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Biomedical subjects

Z Khan

Publications and source records attributed to Z Khan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Placement of esophageal self-expanding metallic stents without fluoroscopy.

BACKGROUND: Fluoroscopy is routinely used to guide the placement of self-expanding metallic stents for the palliative treatment of patients with esophageal malignancy. This is a description of a novel method of stent placement without fluoroscopy. METHODS: This technique relies on a clear endoscopic view of the proximal radiopaque marker on the stent. This was achieved by the application of an external white marker at this level. A gastroscope was passed, allowing guidewire deployment and measurement of stricture length. The endoscope was reinserted and placed alongside the guidewire giving direct visualization of the proximal margin of the stricture. The stent delivery device was positioned, keeping the white mark visible proximal to the stricture, and the stent was deployed. RESULTS: Thirty consecutive patients with inoperable esophageal malignancy underwent endoscopic placement of self-expanding metal stents. Deployment in satisfactory position without fluoroscopy was successful in 23 of 30 (77%); there were no complications. CONCLUSIONS: The majority of esophageal stents can be accurately positioned without fluoroscopy.

Adenocarcinoma↗
PubMed2001

Effect of adhesive retention of maxillofacial prostheses. Part 2: Time and reapplication effects.

STATEMENT OF PROBLEM: The success of most non-implant-retained extraoral prostheses depends on retention derived from skin adhesives. Part 1 of this study found that Skin-Prep Protective Dressing improved the retentive properties of adhesives and that Secure(2) Medical Adhesive was stronger than Epithane-3. Part 2 investigates the application of a second layer of adhesive to the prosthesis, which was earlier noted to improve retention at later time periods. PURPOSE: This study measured the force needed to remove silicone elastomer strips with Secure(2) Medical Adhesive from the skin of human subjects. Testing was performed before and after the removal of the strips and reapplication of the adhesive. MATERIAL AND METHODS: Secure(2) Medical Adhesive was painted on silicone rubber strips and placed in a nonsequential random order of the 3 variables to 3 sites on the ventral forearms of 21 human subjects and tested over an 8-hour period. The bond strength was measured at 0, 4, and 8 hours. After a reapplication of adhesive over the existing adhesive, additional bond strength measurements were made at 4 and 8 hours. Testing was at 10 cm/min in an Instron. All subjects had Skin-Prep coating applied before adhesive application. RESULTS: Bond strengths for both single applications and reapplications of the adhesive were greater at 0 hours and became significantly weaker after the 4- and 8-hour periods. The second application of the adhesive produced the strongest bonds when measured at 4 hours (110 N/m). Bonding was significantly higher at 8 hours if a second application of adhesive was applied at 0 or 4 hours. CONCLUSION: The results of this study indicate that the bond strength of silicone elastomer to skin decreased over an 8-hour interval. After removal of the silicone rubber strip and reapplication of Secure(2) Medical Adhesive over the existing adhesive, bond strengths increased.

Adhesiveness↗
PubMed2001

A unique, complex variant philadelphia chromosome translocation in a patient with typical chronic myelogenous leukemia.

The Philadelphia (Ph) chromosome [der(22) t(9;22)(q34;q11)] is the characteristic chromosomal abnormality found in chronic myelogenous leukemia (CML). This chromosome has been reported in patients with other chromosomal abnormalities. In this study, we describe a patient with hematologically typical chronic-phase CML with an unusual and complex translocation involving chromosomes 9, 11, and 22. These complex translocations were identified by G-banded conventional cytogenetics and confirmed by fluorescence in situ hybridization (FISH) using whole chromosome painting probes (wcp). To the best of our knowledge, these are unique translocations involving the short and the long arms of chromosome 9 in 4 different translocations with the short arm of chromosome 11 and the long arm of chromosome 22.

Adult↗
PubMed2001

Detection of trisomy 8 in philadelphia chromosome-positive CML patients using conventional cytogenetic and interphase fluorescence in situ hybridization techniques and its relation to c-myc involvement.

Trisomy 8 (+8) is a common clonal evolution marker for progression in chronic myelogenous leukemia. The relationship of +8 to various stages of t(9;22) leukemias is not firmly established. To explore this association we examined bone marrow (BM) cells from 10 Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) patients in different stages of the disease, using conventional cytogenetic technique(CCT) and interphase fluorescence in situ hybridization (FISH). FISH detection of chromosome 8 was accomplished using the D8Z2 (Oncor) probe specific for the centrometric region of chromosome 8. Five hundred interphase nuclei were counted for each patient. Three of the 10 patients were selected for detection of c-myc gene locus located in the 8q24.2-24.3 region using the L

Adult↗
PubMed2001

Acute mountain sickness score and hypoxemia.

BACKGROUND: Hypoxemia is the immediate consequence of hyobaric hypoxia, which is the crucial starting mechanism of acute mountain sickness (AMS). The AMS is generally a benign and self-limiting condition which can be prevented by gradual ascent. However, ascent rates recommended for prophylaxis of AMS are far slower than those attempted during military operations and by climbers. OBJECTIVE: The current study was carried out to quantify the relationship between AMS and hypoxemia alongwith evaluating the benefits of acetazolamide-dexamethasone chemoprophylaxis during acute ascent. SUBJECTS AND METHODS: Twenty-four low lander male adults (age mean +/- SE 27.8 +/- 1.24 years) were selected. They were grouped in a double-blind fashion into four groups and each group (n = 6) received placebo (multivitamin) or acetazolamide (250 mg) or dexamethasone (4 mg) or a combined regimen of the two drugs twice daily for 5 days, commencing 24 hours before ascent. The volunteers reached the altitude of 4578 meters within a span of one day. Their AMS symptoms were recorded on modified environmental symptoms questionnaire (ESQ), after 24 and 72 hours of ascent. Arterial PO2, SO2 and PCO2 were measured by GEMSTAT blood-gas analyzer (Mallincrodt-USA). RESULTS: The ESQ, AMS-C (cerebral) and AMS-R (respiratory) scores of combined therapy group were significantly lower as compared to the other groups on the symptom rating scale. The significant finding amongst the volunteers taking acetazolamide was mild to moderate diuresis whereas severity of headache was markedly less in dexamethasone group. The commonest feature of combined therapy was that none of the volunteers complained of headache, dysponea, irritability and more than mild disturbance of sleep. The ESQ scores of volunteers were inversely correlated to PaO2 and SaO2 after 24 hours of ascent to 4578 meters. CONCLUSION: The study concludes that severity of AMS is closely related to hypoxemia and combination therapy of acetazolamide-dexamethasone may be effective in preventing AMS.

Acetazolamide↗
PubMed2001

The role of the dentist in detection of carotid atherosclerosis.

Cerebrovascular accidents (CVA), or stroke, afflict 731,000 Americans each year, with 165,000 of these individuals dying. Stroke is a major cause of death and disability throughout the world, including southern Africa. Atherosclerosis-related formation of thrombi and emboli at the bifurcation of the common carotid artery and proximal internal carotid artery represents a common cause of stroke. The detection of carotid atherosclerosis by dentists using panoramic radiographs recently has been presented to the public through television news stories and the press, but many dentists still do not know how to interpret panoramic radiographs for detection of this condition. This communication illustrates examples in which carotid atherosclerosis was detected using panoramic radiography. Differential diagnoses are presented. Since not every carotid plaque calcifies, panoramic radiography should never be used alone to exclude the possibility of carotid atherosclerosis. It should also be remembered that the mere presence of calcified carotid plaque is not necessarily a reflection on the degree of carotid stenosis. Definitive diagnosis and treatment requires referral of patients deemed to be at risk to an appropriate physician. A variety of advanced diagnostic methods, including gadolinium-enhanced MRI, Duplex Doppler sonography and angiography are used to confirm carotid stenosis.

Angiography↗
PubMed2000

Antimicrobial susceptibility profile of soil isolates of Nocardia asteroides from Kuwait.

OBJECTIVES: To find the antimicrobial susceptibility profile of 42 soil isolates of Nocardia asteroides against 14 antimicrobial agents representing beta-lactams, aminoglycosides, ciprofloxacin, minocycline, erythromycin and third generation cephalosporins. METHODS: The antimicrobial susceptibility was determined by the disk diffusion method using Mueller-Hinton agar medium. A homogeneous suspension giving an inoculum of 106-108 CFU/mL was used to streak the plates. The zone of inhibition was read after 36-48 h of incubation at 37 degrees C. RESULTS: All the soil isolates of N. asteroides were susceptible to amikacin, imipenem and tobramycin. Susceptibility to cephalosporins was quite variable; 86% of the isolates were susceptible to cefotaxime, 57% to ceftriaxone and 40% to cefamandole. Fifty-seven per cent of the isolates showed intermediate susceptibility to cefamandole, 33% to ceftriaxone and 5% to cefotaxime. Ninety-three per cent of the isolates were resistant to sulfamethoxazole alone or in combination with trimethoprim. CONCLUSIONS: The study reports a wide variation in the antimicrobial susceptibility profile of soil isolates of N. asteroides originating from a single geographical area. Of interest is the finding that over 90% of N. asteroides isolates were resistant to sulfamethoxazole without any previous exposure to this drug. This may have serious therapeutic implications as sulphonamides or the combination of trimethoprim-sulfamethoxazole is the therapy of choice for nocardiosis. Demonstration of resistance to beta-lactam antibiotics may be attributed to the presence of beta-lactamases which was detectable in > 90% of the soil strains of N. asteroides. The study underscores the importance of antimicrobial susceptibility testing for clinical isolates of Nocardia since individual strains show considerable differences in their susceptibility patterns necessitating therapeutic adjustments.

Anti-Bacterial Agents↗
PubMed2000

Effect of adhesive retention on maxillofacial prostheses. Part I: skin dressings and solvent removers.

STATEMENT OF PROBLEM: The success of most maxillofacial prostheses depends on retention by medical adhesives. Products such as Smith-Nephew's Skin-Prep (SP) are available that can be used on the skin that could improve prosthesis adhesion protective dressing. The removal of adhesive from the skin is also problematic, so solvents, such as Uni-Solve adhesive remover (US), are often used. PURPOSE: This study measured the removal force of silicone elastomer strips with 2 adhesives from the skin of human subjects during the day, as affected by the use of SP and US, and determined the site of adhesive failure. MATERIAL AND METHODS: Silicone rubber strips were applied in a predetermined random order to the ventral arm surfaces of 20 human subjects. US was applied to half the sites 1 day before testing. SP was also applied to half the sites just before Epithane-3 (E3) or Secure(2) Medical Adhesive (SMA) were used to adhere the strips. They were peeled from the skin 6 hours later in an Instron at a rate of 10 cm/min. RESULTS: A 3-way within-group MANOVA revealed significant differences without interactions between adhesives (SMA=96.3 N.m, E3=24.1 N.m; P<.0005) and between use or nonuse of SP (SP=65.8 N.m, no SP=54.6 N.m; P<.0005). The use of US was not significant (no US=61.8 N.m, with US=58.6 N.m; P=.197). SMA adhered to the prostheses, whereas E3 adhered to the skin, leaving a residue (Fisher exact test; P<.0003). CONCLUSION: The combination of SMA and SP showed the highest adhesive bond strength. Overall, SMA was 3 to 5 times more retentive than E3. SP improved adhesion of both SMA (15%) and E3 (27%). SMA was still far more retentive. US had no effect on retention. SMA remained on the prostheses, whereas E3 left a difficult-to-remove residue on the skin.

Adhesiveness↗
PubMed2000

Measles antibody titre in children up to 5 years of age in rural areas of Aligarh District, India.

OBJECTIVE: To determine the pattern of decline of maternal antibodies in 0-9 month old infants and to study the prevalence of measle antibodies and their levels in 9 month to 5 year old children, regardless of their immunization status. METHODS: A cross-sectional study covering 456 children in the 0-5 year age group residing in 9 registered villages in a rural area of Aligarh District was conducted. The study included the interview of parents, clinical examination of children, and Hemagglutination Inhibition Test for Measles Antibody Titre. RESULTS: There was rapid decline in seropositivity from 100% in the 0-3 month age group to 18% in the 6-9 month age group. There was a positive correlation (r = 0.77) between decline of seropositivity and age. Measle immunization coverage rate was 64.5%. In 202 children where immunization was confirmed by availability of card, sero-conversion was 96.5%. Of the 118 unvaccinated children, 9% were sero-positive. Of the 71 children who had a history of measles infection, 75% were seropositive indicating correct identification of measle infection by the parents.

Age Distribution↗
PubMed1999

The Micelle-Induced Interaction between Ninhydrin and Tryptophan.

The effects of micelles of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB) on the observed pseudo-first-order rate constants for the interaction of ninhydrin with tryptophan were studied. The influence of different parameters was considered, i.e., reactant concentration, surfactant concentration, temperature, and effect of added salts. The data are explained in terms of the pseudo-phase model of the micelles. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Effect of Cationic Micelles on the Kinetics of Interaction of Ninhydrin with l-Leucine and l-Phenylalanine.

The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) and N-cetylpyridinium bromide (CPB) on the interaction of l-leucine and l-phenylalanine with ninhydrin have been studied at 70 degrees C. Both surfactants strongly catalyze the reactions. The reaction rates are higher in CTAB micelles than in CPB micelles. Quantitative kinetic analysis has been performed on the basis of a pseudo-phase model. The influence of different salts on the reaction rates has also been seen and it is found that tightly bound/incorporated counterions are the most effective. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Pilocarpine tablets for the treatment of dry mouth and dry eye symptoms in patients with Sjögren syndrome: a randomized, placebo-controlled, fixed-dose, multicenter trial. P92-01 Study Group.

BACKGROUND: Patients with Sjögren syndrome (SS) experience slowly progressive infiltration of lacrimal and salivary glands by mononuclear cells. This leads to diminished secretions, with resultant symptoms of xerostomia and xerophthalmia. Although pilocarpine hydrochloride tablets are currently indicated for the treatment of radiation-induced xerostomia, their effects on dry mouth or dry eyes in patients with SS are unclear. OBJECTIVE: To assess the safety and efficacy of pilocarpine (Salagen) tablets as symptomatic treatment for dry mouth and dry eyes caused by SS in a multicenter, doubleblind, placebo-controlled trial. METHODS: After providing written informed consent, 373 patients with primary or secondary SS and clinically significant dry mouth and dry eyes were randomized to receive 2.5-mg pilocarpine, 5-mg pilocarpine, or placebo tablets 4 times daily for 12 weeks. Symptoms were assessed by questionnaires with visual analog scales or categorical checkboxes. Whole-mouth salivary flow rates were measured. RESULTS: A significantly greater proportion of patients in the 5-mg pilocarpine group showed improvement compared with the placebo group (P< or =.01) in global assessments of dry mouth, dry eyes, and other symptoms of dryness (P< or =.05). Salivary flow was significantly increased 2- to 3-fold (P<.001) after administration of the first dose and was maintained throughout the 12-week study. The most common adverse effect was sweating, and no serious drug-related adverse experiences were reported. CONCLUSION: Administration of 5-mg pilocarpine tablets 4 times daily (20 mg/d) was well tolerated and produced significant improvement in symptoms of dry mouth and dry eyes and other xeroses in patients with SS.

Adult↗
PubMed1999

Simplified methods for fabricating tissue-supported implant-retained overdentures with retention from a resilient liner.

Resilient denture liner materials can be useful for tissue-supported implant-retained overdentures. They allow physiologic movement of the denture toward the tissues. This article presents a technique that offers several advantages over other methods of fabricating the overdenture with a resilient liner, and of transferring the superstructure: the acrylic resin base and the heat-cured resilient liner material are cured simultaneously; superstructure blockout is performed in the laboratory instead of in the mouth, where blockout is difficult; and direct transfer of the superstructure bar is more accurate and eliminates possible fracture of the duplicated superstructure if formed in die stone.

Acrylic Resins↗
PubMed1999

Overdenture retention of four resilient liners over an implant bar.

STATEMENT OF PROBLEM: Resilient denture liners offer an alternative method of designing implant-retained overdentures. Space is provided in the overdenture to envelop the implant bar with a resilient liner to be applied chairside or processed in the laboratory. The degree of retention may vary and these materials change over time. PURPOSE: This study evaluated the retention on an implant/bar prosthesis with overdentures lined with 4 resilient denture lining materials, after cyclic insertion and removal over a simulated 1.5-year period. MATERIAL AND METHODS: Four implants were placed in a mandibular edentulous cast and a gold bar superstructure was made. Overdentures were processed in Lucitone-199 and Tokuyama, Luci-Sof, Molloplast-B, and PermaSoft (with and without sealer) lining materials, cured according to manufacturers' instructions. Each of 5 overdentures contained each liner and were cycled 2740 times (simulating 1.5 years of service at 5 insertions daily) in 37 degrees C water in an Instron at 20 cm/min. Insertion and retention force were measured. RESULTS: The 3 silicone rubber liners were 3 to 5 times more retentive than the plasticized acrylic liner initially. After cycling, Tokuyama soft liner (autopolymerized silicone) gained 14% retention, Luci-Sof (heat-cured silicone) gained 8%, Molloplast-B (heat-cured silicone) lost 12%, whereas PermaSoft (autopolymerized plasticized acrylic) with sealer lost 43%, and without sealer lost 60%. PermaSoft lining material also chafed and crumbled after cycling and was significantly less retentive in most statistical comparisons. CONCLUSIONS: All the silicone-based resilient liners retained the overdentures well. The plasticized acrylic was less retentive initially, and lost significant retention after 2740 cycles, compared with silicone-based resilient liners.

Acrylic Resins↗