Mycobacterial infections after renal transplantation

Mycobacterial infections occurred in 11 of 633 (1.7 per cent) recipients of successful renal transplants. There were no cases of tuberculosis in patients receiving chemoprophylaxis, but amongst those who did not receive prophylaxis disease occurred in six of the 27 (22 per cent) high-risk patients. The major cause of morbidity during treatment was renal allograft rejection, largely due to reduction in immunosuppressive drug therapy.

Effect of intravenous infusion of atriopeptin 3 on immediate renal allograft function

Thirty-eight recipients of nineteen pairs of cadaveric kidneys were entered into a double-blind randomized study in which one recipient received a 12-hour intravenous infusion of Atriopeptin III (AP-3), a synthetic analogue of atrial natriuretic factor, commencing at release of the vascular clamps, and the other received a placebo infusion. In an initial dose ranging study, successive groups of six kidneys (3 pairs) were randomized to receive each of 0.0125, 0.025, 0.05 micrograms/kg/min AP-3 or placebo. Thereafter 20 kidneys (10 pairs) received 0.1 micrograms/kg/min or placebo. There was no discernable effect of AP-3 on allograft creatinine clearance or sodium excretion either when the highest dose of AP-3 was considered alone or when all doses were considered together. Averaged creatinine clearance over the period 0 to 24 hours after transplantation was 20.1 +/- 14.7 ml/min in patients receiving active treatment and 18.2 +/- 13.7 ml/min in those receiving placebo. Thus, despite the documentation of a protective effect of atrial natriuretic factor in animal models of renal ischemia, it is unlikely that intravenous infusion of AP-3 in this dose range will be of benefit in improving immediate renal allograft graft function.

Influence of hydrogen-consuming bacteria on cellulose degradation by anaerobic fungi

The presence of methanogens Methanobacterium arboriphilus, Methanobacterium bryantii, or Methanobrevibacter smithii increased the level of cellulose fermentation by 5 to 10% in cultures of several genera of anaerobic fungi. When Neocallimastix sp. strain L2 was grown in coculture with methanogens the rate of cellulose fermentation also increased relative to that for pure cultures of the fungus. Methanogens caused a shift in the fermentation products to more acetate and less lactate, succinate, and ethanol. Formate transfer in cocultures of anaerobic fungi and M. smithii did not result in further stimulation of cellulolysis above the level caused by H2 transfer. When Selenomonas ruminatium was used as a H2-consuming organism in coculture with Neocallimastix sp. strain L2, both the rate and level of cellulolysis increased. The observed influence of the presence of methanogens is interpreted to indicate a shift of electrons from the formation of electron sink carbon products to H2 via reduced pyridine nucleotides, favoring the production of additional acetate and probably ATP. It is not known how S. ruminantium exerts its influence. It might result from a lowered production of electron sink products by the fungus, from consumption of electron sink products or H2 by S. ruminantium, or from competition for free sugars which in pure culture could exert an inhibiting effect on cellulolysis.

The prevalence of hyperlipidemia in renal transplant recipients. Associations with immunosuppressive and antihypertensive therapy

To determine the extent of persisting hyperlipidemia in renal transplant recipients receiving modern maintenance immunosuppressive and antihypertensive therapy we compared plasma levels of total and high-density lipoprotein and triglyceride in 275 renal transplant recipients with stable graft function with age- and sex-matched groups from the local general population (n = 4055). Total cholesterol and triglyceride were higher in transplanted patients in all age groups, but the difference was much more striking in women. Plasma levels of HDL cholesterol were similar or slightly lower in transplanted patients. Association with parameters of graft function, immunosuppressive therapy, and antihypertensive therapy were studied within the transplanted population using multiple regression. Total cholesterol was significantly and independently associated with age, sex, diuretic therapy, and urinary protein. In 127/134 (95%) of patients the diuretic was a loop diuretic. None of the other classes of antihypertensive drug was independently associated with serum cholesterol. The only variables significantly associated with HDL cholesterol were sex and the plasma creatinine. Plasma triglyceride was significantly and independently associated with both diuretic therapy and beta-blocker therapy and with age, urinary protein excretion, and plasma albumin. Plasma cholesterol, HDL cholesterol, and triglyceride levels were almost identical in patients receiving triple therapy (cyclosporine 3-5 mg/kg; prednisolone 7-10 mg o.d.; azathioprine 1-1.5 mg/kg) to those in patients receiving conventional immunosuppression (prednisolone 7-10 mg o.d.; azathioprine 2-2.5 mg/kg). Thus these results do not support the existence of a persisting long-term effect of cyclosporine on plasma cholesterol and triglyceride at these doses of the drug. The more striking abnormality of plasma cholesterol and triglyceride in females is unexplained but might be connected with greater sensitivity to low doses of corticosteroids.

Effect of coumarin on glucose uptake by anaerobic rumen fungi in the presence and absence of Methanobrevibacter smithii

The effect of coumarin (1,2 benzopyrone) on glucose utilisation by the anaerobic rumen fungi Neocallimastix frontalis and N. patriciarum has been compared with the effect of p-coumaric acid. Both compounds largely inhibited glucose utilisation by N. patriciarum strain Cx when present in the medium at a concentration of 2.5 mM, and had a similar effect on N. frontalis strain RE1 at 5 mM. Although in earlier studies co-culturing rumen fungi with Methanobrevibacter smithii enhanced resistance to ionophores, no comparable protective effect of M. smithii was found in the present study.

Triple therapy immunosuppression in cadaveric renal transplantation

One hundred and ninety-two patients received 200 consecutive cadaver renal transplants (158 first and 42 regrafts) and were treated with triple therapy immunosuppression consisting of low-dose cyclosporin, azathioprine and prednisolone. One-year patient and graft survival rates were 95% and 82%, respectively. Against this low rate of graft loss, the proportion of rejection-free patients in the first 3 months was strongly related to matching for HLA-DR (P less than 0.01), although HLA-DR matching was not associated with improved graft survival. More grafts were lost to nonimmunological causes than to rejection, and these losses fell into three main categories, namely, losses in elderly and diabetic patients and losses due to renal vascular thrombosis. Thus, triple therapy immunosuppression appears to offer effective immunosuppression, resulting in good graft and patient survival, especially in highly sensitised patients or patients receiving regrafts. There are relatively few serious adverse effects, although elderly and diabetic patients experienced significant morbidity and mortality after transplantation.

Spontaneous rupture of renal allografts: the importance of renal vein thrombosis in the cyclosporin era

Spontaneous renal allograft rupture occurring within 14 days of transplantation occurred in 15 patients from 791 consecutive transplants. In each of eight patients treated with azathioprine and prednisolone there was pathological evidence of rejection and only two patients had thrombosis of the renal vein. Of the seven cases occurring in patients treated with triple therapy regimen (low dose cyclosporin, prednisolone and azathioprine), histological evidence of rejection was present in only three cases, but renal vein thrombosis was found in all seven. Spontaneous rupture of a transplanted kidney, a relatively uncommon complication, is more likely to be due to renal vein thrombosis than to rejection in the cyclosporin era.

Hypophosphataemia after renal transplantation: relationship to immunosuppressive drug therapy and effects on muscle detected by 31P nuclear magnetic resonance spectroscopy

Plasma phosphate values were examined in 72 renal transplant patients in a randomised trial of immunosuppression with azathioprine and prednisolone versus cyclosporin alone. From 21 to 77 days after transplantation, in patients with plasma creatinine concentrations of 75-150 mumol/l, mean plasma phosphate was 0.98 (SEM 0.04) mmol/l in cyclosporin-treated patients, compared with 0.65 (SEM 0.12) mmol/l in cyclosporin-treated patients receiving pulse methylprednisolone for rejection (P less than 0.003), and 0.68 (SEM 0.02) mmol/l in patients treated with azathioprine and prednisolone (P less than 0.001). There was no difference between the mean plasma creatinine of these groups of patients. A preliminary study by nuclear magnetic resonance spectroscopy of four patients with asymptomatic chronic hypophosphataemia showed reduced concentrations of intracellular phosphate in resting muscle, and further abnormalities developed on exercise. Thus, exogenous steroid administration is a major contributing factor of hypophosphataemia in the early post-transplant period. In addition chronic hypophosphataemia may be associated with reduced intracellular inorganic phosphate concentrations detectable by nuclear magnetic resonance spectroscopy, although these changes are not apparently associated with any clinical symptoms.

Degradation of barley straw, ryegrass, and alfalfa cell walls by Clostridium longisporum and Ruminococcus albus

The recently isolated ruminal sporeforming cellulolytic anaerobe Clostridium longisporum B6405 was examined for its ability to degrade barley straw, nonlignified cell walls (mesophyll and epidermis) and lignified cell walls (fiber) of ryegrass, and alfalfa cell walls in comparison with strains of Ruminococcus albus. R. albus strains degraded 20 to 28% of the dry matter in barley straw in 10 days, while the clostridium degraded less than 2%. A combined inoculum of R. albus SY3 and strain B6405 was no more efficient than SY3 alone, and the presence of Methanobacterium smithii PS did not increase the amount of dry matter degraded. In contrast, with alfalfa cell walls as the substrate, the clostridium was twice as active (28% weight loss) as R. albus SY3 (15%). The percentages of dry matter degraded from ryegrass cell walls of mesophyll, epidermis, and fiber for the clostridium were 50, 47, and 32%, respectively, and for R. albus SY3 they were 77, 73, and 63%, respectively. Analyses of the predominant neutral sugars (arabinose, xylose, and glucose) in the plant residues after bacterial attack were consistent with the values for dry matter weight loss. Measurements of the amount of carbon appearing in the fermentation products indicated that R. albus SY3 degraded ryegrass mesophyll cell walls most rapidly, with epidermis and fiber cell walls being degraded at similar rates. Strain B6405 attacked alfalfa cell walls at a rate greater than that of any of the ryegrass substrates. These results indicate an unexpected degree of substrate specificity in the ability of C. longisporum to degrade plant cell wall material.

Skin cancer in renal transplant recipients

Skin cancer was found in 31 of 598 patients transplanted in Oxford. No cases occurred during the first 3 years after transplantation but the prevalence rose after 12 years to 18.2 per cent. The main risk factors predisposing to skin cancer were the time after transplantation and male sex. Comparison with data from other centres suggests that exposure to ultraviolet light is a major aetiological factor in the speed of development of skin cancer. As the incidence of new cases rose progressively with time in our patients, it would seem that skin cancer is likely to become a major clinical problem as more patients enjoy prolonged survival after renal transplantation. Preventative and screening measures should be taken by transplant units both in the UK and in other countries with similar temperate climates.

Antithymocyte globulin for steroid resistant rejection in renal transplant recipients immunosuppressed with triple therapy

Steroid resistant rejection, confirmed histologically, occurred in 35 of 187 consecutive cadaveric renal transplants treated with triple therapy (cyclosporin, azathioprine and prednisolone) in the Oxford Transplant Unit. Twenty-seven of these were treated with a rabbit antithymocyte globulin (ATG) and 19 showed recovery of function. The level of serum creatinine, the renal biopsy appearance and the requirement for dialysis at the start of ATG treatment did not predict which patients would respond to the therapy. One year after transplantation there was no significant difference between the mean plasma creatinine levels of those patients with steroid resistant rejection who had been given ATG and responded (151.6 mumol/l) and those who had responded to steroids alone (165.0 mumol/l). Adverse effects of ATG treatment included a mean fall in white cell count of 62.2% and a mean fall in platelet count of 45.1%. Two of the 27 patients who received ATG died (7.4% mortality). ATG would appear to be an effective treatment of steroid resistant rejection in patients receiving triple therapy immunosuppression, and graft function may subsequently be excellent in those patients who respond to treatment.

Hyperparathyroidism, hypertension and loop diuretic medication in renal transplant recipients

The associations between serum parathyroid hormone (PTH), blood pressure and hypotensive medication were analysed in 282 renal transplant recipients. Among patients with a normal concentration of serum creatinine there was no correlation between serum PTH and blood pressure but in those receiving hypotensive medication serum PTH was appropriately twofold greater than in those not taking hypotensive medication. Analysis revealed that the dominant contribution to this association was a specific association with loop diuretic therapy. When all patients were stratified according to creatinine clearance, serum PTH was always greater in patients receiving loop diuretics but this difference was particularly striking in the patients with the poorest graft function. It is postulated that loop diuretics exacerbate the hyperparathyroidism which complicates renal disease.

Enhanced resistance of anaerobic rumen fungi to the ionophores monensin and lasalocid in the presence of methanogenic bacteria

The presence of Methanobrevibacter smithii altered the susceptibility of the anaerobic fungi Neocallimastix frontalis and Piromonas communis to the carboxylic ionophores monensin and lasalocid. The ionophores depressed growth (measured by chitin accretion), the uptake of glucose and the production of H2, formate and acetate by the fungi growing axenically in semi-solid medium. In the presence of M. smithii, the sensitivity of the fungi to monensin and lasalocid was decreased. For example, the uptake of glucose by N. frontalis strain RE1 in the culture was reduced to 50% of the control value by monensin at 0.5 microgram/ml. In the presence of M. smithii strain PS, approximately three times as much monensin was needed to bring about the same effect. In similar tests, the sensitivity of strain RE1 to lasalocid was decreased about nine-fold in the presence of M. smithii. The effect was not observed if the methanogens were killed by autoclaving before inoculation. It is suggested that the enhanced resistance to ionophores in the presence of M. smithii is a consequence of changes in the energy metabolism of the fungi growing in co-culture.

Effect of the novel ionophore tetronasin (ICI 139603) on ruminal microorganisms

The antimicrobial activity of the novel ionophore tetronasin (formerly ICI 139603) was compared with that of monensin for the growth of ruminal bacteria, protozoa, and an anaerobic fungus. The potency of tetronasin toward most bacteria and the fungus was an order of magnitude or more greater than that of monensin. Lactobacillus casei was 55 times more sensitive to tetronasin than to monensin, indicating a potential role for tetronasin in reversing lactic acidosis. Bacteria with a gram-positive ultrastructure were generally sensitive to the ionophores and unable to adapt to grow in their presence. The exception was the cellulolytic Ruminococcus flavefaciens, which adapted during successive cultivation on media with increasing ionophore concentrations to grow at 100-fold higher concentrations of tetronasin than were initially lethal to the organism. Gram-negative bacteria were more resistant and generally able to adapt to grow in the presence of both ionophores. An in vivo trial with cattle and in vitro growth experiments indicated that the effect of tetronasin on ciliate protozoa was minor. In vitro experiments measuring hydrogen production by Neocallimastix frontalis suggested that this fungus would be unable to survive in ruminants receiving tetronasin.

Relating Landsat digital count values to ground reflectance for optically thin atmospheric conditions

The data from seven separate investigations that relate corrected Landsat digital count (DCc) values to ground-measured bidirectional reflectance R were summarized and examined as a single data set. As shown in the results these seven different sources of data were in significant agreement in estimating R from DCc. Thus a simplified linear formulation was derived for estimating R (0-100%) from Landsat DCc for conditions that approximate optically thin atmospheres. The relations are R4 = -5.9 + 0.476DCc4, R5 = -1 94 + 0.373DCc5, R6 = -1.40 + 0.412DCc6, and R7 = -0.49 + 1.220DCc7. The original Landsat digital count (DCo) data were corrected to a sun zenith angle of 39 degrees and for the 1/22/75-7/15/75 Landsat-2 calibration period to determine DCc.

Measurement of reflectance factors under daily and intermittent irradiance variations

A technique for measuring reflectance factors in diurnal and intermittent cloud insolation conditions using hand-held radiometers has been developed. Simultaneously collected reference panel and total insolation measurements were obtained during the South Texas summer growing season (April and May 1980) at Weslaco, Tex., using the GSFC MARK2 three-band hand-held radiometer. The estimated reflectance factors of four reference panels using the hand-held radiometer agreed closely with the expected reflectance as measured with a laboratory spectrophotometer over a wide range of insolation readings (from 20 to 91 mW/cm(2)). These results indicate that this technique could prove useful for achieving uniform reflectance factor measurements for remote sensing studies.

Procedures and equipment for the production and rearing of gnotobiotic lambs

38 gnotobiotic lambs have been derived by hysterectomy and reared for up to 7 months as true ruminants. 10 cases of contamination have occurred, 4 of which were attributable to a breach in the protective barrier and 1 to a contaminated food pack. The technique permits the use of liquid and solid foods and the regular taking of rumen and other samples, and also regular removal of all excreta and the cleaning of lambs and cages.

Cerebrocortical necrosis in ruminants: effect of thiaminase type 1-producing Clostridium sporogenes in lambs

Large numbers of orally inoculated thiaminase type 1-producing Clostridium sporogenes failed to establish in the alimentary tract of two conventionally born lambs. Conversely, when similar inoculations were given to two gnotobiotic lambs, large populations of Cl sporogenes established in their rumens and correspondingly high levels of thiaminase were produced. No clinical symptoms of thiamine deficiency or cerebrocortical necrosis were seen despite the presence of high levels of thiaminase in the rumen of one of the gnotobiotic lambs for a period of 86 days.