UROLITHIASIS IN AUSTRALIAN ABORIGINAL CHILDREN

Thirty-six Australian Aboriginal children with urolithiasis were reviewed. Males dominated the series. The age distribution ranged from 8 months to 12 years and nearly 70% were 2 years or younger. Thirty-five patients had upper tract stones. Ultrasound was diagnostic in 35 patients and was falsely negative in one. Dietary factors, dehydration and recurrent diarrhoea are incriminated in the aetiology, because ammonium urate and oxalate were the main constituents of the stones. Malformations of the urinary tract were rare and known metabolic disorders were not seen. Chemical dissolution of the stones was found to be a safe and effective adjuvant in the management of urate stones.     

Mediastinal teratoma in a neonate

A neonate with severe respiratory distress due to a benign mediastinal teratoma (MT) is reported. Despite early and easy surgical excision of the tumor, the child died due to poor cardiac function. Only ten cases of MT in neonates have been reported in the literature so far. While the tumor has been known to interfere with lung development in utero, postnatal myocardial dysfunction due to poor heart development has not been previously documented. Accepted: 22 September 1997     

Hepatoprotective Activity of Heptoplus on Isoniazid and Rifampicin Induced Liver Damage in Rats

The present study is designed to evaluate the efficacy of heptoplus a polyherbal formulation as an oral supplementary agent for isoniazid and rifampicin induced hepatotoxicity in rats. 50 and 100 mg/kg of heptoplus supplement were fed orally to the rats along with isoniazid and rifampicin and compared to rats treated with 100 mg/kg Liv 52 standard drug. Rats treated with isoniazid and rifampicin suffered from severe oxidative stress by the virtue of free radicals induced lipid per oxidation. As a result abnormal index of serum biochemical markers for liver function and increased liver lysosomal enzymes activity was observed. However rats nourished with 100 mg/kg of heptoplus and Liv 52 protected the liver from oxidative damage by maintaining normal antioxidant profile status and restored normal serum liver biochemical markers. Increased liver lysosomal enzymes activity is prevented in the rats supplemented with heptoplus and Liv 52. Histopathological analysis also revealed severe vascular changes and lobular necrosis in the treatment of isoniazid and rifampicin. Heptoplus (100 mg/kg) and Liv 52 supplemented rats liver apparently revealed normal architecture of liver. This study confirms that heptoplus has liver protective activity against Isoniazid and Rifampicin induced liver injury in rats, in par with Liv 52.     

Hypoxia-responsive polymeric nanoparticles for tumor-targeted drug delivery

Hypoxia is a condition found in various intractable diseases. Here, we report self-assembled nanoparticles which can selectively release the hydrophobic agents under hypoxic conditions. For the preparation of hypoxia-responsive nanoparticles (HR-NPs), a hydrophobically modified 2-nitroimidazole derivative was conjugated to the backbone of the carboxymethyl dextran (CM-Dex). Doxorubicin (DOX), a model drug, was effectively encapsulated into the HR-NPs. The HR-NPs released DOX in a sustained manner under the normoxic condition (physiological condition), whereas the drug release rate remarkably increased under the hypoxic condition. From in vitro cytotoxicity tests, it was found the DOX-loaded HR-NPs showed higher toxicity to hypoxic cells than to normoxic cells. Microscopic observation showed that the HR-NPs could effectively deliver DOX into SCC7 cells under hypoxic conditions. In vivo biodistribution study demonstrated that HR-NPs were selectively accumulated at the hypoxic tumor tissues. As consequence, drug-loaded HR-NPs exhibited high anti-tumor activity in vivo. Overall, the HR-NPs might have a potential as nanocarriers for drug delivery to treat hypoxia-associated diseases.     

STI571 (imatinib mesylate): the tale of a targeted therapy

STI571 (imatinib mesylate) is an example of the successful development of a targeted agent. Its target is the constitutively active tyrosine kinase (p210bcr-abl) in a hematologic neoplasm, chronic myelogenous leukemia (CML). The results in early clinical trials were remarkable and led to rapid approval by the Food and Drug Administration for clinical use of the STI571 in CML. This article reviews the pre-clinical and clinical development of this agent and also discusses some of the prevailing theories to explain the emerging problem of resistance. Future directions for this drug, possibly directed at other targets, are also discussed.     

Umbilical evagination of the bladder with omphalocele minor

A neonate with umbilical evagination of the bladder (UEB) and omphalocele minor (OM) is reported. The findings in this case support the origin of the urachus from the upper end of the cloaca rather than the allantois. The frequent occurrence of OM with urachal anomalies, including UEB, suggests an embryological association between the two conditions. Accepted: 18 November 1998     

A recombinant defective adenoviral agent expressing anti-bcl-2 ribozyme promotes apoptosis of bcl-2-expressing human prostate cancer cells.

Over-expression of bcl-2, a potent anti-apoptosis protein, is likely to be one of the genetic mechanisms through which human prostate cancer cells develop resistance to hormonal and other forms of therapy. To develop a therapeutic agent for hormone-resistant prostate cancer based on suppression of bcl-2 expression, we had previously designed and synthesized a dual-hammerhead ribozyme capable of recognizing and specifically cleaving human bcl-2 mRNA in vitro as well as in vivo. To increase the efficiency by which the anti-bcl-2 ribozyme can be delivered to target cells, we have created a recombinant replication-deficient (defective) adenoviral agent capable of expressing the anti-bcl-2 ribozyme upon infection. This viral agent effectively reduces intracellular levels of bcl-2 mRNA and protein in cultured LNCaP prostate cancer cells following standard infection procedures. Likewise, the defective adenovirus-anti-bcl-2 ribozyme induces extensive apoptosis in several androgen-sensitive (LNCaP) and androgen-insensitive (LNCaP/bcl-2 and PC-3) human prostate cancer cell lines that express differing amounts of bcl-2 protein. One androgen-insensitive prostate cancer cell line, DU-145, lacking in bcl-2 expression, was found to be completely refractory to the effects of the virus ribozyme, supporting the concept that the cytotoxic effects of the ribozyme are based solely on its effects on bcl-2 expression. Our results support further development of this adenovirus/anti-bcl-2 ribozyme for potential gene therapeutic purposes in certain forms of hormone-resistant prostate cancer where over-expression of bcl-2 proto-oncogene is indicated.     

Hypoxic pre-conditioning in a rat renal ischemia model: an evaluation of the use of hydralazine

Introduction  

With the advent of improved diagnostic and imaging techniques, it is now possible to detect renal cancers in their very early stages, when they are still present as small renal masses. In these situations, use of laparoscopic partial nephrectomy (LPN) techniques are indicated and have gained acceptance in major medical institutions worldwide, offering comparable oncological outcomes and improving quality of life in the patient when contrasted with open nephrectomy procedures. However, a complication that may occur during or after this surgery is the possibility of compromising renal function, as a result of extended ischemia times of more than 30 min. We have undertaken a systematic study of the potential of several agents that may enhance renal parenchymal preservation without causing unwanted renal dysfunction as a result of enhanced ischemia times. In this study, we have evaluated the potential of one such agent under study, namely hydralazine, which was shown earlier to enhance hypoxia inducible factor-1α (HIF-1α) levels in experimental animal systems. Our aim was to determine whether enhanced levels of HIF-1α via pre-treatment with hydralazine had a reno-protective effect after ischemic injury.