Randomized prospective comparison of laparoscopic and open peritoneal dialysis catheter insertion.

OBJECTIVE: To compare laparoscopic and conventional peritoneal dialysis catheter insertion with respect to post operative discomfort, complication rates, and catheter survival. DESIGN: Randomized prospective study. SETTING: Tertiary referral renal unit. PATIENTS: Fifty patients commencing peritoneal dialysis. INTERVENTION: Catheters were implanted laparoscopically or by a conventional surgical technique. MAIN OUTCOME MEASURES: The duration of surgery, hospital stay, pain scores, and analgesic requirements were recorded. Complications (early/late) and catheter survival were compared. RESULTS: The conventional procedure was faster than the laparoscopic (14.3 vs 21.9 minutes, p < 0.0001). There was no difference in any other parameter assessed. CONCLUSIONS: The data suggest that the insertion techniques are equivalent, and that laparoscopic insertion does not reduce early complication rates.

Physiological role of nitric oxide in regulation of renal function in humans.

The physiological role of endogenous nitric oxide in regulation of renal function in humans is unclear. Eight healthy men received an inhibitor of nitric oxide synthase, N(G)-monomethyl-L-arginine (L-NMMA, 3 mg/kg), and saline placebo intravenously on two occasions. L-NMMA significantly increased mean arterial pressure (+7%) and total peripheral resistance (+36%). However, because renal plasma flow did not decrease significantly, the increase in renal vascular resistance (+21%) was significantly less than the increase in total peripheral resistance. Glomerular filtration rate (-19%), filtration fraction (-10%), urine flow rate (-18%), sodium (-28%), and free water excretion (-25%) all decreased significantly. Fractional distal, but not proximal, sodium reabsorption increased. L-NMMA also significantly decreased plasma nitrate and urinary excretion of nitrate and dopamine. There were no significant changes in plasma renin activity, plasma endothelin, and aldosterone or in platelet number and ex vivo aggregation. L-NMMA had a plasma half-life of 75 min. Basal generation of nitric oxide appears to contribute less to vascular tone in the kidney than systemically but may alter afferent arteriolar tone. Decreased fractional sodium excretion supports an important physiological role for nitric oxide in inhibition of tubular sodium reabsorption, possibly mediated by the renal dopaminergic system.

Renal tubular responses to low-dose infusion of angiotensin II in type 1 diabetes mellitus; relation to chronic glycaemic control.

Renal responses to low-dose infusion of angiotensin II (ANGII, 1.25 and 2.5 ng.kg-1 min-1) were examined in 15 patients with type 1 diabetes and in 10 control subjects after pretreatment with lithium carbonate (750 mg, 20 mmol). Mean arterial pressure rose during ANGII infusion in both groups. The renal haemodynamic response to angiotensin II was not abnormal in the diabetic patients. Absolute proximal reabsorption of sodium was increased at baseline in the diabetic group, and fell during ANGII. Fractional lithium excretion was reduced in the diabetic patients at baseline (P < 0.05), and the fall in fractional lithium excretion during ANGII was less than in the control group (P = 0.012). In the diabetic group correlations existed between glycated haemoglobin and baseline glomerular filtration rate (P < 0.05), baseline fractional lithium excretion (P = 0.03), and the fall in fractional lithium excretion during angiotensin II infusion (P = 0.013). There was no correlation between glycated haemoglobin and absolute lithium clearance. Some indices of sodium reabsorption by the proximal renal tubule in diabetic patients correlate with prevailing chronic glycaemic control, largely reflecting changes in glomerular filtration rate. Reduced fractional proximal tubular responsiveness to exogenous angiotensin II is consistent with a role for endogenous angiotensin II as one mediator of increased tubular reabsorption of sodium in type 1 diabetes, but the data does not exclude alternative mechanisms.

Case report: infected false aneurysm at the site of an iliac stent.

False aneurysm formation at the site of iliac artery stent placement is an uncommon but serious complication of the procedure. We report a case of infected false aneurysm at the site of an iliac stent, complicated by renal failure.

Antinatriuretic action of insulin is preserved after angiotensin I converting enzyme inhibition in normal man.

To examine the potential role for intrarenal angiotensin II in mediating the antinatriuretic action of insulin, seven normal males were studied on three occasions, twice during euglycaemic hyperinsulinaemia (40 mU.m-2.min-1) after double-blind treatment for 1 week with placebo and the converting enzyme inhibitor perindopril, and on a time control day. Lithium carbonate 250 mg was given before each study as an indirect marker of tubular sodium handling. Renal haemodynamics did not change during hyperinsulinaemia. Insulin infusion reduced both the absolute and fractional urinary excretion rates of sodium (P < 0.001) and potassium (P < 0.001); these effects of insulin were not altered after converting enzyme inhibition. Lithium clearance did not change during insulin infusion on either day. The antinatriuretic effect of hyperinsulinaemia is mediated at a tubular site distal to the proximal tubule. The data does not support the hypothesis that intrarenal generation of angiotensin II plays a part in this action of insulin.

Urinary dopamine response to angiotensin II is not abnormal in type 1 (insulin-dependent) diabetes mellitus.

To examine the interaction between angiotensin II (ANGII) and dopamine in type 1 diabetes mellitus, urinary dopamine excretion was examined during ANGII infusion in 15 diabetic patients and 10 control subjects after pretreatment with lithium 750 mg and placebo. The antinatriuretic response and the urinary dopamine response to ANGII did not differ within or between the two groups on each study day. No correlation was observed between the decrements in urinary sodium excretion and urinary dopamine output during ANGII infusion in either group. The effect of insulin on urinary dopamine excretion was studied separately in seven non-diabetic subjects; sodium and potassium retention occurred during a hyperinsulinaemic euglycaemic clamp, but urinary dopamine did not change. The data suggest that the relationship between urinary sodium excretion and tubular dopamine synthesis remains normal in early type 1 diabetes mellitus both at baseline and during the antinatriuresis induced by angiotensin II. The cause of the reduction in urinary dopamine during ANGII infusion is unclear, but is probably not mediated directly by changes in proximal tubular sodium transport.

Lithium pretreatment affects renal and systemic responses to angiotensin II infusion in normal man.

1. Renal and systemic responses to infusion of angiotensin II (1.25 and 2.5 ng min-1 kg-1 body weight) were examined in ten normal males 12 h after single doses of 750 mg of lithium carbonate, 250 mg of lithium carbonate (n = 6) or placebo. 2. Baseline mean arterial pressure [mean (SEM)] was higher after 750 mg of lithium [93.1 (1.7) versus 89.5 (1.9 mmHg, P = 0.014], and the subsequent rise in blood pressure during angiotensin II infusion was lower [8.2 (1.8) versus 12.2 (2.4) mmHg, P less than 0.02]. 3. Lithium at a dose of 750 mg increased overnight urinary sodium excretion before the study. The fall in fractional sodium excretion during angiotensin II infusion was reduced after pretreatment with 750 mg of lithium [750 mg of lithium, 2.73 (0.24) to 1.34 (0.08)%; placebo, 2.69 (0.26) to 1.01 (0.11)%; P = 0.02]. The increases in effective filtration fraction [750 mg of lithium, 5.4 (1.0)%; placebo, 8.6 (0.7)%; P less than 0.05] and total effective renal vascular resistance [750 mg of lithium, 3700 (390) dyn s cm-5; placebo 5100 (460) dyn s cm-5; P = 0.03] during angiotensin II infusion were also attenuated after 750 mg of lithium. Responses after 250 mg of lithium did not differ from those after placebo. 4. The fall in plasma renin activity and the increase in plasma aldosterone concentration during angiotensin II infusion were similar on each study day. 5. Renal responses to exogenous angiotensin II are altered after pretreatment with a 750 mg dose of lithium in normal man. This dose of lithium is not an inert marker of sodium handling.

Renal responses to angiotensin II infusion in early type 1 (insulin-dependent) diabetes.

The renal response to infusion of sub-pressor doses of angiotension II was examined in nine euglycaemic Type 1 (insulin-dependent) diabetic patients with diabetes of short duration and nine non-diabetic control subjects. Plasma concentrations of angiotensin II and of free insulin were similar in both groups at baseline and during angiotensin II infusion. Glomerular filtration rate (Inutest clearance) fell to a similar extent during angiotensin II infusion in both groups (diabetic 116(SE 5) to 102(5) ml min-1 1.73-m-2; control 113(6) to 100(5) ml min-1 1.73-m-2). There was a large dose-dependent fall in effective renal plasma flow (p-aminohippurate clearance) during angiotensin II infusion which was of similar magnitude in both groups (diabetic; 694(46) to 521(21) ml min-1 1.73-m-2; control 665(41) to 498(30) ml min-1 1.73-m-2). The absolute and the fractional rates of urinary excretion of sodium were both lower in the diabetic group throughout the study, but there was a comparable antinatriuretic response to angiotensin II. Thus, the renal haemodynamic response to angiotensin II infusion is normal in early well-controlled Type 1 diabetes. Differences were found in the renal handling of sodium, which could not be related to altered renal tubular responses to angiotensin II or to peripheral hyperinsulinaemia.

Oral carbidopa has no effect on the renal response to angiotensin II in normal man.

1. The effect of inhibition of intrarenal dopamine synthesis by carbidopa on the renal response to angiotensin II infusion was studied in six healthy salt-loaded volunteers. 2. Subjects received an infusion of angiotensin II at two doses (0.5 and 1.0 ng min-1 kg-1) on two occasions. Before one study they took a single dose of carbidopa (100 mg) by mouth. 3. The plasma concentrations of angiotensin II produced by the infusion were similar on both study days. Angiotensin II infusion reduced urinary dopamine excretion on the control day. Urinary dopamine excretion was undetectable at all times after carbidopa, but carbidopa did not change the basal excretion rate of sodium. Despite inhibition of renal dopamine synthesis, the reductions in both absolute and fractional sodium excretion during the angiotensin II infusion were not different from those seen in the control study. 4. The reductions in glomerular filtration rate and effective renal plasma flow which occurred during angiotensin II infusion were not modified by pretreatment with carbidopa. 5. The renal response to angiotensin II is not modulated either wholly or in part by endogenous intrarenal dopamine levels. The fall in urinary dopamine excretion which occurs during angiotensin II infusion is consistent with a modulatory role for tubular reabsorptive capacity in the regulation of proximal tubular dopamine synthesis.

Association between connective tissue changes and smoking habit in type 2 diabetes and in non-diabetic humans.

Two hundred type 2 (non-insulin-dependent) diabetic patients and 170 non-diabetic age- and sex-matched normotensive controls were examined for limited joint mobility (LJM) and Dupuytren's contracture (DC), and their smoking history was documented. The prevalences of LJM and DC were not significantly different in diabetic and control subjects (LJM: odds ratio 1.58, 95% CI 0.99 to 2.50; DC: odds ratio 1.34, CI 0.81 to 2.23). Cigarette smoking was positively associated with both LJM and DC in the diabetic patients (LJM: relative risk (R) = 1.96, 95% CI 1.10 to 3.49; DC: R = 2.88, CI 1.29 to 6.43) and in the control group (LJM: R = 2.22, CI 1.70 to 5.86; DC: R = 2.71, CI 1.23 to 5.89). Limited joint mobility and Dupuytren's contracture are both associated with cigarette smoking in type 2 diabetic patients and in age-matched non-diabetic subjects. This suggests that type 2 diabetes is only one of a number of factors which promote the development of these connective tissue changes.

Unawareness of hypoglycaemia in insulin-treated diabetic patients: prevalence and relationship to autonomic neuropathy.

Three-hundred and two insulin-treated diabetic patients were questioned about hypoglycaemia using a structured questionnaire interview. Two-hundred and twenty-six patients (75%) had normal symptomatic awareness, 48 (16%) had partial awareness, 21 (7%) had absent awareness of hypoglycaemia, and 7 (2%) denied ever experiencing hypoglycaemia. Patients with complete loss of awareness of hypoglycaemia had diabetes of longer duration; none had a HbA1 concentration within the non-diabetic range. Loss of awareness of hypoglycaemia was associated with an increased incidence of severe hypoglycaemia, 19 (91%) of the patients with absent awareness, and 33 (69%) with partial awareness of hypoglycaemia experiencing severe hypoglycaemia over 1 year compared with only 41 (18%) of patients with normal awareness of hypoglycaemia (p less than 0.001). Cardiovascular autonomic function tests were performed in 226 (75% of the whole group). Of the patients who had diabetes for more than 15 years, 54% (n = 39) with normal awareness of hypoglycaemia, compared with 59% (n = 10) with absent awareness of hypoglycaemia, had evidence of cardiovascular autonomic impairment (NS). Seven (41%) of the 17 patients with absent awareness of hypoglycaemia and diabetes of greater than 15 years duration had no evidence of autonomic dysfunction. Loss of hypoglycaemia awareness is a common problem in patients with insulin-treated diabetes of long duration, is associated with an increased incidence of severe hypoglycaemia, but is not invariably associated with abnormal cardiovascular autonomic function tests.

Dissociation between the secretion and renal action of endogenous atrial natriuretic peptide in the syndrome of inappropriate antidiuresis.

A patient is described with the syndrome of inappropriate antidiuresis (SIAD) and renal sodium retention secondary to a lymphoma. The basal atrial natriuretic peptide (ANP) level and the ANP response to volume expansion were normal (age adjusted) but the natriuretic effect of ANP was attenuated by an unidentified factor. The case emphasizes the dominance of circulating volume over plasma tonicity in the regulation of ANP secretion.

Symptomatic awareness of hypoglycaemia: does it change on transfer from animal to human insulin?

A retrospective survey of symptomatic awareness of hypoglycaemia was performed in 189 randomly selected patients with insulin-treated diabetes who had been transferred from highly purified animal insulins to human insulin in the preceding 24 months. Of the 189 patients 44 (23%) complained of chronic hypoglycaemic unawareness, unrelated to ambient blood glucose control, before change of insulin species. Only 12 of the remaining 145 patients reported a reduction in awareness of hypoglycaemia following transfer to human insulin (6% of the whole group), while 6 (3%) reported an increase in awareness following the transfer. The 12 patients reporting reduced awareness had a mean duration of diabetes of 24 +/ 10 years compared to a duration of 15 +/- 10 years in the patients with normal awareness. The mean glycosylated haemoglobin concentrations were similar in all of the groups of patients. Six patients had developed total loss of awareness of the onset of hypoglycaemia, with all but one patient having suffered multiple episodes of severe hypoglycaemia. This reduced hypoglycaemic awareness on human insulin therapy was not associated with any significant improvement in blood glucose control.

Type 1 diabetes and driving experience: an eight-year cohort study.

The driving habits of 250 drivers with Type 1 diabetes were reviewed 8 years after a previous assessment. At least 45 patients had died and 18 patients could not be traced. A postal questionnaire of the 187 survivors elicited a response from 89%. Fifty-six patients (34%) still held an unrestricted driving licence, demonstrating that a significant proportion of diabetic drivers had not declared diabetes to the licensing authority and/or their motor insurer and continued to ignore the statutory regulations. Fewer patients held Heavy Goods Vehicle licences than 8 years previously. Twenty-four patients had ceased driving as their driving skills had diminished with advancing age and ill health. This was a voluntary decision by all but two patients whose driving licences had been revoked. Thirty-nine patients admitted to a total of 55 road traffic accidents since 1979; 9 accidents (16%) were attributed to hypoglycaemia. Although dependent on patients' honesty and the accuracy of recall, the disclosed accident rates of 4.9 per million miles driven for male drivers and 6.3 per million miles for female drivers are comparable to the accident rate of a non-diabetic driving population of similar age.

Limited joint mobility, Dupuytren's contracture and retinopathy in type 1 diabetes: association with cigarette smoking.

To examine the associations between cigarette smoking, connective tissue changes, and diabetic retinopathy, a detailed smoking history was elicited from 150 normotensive non-diabetic subjects, and from 266 randomly selected adult patients with Type 1 diabetes, after examination for limited joint mobility, Dupuytren's contracture, and diabetic retinopathy. Mean insulin dose and current glycosylated haemoglobin concentrations were comparable in diabetic smokers and non-smokers. The historical duration of smoking correlated with the duration of diabetes (r = 0.72, p less than 0.001). In diabetic patients limited joint mobility was positively associated with retinopathy, being found in 73/147 (50%) patients with retinopathy compared with 20/114 (18%) without retinopathy (chi 2 = 28.9, p less than 0.001), and also with Dupuytren's contracture, 19/34 (56%) of patients with limited joint mobility having Dupuytren's contracture, compared with 76/232 (33%) of patients without Dupuytren's contracture (chi 2 = 7.05, p less than 0.01). Limited joint mobility was observed in 50% of diabetic smokers compared with 25% of non-smokers (odds ratio = 2.87 (corrected for diabetes duration), 95% confidence interval 1.64-5.01). Diabetic retinopathy was weakly associated with smoking (odds ratio 1.09; 95% confidence interval 0.60-1.96). There was however an increased prevalence of background retinopathy among male smokers (50% vs 29%; chi 2 = 6.88, p less than 0.01). In non-diabetic males limited joint mobility was observed in 37% of smokers but only in 11% of non-smokers (NS), while 33% of smokers and 8% of non-smokers had Dupuytren's contracture (p = 0.012). These results suggest that cigarette smoking contributes to the development of extra-articular connective tissue changes in both diabetic patients and non-diabetic subjects, and possibly to the development of diabetic retinopathy.