Visit patterns at primary care centres and individual blood pressure level - a cross-sectional study.

OBJECTIVE: Hypertension is a major cause of cardiovascular disease. Nevertheless, blood pressure (BP) is often inadequately treated. We studied visit patterns at primary health care centres (PHCCs) and their relation to individual BP control. DESIGN AND SETTING: Cross-sectional register-based study on all patients with hypertension who visited 188 PHCCs in a Swedish region. PATIENTS: A total of 88,945 patients with uncomplicated hypertension age 40-79. MAIN OUTCOME MEASURES: Odds ratio (OR) for the individual patient to achieve the BP target of ≤140/90 mmHg. RESULTS: Overall, 63% of patients had BP ≤ 140/90 mmHg (48% BP < 140/90). The PHCC that the patient was enrolled at and, as part of that, more nurse visits at PHCC level was associated with BP control, adjusted OR 1,10 (95% CI 1.01 to 1.21). Patients visiting PHCCs with the highest proportion of visits with nurses had an even higher chance of achieving the BP target, OR 1.19 (95% CI 1.07 to 1.32). CONCLUSIONS: In a Swedish population of patients with hypertension, about half do not achieve recommended treatment goals. Organisation of PHCC and team care are known as factors influencing BP control. Our results suggests that a larger focus on PHCC organisation including nurse based care could improve hypertension care.

Pay for performance associated with increased volume of medication reviews but not with less inappropriate use of medications among the elderly - an observational study.

OBJECTIVE: A pay for performance programme was introduced in 2009 by a Swedish county with 1.6 million inhabitants. A process measure with payment linked to coding for medication reviews among the elderly was adopted. We assessed the association with inappropriate medication for five years after baseline. DESIGN AND SETTING: Observational study that compared medication for elderly patients enrolled at primary care units that coded for a high or low volume of medication reviews. PATIENTS: 144,222 individuals at 196 primary care centres, age 75 or older. MAIN OUTCOME MEASURES: Percentage of patients receiving inappropriate drugs or polypharmacy during five years at primary care units with various levels of reported medication reviews. RESULTS: The proportion of patients with a registered medication review had increased from 3.2% to 44.1% after five years. The high-coding units performed better for most indicators but had already done so at baseline. Primary care units with the lowest payment for coding for medication reviews improved just as well in terms of inappropriate drugs as units with the highest payment - from 13.0 to 8.5%, compared to 11.6 to 7.4% and from 13.6 to 7.2% vs 11.8 to 6.5% for polypharmacy. CONCLUSIONS: Payment linked to coding for medication reviews was associated with an increase in the percentage of patients for whom a medication review had been registered. However, the impact of payment on quality improvement is uncertain, given that units with the lowest payment for medication reviews improved equally well as units with the highest payment.

Randomised clinical trial: mesalazine versus placebo in the prevention of diverticulitis recurrence.

BACKGROUND: Previous studies have reached conflicting conclusions regarding the efficacy of mesalazine in the prevention of recurrent diverticulitis. AIM: To investigate the efficacy and safety of mesalazine granules in the prevention of recurrence of diverticulitis after acute uncomplicated diverticulitis. METHODS: Two phase 3, randomised, placebo-controlled, double-blind multicentre trials (SAG-37 and SAG-51) investigated mesalazine granules in patients with prior episodes (<6 months) of uncomplicated left-sided diverticulitis. Patients were randomised to receive either 3 g mesalazine once daily or placebo (SAG-37, n=345) or to receive either 1.5 g mesalazine once daily, 3 g once daily or placebo for 96 weeks (SAG-51, n=330). The primary endpoint was the proportion of recurrence-free patients during 48 weeks (SAG-37 and SAG-51) or 96 weeks (SAG-51) of treatment. RESULTS: Mesalazine did not increase the proportion of recurrence-free patients over 48 or 96 weeks compared to placebo. In SAG-37, the proportion of recurrence-free patients during 48 weeks was 67.9% with mesalazine and 74.4% with placebo (P=.226). In SAG-51, the proportion of recurrence-free patients over 48 weeks was 46.0% with 1.5 g mesalazine, 52.0% with 3 g mesalazine and 58.0% with placebo (P=.860 for 3 g mesalazine vs placebo) and over 96 weeks 6.9%, 9.8% and 23.1% respectively (P=.980 for 3 g mesalazine vs placebo). Patients with only one diverticulitis episode in the year prior to study entry had a lower recurrence risk compared to >1 episode. Safety data revealed no new adverse events. CONCLUSION: Mesalazine was not superior to placebo in preventing recurrence of diverticulitis.

Short-term effects of a pay-for-performance programme for diabetes in a primary care setting: an observational study.

OBJECTIVE: A pay-for-performance (P4P) programme for primary care was introduced in 2011 by a Swedish county (with 1.6 million inhabitants). Effects on register entry practice and comparability of data for patients with diabetes mellitus were assessed. DESIGN AND SETTING: Observational study analysing short-term outcomes before and after introduction of a P4P programme in the study county as compared with a reference county. SUBJECTS: A total of 84 053 patients reported to the National Diabetes Register by 349 primary care units. MAIN OUTCOME MEASURES: Completeness of data, level and target achievement of glycated haemoglobin (HbA1c), blood pressure (BP), and LDL cholesterol (LDL). RESULTS: In the study county, newly recruited patients who were entered during the incentive programme were less well controlled than existing patients in the register - they had higher HbA1c (54.9 [54.5-55.4] vs. 53.7 [53.6-53.9] mmol/mol), BP, and LDL. The percentage of patients with entry of BP, HbA1c, LDL, albuminuria, and smoking increased in the study county but not in the reference county (+26.3% vs -1.5%). In the study county, with an incentive for BP < 130/80 mmHg, BP data entry behaviour was altered with an increased preference for sub-target BP values and a decline in zero end-digit readings (38.3% vs. 33.7%, p < 0.001). CONCLUSION: P4P led to increased register entry, increased completeness of data, and altered BP entry behaviour. Analysis of newly added patients and data shows that missing patients and data can cause performance to be overestimated. Potential effects on reporting quality should be considered when designing payment programmes. Key points A pay-for-performance programme, with a focus on data entry, was introduced in a primary care region in Sweden. Register data entry in the National Diabetes Register increased and registration behaviour was altered, especially for blood pressure. Newly entered patients and data during the incentive programme were less well controlled. Missing data in a quality register can cause performance to be overestimated.

Serum cytokine pattern in young children with screening detected coeliac disease.

Coeliac disease is an autoimmune disease characterized by inflammation localized to the small bowel, but less is known about systemic signs of inflammation. The aim was to measure cytokines of the T helper 1 (Th1) and T helper 2 (Th2) cell patterns in children with screening-detected coeliac disease before and after treatment with a gluten-free diet. Serum samples selected before and after the start of a gluten-free diet from 26 3-year-old children diagnosed with biopsy-proven coeliac disease and from 52 matched controls were assayed in an multiplex enzyme-linked immunosorbent assay (ELISA) for the 10 cytokines: interferon (IFN)-γ, interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-8, IL-10, IL-12p70, IL-13 and tumour necrosis factor (TNF)-α. Among Th1 cytokines, IFN-γ and IL-12p70 were elevated significantly in children with coeliac disease compared to controls (P < 0.001 and P = 0.001, respectively). Similar findings were demonstrated for the Th2 cytokines IL-5 (P < 0.001), IL-10 (P = 0.001) and IL-13 (P = 0.002). No difference in cytokine levels between the two groups was found for TNF-α, IL-1ß, IL-2, IL-4 and IL-8. After gluten-free diet, levels of IL-5, IL-12 and IL-10 decreased significantly (P < 0.001, P = 0.002 and P = 0.007) and IFN-γ levels were reduced (P = 0.059). Young children with coeliac disease detected by screening demonstrate elevated levels of serum cytokines at time of diagnosis. A prolonged systemic inflammation may, in turn, contribute to long-term complications known to be associated with untreated coeliac disease.

Inguinal hernia repair using a synthetic long-term resorbable mesh: results from a 3-year prospective safety and performance study.

PURPOSE: Conventional meshes for hernia repair and abdominal wall reinforcement are usually made from polypropylene, polyester or other synthetic plastic materials known to promote foreign body reactions and a state of chronic inflammation that may lead to long-term complications. A novel approach is to use long-term resorbable implants like TIGR(®) Matrix Surgical Mesh. Preclinical studies have shown that this mesh maintains mechanical integrity beyond the point in time where newly formed tissue is capable of carrying the abdominal loads. METHODS: This was a first-in-man, prospective, pilot study performed during 2009, at two sites in Sweden. Forty patients with primary inguinal hernias were enrolled for Lichtenstein repair using TIGR(®) Matrix Surgical Mesh. The primary endpoint was safety as assessed by monitoring the incidence of adverse events and serious adverse events (SAEs) both related and unrelated to the mesh. The secondary endpoint was pain or discomfort. Visual Analogue Scale (VAS) 0-10 and Inguinal Pain Questionnaire were used for scoring pain and discomfort. Included patients have been followed for 36 months using ultrasound in combination with clinical examination. RESULTS: All patients followed a normal early postoperative course. After 12 months no SAEs were reported. None of the patients with an isolated lateral inguinal hernia (LIH) had developed a recurrence but 4 (44 %) with medial and 4 (33 %) with combined hernias had recurred at 36-month follow-up. After 3-year follow-up none of the patients with LIH reported pain in the VAS-form and none of those patients could feel the sensation of a mesh in their groin. In the total study population 5 (16 %) patients experienced chronic pain in the form of mild sporadic pain and 3 (9.7 %) patients could feel the sensation of a mesh in their groin. CONCLUSION: The use of a synthetic long-term resorbable mesh (TIGR(®) Matrix Surgical Mesh) in Lichtenstein repair was found to be safe, without recurrences, and promising regarding pain/discomfort at 3-year follow-up in patients with LIH. However, patients with medial and combined inguinal hernias had high recurrence rates.

Prolene Hernia System, Lichtenstein mesh and plug-and-patch for primary inguinal hernia repair: 3-year outcome of a prospective randomised controlled trial. The BOOP study: bi-layer and connector, on-lay, and on-lay with plug for inguinal hernia repair.

BACKGROUND: Dissection requirements differ between various methods for inguinal hernia repair, which may affect operation times, pain response and possibly recovery time. The objectives of this study were to establish if any differences concerning these aspects could be detected following three principally different techniques for primary inguinal hernia repair. METHODS: A total of 472 men between 30 and 75 years of age with primary inguinal hernias were included in a prospective controlled study and randomised to Lichtenstein mesh (L), PerFix Plug (P) or the Prolene Hernia System (PHS) procedure. All patients were seen and data were collected after 2 weeks, 3 months, 1 year and 3 years. RESULTS: The follow-up rates were 100, 99.8, 98.7 and 95.3%, respectively. The mean operation time was shorter for P (35.5 min, P < 0.001) and PHS (37.4 min, P < 0.02) versus L (40.4 min). More than 85% of the procedures were performed under local anaesthesia. There were no statistically significant differences between the groups concerning early or late complications, return to full functional ability, early pain response, analgesic consumption or the studied late-outcome parameters after 3 years of observation. Seven (1.5%) evenly distributed recurrences were registered. CONCLUSION: All of the techniques are suitable for operation under local anaesthesia. The PHS and P techniques can be performed with shorter operation times than the L method. Early and late outcomes are, however, comparable, with no significant differences concerning complication rates, return to full functional status and/or pain response.

Food induced stimulation of the antisecretory factor can improve symptoms in human inflammatory bowel disease: a study of a concept.

BACKGROUND: Antisecretory factor (AF), a 41 kDa cloned and sequenced protein, suppresses intestinal inflammation and hypersecretion in animals. Endogenous AF production can be induced by dietary modifications in several animal species, and this feed has been shown to reduce the incidence of diarrhoeal disease in weaning piglets. The role of AF in intestinal disease in humans is not known. AIMS: To study the effects of hydrothermally processed cereals, optimised for AF induction in animals, added to the diet of patients with longstanding symptoms of inflammatory bowel disease (IBD). PATIENTS: Fifty three patients with IBD (ulcerative colitis and Crohn's disease) were entered into the study, and 50 completed follow up. The experimental group consisted of 16 females (mean age 50 (SEM 5) years) and 10 males (41 (4) years) and the placebo group of 12 women (41 (4) years old) and 12 men (51 (5) years). METHODS: Patients were randomised to receive either hydrothermally processed cereals (active treatment) or the same amount of ordinary cereals (placebo treatment) for four weeks in a double blind study design. Baseline diet and medications remained unchanged. Bowel symptoms, plasma levels of AF, and colonic biopsies were evaluated before and after treatment. RESULTS: The active treatment significantly improved subjective ratings of clinical symptoms and increased plasma AF levels compared with placebo. Plasma lipid levels were unaffected. CONCLUSION: Hydrothermally processed cereals can induce AF production in human IBD. This increase in endogenous AF activity is associated with clinical improvement. Further studies are warranted to clarify the exact role of AF in human intestinal disease.

[Early treatment can improve prognosis in diabetic nephropathy]. / Tidig behandling kan förbättra prognos vid diabetisk njursjukdom.

Prognosis in diabetic nephropathy has changed dramatically during the past decade, and slowing of the disease process has been made possible by intervention against specific risk factors. Nonetheless, diabetic nephropathy has become the leading cause of end stage renal disease. Early detection and prevention, or at least delaying, of disease progression have become crucial aims, and several treatment strategies designed to prevent end stage renal disease have recently been published. The common denominator of these strategies is screening for microalbuminuria in diabetic patients rather than awaiting the appearance of overt symptoms.

The effect of metabolic control on rate of decline in renal function in insulin-dependent diabetes mellitus with overt diabetic nephropathy.

BACKGROUND: Strict glycaemic control has been shown to reduce the risk of developing diabetic nephropathy. In established nephropathy, however, the impact of glycaemic control on prognosis is less clear. Therefore we investigated the effect of long-term glycaemic control on the decline in renal function in insulin-dependent diabetic patients with overt nephropathy. METHODS: The study was performed at two hospital-based diabetes centres in western Sweden. The study was an observational retrospective follow-up study in 158 insulin-dependent diabetics with proteinuria with a mean (+/-SD) age of 36+/-9 years and a diabetes duration of 22+/-8 years. The change in glomerular filtration rate was measured as 51Cr EDTA clearance for a median of 8 years (range 1-17). Glycaemic control was determined with measurements of glycated haemoglobin A1c. RESULTS: The decline in glomerular filtration rate was 3.8+/-3.7 ml/min/year. The blood pressure was 143/82+/-15/7 mmHg and the mean glycated haemoglobin was 8.7+/-1.6%. The correlation coefficient between glycated haemoglobin and decline in glomerular filtration rate was -0.39 (P<0.0001 ) and between decline in glomerular filtration rate and systolic and diastolic blood pressure -0.17 (P=0.03) and -0.29 (P=0.003) respectively. In patients with glycated haemoglobin <8.0% and diastolic blood pressure <85 mmHg the decline in glomerular filtration rate was 1.7+/-2.3 ml/min/year. CONCLUSIONS: In this retrospective observational study, effective blood-pressure control was associated with a low rate of decline in renal function and a low urinary albumin excretion. The correlation between glycaemic control and decline in renal function indicates that poor glycaemic control can accelerate the loss of renal function in diabetic nephropathy.

Enalapril versus metoprolol in primary hypertension--effects on the glomerular filtration rate.

BACKGROUND: Hypertension is a significant cause of end-stage renal failure and effective treatment of hypertensive will reduce the progression rate of chronic renal failure in various kidney disorders. Different classes of drugs may be more effective than others in this respect. In this study we compared the effects on the glomerular filtration rate (GFR) of the ACE-inhibitor enalapril and the betablocker metoprolol in patients with mild and moderate primary hypertension during 6 years. METHODS: Patients with GFR in the normal range (> or = 80 ml/min/1.73 m2 BSA) were included after a placebo treatment period of 4-8 weeks if diastolic blood pressure was 100-120 mm Hg. Target blood pressure was set to < 90 mm Hg diastolic. One hundred and thirty patients were randomized in an open parallel study to receive either enalapril or metoprolol. No placebo group was included. GFR was measured using the 51CR-EDTA clearance method and 81 patients completed the study. RESULTS: At inclusion, there were no significant differences regarding GFR or blood pressure between the groups. The blood pressure treatment goal was reached in all patients and was maintained during the whole observation period. A small but significant fall in GFR by 4 ml/min/1.73 m2 BSA was noted in both groups after the first year of treatment but thereafter GFR decreased by only 1 ml/min/year/1.73 m2 BSA, in both groups. Body weight, serum uric acid and triglycerides increased slightly with metoprolol treatment but no other differences between the two treatments were noted. CONCLUSIONS: With the blood pressure maintained at the same level using either enalapril or metoprolol during a 6-year study period, GFR decreased to the same extent in the two groups both during the first year and thereafter. The overall magnitude of the GFR decline approached that of the normal age-related decrease of kidney function, i.e. GFR decreased only about 1 ml/min/year. Thus, treatment with an ACE-inhibitor, enalapril, and a beta-blocker, metoprolol, protected the kidney function to the same extent in this 6 year long study in mild and moderate primary hypertension.

Renal disease and acid-suppressing drugs.

No comparative epidemiological data can be found in the literature on the renal safety of acid-suppressing drugs. We followed-up a cohort of close to 180,000 persons during periods of treatment and non-treatment with five anti-ulcer drugs to evaluate the risk of idiopathic acute renal failure and/or nephrotic syndrome. After reviewing medical records, five patients were found to be cases. Two presented with acute renal failure and three had nephrotic syndrome. Three cases occurred during periods of non-exposure to anti-ulcer drugs. Two cases occurred during current use of ranitidine: one of acute renal failure and one of nephrotic syndrome. No case was encountered during treatment with cimetidine, famotidine, nizatidine or omeprazole. The incidence of idiopathic renal disease in the general population was 1 per 100,000 person-years. The relative risk associated with use of acid-suppressing drugs was 1.8 (95% CI, 0.3-10.7) compared to non-use. These results do not suggest a major increased risk for acute renal injury and/or nephrotic syndrome associated with use of anti-ulcer drugs.

Influence of topical rectal application of drugs on dextran sulfate-induced colitis in rats.

A rat model of colitis [dextran sulfate (DSS)] was used to study the permeation of Evans blue (EB) from the lumen into the wall of proximal and distal colonic loops after exposure to the dye for 2 hr. Topical application of drugs used in human ulcerative colitis (lidocaine, mesalazine, prednisolone, or sucralfate) was given daily during induction of colitis to protect the mucosa. The mucosal changes were evaluated with special regard to peptidergic innervation [substance P (SP) and neuropeptide Y (NPY)], invasion of antigen-presenting polydendritic cells, and mucin-containing goblet cells. DSS-treatment caused a significantly increased permeation of EB. In the proximal loops a significant inhibition was obtained after treatment with lidocaine, prednisolone, or sucralfate. In the distal loops only treatment with lidocaine had a preventive effect. Immunocytochemically there was a clear hyperplasia of both mucosal SP- and NPY-immunoreactive nerve fibers in regions with crypt abnormalities. In these regions also most of the goblet cells were devoid of mucus. Like the changes in permeation, these morphological changes were most prominent in the distal loops. With induction of colitis, the mucosa and lamina propria were invaded by polydendritic cells; the visual score was markedly decreased in the proximal loops treated with lidocaine, prednisolone, or sucralfate. In the distal loops similar effects were obtained after treatment with lidocaine or prednisolone. Prevention of the influx of antigens in both loops after lidocaine treatment with reduced recruitment of polydendritic cells into the lamina propria is suggested. The nerve hyperplasia may thus be secondary to luminal challenge with antigens during induction of colitis. The discrepancy between increased permeation and absence of polydendritic cell response in the distal loops after prednisolone may reflect separate actions of steroids on the intestinal epithelium and the immune cells.

Deletion insertion polymorphism of the angiotensin converting enzyme gene and progression of diabetic nephropathy.

BACKGROUND: The activity in the renin angiotensin system is important for the progression of diabetic nephropathy. Genetic abnormalities in this system have been suggested as a risk factor for the development and progression of diabetic nephropathy. The homozygous DD (deletion) genotype of the angiotensin-converting enzyme gene has been associated with increased circulating angiotensin converting enzyme and a more rapid progression of IgA nephritis. The aim of the present study was to investigate the relationship between the DD genotype and rate of decline in kidney function in patients with type 1 diabetes and nephropathy in relation to other risk factors for loss of renal function. METHODS: The insertion-deletion polymorphism was determined in patients with type 1 diabetes mellitus and diabetic nephropathy. Retrospective data were collected in 86 patients. The patients were studied by determining glomerular filtration rate during a mean (+/-SD) of 8.5 +/- 4.0 years (range 1.3-14.5 years) using the clearance of 51Cr EDTA. Measurements for glycaemic control, urinary albumin excretion, blood pressure, and serum lipids were available for the study period. RESULTS: The mean decline in glomerular filtration rate was 3.2 +/- 3.6 ml/min/year in all patients. Patients with the DD, ID and II genotype showed a rate of change in glomerular filtration of -3.5 +/- 3.5, -3.1 +/- 4.4 and -2.6 +/- 2.3 ml/min/year respectively. The tendency towards a more rapid decline in kidney function in the DD genotype was nonsignificant. The decline in renal function was significantly correlated to systolic and diastolic blood pressure, Hb AIc and serum triglycerides. Serum cholesterol was nearly significantly correlated to the decline in glomerular filtration rate (P = 0.057). Of these variables, glycaemic control and blood pressure control remained significant in multivariate analysis (P = 0.02 and P = 0.04, respectively). The patients with the DD genotype weighted significantly less. The body weight in patients with the DD genotype was 67.1 +/- 11.4 kg vs 74.9 +/- 9.2 kg in patients with the II genotype (P = 0.018). CONCLUSION: In this study, poor glycaemic and blood pressure control were associated with a more rapid loss of renal function in diabetic nephropathy while polymorphism of the angiotensin converting enzyme gene was not.

Synchronized Terrestrial-Atmospheric Deglacial Records Around the North Atlantic

On the basis of synchronization of three carbon-14 (14C)-dated lacustrine sequences from Sweden with tree ring and ice core records, the absolute age of the Younger Dryas-Preboreal climatic shift was determined to be 11,450 to 11,390 +/- 80 years before the present. A 150-year-long cooling in the early Preboreal, associated with rising Delta14C values, is evident in all records and indicates an ocean ventilation change. This cooling is similar to earlier deglacial coolings, and box-model calculations suggest that they all may have been the result of increased freshwater forcing that inhibited the strength of the North Atlantic heat conveyor, although the Younger Dryas may have begun as an anomalous meltwater event.

Physiological and histological characterisation of a pig kidney in vitro perfusion model for xenotransplantation studies.

A pig kidney perfusion model aimed for use in immunological and physiological xenotransplantation research has been developed. Organ viability was characterised by clearance studies, functional response to hormones/diureticum and by light microscopical examination. The pig kidney was perfused in a specially designed plexiglass chamber, using a roller pump and a small membrane oxygenator (O2/CO2, 95/5). The recirculating perfusate used was autologous pig blood diluted by Tyrodes solution to a hematocrit of 30%, at a total starting volume of 600-650 ml. The temperature was 37 degrees C. It was crucial for good organ function that the nephrectomy operating time, as well as the warm (1-2 min) and cold ischemia (average 43 min) times were minimized. The average total perfusion time was 151 minutes. Physiological parameters were measured during 10-15 minute periods at average times of 40, 63, 88 and 142 minutes. The clearance values of inulin in these periods were 54 +/- 13, 59 +/- 15, 48 +/- 23, 27 +/- 5 and for PAH; 103 +/- 14, 121 +/- 14, 106 +/- 30, 114 +/- 34 ml/min/100 g tissue weight. The plasma flows were 123 +/- 12, 155 +/- 17, 136 +/- 36 and 206 +/- 57 ml/min/100 g. The injection of 0.5 micrograms of alpha ANP to the perfusate resulted in a significant decrease in vascular resistance, and increase in urine production (+107%), as well as sodium (+112%) and potassium (+46%) excretion. Ten mg furosemide doubled the urine production and sodium excretion, while potassium excretion increased marginally. The number of leucocytes decreased by 39% during the perfusion, while the platelet count was unaffected. Light microscopy of the renal tissue after termination of the experiments revealed endothelial damage to variable extent. Loss of endothelial cells was most obvious at the level of arcuate and interlobular arteries, while the endothelium was intact in larger arteries and veins. Accumulation of polymorphonuclear granulocytes was found predominantly in the peritubular vessels, and to a lesser degree in the cortical venules. In the tubular cells, only minimal epithelial swelling and irregular cytoplasmic vacuolisation was found. Thus, a good functional viability can be maintained during 2 hours in vitro perfusion, although a decline in function as well as structural damage can be seen at the end of the experiment.

Extracorporeal ("ex vivo") connection of pig kidneys to humans. I. Clinical data and studies of platelet destruction.

The pioneering experiment by Welsh et al. (Immunological Lett 1991:29:167-170) connecting a pig kidney to the human circulation has been repeated in a modified manner. Two volunteer dialysis patients were pretreated by daily plasmapheresis on days -2,-1, and 0 to remove the naturally occurring anti-pig xenoantibodies. The anti-pig lymphocytotoxic liters were reduced from 1:8 to 1:2 in patient 1 and from 1:8 to 1:1 in patient 2. No steroids or immunosuppressive drugs were administrated before or during the experiments. A sterile pig kidney was extracorporeally ("ex vivo") connected to the patients a/v fistula using an arterial and a venous pump similar to a dialysis. The two experiments gave different results. In the first experiment the perfusion pressure was kept at 100 mmHg for the initial 25 min by reducing the pump speed until the minimum blood flow of 30 ml/min was reached. Thereafter, the pressure rose continuously and the experiment was terminated at 65 min at a perfusion pressure of 200 mmHg. The patient did not feel any discomfort during the perfusion. In the second experiment, a stable blood flow of 200 ml/min was reached at a pressure of 100 mmHg after a few minutes. The perfusion was terminated at 15 min when the patient developed chest and abdominal pain, hypotension, and electrocardiographic signs of myocardial ischemia. The patient recovered quickly. In the first experiment, small volumes of clear urine was produced until the pressure rose above 100 mmHg, which resulted in hematuria. In the second experiment clear urine (4 ml/min) was produced. (51)Chromium clearance values were after 15 min <1 ml/min for kidney 1 and 12 ml/min (8 ml/min/100 g) for kidney 2. A drastic reduction in platelet count (128 to 48 and 64 to 8 × 10(9)/1, respectively) during the passage through the kidney was found in blood samples collected simultaneously before and after the organ. No change in hemoglobin values and leucocyte counts were found. Light- and electron-microscopical analysis of the kidney tissues revealed for kidney 1 focal areas with obliteration of the glomerular and peritubular capillaries by platelets and PMN cells and severe damage of the endothelial cells comparable to a picture of a hyperacute rejection. In kidney 2, all vessels were patent but in the capillaries large amount of membrane fragments were detected by electron microscopy and a discrete damage of the endothelial cells were seen in some segments. No intact platelets were present in the vascular tree. These human experiments support the hypothesis that hyperacute rejection of pig to human xenografts is delayed in time by removal of the preformed anti-pig xenoantibodies. A new finding was a very rapid destruction of platelets occurring in the kidney of patient 2 who had very low liters of xenoantibodies. The humoral immune response is described in detail in an accompanying paper (Rydberg et al., this issue).

Extracorporeal ("ex vivo") connection of pig kidneys to humans. II. The anti-pig antibody response.

Pig kidneys were extracorporeally "ex vivo" connected to the circulation of two volunteer male dialysis patients (Breimer et al., this issue). The patients were pretreated by daily plasmapheresis for 3 consecutive days, which reduced the anti-pig lymphocytotoxic titer from 8 to 2 in the first patient and from 8 to 1 in the second patient. The anti-pig hemagglutinating titers were reduced from 32 to 4 in the first patient and from 2 to 1 in the second patient. No drugs, except heparin, were given. The perfusion lasted for 65 min in patient 1 and the experiment was terminated due to increased vascular resistance in the pig kidney. Ultrastructural investigation showed a picture similar to a hyperacute vascular rejection. Immunohistochemical studies showed a weak staining of IgM antibodies, but no IgG in the small arteries and glomeruli. The pig kidney of patient 2 was perfused for 15 min and the experiment terminated due to serious side effects of the patient. Light and electron microscopical investigation showed virtually no structural changes of the kidney tissue and immunostaining for human antibodies was negative. In both patients, serum samples collected 2-5 weeks postperfusion showed a strong anti-pig antibody titer rise (up to 512) which thereafter declined but stabilized on a higher level than before the experiment. The antibody response in the two patients was different. In patient 1, the major anti-pig antibodies directed to carbohydrate antigens were of IgG (IgG1 and IgG2 subclasses) type, while the IgM response was less prominent and virtually no IgA antibodies were produced. Despite the short duration of the perfusion in patient 2, a humoral immune response was seen that was mainly confined to the IgA immunoglobulin class (IgA1 subclass). Blood group glycospingolipid fractions, prepared from the contralateral kidney of the donor pigs, were used for immunostaining with patient serum samples. In both patients, the antibodies produced after the perfusion, mainly recognized the Galα1-3Gal epitope both as part of the "linear B" pentasaccharide but also on more complex carbohydrate structures. Patient 1 was HLA-immunized before the experiment due to a kidney allograft and had a panel reactivity of 85% before the perfusion. No change in the panel reactivity of HLA-antibodies was found after the perfusion experiments. Patient 2 had no HLA antibodies before and remained negative after the perfusion. Patient serum samples collected before and after the perfusion were tested for reactivity against human endothelial cell lines. No antibodies were generated.