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Biomedical subjects

S Karim

Publications and source records attributed to S Karim.

At least 19 recordsLinked to original sources
PubMed2005

Older people with chronic schizophrenia.

Older people with chronic schizophrenia are a numerically small but important group with complex clinical and service needs. Along with a reduction in positive schizophrenic symptoms with increasing age, a majority suffer from negative symptoms, cognitive deficits, depression, side effects due to long-term use of antipsychotics and co-morbid medical problems. They may have social disabilities making them vulnerable to poverty, isolation and poor quality of life. Evidence suggests that judicious use of antipsychotics combined with psychotherapy and psychosocial interventions are effective. There are shortcomings in the standard of both hospital and community care, and the cost implications of providing adequate services are high.

Aged↗
PubMed2003

Comparison of CT and MRI in the pre-operative staging of rectal adenocarcinoma and prediction of circumferential resection margin involvement by MRI.

OBJECTIVE: It has been suggested that MRI may be used as the sole modality of choice in pre-operative staging in rectal cancers. Knowledge of tumour stage and a threatened Circumferential Resection Margin (CRM) pre-operatively are essential for planning neo-adjuvant therapy and as predictors of local recurrence. At present most units utilize CT scanning to assess these parameters. The aim of our study was two fold: firstly to examine the accuracy of preop CT and MRI staging of rectal cancers compared with final histology and secondly to assess the accuracy of MRI in predicting penetration of the mesorectal envelope (ME). PATIENTS AND METHODS: All patients with biopsy proven rectal adenocarcinoma underwent thin slice MRI and CT scan pre-operatively. Forty-seven patients have been prospectively entered into the study: 24 male (median age 68 years; range 38-91 years). Eleven patients were unsuitable for surgery leaving 36 patients available for study. RESULTS: CT correctly staged patients with T1/T2 rectal cancers more often than MRI (77% vs. 43%, P = 0.226). Patients with T1/T2 tumours were overstaged more often by MRI compared with CT (54% vs. 23%, P = 0.226). A greater proportion of patients with T3 tumours were correctly staged by MRI than CT (76% vs. 41%, P = 0.08); and more T3 disease was understaged by CT than MRI (54 vs. 18%, P = 0.032). CT and MRI staged T4 disease equally. In the assessment of mesorectal envelope integrity, MRI had a sensitivity of 80% and a specificity of 84%. The positive predictive value was 44% and the negative predictive value 96%. CONCLUSIONS: These results suggest significant differences between accurate pre-operative "T" staging by CT and MRI for rectal cancer. MRI has the potential however, to accurately assess mesorectal envelope invasion. Further analysis is required to assess whether MRI can be used as the sole modality in pre-operative staging of rectal cancers.

Adenocarcinoma↗
PubMed2002

Identification of SNARE and cell trafficking regulatory proteins in the salivary glands of the lone star tick, Amblyomma americanum (L.).

Prostaglandin E(2) (PGE(2)) stimulates secretion of tick salivary gland proteins via a phosphoinositide signaling pathway and mobilization of intracellular Ca(2+) (). Highly conserved intracellular SNARE (soluble NSF attachment protein receptors) complex proteins are associated with the mechanism of protein secretion in vertebrate and invertebrate neuronal and non-neuronal cells. Proteins in the salivary glands of partially fed female lone star ticks cross-react individually with antibodies to synaptobrevin-2 (vesicle (v)-SNARE), syntaxin-1A, syntaxin-2 and SNAP-25 (target (t)-SNAREs), cytosolic alpha/beta SNAP and NSF (N-ethylmaleimide-sensitive fusion protein), Ca(2+) sensitive synaptotagmin, vesicle associated synaptophysin, and regulatory cell trafficking GTPases Rab3A and nSec1. V-SNARE and t-SNARE proteins form an SDS-resistant, boiling sensitive core complex in the salivary glands. Antibodies to SNARE complex proteins inhibit PGE(2)-stimulated secretion of anticoagulant protein in permeabilized tick salivary glands. We conclude that SNARE and cell trafficking regulatory proteins are present and functioning in the process of PGE(2)-stimulated Ca(2+) regulated protein secretion in tick salivary glands.

Animals↗
PubMed2001

Hybrid capture as a means of detecting human papillomavirus DNA from liquid-based cytology specimens: a preliminary evaluation.

The connection between human papillomavirus (HPV) and cervical cancer is well documented, as is the benefit of an adjunctive, standardised objective test to complement cervical screening. Here, 197 liquid-based cytology (LBC) specimens previously processed for cytological examination (75 negative, 108 borderline/mild dyskaryosis, and 14 moderate/severe dyskaryosis) are examined for the presence of HPV using a hybrid capture assay. Of the 197 specimens tested for HPV DNA, 97 (49.2%) were positive using the combined high/low-risk probe, and 59 (29.9%) were negative cytologically and with the hybrid capture HPV test; however, 16/175 (21.3%) specimens classified as negative cytologically with LBC proved positive for HPV by hybrid capture. Of the 122 samples that showed abnormal cytology, 81 (66.4%) were positive for HPV. Although the number of samples tested is small, the results show that the use of LBC technology for both cervical cytological screening and the hybrid capture test has the potential to reduce both false-negative and -positive rates associated with cytological screening alone.

Adolescent↗
PubMed2000

Bacillus thuringiensis delta-endotoxin proteins show a correlation in toxicity and short circuit current inhibition against Helicoverpa zea.

Pesticidal activity of Bacillus thuringiensis delta-endotoxins, Cry1Aa, Cry1Ab, Cry1Ac, and Cry2A, was determined by using the force-feeding bioassay method to 4(th) instar larvae of Helicoverpa zea. H. zea was susceptible to Bt toxins in the order Cry1Ac > Cry1Ab > Cry1Aa > Cry2A with 63.60, 89.04, 159.65, and 375.78 ng/larvae respectively. The abilities of selected Bacillus thuringiensis toxins to inhibit short circuit current (I(SC)) in midgut epithelia of H. zea were also investigated by voltage clamp assay. The voltage-clamp studies were conducted on isolated midguts, measuring the inhibition of short circuit current (I(SC)) by activated toxin. A Cry1Aa toxin dilution of 33.3 and 500 ng/ml resulted in inhibition of I(SC) of -2.29 microA/min (lag time 15 min) and -4.48 microA/min (lag time, 2 min) respectively. The Cry1Ab dilution of 25 ng/ml inhibited I(SC) to -1.39 microA/min, a lag time of 14 min, and 333.3 ng/ml dilution resulted in decay of I(SC) -2.49 microA/min, lag time 1 min respectively. The Cry1Ac lower dilution 16.7 ng/ml inhibited I(SC) to -1.39 microA/min, lag time 4 min, and a high dilution 333.3 ng/ml decay I(SC) to -2.44 microA/min, lag time 1 min. The inhibition of I(SC) (-1.10 microA/min, lag time 25) at lower dilution (33.3 ng/ml) and high dilution (500 ng/ml), decay (-2.38 microA/min, lag time 5 min), showed a correlation between toxin concentration and inhibitory response with Cry2A toxin. The lag time decreased with increasing concentration of toxin applied, which is additional evidence of dose response besides direct correlation of toxicity assays and I(SC).

Animals↗
PubMed2000

Toxicity and receptor binding properties of Bacillus thuringiensis delta-endotoxins to the midgut brush border membrane vesicles of the rice leaf folders, Cnaphalocrocis medinalis and Marasmia patnalis.

Pesticidal activity and receptor-binding properties of Bacillus thuringiensis toxins to rice leaf folders, Cnaphalocrocis medinalis and Marasmia patnalis, were investigated. Saturation and competition binding experiments were done with iodine ((125)1)-labeled Bt proteins and brush border membrane vesicles prepared from the midgut of C. medinalis and M. patnalis. The results show saturable, specific, and high-affinity binding of all toxins except Cry2A toxin. Cry1Aa and Cry2A toxins were bound with low affinity but with high binding site concentration. Heterologous competition experiments showed that Cry1Aa, Cry1Ab, and Cry1Ac recognized or shared the same binding site that is different from the binding site for Cry2A toxin. Iodine ((125)I)-labeled Cry1Ac and Cry1Ab toxins were used in ligand blot experiments to detect specific binding proteins in brush border membrane vesicles of C. medinalis and M. patnalis. Cry1Ab toxin protein binds to 205-kDa and 200-kDa proteins respectively in case of C. medinalis and M. patnalis. The apparent molecular mass of the protein bound to labeled Cry1Ac toxins was identified as a 120-kDa protein in both C. medinalis and M. patnalis.

Animals↗
PubMed2000

Pesticidal and receptor binding properties of Bacillus thuringiensis Cry1Ab and Cry1Ac delta-endotoxin mutants to Pectinophora gossypiella and Helicoverpa zea.

Bacillus thuringiensis produces several larvicidal crystalline inclusions during sporulation. An understanding of their mechanisms of action is commercially important. In this study, two toxins, Cry1Ab and Cry1Ac, were compared that showed 98% amino acid identity in domain I and II, but differed significantly in domain III. Using site-directed mutagenesis techniques, two conserved loop 2 Arg's ((368)RR(369)) of Cry1Ab and Cry1Ac toxins were replaced with Ala ((368)AR(369), (368)RA(369), (368)AA(369)), Glu ((368)EE(369)), Phe ((368)FF(369)), His ((368)HH(369)), and Lys ((368)KK(369)). The effect of these mutants on structural stability, larvicidal potency, receptor binding, and ionic permeability towards two important cotton pests, pink bollworm (Pectinophora gossypiella) and bollworm (Helicoverpa zea) were analyzed. All seven mutants of Cry1Ab, excluding (368)AR(369), produced a stable protoxin, whereas for Cry1Ac all seven mutants yielded stable protoxin. Results showed that all the stable mutants behaved similarly to the wild type on incubation with trypsin and gut extract of both insect larvae. The Cry1Ab mutants, (368)AR(369), (368)AA(369), (368)FF(369), and (368)HH(369), lost toxicity; (368)EE(369) had reduced toxicity; whereas the more conserved change (368)KK(369) retained the toxicity similar to the wild type towards P. gossypiella. Double mutants of Cry1Ac, (368)AA(369) and (368)FF(369), abolished the toxicity. Double mutant (368)KK(369) of Cry1Ac retained its toxicity against P. gossypiella, whereas single mutants (368)AR(369), (368)RA(369), and (368)HH(369) retained only reduced toxicity. All the mutants of Cry1Ab lost their toxicity against H. zea except (368)KK(369). In Cry1Ac single mutants, (368)AR(369) and (368)RA(369), reduction in the toxicity was observed. A double mutant of Cry1Ac, (368)KK(369), also retained reduced toxicity. All the other double mutants lost their toxicity. Voltage clamping experiments on H. zea midguts provided an additional evidence about the insecticidal property and inhibition of I(sc) across the transepithelial membrane of the insect midgut.

Animals↗
PubMed1997

Regulatory role of prostaglandin E2 in induction of cyclo-oxygenase-2 by a thromboxane A2 analogue (U46619) and basic fibroblast growth factor in porcine aortic smooth-muscle cells.

U46619, a thromboxane A2 analogue, and basic fibroblast growth factor (FGF-2) both induced the expression of the inducible cyclo-oxygenase (Cox)-2 in porcine aortic smooth-muscle cells. This induction was dose-dependent (submaximal at 300 nM for U46619 and 1 ng/ml for FGF-2) and time-dependent, with similar intensity and maximal expression at 2 h. Under these conditions, both inducers stimulated rapid activation of extracellular signal-regulated kinase (ERK2) at 5-10 min, a transient and lower intensity being induced by U46619 whereas that induced by FGF-2 was sustained (>1 h). PD98059, an inhibitor of the ERK pathway, inhibited the expression of Cox-2. In contrast, activation of Jun-N-terminal kinase (JNK1) was sustained with U46619 but poorly induced by FGF-2. Cox-2 expression induced by U46619 or FGF-2 was similarly reduced by prostaglandin (PGE2), forskolin or dibutyryl-cAMP, suggesting a regulatory effect of adenylate cyclase on Cox-2 expression. However, activation of ERK2 by FGF-2 was not affected by PGE2 whereas that of JNK1 by U46619 was inhibited, suggesting that inhibition of COX-2 expression by cAMP may be downstream of ERK2. The effects of PGE2 and forskolin on Cox-2 and phosphorylation of JNK1 were reversed with the protein kinase A inhibitor H89. In addition, endogenous PGE2 down-regulated the expression of Cox-2 by the two inducers, as stimulation of the cells in the presence of different Cox inhibitors increased the expression of the protein. Overall, these results suggest that exogenous and endogenous PGE2 exert negative inhibitory effects on Cox-2 expression mediated by stimulation of protein kinase A.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1996

Cyclooxygenase-1 and -2 of endothelial cells utilize exogenous or endogenous arachidonic acid for transcellular production of thromboxane.

The presence of prostaglandin (PG) H2 in the supernatant of human umbilical vein endothelial cells (HUVEC) stimulated by thrombin restores the capacity of aspirin-treated platelets to generate thromboxane (TX) B2. Induction of cyclooxygenase-2 (Cox-2) by interleukin (IL)-1alpha or a phorbol ester increases this formation. HUVEC treated with aspirin lost their capacity to generate PGs but recovery occurred after 3- or 6-h induction of Cox-2 with phorbol ester or IL-1alpha. Enzyme activity of the newly synthesized Cox-2 in aspirin-treated cells, evaluated after immunoprecipitation, was similar to untreated cells but after 18 h of cell stimulation only 50-60% recovery of Cox-1 was observed. The use of SC58125, a selective Cox-2 inhibitor, confirmed these findings in intact cells. Cyclooxygenase activity was related to the amount of Cox proteins present in the cells, but after induction of Cox-2, contribution of the latter to PG production was 6-8-fold that of Cox-1. Aspirin-treated or untreated cells were incubated in the absence or presence of SC58125 and stimulated by thrombin, the ionophore A23187, or exogenous arachidonic acid. The production of endogenous (6-keto-PGF1alpha, PGE2, PGF2alpha) versus transcellular (TXB2) metabolites was independent of the inducer, the source of arachidonic acid and the Cox isozyme. However, in acetylsalicylic acid-treated cells, after 6-h stimulation with IL-1alpha, newly synthesized Cox-2 produced less TXB2 than 6-keto-PGF1alpha compared to untreated cells. At later times (>18 h), there was no metabolic difference between the cells. These studies suggest that in HUVEC, Cox compartmentalization occurring after short-term activation may selectively affect transcellular metabolism, but not constitutive production, of PGs.

Arachidonic Acid↗
PubMed1994

Isolation, identification and sensitivity pattern of microorganisms isolated from the urine of pregnant women.

The present studies were conducted to detect and identify the microorganism from the urine of pregnant women having urinary tract infection. The antibiotic susceptibility of these isolated microorganisms was also determined. The microorganisms found responsible for the infection were bacteria, fungi, yeast and protozoa. Among the bacteria two were identified as Gram-positive cocci i.e. Staphylococcus aureus and S. epidermidis, the remaining two were Gram-negative bacilli which were Escherichia coil and Pseudomonas aeruginosa. The fungus was identified as AspelEillus niger and the yeast like fungus Candida albican. The only protozoan found in some of the urine samples was Trichomonas vaginalis. These isolated and identified microorganisms were more susceptible to Norfloxacin, Velosef, Minocin, Nitrofurantoin, Malidixic acid and Metronidazole whereas antibiotics Penbritin and Cefaloridine were least effective against these microorganisms.

Journal Article↗
PubMed1990

Isradipine in Asian patients with hypertension.

Isradipine, a new calcium antagonist, was administered to 51 Pakistani patients with hypertension (36 women, 15 men; mean age 47 years) over an 8-week period. Mean sitting systolic, and sitting and standing diastolic blood pressure was significantly reduced, and mean standing systolic blood pressure tended to decrease. Laboratory values, and both sitting and standing heart rates were not significantly affected by isradipine treatment. At the end of 8 weeks, 41.2% of patients were receiving isradipine 1.25mg twice daily, and 58.8% were receiving 2.5mg twice daily. Isradipine was found to be effective and well tolerated in Pakistani patients with mild to moderate hypertension.

Adult↗
PubMed1989

[The effect of nifedipine and fentanyl on changes in the circulatory reaction to endotracheal intubation].

UNLABELLED: Recommendations for prevention of hypertension and tachycardia during the induction of anesthesia include the use of fentanyl and antihypertensive drugs and superficial anesthesia of the throat. Nifedipine has been used to treat acute hypertension and in many cases it has proved superior to other antihypertensive drugs. The present study was designed to find whether prophylactic injection of nifedipine alone or in combination with fentanyl can prevent cardiovascular responses during endotracheal intubation. METHODS: A total of 140 female patients (ASA groups I or II) with no history of arterial hypertension were randomly allocated to 7 groups: group K was the control group, in which patients received only saline solution; patients in groups 0,1F; 0,2F; 0,3F received 0.1, 0.2 or 0.3 mg fentanyl, respectively; those in group 1,0N, 1 mg nifedipine; those in group 0,5N + 0,1F, 0.5 mg nifedipine, plus 0.1 mg fentanyl; and those in group 1,0N + 0,1F 1 mg nifedipine plus 0.1 mg fentanyl. Blood pressure and heart rate were measured at 1 min intervals. After estimation of control values the prophylactic drug or combination of drugs was injected. Anesthesia was induced in the conventional manner. Plasma concentrations of epinephrine and norepinephrine were analyzed before intubation and at 5, 30 and 60 min intervals after intubation. Side-effects, especially respiratory depression and arrhythmia, were carefully recorded. RESULTS: In group K only systolic BP increased significantly after intubation. In the other groups the peak systolic blood pressure was not statistically different from the preinjection values. Diastolic BP increased significantly after intubation in all but two groups: in group 0,3F and in group 1,0N + 0,1F there was no significant difference in diastolic BP compared with the control values. The heart rate increased significantly in the control group after intubation as well as in groups 0,1F and 0,2F. In patients receiving 0.3 mg fentanyl there was no change in HR after intubation. Administration of 1 mg nifedipine alone (group 1,0N) or in combination with 0.1 mg fentanyl (group 1,0N + 0,1F) caused tachycardia even before intubation, whereas the combination of 0.5 mg nifedipine and 0.1 mg fentanyl did not result in a significant increase of HR following intubation. In all groups, epinephrine concentrations were significantly lower 5 min after intubation. A return to the control values was observed after 60 min in all groups except group 0,1F. Serum concentrations of norepinephrine were lower 5 min after intubation in all groups and were still low in groups 0,1F , 0,2F, 0,5N+0,1F and 1,0N+0,1F up to 60 min after intubation. Side-effects and adverse effects were checked for in the present study. An increase in heart rate was observed during induction in almost every group. More pronounced changes were recorded in groups 1,0N and 1,0N+ 0,1F receiving 1 mg nifedipine.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Clinicopathological profile of bronchogenic carcinoma in Bangladesh.

This study reflects some of the basic facts and present status of bronchogenic carcinoma in Bangladesh. Of the total patients admitted in one surgical unit of IDCH during the period 1983 to 1986, 28.7 were clinically suspected to be suffering from bronchogenic carcinoma. Males largely dominated the females (82.4 percent as against 17.6 percent) giving a ratio of 4.6:1.0, and more than 90 percent of the victims were heavy smokers. All the suspected patients were then subjected to radiological examination of chest, bronchoscopic examination (73.0 percent), histopathological examination of the bronchial biopsy specimen and sputum cytological examination (63.2 percent) cases. Bronchoscopic examination revealed endobronchial tumor or suspicious lesion in 63.2 percent cases. The sputum cytological examination were positive for malignant cells in 35.6 percent cases. Histopathological gradation of the carcinoma in order of frequencies were squamous cell carcinoma (13.3 percent), large cell carcinoma (9.7 percent) and adenocarcinoma (4.2 percent) respectively. About one fourth of the cases (27.6 percent) were found to be clinically suitable for operation but on thoracotomy resectability was possible only in 20.6 percent cases. Inoperable cases were subsequently referred for radio or chemotherapy. Follow-up of the cases were rather difficult.

Adult↗