Biomedical subjects

M Hassouna

Publications and source records attributed to M Hassouna.

At least 37 records · Page 2Linked to original sources

PubMed1992

Role of electric stimulation in bladder evacuation following spinal cord transection.

Neural stimulation is potentially a valuable therapeutic tool in the treatment of neurogenic bladder with detrusor areflexia. We studied 20 dogs in different groups, up to eight months, and compared the effect of electric stimulation with intermittent catheterization, specially during spinal shock phase. We found that early stimulation hastened the return of detrusor activity. When stimulation was delayed, the bladder could still regain its activity, and when the pace-maker was turned off, the detrusor activity was gradually decreased. Neurostimulation can completely empty bladder up to eight months. The lowest A.Ch. content in detrusor muscle was found in intermittent catheterization group and in this group the detrusor strips showed marked supersensitivity to urecholine stimulation than the bladders managed by electric stimulation. Also, we found that electric stimulation reduced the complications caused by intermittent catheterization and protected kidney function.

Animals↗

PubMed1991

Digital subtraction cavernosography: method to detect venous leakage.

Cavernosography has become an important diagnostic test for detecting venous leakage as a cause of vasculogenic impotence. Digital subtraction cavernosography (DSC) was carried out on 21 patients with a history of venous leakage resulting in impotence. The DSC technique was compared to conventional cineradiography. Major venous leaks were easily identified in 16 patients. DSC was able to detect minor leaks missed by cineradiography in 2 patients. DSC seems to be a reliable technique that is easy to perform. It should be done in conjunction with pharmacologically induced erection.

Angiography, Digital Subtraction↗

PubMed1989

Keratinophilic fungi on sheep hairs from the West Bank of Jordan.

The mycoflora of the hair in 285 sheep from the West Bank of Jordan was analysed and the frequency of occurrence and the relative importance value for different fungal species found were calculated. Ninety six species which belong to 36 genera were isolated. Forty one of these species were either well-known agents of animal and human mycoses (Trichophyton verrucosum, T. mentagrophytes, Microsporum nanum, M. canis, and others), or have been isolated from human and animal lesions (Arthroderma cuniculi, A. curreyi, Chrysosporium tropicum, Acremonium kiliense, Aphanoascus fulvuscens, Aspergillus versicolor, Paecilomyces lilacinus, Scopulariopsis brevicaulis, and others). These pathogenic fungi comprised 75.4% of all fungi recovered from the hair of sheep. This animal seems to represent an adequate reservoir for several dermatophytes and several potentially pathogenic fungi.

Animals↗

PubMed1989

Priapism: an avoidable complication of pharmacologically induced erection.

Priapism is an alarming complication during treatment of erectile dysfunction with vasoactive drugs, particularly papaverine alone or in combination with phentolamine mesylate. An investigational protocol was designed to identify patients who are more susceptible to priapism after intracavernous injection of papaverine alone or with phentolamine. The protocol was applied in 331 men with impotence of various etiology. The association of a positive response to visual sexual stimulation and penile brachial index of more than 0.8 represented a higher risk for post-injection priapism. We were able to reduce the incidence of this compliance to 1% in the last 101 patients.

Humans↗

PubMed1989

The effect of early bladder stimulation on spinal shock: a preliminary report.

The period of spinal shock which frequently follows spinal cord injury is associated with bladder areflexia and urinary retention. We studied the effect of early bladder electric stimulation on detrusor activity during the spinal shock phase in the dog. The animals had a spinal cord section at T10 vertebra and their bladder management was assigned to one of the three following groups: intermittent catheterization, indwelling catheterization and electric bladder stimulation. The parameters for evaluating each treatment included: blood chemistry, radiographic and urodynamic tests. The salient feature was the early return of detrusor activity in the group of animals treated by early electric stimulation of the bladder.

Animals↗

PubMed1988

Keratinophilic fungi on the hair of goats from the West Bank of Jordan.

The mycoflora of the hair in 178 goats from the West Bank of Jordan was analysed and the frequency of occurrence and the relative importance value for the different keratinophilic fungi found were calculated. One hundred and seven species which belong to 38 genera were isolated. Thirty six of these species were either well recognised agents of mycoses (Trichophyton mentagrophytes, T. verrucosum, and M. nanum), or have been frequently isolated from human and animal lesions (Arthroderma spp., Acremonium kiliense, Alternaria alternata, Aspergillus flavus, Cladosporium carionii, and several other species). These potentially pathogenic fungal species comprised 66.9% of all keratinophilic fungi found on the hair of goats. The role of this animal as a reservoir for dermatophytes and other potentially pathogenic fungi is discussed.

Animals↗

PubMed1988

Keratinophilic fungi on the hair of cows, donkeys, rabbits, cats, and dogs from the West Bank of Jordan.

The mycoflora of hair of 111 cows, donkeys, rabbits, cats, and dogs were analysed and the frequency of occurrence and the relative importance value of the different fungal species isolated were calculated. Total numbers of species 56, 45, 48, 23, and 11 were recovered from cows, donkeys, rabbits, cats, and dogs respectively. The majority of the keratinophilic fungi isolated were either well-known mycotic agents or have been recovered from various animal and human lesions. These comprised 87.8%, 66.7%, 61.4%, 59.3%, and 55.2% of the hair mycoflora in cats, dogs, rabbits, cows, and donkeys respectively. Seven species of dermatophytes were isolated: Trichophyton mentagrophytes, T. verrucosum, Microsporum gypseum, M. nanum, T. ajelloi, and M. canis. Cats harboured the largest number of dermatophytes (5 species), followed by cows (4 spp), rabbits (3 spp), and donkeys and dogs (1 sp). The role of these animals in the persistence and transmission of pathogenic fungi is discussed.

Animals↗

PubMed1987

Effects of verapamil and sodium nitroprusside on acetylcholine-induced contraction of the rabbit detrusor muscle.

Effects of extracellular and intracellular Ca2+ on acetylcholine-induced contraction of the bladder detrusor muscle were studied in vitro, utilizing two types of Ca2+ antagonists of different mechanisms of action; verapamil and sodium nitroprusside (NP). Acetylcholine (10(-8) to 10(-2) M) caused dose-dependent contractions of the detrusor muscle strips. Pretreatment of the strips with verapamil (10(-7), 10(-6) M) significantly inhibited the acetylcholine-induced contraction in a dose-dependent manner, whereas NP (10(-7) to 10(-5) M) failed so suppress the contraction. The contraction of the strips once elicited by acetylcholine (10(-6) M) could be completely relaxed by verapamil (10(-5) M) addition, but only incompletely by NP (10(-5), 10(-4) M). In Ca2+-free solution containing 0.01 mM EGTA, replenishment of Ca2+ (2.5 mM) to the medium caused contractions of the strips. Addition of acetylcholine (10(-6) M) to the medium enhanced the Ca2+-induced contraction, which was significantly inhibited by pretreatment with verapamil (10(-6) M), but not affected by NP (10(-6) M). In Ca2+-free medium containing 0.1 mM EGTA, acetylcholine caused a slight degree of tension increase of the strips in a dose-dependent fashion, at higher concentrations exceeding 10(-6) M. These results suggest that the detrusor muscle contraction induced by acetylcholine is mostly dependent of extracellular Ca2+ influx both in its initiation and maintenance. It is also supposed, however, that intracellular Ca2+ fractions will partly participate in the acetylcholine-induced contraction and possibly in its maintenance.

Acetylcholine↗

PubMed1986

Urethral stricture following cardiovascular surgery: role of urethral ischemia.

The incidence of urethral stricture has been surprisingly high following cardiovascular surgery in the last few years. We conducted a prospective study on 68 male patients undergoing cardiovascular surgery to determine the main factor(s) responsible for the development of urethral stricture. The penile-brachial pressure index was checked by strain gauge plethysmography. We found that urethral strictures developed in 15 patients (22 per cent) within an average of 3 months after cardiovascular surgery. Of these patients 13 had a penile-brachial index of 0.6 or less and complained of erectile impotence. A latex type of catheter was used in 11 and a silicone catheter in 4 of these 15 patients for urinary drainage. We conclude that urethral ischemia has an important role in the development of stricture, particularly when a latex urethral catheter is used for drainage. We recommend that a vascular penile study should be done in patients with erectile impotence undergoing an open heart operation, and that serious consideration should be given to the use of a cystocatheter diversion the night before the operation in those with a penile-brachial index less than 0.6. We strongly recommend the use of a silicone catheter in all other patients undergoing open heart surgery with hypothermia.

Adult↗

PubMed1986

The mode of action of prostaglandin E2, F2 alpha and prostacyclin on vesicourethral smooth muscle.

Interactions of prostaglandin E2 (PGE2), F2 alpha (PGF2 alpha) and prostacyclin (PGI2) with Ca2+ on the isometric contraction of rabbit detrusor muscle strips were studied using two types of Ca2+ antagonists of different mechanisms of action: verapamil and sodium nitroprusside (NP). The effects of PGI2 on vesicourethral smooth muscle and their relationship with cholinergic, adrenergic receptors and nervous activity were also investigated. PGE2 and F2 alpha (3 X 10(-8) to 3 X 10(-5) M) caused dose-dependent contraction of the strips. Pretreatment of the strips with verapamil (10(-7) to 10(-5)M) significantly inhibited PGs-induced contraction in a dose-dependent manner, whereas NP(10(-7) to 10(-5)M) failed to suppress the contraction. Relaxation of the preparations once contracted by PGE2 and F2 alpha (3 X 10(-6)M) was induced completely by addition of verapamil (10(-5)M), and incompletely by NP(10(-5) to 10(-3)M). Washing of the strips with Ca2+-free solution containing 0.01 mM EGTA completely eliminated spontaneous activity and diminished basal tension, but replenishment of Ca2+ (0.5 to 10 mM) to the medium caused dose-related contraction and spontaneous activity of the strips. Addition of PGE2 and F2 alpha to the Ca2+-free medium enhanced Ca2+-induced contraction and spontaneous activity during Ca2+ replenishment, which were significantly inhibited by pretreatment with verapamil (10(-7) to 10(-5)M) in a dose-dependent manner, but not affected by NP (10(-7) to 10(-5)M). In Ca2+-free medium containing 0.1 mM EGTA, PGE2 and F2 alpha caused a slight degree of tension increase of the strips dose-dependently at the higher concentration exceeding 3 X 10(-6)M. PGI2 (10(-9) to 3 X 10(-4)M) caused dose-dependent contraction of the strips from the bladder body, base and the urethra. The contractile action of PGI2 was greatest on the bladder body, less on the base and minimal on the urethra. The effect of PGI2 was less potent than those of PGE2 and F2 alpha. The PGI2-induced contraction was slow in onset, short lasting, and not affected by pretreatment with phentolamine, propranolol, atropine, hexamethonium, hemicholinium-3 and tetrodotoxin. The interactions of PGI2 with Ca2+ were similar to those of PGE2 and F2 alpha.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1986

Intravesical instillation of a calcium entry blocker and its effects on detrusor contractility: in vitro and vivo experiments.

The effects of intravesical instillation of a Ca2+ entry blocker (verapamil) on the contractility of the bladder detrusor muscle of the rabbit were investigated in vitro and in vivo. In in vitro experiments, using whole bladder preparations, spontaneous contractile activity and contraction induced by direct electric stimulation or acetylcholine were monitored. Both activities were inhibited in a time-dependent manner after the intravesical instillation of 7.5 mg. verapamil. The amplitude of spontaneous contraction 90 minutes after the instillation, was reduced to 10 per cent of control (before the instillation), and the response to electric stimulation and acetylcholine were inhibited to 16 per cent and 38 per cent of controls respectively. The detrusor contractility was still inhibited two hours after the removal of verapamil from the bladder. This inhibition of the detrusor contractility after removal of verapamil was completely reversed by adding four mM Ca2+ intravesically. During in vivo experiments, the changes of intravesical pressure elicited by pelvic nerve stimulation and the systemic arterial pressure were monitored. Sixty minutes after the intravesical instillation of 10 mg. verapamil, the rise of the intravesical pressure following the pelvic nerve stimulation was inhibited to 18 per cent of control, while the systemic arterial pressure was not affected. It is suggested that the intravesical instillation of verapamil can inhibit detrusor contractility without affecting cardiovascular status.

Acetylcholine↗

PubMed1986

Role of calcium ion antagonists of the bladder detrusor muscle: in vitro and in vivo study.

Calcium (Ca2+) ions play an important role in the contractility of the detrusor. Most of the neurotransmitters and modulators act on the detrusor through altering the final intracellular concentration of Ca2+. We studied three commonly used Ca2+ antagonists on their effect of detrusor contractility in vitro: verapamil, nifedipine and segontin. All three inhibited the detrusor-induced contraction in a dose-dependent fashion. Verapamil showed noncompetitive inhibition. Segontin showed a competitive inhibition on both phasic and tonic contractions of the detrusor strips. Nifedipine selectively inhibited the phasic contraction noncompetitively but competitively suppressed the tonic contraction. The in vivo application of verapamil on the bladder of rabbits with multiple-sclerosis-like disease showed a significant increase in bladder capacity. The study shows the possibility of the potential use of Ca2+-antagonist to suppress the problem of bladder instability.

Animals↗

PubMed1984

Vesicourethral motility following acute spinal cord transection in the cat.

The cause of urinary retention during the phase of spinal shock is still uncertain. In the cat with intact spinal cord, reflex voiding shows a coordination between the longitudinal and circular urethral muscles, the detrusor and the periurethral striated muscles. After transection of the spinal cord in cervical and/or thoracic segments, 26 of 28 cats failed to void. An incoordination between longitudinal, circular, detrusor and periurethral striated muscles was noticed simulating a urethro-urethral and urethrovesical dyssynergia. The 2 cats that voided 6 hours after the cord section showed a return of synergism between longitudinal, circular, detrusor and periurethral striated muscles. The conventional pharmacologic manipulation used during the early period following spinal cord transection, bethanechol chloride and phentolamine, failed to achieve proper bladder emptying because it did not correct the dyssynergic pattern.

Animals↗

PubMed1984

Role of urethral ischemia in the development of urethral strictures after cardiovascular surgery: a preliminary report.

A high incidence of urethral stricture was noted following cardiovascular surgery. In an attempt to elucidate factors predisposing to the occurrence of urethral stricture, we studied the penile blood flow in 7 patients presenting with strictures after cardiovascular surgery. Of these patients 5 had penile-brachial pressure indexes less than 0.5 and 6 had weak or absent erections. Of 14 patients studied prospectively by penile blood flow 2 had a low penile-brachial pressure index and suffered urethral strictures 6 weeks after cardiovascular surgery. This finding suggests that urethral ischemia could be a predisposing factor for the development of urethral strictures after cardiovascular surgery.

Adult↗

PubMed1983

Visual internal urethrotomy in management or urethral strictures.

Visual internal urethrotomy was used in the treatment of urethral strictures in 103 patients. The procedure was performed mostly under local anesthesia. Urethral catheter for forty-eight hours or urethral splinting for two weeks was used as complementary treatment in some cases. We obtained an overall success rate of 95.1 per cent.

Anesthesia, Local↗

PubMed1983

Bladder and urethral dynamics in multiple sclerosis-like animal model.

Multiple sclerosis-like disease was induced in 18 rabbits by immunization with guinea pig spinal cord. The urodynamic studies conducted in the immunized rabbits showed a significantly lower maximal urethral pressure and a lower bladder capacity than those in the control group. We compared the urodynamic, clinical and histopathological parameters in the immunized rabbits. We conclude that the rabbit is an acceptable model for studying the bladder and urethral dynamics during various phases of experimental allergic encephalomyelitis (multiple sclerosis-like disease).

Anesthetics↗

PubMed1983

Response of urethral smooth muscles to pharmacological agents. II. Noncholinergic, nonadrenergic agonists and antagonists.

We studied the effects of a variety of noncholinergic, nonadrenergic agents on the smooth muscles of the cat urethra. Prostaglandin F2 alpha contracted both urethral muscle layers to a similar extent. Prostaglandin E2 contracted the longitudinal and relaxed the circular muscle layers. The effects of the prostaglandins seem to be directly myogenic since cholinergic and adrenergic blockers and tetrodotoxin did not affect them. Bradykinin and substance P contracted both urethral muscle layers. Other tested agonists (neurotensin, vasoactive intestinal peptide, cyclic 3,5 adenosine monophosphate, adenosine diphosphate sodium, cyclic 3,5 guanosine monophosphate sodium, bombesin) had no effect on the cat urethral smooth muscles.

Animals↗

PubMed1983

Response of the urethral smooth muscles to pharmacological agents. I. Cholinergic and adrenergic agonists and antagonists.

We studied the effects of cholinergic and adrenergic agents on the 2 muscle layers of the proximal urethra of the cat. Strips were challenged with bethanechol chloride, phenylephrine and isoproterenol. Bethanechol chloride caused contraction of the longitudinally oriented strips; the circularly oriented strips revealed either minimal or no response to the same doses. The difference between the response of the 2 layers was highly significant (p less than 0.001). Phenylephrine stimulated both layers with a nonsignificant difference. Isoproterenol caused relaxation of both layers with a significant action on the circularly oriented fibers (p less than 0.05). It could be concluded that the cholinergic effect which is predominant on the longitudinal fibers is important for voiding by shortening the proximal urethra. alpha-adrenergic innervation of the bladder neck has a function during ejaculation: closure of the bladder outlet by the circular fibers. beta-adrenergic agonists decrease the urethral pressure probably by relaxing both layers with a dominant effect on the circular layer.

Animals↗