Global CO2 emissions from dry inland waters share common drivers across ecosystems

Many inland waters exhibit complete or partial desiccation, or have vanished due to global change, exposing sediments to the atmosphere. Yet, data on carbon dioxide (CO2) emissions from these sediments are too scarce to upscale emissions for global estimates or to understand their fundamental drivers. Here, we present the results of a global survey covering 196 dry inland waters across diverse ecosystem types and climate zones. We show that their CO2 emissions share fundamental drivers and constitute a substantial fraction of the carbon cycled by inland waters. CO2 emissions were consistent across ecosystem types and climate zones, with local characteristics explaining much of the variability. Accounting for such emissions increases global estimates of carbon emissions from inland waters by 6% (~0.12 Pg C y-1). Our results indicate that emissions from dry inland waters represent a significant and likely increasing component of the inland waters carbon cycle.

Effects of whole-body heat on male germ cell development and sperm motility in the laboratory mouse

This study investigated the effects of high temperatures on male germ cell development and epididymal sperm motility of laboratory mice. In Experiment 1, adult males (n = 16) were exposed to whole-body heat of 37–38°C for 8 h day–1 for 3 consecutive days, whereas controls (n = 4) were left at 23–24°C. In Experiment 2, adult mice (n = 6) were exposed to 37–38°C for a single 8-h period with controls (n = 6) left at 23–24°C. Experiment 2 was conducted as a continuation of previous study that showed changes in spermatozoa 16 h after exposure to heat of 37–38°C for 8 h day–1 for 3 consecutive days. In the present study, in Experiment 1, high temperature reduced testes weights 16 h and 14 days after exposure, whereas by Day 21 testes weights were similar to those in the control group (P = 0.18). At 16 h, 7 and 14 days after exposure, an increase in germ cell apoptosis was noticeable in early and late stages (I–VI and XI–XII) of the cycle of the seminiferous epithelium. However, apoptosis in intermediate stages (VII–X) was evident 16 h after heat exposure (P < 0.05), without any change at other time periods. By 21 days, there were no significant differences between heat-treated groups and controls. Considerably more caspase-3-positive germ cells occurred in heat-treated mice 16 h after heat exposure compared with the control group (P < 0.0001), whereas 8 h after heat in Experiment 2, sperm motility was reduced with a higher percentage of spermatozoa showing membrane damage. In conclusion, the present study shows that whole-body heat of 37–38°C induces stage-specific germ cell apoptosis and membrane changes in spermatozoa; this may result in reduced fertility at particular times of exposure after heating.

Leaf oxalate content of Eucalyptus spp. and its implications for koalas (Phascolarctos cinereus) with oxalate nephrosis

Oxalate nephrosis is a leading disease of the Mount Lofty Ranges koala population in South Australia, but the cause is unclear. In other herbivorous species, a common cause is high dietary oxalate; therefore this study aimed to determine the oxalate content of eucalypt leaves. Juvenile, semimature and mature leaves were collected during spring from eucalypt species eaten by koalas in the Mount Lofty Ranges and compared with those from Moggill, Queensland, where oxalate nephrosis has lower prevalence. Total oxalate was measured as oxalic acid by high-performance liquid chromatography. The oxalate content of eucalypts was low (<1% dry weight), but occasional Mount Lofty leaf samples had oxalate levels of 4.68–7.51% dry weight. Mount Lofty eucalypts were found to be higher in oxalate than those from Queensland (P < 0.001). In conclusion, dietary oxalate in eucalypt leaves is unlikely to be the primary cause of oxalate nephrosis in the Mount Lofty koala population. However, occasional higher oxalate levels could cause oxalate nephrosis in individual koalas or worsen disease in those already affected. Further studies on the seasonal variation of eucalypt leaf oxalate are needed to determine its role in the pathogenesis of oxalate nephrosis in koalas.

Are male germ cells of the arid-zone hopping mouse (Notomys alexis) sensitive to high environmental temperatures?

In most mammalian species, the temperature of scrotal testes is several degrees lower than that of core body temperature due to the presence of a counter-current heat exchange between the coiled testicular artery and the pampiniform plexus of veins. Here we ask: have hopping mice developed a highly efficient cooling mechanism within their scrotal sac and/or germ cell resistance to high environmental temperatures? To investigate this, adult male sexually mature Notomys alexis were used to determine: (1) the temperature of the testes; (2) the extent of coiling of the testicular artery; (3) the effect of artificially induced cryptorchidism on spermatogenesis up to three weeks after surgery; and (4) the effect of whole body heat exposure of 37−38°C for 8 h per day for three consecutive days on germ cell apoptosis. The results showed that in hopping mice the testicular artery, unlike that in most other mammalian species, is not coiled although the temperature in the scrotum was found to be ~2°C lower than that of the abdomen. In cryptorchid males, 21 days after surgery, testes weights were reduced in three of five individuals but there was no statistically significant decrease after 16 h exposure to whole body heat (P = 0.07). Nevertheless, some impairment of spermatogenesis was evident in both the cryptorchid testes and in the testes after whole body heating. These results show that in hopping mice developing male germ cells are susceptible to degeneration when testes are exposed to high environmental temperatures. Thus adaptations of Notomys alexis to the arid zone have not involved any special adaptations for male germ cell survival in a hot environment. Behavioural adaptations may play a pivotal role in maintaining maximal male fertility in such extreme environmental conditions.

Renal tolerability of intermittent intravenous ibandronate treatment for patients with postmenopausal osteoporosis: a review

While intravenous (IV) bisphosphonates are well established in managing metastatic bone disease and hypercalcemia of malignancy, oral bisphosphonates are the primary treatment for postmenopausal osteoporosis. The availability of a well-tolerated, effective, IV bisphosphonate regimen for postmenopausal osteoporosis would increase physicians' options, allowing treatment of patients who cannot tolerate oral therapy, for whom oral bisphosphonates should be avoided or patients who are unable to comply with the oral dosing recommendations. Ibandronate is a potent, nitrogen-containing bisphosphonate, with proven efficacy and good tolerability when administered intermittently either orally or intravenously. Preclinical experience in animal models with IV ibandronate indicated that it had good renal tolerability. These data are supported by clinical pharmacology studies. Prolonged follow-up of patients receiving intermittent IV 15-30 second injections of 0.5-3 mg IV ibandronate has demonstrated no clinical evidence of renal toxicity in patients with postmenopausal osteoporosis. What is seen in controlled studies is not always the case in uncontrolled studies, however, no reports of renal failure have been received in post-marketing surveillance of >500,000 patients receiving IV ibandronate infusions in various indications including metastatic breast and prostate cancer. The good renal tolerability of IV ibandronate in patients with osteoporosis with glomerular filtration rates >30 mL/minute and without renal co-morbid conditions is reassuring.

437. Whole body heat stress induces selective germ cell apoptosis in mice

Introduction: In scrotal mammals, heat stress (43°C/ 20 min) to the scrotum results in germ cell death in the testes1, abnormal spermatozoa, and infertility2 whereas two days of whole body heating (36°C, 12 h/ day) reduces testes weight, sperm numbers and fertility3. The aim of the present study was to determine the intratesticular effects of whole body heating on germ cell maturation and apoptosis. Methods: C57BL/6 mice (n = 16) were housed at 37–38°C for 8 h/ day for 3 days while controls (n = 4) were kept at 23–24°C. Animals from heat treated (n = 4), and control groups (n = 1) were sacrificed at 16 h, 7, 14 and 21 days post exposure to heat. Testes were weighed and analysed by t-test. In testes from each animal, two sections 70µm apart were end labelled for TdT-mediated-dUTP nick (TUNEL). Apoptosis was determined in 200 seminiferous tubules by a colour threshold set in the particle analysis program (Olympus).The tubules were staged as I-VI (early), VII-VIII, IX-X and XI-XII (late) and results analysed using Wilcoxon test. Results: The weights of testes were significantly reduced in heat-treated animals (P < 0.05) at 16 h, 7 and 14 days with no significant difference at 21 days. Apoptosis was significantly higher in the heat-treated group in stages I-VI and XI-XII at 16 h, 7 and 14 days (P < 0.05). In addition, in stages VII-VIII and IX-X apoptosis was significantly higher at 16 h (P < 0.05) with no statistical difference between other time intervals. By day 21, the levels of apoptosis did not differ significantly from the controls in any of the stages (P > 0.05).Conclusion: Whole body heat stress can induce stage and cell specific degeneration of the germ cells in the seminiferous epithelium. The germ cells undergoing apoptosis are spermatogonia, primary spermatocytes and early spermatids. In addition, heat stress produces significant apoptosis of germ cells in the hormone dependent stages VII-VIII immediately after heat stress. (1) Rockett, J.C. et al. (2001) Biol. Reprod. 65:229–239. (2) Banks, S. et al. (2005) Reproduction 129:505–514. (3) Yaeram, J. et al. (2006) Reprod. Fert. Dev. 18:647–653.

Comparative study of sperm chromatin condensation in the excurrent ducts of the laboratory mouse Mus musculus and spinifex hopping mouse Notomys alexis

In most mammals, post-testicular sperm maturation is completed in the caput and corpus epididymides, with storage occurring in the cauda epididymides. However, in the spinifex hopping mouse, Notomys alexis, epididymal sperm transit is rapid and some sperm storage occurs in the distal region of the vas deferens. The aim of the present study was to determine whether the rapid progression of sperm into the vas deferens in the hopping mouse results in late sperm maturation. To determine this, sperm nuclei from the epididymides and vasa deferentia of laboratory and hopping mice were compared for: (1) thiol content after staining with monobromobimane (mBBr); (2) chromatin resistance to acid denaturation following incubation with acetic alcohol and staining with acridine orange; and (3) chromatin resistance to in vitro decondensation after incubation with 1% sodium dodecyl sulfate (SDS). It was found that, whereas laboratory mouse sperm completed chromatin condensation by the time they reached the cauda epididymidis, hopping mouse sperm nuclei from the vas deferens showed significantly less mBBr fluorescence and a greater proportion of sperm were resistant to decondensation with SDS than those in the cauda epididymidis. Therefore, the results of the present study indicate that, unlike in the laboratory mouse, hopping mouse chromatin condensation of spermatozoa continues in the vas deferens and this may be due, at least in part, to rapid epididymal transit.

Dietary aluminium and renal failure in the koala (Phascolarctos cinereus)

The study investigated the link between the potentially nephrotoxic levels of aluminium ingested in the natural diet of eucalypt leaves by koalas in the Adelaide Hills, South Australia, and the high incidence of renal failure in koalas within this habitat. Routine histology of kidney specimens revealed no pathologies at the light microscopic level and contrasted sharply with the clinical signs of renal failure. However staining with solochrome azurine and Perl's Prussian blue showed aluminium was present in some proximal convoluted tubules in all specimens. Aluminium was also found in bone samples. The presence of aluminium in bone and kidney tissues was confirmed using electron dispersive x-ray analysis with transmission and scanning electron microscopy. Ultrastructural changes, including a decrease in lysosomal numbers, were seen in proximal convoluted tubules and these changes were shown to coincide with the presence of aluminium. No aluminium was found in koalas that died from causes other than renal failure. It was concluded that renal failure in the koalas of the Adelaide Hills is characterised by the presence of aluminium in the kidneys and bone and it is probably related to the high levels of aluminium in their restricted diet of eucalypt leaves. However, it is not known if the presence of aluminium is the cause or effect of the renal failure. The study is the first account where aluminium ingested as part of the natural diet of mammals has been shown to accumulate in the animal and be implicated with nephrotoxicity.

Substance P-induced enhanced permeability of dura mater microvessels is accompanied by pronounced ultrastructural changes, but is not dependent on the density of endothelial cell anionic sites

Experimental data point to a determinant role for endothelial cell (EC) anionic sites in the regulation of vascular permeability. Previous studies have shown that EC anionic sites density is reduced in conditions of enhanced permeability. The pathophysiology of migraine and vascular headache encompasses dilatation of dural vessels and extravasation of plasma proteins. The current study was carried out to determine if the density of EC anionic sites is reduced in enhanced permeability of dural vessels. Enhanced permeability was chemically induced in rats by intravenous injection of substance P and was tested by assessing leakage of horseradish peroxidase (HRP). Anionic sites were labelled with cationic colloidal gold and their density was quantified from electron microscopy negatives. Experimental animals showed increased leakage of HRP from dural vessels. However, anionic sites in EC membranes (luminal and abluminal) showed no statistical differences when their mean densities in experimental and control animals were compared. The results indicate that in this model, factors other than the density of anionic sites may be important determinants in the permeability of dural vessels. Such factors may include structural alteration of ECs consistent with an increased permeability. In this study pronounced ultrastructural changes in ECs were noted in experimental animals including widening of intercellular junctions and an increase in the number of EC gaps and vesicles.

Evaluation of non-invasive techniques to assess vasoconstriction in healthy volunteers using methoxamine as a probe drug

Non-invasive methods for assessment of the vascular effects of antimigraine drugs were evaluated with respect to their utility, variability and sensitivity in a double-blind, placebo-controlled, three-period crossover study in six healthy volunteers using an intravenous vasoconstrictor, methoxamine, as a probe drug. Changes in the internal diameter of the brachial and radial arteries were measured using ultrasound which had low between-day and within-day coefficients of variation. Peak systolic velocity (PSV), time-averaged velocity (TAV), total flow, resistance (RI) and pulsatility indices (PI) were measured by Doppler from one arterial wave form. Whilst PSV and TAV increased with methoxamine, because of bradycardia, changes in PI and RI were difficult to interpret. An automatic oscillometric cuff, a mercury-in-silastic strain gauge method and the "Finapres", finger arterial blood pressure monitor were used to follow changes in systolic blood pressure (SBP). The strain gauge technique underestimated arm SBP compared to the oscillometric method but clearly showed drug-related increases whilst the Finapres did not reflect changes in blood pressure detected by the other methods.

Staged diabetes management. Toward an integrated model of diabetes care

This paper introduces a new and innovative approach to diabetes management in the primary-care setting. Staged diabetes management (SDM) represents a four-year effort to develop and test a data-based approach to diabetes management that could be easily adapted to a variety of health-care settings in which diabetes management is principally under the direction of primary-care physicians was limited access to specialists. After testing under controlled circumstances at the International Diabetes Center (Minneapolis, MN), SDM was subjected to substantial field trials under conditions that represent the scope and variety of primary-care practices in diabetes. The following represents the work of several investigators who independently undertook a review of SDM.

Occurrence of melanin in pheochromocytoma

Melanin or a melanin-like pigment was observed in six of 19 pheochromocytomas. The intracellular pigment was Fontana-positive, bleach-labile dark brown to black material and distinct from coincidental hemosiderin and lipochrome. Ultrastructural components of the pigmented tumors include melanosomes and premelanosomes. Two patients with pigmented tumors had associated von Hippel-Lindau syndrome, and one had neurofibromatosis. The occurrence of melanin and melanosomes in pheochromocytoma has not been previously reported in the English literature. It is probably a reflection of the neural crest origin of this neoplasm.

Collagenous colitis associated with chronic constipation

We present a case in which the classical histopathologic features associated with collagenous colitis were present throughout the colectomy specimen of a 69-year-old woman operated on for life-long intractable idiopathic constipation. This patient had never suffered from episodes of watery diarrhea. The reasons for this paradox are unclear, but suggest that a thickened collagen table and damaged surface epithelium may not be entirely specific pathologic findings marking the clinicopathological syndrome of collagenous colitis.

Properties of the extract and spicules of the dermatitis inducing sponge Neofibularia mordens Hartman

Skeletal components and the exudate of the sponge Neofibularia mordens, as well as four fractions of the extract were investigated. Possible causes, and management, of the contact dermatitis resulting from application of extract fractions were studied. Antimicrobial activity of the sponge extract fractions, together with their effect on small crustaceans, was determined. Two fractions exhibited strong neuroactivity on guinea-pig isolated intestine, octopus-arm nerve-muscle and crustacean cheliped nerve-muscle preparations.

Pigments, polysaccharides, and photosynthetic products of Phaeosaccion collinsii

Zoospores of Phaeosaccion collinsii averaged 70 µ3 and contained total N 2.24 pg, DNA 0.19, and chlorophyll a 0.62 pg per spore. In addition, chl c, "cis"-β-carotene, fucoxanthin, and violaxanthin were principal pigments and a minor unidentified carotene was present.Photosynthetic rates of zoospores were 0.37 × 10−12 g C per spore per hour, or 0.59 mg C per mg chl a per hour at 5°. The principal products of photosynthesis were mannitol and a water-soluble glucan.Carbohydrates in the thalli were fractionated and evidence is presented for the presence of a laminarin-like glucan, mannitol, myo- and scyllo-inositols. Alginate was absent.The relationship of P. collinsii to other algal groups is discussed and it is concluded that its affinities lie with the Chrysophyceae.