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Biomedical subjects

B Uludağ

Publications and source records attributed to B Uludağ.

16 recordsLinked to original sources
PubMed1998

Surface stimulation single-fiber electromyography.

Stimulation single-fiber electromyography (S-SFEMG) is an alternative method to SFEMG during voluntary contraction (VC-SFEMG). S-SFEMG is preferred to VC-SFEMG in uncooperating patients, children, and patients having severe weakness. Surface stimulation is a viable alternative to needle stimulation in S-SFEMG. In the present study, surface versus needle stimulation of facial nerve has been tested by recording from the orbicularis oculi and frontalis muscles. Jitter values obtained by both methods have been found to be nearly equal.

Adult↗
PubMed1998

Effect of the vastus medialis obliquus on the patellofemoral joint.

In this study, the effect of dynamic stabilizers on the patellofemoral (PF) joint was investigated in normal volunteers (group I) and in patients with patellar pain (group II) or instability (group III) by using computed tomography (CT) analysis and integrated electromyography (iEMG) of the quadriceps muscle. Nine subjects (16 knees) from group I, 10 patients (12 knees) from group II and 8 patients (12 knees) from group III were included in the study. CT scans of the PF joint with quadriceps contracted (QC) and uncontracted (QU) and iEMG of vastus medialis obliquus (VMO), vastus lateralis (VL) and rectus femoris (RF) were obtained with the aid of a specially designed jig at 0 degree, 15 degrees, 30 degrees and 45 degrees of knee flexion. The same muscle contraction pattern simulating closed kinetic chain exercise was used for both CT and iEMG. The difference between the congruence angles (CA) and tilt angles (PTA) in QC and QU positions and VMO:VL ratio from the iEMG were calculated separately for each flexion angle. CA was increased in all groups with quadriceps contraction at 0 degree and 15 degrees of flexion. PTA was decreased in group I and increased in groups II and III with quadriceps contraction at the same flexion angles. This difference was statistically significant in group III at 0 degree and 15 degrees of flexion. Quadriceps contraction did not affect the patellar position significantly even in the instability group at 45 degrees of flexion. In all flexion angles the balanced VMO:VL activity ratio was observed only in group I. In the other groups, VL activity was higher than VMO activity except at 45 degrees of flexion. These findings do not support the hypothesis of dominant centralizing effect of VMO on the patella in extension, but the effect of the VMO may be more clearly demonstrated by measuring PTA in both QC and QU positions.

Adult↗
PubMed1997

Ulnar nerve lesion in the palm: report of an unusual case.

We report the case of a patient who had weakness of the fourth dorsal interosseous (DI) and third palmar interosseous (PI) muscles resulting in the abducted position of the little finger at rest. Electromyographic abnormalities were limited to only these muscles with partial denervation findings. The results of routine nerve conduction studies and imaging techniques were normal. Clinical and electrophysiological findings suggested that the lesion had occurred distal to the point where the very small motor branches to these muscles exit the deep palmar branch of the ulnar nerve.

Action Potentials↗
PubMed1997

A special kind of anterior horn cell involvement in juvenile myoclonic epilepsy demonstrated by macro electromyography.

Juvenile myoclonic epilepsy (JME) is not an uncommon seizure disorder, occurring in 5-10% of epileptic patients. A subclinical anterior horn cell involvement has been suggested in some JME patients by concentric needle electromyography (EMG) and turn/amplitude analysis. In this study, 22 JME patients and 17 normal control subjects have been studied with macro EMG, which is a sensitive method to assess the size of motor units. Most JME patients (19 of 22) had a pathologically increased number of individual large macro motor unit action potentials (MUAPs) compared to control subjects. For both biceps brachii and tibialis anterior muscles, means of median macro MUAP amplitudes were significantly greater than those of normal controls, whereas the fiber density values were only slightly increased. This suggested another kind of anterior horn cell involvement in JME than seen in motor neuron diseases.

Action Potentials↗
PubMed1997

Effects of bolus volume on oropharyngeal swallowing: an electrophysiologic study in man.

OBJECTIVE: Different variables of oropharyngeal swallowing change in response to bolus volume and consistency as determined by manometric/videofluoroscopic studies. But the subject is debatable especially from the physiologic point of view. No electrophysiologic studies are available on human subjects. METHODS: The effects of bolus volume and viscosity on different variables of oropharyngeal swallowing were investigated using electrophysiologic methods. Mechanical upward and downward laryngeal movements and submental electromyographic (SM-EMG) activity of the laryngeal elevator muscles were recorded during dry and 3-, 10-, and 20-ml water swallowing in 14 normal subjects. Cricopharyngeus (CP) muscle was investigated during 3- and 10-ml water swallowing in 10 normal subjects. Semisolid and liquid swallowing were compared in eight normal subjects. RESULTS: The total duration of SM-EMG, time necessary for larynx elevation, CP-EMG pause related with upper esophageal sphincter opening and swallowing variability (jitter) all increased significantly with increasing bolus volume. Laryngeal superior relocation time and CP-EMG pause were shorter for semisolid swallowing compared with swallowing the same amount of liquid. CONCLUSION: The duration of SM-EMG activity, laryngeal upward-downward movements, and CP-EMG pause are affected by sensory inputs such as volume and viscosity of the bolus swallowed. The results indicate that sensory input modifies the central swallowing pattern although basic events remain the same in normal human subjects.

Adolescent↗
PubMed1996

Slow motor conduction mainly limited to motor root in amyotrophic lateral sclerosis.

Motor conduction velocity is expected to be normal or nearly normal in amyotrophic lateral sclerosis (ALS). Some studies have suggested that pathology may be present in the proximal axons. Indeed, some investigators have shown a decrease in the proximal conduction velocity in ALS by using motor conduction velocity measurements and H-reflex and F-response recordings, but they could not delineate the precise region of the conduction pathology. In this study, unlike the ones carried out previously, the most proximal segment has been studied in 11 patients with ALS, 13 normal controls, and 5 patients with sequel of poliomyelitis (SPM) by recording sensory and motor spinal root potentials. While no conduction pathology, H-reflex, or F-response abnormalities were found in ALS patients compared to normal subjects, it was shown that conduction velocity decreased in the proximal segment of the lower motor neuron of the ventral root. Despite motor neuron pathology in SPM, there was no proximal motor conduction slowing compared with that in normal subjects.

Adult↗
PubMed1996

Trigemino-cervical reflexes in normal subjects.

Trigemino-cervical reflexes, recorded from the semispinalis capitis muscle (SCM) in the posterior neck, were studied in 35 healthy volunteers, in response to electrical stimulation of the supraorbital trigeminal nerve and glabellar tapping. Simultaneous responses evoked from the ipsilateral orbicularis oculi muscle (OOM) were also recorded i.e. blink reflexes. Electrical stimulation of the supraorbital nerve elicited a reflex response with a latency of about 50 ms from the ipsilateral SCM which was called C3. An early reflex response, which sometimes had two components with latencies of 18 ms and 35 ms, was elicited with glabellar taps. They were called C1 and C2 respectively. When C1 and C2 were elicited with usual glabellar taps, C3 was suppressed. With electrical stimulation, suppression of C1 and C2 was noted, though C3 could easily be obtained. Electrophysiological characteristics of C1 (and C2) were compatible with an oligosynaptic, innocuous reflex, whereas C3 seemed to be multisynaptic and nociceptive in nature. A negative interaction between these two reflexes was observed.

Adult↗
PubMed1996

Sacral cord conduction time of the soleus H-reflex.

The sacral cord conduction time of the soleus H-reflex was investigated in 30 normal adult subjects using three different methods. (1) The posterior tibial nerve was stimulated at the popliteal fossa by graded electric shocks, and the recordings were made from different lumbar epidural intervertebral levels. The afferent action potentials from the dorsal roots and the reflexively evoked efferent action potentials from the ventral roots were recorded. The time interval between the negative peaks of the ventral and dorsal root potentials was used to calculate the approximate sacral cord reflex delay time, which was found to be 1.3 ms. on average. (2) The sacral cord reflex delay time was found to be about 2.0 ms using the conduction time of the afferent, that of the efferent limbs and total reflex time of the soleus H-response. (3) By stimulating the lumbosacral roots at the epidural levels and using the difference between the soleus H and M response latencies, the sacral cord reflex delay was determined to be approximately 2.4 ms. These findings indicated that the soleus H-reflex is exclusively monosynaptic. It is proposed that in humans the synaptic transmission at the sacral cord is approximately 0.4 ms.

Adult↗
PubMed1995

An electrophysiological investigation of deglutition in man.

This article describes a combined electrophysiological and mechanical method used to measure laryngeal movements and related submental EMG activity during swallowing. The mechanical upward and downward movements of the larynx were detected using a piezoelectric sensor while the submental integrated EMG (SM-EMG) was recorded. Measurements were performed in 29 human subjects. The interval between the onsets of the two sensor signal deflections was used as a measure of the time the larynx remained in its superior position during swallowing. In 10 subjects, the cricopharyngeus muscle (CP) of the upper esophageal spinchter showed a continuous tonic EMG activity except during swallowing. All the parameters measured were influenced by the type and volume of the bolus material. The method presented in this study proved its usefulness in the study of the physiology of deglutition as well as in its objective clinical evaluation in patients with dysphagia.

Adult↗
PubMed1990

[Overlay dentures].

Overlay dentures which are accepted as superposition appliances have been presented by three cases in this article. These kind of dentures are dedicated as prosthodontic restorations which are applied to extend maxillary arch horizontally in the cases of maxillary collapse. These restorations also increase the vertical dimension which has been lost and so help to improve the facial contour as well as esthetics of the individual-these dentures classified as removable partial or complete overlay dentures are generally applied in the cases of bilateral or unilateral maxillary collapse which have been caused by trauma or tumor resection.

Denture, Overlay↗
PubMed1990

[Investigation of the castings marginal adaptation using investment expansion methods].

The research in the field of metal casting has recorded a continual progress in dentistry. Particularly, due to the economic problems posed by the use of gold alloys relatively inexpensive metal alloys tend to gain increased popularity. Application of such alloys physically in dentistry and their adaptability to various preparations are being studied. In castings where investment expansion methods are employed, and marginal adaptability of castings are evaluated, the results of variance analysis have indicated little significant difference due to the applied methods. However, the hygroscopic method has proved highly successful in terms of marginal adaptability.

Analysis of Variance↗
PubMed1990

[Comparison of investment expansion methods aspect of porosity].

Currently, the use of non-precious metal alloys in fixed prosthetic restorations has warranted review of the work done sofar using precious metal alloys. One of the parameters exhibiting the success of castings done using non-precious metal alloys is porosity, which is evaluated through such methods as rod forms, waxing heat, to investing and other castability methods. The porosity ratios of cats similarly done employing different investment expansion methods have been evaluated. While there is no statistical difference due to different methods, the hygroscopic expansion method noted successful results.

Dental Alloys↗
PubMed1989

[Use of endodontically treated teeth in removable partial dentures].

In our study, cases where teeth with excessive crown loss served as abutments, where examined in Kennedy Class II modification 1, that have tooth and tissue support on removable partial dentures which were constructed with the same design. Our study aims to examine, how vertically directed forces are transmitted to the supporting tissues by using photoelastic method. Teeth with case post and core appliances were used as abutments for removable partial dentures. Vertical loading procedure following the construction of removable partial dentures with the same design, revealed distribution of force over dentulous and edentulous ridge areas. When a comparison between endodontically treated and sound abutment teeth, was made, we had the conclusion that teeth with excessive crown loss can successfully serve as abutments for partial dentures, because the results of our finding exhibited no significant difference.

Dental Abutments↗