Comparative genomic study of arachnid immune systems indicates loss of beta-1,3-glucanase-related proteins and the immune deficiency pathway

Analyses of arthropod genomes have shown that the genes in the different innate humoral immune responses are conserved. These genes encode proteins that are involved in immune signalling pathways that recognize pathogens and activate immune responses. These immune responses include phagocytosis, encapsulation of the pathogen and production of effector molecules for pathogen elimination. So far, most studies have focused on insects leaving other major arthropod groups largely unexplored. Here, we annotate the immune-related genes of six arachnid genomes and present evidence for a conserved pattern of some immune genes, but also evolutionary changes in the arachnid immune system. Specifically, our results suggest that the family of recognition molecules of beta-1,3-glucanase-related proteins (βGRPs) and the genes from the immune deficiency (IMD) signalling pathway have been lost in a common ancestor of arachnids. These findings are consistent with previous work suggesting that the humoral immune effector proteins are constitutively produced in arachnids in contrast to insects, where these have to be induced. Further functional studies are needed to verify this. We further show that the full haemolymph clotting cascade found in the horseshoe crab is retrieved in most arachnid genomes. Tetranychus lacks at least one major component, although it is possible that this cascade could still function through recruitment of a different protein. The gel-forming protein in horseshoe crabs, coagulogen, was not recovered in any of the arachnid genomes; however, it is possible that the arachnid clot consists of a related protein, spätzle, that is present in all of the genomes.

Flow cytometric sexing of spider sperm reveals an equal sperm production ratio in a female-biased species

Producing equal amounts of male and female offspring has long been considered an evolutionarily stable strategy. Nevertheless, exceptions to this general rule (i.e. male and female biases) are documented in many taxa, making sex allocation an important domain in current evolutionary biology research. Pinpointing the underlying mechanism of sex ratio bias is challenging owing to the multitude of potential sex ratio-biasing factors. In the dwarf spider, Oedothorax gibbosus, infection with the bacterial endosymbiont Wolbachia results in a female bias. However, pedigree analysis reveals that other factors influence sex ratio variation. In this paper, we investigate whether this additional variation can be explained by the unequal production of male- and female-determining sperm cells during sperm production. Using flow cytometry, we show that males produce equal amounts of male- and female-determining sperm cells; thus bias in sperm production does not contribute to the sex ratio bias observed in this species. This demonstrates that other factors such as parental genes suppressing endosymbiont effects and cryptic female choice might play a role in sex allocation in this species.

Polyandrous females acquire indirect benefits in a nuptial feeding species

The relative force of direct and indirect selection underlying the evolution of polyandry is contentious. When females acquire direct benefits during mating, indirect benefits are often considered negligible. Although direct benefits are likely to play a prominent role in the evolution of polyandry, post-mating selection for indirect benefits may subsequently evolve. We examined whether polyandrous females acquire indirect benefits and quantified direct and indirect effects of multiple mating on female fitness in a nuptial gift-giving spider (Pisaura mirabilis). In this system, the food item donated by males during mating predicts direct benefits of polyandry. We compared fecundity, fertility and survival of singly mated females to that of females mated three times with the same (monogamy) or different (polyandry) males in a two-factorial design where females were kept under high and low feeding conditions. Greater access to nutrients and sperm had surprisingly little positive effect on fitness, apart from shortening the time until oviposition. In contrast, polyandry increased female reproductive success by increasing the probability of oviposition, and egg hatching success indicating that indirect benefits arise from mating with several different mating partners rather than resources transferred by males. The evolution of polyandry in a male-resource-based mating system may result from exploitation of the female foraging motivation and that indirect genetic benefits are subsequently derived resulting from co-evolutionary post-mating processes to gain a reproductive advantage or to counter costs of mating. Importantly, indirect benefits may represent an additional explanation for the maintenance of polyandry.

Effects of within-colony competition on body size asymmetries and reproductive skew in a social spider

Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did not increase over the course of the experiment, suggesting that body size variation is shaped at an early stage. This might facilitate task specialization within colonies and ensure colony-level reproductive output by early allocation of reproductive roles. We suggest that reproductive skew in social spiders may be an adaptation to sociality selected through inclusive fitness benefits of allo-maternal care as well as colony-level benefits maximizing colony survival and production.

Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae)

Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task specialization, but in distinctly different ways: Stegodyphus sarasinorum showed behavioural asymmetries at the individual level, that is, individual spiders that had attacked prey once were more likely to attack prey again, independent of their body size or hunger level. In contrast, Anelosimus eximius showed no individual specialization, but showed differentiation according to instar, where adult and subadult females were more likely to engage in prey attack than were juveniles. We found no evidence for division of labour between prey attack and web maintenance. Different solutions to achieve task differentiation in prey attack for the two species studied here suggest an adaptive value of task specialization in foraging for social spiders.

The genetic architecture of fitness in a seed beetle: assessing the potential for indirect genetic benefits of female choice

Background

Quantifying the amount of standing genetic variation in fitness represents an empirical challenge. Unfortunately, the shortage of detailed studies of the genetic architecture of fitness has hampered progress in several domains of evolutionary biology. One such area is the study of sexual selection. In particular, the evolution of adaptive female choice by indirect genetic benefits relies on the presence of genetic variation for fitness. Female choice by genetic benefits fall broadly into good genes (additive) models and compatibility (non-additive) models where the strength of selection is dictated by the genetic architecture of fitness. To characterize the genetic architecture of fitness, we employed a quantitative genetic design (the diallel cross) in a population of the seed beetle Callosobruchus maculatus, which is known to exhibit post-copulatory female choice. From reciprocal crosses of inbred lines, we assayed egg production, egg-to-adult survival, and lifetime offspring production of the outbred F1 daughters (F1 productivity).

Results

We used the bio model to estimate six components of genetic and environmental variance in fitness. We found sizeable additive and non-additive genetic variance in F₁ productivity, but lower genetic variance in egg-to-adult survival, which was strongly influenced by maternal and paternal effects.

Conclusion

Our results show that, in order to gain a relevant understanding of the genetic architecture of fitness, measures of offspring fitness should be inclusive and should include quantifications of offspring reproductive success. We note that our estimate of additive genetic variance in F₁ productivity (CV_A = 14%) is sufficient to generate indirect selection on female choice. However, our results also show that the major determinant of offspring fitness is the genetic interaction between parental genomes, as indicated by large amounts of non-additive genetic variance (dominance and/or epistasis) for F₁ productivity. We discuss the processes that may maintain additive and non-additive genetic variance for fitness and how these relate to indirect selection for female choice.

Survival benefits select for group living in a social spider despite reproductive costs

The evolution of cooperation requires benefits of group living to exceed costs. Hence, some components of fitness are expected to increase with increasing group size, whereas others may decrease because of competition among group members. The social spiders provide an excellent system to investigate the costs and benefits of group living: they occur in groups of various sizes and individuals are relatively short-lived, therefore life history traits and Lifetime Reproductive Success (LRS) can be estimated as a function of group size. Sociality in spiders has originated repeatedly in phylogenetically distant families and appears to be accompanied by a transition to a system of continuous intra-colony mating and extreme inbreeding. The benefits of group living in such systems should therefore be substantial. We investigated the effect of group size on fitness components of reproduction and survival in the social spider Stegodyphus dumicola in two populations in Namibia. In both populations, the major benefit of group living was improved survival of colonies and late-instar juveniles with increasing colony size. By contrast, female fecundity, female body size and early juvenile survival decreased with increasing group size. Mean individual fitness, estimated as LRS and calculated from five components of reproduction and survival, was maximized for intermediate- to large-sized colonies. Group living in these spiders thus entails a net reproductive cost, presumably because of an increase in intra-colony competition with group size. This cost is traded off against survival benefits at the colony level, which appear to be the major factor favouring group living. In the field, many colonies occur at smaller size than expected from the fitness curve, suggesting ecological or life history constraints on colony persistence which results in a transient population of relatively small colonies.

Inbreeding avoidance in spiders: evidence for rescue effect in fecundity of female spiders with outbreeding opportunity

Selection by inbreeding depression should favour mating biases that reduce the risk of fertilization by related mates. However, equivocal evidence for inbreeding avoidance questions the strength of inbreeding depression as a selective force in the evolution of mating biases. Lack of inbreeding avoidance can be because of low risk of inbreeding, variation in tolerance to inbreeding or high costs of outbreeding. We examined the relationship between inbreeding depression and inbreeding avoidance adaptations under two levels of inbreeding in the spider Oedothorax apicatus, asking whether preference for unrelated sperm via pre- and/or post-copulatory mechanisms could restore female fitness when inbreeding depression increases. Using inbred isofemale lines we provided female spiders with one or two male spiders of different relatedness in five combinations: one male sib; one male nonsib; two male sibs; two male nonsibs; one male sib and one male nonsib. We assessed the effect of mating treatment on fecundity and hatching success of eggs after one and three generations of inbreeding. Inbreeding depression in F1 was not sufficient to detect inbreeding avoidance. In F3, inbreeding depression caused a major decline in fecundity and hatching rates of eggs. This effect was mitigated by complete recovery in fecundity in the sib-nonsib treatment, whereas no rescue effect was detected in the hatching success of eggs. The rescue effect is best explained by post-mating discrimination against kin via differential allocation of resources. The natural history of O. apicatus suggests that the costs of outbreeding may be low which combined with high costs of inbreeding should select for avoidance mechanisms. Direct benefits of post-mating inbreeding avoidance and possibly low costs of female multiple mating can favour polyandry as an inbreeding avoidance mechanism.

Tissue culture supernatants from human islets of Langerhans activate the oxidative burst response of human monocytes in vitro

Macrophages play a major role in the pathogenesis of insulin-dependent diabetes mellitus in animals. These cells are the first to invade the pancreas and macrophage-eradicating treatments reduce the incidence of the disease. In humans, however, their role is less clear. In this study we investigated the hypothesis that the pancreatic environment per se could activate macrophages. Tissue culture supernatants from human islets of Langerhans were tested for chemotactic activity and oxidative burst response in monocytes isolated from healthy adults. Preincubation with the supernatants enhanced the oxidative burst response evoked by fMLP (up to 379%) and opsonized zymosan (up to 173%). The activity decreased by dilution and was no longer detectable at 1:16. No increased activity was seen in supernatants from a number of other human endocrine and non-endocrine primary cells, suggesting a factor specific for islet tissue. The increased oxidative burst response could partially be eliminated by heat- and proteinase K treatment, suggesting that the activity could be of polypeptide nature. The factor could not be absorbed by polyvalent rabbit antibodies directed towards a variety of cytokines not by a mixture of high-titer anti-cytokine antibodies. It is possible that islet factors could also promote such monocyte activation in vivo in monocytes attracted to the islets of Langerhans by other means. This could contribute to the development of insulin-dependent diabetes in humans.

Retroperitoneal fibrosis treated with methylprednisolon pulse and disease-modifying antirheumatic drugs

The conventional treatment of patients with ureteric obstruction due to retroperitoneal fibrosis (RF) is surgery in combination with long-term corticosteroids. This report describes 11 cases of RF with ureteric obstruction treated with methyl-prednisolon pulse therapy (MPPT) in combination with azathioprine or penicillamine following initial insertion of ureteral stents. The medial treatment suggested was successful in 7 patients, but only moderately effective in the last 4 patients. This principle of non-operative management of RF has not been previously reported.

A new patient weighted symptom score system (DAN-PSS-1). Clinical assessment of indications and outcomes of transurethral prostatectomy for uncomplicated benign prostatic hyperplasia

A patient weighted symptom score system, the Danish Prostatic Symptom Score (DAN-PSS-1), including a disease specific self administered quality of life questionnaire, is presented. The model was evaluated pre- and postoperatively in 29 patients apparently suffering from uncomplicated benign prostatic hyperplasia. The score system is based on the severity of 12 symptoms related to bladder storage and voiding function, and three questions related to sexual function (symptom score). For each of these parameters the patient must also evaluate its influence on his daily life (bother score). In the 29 patients with uncomplicated benign prostatic hyperplasia (BPH) bother scores exceeded symptom scores for the irritative symptoms but not for the obstructive symptoms, and surprisingly the symptom score was less improved than the bother score 6 months after transurethral resection of the prostate (TUR-P). Furthermore the postvoiding dribble was worsened after the operation. We find that this model, DAN-PSS-1, assists in creating a solid base for the indication for and the evaluation of treatment of uncomplicated BPH.

Trends in a Danish urologic department during the years 1979 and 1984

During recent years several international studies have shown increasing rates of prostatectomy over the past decade. In Denmark the number of prostatectomies increased by 43% in the period 1977-85. This development is still unexplained, but one of the answers is very intriguing, proposing a shift in indications for prostatectomy. Therefore we retrospectively examined the records of 207 patients in 1979 and 243 patients in 1984, admitted with a diagnosis of benign hyperplasia of the prostate (BPH). In these patients respectively 164 and 149 prostatectomies were performed in the same years, at the Department of Urology, Glostrup County hospital. We found no evidence of a change in indications towards a more liberal attitude as suspected, but in contrast, we discovered a more conservative attitude. Because the national rates since 1984 have been stable, we conclude, that the development in a specialized urologic Department can serve as a predictor for the development on a larger national scale.

Prostatectomy in Denmark. Regional variation and the diffusion of medical technology 1977-1985

In many countries prostatectomy is one of the most common surgical operations in elderly men. We used administrative data for the entire male population of Denmark to study temporal and regional variations in the use of prostatectomy from 1977 to 1985. The total annual number of prostatectomies increased by 43% during the period, when the transurethral procedure (TURP) gradually replaced traditional open surgery. TURP accounted for 56% of all operations in 1977 but increased its share to 92% in 1985. Substantial regional variations occurred with index values for prostatectomy in 72 recruitment areas ranging from 0.56 to 1.62 (SCV x 100 = 5.3). The amount of variation decreased during the process of technology diffusion, but remained at a relatively high level (as in other countries) even after the process had been completed (SCV x 100 = 5.1).

Is micturition disorder a pathogenic factor in acute epididymitis? An evaluation of simultaneous bladder pressure and urine flow in men with previous acute epididymitis

We evaluated 22 men 22 to 70 years old with previous acute epididymitis by pressure-flow study 3 to 12 months after the inflammation had resolved. Nine healthy men 20 to 62 years old were evaluated as controls. The patients had no symptoms from the lower urinary tract except for 2 men with slight prostatism. The maximum intravesical and maximum voiding pressures were elevated significantly in the patients compared to the controls (p less than 0.05). In most patients and in all of the controls the maximum urinary flow rates were within the normal range according to age. Because of the frequency of high voiding pressures in patients with previous acute epididymitis, this condition may be a pathogenic factor by promoting urethrovasal reflux. The high voiding pressures may be transmitted to the proximal urethra or in cases of a narrow and rigid bladder neck they may produce increased turbulence in the urine stream.

Biocompatibility of urinary catheters. Effect on complement activation

The ability of 2 brands of urinary catheters to activate the complement system in vitro as a marker of biocompatibility was investigated. Pieces of a silicone/latex catheter and an all-silicone catheter were incubated in human serum. Complement activation was tested in 2 enzyme immunoassays, one evaluating C3 activation and the other the terminal complement complex (TCC) formation. The silicone/latex catheter caused considerably more complement activation in both assays than did the all-silicone one. The findings are in agreement with previous results of tissue toxicity tests. The methods presented may prove valuable for the practical purpose of testing the biocompatibility of urinary catheters.

Prevention of urethral stricture formation after transurethral resection of the prostate: a controlled randomized study of Otis urethrotomy versus urethral dilation and the use of the polytetrafluoroethylene coated versus the uninsulated metal sheath

Stricture formation after transurethral prostatectomy was studied in a randomized clinical trial including 185 patients. The patients were allocated to either a 2-day urethral catheter-dilation or internal Otis urethrotomy and to an operation with either a polytetrafluoroethylene coated or an uninsulated metal resectoscope. Urethral stricture was defined as an obstruction resulting in a maximum urine flow rate of less than 15 ml. per second and not permitting the passage of a 21F cystoscope. The frequency of urethral strictures was significantly lower after Otis internal urethrotomy (4 per cent) than after a 2-day urethral catheter dilation (16 per cent). The incidence of stricture formation was similar in patients operated on with a polytetrafluoroethylene coated (8 per cent) and with an uninsulated metal (12 per cent) resectoscope sheath. The incidence of stricture formation was unrelated to age, duration of preoperative and postoperative catheterization, operating time and presence of urinary tract infection.

Ureteroscopy: results and complications

The results and complications of 100 consecutive ureteroscopy studies are reported. Introduction through the orifice or the intramural ureter failed in 11 per cent of the patients and in 14 per cent the ureteroscope could not be advanced up to the level of the lesion. Ureteroscopy was successful in 75 per cent of the patients and stone extraction was successful in 69 per cent. Complications occurred in 9 patients: 4 had an uncomplicated urinary tract infection, 4 had a ureteral perforation and 1 presented with ureteral stenosis at the site of the extracted stone a few weeks later. At followup 1 to 3 months after ureteroscopy clinical examination, excretory urography and/or renography revealed no further late sequelae.

Human umbilical vein for vascular access in chronic hemodialysis

Since 1979 we have used human umbilical vein graft as the ultimate vascular access for hemodialysis in patients with chronic renal failure. In 24 patients 33 graft fistulas were performed. Several complications were encountered. Among these infection was the most serious, occurring in seven grafts. All these grafts were removed and never used for hemodialysis. Thrombosis occurred 25 times, and five grafts were lost because of this, whereas 20 grafts had successful thrombectomy and continued to function. Aneurysm formation occurred four times, two grafts were lost. Stenosis was seen in three cases, one graft was lost. In the material 26 grafts were used for hemodialysis and a median function time of 8.5 months was obtained. At the end of the observation period 10 grafts were open, eight were used for hemodialysis, two were not used because of successful transplantation. The umbilical vein graft is an acceptable alternative as vascular access where conventional methods of fistula formation have been exhausted.

The 125I-Hippuran renogram in rabbit kidneys after graded warm ischaemia

125I-Hippuran renography was performed after temporary renal arterial clamping in contralateral nephrectomized rabbits. Mean renograms for the experimenttal groups were calculated for 0, 1, 1 1/2, 2, 2 1/2 and 3 h of warm ischaemia. The appearance phase, the 1 min uptake phase and excretion ratio were evaluated. The kidney function was monitored by serum-creatinine. Warm ischaemia of 1, 1 1/2 and 2 h resulted in a late maximum peak and delayed excretion, and for the last group in an accumulation curve. The uptake capacity was normal for these groups. Protracted ischaemia of 2 1/2 and 3 h affected also the appearance and uptake phase resulting in a slower and decreased Hippuran uptake of 50% and 34% respectively. Duration of warm ischaemia and changes in the renogram were well correlated. A normal uptake phase predicts restitution of the kidney function and 100% survival.

The effect of chlorpromazine pretreatment on the vascular function of kidneys damaged by warm ischaemia and cold storage in Collins' solution

Vascular resistance was determined in 40 rabbit kidneys after graded warm ischaemia up to 60 minutes and preservation in Collins' solution for 24 and 48 hours. Half of the animals were treated with chlorpromazine 3.5 mg/kg before induction of the ischaemia. Vascular function was determined during short-term perfusion with TIS-U-SOL at 4 degrees C. The experiments showed that warm ischaemia of 30 and 60 minutes duration gave an increase in vascular resistance. The increase was, however, smaller in kidneys pretreated with chlorpromazine. Preservation in Collins' solution for 24 and 48 hours did not change this correlation. Determination of the weights and thereby formation of oedema showed that all kidneys preserved had a small increase in weight. No difference was found between pretreated kidneys and untreated kidneys. It is concluded that pretreatment with chlorpromazine is capable of diminishing vascular contraction during the warm ischaemic period and that preservation in Collins' solution for up to 48 hours does not alter this beneficial effect.

Renographic evaluation of kidney preservation with chlorpromazine

The effect of chlorpromazine pretreatment of kidneys then damaged by warm ischemia was investigated. The ischemia was inflicted on rabbit kidneys by renal arterial occlusion of 1 1/2 and 3 hours' duration after contralateral nephrectomy. Pretreatment with chlorpromazine, 3.5 mg/kg, was given intravenously before arterial clamping. I-125 Hippuran renography was performed before clamping, immediately after clamp release, and at 2, 4, 6, and 14 days later. Serum creatinine and survival rate were followed. Comparison with untreated control groups was made. The effect on tubular function was investigated by measuring I-125 Hippuran uptake in pretreated slices of renal cortex (compared with untreated contralateral kidney) 48 hr after circulation was restored to the ischemic kidney. Chlorpromazine pretreatment improved recovery from ischemic damage: the renograms showed improved Hippuran uptake after clamp removal, and return to normal was faster. Survival rate after 3 hr of ischemia increased from 1/10 to 6/10 in the pretreated group, and serum creatinine recovered earlier. Hippuran uptake in slices of cortex showed no significant improvement because of pretreatment. It is concluded that the beneficial effect of chlorpromazine pretreatment must be because of decreased vascular resistance, leading to long-lasting increased postischemic renal blood flow.

The effect of chlorpromazine pretreatment on the vascular resistance in kidneys following warm ischaemia

In studies of 45 rabbits pretreated by chlorpromazine, clamping of the renal artery was performed. Chlorpromazine 3.5 mg/kg was given intravenously 15 min before arterial clamping. The duration of the clamping period ranged from 0 to 180 min. After removal of the kidneys the influence of the pretreatment on the vascular resistance was examined in perfusion studies. Resistance patterns were measured during hypothermic perfusion. The results were compared with an identical group without pretreatment. The vascular resistance rose with the duration of clamping but was lower than in the control group. The maximal resistance attained after 60 min of clamping was approximately 50% lower. In another series of chlorpromazine pretreated animals clamping of the renal artery for 180 min was followed by reestablishment of the circulation for 24 and 48 hours. Perfusion studies were performed on kidneys after removal. The results were compared with a group without pretreatment. The vascular resistance was found to return to normal values more rapidly when the animals had been pretreated with chlorpromazine.

The effect of chlorpromazine pretreatment on renal function and pathology in kidneys damaged by warm ischaemia

The influence of chlorpromazine pretreatment on kidney function and survival after temporary occlusion of the renal artery was investigated. Three hours of clamping of the renal artery and contralateral nephrectomy was performed in a group of ten rabbits pretreated with 3.5 mg/kg chlorpromazine and compared with a previously published control group of untreated animals. Chlorpromazine pretreatment improved survival. The kidney function, estimated by serum-creatinine, showed an earlier onset of function and the surviving animals regained nearly normal function. Histological examination revealed mild to moderate ischaemic changes, whereas the control group showed more profound damages.

The effect of chlorpromazine and heparin pretreatment on kidney viability and function after warm ischaemic damage

The influence of chlorpromazine and heparin pretreament on kidney function and histology has been investigated in rabbit kidneys damaged by warm ischaemia. Three experimental groups were investigated. One in which animals were pretreated with heparin, one group pretreated with heparin and chlorpromazine, and one group without pretreatment. The left renal artery was temporarily clamped for 3 hours and the kidneys recirculated. After 2-3 weeks a delayed contralateral nephrectomy was made, and after another 2-3 weeks all kidneys were studied histologically. Kidney function was measured by determination of serum-creatinine. The experiments showed, that all animals survived with impaired renal function. Pretreatment with chlorpromazine and heparin did not affect the final results. Secerity of the ischaemic damage, histologically evaluated was the same in all groups.

The influence of warm ischaemia on renal function and pathology

Temporary occlusion of the left renal artery for 0-180 min after contralateral nephrectomy was undertaken in 51 rabbits. The correlation between the injury of warm ischaemia and kidney function, survival and histology was evaluated. After 0, 60, 90 and 120 min occlusion, all animals survived and normal renal function was restored. After occlusion for 150 min only 4 of 10 animals survived, and normal renal function was not re-established. 180 min occlusion was detrimental to the animals. Only one out of ten survived with severely damaged kidney function. Histological findings were consistent with the experimental observations of renal function.

The integrity of tubular cell function after preservation in Collins' or Sacks' solution

Collins' solution is an excellent medium for kidney preservation by simple cold storage before transplantation. Efforts by Sacks et al. to improve this technique by modifying the composition seemed promising. A comparison between ability of these two media to preserve the tubular cell was attempted. The viability of the tubular cells was evaluated by measuring the 125 I Hippuran uptake in cortex slices taken from kidneys preserved for 24 and 48 hr in the respective solutions. Kidneys exposed to as well as kidneys not exposed to warm ischaemia were used. Collins' solution was found to be superior in protecting the cell function. Nonetheless intracellular oedema during preservation was greater after preservation in this solution as compared with cells preserved in Sacks' solution.

The influence of an agonal phase on the vascular resistance of the kidney measured during hypothermic perfusion studies

The influence of the agonal phase on the rabbit renal vascular resistance during warm ischemia was studied in 24 hypothermic perfusion experiments. The agonal phase was induced by tracheal clamping in anesthetized animals. The interval from strangulation to cardiac arrest was, on average, 8.1 min. Kidneys were removed between 0 and 60 min after cardiac arrest. Comparison with an earlier study where warm ischemia was induced by clamping of the renal artery shows that the agonal phase is not a significant factor in that renal vascular resistance is not increased.

The collateral blood flow and hippuran clearance of the rabbit kidney after occlusion of the renal artery

The collateral blood flow to the rabbit kidney was determined by two methods: (1) measurement of the venous flow after clamping of the renal artery and (2) Hippuran clearance of the clamped kidney. The collateral blood flow was found to be 0.012 ml/min/g kidney equivalent to 0.2% of the entire blood flow to the rabbit kidney. Compared with collateral blood flow in other mammals (as humans and dogs) with a collateral flow of 6.2% of the normal flow, the collateral blood flow in the rabbit is very modest. The cranial ureteric artery contributes more than 90% of the entire blood flow, while capsular perforants, important in other mammals, play no role in the supply of the rabbit kidney. Only 50% of the collateral blood flow passes the tubular system. Flow to the medulla calculated from Hippuran clearance was 35% greater than flow to the cortical part of the kidney. The subcapsular cortical tubuli were able to absorb Hippuran from the peritoneal fluid and surrounding tissues after the kidney was dissected free from its surroundings and all vessels severed. Absorption corresponded to an arbitrary serum flow of 0.0002 ml/min/g.

The uptake of hippuran in kidney slices employed as a viability test

125J Hippuran uptake in slices from rabbit kidneys was measured in kidneys damaged by warm ischaemia alone as well as by warm ischaemia combined with 24 hours of cold ischaemia. The Hippuran uptake was calculated as the ratio between radioactivity in the slices and the activity in the incubation medium as a slice/medium ratio (S/M). S/M was unchanged after 15 minutes, 30 minutes and 1 hour of warm ischaemia, while in kidneys exposed to 2 hours of warm ischaemia a 15% decrease in S/M ratio compared with control values was noted. A 53% decrease was observed after 3 hours of warm ischaemia and 73% and 91% after 4 and 5 hours respectively. Twenty-four hours of cold ischaemia alone did not alter the Hippuran uptake, but prolonging this with 15 minutes of warm ischaemia precipitated a significant fall (25%) in S/M. This value remained constant during the first hour of warm ischaemia, but a fall of 64% was observed after 2 hours of warm and 24 hours of cold ischaemia. These findings were in agreement with experiments on kidneys damaged by arterial occlusion and recirculated. Two hours of warm ischaemia was the maximal damage the kidneys could endure and still regain normal function. After simple preservation methods with Collins solution for 24 hours, 1 additional hour of warm ischaemia was the maximal ischaemic damage the kidney was able to withstand. Hippuran uptake in kidney slices appears to be well correlated to the kidneys' ability to regain normal function after ischaemic damage.

The effect of temporary clamping of the renal vessels on the vascular resistance in rabbit kidneys

In studies of 45 rabbits, either the renal artery (35 animals), or the renal artery and vein (10 animals) were clamped in situ. The effect of the clamping--of the warm ischemia--on the vascular resistance of the kidney after reestablishment of the circulation was examined in perfusion studies made after removal of the kidneys from groups of 5 animals between 1 and 5 days after revascularization. Resistance patterns were measured during hypothermic perfusion. The results confirm earlier findings that vascular resistance increases in proportion to the duration of warm ischemia up to 60 min, but not thereafter. The renal vascular resistance falls over the days following revascularization, more slowly after longer periods of ischemia. Thus after 60 min of warm ischemia the vascular resistance became normal within 24 hours, but after 180 min of warm ischemia, the normal resistance range was not reached until 96 hours after reestablishment of the circulation. When both the renal artery and the renal vein were clamped, the pattern was the same but much less emphatic. The vascular resistance never attained such high values as seen after clamping of the renal artery alone, and became normal after 24 hours of revascularization, even when the period of warm ischemia was as long as 180 min.

Vascular resistance in hypothermically perfused kidneys damaged by warm ischemia

Vascular resistance was determined during hypothermic perfusion of rabbit kidneys after various periods of warm ischemia. Ischemia was induced by clamping of the renal artery, or of the renal artery and vein, in situ. Studies were made after periods of clamping ranging from 0 to 180 min. The perfusing fluid was 5% Dextran of low molecular weight in balanced saline solution (Tis-U-Sol), with addition of 5 mg % Papaverin. When the renal artery was clamped for more than 15 min, vascular resistance increased. Maximal resistance was reached after 60 min of clamping, and was 3 times as high as that value in the control group of kidneys which were not clamped. The vascular resistance attained after 60 min of clamping did not further increase when clamping was maintained for 180 min. When both the renal artery and the renal vein were clamped vascular resistance first increased after 30 min. Maximal resistance was reached after 60 min of clamping, but was only 1/2 of that level seen when the renal artery alone was clamped.

The effect of chlorpromazine pretreatment on tubular function in kidney preservation

The effect of Chlorpromazine pretreatment on tubular function was investigated. Hippuran uptake in cortex slices from rabbit kidneys was measured after one hour of incubation in a medium containing Hippuran. Before measurement the kidneys were exposed to varying periods of warm ischaemia or/and cooled and preserved for 24 hours in Collins solution. Chlorpromazine treated and untreated groups of animals were compared, the results obtained were identical in both groups. In contra distinction to these findings, addition of Chlorpromazine to the incubation fluid inhibited uptake of Hippuran in the kidney slices. The effects of pretreatment with Chlorpromazine on the kidney function after ischaemic damage were demonstrated. Serum-creatinine and survival were compared in a treated and an untreated group after 3 hours of temporary clamping of the renal artery. Pretreatment resulted in earlier onset of function and better survival. It is concluded that the antimetabolic effect of Chlorpromazine is opposed to its vasodilatory properties is of little practical importance for the viability of the kidney damaged by ischaemia.