Length-weight relationship of the freshwater clam, Galatea paradoxa (born 1778) from the Volta Estuary, Ghana.

The length-weight relationship of the threatened freshwater clam, Galatea paradoxa (Born 1778) from the Volta Estuary, Ghana was studied over a two-year period, from March 2008 to February 2010, to aid in the development of stock assessment models for the sustainable management of the remaining clam stock. Data reported in this study were collected at monthly intervals and covered varying depths of the Estuary ranging from 0.5 to about 10 m. Overall, a total of 5276 clams with shell lengths ranging from 3.40 to 89.24 mm and total weight from 0.10 to 154.00 g were sampled during the study period. The length-weight relationships were highly significant (p < 0.0001) for all the months and the b-values ranged from 2.023 (January 2010) to 3.874 (June 2009). The calculated b-values indicated that clams exhibited different growth patterns at different periods but overall, the pooled samples of 5276 individuals exhibited an isometric growth pattern (b = 3.003). The observed monthly growth patterns exhibited by G. paradoxa appeared to be largely influenced by the reproductive cycle of the organism. During the periods leading to spawning, the clams generally exhibited positive allometric growth patterns (weight increasing faster than length) which appeared to be strongly linked to the build-up of proteins and carbohydrates in their tissues. Successive negative allometric growth patterns (length increasing faster relative to weight) were, however, observed from March to June 2008 and from December 2009 to February 2010, which are possibly indicative of the loss in tissue weight that occurs as a direct result of the spawning process. It will thus be suitable to institute a close season to coincide with the spawning period of the clams to avoid the harvesting of clams during the spawning period which will enhance future recruitment of the clam stock.

Relationship between gonad maturation and heavy metal accumulation in the clam, Galatea paradoxa (Born 1778) from the Volta estuary, Ghana.

The relationship between gonadal development and the concentrations of four heavy metals Mn, Zn, Fe and Hg in the tissues of the clam Galatea paradoxa was evaluated at the Volta estuary, Ghana, over an 18-month period. Metal concentrations in the clam tissues were highly variable over the sampling period and seemed to be influenced by the reproductive cycle of the clam. Mn concentrations varied over a wide range from 49 to 867 µg/g and exhibited a significant positive correlation with gonadal development (p = 0.0146, r(2) = 0.3190). Zn and Fe concentrations ranged from 13 to 59 µg/g and 79 to 484 µg/g, respectively and both revealed negative relationships between gonad development and metal accumulation (Zn (p = 0.0554, r(2) = 0.0554) and Fe (p = 0.1040, r(2) = 0.1567)). Hg concentrations ranged from 0.026 to 0.059 µg/g over the sampling period and exhibited a slight positive relationship between gonadal development and metal accumulation (p = 0.0861, r(2) = 0.1730).

Distribution and environmental impacts of metals and natural radionuclides in marine sediments in-front of different wadies mouth along the Egyptian Red Sea Coast.

Forty-four marine sediment samples were collected in-front of wadis mouth along the Egyptian Red Sea coast: Wadi El-Hamra, Wadi El-Esh, Wadi Abu-Shaar, Wadi El-Gemal and Wadi Khashir (Hamata). Several investigations of natural activity and trace metals of surface sediments were carried out. Distributions of naturally occurring radioactive materials (NORM) of (226)Ra, (232)Th and (40)K in the marine sediments were determined using NaI (Tl) γ-ray spectrometry. The average activities (range) of natural radionuclides in all wadis in the studied areas are 27.38 (18-48) Bq kg(-1) for (226)Ra, 38.45 (34-110) Bq kg(-1) for (232)Th and 419.4 (214-641) Bq kg(-1) for (40)K. These results are in agreement with earlier reported data. A comparison of radionuclide activities in the sediment of the studied areas and in other coastal and aquatic environments is given. The radiation hazard parameters (absorbed dose rate, radium equivalent activity and external hazard index) are calculated and compared with the reported data. The results of measurements will serve as base line data and background reference level for Egyptian coastlines.

Mercury accumulation in the clam, Galatea paradoxa (Born 1778) at the Volta estuary, Ghana.

The concentration of mercury in the tissues of the clam, Galatea paradoxa at in the Volta estuary, Ghana, were analysed over an 18-month period, from March 2008 to August 2009. The concentrations were well below the International Human Consumption Advisory Limit of THg (0.5 µg/g wet weight). The concentrations in the tissues of the different clam size classes were between 6 and 18 times lower than the WHO Safety Reference Standard. Variation in the mean mercury concentration in the different clam size classes was not significant (p > 0.05) for clams from Aveglo but were highly significant (p < 0.0001) for clams from Ada, indicating a possible effect of size on accumulation. G. paradoxa is therefore suitable for human consumption based on the WHO Safety Reference Standards.

Indapamide is superior to thiazide in the preservation of renal function in patients with renal insufficiency and systemic hypertension.

The long-term effects of indapamide or hydrochlorothiazide on blood presssure and renal function were examined in patents with impaired renal function and moderate hypertension. Both drugs controlled hypertension and blood pressure remained normal during the 2 years of the study. Despite this comparable control of hypertension, indapamide therapy was associated with a 28.5 +/- 4.4% increase in creatinine clearance, whereas treatment with hydrochlorothiazide was associated with a 17.4 +/- 3.0% decrease in creatinine clearance. The results of the study indicate that indapamide is superior to hydrochlorothiazide in the treatment of patients with impaired renal function and moderate hypertension.

Comparison between the effects of indapamide and hydrochlorothiazide on creatinine clearance in patients with impaired renal function and hypertension.

The long-term effects of indapamide or hydrochlorothiazide on blood pressure and renal function were examined in patients with impaired renal function and moderate hypertension. Both drugs controlled hypertension and blood pressure remained normal during the 2 years of the study. Despite this comparable control of hypertension, indapamide therapy was associated with a 28.5 +/- 4.4% increase in creatinine clearance while treatment with hydrochlorothiazide was associated with a 17.4 +/- 3.0% decrease in creatinine clearance. The results of the study indicate that indapamide is superior to hydrochlorothiazide in the treatment of patients with impaired renal function and moderate hypertension.

Effects of the antiprogesterone RU 486 in normal women. I. Single-dose administration in the midluteal phase.

The response to a single oral dose of the antiprogesterone RU 486 was studied in the midluteal phase in 26 normal women. Each subject received a dose between 50 and 800 mg RU 486 on days 6 to 8 after the luteinizing hormone surge and blood samples were taken over the following 48 hours. Another group of five patients received a single oral dose of 200 mg RU 486 and blood sampling was extended for 14 days. Menses were induced in all women but one within 3 days after RU 486 administration. Two distinct patient populations emerged. In nine of the subjects, there was a single bleeding episode and the treatment cycle was significantly shorter (p less than 0.05) than the following cycle. In 16 of these 25 patients a second bleeding episode occurred 19.0 +/- 0.8 days after the luteinizing hormone surge. The total treatment cycle was significantly prolonged (p less than 0.05) when compared with the following cycle. In the group with a single bleeding episode, there was a significant decline in follicle-stimulating hormone, estradiol, and progesterone over the 48-hour sampling period, but there was no change in these values in the group with two bleeding episodes. These two groups could not be separated on the basis of RU 486 dose or serum levels. After the four higher doses, there was a dose-dependent rise in serum prolactin. There were no alterations in mean cortisol values with the three lower doses, but there was a significant increase at 24 and 48 hours after the higher doses. Serum levels of RU 486 were maximal between 1 and 4 hours and the half-life of serum RU 486 was determined to be 24 hours.

Effects of the antiprogesterone RU 486 in normal women. II. Administration in the late follicular phase.

RU 486, a synthetic steroid with antiprogesterone receptor activity, was used to investigate the importance of progesterone on gonadotropin secretory dynamics in the midcycle of the normal menstrual cycle. Six normally cycling women were followed for three consecutive cycles. During each cycle, blood samples were obtained beginning on day 10 and continued until menses. After a control cycle, 100 mg RU 486 was given orally between days 10 and 17. The patients were followed for a posttreatment cycle with no medication. When RU 486 was given before the midcycle, the luteinizing hormone surge was delayed by 15.0 +/- 2.1 days after ingestion of the last pill, resulting in cycles of 40.6 +/- 2.6 compared with 28.0 +/- 2.3 days (p less than 0.01). During RU 486 administration and at the time a normal luteinizing hormone surge was anticipated, an attenuated luteinizing hormone/follicle-stimulating hormone surge was noted that was not followed by a rise in progesterone. After the attenuated surge a normal luteinizing hormone/follicle-stimulating hormone level occurred, with a normal rise in progesterone. Estradiol levels during RU 486 administration decreased during treatment, indicating a possible direct action of RU 486 on the ovary.