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Biomedical subjects

M Hassan

Publications and source records attributed to M Hassan.

At least 73 records · Page 4Linked to original sources
PubMed1999

Thickened pituitary stalk on magnetic resonance imaging in children with central diabetes insipidus.

Magnetic resonance imaging (MRI) has revealed isolated pituitary stalk (PS) thickening (PST) in certain cases of idiopathic or secondary central diabetes insipidus (DI) due to infiltrative processes. Twenty-six children with DI and PST underwent cerebral MRI at the age of 8 +/- 4 yr and were followed (n = 24) by clinical and MRI evaluation, respectively, for 5.5 +/- 3.6 and 3.0 +/- 2 yr in the absence of any treatment other than hormonal substitutive therapy. Patients were subdivided into groups according to the etiology of the DI: germinoma (n = 4), Langerhans' histiocytosis (n = 5), or idiopathic DI with PST (n = 17). Complete anterior pituitary evaluation for 24 of the 26 patients revealed those suffering from associated GH deficiency (n = 14; with germinoma, n = 1; histiocytosis, n = 3; idiopathic, n = 10) and from multiple hormone deficiencies (n = 7; with germinoma, n = 3; histiocytosis, n = 1; idiopathic, n = 3). At the first MRI evaluation, PS enlargement varied from 2.2-9.0 mm at a proximal (n = 10), distal (n = 2), or middle (n = 6) PS level or along the entire PS (n = 8). The intrasellar content, which usually reflects the anterior pituitary gland, was normal (n = 12), small (n = 8), or enlarged (n = 6). At the last evaluation, a change in MRI features was found in 16 patients; morphological and/or signal changes in the PST (n = 16, of whom 6 showed an increase in PST) and changes in anterior pituitary gland size (n = 8; increased, n = 3; decreased, n = 5) were noted. The presence of a growing suprasellar mass with progressively enlarging PS was demonstrated in the 6 patients who had shown increased PS enlargement 1.8 +/- 1.6 yr after the first MRI. For 4 of them, a diagnosis of germinoma was made 1.3 +/- 0.6 yr after PST identification by MRI performed after the onset of DI, but the other 2 patients showing a suprasellar mass were still categorized as idiopathic at the final clinical evaluation performed 7.8 and 12.3 yr, respectively, after DI onset. In 10 patients (all but 1 with Langerhans histiocytosis, showing idiopathic DI), the PS enlargement was diminished after 2.0 +/- 1.9 yr of MRI follow-up, with a complete reversal of PS enlargement for 5 of them. Suprasellar mass invasion of the PS was related to multiple hormone deficiency. Although intrasellar content enlargement was observed in most patients with germinoma, a normal or small anterior pituitary gland showed no clear relationship to either clinical histories or laboratory values. In conclusion, the natural history of idiopathic isolated central DI with PST is unpredictable. Although germinoma should always be considered during the first 3 yr of follow-up in patients showing isolated DI with PST requiring repeated investigations every 3-6 months, it remains a less frequent etiology for 15% of the cases.

Adolescent↗
PubMed1999

Growth hormone deficiency with ectopic neurohypophysis: anatomical variations and relationship between the visibility of the pituitary stalk asserted by magnetic resonance imaging and anterior pituitary function.

In GH-deficient children showing ectopic posterior pituitary hyperintense signal (EPP), the anatomical details of the pituitary-hypothalamic region and the relationship between the visibility of the pituitary stalk and anterior pituitary function were studied by magnetic resonance imaging (MRI). The absence or presence of the pituitary stalk was recorded by MRI before and after the injection of gadolinium in 25 children with GH deficiency and EPP at the age of 8.7+/-5.0 yr (16 males and 9 females). Patients were classified into 2 groups according to the presence (group 1; n = 14), or the absence (group 2; n = 11) of pituitary stalk visibility after gadolinium injection. Most patients in group 1 (12 of 14) demonstrated isolated GH deficiency, whereas all but 1 patient in group 2 showed multiple anterior pituitary hormone deficiency. The prevalence of a normally sized adenohypophysis was higher in group 1 than in group 2 (50% vs. 9%; P<0.05). Although the EPP was found at the median eminence in all group 2 patients, it was visualized in group 1 at different levels of the pituitary stalk in 60% of cases (8 of 14; at the proximal end of the pituitary stalk, n = 4; in the middle of the pituitary stalk, n = 2; at the distal end of the pituitary stalk, n = 2). This demonstrates that the ectopic posterior pituitary migration abnormality may be complete or partial. In conclusion, although the pathogenesis of GH deficiency with EPP remains unclear, these results suggest that in cases of GH deficiency associated with ectopic posterior pituitary hyperintense signal, patients with no visible pituitary stalk on MRI after gadolinium injection present a more severe form of the disease in childhood associated with multiple anterior pituitary hormone deficiency, whereas visibility of the pituitary stalk is related to isolated GH deficiency. Nevertheless, careful follow-up of these latter patients is necessary, as the natural history of the disease is not established until adulthood.

Adolescent↗
PubMed1999

Newer quinolones in the long term prophylaxis of recurrent urinary tract infections (UTI).

Up to 10% of premenopausal women experience recurrent symptomatic urinary tract infection (UTI), mainly due to reinfection from the faecal flora. The recently introduced fluoroquinolones possess a wide spectrum of activity against most uropathogens and achieve high urinary concentrations for extended time periods. Our initial study, conducted between 1993 and 1995, was designed to compare the efficacy and safety of oral pefloxacin 800mg once weekly with oral ciprofloxacin 125mg once daily, over a 12-month prophylactic course in women with recurrent UTI. A 12-month reinfection-free period was achieved in 83.3% of pefloxacin patients and in 78.9% of ciprofloxacin patients. The present study, which commenced in 1996, was designed to compare pefloxacin 400mg with oral fleroxacin 400mg once weekly. Prophylaxis was maintained for 12 months. There are no statistically significant differences between the 2 regimens in terms of efficacy and safety. The most frequently isolated pathogens causing breakthrough reinfections were Escherichia coli and Enterococcus spp. Adverse effects observed were mostly neuropsychic (insomnia) and gastrointestinal. In both studies, there was no evidence of emergence of quinolone-resistant organisms in the urine or rectal flora, even after 12 months of chemoprophylaxis.

4-Quinolones↗
PubMed1999

Short needles (8 mm) reduce the risk of intramuscular injections in children with type 1 diabetes.

OBJECTIVE: To study whether 8-mm needles can reduce the frequency of intramuscular injections in diabetic children. RESEARCH DESIGN AND METHODS: We conducted a prospective crossover study in 50 children whose BMI was < or = 60th percentile to compare two lengths of needles (12.7 and 8 mm) regarding the occurrence of intramuscular injections as assessed by ultrasonography. RESULTS: The frequency of intramuscular injections was 86% with the 12.7-mm needles and 38% with the 8-mm needles. The frequency of intramuscular injections was significantly reduced when using the 8-mm needles in the arms (P < 0.01) and thighs (P < 0.001). The efficiency of 8-mm needles, as defined by an intramuscular injection with a 12.7-mm needle and a subcutaneous injection with an 8-mm needle, was found for half of the children who injected in the arm and for two-thirds of the children who injected in the thigh. The subcutaneous tissue (SQT) thickness measured by ultrasonography with a skinfold was significantly higher (9.8 +/- 2.2 mm) in the group in which the 8-mm needles were efficient than in the group in which they were not efficient (6.8 +/- 2.1 mm, P < 0.0001). The efficiency of the 8-mm needle was not related to age, sex, BMI, percentile of BMI, injection device, or injection site. The sensibility and specificity of SQT thickness in predicting the efficiency of the 8-mm needles were both 79%. CONCLUSIONS: Needles that are 8 mm long significantly reduce the risk of intramuscular insulin injection in slim or normal-weight (BMI < or = 60th percentile) diabetic children and adolescents.

Adolescent↗
PubMed1999

[The value of orbital ultrasonography in ethmoid sinusitis in children].

PURPOSE: To assess the value of orbital sonography (US) compared to CT in the management of children with ethmoid sinusitis. MATERIAL AND METHODS: A total of 13 consecutive patients admitted for non-complicated ethmoid sinusitis (absence of visual or neurological symptoms) were prospectively evaluated at US and CT. RESULTS: Three patients had no evidence of postseptal involvement at US. Ten patients had variable degree of postseptal involvement at US: hypoechoic area or fluid collection in the extraconal fat along the medial orbital wall. Results were confirmed at CT in all patients. CONCLUSION: US is useful to confirm the presence of postseptal involvement in patients with ethmoid sinusitis. Contrary to CT, findings at US remain non-specific as to the nature of involvement. Nonetheless, US is helpful for patient management.

Adipose Tissue↗
PubMed1999

Recurrent abdominal pain and Helicobacter pylori infection in children.

UNLABELLED: Recurrent chronic upper abdominal pain is a common problem in children and it has been associated with Helicobacter Pylori gastritis. AIMS AND OBJECTIVES: We under took this study, to find out the prevalence of Helicobacter pylori gastritis in children with recurrent chronic upper abdominal pain, in our set up. MATERIAL AND METHODS: This was prospective study carried out at KRL Hospital, Islamabad. Forty three children with chronic recurrent upper abdominal pain (age 3 to 14 years), underwent diagnostic gastroscopy and antral biopsies with histopathology, over a period of one year. Another 42 children of the same age group were taken as control group. Fifteen patients, who tested positive for H. pylori were tested for IgG antibodies in whole blood and compared with 15 patients having negative histology for H. pylori. RESULTS: Thirty two (75%) children tested positive for H. pylori, in the test group, as compared to 17 (40%) histological positives in the control group (P = < 0.1). The patients who were tested for IgG antibodies showed that this test has 93% sensitivity, 60% specificity and a negative predictive value of 90% as compared to histological identification. CONCLUSION: Recurrent chronic upper abdominal pain in children, in our population has a significant association with Helicobacter pylori gastritis. Testing of IgG antibodies for H. pylori in whole blood can be used as initial, non invasive screening test for this organism.

Abdominal Pain↗
PubMed1999

Specific anti-Toxoplasma antibodies in relation to infection and reinfection using different infective stages.

The possibility of rat re-infection with different Toxoplasma gondii stages was studied in this work. Two groups of rats were infected with either intra-peritoneal injection of 1000 trophozoites of virulent Toxoplasma strain or 1000 oocysts through oral routes. IgA, IgM and IgG were detected 15, 30, 60 and 120 days post infections. IgA and IgM appeared as early as 15 days post infection but declined afterwards. IgA antibody response was more prominent with oocyst infection and IgM was more prominent with tachyzoite infection with insignificant statistical difference. On the other hand, IgG started to increase 60 days post infection, then increased gradually till the end of the experiment (120 days). The primary orally infected rats were either re-infected orally with oocysts or intra-peritoneal trophozoites and re-examined after 15 and 120 days for the same immunological parameters. Those rats which primary infected with intra-peritoneal trophozoites were re-examined after oral infection with oocysts or injection of trophozoites intra-peritoneal. The level of IgA and IgM in one rat of group A and 2 rats of group B were significantly increased and this occurred in presence of anti-Toxoplasma IgG from the primary infection. In this study, the rats were lab-bred so, the factors affect the immune system could be under control, also strain variability was excluded as the infection was only by one strain, and as the IgG level was high, these rats were presumed to be immune from the primary infection. So, the rats which became positive after challenge most probably re-infected.

Animals↗
PubMed1998

Iodixanol in paediatric excretory urography: efficiency and safety compared to iohexol.

BACKGROUND: Iodixanol (Visipaque, Nycomed Imaging AS, Oslo, Norway) is a new non-ionic and isotonic X-ray contrast medium. OBJECTIVE: To assess its safety and efficacy for paediatric excretory urography. MATERIALS AND METHODS: A three-centre trial in which 72 patients were randomised into three parallel groups: iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iohexol 300 mgI/ml (Omnipaque, Nycomed Imaging, Oslo, Norway). Doses ranging from 1 to 3 ml/kg never exceeded 50 ml. Pulse rate and blood pressure were recorded before, during, and after the examination. Adverse events, including injection associated discomfort, were recorded during and up to 24 h after the examination. The diagnostic quality of the urograms was assessed on a four-level scale. RESULTS: No serious adverse event occurred in any of the three groups. One patient who was given iodixanol 270 mgI/ml, three who received iodixanol 320 mgI/ml, and one who received iohexol 300 mgI/ml experienced transient adverse events. More than 80 % of the urograms in all three groups were rated "good" or "excellent". CONCLUSION: Iodixanol, either 270 mgI/ml or 320 mgI/ml, is well tolerated and efficacious for excretory urography in children.

Adolescent↗
PubMed1998

Magnetic resonance imaging of the fetus.

Fetal magnetic resonance imaging (FMRI) has gained considerable interest during the last decade, especially in its intracranial applications. Due to its high soft-tissue contrast and presumed safety, FMRI should be accepted as a complementary technique in prenatal diagnosis, useful either to elucidate equivocal findings on routine US studies or to further delineate some pathological entities. Normal patterns of fetal brain maturation, as shown by FMRI, are described because they are of paramount importance to accurately evaluate intracranial diseases. To date, however, FMRI requires specialised facilities and should be considered as an evolving clinical research modality and performed within precise guidelines in a multidisciplinary approach to prenatal pathology.

Brain↗
PubMed1998

Carbohydrate-deficient glycoprotein syndrome type I: a new cause of dysostosis multiplex.

We report on a 1-year-old boy, with carbohydrate-deficient glycoprotein (CDG) syndrome type I due to phosphomannomutase deficiency. Radiologic examination of the skeleton revealed previously unreported bone abnormalities that could be included in a dysostosis multiplex: wide ribs, squared iliac wings, horizontal acetabular roofs, widening and modeling abnormalities of ischial and pubic bones, dorsolumbar kyphosis, and slight hook-like dysplasia of the first lumbar vertebrae. Wormian bones were also present. We suggest that these features may be due to hypoglycosylation of bone proteins and that CDG syndrome type I should be included in the differential diagnosis of dysostosis multiplex.

Congenital Disorders of Glycosylation↗
PubMed1998

Pharmacokinetics and distribution of liposomal busulfan in the rat: a new formulation for intravenous administration.

The plasma pharmacokinetics and tissue distribution of busulfan (Bu) were investigated after intravenous injection of free Bu (D-Bu) and freshly prepared liposomal Bu (L-Bu). Liposomal Bu was prepared using L-alpha-phosphatidylcholine, 1,2-dioleolyl-sn-glycero-3-phosphate, and cholesterol. The liposomes formed were unilamellar vesicles measuring 220 +/- 14 nm in diameter and containing a Bu concentration of 0.31 +/- 0.03 mg/ml. The half-life of Bu in the present formulation was determined to be 8.7 +/- 2.7 days at 4 degrees C. The liposomes in the new formulation were stable for 20 days at 4 degrees C. After the intravenous administration of L-Bu or D-Bu (dissolved in a mixture of DMSO, ethanol, and propylene glycol) to the rats a higher bone marrow exposure to Bu as expressed in AUC marrow/AUC blood was achieved using L-Bu as compared with D-Bu (1.59 and 0.83, respectively). A higher distribution volume was observed for L-Bu as compared with D-Bu (1.39 versus 0.67 l/kg, respectively). The elimination half-lives were significantly longer in both blood and marrow after the administration of L-Bu as compared with D-Bu (2.52 and 3.08 versus 1.53 and 1.75 h, respectively). The new liposomal Bu showed linear pharmacokinetics within the range of 0.5-3.5 mg/kg, which is comparable with that obtained for D-Bu. A slight difference was observed in systemic exposure to L-Bu as compared with D-Bu as expressed in AUC (9.93 and 11.82 microg h ml(-1), respectively). The distribution study using 14C-labeled Bu showed that the radioactivity was significantly higher over 18 h in the bone marrow (3-fold) and spleen (2-fold; P < 0.01) in a comparison of L-Bu with D-Bu. However in the brain, lungs, and heart the distribution of radioactivity after the administration of L-Bu was significantly lower (P < 0.05) than that obtained using D-Bu. On the basis of the present study, the new formulation of liposomal Bu seems to be a promising preparation for clinical trials, since it appears to target bone marrow and spleen with no accumulation in the liver or other organs known for Bu toxicity.

Animals↗
PubMed1998

Pancreaticoduodenal artery aneurysms associated with celiac axis stenosis due to compression by median arcuate ligament and celiac plexus.

Celiac axis stenosis is frequently associated with pancreaticoduodenal artery aneurysms. Although the cause of stenosis was not clear in most of the reported cases, compression of the median arcuate ligament of the diaphragm was found to be responsible for the stenosis in 7 of 42 reported cases of this type of aneurysm. We report a case of aneurysm caused by compression of the median arcuate ligament of the diaphragm and celiac plexus. An asymptomatic 43-year-old Japanese man was admitted with a low echoic lesion in the uncus of pancreas. Computed tomographic scan and angiogram revealed stenosis of the celiac axis and two aneurysms in the inferior posterior pancreaticoduodenal artery. The celiac plexus and median arcuate ligament were divided surgically and normal flow was reestablished in the celiac axis. One of the aneurysms was resected and the afferent artery of the other aneurysm was ligated. In the setting of pancreaticoduodenal artery aneurysm associated with celiac axis stenosis, management of stenosis should be considered in addition to local treatment of the aneurysm. In this context, division of median arcuate ligament and celiac plexus or aorto-celiac bypass may normalize the flows in the pancreaticoduodenal arcade and could be effective in preventing aneurysm reformation.

Adult↗
PubMed1998

Steroid-refractory severe ulcerative colitis responding to cyclosporine and long-term follow-up.

We report a case of steroid-refractory ulcerative colitis, treated with cyclosporine, in a 38-year-old woman with a 13-year history of ulcerative colitis. No remission was achieved with treatments that included intravenous hyperalimentation, sulfasalazine, and intensive parenteral prednisolone therapy for 4 weeks. Intravenous infusion of cyclosporine was performed because the patient refused to undergo surgery. Her condition improved dramatically and colectomy was avoided. She has been maintained on oral cyclosporine and azathioprine since steroids were discontinued, and she has remained in clinical and endoscopic remission for 2 years. The side effects were not significant, but mild paresthesia in both hands and mild hypertension, which was controlled by anti-hypertensives. Cyclosporine seems to be an effective treatment for patients with steroid-refractory severe active ulcerative colitis in whom colectomy seems inevitable. We believe further clinical trials of the treatment are warranted.

Adult↗
PubMed1998

Consanguinity and the age of menopause in the United Arab Emirates.

OBJECTIVE: The study examined the association between some biosocial factors, consanguinity and age at natural menopause in the United Arab Emirates (UAE). METHOD: A cross-sectional population-based study using a multi-stage sampling design and face-to-face interview. RESULTS: In a sample of 800 UAE females aged 40 years and above, there were 742 (85.8%) respondents. The median age of natural menopause was 48 years. The bodyweight, parity number, occupation, smoking habits and consanguinity in marriage were the significant variables associated with the age at natural menopause. There were statistically significant differences between women in consanguineous and non-consanguineous marriages with regard to BMI (P < 0.002), occupation (P < 0.008), weight (P < 0.0001), age (P < 0.03), age of menopause (P < 0.005), parity (P < 0.0001), mother's age at menopause (P < 0.007) and sister's age at menopause (P < 0.002). CONCLUSION: The study showed that among UAE women, consanguinity of marriage, maternal and sister's age at menopause, BMI, parity number and smoking habits significantly influence the natural age of menopause.

Age of Onset↗
PubMed1998

Phosphoramidon, an inhibitor of endothelin-converting enzyme, prevents indomethacin-induced gastric mucosal damage in rats.

Endothelin-1 (ET-1) is produced from inactive precursor big ET-1 by endothelin-converting enzyme-1 (ECE-1), a membrane-bound metalloprotease, structurally similar to another metalloprotease, neutral endopeptidase 24.11 (NEP). Although both phosphoramidon and thiorphan are metalloprotease inhibitors, the ECE activity is inhibited by phosphoramidon but not by thiorphan, a specific inhibitor of NEP. Therefore, to investigate whether an ECE inhibitor can prevent indomethacin-induced gastric mucosal damage in rats, we compared the effects between the two metalloprotease inhibitors on both gastric mucosal integrity and the levels of ET-1 and big ET-1 in gastric tissue. Phosphoramidon significantly decreased ET-1 levels, causing a concomitant big ET-1 increase and dose-dependently attenuated indomethacin-induced gastric mucosal damage. By contrast, thiorphan neither changed the ratio of ET-1/big ET-1 nor attenuated the damage. In conclusion, the prevention of gastric mucosal damage by an ECE inhibitor indicates that endogenous ET-1 may play an important role in the pathogenesis of indomethacin-induced gastric mucosal damage.

Animals↗
PubMed1998

Liposomal busulphan: bioavailability and effect on bone marrow in mice.

High-dose busulphan is an important component of many BMT conditioning regimens. High-dose busulphan therapy is associated with an increased risk of acute toxicity such as CNS toxicity and veno-occlusive disease (VOD). The toxicity was reported to correlate with a high AUC (area under the curve) during therapy. An intravenous form of busulphan would overcome the problems caused by inter-individual variability and bioavailability of busulphan and most probably minimize the problems with dose adjustment during therapy. The liposomal form of busulphan is an attractive alternative for intravenous administration of busulphan. In the present study, we compared the myeloablative effect of liposomal busulphan (LB) with that of the oral administration form and busulphan dissolved in organic solvent (Bus/DMSO) in mice. The pharmacokinetics of LB and Bus/DMSO were described by one compartment model while the oral data were fitted to one compartment model with first order absorption. The bioavailability of LB was 0.86+/-0.02 compared to that obtained after the oral administration (0.40-0.74). Myelosuppression was determined using the colony-forming unit granulocyte-macrophage assay (CFU-GM) on days 1, 3, 6 and 9 after the conditioning regimen. LB resulted in significant myelosuppression from day 1 to day 9. The decrease in CFU-GM after conditioning regimen with LB was not significantly different from that observed after oral busulphan. Moreover, the administration of liposomes only to the mice did not affect the bone marrow. No side-effects of the liposomal formulation were observed. We suggest that the novel form of busulphan is a promising drug for clinical use.

Administration, Oral↗