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Biomedical subjects

D C Anderson

Publications and source records attributed to D C Anderson.

At least 199 records · Page 11Linked to original sources
PubMed1992

Role of pulmonary phagocytes in host defense against group B streptococci in preterm versus term rabbit lung.

Intrapulmonary clearance of group B streptococci (GBS) occurred in term rabbits 4 and 8 h after infection; GBS growth was evident in preterm rabbits at 8 h. Bronchoalveolar lavage revealed 17-fold higher numbers of pulmonary alveolar macrophages (PAM) in term versus preterm animals immediately after infection, whereas polymorphonuclear leukocyte (PMNL) recruitment was 13-fold greater in preterm than term rabbits at 8 h. Anti-CD18 monoclonal antibody R15.7 did not reduce PMNL influx or GBS killing in term animals. R15.7 failed to inhibit PMNL influx but augmented GBS growth in preterm animals. R15.7 significantly impaired GBS phagocytosis by preterm and term PMNL in vitro but had no effect on ingestion of GBS by preterm and term PAM. Thus, GBS infection initiates PMNL recruitment into lungs of preterm rabbits by CD18-independent mechanisms, but phagocytosis of GBS by PMNL is largely CD18-dependent. The poorer outcome of GBS pneumonia in preterm versus term newborns may result from low levels of PAM, thereby mandating recruitment of PMNL as a second phagocytic defense.

Animals↗
PubMed1992

Expression of an oestrogen receptor-related antigen in human endometrium: a microphotometric study.

The expression of an oestrogen receptor-related antigen has been measured by microspectrophotometry in the glandular epithelium and stroma of tissue sections from endometrial biopsies of women administered exogenous replacement of sex steroids because of premature ovarian failure. We have demonstrated that previously dormant endometrium is capable of expressing an antigen related to oestrogen receptors and that its distribution is influenced by the sex steroid environment. Immunohistochemical staining was more intense (P less than 0.001) in the glandular compared to the stromal cells in tissue exposed solely to oestradiol. With the administration of progesterone, the stromal staining intensity increased (P less than 0.0001) and that of the glandular staining decreased (P less than 0.0001). No assumption, however, has been made to infer that colour is stoichiometrically related to the concentration of antigen present. Further validation of immunohistochemical procedures is required because histological localization and measurement of immunohistochemical staining may be straightforward, but its relationship to antigen concentration remains unproven.

Antibodies, Monoclonal↗
PubMed1992

Abdominal irradiation in childhood; the potential for pregnancy.

OBJECTIVE: To investigate the impact of premature ovarian failure due to whole abdominal radiotherapy (DXT) in childhood on uterine physical characteristics and blood flow and measuring the uterine response to exogenous sex steroid replacement. DESIGN: A comparative observational study SUBJECTS: 10 women with premature ovarian failure due to treatment with whole abdominal irradiation in childhood. A comparison group of 22 women with premature ovarian failure who had not received whole abdominal DXT. MAIN OUTCOME MEASURES: Uterine length and uterine blood flow measurement plus serial assessment of endometrial thickness during a cycle of exogenous sex steroid replacement. RESULTS: Uterine length was significantly less (P less than 0.01) in women who had been exposed to whole abdominal DXT in childhood (mean 4.1 cm, 2SE 0.8) compared with a mean of 7.3 cm (2SE 0.6) in the comparison group. The three women in the DXT group who were studied serially had no increase in endometrial thickness in response to physiological sex steroid replacement therapy and most of the 10 irradiated women had no detectable uterine blood flow with Doppler ultrasound. CONCLUSIONS: Uterine musculature and blood flow are irreversibly affected by high dose irradiation in childhood. Non-invasive assessment of this nature may predict potential for pregnancy following ovum donation and embryo transfer.

Adult↗
PubMed1992

Bone abnormalities and severe arthritis in pachydermoperiostosis.

Two patients with pachydermoperiostosis were studied in whom the predominant features at presentation were severe and disabling knee and ankle joint pain in association with distal long bone pain. Analysis of synovial fluid from the knee joints showed non-inflammatory changes. In one patient a bicortical iliac crest bone biopsy specimen, taken after labelling with demeclocycline, showed appositional rates which were increased in cortical bone but reduced in trabecular bone. This mismatching resulted in trabecular osteoporosis, which occurred in association with increased numbers of osteoclasts, findings which suggest differential functional changes affecting the two bony envelopes.

Adolescent↗
PubMed1992

Difficulties in localization and treatment of insulinomas in type 1 multiple endocrine adenomatosis (MEA).

A 15 year old girl with a family history of type 1 multiple endocrine adenomatosis presented with reversible neurological disturbances, hypoglycaemia and hyperinsulinaemia. Initial radiology was normal, but portal venous sampling suggested an insulinoma in the tail of the pancreas which was removed with conservation of the spleen. Hypoglycaemia persisted despite high doses of diazoxide and intravenous dextrose. A second laparotomy revealed a pancreatic endocrine tumour and sub-total pancreatectomy was performed. Histology revealed islet cell microadenomatosis. Hypoglycaemia persisted despite treatment with somatostatin analogues and 40% intravenous dextrose was required to maintain normoglycaemia. A possible lesion near the splenic hilum on computed tomographic scan was reported as a splenunculus although further peripheral, hepatic and portal venous sampling suggested hepatic or systemic lesions. A positron emission scan and selective visceral angiography suggested a lesion in the left upper quadrant. Acute lactic acidosis, rhabdomyolysis and renal failure supervened. Post mortem revealed the putative 'splenunculus' to be a residual insulinoma, whilst the splenic vein was thrombosed, accounting in part for discrepant venous sampling data. Hyperinsulinaemia in type 1 multiple endocrine adenomatosis may require more aggressive surgical and hormonal intervention than when dealing with solitary insulinomas. Insulinomas may mimic developmental abnormalities on computed tomographic scanning.

Adolescent↗
PubMed1992

Acute intermittent porphyria treated by testosterone implant.

The hereditary disorder acute intermittent porphyria is potentially fatal. Many more females present with active disease than males and some have attacks related to their menstrual cycle and pregnancy. We present a female patient who was diagnosed while pregnant at 19 years. She subsequently developed life-threatening attacks pre-menstrually at 24 years; these were associated with weight loss. Initial treatment was with high calorie feeding via a naso-gastric tube, followed by a gastrostomy. Subsequent gonadotrophin suppression with intranasal luteinizing hormone-releasing hormone analogue (buserelin) thrice daily met with limited success. We implanted 100 mg of testosterone subcutaneously in November 1989. The buserelin was discontinued in January 1990 and menses returned 3 months later. There have been no serious attacks since then. Repeat implantation was performed at 6 monthly intervals until her present pregnancy. Baseline biochemical parameters have remained high and unaltered despite treatment although the testosterone has clearly had a marked clinical benefit, without side effects.

Acute Disease↗
PubMed1992

Neuropeptides promote neutrophil adherence to endothelial cell monolayers.

The objective of this study was to determine whether substance P and calcitonin gene-related peptide (CGRP), at physiologically relevant concentrations, affect leukocyte-endothelial cell adhesion. Confluent monolayers of human umbilical vein endothelial cells (HUVEC) were incubated (40 min) with freshly isolated human neutrophils in the presence or absence of substance P or CGRP (10(-11) M). Both substance P and CGRP caused a significant increase (2-fold) in neutrophil adherence to HUVEC. Monoclonal antibodies (MAb) directed against the leukocyte adhesion glycoproteins CD11/CD18 (MAb IB4) and L-selectin (MAb DREG56) did not attenuate substance P-induced adhesion. Antibodies directed against the endothelial cell adhesion molecules E-selectin (MAb CL2) and ICAM-1 (MAb R6.5) were also without effect on substance P-induced neutrophil adhesion. Similar results were obtained when either MAb IB4, DREG56, CL2, or R6.5 was coincubated with CGRP-stimulated neutrophils and endothelial cells. Phorbol 12-myristate 13-acetate-stimulated neutrophil adherence was significantly attenuated by MAb IB4, indicating that CD11/CD18 participates in this adhesion process. The results of this study indicate that 1) the neuropeptides substance P and CGRP promote neutrophil adherence to venular endothelium and 2) the neuropeptide-induced adhesion is not mediated by the adhesion molecules CD11/CD18, L-selectin, E-selectin, or ICAM-1.

Antibodies, Monoclonal↗
PubMed1992

Anoxia/reoxygenation-induced neutrophil adherence to cultured endothelial cells.

Previous studies have shown enhanced neutrophil adhesion to endothelial cells exposed to anoxia and then reoxygenated (A/R). To define the molecular basis for these observations, we evaluated the relative roles of CD11/CD18 determinants (CD11a and CD11b) of neurtrophils and the endothelial adhesion proteins intercellular adhesion molecule 1 (ICAM-1) and endothelial-leukocyte adhesion molecule 1 (ELAM-1). Human umbilical vein endothelial cell (HUVEC) monolayers were exposed to anoxia for 30 min, reoxygenated, and then reacted with 51Cr-labeled neutrophils in adhesion assays. Neutrophil adhesion to HUVEC exposed to A/R was significantly increased (2.7-fold) as compared with that observed with normoxic (control) HUVEC. This A/R-induced hyperadherence was significantly diminished by monoclonal antibodies (MAb) directed at CD11a, CD11b, CD18 or ICAM-1, but not by MAb directed at ELAM-1. The inhibitory effects of anti-CD11a and anti-CD11b were additive and equivalent to that of anti-CD18 MAb. A/R did not elicit increased levels of ICAM-1 or ELAM-1 mRNA or surface protein. However, immunofluorescence flow cytometry indicated that incubation of neutrophils in supernatants of A/R-conditioned HUVEC elicited an increase of surface CD11b and CD18, but not CD11a. Supernatants from A/R-conditioned HUVEC promoted neutrophil adherence to naive HUVEC, and this hyperadhesivity was diminished by a platelet-activating factor (PAF) receptor antagonist and catalase but not by a 5-lipoxygenase inhibitor, a leukotriene B4 receptor antagonist, or superoxide dismutase. These studies indicate that A/R promotes neutrophil adherence via CD11a/CD18- and CD11b/CD18-dependent interactions with ICAM-1 that appear to be mediated by hydrogen peroxide and PAF.

Antibodies, Monoclonal↗
PubMed1992

Kinetics of C5a release in cardiac lymph of dogs experiencing coronary artery ischemia-reperfusion injury.

Previous studies of myocardial ischemia suggest that complement activation may play a central role in the inflammatory response during reperfusion. Our previous work has demonstrated neutrophil chemotactic activity to be present in reperfusion canine cardiac lymph after myocardial ischemia and infarction. To evaluate the contribution of the complement-dependent anaphylatoxin C5a to this neutrophil chemotactic activity, rabbit antiserum to canine C5a was prepared. At dilutions > 1:500 but < 1:2,000, the antiserum abolished the ability of zymosan-activated dog serum to induce a ruffled, bipolar morphology in isolated neutrophils used as a bioassay of chemotactic stimulation. This antiserum did not affect similar morphological changes in neutrophils exposed to platelet activating factor (10(-7)-10(-6) M) or recombinant human interleukin-8 (10(-9)-10(-8) M); thus, we deemed it functionally specific for canine C5a. In a pattern similar to what we previously reported, cardiac lymph collected before a 1-hour ligation of the left circumflex coronary artery had little ability to alter the morphology of canine neutrophils (shape change index, 11.3 +/- 4.6, mean +/- SEM; n = 7), but by 1 hour of reperfusion, lymph activated neutrophils significantly in five of seven dogs (mean shape change index, 72.6 +/- 17.7; p < 0.01). At 2 hours of reperfusion, neutrophil activation by lymph occurred in six of seven dogs (mean shape change index, 103.1 +/- 22.2). At 3 hours of reperfusion, cardiac lymph of only three of six dogs caused neutrophil activation, and at 4 hours of reperfusion, this activity was evident in lymph from only two of five dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Neutrophil adherence to isolated adult cardiac myocytes. Induction by cardiac lymph collected during ischemia and reperfusion.

Canine neutrophils can be induced to adhere in vitro to isolated adult cardiac myocytes by stimulation of the neutrophils with chemotactic factors such as zymosan-activated serum (ZAS) only if the myocytes have been previously exposed to cytokines such as interleukin 1 (IL-1) or tumor necrosis factor-alpha. These cytokines induce synthesis and surface expression of intercellular adhesion molecule-1 (ICAM-1) on the myocyte, and neutrophil adhesion is almost entirely CD18 and ICAM-1 dependent. The present study examines cardiac-specific lymph collected from awake dogs during 1-h coronary occlusion and 3 d of reperfusion for its ability to induce both ICAM-1 expression in cardiac myocytes, and neutrophil-myocyte adherence. Reperfusion lymph induced ICAM-1 expression in isolated myocytes, and myocyte adherence to ZAS-stimulated neutrophils that was completely inhibited by anti-CD18 and anti-ICAM-1 monoclonal antibodies. This activity peaked at 90 min of reperfusion and persisted for up to 72 h. Preischemic lymph was not stimulatory. IL-1 appeared not to be a stimulating factor in lymph in that dilutions of lymph were found to inhibit the stimulatory effects of recombinant IL-1 beta. However, investigation of interleukin 6 (IL-6) revealed that recombinant IL-6 stimulated myocyte adhesiveness for ZAS-stimulated neutrophils (ED50 = 0.002 U/ml) and expression of ICAM-1 by isolated myocytes. IL-6 neutralizing antibody markedly reduced the ability of reperfusion lymph to stimulate adhesion and ICAM-1 expression, and estimates of levels of IL-6 in reperfusion lymph ranged from 0.035 to 0.14 U/ml. These results indicate that cytokines capable of promoting neutrophil-myocyte adhesion occur in extracellular fluid during reperfusion of ischemic myocardium, and that one of these cytokines is IL-6. Neutrophil-myocyte adhesion may be of pathogenic significance because it may enhance the cytotoxic activity of the neutrophil.

Animals↗
PubMed1992

Expression and regulation of L-selectin on eosinophils from human adults and neonates.

L-Selectin, previously known as LEC.CAM-1, LECAM-1, LAM1, and as the MEL-14, Leu-8, TQ1, and DREG-56 antigens, is a leukocyte membrane protein that participates in adhesion to endothelium. We studied its expression on eosinophils using flow cytometry and the MAb Dreg-56 and Leu-8. Unstimulated peripheral blood eosinophils from healthy adults expressed about one third the level of L-selectin as neutrophils (mean +/- SD specific fluorescence: 20.9 +/- 3.2 versus 54.5 +/- 8.4, p = 0.0001, n = 18). After stimulation with A23187, L-selectin expression on eosinophils was rapidly lost. This was temporally correlated with increased expression of Mac-1 (CD11b/CD18); the kinetics on eosinophils and neutrophils were similar. Eosinophil expression of L-selectin decreased modestly after stimulation with platelet activating factor, but was minimally affected by N-formyl-methionyl-leucyl-phenylalanine, leukotriene B4, or C5a compared with their effects on neutrophils. Eosinophils from cord blood of healthy neonates born at term expressed less L-selectin than adult eosinophils (10.4 +/- 3.8 versus 19.4 +/- 2.7, p = 0.0001, n = 9); the relative reduction was the same as on cord blood neutrophils (36.4 +/- 8.2 versus 55.5 +/- 4.8, p = 0.0001, n = 9). Relative to baseline expression, the responses of neonatal and adult cells to stimulation did not differ. We conclude that neonatal eosinophils have abnormalities in L-selectin expression similar to neonatal neutrophils and suggest that decreased expression of L-selectin and a diminished responsiveness to direct stimulation with chemotactic factors are possible mechanisms that may limit the exudation of eosinophils.

Adult↗
PubMed1992

Role of the ovary in the synthesis of placental protein-14.

Women with absent ovarian function provide an opportunity to investigate the ovarian contribution to secretion of placental proteins (PP), such as PP14, in early pregnancy. We present data on serum PP14 levels in 12 women (median age, 30.5 yr; range, 26-37 yr) with premature ovarian failure (POF) who conceived after ovum donation and embryo transfer with exogenous sex steroid support using transdermal (n = 5) or oral (n = 7) estradiol and vaginal (n = 8) or im (n = 4) progesterone. The women were closely monitored throughout early pregnancy, with measurement of serum levels of estradiol (E2), progesterone (P4), and PP14. Levels of E2 and P4 were entirely normal. Levels of PP14 were significantly subnormal (P = 0.008) in all 12 agonadal women compared with levels of PP14 in a control group of women with normal ovarian function between 6-12 weeks gestation. Basal and peak levels for subjects with absent ovarian function were 40 and 124 micrograms/L, respectively. For each week between 6-12 weeks of pregnancy, the mean serum levels of PP14 for women with normal ovarian function were between 706-940 micrograms/L. These observations support the concept that PP14 arises from the ovary in early pregnancy or that factors under the control of the maternal ovary are involved in its production by the endometrium.

Adult↗
PubMed1992

Trends in the teaching of neurology to family practice residents, 1981-1990.

A decade ago, less than one-half of the family practice (FP) residency programs surveyed provided a defined rotation in neurology. To learn how neurology is currently being taught in FP residencies, we sent questionnaires to 384 approved FP residencies in the United States, receiving responses from 241 (63%). Seventy-eight percent provide a defined rotation in neurology, usually in the form of a preceptorship with a community neurologist, and 57% systematically present the core curriculum recommended by the American Academy of Neurology and the American Academy of Family Physicians in 1987. Asked about the level of cooperation they encounter in recruiting neurologists to teach, 54% of the respondents reported "too little" or "no" cooperation from academic neurologists, while just 20% reported these responses in regard to community neurologists. Most (87%) reported that involvement in the residency program leads to increased patient referrals for the participating neurologist. Most (81%) respondents would welcome more participation by neurologists.

Education, Medical, Graduate↗
PubMed1992

Performance of crosses among Hereford, Angus, and Simmental cattle with different levels of Simmental breeding: VI. Maternal heterosis of 3- to 8-year-old dams and the dominance model.

Data from Hereford, 25% Simmental-75% Hereford, 50% Simmental-50% Hereford, and 75% Simmental-25% Hereford dams were used to estimate maternal heterosis and level of agreement with the dominance model. Cows were located at the Northern Agricultural Research Center near Havre, MT and were managed consistent with practices for western range environments. Sample halves of dam breed groups were bred to Charolais and Tarentaise sires to produce calves at 3 to 8 yr of age. There were 766 exposures to breeding that resulted in 581 calves. Breed group means for most traits supported the dominance model. Maternal heterosis was estimated by regression techniques for 22 cow and calf traits. Maternal heterosis was not significant for day of conception, number of services, gestation length, or calving difficulty. Estimates of maternal heterosis for calf growth traits ranged from .7% for weaning height to 5.2% for weaning weight and 7.5% for weaning condition score. Calf weight per unit of cow weight at weaning showed significant maternal heterosis (7.1%). Higher levels of maternal heterosis were exhibited for milk production (8.2 to 11.1%) and the negative, but nonsignificant, estimate of maternal heterosis for early minus late milk production suggested more persistent lactation for crossbred cows. Maternal heterosis was 11.5% for proportion of dams that calved and 10.4% for proportion of dams that weaned calves. Calf weaning weight per cow exposed to breeding, a characteristic combining calf growth and dam reproduction, exhibited 17.9% maternal heterosis.

Animals↗
PubMed1992

Senior medical students as simulated patients in an objective structured clinical examination: motivation and benefits.

Third and fourth year medical students were recruited to participate as simulated patients and examiners in an Objective Structured Clinical Examination (OSCE) administered for second year medical students. Students reported they were motivated to participate, not only by the honorarium, but because they believed the OSCE would be fun and interesting and because they were interested in medical education and in improving clinical evaluation. The third and fourth year medical students benefitted academically and financially from participation. Faculty benefitted by having a readily available source of enthusiastic and knowledgeable simulated patients.

Education, Medical, Undergraduate↗
PubMed1992

Results of a prospective randomized trial for treatment of severely brain-injured patients with hyperbaric oxygen.

The authors enrolled 168 patients with closed-head trauma into a prospective trial to evaluate the effect of hyperbaric oxygen in the treatment of brain injury. Patients were included if they had a total Glasgow Coma Scale (GCS) score of 9 or less for at least 6 hours. After the GCS score was established and consent obtained, the patient was randomly assigned, stratified by GCS score and age, to either a treatment or a control group. Hyperbaric oxygen was administered to the treatment group in a monoplace chamber every 8 hours for 1 hour at 1.5 atm absolute; this treatment course continued for 2 weeks or until the patient was either brain dead or awake. An average of 21 treatments per patient was given. Outcome was assessed by blinded independent examiners. The entire group of 168 patients was followed for 12 months, with two patients lost to follow-up study. The mortality rate was 17% for the 84 hyperbaric oxygen-treated patients and 32% for the 82 control patients (chi-squared test, 1 df, p = 0.037). Among the 80 patients with an initial GCS score of 4, 5, or 6, the mortality rate was 17% for the hyperbaric oxygen-treated group and 42% for the controls (chi-squared test, 1 df, p = 0.04). Analysis of the 87 patients with peak intracranial pressures (ICP) greater than 20 mm Hg revealed a 21% mortality rate for the hyperbaric oxygen-treated patients, as opposed to 48% for the control group (chi-squared test, 1 df, p = 0.02). Myringotomy to reduce pain during hyperbaric oxygen treatment helped to reduce ICP. Analysis of the outcome of survivors reveals that hyperbaric oxygen treatment did not increase the number of patients in the favorable outcome categories (good recovery and moderate disability). The possibility that a different hyperbaric oxygen treatment paradigm or the addition of other agents, such as a 21-aminosteroid, may improve quality of survival is being explored.

Adult↗
PubMed1992

Evidence for a lentiviral etiology in an epizootic of immune deficiency and lymphoma in stump-tailed macaques (Macaca arctoides).

A retrospective study determined that an epizootic of immune suppression and lymphoma in stump-tailed macaques (Macaca arctoides) that began in 1976 was associated with a horizontally spread lentivirus infection. This conclusion was based on serology, epidemiology, pathology, and virus isolation. The lesions found in the stump-tailed macaques were more compatible with lesions seen in SIV-infected rhesus than those seen in rhesus macaques infected with type D retroviruses. A lentivirus, isolated from a rhesus inoculated with lymph node homogenate from a stump-tailed macaque, was designed SIVstm and was pathogenic for rhesus macaques. The isolate was antigenically related to other SIVs as well as to HIV-1 and HIV-2. Two surviving stump-tailed macaques sent to another colony carried SIVstm latently for at least 7 years and disseminated it throughout that colony.

Animals↗