Biomedical subjects

D F Andrews

Publications and source records attributed to D F Andrews.

At least 37 records · Page 2Linked to original sources

PubMed1993

Complications and costs of management of acute spinal cord injury.

This study examined the complications and costs of management of patients with acute spinal cord injury (ASCI) in a regional, multidisciplinary acute spinal cord injury unit (ASCIU). Data were available to compute length of stay (LOS) on 191 of the first 220 consecutive patients managed in this unit from 1974 to 1981. Specific formulae for assessing hospital and medical costs were developed based on a systems analysis approach. The statistical analysis included multiple regression analysis for determining the effect of the principal admission characteristics of ASCI patients, the main types of complications, and the methods of management. The effects of these variables on LOS, costs per day (CPD), and costs per stay (CPS) were determined. Age at admission, sex, and cause of accident had no effect on costs. As expected, increasing severity of injury to the spinal cord and to the vertebral column caused a significant increase in the mean LOS and CPS, and increasing total trauma load resulted in a significant increase in LOS and CPS. The LOS was shorter for patients admitted sooner after trauma. Respiratory, gastrointestinal, thromboembolic and genitourinary complications and decubitus ulceration were all associated with marked increases in LOS and CPS. The annual mean CPS decreased dramatically during the period of the study from 1974-81 due mainly to a decrease in LOS. Multiple regression analysis showed that severity and level of the spinal column and spinal cord injury, and the presence of complications had the most significant effects on duration and cost of care. The study also suggests that a specialized, multidisciplinary regional unit for ASCI patients is associated with a reduction in LOS and cost of care.

Accidents↗

PubMed1992

Monozygotic twins concordant for late-onset probable Alzheimer disease with suspected Alzheimer disease in four sibs.

Probable Alzheimer disease (AD) is described in 79-year-old male twins with monozygosity confirmed by DNA examination. The first twin to be affected began to show signs of intellectual deterioration at age 70. In the other, onset was at age 72. Four of their living sibs (current age range = 75-92) are also suspected to have AD. The possible roles of genetic and environmental factors in the development of AD in this sibship are discussed.

Aged↗

PubMed1992

Sodium vanadate, a tyrosine phosphatase inhibitor, affects expression of hematopoietic growth factors and extracellular matrix RNAs in SV40-transformed human marrow stromal cells.

Protein tyrosine kinases represent a subset of proteins that mediate signal transduction between the extracellular environment and the nucleus. We have previously described a coordinated upregulation between RNA transcripts of a tyrosine kinase, c-abl, and those of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 6 (IL-6) in human marrow stromal cells (SVMSC). Moreover, an inverse relationship exists between expression of c-abl transcripts and those of extracellular matrix proteins such as type collagen I transcripts. In the present study, these inverse relationships were again seen in SVMSC when tyrosine kinase effects were enhanced by treatment of the cells with the tyrosine phosphatase inhibitor sodium orthovanadate. This suggests that tyrosine kinases are involved in the coordinate regulation of these genes.

Bone Marrow Cells↗

PubMed1992

Effect of methylxanthine derivatives on T cell activation.

In a Phase I-II trial examining the effect of prophylactic administration of pentoxifylline (PTX) on bone marrow transplant-associated morbidity, there was an apparent reduction in the incidence and severity of acute graft-versus-host disease. To determine if PTX might be directly immunosuppressive, its effects on T cell activation and proliferation were examined. PTX and several cogeners were found to directly suppress T cell proliferation in response to phytohemagglutinin, to allogeneic cells in a mixed leukocyte reaction, and to cross-linking the CD3 complex. The effects were dose-related and associated with suppression of secretion of tumor necrosis factor-alpha (TNF alpha). However, the inhibition of proliferation was not solely due to this effect since adding excess recombinant TNF alpha did not restore the proliferative response. These data suggest that PTX may be clinically useful in suppressing allogeneic reactions in bone marrow transplantation.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1991

Family with 22-derived marker chromosome and late-onset dementia of the Alzheimer type: I. Application of a new model for estimation of the risk of disease associated with the marker.

We have identified 2 sisters with probable dementia of the Alzheimer type who have an unusual 22-derived marker chromosome with a greatly elongated short arm containing 2 well-separated nucleolus organizer regions. A marker chromosome similar in appearance is uncommon in the general population. Eleven of 24 of their biological relatives were also found to have the marker. The known pedigree of this family encompasses 6 generations in 2 of which there is evidence of 10 cases of dementia of the Alzheimer type. The average age-at-onset of dementia is 65.8 +/- 5.5 years; the average age-at-death among those apparently affected is 74.9 +/- 8.3 years. A new model for the estimation of risk was applied to the family data. Persons in this family with the marker were found to be 4 times more likely to develop dementia than those without the marker, the 95% confidence interval for this risk being 1-50. The probability that the association of dementia and the marker is due to chance alone is .05 (1 in 20).

Aged↗

PubMed1991

Intramuscular desferrioxamine in patients with Alzheimer's disease.

Although epidemiological and biochemical evidence suggests that aluminium may be associated with Alzheimer's disease (AD), there is no convincing proof of a causal link for aluminium in disease progression. We have completed a two year, single-blind study to investigate whether the progression of dementia could be slowed by the trivalent ion chelator, desferrioxamine. 48 patients with probable AD were randomly assigned to receive desferrioxamine (125 mg intramuscularly twice daily, 5 days per week, for 24 months), oral placebo (lecithin), or no treatment. No significant differences in baseline measures of intelligence, memory, or speech ability existed between groups. Activities of daily living were assessed and videorecorded at 6, 12, 18, and 24 month intervals. There were no differences in the rate of deterioration of patients receiving either placebo or no treatment. Desferrioxamine treatment led to significant reduction in the rate of decline of daily living skills as assessed by both group means (p = 0.03) and variances (p less than 0.04). The mean rate of decline was twice as rapid for the no-treatment group. Appetite (n = 4) and weight (n = 1) loss were the only reported side-effects. We conclude that sustained administration of desferrioxamine may slow the clinical progression of the dementia associated with AD.

Aged↗

PubMed1991

Transforming growth factor beta expression in human marrow stromal cells.

The effects of hematopoietic cytokines on the expression of transforming growth factors (TGF beta) mRNA and the effect of TGF beta on cytokine and on a major extracellular matrix protein, collagen I, mRNA expression was studied in human marrow stromal cells. As with other cultured mesenchymal cells, stromal cells constitutively express TGF beta 1 but not TGF alpha mRNA. In simian virus 40 (SV40)-transformed stromal cells downregulation of TGF beta 1 expression was observed 2 hours after incubation with recombinant human (rh) tumor-necrosis factor alpha (TNF alpha) and 144 h after addition of rh granulocyte macrophage colony-stimulating factor (GM-CSF). Neither interleukin-1 (IL-1)beta nor IL-6 had an observable effect on TGF beta 1 mRNA expression. TGF beta upregulated collagen I mRNA expression. These data suggest that cytokines may influence TGF beta mRNA expression.

Blotting, Northern↗

PubMed1990

Absence of the c-Ha-ras codon 61 point mutation in murine solid tumors induced by subcutaneously applied 7,12-dimethylbenzanthracene.

The c-Ha-ras-1 codon 61 A----T transversion is a highly consistent finding in murine skin DMBA-initiated/TPA-promoted papillomas and carcinomas. We performed Xba I RFLP analysis on DNA from clonal cell lines derived from 11 independent papillomas and a single carcinoma derived from topically applied DMBA and compared this to RFLP on DNA from 7 clonal fibrosarcoma cell lines derived from tumors arising after subcutaneous administration of the same carcinogen. The A----T point mutation was present in all of the papillomas and carcinoma derived by the classic DMBA-TPA protocol but was absent in all of the fibrosarcomas arising after subcutaneous administration of DMBA.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1990

Effect of age at the start of iron chelation therapy on gonadal function in beta-thalassemia major.

BACKGROUND: Patients with transfusion-dependent thalassemia major tend to have abnormal growth and sexual maturation at puberty, presumably as a result of pituitary iron overload. This study was designed to determine whether chelation therapy with deferoxamine before the age of puberty would ameliorate this problem. METHODS: We examined 40 patients over 14 years of age with transfusion-dependent thalassemia major. The 19 patients in group A (mean [+/- SD] age at study, 17.0 +/- 1.5 years) had begun nightly treatment with subcutaneous deferoxamine before the age of 10 (mean age at start of treatment, 7.5 +/- 1.8 years). The 21 patients in group B (mean age, 24.1 +/- 3.8 years) had begun treatment after the age of 10 (mean age at start of treatment, 14.4 +/- 4.7 years). RESULTS: The abnormal findings were essentially confined to sexual development. The final height did not differ between groups or from the mean parental height in each group. Ninety percent of the patients in group A had normal sexual development, as compared with 38 percent of those in group B (P = 0.001). Outcomes were correlated with indexes of iron overload; the patients in group A had lower serum ferritin levels before chelation treatment (P = 0.01) and lower average serum ferritin levels during treatment (P = 0.005). CONCLUSIONS: Beginning chelation treatment with deferoxamine before the age of puberty can help children with transfusion-dependent thalassemia major to attain normal sexual maturation.

Adolescent↗

PubMed1990

Regulation of cytokine and growth factor gene expression in human bone marrow stromal cells transformed with simian virus 40.

Marrow stromal cells are thought to regulate hematopoiesis by producing colony-stimulating factors (CSFs) and other cytokines, either constitutively or in response to mediators such as interleukin-1 alpha (IL-1 alpha) or tumor necrosis factor-alpha (TNF alpha). The mechanisms by which these inflammatory cytokines induce CSF expression in stromal cells are not fully defined. In this study, we used human marrow stromal cells transformed by simian virus 40 (SV-MSCs) to study growth factor and cytokine gene regulation in response to IL-1 alpha and TNF alpha. IL-1 alpha induced significant and prolonged increases in steady-state mRNA levels for interleukin-6 (IL-6), interleukin-1 beta (IL-1 beta), granulocyte-macrophage CSF (GM-CSF), and, to a lesser extent, granulocyte-CSF (G-CSF); this induction was not dependent on new protein synthesis. Nuclear run-on analyses showed that IL-1 alpha transcriptionally activated the genes for IL-6, GM-CSF, and IL-1 beta, while TNF alpha transcriptionally induced expression of IL-6 and IL-1 beta. Furthermore, mRNA for IL-6 and IL-1 beta was dramatically superinduced by the combination of cycloheximide and TNF alpha. When SV-MSCs were cultured in semisolid medium, they formed colonies of blast-like cells that, when replated on plastic, resumed adherent growth. These "colony-derived" cell lines, unlike the parental SV-MSCs from which they were derived, constitutively expressed colony-stimulating activity and mRNA for GM-CSF, G-CSF, IL-6, and IL-1 beta. In this report, we show that the expression of IL-6 and IL-1 beta mRNA in the colony-derived cell lines was due, at least in part, to constitutive transcriptional activation of these genes (similar to the findings in IL-1 alpha- and/or TNF alpha-stimulated parental SV-MSCs). However, in contrast to the transcriptional activation of the GM-CSF gene seen in cytokine-induced parental SV-MSCs, GM-CSF transcripts accumulated in the colony-derived cell lines by a posttranscriptional mechanism.

Biological Factors↗

PubMed1990

Red cell superoxide dismutase, glutathione peroxidase and catalase in Down syndrome patients with and without manifestations of Alzheimer disease.

The activities of red blood cell enzymes that scavenge the superoxide radical and hydrogen peroxide were measured in severely to profoundly retarded adult Down syndrome (DS) patients with and without manifestations of Alzheimer disease (AD), and control individuals matched for sex, age, and time of blood sampling. Cu,Zn superoxide dismutase (SOD-1) and glutathione peroxidase (GSHPx) activities were significantly elevated (1.39-fold and 1.24-fold, respectively) in DS individuals without AD. When an adjustment was made for the SOD gene dosage effect, DS patients with AD manifestations had significantly lower SOD levels than the matched control individuals. In contrast, DS patients with and without AD had a similar elevation in GSHPx (an adaptive phenomenon). The mean catalase (CAT) activity was no different in DS and control individuals; however, in a paired regression analysis, DS patients without AD had marginally lower CAT activity than control individuals, whereas DS patients with AD had slightly but not significantly higher CAT activity. Thus, AD manifestations in this DS population are associated with changes in the red cell oxygen scavenging processes.

Adult↗

PubMed1990

Autoimmune thyroiditis associated with mild "subclinical" hypothyroidism in adults with Down syndrome: a comparison of patients with and without manifestations of Alzheimer disease.

Serum tests of thyroid function were compared in Down syndrome (DS) patients with and without manifestations of Alzheimer disease (AD). Relative to control individuals, DS patients had, overall, lower mean total T4 (P = 0.070) and T3f (P = 0.015), higher T3U (P = 0.013) and TSH (P = 0.020), no difference in free T4, and higher thyroid antithyroglobulin (ATA) (P = 0.033) and antimicrosomal autoantibody (AMA) titres (P = 0.0097). Similar trends were apparent in DS males and females, and in DS patients off all drugs. In an analysis of case/control pairs with corrections for age and sex, DS patients with AD manifestations (n = 9) had significantly lower T3 (P = 0.029) and higher AMA (P = 0.043) than paired control individuals, whereas DS patients without AD manifestations (n = 20) had significantly lower T3 (P = 0.013) but higher ATA (P = 0.0065). T3 was significantly lower in the DS patients with AD manifestations than in the unaffected (P = 0.0013). These data suggest that autoimmune thyroiditis associated with a mild "subclinical" form of hypothyroidism is common in adult DS patients and more pronounced in patients with AD manifestations than in those without. This "subclinical" hypothyroidism may contribute to cognitive deficits in ageing DS patients.

Adult↗

PubMed1990

Cloning and sequencing of the human c-abl 3' untranslated region.

The human c-abl oncogene gives rise to different mRNA transcripts which vary primarily in that they possess alternative first exons. In the present study, we present the sequence for the human c-abl 3' untranslated region (3'utr) and show that while human and murine c-abl cDNA sequences are generally homologous, human c-abl transcripts unlike the murine c-abl transcripts do not differ significantly in their 3' utrs.

Base Sequence↗

PubMed1989

Human marrow stromal cells: response to interleukin-6 (IL-6) and control of IL-6 expression.

Production of interleukin-6 (IL-6) by marrow stromal cells from human long-term marrow cultures and from stromal cells transformed with simian virus 40 was examined. As with other cultured mesenchymal cells, unstimulated stromal cells produced undetectable amounts of IL-6 mRNA when assayed by Northern blots. However, within 30 minutes after exposure of transformed marrow stromal cells to the inflammatory mediators, recombinant human interleukin-1 alpha (IL-1 alpha) or recombinant human tumor necrosis factor alpha (TNF alpha), significant increases in IL-6 expression were observed. The time course of IL-6 mRNA upregulation in transformed marrow stromal cells with IL-1 alpha and TNF alpha differed: The maximal response to TNF alpha was observed at 30 minutes whereas that to IL-1 alpha occurred at 8 hours. Although IL-6 at a concentration of 500 U/mL was inhibitory to adherent transformed marrow stromal cell proliferation, a concentration-dependent stimulation of anchorage-independent colony growth was observed when the cells were plated in semisolid medium with IL-6. The stromal cell colony-stimulating effect of IL-6 was abrogated by a neutralizing antibody to IL-6. Moreover, the heteroserum with anti-IL-6 activity and two anti-IL-6 monoclonal antibodies partially blocked autonomous and IL-1 alpha-induced colony formation, suggesting that colony formation by transformed marrow stromal cells may require IL-6. Clonal-transformed stromal cell lines were derived from the anchorage-independent stromal cell colonies. Both IL-6 mRNA and protein were constitutively produced at high levels. The addition of IL-6 to either long-term marrow culture adherent cells or transformed marrow stromal cells downregulated the expression of collagen I, a major stromal cell matrix protein. Thus, IL-6 affects proliferation of stromal cells and influences their production of extracellular matrix, suggesting that IL-6 may have indirect as well as direct influences on hematopoietic cell proliferation.

Blotting, Northern↗

PubMed1989

Human papillomavirus infection of morphologically normal cervical epithelium adjacent to squamous dysplasia and invasive carcinoma.

We have begun a systematic study of human papillomavirus (HPV) infection in colposcopically and/or morphologically normal epithelium of the uterine cervix. Paired biopsies were taken from the lesions (cervical intraepithelial neoplasia [CIN], condyloma, invasive carcinoma) and from the normal-appearing adjacent epithelium 3 to 5 mm from the edge of the lesion. Myometrium or ectocervical epithelium from patients who had undergone hysterectomy for reasons other than genital dysplasia or malignancy served as controls. One biopsy was examined histologically. DNA from the second biopsy was digested with Pst I, and the presence or absence of HPV was determined by Southern blotting using HPV-16 DNA as a probe. HPV was not detected in any of the 12 control samples. Of 30 patients with CIN and/or condyloma, five of 18 who were HPV-positive had either HPV-16 (three cases) or virus resembling HPV-31 (two cases) in the lesion and adjacent epithelium. Of seven patients with invasive carcinoma, four had HPV in the lesion and adjacent epithelium; two of these four patients had typical HPV-16. Such infection of apparently normal epithelium has major implications for our understanding of the pathogenesis, treatment, and follow-up of patients with cervical neoplasia.

Blotting, Southern↗

PubMed1989

Recombinant tumor necrosis factor alpha and interleukin 1 alpha increase expression of c-abl protooncogene mRNA in cultured human marrow stromal cells.

Analysis of protooncogene RNA expression in marrow stromal cells from long-term marrow culture demonstrated high levels of c-abl 5-, 6-, and 7-kilobase (kb) RNA transcripts. In experiments on three independently derived simian virus 40-transformed marrow stromal cell lines, the expression of these c-abl transcripts was further increased in response to recombinant tumor necrosis factor alpha (1000 units/ml) and interleukin 1 alpha (10 units/ml). Although lymphocyte-conditioned medium predominantly up-regulated the 5-kb transcript, interleukin 1 alpha primarily affected the 6-kb transcript. The up-regulation of the 5-kb c-abl message correlated with up-regulation of the granulocyte/macrophage colony-stimulating factor transcript and down-regulation of procollagen I transcripts in transformed cells. These data suggest that c-abl plays roles in the regulation of extracellular matrix expression and in the regulation of hematopoietic growth factors by stromal cells.

Blotting, Northern↗

PubMed1989

Effect of 5-azacytidine on gene expression in marrow stromal cells.

When exposed to 5-azacytidine, marrow stromal cells from active long-term marrow cultures and cell lines derived from simian virus 40-transformed stromal cells rapidly upregulated c-abl and interleukin-6 transcripts while downregulating the expression of collagen I, a major matrix protein. Similar effects occurred with interleukin-1 alpha and tumor necrosis factor alpha, although the time course was considerably prolonged.

Azacitidine↗

PubMed1989

Response of simian virus 40 (SV40)-transformed, cultured human marrow stromal cells to hematopoietic growth factors.

The response of marrow stromal cells transformed with wild-type simian virus 40 to recombinant growth factors was examined. When transformed stromal cells were plated in semisolid medium without the addition of growth factors, only 0.4% of cells formed colonies while with the addition of recombinant factors such as interleukin 1 (IL-1) or tumor necrosis factor (TNF), up to 10% of the cells formed colonies. Colonies were individually plucked and cell lines were developed that could be analyzed for expression of growth factors. The data show that unstimulated marrow stromal cells lines produced no detectable colony-stimulating activity. However, cell lines derived from "autonomously growing colonies" and from colonies grown with T cell-conditioned medium, with IL-1 alpha or beta, or with TNF alpha produced colony-stimulating activity and transcripts for granulocyte/macrophage-colony-stimulating factor (CSF), granulocyte-CSF, and IL-1 beta. A novel feature of the cell lines derived from colonies was that the production of growth factors was constitutive and persisted in excess of 4 m.

Base Sequence↗