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Biomedical subjects

N Malik

Publications and source records attributed to N Malik.

At least 19 recordsLinked to original sources
PubMed2007

Vascular delivery of c-myc antisense from cationically modified phosphorylcholine coated stents.

c-Myc is involved in the formation of neointimal hyperplasia. We investigated in vitro, ex vivo and in vivo release of antisense c-myc from cationically modified phosphorylcholine-coated stents, as well as the effects on c-Myc expression and neointima formation in a porcine coronary stent model. In vitro experiments were performed to determine optimal loading of stents with antisense. Stents loaded with labelled antisense were deployed in porcine arteries ex vivo and in vivo. Antisense was detected in the vessel wall directly surrounding the stent of pig carotid and coronary artery up to 48 h after stent deployment. Nuclear uptake was observed in endothelial and vascular smooth muscle cells. Labelled antisense within peripheral tissues in vivo was <1.0% of that within stented arterial segments. Control and antisense loaded stents implanted into 10 pig coronary arteries and analysed at 28 days post-stenting showed that lumen area within the antisense stents was significantly increased (i.e. 30.5% greater, P<0.01), whilst both neointimal area and neointimal thickness were significantly reduced (17.5% and 19.5%, respectively, P<0.01) compared to control stents. Cationically modified phosphorylcholine coated stent-based delivery of c-myc antisense is feasible with minimal systemic delivery and is associated with a reduction of in-stent neointimal hyperplasia in pig coronary arteries.

Animals↗
PubMed2006

Ossiculoplasty: a UK survey.

The aim of this study was to assess and quantify the current surgical practice of ossiculoplasty among British otolaryngology consultants, using a postal questionnaire. Ossiculoplasty is not a very common procedure. It is only performed by otologists with a special interest in ossiculoplasty. Among the 280 respondents (response rate 51.9 per cent), only 179 (63.9 per cent) performed ossiculoplasty. The majority of the consultants (86.5 per cent) used artificial prostheses, and 63.7 per cent used patients' own ossicles (autografts). Most of the consultants (77.6 per cent) performed ossiculoplasty with primary tympanoplasty surgery rather than with primary cholesteatoma surgery (46.3 per cent). The majority of the consultants (50.8 per cent) performed less than 10 ossiculoplasties per year. This is the first survey on ossiculoplasty surgery in the United Kingdom.

Attitude of Health Personnel↗
PubMed2006

Osteogenesis imperfecta.

Osteogenesis imperfecta is an inherited disorder of the connective tissue. The extreme bone fragility seen in patients suffering from osteogenesis imperfecta pose a series of problems with regard to behavior management and rendering of quality dental treatment. Presented here a case of a four year old child suffering from osteogenesis imperfecta.

Alveolar Bone Loss↗
PubMed2004

Awareness and practices of contraception among Pakistani women attending a tertiary care hospital.

Pakistan is one of the most populous nations in the world, with an annual growth rate of 2.8 and high total fertility rate, even among developing nations. The Pakistan Reproductive Health and Family Planning Survey highlighted the wide gap between knowledge (97%) and use of contraceptives (28%) among currently married women. Our actual need is to enhance contraceptive practice in our country. This study was designed to investigate contraceptive knowledge and practice in Pakistani women attending a tertiary care hospital. This questionnaire-based study was conducted at the Gynaecology Unit II of Sir Ganga Ram Hospital, Fatima Jinnah Medical College, Lahore, Pakistan. A total of 204 married women of reproductive age were interviewed by a registrar to record their age, occupation, educational status, number of children, knowledge about contraceptive methods, source of the knowledge, attitudes and practices of contraception. About 57% of women were between 26 and 35 years of age, while 52% of men were between 31 and 40 years. Educational status of the majority of females was below matriculation (33%), while 34% males were above matriculation; 88% of females were housewives and less than 1% of men were out of work. Regarding the social status of couples, 64% were living on income less than 5000 rupees /month (about 60 pound sterling). Of the women, 67% were para 2-5; 68% had some sort of awareness regarding contraception. The main source of information was television (26%) and relatives (24%). The majority knew about the pill (68%) and IUCD (55%). Only 47% were using some sort of contraception. The most common method chosen was the barrier method (15%), followed by IUCD (10%) and the pill (10%). The least common methods were sterilisation (2%) and the rhythm method (2%); 85% of the women and 74% of the men in the study group had a positive attitude toward contraception. In order to improve contraceptive use in Pakistan we need to use multiple media sources to educate couples and their parents regarding contraceptive services, strengthen the perceptions that religion not only allows but also recommends family planning and to create awareness among women to have their rights and opinions about the size of family. The concept of differentiation between sons and daughters should be discouraged. In addition government and non-governmental organisations (NGOs) should organise groups to provide counselling and promotion of contraceptive services at the doorstep. We must act as a team to control our growth rate for economic stabilisation of the country and to raise the living standards of our people.

Adult↗
PubMed2004

Norovirus cross-contamination during food handling and interruption of virus transfer by hand antisepsis: experiments with feline calicivirus as a surrogate.

While there is good epidemiological evidence for foods as vehicles for norovirus transmission, the precise means of spread and its control remain unknown. The feline calicivirus was used as a surrogate for noroviruses to study infectious virus transfer between hands and selected types of foods and environmental surfaces. Assessment of the potential of selected topicals in interrupting such virus transfer was also made. Ten microliters of inoculum of feline calicivirus deposited onto each fingerpad of adult subjects was allowed to air dry and the contaminated area on individual fingerpads was pressed (10 s at a pressure of 0.2 to 0.4 kg/cm2) onto 1-cm-diameter disks of ham, lettuce, or brushed stainless steel. The virus remaining on the donor and that transferred to the recipient surfaces was eluted and plaque assayed. Virus transfer to clean hands from experimentally contaminated disks of ham, lettuce, and stainless steel was also tested. Nearly 46 +/- 20.3, 18 +/- 5.7, and 13 +/- 3.6% of infectious virus was transferred from contaminated fingerpads to ham, lettuce, and metal disks, respectively. In contrast, approximately 6 +/- 1.8, 14 +/- 3.5, and 7 +/- 1.9% virus transfer occurred, respectively, from ham, lettuce, and metal disks to hands. One-way analysis of variance test showed that pretreatment (washing) of the fingerpads either with water or with both topical agent and water significantly (P < 0.05) reduced virus transfer to < or = 0.9%, as compared with < or = 2.3 and < or = 3.4% transfer following treatments with either 75% (vol/vol) ethanol or a commercial hand gel containing 62% ethanol, respectively. Despite wide variations in virus transfer among the targeted items used, intervention agents tested reduced virus transfer significantly (P < 0.05) when compared with that without such treatments (71 +/- 8.9%). These findings should help in a better assessment of the potential for cross-contamination of foods during handling and also assist in developing more effective approaches to foodborne spread of norovirus infections.

Disinfection↗
PubMed2003

A feline kidney cell line-based plaque assay for feline calicivirus, a surrogate for Norwalk virus.

Feline calicivirus (FCV) has been used by researchers as a surrogate for Norwalk virus (NV), since they share a similar genomic organization, physicochemical characteristics, and are grouped in the same family, Caliciviridae. Unlike NV, however, FCV can grow in established cell lines and produce a syncytial form of cytopathic effect. In this report, we describe the development and standardization of a plaque assay for FCV using monolayers of an established line of feline kidney (CrFK) cells in 12-well cell culture plates. The assay method has demonstrated reproducibility, ease of performance and resulted in clear plaque zones, readable in 24 h after virus inoculation. The infectivity titre of the virus by this plaque assay agreed well with tissue culture infectious dose(50) (TCID(50)) determinations. The described plaque assay would be a valuable tool in conducting various quantitative investigations using FCV as a model for NV and Norwalk-like viruses (NLV).

Animals↗
PubMed2003

Cold chain monitoring of OPV at transit levels in India: correlation of VVM and potency status.

We have conducted a study to analyze monitoring of the cold chain of 674 OPV field samples collected at four different levels of vaccine distribution viz., immunization clinics, district stores, hospitals and Primary Health Centers (PHC) from states of Uttar Pradesh, Madhya Pradesh, and Delhi. The study design included: collection and scoring of vaccine vial monitor (VVM) status of the samples and testing for total oral polio virus concentration (TOPV) by standard WHO protocol. Ten samples each were exposed to 25 degrees C and 37 degrees C, and 10 samples as controls were kept at -20 degrees C. VVM were scored daily till they attained grade 4 and each sample was subsequently subjected to potency testing for individual polio serotypes 1, 2 and 3, and TOPV. Of the 674 samples tested it was observed that: samples from immunization clinics and district stores had an acceptable VVM score of grade 1 and 2; however the probable risk that a sub potent vaccine could have been administered was 2.15%. In 2.5% samples received from district stores vaccine had a VVM score of grade 3 (i.e., discard point), although vaccine when tested was found to be potent (i.e., leading to the vaccine wastage). With exposure to higher temperatures, VVM changed score to grade 2 and 3 when the vaccine was kept at 25 degrees C/37 degrees C, and the titres of individual serotypes 1, 2 and 3 and TOPV were beyond the acceptable limits. Important observations at the different levels of vaccine distribution network and correlation of VVM and potency status of OPV are discussed in the paper which will be of help to the EPI program managers at different transit levels.

Cold Temperature↗
PubMed2001

Advances ofcapillary electrophoresis in clinical and forensic analysis (1999-2000).

In this paper, capillary electrophoresis in clinical and forensic analysis is reviewed on the basis of the literature of 1999, 2000 and the first papers in 2001. An overview of progress relevant examples for each major field of application, namely (i) analysis of drug seizures, explosives residues, gunshot residues and inks, (ii) monitoring of drugs, endogenous small molecules and ions in biofluids and tissues, (iii) general screening for serum proteins and analysis of specific proteins (carbohydrate deficient transferrin, alpha1-antitrypsin, lipoproteins and hemoglobins) in biological fluids, and (iv) analysis of nucleic acids and oligonucleotides in biological samples, including oligonucleotide therapeutics, are presented.

Clinical Chemistry Tests↗
PubMed2001

Collagen as a model system to investigate the use of aspirin as an inhibitor of protein glycation and crosslinking.

Aspirin has been shown to be a powerful inhibitor of post-Amadori Maillard reactions, although the exact mechanism of this action remains unclear. We have used corneal and scleral collagen as a model system: (i) to assess how aspirin, either alone or in combination with sugars, affects the surface charge distribution along the collagen fibrils; (ii) to see how sugars and/or aspirin affect the swelling properties of the cornea; and (iii) to see if sugars and/or aspirin change the distribution of water within the corneal stroma as the tissue swells. Charge changes were detected by examining changes in the uptake of phosphotungstate ions as seen in the electron microscope. Swelling was measured by monitoring the uptake of water as a function of swelling time, and water distribution was determined by using synchrotron X-ray diffraction to follow changes in the interfibrillar Bragg spacing as the cornea swells. Aspirin has a marked effect on the positive staining pattern of scleral collagen. This is different to the changes in stain uptake produced by glycation. Incubation with both sugars and aspirin showed that the sugar binding takes precedence over the effects of aspirin which, in turn, suggests that protein acetylation by aspirin is unlikely under these circumstances. However, aspirin completely suppresses corneal swelling. Even when the aspirin is removed, swelling in distilled water is reduced, and this is accompanied by changes in the water distribution. The results suggest that water is more evenly distributed in aspirin-treated corneas that are subsequently swollen than in swollen glycated corneas. Fructation, glucation and ribation on their own have little effect on the uptake of water as the cornea swells. This suggests that any sugar-derived crosslinks formed at this stage do not limit swelling.

Animals↗
PubMed2001

Candidal infections as a cause of recurrent uretero-ileal anastomotic dehiscence.

Fungal infections are common in immunocompromised patients. The presentation is often subtle and therefore treatment is delayed. Uretero-ileal anastomotic dehiscence due to candidal infection has never been reported before. This case represents an uncommon but potentially life-threatening complication in reconstructive surgery; that is, anastomotic dehiscence due to a unique etiology.

Anastomosis, Surgical↗
PubMed2001

Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews.

UNLABELLED: Systematic reviews are structured reviews that use scientific strategies to reduce bias in the collection, appraisal, and interpretation of relevant studies. We undertook a systematic review of published systematic reviews in perioperative medicine to summarize the areas currently covered by this type of literature, to evaluate the quality of systematic reviews in this field, and to assess some of the methodologic and reporting issues that are unique to systematic reviews. Computerized bibliographic databases, citation review, and hand searches were performed to identify eligible articles. Quality was assessed using the Overview Quality Assessment Questionnaire. Eight-two systematic reviews were found. Reviews in perioperative medicine tended to evaluate prophylactic or therapeutic interventions. No differences were seen in quality between reviews published in anesthesia and nonanesthesia journals. Nearly half of all systematic reviews had only minor or minimal flaws; however, methods can be improved with expanded search strategies, use of least two reviewers to assess each study, use of validated methods to evaluate quality, and assessment of potential sources of bias. IMPLICATIONS: The quality of systematic reviews relating to perioperative medicine was examined systematically and found to be similar in quality to those in other specialties. Adoption of recently published criteria on writing and methods could further improve this type of literature.

Anesthesia↗
PubMed2001

The neurologic and adaptive capacity score is not a reliable method of newborn evaluation.

BACKGROUND: The Neurologic and Adaptive Capacity Score (NACS) is a multi-item scale that was published in 1982 to measure the effects of intrapartum drugs on the neonate. Although this scoring system has been widely used in obstetric anesthesia research, studies confirming its reliability have not been published. The purpose of this study was to assess the reliability of the NACS. METHODS: Two teams of observers were trained to perform the NACS on healthy, term neonates born in the vertex presentation. Two examinations were performed on each neonate within the first 2.5 h of life. Simultaneous (or "split-half") reliability was assessed using the alpha coefficient. Test-retest reliability was assessed using the intraclass correlation coefficient. The test was considered to be reliable if a was greater than 0.7 and the intraclass correlation coefficient was greater than 0.6. RESULTS: Two hundred babies were studied. The a was 0.47 and the intraclass correlation coefficient was 0.38 (95% confidence interval, 0.24-0.52). CONCLUSIONS: The NACS had poor reliability both on simultaneous testing and in the test-retest situation when used to evaluate term, healthy neonates. The authors suggest that other measures need to be developed to evaluate the effect of intrapartum drug administration in the neonate. Health measurement scales should undergo rigorous assessment for reliability and validity before they are used in clinical practice or for research purposes.

Adult↗
PubMed2001

Mutations of the cystic fibrosis gene in patients with chronic pancreatitis.

OBJECTIVE: Several studies have reported an increased frequency of cystic fibrosis gene mutations in idiopathic but not in alcoholic chronic pancreatitis. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis has not been analyzed. The aim of our study was to determine the frequency of cystic fibrosis gene mutations in patients with chronic pancreatitis with long-term follow-up and to see whether patients with mutations have a clinically different natural course compared to those without mutations. METHODS: Eighty two patients with chronic pancreatitis and 11 patients with recurrent acute pancreatitis of our well defined pancreatitis cohort were screened for the 31 most common cystic fibrosis gene mutations. The impact of cystic fibrosis gene mutations on the long-term course of chronic pancreatitis was assessed. RESULTS: A cystic fibrosis gene mutation was detected in five of 49 patients with alcoholic chronic pancreatitis (10.2%; 2.3 times the expected frequency) and in three of 14 patients with idiopathic-juvenile chronic pancreatitis (21.4%; 4.8 times the expected frequency). No mutations were found in the remaining patients with chronic pancreatitis of rare causes, hereditary pancreatitis, and recurrent acute pancreatitis. The frequency of pancreatic calcifications was significantly higher in patients with alcoholic chronic pancreatitis without mutations. This result was not confirmed in patients with idiopathic-juvenile chronic pancreatitis. The duration of pain and the frequency of exocrine and endocrine insufficiency was comparable in both subgroups irrespective of the mutation status. CONCLUSION: Our data indicate a significantly increased frequency of cystic fibrosis gene mutations both in patients with alcoholic and idiopathic-juvenile chronic pancreatitis. The natural course was similar in patients with mutations compared to those without mutations.

Adult↗
PubMed2001

Localization of c-Myb and induction of apoptosis by antisense oligonucleotide c-Myb after angioplasty of porcine coronary arteries.

Previous studies have shown that inhibition of the proto-oncogene c-myb inhibits neointimal formation in various animal models. However, the temporal and spatial expression of c-Myb in the vessel wall after injury is not known, and the mechanism of action of antisense oligonucleotide (AS-ODN-c-myb) inhibition remains unclear. One potential effect of cell cycle dysregulation by inhibition of c-myb is an increase in the rates of apoptosis. In this study, c-Myb expression after percutaneous transluminal coronary angioplasty (PTCA) injury and induction of apoptosis after AS-ODN-c-myb treatment were determined. Immunohistochemistry and cellular phenotyping were used to localize c-Myb expression in porcine coronary arteries at various time intervals after PTCA. In vitro, the effects of AS-ODN-c-myb on the apoptosis of porcine vascular smooth muscle cells (PVSMCs) and endothelial cells were determined by using a cell-death ELISA and time-lapse video microscopy. In vivo, local delivery of AS-ODN-c-myb was performed after PTCA of pig coronary arteries, and apoptosis was quantified at 6 hours. c-Myb is induced in pig coronary arteries after angioplasty, with maximal expression in inflammatory cells at 18 hours and in vascular smooth muscle cells at 3 to 7 days. In vitro, AS-ODN-c-myb enhanced PVSMCs (6.8+/-0.8% [P=<0.001] versus 0.5% serum) but not endothelial cell apoptosis (1.4+/-0.5% [P=NS] versus 0.5% serum). In vivo, 6 hours after porcine coronary angioplasty and delivery of AS-ODN-c-myb, the proportion of apoptotic cells within the media was 4.2+/-0.8% (PTCA alone), 2.3+/-0.2% (PTCA+vehicle), and 9.0+/-1.1% (PTCA+AS-ODN-c-myb; P<0.05 versus PTCA alone and P<0.01 versus PTCA+saline). c-Myb is expressed after PTCA of pig coronary arteries, and AS-ODN-c-myb induces apoptosis of PVSMCs in vitro and medial cells in vivo.

Angioplasty, Balloon, Coronary↗
PubMed2001

Phosphorylcholine-coated stents in porcine coronary arteries: in vivo assessment of biocompatibility.

AIMS: To examine the angiographic (quantitative coronary angiography), morphometric, light microscopic (LM) (i.e., histology and immunohistochemical staining) and electron microscopic (EM) findings after implantation of phosphorylcholine (PC)-coated compared to uncoated stents in porcine coronary arteries. METHODS: Forty (25 PC-coated, 15 uncoated) divYsio stents were implanted into the coronary arteries of 20 pigs. Quantitative coronary angiography (QCA) was performed pre-stent and post-implantation in fifteen pigs, at 28 days. Two pigs were killed at 5 days (LM and scanning EM), one pig at 14 days (scanning EM) and 17 pigs at 28 days (LM, scanning EM, transmission EM). At 28 days, thirty-two of 34 stented segments excised were formalin-fixed, of which 30 were embedded in resin and sectioned for morphometry and LM. Remaining stents were examined by TEM and SEM. RESULTS: No angiographically occlusive thrombosis occurred in any of the stents. LM at 5 days showed endothelialization of PC-coated and uncoated stents, which was also confirmed by scanning EM at 14 days. At 28 days, QCA and morphometry showed no significant differences between PC-coated and uncoated stents. A few inflammatory cells were seen in both stent types at 5 days but there was no inflammatory or additional tissue reaction to PC-coated compared to uncoated stents at 28 days. CONCLUSIONS: The divYsio stents, with or without PC coating, performed equally well in terms of acute patency, 28-day QCA and morphometry. The PC coating allows a stent to endothelialize normally and is not associated with specific histological changes. The PC coating on the divYsio stent appears biocompatible.

Animals↗
PubMed2001

The effect of laser assisted uvulopalatoplasty on the sense of smell and taste.

AIM: To assess the effect, if any, of Laser Assisted Uvulo Palatoplasty (LAUP) on the sense of smell and taste. MATERIALS AND METHODS: A prospective study examined 33 patients undergoing LAUP for snoring. Significant sinonasal pathology was excluded in all patients by a complete examination including rigid nasal endoscopy. None of the cases had any systemic illness or drug history that was likely to affect the sense of smell or taste. Twenty-eight patients were male and five female. The mean age was 44 years (range, 25-67). Twelve patients (36%) were regular smokers, and eight patients (24%) were ex-smokers all of whom reported a change in smell and taste after stopping. Preoperative assessment utilised a visual analogue score of smell and taste perception, the University of Pennsylvania Smell Identification Test (UPSIT) for the assessment of olfaction (maximum score of 40), and whole mouth testing for solutions of NaCl, sucrose, quinine, citric acid and acetic acid. LAUP technique was standardised for each case and reassessment was performed 3 months postoperatively. RESULTS: Three patients failed to complete the study and were excluded. The mean values for visual analogue score pre and post surgery were 9.1 and 8.9 respectively, which was not significant using Wilcoxon Rank test (P = 0.257). The mean value of the UPSIT scores before surgery were 32.3 (+4.0), range, 24-39, and after surgery 31.2 (+4.3), range 20-37. There was no significant difference in pre and post UPSIT scores (p = 0.068). Whole mouth taste testing had a preoperative mean value of 4.1 and a postoperative value of 4.2. The difference was not statistically significant, Wilcoxon Rank test (p = 0.317). CONCLUSION: In this study there was no significant change in the patients' perception of smell and taste or in their objective measurement following a standardised Laser Assisted Uvulopalatoplasty.

Adult↗
PubMed2001

Conformational study of peptides containing dehydrophenylalanine: helical structures without hydrogen bond.

The conformational behaviour of deltaZPhe has been investigated in the model dipeptide Ac-deltaZPhe-NHMe and in the model tripeptides Ac-X-deltaZPhe-NHMe with X=Gly,Ala,Val,Leu,Abu,Aib and Phe and is found to be quite different. In the model tripeptides with X=Ala,Val,Leu,Abu,Phe the most stable structure corresponds to phi1=-30 degrees, psi1=120 degrees and phi2=psi2=30 degrees. This structure is stabilized by the hydrogen bond formation between C=O of acetyl group and the NH of the amide group, resulting in the formation of a 10-membered ring but not a 3(10) helical structure. In the peptides Ac-Aib-deltaZPhe-NHMe and Ac-(Aib-deltaZPhe)3-NHMe, the helical conformers with phi = +/-30 degrees, psi = +/-60 degrees for Aib residue and phi=psi= +/-30 degrees for deltaZPhe are predicted to be most stable. The computational studies for the positional preferences of deltaZPhe residue in the peptide containing one deltaZPhe and nine Ala residues reveal the formation of a 3(10) helical structure in all the cases with terminal preferences for deltaZPhe. The conformational behaviour of Ac-(deltaZPhe)n-NHMe with n< or =4 is predicted to be very labile. With n > 4, degenerate conformational states with phi,psi values of 0 degrees +/- 90 degrees adopt helical structures which are stabilized by carbonyl-carbonyl interactions and the N-H-pi interactions between the amino group of every deltaZPhe residue with one C-C edge of its own phenyl ring. The results are in agreement with the experimental finding that screw sense of helix for peptides containing deltaZPhe residues is ambiguous in solution. The helical structures stabilized by hydrogen bond formation are found to be at least 3kCalmol(-1) less stable. Conformational studies have also been carried out for the peptide Ac-(deltaEPhe)6-NHMe and the peptide Ac-deltaAla-(deltaZPhe)6-NHMe containing deltaAla residue at the N-terminal. The N-H-pi interactions are absent in peptide Ac-(deltaEPhe)6-NHMe.

Hydrogen Bonding↗