THOUSANDS OF FREE BLOGGER TEMPLATES ?

Rabu, 23 September 2009

Sindrom Ovarium Polikistik (SOPK)


Pendahuluan:
Pembahasan SOPK berikut ini meliputi 9 hal, yaitu:
1. Anatomi ovarium
2. Histologi ovarium
3. Sinonim SOPK
4. Definisi SOPK
5. Penyebab SOPK
6. Diagnosis SOPK
7. Terapi SOPK
8. Komplikasi SOPK Jangka Panjang
9. Catatan


Anatomi ovarium


Secara makroskopis, ovarium menyerupai buah pir, dengan ukuran yang bervariasi, tergantung usia.

Pada usia reproduksi, ukuran ovarium:
panjang: 2,5–5 cm
lebar: 1,5–3 cm
tebal: 0,6–1,5 cm

Normalnya, ovarium terletak di bagian atas rongga pelvis, bersandar sedikit inferior dari dinding lateral pelvis pada daerah percabangan pembuluh darah iliaka eksternal dan internal, yakni fossa ovarika Waldeyer. Posisi ini sangatlah bervariasi dan biasanya berbeda antara ovarium kiri dengan kanan.

Masing-masing ovarium mengandung sejumlah folikel primordial yang berkembang pada saat awal kehidupan fetus dan menunggu saat pematangan menjadi ovum. Selain memproduksi ovum, ovarium juga menghasilkan hormon seksual.

Perlekatan:
Ovarium terletak di sebelah dinding samping pelvis dan ditahan pada posisi ini oleh dua struktur: ligamentum latum yang melekat ke ovarium di sebelah posterior oleh mesovarium, dan ligamentum ovarika yang menahan ovarium ke kornu uterus.

Ovarium dilekatkan pada ligamentum latum oleh mesovarium. Ligamentum ovarii proprium berjalan dari uterus lateral posterior hingga ke bagian bawah ovarium. Panjangnya beberapa cm dengan diameter 3-4 mm. Ligamentum ini diselimuti oleh peritoneum dan terdiri dari jaringan ikat dan otot yang berasal dari bagian uterus.

Ligamentum infundibulopelvikum berjalan dari bagian ovarium yang menghadap tuba hingga ke dinding pelvis, tempat pembuluh darah dan persarafan ovarium berjalan di dalamnya.

Pasokan darah:
Dari a.ovarika (cabang aorta abdominalis). Drainase vena menuju v.kava inferior di sebelah kanan dan v.renalis sinistra di sebelah kiri.

Drainase limfatik:
Menuju kelenjar getah bening para-aorta.

Histologi Ovarium

Struktur ovarium secara umum dibagi dua: korteks dan medula.

Tiap ovarium dikelilingi oleh kapsula fibrosa, yang disebut tunika albuginea. Tunika albuginea ini merupakan permukaan terluar korteks. Di atas tunika albuginea terdapat epitel kuboid selapis, epitel germinativum Waldeyer.

Medula merupakan bagian tengah yang terdiri dari jaringan ikat longgar yang merupakan kelanjutan dari mesovarium. Pada medula banyak terdapat pembuluh darah dan sedikit jaringan otot halus yang merupakan kelanjutan dari ligamentum infundibulopelvikum.

Sinonim SOPK:

Sindrom ovarium polikistik, polycystic ovarian syndrome.

Definisi SOPK:

Kumpulan gejala yang ditandai dengan adanya anovulasi (tidak keluarnya ovum/sel telur) kronis (yang berkepanjangan/dalam waktu lama) disertai perubahan endokrin (seperti: hiperinsulinemia, hiperandrogenemia).

Penyebab SOPK:

1. Resistensi insulin
2. Hiperandrogenemia
3. Kelainan produksi hormon gonadotropin
4. Disregulasi P450 c 17
Defek gen pembentuk P450 c 17α, yang mengkode aktivitas 17α-hidroksilase dan 17,20-lyase.
5. Genetik
Ada kecenderungan penurunan sifat secara autosomal dominan.

Diagnosis SOPK:

1. Kriteria Klinis
Hirsutisme (tumbuhnya rambut tubuh yang berlebihan), akne, obesitas/kegemukan (sangat tidak spesifik), oligomenore (menstruasi yang jarang), amenore (tidak menstruasi), perdarahan uterus disfungsi, dan infertilitas.

Konsensus Diagnostik menurut konferensi National Institute of Health (NIH) di Amerika Serikat:

a. gambaran ovarium polikistik tidak harus ada.
b. Kriteria mayor: anovulasi kronis dan hiperandrogenemia.
c. Kriteria minor: adanya resistensi insulin, hirsutisme, obesitas, rasio LH/FSH lebih dari 2,5 dan gmbaran ovrium polikistik pada USG.

Diagnosis SOPK ditegakkan jika memenuhi SATU kriteria mayor dan sekurngnya DUA kriteria minor, dengan menyingkirkan penyebab lain hiperandrogenemia.

Konsensus Diagnostik menurut negara di Eropa:
a. Harus didapatkan gambaran ovarium polikistik dengan USG
b. Gangguan menstruasi (oligomenore atau amenore), dan atau
c. Gambaran klinis hiperandrogenemia (hirsutisme, akne)
d. Tidak diperlukan pemeriksaan laboratorium untuk menegakkan iagnosis SOPK.

Kriteria praktis dari Homburg (2002):

1. Kriteria awal yang harus ada:
a. Gangguan menstruasi
b. Hirsutisme
c. Akne
d. Infertilitas anovulasi

2. Diagnosis ditegakkan cukup dengan memperoleh gambaran ovarium polikistik pada USG.

3. Jika tidak ditemukan gambaran ovarium polikistik pada USG, maka dilakukan pemeriksaan laboratorium. Diagnosis SOPK dapat ditegakkan jika ditemukan satu/lebih abnormalitas: peningkatan testosteron serum, peningkatan LH (luteinizing hormone), peningkatan testosteron bebas (dengan menyingkirkan hiperplasi adrenal), perbandingan glukosa puasa:insulin puasa kurang dari 4,5.

2. Kriteria Ultrasonografis (USG)

Kriteria diagnostik jika memakai USG transabdominal:
1. Penebalan stroma
2. Lebih dari 10 folikel berdiameter 2-8 mm di subkorteks dalam satu bidang.

Kriteria diagnostik jika memakai USG transvaginal:
1. Penebalan stroma 50%
2. Volume ovarium lebih dari 8 cm3
3. Lebih dari 15 folikel dengan diameter 2-10 mm dalam satu bidang

3. Kriteria Laboratorium

Pemeriksaan kadar hormon androgen, insulin, dan LH/FSH (Luteinizing Hormone/Follicle-Stimulating Hormone)

Kadar androgen yang dapat diperiksa adalah: testosteron, androstenedion, testosteron bebas, dehidroepiandrosteron (DHEA) atau dehidroepiandrosteron sulfat (DHEAS), dan dehidrotestosteron (DHT).

Terapi SOPK:

1. Penurunan berat badan, diet, dan olahraga

2. Obat antidiabetik oral
Misalnya: metformin, troglitazone, rosiglitazone, pioglitazone, chlorpropamide, tolazamide, glipizide, D-chiro-inositol.

3. Obat pemicu ovulasi
Misalnya: klomifen, human menopausal gonadotrophin (hMG), purified FSH, recombinant FSH, bromocriptine, dan gonadotrophin releasing hormone (GnRH).

4. Pembedahan (surgery)
a. EBOB (Eksisi Baji Ovarium Bilateral)
b. TEKO (Tusukan ElektroKauter pada Ovarium)

Terapi TEKO dengan laparoskopi lebih baik dibandingkan dengan EBOB karena angka perlekatan pascoperasi yang lebih rendah.

Komplikasi SOPK Jangka Panjang:

1. Diabetes Melitus tipe 2
2. Dislipidemia
3. Kanker endometrium
4. Hipertensi
5. Penyakit kardiovaskular
6. Gestational DM
7. Pregnancy-induced hypertension (PIH)
8. Kanker ovarium
9. Kanker payudara

Catatan:

1. Diperkirakan 8 juta wanita usia subur menderita gangguan ovarium polikistik.

2. Penyebab terbanyak keadaan anovulasi kronis adalah sindrom ovarium polikistik.

3. Ovulasi merupakan proses menghasilkan ovum yang dapat dibuahi, melibatkan susunan saraf pusat supra hipotalamus, hipofisis, dan ovarium sebagai organ target.

4. Ovulasi dipicu oleh peningkatan cepat kadar estrogen.

5. Ovulasi terjadi 10-12 jam setelah terjadinya lonjakan LH dan 24- 36 jam setelah tercapainya kadar puncak estrogen.

6. Resistensi insulin dapat dinilai dengan pemeriksaan:

a. uji toleransi glukosa oral
Keuntungan:
Mudah dikerjakan.
Kerugian:
Dipengaruhi penyerapan glukosa usus.

b. uji toleransi insulin
Keuntungan:
Dapat menunjukkan indeks aktivitas insulin.
Kerugian:
Dapat terjadi hipoglikemia.

c. Infus glukosa berkesinambungan
Keuntungan:
Dapat menunjukkan kerja insulin.
Kerugian:
Bergantung pada validitas tera.

d. Teknik klem euglikemik
Keuntungan:
Dapat mengukur kerja insulin secara kuantitatif.
Kerugian:
Mahal dan sulit.

e. Nisbah gula darah puasa atau insulin puasa
Keuntungan:
Mudah dikerjakan.
Kerugian:
Dipengaruhi oleh kadar gula darah sewaktu.

Inflamasi Kronik Tak Berkaitan dengan Kanker Ovarium


Hasil studi yang dipublikasikan International Journal of Cancer menduga bahwa kebanyakan faktor yang menyebabkan inflamasi di ovarium tidak berkaitan dengan peningkatan risiko kanker ovarium.

Sebelumnya inflamasi kronik diduga berkaitan dengan mekanisme perkembangan kanker ovarium epital, seperti inflamasi rongga panggul (pelvic inflammatory disease) atau penggunaan bedak di sekitar pelvik.
Tumor epitel ovarium, yang merupakan 90% dari semua jenis kanker ovarium, terbentuk di sel-sel epitel, yakni sel yang menutup permukaan luar ovarium. Jenis-jenis tumor umumnya dinamai berdasarkan jenis sel tempat mereka tumbuh pertama kali. Di dalam kategori tumor epitel, kanker ovarium diklasifikasikan sebagai serous, mucinous, endometrioid dan tipe sel jernih, dengan tumor jenis serous sebagai yang tersering ditemukan.

Peneliti dari Queensland Institute of Medical Research, Brisbane, Australia, menguji faktor-faktor yang berpotensi menimbulkan peradangan ovarium. Penelitian dilakukan pada 1.576 perempuan dengan tumor invasif dan tumor non-maligna, serta 1.509 subjek pada populasi umum.

Penggunaan bedak talk (talcum powder) di pelvik dikaitkan dengan peningkatan risiko semua jenis kanker ovarium. Peningkatan risiko terlihat lebih kuat untuk tumor jenis serous dan endometrioid, namun yang secara statistik signifikan hanya jenis tumor serous. Anehnya tidak ada kaitan antara infeksi pelvic, HPV atau mumps dengan risiko kanke rovarium secara keseluruhan. Riwayat herpes genital juga tidak berkaitan dengan peningkatan risiko kanker ovarium.

Pada studi lain, riwayat endometriosis juga meningkatkan risiko hingga dua kali lipat terjadinya tumor endometrioid dan risiko tumor ovarium tipe sel jernih lebih tinggi. Peneliti berkesimpulan, inflamasi kronik tidak memegang peran utama dalam perkembangan kanker ovarium.

sperma cell


A sperm cell is one of the most specialised cells in the animal body. They arise by repeated mitosis followed by meiosis to produce haploid immature sperm cells, each with a different genotype (if the process was meiosis followed by mitosis all the cells would have the same genotype). This is spermatogenesis. The sperm mature in the epidydimis, but they do not become fully mature until they reach the female oviduct. They have three separate regions.

The Head.

This has two important features. The acrosome contains lytic enzymes which are released when the sperm reaches an ovum. These enzymes digest the outer membrane of the egg, allowing penetration of the sperm. The head also contains a single set of chromosomes derived from the male. This will include either an 'X' or 'Y' chromosome, because of the way the XY separate during meiosis.

The Middle Section.

This part, immediately behind the head, contains numerous mitochondria. These respire sugars in the semen to generate ATP in order to provide the energy for movement of the tail.

The Tail.

This contains microfilaments running the length of the tail (arranged in the usual 9 + 2 system seen in Eukaryotic organisms). Rhythmic contraction of the filaments causes the tail to wave and move against the fluid environment, providing forward motion.


Minggu, 06 September 2009

rutheford

Ernest Rutherford was born on August 30, 1871, in Nelson, New Zealand, the fourth child and second son in a family of seven sons and five daughters. His father James Rutherford, a Scottish wheelwright, emigrated to New Zealand with Ernest's grandfather and the whole family in 1842. His mother, Née Martha Thompson, was an English schoolteacher.

Ernest received his early education in Government schools and at the age of 16 went to Nelson Collegiate School. In 1889 he was awarded a University scholarship and he proceeded to the University of New Zealand, Wellington, where he entered Canterbury College. He graduated M.A. in 1893 with a double first in Mathematics and Physical Science and he continued with research work at the College for a short time, receiving a degree the following year. That same year, 1894, he was awarded an 1851 Exhibition Science Scholarship, enabling him to go to Trinity College, Cambridge, as a research student at the Cavendish Laboratory under J.J. Thomson. In 1897 he was awarded the B.A. Research Degree and the Coutts-Trotter Studentship of Trinity College. An opportunity came when the Macdonald Chair of Physics at McGill University, Montreal, became vacant, and in 1898 he left for Canada to take up the post.

john dalton


John Dalton was born in 1766. He was born into a modest family in Cumberland, England. He earned a living for most of his life as a school teacher and a public lecturer. After teaching 10 years at a boarding school in Kendal, he moved on to a teaching position in the city of Manchester. There he joined the Manchester Literary and Philosophical Society, which provided him with a stimulating intellectual environment and laboratory facilities. The first paper he delivered before the society was on color blindness, and died in 1844.

Dalton joined the Manchester Literary and Philosophical Society and immediately published his first book on Meteorological Observations and Essays.

In this way, Dalton was able to start working out a table of atomic weights based on the lightest element, hydrogen, having a value of 1. He used his ideas about the make up of gasses this way, "we may form an idea of this by supposing a vessel filled with small spherical leaden bullets among which a quantity of fine sand is poured. The balls are to the sand as the particles of bodies are with respect to the caloric; with this difference only, that the balls are supposed to touch each other, whereas the particles of bodies are not in contact, being retained at a small distance from each other by the caloric." (Dalton)

Dalton's thoughts on his research allowed him to develop his theory were All matter was made up of hard round particles, which he called 'atoms', and that each type of atom, or element, such as hydrogen, oxygen, nitrogen, etc., differed from the next only by its weight.

The atomic theory had been born....
But his next idea was one of equal genius, how to represent this idea symbolically so that tiny, invisible particles could be 'seen' and their combining properties studied.

The solution was that Dalton thought, was to draw circles, each circle representing one of his tiny atomic spheres. Each element could be notable by the contents of the circle.

j.j thompson




Joseph John Thompson better known as JJ Thompson, was born on December 18, 1856 near Manchester, England. His father died when "JJ Thompson" was only sixteen. JJ attended Owens College in Manchester, where his professor of mathematics encouraged him to apply for a scholarship at Trinity College, one of the most important of the colleges at Cambridge University. JJ won the scholarship, and in 1880 finished second in his class (behind Joseph Larmor) in the grueling graduation test in mathematics. Trinity gave him a fellowship and he stayed on there, trying to craft mathematical models that would reveal the nature of atoms and electromagnetic forces. He also died in 1940.




In 1897 Joseph John Thompson discovered the electron in a series of experiments designed to study the nature of electric discharge in a high-vacuum cathode-ray tube—an area being investigated by numerous scientists at the time. Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of "bodies much smaller than atoms" that he calculated as having a very large value for the charge to mass ratio. Later he estimated the value of the charge itself. In 1904 he suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. His efforts to estimate the number of electrons in an atom from measurements of the scattering of light, X, beta, and gamma rays initiated the research trajectory along which his student Ernest Rutherford moved. Thomson's last important experimental program focused on determining the nature of positively charged particles. Here his techniques led to the development of the mass spectroscope, an instrument perfected by his assistant, Francis Aston, for which Aston received the Nobel Prize in 1922.