Ekstraselüler kayıt ve 'Suction' yöntemleri kullanılarak kaydedilen siyatik siniri bileşik aksiyon potansiyellerinden iletim hız dağılımı belirlenmesinin karşılaştırmalı olarak araştırılması
The Comparative investigation of conduction velocity distribution of compound action potentials of sciatic nerve trunk recorded by extracellular and suction recording techniques
- Tez No: 88990
- Danışmanlar: PROF.DR. FERİT PEHLİVAN
- Tez Türü: Doktora
- Konular: Biyofizik, Biophysics
- Anahtar Kelimeler: Ekstraselüler Yöntemi, Siyatik Siniri, Suction Yöntemi, Extracellular Techniques
- Yıl: 1999
- Dil: Türkçe
- Üniversite: Ankara Üniversitesi
- Enstitü: Sağlık Bilimleri Enstitüsü
- Ana Bilim Dalı: Biyofizik Ana Bilim Dalı
- Bilim Dalı: Belirtilmemiş.
- Sayfa Sayısı: 122
Özet
89 ./;('-î-/) /=ı bağıntısında, t. i. ci grup için gecikme zamanını, w. ise olasılık yoğunluk sabitini göstermektedir. Ekstraselüler ve suction yöntemleri ile kaydedilen BAP(t,x) sinyallerinden lif çapı histogramını oluşturmak üzere x=2 cm den kaydedilen sinyaller, yukarıdaki eşitlikte yerine konularak matris çözümleri için her bir lif grubunun olasılık yoğunluk sabitleri (w.) belirlenmiştir. Olasılık yoğunluk sabiti wi; A(dj), i. gruptaki TLAP genliklerinin wj üzerindeki etkisini; H(m0, i. gruptaki lif sayısının yoğunluk sabitine etkisini (m{, i. gruptaki aktive edilmiş lif sayısı) göstermek üzere, w^A^.Hfaj) şeklinde tanımlanabilmektedir. Belirlenen Wj olasılık yoğunluk sabitlerinden H(m) lif sayısal dağılımına geçebilmek için A(d)=d^ şeklinde olduğu kabul edilen genlik-lif çapı ilişkisinin bilinmesi gerekmektedir. En olası üssün p=l,6 olduğu varsayılarak, suction ve ekstraselüler kayıtlardan lif dağılım histogramlan belirlenmiş ve histolojik bulgularla karşılaştın lmıştır. Ekstraselüler kayıt yönteminden belirlenen lif dağılımları, suction yöntemine göre histolojik bulgularla daha sıkı bir uyum götermiştir.
Özet (Çeviri)
91 7-SUMMARY The Comparative Investigation of Conduction Velocity Distribution of Compound Action Potentials of Sciatic Nerve Trunk Recorded by Extracellular and Suction Recording Techniques. The analysis of compound action potential (CAP) of the peripheral nerve trunk after supramaximal electrical stimulation has become a standard tool for investigation of the function of the nerve trunks, for studies of nerve growth, development and regeneration, for obtaining of the distribution of nerve conduction velocity, and so for the evaluation of peripheral nerve diseases. Compound action potential of isolated nerve trunk can be recorded either by extracellular or suction recording techniques. We have recorded compound action potentials (CAPs) in frog sciatic nerve trunks with both using extracellular and suction recording techniques to determine which method gives the more reliable results for estimating the distribution of fiber diameters. In suction technique, the thin side of a nerve trunk was drawn snugly into the barrel of a saline- filled glass capillary (suction electrode) by the application of negative pressure (suction) into the capillary's free end. Suction electrodes were prepared from a low melting point glass capillary tube by heating in the middle point and then pulling away from the two sides under very high speed. The diameter of the tip of each electrode has been reset with respect to the size of the nerve trunk under investigation. The positions of the stimulating electrodes were changed to record from different distances. In extracellular action potential recording technique, nerve trunks were positioned on the recording and stimulating electrodes in the nerve chamber. Supramaximal stimulus has been delivered to the thin end (proximal end) of the nerve trunk to excitation of it. Position of the recording electrodes has been chanced to get the CAP recordings from different distances to the stimulating point. In monophasic extracellular recording, the integrals of the CAPs should be constant as the recording distance gets increase from the stimulating point, but since the geometric properties of the nerve trunk and changing the extracellular resistance between recording and stimulating electrodes, the integrals of the CAPs integrals decrease with the distance. In order to compensate the effects of this factor in the recordings, we defined a correction factor, g(x), and then we multiplied the CAPs recorded with extracellular technique with g(x). So, the integrals of corrected compound action potentials (cCAPs) were recalculated from our recordings. The amplitude of CAP recorded by suction electrodes is mainly determined by the resistance exist between suction electrodes and the nerve trunk. It is known that if mis resistance is infinite then an ideal recording can be obtained. Because of this, we have calculated the integrals of CAP vs. distance, and we constituted cCAP by determining g(x). We saw that this suction correction factors g(x) dose not deviate as that of extracellular g(x) factors and there is no need to use correction factors for suction CAP records It is known that the slope of maximum derivatives of CAPs versus distance curves which are approximately straight lines, is a measure of conduction velocity distribution of individual axons and so of their diameter distribution. We have determined the slopes of the maximum derivatives of CAPs recorded for the two recording techniques. With the values calculated from the slopes, we obtained that there is no important difference between the values of these two types of techniques. In this study, power spectrums of extracellular and suction recordings of CAPs have also been calculated by using Fast Fourier Analysis method, and then the change of power spectrums with distance were determined, and the results of these two techniques were compared.92 Since the fibers in a nerve trunk have different conduction velocities, it can be seen an increased temporal dispersion of the CAP's duration and a broadening in the CAP's shape as it propagates away from the stimulating point. So, die components of Fourier power spectrum changes as the recording point moves away from the stimulating point, the low frequency components dominates while the high frequency component being suppressed. For this reason it has been seen that the Fourier components of CAPs recorded by two techniques in the 0-100 Hz band increased with distance while the components in the 200-400 Hz band decreased. The slope of these variations may be regarded as another measure of the magnitude of the velocity distribution. But the slopes for the extracellular records were found higher than for the suction records, and it was another indicator that the extracellular method have a greater sensitivity for determining the fiber distribution. In theoretical studies related with CAP, first, a waveform for a single fiber action potential (SFAP) is defined for each fibers group in the problem type and called forward problem, then the total CAPs are constructed by taking into consideration of the SFAP waveform and its conduction time to different distances from the stimulating point. Our model study of SFAP waveform is defined as fCt)=Asin(t/T!).exp(-t/T2) where the parameters of Ti and %2 were calculated from SFAP duration given in the literature for each fiber diameter between d=3-22 um and A was determined by normalising the amplitude of SFAP to one. In our model study, relation between conduction velocity and fiber diameter has been used to calculate conduction velocities for certain diameters and the delay times for known distances of each fiber groups taking into account the temperature dependence of the conduction velocity. The equation that correlates recorded CAP and our model described as weighted sum of delayed SFAP is given as N BAIW-JX/iC-fi) where v, is the propagation delay for fibers in class i; Wj is the amplitude-weighting coefficient for class i; Ç(t) is the SFAP for conduction velocity of class i. In order to constitute fiber diameter histogram from CAPs(t,x) recorded at a distance 2 cm from the stimulating point by using either suction or extracellular techniques, CAPs have been put into above equation to derive w; from the solution of the matrices obtained for each group. The weighting coefficients (wO are general parameters to account for all influences on the contribution of each fiber classes to the observed CAP. Thus w* may be expressed as wf=A(vDH(im) where A(Vj): SFAP amplitude dependence on conduction velocity; H(nij): functional dependence of the weighting coefficients on the number of fibers in class i (m;: the number of activated fibers in class i). To derive numerical fiber histogram (H(m)), the relationship between conduction velocity and fiber diameter accepted as A(d)=dp should be known. Assuming p=1.6, we obtained fiber diameter distribution histogram from the recorded CAPs by both extracellular and suction techniques, and the results were compared with that of histological histograms. Fiber diameter histogram obtained from extracellular CAP coincide better with that of histological histograms than that of suction histograms.
Benzer Tezler
- Renal amiloidozis ve klinikopatolojik prognostik faktörler
Renal amyloidosis and clinicopathological prognostic factors
KEMAL KÖSEMEHMETOĞLU
Tıpta Uzmanlık
Türkçe
2009
NefrolojiHacettepe ÜniversitesiPatoloji Ana Bilim Dalı
PROF. DR. DİLEK ERTOY BAYDAR
- Koku alma tepkilerinin drosophila melanogaster'de intrapopulas yonal ve interpopulasyonal varyasyonu
Intrapopulational and interpopulational variation of olfactory responses in drosophila melanogaster
AYŞE GÜL MUTLU
Yüksek Lisans
Türkçe
1998
BiyolojiHacettepe ÜniversitesiBiyoloji Ana Bilim Dalı
PROF. DR. A. NİHAT BOZCUK
- Kardiyak al amiloidoz tanılı olgularda ekokardiyografik sol atrial strain ile mortalite arasındaki ilişkinin araştırılması
Investigation of the relationship between echocardiographic left atrial stenosis and mortality in patients with cardiac al amyloidosis
BEHİÇ ÇAĞLAR
Tıpta Uzmanlık
Türkçe
2024
KardiyolojiSağlık Bilimleri ÜniversitesiKardiyoloji Ana Bilim Dalı
PROF. DR. OMAÇ TÜFEKÇİOĞLU
- Rolandik epilepsi tanılı çocukların serum çinko düzeyinin değerlendirilmesi
Evaluation of serum zinc levels in children with rolandic epilepsy
DUYGU GÜNEŞ GÜL
Tıpta Uzmanlık
Türkçe
2023
Çocuk Sağlığı ve HastalıklarıSağlık Bilimleri ÜniversitesiÇocuk Sağlığı ve Eğitimi Ana Bilim Dalı
PROF. DR. MURAT ELEVLİ
DR. ÖĞR. ÜYESİ SENEM AYÇA
- Organik çözgenlere tolerant lipaz üreticisi mikroorganizmaların izolasyonu
Isolation of organic solvent tolerant lipase producing microorganisms
BİLGE HİLAL ÇADIRCI