Connective eccentricity index: a novel topological descriptor for predicting biological activity

A simple, adjacency-cum-path length based, topological descriptor termed the connective eccentricity index has been conceptualized and its discriminating power investigated with regard to antihypertensive activity. A data set consisting of 81 derivatives of N-benzylimidazole was selected for the present investigation. These derivatives are potent, competitive, and nonpeptide angiotensin II receptor antagonists. The value of connective eccentricity index for each derivative was computed and active range identified. Subsequently, each derivative was assigned a biological activity that was compared with the reported antihypertensive activity. The results obtained using connective eccentricity index were better than the corresponding values obtained using Balaban's mean square distance index. The accuracy of prediction was found to be about 80% in the active range using connective eccentricity index.

Increased hyaluronidase expression in more aggressive prostate adenocarcinoma

Tumor metastasis involves a complex sequence of cellular and biochemical events of which tumor cell penetration through the basement membrane is an essential component. Disruption of basement membrane integrity by hyaluronidase has been implicated in the development of locally advanced and metastatic carcinoma. This investigation correlates hyaluronidase expression with pathologic prognostic variables for prostate adenocarcinoma. Paraffin samples (n=9) of patients receiving prostatectomies for clinical stage B adenocarcinoma were evaluated. RT-PCR was utilized to detect the presence of hyaluronidase. These results were correlated with the histological assessment of each sample. Gleason score was significantly higher in patients with RT-PCR detectable hyaluronidase (mean +/- SD 7.25+/-1.8 versus 4.17+/-1.0; p<0.05). Histological evidence of perineural invasion was seen in 83% of the specimens with detectable hyaluronidase, whereas none was found in hyaluronidase negative samples (p<0.05). A trend was seen between hyaluronidase and capsular invasion with 33% hyaluronidase positive tumor exhibiting evidence of capsular invasion, while no evidence in the hyaluronidase negative tumor. These data suggest that hyaluronidase may be involved in prostate adenocarcinoma progression and metastasis.

Alcohol and drug use in victims of life-threatening trauma

OBJECTIVE

Alcohol and drug use has been implicated as a contributing factor to all types of trauma. This investigation seeks to determine the prevalence of alcohol and drug use in patients who are victims of life-threatening injuries and the association of alcohol and drug use with intentional trauma.

METHODS

The Medical Center of Louisiana at New Orleans (Charity Campus) trauma registry was used to identify patients sustaining life-threatening injuries that presented to our American College of Surgeons Level 1 trauma center over a 6-month period. Serum ethanol levels and urine toxicology were assessed at initial presentation for all patients.

RESULTS

A total of 557 patients were evaluated. Seventy percent (n = 319) of tested patients (n = 450) had positive serum ethanol and/or urine toxicology results. Male gender (75% vs. 55%; p < 0.001) was associated with positive screens; ethnicity was not. No difference in hospital days or mortality was seen between positive and negative screens. Victims of intentional trauma showed a higher percent of positive screens (80% vs. 63%; p < 0.005).

CONCLUSION

These data suggest that alcohol and drug use is associated with life-threatening injury, especially intentional injury. Prevention of substance abuse is essential for the prevention of trauma.

Changes in compliance predict pulmonary morbidity in patients undergoing abdominal plication

The incidence and severity of the effects of pulmonary compliance changes were investigated in patients undergoing abdominal plication surgery. A total of 20 healthy adults scheduled for abdominal plication surgery who had no significant history of pulmonary disease and 20 adults scheduled for nonabdominal, nonthoracic surgery (control group) underwent general endotracheal anesthesia; neuromuscular blockade was confirmed with electrical twitch monitoring. Before abdominal plication, the mean airway compliance was measured under total neuromuscular blockade at 33.4 +/- 2.1 ml/cm water, which was not significant when compared with control patient values. After abdominal plication was performed, the mean airway compliance was remeasured under total neuromuscular blockade; it was significantly decreased at 24.0 +/- 1.8 ml/cm water when compared with values for control patients (32.6 +/- 1.6 ml/cm) and with preplication values. Patients with airway compliance changes of less than 4 ml/cm water (when compared with preplication pulmonary mechanics) had far less incidence of atelectasis, requirements for supplemental oxygen at 24 hours or longer, or hypoxia when compared with patients with compliance changes of greater than 4 ml/cm water. Patients with compliance changes greater than 9 ml/cm water had the highest incidence of pulmonary morbidity. These data suggest that significant changes in pulmonary compliance occur after abdominal plication and that these airway compliance changes are associated with a clinically increased incidence of pulmonary morbidity in the postoperative period.

Association of hyaluronidase and breast adenocarcinoma invasiveness

Hyaluronic acid (HA) is a component of the extracellular matrix (ECM) that exists as a high molecular weight polymer composed of alternating disaccharides, D-glucuronic acid and N-acetyl D-glucosamine. The interaction of hyaluronidase with HA results in the disruption of basement membrane integrity and produces an angiogenic response that has been implicated in tumor invasiveness and metastasis. Although hyaluronidase is present in several neoplasms, levels of hyaluronidase expression in breast cancer are not known. This investigation defines the correlation of elevated levels of hyaluronidase with breast adenocarcinoma invasiveness. Utilizing RT-PCR, RNA was extracted from paraffin embedded tissues (n=6) of patients diagnosed with fibrocystic breast changes, ductal carcinoma in situ (DCIS), and invasive adenocarcinoma. After constructing cDNA primers for base pairs 504 and 759 of the PH-20 gene (which is homologous to the hyaluronidase gene), PCR was performed and the products were visualized with ethidium bromide using gel electrophoresis. Invasive breast adenocarcinoma had a significantly higher level of hyaluronidase expression compared to other breast tissue samples; (32+/-15 vs. 8+/-3; p<0.03). Elevated levels of hyaluronidase correlated with invasive breast adenocarcinoma. Our data suggests that elevated levels of hyaluronidase are associated with breast adenocarcinoma invasive potential. Hyaluronidase may play an integral role in breast cancer invasion and metastasis.

Esophageal Doppler ultrasound monitor versus pulmonary artery catheter in the hemodynamic management of critically ill surgical patients

BACKGROUND

The pulmonary artery (PA) catheter has been used to determine hemodynamic indices; however, it has recently been criticized. This study was undertaken to evaluate an esophageal Doppler monitor (EDM) as a possible replacement for PA catheter in critically ill, mechanically ventilated patients.

METHODS

EDM and PA catheters were placed in patients in the surgical intensive care units (n = 14, 118 matched sets of data). PA catheter and EDM measurements, including corrected flow time (FTc,) a measure of preload, were obtained. Pearson correlation (r) was analyzed to compare PA catheter and EDM measurements, and a nonlinear regression model was used to describe Starling Relationships.

RESULTS

Cardiac output correlated between EDM and PA catheter (r = 0.6; p < 0.001). FTc correlated more strongly with cardiac output than did pulmonary capillary wedge pressure. (FTc: r2 = 0.27; p < 0.001; cardiac output: r2 = 0.04; p = 0.06).

CONCLUSION

Corrected flow time is a better indicator of preload than pulmonary capillary wedge pressures. EDM seems to be at least as useful as PA catheter in managing the hemodynamic status of critically ill surgical patients.

Superpendentic index: a novel topological descriptor for predicting biological activity

A simple highly degenerating, pendenticity based, topological descriptor termed as superpendentic index has been conceptualized and its discriminating power investigated with regard to antiulcer activity. A data set consisting of 128 analogues of 4-substituted-2-guanidino thiazoles was selected for the present study. These analogues are reversible, competitive, and selective inhibitors of gastric H+,K(+)-ATPase enzyme. The value of superpendentic index of each analogue in the data set was computed and active range was identified. The biological activity assigned to each analogue using superpendentic index was subsequently compared with the reported in vitro and in vivo inhibitory activities. The accuracy of classification of analogues based on in vivo activity was found to be 82% in the active range using superpendentic index.

Comparison of simulated patient and didactic methods of teaching HIV risk assessment to medical residents

INTRODUCTION

Physicians need to be well trained in HIV risk assessment interview skills. Little has been written in the literature concerning training methods for this specialized interview.

METHODS

One model to teach the HIV risk assessment interview has been developed and has been used to teach third-year medical students. We compared this interactive model, which uses simulated patients to teach HIV Risk Assessment, to a didactic one. Twelve medical residents were taken through either the interactive session or the didactic session. Pre-post changes from questionnaires were calculated to determine any differences in sessions. Also, Objective Structured Clinical Examinations (OSCEs) were used to grade all residents 2 weeks after their sessions.

RESULTS

All pre-post changes were calculated and no statistically significant differences were seen (P > 0.50). OSCE interpersonal skills scores and content scores were calculated. The interactive group had statistically significantly higher scores (P < 0.05).

CONCLUSION

The data supports the conclusion that an interactive method is more effective to use to train HIV risk assessment interview skills to medical residents when compared to the didactic method.

Mitral valve replacement in Sickle C disease using intraoperative exchange transfusion

Sickle C (SC) disease is a relatively uncommon hematologic disorder that poses special challenges when the patient requires a major surgical procedure. In particular, those who have a history of hemolytic crises require some type of intervention, usually homologous transfusion, to decrease the level of circulating hemoglobin S (HbS) and prevent intraoperative sickle crisis. We describe a 25-year-old man with SC disease and a history of multiple sickle cell crises who underwent mitral valve replacement using intraoperative exchange transfusion to decrease his HbS level from 53% to 7%.

Percutaneous endoscopic gastrostomy in the elderly: complications (review)

Due to varying disease processes, the elderly may have limited oral access to their otherwise intact gastrointestinal tract. In such individuals, the intact gastrointestinal tract must be accessed in other ways. Until the early 1980s, choices were limited to temporary solutions such as the nasogastric tube or to long operative procedures such as the operative gastrostomy tube. The introduction of percutaneous endoscopic gastrostomy (PEG) allowed a quick, safe, and cheap procedure as an option. While PEG tubes have been used to help many of the elderly with their nutritional needs, they are not without risks. Below is a review of the literature concerning PEG complications in the elderly.

Apical and basolateral Ca(2) channels modulate cytosolic Ca(2)+ in gallbladder epithelia

Gallstone formation is associated with altered gallbladder (GB) ion transport and increased concentration of GB bile Ca2+. Recent studies show that increased cytosolic Ca2+ ([Ca2+]i) stimulates GB Cl- secretion. However, the mechanism by which extracellular Ca2+ ([Ca2+]e) enters the cytosol remains unclear. We tested the hypothesis that entry of [Ca2+] into cytosol occurs via apical and basolateral membrane Ca2+ channels. Prairie dog GBs were mounted in Ussing chambers, standard electrophysiologic parameters were recorded, and unidirectional Cl- fluxes (J, microEq x cm(-2) x hr(-1) were measured using 36Cl at various mucosal Ca2+ in the absence or presence of mucosal lanthanum (La3+), a non-diffusible Ca2+ channel blocker. Serosal [Ca2+]e was maintained at trace levels. In the absence of mucosal La3+, short circuit current (Isc) showed a positive correlation with mucosal [Ca2+]e as represented by a second order polynomial equation (y = 4.1 + 2.5x - 0.73x(2), r = 0.68, P < 0.001). In contrast, unidirectional mucosa to serosa Cl flux (JCl/ms) was inversely correlated with [Ca2+] (y = 47.9 - 8.7x + 0.9x(2), r = 0.51, P <.05) Addition of 1 mM mucosal La3+ blunted the effects of [Ca2+]e on electrophysiologic parameters and JCl/ms. However, basolateral repletion with 5 mM Ca2+ reverses the blocking effects of La3+ on JCl/ms. These data suggest that [Ca2+]e enters the cytosol via apical and basolateral Ca2+ channels. We conclude that GB apical Ca2+ channels may represent a pathway for biliary Ca2+ entry into the cell and therefore may represent an important regulatory pathway for GB ion transport during gallstone formation.

Structure-activity study on antiulcer agents using Wiener's topological index and molecular connectivity index

The relationship of Wiener's topological index and molecular connectivity index with antiulcer activity of a series of 4-substituted-2-guanidino thiazole analogs has been investigated. The values of Wiener's topological index and molecular connectivity index of 128 compounds were computed and active ranges were identified. The activity assigned to each analog using these topological descriptors was subsequently compared with the reported in vitro and in vivo activities against gastric hydrogen-potassium stimulated adenosine triphosphatase (H+K(+)-ATPase) enzyme. Predictions with an accuracy of the order of approximately 89% were observed with regard to in vivo activity using these topological indices.

Structure-activity study on antiinflammatory pyrazole carboxylic acid hydrazide analogs using molecular connectivity indices

The relationship between molecular connectivity indices and the antiinflammatory activity of a series of pyrazole carboxylic acid hydrazide analogs has been investigated. The values of molecular connectivity index, valence molecular connectivity index, and a modified index, termed as atomic molecular connectivity index for 76 compounds, were computed and active ranges were identified. Each compound was assigned an activity which was subsequently compared with the reported activity against lipoxygenase enzyme. Predictions with a degree of accuracy above 80% were observed using the valence molecular connectivity index.

Structure-activity study on anticonvulsant (thio) hydantoins using molecular connectivity indices

The relationship between molecular connectivity indices and anticonvulsant activity of a series of hydantoin/thiohydantoin analogs has been investigated. The values of molecular connectivity index and valence molecular connectivity index of 82 compounds were computed and active ranges were identified. The activity assigned to each analog using these topological descriptors was subsequently compared with the reported activity against maximal electroshock convulsions. Predictions with high degree of accuracy were observed using these indices.

Structure-activity study on antiviral 5-vinylpyrimidine nucleoside analogs using Wiener's topological index

The relationship between Wiener's topological index and the antiviral activity of a series of 5-vinylpyrimidine nucleoside analogs has been investigated. Values for more than 100 compounds were computed, and an active range was identified. The predicted activity of each compound was compared with reported antiviral activity against herpes simplex virus type I. Due to significant correlation between antiviral activity and Wiener's topological index, it was possible to predict antiviral activity with an accuracy of approximately 83%.

Union instability and fertility in three Caribbean societies

This paper examines empirically the relationship between sexual union instability and fertility in three English-speaking Caribbean societies, Guyana, Jamaica and Trinidad/Tobago, using data collected in the World Fertility Survey Programme. An index of cumulative fertility, the duration ratio, that controls for the biological effects of age and age at first union is used as the dependent variable in a multiple regression analysis. The statistical findings are in general agreement with previous research that has found a positive association between fertility and the number of sexual unions in these societies. However, the estimated fertility effect of belonging to different union types (i.e. married, common-law and visiting) is not uniform across the three societies.