Creaming in black tea

Tea cream is the precipitate formed as tea cools. Its formation has been studied by X-ray scattering, and it is shown that a higher tea concentration leads to earlier onset of creaming and larger particles and that addition of theaflavin and calcium promotes creaming. Association constants between the major components of black tea have been obtained using NMR and show that calcium and glucose enhance the self-association of caffeine, polyphenols, and theaflavin but have little effect on hetero-association. Glycosylation of a polyphenol reduced self-association and reduced binding to caffeine. We conclude that theaflavin is important for the initiation of creaming, forming nanoclusters of typically 3 nm diameter, whereas caffeine acts more to fill in the gaps within the clusters and thus adds to the bulk of tea cream without being necessary for its initiation. Tea creaming may be reduced by increasing the solubility of the polyphenols (i.e., by glycosylation) or by removing calcium. Tea cream; theaflavin; caffeine; small-angle X-ray scattering; NMR; colloid.     

A COMPARISON OF MANUAL AND AUTOMATIC ULTRASOUND-GUIDED BIOPSY TECHNIQUES

A manual, ultrasound-guided biopsy technique was compared to a new automatic method using a new biopsy device. The liver and the left kidney of 10 dogs were biopsied using the two methods. The specimens from the biopsies were compared for size and quality. Results demonstrate that larger and higher quality samples were obtained with the new automatic method.     

Development of an opiate-based anaesthetic technique for use in dogs with cardiomyopathy.

An opiate-based anaesthetic technique has been developed for use in dogs with end-stage heart failure due to dilated cardiomyopathy. It has been used in dogs undergoing translocation of the left latissimus dorsi around the descending thoracic aorta to create an autologous counterpulsation system. Anaesthesia was induced with barbiturate (10 mg/kg thiopentone) and fentanyl (500 micrograms) and maintained by an infusion of fentanyl (0.5 micrograms/kg/minute) [corrected] in addition to halothane (0.1 to 0.5 per cent) and nitrous oxide (20 to 60 per cent). This technique provided safe anaesthesia for major intrathoracic surgery.     

An investigation into alternative methods for the serodiagnosis of dourine

The complement fixation test (CFT), indirect fluorescent antibody test (IFAT), card agglutination test for trypanosomiasis (CATT) and enzyme-linked immunosorbent assay (ELISA) were compared in their application to the serological diagnosis of Trypanosoma equiperdum infection in 43 horses. The CFT remains a reliable test for dourine, especially in countries where other members of the subgenus Trypanozoon do not occur. The IFAT is a good 'back-up' test, but, requiring skilled operators it has the disadvantage of making it labour intensive, and interpretation of results subjective. This makes it more suited to small numbers of samples. The ELISA is suitable for large numbers of samples and could readily be used in routine diagnostic procedures. The CATT could be of value in field situations, although it does not appear to be as sensitive as the CFT. Its possible application under these conditions should be further investigated.     

EFFECT OF DEPENDENCY VERSUS NONDEPENDENCY ON LUNG LESION VISUALIZATION

Paraffin blocks and mineral oil were used as a model to determine the effect of dependency versus nondependency on radiographic visualization of lung lesions in lateral thoracic radiographs. It was concluded that the increased opacity of the material surrounding the lesion, not contact between the heart and the lesion, was responsible for the inability to detect lung disease in the dependent lung. The results were tested in dogs with pneumonia in the right middle lung lobe. When the dog was in right lateral recumbency, the dependent right lung was increased in opacity and decreased in volume and the pulmonary lesion was difficult to detect. When the dog was in left lateral recumbency, the nondependent right lung was increased in volume and decreased in opacity and the pulmonary disease was clearly visible. A single recumbent lateral radiograph must not be used to assess a dog with suspected lung disease because lesions in the dependent lung lobes may not be detected.