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Biomedical subjects

D Hirst

Publications and source records attributed to D Hirst.

27 records · Page 2Linked to original sources
PubMed1990

Somatosensory and auditory brain stem conduction after head injury: a comparison with clinical features in prediction of outcome.

Evoked potential conduction times in brain stem auditory (BCT) and central somatosensory pathways (CCT) were recorded from 23 normal subjects and 101 patients with severe head injury. Abnormalities in the CCT and the BCT findings correlated with the clinical indices of brain damage (coma score, motor response, pupil response, and spontaneous and reflex eye movements) in the head-injured patients and each correlated with outcome at 6 months from the injury. The CCT in the "best" hemisphere produced the strongest correlation with outcome (P less than 0.001). The correlation of the CCT with outcome was stronger in the 47 patients examined 2 to 3 days after the injury (P less than 0.001) compared to the 34 patients examined within 24 hours after the injury (P less than 0.02). No such difference was noted for the BCT. Serial studies within the first 2 weeks of injury did not show a consistent pattern and repetition of the investigation over this period did not provide any additional information. We used an INDEP-SELECT discriminant analysis program to determine whether information from the evoked potential data could improve prediction of outcome based on clinical data alone. With the addition of the CCT, the predictive accuracy (expressed as the correct classification probability) increased only slightly from 77 to 80%, and the difference was not significant. We conclude that central somatosensory and auditory brain stem conduction times provide useful prognostic information in paralyzed or sedated patients, but when neurological examination is feasible the benefits of evoked potential analysis do not justify the effort involved in data collection.

Acoustic Stimulation↗
PubMed1989

36 cases of bites by spiders, including the white-tailed spider, Lampona cylindrata.

Thirty-six cases of bites by spiders are reported; in all cases, the spider was identified. No cases resulted in the formation of local ulcers, in necrosis, or in serious systemic symptoms. Eight bites by Lampona cylindrata, the white-tailed spider, caused a mild sting to sharp pain of short duration, itchiness, erythema, local swelling or a lump, and either no systemic symptoms, or anxiety. Five bites by Badumna insignis, the black house-spider, caused local pain, erythema, swelling, and no systemic symptoms, or anxiety, or chest pain and shortness of breath of mild degree and of short duration. The other spiders to be reported as causing bites were Hadronyche adelaidensis, Misgolas andrewsi, Aganippe subtristis, Olios calligaster, Isopeda pessleri, Eriophora sp., Phonognatha graeffei, Holoplatys sp., Breda jovialis, Opisthoncus sp., Lycosa sp. and Achaearanea tepidariorum.

Adolescent↗
PubMed1988

Detection of acute radiation damage to the spleen in mice by using fluorine-19 MR imaging.

Previous work in our laboratory has shown that an IV-administered emulsion of perfluorooctylbromide, an agent known to localize in functioning macrophages in the reticuloendothelial system, can be detected in the liver and spleen by using fluorine-19 (19F) MR imaging. In mice that have received a single radiation dose of 1300 rad (13 Gy) (250 kVp) to the abdomen, relatively diminished uptake of perfluorooctylbromide emulsion in the spleen is seen as few as 12 days after irradiation when using 19F MR. When a GE NMR CSI 2-T spectroscopy/imaging system was used, 19F MR images were obtained in 2-16 min, and the postirradiation changes in the spleen were shown. This approach is the first that allows detection of acute postirradiation damage in the spleen in as few as 12 days and potentially allows assessment of macrophage dysfunction in vivo.

Acute Disease↗
PubMed1987

Craniofacial characteristics of subjects with normal and postnormal occlusions--a longitudinal study.

Lateral skull radiographs of 85 growth study children taken at 5, 10, and 15 years of age, with normal/Class I occlusion (normal) and Class II, Division 1/Division 2 occlusion (postnormal) were digitized and analyzed by means of stepwise discriminant analysis. The cranial base angle proved to be the best discriminator between the two groups, the value at age 5 years being an accurate predictor of the occlusal type at 15 years in 73% of subjects. Although the majority of subjects grew predictably, their craniofacial characteristics being compatible with their ultimate occlusal type, 17% showed a growth trend from postnormal to normal and 9% a trend from normal to postnormal. By 15 years of age, only 8% of subjects possessed an occlusion at variance with their facial type. The cranial base angle is suggested as the fundamental determinant of jaw relation, but in some subjects this may be compensated by differential jaw growth manifested by a change in angle ANB.

Adolescent↗
PubMed1980

Vitamin D prophylaxis and osteomalacia in chronic cholestatic liver disease.

Bone histology was examined in 32 patients with chronic cholestatic liver disease, of whom just over one half were receiving high-dose parenteral vitamin D therapy. Four patients had histological evidence of osteomalacia; two of these were receiving vitamin D therapy, and showed only very mild osteomalacia, while the remaining two untreated patients had more severe bone disease. Plasma 25-hydroxyvitamin D levels were normal in all vitamin D-treated patients, and serum calcium concentrations were significantly higher in the treated group. Clinical symptoms and biochemical and radiological findings were unreliable in predicting osteomalacia. It is concluded that osteomalacia is uncommon in patients with chronic cholestatic liver disease irrespective of whether or not they are receiving vitamin D therapy. However, high-dose parenteral vitamin D prophylaxis protects against vitamin D deficiency and may also prevent the development of severe bone disease.

Adult↗
PubMed1978

Spectrum of renal tubular damage in renal failure secondary to cirrhosis and fulminant hepatic failure.

Measurements of urinary lysozyme were used to evaluate renal tubular integrity in 34 patients with cirrhosis or fulminant hepatic failure who had developed renal impairment. In 18 of the patients the lysozyme values were normal but in the remaining 16 were increased, supporting previous concepts that renal failure complicating hepatocellular disease may occur both without and with tubular necrosis. The lysozyme values were inversely related to the creatinine clearance, suggesting that the development of tubular necrosis may be determined by the level of renal perfusion. The validity of simpler laboratory tests often used to assess renal tubular integrity--namely, the urine sodium concentration, the urine:plasma osmolality ratio, and casts in the urine sediment--was evaluated by comparison with the lysozyme measurements. The urine sodium concentration was of most value and the findings in the sediment were of no value at all.

Acute Kidney Injury↗
PubMed1977

The distribution and significance of hepatitis B surface antigen in a rural population in Kenya.

A rural population in Kenya was studied and a prevalence of HBsAg of 5-0% and an antibody prevalence of 50% in HBsAg in negative subjects has been found; 1-2% of the negative subjects converted to positive over a six-month period. A group of HBsAg positive subjects was compared with a matched group of HBsAg negative controls clinically in liver function tests and past medical history. No statistically significant differences were found between the two groups and neither group had experienced in the past significantly more skin scarification, injections or illness with jaundice. Both ad and ay subtypes occurred in the population. This is an unexpected and important finding, which gives scope for further detailed epidemiological studies in this population.

Adolescent↗
PubMedDate not supplied

Abdominal aortic aneurysm and stent graft phantom manufactured by medical rapid prototyping.

A novel human aorta phantom built by medical rapid prototypingfor use in computed tomography (CT) scanning is described. The phantom contained a stent graft that was deployed internally to mimic a repaired aortic aneurysm. The phantom was produced to allow assessment of the CT appearance of a stent graft inside an aorta using the new virtual intravascular endoscopy image presentation technique. The stent graft utilized contained suprarenal components (metalfixation struts), and these were placed with these struts covering the renal artery ostia. The phantom was filled with iodinated contrast medium at a concentration that produced a density similar to that found in normal CT angiographic scanning. The model was scanned at a variety of slice thicknesses, pitch and image reconstruction intervals. Visualization of the stent suprarenal components in relation to the renal artery ostia is shown and the overestimation of stent wire strut diameter demonstrated.

Aortic Aneurysm, Abdominal↗