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Biomedical subjects

M Haider

Publications and source records attributed to M Haider.

At least 19 recordsLinked to original sources
PubMed2007

Effects of prior endoluminal gastroplication on subsequent laparoscopic Nissen fundoplication.

BACKGROUND: The long-term results of endoluminal gastroplication (ELGP) for gastroesophageal reflux disease (GERD) are still under investigation. Laparoscopic Nissen fundoplication (LNF) has unquestionable results in the treatment of GERD and, therefore, it would be unfortunate to compromise this treatment option by performing alternative therapies such as ELGP. METHODS: Six patients underwent ELGP for the treatment of GERD symptoms. After symptoms returned, these patients elected to have a LNF. RESULTS: There was no sign of periesophagitis or intraperitoneal adhesion formation found at hiatal dissection that hindered or complicated the LNF procedure. Recent follow-up has shown that the patient's GERD symptom scores have decreased, as expected after a de novo LNF. CONCLUSION: ELGP does not alter the surgical dissection or results of a subsequent LNF.

Adult↗
PubMed2006

Technique and follow-up of minimally invasive Heller myotomy for achalasia.

BACKGROUND: Laparoscopic Heller myotomy has been proven effective. Reliable predictive factors for outcome and the true benefit of the da Vinci robotic system, however, remain unknown. METHODS: Seventy patients underwent laparoscopic Heller myotomy. The number of intraoperative perforations and the symptom-predictive value of postoperative esophagogram width measurement at the gastroesophageal junction were analyzed. RESULTS: The overall complication rate was 11%. Four patients experienced intraoperative perforation during the laparoscopic technique. No perforations were experienced with the da Vinci robotic system (n = 19). Of the total, 82% of patients had resolution of dysphagia, 91% of regurgitation, 91% of heartburn and 82% of chest pain. Immediate postoperative esophagogram gastroesophageal junction width demonstrated a positive predictive trend from 0 to 10 mm for dysphagia. CONCLUSION: Laparoscopic Heller myotomy is an effective treatment for achalasia. Immediate postoperative esophagogram gastroesophageal junction width measurement as a predictor for symptom resolution requires further study.

Adolescent↗
PubMed2006

Laparoscopic re-operation for failed Heller myotomy.

Laparoscopic Heller myotomy for achalasia has a 10-20% failure rate and may require re-operation to control persistent or recurrent symptoms. We report follow-up of 15 patients who underwent laparoscopic re-operation for failed Heller myotomy. Between 1993 and 2004, 15 patients underwent laparoscopic re-operation for failed Heller myotomy at our center. The mean duration between procedures was 23 months. Follow-up was completed at a mean duration of 30 months in 14 patients (93%) via a telephone questionnaire. Our overall failure rate for primary surgery (n = 106) was 5.6%. The mechanisms of failure were incomplete myotomy (33%), myotomy fibrosis (27%), fundoplication disruption (13%), too tight fundoplication (7%) and a combination of myotomy fibrosis and incomplete myotomy (20%). Significant symptom improvement was observed with postoperative symptom resolution seen in 71% of patients with dysphagia, 89% for regurgitation, 58% for heartburn and 40% for chest pain. Fifty percent reported excellent results and 79% would recommend the procedure to a friend. Subsequent dilations were performed in four patients (29%). Two patients required conversion to open surgery (13%). Three patients (20%) failed the re-operation and required further revisional surgery. Complications included intraoperative perforation in three (none of which resulted in postoperative morbidity) and a pneumothorax in one patient. Prior endoscopic therapies (pneumatic dilation or Botulinum toxin) were not associated with poor results. Laparoscopic re-operation for failed Heller myotomy is feasible and results are encouraging.

Adolescent↗
PubMed2005

Recombinant polymers for cancer gene therapy: a minireview.

A major challenge for successful cancer gene therapy is the development of safe and effective gene delivery vectors. Gene delivery vectors can be viral or nonviral. Among nonviral vectors various polymeric vectors have shown potential in gene delivery. However, much work needs to be done in order to correlate polymer structure with gene release at the target site and transfection efficiency. This article is a brief introduction into cancer gene therapy, barriers and methods for gene transfer with emphasis on the applications of recombinant polymers for cancer gene therapy.

Amino Acid Sequence↗
PubMed2005

Alpha-2-globin gene polyadenylation (AATAAA-->AATAAG) mutation in hemoglobin H disease among Kuwaitis.

OBJECTIVES: In the Arabian Gulf region, hemoglobin (Hb) H disease usually results from homozygosity or compound heterozygosity involving the alpha2-globin gene polyadenylation (poly A) signal (AATAAA-->AATAAG) mutation (alpha(T)alpha). Here we document the clinical and hemato logical characteristics of children with Hb H disease being followed in Kuwait. SUBJECTS AND METHODS: Twenty-four patients (0.5-12 years old, mean 4.7 +/- 3.5 years) with persistent microcytic, hypochromic anemia (and normal iron status as well as normal Hb A2 levels) were referred to the pediatric hematology clinic for further investigations. They were all screened for the alpha+-thalassemia (alpha+-thal; -3.7 kb) deletion using a standard PCR method. They were also screened for the alpha2-globin gene alpha(T)alpha allele and the 5nt deletion (-alpha5nt) in the first intervening sequence, which are common alpha-thal alleles in this population. They were followed up for periods ranging from 2 to 8 years. RESULTS: Of the 24 patients, 4 (16.7%) also had sickle cell trait (Hb-AS), while 7 (29.2%) were glucose-6-phosphate dehydrogenase deficient. Only 1 patient had significant hepatosplenomegaly and 1 developed gallstones. While none was on chronic transfusion therapy, 8 (33.3%) had been transfused at least once and, in 3 instances, this was secondary to parvovirus B19 +ve aplastic crisis. The alpha-globin genotype was successfully determined in almost all patients. The results showed that 17 (70.8%) patients were homozygous for the poly A mutation (alpha(T)alpha/alpha(T)alpha), 6 (25.0%) were compound heterozygotes for this and the alpha+-thal (-3.7 kb) deletion (-alpha/alpha(T)alpha) and 1 (4.2%) was undetermined. There were no significant differences in the phenotypes of the 2 genotypes and their hematological features were identical. CONCLUSIONS: Hb H disease involving the poly A mutation is a mild thal intermedia phenotype among Kuwaitis. There are no serious complications and there is no need for regular blood transfusion.

Child↗
PubMed2003

Magnetic resonance imaging in the radiation treatment planning of localized prostate cancer using intra-prostatic fiducial markers for computed tomography co-registration.

PURPOSE: To assess the feasibility, and potential implications, of using intra-prostatic fiducial markers, rather than bony landmarks, for the co-registration of computed tomography (CT) and magnetic resonance (MR) images in the radiation treatment planning of localized prostate cancer. METHODS: All men treated with conformal therapy for localized prostate cancer underwent routine pre-treatment insertion of prostatic fiducial markers to assist with gross target volume (GTV) delineation and to identify prostate positioning during therapy. Six of these men were selected for investigation. Phantom MRI measurements were obtained to quantify image distortion, to determine the most suitable gold alloy marker composition, and to identify the spin-echo sequences that optimized both marker identification and the contrast between the prostate and the surrounding tissues. The GTV for each patient was contoured independently by three radiation oncologists on axial planning CT slices, and on axial MRI slices fused to the CT slices by matching the implanted fiducial markers. From each set of contours the scan common volume (SCV), and the scan encompassing volume (SEV), were obtained. The ratio SEV/SCV for a given scan is a measure of inter-observer variation in contouring. For each of the 18 patient-observer combinations the observer common volume (OCV) and the observer encompassing volume (OEV) was obtained. The ratio OEV/OCV for a given patient-observer combination is a measure of the inter-modality variation in contouring. The distance from the treatment planning isocenter to the prostate contours was measured and the discrepancy between the CT- and the MR-defined contour recorded. The discrepancies between the CT- and MR-defined contours of the posterior prostate were recorded in the sagittal plane at 1-cm intervals above and below the isocenter. RESULTS: Phantom measurements demonstrated trivial image distortion within the required field of view, and an 18K Au/Cu alloy to be the marker composition most suitable for CT-MRI image fusion purposes. Inter-observer variation in prostate contouring was significantly less for MR compared to CT. The mean SEV/SCV ratio was 1.58 (confidence interval (CI): 1.47-1.69) for CT scans and 1.37 (CI: 1.33-1.41) for MR scans (paired t-test; P=0.036). The overall magnitude of contoured GTV was similar for MR and CT; however, there were spatial discrepancies in contouring between the two modalities. The greatest systematic discrepancy was at the posterior apical prostate border, which was defined 3.6 mm (SD 3.5 mm) more posterior on MR- than CT-defined contouring. CONCLUSIONS: Prostate contouring on MR is associated with less inter-observer variation than on CT. In addition, we have demonstrated the feasibility of using intra-prostatic fiducial markers, rather than bony landmarks, for the co-registration of CT and MR images in the radiation treatment planning of localized prostate cancer. This technique, together with on-line correction of treatment set-up according to the fiducial marker position on electronic portal imaging, may enable a reduction in the planning target volume (PTV) margin needed to account for inter-observer error in target delineation, and for prostate motion.

Biomarkers↗
PubMed2002

Laser therapy of freckles and lentigines with quasi-continuous, frequency-doubled, Nd:YAG (532 nm) laser in Fitzpatrick skin type IV: a 24-month follow-up.

BACKGROUND: Newly developed lasers produce excellent results with minimal complications compared with traditional treatments for freckles and lentigines. OBJECTIVES: To assess the efficacy and safety of the frequency-doubled Nd:YAG (532 nm) laser in the treatment of freckles and lentigines in type IV skin. PATIENTS AND METHODS: Twenty adult patients (14 with freckles and six with lentigines) were subjected to a variable number of treatments with a minimum 4-week interval until no additional improvement occurred or > 75% improvement was obvious. Patients manifesting > 50% improvement were followed up once every 3 months for 24 months. The rest were regarded as treatment failures and not followed up. RESULTS: Sixteen (80%) of 20. patients (freckles, n = 10; lentigines, n = 6) manifested more than 50% improvement. They were treat- irradiated between three and eight times with a 4-12-week interval. Complications included hypopigmentation (25%), mild textural changes (15%) and hyperpigmentation (10%). All these were mild and resolved within 2-6 months. Of 10 patients with freckles followed up for 24 months, four (40%) patients showed partial recurrence. However, all the patients maintained > 50% improvement. None of the patients with lentigines showed recurrence. CONCLUSION: The quasi-continuous, frequency-doubled Nd:Y AG (532 nm) laser safely and effectively treats freckles and lentigines in Fitzpatrick skin type IV.

Adult↗
PubMed2001

The inclusion of capillary distribution in the adiabatic tissue homogeneity model of blood flow.

We have developed a non-invasive imaging tracer kinetic model for blood flow which takes into account the distribution of capillaries in tissue. Each individual capillary is assumed to follow the adiabatic tissue homogeneity model. The main strength of our new model is in its ability to quantify the functional distribution of capillaries by the standard deviation in the time taken by blood to pass through the tissue. We have applied our model to the human prostate and have tested two different types of distribution functions. Both distribution functions yielded very similar predictions for the various model parameters, and in particular for the standard deviation in transit time. Our motivation for developing this model is the fact that the capillary distribution in cancerous tissue is drastically different from in normal tissue. We believe that there is great potential for our model to be used as a prognostic tool in cancer treatment. For example, an accurate knowledge of the distribution in transit times might result in an accurate estimate of the degree of tumour hypoxia, which is crucial to the success of radiation therapy.

Capillaries↗
PubMed2000

Upper limits for the residual aberrations of a high-resolution aberration-corrected STEM

The development of correctors for electron optical systems has already brought the improvement of resolution for a low-voltage scanning electron microscope and a commercially available transmission electron microscope and is anticipated in the near future for a dedicated scanning transmission electron microscope (STEM). The resolution attainable especially of a probe-forming system at 200 kV cannot only be estimated from calculations ignoring all non-rotationally symmetric axial aberrations in an electron optical system. For a certain resolution, one would like to attain, the influence of the deviations from the ideal, aberration-free system has to be investigated. Therefore, in the following we have carried out the evaluation of the required accuracy for the compensation of the various residual aberrations in order to achieve a resolution in the sub-Angstrom regime with a probe-forming system.

Journal Article↗
PubMed2000

Flow-cytometry-enhanced fine-needle aspiration biopsy of the spleen.

OBJECTIVE: Flow cytometry is proving useful in the evaluation of lymphoproliferative disorders. In a case series, the authors investigated the safety of cross-sectional fine-needle aspiration biopsy of the spleen under sonographic guidance, and the usefulness of flow cytometry in analysis of biopsy samples. METHODS: Five patients underwent fine-needle biopsy with freehand sonographic guidance. Samples were analyzed on a flow cytometer. RESULTS: Through cytologic examination enhanced by flow cytometry, 2 cases of lymphoma, 1 case of metastatic transitional cell carcinoma, and 1 case of focal splenic hemangioma were diagnosed. Normal lymphocytes were demonstrated in 1 case, in which long-term follow-up of splenomegaly showed that this was related to cirrhosis and portal hypertension in a patient with a history of treated non-Hodgkin's lymphoma. CONCLUSION: Flow-cytometry-enhanced fine-needle aspiration of the spleen is a safe and useful tool for the interventional radiologist. In our institution, it evolved as the result of effective teamwork between diagnostic radiologists and pathologists. Flow cytometry promises to be increasingly useful in the diagnosis and management of lymphoproliferative diseases.

Aged↗
PubMed1999

Heterologous expression, purification, and kinetic comparison of the cytoplasmic and mitochondrial glyoxalase II enzymes, Glo2p and Glo4p, from Saccharomyces cerevisiae.

The aims of the present study are (i) to purify a mitochondrial glyoxalase II to homogeneity for the first time from any organism and (ii) to compare its kinetic properties with those of the cytoplasmic enzyme. Both the cytoplasmic and the mitochondrial glyoxalases II from Saccharomyces cerevisiae, which are the products of two distinct genes, GLO2 and GLO4, were purified from yeast and in recombinant form from Escherichia coli. To obtain a higher protein yield (compared to wild-type expression) in yeast, the genes were placed under the control of the strong GAL1 promoter on a multicopy plasmid. Amino-terminal sequencing and molecular mass determination by MALDI-TOF mass spectrometry of the mitochondrial Glo4 protein revealed Met-11 of the primary translation product of the gene as the N-terminal amino acid. Judged by enzyme kinetic properties the recombinant and natural proteins were equivalent. The cytoplasmic and the mitochondrial enzyme differed in the pH dependence of the kinetic parameters for the main substrate, S-d-lactoylglutathione. Whereas the cytoplasmic protein showed a pronounced peak of enzyme activity between pH 7-8 and a continuous up to fivefold increase of the K(M) value with increasing pH (from 5. 5-9.0), the mitochondrial protein had a nearly constant K(M) value and an activity maximum over a broad pH range (6.5-9.0). The kinetic parameters (at pH 7.5) of both the cytoplasmic and the mitochondrial enzyme for S-D-lactoylglutathione were of the same order of magnitude as reported recently for the human and Arabidopsis thaliana enzymes which are presumably of cytoplasmic origin. However, both yeast enzymes showed a severalfold lower preference for the more hydrophobic substrate, S-d-mandeloylglutathione.

Cytoplasm↗
PubMed1999

A study on the effects of some new derivatives of piperidine on neurotransmitters.

Four chemically synthesized derivatives of piperidine were subjected to evaluate their pharmacological actions on Nervous System in male albino mice. The effects on neuro-transmitters such as catecholamine and indolamine assuming that these derivatives might alter them differently, studied by HPLC-EC method. The result revealed that brain dopamine and catecholamine were altered by most of these derivatives at the doses of 100 mg/kg body weight.

Journal Article↗
PubMed1998

Antibacterial activity of Camellia sinensis extracts against dental caries.

Different bacteria were separated from saliva and teeth of cariogenic patients and identified by a variety of morphological and biochemical tests. Extracts of green tea strongly inhibited Escherichia coli, Streptococcus salivarius and Streptococcus mutans. The antibacterial effect of green and black tea extracts were compared with those of amoxicillin, cephradine and eugenol.

Adolescent↗