Assessing soil biodiversity across Great Britain: national trends in the occurrence of heterotrophic bacteria and invertebrates in soil

An assessment of the biodiversity of soils was a component of the Countryside Survey 2000 (CS2000). This was the first integrated survey of soil biota and chemical properties at a national scale. A total of 1052 soil samples were collected across Great Britain during CS2000 and analysed for a range of soil microbial and invertebrate characteristics resulting in the production of a series of robust datasets. A principal objective was to use these datasets to investigate relationships between soil biota and environmental factors such as geographical location, vegetation, land use, land cover, soil type and pollutant levels as first stages in characterising the inherent biodiversity of British soils and investigating the potential of soil biodiversity as indicators of soil health at a regional or national scale. Preliminary results for culturable heterotrophic, invertebrate taxa, Acari, Collembola and Oribatid mites are presented here to illustrate the nature of the data collected and the patterns of soil biodiversity in relation to large-scale regional, vegetation and soil characteristics across the British countryside.

Hyperplasia and apoptosis. Opposing cellular processes that regulate the response of the rabbit bladder to transient outlet obstruction

BACKGROUND

Partial obstruction of the rabbit urethra induces rapid bladder growth. This growth is characterized by hypertrophy of smooth muscle cells in addition to hyperplasia of cells in the urothelium and serosa. The local synthesis of growth factors has been proposed to be influential in this growth since partial outlet obstruction rapidly increases the bladder's expression of basic fibroblast growth factor, while suppressing the expression of transforming growth factor-beta. Upon release of the outlet obstruction, the hypertrophied bladder regresses to its normal weight. Here, we examined whether regression of the hypertrophied rabbit bladder involves apoptosis (programmed cell death) of specific cellular elements and whether the expression of growth factors is altered concomitant with apoptotic cell deletion.

EXPERIMENTAL DESIGN

Regressing rabbit bladders were analyzed for markers of apoptosis, including DNA fragmentation and histology. An in situ enzymatic immuno-histochemical procedure was utilized to localize apoptotic cells in these tissues. Finally, Northern blot analysis was used to identify changes in the expression of basic fibroblast growth factor and transforming growth factor-beta during bladder regression.

RESULTS

Regressing rabbit bladders demonstrated the characteristic electrophoretic "ladder" pattern of DNA fragmentation associated with apoptosis. An in situ technique to distinguish cells with degraded nuclear DNA identified apoptosis only within the urothelium and serosal lamina of the regressing bladders. RNAs extracted from regressing bladders exhibited decreased expression of basic fibroblast growth factor mRNA as well as increased expression of transforming growth factor-beta 1 mRNA when compared with RNAs from hypertrophied bladders.

CONCLUSIONS

We conclude that hyperplasia and apoptosis are opposing cellular processes that mediate the bladder's response to short-term obstructive stimuli and that local synthesis of growth-promoting and growth-inhibitory factors may be responsible for initiating both of these responses.

Pharmacological responses of rabbit urinary bladder after subtotal cystectomy

Partial cystectomy is used clinically in specific circumstances. There have been some reports indicating that the bladder following subtotal cystectomy can regenerate to a certain degree. The present study investigates the physiology and pharmacology of bladder regeneration at eight weeks after resection of a major part of the bladder body in rabbits. The following studies were performed on control and cystectomy bladders: 1) in vivo cystometry (prior to and four weeks after the operation, and before the sacrifice at eight weeks); 2) sequential muscle strip study (the strips were obtained by dividing bladder transversely into upper body, lower body, mid-bladder, upper base and lower base); and 3) in vitro whole bladder studies. The results can be summarized as follows: 1) grossly there was no regeneration of the bladder body; the cystometric capacity was increased slowly after the operation primarily due to increased size and capacity of the bladder base. 2) The contractile response of the subtotal cystectomized bladder body to field stimulation and bethanechol stimulation was less than the response of normal bladder body. 3) The contractile response to epinephrine showed that the ratio of alpha/beta adrenergic response was much greater in the cystectomy bladder than in the normal bladder. 4) In the whole bladder study, the intravesical pressure response to field stimulation was about the same in both groups, the response to bethanechol was less for cystectomized bladder, and the response to methoxamine was greater for the cystectomized bladder. 5) The ability of cystectomy bladder to empty in response to both field stimulation and bethanechol was impaired whereas the control bladder fully emptied to both field stimulation and bethanechol. In conclusion, over the eight week period following subtotal cystectomy the capacity increased via distention (and hypertrophy) of the bladder base area as opposed to regeneration of the bladder body.

Electroresection followed by neodymium-YAG laser photocoagulation of the dog prostate for establishment of safety parameters

Electroresection of the prostate followed by Nd-YAG laser coagulation of residual prostate was carried out in eight dogs. All dogs voided spontaneously without significant bleeding in the immediate postoperative period. At the time of sacrifice in 6 to 8 weeks, no damage to adjacent tissue was seen on microscopic examination. Re-epithelization had occurred. This study suggests that the addition of neodymium-YAG coagulation to residual tissue after TURP in humans can be done safely.