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Biomedical subjects

M Ismail

Publications and source records attributed to M Ismail.

At least 19 recordsLinked to original sources

[Excimer laser extraction of pacemaker and defibrillator leads].

BACKGROUND: Pacemaker infection or some lead dysfunctions are an indication for removal of all foreign material. The use of laser energy is a new method for extraction of fixed leads that have been in place for a long time. There are only a few reports on results and complications of laser extraction in comparison to conventional methods. Therefore, this study compares results of laser lead extraction and conventional methods. METHODS: Since January 1999 we have made use of the laser lead extraction system of Spectranetics, Inc. Inner traction of the leads was performed using a "lead locking device" (LLD) and for laser application 12, 14 und 16 French "laser sheaths" were used. As the energy source, an excimer laser device was used (CVX-300). The intervention was performed under heart-lung machine backup. Results of the laser procedure in 24 patients and 45 leads (including 3 defibrillator leads) are compared to results of manual traction (23 patients, 53 leads), traction devices (24 patients, 38 leads), snare catheters (6 patients, 6 leads) and thoracotomy (5 patients, 9 leads) from the years 1995-1998. RESULTS: The mean operation time of the laser method (93 +/- 50 min) was not significantly different from manual traction (82 +/- 48 min,) or traction devices (100 +/- 45 min). The mean fluoroscopy time (9.4 +/- 50 min) was similar to traction devices (8.4 +/- 5 min, p < 0.05). In one patient a percardial tamponade developed with the need for urgent thoracotomy. This patient died on the fourth postoperative day due to cerebral hypoxia. The other 23 patients had an uneventful course. All but one lead could be removed without fragmentation, including a malpositioned lead in the left ventricle (success rate 96%). In 62 patients and 97 conventional extractions (53x manual, 38x device, 6x snare) from 1995-1998, one fatal (sepsis due to lead fragmentation) and four severe complications developed (pericardial tamponade, pulmonary abscess, pulmonary embolism, sepsis). In 15/62 patients with conventional methods, lead fragments remained (success rate 76%). Of five patients from 1995-1998, in whom leads with vegetations or tricuspid valve insufficiency were removed by thoracotomy and cardiopulmonary bypass, one patient died perioperatively. CONCLUSIONS: In contrast to conventional methods, excimer laser pacemaker or defibrillator lead extraction allows total removal of all foreign material. This prevents late complications from lead fragments left in place. However, life-threatening complications can occur with conventional as well as with the laser method. Therefore, this intervention should be done only in specialized centers using extended monitoring (invasive blood pressure, TEE).

Data Interpretation, Statistical↗

Association between funisitis and elevated interleukin-6 in cord blood.

OBJECTIVE: [corrected] To determine whether elevated plasma interleukin-6 (IL-6) in umbilical venous cord blood at delivery is associated with funisitis and whether IL-6 can be used to screen for funisitis in preterm neonates. METHODS: At the time of delivery, umbilical venous cord blood samples were collected from 92 infants for whom placental pathology results were also available. Interleukin-6 concentrations in the umbilical venous cord blood plasma were measured by immunoassay. Histologic examinations of the placenta and umbilical cord were done to determine the presence or absence of funisitis and chorioamnionitis. For a power of 90% with an alpha of.05, 12 subjects were required in each group. RESULTS: We found a significant association between the presence of histologic funisitis and elevated umbilical venous cord blood plasma IL-6 concentrations (defined as 10 pg/mL or greater). Of 15 infants whose umbilical cords showed funisitis, 93% (14 of 15) had elevated umbilical venous cord blood plasma IL-6 concentrations. Of 77 infants without funisitis, 32% (25 of 77) had elevated IL-6 concentrations in their cords (P <.001, two-sided Fisher exact test). The negative predictive value of IL-6 as a screening test for funisitis was 98%. CONCLUSION: In preterm neonates, screening for funisitis by using the immunoassay for IL-6 appears to be valid. In the near future, elevated umbilical venous cord blood IL-6 concentrations at delivery could be clinically useful to identify children who might benefit from early treatment for systemic fetal inflammatory syndrome.

Adult↗

Praziquantel-induced tegumental damage in vitro is diminished in schistosomes derived from praziquantel-resistant infections.

The aggressive use of praziquantel to combat schistosomiasis in Egpyt raises concern about the possible emergence of resistance. Eggs from Egyptian patients with praziquantel-resistant infections (not cured by 3 doses of praziquantel) have been used to establish infection-specific schistosome isolates in mice. The response of these worms to the drug was observed in vitro, in order to determine if the isolates obtained from these resistant infections were, in fact, less responsive to praziquantel. One of the hallmark effects of praziquantel on schistosomes in vitro is a disruption of the worm's outer surface, the tegument. Here, praziquantel-induced tegumental damage is observed in 3 distinct isolates, 2 derived from resistant infections and 1 from an infection cured by a single dose. The isolates from the resistant infections were less susceptible to praziquantel-induced tegumental damage in vitro, suggesting that the worms are in some way less responsive to the drug.

Animals↗

Bcl-2 and Bcl-x expression in the CD34+ cells of aplastic anaemia patients: relationship with increased apoptosis and upregulation of Fas antigen.

Aplastic anaemia (AA) is a syndrome of haemopoietic failure involving increased apoptosis in stem cells. AA CD34+ cells often have upregulated Fas antigen, but this does not explain the increased apoptosis in all patients. To examine whether abnormal expression of the apoptotic modulators Bcl-2 and Bcl-x is involved in increased apoptosis in the CD34+ cells of patients, we examined cells from 19 AA patients and 18 normal controls by triple staining for CD34, Bcl-2 or Bcl-x, together with 7-amino actinomycin D to determine viability or with staining for Fas antigen. We confirmed increased apoptosis of CD34+ cells in patients. All CD34+ cells in patients and controls expressed Bcl-2 and Bcl-x with no significant difference between the groups. In patients, viability of CD34+/Bcl-2hi cells was similar to that of CD34+/Bcl-2lo cells, but CD34+/Bcl-xhi cells were significantly more viable than CD34+/Bcl-xlo cells. CD34+ cells from AA patients expressed upregulated Fas antigen, but this did not correlate with Bcl-2 or Bcl-x expression. These results suggest a more significant role for Bcl-x as an anti-apoptotic regulator in CD34+ cells in AA than Bcl-2. The induction of death by Fas antigen may bypass the anti-apoptotic effect of Bcl-2 and Bcl-x in CD34+ cells in AA.

Adolescent↗

Correction of stromal cell defect after bone marrow transplantation in aplastic anaemia.

Defects in stromal cell function have been demonstrated in a number of aplastic anaemia (AA) patients. Here we have studied a patient with severe AA and abnormal stromal cell function who underwent bone marrow transplantation (BMT). The objective of this study was to investigate the timing and the mechanism of correction of the stromal defect after transplantation. The patient, a 25-year-old woman with severe AA, underwent BMT from her brother. BM was obtained from the patient on five occasions: 2 weeks pre BMT, and 3, 8, 16 and 21 months post BMT. Stromal cells were grown to confluence and recharged with purified CD34+ cells from normal donors. The support of such cells, as assessed by weekly colony-forming assay (CFU) of non-adherent cells, was compared with that of stromal layers grown from normal BM. A novel technique of combined fluorescence in situ hybridization (FISH) and immunocytochemistry was used to determine the origin of specific stromal cell types on cytospins of stroma post BMT. Stromal function was defective at 2 weeks pre BMT and at 3 months post BMT, but returned to normal at 8 and 16 months post BMT. At 21 months post BMT, stromal fibroblasts and endothelial cells were shown to be of recipient origin, and macrophages and T cells were of donor origin. We present here evidence in a case of severe AA for defective stromal function before BMT and delayed normalization of function after BMT. This correlated with engraftment of donor macrophages and T cells, but not fibroblasts and endothelial cells.

Adult↗

High-frequency (10-18 kHz) hearing thresholds: reliability, and effects of age and occupational noise exposure.

The objective was to investigate the reliability and effects of age and noise on high-frequency hearing thresholds. A cross-sectional study was used involving 187 exposed and 52 non-industrial noise-exposed subjects selected randomly from noise-exposed and non-industrial noise-exposed subjects, respectively. Each subject was tested with both conventional-frequency (0.25-8 kHz) and high-frequency (10-18 kHz) audiometry. Test-retest results showed that high-frequency audiometry (HFA) was as reliable as the conventional procedure. Although the inter-subject variation was large, the intra-subject variation was small, indicating that HFA can be used more reliably than the conventional procedure to monitor individual cases over time. Both the hearing threshold at high frequencies and the upper frequency limit deteriorated as a function of age and frequency. The exposed subjects had significantly higher hearing thresholds than the non-exposed subjects at all the high frequencies tested, the difference between the two groups being greatest at 14 kHz. Multivariate analysis indicated that age was the primary predictor and noise exposure the secondary predictor of hearing thresholds in a high frequency range (10-18 kHz). In contrast, multivariate analysis indicated the reverse order-noise exposure as the primary predictor, then age-for a conventional frequency range (0.25-8 kHz). The results of this study suggest that HFA might be used as an early indicator for noise-induced hearing loss and acoustic trauma rather than audiometry at a conventional frequency (4 kHz), particularly for younger groups.

Adolescent↗

Ultrasound for prostate imaging and biopsy.

Transrectal ultrasound guided systemic sextant needle biopsy of the prostate has been the procedure of choice for the diagnosis of prostate cancer. Several shortcomings of this procedure have been recognized and there is concern that it may represent an inadequate sampling of the prostate. Refinements include modifications of biopsy location and an increase in the number of cores obtained. Enhanced ultrasound techniques may improve the accuracy of prostate biopsy. In addition, research continues to develop prognostic factors derived from the core biopsy that may enhance the prediction of tumor biology. This paper provides a basic review of transrectal ultrasound diagnosis of prostate cancer with emphasis on advances in this area.

Biopsy, Needle↗

Nonvalue of the initial microbiological studies in the management of nonsevere community-acquired pneumonia.

STUDY OBJECTIVE: To assess the value of the initial microbiological studies (MBS), consisting of sputum Gram's stains, sputum cultures, and blood cultures, in the etiologic diagnosis of community-acquired pneumonia (CAP) without comorbidity. DESIGN: A prospective study of 74 adult patients hospitalized with nonsevere CAP empirically treated according to the American Thoracic Society guidelines (ATS-GL) and evaluated with Gram's stains and cultures of valid sputum specimens and blood cultures. SETTING: University-affiliated community hospital. RESULTS: Gram's stain of a valid sputum specimen failed to identify the etiologic agent in all patients. Sputum cultures identified pathogens in only four patients (5%). The results of all blood cultures were negative. All patients responded to the initial empiric antibiotic coverage selected according to the ATS-GL, and the results of the initial MBS had no clinical impact. CONCLUSION: The initial MBS, such as sputum Gram's stains, sputum cultures, and blood cultures, have no value in the management of nonsevere CAP without comorbid factors.

Adult↗

A new locus for autosomal recessive RP (RP29) mapping to chromosome 4q32-q34 in a Pakistani family.

PURPOSE: To map the disease locus in a six-generation, consanguineous Pakistani family with autosomal recessive retinitis pigmentosa (arRP). All affected individuals had pigmentary retinopathy associated with symptoms of night blindness and the loss of peripheral visual fields by the age of 20 years, loss of central vision between the ages of 25 and 30 years, and complete blindness between the ages of 40 and 50 years. METHODS: Genomic DNA from family members was typed for alleles at known polymorphic genetic markers using polymerase chain reaction. Alleles were assigned to individuals, which allowed calculation of LOD scores using the programs Cyrillic (http://www.cyrillicsoftware.com) and MLINK (Cherwell Scientific Publishing LTD:, Oxford, UK). The genes for membrane glycoprotein (M6a) and chloride channel 3 (CLCN3) were analyzed by direct sequencing for mutations. RESULTS: A new locus for arRP (RP29) has been mapped to chromosome 4q32-q34. A maximum two-point LOD score of 3.76 was obtained for the marker D4S415, with no recombination. Two recombination events in the pedigree positioned this locus to a region flanked by markers D4S621 and D4S2417. A putative region of homozygosity by descent was observed between the loci D4S3035 and D4S2417, giving a probable disease interval of 4.6 cM. Mutation screening of two candidate genes, M6a and CLCN3, revealed no disease-associated mutations. CONCLUSIONS: The results suggest that the arRP phenotype maps to a new locus and is due to a mutated gene within the 4q32-q34 chromosomal region.

Adult↗

Occupational noise exposure and hearing loss of workers in two plants in eastern Saudi Arabia.

OBJECTIVE: To determine the prevalence of hearing loss associated with occupational noise exposure and other risk factors. DESIGN: A cross-sectional study involving 269 exposed and 99 non-exposed subjects (non-industrial noise exposed subjects) randomly selected. Current noise exposure was estimated using both sound level meter and noise-dosimeter. Past noise exposure was estimated by interview questionnaire. Otoscopic examination and conventional frequency (0.25-8 kHz) audiometry were used to assess the hearing loss in each subject. RESULTS: 75% (202 subjects) from the exposed group were exposed to a daily Leq above the permissible level of 85 dB(A) and most (61%) of these did not and had never used any form of hearing protection. Hearing loss was found to be bilateral and symmetrical in both groups. Bivariate analysis showed a significant hearing loss in the exposed vs non-exposed subjects with a characteristic dip at 4 kHz. Thirty eight percent of exposed subjects had hearing impairment, which was an 8-fold higher rate than that found for non-exposed subjects. Multivariate analysis indicated exposure to noise was the primary, and age the secondary predictor of hearing loss. Odds of hearing impairment were lower for a small sub-group of exposed workers using hearing protection (N=19) in which logistic regression analysis showed the probability of workers adopting hearing protective devices increased with noise exposure, education, and awareness of noise control. Hearing loss was also greater amongst those who used headphones to listen to recorded cassettes. CONCLUSION: Gross occupational exposure to noise has been demonstrated to cause hearing loss and the authors believe that occupational hearing loss in Saudi Arabia is a widespread problem. Strategies of noise assessment and control are introduced which may help improve the work environment.

Adult↗

Locus for autosomal recessive nonsyndromic persistent hyperplastic primary vitreous.

PURPOSE: To map the disease locus in a six-generation, consanguineous Pakistani family affected by nonsyndromic autosomal recessive persistent hyperplastic primary vitreous (arPHPV). All affected individuals had peripheral anterior synechiae and corneal opacities with variable degrees of cataract and a retrolenticular white mass behind the lens. METHODS: Genomic DNA from family members was typed for alleles at more than 400 known polymorphic genetic markers, by polymerase chain reaction. Alleles were assigned to individuals, which allowed calculation of lod scores. RESULTS: A maximum two-point lod score of 4.07 was obtained with marker D10S1225 with no recombination. Two recombinations with marker D10S208 and D10S537 localized the disease within a region of approximately 30 centimorgans (cM). However, homozygosity across the region refined the arPHPV locus to 13 cM. CONCLUSIONS: Linkage analysis shows localization of nonsyndromic arPHPV to chromosome10q11-q21.

Adolescent↗

Chemical composition and antioxidant activity of Strobilanthes crispus leaf extract.

This study investigated the components present in and the total antioxidant activity of leaves of Strobilanthes crispus (L.) Bremek or Saricocalyx crispus (L.) Bremek (Acanthacea). Proximate analyses and total antioxidant activity using ferric thiocyanate and thiobarbituric acid methods were employed. Minerals content was determined using the atomic absorption spectrophotometer, whereas the water-soluble vitamins were determined by means of the UV-VIS spectrophotometer (vitamin C) and fluorimeter (vitamins B(1) and B(2)). Catechin, tannin, caffeine, and alkaloid contents were also studied. All data were compared to the previously reported results of Yerbamate, green tea, black tea, and Indian tea. The dried leaves contained a high amount of total ash (21.6%) as a result of a high amount of minerals including potassium (51%), calcium (24%), sodium (13%), iron (1%), and phosphorus (1%). High content of water-soluble vitamins (C, B(1), and B(2)) contributed to the high antioxidant activity of the leaves. The leaves also contained a moderate amount of other proximate composition as well as other compounds such as catechins, alkaloids, caffeine, and tannin, contributing further to the total antioxidant activity. Catechins of Strobilanthes crispus leaves showed highest antioxidant activity when compared to Yerbamate and vitamin E. Consumption of the leafy extract daily (5 g/day) as an herbal tea could contribute to the additional nutrients and antioxidants needed in the body to enhance the defense system, especially toward the incidence of degenerative diseases.

Journal Article↗

A novel locus for Leber congenital amaurosis (LCA4) with anterior keratoconus mapping to chromosome 17p13.

PURPOSE: A two-generation consanguineous Pakistani family with autosomal recessive Leber congenital amaurosis (LCA, MIM 204,000) and keratoconus was identified. All affected individuals have bilateral keratoconus and congenital pigmentary retinopathy. The goal of this study was to link the disease phenotype in this family. METHODS: Genomic DNA was amplified across the polymorphic microsatellite poly-CA regions identified by markers. Polymerase chain reaction (PCR) products were separated by nondenaturing polyacrylamide gel electrophoresis. Alleles were assigned to individuals, which allowed calculation of LOD scores using the Cyrillic and MLINK software program. The retinal guanylate cyclase (RETGC-1, GDB symbol GUC2D) and pigment epithelium-derived factor (PEDF) genes were analyzed by heteroduplex analysis and direct sequencing for mutations in diseased individuals. RESULTS: Based on a whole genome linkage analysis the first locus for this combined phenotype has been mapped to chromosome 17p13. Linkage analysis gave a two point LOD score of 3.21 for marker D17S829. Surrounding this marker is a region of homozygosity of 15.77 cM, between the markers D17S1866 and D17S960; however, the crossover for the marker D17S1529 refines the region to 10.77 cM within which the disease gene is predicted to lie. Mutation screening of the nearby RETGC-1 gene, which has been shown to be associated with LCA1, revealed no mutations in the affected individuals of this family. Similarly, another prime candidate in the region PEDF was also screened for mutations. The factor has been shown to be involved in the photoreceptor differentiation and neuronal survival. No mutations were found in this gene either. Furthermore, RETGC-1 was physically excluded from the critical disease region based on the existing physical map. CONCLUSIONS: It is therefore suggested that this combined phenotype maps to a new locus and is due to an as yet uncharacterized gene within the 17p13 chromosomal region.

Blindness↗

Novel locus for autosomal recessive cone-rod dystrophy CORD8 mapping to chromosome 1q12-Q24.

PURPOSE: To map the disease locus of a two-generation, consanguineous Pakistani family with autosomal recessive cone-rod dystrophy (arCRD). All affected individuals had night blindness, deterioration of central vision, photophobia, epiphora in bright light, and problems with color distinction. Fundoscopy revealed marked macular degeneration and attenuation of retinal vessels. Mild pigmentary changes were present in the periphery. METHODS: Genomic DNA was amplified across the polymorphic microsatellite poly-CA regions identified by markers. Alleles were assigned to individuals that allowed calculation of LOD scores using the Cyrillic (Cherwell Scientific, Oxford, UK) and MLINK (accessed from ftp://linkage. rockefeller.edu/softeware/linkage/) software programs. The cellular retinoic acid-binding protein 2 (CRABP2), cone transducin alpha-subunit (GNAT2), potassium inwardly rectifying channel, subfamily J, member 10 (KCNJ10), genes were analyzed by heteroduplex analysis and direct sequencing for mutations. RESULTS: A new locus for arCRD (CORD8) has been mapped to chromosome 1q12-q24. A maximum two-point LOD score of 4.22 was obtained with marker D1S2635 at recombination fraction of theta = 0.00. Two critical recombinations in the pedigree positioned this locus to a region flanked by markers D1S457 and D1S2681. A region of homozygosity was observed within the loci D1S442 and D1S2681, giving a probable critical disease interval of 21 cM. Mutation screening of the three candidate genes CRABP2, GNAT2, and KCNJ10 revealed no disease-associated mutations. CONCLUSIONS: The findings therefore suggest that this phenotype maps to a new locus and is due to an as yet uncharacterized gene within the 1q12-q24 chromosomal region.

Adolescent↗