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Biomedical subjects

N Iqbal

Publications and source records attributed to N Iqbal.

At least 19 recordsLinked to original sources
PubMed2006

Mutagenic effect of acridine orange on the expression of penicillin G acylase and beta-lactamase in Escherichia coli.

AIMS: The present work aimed to improve the production of penicillin G acylase (PGA) and reduce the beta-lactamase activity through acridine orange (AO) induced mutation in Escherichia coli. METHODS AND RESULTS: Three wild E. coli strains BDCS-N-FMu10, BDCS-N-S21 and BDCS-N-W50, producing both the enzymes PGA and beta-lactamase were treated by AO. Minimum inhibitory concentration of AO was 10 microg ml(-1) and it was noted that bacterial growth was gradually suppressed by increasing the concentration of AO from 10 to 100 microg ml(-1). The highest concentration that gave permissible growth rate was 50 microg ml(-1). The isolated survivals were screened on the bases of PGA and beta-lactamase activities. Among the retained mutants, the occurrence of beta-lactamase deficient ones (91%) was significantly higher than penicillin acylase deficient ones (27%). CONCLUSIONS: In seven of the mutants, PGA activity was enhanced with considerable decrease in beta-lactamase activity. One of the mutant strains (BDCS-N-M36) exhibited very negligible expression of beta-lactamase activity and twofold increase in PGA activity [12.7 mg 6-amino-penicillanic acid (6-APA) h(-1) mg(-1) wet cells] compared with that in the wild-type strain (6.3 mg 6-APA h(-1) mg(-1) wet cells). SIGNIFICANCE AND IMPACT OF THE STUDY: The treatment of E. coli cells with AO resulted in mutants with enhanced production of PGA and inactivation of beta-lactamase. These mutants could be used for industrial production of PGA.

Acridine Orange↗
PubMed2005

Pancreaticothoracic fistulas: imaging findings in five patients.

BACKGROUND: Pancreaticothoracic fistulas are a rare complication of chronic pancreatitis. This study evaluated the imaging findings in patients with pancreaticothoracic fistulas. METHODS: We retrospectively reviewed the medical records and radiographic images in five patients with pancreaticothoracic fistulas diagnosed at our institution during the previous 6 years. Data from radiography, endoscopic retrograde cholangiopancreatography (ERCP), computed tomography (CT), magnetic resonance cholangiopancreatography, and drainage catheter studies were evaluated. RESULTS: Persistent pleural effusions were present on the radiographs of all patients. ERCP was performed in three patients. Contrast material was injected into drainage catheters placed in a pancreatic pseudocyst in one patient and a pancreatic abscess in another patient. Pancreaticothoracic fistulas were demonstrated on all of these studies. One patient had a CT study immediately after ERCP and another patient had a CT study immediately after contrast material was injected through a drainage catheter placed percutaneously in a pseudocyst. CT demonstrated the full extent of the pancreaticothoracic fistula in both patients. CONCLUSION: Pancreaticothoracic fistulas are rare and may require multiple imaging modalities to establish a diagnosis.

Adult↗
PubMed2004

Management of blunt renal trauma: a profile of 65 patients.

OBJECTIVE: To outline the pattern and trends in the management of patients of renal trauma at the Department of Urology and Renal Transplantation, Jinnah Hospital, Lahore, from January 1998 to June 2003. METHODS: We retrospectively reviewed 65 patients identified with blunt renal trauma. RESULTS: Of 65 patients of renal trauma, injuries were graded I to V in 18 (27%), 9 (14%), 13 (20%), 16 (24%) and 9 (14%) respectively. Nephrectomy was done in all patients of Grade V and in 3 patients of Grade IV injury. Two patients in each group of grade IV and V died of associated injury. Rest of the patients were treated conservatively with blood transfusion, parenteral fluid, antibiotics, analgesics and bed rest. Of 53 patients treated conservatively two (4%) developed fever and eight (15%) hypertension. Two (4%) patients of grade III underwent delayed exploration for perinephric collection. CONCLUSION: Conservative management of blunt renal trauma without associated abdominal injury is feasible in patients who are hemodynamically stable at presentation.

Adolescent↗
PubMed2002

Comparative double-blind randomized placebo-controlled clinical trial of a herbal eye drop formulation (Qatoor Ramad) of Unani medicine in conjunctivitis.

Qatoor Ramad (QR) is an ophthalmic formulation of Unani medicine. It is reputed for its beneficial effects in the treatment of the inflammatory conditions of the eyes. The effect of QR eye drops was studied by a double-blind, randomized, prospective, placebo-controlled clinical trial, conducted in 70 patients (20-60 yrs) suffering from different types of conjunctivitis, namely mucopurulent, phlyctenular and allergic conjunctivitis. Local application of two drops (3-4 times/day) of QR was applied to the affected eyes for up to 14 days. Patients were examined at the time of diagnosis and after 2, 7 and 14 days. Clinical efficacy was measured as the cumulative sum score of several signs and symptoms of different types of conjunctivitis. Side effects, if any, were also noted during the study. In mucopurulent conjunctivitis QR showed excellent results. In the few cases of phlyctenular and allergic conjunctivitis it controlled the deterioration and seems to help in improvement. There were no side effects observed during the course of the study and the eye drop was well tolerated by the patients. It is considered to be a useful drug in all conditions studied.

Adult↗
PubMed2001

Immuno-bacterial homeostasis in the gut: new insights into an old enigma.

The intestinal mucosa is the interface between the immune system and the massive antigenic load represented by the commensal enteric bacteria. These commensal bacteria drive the development of the mucosal immune system, and in turn most of the lymphocytes in the intestinal mucosa appear to be specific for enteric bacteria antigens. Proper regulation of the responses of these anti-bacterial lymphocytes are extremely important because T cell effectors reactive to enteric bacterial antigens have been shown to cause chronic intestinal inflammation in an adoptive transfer system. The cells and molecules important in regulating mucosal immune response are now being identified. Insights into the mechanisms of mucosal regulation have come from a number of genetically manipulated mouse strains which develop inflammatory bowel disease in response to the enteric bacterial flora. CD4(+)T cells with regulatory function in the mucosa are being identified; other cell types such as CD8(+)T cells. NK cells, and B cells may also have a role in mucosal immune regulation. A model for T cell-immune homeostasis in the intestinal mucosa is presented.

Animals↗
PubMed2001

Nephrolithiasis during pregnancy secondary to primary hyperparathyroidism.

Nephrolithiasis secondary to primary hyperparathyroidism infrequently complicates pregnancy. It can cause severe maternal and fetal complications. We present a case of a pregnant woman with nephrolithiasis and primary hyperparathyroidism. We reviewed the management of nephrolithiasis due to primary hyperparathyroidism during pregnancy. We believe that early recognition and timely intervention can significantly reduce the incidence of complications.

Adult↗
PubMed2001

Imaging of the ductus venosus in neonates: from patency to closure.

OBJECTIVE: To familiarize the radiologist with the variable sonographic appearance of the involuting ductus venosus in neonates. METHODS: Five sick neonates ranging in age from 24 to 42 weeks had abdominal sonographic examinations to check for intra-abdominal diseases. RESULTS: Doppler sonography showed a patent ductus venosus in 3 neonates and a ductus venosus with thrombosis in 2 neonates. The ductus venosus was identified in the liver between the left portal vein and the inferior vena cava. In 2 patients, follow-up sonography showed that the ductus venosus progressively had thrombosis and then disappeared. CONCLUSIONS: The ductus venosus in a neonate has a variable sonographic appearance depending on its stage of involution. Its detection in a sick neonate can lead to inadvertent diagnosis of a hepatic varix, an abscess, or a tumor.

Heart Defects, Congenital↗
PubMed2001

The skin we are in--knowledge and practices regarding skin cancer in pre-clinical medical students.

OBJECTIVE: To assess the level of knowledge about skin cancer in youth and to explore the influence of gender and system of education on their knowledge and practices. MATERIALS AND METHODS: A questionnaire-based study was conducted at The Aga Khan University Medical College (AKUMC), on Year 2 pre-clinical medical students. Descriptive analyses to examine the frequency distribution, chi-square test and factor analysis were applied using SPSS. RESULTS: Seventyone students participated in the study; 90% scored > 55% in the questions regarding knowledge of Malignant melanoma (MM), whereas in the questions assessing practice only 11% of the respondents scored > 52%. They were largely unaware that appearance of a new mole is a risk factor for MM (56% respondents incorrect) and that skin cancer is one of the most common cancers (54% respondents incorrect). 73% reported being sunburned at least once during childhood and 40% suffered sunburns at least once this summer, which points to the inadequacy of sun protection. The risk of MM may double if severe sunburns are experienced during childhood. Education system and gender did not affect the knowledge and practices. The popular sources of learning about skin cancer were magazines (52%) followed by television (42%). CONCLUSION: There is a need for epidemiological studies in Pakistani population regarding skin cancer. For preventing excessive solar exposure which leads to sunburns, we recommend interventions like a Pilot Program for photoprotection education and Sun Awareness Week to improve knowledge and sun protection behavior.

Adolescent↗
PubMed2000

Evaluation of methylthio-, methylsulfinyl-, and methylsulfonyl-analogs of alkanes and alkanoic acids as cardiac inotropic and antifungal agents.

A group of alkane and alkanoic acid compounds of general formula MeS(O)m(CH2)nR [m = 0-2; n = 1, 5, 13; R = Me, CO2H(Na)] were synthesized for evaluation as cardiac inotropic and antifungal agents. Inotropic activity was determined as the ability of the test compound to modulate in vitro guinea pig atrium contractility. The oxidation state of the S-atom was an important determinant of inotropic modulation since the thio (m = 0) analogs exhibited a positive inotropic effect. In contrast, the sulfinyl (m = 1) and sulfonyl (m = 2) analogs exhibited a negative inotropic effect. A pentyl spacer (n = 5) provided the largest positive or negative inotropic effect. The relative positive, and negative, inotropic potency orders with respect to the R-substituent were Me > or = CO2H, and CO2Na > or = Me, respectively. The most potent positive inotrope MeS(CH2)5Me (EC50 = 4.49 x 10(-6) M) could serve as a useful lead-compound for the design of a new class of positive inotropic agents. In a broad spectrum antifungal screen, the minimal inhibitory concentration (MIC) range for the five most active compounds was MeSO2(CH2)5Me (0.46-1.83 mM), MeS(CH2)13Me (0.31-1.23 mM), MeSO(CH2)13Me (< 0.009-1.87 mM), MeSO2(CH2)13Me (0.27-1.09 mM), and MeS(CH2)13CO2H (0.27-1.09 mM), relative to the reference drug Ampotericin B (< 0.0002-0.002 mM). The most active antifungal agent MeSO(CH2)13Me was selective against C. guillermondi, C. neoformans, S. cerevisiae, and A. fumigatus (strain TIMM 1776).

Alkanes↗
PubMed2000

The production and characterization of recombination between chromosome 3N of Aegilops uniaristata and chromosome 3A of wheat.

Six wheat lines with recombination between Aegilops uniaristata chromosome 3N and wheat chromosome 3A were produced. These were characterized in terms of exchange points by RFLP analysis. Chromosome 3N carries an undesirable brittle rachis gene and three of the recombinant lines had lost this character. The results also support previously published evidence of a pericentric inversion in chromosome 3N relative to the wheat homoeologous group 3 chromosomes.

Chromosomes↗
PubMed2000

Diagnosis of gastrointestinal graft-versus-host disease.

Allogeneic bone marrow transplantation is becoming increasingly performed for a variety of disorders but primarily for hematological malignancies. Graft-versus-host disease (GVHD), which often involves the GI tract, is one of the most common complications of this type of transplantation. The diagnosis of GI GVHD can be difficult to establish because of the nonspecific nature of associated symptoms, few diagnostic endoscopic findings, and potential difficulty in making a histological diagnosis. In this review, we summarize current concepts and controversies regarding the diagnostic evaluation for GI GVHD.

Biopsy↗
PubMed2000

Thalidomide impairs insulin action on glucose uptake and glycogen synthesis in patients with type 2 diabetes.

OBJECTIVE: To investigate the effect of thalidomide on glucose turnover (glucose production and uptake), on intracellular pathways of glucose utilization (glycogen synthesis [GS], glycolysis [GLS], carbohydrate oxidation, and nonoxidative GLS), and on free fatty acid (FFA) turnover (lipolysis, FFA oxidation, and FFA reesterification). RESEARCH DESIGN AND METHODS: A total of 6 patients with type 2 diabetes were studied with 4-h isoglycemic-hyperinsulinemic clamps (approximately 8 mmol/l and 500-600 pmol/l, respectively) before treatment (Prestudy), after 3 weeks of thalidomide (150 mg orally at bedtime), and after 3 weeks of placebo. RESULTS: Thalidomide reduced insulin-stimulated glucose uptake by 31% (from 27.7 to 19.2 pmol x kg(-1) x min(-1), P < 0.05) compared with the prestudy and by 21% (from 24.2 to 19.2 pmol x kg(-1) x min(-1), P < 0.05) compared with placebo. Thalidomide also reduced insulin-stimulated GS by 48% (from 14.1 to 8.2 micromol x kg(-1) x min(-1), P < 0.05) compared with the prestudy and by 40% (from 13.6 to 8.2 micromol x kg(-1) x min(-1), P < 0.5) compared with placebo. Thalidomide had no effect on rates of GLS, carbohydrate oxidation, nonoxidative GLS, lipolysis, FFA oxidation, and reesterification. CONCLUSIONS: We conclude that thalidomide increased insulin resistance in obese patients with type 2 diabetes by inhibiting insulin-stimulated GS and that patients taking thalidomide should be monitored for possible deterioration in their glucose tolerance.

Blood Glucose↗
PubMed2000

Substance dependence. A hospital based survey.

OBJECTIVE: To collect basic data on multiple and diverse issues such as drugs of dependence, smoking, initiation age, injection related harm, nutritional status, trauma, accidents, abnormal laboratory parameters and co-morbid conditions. METHOD: Seven hundred and ninety nine subjects from a voluntary detoxification unit were studied. Four hundred and ninety seven charts from June 1995 to December 1995 were reviewed retrospectively. For the other 302 subjects admitted between September 1996 to December 1996, information regarding drug use, smoking, trauma, accidents and co-morbid conditions was recorded during the admission interview while the remaining data was later obtained from the charts. RESULTS: Sixty eight percent were under 35. Ninety seven percent were smokers and 55% started smoking before the age of 15. Sixty four percent initiated drugs before the age of 25 while 34% had been on drugs for less than 5 years. Eighty seven percent were using heroin or alcohol. Fourteen percent were dependent on more than one drug. Among heroin users 91% were injecting, 21% had injection related complications, 69% had Hepatitis C Virus and 0.40% died. Forty four percent had at least one current medical disorder, 59% had one abnormal laboratory parameter and 21% below normal Body Mass Index. Nine percent had mental disorders and 1% presented with overdose. Twenty nine percent reported unintentional injuries and 12% reported of road traffic accidents. Seventeen point five percent had family history of drug use, 4.5% had mental disorders and 87% physical disorders. CONCLUSION: More accurate and reliable data is required. Current services need to be improved. Preventative measures should focus on early detection and intervention and a central body for information collection should be established.

Accidents↗
PubMed1999

Contribution of psychosis and depression to behavioral disturbances in geropsychiatric inpatients with dementia.

BACKGROUND: Specific behavioral disturbances in dementia may be associated with underlying disorders such as the presence of psychosis and depression. The objective of this study was to examine the association of depression and psychosis with behavioral disturbances in geropsychiatric inpatients with dementia. METHODS: All admissions between October 1993 and May 1995 were reviewed to identify those patients admitted to the Houston Veterans Affairs Geropsychiatry Unit with a diagnosis of dementia; 208 patients were included in the study. Hierarchical regression models were constructed to explore the contribution of depressive and psychotic symptoms, and depression and psychosis diagnoses to Cohen-Mansfield Agitation Inventory (CMAI) scores. RESULTS: Both depression and psychotic symptoms were significantly and positively correlated with behavioral disturbances. Psychotic symptoms were associated with aggressive behavioral symptoms, and depressive symptoms were associated with constant requests for help, complaining, and negativism. Dementia severity accounted for significant variance in CMAI scores and was positively associated with behavioral disturbance; though disorder symptoms accounted for more behavioral disturbance variance than did depressive symptoms. CONCLUSIONS: Both depressive and psychotic symptoms were associated with overall behavioral disturbances in patients with dementia. Psychotic symptoms and depressive symptoms were associated with different types of behavioral disturbances. Our findings support the contention that underlying depression or psychosis may partially account for different behavioral disturbances and that not all behavioral disturbances should be globally labeled "agitation." Future studies should address symptom-specific treatment of behaviorally disturbed patients.

Aged↗
PubMed1999

The effects of free fatty acids on gluconeogenesis and glycogenolysis in normal subjects.

We have quantitatively determined gluconeogenesis (GNG) from all precursors, using a novel method employing 2H20 to address the question of whether changes in plasma free fatty acids (FFA) affect GNG in healthy, nonobese subjects. In the first study (n = 6), plasma FFA were lowered at 16 to 20 hours with nicotinic acid (NA) and were then allowed to rise at 20 to 24 hours (FFA rebound after administration of NA). FFA decreased from 387 microM at 16 hours to 43 microM at 20 hours, and then rebounded to 1,823 microM at 24 hours. GNG decreased from 58.1% at 16 hours to 38.6% of endogenous glucose production at 20 hours (P < 0.005) and then rebounded to 78. 9% at 24 hours (P < 0.05). Conversely, glycogenolysis (GL) increased from 41.9% at 16 hours to 61.4% at 20 hours (P < 0.05), and then decreased to 21.1% at 24 hours (P < 0.05). In the second study (controls; n = 6), volunteers were analyzed between 16 and 24 hours after the last meal. FFA rose from 423 to 681 microM (P < 0.05), and GNG from 50.3% to 61.7% (P < 0.02), whereas GL decreased from 49.7% to 38.3% (P < 0.05). Endogenous glucose production decreased at the same rate in both studies, from 10.7 to 8.6 micromol/kg/min (P < 0. 05). In study 3 (n = 6), in which the NA-mediated decrease of plasma FFA was prevented by infusion of lipid and heparin, neither FFA nor GNG changed significantly. In summary, our data suggest that (a) acute changes in plasma FFA produce acute changes in GNG and reciprocal changes in GL; (b) the decrease in EGP between 16 and 24 hours of fasting is due to a fall in GL; and (c) NA has no direct effect on GNG.

Adult↗
PubMed1998

Synthesis, rotamer orientation, and calcium channel modulation activities of alkyl and 2-phenethyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(3- or 6-substituted-2-pyridyl)-5-pyridinecarboxylates.

A group of racemic alkyl and 2-phenethyl 1,4-dihydro-2,6-dimethyl-3-nitro-4-(3- or 6-substituted-2-pyridyl)-5-pyridinecarboxylates (13a-q) was prepared using a modified Hantzsch reaction that involved the condensation of a 3- or 6-substituted-2-pyridinecarboxaldehyde (7a-j) with an alkyl or 2-phenethyl 3-aminocrotonate (11a-d) and nitroacetone (12). Nuclear Overhauser (NOE) studies indicated there is a significant rotamer fraction in solution where the pyridyl nitrogen is oriented above the 1,4-dihydropyridine ring, irrespective of whether a substituent is located at the 3- or 6-position. A potential H-bonding interaction between the pyridyl nitrogen free electron pair and the suitably positioned 1,4-dihydropyridine NH moiety may stablize this rotamer orientation. In vitro calcium channel antagonist and agonist activities were determined using guinea pig ileum longitudinal smooth muscle (GPILSM) and guinea pig left atrium (GPLA) assays, respectively. Compounds having an i-Pr ester substituent acted as dual cardioselective calcium channel agonists (GPLA)/smooth muscle-selective calcium channel antagonists (GPILSM), except for the C-4 3-nitro-2-pyridyl compound which exhibited an antagonist effect on both GPLA and GPILSM. In contrast, the compounds with a phenethyl ester group, which exhibited antagonist activity (IC50 = 10(-5)-10(-7) M range) on GPILSM, were devoid of cardiac agonist activity on GPLA. Structure-activity relationships showing the effect of a substituent (Me, CF3, Cl, NO2, Ph) at the 3- or 6-position of a C-4 2-pyridyl moiety and a variety of ester substituents (Me, Et, i-Pr, PhCH2CH2-) upon calcium channel modulation are described. Compounds possessing a 3- or 6-substituted-2-pyridyl moiety, in conjuction with an i-Pr ester substituent, are novel 1,4-dihydropyridine calcium channel modulators that offer a new drug design approach directed to the treatment of congestive heart failure and may also be useful as probes to study the structure-function relationships of calcium channels.

Animals↗
PubMed1998

Acute lowering of plasma fatty acids lowers basal insulin secretion in diabetic and nondiabetic subjects.

The objective of this study was to determine whether basal plasma free fatty acid (FFA) concentrations affect basal insulin secretion rates (ISRs). Effects of FFA levels on basal ISRs were evaluated by lowering basal plasma FFA levels with nicotinic acid (NA) (100-150 mg p.o., q 30 min x 4 h) in type 2 diabetic patients and in normal volunteers. Lowering of FFAs (from approximately 600 to approximately 100 micromol/l) lowered ISRs in type 2 diabetic patients during isoglycemic clamping (from 139 to 101 pmol/min; -23%; P < 0.02) and euglycemic clamping (from 99 to 63 pmol/min; -36%; P < 0.03) and in normal subjects during euglycemic clamping (from 127 to 96 pmol/min; -25%; P < 0.03). In addition, peripheral insulin concentrations decreased by approximately 30% in diabetic and nondiabetic subjects. NA had no direct effect on ISRs; that is, NA did not change ISRs when plasma FFAs were prevented from decreasing with a lipid/heparin infusion. We concluded that 1) basal plasma FFAs exerted physiologically important, long-lasting effects supporting 25-33% of basal insulin secretion in nondiabetic and diabetic subjects; 2) basal plasma FFAs were responsible for some of the hyperinsulinemia in normoglycemic obese subjects; and 3) NA had no direct effect on insulin secretion.

3-Hydroxybutyric Acid↗