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Biomedical subjects

A Hamdi

Publications and source records attributed to A Hamdi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Plasma concentrations of bupivacaine and its enantiomers during continuous extrapleural intercostal nerve block.

Plasma concentrations of bupivacaine have been measured in 12 patients given bupivacaine through a paravertebral catheter placed under direct vision at thoracotomy. After an initial bolus of 0.5% bupivacaine 20 ml, mean (SEM) Cpmax was 1.45 (0.32) micrograms ml-1 and median (range) tCpmax was 25 (10-60) min. A concentration of 4.43 micrograms ml-1 measured in one patient was not associated with toxic signs. During continuous infusion of bupivacaine for 120 h, Cpmax was 4.9 (0.7) micrograms ml-1 and tCpmax 48 (5-96) h. No symptoms or signs of toxicity occurred. Separate measurement of R- and S-bupivacaine concentrations demonstrated significantly different concentration-time profiles.

Adult↗
PubMed1993

[Abdominal cystic lymphangioma in children].

Cystic lymphangioma is a rare tumour (6% of benign tumours in children), frequently situated in the cervical or axillary region and exceptionally intraabdominal. It arises due to a congenital defect in the connection of the primary lymphatic channels with the central collecting system. It presents clinically either in the form of a pseudo-appendix or pseudo-ascites syndrome or in the form of an abdominal tumour with or without compression of adjacent structures. It can now be easily diagnosed by ultrasonography. Treatment is well defined and consists of surgical resection of the isolated lymphangioma or associated with the adjacent intestine, depending on the site of the tumour. It has a good prognosis.

Abdominal Neoplasms↗
PubMed1992

Decreased striatal D2 dopamine receptors in obese Zucker rats: changes during aging.

The specific binding of [3H]YM-09151-2 was used to investigate the possible differences in age-associated changes in striatal D2 dopamine (DA) receptor properties in genetically obese (fa/fa) Zucker rats and their lean (Fa/?) littermates. The maximal binding sites (Bmax) of D2 DA receptors was found to decline with age in both obese and lean rats; the rate of decline in receptor Bmax was slightly higher in lean than obese rats. However, the Bmax of D2 DA receptor in 6-, 12- and 18-month-old obese rats was significantly lower compared to the age-matched lean rats. These data indicate that obesity decreases the number of striatal D2 DA receptors without affecting the rate at which receptor number decreases with age.

Aging↗
PubMed1992

A low protein-high carbohydrate diet decreases D2 dopamine receptor density in rat brain.

The property of D2 dopamine receptors in the rat brain was evaluated after long-term dietary manipulation. Groups of rats were pair-fed with equicaloric diet containing low protein (8%)-high carbohydrate, high protein (52%)-low carbohydrate and normal protein (20%) for 36 weeks. The low protein-high carbohydrate fed rats exhibited a significant decrease in the density (Bmax) of D2 dopamine receptor in the striatum (28%) and the mesolimbic regions (36%) with no apparent change in the receptor affinity (Kd). These findings suggest that long-term consumption of a low protein-high carbohydrate diet, by decreasing D2 dopamine receptor density, may be an important determinant of central dopaminergic function.

Animals↗
PubMed1991

Attenuation of pulsatile changes in the density of striatal [3H]GBR-12935 binding sites during chronic ethanol consumption.

Using [3H]GBR-12935 as a selective ligand, we have examined the properties of rat striatal dopamine transporter complex during chronic ethanol consumption. The results of this study show a significant change in the Bmax (maximal binding capacity), but not Kd (affinity) of [3H]GBR-12935 binding sites. The observed changes were pulsatile and they exhibited an increase (144% of control), decrease (80% of control), tendency to increase (111% of control), increase (141% of control), decrease (84% of control), no change (98% of control), and decrease (80% of control) after 1, 2, 3, 4, 6, 8 and 10 weeks of ethanol consumption, respectively. Since the duration of ethanol exposure appears to be an important variable in regulating the properties of dopamine transporter complex, the behavioral changes observed during chronic ethanol intake may vary with time.

Alcoholism↗
PubMed1991

Ontogenic homologous supersensitization of dopamine D1 receptors.

To determine whether prolonged supersensitization of dopamine D-1 receptors could be produced during ontogeny, rats were treated daily, from birth, for 33 consecutive days with the D-1 receptor agonist, SKF 38393 HCl (3.0 mg/kg per day i.p.). These rats were additionally treated at 3 days after birth with the neurotoxin, 6-hydroxydopamine HBr (6-OHDA; 200 micrograms i.c.v., half in each lateral ventricle) or its vehicle. At 6 to 7 weeks from birth a challenge dose of SKF 38393 HCl (3.0 mg/kg i.p.) increased stereotypy scores for a number of behaviors in 6-OHDA-lesioned rats that were treated repeatedly during ontogeny with SKF 38393. These accentuated behaviors included licking, grooming, taffy pulling, jumping, paw treading and locomotion. Although the findings demonstrate an increased sensitivity of D-1 receptors to an agonist, there was no change in the Bmax or Kd for D-1 receptors in the striatum. In rats that were treated during postnatal development with SKF 38393, but not lesioned with 6-OHDA, SKF 38393-induced stereotyped behaviors were not substantially different from control. The neonatally primed rat model may be useful for probing mechanisms of receptor supersensitivity.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1991

Reversed-phase and chiral high-performance liquid chromatographic assay of bupivacaine and its enantiomers in clinical samples after continuous extraplural infusion.

A previously unreported coupled achiral-chiral high-performance liquid chromatographic method has been developed to assay the levels of bupivacaine and its enantiomers in plasma samples, after the local anaesthetic had been given as a continuous extrapleural intercostal nerve block for 4 days, to relieve postoperative pain following thoracotomy. The method has been used to determine maximum, individual enantiomer and steady state levels in conjunction with an assessment of whether accumulation of bupivacaine occurs. An off-line extraction sample preparation is involved before determination of the "total" levels and final sample clean-up on a cyanopropyl silica column prior to "heart cutting" of the bupivacaine peak to a Chiral-AGP column for assay of the enantiomeric ratio. For an initial 5 patient number the mean maximum level was 5.43 micrograms/ml against a reported toxic level of around 5 micrograms/ml, which was reached in 72 h and the S-enantiomer gave slightly increased concentrations over the R-enantiomer for which there is some evidence of higher toxicity.

Adult↗
PubMed1991

Echotomographic and serological population-based study of hydatidosis in central Tunisia.

A population-based echotomographic (ECT) and serological survey of hydatidosis was carried out in a high risk community located in Central Tunisia. 1434 subjects over 5 years of age (93.3% of the population in this age range) underwent an abdominal echotomography (ECT) and a serological test (ELISA with confirmation by counterelectrophoresis). The ECT prevalence rate was 3.5% and increased with age reaching 7.7% in the over 39 years age group. Most subjects (96.0%) had liver cyst(s). The serological prevalence rate was 2.9%. A strong agreement was found between ECT and serological results (Kappa test = 0.449). Taking ECT as a reference, the relative specificity and sensitivity of serology were 99.3 and 62.0 respectively. Most ECT positive seronegative subjects had calcified cysts. These results confirm the presence of highly endemic foci of hydatidosis in Central Tunisia, show a good agreement between serological and ECT results at a population level and demonstrate the high feasibility of ECT as a screening technique.

Adolescent↗
PubMed1991

Potentiation of spiperone-induced oral activity in rats after neonatal 6-hydroxydopamine.

The influence of central dopaminergic fibers on drug-induced oral activity in rats has not been well studied. Rats were treated 3 days after birth with bilateral intracerebroventricular 6-hydroxydopamine (6-OHDA; 134 micrograms total, base form) to destroy dopaminergic fibers in the brain. Control rats received vehicle by the same route. At about 10 weeks of age, a challenge dose of the dopamine D2 receptor antagonist, spiperone (40 micrograms/kg, IP), produced an 8-fold increase in the number of oral movements during a 60-minute observation period, vs. the control group. SKF 38393 (3.0 mg/kg, IP), a D1 agonist, produced the same number of oral movements as spiperone in the 6-OHDA group, representing a 2.4-fold increase over the controls. The Bmax and Kd for both D1 and D2 receptors was not changed in rat striatum by neonatal 6-OHDA treatment, even though dopamine content was reduced by 96%. These findings demonstrate that oral activity in rats can be greatly altered, even when there is no change in absolute numbers of D1 and D2 receptors and no change in the ratio of D1:D2 receptors.

Animals↗
PubMed1991

Antibodies against synthetic peptides predicted from the nucleotide sequence of D2 receptor recognize native dopamine receptor protein in rat striatum.

Two peptides corresponding to amino acid sequences predicted from the nucleotide sequence of the dopamine D2 receptor were synthesized. Peptide I (CGSEG-KADRPHYC) and peptide II (NNTDQNECIIY), corresponding to 24-34 and 176-185 from the NH2 terminus, respectively, were conjugated to keyhold limpet hemocyanin and injected into rabbits. Peptide I showed a greater immunogenic response than did peptide II. Both peptide antibodies exhibited high titer for the homologous antigens, but showed little or no cross-reactivity with heterogeneous peptides. Peptide I antibodies reacted with striatal membrane proteins of apparent molecular masses of 120, 90, 85, and 30 kDa on a western blot. Furthermore, the 90-kDa band was identified as denatured D2 receptor by its high affinity for the D2 selective photoaffinity probe 125I-N'-azidospiperone (125I-NAPS). Photoaffinity labeling of the 90-kDa protein by 125I-NAPS was reduced by 40% in the presence of the peptide I antibody. In addition, evidence is also presented to show the low level of 90-kDa protein in cerebellum which contains little or no D2 ligand binding sites. The antibody to peptide I inhibited the binding of [3H]YM-09151-2, a dopamine D2 receptor selective antagonist, to striatal membranes in a concentration-dependent manner; a 50% inhibition was obtained at a 1:500 dilution of the antisera with 20 pM ligand concentration. The data on the equilibrium inhibition kinetics of [3H]YM-09151-2 binding to striatal membranes were examined in the presence of antibody and showed a 25-30% decrease in Bmax (203.5 +/- 11.0 and 164.6 +/- 3.3 fmol/mg of protein in presence of preimmune and immune sera, respectively) with no change in KD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Imidazoline desensitization of epinephrine responses in rat vas deferens.

Repeated exposure of the rat vas deferens to the imidazoline oxymetazoline (OXY) results in a progressive loss of response which can appear selective for imidazoline agonists. The present study tests the hypothesis that imidazolines produce desensitization through prolonged blockade or inactivation of alpha-1 adrenoreceptors. Repeated exposure to OXY, naphazoline (NPZ) or tetrahydrozoline (THZ) produces a concentration- and time-dependent rightward shift and depression of the (-)-epinephrine concentration-effect curve, suggesting a mechanism of prolonged receptor blockade or inactivation. (-)-Epinephrine Kd values were similar when estimated after either receptor inactivation with phenoxybenzamine or repeated exposure to imidazolines. The differences in the ability of individual imidazolines to produce desensitization (order of potency: OXY greater than NPZ greater than or equal to THZ) do not follow their intrinsic activity (NPZ approximately THZ approximately OXY) or affinity (OXY greater than or equal to NPZ greater than THZ). The ability of individual imidazoline and phenethylamine agonists to produce a response in imidazoline-desensitized rat vas deferens reflects agonist intrinsic efficacy. Desensitization by imidazoline exposure does not affect contraction produced by either KCl or neurokinin A. Imidazolines produce effects similar to receptor inactivation and their desensitization in vas deferens can be explained without invoking an imidazoline subtype of alpha-1 adrenoreceptor.

Adrenergic alpha-Antagonists↗
PubMed1991

[Pseudo-tumoral xanthogranulomatous pyelonephritis. Apropos of a case].

The authors report the case of a 20 year old patient in whom the clinical findings combined with the radiological signs, suggested the diagnosis of renal cancer. The histological findings after nephrectomy established the diagnosis of xanthogranulomatous pyelonephritis. This disease may rarely give the appearance of a renal tumor. This points out the importance of identifying this lesion in preoperative staging to avoid carcinologic surgery and all of its difficulties.

Adult↗
PubMed1991

[A case of esophageal duplication discovered in a newborn].

A case of esophageal duplication discovered in the neonatal period is reported and discussed. This infrequent malformation (9% of all childhood mediastinal tumors) is an entoblastic duplication of the digestive tract and is often accompanied with spinal malformations. The duplication may be either cystic or tubular; the latter form usually opens into the normal esophagus. The most common clinical manifestations are respiratory symptoms caused by compression. The diagnosis, suggested by the findings on the plain chest film and osephageal opacification, is confirmed by the ultrasound examination and, above all, the CT scan. The treatment of this malformation is surgical. Reconstruction may be difficult but overall results and prognosis are excellent.

Abnormalities, Multiple↗
PubMed1991

[Long-term outcome of surgically treated peptic ulcer. Review of a series of 419 patients operated for peptic ulcer].

The authors report an analysis of 419 cases of operated peptic ulcer. 68.78% of patients had a mean follow-up of 4 years. After clinical and endoscopic examination, the results of the survey were assessed on the basis of various parameters, which demonstrated that the results of surgery were related to socio-occupational problems, smoking, the site of the ulcer, the stage, the history of the ulcer prior to the operation, the conditions of the operation and obviously the surgical technique used.

Adolescent↗
PubMed1991

[Value of posterior vertical lumbar incision in renal surgery. Based on a series of 1,126 cases].

The authors report their experience of 1,126 cases of posterior vertical lumbar incision. The essential indication for this approach is stones in the renal pelvis or lumbar ureter (788 cases). The authors subsequently extended the indications for this incision to all plastic operations on the pyeloureteric junction (56 cases) and the extraction of certain staghorn calculi (114 cases). The posterior approach is anatomically simple and direct. It has the advantage of causing less muscular mutilation with a simpler postoperative course.

Adolescent↗
PubMed1990

[Hydatic cyst of the psoas muscle. Apropos of 3 cases].

In the three patients, the localization and the hydatic origin have been determined by preoperative ultrasonography in two instances, the diagnosis was confirmed by CT scan. Ultrasonography and computed tomography allowed a direct and simple surgical approach of the cyst.

Adult↗
PubMed1990

[Posterior vertical lumbotomy in pediatric practice. Apropos of a series of 294 cases].

The study involves 294 cases. Essentials indications of posterior approach were for pelvic stones or lumbar ureteral stones 198 cases. Theres used this approach for abnormalities in the uretero-pelvic-jun (32 cases) and some staghorn srones (24 cases). The lateral posterior vertical lumbotomy passesses the advantage over classical lateral lumbotomy of being less disturbing to muscle, being less painful postoperatively stay.

Adolescent↗