St Thomas' Hospital

About: St Thomas' Hospital is a healthcare organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Pregnancy. The organization has 12105 authors who have published 15596 publications receiving 624309 citations. The organization is also known as: St Thomas's Hospital & St. Thomas's.

Patch testing with a new fragrance mix detects additional patients sensitive to perfumes and missed by the current fragrance mix.

Abstract: The currently used 8% fragrance mix (FM I) does not identify all patients with a positive history of adverse reactions to fragrances. A new FM II with 6 frequently used chemicals was evaluated in 1701 consecutive patients patch tested in 6 dermatological centres in Europe. FM II was tested in 3 concentrations - 28% FM II contained 5% hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral), 2% citral, 5% farnesol, 5% coumarin, 1% citronellol and 10%alpha-hexyl-cinnamic aldehyde; in 14% FM II, the single constituents' concentration was lowered to 50% and in 2.8% FM II to 10%. Each patient was classified regarding a history of adverse reactions to fragrances: certain, probable, questionable, none. Positive reactions to FM I occurred in 6.5% of the patients. Positive reactions to FM II were dose-dependent and increased from 1.3% (2.8% FM II), through 2.9% (14% FM II) to 4.1% (28% FM II). Reactions classified as doubtful or irritant varied considerably between the 6 centres, with a mean value of 7.2% for FM I and means ranging from 1.8% to 10.6% for FM II. 8.7% of the tested patients had a certain fragrance history. Of these, 25.2% were positive to FM I; reactivity to FM II was again dose-dependent and ranged from 8.1% to 17.6% in this subgroup. Comparing 2 groups of history - certain and none - values for sensitivity and specificity were calculated: sensitivity: FM I, 25.2%; 2.8% FM II, 8.1%; 14% FM II, 13.5%; 28% FM II, 17.6%; specificity: FM I, 96.5%; 2.8% FM II, 99.5%; 14% FM II, 98.8%; 28% FM II, 98.1%. 31/70 patients (44.3%) positive to 28% FM II were negative to FM I, with 14% FM II this proportion being 16/50 (32%). In the group of patients with a certain history, a total of 7 patients were found reacting to FM II only. Conversely, in the group of patients without any fragrance history, there were significantly more positive reactions to FM I than to any concentration of FM II. In conclusion, the new FM II detects additional patients sensitive to fragrances missed by FM I; the number of false-positive reactions is lower with FM II than with FM I. Considering sensitivity, specificity and the frequency of doubtful reactions, the medium concentration, 14% FM II, seems to be the most appropriate diagnostic screening tool.

Characterization of the “border zone” in acute regional ischemia in the dog

Abstract: A biopsy instrument with multiple drill heads was used to retrieve simultaneously, and freeze within seconds, 29 individual transmural tissue samples from the left ventricular wall of the dog heart. Studies were undertaken 21 to 26 minutes after coronary arterial ligation to define the border zone between ischemic and nonischemic tissue using the following criteria: (1) metabolic changes (adenosine triphosphate, creatine phosphate, glycogen, lactate, potassium, sodium, water); (2) electro-cardiographic S-T changes; and (3) blood flow distribution (microspheres). The existence, position and sharpness of the gradients for each variable were defined in relation to the edge of the visible area of cyanosis. Adenosine triphosphate, creatine phosphate and lactate values in the nonischemic tissue were essentially constant until 2 to 3 mm from the edge of visible cyanosis. The high energy phosphate content of the tissue then decreased sharply across a zone 8 to 15 mm wide that spanned the visible edge. Across this zone lactate content increased sharply as did S-T segment elevation, and coronary flow decreased to approximately 20 percent of the control value. Multiple cross-correlation studies revealed that changes in the tissue content of adenosine triphosphate, creatine phosphate and lactate were accurately reflected by S-T segment changes, and further that all of these variables were directly related to the degree of ischemia, as indicated by the reduction in coronary flow. In addition to confirming the existence of a clearly defined border zone, these studies suggest that therapeutic salvage of this zone could considerably influence the extent of the ultimate infarct.