Selasa, 25 Disember 2012

TOTAL BILIRUBIN

Unconjugated Bilirubin is a breakdown product of heme (a part of hemoglobin in red blood cells). Unconjugated bilirubin is very hydrophobic and relies on transportation on albumin that is circulating in the blood. This is why addition of high concentration hydrophobic drugs (certain antibiotics, diuretics) and high free fatty acids can cause elevated unconjugated bilirubin. Heme can also come from myoglobin, found mostly in muscle, cytochromes, found mostly in mitochondria, catalase, peroxidase, and nitric oxide synthase. 

The liver is responsible for clearing the blood of unconjugated bilirubin and about 30% of bilirubin is taken up by a normal liver each pass through the liver. It does this by the following mechanism: Bilirubin is taken up into hepatocytes, conjugated (modified to make it water-soluble) by UDP-glucuronyl-transferase, and secreted into the bile by CMOAT (MRP2), which is excreted into the intestine. In the intestine, conjugated bilirubin may be (1) metabolized by colonic bacteria, (2) eliminated, (3) reabsorbed. Metabolism of bilirubin into urobilinogen followed by reabsorption of urobilinogen accounts for the yellow color of urine as we urinate a downstream product of urobilinogen. Further metabolism of urobilinogen into stercobilin while in the bowels accounts for the brown color of stool. Thus having white or clay colored stool is an indicator for a blockage in bilirubin processing and thus potential liver dysfunction or cholestatis.

Increased total bilirubin (TBIL) causes jaundice, and can indicate a number of problems:  Prehepatic: Increased bilirubin production. This can be due to a number of causes, including hemolytic anemia  and internal hemorrhage.Hepatic: Problems with the liver, which are reflected as deficiencies in bilirubin metabolism (e.g., reduced hepatocyte uptake, impaired conjugation of bilirubin, and reduced hepatocyte secretion of bilirubin). Some examples would be cirrhosis and viral hepatitis.3. Posthepatic: Obstruction of the bile ducts, reflected as deficiencies in bilirubin excretion. (Obstruction can be located either within the liver or in the bile duct.

The diagnosis is narrowed down further by looking at the levels of direct bilirubin.If direct (i.e. conjugated) bilirubin is normal, then the problem is an excess of unconjugated bilirubin (indirect bilirubin), and the location of the problem is upstream of bilirubin conjugation in the liver. Hemolysis, viral hepatitis, or cirrhosis can be suspected.If direct bilirubin is elevated, then the liver is conjugating bilirubin normally, but is not able to excrete it. Bile duct obstruction by gallstones or cancer should be suspected.


About 5% of the population have Gilbert's disease, a mutation (or variation) in the UDP-glucuronyl-transferase promotor that manifests itself as jaundice when the individual is stressed (ie starves). Autosomal recessive knockouts of UDP-glucuronyl-transferase itself can lead to Crigler-Najjar Syndrome and elevations of unconjugated bilirubin. Defects in CMOAT (MRP2) results in Dubin-Johnson Syndrome and elevations of conjugated bilirubin.

Neonates are especially vulnerable to bilirubin levels due to an immature blood-brain barrier that predisposed them to kernicterus / bilirubin encephalopathy which can result in permanent neurological damage. Neonates also have a low amount of functional UDP-glucuronyl-transferase and can have elevated unconjugated bilirubin since conjugated is limited. For this reason, newborns are often treated with UV light to turn the hydrophobic, albumin-binding unconjugated bilirubin into a form that is more hydrophilic and able to be secreted out via urine, sparing the neonate's brain.

Jumaat, 11 Mei 2012

GIARDIA LAMBLIA


BALANTIDIUM COLI








TANDA-TANDA PENYAKIT ANEMIA

Anemia atau masalah kurang darah bukan perkara asing dalam masyarakat kita.
Secara mudahnya, anemia bermakna kekurangan sel darah merah. Darah boleh dibahagikan kepada tiga, iaitu:
  • Sel darah merah.
Sel darah merah pula meliputi hemoglobin (protein yang kaya zat besi dan berwarna merah). Tugasnya ialah membawa oksigen dari paru-paru ke organ dan karbon dioksida kembali ke paru-paru untuk dibebaskan ke udara.
  • Sel darah putih
Sel darah putih berfungsi sebagai sistem pertahanan menentang kemasukan bahan asing ke dalam badan.
  • Platlet dan plasma
Platlet pula penting untuk menghentikan pendarahan apabila luka.
Tanda-Tanda Anemia
Apabila seseorang itu mengalami masalah kulit pucat, degupan jantung pantas, cepat letih, sesak nafas, sakit dada, kerap berasa pening, sejuk dan kebas,  Cuba jelirkan lidah dan lihat warnanya. Adakah ia jauh lebih merah berbanding lidah ahli keluarga yang lain? Sekarang cuba perhatikan bahagian bawah mata dan tangan. Adakah ia berwarna pucat? Jika sebahagian atau semua tanda di atas ada, anda mungkin mengalami masalah anemia.


Bagaimana Anemia Boleh Terjadi?
Ia boleh berlaku disebabkan beberapa faktor, antaranya:
  • Badan kurang menghasilkan sel darah merah
  • Kehilangan terlalu banyak darah atau kadar kemusnahan sel darah berlaku lebih cepat daripada penghasilannya.
Faktor Penyebab Anemia
a) Kurang Penghasilan Sel Darah Merah Yang Disebabkan:
  • Masalah kekurangan zat besi
  • Kehilangan darah
  • Keracunan logam.
  • Gangguan pada sumsum tulang (myelodyspasia).
  • Penyakit kronik (kerosakan buah pinggang, kanser, artritis reumatoid, Sistemic Lupus Eritematosus, SLE) yang merencatkan fungsi sumsum tulang.
  • Penyakit haemofilia
b) Kemusnahan Sel Darah Merah Luar Biasa (Hemolisis)
  • Iaitu sel darah merah pecah dengan sendiri. Jika kemusnahan sel darah merah berlaku lebih cepat berbanding penghasilannya, individu itu akan mengalami masalah anemia. Hemolisis boleh disebabkan penyakit seperti:
c) Talassemia

d) Kekurangan enzim Glucose-6-Phosphate Dehydrogenase (G6PD).
e) Auto imun hemolitik
f) Penyakit sel sikel (masalah yang diwarisi)


 
Masalah Sel Darah Merah:
  • Leukemia
  • HIV
  • Neutropenia
Cara Untuk Mengelak Anemia
Secara asasnya, pemakanan harian seimbang iaitu yang cukup sukatan sayur dan sumber protein. Ia penting kerana pemakanan yang seimbang mampu mengatasi masalah kekurangan darah. Maknanya, seseorang itu akan dapat zat besi, vitamin B12 dan folat mencukupi. Seterusnya, pengambilan zat besi. Zat besi boleh diperoleh daripada sayur-sayuran hijau (juga kaya dengan folat), daging merah dan organ (seperti hati).
Daging merah dan organ dalaman juga tidak diambil berlebihan, terutama bagi individu yang ada masalah jantung dan paras kolesterol tinggi, kerana ia turut mengandungi banyak vitamin B12 yang boleh menyebabkan keracunan hati.

Kesimpulan
Anemia bukan penyakit, tetapi satu masalah yang boleh mengganggu tugas harian. Orang yang mengalami masalah anemia cepat berasa letih dan tidak boleh bergiat dalam aktiviti cergas. Amalan pemakanan seimbang dan kaya zat besi biasanya boleh merendahkan risiko mengalami masalah kurang darah.

Rabu, 14 Mac 2012

LIFE CYCLE OF BRUGIA MALAYI

The typical vector for Brugia malayi filariasis are mosquito species from the genera Mansonia and Aedes. During a blood meal, an infected mosquito introduces third-stage filarial larvae onto the skin of the human host, where they penetrate into the bite wound. They develop into adults that commonly reside in the lymphatics. The adult worms resemble those of Wuchereria bancrofti but are smaller.
Female worms measure 43 to 55 mm in length by 130 to 170 μm in width, and males measure 13 to 23 mm in length by 70 to 80 μm in width. Adults produce microfilariae, measuring 177 to 230 μm in length and 5 to 7 μm in width, which are sheathed and have nocturnal periodicity. The microfilariae migrate into lymph and enter the blood stream reaching the peripheral blood. A mosquito ingests the microfilariae during a blood meal.

After ingestion, the microfilariae lose their sheaths and work their way through the wall of the proventriculus and cardiac portion of the midgut to reach the thoracic muscles. There the microfilariae develop into first-stage larvae and subsequently into third-stage larvae. The third-stage larvae migrate through the hemocoel to the mosquito's prosbocis and can infect another human when the mosquito takes a blood meal.