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Biomedical subjects

B Duffy

Publications and source records attributed to B Duffy.

At least 37 records · Page 2Linked to original sources

Dental problems in the offshore oil and gas industry: a review.

The study of medical evacuation records from offshore installation workers indicates that dental pathology is a significant problem. Dental evacuations (dentivacs) account for the highest single category of medical evacuation (medivacs). Dentivacs result in human suffering and are the cause of many lost man hours for the major oil operators in the United Kingdom. This paper reviews the reporting of dentivacs at Shell Expro over a seven year period and makes some suggestions for the way forward in the handling of offshore dental problems.

Dental Health Surveys↗

What to do about Harry?

This case study about a patient labeled "noncompliant" illustrates a common scenario that home care nurses face in everyday practice. The frustration a nurse experiences when attempting to help a patient who rejects assistance is common and demoralizing and is discussed professionally in this study. A nurse attorney, a nurse manager, and a nurse ethicist respond to the author's case to give insight on the many ways in which this case can be viewed.

Aged↗

Highly purified CD34-positive cells reconstitute hematopoiesis.

PURPOSE: The objective of this study was to characterize CD34+ cell grafts, obtained using a novel technique, from children undergoing autologous bone marrow transplantation (BMT) for cancer therapy. In particular, we wanted to determine if the CD34+ marrow cell grafts generated hematopoietic reconstitution, since a positive result would motivate further development and use of this methodology. PATIENTS AND METHODS: This pilot feasibility clinical trial involved 13 patients < or = 25 years of age with advanced solid tumors, including seven children with neuroblastoma. Harvested bone marrow underwent immunomagnetic CD34+ selection. RESULTS: In three of 13 enrolled patients, low purities of the CD34+ preparations disqualified the use of the CD34+ marrow grafts. Ten patients received myeloablative chemotherapy with etoposide, carboplatin, and cyclophosphamide, then were transplanted with CD34+ marrow grafts. In the 10 patients transplanted with CD34(+)-selected cells, the CD34+ cell purity (nucleated RBCs excluded) in the cell graft preparation was 91% total cell recovery from the starting light-density cells 2.2%, CD34+ cell recovery 38%, colony-forming unit-granulocyte-macrophage (CFU-GM) recovery 23%, and estimated tumor-cell depletion 2.6 logs (medians). The CD34+ marrow grafts administered to these patients contained a median of 2.3 x 10(6) nucleated cells, 1.4 x 10(6) CD34+ cells, and 1.3 x 10(4) CFU-GM per kilogram patient weight. Most patients experienced only the toxicities previously observed with this myeloblative chemotherapy regimen, although two unusual toxicities were observed. All 10 patients transplanted with CD34+ cell grafts engrafted. CONCLUSION: The CD34+ purified grafts were enriched in stem/progenitor cells, with five of these 10 preparations containing > or = 94% CD34+ cells. Engraftment with CD34(+)-purified cell grafts as pure as 99% confirms that autologous CD34+ cells, alone, are sufficient to provide hematopoietic rescue for myeloablated patients. The best purification results were obtained on small marrow harvests from patients with neuroblastoma. The engraftment of highly purified CD34+ cells obtained by this technology and the antitumor effect of the transplant, by which two of 10 poor prognosis patients remain clinically free of tumor, have stimulated further clinical trials.

Adolescent↗

Functional analysis of complement receptor 1 using a new monoclonal antibody, KuN241.

A monoclonal antibody (MAb), KuN241, recognized an antigen present on all monocytes, polymorphonuclear leukocytes (PMNs), B cells, and a subpopulation of T cells. Cell surface expression pattern and immunoprecipitation studies indicated the molecule recognized by KuN241 to be complement receptor 1 (CR1). This was confirmed by sequential immunoprecipitation using E11, a CR1-specific monoclonal, and by immunoprecipitation analysis of a truncated transfection product of CR1. In vivo activation of PBLs for 7 days with pokeweed mitogen (PWM) abrogated surface expression of CR1 on B cells. Overnight culture with phorbol 12-myristate 13-acetate (PMA) downregulated the expression of CR1 detected by KuN241 both on PMNs and monocytes. Addition of MAb KuN241 to purified PMN and monocytes resulted in a transient increase in intracellular calcium ([Ca2+]i). This was blocked by the Fab fragment of MAb KuFc79 directed against the Fc gamma receptor. Further, Fab fragment of KuN241 cross-linked with F(ab')2 goat anti-mouse Ig failed to increase [Ca2+]i levels. Taken together, these results suggested a novel mechanism for transmembrane signaling events by dual binding of KuN241, the Fab region to CR1 and the Fc region of Fc gamma RII.

Animals↗

Short-term outcome of mechanically ventilated infants weighing more than 2499 g at birth: a population based study.

Very little data exist describing the neonatal outcome of infants of birthweight 2500 g or more who require mechanical ventilation. Our aim was to collect population-based data on such infants in New South Wales (NSW), and to monitor their neonatal morbidity, mortality to 1 year of age and the associated risk factors. The study group (NICUS infants) comprised all 341 infants weighing > 2499 g who were admitted to the seven neonatal intensive care units in New South Wales and mechanically ventilated for 4 h or more between 1 January and 31 December, 1987. Two groups of infants emerged: those who were preterm and mostly had hyaline membrane disease, and term and post-term infants for whom the most common problem was 'perinatal asphyxia'. The most important factors associated with dying were a birthweight of over 3499 g (OR = 2.6; CI 1.03-6.6) and a 1 min Apgar score < 4 (OR = 4.8; CI 1.4-16.9). Study group mothers were significantly more likely than all NSW mothers to have had a spontaneous abortion in the previous pregnancy (P < 0.01), a pre-existing medical condition or an obstetric complication in this pregnancy, or a Caesarean section for this delivery (P < 0.001). This is the first population-based study of high-risk neonates without congenital anomalies to clearly document the worsening prognosis associated with a birthweight over 3499 g. Further research should be directed towards identifying prenatal and perinatal factors which might minimize the morbidity and mortality in this group of babies.

Apgar Score↗

ECMO in newborn infants: the New South Wales experience.

Extracorporeal membrane oxygenation (ECMO) has been used at the Prince of Wales Children's Hospital, Sydney for the treatment of newborn infants with life-threatening respiratory or cardiac failure since August 1989. The main indications are that the disease is reversible, the surviving infant is likely to be normal and there is an 80% likelihood of death without ECMO. Eighteen of 19 newborn infants have survived at least 2 months after ECMO. The 15 infants receiving ECMO (nine with meconium aspiration, six with persisting pulmonary hypertension) who did not have a congenital diaphragmatic hernia were normal survivors. One death occurred at 5 months of age from chronic lung disease. Three of four infants with congenital diaphragmatic hernia were discharged following ECMO and appeared normal at 6, 9 and 18 months of age. These results are similar to results from other centres internationally. It appears that ECMO is a useful therapy for near-term newborn infants with otherwise fatal cardiorespiratory failure.

Extracorporeal Membrane Oxygenation↗

Antiidiotypic antibodies to HLA class I alloantibodies in normal individuals: a mechanism of tolerance to noninherited maternal HLA antigens.

Recent reports indicate that 25%-50% of transplant patients exhibit B-cell nonresponsiveness to their noninherited maternal HLA antigens (NIMAs). To test the hypothesis that tolerance of NIMAs is mediated by antiidiotypic antibodies, sera from seven normal human subjects were tested for the capacity to inhibit the reactivity of HLA alloantisera directed to NIMAs. Five of seven sera inhibited (50%-100%) the cytotoxicity of monospecific alloantisera directed to their NIMAs. This inhibition was specific in that antisera directed to third-party HLA antigens were not inhibited. Cytotoxicity inhibition by normal sera was selective for antisera directed to HLA-B locus antigens. Absorption with an antibody specific for an HLA class I framework determinant eliminated the inhibitory activity of three of the five sera, suggesting that the inhibition was mediated by soluble HLA antigens in these cases. However, two of the sera retained inhibitory activity following soluble antigen depletion, suggesting that, in these cases, inhibition is mediated by antiidiotypic antibodies. This hypothesis was confirmed by purifying the immunoglobulin (Ig) fraction of one of these sera by anti-Ig affinity chromatography; the column eluate (Ig fraction) but not the effluent (Ig-depleted serum) was capable of inhibition. These data are consistent with the hypothesis that tolerance of NIMAs is mediated, at least in part, by antiidiotypic antibodies.

Antibodies, Anti-Idiotypic↗

Epidural catheters.

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Anesthesia, Epidural↗

The effect of feeding route (i.v. or oral) on the protein metabolism of the neonate.

We have examined the effect of the route of feeding (intravenous versus enteral) on the protein metabolism of postsurgical human neonates. Twelve infants, birth weight 2.5 +/- 0.2 kg, gestational age 38 +/- 1 wk, were studied. The IV study was carried out 1-4 days after surgery at a postnatal age of 14 days and a weight of 2.6 +/- 0.2 kg. The repeat (oral) study was carried out 16 days later. Protein intakes were similar during both studies (2.7 g/kg/d). Energy intakes were within the requirement range for age and feeding route and were: IV, 85 +/- 4 kcal/kg/d; oral, 111 +/- 7 kcal/kg/d. Whole body protein metabolism was studied using a continuous infusion of 15N-glycine. Amino nitrogen flux, protein synthesis, and breakdown were 40% higher during the enteral than the IV studies (p less than 0.001). Skeletal muscle degradation was investigated by measuring urinary excretion of creatinine and N-T-methylhistidine. No differences were detected due to feeding route. We suggest that the differences seen in whole body protein turnover rates reflect the rapid growth and development of the gut in the enterally (rather than the IV) fed infant.

Creatinine↗

The effects of surgery on the nitrogen metabolism of parenterally fed human neonates.

Nitrogen retention and rates of whole body amino nitrogen flux, protein synthesis, and breakdown were measured in 18 neonates during the 72 h immediately postsurgery. The infants were all intravenously fed with a crystalline amino acid source (Vamin), glucose, and Intralipid The infants were divided into two groups based on amino acid intake: either 2.3 SD 0.4 g or 3.9 SD 0.5 g/kg/day. Nonprotein energy intakes were similar and averaged 81 kcal/kg/day. Group A (n = 11) retained 145 SD 110 mg N/kg/day, whilst group B (n = 7) retained 315 SD 93 mg N/kg/day (p less than 0.001). There were no differences seen in flux, synthesis or breakdown. However, group B had significantly higher net protein synthesis rates (synthesis-breakdown) (p less than 0.01). The improved nitrogen utilization in group B was achieved principally by a reduction in endogenous protein breakdown. There were no differences between the two groups in urinary creatinine or 3-methylhistidine excretion. Since these two parameters reflect skeletal muscle turnover the differences between groups in nitrogen retention and turnover appear to be mediated through visceral protein.

Amino Acids↗

The meaning of cognitive impairment in the elderly.

In order to determine the meaning of cognitive impairment in community dwelling elderly, 3,481 adults were interviewed in their homes using the Mini-Mental State Examination. Ninety-six per cent of the population aged 18-64 scored 23 or higher, whereas 80 per cent of the population 65 and over scored 23 or higher. Individuals with low scores were suffering from a variety of psychiatric disorders including dementia. Thirty-three per cent of the elderly population scoring in the range of 0-23 had no diagnosable DSM-III condition. Prevalence of dementia from all causes was 6.1 per cent of the population over age 65. Two per cent of the population over age 65 were diagnosed as having Alzheimer's disease.

Adolescent↗