PubMed Health⌕ Search

Biomedical subjects

A Hasan

Publications and source records attributed to A Hasan.

At least 19 recordsLinked to original sources
PubMed2006

Acyclic pyrazolo[3,4-d]pyrimidine nucleoside as potential leishmaniostatic agent.

A new synthesis of 6-amino-1-hydroxyethoxymethyl-4 (5H)-oxopyrazolo[3, 4-d]pyrimidine (4) has been mentioned. Compound 4 exhibited inhibition of amastigotes of Leishmania donovani to the extent of 89 % at 30 microg/mL, whereas iso-guanine analogue 5 had the inhibition only to the extent of 52.8% at 100 microg/mL in vitro. In hamster model the maximum inhibitory response for compound 4 against amastigotes multiplication was observed to be 94% at 50 mg/kg single dose for 5 consecutive days.

Animals↗
PubMed2005

Patient attitudes to sternotomy and thoracotomy scars.

BACKGROUND: There are no data comparing patient attitudes to sternotomy and thoracotomy scars following surgery for congenital heart disease (CHD). METHODS: Two hundred and one patients with a scar from CHD surgery (105 sternotomy, 36 thoracotomy, and 60 both scars) had a structured interview to explore attitudes to their scar. RESULTS: Comparable proportions of each group reported that they did not like or hated their scar (23/105 [22 %] sternotomy, 9/36 [25 %] thoracotomy, 17/60 [28 %] both scars). Significantly more patients stated that they where embarrassed by and/or their choice of clothing was affected by a thoracotomy scar (20/36, 56 %) than those with a sternotomy scar (36/105, 34 %), p = 0.04. This was also seen when comparing sternotomy alone with both scars (36/105 [34 %] vs. 34/60 [57 %], p = 0.008). CONCLUSIONS: Adults who have undergone surgery for CHD are more likely to have a negative attitude to a thoracotomy than a sternotomy scar. Before a change in surgical approach is considered based on patient preferences, the acceptability and psychological impact of the different scars following surgery needs formal study.

Adult↗
PubMed2005

The immune responses to human and microbial heat shock proteins in periodontal disease with and without coronary heart disease.

The human 60 kDa and microbial 65 kDa heat shock proteins (HSP) have been implicated in the pathogenesis of chronic periodontitis (P) and coronary heart disease (CHD). We have studied four male non-smoking cohorts of 81 subjects, matched for age. Group (a) consisted of a healthy group with minimal gingivitis (n = 18), group (b) were patients with P (n = 23), group (c) patients with CHD and minimal gingivitis (n = 20) and group (d) patients with CHD and P (n = 20). T cells separated from peripheral blood were found to be primed to both microbial HSP65 and human HSP60 but significant CD4, human leucocyte antigen (HLA) class II-restricted proliferative responses were found only with the human HSP60 in patients with P (P < 0.001) and CHD without (P < 0.001) or with (P < 0.00001) periodontitis. Dose-dependent inhibition of T cell proliferative responses was carried out to determine the receptors involved in recognition of HSP60 and HSP65. Monoclonal antibodies to CD14 showed inhibition of T cell proliferation stimulated by both HSP60 and HSP65, consistent with the role of CD14 as a receptor for these HSPs in P and CHD. The toll-like receptor 2 (TLR-) and TLR-4 were then studied and these showed that TLR-4 was recognized by microbial HSP65, whereas TLR-2 was recognised by human HSP60 in both P and CHD. However, a dissociation was found in the HSP60 and TLR4 interaction, as TLR4 appeared to have been recognized by HSP60 in P but not in CHD. The results suggest an autoimmune or cross-reactive CD4(+) class II-restricted T cell response to the human HSP60 in P and CHD. Further studies are required to determine if there is a common epitope within HSP60 that stimulates T cell proliferation in P and CHD.

Adult↗
PubMed2005

Cross-reactivity of GroEL antibodies with human heat shock protein 60 and quantification of pathogens in atherosclerosis.

BACKGROUND/AIMS: Chronic infections such as those caused by Chlamydia pneumoniae and periodontopathic bacteria such as Porphyromonas gingivalis have been associated with atherosclerosis, possibly due to cross-reactivity of the immune response to bacterial GroEL with human heat shock protein (hHSP) 60. METHODS: We examined the cross-reactivity of anti-GroEL and anti-P. gingivalis antibodies with hHSP60 in atherosclerosis patients and quantified a panel of six pathogens in atheromas. RESULTS: After absorption of plasma samples with hHSP60, there were variable reductions in the levels of anti-GroEL and anti-P. gingivalis antibodies, suggesting that these antibodies cross-reacted with hHSP60. All of the artery specimens were positive for P. gingivalis. Fusobacterium nucleatum, Tannerella forsythia, C. pneumoniae, Helicobacter pylori, and Haemophilus influenzae were found in 84%, 48%, 28%, 4%, and 4% of arteries, respectively. The prevalence of the three periodontopathic microorganisms, P. gingivalis, F. nucleatum and T. forsythia, was significantly higher than that of the remaining three microorganisms. CONCLUSIONS: These results support the hypothesis that in some patients, cross-reactivity of the immune response to bacterial HSPs including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may be a possible mechanism for the association between atherosclerosis and periodontal infection.

Aged↗
PubMed2004

Life insurance and mortgage application in adults with congenital heart disease.

OBJECTIVE: To compare the outcome of life insurance and mortgage applications of adults with congenital heart disease (CHD) with controls and at different severities of CHD. METHODS: Two hundred and ninety-nine adult CHD patients underwent a questionnaire-based interview by a trained nurse. They were asked to give an identical questionnaire to a friend to act as a control. One hundred and seventy-seven controls replied. CHD patients were classified into three categories based on severity. Comparisons were made between matched controls and between different severities of CHD. RESULTS: Similar proportions of the CHD group (59%) had applied for life insurance as matched controls (56%). Compared to controls, significantly more of the adults with CHD who had applied for life insurance have been refused (34 vs 4%, P < 0.0001) or asked to pay extra (37 vs 6%, P = 0.0002). Mortgage application rate was also similar in both groups with more of the CHD patients refused than matched controls (20 vs 3%, P = 0.0004). These differences in both life insurance and mortgage remain significant when the cases and controls are matched by employment status and NYHA functional class. There was no significant difference in life insurance and mortgage application outcome between the groups of mild, significant and complex CHD. CONCLUSIONS: Adults with CHD are significantly more likely to have difficulty obtaining life insurance or a mortgage than controls. Refusal rates appear to be independent of the severity of CHD. This suggests that the label of CHD may have a negative impact despite the lesion being minor and that the outcome of an individual application is difficult to predict based on the severity of the CHD. The increasing numbers of adults with CHD suggest that this problem is likely to increase and needs to be addressed as it can have a major impact on the patient's quality of life.

Adult↗
PubMed2003

Management of transfusion-related acute lung injury with extracorporeal cardiopulmonary support in a four-year-old child.

We report a case of successful management of transfusion-related acute lung injury (TRALI) with prolonged cardiopulmonary bypass support in a 4-yr-old patient undergoing elective cardiac surgery. TRALI was diagnosed clinically and immunologically by detection of reactive antibodies in a unit of fresh frozen plasma that had been administered to the patient. The aetiology and management of TRALI are briefly discussed and possible implications of this case for the management of TRALI are highlighted.

Cardiopulmonary Bypass↗
PubMed2003

Ischemic stroke subtypes in Pakistan: the Aga Khan University Stroke Data Bank.

OBJECTIVE: Frequency of ischemic stroke subtypes is influenced by ethnic and geographic variables. Our objective was to identify various stroke subtypes and its determinants at a tertiary care hospital. METHODS: We prospectively collected data on ischemic stroke subtypes admitted to The Aga Khan University Hospital in Karachi. RESULTS: A total of 596 patients were enrolled in 22 months in the Aga Khan Universtiy Stroke Registry. These included 393 patients with Ischemic stroke, 126 patients with intracerebral hemorrhage, 50 patients with subarachnoid hemorrhage and others. The ischemic stroke group was classified according to the TOAST criteria and comprised of lacunar 168/393 (42.7%); large artery atherosclerosis 106/393 (26.9%); cardioembolic 24/393 (6.1%); undetermined 80/393 (20.3%); and other determined types 15/393 (3.8%). The high proportion of lacunar strokes in our population may be due to high burden of inadequately treated hypertension and diabetes. Clear cut cardioembolic stroke was relatively infrequent in our population. CONCLUSION: Lacunar stroke is the most common subtype of stroke in our patient population. This is most likely secondary to uncontrolled hypertension.

Adult↗
PubMed2002

Experimental research photodynamic effects in perifocal, oedematous brain tissue.

BACKGROUND: Photodynamic therapy (PDT) has been under discussion as additional treatment option for malignant gliomas. However, damage not only to tumour tissue but also to normal brain has been demonstrated. The mechanisms of this unwanted side effect have not yet been clearly identified. Spreading of photosensitiser with oedema after disruption of the blood-brain-barrier and potential sensitisation of normal tissue has been found previously. The present study investigates the time- and dose-dependency of normal tissue damage to photodynamic therapy using Photofrin II after disruption of the blood-brain-barrier. METHODS: Male wistar rats anaesthetised with chloral hydrate were subjected to focal, cerebral cold lesions. Simultaneously, Photofrin II (PFII) was injected (2,5 or 5 mg/kg b.w.). Laser irradiation (630 nm) was performed after 4 h, 12 h and 24 h with varying light doses. Control groups were subjected to focal cold lesion alone, cold lesion with laser irradiation, PFII followed by laser irradiation, or laser irradiation alone (n=6 all groups). 24 h later, brains were removed for assessment of necrosis in coronal sections. FINDINGS: Light dose had a significant impact on the extent of necrosis. Compared to control animals (lesion only: 0.84 +/- 0.2 mm2; lesion and irradiation alone: 0.7 +/- 0.3 mm2), the area of necrosis was increased to 2.8 +/- 0.5 (50 J/cm2), 3.5 +/- 1,1 (100 J/cm2) and 4.3 +/- 0.7 mm2 (200 J/cm2, 5 mg/kg b.w.; p<0.01). This effect was time-dependent. Maximal necrosis (6.3 +/- 1,6 mm2) was observed when brains were irradiated 12 h after PFII injection, with less necrosis occurring at 24 h (2.8 +/- 0.4 mm2, p<0.01). Reducing sensitiser dose to 2.5 mg/kg b.w. resulted in a reduction of necrosis (2.09 +/- 0.2 mm2, p<0.05). INTERPRETATIONS: Damage to oedematous tissue after photodynamic therapy using i.v. PFII and laser light at 630 nm depends on laser dose, sensitiser dose and the time point of laser irradiation. The time point of PDT should be considered to prevent unwanted tissue reactions. In the clinical setting however, defined damage to peritumoural tissue may be advantageous. This should be achievable by optimised timing and dosage of photodynamic therapy.

Animals↗
PubMed2002

Defining a T-cell epitope within HSP 65 in recurrent aphthous stomatitis.

The 65 kD heat shock protein (HSP) has been implicated in the aetiology of recurrent aphthous stomatitis (RAS). We have previously demonstrated that peptide 91-105 derived from the sequence of mycobacterial 65 kD HSP stimulates specifically lymphocytes from patients with RAS. In this investigation, we show that both CD4+ and CD8+ T cells were significantly stimulated with mycobacterial peptide 91-105. In contrast, the human homologous peptide 116-130 stimulated only CD4+ T cells. Inhibition studies showed that CD4+ T cells were class II restricted, whereas CD8+ T cells were class I restricted. We then used truncated or substituted peptides, and demonstrated that residues 95-105 appear to be important, and residue 104(Arg) critical, in stimulating the T cells. Thus, peptide 95- 105 may constitute a T-cell proliferative epitope in RAS. We postulate that the high load of micro-organisms that colonize the oral mucosa may initiate an immune response by the microbial HSP 65-derived peptide 95-105, stimulating the numerous Langerhans cells in the oral mucosa to activate a cross-reacting immune response to the homologous peptide 116-130 within the epithelial HSP 60, initiating the immunopathological changes that lead to RAS.

Adult↗
PubMed2001

Hormonal control of arylhydrocarbon receptor (AhR) expression in the preimplantation rabbit uterus.

We show that the arylhydrocarbon receptor (AhR) is localised in a distinct pattern in the preimplantation rabbit uterus. Employing immunohistochemistry, uteri from mature and immature rabbits were studied in different pregnancy stages during the preimplantation period (non-pregnant/estrous, pregnant and pseudopregnant) and following treatment with estradiol and progesterone, respectively. The staining patterns in pregnant and pseudopregnant rabbits were similar, indicating a primary maternal control of expression. A distinct change in AhR localization occurred in the endometrium of (1) non-pregnant compared with pregnant rabbits and (2) shortly prior to the anticipated time of implantation. Compared with non-pregnant uteri, the AhR was no longer restricted to a small cytoplasmic area apical to the nucleus but was found in the entire cytoplasm and in the nuclei of the endometrial epithelial cells in pregnant uteri. Prior to implantation, at day 6, stromal cells and the epithelium of the uterine glands, but no longer the luminal epithelial cells, were immunopositive. The estradiol-treated immature uteri showed a strong expression in the luminal epithelium and in some uterine glands, often with nuclear staining, while the estradiol-primed and progesterone-treated specimens had a similar staining pattern as mature preimplantation uteri. Present results demonstrate a distinct localization pattern of the AhR in the endometrium during the preimplantation period. Stage-specific changes in the expression pattern indicate control of AhR expression by maternal steroid hormones.

Animals↗
PubMed2001

A policy of elective delayed sternal closure does not improve the outcome after arterial switch.

BACKGROUND: Delayed sternal closure is regularly used in the immediate management of hemodynamic instability after neonatal cardiac procedures. The aim of this study was to assess whether the routine, elective use of delayed sternal closure would reduce morbidity in neonates undergoing arterial switch for transposition of the great arteries. METHODS: A retrospective statistical analysis was performed on 52 neonates operated on from 1991 to 1998. Until 1994, chest closure was routinely attempted in all patients after arterial switch; the policy was then changed to delayed sternal closure in all cases in the latter half of the study period. RESULTS: Delayed sternal closure did not significantly alter the mean duration of ventilation (2.7 +/- 2.37 versus 2.7 +/- 1.3 days) nor intensive care stay (4.1 +/- 2.8 versus 5.7 +/- 10.0 days; p = 0.46). There was no increase in the incidence of wound sepsis (7.7% versus 3.8%; p = 0.55), and mortality was unchanged (7.7% in both groups). There was an increase in the incidence of urgent reexploration (7.7% versus 19.2%; p = 0.22), which did not reach significance. CONCLUSIONS: This study does not support the hypothesis that elective delayed sternal closure reduces the morbidity after arterial switch in neonates but does, however, confirm the safety and efficacy of the procedure.

Female↗
PubMed2001

A dual strategic approach to mega-aortic aneurysms.

Staged resection of mega-aortas with Borst's two-stage elephant trunk (ETK) is the gold standard but has a higher mortality and morbidity compared to single-segment repair. We report the first case of combined surgical and covered-stent approach in Europe. Location and dilatation of the proximal landing zone accounts for the majority of failures in covered-stenting but an ETK is stable, easy to localise and gives an excellent seal. In high-risk cases where surgical resection is not offered, stenting is an option. The lack of a thoracotomy is an advantage in often-frail patients recovering from stage-I and shortens ITU-stay. Therefore, a combined approach is an acceptable alternative in selected individuals.

Aged↗
PubMed2001

Anomalous left coronary artery from the pulmonary artery: creating an autogenous arterial conduit for aortic implantation.

Anomalous origin of the left coronary artery from the pulmonary artery requires surgical correction. A surgical technique is presented. Two infants underwent re-implantation of their anomalous left coronary arteries by creating a tunnel using autogenous aortic and pulmonary arterial walls. The advantage of this technique is that the new left coronary artery lies in the horizontal plane and in an anatomically correct axis running in the groove behind the pulmonary artery. It also provides a tension free endothelialized autogenous arterial walls with normal growth anticipated.

Aorta, Thoracic↗