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Biomedical subjects

J Anderson

Publications and source records attributed to J Anderson.

At least 595 records · Page 33Linked to original sources

Pulmonary epithelial permeability in bronchiectasis.

We measured pulmonary epithelial permeability in 17 non-smoking patients with generalized bronchiectasis, of whom six had cystic fibrosis, by determining the half-time clearance from lung to blood (T1/2LB) of inhaled 99mTc-labelled diethylene triamine pentaacetate. Their age range was 15-79 years and the range of their FEV1 measurements was 20-87% of the predicted normal. Sputum obtained by prestudy chest physiotherapy revealed significant colonies of Pseudomonas aeruginosa in six, Haemophilus influenzae in three, Staphylococcus aureus in three and Pasteurella mitocida in one patient, while in the remainder there was normal flora only. Lung clearance was significantly faster in the 13 culture-positive patients (mean T1/2LB = 28 minutes) compared with the four culture-negative patients (mean T1/2LB = 54 minutes). There was no correlation between T1/2LB and prestudy FEV1. The study was repeated in six patients following a course of antibiotics. In two patients only was the sputum cleared of organisms and in those the lung permeability decreased significantly. There was no change in lung permeability in the four patients in whom it was impossible to eradicate the sputum organisms. Thus, in our patients with generalized bronchiectasis, lung permeability was increased only in those with both purulent sputum and significant colonization of the respiratory tract by bacterial pathogens. However, this increase in lung permeability was not associated with worse lung function.

Adolescent↗

Fourier analysis of ventricular fibrillation and synchronization of DC countershocks in defibrillation.

Spectral analysis of the first 40 seconds of ventricular fibrillation confirmed the presence of a large periodic component in fibrillation, with a dominant frequency of 9.9 +/- 0.7 Hz and a narrow bandwidth. To determine whether less energy was required for defibrillation at any particular phase of the ventricular fibrillation cycle, the authors studied the effect of synchronization of the countershock to the peaks and troughs of the ventricular fibrillation waveform in 12 dogs anesthetized with sodium pentobarbitone (35 mg/kg iv). There was no significant difference in threshold-delivered energy or threshold-delivered current between shocks synchronized to the peaks of ventricular fibrillation, shocks synchronized to the troughs of ventricular fibrillation, and unsynchronized shocks.

Animals↗

Pharmacodynamics and tolerance of oral sustained release ritodrine.

A new oral sustained release formulation of ritodrine was tested for patient tolerance in this open study. The doses tested were 120 mg/day, 240 mg/day, and 360 mg/day. No objective toxicity was seen at any level. Doses of 120 mg/day and 240 mg/day were well-tolerated. Of the subjects who received the 360 mg/day dose, most tolerated it well.

Administration, Oral↗

Routine preoperative ultrasonography and cesarean section.

This prospective investigation was undertaken to determine whether routine ultrasound visualization of the gravid uterus shortly before cesarean section would provide useful information in determining the site for uterine incision. Complete data were gathered on 124 pregnancies using a portable real-time ultrasound machine. Determination of the placenta and umbilical cord locations, fetal presentation, and amniotic fluid volume were reliable. Compared with a matched group without ultrasonic visualization, the eventual site for uterine incision and morbidity to the mother and fetus were not significantly different. Although routine visualization of the intrauterine contents before surgery is not necessary, worthwhile information may be gained in select cases to confirm a previously suspected noncephalically presenting fetus or a low anterior placenta.

Cesarean Section↗

Plasma corticotrophin-releasing factor (CRF) in normal pregnancy.

Corticotrophin-releasing factor (CRF) was measured directly in maternal plasma using an immunoradiometric assay (IRMA). In the first and second trimester CRF levels were within the non-pregnant range (mean 15 pg/ml). A total of 72 women was followed sequentially from 28 weeks until delivery and CRF levels rose from a median of 20 pg/ml at 28 weeks to 1320 pg/ml at 40 weeks and 1732 pg/ml during labour. There was a strong correlation (rs = 0.81, P less than 0.001) between gestational age and CRF levels. The rate of rise of CRF (pg/ml) per week was associated with weight gain (rs = 0.36, P less than 0.05) but with no other obstetric variable. There was an association between umbilical cord and maternal plasma CRF levels (rs = 0.54, P less than 0.01).

Corticotropin-Releasing Hormone↗

Plasma corticotrophin-releasing factor (CRF) in abnormal pregnancy.

Maternal plasma levels of cortiocotrophin-releasing factor (CRF) have been measured in abnormal pregnancy states to assess their potential as biochemical markers for at-risk pregnancies. CRF levels were not significantly altered in patients with hydatidiform mole, polyhydramnios or diabetes. CRF levels were elevated in pregnancies complicated by accidental antepartum haemorrhage at 28 weeks (P less than 0.03) but not for the rest of the third trimester. In twin pregnancies CRF levels were significantly raised throughout the third trimester (28-32 weeks, P less than 0.01; 34-36 weeks, P less than 0.001). In patients with pregnancy-induced hypertension (28 weeks, P less than 0.001; 32-36 weeks, P less than 0.001; and 38-40 weeks, P less than 0.01), preterm labour and premature rupture of the membranes (28 weeks, P less than 0.004; 30-32 weeks, P less than 0.002; and 34-36 weeks, P less than 0.001), CRF levels were significantly raised and in some patients levels were elevated 11 weeks before the onset of signs or symptoms. These observations raise the possibility that maternal CRF measurement may be of use as a predictive indicator of certain at-risk pregnancies.

Corticotropin-Releasing Hormone↗

Hyperoxic lung damage in mice: appearance and bioconversion of peptide leukotrienes.

High concentrations of oxygen damage the lung and increase bronchoalveolar lavage (BAL) fluid levels of leukotrienes. We sought to identify the specific leukotrienes produced and their relationship to the severity of the lung damage and the inflammatory cell populations by exposing mice to 100% oxygen for up to 4 days. Leukotrienes were not detected in BAL fluid from air-exposed mice. Leukotriene D4 (LTD4) was found after 2 days of exposure to 100% oxygen, increased with longer periods of exposure, and then decreased while LTE4 appeared when the lung damage became severe. LTB4 and LTC4 were not found at any time. Neutropenic mice had identical results, indicating that neutrophils were not the source of the leukotrienes. To determine why LTC4 was not found and why LTD4 decreased and LTE4 increased on day 4, we measured the metabolic capacity of BAL supernatant for leukotrienes. Incubation of LTD4 in BAL supernatant from air-exposed mice resulted in the conversion of LTD4 to LTE4, which was blocked by L-cysteine, a dipeptidase inhibitor. Faster conversion occurred after exposure to 100% oxygen for 3 and 4 days. The rate of bioconversion correlated with the BAL protein concentration (r = 0.756, P less than 0.001), and it was similar in neutropenic and nonneutropenic mice. Little LTC4 and no LTE4 were converted in BAL supernatant from air- or oxygen-exposed mice. The early and progressive increase in LTD4 suggests that sulfidopeptide leukotrienes may play a role in the pathogenesis of hyperoxic lung damage. The increased dipeptidase activity during hyperoxic exposure may serve a protective role by converting the more potent LTD4 to the less potent LTE4.

Animals↗

Determination of endotoxin levels and their impact on interleukin-1 generation in continuous ambulatory peritoneal dialysis and hemodialysis.

Endotoxins represent a family of ubiquitous bacterial lipopolysaccharides found in water and raw materials. These substances have the ability to generate interleukin-1 (IL-1) and induce fever, as well as other acute phase phenomena. A study was undertaken to determine levels of background endotoxin in (1) continuous ambulatory peritoneal dialysis solution, (2) spent dialysate subsequent to overnight dwell, (3) hemodialysis solution, and (4) Limulus amebocyte lysate-reactive material (LAL-RM) in hemodialyzers and patient plasma. Levels of endotoxin in all of the above cases were less than thought to be required to induce biological activity, such as pyrogenicity, through IL-1 generation. Although nanogram amounts of LAL-RM are associated with some hollow-fiber membranes as well as the plasma of patients on those membranes, this material per se does not appear to produce IL-1 in vitro.

Endotoxins↗

Pediatric occupational therapy in the home.

This article discusses the challenges and implications for pediatric practice in the home. Pediatric occupational therapists are moving the treatment setting from the clinic to the home. Working within the home environment requires occupational therapists to adapt their roles, functions, and treatment styles. Intervention frequently involves practical and relevant treatment, using activities and objects from the child's world. Thus, functional goals may be more realistically achieved in the child's living environment. Involvement with family members also offers opportunities to develop collaborative relationships with parents and, therefore, to integrate the intervention program into the child's home life.

Child↗

Blood pressure in obese adolescents: effect of weight loss.

The BP distribution of a group of 72 obese adolescents was determined both before and after weight loss. Weight loss was produced by a program of caloric restriction and behavior change alone (n = 26) or with a combination of caloric restriction, behavior change, and exercise (n = 25). It was demonstrated that obese adolescents have a BP distribution that is skewed 1 SD to the right of normal (P less than .01), and that with weight loss this distribution was no longer different from that of the general population. It was also shown that a weight loss program that incorporates exercise and caloric restriction produces the most desirable effect on BP reduction (ie, greatest decrease in resting systolic BP and greatest decrease in exercise diastolic and mean BP). Finally, it was demonstrated that obese adolescents have structural changes present in the forearm resistance vessels and that these structural changes are reversed to the greatest extent in the weight loss program that includes exercise.

Adolescent↗

Hyperoxic lung injury in mice: effect of neutrophil depletion and food deprivation.

Conflicting data exist on the role of neutrophils (PMNs) in the pathogenesis of hyperoxic lung damage. We examined the contribution of PMNs and the contribution of food deprivation, a frequent complication of the methods used to produced neutropenia, to the lung damage that results when mice are exposed to high concentrations of oxygen. Mice were exposed to either 100% oxygen or air for up to 4 days. Neutropenia was induced by a single tail vein injection of nitrogen mustard (NM) given 1 day before the oxygen exposure. Food deprivation, which induced the same weight loss as that found in NM-treated mice, was achieved by withholding food (fasted) during the oxygen exposure. We examined mortality; weight loss; bronchoalveolar lavage (BAL fluid) protein concentration, cell count, and differential count; the number of PMNs in blood; and lung histologic conditions by light and electron microscopy. NM-treated mice lost approximately 25% of their body weight when exposed to either air or oxygen. They also had more severe lung damage than the saline-treated mice during hyperoxic exposure, despite a marked reduction in the number of PMNs in blood, BAL fluid, and lung tissue. Although a correlation was found between the number of blood PMNs and the BAL protein concentration in the nonneutropenic mice (r = 0.69; P less than 0.001), no correlation was seen in the neutropenic mice (r = 0.26). Fasted, oxygen-exposed mice had the same weight loss as the NM mice, but they had more severe lung damage at an earlier time (day 3 vs. day 4) and greater mortality than the saline-treated and the NM-treated mice. These results indicate that PMNs are not required for either the development or progression of hyperoxic lung damage in mice; fasting increases susceptibility to the lung damage; and differences in nutritional status may explain, in part, the controversial role of PMNs in oxygen-induced lung damage.

Animals↗

The correlates of research success.

A survey was carried out of the undergraduate backgrounds and research achievements of 885 (94.1%) of all 940 medically qualified professors and readers in medical faculties in the United Kingdom. A total of 217 (24.5%) of the graduates in these senior academic positions had graduated from Oxford or Cambridge and 137 (15.5%) had an intercalated BSc. The corresponding figures for a control group matched for sex and date of graduation were 118 (13.3%) for Oxford and Cambridge (academic to control odds ratio 2.11:1) and 34 (3.8%) for the BSc (odds ratio 4.58:1). Those with an intercalated BSc in the clinical specialties raised substantially more research grants from the Medical Research Council than their peers from Oxford and Cambridge or those without a BSc. The Oxford and Cambridge group raised more grants in the non-clinical specialties. Bibliometric analysis was carried out on the United Kingdom graduates within the broad specialty of medicine (n = 218) matched for date of graduation. Academics with a BSc had a better publication record over 10 years (median number of original publications 72) than the Oxford and Cambridge group (median 59) and a substantially better record than those from other schools without a BSc (median 46). Citation analysis was carried out on subsets of the above sample matched for date of graduation and frequency of publication. Those with an intercalated BSc were cited more often (8.04 citations/paper) than the Oxford and Cambridge graduates (7.63) and substantially more than their peers without a BSc (4.16). These data show very clearly that research training or experience, or both, as an undergraduate has a substantial influence on career development and correlates positively with subsequent research performance many years later.

Achievement↗

The effect of intensive intermittent maintenance therapy in advanced low-grade non-Hodgkin's lymphoma.

One hundred and eleven patients with low-grade histology non-Hodgkin's lymphoma achieving a restaged complete response to one of three induction therapies on Eastern Cooperative Oncology Group (ECOG) protocol EST 2474 were randomized to receive either maintenance treatment with BCNU, cyclophosphamide, vincristine, and prednisone (BCVP) given every 6 weeks for an additional 18 months or no further therapy. Overall toxicity was moderate. The median progression-free survival (PFS) on maintenance therapy was 3.2 years versus 2.0 years for those observed without treatment (P = 0.02). Progression-free survival was significantly shorter for patients with nodular and diffuse pattern (ND), histiocytic or mixed histology compared with pure nodular lymphocytic, or poorly differentiated counterpart (P = 0.0007), thus confirming the prognostic significance of histologic subtypes. However, the overall survival of patients was not improved by maintenance treatment, suggesting that therapy upon relapse was an equally effective alternative clinical strategy.

Antineoplastic Combined Chemotherapy Protocols↗

Prognostic factor in neuroblastoma.

Known prognostic factors in neuroblastoma were analyzed in 124 children to determine which were independent and which were most useful in predicting outcome. The following factors were analyzed: age, sex, stage of disease, serum neuron-specific enolase (NSE), serum ferritin, E-rosette inhibition, urinary catecholamines, and histologic type according to the criteria of Shimada. Estimates of survival were calculated using the method of Kaplan and Meier. The overall survival for 124 patients was 60% at 2 years. There were significant differences in survival by pathology, age, NSE, ferritin, vanilmandelic acid (VMA): homovanillic acid (HVA) ratio, and stage. There was a strong association among NSE, age, stage, and ferritin. Using the recursive partitioning approach, it was possible to subdivide patients into three groups (based on diagnostic values of ferritin, age, and stage) with a good, intermediate, and poor prognosis and estimated 2-year survival of 100%, 62%, and 19%, respectively. Further analysis could not be done because of small numbers in the subgroups, but the results suggest that combinations of age, stage, serum ferritin, and histologic type may be able to define two populations: favorable with 80% + 2-year survival and unfavorable with less than 20%.

Child, Preschool↗