 50 years of age. The remission rate for primary ANLL was 86% (19 of 22 patients) and for secondary or relapsed ANLL was 83% (ten of 12 patients). Thus, this is effective therapy for primary and secondary or relapsed ANLL. When the days of therapy are reduced for older patients' age, the remissions are fewer and less durable.

Acute Disease↗
PubMed1985

Quality control: what are our goals? How much is necessary?

Can laboratories modify their quality control procedures to reduce costs without affecting the quality of patient care? In discussing some approaches to modification, the author focuses on the quality control of batch analyses and methods comparison studies.

Hospital Departments↗
PubMed1985

Giant invasive cholesteatoma. Report of a case with cerebellar invasion.

We present a case of epidermoid cholesteatoma that killed the patient by relentless invasion, despite radical surgery. An autopsy disclosed a focus of dural and cerebellar invasion, which dramatized the aggressive nature of this disease. In fact, the epithelial cells of this disease are not thought to possess the ability to invade. Instead, inflammation is believed to both stimulate the squamous epithelial cells to proliferate and destroy adjacent tissues, thereby providing a pathway for epithelial cell migration. Epidermoid cholesteatoma, then, is a disease in which the processes of inflammation and hyperplasia combine to mimic a neoplasm.

Bone Diseases↗
PubMed1985

Stability of cimetidine hydrochloride in a total nutrient admixture.

The stability of cimetidine hydrochloride in a total nutrient admixture was studied. A total nutrient admixture composed of 5% amino acid injection, 20% dextrose injection, and 3% intravenous fat emulsion was prepared aseptically in four 2-L ethylene-vinyl acetate bags. Cimetidine hydrochloride injection was added to three of the admixtures to yield final cimetidine concentrations of 600, 1200, and 1800 mg per 1500 mL of admixture; the fourth admixture served as a control. At 0, 24, and 48 hours, cimetidine content was measured by high-performance liquid chromatography, and the admixtures were tested for pH and visually inspected for signs of creaming, oiling out, or phase separation. Particle-size distribution in the admixtures was compared with that in 20% intravenous fat emulsion. No appreciable changes in cimetidine concentration or pH occurred over 48 hours, and no visual changes were observed. Particle sizes were comparable to those in the 20% intravenous fat emulsion control except in the admixture containing cimetidine hydrochloride 600 mg, which had significantly more particles larger than 9.9 microns at 48 hours. In the total nutrient admixture studied, cimetidine hydrochloride in concentrations up to 1800 mg per 1500 mL was stable for 24 hours at room temperature, and the lipid emulsion was apparently not altered during this period by cimetidine.

Chromatography, High Pressure Liquid↗
PubMed1981

Acute B-cell leukemia occurring with Hodgkin's disease.

The association of lymphoid neoplasms with Hodgkin's disease is being recognized with increasing frequency. These tumors often occur concurrently with Hodgkin's disease and are not as clearly related to therapy as are other secondary tumors. Presumably, the immune deficiency state found in Hodgkin's disease plays an important role. A patient with Hodgkin's disease and simultaneous acute lymphocytic leukemia is reported. The leukemia was B cell in type, a rare form that most likely is identical to acute lymphosarcoma cell leukemia of immature cell type. This case expands the spectrum of lymphoid neoplasms known to occur with Hodgkin's disease. The fact that the leukemia responded to therapy for Hogkin's disease suggests that some lymphoproliferative disorders discovered subsequent to therapy are not the result of therapy but recurrences of previously undetected and therapeutically suppressed disease.

B-Lymphocytes↗
PubMed1981

The T-test and clinical relevance. Is your beta error showing.

The t-test, as usually performed in the clinical laboratory for methods comparisons, does not consider the clinical relevance of the difference between the methods. Two procedures are presented which incorporate medical criteria into the t-test thereby making it a more relevant statistical tool. This is done by defining beta error in addition to alpha error. Since a positive action; i.e., adoption of the "test" methods, is taken when there is no difference between the "test" and reference methods, commission of a beta error has a potentially damaging effect. Therefore, evaluation of beta error is an appropriate part of methods comparison in the clinical laboratory.

Laboratories↗
PubMed1979

The hypercoagulability states.

Although interest in coagulation has usually centered about the various hemorraghic disorders, it is hyperactivity of the hemostatic system with its thrombotic complications which has a far greater clinical impact. The hypercoagulability states are a vague group of disorders not well defined by the laboratory. They fall into two distinct groups: (1) conditions promoting venous thrombosis by activating the coagulation mechanism and (2) conditions promoting arterial thrombosis by platelet plug formation. Dealing with both of these groups separately the various disorders associated with a hypercoagulable state are discussed as well as their pathophysiologic basis; Special emphasis is placed on the laboratory evaluation of these disorders.

Blood Coagulation↗
PubMed1977

An automatic leukocyte analyzer. Validity of its results.

A statistical study was undertaken to evaluate the Corning Larc Leukocyte Analyzer by comparing its results with those of 20 medical technologists with regard to reproducibility and degree of agreement. A special effort was made to use statistically quantitative comparisons, large numbers of samples, and a large group of technologists. The results of the Larc are frequently more reproducible than those of technologists, especially for bands and segmented neutrophils. Other comparative studies show that the Larc reports clinically equivalent proportions of the different cell types normal and abnormal. This is true for case by cases as well as cumulative comparisons. All known cases of leukemia was detected by the Larc during the study, although the number of samples from leukemia patients was small (11 of 700).

Animals↗
PubMedDate not supplied

Vancomycin stability in heparin and total parenteral nutrition solutions: novel approach to therapy of central venous catheter-related infections.

To facilitate therapy of central venous catheter-related Gram-positive bacterial infection in patients who require total parenteral nutrition (TPN) therapy, we studied the stability of vancomycin in a commonly used TPN solution (V-TPN) at final concentrations of 0.5 mg/mL and 1.0 mg/mL and in heparin (100 U/mL in 0.9% NaCl) at 25 micrograms/mL (V-H). Vancomycin concentrations in V-TPN and V-H after storage at 4 degrees C over 35 and 14 days, respectively, were stable (within 10% of the prestorage vancomycin concentration). After 14 days at 4 degrees C heparin activity in V-H solution was 100 +/- 4% of that noted initially. Vancomycin remained stable (100 +/- 6% of the original vancomycin concentration) when the previously refrigerated V-TPN was held for an additional 24 hours at 22 degrees C. When the previously refrigerated V-H was held for an additional 24 hours at 37 degrees C, vancomycin concentrations decreased to 78 +/- 9% of the baseline concentrations (p less than .001). The stability of vancomycin in this TPN solution allows the daily dose of vancomycin to be mixed with the solution and then infused over 10 hours. As shown with pharmacokinetic modeling, this form of therapy will achieve serum vancomycin concentrations within the therapeutic range throughout a 24-hour period. The relative stability of vancomycin in a heparin line-flush solution allows vancomycin concentration in the lumen of the catheter to be maintained at greater than or equal to 15 micrograms/mL during the interval between catheter flushing and the subsequent TPN infusion. A simplified method of administering vancomycin to patients receiving concurrent TPN is possible.

Catheterization, Central Venous↗
PubMedDate not supplied

Response of red blood cell control materials to altered testing conditions.

While many features are regularly considered in selecting control reagents, the responsiveness of these products to methodologic errors is frequently overlooked. To address this issue with regard to commercially prepared whole blood cell controls, mean cell volume (MCV) determinations were performed on several preserved red blood cell controls and fresh blood in the presence of various artifacts. The effects contaminating the isotonic diluent with water, saline, or bleach were compared. Although our results indicate that preserved and fresh RBCs generally behave similarly, large differences were observed in the responses to hypotonic stress among controls and between controls and fresh specimens. As this may have clinical relevance, our data highlight the need for testing the responsiveness of controls to commonly encountered methodologic variables as part of the routine evaluation of these products.

Blood Preservation↗
PubMedDate not supplied

Paranuclear microfilaments in multiple myeloma associated with the presence of free light chains.

Two cases of multiple myeloma are reported showing striking arrays of paranuclear microfilaments confirming a previous single case report done on autopsy material. Both cases showed free light chains in the urine. In one case, free light chains were in the serum, and there was some evidence of polymer formation. Although this suggests that the microfilaments are polymerized light chains, amyloid strains were negative. Whatever their origin, the structures are clearly abnormal and may serve as a neoplastic marker.

Aged↗