Sociodemographic and clinical correlates of P-A-I-N

Rules to clarify MMPI profiles into four types (P-A-I-N) observed commonly in chronic pain patient populations were tested to determine if resulting average profiles matched computer-algorithm derived prototypes. Close matches were obtained, suggesting that the rules could be used in the ordinary pain clinic setting to look for type x treatment interactions. Seven clinical variables differentiated the types. Type P and N were most different from one another, and Types A and I represented poles on an optimism-pessimism dimension.     

Stereothresholds for moving line stimuli for a range of velocities

This study examined the influence of lateral target motion on the stereothresholds for bright vertical lines at a range of velocities. Stimuli were presented for 200 ms with horizontal velocities from 0 to 12 deg/s. Observers' horizontal eye movements were recorded on additional trials, and confirmed that the velocity of retinal image motion closely matched the velocity of the stimulus. In three auxiliary experiments, stereothresholds were measured (1) after equating the detectability of targets that moved at different velocities, (2) for moving and stationary stimuli with durations between 20 and 200 ms, and (3) for stationary stimuli presented at eccentricities of 0.6 and 1.2 deg. The results indicate that stereothresholds are unaffected by velocities up to approximately 2 deg/s, but worsen in proportion to the velocity at higher speeds. The results of our auxiliary experiments demonstrate that the increase in stereothresholds during image motion cannot be attributed primarily to a reduction in the detectability of the stimulus, a decrease in the effective exposure duration, or non-foveal viewing. We conclude that the elevation of stereo thresholds during lateral motion is consistent with a shift in the sensitivity of the visual system toward lower spatial frequencies as a result of motion blur.     

Outcome of corneal transplant rejection: a 10-year study

PURPOSE: To study the incidence of graft rejection and the predictive factors for its reversibility. METHODS: It is a retrospective study of 1927 consecutive penetrating keratoplasties performed between January 1990 and January 2000 with more than 6 months follow up. A total of 224 rejection episodes were noted in 183 patients. Of these, 184 first rejection episodes were included in this study. RESULTS: The incidence of first rejection episode was 9.55%. Of patients 87% were symptomatic during the episode with vision loss being the commonest. The average time of onset of rejection was 15.25 +/- 14.4 months (median 11.7 months). In total, 53.3% of rejections occurred within 1 year after surgery. Of the patients who completed minimum 3 months follow up after the rejection episode, the rate of reversibility was 63.3%. Major predictive factors for a poor outcome after rejection were repeated grafting and associated anterior vitrectomy during surgery. The reversibility of the episode did not differ significantly with the modality of treatment used, but treatment with intravenous steroids within 7 days of onset of rejection may have a role in reducing the recurrences of rejection episodes, thus increasing the graft survival. CONCLUSION: Regrafts and associated anterior vitrectomy were significant risk factors for a poor outcome following rejection episode.     

Idiopathic infantile arterial calcification with thrombotic microangiopathy--a unique case

Idiopathic Infantile Arterial Calcification (IIAC) is a rare syndrome of unknown cause characterized by disruption and calcification of the internal elastic laminae of fetal arteries with calcium deposits leading to fibrosis and occlusion of the arteries. The diagnosis is often made at post-mortem examination. However, in a few cases it has been detected prenatally as in this case. Fewer than 10 cases of antenatal detection of this condition have been reported in the literature. In our case, thrombotic microangiopathy was an added feature, which has not been reported thus far in the literature to the best of our knowledge.     

The factors affecting outcome after non-vascular bone grafting and internal fixation for nonunion of the scaphoid

This study identified variables which influence the outcome of surgical management on 126 ununited scaphoid fractures managed by internal fixation and non-vascular bone grafting. The site of fracture was defined by a new method: the ratio of the length of the proximal fragment to the sum of the lengths of both fragments, calculated using specific views in the plain radiographs. Bone healing occurred in 71% (89) of cases. Only the site of nonunion (p = 1 x 10(-6)) and the delay to surgery (p = 0.001) remained significant on multivariate analysis. The effect of surgical delay on the probability of union increased as the fracture site moved proximally. A prediction model was produced by stepwise logistic regression analysis, enabling the surgeon to predict the success of surgery where the site of the nonunion and delay to surgery is known.     

Cholera Toxin Production by the El Tor Variant of Vibrio cholerae O1 Compared to Prototype El Tor and Classical Biotypes

Vibrio cholerae O1 El Tor variant strains produced much more cholera toxin than did prototype El Tor strains. The amount of cholera toxin produced by El Tor variant strains both in vitro and in vivo was more or less equivalent to that produced by classical strains.Vibrio cholerae O1 is classified into classical and El Tor biotypes. Among other genetic, biochemical, and physiological differences, each biotype has unique gene sequences encoding cholera toxin B subunit (CTB), that is, classical ctxB and El Tor ctxB. Besides these two prototype biotypes of V. cholerae O1, Nair et al. (9) in 2002 in Bangladesh isolated strains that possess phenotypic properties of both classical and El Tor biotypes carrying classical ctxB. The same group also isolated El Tor strains that had classical ctxB (10). For these new types of strains of V. cholerae O1, we have recently proposed the designations of hybrid and El Tor variants, respectively (13). Subsequent to the isolation of the El Tor variant in Bangladesh by Nair et al. (10), El Tor variant strains were isolated from several countries and areas in Asia and Africa (1, 11, 15-18). In Kolkata, India, we showed that El Tor variant strains appeared in 1990 and that a complete replacement of prototype El Tor strains by El Tor variant strains has occurred since 1995 (14).In this study, we investigated the amount of cholera toxin (CT) produced both in vitro and in vivo by V. cholerae O1 El Tor variant strains isolated in Kolkata during a period from 1996 to 2007. It was found that El Tor variant strains produced a much larger amount of CT than did prototype El Tor strains and that the amount of CT produced by El Tor variant strains was more or less equivalent to that produced by classical strains.V. cholerae O1 strains used in this study are listed in Table ​Table1.1. AKI (3) and Syncase medium (2) were used for culturing the test strains. The rationale for selecting these media was that AKI preferentially supports the production of El Tor CT (3) while Syncase medium is reported to be the best medium supporting the production of CT by the classical biotype (2). Measurement of CT concentration produced by V. cholerae O1 strains was carried out as follows. Each strain was cultured either in AKI medium at 37°C for 20 h without shaking or in Syncase medium at 37°C for 20 h with shaking, and the optical density of the culture was measured at 600 nm (OD₆₀₀). After centrifugation, the supernatants were collected and the concentration of CT (ng/ml/OD₆₀₀) in the samples was measured by bead enzyme-linked immunosorbent assay (ELISA). The method of the bead ELISA employed was essentially that described by Oku et al. (12). In brief, a polystyrene bead (6.5 mm in diameter) was coated with anti-CT IgG and used as a solid phase. The coated bead was first incubated with the sample and then incubated with anti-CT IgG [F(ab′)]-horseradish peroxidase conjugate. Peroxidase activity was determined colorimetrically with 3,3′,5,5′-tetramethylbenzidine as the substrate. The absorbance at 450 nm (OD₄₅₀) was linear between 0 and 0.5, representing CT concentrations of 0 to 20 ng/ml. The sample prepared as described above (the supernatant of the culture of the strain) was appropriately diluted so that the OD₄₅₀ fell in the range of 0.1 to 0.5, and the amount of CT produced by the strain was expressed as ng/ml/OD₆₀₀.

TABLE 1.

V. cholerae O1 strains used