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Biomedical subjects

D J Alexander

Publications and source records attributed to D J Alexander.

At least 19 recordsLinked to original sources
PubMed1995

Combination therapy using adrenaline and heater probe to reduce rebleeding in patients with peptic ulcer haemorrhage: a prospective randomized trial.

A prospective randomized trial was performed to assess the efficacy of the combined therapy of endoscopic injection of adrenaline and heater probe application in the management of patients with major peptic ulcer haemorrhage. Some 153 consecutive patients were randomized to receive either local injection of adrenaline (1:10,000) followed by heater probe thermocoagulation (74 patients) or no endoscopic treatment (79 patients). The two groups were well matched with regard to age, haemoglobin concentration on admission, non-steroidal anti-inflammatory drug usage and endoscopic findings. More patients in the treatment group were in shock on admission (21 versus 13). Initial haemostasis was achieved in all patients randomized to endoscopic therapy. Rebleeding occurred in fewer treated than control patients (five versus 16, P = 0.01). The treated group also had fewer deaths (zero versus two) and requirement for operation (two versus six). The results show that the combination of sclerotherapy with adrenaline and subsequent thermocoagulation reduces the rate of rebleeding in peptic ulcer haemorrhage.

Adult↗
PubMed1995

Serological studies of influenza viruses in pigs in Great Britain 1991-2.

Samples from a sow serum bank representative of the pig population of Great Britain collected during 1991-2, were examined for antibodies to influenza A, B and C viruses, using viruses which had been isolated from a variety of hosts. For influenza A viruses there was evidence of the continued circulation of classical swine H1N1 virus (26%) seroprevalence), and human H3N2 viruses (39%) which are antigenically most closely-related to A/Port Chalmers/1/73 virus. In addition antibodies were detected to A/swine/England/201635/92 (8%), a strain of H3N2 virus which appears to have arisen by antigenic drift from conventional H3N2 swine strains. Specific antibodies (2%) were detected to an H1N1 virus (A/swine/England/195852/92) related most closely to avian H1N1 strains. In tests with human H1N1 and H3N2 viruses, excluding isolates from pigs, the highest seroprevalence was detected to the prevailing strains from the human population. Serological tests with avian H4 and H10, human H2, equine 1 and 2 influenza A viruses were all negative. Seven pigs seropositive by haemagglutination-inhibition, virus neutralization and immunoblotting assays for antibody to influenza B virus, were randomly distributed geographically suggesting that influenza B viruses may be transmitted to pigs but fail to spread. The seroprevalence to influenza C viruses was 9.9% indicating that these viruses are widespread in pigs. These results provide further evidence that the pig can be infected by a number of influenza viruses, some of which may have significance in the epidemiology of human influenza.

Animals↗
PubMed1994

Right atrial electrocardiography: a technique for the placement of central venous catheters for chemotherapy or intravenous nutrition.

Central venous catheters used for chemotherapy are usually sited so that the catheter tip lies in the superior vena cava. This study evaluated right atrial electrocardiography as a method of accurately placing the catheter tip in 34 patients over a period of 22 months. An electrocardiograph adaptor was connected to the catheter and the tip advanced into a central vein until a biphasic P wave was identified. In 31 of 34 patients the characteristic P wave changes were observed and the position of the catheter tip confirmed by screening to be in the superior vena cava. Right atrial electrocardiography is an accurate, reliable and rapid method of positioning the tip of a central venous catheter, and avoids or reduces exposure to radiation.

Catheterization, Central Venous↗
PubMed1994

Evaluation of the molecular basis of pathogenicity of the variant Newcastle disease viruses termed "pigeon PMV-1 viruses".

The amino acid sequence at the F2/F1 cleavage site was determined for 15 strains of the so-called pigeon PMV-1 (PPMV-1) variant of Newcastle disease virus (NDV) which showed close antigenic identity, determined by their reactions with a panel of 28 monoclonal antibodies, but considerable variation in their pathogenicity for chickens. Thirteen of the isolates possessed the motif 112G-R-Q-K-R-F117. This motif was seen for one virus which had initially low pathogenicity and remained unaltered when virulence of the virus for chickens was increased by bird to bird passage. The two other viruses had the sequence 112R-R-Q-K-R-F117 at the cleavage site which is more typical of virulent viruses, however, pathogenicity index tests indicated that these isolates were of moderate and low pathogenicity. The nucleotide sequence coding for the HN/HN0 extension region was determined for two of the PPMV-1 isolates. In both cases a stop codon was present indicating that the product for these viruses would be HN571. We conclude that the wide variation in pathogenicity of the variant PPMV-1 for chickens is not related to variation in the amino acid motif at the F2/F1 cleavage site nor due to production of HN0 which may also influence pathogenicity. The high virulence of some of the viruses examined confirms that a double pair of basic amino acids in the region of the F2/F1 cleavage site is not necessary for the full expression of virulence.

Amino Acid Sequence↗
PubMed1994

Deduced amino acid sequences of the haemagglutinin of H5N1 avian influenza virus isolates from an outbreak in turkeys in Norfolk, England.

The deduced amino acid sequences of the haemagglutinins of avian influenza viruses, isolated from an outbreak in turkeys in Norfolk, England in 1991/92, were determined by PCR amplification and cycle sequencing. Both the highly pathogenic and avirulent isolates had the same cleavage site sequence with multiple-basic amino acids, which normally would be expected only for the former. Clones derived by plaque picking from the highly pathogenic isolate ranged from low to very high pathogenicity in vivo and these, and the original isolates, showed nucleotide and amino acid variation at one or more of five possible sites, none of which were at the cleavage site. None of these site variations correlated with pathogenicity, suggesting that the factor responsible for the suppression of the expected effects of the multiple-basic amino acid haemagglutinin cleavage site in the avirulent isolate may not have been part of the haemagglutinin amino acid sequence.

Amino Acid Sequence↗
PubMed1992

Characterisation of an antigenically unusual virus responsible for two outbreaks of Newcastle disease in the Republic of Ireland in 1990.

Antigenic characterisation of two highly virulent virus isolates from outbreaks of Newcastle disease on two closely connected farms in County Monaghan, Republic of Ireland, in 1990 showed the viruses to be indistinguishable but unlike other Newcastle disease viruses so far tested. However, they appeared to be antigenically closest to avirulent viruses isolated from waterfowl from several countries and from chickens in Northern Ireland in 1986. Despite the antigenic differences, chickens vaccinated with a live commercial Hitchner B1 vaccine were protected against intramuscular challenge with one of the virulent isolates.

Animals↗
PubMed1992

Influence of catheter type on occurrence of thrombophlebitis during peripheral intravenous nutrition.

To reduce the likelihood of thrombophlebitis during intravenous feeding through a peripheral vein, the osmolality of the solution is usually reduced by disproportionately raising the lipid content and lowering the carbohydrate, electrolyte, and aminoacid concentrations. The possibility that delivery system rather than feed is the main influence on the development of thrombophlebitis was examined in a randomised comparison of a fine-bore silicone catheter against a short 'Teflon' cannula. The nutrient solution given through a peripheral vein was a standard feed used for infusion into a central vein (osmolality 1250 mOsmol/kg, 13 g nitrogen, 200 g glucose [800 kcal], and lipid emulsion [1000 kcal]). 27 patients received the infusion through a fine-bore silicone rubber catheter (diameter 23 G, length 15 cm) and 23 through a teflon catheter (diameter 20 G, length 3.2 cm). The median duration of feeding was 5 days in each of the two groups. Thrombophlebitis developed in all patients in the teflon group but in only 2 (7%) of the silicone group. The first silicone catheter for a patient lasted a median of 128.5 h, compared with 40 h for the first teflon cannula (p less than 0.001). The results show that when a nutrient solution of osmolality 1250 mOsmol/kg is delivered through a peripheral vein with an ultrafine-bore silicone catheter, the risk of thrombophlebitis is low. For many patients intravenous feeding may thus be given through a peripheral instead of a central vein without compromising the nutritional adequacy of the feed.

Adolescent↗
PubMed1992

Treatment of acute pancreatitis caused by calculous obstruction of the pancreatic duct by ultrasound-guided percutaneous drainage.

In a small percentage of patients with acute pancreatitis, recurrent attacks of pain and hyperamylasaemia occur when feeding is commenced. Recurrences of this type may occur because the pancreas is still swollen and inflamed, and indicate the need for a longer period of "pancreatic rest" before food is introduced. Alternatively, they may reflect the presence of "mechanical" factors leading to the recurrent pancreatitis, such as a gallstone in the common bile duct, a pseudocyst of the pancreas, or pancreatic duct obstruction. Successful resolution of the pancreatitis may require treatment of underlying causative factors. A stone in the pancreatic duct (probably a gallstone) was found to be the cause of recurrent acute pancreatitis in an elderly patient with severe cardiovascular disease, who was unfit for surgery. Pancreatitis settled after percutaneous drainage of the pancreatic duct, the technique described.

Acute Disease↗
PubMed1992

Avian paramyxovirus serotype 1 (Newcastle disease virus)--infections in falcons.

From eight falcons and one pigeon which died from NDV over a period of 15 months in Dubai, United Arab Emirates, PMV-1 viruses were isolated on quail embryo cell cultures. The identification of all 9 strains were achieved with the haemagglutination inhibition test against polyclonal chicken PMV-1 antiserum, against mouse monoclonal antibodies as well as with the immunoperoxidase test. Intracerebral pathogenicity index and intravenous pathogenicity index tests were also carried out. Although the virus isolates in this study fell into two distinct groups, the overall clinical symptoms displayed by the falcons tailed to demonstrate any trends or specificity unique to a group. The isolate obtained from a pigeon was similar to the isolates from one group of the falcons and showed no identity with the pigeon variant virus.

Animals↗
PubMed1992

Characterisation of Newcastle disease viruses isolated in India.

Eleven Newcastle disease virus (NDV) isolates obtained from outbreaks of disease in chickens (9) and Japanese quail (2) in Tamil Nadu, India were characterised in pathogenicity tests, antigenically, using mouse monoclonal antibodies (MAbs), and other established tests devised to distinguish between different strains. All 11 isolates were shown to be highly virulent for chickens. In indirect immunoperoxidase tests used to assess the ability of a panel of 28 MAbs to bind to infected cell cultures, 10 of the isolates showed an identical reaction pattern, the other isolate (No. 4) failed to react with one MAb which bound to cells infected with the other isolates. Isolates 9 was unstable at pH 3 while the other 10 were stable. All other properties were shared by the 11 isolates.

Animals↗
PubMed1992

The immunology of virus infections.

In order to describe the complex virus-host relationship the authors review the viral mechanisms of infection and viral replication as well as the basic pattern of the immune responses. The delicate balance of the infection-immunity equation is complicated by the instability of both entities. The better understanding of these factors provides a rationale for the therapeutic counteraction of virus infections, reducing the likelihood of viral exposure becoming clinical viral infection.

Animals↗
PubMed1991

Evaluation of relationships between avian paramyxoviruses isolated from birds of the family Columbidae.

The prototype virus for the PMV-7 serotype of avian paramyxoviruses, PMV-7 dove Tennessee/4/75 (Tn 4) and five other isolates obtained from birds of the Columbidae family, which had been shown to be distinct from PMV-1 serotype, were tested for antigenic relationships between themselves and to other avian paramyxoviruses. By serological tests and analysis of structural polypeptides the viruses appeared to be distinct from other avian paramyxoviruses. One isolate appeared to be very closely related to Tn/4. Three other isolates showed only minor relationships to these two but were very closely related to each other. However, the sixth virus, pigeon Japan/Otaru/76, showed high levels of homology in haemagglutination inhibition tests and at least one line of identity in immunodoublediffusion tests with all five of the other isolates.

Animals↗