Sunday, December 6, 2009
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prothrombin (Encyclopædia Britannica) glycoprotein (carbohydrate-protein compound) occurring in blood plasma and an essential component of the blood-clotting mechanism. Prothrombin is transformed into thrombin by a clotting factor known as factor X or prothrombinase; thrombin then acts to transform fibrinogen, also present in plasma, ...
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prothrombin (Encyclopædia Britannica) glycoprotein (carbohydrate-protein compound) occurring in blood plasma and an essential component of the blood-clotting mechanism. Prothrombin is transformed into thrombin by a clotting factor known as factor X or prothrombinase; thrombin then acts to transform fibrinogen, also present in plasma, ...
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prothrombin. [Art]. Retrieved December 6, 2009, from Encyclopædia Britannica Online: http://search.eb.com/eb/art-45588
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Link your Web site or blog to this Britannica Online article. Please note that access to Britannica Online is necessary for others to view the article. Use the code provided below to create a link. You can also share this Britannica article with people who do not have access to Britannica Online, though advertising and promotions may appear. Use the code provided below to create a public link for your Web site or blog.prothrombin
Antithrombin
also called antithrombin III or ATIII an anticlotting substance occurring in the plasma of blood that functions primarily to block the action of thrombin, an enzyme central to coagulation—the process by which a clot is formed. AT combines with thrombin as well as most of the other activated blood-clotting proteins (e.g., factors Xa and IXa) to form inert complexes. This action is greatly enhanced by the presence of heparin, a substance formed by mast cells of the connective tissue.
Hereditary AT deficiency is associated with an excessive tendency toward clot formation, and manifestations of this defect are recurrent thrombophlebitis and pulmonary embolism
Hereditary AT deficiency is associated with an excessive tendency toward clot formation, and manifestations of this defect are recurrent thrombophlebitis and pulmonary embolism
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The extrinsic pathway is generally the first pathway activated in the coagulation process and is stimulated in response to a protein called tissue factor, which is expressed by cells that are normally found external to blood vessels. However, when a blood vessel breaks and these cells come into contact with blood, tissue factor activates factor VII, forming factor VIIa, which triggers a cascade of reactions that result in the rapid production of factor X. In contrast, the intrinsic pathway is activated by injury that occurs within a blood vessel. This pathway begins with the activation of factor XII (Hageman factor), which occurs when blood circulates over injured internal surfaces of vessels. Components of the intrinsic pathway also may be activated by the extrinsic pathway; for example, in addition to activating factor X, factor VIIa activates factor IX, a necessary component of the intrinsic pathway. Such cross-activation serves to amplify the coagulation process. The production of factor X results in the cleavage of prothrombin (factor II) to thrombin (factor IIa). Thrombin, in turn, catalyzes the conversion of fibrinogen (factor I)—a soluble plasma protein—into long, sticky threads of insoluble fibrin (factor Ia). The fibrin threads form a mesh that traps platelets, blood cells, and plasma. Within minutes, the fibrin meshwork begins to contract, squeezing out its fluid contents. This process, called clot retraction, is the final step in coagulation. It yields a resilient, insoluble clot that can withstand the friction of blood flow. | ||||
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| also spelled haemophilia hereditary bleeding disorder caused by a deficiency of a substance necessary for blood clotting (coagulation). In hemophilia A, the missing substance is factor VIII. The increased tendency to bleeding usually becomes noticeable early in life and may lead to severe anemia or even death. Large bruises of the skin and soft tissue are often seen, usually following injury so trivial as to be unnoticed. There may also be bleeding in the mouth, nose, and gastrointestinal tract. After childhood, hemorrhages in the joints—notably the knees, ankles, and elbows—are frequent, resulting in swelling and impaired function.
Persons with hemophilia are ordinarily advised to avoid activities that might expose them to bodily injury. The management of bleeding episodes includes infusions of clotting factor, which is derived from human blood or by recombinant DNA technology. The drug desmopressin (DDAVP) is useful in treating milder forms of hemophilia A. Hemophilia may also be attributed to a deficiency of factor IX (hemophilia B) or of factor XI (hemophilia C); hemophilia B (also called Christmas disease), like hemophilia A, is sex-linked and occurs almost only in males, whereas hemophilia C may be transmitted by both males and females and is found in both sexes. | |||
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hereditary transmission
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hemophilia: hereditary transmission 
(A) Mating of affected hemophilic man and normal woman—all sons normal, all daughters carriers. (B) Mating of carrier woman and normal man—half of sons normal and half affected; half of daughters carriers, half normal.
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hemophilia (Encyclopædia Britannica) hereditary bleeding disorder caused by a deficiency of a substance necessary for blood clotting (coagulation). In hemophilia A, the missing substance is factor VIII. The increased tendency to bleeding usually becomes noticeable early in life and may lead to severe anemia or even death. Large ...
Saturday, November 28, 2009
Isü Óji - Omenala ndi Igbo
Kola nut - Óji
Óji, is a native seed grown in the sultry forest. It is a seed which is planted and eaten in different regions in Nigeria. Óji is a prevalent seed in Nigeria and many other African-Caribbean countries, it is however of great significance in the Igboland.It is of great significance in the Igboland because the breaking, blessing and sharing of Óji is a tradition which has transcended from the progenitors. Our ancestors identified Oji as a very important seed which serve many purposes and which is why the seed is highly regarded and revered in the Igboland.
Óji plays a very important role in bringing a community together. The eating and sharing of kolanut is believed to bring harmony among those who partake in it. Those who partake in the blessing and sharing of kolanut are also believed to experience peace, unity, prosperity, reproduction and progress and many other blessings in their lives. Undoubtedly, one may begin to understand why so much value is attached to oji in the Igboland. Though it is a piece of nut as some may say, however, the attributes and benefits associated with the kolanut has placed it highly amongst those who partake in the sharing and blessing of the kolanut.
It would be interesting to note that kolanut is the first thing which is presented to guest in every Igbo gathering. Óji is served at many Igbo ceremonies such as marriages, new yam festivals, it is also used in settling disputes between siblings or neighbours as well as served at burials, however, the rhetoric rites are not performed during burials.
Different Parts of Igbo Kolanut (Óji Igbo)
The different lobes of kolanut range between two and seven and each lobe or segment symbolise something in the Igboland. It must however be noted that Igbo kolanut does not have two lobes; a kolanut with two segments is not served in the Igboland. Below are different kolanut lobes and what they symbolise.Óji Ato | ||
 | A kolanut with three lobes symbolises good relation. | |
Óji Ano | ||
 | A kolanut with four lobes is a symbol of progress and happiness, thus characterising the impending blessing which will be bestowed on those who partake in the blessing as well as eating of the nut. | |
Óji Ise | ||
| A five segments kolanut is a symbol of reproduction, thus symbolising the vast blessing which will follow those who eat it. It is said that the five segment nut is highly regarded amongst those who desire success in all spheres of their lives. It would be interesting to note that in the olden days when high importance was attached to large family, this type of kola nut was offered to men who had ample children. This was a mark of respect to them for having large family. Today, reproduction is not only seen in how many children one has, but, however in how successful one has attained in their respective field. Thus, the symbol of the five segment nut still holds strong to those who eat it as well as those who are present during the blessing of kolanut. | |
Óji Asa | ||
| A six or seven segment kolanut is a symbol of double progress, that is outstanding blessing. It is believed that anyone who partakes in eating of the kolanut will experience incessant progress in every area of his or her life. | |
WOMEN'S ROLE IN THE BREAKING OF KOLANUT
Tradition does not permit women to climb, pluck or break kola nut. A wife may present kola nut to her husband to offer to their guest, but under no circumstance must she break or bless the kola nut. The primary reason for this is that kola nut epitomises headship, hence, requiring the need for the husband to bless and break the nut. In the absence of the head of the household, any available man will be called upon to break the kolanut.Presentation of kola nut
It is the onus of an elderly man from the host family to present kola nut to his guest. It is however, the duty of the traditional ruler of Amaigbo (His royal Highness Eze Nwosu) to present and bless kola nut if he is present at any ceremony in Amaigbo. This also epitomises his headship as Amaigbo traditional ruler.Usually, when kola nut is presented to guests, an elderly man from the guest family would touch the kola nut and say to the host "Òji eze nò eze na aka", this means that the guests have seen the kolanut which has been presented to them and that the host should proceed to break and bless the nut. The elderly man could proceed to break the kola nut himself or designate the task to a younger man from his family. Where someone other than the elder himself broke the kola nut, it is later passed on to the elderly man for prayers and or blessings.
Blessing of kola nut
It is the Igbo believe that Oji does not speak or hear English, hence the dictum "Oji anaghi anu bekee". The elder or Eze then blesses the kola in Igbo lingua franca. He offers a piece of the kola nut to ancestral spirits and deities of the land and takes a piece himself; he dips the nut in okwa ose (or he can eat it with ose oji) before the rest is served to guest. These act are a mark of respect to the ancestral spirit, a symbol of the king’s headship as the leader of the community and a gesture to the guests that the host is happy to have them in her midst.The myth and custom of kolanut is one of the many sacred tradition transcended from the ancestors and one that will not be wiped out. The practice and adherence to the custom continues to bring unity to those who hold strong to it, it continues to foster peace in families as well as bring revenge to those who offer it to the ancestral spirits and gods for protection and justice.
 This is a picture of a mud house in an Igbo village. Notice the cement blocks in the front of the house implying that this mud house may be soon replaced by a new/modern house. | Igbo People http://www.lioness.cm.utexas.edu:80/I-files/Igbo.dir including links to essays contributed by chuksun@ssimicro.com: - Igbuagha Okuko (Naming/Thanksgiving Ceremony) http://www.lioness.cm.utexas.edu/I-files/Igbo.dir/Culture/chuk1.htm - Ihanyekwa nwanyi (Retaining a daughter for procreation in the family) http://www.lioness.cm.utexas.edu/I-files/Igbo.dir/Culture/chuk2.htm - Women Climbing the Palm Tree http://www.lioness.cm.utexas.edu/I-files/Igbo.dir/Culture/chuk3.htm |
Igbo Residence
In the traditional Igbo arrangement, men attemptto develop large households in order to gain prestige and influence within the community. A household head as such receives the important designation of ezi, and the head of a “big compound” is considered a major leader in village affairs. As in the Turkish system of patrilocality, the lifelong residential attachment of sons formed an important mechanism for increasing household size. However the Igbo utilize the additional principle of polygyny to substantially extend the capacity of their domestic unit. Unlike the Turkish system, a man’s second and subsequent wives remain resident in his compound to provide an expanded base for him to acquire dependents. Each is given a separate area within the larger structure in which they receive a hut for personal use and a surrounding area where their grown sons and daughters-in-law will eventually set up their own huts.The husband may have a separate hut, which is primarily used as a reception area, but he normally sleeps in one of his wives rooms according to a scheduled rotation.
Igbo Household Formation: Stage I
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A is married to two wives (B and C) each of whom is assigned a separate hut within the compound where she lives with her children
Each wife’s complex forms a separate social and economic unit, as well as a spatial one. It is designated as an umunne as apposed to the umunna, which covers the larger compound. As sons are married they bring their wives into their mother's section of the compound and assign huts to them. If they marry more than one wife, each gets a hut of herown for herself and her children. Stage II
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A's sons marry and bring in their wives, each of whom is assigned a new hut.
His daughters move out as they marry.
His daughters move out as they marry.
Stage III
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The same processes are repeated in the next generation
All the umunna members cooperate in some joint tasks, usually the cultivation of “men’s crops”, including yams and oil palms. The “women’s crops” are the responsibility of each wife on her own. The head of the household shares the proceeds from joint production among his wives, but each woman is allowed autonomous control of her own produce and any income it yields. She will usually use her resources to provide for her own children within the umunne, for whom she holds the primary care and feeding responsibilities. The separate status of the umunne was also important for the unity of full siblings, which forms the basis for the dynamic of household segmentation. At the death of a compound head, his sons can reorganize the domestic group in a number of ways. The assets can be divided among all the brothers, each of whom will establish a new unit. However, at least some of them will often remain together. On occasions half-brothers are able to cooperate and leave the unit completely intact under the leadership of the eldest, the okpara, the father’s main heir. More often, a group of full brothers, who constitut a single umunne, separate from the other full sibling groups within the compound. The senior branch, headed by the okpara would usually occupy the existing homestead and the others would general be responsible for founding new ones.
Household Segmentation
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Growth in a Segmented Household
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Note that E's sister's son has joined his household, an exception to the patrilocal rule that can occur in Igbo society.
The structure of polygyny and sibling unity in traditional Igbo society create households that are quite different in size, organization, and dynamics than the Turkish patrilocal pattern. They are larger with a more complex internal structure. For particularly prominent men, their scale can be increased even further through the addition of sister’s sons, with whom they maintain a special relationship, slaves, and other economic dependents such as apprentices and the number of residents could exceed a hundred. Household dynamics also has an implication for those of the wider descent system. Typical domestic division between groups of full brothers established the basis for segmentation within the lineage system. As a separate compound, each sibling group would become a new minor lineage. (Paradoxically, this patrilineal segment is actually establish by descent from a female ancestor.) All of the new compounds that formed from the defunct one would become constituted as a new major lineage.
The contrast between Igbo and Turkish patrilocal patterns are representative of general differences between the African and Eurasian social orders. It can in part be explained according to differences in the basic conditions of tribal and peasant societies. In the former case, the open availability of land and the land intensive production regime put a premium on the direct domestic control of labour. Accordingly, large households tend to form. The only limit to their size is the complexity of managing them, which is partly met by the Igbo system of delegating responsibility to domestic sub-units. In the later case, land is in short supply and households have fixed allotments that cannot be expanded. Accordingly, domestic units cannot growth beyond a fairly low threshold.
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