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Biomedical subjects

A Khan

Publications and source records attributed to A Khan.

At least 127 records · Page 7Linked to original sources
PubMed2004

Surveillance of endophthalmitis following cataract surgery in the UK.

AIMS: To estimate the incidence of acute-onset presumed infectious endophthalmitis (PIE) following cataract surgery in the UK and provide epidemiological data on the presentation, management, microbiology, and outcome of cases of endophthalmitis. METHODS: Cases were identified prospectively by active surveillance through the British Ophthalmological Surveillance Unit reporting card system, for the 12-month period October 1999 to September 2000 inclusive. Questionnaire data were obtained from ophthalmologists throughout the UK at baseline and 6 months after diagnosis. Under-reporting was estimated by independently contacting units with infection databases. RESULTS: Data were available on 213 patients at baseline and 201 patients at follow-up. The minimum estimated incidence of PIE was 0.086 per 100 cataract extractions and the corrected incidence was 0.14 per 100 cataract extractions. For the management of PIE, 96% of patients received intravitreal, 30% subconjunctival, 65% oral, and 17% intravenous antibiotics. In all, 17% of patients received intravitreal steroid. From the intraocular samples taken for microbiological analysis, 56% were culture positive. At follow-up, 48% of patients achieved visual acuity of 6/12 or better and 66% achieved better than 6/60. 13% of patients were unable to perceive light or had evisceration of the globe. CONCLUSIONS: The incidence of PIE after cataract surgery in the UK is comparable to that of other studies. Approximately 50% of patients achieved a visual acuity close to the driving standard.

Acute Disease↗
PubMed2004

Robot-assisted Bricker ileoureteral anastomosis during intracorporeal laparoscopic ileal conduit urinary diversion for prostatocutaneous fistula: case report.

BACKGROUND AND PURPOSE: The da Vinci robot is useful during minimally invasive surgery in performing intracorporeal suturing. We report one case of its application during laparoscopic ileal conduit urinary diversion for prostatocutaneous fistula. METHODS: A 58-year-old paraplegic man with a neurogenic bladder and bowel and a long history of urinary incontinence developed a prostatocutaneous fistula after numerous procedures to correct the incontinence. He underwent laparoscopic ileal conduit urinary diversion to improve his quality of life. The da Vinci robot was used to perform the ileoureteral anastomosis. RESULTS: The operative time was 10 hours. The estimated blood loss was <100 mL. There were no intraoperative complications. The patient was started on a clear liquid diet on postoperative day 3. There was no narcotic use because of the patient's neurologic status. The patient was discharged home on day 6. CONCLUSION: Laparoscopic urinary diversion remains a technically challenging procedure. The da Vinci robot is useful during laparoscopic ileal conduit construction.

Anastomosis, Surgical↗
PubMed2004

Differential impact of some Aspergillus species on Meloidogyne javanica biocontrol by Pseudomonas fluorescens strain CHA0.

AIMS: The aim was to determine the influence of some Aspergillus species on the production of nematicidal agent(s) in vitro and biocontrol of Meloidogyne javanica in tomato by Pseudomonas fluorescens strains CHA0 and CHA0/pME3424. METHODS AND RESULTS: Six species of Aspergillus, isolated from the rhizosphere of certain crops, produced a variety of secondary metabolites in vitro. Culture filtrate (CF) obtained from Ps. fluorescens strain CHA0 and its2,4-diacetylphloroglucinol overproducing mutant CHA0/pME3424 grown in King's B liquid medium caused significant mortality of M. javanica juveniles in vitro. Bacterial growth medium amended with CF of A. niger enhanced nematicidal and beta-galactosidase activities of fluorescent pseudomonads while A. quadrilineatus repressed such activities. Methanol or ethyl acetate extracts of the CF of A. niger markedly optimized bacterial efficacy to cause nematode deaths while hexane extract of the fungus had no influence on the nematicidal activity of the bacterial strains. A. niger applied alone or in conjunction with the bacterial inoculants inhibited root-knot nematode galling in tomato. On the other hand, A. quadrilineatus used alone or together with CHA0 did not inhibit nematode galling but when used in combination with strain CHA0/pME3424 did reduce galling intensity. CONCLUSIONS: Aspergillus niger enhances the production of nematicidal compounds by Ps. fluorescensin vitro and improves biocontrol potential of the bacterial inoculants in tomato while A. quadrilineatus reduces bacterial performance to suppress root-knot nematodes. SIGNIFICANCE AND IMPACT OF THE STUDY: Rhizosphere harbours a variety of micro-organisms including bacteria, fungi and viruses. Aspergillus species are ubiquitous in most agricultural soils and generally produce a variety of secondary metabolites. Such metabolites synthesized by Aspergillus species may influence the production of nematicidal agents and subsequent biocontrol performance of the bacterial inoculants against plant-parasitic nematodes. This fact needs to be taken into consideration when using biocontrol strains in an agriculture system.

Animals↗
PubMed2004

beta-Catenin expression in thyroid follicular lesions: potential role in nuclear envelope changes in papillary carcinomas.

The morphologic distinction of benign and malignant thyroid follicular lesions can sometimes be challenging, therefore an immunohistochemical marker to aid in this distinction would be useful. beta-Catenin is one such potential marker. It is part of a membrane-bound cell growth-signaling complex that plays a role in cell adhesion, as well as in promotion of growth through activation of the Wnt signaling pathway. Oncogenic signaling occurs when beta-catenin is released, accumulates in the cytoplasm, translocates into the nucleus, and promotes transcription of genes including bcl-1 (cyclin D1) and c-myc that induce cell proliferation. Paraffin blocks from 133 thyroidectomy specimens were stained with monoclonal antibodies reactive with beta-catenin and cyclin D1. These included 53 cases of papillary thyroid carcinoma (PTC), 46 cases of follicular variant of papillary carcinoma (FVPC), 10 cases of follicular carcinoma (FC), and 24 cases of follicular adenoma (FA). Tissue from six normal thyroid specimens served as a control. The malignant lesions (PTC, FC, and FVPC) expressed strong cytoplasmic/nuclear staining and minimal residual membranous staining in 87%, 80%, and 71% of cases, respectively. In contrast, all normal thyroid tissue and 79% of FAs showed strong membranous reactivity with very minimal cytoplasmic staining. Interestingly, in 83% of PTC cases and 20% FVPCs, the intranuclear inclusions were distinctly beta-catenin positive. Cyclin D1 over expression correlated with cytoplasmic relocalization of beta-catenin in almost all cases, and no evidence of cyclin D1 gene amplification was observed. beta-Catenin can be of a diagnostic utility for thyroid lesions, because it highlights intranuclear inclusions in PTC, and shifts from a membranous localization to a cytoplasmic localization in malignant lesions. We speculate that the localization of beta-catenin in intranuclear inclusions may reflect a cytoskeletal remodeling activity of beta-catenin that is functionally significant for the PTC pathway.

Adenocarcinoma, Follicular↗
PubMed2003

Do distal adenomas mandate total colonoscopy?

BACKGROUND: Distal adenomas have been considered markers of proximal neoplasms. It also has been suggested that patients with small, distal adenomas do not require proximal examination of the colon. This study was conducted to determine the validity of the latter recommendation. METHODS: From a total of 5,132 colonoscopies performed between 1976 and 1999, all patients from whom adenomas were removed were included. Those with previous colon resections or incomplete cecal intubation were excluded. Proximal adenomas were defined as those proximal to the sigmoid colon. Adenomas were considered advanced if they were 1 cm or larger, contained any villous component, or demonstrated severe dysplasia. RESULTS: The study included 226 patients. Overall, 98 patients had distal adenomas, and there was a synchronous proximal adenomas rate of 23.4%. Patients with single, small, rectosigmoid, tubular adenomas had proximal adenomas at a rate of 28.8%, and 9.6% were advanced adenomas. Patients with advanced distal adenomas had synchronous proximal adenomas at a rate of 18.9%, and 10.8% of these were advanced adenomas. According to multiple logistic regression, the strongest predictor of proximal neoplasia was the absence of distal polyps. CONCLUSION: These data confirm the necessity for total colonoscopy in all patients with distal adenomas regardless of size. In addition, the high proportion of proximal neoplasia without distal markers suggests that full colonoscopy may be warranted as a screening tool in all patients.

Adenoma↗
PubMed2003

The antennal system and cockroach evasive behavior. I. Roles for visual and mechanosensory cues in the response.

Cockroaches escape from predators by turning and then running. This behavior can be elicited when stimuli deflect one of the rostrally located and highly mobile antennae. We analyzed the behavior of cockroaches, under free-ranging conditions with videography or tethered in a motion tracking system, to determine (1) how antennal positional dynamics influence escape turning, and (2) if visual cues have any influence on antennal mediated escape. The spatial orientation of the long antennal flagellum at the time of tactile stimulation affected the direction of resultant escape turns. However, the sign of flagellar displacement caused by touch stimuli, whether it was deflected medially or laterally for example, did not affect the directionality of turns. Responsiveness to touch stimuli, and escape turn performance, were not altered by blocking vision. However, because cockroaches first orient an antenna toward stimuli entering the peripheral visual field, turn direction can be indirectly influenced by visual input. Finally, when vision was blocked, the run phase of escape responses displayed reduced average velocities and distances traveled. Our results suggest that tactile and visual influences are integrated with previously known wind-sensory mechanisms to achieve multisensory control of the full escape response.

Animals↗
PubMed2003

Matrix metalloproteinases are not involved in early brain edema formation after cardiac arrest in rats.

INTRODUCTION: Resuscitation from cardiac arrest (CA) often results in a poor neurological outcome possibly due to an incomplete understanding of the pathophysiology of brain injury following CA-induced global cerebral ischemia. Brain edema is an important manifestation after CA and is associated with significant morbidity and mortality. The matrix metalloproteinases (MMPs) contribute to brain edema formation following focal cerebral ischemia. The objective of this study was to investigate the role of an MMP inhibitor, GM6001, in CA-elicited brain edema. METHODS: Eighteen rats were subjected to normothermic (37.5 +/- 0.5 degrees C) CA induced by eight minutes of asphyxiation and assigned to a CA-control group (CA), an alcohol-placebo group (CA + ETOH), or a GM6001-treated group (CA + GM6001). GM6001 in 100% alcohol or a vehicle was given i.v. before CA to achieve a whole blood concentration of 10 microM. Animals were resuscitated with CPR, ventilation and epinephrine. Brain edema was determined by brain wet-to-dry weight ratio at one hour after resuscitation. FINDINGS: Brain wet-to-dry weight ratio was 4.86 +/- 0.09 in CA, 4.76 +/- 0.12 in CA + ETOH (p = 0.30 vs. CA), and 4.72 +/- 0.03 in CA + GM6001 (p = 0.17 vs. CA and 0.42 vs. CA + ETOH). INTERPRETATION: MMPs are not involved in brain edema formation one hour following CA.

Animals↗
PubMed2003

Molecular evolution and phylogeny of elapid snake venom three-finger toxins.

Animal venom components are of considerable interest to researchers across a wide variety of disciplines, including molecular biology, biochemistry, medicine, and evolutionary genetics. The three-finger family of snake venom peptides is a particularly interesting and biochemically complex group of venom peptides, because they are encoded by a large multigene family and display a diverse array of functional activities. In addition, understanding how this complex and highly varied multigene family evolved is an interesting question to researchers investigating the biochemical diversity of these peptides and their impact on human health. Therefore, the purpose of our study was to investigate the long-term evolutionary patterns exhibited by these snake venom toxins to understand the mechanisms by which they diversified into a large, biochemically diverse, multigene family. Our results show a much greater diversity of family members than was previously known, including a number of subfamilies that did not fall within any previously identified groups with characterized activities. In addition, we found that the long-term evolutionary processes that gave rise to the diversity of three-finger toxins are consistent with the birth-and-death model of multigene family evolution. It is anticipated that this "three-finger toxin toolkit" will prove to be useful in providing a clearer picture of the diversity of investigational ligands or potential therapeutics available within this important family.

Amino Acid Sequence↗
PubMed2003

Evaluation of patient concerns before total knee and hip arthroplasty.

The preoperative concerns of patients undergoing total knee or hip arthroplasty were evaluated in a cross-sectional study of 370 patients. Patients completed a questionnaire on 29 concerns, each rated on a scale of 1 (not concerned) to 4 (very concerned). Short Form 12 and Oxford hip or knee scores were also calculated. The results showed that the greatest concern for patients was cancellation of the surgery. This was followed by failure of the surgery to reduce pain, loss of a limb, and joint infection. Concerns regarding scar problems, nursing care, and preoperative tests were the lowest. Women showed statistically significant greater concerns in 9 areas. Younger patients (age, <65) showed increased concerns in 8 areas. Patients who had previously undergone joint arthroplasty were less concerned than those who had not undergone previous lower limb joint arthroplasty for 6 responses. They showed increased concern in 2 areas, nursing care and hospital food. Those undergoing total hip arthroplasty were more concerned about dislocation, dressing, and returning to work (all, P<.05). This study provides useful information for the preoperative counseling of patients and the production of preoperative literature.

Adult↗
PubMed2003

Environmental isolates of Citrobacter braakii that agglutinate with Escherichia coli O157 antiserum but do not possess the genes responsible for the biosynthesis of O157 somatic antigen.

While searching for Escherichia coli O157 in the aquatic environment of Calcutta using an immunodetection procedure, we fortuitously detected five strains of Citrobacter braakii, which cross-reacted with the commercially available O157 polyvalent antiserum. The five C. braakii isolates gave positive results when a sensitive dot-ELISA was performed with E. coli O157 monoclonal antibody. Further, the O157 monoclonal antibody recognized the bands of proteinase K treated whole cells of lipopolysaccharide of all the C. braakii isolates. Apart from weak reactions with two or three of the DNA probes, all the C. braakii strains did not hybridize with the other probes spanning the minimum region required for O157 O-antigen biosynthesis. These strains did not possess any of the virulence genes that are commonly found in the Shiga toxin-producing E. coli (STEC) specially the serotype O157: H7. Therefore, it appears that the serological cross-reaction between C. braakii and E. coli O157 antiserum is based on structural mimicry between the O-polysaccharide of C. braakii and E. coli O157.

Agglutination↗
PubMed2003

Pathological effects of formalin (37% formaldehyde) mixed in feed or administered into the crops of White Leghorn cockerels.

This study compared the adverse effects of formalin administered by two different methods. Formalin mixed with the feed (2.5, 5.0 and 10 ml/kg) was given to 10-week-old White Leghorn cockerels for a period of 8 weeks. Simultaneously in other groups, a 3% solution of formalin was administered into the crops (5, 10, 15 and 20 ml/bird/day). Total amount of formalin utilized during the experiment in the feed of individual bird of groups given 2.5, 5 and 10 ml/kg was 6.25, 3.9 and 1.6% higher than those administered 5, 10 and 20 ml of 3% formalin into crop, respectively. Body mass and feed intake in all feed-mixed groups and those given 5 and 10 ml formalin (3%) into the crop were not significantly different from control. Administration of 15 and 20 ml formalin (3%) into crop resulted in depression, delayed onset of crowing, significantly decreased feed intake, lower body mass, decreased mass and volume of testes, ulceration in crops, sloughing of mucosa and petechial haemorrhages in proventriculus. All the groups given formalin had significantly smaller diameters of seminiferous tubules. Kidneys of the birds administered formalin into crop exhibited pyknotic nuclei of epithelial cells in proximal tubules. Non-significant differences in different parameters and lesser degree of pathological changes in birds given formalin-mixed feed than their corresponding crop-administered groups suggested that formalin present in the feed had partially evaporated. Therefore, birds ingested less amount of formalin than that originally mixed in the feed.

Administration, Oral↗
PubMed2003

The infection process of Colletotrichum graminicola and relative aggressiveness on four turfgrass species.

Detached 3-week-old leaves of Agrostis palustris, Lolium perenne, Poa annua, and Poa pratensis were inoculated with conidial suspensions of two isolates of Colletotrichum graminicola obtained from A. palustris. Inoculated leaves were incubated at 23 degrees C under high relative humidity (>95%). The infection process was investigated by light microscopy from 2 to 168 h after inoculation (AI). Spore germination was observed within 2 h AI, appressoria within 6 h AI, and penetration pores within 8 h AI on all four hosts. Infection hyphae were observed inside epidermal cells within 24 h AI on all four hosts, but significantly greater infection was observed in A. palustris and P. annua than in L. perenne or P. pratensis at both 96 and 120 h AI. Acervuli appeared on leaves of A. palustris at 72 h AI and on L. perenne at 96 h AI but were not found on either P. annua or P. pratensis during the first 168 h AI. The infection process was similar to that reported for C. graminicola from other hosts; however, disease development of the two isolates of C. graminicola from A. palustris was faster or fungal growth more extensive on detached leaf tissue of A. palustris than on other turfgrass species tested.

Agrostis↗
PubMed2003

Expect the best, prepare for the worst: surgeon and patient expectation of the outcome of primary total hip and knee replacement.

A cross-sectional study of 100 surgeons and 370 patients awaiting primary total hip or knee replacement was carried out. Oxford hip or knee score questionnaires were sent to the surgeons and patients. They were asked to predict the level of symptoms expected 6 months following surgery. The Oxford scores derive a value of 12-60, with a greater score indicating worsening symptoms. The mean pre-operative score was 45.12 for the hip patients and 42.96 for the knee patients, and the patients expected this to drop to 23.70 and 25.66, respectively, 6 months' postoperatively. This was a significant difference for both groups. The surgeons expected the patients to have a mean postoperative score of 20.91 for the hip group and 22.19 for the knee group. The surgeons' scores were significantly lower than those from the patients. There was a significant difference between the patients' and surgeons' expectations of the results of total knee and hip replacement surgery. The surgeons expected better results than the patients. We believe that this is the first study that directly compares surgeon and patient expectations of lower limb arthroplasty.

Adult↗
PubMed2003

Hantaviruses: a tale of two hemispheres.

Infectious febrile nephropathies, initially described as epidemics during military campaigns in Europe and Asia at the turn of the 20(th) century, were eventually all unified under the rubric of hemorrhagic fever with renal syndrome (HFRS) and ascribed to infection from rodent-borne hantaviruses. At the end of the century, hantavirus pulmonary syndrome (HPS) was described throughout the Americas as a consequence of infection with the New World hantaviruses. The epidemiology and clinical manifestations of these diseases are linked to the ecology of their associated rodent hosts. Murine rodents (Old World mice and rats) are associated with the severe forms of HFRS in Asia and the Balkans due to Hantaan, Dobrava, and Seoul viruses. Hantaan virus causes an estimated 50-100,000 infections a year in China alone. Arvicoline rodents (voles) are associated with a mild form of HFRS in Europe called nephropathia epidemica due to Puumala virus. Sigmodontine rodents (New World rats and mice) are associated with approximately 200 HPS cases per year throughout the Americas caused by over a dozen viruses. The viruses are mainly transmitted as small-particle aerosols of rodent excreta, and the subsequent infections share cardiovascular shock as a prominent feature, although HFRS causes predominantly renal disease, while HPS causes a predominantly non-cardiogenic pulmonary edema - hemorrhage involvement varies in the syndromes on the basis of virus subtypes. Efforts are underway to refine prevention strategies, understand the pathogenesis of the shock, and identify therapeutic modalities.

Animals↗