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Biomedical subjects

D Campbell

Publications and source records attributed to D Campbell.

At least 235 records · Page 13Linked to original sources
PubMed1989

Tissue and cell studies of the growth plate in the chondrodysplasias.

As the morphologic expression of the chondrocytic differentiation pathway responsible for bone development and growth, the growth plate has been investigated extensively in the chondrodysplasias. Unique morphologic abnormalities identified in many disorders have provided insight into pathogenetic mechanisms and have been useful diagnostically and nosologically. Biochemical studies have detected evidence of type II collagen defects in patients having disorders in the achondrogenesis type II-spondyloepiphyseal dysplasias (SED) congenita family of chondrodysplasias. Most promising may be the cell culture systems now being developed for human chondrocytes. Preliminary results suggest that they will allow the cellular and molecular biology of the dysplastic growth plate to be directly analyzed.

Cartilage↗
PubMed1989

Type II collagen screening in the human chondrodysplasias.

Abnormalities of type II collagen have been considered strong candidates for causing human condrodysplasias. We have employed peptide mapping to screen for several types of type II colagen abnormalities in cartilage samples from 66 patients with 20 separate disorders. Except for achondrogenesis type II (Langer-Saldino) and spondyloepiphyseal dysplasia (SED) congenita in which abnormalities have been described and diastrophic dysplasia in which the changes were probably secondary, no abnormalities were detected. Within the limitations of the screening technique, the results combined with other data from the literature suggest that abnormalities of this molecule are not common causes of chondrodysplasias outside of the achondrogenesis type II-SED congenita family of disorders.

Adolescent↗
PubMed1989

Neck muscle activation patterns in humans during isometric head stabilization.

A musculoskeletal system with more muscles than there are motions could be programmed in alternative ways to produce a single movement. In this case, the muscles would have the potential to be maximally responsive in multiple directions rather than responding preferentially in a single direction. To determine the response patterns of muscles in the head-neck motor system, the simultaneous activation of four of the 23 neck muscles acting on the head was recorded with both surface and intramuscular electrodes. Fifteen human subjects were tested during an isometric head stabilization task. When the EMG response patterns were plotted, each muscle demonstrated a preferred direction of activation. This preferred activation direction was consistent in all of the subjects for three of the muscles tested. The fourth muscle, splenius, was preferentially activated during neck flexion in half of the subjects and during neck extension in the other half. Increasing the force parameters of the task suggested a linear relationship between force and the EMG output in the preferred response directions. Responses in the nonpreferred directions were produced by a nonlinear change in EMG activation of the muscle. This finding could have implications for theories of how reciprocal activation and cocontraction patterns of response are elicited. Results from this study, that the CNS programs neck muscles to respond in specific orientations rather than generating an infinite variety of muscle patterns, are in agreement with our findings in the cat.

Adult↗
PubMed1989

Peritoneal dialysis following open heart surgery in children.

Over the course of the last 5 years, we have instituted peritoneal dialysis on 26 (7.7%) of 338 complex postoperative cardiac bypass cases. The mean age of dialysis patients was 0.64 +/- 0.75 years with a range of 0.1-2.5 years. The indications for the start of dialysis were oliguria (15 cases), fluid overload (three cases), hyperkalemia (one case), and anuria (seven cases). There were no complications as the result of dialysis, although two of the dialysis catheters had to be replaced. Dialysis successfully treated the starting indication in all cases. Dialysis was instituted at 47 +/- 50 (12-240) h after bypass, and lasted 111 +/- 134 (18-552) h; early institution of dialysis had no effect on mortality. Low cardiac output was a significant predictor of death in dialysis patients (p = 0.015). Age was a significant determinant of death (p = 0.0001) and the need for dialysis (p = 0.0043) in the total bypass population; the younger the patient, the greater was the likelihood of death or the need for dialysis. Age, however, was not a predictor of mortality in the peritoneal dialysis group.

Aging↗
PubMed1989

Small aortic valve annulus in children with fixed subaortic stenosis.

Twenty-one hearts with fixed subaortic stenosis (FSAS) were examined pathologically. Thirty children with no hemodynamically significant heart disease, 31 children with valvar aortic stenosis, and 25 children with FSAS were studied by echo- and angiocardiography. The following conclusions were drawn: (1) Patients with FSAS often have abnormal aortic valve leaflets as well as small aortic valve annulus. (2) A small aortic annulus/descending aorta ratio is probably present at birth, and may decrease with increasing age. (3) In some patients with FSAS the aortic valve annulus is too small for simple resection of the fibroelastic tissue. A Konno operation is needed for these patients. (4) M-mode echocardiography has not been useful in identifying abnormally small aortic valve annulus in FSAS patients.

Adolescent↗
PubMed1989

Hypersensitivity to magnesium sulfate.

Two patients who were labor and delivery nurses were treated with intravenous magnesium sulfate because of preterm labor. Both patients had a rapid and sudden onset of an urticarial eruption. The eruption cleared when magnesium sulfate was discontinued. The reactions did not affect the mothers or fetuses, but other therapies to stop labor were necessary.

Adult↗
PubMed1989

Internal frameshifts within the mitochondrial genes for cytochrome oxidase subunit II and maxicircle unidentified reading frame 3 of Leishmania tarentolae are corrected by RNA editing: evidence for translation of the edited cytochrome oxidase subunit II mRNA.

The Leishmania tarentolae cytochrome oxidase (EC 1.9.3.1) subunit II (COII) and maxicircle unidentified reading frame 3 (MURF3) mRNAs are edited internally by the addition of four and five uridine residues, respectively, which eliminate -1 and +1 reading frameshifts in the gene sequences. The editing events in COII are conserved in three kinetoplastid species, and those in MURF3 are conserved in two species. A primer extension assay showed that the ratio of edited to unedited RNA differed for each gene: 89% of the COII and 36% of the MURF3 transcripts are edited. Preliminary evidence was obtained for translation of the edited COII transcript into protein: antibodies generated against a synthetic peptide with the predicted carboxyl-terminal amino acid sequence reacted with a polypeptide of the correct molecular weight in immunoblots of a mitochondrial lysate.

Amino Acid Sequence↗
PubMed1989

Selenium and vitamin E status of healthy and institutionalized elderly subjects: analysis of plasma, erythrocytes and platelets.

Levels of selenium in whole blood, plasma, erythrocytes and platelets, glutathione peroxidase (EC 1.11.1.9; GSH-Px) activity in erythrocytes and platelets and vitamin E, low-density-lipoprotein (LDL)-cholesterol and vitamin E: LDL cholesterol in plasma were measured in seventy-five healthy subjects aged less than 65 years and twenty-eight healthy and twenty-three institutionalized elderly people aged greater than 65 years. Healthy elderly subjects had significantly lower levels of Se in whole blood and plasma when compared with younger subjects. Other measurements of Se status were not significantly different. In the healthy subjects plasma levels of vitamin E and LDL-cholesterol increased with age to 60 years and decreased above 80 years. Vitamin E: LDL cholesterol values were not affected by age. Measurements of Se and vitamin E status in the institutionalized elderly compared with the healthy elderly were all reduced with the exception of platelet Se levels and erythrocyte GSH-Px activity. Ageing per se had minimal effect on Se and vitamin E status but intercurrent illness and decreased food intake can lead to reduced levels in the elderly.

Adult↗
PubMed1989

Clinical significance of sleep-disordered breathing in Alzheimer's disease. Preliminary data.

In a study of 15 probable Alzheimer's patients and 12 healthy elderly control subjects, Alzheimer's patients had a significantly higher apnea index (patients versus controls, mean +/- SD: 6.3 +/- 6.6 vs 1.8 +/- 2.7, P less than .05) and greater maximal duration of apnea (patients versus controls, median: 50.0 vs 28.5 seconds, P less than .001), but no significant increase in oxyhemoglobin desaturation compared with controls. (The accepted normal threshold for abnormality is an apnea index more than 5.) Although three of seven psychometric tests (odd-even, category retrieval, face-hand test) showed diurnal effects on one or more of their subscores, with Alzheimer's patients having significantly poorer scores at the AM than at PM testing, overnight change scores in the psychometric tests were not significantly correlated with severity of sleep-disordered breathing. Further, only 18.1% of the disruptive (ie, requiring intervention) nocturnal behaviors of the Alzheimer's patients were temporally linked to sleep-disordered breathing. The current data suggest that sleep-disordered breathing in nonmedicated Alzheimer's patients is relatively mild and is not a predictor of either overnight mental status changes, of disruptive nocturnal behaviors, or of daytime behavioral fluctuations. Additional studies of more severely demented patients and possibly of sleeping pill effects would be useful in further evaluating the role of sleep apnea in Alzheimer behavioral changes.

Aged↗
PubMed1989

Early hyperkalaemia in very low birthweight infants in the absence of oliguria.

We reviewed 1552 admissions to a neonatal intensive care programme; seven, all with a birth weight less than 1500 g, developed early onset, non-oliguric hyperkalaemia (potassium concentration greater than 7.0 mmol/l). Although their perinatal variables were similar to those of a normokalaemic group, hyperkalaemic infants had a higher incidence of intraventricular haemorrhage and developed increased concentrations of plasma creatinine by 7 days of age.

Cerebral Hemorrhage↗
PubMed1989

The effects of prostaglandin E1 on lung injury complicating hyperdynamic sepsis in sheep.

We examined the hypothesis that PGE1 would reduce the severity of lung injury in sheep rendered septic by cecal ligation and perforation (CLP). Twenty-four to 30 h after CLP, septic lung injury was documented in 37 sheep because pulmonary lymph flow (Qlym) was increased above the baseline, nonseptic study (delta = +7.38 +/- 5.1 ml/h; p less than 0.05), whereas the lymph-to-plasma total protein ratios remained unchanged. During a subsequent 24-h "septic treatment" study period, Qlym continued to increase in an untreated study group (septic treatment minus septic delta = +10.24 +/- 4.9 ml/h; p less than 0.05), but not in sheep treated with PGE1 by continuous infusion at two doses, 1 micrograms/kg/h ("low-dose": delta Qlym = -0.04 +/- 6.1 ml/h; p = NS) and 1 microgram/kg/min ("high-dose": delta Qlym = -0.04 +/- 6.1 ml/h; p = NS. Mean pulmonary artery pressures (Ppa) increased in the untreated group during the septic treatment period (delta = +3.74 +/- 4.8 mm Hg; p less than 0.01), but not during PGE1 infusion in either of the low-dose (delta Ppa = -4.1 +/- 5.7 mm Hg; p less than 0.04) or the high-dose (delta Ppa = -0.1 +/- 6.2 mm Hg; P = NS) groups. Unlike other study groups, the PaO2 fell in the high-dose PGE1 group during the septic treatment study (delta PaO2 = -15.0 +/- 9.6 mm Hg; p less than 0.01). During a study period of drug withdrawal 24 h after the septic-treatment period, Qlym again increased in the low-dose PGE1 group such that the untreated and PGE1 groups were no longer dissimilar.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1989

Granulocyte independence of pulmonary oxygen toxicity in the rat.

The role of neutrophils in the mediation of severe normobaric hyperoxic lung injury has been studied by monitoring the effects of neutrophil depletion on a rat model of pulmonary oxygen toxicity. Pulmonary capillary permeability, assessed using an [125I]albumin lung permeability index (LPI), progressively increased with an increased duration of hyperoxia exposure in normal animals (LPI = 0.43 +/- 0.09 at 24 h; 0.95 +/- 0.17 at 48 h; 1.56 +/- 0.21 at 60 h), despite the absence of any significant tissue or bronchoalveolar lavage evidence of neutrophil infiltration until 60 h of hyperoxia exposure. Neutrophil depletion (using cyclophosphamide) blocked this late neutrophil infiltrate but failed to attenuate lung injury (LPI = 0.38 +/- 0.06 at 24 h; 0.89 +/- 0.16 at 48 h; 1.58 +/- 0.10 at 60 h; all p greater than .05 compared with leucocyte-replete/normal animals exposed to hyperoxia). The temporal dissociation of pulmonary neutrophil accumulation and pulmonary injury and the failure of effective neutrophil depletion to abrogate hyperoxic lung injury indicate that neutrophil polymorphs play no substantive role in the mediation of tissue injury in this model of severe pulmonary oxygen toxicity.

Animals↗
PubMed1988

Role of pulmonary alveolar macrophage activation in acute lung injury after burns and smoke inhalation.

Bronchoalveolar lavage cells from 42 fire victims and from 18 patients who were smokers attending for diagnostic bronchoscopy (controls) were assessed morphologically and by chemiluminescence. 10 of the victims had inhaled smoke only; 15 had cutaneous burns only; and 17 had combined injury. The combined injury group had significant increases in polymorphonuclear leucocytes and macrophages, especially mature forms, compared with controls. These increases were higher than those expected from the individual injuries. The combined injury group had significantly greater spontaneous chemiluminescence than controls, again greater than that expected by the individual injuries. The chemiluminescence response to stimulation by opsonised bacteria was significantly higher in the combined injury group than in controls, but significantly lower than that in the smoke inhalation only group. The size of the alveolar cellular response to smoke and cutaneous burns suggests that lung damage follows from excess release of inflammatory mediators, exhaustion of the reserve of mature phagocytes and consequent reduced ability to fight bacteria, or both.

Acute Disease↗