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Biomedical subjects

R Hill

Publications and source records attributed to R Hill.

At least 181 records · Page 10Linked to original sources

Response to memory training and individual differences in verbal intelligence and state anxiety.

Prior studies have documented the effectiveness of several types of memory training for the elderly with normal age-related memory losses. Despite these positive results, there is substantial variability of individual response to treatment. The authors describe attributes of individuals most likely to benefit from two types of memory training. They found that for 40 elderly volunteers performance on the WAIS vocabulary subscale correlated with response to a treatment combining mnemonics and verbal elaboration techniques and scores on the Spielberger State-Trait Anxiety Inventory correlated with response to a treatment combining mnemonics and relaxation techniques.

Aged↗

A gene with sequence similarity to Drosophila engrailed is expressed during the development of the neural tube and vertebrae in the mouse.

The mouse genes En-1 and En-2 display sequence similarity, in and around the homeobox region, to the engrailed family in Drosophila. This paper describes their pattern of expression in the 12.5-day mouse embryo as determined by in situ hybridization. En-2 is expressed in a subset of cells expressing En-1. Both genes are expressed in the developing midbrain and its junction with the hindbrain. In addition, En-1 is expressed in the floor of the hindbrain, a restricted ventrolateral segment of the neural tube throughout the trunk and anterior part of the tail, the dermatome of tail somites, the centrum and costal processes in developing vertebrae, a restricted region of facial mesenchyme and the limb-bud ectoderm. Supplementary studies of 9.5-day and 10.5-day embryos showed that the same pattern of expression pertained in the neural tube, but that expression in the somites is at first confined to the dermatome and later found at a low level in restricted sclerotomal regions. Both genes are expressed in restricted domains which do not cross tissue-type boundaries. In several instances, however, boundaries of expression lie within morphologically undifferentiated tissue. These results suggest that En-1 and En-2 may be involved in the establishment or maintenance of the spatial integrity of specific domains within developing tissues.

Animals↗

Use of recombinant human granulocyte-macrophage colony-stimulating factor in autologous marrow transplantation for lymphoid malignancies.

The use of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) following autologous marrow transplantation for lymphoid malignancies was explored in a phase I/II dose escalation study. rhGM-CSF given as a 2-hour infusion daily for 14 days was well tolerated at doses up to 240 micrograms/m2/day. When compared with 86 disease-matched and treatment-matched historical controls, patients receiving greater than or equal to 60 micrograms/m2/day rhGM-CSF recovered neutrophil and platelet counts more rapidly, had fewer days with fever, and were discharged from the hospital sooner.

Blood Platelets↗

Cytogenetic evaluation of human endothelial cell cultures.

Cytogenetic evaluation of serially subcultivated human endothelial cells revealed significant differences between cultures derived from fetal umbilical cords and cultures derived from various vessel sites in adults. A rapid increase in the prevalence of polyploid cells, to levels of 100% in many cases, was detected in human umbilical vein endothelial cell cultures but not in endothelial cell cultures from adult vessels. Because the development of polyploidy has been viewed as one signpost of in vitro senescence, it may be that these in vitro observations of high levels of polyploidy are a reflection of the fact that umbilical tissue is at the end of its in vivo developmental lifespan when studied. Consistent karyotypic alterations also were observed in two clones from adult human abdominal aorta, even though these cultures exhibited low percentages of polyploid cells. Cultures of one clone exhibited a trisomy of chromosome 11, on which there are at least three onc gene loci, and a deletion of chromosome 13 through band q14. A loss of band 13q14 is a prezygotic chromosomal lesion known to predispose to retinoblastoma. In the other clone, two cell populations were observed, and each displayed a chromosomal abnormality. A trisomy of the long arm of chromosome 2 was noted in one cell population via a marker chromosome involving 2 and 14. The other cell population exhibited an abnormality of chromosome 2. Neither of these karyotypic alterations was detected in the parent culture from which the clones were derived. The results reported in this study have both practical and theoretical implications. The high incidence of polyploidy in serially cultivated umbilical cultures as well as the occurrence of chromosomal changes in umbilical and aortic cultures testify to the need for cytogenetic monitoring of cell cultures even though they are derived from presumably normal tissue. Cytogenetic changes in the endothelium may be important in atherogenesis and other pathologic states. The conversion of diploid endothelial cells into polyploid endothelial cells may provide a convenient model cell system for studying mechanisms of the development of polyploidy in cells and their relationship to in vitro senescence.

Adult↗

Effects of sodium intake during two parities on Na status in blackface sheep.

A low-sodium diet was given to Blackface ewes over two reproductive seasons. This diet provided a total of 3-7 mmol/d except during lactation when the intake was about 11 mmol/d. Control ewes were given the same diet supplemented with sodium chloride to provide recommended levels which were about tenfold that of the experimental diet. The output of Na in urine and faeces from ewes given the low-Na diet was very low, about 3 mmol/d, from early in the experiment and continued at about this level throughout. Lambs born to low-Na ewes and given a low-Na diet similar to that of their dams during lactation, grew, after weaning, more slowly than corresponding lambs from control ewes, but at 6 months of age when six from each group were killed, tissue Na contents were only slightly lower in experimental than control lambs. Fluids and tissues obtained at the end of the second lactation from four ewes of each group that had suckled twin lambs, were analysed for Na and potassium. The Na concentration in saliva and rumen fluid of low-Na ewes was about half that of control ewes and there were corresponding increases in K: the differences were significant. Although Na concentrations for experimental ewes were generally lower than those for control ewes in the tissues analysed (liver, kidney, heart, brain and bone), the difference was significant only for the heart (P less than 0.05). Haemoglobin and packed cell volume were significantly elevated in low-Na ewes (P less than 0.01), indicating decreased body fluid volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

The hemodynamic effects of sotalol and quinidine: analysis by use of rest and exercise gated radionuclide angiography.

This placebo-controlled, double-blind trial compared the hemodynamic effects of sotalol and quinidine with the use of rest and exercise gated radionuclide angiography. Patients had frequent ventricular premature depolarizations (greater than or equal to 30 VPDs/hour) and depressed cardiac function (mean ejection fraction 43 +/- 15%). Resting left ventricular ejection fraction and stroke volume index increased (p less than .002, p less than .001, respectively) during sotalol therapy, associated with a concomitant fall in heart rate (p less than .001). Quinidine also increased mean left ventricular ejection fraction, but less so than did sotalol (p less than .05). Quinidine significantly decreased left ventricular end-diastolic (p less than .05) and end-systolic (p less than .002) volumes, but had no effect on stroke volume index or heart rate. Neither drug affected cardiac index. Quinidine resulted in no symptomatic deterioration in left ventricular function or serious arrhythmia aggravation. In contrast, five patients on sotalol developed either decompensated congestive heart failure (two patients), arrhythmia aggravation (two patients), or hypotension associated with bradyarrhythmia (one patient). These patients had a unique hemodynamic profile that can be used to identify patients likely to have a poor outcome on sotalol. This profile reflected a lack of cardiac reserve, characterized by an inability to increase stroke volume and cardiac output with supine bicycle exercise.

Aged↗

Treatment of malignant lymphoma in 100 patients with chemotherapy, total body irradiation, and marrow transplantation.

Between July 1970 and January 1985, 100 patients with malignant lymphoma were treated with high-dose chemoradiotherapy and bone marrow transplantation. Twenty-eight of the 100 are alive and the actuarial probability of disease-free survival 5 years from transplantation is 22%. The most common reason for treatment failure was disease recurrence, with an actuarial probability of 60%. A proportional hazards regression analysis showed that the likelihood of disease-free survival was less in those patients transplanted in resistant relapse and in those previously treated with chest radiotherapy. Neither disease histology (Hodgkin's disease, high-grade lymphoma or intermediate-grade lymphoma), nor source of marrow (syngeneic, allogeneic, or autologous) significantly influenced either disease-free survival or probability of relapse. The use of high-dose chemoradiotherapy and marrow transplantation appears to offer a better chance for long-term survival than any other form of therapy for young patients with disseminated malignant lymphoma whose disease has progressed after initial combination chemotherapy. The best results with marrow transplantation were obtained in patients transplanted in early relapse or second remission who had not received prior chest radiotherapy.

Adolescent↗

Preparation of red-blood-cell-depleted marrow for ABO-incompatible marrow transplantation by density-gradient separation using the IBM 2991 blood cell processor.

Thirty patients who had major ABO blood group incompatibility with their HLA-matched donors underwent allogeneic marrow transplantation after removal of red blood cells (RBC) from donor marrow by Ficoll-Diatrazoate (F-D) separation using the IBM 2991 blood cell processor. We selected the IBM 2991 because we were interested in obtaining information about RBC-depleted mononuclear cells for monoclonal antibody and complement incubation of marrow. The median residual marrow RBC volume was 2.6 ml (1.2% of the original volume) and marrow infusion was well tolerated in every instance. The median doses of nucleated and mononuclear cells were 8.7 X 10(7)/kg and 2.2 X 10(7)/kg recipient weight, respectively, representing median marrow total nucleated and mononuclear cell losses of 63.4% and 52.9%, respectively. The median CFU-GM loss was 52.4%. Four patients died 13-21 days after marrow infusion and were unevaluable for engraftment. One patient failed to achieve engraftment and received a second transplant on day 36 from a second donor. One patient with myelofibrosis had poor engraftment and died on day 177 with low peripheral blood counts. For evaluable patients, no significant differences were observed in the rate of recovery of peripheral blood granulocyte or platelet counts between those receiving RBC-depleted marrow or ABO-matched unprocessed marrow. However, posttransplant red cell transfusion requirements were increased and transfusion independence delayed in patients receiving RBC-depleted marrow as compared to patients receiving unprocessed marrow. We concluded that red cell depletion using the IBM 2991 was effective in removing red cell, but resulted in significant and variable hematopoietic cell losses which may have contributed to graft failure in at least one patient. Such cell losses appear to be inherent in both manual and semiautomated methods for F-D cell separation.

ABO Blood-Group System↗

Modulation of human erythrocyte shape and fatty acids by diet.

A semi-synthetic diet (Vivonex) was administered via nasogastric tube to three cystic fibrosis patients with pancreatic exocrine deficiency for 14 days to gain weight. Dietary essential fatty acids were provided as safflower oil, which constituted 1.3% of total calories. Plasma and red blood cells were analyzed for the content and composition of lipids at the start of the diet and at days 7 and 14 of the dietary period, and the results were correlated with the morphology of the cells. Feeding Vivonex to the patients led to an essential fatty acid deficiency, which was manifested in a 50% decrease in the linoleic acid content of the phosphatidylcholine of plasma and red blood cells at days 7 and 14 and in a 20% decrease in the linoleic acid content of red cell phosphatidylethanolamine at day 14. There was no significant alteration in the levels or composition of the other phospholipid classes and in the free cholesterol/phospholipid ratio. The decrease in the linoleic acid content of the erythrocytes was accompanied by a dramatic increase in the proportion of cells as echinocytes. We conclude that restricted linoleic acid availability in cystic fibrosis patients causes a change in red blood cell shape either directly by decreasing the linoleoylphosphatidylcholine content of the membrane or indirectly by affecting enzyme activity.

Adolescent↗