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Biomedical subjects

A Ammar

Publications and source records attributed to A Ammar.

At least 37 records · Page 2Linked to original sources
PubMed1999

Empty sella syndrome: does it exist in children?

OBJECT: The empty sella syndrome (ESS) is well documented in adults, and although the same phenomenon of herniation of the arachnoid space into the enlarged sella turcica has been noted in children, it is not widely known that children suffer from this syndrome. Therefore, the aims of this paper are to increase neurosurgeons' awareness of the existence of this phenomenon in children and to add to the scant body of literature on the subject. METHODS: The authors treated 12 children, ranging in age between 2 and 8 years, in whom neuroradiological studies demonstrated an enlarged sella turcica filled with cerebrospinal fluid and herniation of suprasellar and arachnoid spaces. The causes of ESS in these children were high intracranial pressure, neglected or improperly treated hydrocephalus, and suprasellar arachnoid cyst. Primary ESS was found as well. Most of the children presented with headache, abnormal body weight (the majority being underweight), and short stature. The results of hormone assays were normal in all children. CONCLUSIONS: If undiagnosed and untreated, ESS in children may lead to serious consequences, including impairment of pituitary and hypothalamic function and damage to the optic chiasm. It is important to raise awareness in the neurosurgical community about the existence of ESS in children so that it can be diagnosed and treated at an early stage. A classification system for the diaphragma sellae is recapitulated.

Adult↗
PubMed1998

Laparoscopic cholecystectomy for cholelithiasis during infancy and childhood: cost analysis and review of current indications.

Eleven consecutive laparoscopic cholecystectomies (LCs) were performed between January 1994 and June 1996 compared with seven open cholecystectomies (OCs) performed previously at King Khalid University Hospital. The comparison included surgical, clinical, and economic factors, together with a review of the literature. In the laparoscopic group the main indication for cholecystectomy was symptomatic gallstones. Other indications include mucocele of the gallbladder and chronic cholecystitis. A total of eight children in both group had sickle cell disease. The first two LCs were performed in the presence of an experienced laparoscopic surgeon. There is a learning curve to pass through with LC. The operating time for LC ranged between 65 and 135 minutes (mean +/- SD 89.81 +/- 21.89 minutes). There was no major morbidity or mortality. The average postoperative parenteral analgesia required for LC (50.45 +/- 24.57 mg) was significantly less than for OC (135.14 +/- 62.02 mg), and the mean length of hospitalization for LC was significantly shorter than that for OC (1.68 +/- 0.46 vs. 6.07 +/- 0.30) days. Although the average operative cost per LC (2522 SR) was significantly more expensive than for OC (350 SR), the ultimate cost of LC was significantly less than for OC (5790.00 +/- 787 vs. 12,343 +/- 139 SR) because the total period of hospitalization was much shorter. In conclusion, LC is safe, effective, and less expensive than OC and therefore is the approach of choice for cholecystectomy in children.

Child↗
PubMed1998

Psychological assessment (MMPI-2) of male African-American substance-abusing patients with and without histories of childhood physical abuse.

Twenty-nine drug addicted patients in a VA substance abuse program with a history of childhood physical abuse were compared to 29 drug addicted patients without a history of childhood abuse, using the MMPI-2 as a measure of personality traits and functioning. Drug addicted patients with an abuse history showed psychological maladjustment on almost all measures and at greater levels of intensity and severity than the nonabused group. We conclude that drug addicted patients who have been abused represent a unique subset of the drug addicted population and may require targeted psychological treatment for residual problems associated with childhood abuse. This may then also improve the efficacy of substance abuse treatment as well.

Adaptation, Psychological↗
PubMed1998

Comparative clinical pharmacology of rocuronium, cisatracurium, and their combination.

BACKGROUND: The comparative clinical pharmacology of cisatracurium and rocuronium and their combinations has not been reported. In this study, the authors compared the relative potency and the clinical profile and characterized the interaction of both drugs. METHODS: Two hundred twenty adults classified as American Society of Anesthesiologists physical status I and anesthetized with propofol-fentanyl-nitrous oxide were studied. In part 1, the neuromuscular-blocking effects of cisatracurium and rocuronium were assessed after administration of bolus doses of 20-50 microg/kg and 100-300 microg/kg, respectively. In part 2, we compared the time course of 1xED50, 1, 1.5, and 2xED95 doses of both drugs (where ED50 and ED95 are, respectively, the doses producing 50% and 95% depression of the first twitch height [T1]). In part 3, equieffective combinations of both drugs were studied to characterize their interaction. RESULTS: The calculated ED50 values and their 95% confidence intervals were 111 (107-115) and 26.2 (25.8-26.5) microg/kg [corrected] for rocuronium and cisatracurium, respectively. Compared with equipotent doses of cisatracurium, rocuronium had a faster onset, and a faster spontaneous T1 and train-of-four recovery times that were significant except at maximum recovery with the 2xED95 dose. The interaction between rocuronium and cisatracurium was synergistic, and the time profile of the combination group was different from that of the single-dose groups. CONCLUSIONS: Cisatracurium is four to five times more potent than rocuronium. Rocuronium had a faster onset of action, a shorter clinical duration, and a faster spontaneous recovery rate compared with equipotent doses of cisatracurium.

Adult↗
PubMed1997

The influence of different cultures on neurosurgical practice.

It is popularly believed that advances in technology and the increasingly widespread availability of such technology will lead to a lessening of the influence of culture on the practice of medicine. However, this spread of technology is in fact having the opposite effect, since it is more likely that a given patient will receive treatment in a different cultural community than his or her own, possibly administered by care-givers from yet another culture. The cultural backgrounds of the patients, medical staff, disease, community and technology all play a part in influencing the treatment and its outcome. This paper attempts to highlight some of the cultural factors that most influence medical treatment and to suggest ways in which the negative effects of the impact of culture on medicine can be overcome.

Attitude of Health Personnel↗
PubMed1997

Autocrine IL-2-dependent growth of a newly established CD3+, CD16-, CD56+, CD57+, J(H)-, TCRbeta-, TCRgamma- leukemia cell line (NOI-90).

Leukemic cells from a 45-year-old male patient with a CD3+, CD56+, CD57+, CD7+ acute lymphoblastic leukemia were cultured in vitro in the absence of any added growth factor for up to 6 years and a continuous lymphoblastoid cell line (NOI-90) was established. NOI-90 cells have the same phenotype and karyotype as initial leukemic cells. Southern blot of DNA from NOI-90 cells showed that TCRbeta, TCRgamma, and J(H) were in germ line. Two and 25% of NOI-90 cells were positive when stained with the IOT14 and 7G7/B6 moAbs, which recognize the CD25 molecule (IL-2R alpha chain); moreover, 4% and 13% of the cells were positive when stained with the TU-27 and mik beta3 moAbs which recognize the CD122 molecule (IL-2Rbeta chain). Equilibrium binding experiments with radiolabelled IL-2 revealed the presence of a small number of high affinity IL-2R on both fresh and continuously growing cells. Media conditioned by NOI-90 cells could induce proliferation of an IL-2-dependent cell line and this IL-2 activity could be detected by a sensitive immunoenzymatic assay using antibodies recognizing distinct epitopes of IL-2. Moreover, IL-2 activity could be adsorbed by immunoaffinity on anti-IL-2 polyclonal purified IgG and the retained molecule displayed a m.w. of 14.5 kDa in SDS-PAGE. In addition, IL-2 immunoreactive molecules could be revealed in the cytoplasm of the cells. Finally, IL-2 fixed on the cell membrane could be detected by indirect immunofluorescence. Although added IL-2 could not induce cell proliferation, monoclonal antibodies against CD25, CD122 and IL-2 could specifically inhibit spontaneous cell proliferation in a dose-dependent manner. NOI-90 cells failed to demonstrate any cytotoxic activity against the K-562, Raji or Daudi cells. These findings indicate that NOI-90 cells are of non-T, non-B, origin lacking NK activity but proliferate under an autocrine pathway which involves, at least partly, the IL-2/IL-2R system.

CD3 Complex↗
PubMed1997

Comparison of suxamethonium and different combinations of rocuronium and mivacurium for rapid tracheal intubation in children.

The use of suxamethonium in children is associated with undesirable side effects. The synergistic effect of a rocuronium-mivacurium combination can be considered as an acceptable alternative to suxamethonium in clinical practice. The calculated ED50 of the rocuronium-mivacurium mixture was only 62% of the predicted value assuming a purely additive interaction. The use of this combination has not been evaluated in children. In this two-part study, we assessed the intubating conditions and pharmacodynamics of suxamethonium, rocuronium, mivacurium or a rocuronium-mivacurium combinations in children. We studied 120 ASA I children of both sexes, aged 3-10 yr. Children were premedicated with trimeprazine 2 mg kg-1 orally, and received fentanyl 2 micrograms kg-1 and propofol 2 mg kg-1 for induction of anaesthesia. They were allocated randomly to receive one of the following drugs or drug combinations: suxamethonium 1.0 mg kg-1, mivacurium 0.2 mg kg-1, rocuronium 0.6 or 0.9 mg kg-1, mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 or mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1. In part 1, 60 s after administration of the neuromuscular blocking drug or drug combination, tracheal intubation was performed in 60 children by mimicking rapid sequence induction, and intubating conditions were evaluated by a blinded investigator according to a standard score. In part 2, neuromuscular monitoring was established before administration of neuromuscular blocking agent(s) and the time from injection of drug or drug combination until complete ablation of T1 (onset) and recovery of T1 to 25% (duration) were recorded in another 60 children. The frequency of distribution of excellent or good intubating conditions in the higher dose of rocuronium and the combination groups were similar to those in the suxamethonium group, but significantly different (P < 0.05) from those in the mivacurium group. Mean onset time was faster in the suxamethonium (55.1 (SD 11.4) s), rocuronium 0.9 mg kg-1 (70.5 (37.7) s), mivacurium 0.1 mg kg-1 with rocuronium 0.3 mg kg-1 (67 (35.9) s) and mivacurium 0.15 mg kg-1 with rocuronium 0.45 mg kg-1 (55 (26.7) s) groups compared with the mivacurium 0.2 mg kg-1 (116 (26.8) s) and rocuronium 0.6 mg kg-1 (97.9 (29) s) groups. This study demonstrated that the combination of rocuronium 0.45 mg kg-1 and mivacurium 0.15 mg kg-1 could possibly be considered as an acceptable alternative to suxamethonium when rapid sequence induction of anaesthesia is indicated in children because it provides uniform excellent intubating conditions and complete neuromuscular block in < 60 s.

Androstanols↗
PubMed1997

Purine and pyrimidine nucleotide-sensitive phosphoinositidase C in ampulla from frog semicircular canal.

A microassay was developed to screen the abilities of ATP analogues to stimulate phosphoinositidase C in single ventral regions (including dark cells and sensory cells) of ampullas microdissected from posterior vertical semicircular canals of Rana ridibundo and labeled with myo-[3H]inositol. ATP induced a dose-dependent and saturable increase of total [3H]linositol phosphate production accompanied by an equivalent decrease in the [3H]phosphoinositide pool. The rank order of analogues revealing agonistic potencies for phosphoinositidase C activation was as follows: uridine 5'-triphosphate > or = adenosine 5'-O-[3-thiophosphate] tetralithium > adenosine 5'-O-[2-thiodiphosphate] trilithium > or = ATP > or = ADP = inosine 5'-triphosphate > or = guanosine 5'-triphosphate > or = 2-methylthio-adenosine 5'-triphosphate tetrasodium > or = 2'-desoxy-thymidine 5'-triphosphate > or = cytidine 5'-triphosphate = (alpha, beta)-methyl ATP > AMP, whereas adenosine 3',5'-cyclic monophosphate and adenosine were almost devoid of activity. For antagonists, 1,4'-diisothiocyanostilbene-2, 2'-disulfonic acid was far more active than suramin for competitive inhibition of ATP-induced enzyme stimulation, whereas reactive blue 2 acted as a noncompetitive inhibitor. Results indicate that the putative P2 receptors triggering phosphoinositidase C activation in ventral ampullary epithelium from frog semicircular canal exhibit mainly the functional properties of P2Y and P2U receptors.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

[Primary leiomyosarcoma of the small intestine in a child].

BACKGROUND: Leiomyosarcomas of the digestive tract are very rare in children. They must be differentiated from benign tumors (leiomyoma, schwannoma...) and from other malignant tumors, sometimes with the aid of immuno-histochemical study. CASE REPORT: A five-year old girl suffered from an abdominal mass associated with fever and alteration of the general condition. An ileal tumor, 8 cm in diameter, was resected. Histological and immunohistochemical studies (anti-vimentin antibodies, anti-actin antibodies and PS100) confirmed the diagnosis of leiomyosarcoma. Uncomplete adjuvant chemotherapy failed to prevent relapse of the tumor. CONCLUSION: This case confirms the bad prognosis of such a tumor.

Child, Preschool↗
PubMed1996

The relationship of the buccal branch of the facial nerve to the parotid duct.

PURPOSE: This cadaver dissection studied the relationship of the buccal branch of the facial nerve to the parotid duct and its relevance to surgical procedures in this area. MATERIALS AND METHODS: Ten cadaveric heads (twenty sides) were dissected. The superficial tissues were removed, and the buccal branch of the facial nerve and the parotid duct were identified. The vertical and horizontal relationships were recorded and analyzed. RESULTS: Eighty-five percent of the cadavers had a single buccal branch of the facial nerve, whereas 15% had two branches. In 75% of cases, the nerve was inferior to the duct as it emerged from the parotid gland, whereas in 25% of cases the nerve crossed the duct, usually from superior to inferior. CONCLUSION: The buccal branch of the facial nerve has a close relationship with the parotid gland for over 2.5 cm after it emerges from the parotid gland; it normally lies inferior to the duct. This relationship is of importance in performing parotid gland surgery, parotid duct surgery, and some facial cosmetic surgery.

Cheek↗
PubMed1996

Prolonged intrauterine transabdominal ventricular external drainage. A method to decompress dilated fetal ventricles.

Advances in diagnostic procedures to detect intrauterine hydrocephalus have compelled neurosurgeons to intervene in order to preserve precious neural tissue. We present the first case (to the best of our knowledge) of a successful decrease in intracranial pressure and head circumference by repeated transabdominal intrauterine external drainage. The mother tolerated the procedure well. No complication occurred from the procedure. This method may temporarily decrease the intracranial pressure and head circumference in utero, preserve neural tissue and facilitate normal vaginal delivery. The literature of intrauterine intervention in hydrocephalic fetuses is reviewed.

Cerebral Ventricles↗
PubMed1996

[False hydatic aneurysm of the thoraco-abdominal aorta].

Arterial complications of hydatic disease are rarely encountered. We report a false hydatic aneurysm of the thoracoabdominal aorta revealed by ischemic embolism of the lower limbs. Surgical treatment included aorto-aortic prosthesis and albendazol for 6 months. Results at 18 months are excellent with negative hydatic serology. In endemic areas, hydatic disease is a possible cause of false aneurysms. Long-term surveillance is required after curative surgery and medical treatment.

Adult↗
PubMed1995

Divergent effects of chronic amiodarone administration on systolic and diastolic function in patients with heart disease.

The purpose of this study was to determine the effects of chronic amiodarone treatment on systolic and diastolic function in patients with cardiac disease undergoing treatment for resistant ventricular arrhythmias. Previous studies have shown that chronic amiodarone treatment either has no effect or increases left ventricular ejection fraction, but the effects on diastolic properties of the ventricle have not been defined. Twelve male patients were given loading doses of amiodarone followed by a maintenance regimen. Serial measurements of heart rate, blood pressure, and indexes of systolic and diastolic function were measured by Doppler echocardiographic techniques at baseline conditions and at 2, 8, and 12 weeks of drug therapy. Changes in altered thyroid state were excluded by serial determinations of thyroid function. Amiodarone increased left ventricular ejection fraction (+16%, p < 0.01 by 8 weeks), decreased presystolic ejection period/left ventricular ejection time (-12%, p < 0.01 by 8 weeks), and increased velocity of circumferential fiber shortening (+22%, p < 0.05 by 8 weeks). Amiodarone decreased mitral inflow velocity peak E/peak A (-7%, p < 0.01 by 12 weeks), and increased deceleration and isovolumic relaxation times incrementally (+36% [p < 0.001] and +23% [p < 0.001], respectively, at 12 weeks). Chronically administered amiodarone can improve systolic function and exert a negative lusitropic action in patients with heart disease.

Aged↗
PubMed1995

Vasotocin-sensitive adenylate cyclase in frog glomeruli.

Adenylate cyclase sensitivity to neurohypophyseal hormones was investigated in isolated glomeruli and in nephron segments microdissected from collagenase-treated kidneys of Rana ridibunda. Vasotocin treatment increased adenylate cyclase activity in glomeruli and in collecting ducts and did not modify it in proximal convoluted tubules and in early and late distal tubules. In glomeruli, the hormonal stimulation resulted mainly in a decrease in the Km value for adenylate cyclase, which means a higher affinity for substrate (ATP) to the enzyme, whereas the response to forskolin was accounted for by increases both in affinity for substrate and in maximal adenylate cyclase velocity. The homologous neurohypophyseal hormones stimulated frog glomerular adenylate cyclase with the following rank order of affinities: hydrin 1 > or = AVT = AVP > or = hydrin 2 > OT > or = mesotocin > isotocin; structural analogs dDAVP, VDAVP, dVDAVP, and [Phe2,Orn8]VT had weak agonistic properties, [Thr4,Gly7]OT was inactive, and the antagonists OVTA, d(CH2)5Tyr(Et)2VAVP, and des-Gly9-d(CH2)5Tyr(Et)2VAVP inhibited hormone-induced enzyme activation with similar apparent inhibition constants. The vasotocin receptors triggering adenylate cyclase stimulation in frog glomeruli differ pharmacologically from V2 vasopressin receptors of mammalian kidneys and may also differ from V2-like vasotocin receptors of amphibian skin and urinary bladder.

Adenosine Triphosphate↗
PubMed1995

Intraventricular migration of VP shunt.

The proximal migration of a ventriculoperitoneal shunt into the ventricles is very rare. Only 5 cases have been previously reported [4, 8, 10, 11]. We believe that this unusual phenomenon has not been well-studied in the literature. We report a case of a 16-month-old baby girl who suffered a shunt malfunction due to complete migration of the VP shunt into the lateral ventricle. This case and the other 5 cases are studied, and a possible cause is hypothesized. The group of patients at risk is also identified and methods of management are reported.

Female↗
PubMed1995

A long-term complication of burying a shunt valve in the skull.

One of the most common causes of shunt malfunction is infection; a major contributing factor to this infection in neonates is scalp necrosis over the valve site. One of the methods recommended to avoid this requires the burying of the valve in the skull bone. We present a case of a long-term complication from this procedure: the shunt slowly disconnected, over a prolonged period, leading to the formation of the fibrous tunnel which enabled the shunt to function intermittently. We recommend that the practice of burying the shunt into the skull bone is be reconsidered.

Cerebrospinal Fluid Shunts↗
PubMed1995

Ammar shunt: an option to overcome shunt complications in premature and term neonates.

It has been hypothesized, and generally accepted, that the final outcome of the treatment of hydrocephalus is to a great extent related to the earliness of intervention and treatment. However, there is special concern regarding the higher risk of infection and shunt malfunctions in neonates as compared with older infants. Therefore, two new shunt systems have been designed specifically to tip the balance in favor of early shunting. The first shunt is made for premature neonates and the second for neonates in general. The general characteristics of these two shunts are: (1) the entire shunt is a low-pressure valve, with double distal slit valves; (2) the shunts are made of soft silicon material; (3) they are of very small configuration, without any compressing elements which may lead to skin necrosis over the shunt; (4) no metal has been used in them, so they are MRI compatible.

Cerebrospinal Fluid Shunts↗