Some novel approaches for radioprotection and the beneficial effect of natural products.

Due to the increased use of ionizing radiation in various aspects of human life especially in areas pertaining to radiotherapy of cancer, food preservation, agriculture, industry and power generation, there is a need to develop an effective and non-toxic radioprotector. The currently available ones have many drawbacks including high cost, side effects and toxicity. Several novel approaches are on to locate a potent radioprotector. These include mimics of antioxidant enzymes, nitroxides, melatonin, growth factors, gene therapy, hyperthermia apart from natural products. The latter has several advantages since they are non-toxic with proven therapeutic benefits. These can be classified as natural compounds and plant extracts; polyherbal formulations; besides natural and semi-natural compounds of plant origin. A review of the above agents, their efficacy in radioprotection and possible mechanisms responsible has been carried out. As India and many Eastern countries have an enormous heritage of vast natural dietary and time tested medicinal resources it is worth exploring the possibility of developing efficient, economically viable and clinically acceptable radioprotectors for human application from these resources.

Is ultrasonography essential before surgery in eyes with advanced cataracts?

BACKGROUND: Ultrasonography is an important tool for evaluating the posterior segment in eyes with opaque media. AIM: To study the incidence of posterior segment pathology in eyes with advanced cataract and to see whether certain features could be used as predictors for an abnormal posterior segment on ultrasound. SETTING: Tertiary care hospital in South India. METHODS AND MATERIALS: In this prospective study conducted over a 6-month period, all eyes with dense cataracts precluding visualization of fundus underwent assessment with ultrasound. Presence of certain patient and ocular "risk" factors believed to be associated with a higher incidence of abnormal posterior segment on ultrasound were looked for and the odds ratio (OR) for posterior segment pathology in these eyes was calculated. RESULTS: Of the 418 eyes assessed, 36 eyes (8.6%) had evidence of posterior segment pathology on ultrasound. Retinal detachment (17 eyes; 4.1%) was the most frequent abnormality detected. Among patient features, diabetes mellitus (OR= 4.9, P= 0.003) and age below 50 years (OR= 15.4, P= 0.001) were associated with a high incidence of abnormal ultrasound scans. In ocular features, posterior synechiae (OR= 20.2, P= 0.000), iris coloboma (OR= 34.6, P= 0.000), inaccurate projection of rays (OR= 15.1, P= 0.002), elevated intraocular pressure (OR= 15.1, P= 0.004) and keratic precipitates (OR= 22.4, P= 0.004) were associated with high incidence of posterior segment pathology. Only four eyes (1.5%) without these features had abnormal posterior segment on ultrasonography. CONCLUSIONS: Certain patient and ocular features are indicative of a high risk for posterior segment pathology and such patients should be evaluated by ultrasonography prior to cataract surgery. In the absence of these risk factors, the likelihood of detecting abnormalities on preoperative ultrasonography in eyes with advanced cataracts is miniscule.

Severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is a form of atypical pneumonia that apparently originated in Guangdong Province of the People's Republic of China in late 2002. This first came to the world's attention in late February 2003, and has since spread worldwide. As of June 23rd 2003, the disease had been reported from 32 countries or regions globally, affecting 8459 people; 805 individuals (9.5 % of the total affected) have died of the disease. A novel coronavirus, the SARS-associated coronavirus (SARS- CoV) has been found in various specimens taken from patients with SARS. Although there has been rapid development of tests to detect SARS Co-V, these tests presently have certain limitations. Definitions of suspected, confirmed and probable cases have been formulated. Measures currently used for the management of patients with SARS include isolation, ribavirin, corticosteroid therapy and mechanical ventilation. Unfortunately, almost 10 % of affected patients succumb to their illness, underlying the need for developing more effective therapy. It remains to be seen how long it will take to bring this epidemic under control.

Biological significance of singlet oxygen.

The biological significance of singlet oxygen (1O2), an electronically excited species of oxygen, has been realized only in the last two decades. This was mainly due to the lack of proper methodology to generate this reactive oxygen species (ROS) in pure form and its reactions with biological molecules. Recent studies, using newly developed detection methods, show that 1O2 being generated in many biological systems, can significantly and quite often adversely alter several crucial biomolecules including DNA, proteins and lipids with undesirable consequences including cytotoxicity and/or disesase development. The reactions of 1O2 with the biological molecules are rather specific, as compared to other ROS. There are various compounds, mainly derived from natural sources that offer protection against damage induced by 1O2. Among the antioxidants carotenoids are the most effective singlet oxygen quenchers followed by tocopherols and others. The same reactive species if generated specifically in diseased states such as cancer can lead to the cure of the disease, and this principle is utilized in the newly developing modality of cancer treatment namely photodynamic therapy. Singlet oxygen, in low concentrations can also act as signaling molecule with several biological implications. This review clearly brings out the biological significance of 1O2.

Keratomycotic malignant glaucoma.

Malignant Glaucoma due to Keratomycosis is a devastating and poorly recognised complication occurring in a small percentage of treated patients. It is characterized, in cases of Keratomycosis by a raised tension, uniform shallowing of the anterior chamber and a fungus-exudate-iris mass covering the pupillary area. Three cases of 'Keratomycotic Malignant Glaucoma' are discussed here. Two of these were successfully treated with therapeutic keratoplasty, extracapsular lens extraction and systemic antifungals. The development of malignant glaucoma after a therapeutic keratoplasty which occurred in one case has not previously been reported. All the three cases which developed malignant glaucoma had a pupillary size of 4 mm diameter or less and grew Fusarium from the cornea and anterior chamber.

A simple method to quantitate circulating immune complexes in different diseases.

Immune Complexes are involved in the Pathogenesis of many diseases of varied aetiology such as autoimmune disorders, protozoal diseases, bacterial and viral infections. Quantitation of immune Complexes in these diseases can be used for diagnosis and to ascertain the prognosis. The simple method of precipitation by polyethylene glycol and quantitation by single Radial Immunodiffusion has been used in leprosy, syphilis, bacterial endocarditis and systemic lupus erythematosus (SLE). This method found significantly higher levels of circulating immune complexes (CICs) in erythema nodosum leprosum, culture positive bacterial endocarditis and SLE where CICs are known to play an important role in the pathogenesis.

Itraconazole therapy for fungal keratitis.

110 cases of keratomycosis were treated with itraconazole administered either orally or topically or by both routes. Excellent or moderate response was obtained in 69 percent of the patients. Ulcers due to Aspergillus and dematiaceous fungi and non-sevee ulcers responded better than did severe ulcers and ulcers due to Fusarium. A combination of oral and topical itraconazole yielded the highest percentage of excellent or moderate responses.