A randomized comparison of sublingual and vaginal misoprostol for cervical priming before suction termination of first-trimester pregnancy

This randomized trial compares the efficacy and side effects of sublingual and vaginal misoprostol for cervical priming before first-trimester pregnancy termination. One-hundred pregnant women between 6 and 12 weeks of gestation opting for termination of pregnancy by suction evacuation were included in this study. The women were randomly allocated into two groups. Group 1 received 400 microg of sublingual misoprostol and group 2 received 400 microg of vaginal misoprostol 2 h prior to suction evacuation. The abortion was carried out by suction evacuation using a Karman's cannula attached to an electrically operated suction machine under intravenous analgesia. Baseline cervical dilatation, duration of the procedure, operative blood loss, side effects and complications were noted in both groups. There was a significant difference between the sublingual and vaginal misoprostol groups with respect to mean cervical dilatation (8.6 mm vs. 6.8 mm, p < 0.05). However, the duration of the procedure (3.03 min vs. 3.16 min) and the amount of blood loss (29 mL vs. 31.2 mL) were not significantly different between the two groups. The women in the sublingual group experienced significantly more shivering and preoperative vaginal bleeding (68% vs. 56%, p < 0.05). None of the women in the two groups had either uterine perforation or excessive hemorrhage. In our study, sublingual misoprostol (400 microg) was significantly more effective in facilitating cervical dilation prior to surgical abortion than vaginal misoprostol.

Re-use of explanted DDD pacemakers as VDD- clinical utility and cost effectiveness

Re-use of DDD pulse generators explanted from patients died of unrelated causes is associated with an additional cost of two transvenous leads if implanted as DDD itself, and high rate of infection according to some studies. We studied the clinical and economical aspects of reutilization of explanted DDD pacemakers programmed to VDD mode. Out of 28 patients who received VDD pacemaker during the period, October 2000- September 2001 in the Department of Cardiology, PGIMER, Chandigarh, 5 poor patients were implanted with explanted DDD pulse generators programmed to VDD mode. Each implantation was planned and carried out according to a standard protocol. The age ranged from 45 to 75 (mean-61) years. The indications for pacing were complete heart block (4) and second degree AV block (1). The clinical profile, costs and complications, if any were noted and followed up at regular intervals. The results were compared with patients who received new DDD pulse generators during this period. The additional cost for the atrial lead was not required in these patients. None of these patients had any local site infection. Compared to the two-lead system, the single lead system provided more rapid implantation and minimized complications associated with placement of an atrial lead. The explanted DDD pacemaker can be safely reused as VDD mode with same efficacy in selected patient population. This is associated with lower cost and complications compared to reimplantation as DDD itself.

Effect of different aspirin doses on platelet aggregation in patients with stable coronary artery disease

BACKGROUND

Aspirin is widely used as an antiplatelet agent in the primary and secondary prevention of cardiovascular disease. In order to spare prostacyclin formation and reduce gastrointestinal side-effects, very low doses of aspirin have been introduced. However, it remains unclear whether these low doses are equally effective with respect to inhibition of platelet aggregation.

AIMS

In a randomized, controlled study in 60 patients with stable coronary artery disease, the effects on platelet aggregation of five doses (50, 80, 100, 162.5 and 325 mg) of aspirin, which are widely used in clinical practice, given for 70 days, were investigated. Two reagents, adenosine diphosphate (ADP) and epinephrine, were used to induce platelet aggregation in platelet-rich plasma. An age- and sex-matched group of people without coronary artery disease served as the control.

RESULTS

ADP- and epinephrine-induced platelet aggregation was 78.2 +/- 12.8% and 76.7 +/- 15.5% of maximum aggregation in the control group. Aspirin inhibited platelet aggregation in a dose-dependent manner. Minimum platelet aggregation was observed at a dose of 325 mg aspirin (27.5 +/- 17.4% with ADP). Doses of 50 and 80 mg aspirin were much less effective in inhibiting platelet aggregation (59.1 +/- 11.4% and 50.3 +/- 12.1% with ADP, respectively). Doses of 100 and 162.5 mg aspirin produced significantly greater inhibition of platelet aggregation than lower doses (36.2 +/- 11.7% and 38.5 +/- 19.8% platelet aggregation with ADP, respectively).

CONCLUSION

Our results demonstrate that doses of aspirin less than 100 mg are not as effective at inhibiting platelet aggregation as doses greater than 100 mg.

Maternal and perinatal outcome in rheumatic heart disease

OBJECTIVES

To study the maternal and perinatal outcome of pregnancies complicated by rheumatic heart disease.

METHODS

A retrospective study was carried out in the cardio-obstetric clinic of the Postgraduate Institute of Medical Education and Research, Chandigarh (India) over a period of 13 years (1987-1999) involving 486 pregnant patients with rheumatic heart disease. Maternal and perinatal outcome was reviewed.

RESULTS

Three hundred and four patients (63.3%) had single valve involvement and mitral stenosis was the most predominant lesion (89.2%). One hundred and seventy one (38.6%) patients had undergone surgical correction prior to the onset of pregnancy. One hundred and thirteen patients (22.6%) were identified as NYHA class III-IV. Mitral valvotomy was performed during pregnancy in 48 patients. The incidence of preterm birth and small for gestational age newborns was 12% and 18.2%, respectively. There were 10 maternal deaths, of which eight patients were NYHA III and IV.

CONCLUSIONS

Rheumatic heart disease in pregnancy is associated with significant maternal and perinatal morbidity in NYHA class III-IV patients.

Calcium binding properties of gamma-crystallin: calcium ion binds at the Greek key beta gamma-crystallin fold

The beta- and gamma-crystallins are closely related lens proteins that are members of the betagamma-crystallin superfamily, which also include many non-lens members. Although beta-crystallin is known to be a calcium-binding protein, this property has not been reported in gamma-crystallin. We have studied the calcium binding properties of gamma-crystallin, and we show that it binds 4 mol eq of calcium with a dissociation constant of 90 microm. It also binds the calcium-mimic spectral probes, terbium and Stains-all. Calcium binding does not significantly influence protein secondary and tertiary structures. We present evidence that the Greek key crystallin fold is the site for calcium ion binding in gamma-crystallin. Peptides corresponding to Greek key motif of gamma-crystallin (42 residues) and their mutants were synthesized and studied for calcium binding. These peptides adopt beta-sheet conformation and form aggregates producing beta-sandwich. Our results with peptides show that, in Greek key motif, the amino acid adjacent to the conserved aromatic corner in the "a" strand and three amino acids of the "d" strand participate in calcium binding. We suggest that the betagamma superfamily represents a novel class of calcium-binding proteins with the Greek key betagamma-crystallin fold as potential calcium-binding sites. These results are of significance in understanding the mechanism of calcium homeostasis in the lens.

A cardiac evoked response algorithm providing automatic threshold tracking for continuous capture verification: a single-center prospective study

BACKGROUND

The AutoCapture algorithm as implemented in Regency and Microny pacemakers (Pacesetter Inc., Sylmar, CA, USA) provides beat-by-beat monitoring of capture based on proper detection of the evoked response, provides high output back-up pulse when loss of capture occurs, performs periodic threshold evaluations and acquires the capture threshold data in a time-based event counter for later retrieval. The safety and efficacy of this algorithm was prospectively evaluated at a tertiary care hospital of north India.

METHODS AND RESULTS

Fifty-four patients (38 males, mean age 66+/-13 years) received a ventricular pacemaker model Regency SC+ with low polarization bipolar lead for high-grade atrioventricular block (n=42) and sick sinus syndrome (n=12). Evoked response and polarization signal were assessed initially at 24 hours postimplant, and follow-up measurements were systematically conducted at week 1 and months 1, 3 and 6. Further evaluation of eligible patients was performed at 6-monthly intervals. Lead implantation parameters were optimum in all patients. At 6 months, the algorithm was functional in 51 patients. The pacing threshold increased to 0.89+/-0.36 V (p<0.001) in the first month and stabilized thereafter. Significant saving of energy was accomplished by a constant output safety margin of 0.3 V instead of the traditional 100%. While the evoked response signal remained stable throughout the study period, the potential signal increased significantly from 0.6+/-0.7 mV to 1.0+/-0.6 mV (p<0.001) in the first month and remained steady subsequently. Back-up pacing in the event of exit block was confirmed in all 25 patients who underwent a 24-hour Holter test. Based on the suggested sense margins, ventricular undersensing was observed in 7 (28%) patients, the majority of whom had competitive cardiac rhythms. An elderly patient with pneumonic illness succumbed to pulmonary embolism at 6 months.

CONCLUSIONS

This large single-center experience on AutoCapture demonstrates the success of this algorithm in low-energy ventricular pacing without compromising the patient's safety.

Transglutaminase-mediated cross-linking of alpha-crystallin: structural and functional consequences

Aggregation and covalent cross-linking of the crystallins, the major structural proteins of the eye lens, increase light scattering by the lens leading to opacification and cataract. Disturbance of calcium homeostasis in the tissue is one of the factors implicated in cataractogenesis. Calcium-activated transglutaminase (TG)-catalyzed cross-linking of some lens proteins has been reported earlier. We show here that alpha-crystallin, a major structural protein in the lens and a member of the small heat shock protein family, is also a substrate for TG-mediated cross-linking, indicating the presence of donor Lys and acceptor Gln residues in the protein. Upon TG-catalyzed dimerization, the secondary and tertiary structures of the protein are altered, and its surface hydrophobicity reduced. The chaperone-like property of the protein, suspected to be one of its functions in situ, is substantially reduced upon such cross-linking. These results, taken together with earlier ones on lens beta-crystallins and vimentin, suggest that TG-mediated events might compromise lens function. Also, since alpha-crystallin occurs not only in the lens but in other tissues as well, such TG-catalyzed cross-linking and the associated alterations in its structure and activity would be of general pathological interest.

Inhibitory effect of silibinin on ligand binding to erbB1 and associated mitogenic signaling, growth, and DNA synthesis in advanced human prostate carcinoma cells

We recently showed the inhibitory effect of a flavonoid antioxidant, silymarin, on erbB1-Shc activation in prostate cancer (PCA) DU145 cells. In the present study, we performed more detailed mechanistic and molecular modeling studies with pure silibinin to assess and define its effect on membrane signaling related to erbB1 activation in human PCA LNCaP and DU145 cells. Studies also were performed to establish the biologic responses toward extracellular signal-regulated protein kinase 1/2 (ERK1/2) activation, cell growth, and DNA synthesis. Treatment of serum-starved cells with various doses of silibinin for 2 h followed by (125)I-epidermal growth factor (EGF) showed 30-75% inhibition in ligand binding and 55-95% inhibition in its internalization in LNCaP cells and 20-64% and 12-27% inhibition in these two events in DU145 cells. Time-response studies showed similar effects. In further studies, treatment of serum-starved cultures with silibinin followed by EGF showed strong inhibitory effects on membrane and cytoplasmic signaling molecules. In the case of erbB1 activation, silibinin showed a 58-75% decrease in LNCaP and a 40-100% decrease in DU145 cells at 50, 75, and 100-microg/mL doses. Inhibitory effects of silibinin also were evident on ERK1/2 activation (20-80% inhibition) in both cell lines. Treatment of serum-starved cultures with silibinin resulted in 20-40% and 30-55% inhibition of LNCaP and DU145 cell growth, respectively, at similar doses after 1-3 d of treatment, and 10-50% cell death in both cell lines. Under 10% serum conditions, identical silibinin treatments resulted in 20-65% inhibition of cell growth in LNCaP and DU145 cells but did not cause any cell death. Similar doses of silibinin treatments for 24 h also resulted in 25-60%, 35-40%, and 36-50% inhibition of DNA synthesis when cells were cultured in 10% serum, totally serum starved, and serum starved plus stimulated with EGF, respectively. Molecular modeling of silibinin showed that it is a highly lipophilic compound, suggesting that it interacts with lipid-rich plasma membrane, including binding with erbB1, thereby competing with the EGF-erbB1 interaction. Because the ligand-erbB1 autocrine-loop is causally involved in advanced and androgen-independent PCA, the observed effects of silibinin and its strong lipophilic nature could be useful in developing this agent for the prevention and therapy of PCA.

A meta-analysis of controlled clinical trials comparing low-molecular weight heparins with unfractionated heparin in unstable angina

BACKGROUND

Unfractionated heparin has been used extensively for the treatment of unstable angina/non-Q wave myocardial infarction but it has several disadvantages. Low-molecular weight heparins are now recommended although they are 3-5 times costlier than unfractionated heparin since they are convinient to administer and do not require activated thromboplastin time monitoring. Whereas enoxaparin, a low-molecular weight heparin, has been demonstrated to be superior to unfractionated heparin, the results of other low-molecular weight heparins have not been so convincing.

METHOD AND RESULTS

Through manual, MEDLINE and EMBASE search, we identified five randomized trials (excluding enoxaparin trials) that compared low-molecular weight heparins with unfractionated heparin in unstable angina. The prespecified efficacy end point of interest included a composite of death, myocardial infarction, recurrent angina and urgent revascularization. The safety end point was taken as a composite of major hemorrhage, minor hemorrhage, thrombocytopenia, allergic reaction and any other adverse event. We calculated odds ratio (95% confidence interval) for each trial for the composite end point, and the pooled odds ratio (95%) confidence interval) was calculated using two established methods of meta-analysis, the Mantel-Haenszel-Peto method and the DerSirmonian-Laird method. Both the methods yielded similar odds ratio (95% confidence interval). Separate odds ratio were calculated for efficacy and safety end points. There was a nonsignificant reduction in the incidence of the composite efficacy end point: the odds ratio (95% confidence interval) was 0.83 (0.70-0.99: p=0.08). The odds ratio (95% confidence interval) for the safety data was 0.78 (0.69-1.26: p=0.33).

CONCLUSIONS

No statistically significant difference was observed when the efficacy and safety of low-molecular weight heparins were compared with those of unfractionated heparin. A cost-effectiveness analysis of low-molecular weight heparins versus unfractionated heparin must be done urgently to establish more firmly the place of low-molecular weight heparins in the management of unstable angina.

A randomized trial to compare the efficacy, safety, cost and platelet aggregation effects of enoxaparin and unfractionated heparin (the ESCAPEU trial)

OBJECTIVE

To compare the efficacy, safety, cost and effects on platelet aggregation of unfractionated heparin and low-molecular weight heparin in unstable angina patients.

PATIENTS AND METHODS

Ninety-three patients with unstable angina were randomized to receive either unfractionated heparin (UFH) or enoxaparin in an open design clinical trial with blinded end point evaluation. The effects of the heparins on platelet aggregation were also compared.

RESULTS

The composite end point of myocardial infarction, cardiac death, recurrent angina and need for intervention was observed in 62% of patients treated with UFH and in 37% of patients treated with enoxaparin (RR 1.7, 95% CI 0.75 to 3.71, p = 0.04). There was no difference in the frequency or severity of adverse events. A cost-effectiveness analysis showed both the heparins to be similar. Platelet aggregation was inhibited to a greater extent by UFH when compared to enoxaparin.

CONCLUSIONS

Enoxaparin appears to be superior in efficacy to UFH and similar to UFH in safety. No difference in costs was detected in this study. The greater inhibition of platelet aggregation observed in the case of UFH compared to enoxaparin indicates that there may be more bleeding complications with UFH.

Purification of myristoylated and nonmyristoylated neuronal calcium sensor-1 using single-step hydrophobic interaction chromatography

Neuronal calcium sensors (NCSs) belong to a family of Ca(2+)-binding proteins, which serve important functions in neurotransmission, and are highly conserved from yeast to humans. Overexpression of the neuronal calcium sensor-1, called frequenin in the fruit fly and in frog, increases the release of neurotransmitters. Studying the functional role of frequenin in mammals and understanding its structural dynamics is critically dependent on the availability of active purified protein. Neuronal calcium sensors like other members of the family share common structural features: they contain four EF-hands as potential binding sites for Ca(2+) and an N-terminal consensus sequence for myristoylation. Previously, recoverin, distantly related to NCSs, has been expressed and purified from Escherichia coli, involving a combination of different chromatographic steps. NCS-1 has earlier been purified adopting a two-step procedure used for recoverin purification. We have overexpressed NCS-1 from rat in its myristoylated and nonmyristoylated form in E. coli and purified it from crude lysates using a single-step hydrophobic interaction chromatography. The purified protein was identified by Western blotting and mass spectrometry and assayed for its ability to bind Ca(2+) using a Ca(2+) shift assay, terbium fluorescence, and Stains-all binding. The present protocol provides a rapid, more efficient and simplified, single-step method for purifying NCS-1 for structural and functional studies. This method can also be applied to purify related proteins of the superfamily.

Anticarcinogenic effect of a polyphenolic fraction isolated from grape seeds in human prostate carcinoma DU145 cells: modulation of mitogenic signaling and cell-cycle regulators and induction of G1 arrest and apoptosis

There is an increasing interest in identifying potent cancer preventive and therapeutic agents against prostate cancer (PCA). In a recent study, we showed that a polyphenolic fraction isolated from grape seeds (hereafter referred to as GSP) that is substantially rich in antioxidant procyanidins exerts exceptionally high preventive effects against tumorigenesis in a murine skin model. In the present study, we investigated the anticarcinogenic effect of GSP against PCA by employing DU145 human prostate carcinoma cells. GSP treatment (10-100 microg/mL doses for 2-6 d) of cells resulted in a highly significant (P < 0.01-0.001) inhibition of cell growth in both dose- and time-dependent manner. Compared with the vehicle, 2 d of GSP treatment resulted in 27, 39, and 76% growth inhibition at 50, 75, and 100 microg/mL doses, respectively, whereas 28-97% and 12-98% inhibition was evident at 10-100 microg/mL doses of GSP after 4 and 6 d of treatment, respectively. These doses of GSP also resulted in dose- and time-dependent cell death (6-50%, P <0.1-0. 001) that was later characterized as apoptotic death. In molecular mechanistic studies, treatment of DU145 cells with GSP at 25-75 microg/mL doses for 24, 48, and 72 h resulted in 77-88%, 65-93%, and 38-98% reduction, respectively (P < 0.001), in phospho-extracellular signal-regulated protein kinase (ERK) 1 and 78%, 19-76%, and 63-71% reduction (P < 0.1-0.001) in phospho-ERK2 levels, respectively. In other studies, similar doses of GSP showed up to 1.9-fold increases in Cip1/p21 and a significant (P < 0.001) decrease in cyclin-dependent kinase (CDK) 4 (up to 90% decrease), CDK2 (up to 50% decrease), and cyclin E (up to 60% decrease). GSP treatment of DU145 cells also resulted in a significant (P < 0.001) G1 arrest in cell-cycle progression in a dose-dependent manner. The growth-inhibitory and cell-death effects of GSP were also observed in another human PCA line, LNCaP. Together, these results suggest that GSP may exert strong anticarcinogenic effect against PCA and that this effect possibly involves modulation of mitogenic signaling and cell-cycle regulators and induction of G1 arrest, cell-growth inhibition, and apoptotic death. Mol. Carcinog. 28:129-138, 2000.

A polyphenolic fraction from grape seeds causes irreversible growth inhibition of breast carcinoma MDA-MB468 cells by inhibiting mitogen-activated protein kinases activation and inducing G1 arrest and differentiation

In recent years, significant emphasis is being placed on identifying naturally occurring cancer preventive and interventive agents. In this regard, a polyphenolic fraction isolated from grape seeds (hereafter referred as GSP) has recently been shown by us and others to prevent tumorigenesis in mouse skin models. Chemical analysis of GSP has shown that it is largely constituted with procyanidins that are strong antioxidants. Breast cancer is the most common invasive malignancy and the second leading cause of cancer-related deaths in United States women. Accordingly, here we investigated the effect of GSP on mitogenic signaling and regulators of cell cycle and apoptosis as molecular targets for the growth arrest, apoptotic death, and/or differentiation of estrogen-independent MDA-MB468 human breast carcinoma cells. Treatment of cells with GSP (at 25-, 50-, and 75-microg/ml doses for 1-3 days) resulted in a highly significant inhibition (90% to complete, P < 0.001) of constitutive activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase1/2 in a dose-dependent manner after 72 h of treatment. Whereas GSP treatment of cells did not show a conclusive effect on MAPK/ JNK1 activation, a moderate to highly significant inhibition (15-70%, P < 0.1-0.001) of constitutive activation of MAPK/p38 was also observed in a dose-dependent manner as early as 24 h of GSP treatment. GSP-treated cells also showed a strong induction (1.7-2.7 fold, P < 0.001) of cyclin-dependent kinase inhibitor Cip1/p21 and a decrease (10-50%, P < 0.1-0.001) in cyclin-dependent kinase 4. Consistent with these findings, GSP-treated cells resulted in their accumulation in G1 phase of the cell cycle in a dose-dependent manner. An irreversible growth inhibition (44-88%, P < 0.001) was also observed in 50 and 75 microg/ml GSP-treated cells in a time-dependent manner. Additional studies assessing the biological fate of GSP-treated cells showed that they do not undergo apoptotic death, as evidenced by a lack of DNA fragmentation, poly (ADP ribose) polymerase cleavage, and apoptotic morphology of the cells. A morphological change suggestive of differentiation was observed in GSP-treated cells that was further confirmed by a significant induction (1.7-2.6 fold, P < 0.001), in both a dose- and time-dependent manner, in cytokeratin 8 protein level, a marker of differentiation. An irreversible growth-inhibitory effect of GSP possibly via terminal differentiation of human breast carcinoma cells suggests that GSP and the procyanidins present therein should be studied more extensively to be developed as preventive and/or interventive agents against breast cancer in humans.

Anticarcinogenic effect of a polyphenolic fraction isolated from grape seeds in human prostate carcinoma DU145 cells: modulation of mitogenic signaling and cell-cycle regulators and induction of G1 arrest and apoptosis

There is an increasing interest in identifying potent cancer preventive and therapeutic agents against prostate cancer (PCA). In a recent study, we showed that a polyphenolic fraction isolated from grape seeds (hereafter referred to as GSP) that is substantially rich in antioxidant procyanidins exerts exceptionally high preventive effects against tumorigenesis in a murine skin model. In the present study, we investigated the anticarcinogenic effect of GSP against PCA by employing DU145 human prostate carcinoma cells. GSP treatment (10-100 microg/mL doses for 2-6 d) of cells resulted in a highly significant (P < 0.01-0.001) inhibition of cell growth in both dose- and time-dependent manner. Compared with the vehicle, 2 d of GSP treatment resulted in 27, 39, and 76% growth inhibition at 50, 75, and 100 microg/mL doses, respectively, whereas 28-97% and 12-98% inhibition was evident at 10-100 microg/mL doses of GSP after 4 and 6 d of treatment, respectively. These doses of GSP also resulted in dose- and time-dependent cell death (6-50%, P <0.1-0. 001) that was later characterized as apoptotic death. In molecular mechanistic studies, treatment of DU145 cells with GSP at 25-75 microg/mL doses for 24, 48, and 72 h resulted in 77-88%, 65-93%, and 38-98% reduction, respectively (P < 0.001), in phospho-extracellular signal-regulated protein kinase (ERK) 1 and 78%, 19-76%, and 63-71% reduction (P < 0.1-0.001) in phospho-ERK2 levels, respectively. In other studies, similar doses of GSP showed up to 1.9-fold increases in Cip1/p21 and a significant (P < 0.001) decrease in cyclin-dependent kinase (CDK) 4 (up to 90% decrease), CDK2 (up to 50% decrease), and cyclin E (up to 60% decrease). GSP treatment of DU145 cells also resulted in a significant (P < 0.001) G1 arrest in cell-cycle progression in a dose-dependent manner. The growth-inhibitory and cell-death effects of GSP were also observed in another human PCA line, LNCaP. Together, these results suggest that GSP may exert strong anticarcinogenic effect against PCA and that this effect possibly involves modulation of mitogenic signaling and cell-cycle regulators and induction of G1 arrest, cell-growth inhibition, and apoptotic death. Mol. Carcinog. 28:129-138, 2000.

Inhibitory effect of a flavonoid antioxidant silymarin on benzoyl peroxide-induced tumor promotion, oxidative stress and inflammatory responses in SENCAR mouse skin

In this communication, we investigate the preventive effect of a flavonoid antioxidant, silymarin, on free radical-generating skin tumor promoting agent benzoyl peroxide (BPO)-induced tumor promotion, oxidative stress and inflammatory responses in SENCAR mouse skin. Topical application of silymarin at a dose of 6 mg prior to BPO resulted in a highly significant protection against BPO-induced tumor promotion in 7,12-dimethylbenz[a]anthracene-initiated SENCAR mouse skin. The preventive effect of silymarin was evident in terms of a 70% reduction (P < 0.001) in tumor incidence, a 67% reduction (P < 0.001) in tumor multiplicity and a 44% decrease (P < 0.001) in tumor volume/tumor. In oxidative stress studies, topical application of BPO resulted in 75, 87 and 61% depletion in superoxide dismutase (SOD), catalase and glutathione peroxidase (GPX) activities in mouse epidermis, respectively. These decreases in antioxidant enzyme activities were significantly (P < 0.005-0.001) reversed by pre-application of silymarin in a dose-dependent manner. The observed effects of silymarin were 18-66, 32-72 and 20-67% protection against BPO-induced depletion of SOD, catalase and GPX activity in mouse epidermis, respectively. Silymarin pre-treatment also resulted in a dose-dependent inhibition (35-87%, P < 0.05-0. 001) of BPO-induced lipid peroxidation in mouse epidermis. In inflammatory response studies, silymarin showed a strong inhibition of BPO-induced skin edema (62-85% inhibition, P < 0.001), myeloperoxidase activity (42-100% inhibition, P < 0.001) and interleukin-1alpha protein level in epidermis (36-81% inhibition, P < 0.001). These results, together with our other recent studies, suggest that silymarin could be useful in preventing a wide range of carcinogen and tumor promoter-induced cancers.

Significant inhibition by the flavonoid antioxidant silymarin against 12-O-tetradecanoylphorbol 13-acetate-caused modulation of antioxidant and inflammatory enzymes, and cyclooxygenase 2 and interleukin-1alpha expression in SENCAR mouse epidermis: implications in the prevention of stage I tumor promotion

The flavonoid antioxidant silymarin is used clinically in Europe and Asia for the treatment of liver diseases and is sold in the United States and Europe as a dietary supplement. Recently we showed that silymarin possesses exceptionally high cancer-preventive effects in different mouse skin carcinogenesis models and affords strong anticancer effects in human skin, cervical, prostate, and breast carcinoma cells. More recently, we showed that the anti-tumor-promoting effect of silymarin is primarily targeted against stage I tumor promotion in mouse skin (Cancer Res 1999;59:622-632). Based on this recent study, in this report, further investigations were made to identify and define the biochemical and molecular mechanisms of silymarin's effect during stage I tumor promotion in mouse skin. A single topical application of silymarin at 3-, 6-, and 9-mg doses onto SENCAR mouse skin followed 30 min later with 12-O-tetradecanoylphorbol 13-acetate (TPA) at a 3-microg dose resulted in a 76-95% inhibition (P < 0.001) of TPA-caused skin edema. Similarly, these doses of silymarin also showed 39-90%, 29-85%, and 15-67% protection (P < 0.05 or 0.001), against TPA-caused depletion of epidermal superoxide dismutase, catalase, and glutathione peroxidase activity, respectively. Pretreatment of mice with silymarin also produced highly significant inhibition of TPA-caused induction of epidermal lipid peroxidation (47-66% inhibition, P < 0.001) and myeloperoxidase activity (56-100% inhibition, P < 0.001). In additional studies assessing the effect of silymarin on arachidonic acid metabolism pathways involving lipoxygenase and cyclooxygenase (COX), similar doses of silymarin showed highly significant inhibition of TPA-caused induction of epidermal lipoxygenase (49-77% inhibition, P < 0.001) and COX (35-64% inhibition, P < 0.01 or 0.001) activity. Western immunoblot analysis showed that the observed effect of silymarin on COX activity was due to inhibition of TPA-inducible COX-2 with no change in constitutive COX-1 protein levels. In other studies, silymarin also showed dose-dependent inhibition of TPA-caused induction of epidermal interleukin 1alpha (IL-1alpha) protein (39-72% inhibition, P < 0.005 or 0.001) and mRNA expression. Taken together, the results from these biochemical and molecular studies further substantiate our recent observation of silymarin's anti-tumor-promoting effects primarily at stage I tumor promotion. Furthermore, the observed inhibitory effects of silymarin on COX-2 and IL-1alpha should be further explored to develop preventive strategies against those cancers in which these molecular targets play one of the causative roles, such as non-melanoma skin, colon, and breast cancers in humans.

Incidence of aflatoxin producing strains and aflatoxin contamination in dry fruit slices of quinces (Cydonia oblonga Mill.) from the Indian state of Jammu and Kashmir

An investigation was undertaken to obtain data on the occurrence of aflatoxins and the aflatoxin producing potential of Aspergillus flavus strains isolated from dry fruit slices of quinces produced in jammu and Kashmir, India. A total of 147 A. flavus isolates recovered from dr fruit slices were grown in liquid rice flour medium and screened for the production of various aflatoxins by thin layer chromatography. The results showed that 23.14% of the tested isolates were aflatoxigenic, producing aflatoxins B1 and B2 in varying amounts. Aflatoxins G1 and G2 were not detected. All 25 of the investigated market samples were also found to be aflatoxin B1 positive and the level of contamination ranged from 96 to 8164 micrograms/kg of the dry fruit which is quite high in comparison to the permissible level of 30 ppb. As per these results biochemical composition of dry fruit slices of quinces, along with climatic conditions seem to be very favourable for aflatoxin production by the toxigenic A. flavus strains. Therefore, monitoring of aflatoxins in dry fruit slices of quinces is recommended for this region.

A p53-dependent S-phase checkpoint helps to protect cells from DNA damage in response to starvation for pyrimidine nucleotides

Normal mammalian cells arrest primarily in G1 in response to N-(phosphonacetyl)-L-aspartate (PALA), which starves them for pyrimidine nucleotides, and do not generate or tolerate amplification of the CAD gene, which confers resistance to PALA. Loss of p53, accompanied by loss of G1 arrest, permits CAD gene amplification and the consequent formation of PALA-resistant colonies. We have found rat and human cell lines that retain wild-type p53 but have lost the ability to arrest in G1 in response to PALA. However, these cells still fail to give PALA-resistant colonies and are protected from DNA damage through the operation of a second checkpoint that arrests them reversibly within S-phase. This S-phase arrest, unmasked in the absence of the G1 checkpoint, is dependent on p53 and independent of p21/waf1.

Modified helix-loop-helix motifs of calmodulin--The influence of the exchange of helical regions on calcium-binding affinity

The four calcium-binding sites, called the helix-loop-helix, or the EF-hand motifs, of calmodulin differ in their ion-binding affinities; this has been thought to arise due to the variations in the sequences of the loop regions where the ion binds. We focus attention here on the role of the flanking helical regions on the calcium-binding affinities. Peptides were synthesized in a manner that simulates the E and F helical flanks of site 4 (the strongest calcium-binding site of the calmodulin) to sandwich the loop sequences of sites 1, 2, 3 and 4 so as to produce peptides named 414, 424, 434 and 444, as well as using the helical flanks of site 1 (the weakest site) to produce peptides 111, 121, 131 and 141. Calcium binding was monitored using the calcium-mimic dye Stains-all (4,4,4',5'-dibenzo-3,3'-diethyl-9-methyl-thiacarbocyanine bromide). Binding abilities were seen to increase several-fold when the E and F helices of site 1 were replaced by those of site 4 (i.e., 111-414). In contrast, the intensity of circular dichroism induced in the absorption bands of the bound achiral dye decreased significantly when the helical flanks of site 4 were replaced with those of site 1 (i.e., 444-141). The helical flanks of site 4 impart greater binding ability to a given loop region, while the helical flanks of site 1 tend to weaken it.

A conformational study of corneal dermatan sulfate proteoglycan using fluorescence spectroscopy

DSPG is a major proteoglycan of the corneal stroma and is thought to be important for the transparency of the tissue. We have studied its conformation by exploring the microenvironment and dynamics of its lone Tryptophan (Trp) residue using steady state and time resolved fluorescence spectroscopy. DSPG exhibits a doublet Trp fluorescence emission. Such a doublet emission has been observed earlier in the copper protein azurin and in avian lens delta-crystallin. Unlike the above cases where the doublet emission is thought to arise due to vibronic structure or the location of Trp at the interface of interacting subunits, fluorescence quenching, denaturation studies and ANS binding with DSPG indicate the location of Trp at two different environments. Such a situation could arise from the differential glycosylation of the core protein or due to duplexation and aggregation of the glycosaminoglycan chains.

Effect of UVB radiation on corneal aldehyde dehydrogenase

PURPOSE

A Class 3 aldehyde dehydrogenase happens to be a major soluble protein constituent of the cornea. Its role is conjectured to be manifold: to protect the tissue from oxidative damage by eliminating the toxic aldehydes produced upon lipid peroxidation under oxidative stress, to act as an UV-absorber, and to maintain the level of the coenzyme NADH in the cornea. We have studied the effect of UVB on the structure and enzyme activity of corneal aldehyde dehydrogenase.

METHODS

Aldehyde dehydrogenase was irradiated at 295 nm for varying periods of time and change in its enzyme activity assayed. The structural changes in the molecule accompanying irradiation were monitored using fluorescence and circular dichroism spectroscopy, and its hydrodynamic behavior and surface hydrophobicity studied using gel filtration chromatography and binding of the hydrophobic fluorophore ANS. The protective ability of aldehyde dehydrogenase in preventing aggregation of photolabile proteins, such as Gamma-crystallin of the eye lens, was studied by monitoring the scattering value of the test protein with irradiation by UVB.

RESULTS

Aldehyde dehydrogenase is seen to undergo photodamage with alterations in its quaternary structure, though no significant change is noticed in the peptide chain conformation. Under such conditions the molecule continues to act as a protectant by preventing aggregation of photolabile proteins such as the eye lens Gamma-crystallin.

CONCLUSIONS

Our earlier studies have shown that the free sulfhydryl groups are important for the antioxidant abilities of aldehyde dehydrogenase. Its protective ability towards photoaggregation of Gamma-crystallin seen here might arise both due to: (i) oxyradical quenching and (ii) the increased surface hydrophobicity of the molecule upon irradiation, which allows it to bind to, and thus inhibit the aggregation of interacting proteins.

Conformation, stability and interactions of corneal keratan sulfate proteoglycan

We have monitored the molecular conformation, stability, interaction and dynamics of keratan sulfate proteoglycan, the major structural protein component of the cornea, in solution, by studying the fluorescence spectral features of its tryptophan residues as component-specific intrinsic spectral probes (collagen, the other structural component of the cornea, has no tryptophans). Our study suggests that the Trp region of the molecule is in a motionally restricted environment as it exhibits a fluorescence red-edge effect and shows dipole relaxation. The extrinsic spectral probe 8-anilinonaphthalene 1-sulfonate reveals keratan sulfate proteoglycan to possess significant surface hydrophobicity. This dual character of keratan sulfate proteoglycan allows us to label it as an 'ambidextran' proteoglycan. The molecule is stable between pH 5-8 and has a Tm value of 72 degrees C. Disulfide bonds play a role in the stability of the molecule. KSPG is seen to interact with collagen and the model compound, poly(L-proline). Interaction of the proteoglycan with unilamellar vesicles appears to be more interfacial than penetrative. This dual interaction displayed by KSPG with collagen and with lipid assemblages suggests that it plays the role of a 'filler' in the extracellular matrix of the cornea.

Fluorescence properties of isolated intact normal human corneas

We have examined the fluorescence properties of excised intact normal human corneas from over a hundred donors, using synchronous excitation fluorescence spectroscopy. In some of the corneas from the donors, a fluorophore with an excitation band centered at 330 nm was observed. This fluorophore does not seem to correspond to the dityrosine moiety or to any photoproducts of tryptophan. Isolated corneas irradiated with light of 295 nm wavelength do not produce any fluorescent photoproducts, suggesting that the intact tissue has endogenous quenchers, radical scavengers and antioxidants that inhibit its photodamage. The non-tryptophan fluorophores that accumulate in some corneas thus appear to arise largely from the nonenzymatic glycosylation (glycation) of the constituent proteins as similar fluorophores are detected in the corneas of rats in which diabetes is induced.

Calcium binding properties of beta-crystallins

beta-Crystallins, the oligomeric proteins of the eye lens, were found to bind calcium ions with low affinity, in the millimolar range. Calcium was found to induce conformational changes in the secondary and tertiary structure of beta-crystallins. While these changes in conformation are seen in low ionic strength media, they are masked when the protein is dissolved in an intermediate ionic strength medium, where oligomers of lower molecular weight are formed. The calcium binding takes place in these conditions. The behaviour of this protein with respect to calcium binding is reviewed.

Absenteeism among group-D employers

A study of absenteeism and man days lost in one hundred employees belonging to group "D" in a hospital at Jammu was conducted to explore the magnitude of problem of absenteeism and its remedy was sought. The study included the study of staffing pattern of the hospital, total group "D" employees, their jobs and work load and their attitudes, commencing from Sept. 1992 to Aug. 1995. Information regarding man days lost and man days schedule to work as records available in the hospital was used to calculate the trend, variations and fluctuations in absenteeism. For the purpose of calculations of absenteeism, nature of absence was divided into various headings like casual leave, sick leave, earned leave etc. A questionnaire was prepared and given to each employee and a detailed insight was sought with respect to his personality, social factors like accommodation, religious ceremonies, individual habits like drinking, gambling, job dissatisfaction and finally from the whole data absence rate, frequency rate and severity rate were calculated. From the observations it was concluded that absenteeism was more in females, in the age group of 33-45 years, married, in the months of Sept. to Nov. on Mondays and Saturdays and in Hindu backward classes. Though it seemed unreliable but all the employee opined that they were in harmony with their bosses and seemed satisfied with their jobs.

In situ fluorescence spectroscopic studies on bovine cornea

The cornea is a transparent ocular tissue and its transparency is thought to be a result of intramolecular interactions and the supramolecular organization of its protein constituents. We have studied the intrinsic fluorescence properties of intact bovine corneas and compared these with that of the opaque sclera. It was observed that with increasing excitation wavelengths the emission maxima shifted toward the red edge exhibiting the phenomenon of red edge excitation shift, which is indicative of immobilization of the constituent fluorophores. The magnitude of the shift increased after photodamage by irradiation at 295 nm. Many of the spectral characteristics of the cornea are shown to be due to its proteoglycans, which show surprisingly significant red edge excitation shift in solution.

Studies on the interaction of the dye, stains-all, with individual calcium-binding domains of calmodulin

We show that the calcium-mimic dye, Stains-all, is a convenient probe to study the structural features of the individual calcium-binding sites of calmodulin (CaM) and related calcium-binding proteins (CaBP). These peptides bind the dye in their calcium-binding sites, and induce a circular dichroism (CD) band in the bound dye in the 620 nm (J band) region, which is abolished upon the addition of calcium. Replacement of Asp by Asn in the + x position of the weaker calcium-binding site (site I of CaM) abolishes the dye binding, while the same change in the higher affinity site IV attenuates the binding of the dye and does not abolish it. Replacement of Tyr in site IV with Trp does not distort the geometry, although it increases the dye binding affinity.

Alteration of dynamic quaternary structure and calcium-binding ability of beta-crystallin by light

beta-crystallin, one of the three main constituent proteins of the eye lens, exists as an equilibrium population of oligomeric (beta H), trimeric (beta L1) and dimeric (beta L2) species. This equilibrium is dependent on various factors such as the protein concentration, ionic strength and pH of the medium. We have studied the effect of ultraviolet B radiation on the aggregational patterns of beta-crystallin, using size-exclusion chromatography. Irradiation of a solution of beta H-crystallin at 295 nm for about 30 min causes the deaggregation of the hexameric population into dimers. Irradiation for a longer time, however, produces cross-linked high molecular weight products. Irradiation of a beta L2 solution for 30 min does not perturb the elution profile, while irradiation for a longer time increases the content of beta L1 (trimeric) crystallin. Irradiation also causes a decrease in the calcium-binding affinity of the beta-crystallins.

A critical review of prescriptions in internal medicine

A study was undertaken to assess the prescribing trends in inpatients of the Internal Medicine Department of Government General Hospital which is attached to Guntur Medical College, Guntur. Prescriptions for 250 patients were audited under various heads like details of drugs used, generic versus trade name prescribing, dosage, dosage form, dose interval, drug of choice and duration of treatment. Among 250 prescriptions audited, 7 percent used generic names, 22 percent trade names, and 71 percent combinations of both generic and trade names. Dosages and dosage intervals were appropriate. In 75 percent of the audited cases, the duration of treatment was appropriate; 25 percent did not specify the duration. The choice of drugs was proper in 84 percent and inappropriate in 16 percent of cases. Certain deficiencies in the prescribing trends are analysed.

Conformation of alginate and pectate chains monitored by the binding of the dye stains-all

The carbocyanine dye Stains-all displays spectral colour shifts or metachromasia upon binding to proteins, polysaccharides and other anionic substrates. The conformational status of the binding region of the substrate appears to govern the metachromatic features of the bound Stains-all. We have used this property to derive information about the conformational differences between the two anionic polysaccharides alginate and pectate. The stronger induction of circular dichroism in the 500 nm region of the dye by pectate is indicative of a greater extent of helical order in this polymer in solution than in the alginate or perhaps even hyaluronate chains.

Monitoring ovarian cyclicity in postpartum Murrah buffalo through milk progesterone enzyme immunoassay

Milk samples were collected from Murrah buffalo between Day 30 and Day 120 post partum and analysed for progesterone concentration to monitor ovarian cyclicity. Progesterone levels were low (1 to 5 ng/ml) during the anestrous period. Levels were also low around estrus, but they began to increase at Day 6 postestrus; high levels (15 to 32 ng/ml) were maintained for different periods. There was a marked drop in progesterone level after Day 16 to 18 of the estrous cycle in those animals which returned to estrus. Progesterone levels remained high in buffalo which did not return to estrus, indicating that these animals were pregnant. Some of the progesterone cycles were not associated with the expression of estrus. This study indicated that a milk progesterone enzymoimmunoassay can be used to detect early pregnancy as well as conditions such as silent estrus and anovulatory estrus; it can thus help reduce the long intercalving period in buffalo.

Binding site conformation dictates the color of the dye stains-all. A study of the binding of this dye to the eye lens proteins crystallins

The interaction of the cationic carbocyanine dye Stains-all (1-ethyl-2-[3-(1-ethyl-naphthol[1,2-d]thiazolin-2-ylidene)-2- methylpropenyl]naphthol[1,2-d]thiazolium bromide) with the eye lens proteins crystallins has been studied. alpha- and gamma-crystallins do not bind the dye, while beta- and delta-crystallins do, consistent with the fact that the latter two proteins bind the calcium ion. beta-Crystallin resembles parvalbumin in that it induces only the J-band of the bound dye. delta-crystallin, on the other hand, induces only the gamma-band. Analysis of the metachromasia induced in the dye by these and other proteins suggests that Stains-all is responsive to the conformational status of the region to which it binds in a protein. The J-band of the dye is activated when it binds to a globular domain, and the gamma-band is activated when it binds to a helical stretch of the protein.

Calcium ion binding to delta- and to beta-crystallins. The presence of the "EF-hand" motif in delta-crystallin that aids in calcium ion binding

Abnormal levels of endogenous calcium ions are known to induce eye lens opacity, and a variety of causative factors has been proposed, including calcium-mediated aggregation and precipitation of the lens proteins crystallins. We have specifically looked in some detail at the interaction of Ca2+ with various crystallins and its consequences. Lenses incubated in solutions containing 10 mM Ca2+ or 5 mM Tb3+ opacified. Fluorescence titration of crystallins with TbCl3 revealed that this ion binds to delta- and beta-crystallins in solution. Equilibrium dialysis showed that four Ca2+ ions bind to one delta-crystallin tetramer with an affinity of 4.3 x 10(3) M-1. Analysis of the amino acid sequence of delta-crystallin reveals the presence of a calmodulin-type "helix-loop-helix" or "EF-hand" calcium ion binding conformational motif in the region comprising residues 300-350. This is a novel feature of the molecule not reported so far. No other crystallins appear to have this motif. beta-Crystallin also binds four Ca2+ ions/aggregate unit of mass 160 kDa, with an affinity of 2.6 x 10(3) M-1, presumably in the midregion of the molecule that is rich in anionic and polar residues. Circular dichroism spectroscopy shows that the binding of calcium ion leads to subtle conformational changes in the molecules, notably in the tertiary structure.

Assessment of observer variability in the classification of human cataracts

An in vitro cataract classification system was developed in our laboratories and used to demonstrate a relationship between sustained aspirin intake and the apparent deceleration or retardation of human cataract formation. The purpose of this investigation was to assess the reliability of this cataract classification schema. Sets of extracted human cataractous lenses, which had been photographed in vitro, were randomly assigned to five observers. The task was to classify the lenses on the basis of nuclear and cortical involvement, as reflected in color and area changes along five groupings. Assessments were made on the basis of both intraobserver and interobserver agreement levels, corrected for chance (weighted kappa values). All five examiners evidenced levels of intraobserver agreement which ranged between "Good" and "Fair" and "Excellent" (.46-.83). Each of the five observers was ranked on the basis of his agreement levels with the remaining four observers. The results followed a predictable pattern such that the more experienced the observer in classifying cataracts, the more consistent his rankings vis-à-vis the remaining four evaluators. These results are discussed in the general context of observer variability studies in the field of medicine.