Comparison of Zirconia to Dentin Bonding Using Resin-Based Luting Cements and Resin-Modified Glass-Ionomer Cement: In vitro.

Introduction: The aim of this study was to compare the shear bond strengths of zirconia to dentin using two resin-based luting cements and a resin-modified glass-ionomer cement (RMGIC). Materials and Methods: Thirty six zirconia blocks of 2 mm × 3 mm × 5 mm were milled and luted to the exposed dentin surfaces and grouped into three according to the cement used for luting: Group I - luted with Panavia F2.0, Group II - luted with RelyX U200, and Group III - luted with FujiCEM. After thermocycling, specimens were subjected to shear bond testing in an Universal Testing Machine (UTM). Data analysis using Kruskal-Wallis ANOVA and post hoc Mann-Whitney U-test with P < 0.05 was done. Results: Mean bond strengths were of the order Panavia F2.0 (5.99 MPa)>RelyX U200 (4.79MPa)>FujiCEM (1.59 MPa). Maximum failures were at the zirconia-cement interface and were adhesive in nature. Conclusions: It can be concluded with the study that there is a better bonding of zirconia to dentin with resin-based luting cements than a RMGIC. The single-step resin-luting cement RelyX U200 produced comparable bond strength to that of a multistep Panavia F2.0.

Tuberculous brain abscess and subdural empyema in an immunocompetent child: Significance of AFB staining in aspirated pus.

Tuberculous brain abscess and subdural empyema are extremely rare manifestations of central nervous system tuberculosis. Here, we report a case of an 11-year-old immunocompetent child who developed temporal lobe abscess and subdural empyema following chronic otitis media. A right temporal craniotomy was performed and the abscess was excised. The Ziehl Nielsen staining of the aspirated pus from the temporal lobe abscess yielded acid fast bacilli. Prompt administration of antituberculous treatment resulted in complete recovery of the child. Even though the subdural abscess was not drained, we presume that to be of tubercular aetiology. Ours is probably the first case of brain abscess and subdural empyema due to Mycobacterium tuberculosis reported in the same child. This case is being reported because of its rarity and to stress the importance of routine staining for tubercle bacilli in all cases of brain abscess, especially in endemic areas, as it is difficult to differentiate tuberculous from pyogenic abscess clinically as well as histopathologically.

Immune responses to recombinant proteins of Mycobacterium leprae.

Identification of antigenic determinants of the polar immune response in leprosy may illuminate both protection and pathogenesis. Thirty subjects were studied (22 with polar disease and 8 healthy controls who were heavily exposed but disease-free) by assaying the proliferative, interferon (IFN)-gamma, and antibody responses to recombinant antigens of Mycobacterium leprae (10, 28, 36, and 65 kDa). The 10-kDa antigen elicited IFN-gamma production from all tuberculoid (TT) and borderline tuberculoid (BT) patients but little from controls, lepromatous (LL), or borderline lepromatous (BL) patients (P<.05). Production of 65-kDa-specific IFN-gamma was higher in TT/BT than in controls or LL/BL patients (P<.006). All subjects produced 65-kDa-specific antibody, but it was higher in LL/BL patients than in healthy controls, whose responses were higher than in TT/BT subjects (P=.035). The 36-kDa antibody responses were selectively increased in LL/BL subjects (P<.02). The intermediate phenotype of the controls suggests that M. leprae-specific production of IFN-gamma may contribute to pathology and to protection in leprosy.

Feasibility studies of large scale production of human anti-tetanus toxoid monoclonal antibodies.

The feasibility of large scale production of human anti-tetanus toxoid monoclonal antibody for therapeutic use was evaluated using a human heterohybridoma. The effects of duration of subculture, transition from static to agitated culture conditions and the level of serum concentration were studied. The level of antibody secreted by the clone decreased with increasing length of subculture and decreasing serum concentration. The clone exhibited heterogeneity in expression of surface IgG after 2 or 7 weeks of subculture in static culture conditions irrespective of the serum concentration. However, a prolonged duration of subculture (9 weeks) in 3% serum medium had an effect on the expression of surface IgG both in static and agitated culture conditions. With respect to total (surface and intracellular) IgG, two distinct cell populations were observed. On long term subculture (9 weeks) in low serum medium (3% FCS), there was a decrease in the population which was the high synthesizer. In addition, when these cells were cultivated in agitated spinner flasks, a defect in secretion of antibodies was observed. Thus a general fall in the amount of antibody in the supernatant of agitated cultures was due to decrease in antibody synthesis as well as the defect in secretion of antibodies.

A study of culture positive multidrug resistant enteric fever--changing pattern and emerging resistance to ciprofloxacin.

The present prospective study was carried out to observe the changing trends in the clinical pattern and multidrug resistance in typhoid fever. Fever was the main presenting feature. Other associated features were headache, vomiting, diarrhoea, altered sensorium and jaundice. Out of 78 patients, one patient died due to enteric encephalopathy and other due to septicaemia with peripheral circulatory failure. 12 patients responded to chloramphenicol and gentamycin. 51 patients responded to ciprofloxacin, while remaining 9 patients responded to combination of cefotaxime and amikacin. Three patients showed in vitro resistance to ciprofloxacin and two out of these also showed no response in vivo. This study re-emphasises the changing pattern, prolonged course and role of quinolones especially ciprofloxacin in the management of drug resistant typhoid fever, but at the same time indicates that ciprofloxacin is not the drug of choice in all cases of typhoid fever and resistance to it may be seen in some cases, where other drugs have to be used.

Comparison of Siriraj and Guy's Hospital score to differentiate supratentorial ischaemic and haemorrhagic strokes in the Indian population.

In India, 70% of the population does not have access to computerised brain scanning. Siriraj score is a safe and reliable clinical method to asses acute stroke syndrome. 160 patients with acute stroke were analysed by Siriraj and Guy's hospital stroke score simultaneously. CT Scan was performed in all and subarachnoid haemorrhage was excluded. Ninety two patients (57.5%) had infarction and 68 (42.5%) had haemorrhage. Siriraj score formula revealed haemorrhage in 53 (80%) and infarction in 78 (83%), while in the rest the results were equivocal or incorrect. Guy's hospital score revealed haemorrhage in 45 (66%) and infarction in 59 (69%). Clinical features are also helpful in differentiating infarction from haemorrhage, but the accuracy is not as high as with Siriraj score and secondly Siriraj score is a very simple formula in comparison to Guy's score.

Oxidative stress and antioxidant defence mechanism in Plasmodium vivax malaria before and after chloroquine treatment.

The protection of Plasmodium vivax-parasitized red blood cells (PRBCs) against activated forms of oxygen was examined in relation to the non-parasitized and chloroquine-treated red blood cells. Increased parasitaemia was found to be accompanied with a decrease in the activities of enzymes of the glutathione system, namely glutathione peroxidase (GPx), glutathione reductase (GRx) and glutathione S-transferase (GTr) in the red blood cells (RBC) lysates. In contrast, however, the total amount of reduced glutathione (GSH) and the content of water-soluble antioxidant vitamin C was increased 2-3 fold over those of control RBCs. Chloroquine-treated red cells contained enzyme activities and antioxidant contents (GSH, vitamin C) comparable to those of control and non-parasitized red cells. Our results therefore indicate the oxidative stress experienced by RBCs during P. vivax infection and that this infection is accompanied with changes in the antioxidant defence system of the host, which are restored to near normal levels after treatment with chloroquine.

Plasmodium falciparum invades human red cells via a parasite produced glycosidase.

This report describes that P. falciparum produces a neuraminidase like activity on invasion into erythrocytes in culture on the basis of biochemical and immunological investigations. This activity in turn modifies the surface glycoprotein receptors of red cells and may be of help in the inhibition of further invasion by merozoites. The characterization of this enzyme activity may help elucidate the mechanism of cerebral malaria.

Histopathological and biochemical changes in the liver and testes of desert gerbil, after repeated exposures of Thimet (phorate).

Intraperitoneal administration of Thimet (0.6 mg/kg) on alternate days for a period of 30 days produced various pathological and biochemical changes in the liver and testes of male gerbils. Histology of the liver showed necrosis, enlarged hepatocytes and fatty degeneration. Histological changes seen in the testes were enlarged interstitium, pyknotic spermatogenic cells, reduction in tubular size and atrophy of Leydig cells. The activities of alkaline and acid phosphatases increased in both liver and testes while that of ATPase decreased significantly. The activity of G-6-Pase decreased in liver but increased significantly in testes. Partial recovery was seen 15 days after termination of Thimet treatment. The activities of acid phosphatase, ATPase of liver and alkaline phosphatase, acid phosphatase, and ATPase of testes did not return to their normal values up to 15 days after stopping the injections.

Histopathological changes induced by quinalphos in the testes and liver of Indian dessert gerbils, Meriones hurrianae (Jerdon).

Single intraperitoneal injection of quinalphos (15 mg/kg body weight) produced several pathological changes in the testes and liver of the Indian desert gerbil, Meriones hurriane (Jerdon). The degenerative changes included testicular atrophy, reduction in tubular size and enlarged interstitium. In the spermatogenic cells, necrosis and karyopycnosis were observed. Hepatic cells revealed cytoplasmolysis, vacuolation and necrosis. The nuclei of the hepatocytes showed karyorrhexis and karyolysis.