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Biomedical subjects

A Elbadawi

Publications and source records attributed to A Elbadawi.

At least 19 recordsLinked to original sources
PubMed1995

"Cercariform" cells: a clue to the cytodiagnosis of transitional cell origin of metastatic neoplasms?

The "cercariform" cell is described as a distinct cytomorphologic clue that may be helpful in the diagnosis of metastatic transitional cell neoplasms, particularly low grade. This cell has a nucleated globular body and a cytoplasmic process with a nontapering, flattened, bulbous or fishtail-like end. The cercariform cell corresponds to intermediate cells in histologic and ultrastructural preparations of normal urothelium. The cercariform appearance is the result of pseudostratification of both normal and low-grade neoplastic urothelium. The unique features of cercariform cells make them readily distinguishable from neoplastic squamous cells as well as spindle cells of mesenchymal origin.

Adult↗
PubMed1995

Pathology and pathophysiology of detrusor in incontinence.

Incontinence is a common urologic problem, especially in the elderly. Ultrastructural study of the detrusor is crucial for the understanding of its normal and abnormal functional behavior. Prospective, correlative, ultrastructural studies in the elderly revealed distinctive patterns of the overactive (unstable) detrusor, whether occurring alone or together with impaired detrusor contractility or bladder outlet obstruction. These patterns provide better insight into pathophysiology of the unstable bladder, and a great potential in diagnosis of detrusor dysfunction in general.

Aging↗
PubMed1992

Comparative autonomic responses of the cat and rabbit bladder and urethra.

The cat and the rabbit have both been utilized extensively in the study of lower urinary tract function. Previous studies have demonstrated that although both the cat and rabbit bladder are approximately the same weight, the in-vitro cat bladder can generate over 6 times the intravesical pressure of the rabbit bladder. The current study was designed to compare the ability of the isolated bladder to generate pressure with the pressures required to maintain flow through the isolated urethra for both the cat and the rabbit. The results can be summarized as follows. 1) The cat bladder is visibly much thicker than the rabbit bladder, and in vitro cystometry demonstrates that it is far less compliant than the rabbit bladder. 2) Over 20 cm.H2O pressure is required to begin flow through the isolated cat urethra preparation, whereas 5 cm.H2O begins flow through the rabbit urethra. 3) Increasing the flow rate (up to 7-fold) through both the isolated cat and rabbit urethra increases intraurethral pressure only slightly. 4) Both the isolated cat and rabbit urethra respond strongly to field stimulation and alpha-adrenergic stimulation (relative to the opening pressure required to begin flow), but not to cholinergic stimulation. 5) Field stimulation following pre-stimulation by methoxamine induces a strong relaxation of the pre-stimulated cat urethra, but an additive contraction in the pre-stimulated rabbit urethra. These studies demonstrate that in order for the cat to empty its bladder, it must generate a comparatively high intravesical pressure, whereas the rabbit is required to generate a relatively low intravesical pressure.

Animals↗
PubMed1992

Studies on experimental bladder outlet obstruction in the cat: long-term functional effects.

Experimental bladder outlet obstruction in cats induces a significant increase in the in vivo leakage pressure. The effects of obstruction on the detrusor function were analyzed, using control, 3, 6 and 12 month obstructed cats. The in vivo leakage pressures were substantially increased in all obstructed groups. From a previous study on the short-term effects of obstruction in the cat; although there was an immediate increase in pressure, there were no significant differences between control bladders and two week obstructed bladders in: bladder weight, peak pressure response to field stimulation and bethanechol, and emptying of the in vitro whole bladder model. In this current study, although there was no direct relationship between duration of obstruction and severity of the impaired pharmacological response of the isolated whole bladder, there was a direct relationship between the magnitude of the increase in bladder weight, leakage pressure, and impaired functional response of the in vitro whole bladder. In this regard the cats were separated into four groups: controls and shams (average bladder weight 2.95 gm.), obstructed group 1 with bladder weights less than 6.0 gm. obstructed group 2 with bladder weights between 6 and 10 gm., and obstructed group 3 with bladder weights greater than 10 gm. The results can be summarized as follows: A) In vivo leakage pressures were significantly increased in all obstructed groups, and progressively higher in proportion to the bladder weights. B) Bladder capacity significantly increased in all, being greatest in obstructed group 3. C) The magnitude of the response to field stimulation of obstructed groups 1 and 2 were significantly greater than the response of control bladders at virtually all frequencies. The frequency response curve of obstructed group 3 was similar to control. D) The ability of the bladder to empty in response to field stimulation was significantly reduced in all obstructed groups. The magnitude of the decrease was proportional to the increase in bladder weight. E) There were no differences between control and obstructed bladders in the pressure response to bethanechol or KCl; the ability of both bethanechol and KCl to empty the bladder was reduced in the obstructed groups. In general, the presence of bladder enlargement was accompanied by significant alterations in the ability of the in vitro bladder to empty in response to field stimulation, bethanechol, and KCl.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Creation of a feline model of obstructive uropathy.

The aim of this project was to create a reproducible, quantifiable feline model of obstructive uropathy. Seventy-three adult female cats of comparable age were evaluated to obtain the normal control urodynamic data base. Twenty-four cats had a silastic cuff installed around the urethra to induce bladder outlet obstruction, and eight underwent a sham operation. Repeated urodynamic evaluations were performed at predetermined postoperative intervals. The obstructed and normal cats inhibited detrusor contractility by reflex striated urethral sphincter activity. Measurements of voiding pressure to verify the presence, and to assess the degree of induced outlet obstruction, required paralysis of the sphincter by curare. Following cuff implantation, voiding pressure increased from a mean normal of 17.2 cm./H2O to 31.6 to 42.5 cm./H2O in animals designated as moderately obstructed, and to 101.7-125.0 cm./H2O in animals designated as severely obstructed. 84.6% of the high pressure bladders developed vesicoureteral reflux. Analysis of resting, low bladder volume, urethral pressure profile (UPP) data and voiding pressures indicate a compensatory sphincteric response to filling in non-curarized animals, and a lack of that response in curarized animals. It appears that implantation of a silastic cuff to prevent full opening of the urethra during voiding, without actually compressing it, is a reasonable model of obstructive uropathy. The observation that the relationship between striated urethral sphincter activity and inhibition of detrusor contractility is influenced by administration of curare was unexpected, and may have clinical implications.

Animals↗
PubMed1991

Effects of parasympathetic decentralization on some nerve-mediated functions in the feline urinary bladder.

Isolated detrusor muscle from control cats and cats parasympathetically decentralized for 3 and 10 weeks responded to electrical field stimulation by tetrodotoxin-sensitive, frequency-dependent contractions. There were no significant differences in the frequencies producing 50% response. However, the amplitude of the scopolamine-resistant contraction was distinctly lower in decentralized bladder preparations than in controls. Decentralized detrusor muscle (10 weeks) showed no increased response to alpha-adrenoceptor stimulation (phenylephrine, clonidine, noradrenaline), but the sensitivity to carbachol (at 3 and 10 weeks) was significantly decreased compared with controls. The release of [3H]noradrenaline was decreased by carbachol 10(-7) to 10(-5) M both in controls and in decentralized (10 weeks) detrusor muscle, the decrease being significantly more pronounced in the decentralized group at carbachol concentrations of 10(-7) and 10(-6) M. There were no differences between controls and decentralized bladders of muscarinic receptor concentration, but decentralization significantly reduced the affinity for the radioligand used to label the receptors. Thus, the main changes caused by parasympathetic decentralization of the feline bladder seem to be a reduced post-junctional, but an increased prejunctional response to muscarinic receptor stimulation.

Animals↗
PubMed1990

Comparative physiology and pharmacology of the cat and rabbit urinary bladder.

The cat and the rabbit are two of the most popular models for the study of lower urinary bladder function. The cat has been used extensively for in-vivo studies of spinal and supra-spinal micturition reflexes. In contrast, the rabbit has been used extensively for the in-vitro study of bladder function. In order to determine if the results obtained using one species can be applied to another, we have compared the in-vitro physiology and pharmacology of the cat and rabbit bladder using isolated strips and whole bladder preparations. The results can be summarized as follows: 1) The cat displays significant spontaneous activity during in-vitro cystometry, but the rabbit shows no such activity (whole bladder studies). 2) Although the bladder weights of the cat and rabbit are similar, the rabbit bladder has a capacity three times that of the cat. 3) The maximal response to field stimulation was obtained at one gram of passive tension for the rabbit isolated strips, whereas five grams of passive tension was required for the cat strips. 4) Atropine inhibited the response of isolated strips of cat bladder to field stimulation by approximately 13% whereas the response of rabbit bladder strips was inhibited by approximately 45%. 5) The magnitude of the response of rabbit bladder strips to ATP was similar to the response to field stimulation in the presence of atropine; the response of cat bladder strips to ATP was only 20% of the response of that of the rabbit bladder strips, and approximately 10% of the response of the cat strips to field stimulation in the presence of atropine. 6) Field stimulation produced a 10fold greater rise in intravesical pressure in the cat isolated bladder than in the isolated rabbit bladder; in response to bethanechol, the cat bladder generated a 6-fold greater response than the rabbit bladder. It is clear that the in-vitro pharmacological responses of the cat urinary bladder are qualitatively and quantitatively different from that of the rabbit bladder.

Adenosine Triphosphate↗
PubMed1990

Short term functional effects of bladder outlet obstruction in the cat.

Experimental bladder outlet obstruction in cats was produced by surgical placement of a silastic cuff around the urethra. Two sizes of cuff were used to produce either moderate or severe obstruction. The following is a summary of the short-term effects on bladder function. Obstruction induced a significant increase in the in vivo voiding pressure, in proportion to severity of the obstruction. There were no significant differences between control and obstructed cats in bladder mass, response of the isolated whole bladder to field stimulation or bethanechol, response of isolated bladder strips to field stimulation, bethanechol and ATP, or muscarinic receptor density in the bladder body. Although there were no differences in bladder mass between control and obstructed bladders, the hydroxyproline concentration of the severely obstructed bladders was significantly reduced. Creatine phosphate concentration was also significantly reduced in obstructed bladders. Although all whole cat bladder preparations displayed spontaneous contractile activity during in vitro cystometry, the obstructed bladders had a greater amplitude and frequency of spontaneous contractions with a lower volume threshold. In addition, the obstructed bladders had a greater tetrodotoxin-resistant contractile response to field stimulation. These results suggest that the obstructed cat bladder can compensate for increased outlet resistance without induction of bladder hypertrophy or significant functional changes, as seen in both rat and rabbit.

Adenosine Triphosphate↗
PubMed1987

Interaction between adrenergic and cholinergic nerve terminals in the urinary bladder of rabbit, cat and man.

The influence of muscarinic receptor stimulation (carbachol) and blockade (scopolamine) on the release of 3H-labelled noradrenaline from adrenergic neurons was investigated in isolated detrusor preparations from rabbit, cat and man. A significant influence on the release of 3H from adrenergic nerve terminals was found in the three species with a concentration-dependent decrease and increase induced by carbachol and scopolamine, respectively. Using the alpha 2-adrenoceptor stimulating and blocking agents clonidine and rauwolscine in rabbit and human detrusor preparations, the presence of prejunctionally located inhibitory alpha 2-adrenoceptors could also be demonstrated. The findings indicate the possibility of a functionally important interaction between cholinergic and adrenergic nerves in the urinary bladder mediated via inhibitory muscarinic receptors on adrenergic nerve terminals.

Animals↗
PubMed1987

Mixed germ-cell tumor of the pineal region. Case report.

The case is presented of a 15-year-old boy with a mixed nongerminomatous germ-cell tumor of the pineal region associated with elevated cerebrospinal fluid and serum levels of the beta subunit of human chorionic gonadotropin. Treatment consisted of initial subtotal resection followed by radiotherapy and systemic chemotherapy with cisplatin, vinblastine, and bleomycin. The patient is alive without evidence of tumor 37 months after his initial diagnosis. A literature review of intracranial embryonal carcinoma and choriocarcinoma provided the rationale for a combined-modality approach to this otherwise lethal neoplasm.

Adolescent↗
PubMed1986

Acute biochemical and functional alterations in the partially obstructed rabbit urinary bladder.

Rapid structural and functional alterations have been noted in several models of partial outlet obstruction. To better characterize the rapid progression of alterations, the partially obstructed urinary bladders of mature NZW male rabbits were studied at 1, 3, 5, 7 and 14 days of outlet obstruction with respect to muscarinic receptor density, DNA, RNA, lipid and hydroxyproline content. Functional characteristics were assessed by measuring the in vitro response of the whole bladder to cholinergic and field stimulation. Wet weight increased eight-fold by day 7, decreasing to four-fold at day 14. Receptor density decreased by 50% by day 1 and remained low throughout. Although DNA concentration varied only slightly from controls, RNA increased four-fold by day 7. Hydroxyproline concentration per mg. tissue decreased in the obstructed bladder, yet total hydroxyproline content of the obstructed bladder significantly increased. Total lipids increased significantly during day 3 through 7 and decreased by day 14. Cystometry revealed a large capacity low pressure system at day 1 which rapidly changed to a low compliance system of lesser volume by day 14. Bladder emptying was significantly impaired in all obstructed specimens. Additionally, electrical field stimulation was significantly less effective than cholinergic stimulation in effecting bladder emptying. The above findings suggest that rapid changes in biochemical parameters occur during the early stage of acute obstruction which may in part be secondary to metabolic or inflammatory alterations in the detrusor. It additionally suggests that the myogenic alterations in partial outlet obstruction are rapid and partially adaptive, while neurogenic alterations appear degenerative and display a lesser degree of short term adaptation.

Animals↗
PubMed1985

Recovery from short-term obstruction of the rabbit urinary bladder.

Partial bladder outlet obstruction is a commonly encountered pathophysiologic state. Recently we have reported on the rapid nature of the contractile and functional changes that occur in the rabbit urinary bladder within one week of chronic partial obstruction. The purpose of this present study is to investigate the ability of the bladder to recover from one week of partial obstruction. Twenty-six mature male white New Zealand rabbits were separated into 3 groups. Each rabbit was anesthetized with ketamine-xylazine and a partial obstruction of the bladder established by gently securing a 2.0 silk suture around the temporarily catheterized bladder neck. The rabbits in group 1 were sacrificed following one week of partial obstruction. For groups 2 and 3, the obstructing suture was surgically removed after one week of obstruction adn the rabbit was allowed to recover for either two or four weeks. At the end of one week of obstruction the bladder displayed a 9-fold increase in tissue mass, 50 per cent reduction in contractile response to bethanechol and a 76 per cent reduction in the ability of the bladder to expel saline. After the two week recovery period, the bladder mass was reduced to approximately twice the control mass, the contractile and pressure responses to bethanechol were returned to control levels, and the ability of the bladder to expel saline recovered to approximately 75 per cent of control levels. No further improvements were observed following the four week recovery period. It appears that although the contractile response recovers completely following the one week obstruction period, the ability of the bladder to empty remains partially impaired.

Adenosine Triphosphate↗
PubMed1985

The effect of parasympathetic decentralization on the feline urinary bladder.

To examine the pharmacologic nature of parasympathetic decentralization on feline vesical smooth muscle, male cats were subjected to bilateral ventral rhizotomy from levels lumbar 7 to coccygeal 1 and studied at 1 and 3 months. By employing manual bladder decompression twice daily, compensatory bladder hypertrophy was absent or minimal in all specimens. In vitro muscle bath studies of bladder body demonstrated no significant end organ pharmacologic supersensitivity to cholinergic or alpha and beta adrenergic stimulation. Membrane receptor assays displayed a rise in muscarinic cholinergic and beta adrenergic receptors at 1 month which decreased at 3 months. The cholinergic receptor data parallels ultrastructural studies which demonstrate early cholinergic nerve terminal degeneration after motor decentralization followed by subsequent regrowth of cholinergic axons. Alpha 1 and alpha 2 adrenergic receptor densities remained constant in control, 1 month, and 3 month preparations. This lack of classic end organ denervation supersensitivity in the decentralized urinary bladder suggests that other mechanisms may be responsible for eliciting a positive response with the clinical denervation supersensitivity test.

Animals↗
PubMed1985

Ultrastructure of vesicourethral innervation. III. Axoaxonal synapses between postganglionic cholinergic axons and probably SIF-cell derived processes in the feline lissosphincter.

Ultrastructurally nonspecialized axoaxonal-type synapses between postganglionic cholinergic axons innervating the lissosphincter and apposed probably SIF-cell derived neuronal processes are described. These processes were considered as the peripheral extraganglionic counterparts of those belonging to type I SIF cell interneurons, described in many mammalian peripheral autonomic ganglia. On this basis, the herein reported cholinergic/probably SIF-cell derived axoaxonal-type synapses are proposed as an auxiliary mechanism of prejunctional catecholaminergic inhibition of the normally excitatory cholinergic (postganglionic parasympathetic) neuroeffector transmission in the feline lissosphincter.

Animals↗
PubMed1984

Ultrastructure of vesicourethral innervation. II. Postganglionic axoaxonal synapses in intrinsic innervation of the vesicourethral lissosphincter: a new structural and functional concept in micturition.

The interrelationships of postganglionic axons in intrinsic neuroplexuses of the vesicourethral lissosphincter ('internal sphincter') were studied ultrastructurally in the cat and rat of both sexes. Direct axoaxonal contracts between cholinergic and adrenergic axons were common in preterminal axon bundles and at neuroeffector junctions. Similar contacts between 2 cholinergic or 2 adrenergic axons were less frequent. Most contacts were ultrastructurally simple, but some had focal areas of very close axolemmal apposition, and some were focally specialized as bona fide chemical synaptic complexes. The axoaxonal contacts are introduced as a complex interaxonal synaptic system that chemically, and possibly also electrically, modulates neurotransmission in postganglionic axons innervating the lissosphincter, presynaptically (prejunctionally) at the infraganglionic level, especially by reciprocal cholinergic/adrenergic axonal interaction. This synaptic system is introduced as a potential, hitherto unrecognized, site of action of autonomic drugs, and as a key factor in the neural mechanism controlling continent closure of the lissosphincter during bladder filling, its opening to initiate and maintain voiding, and its closure to terminate the micturition cycle.

Animals↗
PubMed1984

Granulocytic sarcoma of the hard palate: report of the first case.

A case of granulocytic sarcoma of the hard palate in an elderly woman is presented. The diagnosis was suspected on the basis of histologic findings in routine tissue sections and confirmed by cytochemical and electron microscopic studies. No systemic evidence of myeloid leukemia or of any other myeloproliferative disorder was documented in the patient, who died of an unrelated cause shortly after diagnosis.

Aged↗