Effects of exogenous glutathione on the quality of chilled bull semen.

Glutathione (GSH) at concentrations of 0.0 (control), 0.5, 1.0, 2.0 and 3.0 mM was added to chilled bull semen to determine its effects on the keeping quality of semen used for artificial insemination (AI). The semen was preserved with egg yolk citrate extender. All samples were stored at 4-8 degrees C for 5 days. Sperm motility and proportion of abnormal acrosome were assessed daily. Sperm motility was significantly (p < 0.01) higher in the semen treated with 0.5 mM glutathione than in untreated semen on each day. The optimum sperm motility (>or=50%) for AI was retained significantly (p < 0.01) for 3 days in 0.0, 0.5, 1.0 and 2.0 mM glutathione treated semen, whereas in 0.3 mM glutathione-treated semen, sperm motility was 46.8% for 3 days. Acrosomal damage was significantly (p < 0.01) reduced after addition of 0.5 mM GSH in the preserved semen. Bull semen can be preserved in chilled condition for 5 days with 0.5 mM GSH with sperm motility above 40% and 12% acrosome abnormality.

Removal of arsenic from contaminated soils using different salt extractants.

This study presents an environmental-friendly and cost effective method for the extraction of arsenic from contaminated soils. Laboratory experiments using inorganic salts, potassium phosphate (KH2PO4), potassium chloride (KCl), potassium nitrate (KNO3), potassium sulfate (K2SO4), and sodium perchlorate (NaClO4) were evaluated as arsenic extractants. An Andosol soil was artificially contaminated with arsenite [As(III)] and arsenate [As(V)]. The soil was washed in a batch process with different salt solutions in the pH range 3-11 for 24 hours at 20 degrees C. Among the various potassium and sodium salts tested, KH2PO4 was found to be highly effective in extracting arsenic from As(III)-soil attaining more than 80% and 40% from As(V)-soil in neutral pH range. Other salts were particularly ineffective in extraction of arsenic from both soils. More arsenic was extracted more from the As(III)-soil than the As(V)-soil.

Radioimmunoassay of milk progesterone as a tool for fertility control in smallholder dairy farms.

This study focused on the use of radioimmunoassay of progesterone in milk for the diagnosis of post-partum ovarian cyclicity and accurate detection of oestrus and non-pregnancy in cows in the artificial insemination (AI) programme in Bangladesh. In Investigation 1, milk samples were collected on day 0 (day of AI), day 9-13 and day 21-24 from 444 milking cows of various breeds presented for the first postpartum insemination by 413 farmers living at 182 villages/regions in Mymensingh District from 6 AI centres and sub-centres. Each cow was then examined three times after each AI until it stopped returning to oestrus. Sixty to 90 days after the last AI, the cows were examined per rectum to confirm the pregnancy. Milk progesterone data on day 21-24 contributed to a clear diagnosis with respect to non-pregnancy in 100% cows, indicating a possible use of this progesterone assay for identifying non-pregnant cows in AI programmes. In Investigation 2, milk progesterone was monitored two times in a month with a 10-day interval in 88 cows. The samples were taken between 10 days after calving and the first detected oestrus, followed by two more samples 10 days apart. The proportion of cows accurately detected in oestrus was 30%. Another 30% were stated to be in oestrus when they were not (false positive) and 40% were not detected when they were in oestrus (false negative). The mean intervals between calving and oestrus and between calving luteal activity were 40 to 362 days (median=120, n=82) and 34 to 398 (median=111, n=64) days, respectively. The body condition scores at calving and at the initiation of luteal activity influenced the interval between calving and luteal activity (p < 0.05). Cows suckled twice daily initiated luteal activity earlier than their counterparts suckled several times daily (p < 0.05). Determination of progesterone in milk on day 21-24 is a good means for detecting non-pregnant cows.

Arsenic and heavy metal contamination of vegetables grown in Samta village, Bangladesh.

Drinking of arsenic (As) contaminated well water has become a serious threat to the health of many millions in Bangladesh. However, the implications of contamination of agricultural soils from long-term irrigation with As-contaminated groundwater for phyto-accumulation in food crops, and thence dietary exposure to As, and other metals, has not been assessed previously in Bangladesh. Various vegetables were sampled in Samta village in the Jessore district of Bangladesh, and screened for As, Cd, Pb, Cu and Zn by inductively coupled plasma emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). These local food products are the basis of human nutrition in this region and of great relevance to human health. The results revealed that the individual vegetables containing the highest mean As concentrations microg x g(-1)) are snake gourd (0.489), ghotkol (0.446), taro (0.440), green papaya (0.389), elephant foot (0.338) and Bottle ground leaf (0.306), respectively. The As concentration in fleshy vegetable material is low. In general, the data show the potential for some vegetables to accumulate heavy metals with concentrations of Pb greater than Cd. Some vegetables such as bottle ground leaf, ghotkol, taro, eddoe and elephant foot had much higher concentrations of Pb. Other leafy and root vegetables, contained higher concentrations of Zn and Cu. Bioconcentration factors (BCF) values, based on dry weight, were below 1 for all metals. In most cases, BCF values decreased with increasing metal concentrations in the soil. From the heavily As-contaminated village in Samta, BCF values for As in ladies finger, potato, ash gourd, brinjal, green papaya, ghotkol and snake gourd were 0.001, 0.006, 0.006, 0.014, 0.030, 0.034 and 0.038, respectively. Considering the average daily intake of fresh vegetables per person per day is only 130 g, all the vegetables grown at Samta had Pb concentrations that would be a health hazard for human consumption. Although the total As in the vegetables was less than the recommended maximum intake of As, it still provides a significant additional source of As in the diet.

A comparison of trace element concentrations in cultured and wild carp (Cyprinus carpio) of Lake Kasumigaura, Japan.

The concentrations of 13 elements were determined in the muscle, liver, intestine, kidney, and gonads of cultured and wild carp caught at two sites in Lake Kasumigaura, Japan, between September 1994 and September 1995. Despite having a reputation for being heavily polluted, the carp were not heavily burdened with metals. Our results suggest that despite their dietary differences, the wild and cultured fish were accumulating and distributing metals in the same manner and that aquaculture practices are not increasing metal concentrations in these fish. Metal concentrations were lowest in muscle, and did not exceed established quality standards for fish. The differences in metal concentrations between cultivated and wild carp are negligible and should pose no health problems for consumers of either type of fish.

Arsenic contamination in Bangladesh groundwater: a major environmental and social disaster.

In attempting to eliminate disease caused by drinking polluted surface water, millions of shallow surface wells were drilled into the Ganges delta alluvium in Bangladesh. The latest statistics indicate that 80% of Bangladesh and an estimated 40 million people are at risk of arsenic poisoning-related diseases because the ground water in these wells is contaminated with arsenic. The clinical manifestations of arsenic poisoning are myriad, and the correct diagnosis depends largely on awareness of the problem. Patients with melanosis, leuco-melanosis, keratosis, hyperkeratosis, dorsum, non-petting edema, gangrene and skin cancer have been identified. The present article reviews the current arsenic contamination of ground water, hydrological systems, groundwater potential and utilization and environmental pollution in Bangladesh. This paper concludes by clarifying the main actions required to ensure the sustainable development of water resources in Bangladesh.

Sustained low-efficiency dialysis for critically ill patients requiring renal replacement therapy.

BACKGROUND: The replacement of renal function for critically ill patients is procedurally complex and expensive, and none of the available techniques have proven superiority in terms of benefit to patient mortality. In hemodynamically unstable or severely catabolic patients, however, the continuous therapies have practical and theoretical advantages when compared with conventional intermittent hemodialysis (IHD). METHODS: We present a single center experience accumulated over 18 months since July 1998 with a hybrid technique named sustained low-efficiency dialysis (SLED), in which standard IHD equipment was used with reduced dialysate and blood flow rates. Twelve-hour treatments were performed nocturnally, allowing unrestricted access to the patient for daytime procedures and tests. RESULTS: One hundred forty-five SLED treatments were performed in 37 critically ill patients in whom IHD had failed or been withheld. The overall mean SLED treatment duration was 10.4 hours because 51 SLED treatments were prematurely discontinued. Of these discontinuations, 11 were for intractable hypotension, and the majority of the remainder was for extracorporeal blood circuit clotting. Hemodynamic stability was maintained during most SLED treatments, allowing the achievement of prescribed ultrafiltration goals in most cases with an overall mean shortfall of only 240 mL per treatment. Direct dialysis quantification in nine patients showed a mean delivered double-pool Kt/V of 1.36 per (completed) treatment. Mean phosphate removal was 1.5 g per treatment. Mild hypophosphatemia and/or hypokalemia requiring supplementation were observed in 25 treatments. Observed hospital mortality was 62.2%, which was not significantly different from the expected mortality as determined from the APACHE II illness severity scoring system. CONCLUSIONS: SLED is a viable alternative to traditional continuous renal replacement therapies for critically ill patients in whom IHD has failed or been withheld, although prospective studies directly comparing two modalities are required to define the exact role for SLED in this setting.

Seasonal variation in frequency of dividing cells of freshwater phytoplankters.

The frequency of dividing cells (FDC) of a natural phytoplankton community was studied seasonally in a freshwater pond to which water directly from Lake Kasumigaura was supplied. Phytoplankton samples were collected every 3 h at three depths (5, 30 and 75 cm) over 24 h periods in each of the four seasons and examined for FDC, cell size and abundance. Dominant phytoplankton species were Synedra ulna, Cyclotella kutzingiana, Chlamydomonas cingulata and Oscillatoria tenuis with Melosira italica, Cryptomonas ovata, and Synechococcus sp. being seasonally abundant. All species showed a similar FDC pattern related to the light-dark period that is a moderately phased division with the maximum FDC between 21:00-03:00.

Extraction of arsenic in a synthetic arsenic-contaminated soil using phosphate.

An environment-friendly and cost-effective extraction method has been studied for the removal of arsenic from contaminated soil. A yellow-brown forest soil was contaminated with arsenic(V) and used as a model soil. Among various potassium and sodium salts, potassium phosphate was most effective in extracting arsenic, attaining more than 40% extraction in the pH range of 6-8 with minimum damage to the soil properties. Exchange mechanism is proposed for the extraction of arsenic from soil by phosphate. Sequential extraction shows that phosphate is effective in extracting arsenic of Al- and Fe-bound forms. Arsenic of residual form was not extracted. Arsenic was efficiently extracted by phosphate solution of pH 6.0 at 300 mM phosphate concentration and at 40 degrees C.

Observations on the effects of caged carp culture on water and sediment metal concentrations in lake Kasumigaura, Japan.

The concentrations of 24 elements in the sediment and associated water column were monitored at two sites, one an area of intensive cage culture of carp, the other a wild site far from known cage culture areas, in Lake Kasumigaura, Japan, between September 1994 and September 1995. The concentrations of most elements in Lake Kasumigaura are mostly sub-parts per billion, except those for Ca, Fe, K, Mg, Na, P, and Si. The concentrations of Cd, Co, Cu, Mn, Ni, Pb, V, and Fe in Lake Kasumigaura are higher than the values in Lake Mashu, Lake Shikotsu, and Lake Biwa, and comparable to the levels in open ocean. Statistically significant differences in metal concentrations were observed between the culture and wild sites, with metal concentrations consistently higher at the culture site. Although cage culture of carp in the Lake Kasumigaura system may be causing localized increase in metal concentrations in the sediments, we must treat the results with caution, since the concentrations of metals observed in the sediments in 1995 were lower than those observed in 1979 for all metals at both sampling sites. In conclusion, further study of the concentrations of metals in the lake as a whole must be undertaken before the differences between the culture and wild sites can be proved, or disproved, to be the result of carp culture.

Effects of environmental factors on the seasonally change of phytoplankton populations in a closed freshwater pond.

The effect of environmental factors affecting the population dynamic of phytoplankton population was studied seasonally in a closed freshwater pond with the natural water of Lake Kasumigaura, Japan. The predominant phytoplankton species in the pond were classified as Oscillatoria tenuis, Synedra ulna, Chlamydomonas cingulata and Cyclotella kutzingiana, with dominant species of Melosira italica, Synechococcus sp. and Cryptomonas ovata. The most important limiting factor for filament length and cell size of most of the phytoplankton community was temperature. Availability of most nutrients had profound effects on the phytoplankton growth as nonlimiting factors. Based on our results, it is suggested that cell cycle progression was also temporally regulated by a multiplicity of external factors such as temperature, nutrients, dissolved oxygen (DO) and pH. At high pH and high temperature, consistent increase of cell division of some phytoplanketers such as Synedra, Cyclotella, Chlamydomonas and Melosira occurs, and there also may be species-specific responses for other species of phytoplankters. In addition, the cell divisions of phytoplankters are differentially regulated in different phytoplankton species.

Effect of dexamethasone on the estrous cycle length in Black Bengal goats (Capra hircus ).

In an experiment to examine the relationships between adrenals and reproductive cycle, 10 mg dexamethasone (a synthetic glucocorticoid) were injected intramuscularly twice daily for 10 d to four Black Bengal goats, beginning on Day 11 of the synchronized estrous cycle. The extended length of the sexual cycle was monitored by the clinical signs of anestrus. Laparotomy was performed to examine the status of the ovary of an 8, 9, 10 and 8 d extended cycle, respectively. The length of the next cycle was normal. Endogenous cortisol values were suppressed for 11, 13, 20 and 24 d, respectively. It is thought that dexamethasone caused prolonged luteal function either by the suppression of prostaglandin F(2)alpha synthesis or by the suppression of pituitary stimulation of follicular growth.

Suppression of LH response to gonadotrophin-releasing hormone or oestradiol by ACTH(1-24) treatment in anoestrous ewes.

Stress is known to result in lowered female reproductive efficiency. The objective of this study was to examine how increased pituitary-adrenal activity may influence gonadotrophin release in anoestrous ewes. Various doses (0.06-1.0 mg) of a synthetic adrenocorticotrophic hormone (ACTH(1-24)) preparation were injected into ewes 30 min or 3 h before an i.v. injection of 500 ng gonadotrophin-releasing hormone (GnRH). The LH response to GnRH given 30 min after ACTH(1-24) was similar to that after GnRH alone, whereas the response 3 h after ACTH(1-24) was significantly lower, irrespective of the dose of ACTH(1-24). At 30 min and 3 h after ACTH(1-24) the concentrations of cortisol exceeded 50 nmol/l compared with baseline values of less than 10 nmol/l. The effect of ACTH(1-24) on oestradiol-induced LH release was also examined. Those ewes receiving 0.8 mg ACTH(1-24) depot and 50 micrograms oestradiol benzoate simultaneously had a preovulatory-type increase in LH 14-20 h later, similar to when oestradiol benzoate was given alone. None of the ewes receiving an additional 0.8 mg ACTH(1-24) depot 10 h after oestradiol benzoate had increases in LH concentration. The cortisol concentrations in all ewes receiving either one or two injections of ACTH(1-24) were greater than 35 nmol/l at 10 h after the oestradiol injection. However, concentrations of progesterone increased from 0.9 +/- 0.3 (S.E.M.) nmol/l at the time of the second ACTH(1-24) injection to 2.1 +/- 0.3 nmol/l after 2 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary investigations into the endocrine systems of subfertile cattle: location of a common lesion (rate-limiting step).

Dairy cows with a variety of clinical conditions were investigated in an attempt to identify the cause(s) of subfertility. Sequential or simultaneous injections of 20 micrograms gonadotrophin-releasing hormone (GnRH), 1 mg oestradiol benzoate and 0.06 mg ACTH(1-24) into five clinical cases of ovarian follicular cysts, two cases of poor body condition and one case of lameness and into control cows revealed a failure in the LH positive-feedback response to oestradiol in all eight clinical cases, but in only two out of twelve control cows. Two of the clinical cases and the two non-responding control cows had high or rising initial progesterone concentrations which would explain the absence of response. All cows studied responded similarly to GnRH and ACTH(1-24). It is suggested that hypothalamus-pituitary control of LH release may involve a rate-limiting step (in the oestradiol positive-feedback system) and that lesions at this point result in subfertility in a variety of clinical situations.

Effect of betamethasone treatment on luteal lifespan and the LH response to GnRH in dairy cows.

Betamethasone (a synthetic glucocorticoid, 15 mg) was administered i.m. twice daily for 10 days to 4 regularly cycling dairy cows, beginning on Day 10 of the oestrous cycle. Luteal function, monitored by plasma progesterone, was extended by 7, 9, 19 and 20 days, respectively. Luteal function in the next cycle was normal. Endogenous cortisol values were suppressed for 14, 13, 34 and 27 days, respectively. Pituitary responsiveness to 20 micrograms GnRH was assessed by LH measurement on Days -1, +3 and +7 relative to the start of betamethasone treatment. There was a progressive decrease in peak LH concentrations after each GnRH challenge compared to control cows. Hourly measurements of PGF-2 alpha metabolite during the expected period of luteolysis failed to reveal normal increases. It is suggested that betamethasone caused prolonged luteal function, either by directly inhibiting PGF-2 alpha release, or by suppressing pituitary stimulation of follicular growth and hence lowering oestradiol concentrations, since it is known that PGF-2 alpha and oestradiol act synergistically to cause luteolysis.

Effect of various veterinary procedures on plasma concentrations of cortisol, luteinising hormone and prostaglandin F2 alpha metabolite in the cow.

Five commonly practised veterinary procedures were studied: Palpation per rectum of the reproductive tract, intramuscular injection, single venepuncture, repeated venepuncture and jugular vein catheterisation. Plasma cortisol concentrations increased from baseline values of approximately 2 ng/ml to maximum mean values between 6.5 +/- 2.5 ng/ml and 13.8 +/- 5.6 ng/ml approximately 13 to 27 minutes after each manipulation. Baseline values occurred approximately 80 minutes later. In the control bleeding periods unacclimatised cows initially had high values of plasma cortisol (5 to 10 ng/ml) which returned to baseline after two hours, ie, before beginning any procedure. There were no statistically significant changes in luteinising hormone concentrations. The concentration of 13,14 dihydro, 15-keto prostaglandin F2 alpha (PGFM) increased from 61.0 +/- 4.6 pg/ml to 209.8 +/- 152.1 pg/ml in three out of five cows palpated on days 16 and 19 of the oestrous cycle. Increases did not occur in five other cows palpated during the follicular phase, nor in five cows palpated on day 12. However, after palpation on day 8, one animal did have concentrations of PGFM similar to those occurring during spontaneous release on days 18 to 20 of the oestrous cycle.