Sensation taste

Several aspects affect the extent and character of taste and smell. People differ considerably in sensitivity and appreciation of smell and taste, and there is lack of a common language to describe smell and taste experiences. A hereditary or genetic factor may cause a variation between individual reactions, eg, phenylthiourea causes a bitter taste sensation which may not be perceptible to certain people whose general abiUty to distinguish other tastes is not noticeably impaired (17). The variation of pH in saUva, which acts as a buffer and the charge carrier for the depolarization of the taste cell, may influence the perception of acidity differently in people (15,18). Enzymes in saUva can cause rapid chemical changes in basic food ingredients, such as proteins and carbohydrates, with variable effects on the individual. 

Cloying A taste sensation that stimulates beyond the point of satiation frequently used to describe overly sweet products. 

Penicillamine (29) can be effective in patients with refractory RA and may delay progression of erosions, but adverse effects limit its useflilness. The most common adverse side effects for penicillamine are similar to those of parenteral gold therapy, ie, pmritic rash, protein uria, leukopenia, and thrombocytopenia. Decreased or altered taste sensation is a relatively common adverse effect for penicillamine. A monthly blood count, platelet count, and urinalysis are recommended, and also hepatic and renal function should be periodically monitored. Penicillamine is teratogenic and should not be used during pregnancy. 

Detection. Many people can detect hydrogen cyanide by odor or taste sensation at the 1 ppm concentration in air, most at 5 ppm, but HCN does not have an offensive odor and a few people cannot smell it even at toxic levels. Anyone planning to work with hydrogen cyanide should be checked with a sniff test employing a known safe concentration. This test should be given periodically. Several chemical detection and warning methods can be employed. The most rehable are modem, electronic monitors based on electrolytes that react with hydrogen cyanide. 

As early as 1848, it had been suggested that sensory receptors transduce only one sensation, independent of the manner of stimulation. Behavioral experiments tend to support this theory. In 1919, Renqvist proposed that the initial reaction of taste stimulation takes place on the surface of the taste-cell membrane. The taste surfaces were regarded as colloidal dispersions in which the protoplasmic, sensory particles and their components were suspended in the liquor or solution to be tested. The taste sensation would then be due to adsorption of the substances in the solution, and equal degrees of sensation would correspond to adsorption of equal amounts. Therefore, the rate of adsorption of taste stimulants would be proportional to the total substances adsorbed. The phenomenon of taste differences between isomers was partly explained by the assumption that the mechanism of taste involves a three-dimensional arrangement for example, a layer of fatty acid floating on water would have its carboxylic groups anchored in the water whereas the long, hydrocarbon ends would project upwards. 

A century ago, Fick proposed the concept of four primary tastes, namely, sweet, salty, sour, and bitter. It has since been found that taste sensations are not describable by a single collection of discrete primaries. Electrophysiological studies of afierent taste-units in the chorda tympani and glossophyrangeal nerves have revealed that a continuous spectrum of gustation may be based on these four taste elements. Furthermore, the intensities of the tastes that we commonly experience are due not only to gustatory sensations but also to tactile, hot and cold, and, above all, olfactory sensations. The complexities of taste studies are such that, unless one of the taste modalities is singled out for study, there is very little hope of success. 

Tea provides a broad spectrum of flavor experience there is a considerable degree of diversity in the flavor of different varieties green tea and oolong tea provided very different taste sensations from those of black tea flavorants and other additives allow for still greater variety tea is appreciated both as a hot and a cold beverage. 

The answer is b. (1 Iardman, pp 750-751) Angiotensin converting enzyme inhibitors, especially captopril, can cause alteration or loss of taste sensation... 

Protein-energy malnutrition is common in patients with stage 4 or 5 CKD. Food intake is often inadequate because of anorexia, altered taste sensation, intercurrent illness, and unpalatability of prescribed diets. 

It is noted that, as is shown in Figure 15, the chemicals with different taste-responses show markedly different effects on the dynamic behavior of the phospholipid film. Detail discussion on the chemical response in relation to the mechanism of taste sensation has already been given in a series of studies from our research group [3,42,43]. 

In humans, sensors for taste are collected in structures known as taste buds. Your mouth contains about 10,000 taste buds the majority are located at various sites on your tongue. The remainder are found in the pharynx, epiglottis, and at the entrance to the esophagus. Each taste bud senses and reacts to all five primary taste sensations. I want to dispel an old, untrue but widely held belief that different parts of the tongue are devoted to different tastes. It just isn t so, regardless of what you might have been taught or otherwise have been led to believe. 

There are five primary taste sensations salty, sour, sweet, bitter, and umami (or savory). The receptors for these tastes are encoded in a few dozen genes in the human genome. These are expressed in taste buds. 

Researchers have oscillated between emphasizing specificity of neurons ( labeled lines ) and responses to a spectrum of tastants by one cell. More recently, patterns of activation of a number of sensory cells are favored for coding specific taste sensations (Smith and Margolskee, 2001). Neural distinction of different tastes requires simultaneous activation of different cell types. The brain receives a single channel of information, simply bitter for a number of different compounds. 

Severe headaches occurred in an individual exposed to diesel fuel vapor for 10 days (Reidenberg et al. 1964). Anorexia occurred in a man following dermal and/or inhalation exposure to diesel fuel over several weeks (Crisp et al. 1979). Other neurological effects were reported following inhalation of JP-5 vapor in two individuals who had fatigue and coordination and concentration difficulties other effects included headache, apparent intoxication, and anorexia. Effects subsided within 24 hours for one individual and within 4 days for the other (Porter 1990). Sensory impairment did not occur in these individuals. However, experimental data indicate that olfactory fatigue and taste sensation may occur in some individuals after a 15-minute inhalation exposure to 140 mg/m deodorized kerosene vapor (Carpenter et al. 1976). These data suggest that the different types of fuel oils may behave differently under inhalation exposure conditions. The effect of deodorized kerosene may also occur at lower doses, but this cannot be determined from these data. 

Undesired effects. The magnitude of the antihypertensive effect of ACE inhibitors depends on the functional state of the RAA system. When the latter has been activated by loss of electrolytes and water (resulting from treatment with diuretic drugs), cardiac failure, or renal arterial stenosis, administration of ACE inhibitors may initially cause an excessive fall in blood pressure. In renal arterial stenosis, the RAA system may be needed for maintaining renal function and ACE inhibitors may precipitate renal failure. Dry cough is a fairly frequent side effect, possibly caused by reduced inactivation of kinins in the bronchial mucosa. Rarely, disturbances of taste sensation, exanthema, neutropenia, proteinuria, and angioneurotic edema may occur. In most cases, ACE inhibitors are well tolerated and effective. Newer analogues include lisinopril, perindo-pril, ramipril, quinapril, fosinopril, benazepril, cilazapril, and trandolapril. 

Abdominal cramps, vomiting, and diarrhea occurred in a truck driver who was exposed to diesel fuel vapor for 10 days while driving a truck with a leaking fuel injector. Acute renal failure was also observed. One case study describes eye irritation in two individuals exposed to JP-5 fuel (kerosene) for approximately 1 hour while flying an airplane. Coordination and concentration difficulties were noted, as were headache, apparent intoxication, and anorexia. Inhalation of 140mg/m deodorized kerosene by six volunteers caused olfactory fatigue in three subjects and a taste sensation in... 

Ice cream emulsion has a very characteristic degree of stability. The air bubbles should remain dispersed, but as soon it melts in the mouth, the emulsion should break. This leads to the sensation of taste, which is very essential to enjoy its specialness. The sensation of taste on the surface of the tongue is known to be related to molecular shape and physicochemical properties. As soon as these molecules are separated from the emulsion, the taste sensation is recorded in the brain. Therefore, the various components must stay in the same phase after the breakup of the emulsion. Emulsifiers that are generally used have low HLB values (for W/O), and have been found to have considerable effect on the structure of the ice cream. 

Penicillamine is readily absorbed from the GI tract and is rapidly excreted in the urine, largely as the intact molecule. Gradually increasing its dose minimizes side effects, which necessitate discontinuance of penicillamine therapy in perhaps one-third of patients. The most common side effects are maculopapular pruritic dermatitis, GI upset, loss of taste sensation, mild to occasionally severe thrombocytopenia and leukopenia. 

Peridex Disrupts cell membranes Altered taste sensation O O... 

Early signs of overdosage are manifested as weakness, headache, somnolence, nausea, vomiting, dry mouth, constipation, muscle and bone pain, and metallic taste sensation. 

Ophthalmic Bad taste, sensation of something in eye, eyelid redness or itching... 

Altered taste sensation, dizziness, somnolence, weight gain, constipation, diarrhea, heartburn, nausea, vomiting, stomach fullness, headache... 

Abnormal taste sensation, heartburn, symptomaticurinary tract disease, transient renal dysfunction... 

Evaluate food tolerance and change in taste sensation... 

GI disturbances (nausea, GI distress, metallic taste sensation), photosensitivity Rare... 

Altered taste sensation, constipation, vomiting, stomach fullness Serious Reactions... 

Gastrointestinal (Gl) disturbances, such as nausea, and a metallic taste sensation. Rare... 

In a further study, Dias et al. (2009) studied the deployment of a potentiometric electronic tongue based on an array of 36 sensors, for the recognition of the basic taste sensations and for the detection of fraudulent additions of bovine milk to ovine milk. The signals were processed by means of PCA and LDA (see Fig. 2.26), and the classification rules were evaluated by means of cross-validation. The results presented are excellent for fitting but not very satisfactory for prediction. 

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