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Biomedical subjects

D Spence

Publications and source records attributed to D Spence.

At least 55 records · Page 3Linked to original sources
PubMed1993

Myoblast transfer in Duchenne muscular dystrophy.

One biceps muscle of 8 patients with Duchenne muscular dystrophy was injected at 55 sites with a total of 55 million viable, purified, and contamination-free normal myoblasts (myoblast transfer). The other biceps of each patient was injected with a placebo to serve as a control. The procedure was blinded to the patients, parents, and investigators. Myoblasts derived from a biopsy specimen of the fathers were cultured and purified under strict conditions and carefully screened for microbial contamination. All patients received cyclophosphamide for immunosuppression for 6 or 12 months. No serious complications were observed after myoblast transfer, indicating that the procedure is safe. The overall therapeutic efficiency of myoblast transfer was poor as judged by the results in maximal voluntary force generation, dystrophin content of the muscle, magnetic resonance imaging of the muscle, and the lack of donor-derived DNA and dystrophin messenger RNA in the injected muscle. An improved efficiency of the take of myoblasts might be achieved by using younger cells and injecting the myoblasts with a myonecrotic agent (to increase the prevalence of regeneration) and a basal laminal fenestrating agent.

Analysis of Variance↗
PubMed1993

Glanzmann's thrombasthenia with mild von Willebrand's disease.

A Saudi Arabian family is reported in which Glanzmann's thrombasthenia and von Willebrand's disease occurred simultaneously. The daughter presented with menorrhagia and gave a history of gastrointestinal bleeding and a strong family history of bleeding disorder. Full haematological investigations were performed on the propositus, parents, and siblings, including complete blood count, bleeding time, prothrombin time, partial thromboplastin time, factor VIII:C, von Willebrand factor, ristocetin cofactor, platelet aggregometry, platelet glycoprotein Ib and IIb/IIIa and platelet antigen PLT-1 (Coulter Clone). The propositus had Glanzmann's thrombasthenia, both parents had mild von Willebrand's disease and were carriers of Glanzmann's thrombasthenia. Three symptomatic brothers had both Glanzmann's thrombasthenia and von Willebrand's disease; two asymptomatic brothers had von Willebrand's disease only and one had completely normal results. Those family members with both diseases were more severely affected than those with just one disease. In areas where consanguineous marriage is common, such as Saudi Arabia, multiple haemostatic abnormalities may occur, and investigation should not stop with the discovery of a single abnormality. The increased clinical severity of bleeding, including haemarthroses, in those patients having both congenital defects emphasises the importance of von Willebrand factor in glycoprotein Ib-mediated platelet adhesion.

Adolescent↗
PubMed1992

Risk factors for coronary artery disease in patients with systemic lupus erythematosus.

PURPOSE: To estimate the frequency of and examine risk factors for coronary artery disease (CAD) in patients with systemic lupus erythematosus (SLE) in a prospective longitudinal study. PATIENTS AND METHODS: Patients were SLE are enrolled in The Johns Hopkins Lupus Cohort, a prospective study of outcomes in 229 subjects with SLE. CAD was defined as angina, myocardial infarction, or sudden death. Data on CAD risk factors were obtained prospectively every 3 months and were analyzed using univariate and multiple logistic regression. RESULTS: CAD occurred in 19 (8.3%) of 229 patients with SLE and accounted for 3 (30%) of 10 deaths as of December 31, 1990. Compared to subjects without CAD, those with CAD were more likely to have been older at both diagnosis of SLE (37.1 years versus 28.9 years, p = 0.004) and at entry into the cohort (47.1 years versus 34.7 years, p < 0.0001), to have a longer mean duration of SLE (12.3 years versus 8.1 years, p = 0.013) and a longer mean duration of prednisone use (14.3 years versus 7.2 years, p < 0.0001), to have a higher mean serum cholesterol (271.2 mg/dL versus 214.9 mg/dL, p < 0.0001) or a cholesterol level greater than 200 mg/dL (odds ratio [OR] 14.5, 95% confidence intervals [CI] 1.9, 112.1), and to have both a history of hypertension (OR 3.5, 95% CI 1.3, 9.6) and a history of use of antihypertensive medications (OR 5.5, 95% CI 1.8, 17.2). There were no significant associations with other known CAD risk factors such as smoking, diabetes, family history of CAD, race, or sex, or variables related to steroid therapy including the presence of cushingoid features or ever use of corticosteroids. The best multiple logistic regression model for CAD included age at diagnosis, duration of prednisone use, requirement for antihypertensive treatment, maximum cholesterol level, and obesity (using NHANES-II [National Health and Nutrition Examination Survey] definitions). CONCLUSION: Primary and secondary prevention strategies directed at hypertension, hypercholesterolemia, and obesity, as well as other known CAD risk factors, should be routinely employed in the management of patients with SLE.

Adult↗
PubMed1992

Coronary artery disease risk factors in the Johns Hopkins Lupus Cohort: prevalence, recognition by patients, and preventive practices.

Known risk factors for coronary artery disease are very common in the Hopkins Lupus Cohort, in spite of the fact that the average patients age is only 38.3 years. Three or more known risk factors were found in 53% of patients. Risk factors for CAD were common even in patients not on a regimen of prednisone therapy during their cohort follow-up. Hypercholesterolemia increased significantly with greater average prednisone dose. Despite the frequency of risk factors, patients' awareness of the risk of CAD was low, with only 16.9% of patients believing they were at high risk for developing CAD within 5 years. In general, awareness of individual risk factors was lower in black than in white patients with SLE. Preventive practices were most commonly addressed towards hypertension. Preventive practices directed against obesity, hypercholesterolemia, and smoking were underutilized. Whether these known risk factors are sufficient in and of themselves to explain the high frequency of CAD in the cohort (8%) or whether they are "enabling" factors acting upon endothelium damaged by immune-complex disease cannot be addressed by this study. However, both further investigation of these risk factors and attention to lifestyle and pharmacologic approaches to risk factor reduction are indicated by this study.

Adolescent↗
PubMed1990

Homologous transformation of Cephalosporium acremonium with the nitrate reductase-encoding gene (niaD).

We report the development of a homologous transformation system for Cephalosporium acremonium using the niaD gene of the nitrate assimilation (NA) pathway. Mutants in the NA pathway were selected on the basis of chlorate resistance by conventional means. Screening procedures were developed to differentiate between nitrate reductase apoprotein structural gene mutants (niaD) and molybdenum cofactor gene mutants (cnx) as wt C. acremonium, unlike most filamentous fungi, fails to grow on minimal medium with hypoxanthine as a sole source of nitrogen. Phage clones carrying the niaD gene were isolated from a C. acremonium library constructed in lambda EMBL3 using the A. nidulans niaD gene as a heterologous probe. An 8.6-kb EcoRI fragment was subcloned into pUC18, and designated pSTA700. pSTA700 was able to transform stable niaD mutants to NA at a frequency of up to 40 transformants per microgram DNA. Transformants were easily visible since the background growth was low and no abortives were observed. Gene replacements, single copy homologous integration and complex multiple integrations were observed. The niaD system was used to introduce unselected markers for hygromycin B resistance and benomyl resistance into C. acremonium by cotransformation.

Acremonium↗
PubMed1989

The electronic spectrum of adenine by electron impact methods.

The electron energy loss spectrum of adenine has been recorded over an excitation energy range of approximately 3-22 eV for scattering angles of 3 degrees and 6 degrees. In addition to reporting accurate vapor phase peak positions, the present work supports the long-held contention that the group of peaks in the 6- to 10-eV range belong to transitions that originate from valence pi orbitals. In the vapor phase spectrum, a Rydberg transition corresponding to an n----3s excitation is readily observed with a term value of 3.45 eV relative to the first long-pair ionization potential.

Adenine↗
PubMed1986

Lineage ambiguity in acute leukemia.

Two cases of acute nonlymphocytic leukemia that showed surface phenotypes characteristic of lymphoid cells are reported. The cases, both involving female patients were studied by a variety of methods including flow cytometry and karyotyping. In Case 1, the patient, a 10-year-old girl, had poorly differentiated myeloblasts (FAB M1), which were weakly positive for Sudan black B (SBB), but negative for alpha naphthyl acetate esterase (NAE) and naphthol ASD chloroacetate esterase (CAE). Myeloperoxidase was demonstrated ultrastructurally in some of the blasts. In Case 2, the 30-year-old patient had typical myelomonocytic leukemia (FAB M4), with SBB-, NAE-, and CAE-positive blasts. Both cases were negative for terminal deoxynucleotidyl transferase. Case 1 was negative for myeloid membrane markers, whereas Case 2 was strongly positive for My7 and My9. Surprisingly, both cases showed significant positivity for B-cell restricted antigens B1, B2, and B4. These findings suggest ambiguous or dual lineage, supporting the concepts that some leukemias could arise from a pluripotent hematopoietic progenitor cell (Case 1) or from cells that though differentiated in some respects, could still preserve some early antigens (Case 2).

Acute Disease↗
PubMed1986

Slit-lamp measurement of the anterior chamber depth.

A technique is proposed which allows assessment of the anterior chamber depth with a standard table slit-lamp without any extra attachments. A final approximation is made which suggests that a 1 degree change in the angle between the observation and illumination systems of the slit lamp when the end point is reached indicates a change in anterior chamber depth of 0.1 mm.

Adult↗
PubMed1984

Unusual wound healing following removal of donor tissue for soft tissue graft.

Soft tissue grafts are regularly used in most periodontal practices to augment attached gingiva. Postoperative complications are few and of minor consequence. This case describes a possible arterio-venous shunt following removal of palatal mucosa as the donor tissue in a soft tissue autograft. The complication was managed by a surgical excision of the cavernous lesion. Healing thereafter was uneventful.

Adult↗
PubMed1980

The place of bone-marrow transplantation in acute myelogenous leukaemia.

28 patients with acute myeloid leukaemia (AML) in first remission were maintained on chemotherapy, consisting of courses of cytosine arabinoside and daunorubicin, and immunotherapy with irradiated AML cells and BCG. The relapse rate and survival rate of these patients were compared with those of a simultaneously treated group of 22 patients in first remission who received sibling bone-marrow transplants after cyclophosphamide (60 mg/kg) given for 2 days and followed by a single dose of 1000 rads total body irradiation. Substantially fewer transplanted patients (4 out of 22) than chemo-immunotherapy patients (19 out of 28) relapsed (p less than 0.005) and 14 (64%) transplanted patients remain alive, well, and disease-free. Survival curves of the two groups of patients show that the transplanted patients never fared worse than the chemo-immunotherapy patients. We suggest that when possible young AML patients in remission should be offered transplantation as an alternative form of treatment.

Adolescent↗