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Biomedical subjects

S Rizvi

Publications and source records attributed to S Rizvi.

At least 19 recordsLinked to original sources
PubMed2006

Is post-Lipiodol CT better than i.v. contrast CT scan for early detection of HCC? A single liver transplant center experience.

Hepatocellular carcinoma is a highly vascular neoplasm usually arising from a cirrhotic liver. Delayed, noncontrast, computed tomography (CT) imaging after 7 to 14 days reveals an oil-based contrast agent to be concentrated in the tumor but not in normal hepatic parenchyma. The aim of this study was to retrospectively correlate the post Lipiodol CT scan findings with respect to tumor size in the explanted liver. We retrospectively reviewed adult patients who had undergone orthotopic liver transplantation between November 1995 and December 2004 and also had an hepatic arteriogram with Lipiodol injection as part of their pretransplant workup. We calculated sensitivity, specificity, false-negativity, false-positivity, and accuracy of the test, as well as positive and negative predictive values. Lipiodol CT exam had sensitivity of 1.0; specificity of 0.6 with a calculated positive predictive value of 0.89 and a negative predictive value of 1.0. Overall accuracy of Lipiodol CT scan test was found to be 0.91, which was superior to an intravenous contrast CT alone. In conclusion, because of the higher sensitivity and accuracy values, hepatic arterial Lipiodol injection can be considered during the pretransplantation workup of high-risk cirrhotic patients, since the current model for End-stage Liver Disease scoring system for hepatocellular carcinoma is built on the ultimate bulk of the tumor. Further multicenter, controlled, large-volume prospective studies are warranted to verify this observation.

Adult↗
PubMed2005

Liver transplantation for hepatitis B in the United States.

AIM: To evaluate the impact of hepatitis B virus (HBV) on US health care system, we reviewed the Organ Procurement and Transplantation (OPTN, formerly UNOS) HBV database. METHOD: We reviewed records of liver transplantations (LTx) performed in the United States listed for the diagnoses of HBV between 1993 and mid-October 2004. Both acute as well as chronic cases were included. Coinfection with hepatitis C virus was excluded from study. The specific states selected for review were chosen from those areas that are receiving large numbers of new immigrants from high HBV endemic areas (ie, Texas, Pennsylvania, California, New York, and Florida). One-, 3-, and 5-year patient survival rates for both cadaveric and living related donors were analyzed. Survival rates were obtained from OPTN database as Kaplan-Meyer survival test. RESULTS: Between 1993 and mid-October 2004, 53,312 LTx had been performed nationwide. Of these, 2314 (4.34%) were performed for the diagnosis of HBV; 1816 cases (78%) were due to chronic HBV infection (45 of them were living donor LTx) and 498 cases (22%) were due to HBV-induced acute liver failure (seven of them were living donor LTx). Three- and 5-year survival rates of chronic HBV-related LTx patients were better than acute HBV-related and overall LTx patients. CONCLUSION: HBV is generally considered to have a minor health significance by many community gastroenterologists. With growing immigration from overseas, it may eventually have a higher impact on LTx. Therefore, it is crucial to further educate gastroenterologists and primary care physicians caring for this specific group of patients.

Geography↗
PubMed2005

Variation in end-of-life decision making between critical care consultants.

Considerable variation in end-of-life decision making is reported between intensive care units in the United Kingdom, possibly because of differences in casemix. Senior medical staff within any one unit should, however, be consistent in such decision making. We reviewed the medical records for a 4-year period to establish if there was consistency in our own unit. This revealed considerable variation in the apparent willingness of consultants to make end-of-life decisions, emphasising the subjective nature of these decisions. Personality typing (Myers-Briggs Type Indicator) of consultants revealed that those who had made more than the expected number of decisions had scores towards the judging end of the judging/perceiving domain.

Attitude of Health Personnel↗
PubMed2002

Risk factors for lamb mortality on UK sheep farms.

Data on neonatal-lamb mortality and flock history were recorded by veterinary students working on 108 sheep farms in the UK in Spring 1997. The mean reported mortality incidence risk was 10.0% (median 9%; inter-quartile range 5.9-12.3%). The outcomes were incidence risks of stillbirth, perinatal (within 24h of birth) mortality and postnatal (>24h after birth) mortality. Exposures were screened for univariable associations with mortality risk. Logistic binomial multiple regressions adjusted for confounding, with farm as a random effect. This study has raised hypotheses for management factors associated with lamb mortality that warrant further study. Intensive rearing systems appear to be associated with increased perinatal and postnatal mortality, although housing ewes at lambing was associated with a decreased risk of stillbirth. High perinatal mortality also was associated with poor mothering-pen hygiene, flocks that foster more lambs, and failure to provide appropriate nursing for sick lambs. Larger flocks, poor ewe condition at breeding, and flocks with higher ewe-replacement rates were associated with higher postnatal mortality.

Animal Husbandry↗
PubMed2002

In vitro cytotoxicity of bismuth-213 (213Bi)-labeled-plasminogen activator inhibitor type 2 (alpha-PAI-2) on human breast cancer cells.

Metastasis is the principal cause of death in breast cancer patients. New and improved treatments for eradicating micrometastases are needed. To this end, a novel alpha-emitting protein construct, 213Bi-labelled plasminogen activator inhibitor type-2 (PAI-2) (alpha-PAI-2), was evaluated in vitro. This construct exploits: (a) the overexpression of the cell-surface receptor bound urokinase plasminogen activator (uPA) in the metastatic spread of breast cancer cells; (b) the binding and inhibition of receptor-bound uPA by PAI-2; and (c) the high cytotoxicity of alpha radiation. High labeling efficiencies and stability of 213Bi bound to human recombinant PAI-2 conjugated with cyclic diethylenetriaminepentaacetic acid anhydride were achieved (greater than 90%). The uPA inhibitory activity of the chelated PAI-2 was maintained as determined by complex formation with uPA and by inhibition of uPA activity. Furthermore, the reactivity of alpha-PAI-2 was confirmed in a cell assay as this construct was highly cytotoxic to breast cancer cell lines that express active, receptor bound uPA. The specificity of alpha-PAI-2 targeting was shown using several controls. Firstly, an active uPA blocking agent that limits PAI-2 binding significantly improved cell survival by a factor greater than three. Secondly, a non-specific alpha-BSA construct had minimal cytotoxic effect. Moreover, alpha-PAI-2 was not cytotoxic to freshly isolated normal human leukocytes, confirming that cells which do not contain active, receptor bound uPA cannot be targeted by alpha-PAI-2. In conclusion, we have validated, in vitro, the potential of alpha-PAI-2 as a novel therapeutic agent for breast cancer.

Bismuth↗
PubMed2001

In vivo studies of Gd-DTPA-monoclonal antibody and gd-porphyrins: potential magnetic resonance imaging contrast agents for melanoma.

New tumor-specific contrast agents for clinical imaging and therapy for cancer are required. To this end Gd-H (Gd-hematoporphyrin), Gd-TCP (Gd-tetra-carboranylmethoxyphenyl-porphyrin), Gd-DTPA-WM53, and Gd-DTPA-9.2.27 were synthesized and administered by systemic injection to nude mice with human melanoma (MM-138) xenografts. The biodistribution T1 relaxation times and magnetic resonance (MR) image signal enhancement of the contrast agents are presented for the first time and compared for each group of five mice. A change (20%) in T1 relaxation times of water in human melanoma tumor xenografts was revealed 24 hours after injection of the labeled immunoconjugate Gd-DTPA-9.2.27. The percent of injected antibody or gadolinium that localized to the tumor was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) to be approximately 35%. A higher concentration of gadolinium was achieved compared with nonspecific compounds, indicating selective delivery of Gd-DTPA-9.2.27 to the melanoma xenografts. Porphyrin-based contrast agents (Gd-H and Gd-TCP) also showed significant uptake in melanomas. The uptake of Gd-TCP by the tumor was sufficient to deliver boron atoms into the tumor, making possible dual use for both MR imaging (MRI) and boron neutron capture therapy (BNCT). The linear relationship found between the paramagnetic contribution to the relaxation rates and contrast agent concentration allows quantitative studies of paramagnetic contrast agent uptake.

Animals↗
PubMed1998

Risk factors for vulva biting in breeding sows in south-west England.

A postal survey was conducted on 410 pig farms in south-west England to investigate the risk factors for vulva biting. The results of the bivariate analyses indicated that group housing, keeping a boar in the same pen and the number of sows per drinker were significantly associated (P < or = 0.05) with vulva biting in service sows. Group housing, group size, keeping a boar in the same pen, straw bedding, electronic sow feeders, feeding once daily, providing water automatically and the number of sows per drinker were significantly associated with vulva biting in dry sows. Vulva biting was also significantly associated with an increased percentage of culled sows and the occurrence of tail biting on the farm. A logistic regression analysis showed that group size and the number of sows per drinker were significant risk factors for vulva biting in service sows, and once a day feeding, group size, the number of sows per drinker and providing water automatically were significant risk factors for dry sows.

Animal Husbandry↗
PubMed1998

Fetal loss after early detection of heart motion in infertility patients. Prognostic factors.

OBJECTIVE: To evaluate the incidence and prognosticators of spontaneous abortion (< 20 weeks' gestation) in an infertile population after early documentation of fetal cardiac activity. STUDY DESIGN: Retrospective chart review. We examined the incidence of spontaneous abortion in 231 clinical pregnancies with 259 fetuses documented to be viable by transvaginal sonography 28-38 days after ovulation. The population was an unselected group of infertility patients with no history of recurrent pregnancy loss. Maternal age and presence of multiple gestations were analyzed as separate variables by chi 2 testing. RESULTS: The incidence of spontaneous abortion among all fetuses was 9.6% (95% confidence interval [CI], 6.1-13.2%) and among singleton gestations was 7.7% (95% CI, 4.0-11.3%). Women with multiple gestations were more likely to suffer spontaneous fetal loss as compared to women with singleton gestations (18 vs. 7.6%, P < .05). In addition, women aged 35 and above with singleton pregnancies showed a significantly increased rate of fetal loss (13.4 vs. 4.9%, P < .05) when compared with younger women. CONCLUSION: Women > or = 35 years old and those with multiple gestations were significantly more likely to suffer late first- or early second-trimester fetal loss even after detection of fetal cardiac activity. These patients should be counseled differently than younger women with singleton pregnancies, and increased monitoring may be indicated.

Abortion, Spontaneous↗
PubMed1997

Fibrinolysis, inhibitors of blood coagulation, and monocyte derived coagulant activity in acute malaria.

Different parameters of fibrinolytic systems like t-PA, PAI, D-dimer, and inhibitors of blood coagulation, i.e., protein C (PC), protein S(PS), and antithrombin III (AT-III), have been studied in cases of acute malaria due to Plasmodium falciparum and plasmodium vivax infection, and these patients were followed up. It was observed that the plasma PAI-1 was very high in cases of P. falciparum malaria infection as compared to normal controls and P. vivax infection. The changes in complicated cases of P. falciparum were remarkable as compared to uncomplicated ones. The PC, PS, and AT-III levels were also low in P. falciparum, particularly so in complicated cases, and were normal in P. vivax infection. The factor VIII R:Ag levels were invariably high in acute malaria. On follow-up of some of these cases the values came back to normal after the antiparasite treatment. The monocyte procoagulant activity was found to be significantly higher in P. falciparum infection as compared to that of P. vivax infection. All these findings therefore contribute towards the production of a hypercoagulable state in P. falciparum infection and partly explain the complications of P. falciparum infection like cerebral malaria.

Antithrombin III↗
PubMed1996

Synthesis, physicochemical properties, and biological evaluation of hydroxypyranones and hydroxypyridinones: novel bidentate ligands for cell-labeling.

The synthesis of a range of hydroxypyranones and hydroxypyridinones with potential for the chelation of indium(III) is described. The crystal structures of two of the indium complexes are presented. The distribution coefficients of the ligands and the corresponding iron(III), gallium(III), and indium(III) complexes are reported. Good linear relationships between the distribution coefficients of the iron and gallium complexes and iron and indium complexes were obtained. In contrast a nonlinear relationship was obtained between the distribution coefficient of the free ligand and the distribution coefficient of the three groups of complexes. This latter relationship was used to identify compounds with optimal cell labeling properties. Two such compounds both 6-(alkoxymethyl)-3-hydroxy-4H-pyran-4-ones have been compared with tropolone for their ability to label human leucocytes with 111In. The leucocyte labeling efficiencies of the selected ligands were greater and the in-vitro plasma stabilities were similar to that of 111In-tropolonate. These results suggest that the new bidentate ligands may offer advantages over those currently used for cell-labeling.

Cells↗
PubMed1996

Coagulation abnormalities in patients with Gaucher's disease: effect of therapy.

Various coagulation defects have been associated with Gaucher's disease, including factor IX deficiency and acquired von Willebrand's disease (VWD). We performed repeated coagulation assays in 9 patients with Gaucher's disease over a period of 2 years. The prothrombin time (PT) and fibrinogen levels were normal in 8 of 9 patients, while the partial thromboplastin time (PTT) was abnormal in 5 of 9; all mixing PTT tests showed correction. Factor IX was normal repeatedly in the 7 of 7 patients tested. In contrast, factor XI was decreased in 3 of 9 patients assayed. Anticardiolipin (ACL) IgM was normal in all patients. ACL IgG was highly variable; levels were abnormal at least once in 6 of 8 patients, but were also normal at least once in 7 of 8 patients. Factor VIII was also quite variable: levels were decreased at least once in 4 of 9 patients, and normal at least once in 8 of 9 patients. Von Willebrand factor antigen (VWF Ag) studies were normal in 7 of 8 patients, but VWF activity was decreased at least once in 4 of 8 patients. In some patients, these problems could be overcome by specimen dilution. In ony 1 patient was VWF Ag decreased; this patient had a factor VIIIC level of 13% , and VWF activity of 18.7%. Coagulation assays performed before and after alglucerase administration failed to demonstrate any significant improvement in these assays, and neither was there a consistent improvement over the duration of therapy. We suggest that previously reported decreases in factor IX and VWF may be secondary to the interfering presence of increased cerebroside levels. Caution must be used in the interpretation of clotting assays in the patient with Gaucher's disease.

Antibodies, Anticardiolipin↗
PubMed1993

Carcinoembryonic antigen assay of intra-abdominal fine-needle aspirates.

Differentiating abscesses from necrotic tumors has important therapeutic implications. Currently, cytologic examination is the "gold standard," but it has a low sensitivity for cystic/necrotic tumors. To address this problem, a prospective study was conducted comparing the results of cytologic examination with those of carcinoembryonic antigen (CEA) immunoassay of fine-needle aspirates in 24 patients undergoing radiologically or surgically guided fine-needle aspiration. Of 26 fine-needle aspirates, 20 were malignant and 6 benign. Final results were correlated with pathologic examination (when available), clinical review, and follow-up. Three patients had an abscess associated with perforated, recurrent carcinoma, of whom only one had cytologic assessment prior to drainage. The sensitivity of fine-needle aspiration was 85%, and for adenocarcinoma alone, 80%. CEA sensitivity (greater than 5 ng/mL) was 50%, and for adenocarcinoma, 90%; the specificity of the assay was 64%. A high CEA level alone was diagnostic of metastatic carcinoma of the colon in two fine-needle aspirates. Cytologic assessment and CEA assay of fine-needle aspirates and cyst/abscess drainage facilitate the diagnosis of unsuspected adenocarcinoma.

Abscess↗
PubMed1990

Rubella susceptibility and continuing risk of infection in pregnancy.

Sera of 2000 pregnant women attending the antenatal clinic of the Aga Khan University Hospital were tested for rubella antibodies. Of these 1684 (84.2%) were immune and 316 (15.8%) were susceptible to rubella. Majority (99.8%) of the women were Asian in origin. Susceptibility decreased with increasing age and parity. We conclude that apart from vaccination of all young children greater attention should be paid to immunization of women of child-bearing age.

Female↗
PubMed1982

Automation of the homogeneous substrate-labeled fluorescent immunoassay for theophylline in serum: application to the determination of phenytoin and phenobarbital in serum.

A substrate labeled fluorescent immunoassay procedure for serum theophylline has been automated. The method uses the Ames (SLFIA) substrate-labeled fluorescent immunoassay reagents and Technicon AutoAnalyzer equipment. Forty-seven sera analyzed for theophylline by the automated Ames SLFIA procedure and by the Syva EMIT method yielded the regression equation y (Ames) = 0.92x (Syva) + 0.47, SE, sy.x = 1.67, and correlation coefficient r = 0.934. Recoveries ranged from 94.6 to 100% by the automated SLFIA method. Within-run mean and SD for a sample in and above the therapeutic range was 14.5 +/- 0.37 and 22.7 +/- 1.0 mg/L, respectively. Day-to-day reproducibility was 13.4 +/- 0.92 and 24.7 +/- 1.71 mg/L for a sample in and above the therapeutic range, respectively. The automated SLFIA procedure analyzes serum for theophylline at the rate of 40 per hour and gives results comparable to the Syva EMIT method. The same equipment was also used for the SLFIA determination of phenytoin and phenobarbital and yielded reliable results. The manifold and equipment were the same. The only change was the substitution of the Ames phenytoin and phenobarbital reagents for the theophylline reagent.

Autoanalysis↗
PubMed1980

Cognitive sequelae in relationship to early indices of severity of brain damage after severe blunt head injury.

A group of 89 severely head injured patients was tested psychologically within two years of injury, and test performance was related to indices of brain damage. Duration of coma (Glasgow Coma Scale) bore little relationship to later cognitive outcome but duration of post-traumatic amnesia significantly predicted cognitive performance. Patients with an operated haematoma performed better than non-operated cases, reflecting a selection bias. The side of haematoma was not significant, nor were the presence, or type, or side of skull fracture.

Adolescent↗
PubMed1966

Phage resistance in Vibrio cholerae.

Mukerjee cholera phages are being extensively used in the classification of vibrios. However, the studies reported here show that phage-resistant mutants that are exactly like the parent strains in all characteristics except phage reactions can easily be obtained. For this reason phage reactions should be considered only as a marker and not as the final arbiter in vibrio classification, e.g., in attempting to identify the El Tor vibrio. Confirmatory evidence should always be sought.It is also shown that routine phage work can be simplified by preparing phage-specific hosts and using them for the preparation of phage stocks without any fear of cross-contamination. The properties of phages prepared on the specific hosts are similar to those of phages prepared on the universal host.

Bacteriophage Typing↗