Appetite stimulation with cannabis-based medicine and methods for assessment of glomerular filtration in older patients with medical illness: A study protocol

BACKGROUND AND AIM

Malnutrition in older patients is linked to poor appetite. Cannabis-based medicine may have orexigenic properties in older patients, but this has to our knowledge never been investigated. In older patients, uncertainty applies to the accuracy of estimated glomerular filtration rate (eGFR) based on creatinine, which is crucial for medication prescribing. In older patients with poor appetite, the study aims (1) to assess the efficacy of Sativex® (8.1-mg delta-9-tetrahydrocannabinol [THC] and 7.5-mg cannabidiol [CBD]) to stimulate appetite and (2) to compare the performance of various GFR-estimates and measured-GFR (mGFR) for determining gentamicin clearance utilizing population pharmacokinetic (popPK) modelling methods.

METHODS AND OBJECTIVES

This study is composed of two substudies. Substudy 1 is an investigator-initiated single-center, double-blinded, randomized, placebo-controlled, superiority, cross-over study. Substudy 1 will recruit 17 older patients with poor appetite, who will also be invited to substudy 2. Substudy 2 is a single-dose pharmacokinetics study and will recruit 55 patients. Participants will receive Sativex® and placebo in substudy 1 and gentamicin with simultaneous measurements of GFR in substudy 2. The primary endpoints are as follows: Substudy 1-the difference in energy intake between Sativex® and placebo conditions; substudy 2- the accuracy of different eGFR equations compared to mGFR. The secondary endpoints include safety parameters, changes in the appetite hormones, total ghrelin and GLP-1 and subjective appetite sensations, and the creation of popPK models of THC, CBD, and gentamicin.

Evaluating Commutability of Control Materials in Three Nordic External Quality Assessment Schemes for Lipoproteins

BACKGROUND

The quality of control materials is crucial for evaluating external quality assessment (EQA) results. To detect method differences, the EQA material should behave the same as a patient sample, meaning the material must be commutable. Noncommutable materials may cause misinterpretations of EQA results. Here, we examined the commutability of EQA materials used in 3 Nordic EQA schemes for lipids.

METHODS

The study was designed according to the procedures recommended for assessing commutability by the International Federation of Clinical Chemistry and Laboratory Medicine. Commutability was assessed based on the difference in bias between a control material (CM) and clinical samples (CS) consisting of human plasma using 2 different measurement procedures (MPs). Measurands: LDL-cholesterol (LDL-C), total cholesterol (TC), HDL-cholesterol (HDL-C), and triglycerides (TG). Four CMs (CM1-4) were assessed for commutability by using 40 CSs and 3 MPs (Abbott Architect, Roche Cobas, and Siemens Atellica).

RESULTS

Unmodified native CMs (CM1 and CM3), stored at -80 °C, were commutable for all included measurands, except for LDL-C that was indeterminate, when comparing MPs pairwise. Modified CM2 was noncommutable for HDL-C, LDL-C, non-HDL-C, and LDL-C calculations. Unmodified native CM4, stored at -20°C were noncommutable for LDL-C.

CONCLUSIONS

Unmodified serum samples stored at -80 °C were commutable for lipids on the evaluated MPs, and therefore suitable as CMs in EQA schemes. Moreover, the study demonstrated that minor modifications of samples may lead to noncommutability.

In-vivo validation of fast spectral velocity estimation techniques

Spectrograms in medical ultrasound are usually estimated with Welch's method (WM). WM is dependent on an observation window (OW) of up to 256 emissions per estimate to achieve sufficient spectral resolution and contrast. Two adaptive filterbank methods have been suggested to reduce the OW: Blood spectral Power Capon (BPC) and the Blood Amplitude and Phase EStimation method (BAPES). Ten volunteers were scanned over the carotid artery. From each data set, 28 spectrograms were produced by combining four approaches (WM with a Hanning window (W.HAN), WM with a boxcar window (W.BOX), BPC and BAPES) and seven OWs (128, 64, 32, 16, 8, 4, 2). The full-width-at-half-maximum (FWHM) and the ratio between main and side-lobe levels were calculated at end-diastole for each spectrogram. Furthermore, all 280 spectrograms were randomized and presented to nine radiologists for visual evaluation: useful/not useful. BAPES and BPC compared to WM had better resolution (lower FWHM) for all OW<128 while only BAPES compared to WM had improved contrast (higher ratio). According to the scores given by the radiologists, BAPES, BPC and W.HAN performed equally well (p>0.05) at OW 128 and 64, while W.BOX scored less (p<0.05). At OW 32, BAPES and BPC performed better than WM (p<0.0001) and BAPES was significantly superior to BPC at OW 16 (p=0.0002) and 8 (p<0.0001). BPC at OW 32 performed as well as BPC at OW 128 (p=0.29) and BAPES at OW 16 as BAPES at OW 128 (p=0.55). WM at OW 16 and 8 failed as all four methods at OW 4 and 2. The intra-observer variability tested for three radiologist showed on average good agreement (90%, kappa=0.79) and inter-observer variability showed moderate agreement (78%, kappa=0.56). The results indicated that BPC and BAPES had better resolution and BAPES better contrast than WM, and that OW can be reduced to 32 using BPC and 16 using BAPES without reducing the usefulness of the spectrogram. This could potentially increase the temporal resolution of the spectrogram or the frame-rate of the interleaved B-mode images.

The Nordic Trueness Project 2002: use of reference measurement procedure values in a general clinical chemistry survey

Up to 136 laboratories participated in a joint effort to assess the trueness of routine measurements for 14 serum components. An unmodified, fresh-frozen human serum ("IMEP-17 Material 1"), produced for an international inter-laboratory comparison, served as the "master material". The serum had assigned values of the highest available metrological quality, and is assumed to involve no or negligible commutability problems. The material was used in the assignment of traceable values to two other reference sera, "CAL" and "X", through parallel measurements on the three materials according to a common protocol. In this transfer process, uncertainty estimates were provided for all values. The material CAL had been supplied with reference measurement procedure values in 1997, and the two sets of assigned values agreed well. A lyophilized control serum "HK02" was also included in the routine analysis series. It, too, had assigned values based on reference measurement procedures. Significant matrix effects were found. The project has provided: Assigned traceable values for 14 components in a fresh-frozen serum, available to Nordic laboratories for the coming years as "NFKK reference serum X"; Confirmation of earlier assigned reference measurement procedure values for a number of components in CAL, the main calibrator in the Nordic Reference Interval project (NORIP). The transferred values will now serve as the primary reference.; Evidence of long-term stability ( > or = 5 years) of the fresh-frozen serum CAL when stored at -80 degrees C; Evidence of substantial matrix effects in the processed serum HK02. The findings should be used to discuss to what extent reference measurement procedure values are useful and cost-efficient for this type of material.

Minimally processed fresh frozen human reference sera: preparation, testing, and application to international external quality assurance

The preparation of unmodified or minimally processed fresh frozen human sera is described, as well as the previous use of such sera, e.g. in Nordic and international external quality assurance (EQA) activities. The unmodified serum is prepared from fresh donors' blood collected in dry bags and allowed to coagulate. The serum is collected "on the clot", pooled, filtered, mixed, dispensed in polypropylene vials and frozen at -80 degrees C without further processing. Some batches were slightly modified by spiking or dilution. Critical steps of the production and use of the sera are described and improvements are discussed. A total of 34 different batches have been prepared since 1985. Results from homogeneity and stability studies are presented. The studies cover 18 routine components in serum stored at +4 degrees C to 37 degrees C for up to 34 days. Good stability was observed for storage of all components, with the exception of triglyceride. Amylase, creatininium, glucose, gamma-glutamyltransferase, urate (and perhaps carbamide) showed deterioration after 13 days of incubation at 37 degrees C. The long-term stability at -80 degrees C is reviewed and new data are presented, e.g. as consensus values from EQA schemes, where the same serum has been sent out three times over 5 years, and from reference measurement procedure values that have been assigned twice with an interval of 5 years. Furthermore, a 10-year stability study has been started.

Night blood pressure and cigarette smoking: disparate association in healthy subjects and diabetic patients

Cigarette smoking and diabetes are well known risk factors for cardiovascular disease. The relation of nocturnal blood pressure (BP) to cigarette smoking is unclarified. We examined ambulatory BP in 18 healthy smokers matched for sex and age to 18 non-smokers. Sixteen smoking type 1 diabetic patients matching 16 non-smoking patients with normal urinary albumin excretion were also investigated. None of the healthy subjects or diabetic patients had a clinic BP > 160/95 mmHg. Night BP (systolic/diastolic mmHg) in healthy smokers (mean +/- SD) 102 +/- 9/57 +/- 5 was lower than in healthy non-smokers 108 +/- 10/61 +/- 6 (p = 0.06/p < 0.05). The difference between smokers and non-smokers was most prominent in the 3 h period just before rising (99 +/- 9/57 +/- 6 versus 108 +/- 8/62 +/- 7, p < 0.01/p < 0.05). Daytime BP was similar between groups. The night/day ratio (%) of systolic (84 +/- 7) and diastolic (74 +/- 7) BP in healthy smokers was lower than in non-smokers (88 +/- 5 versus 80 +/- 5, p < 0.05 and p < 0.01) indicating an altered diurnal rhythm of blood pressure. No statistical significant difference was found for night or day BP in diabetic smokers versus non-smokers. The finding of a significantly lower BP in healthy (supine) smokers at night speaks against dysautonomia explaining the lower clinic BP found in epidemiological studies, as recently proposed. Alternatively a rebound effect or the existence of a substance with vasodilating properties in non-diabetic smokers is suggested.(ABSTRACT TRUNCATED AT 250 WORDS)

Diurnal blood pressure variations in normoalbuminuric type 1 diabetic patients

OBJECTIVE

To test the hypothesis that normoalbuminuric type 1 diabetic patients segregate into groups with normal and elevated ambulatory blood pressure. To evaluate diurnal variation of blood pressure assessed by individual or fixed night-time periods.

DESIGN

Cross-sectional study.

SETTING

Tertiary referral centre.

SUBJECTS

Inclusion criteria for type 1 diabetic patients (n = 33): normal urinary albumin excretion (UAE age < 45 < 20 micrograms min-1), diabetes duration < or = 20 years, age 45 years. Healthy controls (n = 33) were matched for sex and age.

MAIN OUTCOME MEASURE

Twenty-four hour, day-time, night-time and night/day ratio of ambulatory blood pressure.

RESULTS

Twenty-four-hour blood pressure in diabetic patients did not differ significantly from a normal distribution. The 24-h systolic blood pressure was higher in diabetic patients than in healthy controls (difference: 6 mmHg, 95% confidence interval (CI) from 1 to 10 mmHg, P < 0.05), while no significant differences were found for diastolic values. The 24-h systolic blood pressure in diabetic patients with UAE above the median value (5.8 micrograms min-1) was higher than for those with lower UAE (difference: 7 mmHg, 95% CI from 0.5 to 13 mmHg, P < 0.05). The night/day ratio of diastolic blood pressure based on individual informations of the night period was (mean +/- SD) 80 +/- 6% in diabetic patients and 78 +/- 8% in controls (difference: 2%, 95% CI from -1 to 5%, not significant [NS]). This ratio increase significantly (P < 0.00001) to 90 +/- 5% in diabetes and to 84 +/- 7% in controls if a fixed night period from 22.30 hours to 06.30 hours was assumed.

CONCLUSIONS

It was not possible to identify a well-separated group of normoalbuminuric type 1 diabetic patients with elevated ambulatory blood pressure. Values of UAE above the median in diabetic patients are associated with higher ambulatory blood pressure. Assessment of the night/day variation from fixed time-points should be abandoned because this leads to a serious underestimation of the nocturnal reduction in blood pressure.

Monitoring diabetic nephropathy: glomerular filtration rate and abnormal albuminuria in diabetic renal disease--reproducibility, progression, and efficacy of antihypertensive intervention

The principal end point in the evaluation of treatment in incipient and overt diabetic nephropathy is rate of decline in glomerular filtration rate (GFR). Therefore, information on reproducibility of GFR measurements is essential in the planning and evaluation of clinical trials. We studied reproducibility of GFR measurements in insulin-dependent and non-insulin-dependent diabetes mellitus patients using, respectively, a constant-infusion technique with urine collection and labeled iothalamate as a tracer marker and a single-shot procedure using Cr-EDTA, measuring the GFR from the decline in plasma level after bolus injection. The coefficient of variance in the insulin-dependent patients was from 7.5% to 8.8% with repeated measurements. In longitudinal studies with several measurements the mean coefficient of variances varied between 7.4% and 3.4%. In the non-insulin-dependent patients the coefficient of variances between two tests were 7.0% and 5.3% for normoalbuminuric and microalbuminuric patients, respectively. In cross-sectional studies as well as in longitudinal studies, it has been consistently shown that GFR is well preserved and at a supranormal level in patients with normoalbuminuria and microalbuminuria. A decline in GFR appears to start around the transition from microalbuminuria to overt diabetic renal disease, although more detailed studies are needed to support this finding. With regard to intervention trials, several studies document that microalbuminuria can be reduced by effective antihypertensive treatment, particularly with angiotensin-converting enzyme inhibitors, also in patients with normal or close to normal blood pressure. Preliminary results from long-term studies suggest that reduction in microalbuminuria in these patients is associated with preservation of GFR and, thus, apparently renoprotection. In patients with overt renal disease, it has been consistently shown that antihypertensive treatment reduces albuminuria as well as the rate of decline in GFR. This is also observed with combined treatment regimens, for instance beta blockers or angiotensin-converting enzyme inhibitors combined with diuretics, or the three types of drugs in combination.

Acute renal effects of angiotensin converting enzyme inhibition in microalbuminuric type 1 diabetic patients

The renal effects of intravenous injection of 10 mg enalapril were investigated in 16 normotensive microalbuminuric type 1 (insulin-dependent) diabetic patients. After enalapril the following changes were observed: fractional albumin clearance (theta Alb) decreased from 9.9 (3.0-23.8) to 8.2 (2.0-18.3) x 10(-6) (2 P < 0.01); filtration fraction (FF) decreased from 0.260 (0.225-0.312) to 0.253 (0.190-0.297) (2 P < 0.01); renal plasma flow (RPF) increased from 565 (411-690) to 623 (449-785) (2 P < 0.01); and glomerular filtration rate (GFR) remained stable at 149 (128-181) versus 150 (124-185) ml.min-1 (NS). These values were unchanged after placebo (n = 8), except for RFP which decreased from 606 (401-701) to 559 (381-677) ml.min-1 (2 P < 0.05) and GFR which was reduced from 148 (111-173) to 138 (111-167) (2 P < 0.05). A reduction in mean blood pressure from 94 (87-103) to 89 (79-101) mmHg (2 P < 0.05) was found in the enalapril group and a minor reduction in the placebo group from 97 (83-106) to 96 (81-104) mmHg (2 P < 0.05) was also noted. The relative changes in systolic blood pressure in the enalapril group correlated with changes in theta Alb (Spearman's r = 0.66, 2 P < 0.02) and FF (r = 0.53, 2 P < 0.05). Acute inhibition of angiotensin converting enzyme does not reduce the pathological hyperfiltration in these patients and a reduction in theta Alb and FF can not be dissociated from the reduction in blood pressure.

Determinants of intra-individual variation in kidney function in normoalbuminuric insulin-dependent diabetic patients: importance of atrial natriuretic peptide and glycaemic control

1. In order to investigate the modulation of kidney function in insulin-dependent diabetes mellitus, intraindividual variation in glomerular filtration rate, renal plasma flow, urinary albumin excretion rate and mean arterial blood pressure was assessed in 22 normoalbuminuric patients [age 31 +/- 8 years, duration of diabetes 9 +/- 5 years, mean arterial blood pressure 90 +/- 5 mmHg (means +/- SD), urinary albumin excretion rate 5.4 x/divided by 1.6 micrograms/min]. The variation in these parameters was calculated from the results of two clearance studies (continuous infusion of [125I]-iothalamate and 131I-hippuran as markers for glomerular filtration rate and renal plasma flow, respectively) and was subsequently analysed in relation to individual variation in plasma concentrations of atrial natriuretic peptide, arginine vasopressin, angiotensin II and aldosterone and measures of glycaemic control. 2. Simple correlation analysis showed a significant association between intra-individual variation in glomerular filtration rate and atrial natriuretic peptide (sigma = 0.66, P = 0.003). Besides variation in atrial natriuretic peptide, multiple regression analysis identified variation in glycated haemoglobin (P = 0.026) and arginine vasopressin (P = 0.057) as variables having independent association with variation in glomerular filtration rate [R2 with the three variables included (adjusted for degrees of freedom) = 0.50, analysis of variance: P = 0.002]. 3. With respect to variation in renal plasma flow, differences in fasting blood glucose concentration and mean arterial blood pressure were suggested as determinants (R2 = 0.36, analysis of variance: P = 0.009). 4. Variation in urinary albumin excretion rate (after log transformation) was statistically associated with variation in glycated haemoglobin.(ABSTRACT TRUNCATED AT 250 WORDS)

A randomized comparison of intranasal and injectable octreotide administration in patients with acromegaly

Fifteen acromegalic patients received four single doses of octreotide in random order (500 micrograms, 1000 micrograms, and 2000 micrograms applied intranasally and 100 micrograms given sc). Serum octreotide and GH data were subjected to pharmacokinetic analyses, and local nasal effects were evaluated by acoustic rhinometry. Average areas (+/- SEM) under the serum octreotide curves were: 2000 micrograms: 4597 +/- 536; 1000 micrograms: 1923 +/- 439; 500 micrograms: 957 +/- 168; and 100 micrograms sc: 896 +/- 81 micrograms.L-1.min (n = 13). The calculated relative availability was 27% +/- 0.03; 22% +/- 0.05; 22% +/- 0.03, respectively, for the three nasal doses. The rate of absorption after intranasally administered octreotide was greater than after sc application: t1/2 ka: 7.1 +/- 1.6; 7.9 +/- 1.6; 11.3 +/- 1.9, respectively, vs. 24.1 +/- 2.5 min, whereas the rates of disappearance were similar. GH suppression started immediately after application and reached minimum levels 1-2 h later. The average intervals during which serum GH was below 50% of preadministration values were: 2000 micrograms: 544 +/- 47; 1000 micrograms: 423 +/- 56; 500 micrograms: 289 +/- 52 vs. 351 +/- 34 min after sc injection of 100 micrograms. With 2000 micrograms intranasally all but one of the 15 patients attained constant suppression of serum GH below 5 micrograms/L for 273 to 680 min. Pharmacokinetic analysis demonstrated that 100 micrograms sc and 1000 micrograms intranasally induced the same GH suppressive effect and that 2000 micrograms intranasally approximately doubled the duration of action. Acoustic rhinometry was performed after nasal application of the largest dose of 2000 micrograms and after carrier (n = 9). A highly significant tumescence of the nasal mucosa was maximal after 10 min and gradually receded over the next 2 h. However, this was felt by the patients to be acceptable. The effect was caused by octreotide per se and was probably due to vasodilation.

Ambulatory blood pressure in microalbuminuric type 1 diabetic patients

Twenty-four-hour ambulatory blood pressure (AMBP) was performed in microalbuminuric (micro.) type 1 diabetic patients, with the aim of comparison with a matched group of normoalbuminuric patients (normo.) and healthy controls. Thirty-four patients without antihypertensive medication were investigated in each group. Urinary albumin excretion (UAE) for micro. was (geometric mean, tolerance factor microgram/min) 51.7 x/divided by 1.94, 5.1 x/divided by 1.88 for normo. and 5.2 x/divided by 1.75 for controls. Twenty-four-hour AMBP (mean systolic/diastolic mm Hg +/- SD) was significantly higher in micro. (131 +/- 10/78 +/- 7) than in normo. (122 +/- 8/73 +/- 6; P less than 0.001/P less than 0.01). No 24-hour AMBP difference between normo. and controls (120 +/- 9/71 +/- 7) was found. No difference in the night/day ratio of blood pressure was found between the diabetic groups. Coefficient of variation for day time systolic measurements did not show any intergroup difference. Systolic day time blood pressure for the pooled diabetic group correlated significantly with UAE (r = 0.45, P less than 0.001), whereas no significant correlation with auscultatory systolic values in the clinic was found (r = 0.21; P = 0.09). In conclusion, blood pressure in micro. as compared to normo. is not more labile but is elevated day and night without significant alteration of the diurnal rhythm. AMBP reflects the association between UAE and blood pressure more precisely than clinical measurements and may be preferable for identifying candidates for antihypertensive treatment.

Effects of ACE inhibition supplementary to beta blockers and diuretics in early diabetic nephropathy

Angiotensin converting enzyme (ACE) inhibition has shown promising results in diabetic nephropathy, but long-term results on survival are not available. In a cohort of patients receiving antihypertensive treatment predominantly consisting of beta blockers in combination with diuretics, support for an improved survival has been presented. Addition of ACE inhibition to such a combination treatment may be favorable both due to the suggested renoprotective effects of ACE inhibitors and because diuretics activate the renin-angiotensin system. In 10 insulin-dependent diabetic patients with early diabetic nephropathy [urinary albumin excretion rate (UAE) less than 100o micrograms/min], who were receiving continuous therapy with metoprolol and bendroflumethiazide, a double-blind crossover study with four months addition of ramipril 5 mg (Ramace) and placebo was conducted. UAE (radioimmunoassay) and fractional albumin excretion were significantly reduced after the four months of ramipril administration [UAE: 114.1 x/divided by 1.3 (geometric mean x/divided by confidence factor] versus 174.6 x/divided by 1.2 micrograms/min, 2P less than 0.005). Renal plasma flow (clearance of 131I-hippuran) tended to increase [497 +/- 25 (mean +/- SE) vs. 464 +/- 28 ml/min/1.73 m2, 2P = 0.08], while GFR (125I-iothalamate) stayed unchanged (121 +/- 8 vs. 120 +/- 9 ml/min/1.73 m2). Mean arterial pressure during clearance studies fell moderately (95 +/- 3 vs. 101 +/- 1 mm Hg, 2P less than 0.05) and renal resistance was decreased (2P less than 0.03). ACE activity was suppressed in all patients. Twenty-four-hour ambulatory blood pressure measurements were not significantly different after the two periods (daytime averages: 91 +/- 2 vs. 93 +/- 2, nighttime 80 +/- 2 vs. 84 +/- 3 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

ACE-inhibition and renoprotection in early diabetic nephropathy. Response to enalapril acutely and in long-term combination with conventional antihypertensive treatment

Early antihypertensive treatment with beta1 blockers and diuretics has proved to delay progression in diabetic nephropathy. Application of angiotensin converting enzyme inhibitors (ACE-I) may also be relevant. To elucidate possible differences in acute renal response to ACE-I and beta-blockers, kidney function was investigated before and after enalaprilat (10 mg) and metoprolol (10 mg) i.v. in 8 microalbuminuric insulin-dependent diabetic patients on no antihypertensive therapy (Study A). Glomerular filtration rate (clearance of 125I-iothalamate) was unchanged with both agents. ACE-I gave rise to efferent renal vasodilation: renal resistance and filtration fraction fell, renal plasma flow (RPF; 131I-hippuran) tended to rise (2p = 0.07) and blood pressure and urinary albumin excretion rate (UAE; radioimmunoassay) were reduced. In contrast, metoprolol caused a decline in RPF, an increase in renal resistance and filtration fraction, and no change in blood pressure or UAE. In 10 diabetic, nephropathic patients undergoing treatment with metoprolol and thiazide (Study B), the acute response to enalaprilat corresponded closely to that observed in Study A, including a decrease in UAE and blood pressure. Over 6 months the addition of enalapril (20 mg/d) to metoprolol and thiazide produced a more pronounced UAE-reduction, although no significant decrease in blood pressure was observed. The present findings support that ACE-I may process specific renoprotective effects. A combination therapy with beta1 blockers, ACE-I, and diuretics is suggested.

Renal factors influencing blood pressure threshold and choice of treatment for hypertension in IDDM

In this article, we analyze the blood pressure (BP) threshold for the start of antihypertensive treatment in insulin-dependent diabetes mellitus (IDDM) patients, with particular emphasis on those with persistent microalbuminuria or proteinuria (incipient and overt nephropathy, respectively). In such individuals, there is a clear increase in the prevalence of hypertension and in actual measured BP values that is not observed in normoalbuminuric patients. In 94 young healthy adults (less than 45 yr of age), average mean +/- SD arterial pressure (MAP; diastolic + 1/3 pulse pressure) was approximately 90.0 +/- 8.1 mmHg, closely corresponding to large population studies. In microalbuminuric IDDM patients, MAP values between approximately 105 and approximately 95 mmHg have been found in different studies, and the level has progressively decreased in various studies between 1984 and 1990 with similar BP-measuring techniques. Somewhat higher values are seen in patients with proteinuria, who are also consistently characterized by reduced glomerular filtration rate (GFR). A clear correlation is found between MAP plotted against the increased rate of microalbuminuria (%/yr) in incipient nephropathy and against fall rate of GFR (ml.min-1.mo-1) in proteinuric patients. In the natural history of renal disease, different cutoff points in MAP for start of progression are observed: greater than 95 mmHg for the start of progression of microalbuminuria and greater than 105 mmHg for the decrease in GFR. During antihypertensive treatment, there is reduction or no progression in microalbuminuria with MAP of approximately 90-95 mmHg and only a limited fall in GFR with MAP of approximately 100 mmHg. However, certain antihypertensive drugs (angiotensin-converting enzyme inhibitors) may have specific renoprotective actions, reducing microalbuminuria at rather low BP levels or even independent of BP reduction. The optimal way of monitoring BP may be by 24-h ambulatory recording.

Ambulatory blood pressure measurement in type 2 diabetic patients: methodological aspects

Ambulatory blood pressure was measured over 24 h on two occasions in 29 Type 2 diabetic patients age 65 (range 52-74) years, and the reproducibility compared with that of ordinary clinic measurements recorded by Hawskley's random zero sphygmomanometer. The variability of the difference between blood pressure measurements on the two occasions was twice as large for clinic measurement as for ambulatory measurement (2p less than 0.01). If applied to clinical trials this would allow a fourfold reduction of patient numbers without losing test power. In the group of patients treated with antihypertensive medication (n = 16) the spontaneous decline in blood pressure after leaving the hospital proved to be most prominent in those patients with the highest clinic blood pressure, a phenomenon with importance for the management of hypertension. The individual difference between clinic measurements and ambulatory day-time measurements from the same day was unpredictable. Ambulatory blood pressure measurement in the outpatient clinic may be a practicable approach for optimizing antihypertensive treatment in Type 2 diabetic patients.

Reduction of glomerular hyperfiltration in normoalbuminuric IDDM patients by 6 mo of aldose reductase inhibition

Hyperglycemia causes enhanced glucose metabolism by the polyol pathway in tissues not requiring insulin for glucose uptake. It has been suggested that the high level of aldose reductase activity may cause functional and structural abnormalities in diabetes and may be involved in the development of late complications. To elucidate the effect of an aldose reductase inhibitor (ponalrestat) on kidney function in uncomplicated insulin-dependent diabetes mellitus (IDDM), 20 normoalbuminuric IDDM patients were randomized to follow either 6 mo of treatment with ponalrestat (n = 11, mean +/- SD age 30 +/- 8 yr, diabetes duration 10 +/- 6 yr) or 6 mo of placebo (age 33 +/- 7 yr, diabetes duration 12 +/- 6 yr). The glomerular filtration rate (clearance of [125I]iothalamate) was significantly reduced from 140 +/- 18 to 129 +/- 10 ml.min-1.1.73 m-2, 2P = 0.02) in the ponalrestat-treated patients, whereas no change was seen after placebo (142 +/- 12 vs. 141 +/- 12 ml.min-1.1.73 m-2). The renal plasma flow (clearance of 131I-labeled hippuran), urinary albumin excretion rate (radioimmunoassay), fractional albumin clearance, and renal vascular resistance were unchanged in both groups. HbA1c showed a modest increase during ponalrestat (7.9 +/- 1.8 vs. 8.7 +/- 1.5%, 2P = 0.01) but was unchanged during placebo. No side effects of ponalrestat were observed. Thus, inhibition of aldose reductase may reduce the characteristic hyperfiltration in uncomplicated IDDM.

Blood pressure by 24 h ambulatory recordings in type 2 (non-insulin dependent) diabetics. Relationship to urinary albumin excretion

The relationship between blood pressure and microalbuminuria, both associated with cardiovascular disease and death, is sparsely studied in Type 2 (non-insulin-dependent) diabetes, and results may be interfered by the phenomenon of "white-coat-hypertension". We therefore investigated blood pressure by 24h ambulatory recordings (oscillometry) and examined whether blood pressure related to the level of urinary albumin excretion rate (UAER) by synchronous 24h collections. Seventeen diabetics (50-75 years of age) with microalbuminuria (15 less than UAER less than 200 micrograms/min) (DM), 15 with normal urinary albumin excretion (DN) and 10 healthy controls (C) participated. All groups were of comparable sex, age degree of obesity and had normal serum creatinine, and the groups of diabetics were of similar known duration, glycemic control and frequency of antihypertensive treatment. Blood pressures measured at the clinic were significantly higher (p less than 0.01) than 24h recordings. An average systolic pressure of 142 +/- 11 mmHg in DN was increased (p less than 0.01) as compared to C: 130 +/- 10 mmHg, but no further increase was seen in DM: 146 +/- 19 mmHg. Diastolic pressures were not different among the groups (C: 77 +/- 8 mmHg, DN: 80 +/- 11 mmHg, DM: 79 +/- 9 mmHg). Average 24h systolic pressure correlated to the UAER r = 0.61, p = 0.009 in DM, whereas not in DN. By the present method we found isolated systolic hypertension in Type 2 diabetes which may express "vascular stiffness". There was, however, no further rise in blood pressure in patients with microalbuminuria, but in these patients albuminuria may be pressure dependent and/or expressive of vascular pathology.

Lipoproteins and diuretics in type II diabetes

This double-blind cross-over study was performed to investigate whether the lipoproteins in plasma were different on furosemide (Lasix Retard) and thiazide (hydrochlorthiazide) treatment in patients suffering from type II diabetes. Twenty-four patients were randomly allocated to either furosemide-hydrochlorthiazide (LR-HCT) or HCT-LR treatment. The treatment period was 12 months: 6 months on each sequence. After inclusion, the patients were seen every second month. Laboratory data were recorded at each visit. The only significant treatment effect was observed for high-density-lipoprotein3 cholesterol concentration (HDL3 cholesterol concentration), which was higher when patients were on furosemide therapy (p less than 0.05). We conclude from the present study that blood-glucose HbA1c, and the concentration of lipoproteins connected to development of atherosclerosis is unaffected whether type II diabetes patients are treated with HCT or furosemide.

Renal and glycemic determinants of glomerular hyperfiltration in normoalbuminuric diabetics

Glomerular hyperfiltration is a characteristic feature of insulin-dependent diabetes. We examined the relative roles of renal size, as well as glycemic parameters (HbA1c, glycosylated albumin, plasma glucose) in addition to growth hormone, somatomedin C, beta-hydroxybutyrate, alanine, and glycerol in determining the glomerular filtration rate (GFR). Sixty-two insulin-dependent patients with normal urinary albumin excretion rates (AER less than 15 micrograms/min), who were less than 50 years of age, were included in the study. Data were subjected to multiple regression analysis with GFR as a dependent variable. Renal volume was the primary statistical determinant of hyperfiltration, but HbA1c also significantly correlated with GFR. No correlation was found with glycosylated albumin or blood glucose, but RPF correlated strongly with GFR, and borderline correlation was found between renal volume and HbA1c. Renal hyperfiltration, defined as a GFR greater than 150 ml/min, was found in approximately 50% of patients with HbA1c values greater than 9.5%. Other studies suggest that such patients have a much higher risk of developing clinically evident diabetic nephropathy over the ensuing years. Renal volume appears to be the major determinant of GFR, but long-term metabolic control, as evidenced by the level of HbA1c, also contributes, partly independent of renal volume. Short-term metabolic control, as evaluated by blood glucose and serum-fructosamine, did not correlate with GFR. We suggest that exact determination of GFR and renal volume should be included in long-term prospective controlled intervention trials in patients with insulin-dependent diabetes mellitus (IDDM).

Lack of effects of angiotensin-converting enzyme (ACE)-inhibitors on glucose metabolism in type 1 diabetes

To evaluate the impact of ACE-inhibitors on insulin-mediated glucose uptake, glucose-induced glucose uptake, and hepatic glucose production, a sequential glucose clamp was performed in eight normotensive Type 1 diabetic patients after 3 weeks of enalapril therapy 20 mg day-1 and during control conditions. The experiments were carried out in random order. Mean arterial blood pressure was significantly reduced during ACE-inhibition (95 +/- 3 (+/- SE) vs 84 +/- 3 mmHg; p less than 0.02), while blood glucose control as assessed by HbA1c was unaltered (7.9 +/- 0.5 vs 7.6 +/- 0.5%). The night prior to the study normoglycaemia was maintained by a Biostator. A two-step hyperinsulinaemic euglycaemic clamp (insulin infusion rate 0.3 and 0.8 mU kg-1 min-1) was followed by a hyperinsulinaemic and hyperglycaemic clamp (insulin infusion rate 0.8 mU kg-1 min-1, plasma glucose 11 mmol l-1). Insulin concentrations were comparable with and without enalapril treatment. During the hyperinsulinaemic clamps isotopically determined glucose disposal was unchanged (low dose 2.5 +/- 0.3, high dose 4.3 +/- 0.7 vs 2.6 +/- 0.3 and 4.3 +/- 0.7 mg kg-1 min-1, enalapril vs control). Glucose-induced glucose disposal (9.2 +/- 1.2 vs 9.1 +/- 1.2 mg kg-1 min-1) was also similar, as were non-protein respiratory exchange ratios (indirect calorimetry). Glucose production was not changed by enalapril. In conclusion, treatment with enalapril has no significant effect on glucose metabolism in Type 1 diabetes.

Reducing protein in the diabetic diet

Long-term protein intake may have pathogenic influence on development of late diabetic complications. A review of the latest results in insulin-dependent diabetic patients shows that short-term lowering of protein intake reduces the characteristic early glomerular hyperfiltration as well as microalbuminuria and proteinuria in diabetic nephropathy. A sustained beneficial effect on the progression rate of nephropathy may be achieved. Based on this evidence it is advisable to avoid the traditionally high protein intake in diabetes. We suggest a protein-controlled diet--with protein comprising 14 energy %--as a goal in uncomplicated diabetes. In patients with progressive albuminuria or proteinuria prescription of a low-protein diet with 10% protein should be considered as supplementation to antihypertensive treatment. At present we do not find sufficient evidence for suggesting an intake of 10% protein (corresponding approximately to recent recommendations on 0.8 g prot/kg body weight) also in uncomplicated diabetes. Both a 10 and 14% protein diet will differ somewhat from the diet of the background population and the present diet of many diabetic patients. Therefore the introduction of such diets requires a careful individualized diet therapy in which repetitive evaluation and estimation of compliance are performed. A reduction of protein intake to 10 energy % represents a profound diet intervention.

Effects of felodipine on urinary albumin excretion and metabolic control in hypertensive non-insulin-dependent diabetics

The effect of a blood pressure reduction by 10 mg extended release felodipine once daily on urinary albumin excretion (UAE) as well as the possible diabetogenic effect of felodipine was studied. A 2 X 12 week placebo-controlled double-blind crossover study was performed in 12 hypertensive non-insulin-dependent diabetic (NIDDM) patients without nephropathy on concomitant treatment with beta-blocker and/or a diuretic agent. Metabolic control as estimated by fasting plasma glucose, hemoglobin A1c and fasting plasma C-peptide was unaltered after felodipine. Blood pressure was significantly reduced by felodipine: systolic 166 +/- 26 mm Hg (placebo) v 153 +/- 26 mm Hg (felodipine) (P less than .05) and diastolic 95 +/- 7 mm Hg v 90 +/- 8 mm Hg (P less than .05). Heart rate was unchanged. There was no correlation between blood pressure and UAE, but the relative change in UAE expressed as UAE placebo/UAE felodipine was significantly correlated to the fall in systolic blood pressure (r = 0.64, P = .03) and mean blood pressure (r = 0.66, P = .02). Since microalbuminuria predicts proteinuria and reduced survival, early antihypertensive treatment may be beneficial in NIDDM as it is in IDDM. Long-term consequences on kidney function and mortality remains, however, to be elucidated.

Acute effects of a somatostatin analogue on kidney function in type 1 diabetic patients

Suppression of growth hormone by means of somatostatin has been suggested as a possible adjunct therapy in Type 1 diabetes. To assess the acute effect of the somatostatin analogue SMS 201-995 on kidney function in uncomplicated Type 1 diabetes, 13 normoalbuminuric, normotensive diabetic patients were investigated before and during IV infusion of SMS 201-995 (8 micrograms h-1). A control experiment with infusion of carrier only was also performed. The SMS infusion induced a reduction in the glomerular filtration rate (clearance of 125I-iothalamate) and renal plasma flow (131I-hippuran) from 140 +/- 15 (mean +/- SD) and 550 +/- 69 to 131 +/- 14 (2p less than 0.005) and 492 +/- 73 ml min-1 1.73-m-2 (2p less than 0.001), while filtration fraction and total renal resistance rose (both 2p less than 0.001). Urinary albumin excretion rate, blood pressure, and blood glucose concentration were unchanged. Plasma growth hormone and glucagon were significantly suppressed. The reduction in glomerular filtration rate and renal plasma flow correlated with the fall in glucagon concentration (r = 0.57, 2p = 0.04, and r = 0.63, 2p = 0.02). The urinary flow rate was markedly reduced, urine osmolality increased, and fractional excretion of sodium, calcium, and phosphate were reduced. Arginine vasopressin, atrial natriuretic peptide, angiotensin II, and aldosterone were unchanged by the SMS infusion. Thus SMS 201-995 acutely reduces glomerular filtration rate and renal plasma flow in uncomplicated Type 1 diabetes and has an antidiuretic effect. The effects may be related to suppression of glucagon secretion.

Renal effects from limitation of high dietary protein in normoalbuminuric diabetic patients

Glomerular hyperfiltration may be a risk factor for late nephropathy. It has been shown that considerable protein restriction can lower glomerular filtration rate (GFR). To elucidate the effect of moderate protein limitation in type 1 (insulin-dependent) diabetics with normoalbuminuria, eight such patients were selected for the study (age 38 +/- 7 years SD, diabetes duration 21 +/- 9 years). The patients were randomized to follow, alternately, four weeks of their usual protein intake (19% of energy) and four weeks of a limited protein intake (12% of energy). Kidney function was investigated after the two dietary periods. GFR and renal plasma flow (RPF) were measured using a constant infusion technique (125I-iothalamate/131I-hippuran), and urinary albumin excretion (UAE) by radioimmunoassay. It was found that the limited protein diet reduced GFR from 146 +/- 23 to 132 +/- 24 ml/min/1.73 m2 (2P less than 0.005). A tendency towards a fall in RPF was seen (549 +/- 128 vs. 503 +/- 125 ml/min; 2P = 0.06), while total renal resistance rose from 0.17 +/- 0.03 to 0.20 +/- 0.05 mm Hg/ml/min (2P = 0.05). No significant changes in filtration fraction, UAE and blood pressure were seen. HbA1c, fructosamine, insulin dose and body weight were unchanged during the two diets; also serum protein, albumin, phosphate and calcium remained unaltered. Serum urea was significantly reduced on the limited protein intake. Patients were generally pleased with the limited protein diet. Thus, limitation of the often high protein intake in diabetics might be valuable and realistic. The long-term renal protective effect remains to be investigated.

Low-dose dopamine infusion, renal haemodynamics and urinary albumin excretion rate in insulin-dependent diabetics and in normal man

The effect of experimental renal vasodilatation by means of low-dose (2.0 micrograms/kg/min) intravenous dopamine infusion was investigated in 28 insulin-dependent diabetes mellitus (IDDM) patients with normal basal urinary albumin excretion rate (UAE) (less than 15 micrograms/min), 9 IDDM patients with UAE between 15-200 micrograms/min (microalbuminuria), and 7 normal subjects. Glomerular filtration rate (GFR) (thalamate clearance) showed a small increase with dopamine infusion, in the normoalbuminuric IDDM patients from 140 +/- 20 to 146 +/- 20 ml/min (2p less than 0.01), in the microalbuminuric IDDM patients from 146 to 151 ml/min (NS), and in normal subjects from 115 +/- 16 to 122 +/- 15 (2p less than 0.05). A marked increase in renal plasma flow (RPF) (hippuran clearance) was seen in all three groups--533 +/- 82 to 724 +/- 120 ml/min (2p less than 0.01), 574 +/- 69 to 777 +/- 140 ml/min (2p less than 0.01) and 523 +/- 87 to 749 +/- 145 ml/min (2p less than 0.05), respectively. Urinary albumin excretion rate (radioimmunoassay) increased from 5.3 x/divide 1.5 (tolerance factor) to 6.5 x/divide 1.8 micrograms/min (2p less than 0.05) in the normoalbuminuric IDDM patients and from 6.1 x/divide 2.1 to 7.8 x/divide 2.3 micrograms/min (2p less than 0.05) in the normal subjects, while no significant change was seen in the microalbuminuric group of diabetics. Kidney volume (ultrasonic scanning) was significantly enhanced in IDDM patients (294 +/- 73 ml vs. 196 +/- 49 ml). There was no significant correlation between kidney volume and the renal haemodynamic response to dopamine.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemotactic response of neutrophil polymorphonuclear leukocytes in juvenile periodontitis measured by the Leading Front method

Previous studies have implied that chemotaxis defects of neutrophil polymorphonuclear leukocytes (PMNs) can be found in approximately 75% of patients with juvenile periodontitis (JP). In the present study, the Leading Front (LF) method was used to study whether the chemotactic response of PMNs from JP-patients differed from that of adult periodontitis (AP) patients and periodontally healthy control individuals (C). Sixteen JP-patients, 21 AP-patients, and 13 C-individuals were studied. PMNs from each individual, and from a daily reference person were tested against three chemoattractants (N-f-Met-Leu-Phe (FMLP), casein (CA), bacterial chemotactic factor (BCF] and a neutral buffer (Gey's solution (GEY]. Regardless of the test solution a greater difference among individuals could be observed in the JP-group than in the other groups. Apart from this, there were no differences among the groups as regards CA, BCF, and GEY. However, with FMLP, the PMNs of the JP-group had a significantly greater migration distance as compared to the other groups. This finding can probably be ascribed to the fact that the LF method detects other aspects of the PMN response than do the methods used for earlier studies of JP. The finding, in this study, of an enhanced PMN response in JP as regards FMLP may be a reflection of the presence of a non-uniform PMN population whose composition in JP differs from that of the other groups.

Acute and long-term renal effects of angiotensin converting enzyme inhibition in normotensive, normoalbuminuric insulin-dependent diabetic patients

Glomerular filtration rate (GFR) (thalamate clearance), renal plasma flow (RPF) (hippuran clearance), and urinary albumin excretion rate (AER) were measured in 10 normoalbuminuric, normotensive insulin-dependent diabetic patients and 8 normal subjects before and during acute angiotensin converting enzyme (ACE) inhibition by means of enalapril (10 mg IV). The effect of placebo versus enalapril (30 mg day-1) was also studied for 3-month treatment periods in the insulin-dependent diabetic patients. Acute ACE-inhibition caused a decline in filtration fraction (FF) from 0.259 +/- 0.011 (+/- SE) to 0.237 +/- 0.013 (2p less than 0.01) in the diabetic patients, and from 0.210 +/- 0.010 to 0.188 +/- 0.006 (2p less than 0.02) in the normal subjects. Mean arterial blood pressure was lowered from 90 +/- 1 to 84 +/- 2 mmHg (2p less than 0.01) and from 91 +/- 1 to 86 +/- 2 mmHg (2p less than 0.05). No significant change in blood glucose, AER or fractional albumin excretion (theta Alb) was seen in either group. After 3 months of enalapril treatment FF was decreased from 0.253 +/- 0.011 to 0.235 +/- 0.011 (2p less than 0.05), AER from 5.6 x/ divided by 1.7 to 4.3 x/divided by 1.6 micrograms min-1 (2p less than 0.01) and theta Alb from 1.22 +/- 0.22 x 10(-6) to 0.92 +/- 0.12 x 10(-6) (2p less than 0.02). The decline in total renal resistance was not significant (0.175 +/- 0.013 to 0.165 +/- 0.012 mmHg ml-1 min-1) and significant changes in GFR, RPF, mean arterial pressure or HbA1c were not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two methods for measurement of chemotaxis of neutrophil polymorphonuclear leukocytes in vitro

Measurement of chemotaxis of neutrophil polymorphonuclear leukocytes (PMNs) is often performed by micropore-filter methods. However, most of these methods seem to involve considerable inter-individual, intra-individual, and day-to-day variations. The aim of this study was to compare two frequently used micropore-filter methods - the Lower Surface Count (LSC) and the Leading Front (LF) methods - in order to find the more reproducible one. Blood samples from the same individual were drawn on two different days. PMN chemotaxis and random migration was tested by a micropore-filter assay. The chemotaxis chambers were incubated for 60, 90, 120, and 150 minutes, respectively. In all, 144 filters were read by both methods. The LSC method showed large variations both among identically treated filters and among readings from the same filter. These variations were as much as 10 times higher than the variations shown by the LF method. Also, the day-to-day variation was higher with the LSC method than with the LF method. Furthermore, data from the LF method were normally distributed, in contrast to data from the LSC method. Thus, the present study suggests the LF method to be superior to the LSC method in terms of reproducibility.

Lymphocyte and granulocyte function in zinc-treated and zinc-deficient hemodialysis patients

Lymphocyte blast transformation and granulocyte motility were studied in 20 clinically stable hemodialysis patients, 10 of whom were receiving 50 mg of zinc (as zinc acetate) per day and 10 of whom were not. Plasma zinc concentration was significantly higher in zinc-treated than in untreated patients (108 +/- 5 vs. 82 +/- 2 micrograms/dl). Mononuclear cell subpopulation analysis showed equivalent proportions of T lymphocytes and monocytes in both groups, but B lymphocytes were reduced in untreated patients (10 +/- 0.7 vs 14 +/- 0.5%). Lymphocyte blast transformations in response to nonspecific mitogens, soluble antigen and mixed lymphocyte culture were not significantly different in the two groups, nor was lymphocyte zinc concentration. Zinc-treated patients showed significantly greater granulocyte responsiveness to zymosan-activated serum (21 +/- 1 vs. 14 +/- 2 mean), greater chemokinetic activity (50 +/- 4 vs. 27 +/- 3 mean) and higher granulocyte zinc concentration (114 +/- 6 vs. 47 +/- 2 micrograms/10(6) cells) than untreated patients. Granulocyte zinc correlated significantly with plasma zinc (r = 0.81, P less than 0.001) and with granulocyte motility (r = 0.63, P = 0.001). Moderate zinc deficiency in hemodialysis patients does not result in abnormal lymphocyte blast transformation in vitro, but it does result in granulocyte zinc depletion and impaired granulocyte motility.

Salient features of nonsaccharolytic and weakly saccharolytic nonfermentative rods

One hundred and thirty-one strains of nonsaccharolytic and weakly saccharolytic Gram-negative rods recently isolated from clinical specimens were examined with a battery of 74 tests, mostly biochemical. All but five of these strains were thus assigned to established taxa. Alkalinization of amides and organic acids was a particularly useful feature for identifying these bacteria.

Characterization of saccharolytic nonfermentative bacteria associated with man

Features of 378 clinical isolates of saccharolytic, nonfermentative Gram-negative rods and 20 reference strains were examined. All but four of the clinical strains were assigned to recognized taxa, namely Acinetobacter, Chromobacterium, Flavobacterium, Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas maltophilia, Pseudomonas multivorans, Pseudomonas putida, Pseudomonas stutzeri, and Xanthomonas.

Characterization of bacteria by their degradation of amino acids

A procedure for detecting the degradation of amino acids by microorganisms is described, and examples of its use in the characterization of bacteria are presented. The procedure involves inoculating a buffered solution of amino acids with a suspension of bacteria, incubating, chromatographing a sample of the suspension, and detecting degradation in terms of absence of ninhydrin-positive spots.