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Biomedical subjects

M Alon

Publications and source records attributed to M Alon.

14 recordsLinked to original sources
PubMed2005

Development of a tissue-engineered composite implant for treating traumatic paraplegia in rats.

This study was designed to assess a new composite implant to induce regeneration of injured spinal cord in paraplegic rats following complete cord transection. Neuronal xenogeneic cells from biopsies of adult nasal olfactory mucosa (NOM) of human origin, or spinal cords of human embryos, were cultured in two consecutive stages: stationary cultures in a viscous semi-solid gel (NVR-N-Gel) and in suspension on positively charged microcarriers (MCs). A tissue-engineered tubular scaffold, containing bundles of parallel nanofibers, was developed. Both the tube and the nanofibers were made of a biodegradable dextran sulphate-gelatin co-precipitate. The suturable scaffold anchored the implant at the site of injury and provided guidance for the regenerating axons. Implants of adult human NOM cells were implanted into eight rats, from which a 4 mm segment of the spinal cord had been completely removed. Another four rats whose spinal cords had also been transected were implanted with a composite implant of cultured human embryonic spinal cord cells. Eight other cord-transected rats served as a control group. Physiological and behavioral analysis, performed 3 months after implantation, revealed partial recovery of function in one or two limbs in three out of eight animals of the NOM implanted group and in all the four rats that were implanted with cultured human embryonic spinal cord cells. Animals of the control group remained completely paralyzed and did not show transmission of stimuli to the brain. The utilization of an innovative composite implant to bridge a gap resulting from the transection and removal of a 4 mm spinal cord segment shows promise, suggesting the feasibility of this approach for partial reconstruction of spinal cord lesions. Such an implant may serve as a vital bridging station in acute and chronic cases of paraplegia.

Animals↗
PubMed2001

Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to examine the recovery of the crushed sciatic nerve of rats after low-power laser irradiation applied to the corresponding segments of the spinal cord. STUDY DESIGN/MATERIALS AND METHODS: After a crush injury to the sciatic nerve in rats, low-power laser irradiation was applied transcutaneously to corresponding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He-Ne laser. The laser treatment was repeated 30 minutes daily for 21 consecutive days. RESULTS: The electrophysiologic activity of the injured nerves (compound muscle action potentials--CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow-up period (P < 0.001). CONCLUSION: This study suggests that low-power laser irradiation applied directly to the spinal cord can improve recovery of the corresponding insured peripheral nerve.

Animals↗
PubMed2001

Double-blind randomized study evaluating regeneration of the rat transected sciatic nerve after suturing and postoperative low-power laser treatment.

This double-blind randomized study evaluated the therapeutic effect of low-power laser irradiation (LPLI) on peripheral nerve regeneration, after complete transection and direct anastomosis of the rat sciatic nerve. After this procedure, 13 of 24 rats received postoperative LPLI, with a wavelength of 780 nm laser, applied transcutaneously, 30 min daily for 21 consecutive days, to corresponding segments of the spinal cord and to the injured sciatic nerve. Positive somatosensory evoked responses were found in 69.2 percent of the irradiated rats (p = 0.019), compared to 18.2 percent of the non-irradiated rats. Immunohistochemical staining in the laser-treated group showed an increased total number of axons (p = 0.026), and better quality of the regeneration process, due to an increased number of large-diameter axons (p = 0.021), compared to the non-irradiated control group. The study suggests that postoperative LPLI enhances the regenerative processes of peripheral nerves after complete transection and anastomosis.

Animals↗
PubMed2001

Pudendal nerve conduction to evaluate organic erectile dysfunction.

OBJECTIVE: This study aimed to evaluate the value of testing pudendal nerve conduction in men with erectile dysfunction. DESIGN: This open prospective study was conducted on 150 men with documented erectile dysfunction of at least 6 mo of duration, all of whom underwent pudendal nerve conduction by the same investigator. RESULTS: Only patients with erectile dysfunction and low back pain (n = 9) showed statistically significant prolonged pathologic pudendal nerve conduction latency of 43.1 msec/div (SD +/- 11.3 msec/div, P < 0.05). There were no correlations between the pudendal nerve conduction latency in patients suffering from erectile dysfunction associated with diabetes mellitus, local trauma, pelvic surgery, or antihypertensive drugs. CONCLUSIONS: Pudendal nerve conduction may contribute valuable information to the evaluation of patients with erectile dysfunction caused by neurologic deficits as manifested by low back pain.

Adult↗
PubMed2000

The value of testing pudendal nerve conduction in evaluating erectile dysfunction in diabetics.

We conducted an open prospective study on the value of testing pudendal nerve conduction (PNC) in 45 diabetic and 32 nondiabetic men with documented erectile dysfunction (ED) of at least six months duration. All subjects underwent PNC by the same investigator using the Medcelec/TECA Sapphire device with calibration parameters of sweep 10 ms/div an amplitude of 200 microV/div. No statistically significant differences was found in the mean bulbocavernosus reflex (BCR) latencies between the nondiabetics (33.6 ms/div +/- 4.1) and the diabetics (37.5 ms/div +/- 9.1) (P > 0.05). Our results show that electrophysiological measurement of the BCR in diabetics is not a useful diagnostic test and emphasize the importance of a multifactorial evaluation of diabetic ED.

Adult↗
PubMed2000

Microsurgical management of old injuries of the peripheral nerve and brachial plexus.

A prospective study was carried out in patients suffering from old peripheral nerve and brachial plexus injuries to attempt to validate that functional improvement was possible after microsurgical management. Fifty patients underwent operative procedures, of whom 35 were peripheral-nerve injury cases, from 1.2 to 50 years after injury, and 15 were brachial-plexus injury cases, from 1.2 to 12 years after injury. The patients were treated by external and interfascicular neurolysis and/or autogenous nerve grafts. In cases of preganglionic nerve injury, neurotization from C3, C4 roots was done for reinnervation of trunks or cords. During external and interfascicular neurolysis in 19 of the 35 peripheral-nerve injuries, significant improvement was found in amplitude (p = 0.0001) and latency (p = 0.01) of compound muscle action potentials (CMAPs) at the end of the surgery, compared to the onset of surgery. Twenty (57 percent) of the 35 showed functional motor improvement up to M4-or M4. Electrophysiologic analysis of amplitude of CMAPs 1 year after surgery showed statistically significant improvement (p = 0.0003). Five (33 percent) of the 15 patients with upper brachial-plexus injuries showed functional motor improvement up to M4-(active movements against gravity and slight resistance) or M4 (active movements against gravity and moderate resistance) after surgery and of these, 11 also had lower brachial-plexus injuries, with four (36 percent) showing antigravity function M3 (active movement against gravity). Statistical analysis of recruitment 1 year after surgery demonstrated the appearance of or significant voluntary muscle activity in 45 percent of the muscles. Intraoperative electrophysiologic findings after external and interfascicular neurolysis confirmed that the viability of nerve tissue is of longer duration than previously considered. This study suggests that the use of microsurgical techniques results in the functional improvement of patients suffering from old injuries of the peripheral nerve and brachial plexus.

Action Potentials↗
PubMed1996

Erectile dysfunction in hypertensive subjects. Assessment of potential determinants.

Hypertension is often cited as a risk factor for erectile dysfunction. To clarify the relation between hypertension and erectile dysfunction, we evaluated 32 consecutive hypertensive and 78 normotensive impotent men with respect to multiple potential determinants and parameters of erectile function, including medical and sexual history, depression, hormonal profile, penile nocturnal tumescence, penile vascular supply, and pudendal nerve conduction. The hypertensive men were older, had higher body mass index, and used more medications than the normotensive men. The groups were not different with respect to the prevalence of smoking and peripheral vascular disease, but the hypertensive men had a marginally higher rate of ischemic heart disease (P = .06). The prevalence of depression, abnormal nocturnal penile tumescence, anomalous pudendal nerve conduction, and impairment in arterial supply as determined by penile brachial index were similar in the two groups. Testosterone and bioavailable testosterone levels were lower in the hypertensive men. After stratification by age and body mass index, hypertensive men younger than 50 years with body mass index less than 30 kg/m2 had significantly lower testosterone levels (12.0 +/- 1.7 versus 21.3 +/- 1.4 nmol/L, P < .02) but not bioavailable testosterone levels (3.9 +/- 0.7 versus 6.4 +/- 0.7 nmol/L, P < .17) than the corresponding normotensive group. Prolactin, follicle-stimulating hormone, and luteinizing hormone levels of the two groups were not significantly different. Contrary to common belief and with the exception of lower circulating testosterone levels, the overall analysis showed little difference between hypertensive and normotensive men with respect to a wide range of classic determinants of erectile function. Direct study of the local vascular erectile apparatus appears necessary for further elucidation of the mechanisms underlying erectile dysfunction in hypertensive men.

Adult↗
PubMed1992

Pupillary responses and blink reflex in myotonic dystrophy.

We have studied pupillary responses to parasympathetic and sympathomimetic agents, pupillary cycle time and the electrophysiology of the blink reflex in 18 patients with myotonic dystrophy. The response of the iris to dilute pilocarpine and phenylephrine did not indicate pharmacologic supersensitivity. Pupillary cycle time was prolonged in nine of the 18 patients. Ipsilateral R1 blink reflex latencies were normal in all cases, and bilateral R2 were normal in 16 of the 18 patients. These results do not support either autonomic or brainstem dysfunction in the majority of patients with myotonic dystrophy. In 50% of the patients the results are compatible with smooth muscle involvement of the iris.

Adult↗
PubMed1990

Postoperative injuries of upper limb nerves.

Three cases of different types of nerve injuries following orthopedic and chest surgery are described. Recovery from these nerve injuries was prolonged and incomplete. By constant awareness of potential nerve damage during operation, it is possible to prevent such injuries.

Angina Pectoris↗
PubMed1988

Bilateral suprascapular nerve entrapment syndrome due to an anomalous transverse scapular ligament.

A rare case is reported of a young woman who suffered from suprascapular nerve entrapment syndrome (SNES) of the right side and two years later developed the same syndrome on the left. At the first operation an anomalous bifid transverse ligament was found and cut. The combination of pressure effect from the congenital defect together with frequent protraction of the shoulder due to her work as a physical education teacher caused triggering of the SNES. The clinical course, electromyographic findings, and differential diagnosis are reported. Cutting of the anomalous ligament on both sides brought relief from pain, weakness, and atrophy of the shoulder muscles, enabling the patient to return to work.

Adult↗