Granulocytic-monocytic colony-forming activity of marrow cells was evaluated at presentation in 20 patients with acute nonlymphocytic leukemia (ANLL). A double-layer agar culture was employed to determine colony- and cluster-forming activity. All patients underwent induction chemotherapy with cytosine arabinoside and daunorubicin. Five patients died during induction. Eight of the 11 patients entering complete remission had absent or decreased colony and cluster growth of marrow cells. Four patients who failed to obtain a complete remission produced increased or only cluster growth in culture. Our data support the conclusions of others that decreased colony and cluster formation in vitro is associated with a more favorable response to induction chemotherapy for ANLL.

Acute Disease↗

PubMedDate not supplied

Database design for an archive of animal sounds.

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Animals↗

PubMedDate not supplied

Alopecia areata.

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Adolescent↗

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Re-examination of the effects of periodic and aperiodic stimulation on the auditory-evoked vertex response.

It has been hypothesized that aperiodic stimulation will produce larger auditory-evoked vertex responses than periodic stimulation. Attentiveness toward an acoustic stimulus by human subjects has been shown in the past to enhance the auditory-evoked response. The unpredictability of aperiodic intersignal intervals has been assumed by previous investigators to produce more attentive listening behaviour and has therefore been used clinically to obtain 'enhanced' evoked responses. In order to examine this question further, auditory-evoked vertex responses were obtained with variable-interval (aperiodic) and with fixed-interval (periodic) schedules of stimulus presentation that had geometric mean intersignal intervals of 5 or 10 s. The evoked responses were obtained from normally-hearing adults while they were engaged in a counting task and while they were reading. Tone bursts were presented at 30 and 60 dB sensation level. No significant differences in peak-to-peak amplitude measures of components with latencies shorter than 300 ms could be attributed to aperiodic stimulation. When the time-base on the signal averager was extended to include components with latencies longer than 300 ms, no significant changes in component amplitudes could be attibuted to aperiodic stimulation, even though peak-to peak amplitudes during an attentive state (counting) were nearly double those obtained during an inattentive state (reading). It was concluded that aperiodicity in intersignal intervals is not a useful technique to employ in order to produce larger and more identifiable evoked responses for clinical diagnosis.

Acoustic Stimulation↗

PubMedDate not supplied

Thermal effects of acrylic cementation at bone tumour sites.

The use of acrylic bone cement as an adjunct to surgical excision of giant cell tumour of bone appears to reduce the incidence of tumour recurrence. Possible mechanisms for this apparent tumour inhibition include cytotoxic effects from the methylmethacrylate monomer and tissue hyperthermia from the heat of polymerization of the cement. This work presents a method for the prediction of temperature fields and resulting tissue necrosis arising from the implantation of polymethylmethacrylate (PMMA) at the site of a curretted giant cell tumour of bone. This is accomplished using a two-dimensional model based on geometry obtained from digitized MRI images of the distal femur. A general-coordinate, non-orthogonal grid generation technique is used and solutions are obtained with an alternating-direction implicit (ADI) finite-difference scheme. The nodal temperature histories are then used to evaluate the effect of variable defect size on the zone of thermally induced cell necrosis. The results suggest the depth of the necrotic region is quite sensitive to the size of the implant. In at least some cases, the heating effect is sufficient to cause significant necrosis of tumorigenic cells. Implanting a large mass of acrylic may risk overkill, damaging substantial amounts of healthy tissue.

Bone Cements↗

PubMedDate not supplied

Comparison of platelet glass bead retention techniques in patients with clinical bleeding disorders.

Platelet glass bead retention by the Salzman and infusion pump techniques were compared in 36 control individuals, 10 patients with von Willebrand's syndrome and four patients with thrombocytopathies. No significant differences between the results of the two assays were observed. Eleven percent or less of the control individuals had diminished platelet glass bead retention. The mean percentage platelet retention of the von Willebrand's group and the thrombocytopathy group was less than the mean platelet retention of the control group. However, at least 50 percent of the patients with von Willebrand's syndrome had normal platelet retention by both methods. In the thrombocytopathy group, glass bead retention was more consistently diminished. Although an inverse correlation existed between the duration of bleeding time and the platelet retention assays, consistently diminished platelet retention results were observed only when the bleeding time was 18 minutes or longer. It has been concluded by us that while the glass bead retention assays may be helpful in characterizing certain types of platelet disorders, they are not useful screening assays in the diagnosis of von Willebrand's syndrome.

Blood Coagulation Disorders↗

PubMedDate not supplied

Acute leukemia presenting with myeloid and lymphoid cell markers.

A case is described of acute leukemia whose neoplastic cells possessed myeloid and lymphoid characteristics. Neoplastic cells possessed cytoplasmic granules containing Sudan black B material and diaminobenzidine myeloperoxidase. In addition, these luekemic cells were positive for terminal deoxynucleotidyl transferase. Ia antigen, and the common acute lymphocytic leukemia antigen. These findings indicate that biphenotypic cell markers may exist in cases of acute leukemia. It is our belief that these results are best explained as either a mixed myeloid-lymphoid leukemia or a stem cell leukemia capable of differentiating into myeloid and lymphoid cells.

3,3'-Diaminobenzidine↗

PubMedDate not supplied

[Left-sided delivery position according to Simm's method].

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Delivery, Obstetric↗