وكالة

اردت عمل وكالة الى شخص ما. وبما انني قد عملت ذلك سابقا في هذه المدينة فقد كنت مطمئنا انني سانجز المهمة بكفاءة! في تجربتي السابقة وجدت ان الزحام عند الكاتب العدل المسائي اقل من الصباحي مما يجعل أنجاز الوكالة أسهل ولذلك أنطلقت بعد ظهر يوم شديد الحرارة من ايام صيف العراق المشهودة الى مكان الكاتب العدل. فوجئت بعدم وجود زحام بل لم ار شخصا واحدا على الباب مما اثار الشك في نفسي. دخلت المكان وتنقلت بين الغرف حتى قابلت شخصا يرتدي بجامة اخبرني ان الكاتب العدل قد انتقل الى مكان اخر. وبعد تحر واستفسار وانتقال من مكان الى اخر عرفت المكان الجديد واوقات العمل التي اختيرت بعناية لتكون في احر ساعات النهار (الواحدة الى الرابعة بعد الظهر). ذهبت بعد ظهر يوم اخر شديد الحرارة مثل سابقه فوجدت زحاما عرفت منه اننى اهتديت الى المكان الصحيح! لم ار كتاب العرائض الذين (لمن لا يعرف اجراءات العمل في دوائر الدولة العراقية) يخبرونك بما تحتاجه المهمة ويهيئون لك الأستمارة الخاصة والوثائق اللازمة لتأخذها الى الموظف المختص وتبدأ سلسلة التنقل من شباك الى شباك حتى تنجز المهمة (اذا لم تصادفك عقبة غير متوقعة توقف كل الاجراءات). سالت عن كتاب العرائض فدلوني على غرفة في الجانب الاخر من الشارع. ذهبت اليها فوجدتها غرفة ابعادها حوالي اربعة امتار في اربعة فيها شباك صغير واحد وليس فيها وسيلة للتبريد. يجلس داخلها ثلاثة كتاب عرائض وراء مناضدهم يحيط بهم حشد من المراجعين يملؤون الغرفة  الى بابها وكل منهم يستعمل اوراقه كمروحة يدوية يهزها امام وجهه الذي يتصبب عرقا. حشرت نفسي داخل الغرفة وبعد دقائق شعرت انني اوشك ان يغمى علي فخرجت. وبما انني أعرف من خبرتي السابقة ان كتاب العرائض عند الكاتب العدل الصباحي يعملون في مكان واسع مفتوح ومغطى وعددهم كبير حتى ان كل واحد منهم يحاول اغراءك بالمجيء عنده حالهم في ذلك حال كتاب العرائض في مختلف دوائر الدولة العراقية فقد قررت ان أذهب صباحا الى الكاتب العدل الصباحي لأهيأ الاوراق اللازمة عند أحد كتاب العرائض هناك ثم اتي بها مساء الى الكاتب العدل المسائي! وفي صباح اخر خرجت متوجها الى دائرة الكاتب العدل الصباحي وعند وصولى ألى المكان تفاجأت مرة اخرى بعدم وجود ازدحام وعدم وجود كتاب العرائض. وعندما سألت اخبروني ان الكاتب العدل انتقل الى مكان اخر! ولم استطع معرفة المكان الجديد بعد. في بلدنا تجاربك السابقة لا تفيدك! عدت الى البيت خائبا مرة اخرى وفي طريقى شاهدت بائع رقي (بطيخ في لغة بعض البلدان العربية الاخرى) ولكي اشعر نفسي بان خروجي لم يكن فاشلا تماما وقفت واشتريت رقية. وعندما وصلت البيت سألوني مثل كل مرة: هل أنجزت شيئا؟ قلت: نعم. اشتريت رقية! 

Are we copies of our previous selves?

On the same theme of the previous post (the dynamic steady state of our bodies), another thought may be entertained.

Our bodies are changing all the time and are in a tightly controlled balance with the environment. Every substance in the body is continuously lost and replenished. The input equals the output and the body remains in a steady state. Water which composes more than 60% of our bodies is lost through the kidneys, skin, lungs and intestine. It is replaced by the water we drink, water in our food and water produced in our bodies as a result of food metabolism. The water in our bodies today is not the same water that was in them days or weeks ago. The same thing applies to other elements and compounds that compose our bodies. Everything is lost and replaced by a new thing continuously. After a time the whole body has been replaced keeping the same design; the same architecture imposed and governed by our genes. Slow and gradual changes in design occur as a result of aging. Rapid changes occur sometimes as a result of disease and accidents. In other words every one of us is not exactly the same person he was sometime ago. He is a copy of his previous self. If you see a friend that you have not seen for a year you are in fact not seeing him but seeing a copy of him! To be more precise a copy of you is seeing a copy of him!! A somewhat disturbing idea to sleep on if you are reading this article late at night.

Kidney failure and the steady state of our bodies

When I told a group of students that the kidneys of a patient with kidney failure whose condition is stable excrete normal amounts of waste products and other substances like normal kidneys, they responded with a kind of disbelief: why then does the patient develop manifestations of kidney failure and why do we call it kidney failure?!

The answer is this.

If a patient or a person is in a steady state i.e. he or she is the same and his plasma urea and creatinine are the same today, tomorrow or after a week, then the input of any substance (entering or produced in his body) must be equal to the output. In the case of urea and creatinine the production in the body by tissues must be equal to the amount excreted by the kidneys. In other words if the blood urea and creatinine are constant over a period of time (regardless of whether they are in the normal level or elevated) then his kidneys must be excreting all that is produced, otherwise the level must rise. The critical point here is that the failing kidneys excrete normal amounts in spite of their reduced glomerular filtration because the level of the substance in the blood, and consequently in the filtrate, is high; so a reduced volume of glomerular filtrate contains the same amount of urea or creatinine as a larger volume with a lower concentration. If for some reason kidney function deteriorates and filtration drops further then the balance between production and excretion is disturbed. Urea and creatinine start to rise. The patient now is not in a steady state. The level goes on rising resulting in increased excretion until the amount excreted in the reduced volume of filtrate becomes equal to the production. The rise in the serum level stops and the patient reaches a new steady state at a higher level of plasma urea and creatinine. In other words failing kidneys excrete normal amounts of various substances on the expense of a higher plasma concentration of these substances.

To make an analogy, think of a tank with a hole in the bottom and water flowing into it from a tap. The level of water in the tank depends on the balance between the water flowing in and that flowing out. If the hole in the bottom is made smaller the balance is disturbed, the inflow exceeds the outflow causing the level in the tank to rise. The rising level increases the pressure driving the water out from the smaller hole. The water outflow starts increasing. The change goes on until the outflow becomes equal to the inflow. The level of water in the tank then stops rising and stabilizes at a new higher level assuming a new steady state.

The ability of our bodies to keep their composition and various characteristics constant (i.e. in steady states) is remarkable. Think of body temperature, body weight, the number of various blood cells, skin cells, intestinal cells, the amount of water in our bodies, the amount and concentration of various chemical substances in our tissues etc. etc. Everything is kept in a steady state; a dynamic, not static, steady state. The essence of it is to equalize the input and output.

Inverse epidemiology

It is a common knowledge that high body weight, high blood pressure, high blood sugar and high blood cholesterol are detrimental to health. In epidemiological studies (studies of disease in the community) the higher these are the higher the illness (morbidity) rate and death (mortality) rate. Put in a different way the lower they are the lower the illness and death rates. The relationship is a direct relationship. But is that always the case? Do illness and death rates go on decreasing with decreases in these variables without limits? Is a body weight of 40 kg. better than a body weight of 60 kg. or a blood pressure of 70/30 better than 100/60? Obviously not. A decrease in these variables is associated with a decrease in illness and death rates within certain limits. After reaching optimum levels the relationship becomes inverted and lower figures are associated with higher illness and death rates. The epidemiology is now inverse (so called).

I must say I came across the term “inverse epidemiology” for the first time when reading about the relationship between blood pressure and cardiovascular outcome in patients with end stage renal disease on maintenance hemodialysis. I am not sure of the use of the term in the general sense I described earlier. But it seems to me it applies just the same outside the situation of patients on dialysis and outside the subject of blood pressure.

In fact it also applies to aspects of life outside the field of medicine. Direct relationship becomes inverse after certain limits. Too rich, too powerful, too beautiful etc. may become a curse rather than a blessing!!