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Biomedical subjects

P G Wright

Publications and source records attributed to P G Wright.

At least 19 recordsLinked to original sources
PubMed1989

Pulsatile flow index for qualitative measurements of blood flow with duplex ultrasound. An experimental study.

We determined the accuracy of Doppler blood flow measurements in an experimental investigation using a tissue-simulating phantom, pulsatile flow pumps and heparinized blood. A new index for qualitative assessment of blood flow, the pulsed flow index (PFI) is described. The PFI takes advantage of the area under the flow velocity curve between the true zero line and the diastolic baseline. Under conditions of continuous flow, the PFI ranged from 0.82 to 0.94 (mean value 0.90). The PFI was found to be relatively independent of the transducer/vessel angle (+/- 8%) and the inter/intra-operator variation was small (+/- 7.5%, or +/- 7%, respectively).

Blood Flow Velocity↗
PubMed1987

Peripheral nerve conduction in the fruit bat with nitrous oxide induced vitamin b12 deficiency.

Fruit bats Rousettus aegyptiacus were depleted of vitamin B12 by exposure to the gas nitrous oxide (N2O-oxygen, 1:1 v/v) for 57-80 days. Conduction velocities along the fastest fibres of the ulnar nerve, as well as the first and second peaks, were similar in control and vitamin b12 depleted animals. It is concluded that neurological impairment resulting from depletion of vitamin B12 by N2O does not involve significant impairment of ulnar nerve function in this species.

Animals↗
PubMed1987

Blood gas pH and pulmonary response to the inhalation of low osmolar contrast media iopamidol and ioxaglate.

Effects of inhalation of diluted low-osmolar ionic ioxaglate and nonionic iopamidol 200 water-soluble radiographic contrast media on neonatal pig lung were evaluated. Our purpose was to assess the suitability of these substances for the radiologic investigation of upper gastrointestinal problems in human neonates in whom aspiration may occur. We used two-week-old baby piglets weighing 2.5-3.5 kg as the experimental model because they are similar in weight and size to a human neonate. The effects of intratracheal instillation of isosmolar contrast media were evaluated using the parameters of (1) blood gas exchange, (2) clinical status, (3) radiology, and (4) histopathology. The piglets showed no clinical or radiologic abnormality; blood gas exchange, initially impaired, rapidly returned to normal. Long-term (four days) follow up showed mild, self limiting but persistent infiltrates in the lungs at histology. We conclude that these diluted contrast media are suitable for upper gastrointestinal examination in neonates.

Administration, Inhalation↗
PubMed1987

Sonographic evaluation of the kidney following extracorporeal shock wave lithotripsy.

We investigated the value of real-time sonography for determination of pelvicaliceal dilatation 24-48 h after extracorporeal shock wave lithotripsy (ESWL) in 369 patients (419 treated kidneys). A varying degree of hydronephrosis was present in 121/419 (29%) kidneys. Fragmented stones post-ESWL were demonstrable in 346/419 kidneys (82%), but were missed by ultrasound in three kidneys (less than 1%). In four kidneys (1%), stone fragments which were shown to be present by ultrasound were not detectable on radiographs. In 25/419 kidneys (6%), evidence of renal trauma caused by ESWL was demonstrated by ultrasound. The most important incidental finding was a small renal cell carcinoma of the contralateral (untreated) kidney.

Diagnosis, Differential↗
PubMed1985

The validity of the Carlson Psychological Survey with adolescents.

The present study examined the factorial and predictive validity of the Carlson Psychological Survey with male adolescent offenders (n = 350). Factor analysis revealed that, in general, the Carlson is well represented by five scales. Of the four content scales, Antisocial Tendencies proved to be the best of a variety of predictors of institutional adjustment. Thought Disturbance and Self-Depreciation were unrelated to staff ratings on the Behavior Problem Checklist 'Personality Problem' Scale; however, they were positively correlated with the Social Anxiety and Withdrawal scales of the Jesness Inventory. The pattern of these correlations, as well as those between Antisocial Tendencies and the behavioral data, suggest that the Carlson Psychological Survey may be a good indicator of internalizing versus externalizing behavioral and attitudinal styles.

Acting Out↗
PubMed1984

Organic phosphates increase the solubility of avian haemoglobin D and embryonic chicken haemoglobin.

The isolated minor haemoglobin fractions (haemoglobin D) of ostrich, chicken and duck haemoglobin, which constitute about 30% of total intracellular haemoglobin, form crystalline aggregates upon deoxygenation at physiological temperature, ionic strength and pH and at haemoglobin concentrations even well below those present in the red cell. The aggregation is reversed by oxygenation, and can be inhibited by addition of organic phosphates or the corresponding major haemoglobin fraction in a stoichiometric ratio of 1:1. Embryonic haemoglobin from chicken has similar characteristics with respect to its solubility. The results indicate close functional homology of alpha D and embryonic pi-chains as well as a novel role for organic phosphates in the regulation of haemoglobin function.

Adenosine Triphosphate↗
PubMed1984

Sonographic diagnosis of furosemide-induced nephrocalcinosis in newborn infants.

In three newborn infants who had received furosemide for a variety of indications, strongly increased echogenicity in the pyramids of the renal medulla was seen on ultrasonography. In one infant the changes were unilateral, the contralateral kidney being nonfunctional because of probable renal artery thrombosis. One infant died and medullary nephrocalcinosis was confirmed post mortem radiologically as well as by computed tomography and anatomic-histologic examination of the kidneys.

Female↗
PubMed1984

Blood composition in culled elephants and buffaloes.

Blood composition of succinyldicholine culled elephants and buffaloes was compared with that of undisturbed animals shot in the brain. The results show statistically significant differences in a number of variables including plasma ACTH and cortisol concentrations. The observed changes are attributed to stress induced by a combination of herding and darting with succinyldicholine and asphyxia. Extrapolation from blood oxygen tensions suggests that this stress may be perceived for an undetermined period which is probably longer in elephants than buffaloes.

Acid-Base Equilibrium↗
PubMed1983

Failure to secrete immunoreactive insulin by rats fed a low protein diet.

Rats fed a 6% protein diet for 14 weeks showed a normal glucose tolerance but failed to release immunoreactive insulin (IRI), following iv glucose. Furthermore the isolated perfused pancreas of the rats fed the 6% protein diet secreted eleven times less IRI than the isolated pancreas prepared from the rats reared on an 18% protein diet when both were subjected to the same glucose challenge. This difference occurred despite the fact that the total IRI content of the pancreas' was not significantly different between the two groups. In the protein-malnourished rats it is suggested that the normal glucose tolerance response, despite the failure to release a concommitant amount of IRI, may indicate increased sensitivity to IRI or may be due to the secretion in these animals of a biologically active insulin, which shows no immunological cross-reactivity with pancreatic insulin. Alternately there may be increased peripheral glucose utilisation in the low protein rats.

Animals↗
PubMed1983

[Primary structures of the alpha and beta chains from the major hemoglobin component of the ostrich (Struthio camelus) and American rhea (Rhea americana) (Struthioformes). Aspects of respiratory physiology and taxonomy].

The primary structures of the alpha A- und beta-chains from the major hemoglobin component of the Ostrich (Struthio camelus) and American Rhea (Rhea americana) are given. The minor component with the alpha D-chains was detected in Ostrich in several concentrations, in American Rhea as in chicken and pheasant (about 40%). By homologous comparison, Greylag Goose (Anser anser) hemoglobin and Ostrich alpha A-chains differ by 15 amino acids or 16 nucleotide (1 two-point mutation) exchanges, beta-chains by 4 exchanges. Four substitutions modify alpha 1 beta 1-contacts and one phosphate contact. American Rhea and Greylag Goose hemoglobin alpha A-chains differ by 20 amino acids or 23 nucleotides (3 two-point mutations), beta-chains by 4 exchanges. Two substitutions modify alpha 1 beta 1-contacts, one phosphate contact and one heme contact. Oxygen affinity of three hemoglobin components of Ostrich are measured and the results are discussed. Systematic and evolution of Ostrich and American Rhea are discussed.

Amino Acid Sequence↗
PubMed1982

The effect of experimental ligation of the external carotid artery and its major branches on haemorrhage from the maxillary artery.

The effect of ligation of the external carotid artery and its major branches on blood flow from the maxillary artery was investigated in four Chacma baboons. The left common carotid artery and its branches were surgically exposed and the maxillary artery was isolated, sectioned and cannulated. Blood flow from the proximal segment of the maxillary artery was determined with and without occlusion of the common carotid artery, the external carotid artery above and below the origin of the linguo-facial trunk and the posterior auricular occipital trunk. Ligation of the external carotid artery below and above the origin of the lingual and facial arteries reduced maxillary artery blood flow by 40% and 73% respectively. Ligation of the external carotid artery above the origin of the lingual and facial vessels, together with ligation of the posterior auricular occipital trunk reduced maxillary artery blood flow by 99.2%. On the basis of these experimental findings, it is suggested that maxillary artery haemorrhage in man may be most effectively controlled by ligation of the external carotid artery in the retromandibular fossa, distal to the origin of the posterior auricular artery, combined with ligation of the superficial temporal artery at the root of the zygoma.

Animals↗
PubMed1982

[The primary structure of the hemoglobin from a white rhinoceros (Ceratotherium simum, perissodactyla): beta 2 Glu].

The hemoglobin from a white rhinoceros (Ceratotherium simum) was analysed and the complete primary structure of the alpha and beta chains is described. The globin chains were separated on CM-cellulose column in 8M urea buffer. The amino acid sequences were mainly determined by automatic degradation of tryptic peptides in the sequenator. The results show, that globin consists of one alpha- and several beta-chain types. The beta chains differ at position beta 62 where the amino acids threonine, serine and alanine were identified and at position beta 116 where glutamine or lysine were found. The sequences are compared with those of horse, wild ass and zebra hemoglobin. Five amino acid residues of horse hemoglobin, which are involved in the alpha 1 beta 1 contacts are substituted in white rhinoceros hemoglobin. These substitutions are alpha 35 Gly leads to Ser, alpha 107 Ser leads to Val, alpha 111 Val leads to Leu, alpha 115 Asn leads to Gln and beta 116 Arg leads to Gln or Lys. Furthermore glutamic acid was found at position beta 2 of rhinoceros hemoglobin. In most mammalian hemoglobins the amino acid at this position is histidin which is one of the residues that binds, 2,3-bisphosphoglycerat in deoxyhemoglobin. In this way 2,3-bisphosphoglycerat controls the oxygen affinity of hemoglobin.

Amino Acid Sequence↗
PubMed1981

Intussesception after jejunoileal bypass as diagnosed by ultrasound.

Eighty patients who had undergone jejunoileal bypass for morbid obesity were examined by ultrasound at their routine follow-up visits to the clinic. Ultrasonographic evidence of intestinal intussusception was found in 15 patients (19%). Two of these patients were asymptomatic. Ultrasonographic findings were confirmed by operation in 6 patients (5 with intussusception, 1 negative).

Adult↗
PubMed1981

Abdominal ultrasound in patients with acute right upper quadrant pain.

Ultrasonography was performed as the first imaging procedure in 100 patients who presented with acute right upper quadrant pain suggestive of cholecystitis or cholelithiasis. In the final analysis 46 patients were found to have gallbladder disease (40 patients with cholelithiasis, 5 with acalculous cholecystitis, and 1 with a cholesterol polyp in the gallbladder). In 22 of 54 patients with a normal gallbladder, other abdominal disease was found. The error rate for ultrasound was 5%, and in 4 patients ultrasound was not the suitable procedure for the diagnosis. In 91 patients the ultrasonographic diagnosis was correct.

Acute Disease↗