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Biomedical subjects

N Khan

Publications and source records attributed to N Khan.

At least 55 records · Page 3Linked to original sources
PubMed2003

A comparative study of 11C-choline PET and [18F]fluorodeoxyglucose PET in the evaluation of lung cancer.

The purpose of this study was to compare the diagnostic value of 11C-choline positron emission tomography (PET) and [18F]fluorodeoxyglucose (FDG) PET imaging in the detection of primary lung cancer and mediastinal lymph node metastases. Seventeen patients with histologically proven primary lung cancer were examined with both 11C-choline and FDG PET within a week of each study. Lung cancers were analysed visually and semiquantitatively using the ratio of tumour-to-normal radioactivity (T/N ratio) and standardized uptake value (SUV). Mediastinal lymph node metastases were analysed visually. Although both techniques delineated focal lesions with an increase in tracer accumulation in 13 patients, FDG PET identified three additional patients in whom 11C-choline PET did not visualize any lesion. In the detection of lung cancer <2 cm in size, FDG PET provided higher sensitivity (six of seven, 85.7%) than 11C-choline PET (four of seven, 57.1%). The T/N ratio and SUV were significantly higher with FDG PET (T/N ratio, 7.43+/-6.22; SUV, 4.05+/-3.05) than these were with 11C-choline PET (T/N ratio, 2.93+/-1.19; SUV, 2.93+/-0.79) (P<0.001). There was a significant positive correlation between the T/N ratios and SUVs of FDG and 11C-choline. In the assessment of mediastinal lymph node involvement, FDG PET detected lymph node metastases in two patients who were negative on 11C-choline PET, whereas both techniques could not detect tumour involvement in one patient. Both techniques have clinical value for the non-invasive detection of primary lung cancer that is 2 cm or greater in size. However, FDG PET is superior to 11C-choline PET in the detection of lung cancer that is less than 2 cm in diameter and in mediastinal lymph node metastases.

Adenocarcinoma↗
PubMed2003

PET in the follow-up of differentiated thyroid cancer.

Fluorine-18-fluorodeoxyglucose (FDG) PET has become an increasingly important functional imaging modality in clinical oncology. This article will focus primarily on the role of FDG PET during treatment and follow-up of thyroid cancer. The major role of FDG PET is in patients with elevated thyroglobulin (Tg) levels where thyroid cancer tissue does not concentrate radioiodine rendering false-negative results on I-131 scanning. FDG PET imaging takes advantage of the increased uptake of FDG in cancer cells and is sensitive (60-94%) to the detection of recurrent or metastatic cancer in patients who have negative radioiodine scans. The specificity (25-90%) of PET imaging is relatively less than its sensitivity because some inflammatory processes avidly accumulate FDG. PET can fail to localize the tumour sites in some patients with well-differentiated thyroid cancer that retain good iodine ability. This can result the well recognized phenomenon of "flip-flop" depending on the differentiation of the thyroid cancer. Several studies have documented the higher accuracy of PET, compared with other imaging modalities in the evaluation of patients with recurrent or metastatic differentiated thyroid cancer. The value of thyroid stimulating hormone stimulation for FDG PET has recently been reported. Therefore, if available, this method should be considered in all patients of differentiated thyroid cancer with suspected recurrence and/or metastasis.

Fluorodeoxyglucose F18↗
PubMed2003

Factors predicting persistent sputum smear positivity among pulmonary tuberculosis patients 2 months after treatment.

SETTING: Studies have shown that adverse outcomes are more likely in patients showing persistent sputum positivity at the end of 2 months of anti-tuberculosis treatment. OBJECTIVE: To identify simple clinical, microbiological or radiological factors associated with persistent sputum positivity under national programme conditions. DESIGN: Sputum smear-positive pulmonary tuberculosis patients admitted in 2 consecutive years to a referral hospital, and who received standard short-course chemotherapy under direct observation, were reviewed retrospectively. Factors associated with persistent sputum smear positivity were analysed. RESULTS: A total of 514 patients were available for review. Logistic regression analysis showed that age groups 41-60 years and more than 60 years, numerous bacilli on initial sputum smear examination, and presence of multiple cavitary diseases were significant factors associated with persistent sputum positivity at the end of 2 months of treatment (P < 0.0001). CONCLUSIONS: Identification of high risk factors associated with persistent sputum positivity, such as specific age groups, numerous bacilli on initial sputum smear examination, and presence of multiple cavitary diseases, may be helpful in stratifying the patients according to the risk of adverse outcome, thus allowing greater efficiency in resource utilisation.

Adult↗
PubMed2003

Incidence of bony secondary at presentation of breast carcinoma in our region.

Study is conducted to evaluate the incidence of bony secondary and to evaluate the need for routine bone scintigraphy at the time of presentation of breast carcinoma in this region. Of the total 130 patients evaluated by bone scan, sixty (n = 60, 46.15%) had secondary lesion in bone. Among the 54 preoperative patients, all with positive FNAC, twenty (n = 20, 37.03%) had bony metastases. Of the 76 post-operative patients, forty (n = 40, 52.63%) had secondary bone lesions. Single lesion was seen in only five (n = 5, 8.53%) cases. Rest fifty five (n = 55, 91.67%) had multiple bony secondaries. Most of the postoperative cases (n = 40, 52.63%) were invasive/infiltrative duct cell carcinoma. The very high incidence of bony secondary appears to be due to delayed presentation associated with poor socioeconomic condition, ignorance and also shyness. Bony metastases at the time of presentation suggests poor prognosis. As it can affect therapeutic management of these patients, routine bone scintigraphy at the time of presentation of breast carcinoma patients to a tertiary label hospital is proposed, against conflicting conclusion by papers in the developed countries.

Adult↗
PubMed2003

Ongoing trials of cardiac resynchronisation.

Heart failure is an increasingly common and debilitating condition for which pharmacological therapy has, so far, provided only partial relief. Despite medical therapy the overall prognosis remains poor with high rates of sudden death and death from progressive heart failure. Device based therapies offer considerable promise both for the relief of symptoms and for improving prognosis. Cardiac resynchronisation therapy (CRT) has already been shown to improve the symptoms of heart failure when optimal pharmacological therapy (including aggressive diuretic therapy, ACE inhibitors, b-blockers and spironolactone) has failed. Two large trials (CARE-HF and COMPANION) are currently investigating the effects of CRT on morbidity and mortality in patients with heart failure and sinus rhythm who have left ventricular systolic dysfunction and ventricular dyssynchrony. A series of small and medium sized studies are assessing the effects of CRT in patients similar to the above but who also have atrial fibrillation. Other potential indications for CRT that are being explored include heart failure due to left ventricular diastolic function and for the prevention of iatrogenic dyssynchrony caused by conventional pacing. The MADIT-II study suggests a small benefit from routine implantation of defibrillators in patients with heart failure who have a markedly depressed (<30%) ejection fraction due to prior myocardial infarction even in the absence of specific marker of risk for sudden arrhythmic death. Much greater benefit was observed in patients with QRS >150 msec, an ECG marker for cardiac dyssynchrony. The COMPANION trial will not only assess the effects of CRT alone but also the effects of a combined CRT and defibrillator device. Premature over-interpretation of the limited amount of existing data threatens to undermine the evidence that will form the basis of future guidelines and funding decisions. Those involved in trials have an ethical duty to minimise device implantation into patients who have been randomised to the control group (cross-overs). Doctors may have difficulty explaining to patients why they implanted a CRT device should the current trials not show benefit. Patients should be warned that CRT is still an experimental therapy that has not yet been proven to alter outcome substantially.

Defibrillators, Implantable↗
PubMed2002

Pseudorapidity and centrality dependence of the collective flow of charged particles in Au+Au collisions at sqrt[s(NN)]=130 GeV.

This paper describes the measurement of collective flow for charged particles in Au+Au collisions at sqrt[s(NN)]=130 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). The measured azimuthal hit anisotropy is presented over a wide range of pseudorapidity (-5.0<eta<5.3) for the first time at this energy. The result, averaged over momenta and particle species, is observed to reach 7% for peripheral collisions at midrapidity, falling off with centrality and increasing |eta|. These results call into question the common assumption of longitudinal boost invariance over a large region of rapidity in RHIC collisions.

Journal Article↗
PubMed2002

Presentation and management of patients with initial negative 4-vessel cerebral angiography in subarachnoid hemorrhage.

The importance of repeat-angiography in patients with acute subarachnoid hemorrhage (SAH) and initial negative angiography has been reviewed in the light of our patient population (19 patients with initial negative angiography/168 patients with SAH). The type of SAH i.e., nontraumatic perimesencephalic SAH versus focal or generalized non perimesencephalic SAH, as well as the amount and distribution of blood on the initial CT examination are important factors in decision making. 3D-Angio-CT, in 3/5 patients, and MR-angiography (MRA) in 1/5 patients were complementary non-invasive methods to diagnose aneurysms on repeated examinations. Repeat-cerebral angiography confirmed the source of hemorrhage in 3 patients.

Adult↗
PubMed2002

Strategies for surgical management of cerebral aneurysms of special location, size and form--approach, technique and monitoring.

Special strategies are mandatory for optimal surgical management of aneurysms of special location, size and form. Approaches of extradural selective anterior clinoidectomy, partial occipital condylectomy, transpetrosal approach by anterior petrosectomy and supracerebellar transtentorial approach are discussed among them. Furthermore various types of temporary and permanent clipping procedures are discussed along with mention of intraoperative monitoring.

Craniotomy↗
PubMed2002

Surgical prognosis of unruptured cerebral aneurysms. Report of 40 cases in University Hospital Zurich.

A series of 40 patients admitted to University Hospital Zurich (1996-97) with unruptured cerebral aneurysms is reported. Fifty-two aneurysms were treated in 40 operations. The age of surgically treated patients ranged from 31 to 78 year old (mean 53.6). The main locations of the aneurysms were: MCA 21 (40.4%), AcomA 10 (19.2%), ICA (posterior communicating and bifurcation) 6 (11.5%), carotid-ophthalmic segment 4 (7.7%), ACA 4 (7.7%), basilar tip 3 (5.8%), vertebral artery 2 (3.8%). The circumstances of diagnosis were: incidental 15 (37.5%), other cranial lesions 9 (22.5%), symptomatic 8 (20%), multiple aneurysm 8 (20%). The overall outcome of surgery was: good recovery in 39 cases (97.5%), moderately disabled in 1 case (2.5%) who was 56 year-old and had three aneurysms including basilar tip. There was no operative mortality. Though this series has small number of patients, it suggests that location of the aneurysm is an important factor affecting surgical outcome among patient age, the circumstances of the diagnosis, size and location of aneurysm.

Adult↗
PubMed2002

Diastereotopic effect in some N-substituted-3-methyl-4,1-benzoxazepine-2,5-diones.

1H NMR assignment of seven differently N-substituted-3-methyl-4,1-benzoxazepine-2,5-diones (I) revealed that with the exception of allyl, N-methylene protons of the substituents exhibit diastereotopy due to presence of a chiral centre in the heterocyclic ring at C-3. The significant finding is that the methylenes at C-2' in the substituents n-propyl and n-butyl (Id, Ie) also show diastereotopy. However, the one closer to the chiral centre (at C-1') exhibits greater non-equivalence of its protons. The diastereotopic methylene groups reported in this study correspond to the simplest system AB on one hand and as complex as ABMM'X2 or ABMM'X3 on the other. Calculated spectra obtained from assigned set of data for most of the coupled protons were in good agreement with the observed ones.

Magnetic Resonance Spectroscopy↗
PubMed2002

Osteochondritis dissecans of the knee in children. A comparison of MRI and arthroscopic findings.

The treatment of osteochondritis dissecans (OCD) in children and adolescents is determined by the stability of the lesion and the state of the overlying cartilage. MRI has been advocated as an accurate way of assessing and staging such lesions. Our aim was to determine if MRI scans accurately predicted the subsequent arthroscopic findings in adolescents with OCD of the knee. Some authors have suggested that a high signal line behind a fragment on the T2-weighted image indicates the presence of synovial fluid and is a sign of an unstable lesion. More recent reports have suggested that this high signal line is due to the presence of vascular granulation tissue and may represent a healing reaction. We were able to improve the accuracy of MRI for staging the OCD lesion from 45% to 85% by interpreting the high signal T2 line as a predictor of instability only when it was accompanied by a breach in the cartilage on the T1-weighted image. We conclude that MRI can be used to stage OCD lesions accurately and that a high signal line behind the OCD fragment does not always indicate instability. We recommend the use of an MRI classification system which correlates with the arthroscopic findings.

Adolescent↗
PubMed2002

Lack of control of high blood pressure and treatment recommendations in Canada.

BACKGROUND: Hypertension is a major risk factor for death that affects many Canadians, but only 16% of hypertensive Canadians are treated and have their hypertension controlled. While the control rate is very low, the 2001 Canadian Hypertension Recommendations do not recommend that low risk hypertensive patients be started on pharmacotherapy, and pharmacotherapy is not recommended for people for whom there is no demonstrable benefit from randomized, controlled trails. OBJECTIVES: To determine the proportion of hypertensive patients who are appropriately managed according to the 2001 Canadian Hypertension Recommendations. METHODS: Data from the Canadian Heart Health Survey, which surveyed a cross-sectional population (n=23,129) between 1986 and 1992, were used to determine the proportion of nondiabetic hypertensive patients who are managed according to the 2001 Canadian Hypertension Recommendations. Hypertensive patients not recommended to receive pharmacotherapy include those without risk factors and target organ damage, with a diastolic blood pressure of 90 to 99 mmHg and a systolic blood pressure of less than 160 mmHg. People with diastolic blood pressures of less than 90 mmHg who have systolic blood pressures of 140 to 159 mmHg are also not recommended to have pharmacotherapy. Patients prescribed antihypertensive therapy who had blood pressure controlled to less than 140/90 mmHg were assessed as having their hypertension managed appropriately, as were those who were not treated and were not recommended to be prescribed treatment. RESULTS: There were 58,813 (1.7%) hypertensive patients who did not have target organ damage or additional risk factors, and had a systolic blood pressure of less than 160 mmHg and a diastolic blood pressure between 90 and 99 mmHg. Twenty four per cent of hypertensive persons (831,787) had a systolic blood pressure of 140 to 160 mmHg and a diastolic blood pressure of less than 90 mmHg. About 25% (23.6%+1.7%) of hypertensive Canadians in the Canadian Heart Health Survey are not recommended to be prescribed antihypertensive therapy according to the 2001 Canadian Hypertension Recommendations. Sixteen per cent of hypertensive patients were treated and had their blood pressures controlled (blood pressure less than 140/90 mmHg). Therefore, about 41% (ie, 16%+25%) of hypertensive patients are appropriately managed according to the 2001 Canadian Hypertension Recommendations. CONCLUSIONS: The results of the Canadian Heart Health survey indicate that there are a striking number of Canadians with untreated high blood pressure (59%) who probably do not have their hypertension managed according to the 2001 Canadian Hypertension Recommendations. Greater efforts are required to identify people with hypertension, and to ensure that they are managed according to the best available evidence.

Adolescent↗
PubMed2001

Energy dependence of particle multiplicities in central Au+Au collisions.

We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at root square[s(NN)] = 200 GeV. For the 6% most central collisions, we obtain dN(ch)/d(eta)/(/eta/<1) = 650+/-35(syst). Compared to collisions at root square[s(NN)] = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

Journal Article↗
PubMed2001

The relationship between periodontal disease and blood glucose level among type II diabetic patients.

The aim of this study was to determine the relationship between periodontal disease and the blood glucose level among type II non-insulin dependent diabetic mellitus (NIDDM) subjects. Forty subjects, 20 in each group, of healthy and diabetic subjects, ages ranged 20-70 years, were examined at King Saud University, College of Dentistry. Clinical examination included frequency of oral hygiene practices, periodontal status by using the Community Periodontal Index of Treatment Needs (CPITN), fasting blood glucose level (FBGL), and random blood glucose level (RBGL). Unstandardized orthopantomograms (OPGs) were taken for radiographic findings. The number of missing teeth (tooth loss) was assessed from the radiographs. The results showed that periodontal disease severity was high among diabetic subjects. Diabetic subjects brushed less frequently, and they had a higher blood glucose level than healthy subjects. The mean CPITN score was compared with mean blood glucose level and the severity of periodontal disease. There was a steady increase in blood glucose level with increase in CPITN scores, i.e., CPITN score 13.5 to 19.12 corresponded with 142 mg/dl and 173.2 mg/dl FBGL, and 184.2 and 199.12 mg/dl RBGL among diabetic subjects. The study indicated that diabetic subjects should improve their oral hygiene practices and control of blood glucose levels should be emphasized. Further studies are needed among diabetics and healthy subjects from the general population with better sampling techniques and a larger sample size.

Adult↗
PubMed2001

Charged-particle pseudorapidity density distributions from Au+Au collisions at sqrt[s(NN)]=130 GeV.

The charged-particle pseudorapidity density dN(ch)/d eta has been measured for Au+Au collisions at sqrt[s(NN)] = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for /eta/<or=5.4 is found to be 4200+/-470. The evolution of dN(ch)/d eta with centrality is discussed, and compared to model calculations and to data from proton-induced collisions. The data show an enhancement in charged-particle production at midrapidity, while in the fragmentation regions, the results are consistent with expectations from pp and pA scattering.

Journal Article↗
PubMed2001

Ratios of charged antiparticles-to-particles near mid-rapidity in Au + Au collisions at sqrt[s(NN)]=130 GeV.

We have measured the ratios of antiparticles to particles for charged pions, kaons, and protons near mid-rapidity in central Au+Au collisions at sqrt[s(NN)] = 130 GeV. We observe / = 1.00+/-0.01(stat)+/-0.02(syst), / = 0.91+/-0.07(stat)+/-0.06(syst), and / = 0.60+/-0.04(stat)+/-0.06(syst). The / and / ratios give a consistent estimate of the baryo-chemical potential mu(B) of 45 MeV, a factor of 5-6 smaller than in central Pb+Pb collisions at sqrt[s(NN)] = 17.2 GeV.

Journal Article↗
PubMed2001

No pathogenic mutations in the synphilin-1 gene in Parkinson's disease.

alpha-Synuclein is mutated in rare autosomal dominant forms of Parkinson's disease and is a major component of Lewy bodies and neurites. Synphilin-1, a novel protein interacts in vivo and co-localises with alpha-synuclein in Lewy bodies. We analysed the synphilin-1 gene in familial Parkinson's disease by single-strand conformation polymorphism (SSCP) and automated sequencing but found no coding mutations. However, we identified two novel intronic polymorphisms; an A/T polymorphism in intron 2, resulting in the introduction of an Alu1 site and a second G/T polymorphism in intron 4. We analysed the intron 2 polymorphism for allelic association as it was conducive to rapid screening but observed no changes in frequency between Parkinson's disease cases and controls.

Aged↗