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Biomedical subjects

D J Brown

Publications and source records attributed to D J Brown.

At least 19 recordsLinked to original sources
PubMed1995

Identification of two binding proteins for halogenated aromatic hydrocarbons in the hard-shell clam, Mercenaria mercenaria.

Earlier studies have reported an unusually high incidence of gonadal tumors in marine bivalves in areas of potentially high exposure to herbicides including 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophe-noxyacetic acid. Some herbicides can be contaminated by halogenated aromatic compounds including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Most of the effects of planar halogenated aromatic compounds, including carcinogenic effects in vertebrates, appear to be mediated through binding to the aryl hydrocarbon receptor. The current study investigated whether halogenated aromatic hydrocarbon-binding proteins are present in the marine bivalve, Mercenaria mercenaria. We used the TCDD photoaffinity analog 2-azido-3-[125I]-iodo-7, 8-dibromodibenzo-p-dioxin to detect the presence of two proteins (28 and 39 kDa) in cytosols prepared from M. mercenaria that specifically bound this ligand. Expression of these proteins is tissue-dependent with the highest concentrations being observed in gill and gonadal tissue. Gonadal tissue also exhibited gender-specific expression with female clams exhibiting higher levels of the 39-kDa protein. Gender-and tissue-specific expression are consistent with the hypothesis that these proteins might be involved in the carcinogenic response observed in clams exposed to herbicides.

Affinity Labels↗
PubMed1995

Sequence of RNA 2 of a nematode-transmissible isolate of tobacco rattle virus.

Tobacco rattle virus (TRV) isolate PPK20 is transmitted by Paratrichodorus pachydermus nematodes. The factor(s) determining vector transmissibility has been shown to be located on TRV RNA 2. Sequence determination revealed that PPK20 RNA 2 contains three open reading frames encoding the coat protein (cp) and proteins with molecular masses of 29.4 and 32.8 kDa. The 29.4 and 32.8 kDa protein-coding genes showed no significant sequence similarity to any other known tobravirus gene. A full-length cDNA of PPK20 RNA 2 cloned between the 35S promoter and nos terminator infected plants when co-inoculated with PPK20 RNA 1. Deletions in the reading frames of the 29.4 and 32.8 kDa proteins revealed that these sequences are dispensable for replication of PPK20 RNA 2 in plants. Subgenomic RNAs for translation of cp and the putative 29.4 and 32.8 kDa proteins were detected in infected leaves. The possible role of PPK20 RNA 2 non-structural genes in TRV vector transmission is discussed.

Amino Acid Sequence↗
PubMed1995

Sequence comparison of RNA2 of nematode-transmissible and nematode-non-transmissible isolates of pea early-browning virus suggests that the gene encoding the 29 kDa protein may be involved in nematode transmission.

A cDNA clone containing the complete coding region of RNA2 of the newly described TPA56 isolate of pea early-browning virus (English serotype, PEBV-E) has been obtained. A plasmid (pFLA56) containing this clone together with the 5' and 3' non-coding regions of PEBV isolate SP5 (the type isolate of PEBV-E) and flanked by the CaMV 35S promoter and NOS terminator is infectious when co-inoculated onto plants with pCaN1, an infectious clone of PEBV SP5 RNA1. Virus containing RNA2 derived from the cDNA clone of the TPA56 isolate is transmitted by Trichodorus primitivus nematodes, whereas virus containing RNA2 from a clone of the SP5 isolate is not transmitted. Sequencing revealed 11 differences out of 3374 nucleotides between the transmissible TPA56 and non-transmissible SP5 clones. However, only three of the base changes affected the amino acid sequences of virus gene products. A single, conservative amino acid change was present in the virus coat protein. Two non-conservative changes occurred in the protein of molecular mass 29.6 kDa expressed from an open reading frame located down-stream of the coat protein gene, suggesting that it has a function in nematode transmission and that changes in this protein prevent vector transmission of the SP5 isolate of PEBV.

Animals↗
PubMed1995

The effect of levcromakalim (BRL 38227) on bladder function in patients with high spinal cord lesions.

The effects of the potassium channel opener levcromakalim (BRL 38227) 7.5 micrograms kg-1 were examined on urodynamic variables and blood pressure during inflow and voiding cystometry in six high spinal cord lesion patients. Levcromakalim administration significantly increased the duration of bladder contraction (197 +/- 128 s to 267 +/- 167 s, P < 0.05) and also reduced blood pressure (126 +/- 13/67 +/- 9 mm Hg to 104 +/- 25/52 +/- 12 mm Hg) but was without effect on other urodynamic parameters. Because of concerns about hypotensive responses, further studies involving higher doses of levcromakalim should be considered only if the drug was administered intravesically.

Adult↗
PubMed1994

Opinions of general practitioners in Nottinghamshire about provision of intrapartum care.

OBJECTIVE: To examine the beliefs of general practitioners concerning intrapartum care. DESIGN: Postal questionnaire survey. SUBJECTS: All general practitioners with patients in Nottinghamshire Family Health Services Authority in September 1993. MAIN OUTCOME MEASURES: General practitioners' current involvement in maternity care, and beliefs on intrapartum care. RESULTS: Of 694 general practitioners sent questionnaires, 550 (79.2%) replied. 529 of these were on the obstetric list; 437 had not attended a delivery in the past 12 months; 36 had attended two or more; 358 general practitioners did not wish to provide more intrapartum care; 349 did not feel competent to do so. Reasons for not wanting to provide intrapartum care included current workload (453), disruption to personal life (407), and the fear of litigation (377). General practitioners who already booked women for home delivery were more likely to wish to do more deliveries (62/42 v 61/316, chi 2 = 85.3; P < 0.0001) and to have more positive attitudes towards increasing women's choice in maternity care (90/22 v 195/151, chi 2 = 227; P < 0.0001). CONCLUSIONS: The involvement of general practitioners in intrapartum care in Nottinghamshire is low, and most general practitioners are unwilling to increase their role. However, general practitioners who already book for home delivery are keen to do more.

Attitude of Health Personnel↗
PubMed1994

Collection of semen from men in acute phase of spinal cord injury.

In chronic spinal cord injury, semen obtained by assisted ejaculation is usually abnormal. We have assessed electroejaculation early after injury in seven patients. There were no adverse effects. Initial samples contained few or no spermatozoa but as patients emerged from spinal shock, semen improved and five had specimens cryopreserved. Thereafter sperm motility and viability decreased towards the pattern of chronic spinal cord injury by day 16. Cryopreservation was not possible in one patient with many medical complications and another who started electroejaculation 15 days after injury. Semen storage within the first 2 weeks after spinal cord injury is recommended for future fertility treatment.

Acute Disease↗
PubMed1994

Remodelling of a displaced phalangeal neck fracture.

Phalangeal neck fractures are uncommon in children. When these injuries to the proximal and middle phalanges are displaced and not treated operatively the fracture may heal in a malunited position with loss of motion at the IP joint. Remodelling in the area of the phalangeal neck is thought to be reduced because of its distance from the physis. In cases of malunion osteotomy of the phalangeal neck may be required to restore anatomy and motion. A case is described which demonstrates complete remodelling of a displaced middle phalangeal neck fracture in a child and recovery of a normal range of motion without operative intervention.

Bone Remodeling↗
PubMed1994

Clonal lines of Salmonella enterica serotype Enteritidis documented by IS200-, ribo-, pulsed-field gel electrophoresis and RFLP typing.

Sixty-two selected strains of Salmonella serotype Enteritidis of 33 phage types (PTs), and one strain classified as RDNC, were characterised by four different chromosomally based typing methods to elucidate genetic relationships among strains of different phage types. Based on IS200-hybridisation patterns, two major groups, containing strains of the most commonly encountered phage types, and six minor groups (seven with the RDNC strain included) were observed. IS200 pattern was a stable epidemiological marker in strains of all phage types except PT 6a and 14b. Ribotyping separated strains of the phage types into one major and five minor groups; the pattern of the RDNC strain was not seen with other strains. More than one ribotype was observed among strains of Enteritidis PTs 6, 7, 14b and 21. By pulsed-field gel electrophoresis, strains of 21 of the 33 phage types formed one large cluster when bands > 125 kb were used as the criterion for separation. Among strains belonging to PTs 1, 6, 7 and 14b, more than one pattern was observed by this method. By probing with five random cloned fragments of the Enteritidis chromosome, strains from 27 of 31 phage types examined showed the same hybridisation pattern. With the combined use of four genotypic methods, two groups of strains, representing eight and seven of 33 Enteritidis phage types, were formed; these two groups may be considered as the main evolutionary lines of Enteritidis. Strains of the remaining phage types, and the RDNC strain, belonged to separate groups.

Animals↗
PubMed1994

Stability of plasmids in five strains of Salmonella maintained in stab culture at different temperatures.

Four strains of Salmonella berta and one of Salm. enteritidis were stored as stab cultures in sugar-free agar at 5 degrees, 22 degrees and 30 degrees C and in 15% glycerol at -80 degrees C. The stability of the plasmid profiles in each of the strains was monitored over a period of 2.5 years. Plasmid profiles were stable in all strains stored at -80 degrees C, and only six of 450 colonies examined from strains kept in sugar-free agar at 5 degrees C had lost plasmid molecules. Seventy of 440 colonies from stab cultures that were kept at 22 degrees C, and 71 of 440 colonies at 30 degrees C showed changed plasmid profiles. The total number of plasmids lost increased with time, and occasionally, more than one plasmid molecule was lost in the same strain. The virulence associated plasmid of Salm. enteritidis was remarkably stable as it was maintained in all colonies examined at all temperatures investigated. Likewise, no change in SmaI restriction profile was observed in this plasmid molecule at any temperature.

Plasmids↗
PubMed1994

Theileria annulata sporozoite targets.

Bovine peripheral blood mononuclear cells (PBM) infected in vitro with Theileria annulata sporozoites have previously been characterized as MHC class II+ mature macrophages. The ability of T. annulata sporozoites to infect different subpopulations of MHC class II+ bovine monocytes was investigated. Cells were labelled with monocyte specific monoclonal antibodies (MoAb) and isolated using magnetic cell sorting (MACS). Sporozoites infected both immature and mature monocytes, but more readily infected the mature population. A potential ligand for sporozoite entry is the elastin receptor which is expressed mainly on the immature population of monocytes and not on B cells or T cells. T. annulata sporozoites infected elastin receptor positive and negative cell populations equally well. Infected immature cells lost the expression of elastin receptors and the immature marker, subsequently expressing the mature marker. All monocytes lost the expression of CD14 (the LPS receptor) upon infection with sporozoites. The infection of specific populations and subsequent alterations in phenotype may alter the function of these cells and play an important role in disease pathogenesis.

Animals↗
PubMed1992

A study of the alpha-1 adrenoceptor blocker prazosin in the prophylactic management of autonomic dysreflexia in high spinal cord injury patients.

The ability of the alpha-1 adrenoceptor antagonist, prazosin, to reduce the severity and duration of episodes of autonomic dysreflexia was studied in cervical and high thoracic spinal cord injury patients with documented episodes of autonomic dysreflexia. Sixteen patients participated in a double blind parallel group study comparing prazosin 3 mg b.d. with placebo given for 2 weeks. Both groups were matched for age, sex and baseline severity of autonomic dysreflexia episodes. Prazosin was well tolerated and did not produce a significant lowering of resting blood pressure. Compared to baseline measurements, patients allocated to prazosin therapy were found to have fewer severe episodes of autonomic dysreflexia and during these episodes to have significant reductions in average rise in systolic and diastolic blood pressure, symptom duration and requirement for acute antihypertensive medication. The severity of headache during individual autonomic dysreflexia episodes was also diminished with prazosin therapy. No symptom parameter was significantly altered by placebo therapy. It is concluded that prazosin is superior to placebo in the prophylactic management of autonomic dysreflexia and that these findings are consistent with suggestions that alpha-1 adrenoceptors play an important role in the pathogenesis of this syndrome.

Adolescent↗
PubMed1992

Salmonella enterica: infection, cross infection and persistence within the environment of a broiler parent stock unit in Denmark.

A total of three hundred and ninety nine isolates of Salmonella enterica were recovered from 3106 cloacal swab cultures, chicken carcasses and environmental samples taken from a broiler breeding farm over six successive generations. S. enterica serovars Berta (S. Berta), 4,12:b:-, Taksony, Binza and Typhimurium were identified. One hundred and seventy one strains of S. Berta were analysed by plasmid profiling to determine the epidemiological relationships between isolates from each generation and from each house section of the production unit. All isolates contained plasmids; plasmids of eleven different molecular weights were identified. Eighteen different plasmid profiles were identified throughout the observation period. An increase in the diversity of plasmid profiles in each successive generation, the restriction of particular plasmids to particular houses and their persistence within that house were taken to indicate that contamination within the unit was due to persistence and cross-infection rather than to a reintroduction of serovar Berta into new generations of stock.

Animals↗
PubMed1992

Biochemical and molecular characterization of Salmonella enterica serovar berta, and comparison of methods for typing.

Strains of Salmonella enterica serovar berta (S. berta) from Denmark and seven other countries have been characterized with the aim of developing a rational typing strategy in connection with outbreak investigations. Biotyping divided the strains into H2S-positive (90%) and H2S-negative (10%) biovars. Six percent of the strains were resistant to one or more antimicrobial agents. Eighty-eight percent of the strains carried plasmids and 52 different plasmid profiles were recognized. Six of the common plasmid sizes in these profiles were shown by restriction enzyme analyses to contain more than one plasmid species. More than 90% of the strains had the same ribotype with the restriction enzymes Sma I and EcoR I and the same whole cell protein profile. Outer membrane protein profiles and isoenzyme profiles were identical in all S. berta analysed. Plasmid profiling in combination with restriction enzyme analysis of plasmids seemed to be the most rational typing strategy for S. berta. The results indicated that S. berta strains regardless of geographical source or host are possibly clonal in nature.

Animals↗
PubMed1992

Suicide following acute traumatic spinal cord injury.

The rate of suicide following spinal cord injury has not been extensively studied but appears to be greater than in the general population. Six patients who died by suicide, from a total of 342 patients who were treated for acute spinal cord injury over a 5 year period are described. Clinical features shared by this group of patients included being male; having schizoid, depressive or narcissistic personality traits; alcohol or drug abuse; family or significant others favouring death as a preferred option; and the development of significant depression.

Acute Disease↗