Association between early cumulative fluid balance and successful liberation from invasive ventilation in COVID-19 ARDS patients — insights from the PRoVENT-COVID study: a national, multicenter, observational cohort analysis

Background

Increasing evidence indicates the potential benefits of restricted fluid management in critically ill patients. Evidence lacks on the optimal fluid management strategy for invasively ventilated COVID-19 patients. We hypothesized that the cumulative fluid balance would affect the successful liberation of invasive ventilation in COVID-19 patients with acute respiratory distress syndrome (ARDS).

Methods

We analyzed data from the multicenter observational ‘PRactice of VENTilation in COVID-19 patients’ study. Patients with confirmed COVID-19 and ARDS who required invasive ventilation during the first 3 months of the international outbreak (March 1, 2020, to June 2020) across 22 hospitals in the Netherlands were included. The primary outcome was successful liberation of invasive ventilation, modeled as a function of day 3 cumulative fluid balance using Cox proportional hazards models, using the crude and the adjusted association. Sensitivity analyses without missing data and modeling ARDS severity were performed.

Results

Among 650 patients, three groups were identified. Patients in the higher, intermediate, and lower groups had a median cumulative fluid balance of 1.98 L (1.27–7.72 L), 0.78 L (0.26–1.27 L), and − 0.35 L (− 6.52–0.26 L), respectively. Higher day 3 cumulative fluid balance was significantly associated with a lower probability of successful ventilation liberation (adjusted hazard ratio 0.86, 95% CI 0.77–0.95, P = 0.0047). Sensitivity analyses showed similar results.

Conclusions

In a cohort of invasively ventilated patients with COVID-19 and ARDS, a higher cumulative fluid balance was associated with a longer ventilation duration, indicating that restricted fluid management in these patients may be beneficial.

Trial registration Clinicaltrials.gov (NCT04346342); Date of registration: April 15, 2020.

Graphical abstract

[Resuscitation among patients with out-of-hospital cardiac arrest; intra-arrest transport, or not?]

A prospective cohort study recently published in JAMA looked at the difference in survival to hospital discharge between intra-arrest transport vs continued on-scene resuscitation among patients with out-of-hospital cardiac arrest (OHCA). The conclusion of this study is that intra-arrest transport is associated with a lower survival compared to continuous on-site treatment. Research by the Amsterdam Resuscitation Study (ARREST) shows that in OHCA patients who are transported intra-arrest, survival decreases significantly if the time on-scene increases. Patients who are transported within 20 minutes have the highest chance of survival. This suggests that the decision for transport should be made early in the resuscitation process. National and regional circumstances (availability of a mobile medical team, distance to hospital etc.), and pre-hospital resuscitation treatments may make that different scenarios can be considered. In some scenarios extracorporeal cardiopulmonary resuscitation (eCPR) can be brought to the patient; in other scenarios the patient can be transported to the eCPR.

Immediate impact of COVID-19 on transplant activity in the Netherlands

The rapid emergence of the COVID-19 pandemic is unprecedented and poses an unparalleled obstacle in the sixty-five year history of organ transplantation. Worldwide, the delivery of transplant care is severely challenged by matters concerning - but not limited to - organ procurement, risk of SARS-CoV-2 transmission, screening strategies of donors and recipients, decisions to postpone or proceed with transplantation, the attributable risk of immunosuppression for COVID-19 and entrenched health care resources and capacity. The transplant community is faced with choosing a lesser of two evils: initiating immunosuppression and potentially accepting detrimental outcome when transplant recipients develop COVID-19 versus postponing transplantation and accepting associated waitlist mortality. Notably, prioritization of health care services for COVID-19 care raises concerns about allocation of resources to deliver care for transplant patients who might otherwise have excellent 1-year and 10-year survival rates. Children and young adults with end-stage organ disease in particular seem more disadvantaged by withholding transplantation because of capacity issues than from medical consequences of SARS-CoV-2. This report details the nationwide response of the Dutch transplant community to these issues and the immediate consequences for transplant activity. Worrisome, there was a significant decrease in organ donation numbers affecting all organ transplant services. In addition, there was a detrimental effect on transplantation numbers in children with end-organ failure. Ongoing efforts focus on mitigation of not only primary but also secondary harm of the pandemic and to find right definitions and momentum to restore the transplant programs.

Ventilator setting in ICUs: comparing a Dutch with a European cohort

BACKGROUND

From data collected during the third International Study on Mechanical Ventilation (ISMV), we compared data from a Dutch cohort with a European cohort. We hypothesised that tidal volumes were smaller and applied positive end-expiratory pressure (PEEP) was higher in the Netherlands, compared with the European cohort. We also compared use of non-invasive ventilation (NIV) and outcomes in both cohorts.

METHODS

A post-hoc analysis of a prospective observational study of patients receiving mechanical ventilation.

RESULTS

Tidal volumes were smaller (7.6 vs. 8.1 ml÷kg predicted bodyweight) in the Dutch cohort and applied PEEP was higher (8 vs. 6 cm H2O). Fewer patients admitted in the Netherlands received NIV as first mode of mechanical ventilation (7.1 vs. 16.7%). Fewer patients in the Dutch cohort developed an ICU-acquired pneumonia (4.5 vs. 12.3%, p < 0.01) and sepsis (5.7 vs. 10.9%, p = 0.03), but more patients were diagnosed as having delirium (15.8 vs. 4.6%, p < 0.01). ICU and in-hospital mortality rates were 19% and 25%, respectively, in Dutch ICUs vs. 26% and 33% in Europe (p = 0.06 and 0.03).

CONCLUSION

Tidal volumes were smaller and applied PEEP was higher in the Dutch cohort compared with international data, but both Dutch and international patients received larger tidal volumes than recommended for prevention or treatment of acute respiratory distress syndrome. NIV as first mode of mechanical ventilation is less commonly used in the Netherlands. The incidence of ICU-acquired pneumonia is lower and of delirium higher in the Netherlands compared with international data.

Transient versus persistent acute kidney injury and the diagnostic performance of fractional excretion of urea in critically ill patients

AIMS

To evaluate the performance of fractional excretion of urea (FeU) for differentiating transient (T) from persistent (P) acute kidney injury (AKI) and to assess performance of FeU in predicting AKI in patients admitted to the ICU.

METHODS

We performed secondary analysis of a multicenter prospective observational cohort study on the predictive performance of biological markers for AKI in critically ill patients. AKI was diagnosed according to RIFLE staging.

RESULTS

Of 150 patients, 51 and 41 patients were classified as having T-AKI and P-AKI, respectively. The diagnostic performance for FeU to discriminate T-AKI from P-AKI on the day of AKI was poor (AUC-ROC = 0.61; 95% CI: 0.49-0.73). The diagnostic performance of FeU to predict AKI 1 and 2 days prior to AKI was poor as well (AUC-ROC = 0.61; 95% CI: 0.47-0.74, and 0.58; 95% CI: 0.43-0.73, respectively).

CONCLUSIONS

FeU does not seem to be helpful in differentiating T- from P-AKI in critically ill patients and it is a poor predictor of AKI.

Association between angiographic culprit lesion and out-of-hospital cardiac arrest in ST-elevation myocardial infarction patients

BACKGROUND

Factors related to the occurrence of out-of-hospital cardiac arrest (OHCA) in ST-elevation myocardial infarction (STEMI) are still poorly understood. The current study sought to compare STEMI patients presenting with and without OHCA to identify angiographic factors related to OHCA.

METHODS

This multicenter registry consisted of consecutive STEMI patients, including OHCA patients with return-of-spontaneous circulation. Patients were treated with primary percutaneous coronary intervention (PCI) and therapeutic hypothermia when indicated. Outcome consisted of in-hospital neurological recovery, scored using the Cerebral Performance Categories (CPC) scale, and 1-year survival. Logistic regression was used to identify factors associated with OHCA and survival was displayed with Kaplan-Meier curves and compared using log rank tests.

RESULTS

In total, 224 patients presented with OHCA and 3259 without OHCA. Average age was 63.3 years and 75% of patients were male. OHCA occurred prior to ambulance arrival in 68% of patients and 48% required intubation. Culprit lesion was associated with OHCA: risk was highest for proximal left coronary lesions and lowest for right coronary lesions. Also, culprit lesion determined the risk of cardiogenic shock and sub-optimal reperfusion after PCI, which were strongly related to survival after OHCA. Neurological recovery was acceptable (CPC≤2) in 77.1% of OHCA patients and did not differ between culprit lesions.

CONCLUSIONS

In the present STEMI population, coronary culprit lesion was associated with the occurrence of OHCA. Moreover, culprit lesion influenced the risk of cardiogenic shock and success of reperfusion, both of which were related to prognosis of OHCA patients.

Approach to hypophosphataemia in intensive care units - a nationwide survey

BACKGROUND

Evidence-based guidelines for monitoring of serum phosphate levels and for the treatment of hypophosphataemia in critically ill patients are lacking. The aim of this survey was to evaluate current practice with respect to diagnosis and treatment of hypophosphataemia in critically ill patients among intensive care unit (ICU) physicians in the Netherlands.

METHODS

A survey was conducted among all hospitals with an ICU in the Netherlands. Paediatric ICUs were excluded from participation. A questionnaire was sent, with questions on practice regarding serum phosphate monitoring and treatment of hypophosphataemia. Respondents returned the questionnaire either by mail or through a web-based survey.

RESULTS

A response was received from 67÷89 ICUs (75%). Respondents mentioned renal replacement therapy, sepsis and malnutrition, as well as surgery involving cardiopulmonary bypass as the most important causes of hypophosphataemia in intensive care unit patients. Of all respondents, 46% reported to measure serum phosphate levels on a daily basis, whereas in 12% serum phosphate levels were measured only on clinical indication. Less than half of the respondents had some sort of guideline for correction of hypophosphataemia. In a vast majority (79%), correction of hypophosphataemia was reported to start with serum phosphate levels.

Inflation and deflation timing of the AutoCAT 2 WAVE intra-aortic balloon pump using the autoPilot mode in a clinical setting

The primary goal of this observational clinical study was to register the occurrence of incorrect inflation and deflation timing of an intra-aortic balloon pump in autoPilot mode. The secondary goal was to identify possible causes of incorrect timing. During IABP assistance of 60 patients, every four hours a strip was printed with the IABP frequency set to 1:2. Strips were examined for timing discrepancies beyond 40 ms from the dicrotic notch (inflation) and the end of the diastolic phase (deflation). In this way, 320 printed strips were examined. A total of 52 strips (16%) showed incorrect timing. On 24 of these strips, the incorrect timing was called incidental, as it showed on only one or a few beats. The other 28 cases of erroneous timing were called consistent, as more than 50% of the beats on the strip showed incorrect timing. We observed arrhythmia in 69% of all cases of incorrect timing. When timing was correct, arrhythmia was found on 13 (5%) of 268 strips. A poor quality electrocardiograph (ECG) signal showed on 37% of all strips with incorrect timing and 11% of all strips with proper timing. We conclude that inflation and deflation timing of the IABP is not always correct when using the autoPilot mode. The quality of the ECG input signal and the occurrence of arrhythmia appear to be related to erroneous timing. Switching from autoPilot mode to operator mode may not always prevent incorrect timing.

Development and validation of PRE-DELIRIC (PREdiction of DELIRium in ICu patients) delirium prediction model for intensive care patients: observational multicentre study

OBJECTIVES

To develop and validate a delirium prediction model for adult intensive care patients and determine its additional value compared with prediction by caregivers.

DESIGN

Observational multicentre study.

SETTING

Five intensive care units in the Netherlands (two university hospitals and three university affiliated teaching hospitals).

PARTICIPANTS

3056 intensive care patients aged 18 years or over.

MAIN OUTCOME MEASURE

Development of delirium (defined as at least one positive delirium screening) during patients' stay in intensive care.

RESULTS

The model was developed using 1613 consecutive intensive care patients in one hospital and temporally validated using 549 patients from the same hospital. For external validation, data were collected from 894 patients in four other hospitals. The prediction (PRE-DELIRIC) model contains 10 risk factors-age, APACHE-II score, admission group, coma, infection, metabolic acidosis, use of sedatives and morphine, urea concentration, and urgent admission. The model had an area under the receiver operating characteristics curve of 0.87 (95% confidence interval 0.85 to 0.89) and 0.86 after bootstrapping. Temporal validation and external validation resulted in areas under the curve of 0.89 (0.86 to 0.92) and 0.84 (0.82 to 0.87). The pooled area under the receiver operating characteristics curve (n=3056) was 0.85 (0.84 to 0.87). The area under the curve for nurses' and physicians' predictions (n=124) was significantly lower at 0.59 (0.49 to 0.70) for both.

CONCLUSION

The PRE-DELIRIC model for intensive care patients consists of 10 risk factors that are readily available within 24 hours after intensive care admission and has a high predictive value. Clinical prediction by nurses and physicians performed significantly worse. The model allows for early prediction of delirium and initiation of preventive measures. Trial registration Clinical trials NCT00604773 (development study) and NCT00961389 (validation study).

[Dissection of the carotid artery following blunt trauma: still a pitfall]

Two young patients, an 18-year-old woman and a 25-year-old man, were admitted to hospital after accidents with a car. They developed very severe complications as a consequence of blunt carotid artery dissection. This diagnosis was delayed in both patients until serious cerebral ischaemia had occurred. Despite current awareness of carotid dissection as a possible result of blunt trauma, this injury is often overlooked. Early diagnosis by means of Doppler ultrasonography and CT-angiography is important in adequate management of this injury and may reduce morbidity and mortality. The treatment of carotid dissection consists of antithrombotic, endovascular or surgical therapy and needs to be individualized.

[Subarachnoid haemorrhage presenting clinically as circulatory arrest in acute myocardial infarction]

A 59-year-old woman and a 41-year-old man were both brought to the Cardiac Emergency Clinic with circulatory arrest on the basis ofpulseless electrical activity. The first patient had had no prodromal symptoms and the second patient had visited his general practitioner 2 weeks earlier because of pain in the head and neck. In both patients, electrocardiography and echocardiography suggested acute myocardial infarction. However, both patients proved to be suffering from a subarachnoid haemorrhage (SAH) and both died. One-third ofthe patients with SAH are comatose at presentation. Cardiac manifestations such as ECG-abnormalities, cardiac arrhythmias, cardiopulmonary arrest, elevated troponin values, and signs of left ventricular dysfunction are common. These findings can be misleading and may have catastrophic consequences if anticoagulant therapy is initiated because of a presumed myocardial infarction. Low-threshold CT-scanning of the brain is therefore advised for patients who remain comatose after resuscitation for cardiac arrest in the presence of an atypical anamnesis.

Filter Run Time in CVVH: Pre- versus Post-Dilution and Nadroparin versus Regional Heparin-Protamine Anticoagulation

BACKGROUND/AIMS

To study the effect of different modes of continuous veno-venous haemofiltration (CVVH) on filter run time (FRT).

METHODS

We studied, in two consecutive prospective, randomised and crossover studies, 16 and 15 patients with acute renal failure during critical illness. Study A compared pre- versus post-dilution, and study B compared regional anticoagulation with heparin (pre-filter) and protamine (post-filter) (HP) versus nadroparin (NP) pre-filter. All CVVH sessions were standardised. Analyses were by Wilcoxon rank sum tests.

RESULTS

Study A: During pre-dilution the median FRT was 45.7 vs. 16.1 h in post-dilution CVVH (p = 0.005). The median creatinine clearance during pre-dilution was 33 vs. 45 ml/min in post-dilution (p = 0.001). Study B: During NP, median FRT was 39.5 vs. 12.3 h during HP CVVH (p = 0.045).

CONCLUSIONS

Pre-dilution CVVH results in the greatest FRT but a lower plasma creatinine clearance compared to post-dilution. Regional anticoagulation with heparin-protamine resulted in a significantly shorter FRT compared to systemic NP anticoagulation.

A before-after Study of Multi-resistance and Cost of Selective Decontamination of the Digestive Tract

BACKGROUND

We compared standard antibiotic use with an antibiotic policy based on selective decontamination of the digestive tract (SDD) for cost and microbiology.

PATIENTS AND METHODS

A 2-year before-after observational study was performed in an 11-bed, mixed medical and surgical intensive care unit (ICU). We included all consecutive patients admitted to the ICU 1 year before and 1 year after institution of SDD (patients admitted within the 2-month SDD run-in period were excluded from analysis). In the year before SDD, 513 patients were treated in the ICU (mean APACHE II 19.5), compared to 529 in the year with SDD (mean APACHE II 19.4).

RESULTS

The duration of mechanical ventilation was shorter in the SDD-treated patients (median 3, interquartile range [IQR] 2-7 days vs median 4 days, IQR 2-10, p = 0.03). The total of ICU variable costs, microbiological costs and antibiotic costs were equal in both episodes: euro 1,171 versus euro 1,168 per patient). Aerobic gram-negative bacilli (AGNB) and multiresistant AGNB were found less frequently in SDD-treated patients, RR 0.37 (95% CI 0.33-0.42) and RR 0.28 (95% CI 0.19-0.42). Multi-resistant AGNB in tracheal secretions and urine more than 72 hours after admission were completely absent in SDD-treated patients.

CONCLUSION

The overall cost per patient treated during an antibiotic policy including SDD was equal to a policy supporting standard antibiotic care. In addition, duration of ventilation decreased and a trend was shown towards a decreased Length of ICU and hospital stay. Less frequently, cultures from organ sites containing AGNB were found during SDD and the number of multi-resistant strains was significantly reduced at organ sites, in particular trachea and urine. Fewer patients were colonized with multi-resistant AGNB but these numbers did not reach statistical significance.

The woman who could not hold up her head

Low serum potassium concentration is a frequently encountered abnormality, seldom accompanied by life-threatening symptoms. We present a 55-year-old women with a severe, symptomatic hypokalaemia. The pathogenesis and clinical manifestations are discussed.

L-glutamate, L-arginine and L-citrulline levels in cerebrospinal fluid of Parkinson's disease, multiple system atrophy, and Alzheimer's disease patients

Alterations in neuronal nitric oxide (NO) production may play a role in the pathophysiology of Parkinson's disease (PD) Alzheimer's disease (AD), and multiple system atrophy (MSA). The biosynthesis of NO is dependent on the availability of L-arginine, the substrate for NO-synthase (NOS), and on L-glutamate, which stimulates NO synthesis via the NMDA receptor. In this process L-citrulline is formed. We measured the levels of these amino acids in cerebrospinal fluid (CSF) of 108 PD patients, 12 AD patients, 15 MSA patients and 21 healthy subjects. A slight but statistically significant elevation of CSF L-citrulline was found in MSA patients, while CSF L-glutamate was found to be significantly decreased in AD patients. We found no significant changes in L-arginine levels. Although the relation between the CSF levels of these amino acids and neuronal NO production is still unclear, our findings suggest that AD is associated with a decrease in NO synthesis.

Normal cerebrospinal fluid glutathione concentrations in Parkinson's disease, Alzheimer's disease and multiple system atrophy

We measured total glutathione concentrations in the cerebrospinal fluid (CSF) of non-demented Parkinson's disease patients (PD; n=71), demented PD patients (PDD; n=13), multiple system atrophy patients (MSA; n=10), Alzheimer's disease patients (AD; n=17) and age-matched controls (n=21). No statistically significant differences in the mean total CSF glutathione concentrations were found between groups and dopaminomimetic treatment was not found to have any effect on total CSF glutathione levels. Our main conclusion is that total glutathione is not useful as a CSF marker for assumed oxidative stress in patients with PD, MSA or AD.

Dopamine agonists in Parkinson's disease

The main pathologic hallmark of Parkinson's disease is a degeneration of the dopaminergic cells in the substantia nigra, pars compacta and--to a lesser extent--in the ventral tegmental area. Striatal dopamine concentrations are significantly reduced before clinical symptoms become apparent. Recent neuroanatomic and function studies have revealed that the nigrostriatal dopaminergic projection is only one of the neuronal elements integrated into extensive basal ganglia-thalamocortical circuits that are intimately involved in the regulation of motor activity. The possibilities for therapeutic intervention at the level of the different dopamine receptor subtypes and their effect on the regulation of motor behavior will be briefly reviewed. Dopamine precursors are considered to provide the best symptomatic treatment, whereas dopamine agonists, although less effective, might be important in slowing the progression of the disease. Our results with pergolide as monotherapy and in combination therapy in patients with Parkinson's disease also are discussed.

Concentrations of amyloid beta protein in cerebrospinal fluid of patients with Alzheimer's disease

Deposition of fibrillar amyloid beta protein (A beta) is increased in brains of patients with Alzheimer's disease. Concentrations of A beta were measured in cerebrospinal fluid with an enzyme-linked immunosorbent assay in 10 neurological patients free from neurodegenerative disease, 28 patients with Parkinson's disease, and 18 patients with probable Alzheimer's disease. Levels of A beta in cerebrospinal fluid were not significantly different among these groups. This observation suggests that concentrations of soluble A beta in cerebrospinal fluid as measured in this study do not reflect the amount of fibrillar, aggregated A beta in the brain of patients with Alzheimer's disease.

Phenytoin parahydroxylation is not impaired in patients with young-onset Parkinson's disease

Impaired hepatic detoxification capacity by cytochrome P450 subsystems has been implicated in the pathogenesis of Parkinson's disease. We have demonstrated that hepatic parahydroxylation of phenytoin (PHT) is impaired in patients with late-onset Parkinson's disease. In the present study, we have investigated the hypothesis that PHT parahydroxylation is even more impaired in patients with young-onset Parkinson's disease (age at onset before 40 years). We determined PHT parahydroxylation capacity in 21 patients with young-onset Parkinson's disease and 15 healthy age-matched controls. PHT parahydroxylation capacity was assessed by measuring the ratio of PHT to its major metabolite p-hydroxyphenyl-phenylhydantoin in serum 6 h after an oral test dose of 300 mg PHT. PHT parahydroxylation did not differ significantly between patients and controls. These results argue against the hypothesis that impaired activity of the cytochrome P450 isoenzyme responsible for PHT parahydroxylation is involved in the etiology of Parkinson's disease.

Cerebrospinal fluid ferritin levels of patients with Parkinson's disease, Alzheimer's disease, and multiple system atrophy

Iron is believed to play a role in the pathogenesis of both Parkinson's disease (PD) and Alzheimer's disease (AD). We measured ferritin, which is considered to be the iron storage protein, in CSF of patients with PD, AD, and multiple system atrophy (MSA) as well as control subjects. We found a significant increase in CSF ferritin in AD compared with both PD and age-matched controls. No significant differences were found between PD patients with dementia (PDD) and non-demented PD patients. For non-demented PD patients a positive correlation between CSF ferritin and age was found. Our results may indicate that iron has a role in the pathophysiology of AD.

Decreased cerebrospinal fluid nitrate levels in Parkinson's disease, Alzheimer's disease and multiple system atrophy patients

Nitric oxide (NO) is a recently discovered endogenous mediator of vasodilatation, neurotransmission, and macrophage cytotoxicity. NO is thought to have a function in memory and in long-term potentiation. At high concentrations NO is neurotoxic and may play a role in neurodegeneration. NO is formed from L-arginine by the enzyme NO synthase (NOS), for which tetrahydrobiopterin (BH4) is a necessary co-factor. Alzheimer's disease (AD) and, to a lesser degree, Parkinson's disease (PD) are thought to be associated with increased microglial activity, suggesting that NO production may be increased. Alternatively, in circumstances of reduced levels of intracellular L-arginine or BH4, NO production is diminished and neurotoxic oxygen radicals may be produced. Since BH4 is decreased in AD and PD brains, these diseases may be associated with decreased NO production. We investigated these two alternatives by measuring the NO degradation products nitrite and nitrate in cerebrospinal fluid (CSF) of PD (n = 103), AD (n = 13), and multiple system atrophy (MSA; n = 14) patients and controls (n = 20). We found for all patient groups, compared with controls, significantly decreased levels of nitrate, but not nitrite. This finding seems to indicate a decreased NO production of the central nervous system (CNS) in these neurodegenerative disorders.

Re-evaluation of cerebrospinal fluid angiotensin-converting enzyme activity in patients with 'probable' Alzheimer's disease

Angiotensin-converting enzyme activity was measured in lumbar cerebrospinal fluid from patients with 'probable' Alzheimer's disease (n = 17) and age-matched controls (n = 19), using a spectrofluorimetric method. In contrast to a previous finding, no statistically significant difference in the mean (specific) angiotensin-converting enzyme activity was found between the two groups. No correlation existed between (specific) enzyme activity and severity of dementia in the Alzheimer's disease patients. We conclude that angiotensin-converting enzyme in cerebrospinal fluid does not appear to be useful as a potential antemortem marker for Alzheimer's disease.

Whole blood monoamine oxidase activity in Parkinson's disease and multiple system atrophy patients

Monoamine oxidase type B (MAO-B), which catalyses the breakdown of dopamine (DA) in human brain, is said to be involved in the pathophysiology of Parkinson's disease (PD). Activity of MAO-B in PD has been measured in platelets isolated from blood samples in different studies, with contradictory results, possibly due to the differences in substrate used or to differences in platelet isolation. Therefore we measured MAO activity in whole blood, which is almost identical to MAO-B activity in platelets, in 25 drug-naive PD patients, 25 treated PD patients, 9 multiple system atrophy (MSA) patients and 20 controls, using a spectrofluorimetric method with kynuramin as a substrate. No statistically significant differences between groups were found, nor any correlation with the severity or duration of the disease.

Serum alpha 1-antichymotrypsin is not a useful marker for Alzheimer's disease or dementia in Parkinson's disease

We measured serum alpha 1-antichymotrypsin (ACT) levels in patients with Alzheimer's disease (AD), Parkinson's disease (PD), Multiple System Atrophy (MSA) and age-matched controls to evaluate whether serum ACT levels in AD patients were elevated and whether ACT levels in PD patients with dementia differed from those in PD or AD. None of the patient groups displayed an increase in ACT levels. We conclude that serum ACT is not useful as a marker, nor in AD nor in dementia in PD.

X-linked borderline mental retardation with prominent behavioral disturbance: phenotype, genetic localization, and evidence for disturbed monoamine metabolism

We have identified a large Dutch kindred with a new form of X-linked nondysmorphic mild mental retardation. All affected males in this family show very characteristic abnormal behavior, in particular aggressive and sometimes violent behavior. Other types of impulsive behavior include arson, attempted rape, and exhibitionism. Attempted suicide has been reported in a single case. The locus for this disorder could be assigned to the Xp11-21 interval between DXS7 and DXS77 by linkage analysis using markers spanning the X chromosome. A maximal multipoint lod score of 3.69 was obtained at the monoamine oxidase type A (MAOA) locus in Xp11.23-11.4. Results of 24-h urine analysis in three affected males indicated a marked disturbance of monoamine metabolism. These data are compatible with a primary defect in the structural gene for MAOA and/or monoamine oxidase type B (MAOB). Normal platelet MAOB activity suggests that the unusual behavior pattern in this family may be caused by isolated MAOA deficiency.

Multiple system atrophy and progressive supranuclear palsy. Diminished striatal D2 dopamine receptor activity demonstrated by 123I-IBZM single photon emission computed tomography

OBJECTIVE

To measure D2 dopamine receptors in the striatum in patients with multiple system atrophy and progressive supranuclear palsy by I 3-iodo-6-methoxybenzamide labeled with iodine I 123 (123I-IBZM) single photon emission computed tomography and differentiate them from control subjects.

DESIGN

Survey with the following as retrospective criterion standards: (1) parkinsonism, (2) negative apomorphine test, and (3) no or only slight reaction to dopaminergic medication.

SETTING

Ambulatory or hospitalized care in an academic referral center.

PATIENTS AND CONTROL SUBJECTS

Twenty-one patients with parkinsonism not responding to dopaminergic medication (17 with multiple system atrophy and four with progressive supranuclear palsy) and 21 control subjects without parkinsonism.

INTERVENTION

In vivo imaging by single photon emission computed tomography using the D2 dopamine receptor specific radioligand 123I-IBZM.

MAIN OUTCOME MEASURE

Striatum/occipital cortex ratio of count rate density as semiquantitative measurement for striatal D2 dopamine receptor density.

RESULTS

A highly significant loss of striatal uptake of 123I-IBZM was observed in the patients in comparison to the control subjects with little or no overlap between values.

CONCLUSIONS

The hypothesized loss of D2 receptors in multiple system atrophy has been confirmed. Use of 123I-IBZM single photon emission computed tomography may be a cost-effective alternative to positron emission tomography in the differential diagnosis of parkinsonism and in the selection of patients for dopaminergic therapy.