Biomedical subjects

N Yildiz

Publications and source records attributed to N Yildiz.

7 recordsLinked to original sources

PubMed2005

Central and peripheral motor conduction to cremasteric muscle.

The few electrophysiologic studies of the cremasteric muscle (CM) have mainly been restricted to the cremaster reflex with no reference to central and peripheral nerve conduction to the muscle, probably for technical reasons.Twenty-six normal adult male volunteers were studied by transcranial magnetic cortical stimulation (TMS) and stimulation of thoracolumbar roots. The genitofemoral nerve (GFN) was stimulated electrically at the anterior superior iliac spine and a needle electrode was inserted into the CM for conduction studies. The motor latency to the CM from the cortical TMS ranged from 20 to 33 ms among the subjects (25.8 +/- 2.9 ms, mean +/- SD). Magnetic stimulation of the lumbar roots produced a motor response of the CM within 9.6 +/- 1.9 ms (range, 6-15). The central motor conduction time to the CM was 16.5 +/- 2.8 ms (range, 10-21). Stimulation of the GFN produced a compound muscle action potential with a mean value of 6.4 +/- 1.8 (range, 4-10) ms in 23 of the 26 cases. Thus, central motor nerve fibers to the CM motor neurons exist, and there may be a representation area for the CM in the cerebral cortex. The GFN motor conduction time to the CM may have clinical utility, such as in the evaluation of the groin pain due to surgical procedures in the lower abdomen.

Adult↗

PubMed2004

Changes in the perioral muscle responses to cortical TMS induced by decrease of sensory input and electrical stimulation to lower facial region.

OBJECTIVE: To determine the changes in the motor cortex due to repetitive electrical stimulation and cutaneous anesthesia in lower facial region. METHODS: A total of 11 subjects participated in the study of repetitive electrical stimulation, and 10 other subjects in the study of lower facial anesthesia. Facial nerve root and face associated cortical MEPs by transcranial magnetic stimulation (eight-shaped coil) were recorded from perioral muscles pre- and post- electrical stimulation and lower facial anesthesia. Cheek near to the corner of the mouth was transcutaneously stimulated by bipolar surface electrode giving repetitive electrical shocks at 5 Hz. Five percent lidocain/prilocain local anesthetic cream was applied to left or right lip-cheek region. RESULTS: There was no significant change in perioral MEP responses after 10-30 min of 5 Hz electrical stimulation. We found a significant increase of amplitude in cortical MEP recordings during lower facial anesthesia especially in cases of cortical magnetic stimulations ipsilateral and contralateral to the anaesthetized side and in perioral recordings contralateral to the anaesthetized side. CONCLUSIONS: The present study demonstrates that topical anesthesia to the lower facial region leads to cortical modulation and fast plastic changes in both hemispheres that are directed to the normal side.

Adult↗

PubMed2003

Optimum trace count necessary for jitter calculation in single-fiber electromyography.

OBJECTIVE: To clarify the optimum trace count for jitter calculation. MATERIALS AND METHODS: Single-fiber electromyography was performed during voluntary contraction (VC-SFEMG) of extensor digitorum muscle in six healthy and five myasthenic subjects. Twenty single-fiber action potential (SFAP) pairs were recorded from each subject. For each pair, 100 consecutive traces were recorded and stored for off-line analysis. Ten different jitters were calculated in 10 consecutive steps for each SFAP pair by increasing the number of traces included to analysis (from 10 to 100). The jitter calculated in each step was compared with that calculated from 100 traces. RESULTS: Sixty was the optimum number of trace count for both myasthenics and normal controls. Using less than 60 traces for jitter calculation revealed lower values. CONCLUSION: Jitter calculation should be performed from at least 60 traces in VC-SFEMG. Less numbers yield lower jitter and may cause diagnostic error.

Action Potentials↗

PubMed2000

Concentric needle electrode for neuromuscular jitter analysis.

We used a concentric needle electrode (CNE) with 2 kHZ low-cut filter and a single fiber electrode (SFE) in the same subjects for neuromuscular jitter measurement in the extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles. At the same session, 20 jitter values were obtained from each subject with each electrode. For EDC (during voluntary contraction), mean jitter values with SFE and CNE were 23.4 +/- 8 micros and 23.3 +/- 8 micros in 10 normals; and 56.8 +/- 28 micros and 57.4 +/- 33 micros in 10 myasthenics. For OOc (during electrical stimulation), mean jitter values with SFE and CNE were 17.9 +/- 5 micros and 16.3 +/- 4 micros in 11 normal subjects, and 41.2 +/- 29 micros and 36.7 +/- 27 micros in 10 myasthenics. For both muscles, the numbers of individual abnormal jitter values with SFE and CNE were highly comparable. Both needles labeled the same patients as having "normal" or "abnormal" neuromuscular transmission. CNE may be an alternative to SFE in neuromuscular jitter analysis.

Adolescent↗

PubMed2000

Effects of growth hormone replacement therapy on lipids, lipoproteins and apolipoproteins: is the increased apolipoprotein A-1/B ratio the only benefit?

BACKGROUND: The aim of the present study was to investigate the controversial role of growth hormone (GH) therapy in lipid regulation. METHODS: We studied serum levels of cholesterol and subgroups, triglyceride and apolipoprotein A-1 and B in 41 GH-deficient children (with subgroups of untreated and short- and long-term treated subjects) and 20 healthy controls. RESULTS: Cholesterol and low-density lipoprotein cholesterol levels (in mmol/L) were found to be 4.92 +/- 1.34 and 3.02 +/- 1.58 in untreated, 4.15 +/- 0.72 and 2.46 +/- 0.65 in short-term (3 month) treated, 4.93 +/- 1.39 and 3.15 +/- 1.38 in long-term (> 1 year) treated and 4.11 +/- 0.5 and 2.0 +/- 0.74 in control subjects, respectively. The apolipoprotein A-1:B ratio was 1.98 +/- 0.5 in long-term treated and 1.6 +/- 0.6 in control subjects. CONCLUSIONS: The improvement of lipid composition with short-term GH therapy is temporary, but the increase in apo A-1:B is not and seems to be the particular benefit of this therapy.

Adolescent↗

PubMed1996

Nuclear protein binding and functional activity of a variant insulin gene found in non-insulin-dependent diabetes mellitus.

In a subset of patients with non-insulin-dependent diabetes mellitus an 8-base pair (bp) repeat was found from -322 to -315 in the 5'-flanking region of the insulin gene. This 8-bp repeat is inserted into a sequence that is highly homologous to a sequence motif, called PISCES (pancreatic islet cell-specific enhancer sequences), found within cell-specific enhancer elements of the rat insulin I (Ins-E1, from -332 to -285), rat glucagon (Glu-G3) and rat somatostatin (SMS-UE) genes. The PISCES motif confers pancreatic islet-specific activity and is recognized by an islet-specific transcription factor (PISCES-BP). The consequences on functional activity and on protein binding of the 8-bp repeat sequence in the human insulin promoter was investigated. When fused to a reporter gene and transiently transfected into an insulin-producing islet cell line, the 8-bp repeat decreased basal transcriptional activity of the human insulin promoter (from -366 to +42) whereas the induction of promoter activity by cAMP was unaffected. The isolated rat Ins-E1 element was sufficient to confer basal transcriptional activity to a minimal promoter; the corresponding fragments of the normal and variant human insulin genes (from -329 to -288), however, were not. Using nuclear extracts in an electrophoretic mobility shift assay, it was found that PISCES-BP recognizes rat Ins-E1, but PISCES-BP binding to the corresponding normal and variant human insulin promoter fragments was not detectable and weak, respectively. However, a nuclear protein was found that binds to the variant but not normal human sequence. These data suggest that the 8-bp repeat in the variant human insulin promoter found in patients with non-insulin-dependent diabetes mellitus allows the binding of a nuclear protein that interferes with promoter function.

Animals↗

PubMed1994

[DIDMOAD syndrome].

The DIDMOAD or so called Wolfram syndrome is a hereditary disease with autosomal-recessive transmission showing 4 main features: diabetes mellitus, diabetes insipidus, nervus opticus atrophia and deafness. Beside this it shows multiple organ involvement. Our 38-year old male patient, showing all above mentioned features except deafness had urinary tract involvement and neurological symptoms. EEG, cerebral MRI, tests with evoked potentials and HLA-typing were performed to discuss the aetiopathogenetic background in our patient. Almost all symptoms of the Wolfram syndrome can be mixed up with complications of diabetes mellitus, which is usually the first symptom of the Wolfram syndrome. Because of this, wrong diagnosis is not rare. Hence in differential diagnosis in any diabetes mellitus type I patient, the possibility of the Wolfram syndrome should be discussed.

Adult↗