| thioclastic cleavage | The splitting of a bond in fashion analogous to hydrolysis or phosphorolysis except that the elements of a substituted hydrogen sulfide (usually coenzyme A) are added across the break. (05 Mar 2000) |
|---|---|
| enamel cleavage | The splitting of enamel in a plane parallel to the direction of the enamel rods. (05 Mar 2000) |
| equal cleavage | Cleavage producing blastomeres of like size. (05 Mar 2000) |
| equatorial cleavage | Cleavage in which the plane of cytoplasmic division is at right angles to the axis of the ovum. (05 Mar 2000) |
| yolk cleavage | Segmentation of the vitellus. (05 Mar 2000) |
| unequal cleavage | Cleavage producing blastomeres of different sizes at the two poles. (05 Mar 2000) |
| freeze cleavage | Method of specimen preparation for the electron microscope in which rapidly frozen tissue is cracked so as to produce a fracture plane through the specimen. The surface of the fracture plane is then shadowed by heavy metal vapour, strengthened by a carbon film and the underlying specimen is digested away, leaving a replica that can be picked up on a grid and examined in the transmission electron microscope. The great advantage of the method is that the fracture plane tends to pass along the centre of lipid bilayers and it is therefore possible to get en face views of membranes that reveal the pattern of Integral membrane proteins. The E face is the outer lamella of the plasma membrane viewed as if from within the cell, the P face the inner lamella viewed from outside the cell. Fracture planes also often pass along lines of weakness such as the interface between cytoplasm and membrane, so that outer and inner membrane surfaces can be viewed. Further information about the structure can be revealed by freeze etching. Extremely rapid freezing followed by deep etching has allowed the structure of the cytoplasm to be studied without the artefacts that might be introduced by fixation. (18 Nov 1997) |
| radical mastectomy, total | Breast cancer treatment involving removal of the breast, the pectoral (chest) muscles, lymph nodes (the glands ) in the armpit and associated skin and subcutaneous tissue. (12 Dec 1998) |
| parenteral nutrition, home total | The at-home administering of nutrients for assimilation and utilization by a patient whose sole source of nutrients is via solutions administered intravenously, subcutaneously or by some other non-alimentary route. (12 Dec 1998) |
| parenteral nutrition, total | The delivery of nutrients for assimilation and utilization by a patient whose sole source of nutrients is via solutions administered intravenously, subcutaneously, or by some other non-alimentary route. The basic components of tpn solutions are protein hydrolysates or free amino acid mixtures, monosaccharides, and electrolytes. Components are selected for their ability to reverse catabolism, promote anabolism, and build structural proteins. (12 Dec 1998) |
| reversal of organs, total | This condition (medically called situs inversus totalis) involves complete transposition (right to left reversal) of the thoracic and abdominal organs. The heart is not in its usual position in the left chest but is on the right. Specifically related to the heart, this is referred to as dextrocardia (literally, right-hearted). And the stomach, which is normally in the left upper abdomen, is on the right. In patients with situs inversus totalis, all of the chest and abdominal organs are reversed and appear in mirror image when examined or visualised by tests such as X-ray filming. Situs inversus totalis has been estimated to occur once in about 6-8,000 births. Situs inversus occurs in a rare abnormal condition that is present at birth (congenital) called kartagener's syndrome. (12 Dec 1998) |
| communication methods, total | Utilization of all available receptive and expressive modes for the purpose of achieving communication with the hearing impaired, such as gestures, postures, facial expression, types of voice, formal speech and non-speech systems, and simultaneous communication. (12 Dec 1998) |
| congenital total lipodystrophy | Lipodystrophy characterised by almost complete lack of subcutaneous fat, accelerated rate of growth and skeletal development during the first 3 to 4 years of life, muscular hypertrophy, cardiac enlargement, hepatosplenomegaly, hypertrichosis, renal enlargement, hypertriglyceridemia, and hypermetabolism; both autosomal dominant and X-linked varieties exist. (05 Mar 2000) |
| hysterectomy, total | Complete surgical removal of the uterus and cervix. Also called a complete hysterectomy. (12 Dec 1998) |
| near-total thyroidectomy | Removal of nearly all of each thyroid lobe leaving unresected only a small portion of gland adjacent to the entrance of the recurrent laryngeal nerve into the larynx. (05 Mar 2000) |