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Biomedical subjects

R Krishnamurthy

Publications and source records attributed to R Krishnamurthy.

At least 37 records · Page 2Linked to original sources
PubMed1999

A comparison of two interpretive approaches for the MMPI--A Structural Summary.

We undertook this study to provide empirically derived interpretative recommendations for the MMPI-A Structural Summary through an evaluation of factor elevation patterns. We examined the frequency of single-factor, two-factor, and multifactor elevations in a clinical sample of 363 adolescents receiving inpatient, outpatient, or residential treatment. Two methods of determining factor elevation (a simple majority of scales and subscales within a specific factor with T-score elevations at critical level, versus the mean T score generated by all the scales and subscales for each factor) yielded comparable findings concerning the frequency of factor elevation, permitting reliance on the former, easier-to-use method to define elevation. The most salient two-factor co-elevations were the 3-7 (Disinhibition-Familial Alienation), 2-8 (Immaturity-Psychoticism), 1-5 (General Maladjustment-Health Concerns), and 2-7 (Immaturity-Familial Alienation) patterns. This study also examined whether factor pattern elevations varied as a function of age, gender, or diagnosis. Data analyses revealed no differences between younger (ages 13-14) and older (ages 15-18) adolescents on factor elevation as defined by the first criterion. However, significant differences were found between boys and girls on Factors 3 (Disinhibition) and 5 (Health Concerns). Results also indicated that a larger proportion of depressed adolescents obtained factor elevations on Factors 4 (Social Discomfort) and 5 (Health Concerns) compared to adolescents with conduct disorder diagnoses and other diagnoses. The findings of this study are discussed with reference to recommended procedures for using the Structural Summary in clinical assessment practice.

Adolescent↗
PubMed1999

Regulation of Hoxa2 in cranial neural crest cells involves members of the AP-2 family.

Hoxa2 is expressed in cranial neural crest cells that migrate into the second branchial arch and is essential for proper patterning of neural-crest-derived structures in this region. We have used transgenic analysis to begin to address the regulatory mechanisms which underlie neural-crest-specific expression of Hoxa2. By performing a deletion analysis on an enhancer from the Hoxa2 gene that is capable of mediating expression in neural crest cells in a manner similar to the endogenous gene, we demonstrated that multiple cis-acting elements are required for neural-crest-specific activity. One of these elements consists of a sequence that binds to the three transcription factor AP-2 family members. Mutation or deletion of this site in the Hoxa2 enhancer abrogates reporter expression in cranial neural crest cells but not in the hindbrain. In both cell culture co-transfection assays and transgenic embryos AP-2 family members are able to trans-activate reporter expression, showing that this enhancer functions as an AP-2-responsive element in vivo. Reporter expression is not abolished in an AP-2(alpha) null mutant embryos, suggesting redundancy with other AP-2 family members for activation of the Hoxa2 enhancer. Other cis-elements identified in this study critical for neural-crest-specific expression include an element that influences levels of expression and a conserved sequence, which when multimerized directs expression in a broad subset of neural crest cells. These elements work together to co-ordinate and restrict neural crest expression to the second branchial arch and more posterior regions. Our findings have identified the cis-components that allow Hoxa2 to be regulated independently in rhombomeres and cranial neural crest cells.

Animals↗
PubMed1998

Renal aspergillosis giving rise to obstructive uropathy and recurrent anuric renal failure.

A sixty-year-old previously healthy male patient presented with anuric renal failure of sudden onset. He was detected to have Aspergillus fumigatus fungal balls in the renal pelvis, ureters and bladder which were removed and his renal function improved. He was treated with itraconazole and sent home. Three weeks later he again presented with anuria and renal failure. He had recurrence of the obstruction with the same fungus. The fungal ball was removed, a double 'J' stenting was performed and he was treated with amphotericin B and itraconazole. Hence we report a previously healthy patient with no evidence of immunosuppression presenting an obstructive anuric renal failure due to isolated renal aspergillosis.

Acute Kidney Injury↗
PubMed1997

Comparison of two repositioning devices used during radiation therapy for Hodgkin's disease.

PURPOSE: Patients irradiated for Hodgkin's disease are fixed in an immobilization cradle to improve repositioning. In the early 1990s, we changed our cradle system from a "short" upper torso cradle to an extended near-total body cradle that also includes the lower torso and thighs. In this study, we assess the impact of the extended cradle on the reproducibility of patient repositioning during irradiation of Hodgkin's disease. METHODS AND MATERIALS: A total of 782 port films of 56 patients treated immediately before and after the change-over were studied to assess positioning reproducibility. Patients treated prior to 1993 were positioned in the short cradle, while those treated 1993 and later were positioned in the extended cradle. All treatment were delivered via anterior and posterior fields and treatment areas above and below the diaphragm were considered separately and together. All treatment fields were simulated and the field shape was designed on anterior and posterior radiographs. Discrepancies in field placement between the simulation radiographs and subsequent port films were noted by a radiation oncologist and requests for position adjustment (both translational and rotational shifts) were noted. The number, magnitude, and direction of any physician-requested position adjustment on port films were retrospectively reviewed. For the purpose of scoring the frequency of field misplacements, when an adjustment was noted on two port films taken during the same treatment session (i.e., a left shift on both an anterior and a posterior port film), it was scored as only one event. A two-tailed chi-square test was used to compare the differences in requested shifts in the two patient groups. RESULTS: The study population consisted of 56 patients (31 short and 25 extended cradle) representing 92 treatment sites. A total of 782 port films representing 450 treatment setups were analyzed (292 above and 158 below the diaphragm). When all port films above the diaphragm (mostly mantle fields) are considered, position adjustments were requested in 13.4% (21 out of 157) of treatment setups with the upper torso cradle and in 5.9% (8 out of 135) of treatment setups with the extended cradle (p = 0.054). When all port films below the diaphragm (mostly paraaortic/spleen and pelvic fields) are considered, position adjustments were requested in 33.8% (27 out of 80) of treatment setups with the upper torso cradle and in 16.7 % (13 out of 78) of treatment setups with the extended cradle (p = 0.056). A reduction in the frequency of both translational and rotational adjustments were seen. When both treatment sites are combined, position adjustments were requested in 20.3% (48 out of 237) of treatment setups with the upper torso cradle and in 9.9% (21 out of 213) of treatment setups when the extended cradle was used (p = 0.0086). CONCLUSIONS: The extended cradle provides superior repositioning of patients undergoing radiation therapy for Hodgkin's disease. Differences observed in setup accuracy in this study underscore the importance of aggressive immobilization of patients with Hodgkin's disease. Increased accuracy of daily setup may provide an opportunity to improve the therapeutic ratio both by increased likelihood of tumor control and decreased risk of normal tissue complications.

Equipment Design↗
PubMed1997

Impact of cradle immobilization on setup reproducibility during external beam radiation therapy for lung cancer.

PURPOSE: To compare the setup accuracy during fractionated radiation therapy for two patient groups with lung cancer treated with and without an immobilization cradle. METHODS: Three hundred ninety-seven port films from 30 patients immobilized in the Alpha Cradle were compared with 329 port films from 30 patients who were not immobilized with the cradle. All patients were treated with curative intent for nonmetastatic lung cancer. The frequency of physician-requested isocenter shifts were compared in the two groups using a two-tailed chi-square test. Initial port films taken on the first day of treatment, routine films taken usually weekly during radiation therapy, and requested films taken after a requested shift were considered separately. The immobilization device consisted of a custom-made foam cradle that extended from above the head to the knees. Patients were generally treated with their arms above their heads, and treatment setup marks in the immobilized patients were placed on both the patients' skin and the immobilization cradle. For the noncradle patients, setup marks were placed only on the patients' skin. RESULTS: For the routine films, the frequency of physician-requested isocenter shifts was lower in immobilized patients than in the nonimmobilized group (p = 0.139). Most of this reduction was seen on oblique fields (p = 0.038). No benefits were seen among initial or requested films. The two groups were well balanced with regard to stage, age, field size, and total dose. CONCLUSIONS: The use of aggressive immobilization improves the setup reproducibility in patients receiving external beam radiation therapy for lung cancer, especially during treatment with oblique fields. This improvement in treatment accuracy might improve the therapeutic ratio.

Humans↗
PubMed1997

MMPI-A and Rorschach indices related to depression and conduct disorder: an evaluation of the incremental validity hypothesis.

This investigation extends the earlier research by Archer and Gordon (1988) by examining the extent to which combining indices from the newly released MMPI-A and the revised Rorschach Comprehensive System furnishes incremental validity in terms of improved diagnostic prediction. The predictive accuracy of selected MMPI-A and Rorschach variables conceptually related to diagnoses of depression and conduct disorder were compared in a clinical sample of 152 adolescents. Results of multivariate analyses of variance revealed some significant differences between diagnostic groups on several MMPI-A scales, and 1 significant difference on the Rorschach involving the Vista variable. Stepwise discriminant function analyses resulted in 2 MMPI-A scales and 2 Rorschach variables that collectively accounted for a small proportion of variance in the diagnosis of depression, and 3 MMPI-A scales that accounted for a significant component of variance in the conduct disorder diagnosis. Classification accuracy results indicated that the hit rate for depression diagnosis did not improve using an optimal linear combination of the 4 variables over the rates produced by the single use of either the MMPI-A Depression content scale (A-DEP) or Scale 2. For the conduct disorder diagnosis, the optimal linear combination of MMPI-A Conduct Problems (A-CON), Cynicism (A-CYN), and Immaturity (IMM) scales served as the best predictor, and no Rorschach variables contributed significantly to classification accuracy. Our results replicated the findings of Archer and Gordon (1988) in indicating that the combined use of MMPI-A and Rorschach variables does not appear to produce incremental increases in accuracy of diagnostic classification.

Adolescent↗
PubMed1993

Combining the Rorschach and the MMPI in the assessment of adolescents.

We examined empirical findings related to the integration of the Rorschach and the MMPI in assessing adolescents. Intercorrelations between 50 Rorschach variables and the 13 MMPI basic scales are reported for a clinical sample of 197 adolescents. Significant correlations only slightly exceeded the number expected by chance. A review of six additional studies of adolescent samples also generally revealed either very modest or nonsignificant relationships between the Rorschach and the MMPI. These findings leave open the possibility that combining data from the two instruments may increase incremental validity, an issue that should be assessed by using multivariate analyses. Guidelines for integrating Rorschach and MMPI data in clinical practices with adolescents are provided.

Adolescent↗
PubMed1993

A Review of MMPI and Rorschach interrelationships in adult samples.

The MMPI and Rorschach are consistently ranked among the most widely used psychological assessment instruments across adolescent and adult clinical settings. Although there is an extensive research literature available on each instrument individually, relatively little research attention has been focused on the interrelationships between these measures. This article reviews the literature derived from 37 studies that have reported interrelationships between MMPI and Rorschach variables in adult populations. The results of these studies generally indicate limited or minimal relationships between the MMPI and Rorschach. A number of methodological issues, however, prevent drawing firm conclusions from the literature at this time. Directions for future research are discussed, including consideration of issues related to sources of alpha and beta error and the need for studies examining the incremental validity of combinations of Rorschach and MMPI data in prediction to relevant external criteria.

Journal Article↗
PubMed1990

Accumulation of low molecular weight (bleomycin detectable) iron in bone marrow cells of rats after benzene exposure.

An accumulation of low molecular weight (LMW) bleomycin detectable iron in the bone marrow was observed after administration of benzene (IP 0.5 ml/kg, daily) for 5 and 10 days in female albino rats. However, this LMW iron was not detectable in the bone marrow of rats from the control group. Studies of bone marrow fractionation showed that the maximum accumulation of this LMW iron was in the mitochondrial fraction. An increase in the activity of superoxide dismutase and lipid peroxidation was also noticed in the benzene exposed groups.

Animals↗
PubMed1989

Modulation of benzene toxicity by polyinosinic-polycytidilic acid, an interferon inducer.

Repeated intraperitoneal administration of benzene (1.0 ml/kg body wt.) for 3 days produced leucopenia, lymphocytopenia and significantly decreased body wt. (P less than 0.001) and organ weights of thymus (P less than 0.001) and spleen (P less than 0.001) in female albino rats. Total iron content, lipid peroxidation and superoxide dismutase activity of the liver and bone marrow were significantly increased as a result of benzene exposure. Low molecular weight (LMW) bleomycin detectable iron content was accumulated in bone marrow, whereas hepatic LMW iron was not detectable after benzene intoxication to rats. Prior administration of single dose (250 micrograms/100 g body wt.) of Poly IC, an interferon inducer with immunomodulating potential was found to be ameliorate some of the adverse effects of benzene as well as restoration of hepatic architecture histologically. Superoxide dismutase activity, lipid peroxidation, total iron content and LMW iron content (bone marrow) were normalised. Pretreatment of animals with Poly IC was able to enhance the SRBC antibody titre in benzene-treated animals. This study suggests that the beneficial effects of Poly IC in the amelioration of the acute toxicity of benzene has clinical significance.

Animals↗
PubMed1989

The performance of three cultivars of rice grown near to, and distant from, a fertiliser plant.

The effects of three cultivars, two water regimes and two rates of applying nitrogen fertilisers were tested when studying the performance of rice (Oryza sativa L.) near to, and distant from, a fertiliser plant emitting atmospherically dispersed pollutants. The atmosphere near the fertiliser plant had average daily peak concentrations of 144 and 210 microg m(-3) of SO(2) and NO(2), respectively. Growth was less near to, than at a distance from, the fertiliser plant. On average it was decreased by water stress while the effects of different amounts of nitrogen fertiliser were variable. Whilst there were a number of interactions involving nitrogen and water treatments, the most consistent were associated with the responses of the three cultivars at the two locations. The three cultivars performed similarly at the unpolluted control site, but there were major differences at the polluted site. These were most clearly exemplified by changes in the proportion of dry matter allocated to yields of grain and straw. At the unpolluted site, grain accounted for about 30% of the combined yields of grain and straw. At the polluted site, grain accounted for 1, 23 and 31% of the combined grain and straw yields of cultivars CO 43 (the most sensitive), TKM 9 and GR 3 (the most tolerant). Grain yields were closely related to numbers of filled grains per plant. At the polluted site, 98% of grains failed to develop in CO 43, whereas in GR 3, the number of panicles, and therefore the potential number of grains, was significantly enhanced.

Journal Article↗
PubMed1989

Polyamines as modulators of salt tolerance in rice cultivars.

The effect of NaCl on the endogenous levels of diamine, putrescine and polyamines, spermidine and spermine, was studied in the shoot system of salt-tolerant and salt-sensitive lines of rice (Oryza sativa L.) cultivars during three growth stages. Salt stress increased the levels of diamine and polyamine in varying degrees among nine rice cultivars investigated. Salt tolerant AU1, Co43, and CSC1 were effective in maintaining high concentrations of spermidine and spermine, while the content of putrescine was not significantly altered in all the growth stages when plants were exposed to salinity. The salt sensitivity in rice was associated with excessive accumulation of putrescine and with low levels of spermidine and spermine in the shoot system of salt-sensitive cultivars Co36, CSC2, GR3, IR20, TKM4, and TKM9 under saline condition. One of the possible mechanisms of saline resistance was observed to be due to the highly increased polyamines against the low increase in diamines. Alternatively, the salt sensitivity could be due to high increase of diamines and an incapacity to maintain high levels of polyamines.

Journal Article↗