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Biomedical subjects

K Andrews

Publications and source records attributed to K Andrews.

At least 73 records · Page 4Linked to original sources
PubMed1990

Intraperitoneal administration of carrier erythrocytes in dogs: an improved method for delivery of L-asparaginase.

Carrier erythrocytes were prepared to encapsulate L-asparaginase by a hypotonic dialysis process. Dogs received either intravenous or intraperitoneal injections of cells containing both L-asparaginase and the marker [3H]inulin. The route of administration had no effect on the circulating survival of carrier erythrocytes. For enzyme therapy, intraperitoneal injection of a large volume of cells is technically feasible. Cells circulate with a maximum of 30% of the cells reaching circulation 24 h after injection. Those cells reaching circulation have a 7-day half-life for the encapsulated enzyme L-asparaginase.

Animals↗
PubMed1989

A study of staffing levels in hospital wards for severely physically disabled patients.

This paper reports on an investigation of the workloads of the different grades of nursing staff caring for severely physically disabled patients in a long-term rehabilitation hospital. Results of nurse activity sampling and assessment of patients' severities of disability on three wards are presented in the form of tables and bar-charts. Wide variation of types and severities of patients' disability within and between the three wards was evident. Qualitative trends relating patients' severities of disability to times spent feeding patients, total nursing hours per patient (12-hr) day, and trained/untrained staff ratios were revealed. The question of grade mix is briefly discussed.

Activities of Daily Living↗
PubMed1989

Absorbed radiation by various tissues during simulated endodontic radiography.

The amount of absorbed radiation by various organs was determined by placing lithium fluoride thermoluminescent chip dosimeters at selected anatomical sites in and on a human-like X-ray phantom and exposing them to radiation at 70- and 90-kV X-ray peaks during simulated endodontic radiography. The mean exposure dose was determined for each anatomical site. The results show that endodontic X-ray doses received by patients are low when compared with other radiographic procedures.

Dental Pulp Cavity↗
PubMed1988

Determination of parameters for enzyme therapy using L-asparaginase entrapped in canine erythrocytes.

The antitumor agent L-asparaginase was entrapped in canine erythrocytes by a single dialysis encapsulation (efficiency mean = 30%). Concentration of asparaginase in carrier cells was about 240 IU/ml, with an average of 62% cell recovery. Use of a double dialysis procedure increased the L-asparaginase concentration within carrier cells to 530 IU/ml, with an overall cell recovery of 53.9%. In vitro efflux experiments showed L-asparaginase-loaded canine carriers were stable at both 4 and 37 degrees C for an 18-h period. In vivo cell survival studies showed that carrier cells did circulate and that L-asparaginase had a half-life of 6.5 days. No evidence suggesting that the enzyme left the cell was found. Carrier cells prepared with [3H]inulin and [14C]sucrose were stored at 4 degrees C for 2 weeks and began to show signs of deterioration after 2 days.

Animals↗
PubMed1988

Encapsulation of interleukin-2 in murine erythrocytes and subsequent deposition in mice receiving a subcutaneous injection.

Radiolabeled recombinant human interleukin-2 (IL-2) was successfully encapsulated in both mouse and sheep erythrocytes. Of the added IL-2, 70% was recovered bound to or encapsulated within the carrier cells. Erythrocytes containing IL-2 were stable in vitro and most of the IL-2 remained associated with the cells following a 16-h incubation at 37 degrees C. When carrier erythrocytes containing IL-2 were injected subcutaneously into mice, intact [35S]IL-2 was detectable in a number of tissues 3 days after injection.

Animals↗
PubMed1988

Targeting of mycotoxins to reticuloendothelial system of mice with carrier erythrocytes.

The tricothecene mycotoxin, T-2 toxin, was encapsulated in bovine erythrocytes for in vivo delivery of T-2 toxin to macrophages. Intraperitoneal injection of bovine carrier erythrocytes (5 X 10(8) cells) containing T-2 toxin saturated mouse liver uptake of erythrocytes by 6 h postinjection. At 24 h postinjection, 20% of the injected carrier cells containing toxin were localized in the liver of mice. Saturation of the liver uptake of bovine carrier cells was independent of encapsulated or free T-2 toxin. A dose of T-2 toxin sufficient to inhibit 50% of the macrophage protein synthesis was targeted to the liver via the carrier erythrocytes. A methodology for delivery of highly toxic molecules to liver macrophages is described.

Animals↗
PubMed1987

Interaction of T-2 toxin with bovine carrier erythrocytes: effects on cell lysis, permeability, and entrapment.

Hemolysis, morphological changes, binding, and effect on encapsulation of exogenous substances were used as a basis to study the interaction of the trichothecene mycotoxin, T-2 toxin, with erythrocytes. T-2 toxin did not cause hemolysis of bovine erythrocytes but readily hemolyzed rat erythrocytes. T-2 toxin interaction with bovine erythrocytes was minimal because T-2 toxin did not bind appreciably to the erythrocytes. Entrapment of T-2 toxin in carrier erythrocytes was independent of toxin concentration, and interaction of T-2 toxin with erythrocytes did not affect the entrapment of the markers sucrose or inulin. T-2 toxin rapidly diffuses from carrier erythrocytes with less than 20% remaining after 4 hr of incubation. Cross-linking of the erythrocyte membrane with glutaraldehyde prevents T-2 toxin efflux from carrier erythrocytes.

Animals↗
PubMed1987

'Silent' pyrexia in the elderly.

Simultaneous oral, rectal and axillary temperatures were measured in 73 elderly patients on a geriatric unit. Axillary and oral temperatures were significantly lower than rectal readings. If oral or axillary temperatures alone had been measured, pyrexia would have been missed in two thirds of patients with a rectal temperature of 37.5 degrees C or more, and about three quarters of those with a rectal temperature of 38 degrees C or more. These findings suggest that oral or axillary temperature measurements are inadequate screening tests for pyrexia in the elderly.

Aged↗
PubMed1987

Carrier erythrocytes from cattle can be prepared from cells stored in a hypotonic, porous, dialyzed state.

Hypotonic dialysis of bovine erythrocytes to 160-180 mosmol/kg produces cells with metastable pores. Cells stored for 3 weeks in a hypotonic dialyzed state can be used to prepare carrier erythrocytes. Pores generated by nonlytic hypotonic conditions are initially greater than 40 A in radius but shrink to less than 20 A with storage beyond 1 week. A metastable pore allows for hemoglobin isolation from hypotonically dialyzed cells.

Animals↗
PubMed1987

Processes of adolescent socialization by parents and peers.

Basic processes of socialization by parents and peers involving modeling and social reinforcement, in their direct, indirect, and contingent manifestations, are investigated with respect to adolescent use of alcohol and marijuana. Four causal models are tested for frequency of alcohol and of marijuana use and for initiation into alcohol and into marijuana. The analyses are based on cross-sectional and short-term longitudinal samples of adolescent-parent-best schoolfriend triads. The basic socialization processes are found to vary depending upon the source of influence, the specific drug, and the phases of behavior engaged in by the adolescent. Implications of the results for socialization theory are discussed.

Adolescent↗
PubMed1986

The role of chest radiography in the evaluation of the 'geriatric giants'.

Three hundred and eighty admissions to a geriatric assessment unit had a routine chest radiograph. Forty-four per cent presented atypically with one or more of Isaacs' 'geriatric giants'--falls, immobility, incontinence or deteriorating mental function. The chest radiograph was abnormal in 164 (44%), of whom 57 had no classical clinical cardiopulmonary features. The chest radiograph was especially useful in the investigation of the geriatric giants, where 22% had evidence of cardiopulmonary disease, in the absence of classical clinical features.

Aged↗
PubMed1986

The impact of leukemia status at the time of HLA-identical sibling marrow transplantation on subsequent complication rate and survival of adults with acute leukemia.

Between March 1981 and March 1985, 76 patients with acute leukemia were treated with cyclophosphamide (120 mg/kg), 12 or 14 Gy total body irradiation, and an HLA-identical sibling marrow transplant. Forty-seven patients had acute non-lymphoblastic leukemia (ANLL) and 29 had acute lymphoblastic leukemia (ALL). Forty-one were transplanted during first remission and 28 during or after first relapse of their disease. An additional six patients were transplanted because their leukemia was refractory to conventional cytotoxic chemotherapy, and one was transplanted as initial therapy. Actuarial 42 month survival for those transplanted during first remission was 47% and for those transplanted in first relapse or later it was 22% (p = 0.02). There was no difference in either group between those with ANLL and those with ALL. Two of the six patients with refractory leukemia are alive more than 22 and more than 15 months after the transplant. The incidence of acute graft-versus-host disease and interstitial pneumonitis was 90% and 39%, respectively, for the first remission group, and 96% and 37% for those transplanted in first relapse or later. There was no significant difference in transplant-related mortality between the two groups (29% and 43%, respectively). The leukemia recurrence rate, however, was 13% for those transplanted in first remission and 67% for those transplanted in first relapse or later (p = 0.0003). Thus, the major factor determining the incidence of leukemia recurrence and survival after transplant was the status of the leukemia at the time of transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1986

Relevance of readmission of elderly patients discharged from a geriatric unit.

Eight percent of the elderly patients discharged from a geriatric unit in one year were readmitted within three months. Forty-six percent had been living alone and nearly all of these had received full community support at the time of discharge. Recurrent problems were the reason for readmission in 59% of cases, mainly due to falls, incontinence, and confusion. Only 54% of the readmitted patients were discharged home again--those with new additional problems tended to die in hospital, whereas those with recurrent problems often required institutional long-term care. It is concluded that even with careful discharge planning, a proportion of patients will require readmission, some of which will also require long-term institutional care. This number is quite small in terms of the total number of patients discharged from a geriatric unit and should not be a reason for seeking nursing home care at an early stage.

Accidents↗
PubMed1986

Stability of membrane pores in hypotonically dialyzed erythrocytes: coencapsulation of different stokes radius probes can occur for at least 21 days in human erythrocytes.

Hypotonic dialysis of human erythrocytes results in porous cell stability for several days. Hypotonic cells stored for 1 week are essentially normal with respect to the preparation of carrier erythrocytes. Afterward, cells begin to irreversibly hemolyze resulting in decreased cell recoveries and decreased encapsulation percentages of two probes, sucrose and inulin. The holes generated by controlled hypotonic dialysis (100 mOsm/kg) are unlike the single rupture hole generated by dialysis to 10-20 mOsm/kg. The minimum pore size of resealed, annealed carrier cells is confirmed to be less than 5.2 A.

Blood Preservation↗
PubMed1986

Membrane pores in hypotonically dialyzed sheep erythrocytes remain open after three weeks of storage: entrapment of different stokes radius probes, [14C]sucrose and [3H]inulin.

Sheep carrier erythrocytes were prepared from dialyzed cells stored for 3 weeks. The initial pore size in freshly dialyzed cells exceeds the Stokes radius of that for hemoglobin. Hypotonically dialyzed erythrocytes are then very stable in a porous state. Two probes of different Stokes radius were used to determine the relative size of the pores. Sheep erythrocytes entrap inulin to a greater extent than sucrose, a much smaller molecule. With storage, a greater fraction of dialyzed cells become impermeable to inulin than to sucrose indicative of pore size greater than 5.2 less than 20 A. Since hemoglobin content did not change relative to storage, the pore size was less than the Stokes radius of hemoglobin. Pores generated by controlled hypotonic dialysis are unlike the single rupture pore found in erythrocyte ghosts.

Animals↗