Role of caspases in human renal proximal tubular epithelial cell apoptosis

In the present study, we have used an in vitro model of apoptosis using primary human renal proximal tubular epithelial (RPTE) cells to investigate the mechanisms involved in renal cell apoptosis. Treatment of RPTE cells with okadaic acid for 24-48 h induced apoptosis in a concentration-dependent manner. Apoptosis was accompanied by the activation of the p38 mitogen-activated protein kinase (MAPK) pathway followed by the activation of caspase-9, -3, and -7. The induction of caspase activity correlated with the proteolytic cleavage of beta-catenin, suggesting that beta-catenin is a caspase substrate. The caspase inhibitor, Z-Val-Ala-Asp-fluoromethylketone (Z-VAD-fmk), resulted in a dose-dependent inhibition of apoptosis and beta-catenin cleavage. These data suggest that okadaic acid-induced apoptosis is p38 MAPK and caspase-dependent and that proteolytic cleavage of beta-catenin by caspases is likely to be a downstream molecular event associated with the morphological and cytoskeletal changes induced during apoptosis.

Universal scaling laws of diffusion in a binary fluid mixture

A new universal scaling law relating the self-diffusivities of a binary fluid mixture and the excess entropies of its components is derived using mode coupling theory, reproducing the empirical scaling laws of Dzugutov [Nature (London) 381, 137 (1996)] and Hoyt et al. [Phys. Rev. Lett. 85, 594 (2000)] as special cases. The derived scaling laws are tested through numerical calculations for binary Lennard-Jones fluid mixtures for a wide range of physical parameters, and a very good correlation is observed. We have also arrived at a new universal scaling relationship between the cross-diffusivity and entropy for the first time.

Hypericin and hypocrellin induced apoptosis in human mucosal carcinoma cells

Potent photosensitizers hypocrellin A (HA), hypocrellin B (HB) and hypericin (HY) are lipid-soluble perylquinone derivatives of the genus Hypericum and have a strong photodynamic effect on tumors and viruses. However, the mechanisms of tumor cell death induced by HA, HB and HY are still unclear. Moreover, no reports have mentioned cell apoptosis induced by HA, HB and HY in human nasopharyngeal carcinoma (NPC) and other mucosal cells. In this study, we attempt to clarify the photodynamic effects of HA, HB and HY compounds in poorly differentiated (CNE2) and moderately differentiated (TW0-1) human NPC cells as well as human mucosal colon and bladder cells. Using these cell lines we investigated few hallmarks of apoptotic commitments in a drug dose dependent manner. Tumor cells photo-activated with HA, HB and HY showed cell size shrinkage and an increase in the sub-diploid DNA content. A loss of membrane phospholipid asymmetry associated with apoptosis was induced by all tumor cell lines as evidenced by the externalization of phosphatidylserine. Under apoptotic conditions, Western blot analysis of poly(ADP-ribose) polymerase, a caspases substrate, showed the classical cleavage pattern (116 to 85 kDa) associated with apoptosis in HA, HB and HY-treated cell lysates. In addition, 85 kDa cleaved product was blocked by the tetrapepdide caspase inhibitors such as DEVD-CHO or z-VAD-fmk. Both inhibitors protect tumor cells from apoptosis. These results demonstrate that tumor cell death induced by HA, HB and HY is mediated by caspase proteases. This study also identifies HB as a more potent and promising photosensitizer for the treatment of mucosal cancer cells.

Induction of apoptosis by Hypericin through activation of caspase-3 in human carcinoma cells

Potent photosensitizer Hypericin (HY), is a lipid soluble perylquinone derivative of the genus Hypericum and has a strong photodynamic effect on tumors and viruses. However, the mechanisms of tumor cell death induced by this compound is still unclear. Furthermore, there are no reports on mechanisms in cell apoptosis induced by perylquinones in human nasopharyngeal carcinoma (NPC) and other mucosal cells. We studied the photodynamic effects of HY compound in poorly differentiated (CNE2) and moderately differentiated (TW0-1) human NPC cells as well as human mucosal colon (CCL-220.1) and bladder (SD) cells. Using these cell lines we investigated few hall marks of apoptotic commitments in a drug and light dose dependent manner. Tumor cells photoactivated with HY showed cell size shrinkage and an increase in the sub-diploid DNA content. A loss of membrane phospholipid asymmetry associated with apoptosis was induced in all tumor cell lines as evidenced by the externalization of phosphatidylserine. Under apoptotic conditions, Western blot analysis of poly (ADP-ribose) polymerase, a caspase substrate, showed the classical cleavage pattern (116-85 kDa) associated with apoptosis in PDT-treated cell lysates. In addition, 85 kDa cleaved product was blocked by using tetrapeptide caspase inhibitors such as DEVD-CHO or z-VAD-fmk. These results demonstrate that tumor cell death induced by photoactivated HY is mediated by caspase proteases. This study also identifies that CNE2, CCL-220.1 (colon) and SD (bladder) cell lines are more sensitive than TW0-1 cell line to PDT using perylquinone HY.

Photodynamic-induced apoptosis of human nasopharyngeal carcinoma cells using Hypocrellins

It has been reported that novel photosensitizers Hypocrellin A and B, lipid soluble perylquinone derivatives of the genus Hypericum have a strong photodynamic effect on tumors and viruses. The molecular mechanisms of tumor cell death induction by Hypocrellin A and B are poorly understood. In this study, we have examined the photodynamic effects of Hypocrellin A and B compounds in poorly differentiated (CNE2) and moderately differentiated (TW0-1) human nasopharyngeal carcinoma (NPC) cells. Using these cell lines we investigated the role of the apoptotic pathway in photosensitized Hypocrellin A and B-mediated cell death. Tumor cells photoactivated with Hypocrellin A and B showed cell size shrinkage and an increase in the sub-diploid DNA content. A loss of membrane phospholipid asymmetry associated with apoptosis was induced by both tumor cell lines as evidenced by the externalization of phosphatidylserine (PS). A dose-dependent increase in caspases-3 protease activity inhibitable by the tetrapeptide inhibitor DEVD-CHO was also observed in both cell lines. Western blot analysis of poly (ADP-ribose) polymerase, a caspase substrate, showed the classical cleavage pattern (116 to 85 kDa) associated with apoptosis in Hypocrellin A and B-treated cell lysates. In addition, caspase inhibition blocked the externalization of membrane PS, indicating that the loss of membrane phospholipid asymmetry is a downstream event of caspases activation. These results demonstrate that tumor cell death induced by Hypocrellin A and B is mediated by caspase proteases. In conclusion, this study identifies both Hypocrellins (A and B) as potent and promising photosensitizers for the treatment of NPC.

Safety and efficacy of bisphosphonates beyond 24 months in cancer patients

PURPOSE

Bisphosphonate therapy has decreased the risk of skeletal complications associated with osteolytic bone lesions in patients with breast cancer and multiple myeloma. The large prospective studies have used 21 to 24 months of treatment. We studied the safety and efficacy of bisphosphonates in a subset of patients who received therapy for more than 24 months.

PATIENTS AND METHODS

Patients who received bisphosphonates (pamidronate or zoledronic acid) were identified. Data on skeletal events and laboratory parameters were gathered by chart review.

RESULTS

We studied 22 patients who received intravenous pamidronate or zoledronic acid for a duration of 3.6 years (range, 2.2 to 6.0 years). Prolonged therapy was well tolerated. No significant calcium, phosphorus, electrolyte, or WBC count abnormalities were encountered. There was a clinically insignificant decrease in hemoglobin and platelet count and an increase in creatinine in these patients. The fracture rate beyond 2 years was no greater than during the first 2 years of treatment. There were no stress fractures of long bones with prolonged therapy.

CONCLUSION

Prolonged treatment with the potent bisphosphonates pamidronate and zoledronic acid seems to be well tolerated and should be studied in prospective, randomized studies to document prolonged skeletal efficacy.

Management of psoriasis vulgaris with methotrexate 0.25% in a hydrophilic gel: a placebo-controlled, double-blind study

BACKGROUND

Methotrexate has been used as one of the first and systemic therapies for psoriasis. In general, 70% of patients with psoriasis prefer topical therapy as the treatment of choice.

OBJECTIVE

The purpose of this placebo-controlled double-blind study was to evaluate the clinical efficacy and tolerability of methotrexate 0.25% incorporated in a hydrophilic gel (hydroxyethylcellulose 1%) to treat patients afflicted with psoriasis vulgaris.

METHODS

Sixty patients (37M/23F) ranging between 18 and 70 years of age, with slight to moderate chronic plaque-type psoriasis and PASI (Psoriasis Area and Severity Index) scores between 5.3 and 17.5 joined the study. The mean duration of the disease at entry was 9.6 years (range 1-24 years). The diagnosis of psoriasis was established by clinical and histopathologic methods. Patients were sequentially randomized into two parallel groups. Each patient was allocated a precoded 100-g tube (active or placebo) with instructions on how to self-administer the trial medication topically (without occlusion) to their lesions two times daily for 5 consecutive days per week. The study lasted for 12 weeks with 4 weeks of active treatment. Patients were examined on a weekly basis and those showing total clearing or remission of lesions were considered effectively treated.

RESULTS

By the end of the treatment, breaking the code disclosed that methotrexate 0.25% gel had significantly treated more patients than placebo (83.3% vs. 6.7%; p < 0.0001), reduced the PASI score to a mean of 2.2, and cleared more plaques (82.2% vs. 4.3%; p < 0.0001). Laboratory evaluations, including CBC with differential and platelet count, renal function, liver chemistry [SGOT (aspartate transaminase) and SGPT (alanine transaminase)], and serum creatinine, were within the normal limits. The treatment was well-tolerated by all the patients, with no adverse drug-related symptoms and no dropouts. The study was followed up for 12 months from the first day of the treatment; two cured patients had relapsed after 8 months.

CONCLUSION

The findings of this study demonstrate that methotrexate 0.25% in a hydrophilic gel is well tolerated and significantly more effective than placebo as a patient-applied topical medication to treat psoriasis vulgaris.

Bone markers in the management of metastatic bone disease

Newer markers of bone formation and bone resorption are now available. Alone these new markers do not appear to be useful to diagnose metastatic bone disease. Several markers appear to be of prognostic importance and correlate with the extent of tumour in the skeleton. Serial monitoring of bone markers may be useful to monitor the efficacy of bisphosphonate and/or systemic therapy of both lytic and blastic bone metastases.

Experience of laparoscopic management in 100 patients with acute abdomen

BACKGROUND/AIMS

The decision to operate on a patient with acute abdominal pain comes to the mind of the surgeon if routine investigations fail to identify the cause. A negative laparotomy may have complications, while laparoscopy appears to be a valuable way to improve the accuracy of diagnosis of acute abdominal pain and offers a promising modality of treatment.

METHODOLOGY

The study included 100 patients with provisional diagnosis of acute abdomen after clinical examination and conventional diagnostic aids. All the patients have been subjected to diagnostic laparoscopy.

RESULTS

Eight cases (8%) were managed by laparotomy following diagnosis by laparoscope (disturbed ectopic pregnancy), while 92 cases (92%) were managed laparoscopically which resulted in 81 cases (81%) of successful laparoscopic procedure (31 appendectomies, 19 cholecystectomies, 12 ovarian cyst accident, and others) and 11 cases (11%) were converted to open surgery (4 gallbladder empyema, 2 appendicular mass, 2 intestinal obstruction, and others). Postoperative complications were two cases of wound infection managed conservatively (perforated appendix). The postoperative follow-up for six months was uneventful.

CONCLUSIONS

Laparoscopic management of acute abdomen is a safe and effective method with the advantages of small scar, short hospital stay and early recovery.

Early angiotensin converting enzyme inhibitor therapy after experimental myocardial infarction prevents left ventricular dilation by reducing infarct expansion: a possible mechanism of clinical benefits

OBJECTIVE

To examine the effects of early angiotensin-converting enzyme (ACE) inhibitor therapy after myocardial infarction on infarct expansion in an experimental rat model.

BACKGROUND

ACE inhibitor therapy within 24 h of acute myocardial infarction (AMI) reduces mortality by unknown mechanism(s).

METHODS

Rats underwent permanent coronary artery occlusion. A treated group received enalapril (1.9+/-0.2 mg/kg) daily in drinking water beginning 2 h after coronary artery occlusion, a time too late to reduce infarct size. Rats were sacrificed 2 days or 2 weeks after myocardial infarction. Hearts were arrested and fixed at a constant pressure, then sectioned and photographed for morphometric analysis.

RESULTS

Infarcts in the control group expanded between 2 days and 2 weeks after myocardial infarction (expansion index 0.7+/-0.1 versus 2.5+/-0.4, P< 0.05). However, infarct expansion remained unchanged in the enalapril group between 2 days and 2 weeks after myocardial infarction (expansion index 0.8+/-0.1 versus 1.3+/-0.1, NS). Two weeks after myocardial infarction, the enalapril group had fewer expanded infarcts than the control group (expansion index 1.3+/-0.1 versus 2.5+/-0.4, P< 0.05). While left ventricular volume increased in the control group between 2 days and 2 weeks after myocardial infarction (0.17+/-0.01 ml versus 0.36+/-0.03 ml, P< 0.05), it remained constant in the enalapril group (0.22+/-0.02 ml versus 0.25+/-0.03 ml, NS). Two weeks after myocardial infarction, the left ventricles were larger in the control group than in the enalapril group (0.36+/-0.03 ml versus 0.25+/-0.03 ml, P< 0.05).

CONCLUSIONS

Treatment with enalapril initiated 2 h after AMI prevented left ventricular dilation by limiting infarct expansion. This may explain the mechanism by which ACE inhibitor therapy started within 24 h of an AMI improves survival 5-6 weeks after infarction.

Diabetic foot ulcer--a prospective study

OBJECTIVE

To detect "Feet at Risk" early, its early diagnosis and treatment of foot ulceration to prevent amputation.

SETTING AND METHOD

One hundred patients with diabetic foot problems were seen at Baqai Institute of Diabetology and Endocrinology from 06-01-97 to 14-04-99. Each Patient was examined for peripheral pulses, sensations and reflexes, for dryness of skin, deformity, callus and nail disorders and were photographed on first visit.

RESULTS

There were 65% males and 35% females included in this study. Ninety nine patients were type II diabetics, 38% were either smokers or had other addictions (or were addicted to tobacco). Awareness about risk factors causing foot problems was lacking among all patients. Fifty percent patients were on oral hypoglycaemic agents, 48% were insulin treated, while 2% were on diet and exercise alone. Glycaemic control was poor in 70%, fair in 16% and was good in 14%, 31% were overweight and 5% patients were underweight. Duration of diabetes was greater than ten years in 58%, toes were affected in 44%, sole/metatarsal in 18%; rest included malleoli, heel etc. Eleven patients had ulcers on both feet. Neuropathic ulcer were 42%, neuro ischaemic 58%, Sixty nine percent patients were in the age group between 40-60 years. Cause unknown 29% blisters and boil 14%, trauma/cutting 17%, burns 8%, dry skin/callus 10%. Fundal changes were present in 37%; proteinuria in 37%, ischaemic heart disease in 20%, hypertension 18%, In 60% more than one antibiotic was used. Foot ulcers of fifty nine patients healed on conservative management, six patients had below knee amputation, fifteen had toe amputation; nine were still on treatment, eleven lost contact.

CONCLUSION

Lack of awareness, poor glycaemic control and duration of diabetes were the main factors causing diabetic foot problems. This study also confirmed that microvascular complications should be screened in patients with diabetic foot ulcers. Foot care education would be the most important way of dealing with this major problem.

Total synthesis of cryptophycin-24 (Arenastatin A) amenable to structural modifications in the C16 side chain

Two efficient protocols for the synthesis of tert-butyl (5S,6R,2E, 7E)-5-[(tert-butyldimethylsilyl)oxy]-6-methyl-8-phenyl-2, 7-octadienoate, a major component of the cryptophycins, are reported. The first utilized the Noyori reduction and Frater alkylation of methyl 5-benzyloxy-3-oxopentanoate to set two stereogenic centers, which became the C16 hydroxyl and C1' methyl of the cryptophycins. The second approach started from 3-p-methoxybenzyloxypropanal and a crotyl borane reagent derived from (-)-alpha-pinene to set both stereocenters in a single step and provided the dephenyl analogue, tert-butyl (5S,6R,2E)-5-[(tert-butyldimethylsilyl)oxy]-6-methyl-2, 7-octadienoate, in five steps. This compound was readily converted to the 8-phenyl compound via Heck coupling. The silanyloxy esters were efficiently deprotected and coupled to the C2-C10 amino acid fragment to provide desepoxyarenastatin A and its dephenyl analogue. The terminal olefin of the latter was further elaborated via Heck coupling. Epoxidation provided cryptophycin-24 (arenastatin A).

Pharmacological basis for the use of peach leaves in constipation

The aqueous crude extract (PPL.Cr) of peach leaves (Prunus persica) was studied for the possible presence of gut stimulatory constituent(s) to rationalize the folkloric use of the plant in constipation. PPL.Cr at the dose of 1-10 mg/ml caused a moderate degree of spasmogenic effect in isolated guinea-pig ileum. Pretreatment of the tissue with atropine (1 M) completely abolished the contractile effect of the plant extract similar to that of acetylcholine which is suggestive of a cholinergic mechanism. In isolated rabbit jejunum preparations, PPL.Cr produced a week spasmogenic effect followed by relaxation of the spontaneous contractions at higher doses. Bioassay-directed fractionation revealed that the spasmogenic activity was separated in the aqueous fraction, while the spasmolytic activity was concentrated in the ethyl acetate fraction. When tested against K(+)-induced contraction, both PPL.Cr and its ethyl acetate fraction (PPL.EtAc) caused a dose-dependent inhibition, suggesting calcium channel blockade (CCB). The presence of CCB in peach leaves was confirmed when pretreatment of the tissue with PPL.EtAc caused a dose-dependent rightward shift in the Ca(2+) dose-response curves, similar to that produced by verapamil. These data indicate that the plant contains spasmogenic (cholinomimetic) and spasmolytic (calcium antagonist) constituents, which are concentrated in the aqueous and ethyl acetate fractions, respectively. Furthermore, the laxative effect of the plant reported in the traditional system of medicine may be partially due to the cholinergic action, which was dominant over the spasmolytic component.

Treatment of external genital warts in men with imiquimod 2% in cream. A placebo-controlled, double-blind study

OBJECTIVE

The purpose of this double-blind, placebo-controlled study was to evaluate the safety, clinical efficacy and tolerability of imiquimod (2%) in cream to cure external genital warts in males.

METHODS

Preselected male patients (n=60) ranging between 18 and 50 years of age (mean 24.2) harbouring 558 lesions (mean 9.3) with clinical, histopathological and polymerase chain reaction (PCR) confirmed diagnosis of human papilloma virus (HPV) infection were randomized to two parallel groups. Each patient was allocated a precoded 25g tube, and instructions on how to apply the trial medication to their lesions at home once daily for three consecutive days per week (max. 12 application in 4 weeks). To evaluate the safety, clinical efficacy and tolerance, patients were exa-mined on a weekly basis. Cure was defined as the total elimination of treated warts with PCR, and Southern blot hybridization confirmed negative HPV DNA.

RESULTS

By the end of the treatment, 40% (24/60) patients and 49.8% (278/558) warts were cured. Breaking the code revealed that imiquimod cream had cured 70% (21/30) patients and 86.8% of warts, while placebo healed three subjects and 28 warts (P=0.0001). Eleven patients (18.3%), predominantly in the imiquimod cream group, experienced mild to moderate, non-objective, drug-related side effects with no dropouts. The study was followed up for 18 months from the first day of the treatment, and among the 26 cured patients, one in the imiquimod cream group and two in the placebo had a relapse after 14 months.

CONCLUSION

The study demonstrated that 2% imiquimod in cream with mild non-objective side effects is safe, tolerable and significantly more effective than placebo in curing external genital warts in males.

Vegetarian diet in the treatment of fibromyalgia

Brain tryptophan is low in fibromyalgia. Intake of protein rich in large neutral amino acids is reported to lower brain tryptophan. This study was undertaken to assess whether any reduction of such proteins by exclusion of animal protein from the diet reduced pain and morbidity in fibromyalgia patients. It was an open, randomized controlled trial. 37 subjects with fibromyalgia were enrolled in the vegetarian diet and 41 in the amitriptyline groups. The outcome was assessed with the help of frequencies of fatigue, insomnia & non-restorative sleep, pain score on a 10-point VAS and tender point count. Fatigue, insomnia and non-restorative sleep were present in 41, 26 and 32 subjects before and in 3, 0 and 0 subjects respectively at six weeks of treatment in the amitriptyline group. The pain score and tender point count were 6.2 +/- 1.9 & 16.1 +/- 2.3 before and 2.3 +/- 1.3 & 6.4 +/- 3.0 after treatment. All these differences were significant (P < 0.001). In the vegetarian diet group, fatigue, insomnia and non-restorative sleep were present in 36, 24 and 27 subjects before and in 34, 29 and 29 subjects at six weeks of treatment. The pain score and tender point count were 5.7 +/- 1.8 and 15.7 +/- 2.4 before and 5.0 +/- 1.8 & 14.7 +/- 3.6 after treatment. All these differences were insignificant except that in the pain score. The decrease in the pain score, though significant, was much smaller than that in the amitriptyline group. So, it may be concluded that vegetarian diet is a poor option in the treatment of fibromyalgia.

Management of intravaginal warts in women with 5-fluorouracil (1%) in vaginal hydrophilic gel: a placebo-controlled double-blind study

The purpose of this placebo-controlled, double-blind study was to determine the safety, tolerability and clinical efficacy of 5-fluorouracil (1%) in a vaginal hydrophilic gel (hydroxyethylcellulose, 1%) to cure intravaginal papillomas in women. Pre-selected, 60 women ranging between 18 and 50 years of age (mean 24.6), having 312 vaginal condylomas (mean 5.2) joined the study. The diagnosis of human papillomavirus (HPV) was established with clinical, histopathological and polymerase chain reaction (PCR) techniques. Subjects were randomized into 2 parallel groups. Each patient was allocated a pre-coded tube 15 g (active or placebo) with graduated vaginal applicators (disposable), and instructions how to insert 4 g of the trial medication deep into the vagina once at bedtime on every other day (1, 3 and 5) per week, to visit the clinic on day 7 for clinical evaluations and to receive the same pre-coded replacement to continue the regimen for another week. A maximum 12 applications were to be used in 4 weeks. Cure was defined as absence of clinical signs of infection, re-confirmed by PCR and Southern blot hybridization negative HPV DNA. By the end of the treatment 48.4% patients and 51.9% lesions were cured. Breaking the code revealed that 5-fluorouracil (1%) gel had cured 83.3% patients and 87% intravaginal warts. Placebo resolved 13.3% patients and 14% condylomas; (active gel versus placebo; P < 0.001). Twelve patients (20%) mostly in the active gel experienced mild erythema, erosion and oedema, with no drop-outs. Among cured patients 3 had a relapse after 16 months. In conclusion, the clinical results of the study demonstrate that 5-fluorouracil (1%) in a vaginal hydrophilic gel is safe, tolerable and significantly more effective than placebo to cure intravaginal warts in women.

Apoptosis in polycystic kidney disease: involvement of caspases

Polycystic kidney disease (PKD) is characterized by the development of large renal cysts and progressive loss of renal function. Although the cause of the development of renal cysts is unknown, recent evidence suggests that excessive apoptosis occurs in PKD. With the use of terminal deoxynucleotidyl transferase dUTP nick-end labeling staining, we have confirmed the presence of apoptotic bodies in cystic kidneys of congenital polycystic kidney (cpk) disease mice carrying a homozygous mutation at 3 wk of age. Apoptosis was localized primarily to the interstitium with little evidence of cell death in cyst epithelium or noncystic tubules. In addition, we observed that the expression of various caspases, bax and bcl-2, was upregulated in cystic kidneys. With the use of various substrates in enzyme activity assays, we have demonstrated a greater than sevenfold increase in caspase 4 activity and a sixfold increase in caspase 3 activity. These data suggest that there is a caspase-dependent apoptosis pathway associated with PKD and support the hypothesis that apoptotic cell death contributes to cyst formation in PKD.

Epithelin mRNA expression in polycystic kidney disease

Epithelins are polypeptides that are preferentially expressed in epithelial cells and modulate growth. Epithelin expression is predominant in tissues of epithelial origin such as the kidney, spleen, lung, placenta, and colon. Because polycystic kidney disease involves abnormal proliferation of the proximal and/or distal tubule epithelial cells, we investigated epithelin mRNA expression in polycystic kidneys of mice homozygous for the mutation. Epithelin mRNA was highly expressed in the polycystic kidneys of homozygous mice when compared with the heterozygotes or wild type controls. A study on the time course of epithelin expression indicated that epithelin mRNA expression paralleled cyst formation and progression of the disease. A 2-fold increase in expression was observed at Day 15, a stage when cystic changes were first visible. This increase in expression was also observed at Day 21, a stage of maximum disease pathology, which ultimately results in the death of the animal. In situ hybridization localized epithelin mRNA predominantly to the epithelial cell layer surrounding the cysts. The high levels of epithelin in epithelial cells suggest a role in renal epithelial cell proliferation and cyst formation in polycystic kidney disease.

Determinants of mortality among children in the urban slums of Dhaka city, Bangladesh

The growing slum population in the developing world is an increasing challenge for local health authorities. Little is known of the patterns of disease occurrence including treatment types offered in this population. The paper describes reported child mortality and its determinants, including the main diseases affecting children and treatments, in the slum population of Dhaka city, Bangladesh. 1500 households in three slum communities were included in a cross-sectional survey. Reported death rates in the households per 1000 children (0-107 months) within the last year from the interview were 20.5 for boys and 27.0 for girls. More girls than boys died in infancy (age < 12 months). The most frequent reported causes of deaths were tetanus in infancy and diarrhoea among children aged < or = 12 months. Vaccination coverage (DPT, polio, measles and BCG) was 73% for children < 3 years of age. The results showed that gender difference in mortality may have been influenced by the patterns of treatment received during sickness and the choice of treatment was determined by the financial ability of the households. Household income, children's vaccinations, TT immunization of mothers and personal cleanliness appeared to be significantly associated with child mortality. Despite the relatively high vaccination coverage for this population, child mortality remained alarmingly high, indicating that socioeconomic and environmental conditions must be improved to substantially reduce morbidity and mortality in this population.

Potent inhibition of influenza sialidase by a benzoic acid containing a 2-pyrrolidinone substituent

On the basis of the lead compound 4-(N-acetylamino)-3-guanidinobenzoic acid (BANA 113), which inhibits influenza A sialidase with a Ki of 2.5 microM, several novel aromatic inhibitors of influenza sialidases were designed. In this study the N-acetyl group of BANA 113 was replaced with a 2-pyrrolidinone ring, which was designed in part to offer opportunities for introduction of spatially directed side chains that could potentially interact with the 4-, 5-, and/or 6-subsites of sialidase. While the parent structure 1-(4-carboxy-2-guanidinophenyl)pyrrolidin-2-one (8) was only a modest inhibitor of sialidase, the introduction of a hydroxymethyl or bis(hydroxymethyl) substituent at the C5' position of the 2-pyrrolidinone ring resulted in inhibitors (9 and 12, respectively) with low micromolar activity. Crystal structures of these inhibitors in complex with sialidase demonstrated that the substituents at the 5'-position of the 2-pyrrolidinone ring interact in the 4- and/or 5-subsites of the enzyme. Replacement of the guanidine in 12 with a hydrophobic 3-pentylamino group resulted in a large enhancement in binding to produce an inhibitor (14) with an IC50 of about 50 nM against influenza A sialidase, although the inhibition of influenza B sialidase was 2000-fold less. This represents the first reported example of a simple, achiral benzoic acid with potent (low nanomolar) activity as an inhibitor of influenza sialidase.

Development of trans-2-[1H-imidazol-4-yl] cyclopropane derivatives as new high-affinity histamine H3 receptor ligands

Previously, a novel series of 1H-4-substituted imidazole compounds were described as potent and selective histamine (HA) H3 receptor ligands (Yates et al., 1999). The present studies extend the structure-activity relationships for optimal HA H3 receptor affinity and central nervous system penetration by incorporation of a conformationally restricted cyclopropane nucleus. Moreover, the current studies extend our understanding of ligand-receptor interactions at the HA H3 receptor with the development of high affinity HA H3 receptor antagonists containing a stereochemical presentation. Structure-activity relationships were established from in vitro HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cortical tissue homogenates. Systematic optimization of multiple structural features critical for HA H3 receptor affinity provided some of the most potent HA H3 receptor agents described. For example, GT-2331 was determined to bind to a single population of HA H3 receptors with a Ki of 0.125 nM. In vivo, GT-2331 has a favorable central nervous system penetration profile with an ED50 of 0.08 mg/kg (i.p.) in rats and a long duration of action (T1/2 > 4 h). In addition, GT-2331 was extremely selective for the HA H3 receptor versus other HA receptors and a battery of neurotransmitter, neuropeptide, hormone, or enzyme systems. Several compounds were tested in vitro which suggested HA H3 receptor heterogeneity and are discussed in terms of structure-activity relationships for the HA H3 receptor.

Identification and pharmacological characterization of a series of new 1H-4-substituted-imidazoyl histamine H3 receptor ligands

A new series of 1H-4-substituted imidazole compounds were synthesized and identified as potent and selective histamine (HA) H3 receptor ligands. These ligands establish that HA H3 antagonists exhibit stereoselective and conformational preferences in their binding to the HA H3 receptor. Structure-activity relationships were determined in vitro by HA H3 receptor-binding affinities using [3H]Nalpha-methylhistamine and rat cerebral cortical tissue homogenates. Several derivatives containing olefin, amide, and acetylene functional groups were identified as potent HA H3 receptor ligands. In the olefin series, GT-2227 (4-(6-cyclohexylhex-cis-3-enyl)imidazole) was identified as a potent HA H3 receptor ligand with a Ki of 4.2 +/- 0.6 nM, while the trans isomer (GT-2228) displayed a reduced potency (Ki = 15.2 +/- 2.4 nM). GT-2227 was also found to have excellent central nervous system penetration in an ex vivo binding paradigm (ED50 = 0.7 mg/kg i.p.). In the acetylene series, GT-2260 and GT-2286 both exhibited high affinity (Ki = 2.9 +/- 0.2 and 0.95 +/- 0.3 nM) and excellent central nervous system penetration profiles (ED50 = 0.43 and 0.48 mg/kg i.p., respectively). As a prototype for the series, GT-2227 showed high affinity for the human HA H3 receptor (3.2 nM) and minimal affinity for the human HA H1 (Ki = 13,407 +/- 540 nM) and H2 (Ki = 4,469 +/- 564 nM) receptor subtypes. GT-2227 also showed good selectivity for the HA H3 receptor over a broad spectrum of other neurotransmitter receptors (IC50 >/= 1 microM). Furthermore, GT-2227 improved acquisition in a cognitive paradigm without behavioral excitation or effect on spontaneous locomotor activity. In summary, the present studies demonstrate the development of novel HA H3-selective ligands, and lend support for the use of such agents in the treatment of disorders associated with cognitive or attentional deficits.