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Biomedical subjects

J Anderson

Publications and source records attributed to J Anderson.

At least 505 records · Page 28Linked to original sources
PubMed1991

Comparison of dextran and hematocrit effects in the pulmonary microcirculation.

We have compared the effects of an increase in perfusate viscosity induced by dextran and by hematocrit (Hct) on segmental vascular resistance in the pulmonary circulation and the effect of flow on microvascular resistance in lungs perfused with dextran and red blood cells. We isolated and perfused lungs of 39 neonatal rabbits weighing 670 +/- 250 g. To determine the effect of dextran, group 1 (n = 8) lungs were perfused with both 5% and 20% dextran 70 solutions (Hct, approximately 25%); to determine the effect of Hct, group 2 (n = 5) lungs were perfused alternately with 5% and 40% Hct solutions (5% dextran 70). In group 1 and group 2 lungs, experiments were done at constant flow and pressure. Group 3 and group 4 (each n = 4) lungs were perfused with 5% and 20% dextran 70, respectively (0 Hct); group 5 (n = 5), with 10% dextran 70; group 6 (n = 7), with 5% dextran 500; and group 7 (n = 6), with 20% dextran 70 (Hct, approximately 5%). All lungs were perfused in zone 3; airway and left atrial pressures were 6 and 8 cm H2O, respectively. To partition the circulation, we measured pressures in the pulmonary artery and left atrium continuously and pressures in 20-50-microns arterioles and 20-50-microns venules by micropuncture. We found that an increase in both the concentration and molecular weight of dextran increased perfusate viscosity and the resistance in all three longitudinal vascular segments: arteries, microvessels, and veins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Mothers' perceptions of home treatment programs for their preschool children with cerebral palsy.

Data from 8 mothers of preschool children with cerebral palsy were collected through intensive interviews concerning their experience with home programs. The data were analyzed with qualitative techniques. Each mother had previously participated in or attempted to use a home treatment program with her child, but none was currently doing so. The mothers' descriptions suggest that they selected activities that were doable and that they could integrate into their daily routines and interactions. Some important characteristics of these activities were that they were enjoyable for the child and not stressful for the child, the mother, or the family.

Attitude↗
PubMed1991

Factors determining success and energy requirements for cardioversion of atrial fibrillation: revised version.

Factors thought to affect the success of and energy requirements for cardioversion of atrial fibrillation were studied in 80 (49 male, 31 female) patients aged 21-88 (mean 61.5 years). Transthoracic impedance was measured in advance of the countershock using a 30 kHz low amplitude AC current passed through self-adhesive ECG/defibrillator pads (diameters 8 and 12 cm) applied to the chest in the antero-posterior (AP) position in 57 patients and the anteroapical (AA) position in 23 patients. Mean transthoracic impedance for all patients was 69.3 +/- 16 (SD) ohms (range 39-131 ohms), but transthoracic impedance was significantly greater in the AA than the AP position (75.4 +/- 13 vs. 66.7 +/- 16 ohms, p = 0.02). Initial energy was 50 J (delivered) and was gradually increased to a maximum of 360 J if required. Cardioversion was successful in 73 of 80 (91.2 per cent), and low energy shocks (< or = 200 J) were successful in 45 of 80 (56.2 per cent) patients. Using single factor analysis, sex, left atrial enlargement, electrode pad positions, aetiology of atrial fibrillation, presence of left ventricular failure, and prior treatment with verapamil or beta-adrenergic blockers were not significant determinants of cardioversion success or success of low energy shocks but prior treatment with digoxin was, both for cardioversion success and success at low energies. In patients with transthoracic impedance < or = 70 ohms, low energy shocks were more often successful (33 of 50, 66 per cent) than in patients with transthoracic impedance > 70 ohms (12 of 30, 40 per cent), p = 0.04. Using univariate analysis, cardioversion success with low energy shocks was not only significantly associated with prior treatment with digoxin but also with the duration of atrial fibrillation (24 hours to less than one month and one month to three years) and for shocks of < or = 100 J, with prior treatment with amiodarone. Multifactorial linear regression analysis selected, in rank order, only duration of atrial fibrillation of 24 hours to less than one month and one month to three years as significant predictors of both cardioversion success irrespective of shock strength, and success of low energy shocks.

Adult↗
PubMed1991

The use of recombinant human granulocyte-macrophage colony stimulating factor for the treatment of delayed engraftment following high dose therapy and autologous hematopoietic stem cell transplantation for lymphoid malignancies.

To test the value of recombinant human granulocyte-macrophage colony stimulating factor for the treatment of delayed engraftment following high dose therapy and autologous hematopoietic stem cell transplantation, we enrolled 12 patients with recurrent non-Hodgkin's lymphoma or Hodgkin's disease having an absolute granulocyte count less than 150 x 10(6)/l on day 30 after autologous hematopoietic stem cell infusion in an open-label, nonrandomized study. These patients were compared to 21 similar historical control patients who were not treated with colony stimulating factor. Overall, the patients treated with granulocyte-macrophage colony stimulating factor had a mean absolute granulocyte count of 704 x 10(6)/l on day 44 after stem cell infusion compared to a mean absolute granulocyte count of 408 x 10(6)/l in historical controls (p = 0.008). The number of documented bacterial and fungal infections occurring after day 30 (9 vs 0, p = 0.01) was significantly reduced in the study group. The toxicity attributed to the granulocyte-macrophage colony stimulating factor was minimal with only one patient experiencing chills. Recombinant human granulocyte-macrophage colony stimulating factor appears to be effective for the treatment of delayed engraftment following high-dose therapy and autologous hematopoietic transplantation for lymphoid malignancies, with most patients having accelerated granulocytic recovery and a reduced incidence of infections.

Adolescent↗
PubMed1991

Abnormal skeletal and cardiac muscle mitochondria induced by zidovudine (AZT) in human muscle in vitro and in an animal model.

To examine the mechanism of mitochondrial myocytotoxicity caused by long-term administration of zidovudine (AZT) in human immunodeficiency virus-positive patients, we examined the effect of AZT in vitro on human muscle in tissue culture and in vivo in rats treated with daily intraperitoneal injections of AZT at doses equivalent to the total daily dose used in acquired immunodeficiency syndrome patients. After 19 days, the AZT-treated myotubes in tissue culture exhibited abnormal mitochondria characterized by proliferation (mean +/- SD, 27.5 +/- 8 mitochondria/16 microns2 surface area, compared with 12.8 +/- 4 in the control cultures (p less than 0.001], enlarged size, abnormal cristae and electron-dense deposits in their matrix. The changes were partially reversible after AZT withdrawal. Rats treated with AZT developed weight loss, 100-fold elevation of creatine kinase, and increased serum lactate and glucose. In tissues, AZT had its highest concentration in the skeletal muscle and the heart. Skeletal and heart muscles from the treated animals, but not the controls, showed enlarged mitochondria with disorganized or absent cristae and electron-dense deposits in their matrix. Study of the mitochondrial functions assessed by evaluating stimulated oxygen consumption rate, enzymatic activities of electron transport chain and coupling state of oxidative phosphorylation (respiratory control ratio) revealed a decrease in rotenone-sensitive NADH cytochrome C reductase (complex I + III) and an uncoupling effect demonstrated by decreased respiratory control ratio. We conclude that AZT, a DNA chain terminator, is a muscle mitochondrial toxin that affects the oxidation-phosphorylation coupling and the activity of complex I and III of the mitochondrial respiratory chain.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Occupational physical demands, knee bending, and knee osteoarthritis: results from the Framingham Study.

We sought to assess occupational joint use and osteoarthritis (OA) longitudinally in a large population with multiple occupations. Subjects were members of the Framingham Heart Study cohort followed over 40 years with occupational status assessed at the beginning of the Heart Study [from Examination 1 (1948-51) through Examination 6 (1958-61)] and knee OA assessed by weight bearing knee radiograph at Examination 18 (1983-85) when mean age of subjects was 73 years. Each subject's job was characterized by its level of physical demand and whether the job was associated with knee bending. Odds ratios (OR) testing the association of job demand with OA were adjusted by logistic regression for age, body mass, knee injury history, smoking, and educational level. Men whose jobs required knee bending and at least medium physical demands had higher rates of later radiographic knee OA (at least definite osteophytes) than men whose jobs required neither (43.4 vs 26.8%; OR of OA = 2.22, 95% CI 1.38, 3.58). Rates of severe radiographic OA (osteophytes and joint space narrowing) and of bilateral radiographic OA were also significantly increased in these men. Few women had jobs requiring knee bending or that were physically demanding and these jobs were generally unassociated with later radiographic OA. Only a small number of men (n = 28) had symptomatic knee OA, and we could not confirm that it was associated with occupation in men. Thus, among men, occupations which combine knee bending and physical demands may be an important cause of radiographic OA.

Aged↗
PubMed1991

Improving a community preceptorship through a clinical faculty development program.

A department of family and community medicine has successfully used annual conferences to develop the teaching skills of clinical faculty. The conferences focus on specific topics each year, faculty are required to attend, and experienced preceptors are used as facilitators. These conferences have effectively improved the preceptors' abilities as teachers of medical students. This is dramatically illustrated by the increase in measurable objectives on the negotiated learning contracts.

Community Medicine↗
PubMed1991

Effect of oxyquinoline ointment on diaper dermatitis.

The effectiveness of oxyquinoline ointment for diaper dermatitis was tested in a randomized double-blind trial. Compared to a combined control treatment group using Desitin or A & D ointment, use of oxyquinoline ointment significantly improved rash.

Dermatologic Agents↗
PubMed1991

Vaccination of calves with a modified bacterin or oil-in-water emulsion containing alkali-detoxified Salmonella typhimurium lipopolysaccharide.

Twenty-six clinically normal colostrum-fed dairy calves were allotted to 5 groups. Calves of groups 1 and 2 served as nonvaccinated controls and were challenge-exposed with variable numbers of organisms. Group-3 calves were vaccinated SC with a modified Salmonella typhimurium bacterin. The bacterin was composed of killed acid-hydrolyzed S typhimurium G30/C21 (Re-mutant) whole cells coated with alkali-hydrolyzed S typhimurium LT-2 lipopolysaccharide, as antigen, and monophosphoryl lipid A, as adjuvant. Calves of groups 4 and 5 were vaccinated with a 2% mineral oil-in-water emulsion containing lipopolysaccharide as antigen and monophosphoryl lipid A and trehalose 6-6'-dimycolate as adjuvants. Calves of groups 3-5 were vaccinated at 2 weeks of age and again at 4 or 6 weeks of age. Adverse reactions were not observed after vaccination. Calves were challenge-exposed orally at 6 or 8 weeks of age with 1.5 X 10(11) (groups 1 and 4), or 3.0 X 10(11) (groups 2, 3, and 5) colony-forming units of S typhimurium UCD 108-11. Mortality after challenge exposure was 2 of 5 group-1 calves; 4 of 5 group-2 calves; 5 of 6 group-3 calves; 1 of 5 group-4 calves; and 4 of 5 group-5 calves. Statistical difference between calves of similarly challenge-exposed groups was not evident, indicating failure of either vaccine to protect calves of this age from oral challenge exposure with virulent S typhimurium.

Animals↗
PubMed1990

Role of recurrent hydrophobic residues in catalysis of helix formation by T cell-presented peptides in the presence of lipid vesicles.

We tested the hypothesis that the recurrence of hydrophobic amino acids in a polypeptide at positions falling in an axial, hydrophobic strip if the sequence were coiled as an alpha helix, can lead to helical nucleation on a hydrophobic surface. The hydrophobic surface could anchor such residues, whereas the peptide sequence grows in a helical configuration that is stabilized by hydrogen bonds among carbonyl and amido NH groups along the peptidyl backbone of the helix, and by other intercycle interactions among amino acid side chains. Such bound, helical structures might protect peptides from proteases and/or facilitate transport to a MHC-containing compartment and thus be reflected in the selection of T cell-presented segments. Helical structure in a series of HPLC-purified peptides was estimated from circular dichroism measurements in: 1) 0.01 M phosphate buffer, pH 7.0, 2) that buffer with 45% trifluoroethanol (TFE), and 3) that buffer with di-O-hexadecyl phosphatidylcholine vesicles. By decreasing the dielectric constant of the buffer, TFE enhances intrapeptide interactions generally, whereas the lipid vesicles only provide a surface for hydrophobic interactions. The peptides varied in their strip-of-helix hydrophobicity indices (SOHHI; the mean Kyte-Doolittle hydrophobicities of residues in an axial strip of an alpha helix) and in proline content. Structural order for peptides with helical circular dichroism spectra was estimated as percentage helicity from circular dichroism theta 222 nm values and peptide concentration. A prototypic alpha helical peptide with three cycles plus two amino acids and an axial hydrophobic strip of four leucyl residues (SOHHI = 3.8) was disordered in phosphate buffer, 58% helical in that buffer with 48% TFE, and 36% helical in that buffer with vesicles. Percentage helicity in the presence of vesicles of the subset of peptides without proline followed their SOHHI values. Peptides with multiple prolyl residues had circular dichroism spectra with strong signals, but since they did not have altered spectra in the presence of vesicles relative to phosphate buffer alone, the hydrophobic surface of the vesicle did not appear to stabilize those structures.

Amino Acid Sequence↗
PubMed1990

Chromosomal abnormalities in untreated patients with non-Hodgkin's lymphoma: associations with histology, clinical characteristics, and treatment outcome. The Nebraska Lymphoma Study Group.

We describe the chromosomal abnormalities found in 104 previously untreated patients with non-Hodgkin's lymphoma (NHL) and the correlations of these abnormalities with disease characteristics. The cytogenetic method used was a 24- to 48-hour culture, followed by G-banding. Several significant associations were discovered. A trisomy 3 was correlated with high-grade NHL. In the patients with an immunoblastic NHL, an abnormal chromosome no. 3 or 6 was found significantly more frequently. As previously described, a t(14;18) was significantly correlated with a follicular growth pattern. Abnormalities on chromosome no. 17 were correlated with a diffuse histology and a shorter survival. A shorter survival was also correlated with a +5, +6, +18, all abnormalities on chromosome no. 5, or involvement of breakpoint 14q11-12. In a multivariate analysis, these chromosomal abnormalities appeared to be independent prognostic factors and correlated with survival more strongly than any traditional prognostic variable. Patients with a t(11;14)(q13;q32) had an elevated lactate dehydrogenase (LDH). Skin infiltration was correlated with abnormalities on 2p. Abnormalities involving breakpoints 6q11-16 were correlated with B symptoms. Patients with abnormalities involving breakpoints 3q21-25 and 13q21-24 had more frequent bulky disease. The correlations of certain clinical findings with specific chromosomal abnormalities might help unveil the pathogenetic mechanisms of NHL and tailor treatment regimens.

Aged↗
PubMed1990

AIDS in Thailand.

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Acquired Immunodeficiency Syndrome↗