Biomedical subjects
C J Mitchell
Publications and source records attributed to C J Mitchell.
The use of sodium fluoride, vitamin D and calcium supplements in the treatment of patients with axial osteoporosis.
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The diagnosis of the site of upper gastrointestinal haemorrhage in patients with established portal hypertension.
Seventy-five endoscopies were performed in 60 patients known to have oesophageal varices presenting with further upper gastrointestinal haemorrhage during the previous 72 hours. A site of active bleeding was found at 50 of 75 examinations (67 percent) including all 21 patients endoscoped within three hours of the last haemorrhage. Variceal bleeding alone was seen in 40 of these 50 examinations (80%) and both varices and mucosal lesions were bleeding in 4 patients; mucosal lesions were an uncommon cause of haemorrhage and only 6 patients were bleeding from these alone. The adult GIF-D2 endoscope was used for 45 examinations. Variceal bleeding was restarted on three occasions and prolonged unconsciousness induced by intravenous diazepam in one patient. In contrast, the paediatric GIF-P endoscope (30 examinations) was easily tolerated with little or no sedation, did not impair diagnostic accuracy and was not associated with any complications.
Renal handling of gentamicin and other antibiotics by the isolated perfused rat kidney: mechanism of nephrotoxicity.
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Automated reagin test using a particular counter.
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Rational sequence of tests for pancreatic function.
Of 144 patients with suspected pancreatic disease in whom a 75Se-selenomethionine scan was performed, endoscopic retrograde pancreatography (ERP) was successful in 108 (75%). The final diagnosis is known in 100 patients and has been compared with scan and ERP findings. A normal scan reliably indicated a normal pancreas, but the scan was falsely abnormal in 30%. ERP distinguished between carcinoma and chronic pancreatitis in 84% of cases but was falsely normal in five patients with pancreatic disease. In extrahepatic biliary disease both tests tended to give falsely abnormal results. A sequence of tests to provide a rapid and reliable assessment of pancreatic function should be a radio-isotope scan, followed by ERP if the results of the scan are abnormal, and a Lundh test if the scan is abnormal but the findings on ERP are normal.
An automated test for the detection of significant bacteriuria.
A fully automated technique for the rapid detection of significant bacteriuria is described. The method, which depends on the detection of bacterial adenosine triphosphate (A.T.P.) by bioluminescence, was found to have better sensitivity than a conventional cultural technique which uses a standardised loop. Results were available in 30 minutes. In the 957 urine samples tested, specificity was 84.5% relative to a pour-plate technique; results were not affected by the presence of non-bacterial elements.
Pancreatic scanning.
The 75Se-selenomethionine pancreas scan cannot differentiate between chronic pancreatitis and carcinoma of the pancreas and may--although chiefly in certain defined clinical conditions--give a false-positive result. It is also rather more time-consuming than other radioisotopic scanning procedures. Its value in clinical practice stems from the fact that all the other methods currently available for studying the pancreas have their own disadvantages. Because a normal scan is only rarely seen in patients with carcinoma of the pancreas, pancreatic scanning can be particularly useful in helping to decide which patients should, and which should not, be subjected to other procedures involving greater discomfort or risk.
Experimental transmission of Japanese encephalitis virus by Culex tritaeniorhynchus and C. fuscocephalus.
Experimental transmission of Japanese encephalitis virus from swine to baby chicks was accomplished using Culex tritaeniorhynchus and Culex fuscocephalus, two of three mosquito species in Taiwan from which the virus has been recovered in nature. Whereas neither species had become infective by the twelfth day, one of ten C. fuscocephalus and 11 of 51 C. tritaeniorhynchus were infective by the seventeenth day of extrinsic incubation as verified by viraemia in chicks fed upon by potentially infective mosquitoes. The highest transmission rate obtained was 81% for C. tritaeniorhynchus on the twenty-first day of extrinsic incubation.
Letter: Acute brucellosis presenting as epididymo-orchitis.
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Preliminary studies on the control of Japanese encephalitis vectors in Taiwan by chemical means.
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Susceptibility and resistance of four Culex species in Taiwan to certain insecticides.
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Exploratory trials utilizing a mermithid nematode as a control agent for Culex mosquitos in Taiwan.
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House sparrows, Passer domesticus (L.), as hosts of arboviruses in Hale County, Texas. I. Field studies, 1965-1969.
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House sparrows, Passer domesticus (L.), as hosts of arboviruses in Hale County, Texas. II. Laboratory studies with Western equine encephalitis virus.
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Ecological studies on the mosquito vectors of Japanese encephalitis.
These studies were conducted in China (Province of Taiwan) to assess the populations of known and potential mosquito vectors of Japanese encephalitis in a typical endemic area, and to evaluate a variety of sampling techniques, some of which were new. Culex annulus was found to be the predominant vector species in the study area during the epidemic season; C. tritaeniorhynchus was never abundant, and C. fuscocephalus was rare. C. annulus and C. tritaeniorhynchus were active throughout the year, although populations were at a low level during the cool season. The results show that attention must be given to C. annulus as a possible vector where it is present in JE foci. The collection of mosquitos during the early evening hours from buffalo bait tethered outdoors was found to be the most efficient and sensitive means of monitoring vector populations throughout the year. During the JE epidemic season remarkable results were obtained with a vacuum sweep-net.
Host-feeding patterns and behaviour of 4 Culex species in an endemic area of Japanese encephalitis.
Studies were made on the host-feeding patterns and behaviour of 4 Culex species in China (Province of Taiwan) to further assess their importance as vectors of Japanese encephalitis. A relatively unbiased, non-attractant technique (vacuum sweep-net) was used for collecting mosquitos resting outdoors on rural premises; blood meals from engorged specimens were identified by precipitin tests. Additional information was obtained by analysing data from related studies. Precipitin-test results indicated that C. annulus, C. tritaeniorhynchus, and C. fuscocephalus feed principally on mammals, the first species mainly on swine and the latter two largely on bovine hosts. Mosquito forage ratios suggested that the apparent preference of C. annulus for swine over bovine hosts might be a function of host density. C. annulus was found to be zoophilic, exophilic, and exophagic; however, in view of its abundance during the JE epidemic season, contact with human hosts may reach a significant level, even indoors. The other 3 species of Culex were considered to be of lesser importance as JE vectors during the 1971 epidemic season because of their host-feeding patterns and/or population densities.
Seasonal infection of Culex mosquitos and swine with Japanese encephalitis virus.
A year-round study of the infection rates of JE virus in Culex mosquitos was made during 1970-71 in 2 hamlets in Taoyuan County, China (Province of Taiwan). JE virus was recovered from 5 of 314 pools of C. annulus, and from 1 of 22 pools of C. tritaeniorhynchus; these recoveries occurred during a 14-day period in July 1971. None of the 288 pools of C. p. fatigans, which had been collected between October and April, was positive. In addition, sentinel swine were assessed for antibody and virus. All the pigs became highly immune by 23 July; in each hamlet all the pigs had become infected within 1 week, virus being detected in them for only 1-2 weeks. Virus-positive mosquitos appeared to have obtained their infections at about the time that viraemia was occurring in the sentinel swine. These observations illustrate once again the lower infection rate and shorter duration of virus-positive mosquitos in China (Province of Taiwan) as compared with Japan.