Emerging perspectives on glaucoma: highlights of a roundtable discussion

PURPOSE

To present emerging perspectives on open-angle glaucoma related to patient compliance, current drug therapy, and treatment options.

METHODS

Roundtable discussion.

RESULTS

The panel discussion identified the following issues about patient compliance:1. It is a common problem in clinical practice and is often underappreciated by physicians.2. It is difficult for clinicians to detect.3. There are several risk factors that increase the probability of noncompliance. 4. Compliance can be improved through education, communication, improvement of the doctor-patient relationship, compliance aids, and simplifying the treatment regimen.

CONCLUSION

Patients' compliance with the therapeutic regimen for open-angle glaucoma is very important to the eventual outcome of their disease treatment. Physicians can improve their patients' compliance by a few simple, cost-effective interventions in the clinical setting. When considering different agents as first-line therapies, once-a-day dosing would be optimal for enhancing compliance.

Effect of alcohol dependence on the levels of duodenal disaccharidases in human subjects

BACKGROUND

The aim of the study was to detect the duodenal enzyme activity in patients of alcohol dependence and to compare with non-alcoholic patients of non-ulcer dyspepsia.

METHODS

Disaccharidases (lactase, sucrase, maltase) were estimated in 20 non alcoholic patients of non-ulcer dyspepsia and 20 alcoholics admitted to the drug de-addiction and treatment centre of PGIMER, Chandigarh, India.

RESULTS

No significant influence of alcohol on enzyme levels in patients of alcohol dependence when compared to patients of non-ulcer dyspepsia was observed. However, a significant decrease in lactase level was noted in patients consuming more than 125 gm/day of alcohol.

CONCLUSION

Amount of consumption of alcohol showed decrease in lactase enzyme, but not in maltase and sucrase. There was no effect of duration of alcohol consumption on dissacharidases in the two groups.

Rotavirus infections

In 1976, John Rohde, highlighting the importance of diarrhea as prime killer of children in the developing world, beckoned the scientific community to "take science where the diarrhea is". The World Health Organization estimates that one billion diarrheal episodes occur in infants annually resulting in 3.3 million deaths, making diarrheal disease a major contributor to infant mortality in developing world (Bern et al., 1992). The need for simple, effective and inexpensive intervention to treat diarrhea and to prevent its occurrence is urgent and abundantly clear. Among the etiological agents of acute infectious diarrhea rotaviruses account for nearly 25% of hospital admissions in India with vomitting and diarrhea followed by severe dehydration in very young children below 2 years of age (Broor et al., 1985). In developing countries, it has been estimated that more than 870,000 children die from rotavirus infection every year (Perez-Schael, 1996). The discovery of rotavirus by Bishop and colleagues in 1973 initiated a line of research that has progressed rapidly towards the goal of prevention of rotavirus diarrhea (Bishop et al., 1973).

Immunohistochemical localization of transferrin in human breast cancer tissue

The present study was planned to detect the iron binding protein, transferrin (TR) in paraffin sections of the human breast tumors. The distribution of transferrin has been studied in 153 cases (63 benign lesions and 90 malignant tumors). The extent of staining reaction was determined by semiquantitative grading (weak, moderate and consistent). Positivity rate for transferrin was higher (92.2%) in malignant tumors as compared to benign breast lesions (28.5%) with significant p value (p = 0.0001) for both the groups. The intensity was variable in both the groups, being more intense in the malignant tumors. Tumors with higher grade of malignancy presented consistent positive staining along with the lymph nodes involved. The extent of immunoreactivity revealed a significant positive correlation with axillary lymph node status. However, no significant correlation was found with the age of the patients. Thus the study of transferrin in breast tumors besides being of prognostic significance helps in the further management of malignant lesions of the breast.

Effect of Giardia lamblia on duodenal disaccharidase levels in humans

The study was conducted to detect the effect of giardiasis on human disaccharidase levels. Forty patients attending the medical outpatient department of PGIMER, Chandigarh were enrolled. Twenty patients, positive for Giardia lamblia comprised the study group while 20 patients negative for Giardia lamblia were taken as controls. Upper gastrointestinal endoscopy was performed in all patients. Estimation of lactase, sucrase, maltase and trehalase was done in biopsies. Histopathological investigation was carried out in all biopsy specimens after Haematoxylin and Eosin staining. Complaints of pain abdomen and bloating occurred commonly in giardiasis. Four biopsy samples in study group showed mild increase in lymphomononuclear infiltrate. Giardia lamblia was detected in 7 biopsies. Lactase levels were decreased significantly (p < 0.05) in giardiasis. Rest of the enzymes were comparable to the controls. No differences in the enzyme activities were observed between males and females in either group and with the duration of symptoms.

Patient-oriented learning: a review of the role of the patient in the education of medical students

AIM

To explore the contribution patients can make to medical education from both theoretical and empirical perspectives, to describe a framework for reviewing and monitoring patient involvement in specific educational situations and to generate suggestions for further research.

METHODS

Literature review.

RESULTS

Direct contact with patients can be seen to play a crucial role in the development of clinical reasoning, communication skills, professional attitudes and empathy. It also motivates through promoting relevance and providing context. Few studies have explored this area, including effects on the patients themselves, although there are examples of good practice in promoting more active participation.

CONCLUSION

The Cambridge framework is a tool for evaluating the involvement of patients in the educational process, which could be used by curriculum planners and teachers to review and monitor the extent to which patients are actively involved. Areas for further research include looking at the 'added value' of using real, as opposed to simulated, patients; more work on outcomes for patients (other than satisfaction); the role of real patients in assessment; and the strengths and weaknesses of different models of patient involvement.

Inhibition of protein phosphatase 1 induces apoptosis in neonatal rat cardiac myocytes: role of adrenergic receptor stimulation

The mechanisms that regulate cardiac myocyte apoptosis are not well understood. To study the role of protein phosphatase 1 (PP1) and 2A (PP2A) in apoptosis, we exposed cultured neonatal rat cardiac myocytes to the phosphatase inhibitor okadaic acid (OA). Exposure (18 h) to 100 nM OA (a concentration which inhibits both PP1 and PP2A) decreased the number of adherent cells, caused genomic DNA fragmentation, and increased the percentage of apoptotic cells. These effects did not occur at a lower concentration of OA (1 nM) which is relatively specific for PP2A. Stimulation of alpha1- or beta-adrenergic receptors with norepinephrine (NE) in the presence of propranolol or prazosin partially blocked OA-induced apoptosis as measured by flow cytometry. Likewise, stimulation of adenylyl cyclase with forskolin reduced OA-induced apoptosis. Conversely, inhibition of protein kinase A with H89 or protein kinase C with chelerethrine potentiated OA-induced apoptosis. OA increased caspase-3 activity, and this effect was reduced by NE. Thus, inhibition of PP1 stimulates apoptosis in NRVM and stimulation of adrenergic receptors protects against OA-induced apoptosis.

Isoniazid- and rifampicin-induced oxidative hepatic injury--protection by N-acetylcysteine

The role of N-acetylcysteine (NAC), a glutathione (GSH) precursor, was investigated in protection against isoniazid- (INH) and rifampicin- (RIF) induced oxidative hepatic injury in young Wistar rats. The hepatotoxic dose of INH and RIF was 50 mg kg(-1) day(-1) each and the hepatoprotective dose of NAC was 100 mg kg(-1) day(-1). All drugs were administered intraperitoneally (i.p.) in sterile water (4.0 ml kg(-1) day(-1)) over a period of 3 weeks. Status of oxidative/antioxidative profiles was the mechanistic approach to assess the hepatotoxicity and/or hepatoprotection. The oxidative injury in INH-RIF co-exposed animals was closely associated with significant decline of GSH and related thiols, as well as with compromised antioxidant enzyme system. The oxidative stress was further supported by increased lipid peroxidation observed in these animals. The co-administration of NAC prevented the induction of oxidative stress in INH-RIF co-exposed animals. The amelioration of oxidative stress by NAC was faithfully reflected as normal morphology in these animals, except the presence of mild degree of portal triaditis in one animal co-exposed to INH-RIF and NAC. In contrast, the animals co-exposed to INH-RIF alone showed histological lesions which ranged from intralobular inflammation to patchy necrosis. These results suggest that INH-RIF-induced oxidative injury can be prevented by supporting the cellular antioxidant defense mechanism by NAC.

Epidemic dropsy--a clinical study of the Delhi outbreak

BACKGROUND

A major outbreak of epidemic dropsy occurred in Delhi, India, in August-September 1998, due to the consumption of contaminated mustard oil.

METHODS

The clinical data of 212 adult patients of epidemic dropsy who presented to our hospital is analysed.

RESULTS

Pitting pedal oedema (100%), skin erythema (75%), limb tenderness (63%), diarrhea (51%) and hepatomegaly (34%) were the prominent clinical manifestations observed in the patients. Superficial retinal haemorrhages and retinal venous dilatation was observed on fundus examination and 9% of patients developed an open angle glaucoma over a three month follow up period. Cardiac failure was present in 14% of patients. Most patients had mild disease which responded to cessation of mustard oil consumption, bed rest, diuretics and antioxidants. There were six deaths, all of whom had intractable cardiac failure. A unique feature of this outbreak was the documentation of acute renal failure in three patients, a phenomenon never described previously.

CONCLUSIONS

Strict law enforcement to prevent the contamination of edible oils is essential to avoid the occurrence of future similar outbreaks.

Role of Q190 of MuLV RT in ddNTP resistance and fidelity of DNA synthesis: a molecular model of interactions with substrates

Gln190 of MuLV reverse transcriptase (RT) plays an important role in the catalytic mechanism of MuLV RT for its conservative and non-conservative mutant derivatives exhibit low catalytic activity. We now report that both Q190N and Q190A MuLV RTs are more efficient in their activity to incorporate ddNTPs and exhibit higher fidelity than the wild-type (WT) enzyme of DNA synthesis in both RNA- and DNA-directed reactions. To obtain some insight into the structural basis for the differential utilization of dNTP and ddNTP by the mutant enzymes, we modeled the binary and the ternary complexes of MuLV RT using corresponding HIV-1 RT structures and available structure of the fragment of MuLV RT. Q190 of MuLV RT appears to be essential for the interaction with 3'OH of dNTP. The lack of a 3'OH moiety in ddNTP does not permit the binding of ddNTPs to WT MuLV RT. However, the shorter side chain of Q190N (or A) mutant MuLV RT and the absence of 3'OH in ddNTP result in the rearrangement of hydrophobic interactions favoring the binding and limited incorporation of ddNTPs. In addition, while modeling the binary and ternary complexes of MuLV RT, we noted that in the formation of the ternary complex, an interaction of Q190 with dNTP substrate requires a shift from its interaction with the template base. This may be achieved by a small conformational change or motion of the loop between beta9 and alphaH containing Q190, which may correspond to the conformational change step requiring participation of Q190 during the catalytic reaction as reported in an earlier biochemical investigation.

Diagnostic value of ileoscopy: a report from India

Our aim was to present a report about the usefulness of ileoscopy as an adjunct to colonoscopy, as studied in India, in the face of a dearth of such reports from the developing countries and to study the role of ileoscopy in increasing the yield of diagnosis reached and modified. In a prospective study in 66 consecutive patients undergoing colonoscopy for various indications, colonoscopy/ileoscopy was performed with a forward viewing fiberoptic colonoscope. Details of ileal mucosa, time taken to reach ileum, and length of ileum intubated were noted. Of the 66 patients undergoing colonoscopy, cecum could be reached in 62, whereas ileum was successfully intubated in 57 (86.4%). In 13 (22.5%) cases, additional information was obtained. In eight (14.4%) cases, diagnosis was established on ileoscopy. Of these, two were of lower gastrointestinal (GI) bleed (typhoid ulcer and nonsteroidal antiinflammatory drug ulcer), one had lymphoma, two had tuberculosis, and three were cases of reactive arthritis with ulcers in terminal ileum. After ileoscopy, the diagnosis was altered in five (8.7%) cases. Time taken to reach ileum from cecum was 3.3 +/- 2.5 minutes and the length of examined ileum was 17.3 +/- 7.5 cm. Ileoscopy is a useful adjunct to colonoscopy that not only helps to modify the diagnosis but also established them.

Preparation of the cervix for surgical termination of pregnancy in the first trimester

Worldwide, surgical vacuum aspiration is the method of choice of terminating first trimester unwanted pregnancy. Cervical priming prior to surgical evacuation reduces the risks of cervical injury by making the cervix softer and easier to dilate. Over the years, a number of effective methods of cervical priming have became available: osmotic dilators; antiprogesterone and prostaglandins. Of these, prostaglandins remain the most widely used method of cervical preparation. However many of the natural and synthetic analogues of prostaglandins are either expensive or associated with troublesome side-effects. More recently, misoprostol, a synthetic 15-deoxy-16 hydroxy 16-methyl analogue of naturally occurring prostaglandin E, used in the management of peptic ulcers, has established a lead for cervical priming in terms of availability, ease of administration, cost and effectiveness. In fact it appears that both oral and vaginal misoprostol given at dosages of 400 microg are effective for cervical priming when administered 3 h prior to surgical vacuum aspiration. Now that the use of misoprostol for cervical priming has been validated, its widespread use in gynaecological practice is expected.

Recruitment properties of intramuscular and nerve-trunk stimulating electrodes

Functionally useful reanimation of paralyzed limbs generally requires reliable, finely graded control of muscle recruitment and force with minimal fatigue. We used force and electromyographic (EMG) recordings in combination with myofibrillar adenosine triphosphatase activity and glycogen depletion analysis to investigate the recruitment properties of intramuscular (IM) and nerve cuff (NC) stimulating electrodes implanted acutely or chronically in cat hindlimbs. Overall, 32 muscles were submaximally stimulated with current intensities producing approximately 20% of maximal twitch force using 330 ms trains of pulses at 20 and 40 pps. Both the glycogen-depletion and fatigue-test results were found to be difficult to interpret because NC stimulation resulted in surprisingly unstable recruitment during such trains. Fluctuations of force and M-waves within trains of identical stimuli were significantly greater for NC than for IM stimulation. NC stimulation produced much steeper recruitment curves and a reduced tetanus/twitch ratio compared to IM stimulation. IM stimulation produced more reliable and less fatigable recruitment of a mix of motor unit types that tended to be localized in neuromuscular compartments containing, or adjacent to, the IM electrode. We hypothesize that trains of submaximal stimulation applied through NC electrodes resulted in fluctuating recruitment because this electrode configuration magnifies the effects of refractoriness and small changes in axonal excitability during pulse trains.

The J-helix of Escherichia coli DNA polymerase I (Klenow fragment) regulates polymerase and 3'- 5'-exonuclease functions

To assess the functional importance of the J-helix region of Escherichia coli DNA polymerase I, we performed site-directed mutagenesis of the following five residues: Asn-675, Gln-677, Asn-678, Ile-679, and Pro-680. Of these, the Q677A mutant is polymerase-defective with no change in its exonuclease activity. In contrast, the N678A mutant has unchanged polymerase activity but shows increased mismatch-directed exonuclease activity. Interestingly, mutation of Pro-680 has a Q677A-like effect on polymerase activity and an N678A-like effect on the exonuclease activity. Mutation of Pro-680 to Gly or Gln results in a 10-30-fold reduction in k(cat) on homo- and heteropolymeric template-primers, with no significant change in relative DNA binding affinity or K(m)((dNTP)). The mutants P680G and P680Q also showed a nearly complete loss in the processive mode of DNA synthesis. Since the side chain of proline is generally non-reactive, mutation of Pro-680 may be expected to alter the physical form of the J-helix itself. The biochemical properties of P680G/P680Q together with the structural observation that J-helix assumes helical or coiled secondary structure in the polymerase or exonuclease mode-bound DNA complexes suggest that the structural alteration in the J-helix region may be responsible for the controlled shuttling of DNA between the polymerase and the exonuclease sites.

Syntheses and biological evaluation of 3-substituted amino-1-aryl-6-hydroxy-hex-2-ene-1-ones as antioxidant and hypolipidemic agents

A new series of compounds belonging to 3-substituted amino-1-aryl-6-hydroxy-hex-2-ene-1-ones (4-12a-e) have been synthesized and evaluated for antioxidant and hypolipidemic activities. Amongst all the synthesized compounds, seven compounds, namely 5b, 5d, 6e, 8a, 8b, 10b and 11a, exhibit better antioxidant activity than probucol. Two compounds, 5d and 10b, have been evaluated in detail for antioxidant and hypolipidemic activities and show comparable activity profile to that of probucol and guggulipid. From the present study it may be postulated that the mechanism of action of these compounds could be through activation of lecithin cholesterol acyltransferase (LCAT), liver lipolytic activity, increased faecal bile acid secretion and inhibition of hepatic cholesterol biosynthesis.

Reversible portal hypertension due to tuberculosis

Presentation of abdominal tuberculosis with portal hypertension is rare. We report a 25-year-old man with portal hypertension due to compression of the portal vein by tuberculous lymph nodes at the hepatic hilum. After antitubercular therapy, features of portal hypertension disappeared as the nodes regressed.

A carboxylate triad is essential for the polymerase activity of Escherichia coli DNA polymerase I (Klenow fragment). Presence of two functional triads at the catalytic center

The catalytic roles of two essential active-site aspartates at positions 705 and 882 of Escherichia coli DNA polymerase I have been well established (Steitz, T. A. (1998) Nature 391, 231-232). We now demonstrate that the participation of at least one additional carboxylate, a glutamate at position 710 or 883, is obligatory for catalysis. This conclusion has been drawn from our investigation of the properties of single (E710D, E710A, E883D, and E883A) and double (E710D/E883D and E710A/E883A) substitutions of residues Glu(710) and Glu(883). While single substitutions of either of the glutamates resulted in some reduction in polymerase activity, the mutant enzyme with simultaneous substitution of both glutamates with alanine exhibited a nearly complete loss of activity. Interestingly, substitution with two aspartates in place of the glutamates resulted in an enzyme species that catalyzed DNA synthesis in a strictly distributive mode. Pyrophosphorolytic activity of the mutant enzymes reflected their polymerase activity profiles, with markedly reduced pyrophosphorolysis by the double mutant enzymes. Moreover, an evaluation of Mg(2+) and salt optima for all mutant enzymes of Glu(710) and Glu(883) revealed significant deviations from that for the wild type, implying a possible role of these glutamates in metal coordination as well as in maintaining the structural integrity of the active site.

p38 mitogen-activated protein kinase pathway protects adult rat ventricular myocytes against beta -adrenergic receptor-stimulated apoptosis. Evidence for Gi-dependent activation

We have shown that stimulation of beta-adrenergic receptors (beta-AR) by norepinephrine (NE) increases apoptosis in adult rat ventricular myocytes (ARVMs) via a cAMP-dependent mechanism that is antagonized by activation of G(i) protein. The family of mitogen-activated protein kinases (MAPKs) is involved in the regulation of cardiac myocyte growth and apoptosis. Here we show that beta-AR stimulation activates p38 kinase, c-jun N-terminal kinases (JNKs), and extracellular signal-regulated kinase (ERK1/2) in ARVMs. Inhibition of p38 kinase with SB-202190 (10 micrometer) potentiated beta-AR-stimulated apoptosis as measured by flow cytometry and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining. SB-202190 at this concentration specifically blocked beta-AR-stimulated activation of p38 kinase and its downstream substrate MAPK-activated protein kinase-2 (MAPKAPK2). Pertussis toxin, an inhibitor of G(i)/G(o) proteins, blocked the activation of p38 kinase and potentiated beta-AR-stimulated apoptosis. Activation of G(i) protein with the muscarinic receptor agonist carbachol protected against beta-AR-stimulated apoptosis. Carbachol also activated p38 kinase, and the protective effect of carbachol was abolished by SB-202190. PD-98059 (10 micrometer), an inhibitor of ERK1/2 pathway, blocked beta-AR-stimulated activation of ERK1/2 but had no effect on apoptosis. These data suggest that 1) beta-AR stimulation activates p38 kinase, JNKs, and ERK1/2; 2) activation of p38 kinase plays a protective role in beta-AR-stimulated apoptosis in cardiac myocytes; and 3) the protective effects of G(i) are mediated via the activation of p38 kinase.

Optical encryption by double-random phase encoding in the fractional Fourier domain

We propose an optical architecture that encodes a primary image to stationary white noise by using two statistically independent random phase codes. The encoding is done in the fractional Fourier domain. The optical distribution in any two planes of a quadratic phase system (QPS) are related by fractional Fourier transform of the appropriately scaled distribution in the two input planes. Thus a QPS offers a continuum of planes in which encoding can be done. The six parameters that characterize the QPS in addition to the random phase codes form the key to the encrypted image. The proposed method has an enhanced security value compared with earlier methods. Experimental results in support of the proposed idea are presented.

Comparison of seven and fourteen days of lansoprazole, clarithromycin, and amoxicillin therapy for eradication of Helicobacter pylori: a report from India

BACKGROUND

In developed countries, a 1-week regimen of combined proton pump inhibitors and two antibiotics is considered adequate for Helicobacter pylori eradication. However, there is a paucity of reports from developing countries on treatment duration of less than 14 days. We compared efficacy of 7 and 14 days of lansoprazole (L), clarithromycin (C), and amoxicillin (A) combinations for eradication of H. pylori.

PATIENTS AND METHODS

Forty-six consecutive patients who presented with upper gastrointestinal symptoms and tested positive for H. pylori infection were included in the study. In every patient, after performance of upper gastrointestinal endoscopy, antral biopsies were obtained. H. pylori infection was diagnosed by positive rapid urease test and identification of organisms on antral histology. Patients were randomly selected to receive lansoprazole, 30 mg once daily, plus clarithromycin, 250 mg twice daily, plus amoxicillin, 500 mg three times daily for 2 weeks (group 1; n = 24; age, 36 +/- 12 years; 18 men) or 1 week (group 2; n = 22; age, 45 +/- 15 years; 12 men). One month after completion of treatment, repeat upper gastrointestinal endoscopy was performed. H. pylori eradication was defined as absence of organism on histopathological examination of both antrum and body of stomach and negative rapid urease test.

RESULTS

Eradication rate was higher in group 1 (23 of 24; 96%) as compared to group 2 (12 of 22; 54%; p <.05). One patient in group 1 had diarrhea, and one patient in group two had skin rash and itching.

CONCLUSIONS

Fourteen-day therapy with lansoprazole, clarithromycin, and amoxicillin is highly effective in eradication of H. pylori. Reducing duration of therapy to 7 days significantly lowers eradication rates.