Mechanisms of Action of Drugs Which Alter Aqueous Humour Formation

There is a great need for an in vitro model for studying aqueous humour dynamics. A large number of antiglaucoma drugs is currently in clinical use or are in various stages of development, and in some cases their underlying biochemical mechanisms of action are unclear. The present work was undertaken to find out whether the easily obtainable inexpensive bovine eye could be established as such a model to study the physiology and pharmacology of ocular hypotensive drugs. The specific objective was to try to explore the mechanism of action of the extensively used beta-blocker, timolol, to determine whether it acts through the conventional beta-adrenoceptor-adenylate cyclase mechanism, as is often assumed. The isolated arterially perfused bovine eye has been proved to be a valid model for studying aqueous humour dynamics and the pharmacology of various antiglaucoma drugs. Its usefulness has been shown by significant effects of standard and well-established ocular hypotensive agents, such as timolol and MK-927, a carbonic anhydrase inhibitor, on both intraocular pressure and aqueous humour formation. MK-927 produced a dose-dependent decrease in intraocular pressure and aqueous humour formation with moderate doses of 1, 10 or 100 nmol. In addition to the responses to the standard drugs, the viability and metabolic activity of the isolated perfused eye has been shown by significant consumption of O[2] and elaboration of CO[2] during the course of perfusion. This was achieved by comparing the two parameters between the perfused living and dead eyes. The bovine perfused eye has been shown to offer the opportunity to study the effect of ocular hypotensive drugs upon intracellular mechanisms, especially upon second messenger pathways. It allows rapid and convenient sampling of substantial amounts of target tissue for biochemical analysis after drug challenge. The usefulness of the perfused eye has also been shown for isolating and culturing ciliary epithelial cells. Two new methods of isolating and culturing ciliary epithelial cells have been developed. One by aseptic and consecutive perfusion of the isolated eye with DMEM, calcium-free buffer and collagenase and the other by incubating the excised ciliary processes with collagenase. The cells were successfully propagated up to 10 passages without any obvious sign of change of growth characteristics. In first passage cells cultured in this way, there occurred highly significant and concentration-dependent increases in cyclic AMP and cyclic GMP in response to terbutaline and atriopeptin, respectively, indicating that these cells retain functional receptors. This will open up broad opportunities for physiological, pharmacological and biochemical studies on specific target cells responsible for aqueous humour production. (Abstract shortened by ProQuest.)

The sisterhood method of estimating maternal mortality : a study in Matlab, Bangladesh

The thesis is about ways to improve the technique of maternal mortality estimation known as the "sisterhood method', which entails questioning respondents on the circumstances of death for any sister who may have died. From the records of maternal deaths that occurred during 1976-90 in the Matlab Demographic Surveillance System (DSS) area, a field station of the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), a list was prepared of deceased women's surviving brothers and sisters, aged 15 years and over, born to the same mother. One adult brother or sister of each of the deceased women was interviewed and asked whether he or she had a sister whose death was due to pregnancy, childbirth or in the 90 days after childbirth. Information on maternity-related deaths obtained in the survey was then compared with the information recorded in the DSS. Results suggest that in places similar to Matlab the sisterhood method will produce negative bias in estimates of maternal mortality mainly through misreporting of induced abortion-related deaths, particularly those associated with premarital conceptions. The analysis demonstrates that the problem giving rise to most of this negative bias is not with the method but with the sociocultural background of respondents, which encourages them to hide pregnancyrelated deaths to never-married women. These findings highlight the need for more research into ways of asking questions about pregnancy status of sisters, particularly the never-married sisters, who have died. This study not only found out that the sisterhood estimate of maternal mortality will contain a negative bias but also offered recommendations to improve reporting in future sisterhood surveys by identifying some important determinants of accurate reporting of maternal deaths. It then explored the possibilities for extending the sisterhood method. The main question asked in this regard was whether causes of maternal deaths could be studied using this method. It is concluded that though cause-of-death information obtained by the method will always be subject to some error, it can provide an indication of an overall distribution of causes of maternal deaths which can be of value to public health, particularly for the planning of programs aimed at reducing maternal mortality and for evaluation of such programs over time

Rapidly progressing and resistant warts in an immuno-competent male

Cutaneous warts are common skin conditions caused by different specific strains of the human papilloma virus (HPV), mostly affect children as localized lesion on the hands and feet. They are slowly progressing and disseminated lesions are found in immuno-compromised situations. Usually majority of warts disappear by few months to two years. This is a case of extensive, giant, rapidly progressing and resistant warts in an immuno-competent adult male.

Genotypic and Seasonal Variation in Plant Development and Yield Attributes in Tomato (Lycopersicon esculentum Mill.) Cultivars

Morphological attributes and yield of eight genotypes of tomato namely, J-5, Binatomato-5, BARItomato-7, CLN-2026, CLN-2366, CLN-2413, CLN-2418 and CLN-2443 were studied over three seasons. Effects of seasonal and genotypic variations and their combination on plant height, number of primary branches per plant, number of flower clusters per plant, number of fruit clusters per plant, number of fruits per plant, individual fruit weight, fruit yield were significant. Fruit yield and almost all the morphological attributes of tomato genotypes were at peak in winter followed by pre-winter and summer season. Over three seasons, the genotype CLN-2413 produced the highest fruit yield followed by BARI tomato-7 producing the tallest plants with maximum number of primary branches and the highest number of fruits per plant. The genotypes Binatomato-5, CLN-2026 and CLN-2418 ranked 3rd and CLN-2366 and CLN-2443 ranked 4th with respect to yield performance. The genotype J-5 produced the lowest number of fruits per plant and fruit yield. In winter, fruits number and yield were highest in CLN-2413 while BARI tomato-7 carried the statistically same rank

Paclobutrazol and bulb size effect on onion seed production

Field experimentation was done at Bangladesh Agricultural University, Mymensingh during, 2005-2006 to evaluate doses of paclobutrazol (PBZ) and bulb size of onion for their effect on growth and seed production of onion. Onion variety "Taherpuri" with three-bulb sizes viz., small, medium and large was used. Doses of PBZ were 20, 40, 80 ppm and no PBZ was used as control. A two-factor experiment was laid out in a randomized complete block design with three replications. PBZ application significantly reduced plant height, number of tillers per bulb, number of leaves per plant and length of scape. Number of flowers, umbels per bulb, umbel diameter, 1000-seed weight and seed yield were not influenced by PBZ concentrations used. Plant height, number of leaves per plant, length of scape, effective fruits per umbel, percentage of fruit set and seed yield were positively influenced by bulb size of onion. Variable interactive effects of PBZ dose and bulb size for different traits were recorded

Crop water requirement at different growing stages of pineapple production in BRIS soil

The BRIS (Beach Ridges Interspersed with Swales) soils are the sandy marine deposits at the east coast of Peninsular Malaysia. The area is less suitable for usual field crops. Pineapple (Ananas comosus) may be introduced in the area for commercial cultivation. An experiment was conducted in the glass house condition of UPM. Pineapple plants were nurtured in the lysimeters, filled with BRIS soil, to assess the water requirements at different growth stages. Highest requirement of irrigation water was found 2.43 mm/day in initial stage (1). Subsequent development stage (2), mid-stage (3) and ripening stage (4) required smaller amount of irrigation water (approximately 1.55 mm/day). The daily average evapotranspiration (ETc) was 0.83 mm/day in Stage 1, followed by 0.73 mm/day in Stage 2. The lowest ETc was found 0.65 mm/day in Stage 3. The estimated crop coefficient (K ) was found maximum 0.51 in initial stage. The Kc values showed a continuous decreasing trend up harvesting time. The second highest Kc value was 0.37 in development stage followed by 0.33 in mid-stage and minimum 0.30 during ripening stage

Potential Use of Sea Water for Pineapple Production in BRIS Soil.

An experiment was conducted to determine the response of four sea water treatments on an improved pineapple genotype “N- 36” grown in Beach Ridges Interspersed with Swales (BRIS) soil. Sea water treatments were prepared by substitution of K with Na ions i.e., 0% (in control), 15%, 30% and 60% of required K doses were replaced by Na ions from sea water. Treatment effects were non-significant up to 30% sodium replacement from sea water. Na replacement (60%) showed significant impact on different growth parameters at different stages (8-10 months after planting). However, the fruit yield, the final target of crop harvest was not adversely affected at significance level. Therefore, sea water irrigation can easily fulfil 60% dose of potassium fertilizer by sodium ions for the production of pineapple in BRIS soil

Efficiency of plant growth-promoting rhizobacteria (PGPR) for the enhancement of rice growth

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replacechemical fertilizers, pesticides, and supplements. Here, we have isolated and characterized the PGPR from the rhizosphere soil of rice field for the enhancement of growth of rice. Rhizosphere soils were collected from different areas of Mymensingh in Bangladesh. Ten isolates of bacteria, designated as PGB1, PGB2, PGB3, PGB4, PGB5, PGT1, PGT2, PGT3, PGG1 and PGG2, were successfully isolated and characterized. Subsequently, to investigate the effects of PGPR isolates on the growth of rice, a pot culture experiment was conducted. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21 days of inoculation. Isolates PGB4, PGT1, PGT2, PGT3, PGG1 and PGG2 induced the production of indole acetic acid (IAA), whereas only PGT3 isolate was able to solubilize phosphorus. Most of isolates resulted in a significant increase in plant height, root length, and dry matter production of shoot and root of rice seedlings. Furthermore, PGPR isolates remarkably increased seed germination of rice. Among the ten isolates, PGB4 and PGG2 were found almost equally better in all aspects such as dry matter production, plant height and root length of rice, and IAA production. Isolate PGT3 was also found to be promising in IAA production having an additional property of phosphate solubilization. The present study, therefore, suggests that the use of PGPR isolates PGB4, PGG2 and PGT3 as inoculant biofertilizers might be beneficial for rice cultivation as they enhanced growth of rice, and induced IAA production and phosphorus solubilization