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Biomedical subjects

Z Hussain

Publications and source records attributed to Z Hussain.

At least 55 records · Page 3Linked to original sources
PubMed2001

Use of glyceryl trinitrate patches in patients with ureteral stones: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: To report a randomized, double-blind, placebo-controlled trial of glyceryl trinitrate (GTN) patches. The primary outcome measure was stone passage at 6 weeks. GTN is a potent smooth muscle relaxant that may offer benefit by both reducing pain and facilitating ureteral stone passage. METHODS: Fifty consecutive patients, with a single radiopaque calculus less than 10 mm, were randomized to receive a 6-week course of patches containing either 5 mg GTN or placebo. Patients used a diary to record pain episodes during the 6-week study period and were reviewed weekly with x-ray imaging. Analysis was by intention to treat. RESULTS: Twenty-six patients were randomized to the GTN group and 24 to the placebo group. Seven patients in the GTN group discontinued therapy because of headaches. One patient in the placebo group discontinued because of a skin reaction to the patches. No serious adverse events were recorded. No difference was observed in the stone-free rate at 6 weeks (18 patients in each group), interval to stone passage (median GTN 11.5 days versus placebo 13 days), or interventions performed (5 patients each). Although the GTN group reported fewer pain episodes (median 3.5 versus 6.0), this did not achieve statistical significance. CONCLUSIONS: Our preliminary results did not demonstrate a significant advantage in using GTN compared with placebo, with regard to the stone-free rate at 6 weeks, interval to stone passage, or number of episodes of pain experienced.

Administration, Cutaneous↗
PubMed2001

Comparison of PCR to histology for the diagnosis of invasive candidiasis in a murine model.

The ability of a PCR method to diagnose invasive candidiasis in comparison to histology was determined using a murine model. One hundred and sixty mice were divided into 16 groups of 10 mice each. One group served as a negative control while 15 groups were infected with Candida albicans. Of the infected groups, 14 (A1-A7 and B1-B7) received fluconazole treatment. Surviving animals of group A1 were killed on day 3, and animals of successive groups were sacrificed every other day thereafter. Fluconazole treatment was stopped in the corresponding B group. All surviving mice were killed on day 43. One hundred and thirty-eight mice were evaluable. Yeast were seen in the kidney specimens of 77 mice; 66/77 of these, plus an additional 7 histologically-negative mice, were positive by PCR. The sensitivity and specificity of the PCR test compared with histology were 85.71% and 88.52%, respectively. In combination with blood cultures, PCR could be a useful diagnostic tool for invasive candidiasis in clinical settings.

Animals↗
PubMed2001

Evaluation of the Candigen enzyme-linked immunosorbent assay for quantitative detection of Candida species antigen.

OBJECTIVE: To assess the clinical utility of an enzyme-linked immunosorbent assay method for the quantitative detection of Candida species antigen (Candigen; Biomerica Inc, Newport Beach, Calif) in patients with suspected disseminated candidiasis. METHODS: Specimens of blood or cerebrospinal fluid from 75 patients with suspected disseminated candidiasis were analyzed by the Candigen test. Results were compared with those obtained by culture and polymerase chain reaction (PCR) analysis. RESULTS: Thirty-seven patients had specimens positive for Candida species by either culture or PCR. Of these specimens, 4 were positive by both culture and PCR, 21 were culture positive but PCR negative, and 12 were PCR positive but culture negative. Five specimens were positive by the Candigen test, all of which were PCR positive but culture negative. The sensitivity, specificity, and positive and negative predictive values of the Candigen test compared to culture plus PCR were 13.5%, 100%, 100%, and 54.3%, respectively. Turnaround time for the Candigen test was approximately 3 hours. CONCLUSION: The Candigen test showed excellent specificity and turnaround time, but its poor sensitivity coupled with its inability to provide species information or susceptibility data make its clinical utility questionable.

Adolescent↗
PubMed2001

Blastomyces dermatitidis with large yeast forms.

Yeast forms of Blastomyces dermatitidis typically range from 8 to 20 microm in largest diameter. We report a rare case of primary pulmonary blastomycosis with an unusual morphology, in which we found significant numbers of large yeast forms ranging from 30 to 35 microm in diameter. To our knowledge, this is only the second reported case of giant forms of B dermatitidis. We also review the literature and discuss the possible association of this unusual morphology with immunosuppression in general and glucocorticoid use in particular.

Aged↗
PubMed2001

A comparison of 1.5% glycine and 2.7% sorbitol-0.5% mannitol irrigants during transurethral prostate resection.

PURPOSE: We performed a prospective randomized trial comparing glycine 1.5% with 2.7% sorbitol-0.5% mannitol irrigating solution. We evaluated blood loss, fluid absorption, temperature change, cardiac effects and postoperative symptoms. MATERIALS AND METHODS: Between April 1998 and July 1999, 205 treated patients were included in the statistical analysis. Intraoperative irrigating fluid absorption was measured with the patient on the operating table. Serum cardiac troponin I was used as a marker of perioperative myocardial damage. Operative details were recorded, including the type of anesthesia, resection time and the weight of resected tissue. Postoperative symptoms were documented prospectively. RESULTS: Mean patient age was not significantly different in the glycine and sorbitol-mannitol groups. (72.1 versus 73.7 years). American Society of Anesthesiologists grade was also comparable. Median resection time was 27 minutes and resected tissue weighed a mean of 21 gm. The median resection rate was 0.8 gm. per minute. Blood loss and temperature changes during resection were similar in the 2 groups. Overall median blood loss was 216 ml. and irrigant absorption was 140 ml. In the sorbitol-mannitol group significantly less fluid was apparently absorbed during resection (median 88.2 versus 184.4 ml.). Analysis of the incidence of symptoms of the transurethral prostate resection syndrome did not show any differences in the irrigant groups. Cardiac damage measured using troponin I also showed no significant difference in the 2 groups, although there was a high overall incidence of 7.5%. CONCLUSIONS: We noted no significant differences in 1.5% glycine and 2.7% sorbitol-0.5% mannitol as an irrigating solution for transurethral prostate resection.

Aged↗
PubMed2000

Evidence for an energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8

Quasiparticle dispersion in Bi2Sr2CaCu2O8 is investigated with improved angular resolution as a function of temperature and doping. Unlike the linear dispersion predicted by the band calculation, the data show a sharp break in dispersion at 50+/-15 meV binding energy where the velocity changes by a factor of 2 or more. This change provides an energy scale in the quasiparticle self-energy. This break in dispersion is evident at and away from the d-wave node line, but the magnitude of the dispersion change decreases with temperature and with increasing doping.

Journal Article↗
PubMed2000

Two heme-binding domains of heme-regulated eukaryotic initiation factor-2alpha kinase. N terminus and kinase insertion.

In heme deficiency, protein synthesis in reticulocytes is inhibited by activation of heme-regulated alpha-subunit of eukaryotic initiation factor-2alpha (eIF-2alpha) kinase (HRI). Previous studies indicate that HRI contains two distinct heme-binding sites per HRI monomer. To study the role of the N terminus in the heme regulation of HRI, two N-terminally truncated mutants, Met2 and Met3 (deletion of the first 103 and 130 amino acids, respectively), were prepared. Met2 and Met3 underwent autophosphorylation and phosphorylated eIF-2alpha with a specific activity of approximately 50% of that of the wild type HRI. These mutants were significantly less sensitive to heme regulation both in vivo and in vitro. In addition, the heme contents of purified Met2 and Met3 HRI were less than 5% of that of the wild type HRI. These results indicated that the N terminus was important but was not the only domain involved in the heme-binding and heme regulation of HRI. Heme binding of the individual HRI domains showed that both N terminus and kinase insertion were able to bind hemin, whereas the C terminus and the catalytic domains were not. Thus, both the N terminus and the kinase insertion, which are unique to HRI, are involved in the heme binding and the heme regulation of HRI.

Cloning, Molecular↗
PubMed2000

Effect of hyperoxia on vascular endothelial growth factor levels in a wound model.

HYPOTHESIS: Hyperbaric oxygen (HBO) therapy increases vascular endothelial growth factor (VEGF) levels in wounds. DESIGN: Wounds were monitored for oxygen delivery during HBO treatment, and wound fluids were analyzed for VEGF and lactate on days 2, 5, and 10 following wounding. SETTING: Experimental animal model. INTERVENTIONS: Rats were randomized to HBO therapy and control groups. The HBO therapy was administered for 90 minutes, twice daily with 100% oxygen at 2.1 atmospheres absolute. Treatment was administered for 7 days following wounding. MAIN OUTCOME MEASURES: Vascular endothelial growth factor, PO(2), and lactate levels in wound fluid were measured on days 2, 5, and 10. RESULTS: Wound oxygen rises with HBO from nearly 0 mm Hg to as high as 600 mm Hg. The peak level occurs at the end of the 90-minute treatment, and hyperoxia of lessening degree persists for approximately 1 hour. The VEGF levels significantly increase with HBO by approximately 40% 5 days following wounding and decrease to control levels 3 days after exposures are stopped. Wound lactate levels remain unchanged with HBO treatment (range, 2.0-10.5 mmol/L). CONCLUSIONS: Increased VEGF production seems to explain in part the angiogenic action of HBO. This supports other data that hypoxia is not necessarily a requirement for wound VEGF production.

Animals↗
PubMed2000

Hospital- and community-based surveillance of methicillin-resistant Staphylococcus aureus: previous hospitalization is the major risk factor.

OBJECTIVE: The purpose of the study was to determine the incidence and risk factors for the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in our community. DESIGN: This study used a cross-sectional design to assess patients colonized or infected with MRSA. PATIENTS: The study population consisted of residents of London, Ontario, Canada, who were identified as MRSA-positive for the first time in 1997. SETTING: All acute- and chronic-care hospitals, long-term healthcare facilities, and community physicians' offices in the city of London participated in the study. MAIN OUTCOME MEASURE: Incidence of MRSA in the community, risk factors for acquisition, especially previous hospitalization over a defined period, and strain type were evaluated. RESULTS: In 1997, 331 residents of London were newly identified as MRSA-positive, representing an annual incidence of 100/100,000 persons (95% confidence interval, 88.8-110.7). Thirty-one (9.4%) individuals were not healthcare-facility patients in the previous month, and 11 (3.3%), 10 (3.0%), and 6 (1.8%) individuals had no such contact in the previous 3, 6, and 12 months, respectively. One hundred seventy-seven strains, including five of the isolates from patients with no healthcare-facility contact in the previous year, were typed. One hundred sixty (90.3%) of these isolates, including all typed strains from patients with no healthcare facility contact, belonged to a single clone. CONCLUSION: These findings demonstrate that the incidence of MRSA is higher than previously reported and that hospital contact is the single most important risk factor for the acquisition of MRSA in our community. Screening for MRSA in previously hospitalized patients at the time of hospitalization may reduce nosocomial spread and indirectly reduce the incidence of MRSA in the community.

Adult↗
PubMed2000

Correlation of oxacillin MIC with mecA gene carriage in coagulase-negative staphylococci.

The National Committee for Clinical Laboratory Standards has recently changed the oxacillin breakpoint from >/=4 mg/liter to >/=0. 5 mg/liter to detect methicillin-resistant coagulase-negative staphylococci (CoNS) because the previous breakpoint lacked sensitivity. To determine the correlation between the new oxacillin breakpoint and the presence of the mecA gene, 493 CoNS of 11 species were tested. The presence of the mecA gene was determined by PCR, and oxacillin susceptibility was determined by the agar dilution method with Mueller-Hinton agar containing 2% NaCl and oxacillin (0. 125 to 4.0 mg/liter). The new breakpoint correctly classified all CoNS strains with mecA as methicillin resistant and strains of Staphylococcus epidermidis, S. haemolyticus, and S. hominis without mecA as methicillin susceptible. The breakpoint of >/=0.5 mg/liter was not specific for S. cohnii, S. lugdunensis, S. saprophyticus, S. warneri, and S. xylosus, in that it categorized 70 of 74 strains of these species without mecA (94.6%) as methicillin resistant. The results of this study indicate that the new oxacillin breakpoint accurately identifies strains of CoNS with mecA but is not specific for strains of certain species of CoNS without mecA.

Coagulase↗
PubMed2000

Rapid detection of mecA-positive and mecA-negative coagulase-negative staphylococci by an anti-penicillin binding protein 2a slide latex agglutination test.

A rapid slide latex agglutination (LA) test, MRSA-Screen (Denka Seiken Co., Niigata, Japan), which detects PBP 2a, was tested for its ability to differentiate between mecA-positive and -negative coagulase-negative staphylococci. A total of 463 isolates from 13 species were included in the study. The mecA gene was detected by PCR, and the oxacillin MIC was determined by the agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS). The LA test was performed with oxacillin-induced isolates. The true-positive and true-negative results were defined on the basis of the presence or the absence of the mecA gene. By PCR, 251 isolates were mecA positive and 212 were mecA negative. The sensitivities, specificities, and positive and negative predictive values for the LA test compared to the NCCLS breakpoint for oxacillin resistance (>/=0.5 mg/liter) were as follows: for the LA test, 100, 99.5, 99.6, and 100%, respectively; for the NCCLS breakpoint, 100, 60.8, 75.1, and 100%, respectively. One hundred twenty-five mecA-positive isolates were also tested by the LA test without induction of PBP 2a; only 72 (57.6%) gave a positive result and required 3 to 15 min for reaction. With induction, all 251 isolates were positive within 3 min. The LA test was reliable in classifying mecA-negative isolates, but it classified isolates for which the oxacillin MIC was >/=0.5 mg/liter as oxacillin susceptible. For the reliable detection of oxacillin resistance by the MRSA-Screen in coagulase-negative staphylococci, induction of the mecA gene appears to be necessary.

Bacterial Proteins↗
PubMed1999

One-Dimensional Electronic Structure and Suppression of d-Wave Node State in (La(1.28)Nd(0.6)Sr(0.12))CuO(4).

Angle-resolved photoemission spectroscopy was carried out on (La(1.28)Nd(0.6) Sr(0.12))CuO(4), a model system of the charge- and spin-ordered state, or stripe phase. The electronic structure contains characteristic features consistent with other cuprates, such as the flat band at low energy near the Brillouin zone face. However, the low-energy excitation near the expected d-wave node region is strongly suppressed. The frequency-integrated spectral weight is confined inside one-dimensional segments in the momentum space (defined by horizontal momenta &cjs3539;k(x)&cjs3539; = pi/4 and vertical momenta &cjs3539;k(y)&cjs3539; = pi/4), deviating strongly from the more rounded Fermi surface expected from band calculations. This departure from the two-dimensional Fermi surface persists to a very high energy scale. These results provide important information for establishing a theory to understand the charge and spin ordering in cuprates and their relation with high-temperature superconductivity.

Journal Article↗
PubMed1999

Estimation of breast volume and its variation during the menstrual cycle using MRI and stereology.

Unbiased estimates of breast volume may be obtained in vivo from systematic series of MR images acquired in accordance with the Cavalieri method of modern design-based stereology. The method does not require any assumptions to be made regarding breast shape. If point counting techniques are used to obtain the required breast section areas estimates, 10-15 min analysis (i.e. counting about 250 points on 12 to 16 images) ensures that the contribution of sectioning and point counting to the coefficient of error (CE) on the volume estimate is less than 3%. The methods were applied to measure breast volume in 15 healthy females aged between 22 and 44 years (mean 31.7 years; SD 8.2 years). One subject was studied on every fourth day during two consecutive cycles. The other 14 subjects were studied on three occasions corresponding to menses, ovulation and pre-menses during a single menstrual cycle. Repeat imaging after repositioning on three occasions within a period of 30 min and also at three different times of day for a single subject, both yielded a coefficient of variation (CV) of less than 3% in the estimation of breast volume. ANOVA indicates that there is no significant difference between the mean volume of the left and the right breast (p = 0.294). The mean volume of the left breast is 561 ml (95% confidence interval (CI): 553 ml, 569 ml) and the mean volume of the right breast is 567 ml (95% CI: 559 ml, 576 ml). There are highly significant differences between the three named stages of the menstrual cycle (p < 0.0005), whereby the mean volume at ovulation is 5.5% less than the mean volume at menses (95% CI: 3.0%, 7.9%) and the mean volume pre-menses is 8.1% greater than the mean volume at menses (95% CI: 5.3%, 10.9%). Overall, the volume of each breast varies by an average of 76 ml (95% CI: 61 ml, 92 ml) during the menstrual cycle, which corresponds to 13.6% of the volume at menses (95% CI: 13.3%, 13.8%). No significant interaction was found between the relative volumes of the left and right breast and the stage of the menstrual cycle (p = 0.277), nor between subjects and stages of cycle (p = 0.296). However, a significant interaction was observed between the volume of the left and right breasts in different subjects (p < 0.005). The average difference in the volume of the left and right breasts of all 15 subjects is 39.7 ml (95% CI: 21.3 ml, 58.1 ml), which is 7% of average breast volume and approximately 50% of the average variation in the volume of the breast during the menstrual cycle.

Adult↗