[Christmas article: Goose breast caused by unusual circumstances].

This case report investigate a 61-year-old healthy man who, during a Christmas goose-shooting, got repeated punches on the right breast region, owing to a defective shotgun stock. The initial suggilations and haematomas disappeared in three weeks, but after three months a tender enlargement of the periareolar area developed. Mammography and sonography showed typical right gynaecomastia. History, andrologial examination and biochemistry disclosed no explanation. It was concluded that a traumatic aetiology of the gynaecomastia was most likely. During the next year, the clinical signs regressed somewhat, but control sonography showed leftovers of ductal tissue, and the bird shooter has become reconciled with his "goose breast".

Determination of hepatic clearance by derivations of the indocyanine green retention test in cirrhosis.

BACKGROUND AND AIM: The study was undertaken in order to compare single injection indocyanine green (ICG)-clearances with the steady-state ICG-clearance (ICGCl ) in patients with cirrhosis in order to assess the most accurate estimate for ICG-clearance and to relate the ICG-clearances to established indicators of liver dysfunction. METHODS: Thirty-eight patients (male 29) with cirrhosis (Child-Turcotte class A 8, class B 21, and class C 9) were studied during a hemodynamic investigation. A single injection of ICG was followed by blood samples for 5, 10, 15, and 20 min. The dose/plasma area clearance (ClA ) and plasma volume · initial slope clearance (ClPV ) were determined and compared with the steady-state infusion/plasma concentration ratio clearance (ICGCl ). RESULTS: The ClA (310; 214; 502 mL/min) and ClPV (294; 164; 481 mL/min) correlated closely with ICGCl (243; 120; 383 mL/min [median; interquartile range], R = 0.95-0.98, P < 0.000), but were significantly higher than ICGCl (P < 0.001). All three clearance measures correlated significantly with biochemical and hemodynamic variables of liver dysfunction (P < 0.05-0.000). All three ICG-clearances showed significantly lower values in patients with ascites compared to those without, and lower ICG-clearance values were present in patients with esophageal varices compared to those without (P < 0.05-0.002). CONCLUSION: Single injection markers (ClA and ClPV ) of the steady-state ICG-clearance as derived from the ICG-retention curve and the plasma volume correlate with ICGCl and established variables of portal hypertension and liver cell bile excretory dysfunction. Therefore, these markers can safely replace the more costly ICGCl .

Cortical Activity During an Attack of Ménière's Disease-A Case Report.

Background: Ménière's disease (MD) is a chronic peripheral vestibular disorder with recurrent episodes of vertigo accompanied by fluctuating hearing loss, tinnitus and aural fullness in the affected ear. There are several unanswered fundamental questions regarding MD, one of these being cortical activity during a MD attack. However, it is not possible to plan an investigation in an episodic disease as MD. Objective: To visualize cortical activity during an attack of MD. Method: 18F-FDG PET scans were used to visualize cortical activity in a 62 years old male suffering from definite MD. Two 18F-FDG PET scans were performed. One to show activity during the attack and one to show normal baseline brain activity 7 days after the attack. Results: A number of low-magnitude fluctuations in the 18F-FDG FDG uptake were found in 18F-FDG PET examination following the MD attack compared to the patient's own baseline 18F-FDG FDG scan. Across both hemispheres no significant changes were seen. However, reduced activity was observed in most of the orbitofrontal, frontal cortices as well as Heschl's gyrus and insula. Conclusion: This is the first neuroimaging showing alteration of brain activity during an attack in a patient with MD. No strong focal alterations was seen. It is noteworthy that the decreased activity observed was in the insula and Heschl's gyrus that seems to be core areas for processing information from the labyrinth. It is also of interest that decreased activity rather than hyperactivity was observed.

Neuro-SPECT: On the development and function of brain emission tomography in the Copenhagen area.

This review describes the development of single-photon emission tomography (SPECT) in the Copenhagen area under the leadership of the internationally renown scientist, Niels A. Lassen, and the history leading up to construction of the tomograph. Measurements of global cerebral blood flow (CBF) in the 1940s and 1950s were performed by Kety & Schmidt and Lassen & Munck. Determination of regional cerebral blood flow (rCBF) by intra-arterial injection of 133 Xe and measurement with a 254-multicrystal scintillation detector and a computer system was a major step forward in the study of physiology and pathophysiology of cortical cerebral blood flow. Tomography with radioisotope ligands, including non-invasive administration, was advanced in different centres during the 1970s. An emission tomograph, the Tomomatic 64, was developed as a result of a multidisciplinary Danish and international collaboration. It was the first emission tomograph to provide dynamic data that could produce cross-sectional rCBF images. The present description of the construction and function of the Tomomatic 64 includes comparison with other contemporary and later brain-dedicated SPECT systems. Basic and clinical application of the Tomomatic 64 in Copenhagen resulted in several hundred important scientific publications and improved diagnostics for patients with a variety of neurological disorders. It is concluded that the development of the Tomomatic 64 was a major step forward in the study and examination of rCBF and brain function related to several brain disorders, in addition to vascular diseases.

PET Visualized Stimulation of the Vestibular Organ in Menière's Disease.

Introduction: The cortical metabolic activity in patients with Menière's disease has not been investigated. The aim of this study was to investigate the 18F-FDG cerebral uptake in Menière's patients compared to healthy controls. Method: Eight patients with right-sided Menière's disease and fourteen healthy controls underwent a video head impulse test (vHIT), test of utricular function with ocular vestibular evoked myogenic potentials (oVEMP) and three 18F-FDG-based PET examinations of the brain. Participants were seated in a self-propelled chair, injected with 18F-FDG and then exposed to 35 min of chair motion stimulation, followed by a PET scan. Two types of natural vestibular stimuli were applied, predominantly toward the right horizontal semicircular canal (angular acceleration) and right utriculus (linear acceleration). For baseline scans, participants were injected with 18F-FDG while seated without movement. Results: Analyses of baseline scans revealed decreased 18F-FDG-uptake in the medial part of Heschl's gyrus in the left hemisphere in patients with Menière's disease compared to healthy controls. During angular vestibular stimulation there was also a significantly decreased 18F-FDG uptake in the intersection between the medial part of Heschl's gyrus and the parietal operculum in the left hemisphere and bilaterally in the posterior part of insula. During linear stimulation, Menière's patients showed decreased 18F-FDG uptake in the medial part of Heschl's gyrus in the right hemisphere and also bilaterally in the posterior insula. In addition, decreased 18F-FDG uptake was seen in the thalamus during vestibular stimulation. Conclusion: Heschl's gyrus, the posterior part of insula, and thalamus have previously been shown to be core areas for processing vestibular inputs. Patients with Menière's disease solely differed from the healthy controls with lower cortical activity in these areas at baseline and during natural vestibular stimulation.

Positron emission tomography visualized stimulation of the vestibular organ is localized in Heschl's gyrus.

The existence of a human primary vestibular cortex is still debated. Current knowledge mainly derives from functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) acquisitions during artificial vestibular stimulation. This may be problematic as artificial vestibular stimulation entails coactivation of other sensory receptors. The use of fMRI is challenging as the strong magnetic field and loud noise during MRI may both stimulate the vestibular organ. This study aimed to characterize the cortical activity during natural stimulation of the human vestibular organ. Two fluorodeoxyglucose (FDG)-PET scans were obtained after natural vestibular stimulation in a self-propelled chair. Two types of stimuli were applied: (a) rotation (horizontal semicircular canal) and (b) linear sideways movement (utriculus). A comparable baseline FDG-PET scan was obtained after sitting motion-less in the chair. In both stimulation paradigms, significantly increased FDG uptake was measured bilaterally in the medial part of Heschl's gyrus, with some overlap into the posterior insula. This is the first neuroimaging study to visualize cortical processing of natural vestibular stimuli. FDG uptake was demonstrated in the medial-most part of Heschl's gyrus, normally associated with the primary auditory cortex. This anatomical localization seems plausible, considering that the labyrinth contains both the vestibular organ and the cochlea.

Suppression head impulse paradigm in healthy adolescents - A novel variant of the head impulse test.

BACKGROUND: Suppression Head Impulse Paradigm (SHIMP), a novel variant of the Head Impulse Test has been introduced. At the same time, the Head Impulse Test was renamed to the Head Impulse Paradigm (HIMP). Contrary to HIMP saccades, SHIMP saccades are a sign of vestibular function. OBJECTIVE: 1) To compare SHIMP and HIMP feasibility, vestibular-ocular reflex (VOR) gain value and the saccadic pattern in healthy adolescents. 2) To compare SHIMP and HIMP feasibility in the hands of an experienced and an inexperienced HIMP examiner. METHOD: A total of 29 adolescents from Skåde Municipal School, Denmark were tested with HIMP and then with SHIMP. RESULTS: Neither covert nor overt saccades were observed in the HIMP, whereas SHIMP saccades were observed in all SHIMP reports. SHIMP gain values were statistically lower than HIMP gain values. A statistically significant difference was observed between the two examiners' right SHIMP gain values, but not for the left SHIMP gain values or the HIMP gain values. CONCLUSIONS: We found that HIMP and SHIMP tests are feasible in healthy adolescents for experienced as well as inexperienced examiners. However, one must be aware of potential pitfalls in the execution and interpretation of both tests. This is a well-known fact for the HIMP test, but additional considerations are needed to obtain reliable results from the SHIMP test.

Histological and Molecular Adipose Tissue Changes Are Related to Metabolic Syndrome Rather Than Lipodystrophy in Human Immunodeficiency Virus-Infected Patients: A Cross-Sectional Study.

Background: In human immunodeficiency virus (HIV)-infected patients on combination antiretroviral therapy (cART), lipodystrophy shares many similarities with metabolic syndrome, but only metabolic syndrome has objective classification criteria. We examined adipose tissue changes related to lipodystrophy and metabolic syndrome to clarify whether it may be acceptable to focus diagnosis on metabolic syndrome rather than lipodystrophy. Methods: This is a cross-sectional study of 60 HIV-infected men on cART and 15 healthy men. We evaluated lipodystrophy (clinical assessment) and metabolic syndrome (JIS-2009). We compared adipocyte size, leukocyte infiltration, and gene expression in abdominal subcutaneous adipose tissue biopsies of patients with and without lipodystrophy and with and without metabolic syndrome. Results: Lipodystrophy was only associated with increased macrophage infiltration (P = .04) and adiponectin messenger ribonucleic acid ([mRNA] P = .008), whereas metabolic syndrome was associated with larger adipocytes (P < .0001), decreased expression of genes related to adipogenesis and adipocyte function (P values between <.0001 and .08), increased leptin mRNA (P = .04), and a trend towards increased expression of inflammatory genes (P values between .08 and .6). Conclusions: Metabolic syndrome rather than lipodystrophy was associated with major unfavorable abdominal subcutaneous adipose tissue changes. In a clinical setting, it may be more relevant to focus on metabolic syndrome diagnosis in HIV-infected patients on cART with regards to adipose tissue dysfunction and risk of cardiometabolic complications.

Effects of transjugular intrahepatic portosystemic shunt (TIPS) on blood volume distribution in patients with cirrhosis.

BACKGROUND: Cirrhosis is accompanied by portal hypertension with splanchnic and systemic arterial vasodilation, and central hypovolaemia. A transjugular intrahepatic portosystemic shunt (TIPS) alleviates portal hypertension, but also causes major haemodynamic changes. AIMS: To investigate effects of TIPS on regional blood volume distribution, and systemic haemodynamics. METHODS: Thirteen cirrhotic patients had their regional blood volume distribution determined with gamma-camera technique before and after TIPS. Additionally, we measured systemic haemodynamics during liver vein and right heart catheterization. Central and arterial blood volume (CBV) and cardiac output (CO) were determined with indicator dilution technique. RESULTS: After TIPS, the thoracic blood volume increased (+10.4% of total blood volume (TBV), p<0.01), whereas the splanchnic blood volume decreased (-11.9% of TBV, p<0.001). CO increased (+22%, p<0.0001), and systemic vascular resistance decreased (-26%, p<0.001), whereas CBV did not change. Finally, right atrial pressure and mean pulmonary artery pressure increased after TIPS (+50%, p<0.005; +40%, p<0.05, respectively). CONCLUSIONS: TIPS restores central hypovolaemia by an increase in thoracic blood volume and alleviates splanchnic vascular congestion. In contrast, CBV seems unaltered. The improvement in central hypovolaemia is therefore based on an increase in thoracic blood volume that includes both the central venous and arterial blood volume. This is supported by an increase in preload, combined with a decrease in afterload.

Gamma-variate plasma clearance versus urinary plasma clearance of 51 Cr-EDTA in patients with cirrhosis with and without fluid retention.

In patients with fluid retention, the plasma clearance of 51 Cr-EDTA (Clexp obtained by multiexponential fit) may overestimate the glomerular filtration rate (GFR). The present study was undertaken to compare a gamma-variate plasma clearance (Clgv) with the urinary plasma clearance of 51 Cr-EDTA (Clu ) in patients with cirrhosis with and without fluid retention. A total of 81 patients with cirrhosis (22 without fluid retention, 59 with ascites) received a quantitative intravenous injection of 51 Cr-EDTA followed by plasma and quantitative urinary samples for 5 h. Clgv was determined from the injected dose relative to the plasma concentration-time area, obtained by a gamma-variate iterative fit. Clexp and Clu were determined by standard technique. In patients without fluid retention, Clgv , Clexp and Clu were closely similar. The difference between Clgv and Clu (Clgv - Clu  = ΔCl) was mean -0·6 ml min-1  1·73 m-2 . In patients with ascites, ΔCl was significantly higher (11·8 ml min-1  1·73 m-2 , P<0·0001), but this value was lower than Clexp - Clu (17·5 mL min-1  1·73 m-2 , P<0·01). ΔCl increased with lower values of GFR (P<0·001). In conclusion, in patients with fluid retention and ascites Clgv and Clexp overestimates GFR substantially, but the overestimation is smaller with Clgv . Although Clu may underestimate GFR slightly, patients with ascites should collect urine quantitatively to obtain a reliable measurement of GFR.

The Use of Computer-Assisted Home Exercises to Preserve Physical Function after a Vestibular Rehabilitation Program: A Randomized Controlled Study.

Objective. The purpose of this study was to evaluate whether elderly patients with vestibular dysfunction are able to preserve physical functional level, reduction in dizziness, and the patient's quality of life when assistive computer technology is used in comparison with printed instructions. Materials and Methods. Single-blind, randomized, controlled follow-up study. Fifty-seven elderly patients with chronic dizziness were randomly assigned to a computer-assisted home exercise program or to home exercises as described in printed instructions and followed for tree month after discharge from an outpatient clinic. Results. Both groups had maintained their high functional levels three months after finishing the outpatient rehabilitation. No statistically significant difference was found in outcome scores between the two groups. In spite of moderate compliance levels, the patients maintained their high functional level indicating that the elderly should not necessarily exercise for the first three months after termination of the training in the outpatient clinic. Conclusion. Elderly vestibular dysfunction patients exercising at home seem to maintain their functional level, level of dizziness, and quality of life three months following discharge from hospital. In this specific setup, no greater effect was found by introducing a computer-assisted training program, when compared to standard home training guided by printed instructions. This trial is registered with NCT01344408.

Red blood cell sodium transport in patients with cirrhosis.

Patients with advanced cirrhosis have abnormal sodium homoeostasis. The study was undertaken to quantify the sodium transport across the plasma membrane of red blood cells (RBC) in patients with cirrhosis. RBC efflux and influx of sodium were studied in vitro with tracer (22) Na(+) according to linear kinetics in 24 patients with cirrhosis and 14 healthy controls. The sodium efflux was modified by ouabain (O), furosemide (F) and a combination of O and F (O + F). RBC sodium was significantly decreased (4·6 versus control 6·3 mmol l(-1) , P<0·001) and directly related to serum sodium (r = 0·57, P<0·05). The RBC fractional sodium efflux was higher in patients with cirrhosis (+46%, P<0·01) compared to controls. Inhibition in both high (145 mmol l(-1) )- and low (120 mmol l(-1) )-sodium buffers showed that the F-insensitive sodium efflux was twice as high in cirrhosis as in controls (P = 0·03-0·007), especially the O-sensitive, F-insensitive efflux was increased (+ 225%, P = 0·01-0·006). Fractional F-sensitive transport was normal in cirrhosis. RBC sodium influx was largely normal in cirrhosis. In conclusion, RBC sodium content is reduced in patients with cirrhosis with a direct relation to serum sodium. Increased RBC sodium efflux is especially related to ouabain-sensitive, furosemide-insensitive transport and thus most likely due to upregulated activity of the sodium-potassium pump. The study gives no evidence to an altered intracellular/extracellular sodium ratio or to a reduced fractional furosemide-sensitive sodium transport in cirrhosis.

Immunosenescence of the CD8(+) T cell compartment is associated with HIV-infection, but only weakly reflects age-related processes of adipose tissue, metabolism, and muscle in antiretroviral therapy-treated HIV-infected patients and controls.

BACKGROUND: Despite effective antiretroviral therapy (ART), HIV-infected patients exhibit systemic inflammation, early onset of age-related diseases, and features of immunosenescence. The role of inflammation in the development of age-related diseases is widely recognized. However, the role of immunosenescence is not well established. Studying immunosenescence in HIV-infection could give insight into its role in ageing processes. In this cross-sectional study, we aimed to investigate whether ART-treated HIV-infected patients exhibit immunosenescence; and whether immunosenescence is associated with age-related processes of inflammation, metabolism, adipose tissue, and muscle. T cell immunosenescence and exhaustion were assessed by flow cytometry analysis of CD8 (+) cells from 43 ART-treated HIV-infected patients (HIV(+)) and ten Controls using markers of differentiation: CD27/CD28; maturation: CD27/CD45RA; senescence: killer cell lectin-like receptor G1 (KLRG1); and exhaustion: programmed death-1 (PD-1). Relationships between CD8 (+) T cell immunosenescence, exhaustion, and age-related processes were assessed using linear regressions. RESULTS: HIV-infection was strongly associated with more highly differentiated and mature CD8 (+) T cell phenotypes. PD-1 and KLRG1 expression did not differ between HIV(+) and Controls, but depended on differentiation and maturation stages of the cells. CD8 (+) T cell maturation was associated with age. KLRG1 expression was associated with age, metabolic syndrome, visceral adipose tissue, and high muscle mass. PD-1 expression was not associated with age-related parameters. CONCLUSIONS: HIV-infection strongly affected CD8 (+) T cell differentiation and maturation, whereas age-related processes were only weakly associated with immune parameters. Our findings suggest that, in contrast to inflammation, immunosenescence appears to be highly dependent on HIV-infection and is only to a small extent associated with age-related parameters in well-treated HIV-infection.

Leptin, IL-6, and suPAR reflect distinct inflammatory changes associated with adiposity, lipodystrophy and low muscle mass in HIV-infected patients and controls.

BACKGROUND: HIV-infected patients could exhibit accelerated ageing, since age-associated complications like sarcopenia; increased inflammation; lipodystrophy with loss of subcutaneous adipose tissue and/or gain of visceral adipose tissue (VAT); and cardiovascular disease occur at an earlier age. Inflammation is involved in age-associated complications. However, it is not understood whether it is the same inflammatory changes that are involved in the various ageing-associated complications. Our objective was to study whether leptin, interleukin 6 (IL-6), and soluble urokinase plasminogen activator receptor (suPAR) were associated distinctively with adiposity, lipodystrophy and sarcopenia, in HIV-infected patients and healthy Controls. RESULTS: Systemic leptin levels were significantly higher in patients with lipodystrophy than without, whereas there was no difference in IL-6 or suPAR levels. Leptin was significantly positively associated with fat mass index (FMI) and abdominal VAT, but not with lean mass index (LMI). IL-6 was significantly associated with both FMI and VAT, and low LMI. High suPAR was associated with low LMI, and weakly with high FMI and VAT. CONCLUSIONS: Leptin reflected adiposity- and lipodystrophy-related inflammation, but not sarcopenia. IL-6 reflected both adiposity-, but also sarcopenia-related inflammation; and suPAR was a marker of sarcopenia-related inflammation. Our results indicate that different inflammatory processes can be active simultaneously contributing to the systemic low grade inflammatory state. Identifying major contributors to circulating leptin, IL-6, and suPAR levels could levels could therefore improve our understanding of which inflammatory processes are involved in the various age-related complications.

Acid-base disturbance in patients with cirrhosis: relation to hemodynamic dysfunction.

PURPOSE: Acid-base disturbances were investigated in patients with cirrhosis in relation to hemodynamic derangement to analyze the hyperventilatory effects and the metabolic compensation. METHODS: A total of 66 patients with cirrhosis and 44 controls were investigated during a hemodynamic study. RESULTS: Hyperventilatory hypocapnia was present in all patients with cirrhosis and progressed from Child class A to C (P<0.01). Arterial pH increased significantly from class A to C (P<0.001) and was correlated inversely to the mean arterial blood pressure (r=-0.30, P<0.02), systemic vascular resistance (r=-0.25, P<0.05), indocyanine green clearance (r=-0.37, P<0.005), and serum sodium (r=-0.38, P<0.002). Metabolic compensation was shown by a reduced standard base excess in all patients (P<0.001). Standard base excess contained elements related to changes in serum albumin, water dilution, and effects of unidentified ions (all P<0.001). A significant hepatic component in the acid-base disturbances could not be identified. CONCLUSION: Hypocapnic alkalosis is related to disease severity and hyperdynamic systemic circulation in patients with cirrhosis. The metabolic compensation includes alterations in serum albumin and water retention that may result in a delicate acid-base balance in these patients.

Total plasma clearance versus urinary plasma clearance of (51)Cr-EDTA in patients with cirrhosis with and without fluid retention.

BACKGROUND AND AIM: In patients with fluid retention, the total plasma clearance of (51)Cr-EDTA (ClP) may overestimate the glomerular filtration rate (GFR). The present study was therefore undertaken in order to compare ClP with the urinary plasma clearance of (51)Cr-EDTA (ClU) in patients with cirrhosis with and without fluid retention. MATERIAL AND METHODS: A total of 136 patients with cirrhosis (24 without fluid retention, 112 with ascites) received a quantitative intravenous injection of (51)Cr-EDTA followed by plasma and quantitative urinary samples for 5 hours. ClP was determined from the injected dose relative to the plasma concentration-time area, extrapolated to infinity. ClU was determined as urinary excretion relative to the plasma concentration-time area up to voiding. RESULTS: In patients without fluid retention, the difference between ClP and ClU (ClP - ClU = ClΔ) was mean 4.5 mL/min/1.73 m(2). In patients with ascites, ClΔ was significantly higher (17.6 mL/min/1.73 m(2), p < 0.0001). ClΔ increased with lower values of GFR (r = - 0.458, p < 0.001). Repeated measurements of ClU in a subgroup of patients with fluid retention (n = 25) gave almost identical values. Different types of corrections of one-pool clearance were almost identical with ClP, except for higher clearance values, which were somewhat underestimated by the former. CONCLUSION: In patients with fluid retention and ascites ClP and corrected one-pool clearance overestimates GFR substantially. Although ClU may underestimate GFR slightly, patients with ascites should collect urine quantitatively in order to obtain a reliable measurement of GFR.

Computer-assisted training as a complement in rehabilitation of patients with chronic vestibular dizziness--a randomized controlled trial.

OBJECTIVE: To compare a computer-assisted home exercise program with conservative home-training following printed instructions in the rehabilitation of elderly patients with vestibular dysfunction. DESIGN: Single-blind, randomized, controlled trial. SETTING: Geriatric department of a university hospital. PARTICIPANTS: Patients with chronic dizziness due to vestibular dysfunction (N=63) were randomly assigned to either rehabilitation in the clinic followed by computer-assisted home exercises (intervention group: n=32) or rehabilitation in the clinic followed by home exercises according to printed instructions (control group: n=31). INTERVENTIONS: Patients in the intervention group received assisted rehabilitation by a computer program. MAIN OUTCOME MEASURES: Measurements at baseline and at 8 and 16 weeks were compared. These included the One Leg Stand Test, Dynamic Gait Index, Chair Stand Test, Motion Sensitivity Test, Short Form-12, Dizziness Handicap Inventory, and visual analog scale. RESULTS: Both groups improved significantly during 16 weeks of rehabilitation. However, neither t tests nor repeated-measures analysis of variance demonstrated any significant differences between the 2 groups. The overall compliance rate to computer program exercises during 16 weeks was 57%. CONCLUSIONS: A computer-assisted program to support the home training of elderly patients with vestibular dysfunction did not improve rehabilitation more than did printed instructions.

The clearance concept with special reference to determination of glomerular filtration rate in patients with fluid retention.

In subjects without fluid retention, the total plasma clearance of a renal filtration indicator (inulin, (99m) Tc-DTPA, (51) Cr-EDTA) is close to the urinary plasma clearance. Conversely, in patients with fluid retention (oedema, pleural effusions, ascites), there is a substantial discrepancy between the total plasma clearance and the urinary plasma clearance. This is owing to delayed indicator distribution to smaller or larger parts of the interstitial space, which in patients with ascites may simulate a peritoneal dialysator. In patients with fluid retention, urinary plasma clearance should be assessed to obtain a correct measurement of the glomerular filtration rate (GFR). In theory, total plasma clearance with late samples (24-h, 48-h) may be applied in patients with fluid retention, but validation hereof has not been performed. Until such studies are completed, it is recommended that patients with fluid retention have their GFR measured by a urinary plasma clearance technique with controlled quantitative urinary sampling within a few hours after indicator injection.

Assessment of in situ adipose tissue inflammation by microdialysis.

BACKGROUND: Inflammation, and specifically adipose tissue (AT) inflammation, is part of the pathophysiology of obesity and HIV-associated lipodystrophy. Local AT protein assessment methods are limited, and AT inflammation studies have therefore primarily examined inflammatory gene expression. We therefore investigated the utility of microdialysis to study in situ AT interstitial inflammatory protein levels. MATERIAL AND METHODS: Abdominal subcutaneous AT microdialysis was performed in six healthy men, six HIV-infected men with lipodystrophy and six without lipodystrophy using the internal references (51) Cr-EDTA and (125) I-human serum albumin. We measured 41 inflammatory proteins in microdialysis samples by Luminex technology, as well as systemic levels in 14 subjects. Furthermore, in vitro studies of the internal reference technique for microdialysis recovery of inflammatory proteins were made. RESULTS: We detected in situ AT interstitial levels of 14 inflammatory proteins by microdialysis, while the 27 other inflammatory proteins assessed were only detected sporadically. Initial levels of IL-6 and IL-8 were undetectable. Insertion trauma affected IL-1α, IL-6, IL-8, monocyte chemotactic factor (MCP)-1, IP-10, G-CSF, growth-related oncogene (GRO), macrophage-derived chemokine (MDC) and macrophage inflammatory protein (MIP)-1ß levels, while fibroblast growth factor (FGF)-2 was not affected. Systemic and AT interstitial levels were poorly correlated. The microdialysis recovery of smaller proteins was higher than for larger, and the internal references improved microdialysis by accounting for variation in perfusion across the membrane. CONCLUSION: Interstitial inflammatory proteins can be sampled in situ using microdialysis. Use of internal references improves the microdialysis technique. However, insertion trauma hampers the use of microdialysis to study AT inflammatory levels, except for FGF-2. Still, microdialysis gives unique insight to in situ AT interstitial concentrations.