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Biomedical subjects

D Spencer

Publications and source records attributed to D Spencer.

At least 19 recordsLinked to original sources
PubMed2000

Complete genome sequence of Pseudomonas aeruginosa PAO1, an opportunistic pathogen.

Pseudomonas aeruginosa is a ubiquitous environmental bacterium that is one of the top three causes of opportunistic human infections. A major factor in its prominence as a pathogen is its intrinsic resistance to antibiotics and disinfectants. Here we report the complete sequence of P. aeruginosa strain PAO1. At 6.3 million base pairs, this is the largest bacterial genome sequenced, and the sequence provides insights into the basis of the versatility and intrinsic drug resistance of P. aeruginosa. Consistent with its larger genome size and environmental adaptability, P. aeruginosa contains the highest proportion of regulatory genes observed for a bacterial genome and a large number of genes involved in the catabolism, transport and efflux of organic compounds as well as four potential chemotaxis systems. We propose that the size and complexity of the P. aeruginosa genome reflect an evolutionary adaptation permitting it to thrive in diverse environments and resist the effects of a variety of antimicrobial substances.

Bacterial Proteins↗
PubMed2000

Dimerization-dependent block of the proapoptotic effect of p75(NTR).

The biochemical mechanism by which neurons become dependent on neurotrophins for survival is unknown. We found previously that the common neurotrophin receptor, p75(NTR), is a mediator of neurotrophin dependence and that this effect requires a novel type of domain dubbed a neurotrophin dependence domain. We report here that, in contrast to other proapoptotic receptors such as Fas, apoptosis induction by p75(NTR) requires monomerization, with dimerization inhibiting the effect. Blocking the proapoptotic effect of the monomer by dimerization requires a distinct domain that lies at the carboxyterminus of p75(NTR). These results define a novel type of domain required for inhibiting apoptosis induction by p75(NTR).

Apoptosis↗
PubMed2000

Cloning and characterization of dRFX, the Drosophila member of the RFX family of transcription factors.

The RFX family of transcription factors is characterized by a unique DNA binding domain. Five genes have been isolated in mammals, one gene in Caenorhabditis elegans and in the yeasts Schizosaccharomyces pombe and Saccharomyces cerevisiae. Whereas the roles of the RFX genes are beginning to be understood in yeasts, no clear function has been reported in multicellular organisms, except for RFX5, the most divergent member of the family. To study the physiological role of RFX transcription factors using an alternative multicellular model, we report the isolation and characterization of the Drosophila RFX gene (dRFX). The fruit fly protein shares highly conserved domains with the mammalian factors RFX1 to 3 and is more closely related to this subgroup. It binds DNA with the same target specificity as mammalian factors RFX1 to 3. dRFX is located on chromosome III and we characterized the entire locus. dRFX expression was analyzed during embryogenesis. dRFX mRNAs are detected only in the peripheral nervous system and in the brain of the embryo.

Amino Acid Sequence↗
PubMed2000

Investigation of the child with interstitial lung disease.

Many disorders can affect the pulmonary interstitium in children. Although individual interstitial lung diseases are rare, the range of conditions encountered is wide. Interstitial disease is also seen increasingly as a consequence of the treatment of children having other primary problems including cancer, immunodeficiency and haemotological diseases, as well as in recipients of solid organ and bone marrow transplants. The management and prognosis of individual conditions is highly variable, thus it is essential to search for a precise diagnosis in every patient. High resolution computerised tomography (HRCT) and other less invasive investigations may be helpful in the management of patients. However, it is unusual to be able to make a firm diagnosis without a lung biopsy.

Biopsy↗
PubMed2000

Two liquid medium systems, mycobacteria growth indicator tube and MB redox tube, for Mycobacterium tuberculosis isolation from sputum specimens.

Two manual liquid medium systems, the Mycobacteria Growth Indicator Tube (MGIT) and MB Redox tube systems, were evaluated in comparison to the radiometric BACTEC-460 semiautomated system for recovery of Mycobacterium tuberculosis from sputum specimens. The highest level of recovery, from a total of 77 culture-positive specimens, occurred with the BACTEC-460 system (92.2%), followed by the MB Redox tube (80.5%) and the MGIT (63.6%) systems. The shortest time to detection was observed also among the cultures in BACTEC-460: a mean of 12 days to a growth index (GI) of 10 and 15 days to a GI of 500. The mean times for the other systems were 16 days for the MB Redox tube system and 17.4 days for the MGIT system. The proportion of cultures grown after more than 3 weeks of incubation was only 2.8 or 8.4% in BACTEC-460 (for a GI of 10 or 500) but 17.7% in MB Redox and 22.5% in MGIT. Despite these differences in comparison to the BACTEC-460 system and some differences between the MGIT and MB Redox tube systems, either of the two manual liquid medium systems presents a reasonable alternative to the BACTEC-460 system, especially for laboratories with a limited workload, and a valuable element in the laboratory protocol, in conjunction with solid media, for obtaining rapid detection of growth from about 80% of culture-positive specimens and for better overall recovery of M. tuberculosis.

Automation↗
PubMed1998

Endoscopic intracorporal abdominoplasty: a review of 85 cases.

The specialty of plastic surgery has witnessed an explosion of novel procedures with the advent of endoscopy. Surgeons are making more aggressive attempts to reduce the length of scars and subsequent morbidity associated with traditional "open" procedures. Our purpose is to present a new technique of endoscopic abdominoplasty that has largely replaced traditional "full open" techniques at our institution. Since 1985, 85 patients have undergone a procedure that we call the endoscopic intracorporal abdominoplasty. This technique combines traditional abdominal wall liposuction with endoscopic intracorporal plication of the rectus fascia by using a series of horizontal mattress sutures. The procedure is performed using three 1-cm incisions and a series of midline and lateral skin nicks. These 85 patients were compared with 25 patients who underwent traditional open abdominoplasty with anterior plication of the rectus fascia. Average length of surgery was 127 minutes compared to 149 minutes with the open techniques. Length of hospitalization at our institution was 1 postoperative day compared to an average of 3 days with open techniques. No drains were used with the endoscopic techniques, and all of the open procedures had two drains placed. The perioperative rate of morbidity for the intracorporal abdominoplasty was 15 percent (13 of 85 patients) and with the open abdominoplasty cases it was 24 percent (6 of 25 patients). Our conclusion is that the endoscopic intracorporal abdominoplasty reduces operative scars and effectively plicates the rectus fascia, thereby reducing abdominal wall laxity. It has a rate of morbidity in a skilled laparoscopist's hands no greater than with traditional open abdominoplasty.

Abdominal Muscles↗
PubMed1998

Intracranial hypotension presenting with severe encephalopathy. Case report.

A patient with severe and protracted symptoms from intracranial hypotension is described. The patient's presentation was marked by diffuse encephalopathy and profound depression of consciousness. This case report expands the presently known clinical spectrum of this uncommon and generally benign illness. The clinical and laboratory findings typically observed in the syndrome of intracranial hypotension are outlined. The pathophysiological mechanisms of the phenomenon are briefly discussed. Intracranial hypotension is a potentially severe illness with specific treatments that are distinct from the treatment of most neurological diseases. Three cardinal features--postural headache, pachymeningitis, and descent of midline cerebral structures--should prompt the diagnosis.

Adult↗
PubMed1998

Novel methods for studying new antiepileptic drug pharmacology.

A number of new antiepileptic drugs act by indirect mechanisms and thus produce effects that may not best be measured by traditional blood studies of the drugs and their metabolites. Study of the indirect action of these drugs on GABA-mediated inhibition by microdialysis and nuclear MR spectroscopy has proved more relevant. These new investigative techniques may also prove valuable as compounds affecting glutamate or other excitatory neurotransmitters are developed.

Animals↗
PubMed1997

Enhanced methionine levels and increased nutritive value of seeds of transgenic lupins (Lupinus angustifolius L.) expressing a sunflower seed albumin gene.

With the aim of improving the nutritive value of an important grain legume crop, a chimeric gene specifying seed-specific expression of a sulfur-rich, sunflower seed albumin was stably transformed into narrow-leafed lupin (Lupinus angustifolius L.). Sunflower seed albumin accounted for 5% of extractable seed protein in a line containing a single tandem insertion of the transferred DNA. The transgenic seeds contained less sulfate and more total amino acid sulfur than the nontransgenic parent line. This was associated with a 94% increase in methionine content and a 12% reduction in cysteine content. There was no statistically significant change in other amino acids or in total nitrogen or total sulfur contents of the seeds. In feeding trials with rats, the transgenic seeds gave statistically significant increases in live weight gain, true protein digestibility, biological value, and net protein utilization, compared with wild-type seeds. These findings demonstrate the feasibility of using genetic engineering to improve the nutritive value of grain crops.

Albumins↗
PubMed1997

The Centre for Palliative Care Education and Research.

This article describes the role and function of the Centre for Palliative Care Education and Research at the University of Central England in Birmingham. The authors describe the development of the centre, which is a multidisciplinary venture in collaboration with Cancer Relief Macmillan Fund and palliative care providers throughout the west Midlands. Current educational and research initiatives are identified and some future challenges indicated.

Academies and Institutes↗
PubMed1997

Embryonal adenoma of the kidney: a report of two cases.

Embryonal (metanephric) adenoma of the kidney, like Wilms' tumor, exhibits small monomorphic, blue cells arranged as vague, tubular rosettes. Unlike Wilms' tumor, which requires chemotherapy or multi-modality therapy for optimal management, the available evidence indicates that embryonal adenoma is most likely cured by simple enucleation or nephrectomy. Two women, age 54 (Case 1) and 78 (Case 2), respectively, underwent needle biopsy for a radiologically well circumscribed renal lesion with associated hematuria. The cellular smears contained vague rosette-like arrangement of small, blue cells with scant cytoplasm and evenly distributed, fine, nuclear chromatin. In cell blocks, these cells were arranged as compact, primitive, tubular rosettes or rare, moresolid clusters. Assuming that the absence of undifferentiated blastema and primitive glomeruli represented a sampling error, a diagnosis suggesting of Wilms' tumor was made in Case 1. At nephrectomy, despite extensive sampling, the typical triphasic Wilms' morphology and anaplastic or necrotic areas were not seen. In the presence of architectural monotony, the diagnosis in Case 1 was amended to embryonal adenoma. Case 2 was cytologically diagnosed as embryonal adenoma of the kidney and is being followed conservatively. In our opinion, the presence of monotypic architecture at cytology/histology is very helpful in differentiating renal embryonal (metanephric) adenoma from Wilms' tumor.

Adenoma↗