Quantitative impact of the first COVID-19 lockdown on nuclear medicine in France: the CORALINE study

PURPOSE

The coronavirus disease 2019 (COVID-19) pandemic reshaped the usual risk: benefit equilibrium that became a trade-off between the infection exposure risk for the patient (and for staff) and the risk associated with delaying or cancelling the nuclear medicine examination. This study aimed at quantifying the impact of the first COVID-19 lockdown in France on nuclear medicine examination volume together with volume of examination cancellation and non-attendance.

METHODS

We retrospectively assessed the volume of planned examinations from 1 month before to 1 month after the first lockdown in French high-volume nuclear medicine departments (NMD) sharing the same information management system including both university hospitals, UH (n = 7), and cancer centres, CC (n = 2).

RESULTS

The study enrolled 31,628 consecutive patients referred for a nuclear medicine examination performed or not (NMEP or NMEnP). The total volume of NMEP significantly dropped by 43.4% between the 4 weeks before and after the starting of the lockdown. The comparison of the percentage of NMEP and NMEnP between UH and CC is significantly different (p < 0.001). The percentage of NMEP during the study was 67.9% in UH vs 84.7% in CC. Percentages of NMEnP in UH and CC were due respectively to cancellation by the patient (14.9 vs 7.4%), cancellation by the NMD (9.5 vs 3.4%), cancellation by the referring physician (5.1 vs 4.4%) and non-attender patients (2.7 vs 0.2%).

CONCLUSION

The study underlines the public health issue caused by COVID-19 above the pandemic itself and should be useful in preparing for potential resource utilisation and staffing requirements.

Increase of weight-bearing capacity of patients with lesions of the TFCC using a wrist brace

STUDY DESIGN

Retrospective cross-sectional case series.

BACKGROUND

Lesions of the triangular fibrocartilage complex (TFCC) can result in pain during axial load and unstable distal radioulnar joint (DRUJ). Conventional wrist orthoses decrease initial pain sufficiently but also prevent any movement during recovery and do not contribute to the stabilization of the DRUJ.

PURPOSE

In this retrospective analysis, we tested if the weight-bearing capacity of patients with lesions of the triangular fibrocartilage complex was increased by wearing a brace that stabilizes the distal radioulnar joint.

METHODS

Twenty-three patients had an arthroscopically confirmed TFCC lesion. We compared preoperative dynamic weight-bearing capacity of both hands with and without a commercially available wrist brace (WristWidget). Subgroup analysis was performed for stability of the distal radioulnar joint and etiology of the TFCC lesion. The dynamic ulnar variance was measured in a modified weight bearing test. We used parametric tests for normally distributed values.

RESULTS

The weight-bearing capacity of the hand with TFCC lesion was significantly lower than of the control hand (16 verus 36 kg; p <0.001). The relative load of the affected hand compared to the unaffected hand increased from 48 % (CI 37-60, SD 27) to 59 % (CI 47-72, SD 29 with a brace. The device had no effect on the control hand. Twelve patients with unstable DRUJ had a lower weight-bearing capacity compared to the eleven with stable joint. The percentage improvement with bracing was higher for those with unstable joints (versus stable) and traumatic lesions (versus degenrative).

CONCLUSION

The use of a wrist brace significantly increases the weight-bearing capacity and therefore the maximum tolerated axial load of patients with a lesion of the TFCC. Patients with traumatic lesion or unstable DRUJ tend to show lower values than with degenerative lesions or stable joints.

Das Fließgesetz vielkristalliner Metalle

Allgemeine lineare Gesetze für die Geschwindigkeit der plastischen Formänderung und für den Zusammenhang zwischen Spannung und Dehnung. — Bei isotropem Verfestigungszustand Inkremententheorie nach Prager. — Experimentelle Nachprüfung durch Zug-Torsions-Versuche mit beliebiger Drehung der Achsen des Spannungstensors. — Für Al Bestätigung der Pragerschen Formeln bis zu einer Dehnung von 9%. Dagegen für α-Messing Anisotropie des Verfestigungszustands. — Erklärung dieses Unterschieds aus Einkristallversuchen und aus der Theorie der Versetzungen.

Frontotemporale Demenz und delinquentes Verhalten

The nature and prevalence of misdemeanor in patients with dementia due to frontotemporal lobar degeneration has been described in a few case reports and in two small U.S. studies. Our clinical impression suggests that antisocial and aggressive behaviour are relatively frequent in this patient population. The objective of the present study was to verify this observation. For this purpose we developed a standardized questionnaire on misdemeanor in Frontotemporal Dementia. Using this instrument caregivers of 30 patients with Frontotemporal Dementia (FTD), 11 patients with Semantic dementia (SD) and 33 patients with Alzheimer-type dementia (AD) were interviewed. The interview included questions about theft, burglary, damaging other peoples' belongings, verbal or physical offence, bodily harm, drug abuse and use of weapons. Questions about the frequency of criminal behaviour, the amount of damages and consequences if applicable completed the questionnaire. Misdemeanor was found in half of the patients with FTD (15 out of 30) and in 7 out of 11 patients with SD, but only in one out of 33 patients with AD. The most frequent type of inappropriate behaviour was theft (13 patients), particularly shoplifting. 8 patients with FTD, 1 patient with SD and 1 patient with AD entered someone else's house without permission. 10 patients with FTD and 3 patients with SD but none of the patients with AD had physically threatened spouses, relatives or strangers. In one case another person was hurt.

[Efficacy of caregiver support groups for dementia]

Counseling of caregivers is an essential component of the management of patients with dementia. According to the empirical research in this field, peer-led self-help groups have the potential to improve subjective outcomes including emotional support, social contact, and control over one's life and thus may facilitate caregiving and reduce psychological burdens. Self-help groups have not been shown, however, to modify objective outcomes such as the time spent for care or the frequency of nursing home admissions. The outcomes of counseling programmes led by professionals depend on the focus of intervention and may include benefits in psychological and psychosomatic symptoms, coping with stress, and managing behavioural disturbances. Studies in the U.S., Australia, and Finland have demonstrated that multimodal counseling programmes led by professionals significantly reduce the number of nursing home admissions and therefore may have considerable importance for health economics.

Frontotemporal dementia, semantic dementia, and Alzheimer's disease: the contribution of standard neuropsychological tests to differential diagnosis

CERAD-NAB (Consortium to Establish a Registry for Alzheimer's Disease-Neuropsychological Assessment Battery) data were compared between 51 patients with frontotemporal dementia, 13 with semantic dementia, and 69 with Alzheimer's disease. There were statistically significant differences between the 3 groups. Compared with patients with Alzheimer's disease, patients with frontotemporal dementia were more impaired on Animal Fluency but not on any other CERAD-NAB subtest. Patients with semantic dementia performed worse in Animal Fluency and Boston Naming Test compared with frontotemporal dementia and Alzheimer's disease. Multiple logistic regression analysis revealed that in the differentiation between frontotemporal dementia and Alzheimer's disease, the combination of Animal Fluency and Boston Naming Test correctly classified 90.5% of patients. In segregating semantic dementia and Alzheimer's disease, the combination of Boston Naming Test and Mini Mental State Examination resulted in a correct classification of 96.3%. These findings demonstrate that the Mini Mental State Examination and the language subtests of the CERAD-NAB are valuable clinical instruments for the differential diagnosis between early frontotemporal dementia, semantic dementia, and Alzheimer's disease.

Association analysis of genes involved in cholesterol metabolism located within the linkage region on chromosome 10 and Alzheimer's disease

Epidemiological studies identified a higher risk of developing Alzheimer's disease (AD) among subjects with elevated cholesterol levels. This association may be caused by a modulation of the amyloid precursor protein (APP) processing in response to the cellular cholesterol content. High cholesterol levels may favor the amyloidogenic pathway by inhibition of the alpha-secretase probably leading to elevated beta-Amyloid (Abeta) production. The identification of a linkage peak on chromosome 10q using high Abeta as quantitative trait led us to examine polymorphisms of genes located on chromosome 10 involved in cholesterol metabolism, like Lipase A (LIPA), Cholesterol 25 hydroxylase (CH25H), and FLJ22476, a high density lipoprotein binding related protein. Using 286 patients with AD and 162 controls we analyzed several single nucleotide polymorphisms (SNPs) within LIPA, CH25H, and FLJ22476. None of the polymorphisms showed significant association with AD which contradicts recent findings on CH25H. From our results we conclude that the investigated genetic variations do not contribute to the genetic risk of AD.

Cerebral metabolic patterns at early stages of frontotemporal dementia and semantic dementia. A PET study

OBJECTIVE

To determine the patterns of cerebral glucose metabolism in frontotemporal dementia (FTD) and semantic dementia (SD).

METHODS

25 patients with mild FTD and 9 patients with mild SD as well as 15 healthy age-matched control subjects underwent 18F-FDG- positron emission tomography. Patient scans were compared with control scans using SPM-99.

RESULTS

As compared with healthy control subjects patients with FTD showed an extensive symmetrical hypometabolism of the frontal lobes (height threshold P <0.01) which spared the motor cortex. Patients with SD showed a hypometabolism in the whole left temporal lobe and in the right temporal pole.

CONCLUSIONS

In the clinical syndromes of FTD and SD two distinct patterns of cerebral metabolism were identified. FTD was associated with frontal hypometabolism, whereas in SD cerebral glucose metabolism was exclusively reduced in the temporal lobes. Our findings are consistent with the notion that FTD and SD begin as strictly lobar neuronal degenerations and that a spread of pathological changes is not seen until more advanced stages.

Region-specific decline of cerebral glucose metabolism in patients with frontotemporal dementia: a prospective 18F-FDG-PET study

OBJECTIVE

The aim of this study was to examine the pattern of glucose uptake and the changes over time of metabolic deficits in patients with frontotemporal dementia (FTD).

METHODS

10 patients who had received the clinical diagnosis of FTD underwent positron emission tomography scanning at the time of their first examination (baseline) and at follow-up (after 17.1 +/- 6.0 months). For statistical analysis, we used the SPM 99 software. First, we compared the data of the patients at baseline with an age-matched healthy control group. Second, we compared glucose uptake at follow-up with baseline measurements.

RESULTS

Compared with normal controls, FTD patients showed significant metabolic deficits primarily in frontal cortical areas, but also in the caudate nuclei and the thalami. At follow-up, a significant progression of metabolic deficit was exclusively observed in the orbitofrontal parts of the frontal lobe and in the subcortical structures.

DISCUSSION

These findings demonstrate that the clinical progression in patients with FTD is accompanied by a region-specific decline in cerebral glucose metabolism.

Leichte kognitive St�rung

The syndrome of mild cognitive impairment (MCI) is heterogeneous in terms of aetiology, psychopathology, and prognosis. It is characterised by cognitive deterioration significantly exceeding the decline attributable to aging but not reaching the severity of dementia. The prevalence of MCI is estimated to be 17% in the population over 65 years old. At neuropathological examination, a large proportion of patients with mild cognitive impairment, particularly of the amnestic type, show typical features of Alzheimer's disease. The former progresses to dementia at an annual rate of 10% to 15%. In some cases, however, there is stable impairment or remission. The neurodegenerative process of Alzheimer's disease can be demonstrated in at least some patients using volumetric magnetic resonance imaging, 18-FDG positron emission tomography, or biochemical markers in the cerebrospinal fluid. It is not yet known whether patients with mild cognitive impairment or at least those with predementia Alzheimer's disease can benefit from currently available symptomatic treatments. Patients with early-stage Alzheimer's are an important target group for treatment interventions aiming at slowing the neurodegenerative process.

[Frontotemporal dementia. Results from "Frontotemporal Demential and Pick's Disease Conference"]

At the Frontotemporal Dementia and Pick's Disease Conference, recent data concerning the epidemiology, diagnosis, and therapy of frontotemporal dementia were presented. Topics included clinical manifestations, differential diagnosis, pathologic and genetic bases of the disease, therapy, and specific problems facing patients and care givers. A consensus in the terminology of this condition was sought.

Lack of association between a single nucleotide polymorphism within the choline acetyltransferase gene and patients with Alzheimer's disease

Alterations of the cholinergic system may account for typical clinical and pathophysiological disturbances of Alzheimer's disease (AD). In particular, a marked decline of choline acetyltransferase activity (CHAT) and as a consequence of acetylcholine during the course of the disease has been described. Due to the chromosomal localization of CHAT at 10q11.23 and its possible role in the pathophysiology of AD, CHAT may represent an appropriate candidate gene conferring risk to AD. In fact, a recent study identified a functional single nucleotide polymorphism (SNP) within the first common exon of CHAT, which was associated with AD giving an odds ratio of 3.8 (Neurosci. Lett. 333 (2002) 9). Because of the potential importance of this finding we analyzed this SNP and another functional SNP within exon 9 (rs868749) of the CHAT gene using a German case control sample consisting of 242 patients with AD and 143 cognitively healthy controls. No statistically significant differences were obtained for the previously described polymorphism. In addition, the exon 9 SNP (rs868749) was not polymorphic in the studied population. We conclude that the previously identified polymorphism is not associated with AD.

[German-speaking memory clinics: state of the art and practical recommendations]

The 7th annual meeting of the memory clinics of Germany, Switzerland and Austria in March 2002 in Göttingen, Germany was an optimal opportunity to make an inventory about the state of the art in diagnostic and therapy of dementia and mild cognitive impairment in German-speaking memory clinics. Several problems were discussed including difficulties in 1) diagnosis of patients with aphasia or foreign patients, 2) handling of demented patients without a caregiver, 3) psychological support for patients, who have been diagnosed in a very early stage, 4) misunderstandings between general practitioners, neurologists and psychiatrists in private practice on the one hand and the memory clinics on the other hand, 5) recommendations for prevention of dementia, 6) recommendations concerning dementia and car driving and 7) questions of genetic counselling. The following paper is a summary of the results of a workshop in Göttingen and gives practical recommendations based on the experiences of the memory clinics.

[Features of frontotemporal dementia from the perspective of a special family support group]

Eight spouses of patients diagnosed with frontotemporal dementia (FTD) participated in a special support group. Seven weekly sessions of 90-min duration were held. This pilot project provided the opportunity to learn more about FTD and the specific problems and needs of caregivers. Their problems are predominantly due to changes in the patients' personalities and behaviour, not to the cognitive impairment. Furthermore, in contrast to Alzheimer's disease, patients are relatively young, the current state of scientific knowledge about FTD is unsatisfactory, and the disease is almost unknown among physicians. As part of the group activity, caregivers received information on the typical symptoms of FTD. This enhanced their understanding of the alterations in the patients' personalities and behaviour and facilitated acceptance of the disease. During group meetings, participants were encouraged to express their own needs and to deal with painful emotions including aggression, anger, mourning, and guilt. The caregivers felt relieved by sharing their problems with others. They were able to learn from each other and to exchange suggestions and solutions. The group also helped to establish new contacts and friendships. Participants' evaluations of the novel intervention were very positive. We conclude from these initial observations that support groups are needed for caregivers of patients with FTD which are tailored to their specific needs.

A polymorphism of the brain-derived neurotrophic factor (BDNF) is associated with Alzheimer's disease in patients lacking the Apolipoprotein E epsilon4 allele

Because of its implication in neuroprotection, formation of long lasting memories and a disturbed function in Alzheimer's disease (AD), brain-derived neurotrophic factor (BDNF) may represent an appropriate candidate gene conferring risk to AD. Recently, a single nucleotide polymorphism (C-270T) within the BDNF gene has been associated with late onset AD in a Japanese population giving an odds ratio (OR) of 3.8. Because of the importance of this finding we analysed the BDNF polymorphism in a German sample consisting of 210 patients with AD and 188 cognitively healthy controls. The T-allele frequency was higher in patients with AD (11.9%) compared to controls (6.9%) (P = 0.035; OR = 2.26; 95% CI: 1.04-4.48). The risk conferred by the T-allele was stronger in patients who lack the ApoE epsilon4 allele giving an OR of 2.61 (1.21-5.64) P = 0.015, particularly in patients with early onset of the disease; OR 3.13 (1.32-7.43); P= 0.01. Due to the small number of patients showing both, lack of the ApoE epsilon4 allele and the BDNF T allele (n = 18), the result needs to be confirmed in a larger sample. The results suggest that the BDNF C-270T polymorphism is a relevant risk factor for AD particularly in patients lacking the ApoE epsilon4 allele in this German sample.

Cerebrospinal fluid tau and beta-amyloid 42 proteins identify Alzheimer disease in subjects with mild cognitive impairment

CONTEXT

Cerebrospinal fluid tau protein and beta-amyloid 42 (Abeta42) protein are altered even in very mild Alzheimer disease (AD). So far, few data exist for subjects with mild cognitive impairment (MCI).

OBJECTIVE

To investigate the potential of cerebrospinal fluid tau and Abeta42 for predicting progression from MCI to AD in a longitudinal study of 28 patients with MCI who received follow-up for 18 months.

DESIGN

An 18-month prospective study.

SETTING

Clinical follow-up study of community-residing subjects with MCI.

MAIN OUTCOME MEASURES

Cerebrospinal fluid tau and Abeta42 concentrations were measured using enzyme-linked immunosorbent assay at baseline. The potential of both biomarkers was evaluated to predict the progression to dementia, the end point of this study, using multiple logistic regression analysis.

RESULTS

Of 28 subjects with MCI, 12 progressed to dementia (2 to frontotemporal dementia; 10 to AD). Six subjects had progressive MCI, and 10 subjects showed stable MCI. Cerebrospinal fluid tau levels were significantly elevated in patients who progressed to probable AD (P =.002) and subjects with progressive MCI (P =.003) compared with subjects who had stable MCI. Cerebrospinal fluid Abeta42 levels were significantly lower in patients who progressed to probable AD (P =.007) and those with progressive MCI (P =.04) than in subjects with stable MCI. Logistic regression analysis identified elevated tau protein level as a predictor of cognitive deterioration (P =.02), whereas a delayed verbal recall score at baseline was significantly associated with the development of probable AD (P =.03).

CONCLUSION

Our results indicate that altered tau and Abeta42 concentrations may be detectable in subjects who are clinically diagnosed as having MCI but demonstrate the pathological changes of AD.

Frontotemporal dementia: patient characteristics, cognition, and behaviour

OBJECTIVES

To describe sociodemographic data of patients with frontotemporal dementia (FTD), to compare the cognitive profile of patients with FTD with that of severity-matched patients with Alzheimer's disease using the CERAD neuropsychological battery (CERAD-NP), to investigate the frequency of behavioural disturbances, and to examine the relation between FTD-specific non-cognitive behavioural symptoms of patients with FTD with age and sex.

METHODS

Fifty outpatients were diagnosed with FTD according to the Lund-Manchester consensus criteria. Cognitive impairment was assessed in 30 patients using the CERAD-NP. Severity of dementia was rated on the Clinical Dementia Rating (CDR). Eleven non-cognitive symptoms were rated by severity. To compare CERAD-NP results between patients with FTD and AD, 30 patients with AD were matched for age, sex, and global severity of cognitive performance.

RESULTS

The average age at onset of first symptoms was 57.8 years. Eighteen patients (36%) had a positive family history of dementia. On the CERAD-NP patients with FTD performed significantly better than patients with AD on word list learning, delayed verbal recall and visuoconstruction (p < 0.05). There were no significant differences between FTD and AD on naming and verbal fluency tasks. The most frequent non-cognitive behavioural symptoms in FTD were loss of insight, speech abnormality, and apathy. Non-cognitive behavioural symptoms were more frequent in younger and in male than in older patients and in female patients.

CONCLUSIONS

The CERAD-NP is a valuable clinical instrument for the cognitive evaluation of patients with suspected FTD. Complementary short tests of attention and executive function may be recommended. To enhance diagnostic sensitivity informant interviews should focus on non-cognitive behavioural changes, taking advantage of standardised questionnaires.

Tau and Abeta42 protein in CSF of patients with frontotemporal degeneration

BACKGROUND

CSF concentrations of tau and beta-amyloid protein-42 (Abeta42) have been extensively studied in AD. Few data are available concerning CSF levels of both proteins in patients with frontotemporal degeneration (FTD).

METHODS

The authors investigated CSF tau and Abeta42 concentrations in 34 patients with FTD, 74 patients with AD, and 40 cognitively healthy control subjects. CSF levels of tau and Abeta42 were measured by ELISA. With use of receiver operating characteristic-derived cutoff points and linear discrimination lines, the diagnostic sensitivity and specificity of both markers were determined.

RESULTS

CSF tau concentrations were significantly higher in FTD than in control subjects but were significantly lower than in AD. CSF Abeta42 levels were significantly lower in FTD than in control subjects but were significantly higher than in AD. In subjects with FTD, neither tau nor Abeta42 levels correlated with the severity of dementia. The best discrimination between the diagnostic groups was obtained by simultaneous measurement of tau and Abeta42, yielding a sensitivity of 90% at a specificity of 77% (FTD vs controls) and a sensitivity of 85% at a specificity of 85% (FTD vs AD).

CONCLUSIONS

In FTD, CSF levels of tau are elevated and Abeta42 levels are decreased. With use of these markers, subjects with FTD can be distinguished from control subjects and from patients with AD with reasonable accuracy.

Apolipoprotein E polymorphism in German patients with frontotemporal degeneration

OBJECTIVES

The apolipoprotein E (apoE) polymorphism, designated as epsilon2, epsilon3, epsilon4, is a genetic risk factor associated with several forms of dementia. Inconclusive results have been reported in patients with frontotemporal degeneration which prompted this study of the apoE polymorphism in a German sample with frontotemporal degeneration.

METHODS

the frequencies of the epsilon2 and epsilon4 alleles and the effect of these alleles on the age at onset in 52 patients with frontotemporal degeneration who underwent a thorough diagnostic examination and in 182 cognitively healthy age matched controls were assessed. Genotype comparisons between the groups were performed using multiple logistic regression analysis. Ages at onset according to the apoE genotype were compared by linear regression analysis.

RESULTS

In patients with frontotemporal degeneration apoE epsilon2 and epsilon4 allele frequencies were 9.6% each, whereas the corresponding frequencies in controls were 9.6% and 9.9%, respectively. There was no significant difference in either epsilon2 or epsilon4 allele frequency between the groups. Age at onset was highest in patients with the epsilon2/epsilon3 genotype (61.3 years) followed by patients with the epsilon3/epsilon3 (58.3 years) and was lowest in patients with the epsilon3/epsilon4 genotype (56.4 years) but the differences failed to reach statistical significance.

CONCLUSION

Allelic variants of the apoE gene do not modulate occurrence or age at onset in this sample of German patients with frontotemporal degeneration.

Non-local Concepts and Models in Biology

In this paper, we consider local and non-local spatially explicit mathematical models for biological phenomena. We show that, when rate differences between fast and slow local dynamics are great enough, non-local models are adequate simplifications of local models. Non-local models thus avoid describing fast processes in mechanistic detail, instead describing the effects of fast processes on slower ones. As a consequence, non-local models are helpful to biologists because they describe biological systems on scales that are convenient to observation, data collection, and insight. We illustrate these arguments by comparing local and non-local models for the aggregation of hypothetical organisms, and we support theoretical ideas with concrete examples from cell biology and animal behavior.

Gingival reaction on crowns with cast and sintered metal margins: a progressive report

Sintered metals have been developed recently for the construction of metal ceramic crowns (Degusint U). An unbalanced, randomized double-blind study was conducted to compare the gingival response to artificial crowns with sintered noble metal margins and cast noble metal margins (Degudent U) by measuring the sulcus-fluid-flow rate (SFFR) in highly motivated patients. In a prior study marginal opening of 20 microns were recorded for cast metal crowns, whereas two sintered metal crowns had marginal openings of 40 microns. Three metal ceramic crowns (Renaissance, Degusint U, and Degudent U for the copings and VMK 68 porcelain) with subgingival margins were prepared and fabricated for 12 intact natural teeth. The SFFR was measured for teeth with artificial crowns and adjacent natural teeth after provisional insertion of each crown. Significantly elevated SFFRs were recorded for all artificial crowns compared with the adjacent natural teeth, but there were no variations recorded for the different types of crown margins.

Left ventricular diastolic collapse in regional left heart cardiac tamponade. An experimental echocardiographic and hemodynamic study

OBJECTIVES

This study was designed to describe the hemodynamic abnormalities associated with the appearance of left ventricular diastolic collapse in the setting of regional left heart cardiac tamponade.

BACKGROUND

Cardiac tamponade after heart surgery is frequently associated with localized pericardial effusion. Although right ventricular diastolic collapse and right atrial collapse are reliable echocardiographic findings in patients with circumferential pericardial effusion and tamponade, they are often not present in postoperative patients with localized pericardial effusion and regional left heart tamponade. Left ventricular diastolic collapse has been described in such patients, but the degree of hemodynamic alteration that exists with this finding is not known.

METHODS

Acute regional left heart tamponade was produced 14 times in seven spontaneously breathing anesthetized dogs by infusing fluid into an isolated compartment created in the pericardial space adjacent to the left ventricular free wall. Continuous echocardiographic imaging and hemodynamic monitoring of left ventricular, systemic arterial, right atrial, pulmonary capillary wedge and pericardial pressures were performed. Measurements at baseline were compared with those made at the onset of left ventricular diastolic collapse and at decompensated tamponade.

RESULTS

Left ventricular diastolic collapse was noted in all 14 episodes of regional tamponade. It occurred when pressure in the left pericardial compartment exceeded left ventricular diastolic pressure by 3.0 +/- 1.9 mm Hg. At the onset of left ventricular diastolic collapse, cardiac output and mean arterial pressure were significantly reduced from the control value (p < 0.05). Systolic hypotension was noted only twice at this stage, respiratory variation in systolic pressure > 10 mm Hg only once. The appearance of this sign was also associated with elevated left heart filling pressures.

CONCLUSIONS

Left ventricular diastolic collapse is a reliable sign of regional left ventricular tamponade and is associated with a reduction in cardiac output. This echocardiographic finding usually occurs before the development of arterial hypotension and pulsus paradoxus. Thus, left ventricular diastolic collapse is potentially more reliable than hypotension or pulsus paradoxus in the diagnosis of regional left ventricular tamponade.

Divergent hemodynamic and hormonal responses to varying salt intake in normotensive subjects

Blood pressure responses to 1 week of low-salt (20 mmol sodium/d) and high-salt (300 mmol sodium/d) intake were investigated in a single-blind randomized study in 163 white, nonobese normotensive subjects (65 women and 98 men; mean age, 38 +/- 1.2 years). The individuals were classified as salt sensitive when mean arterial blood pressure rose by at least 5 mm Hg during high-salt intake, as salt resistant when mean arterial blood pressure changed by less than 5 mm Hg, and as "counterregulator" when mean arterial blood pressure fell by at least 5 mm Hg during the high-salt diet. Reexamination of 31 subjects showed that this approach to the testing of salt sensitivity was reliable and reproducible. Thirty subjects (18.4%) were classified as salt sensitive, 108 (66.3%) as salt resistant, and 25 (15.3%) as counterregulators. Multiple regression analysis revealed that age, body weight, and family history of hypertension contributed significantly to the change in blood pressure after the diets. Salt sensitivity was more frequent in older subjects and in those with a positive family history of hypertension. An increase in blood pressure after salt restriction was more likely in younger individuals and in those with a negative family history of hypertension. Plasma renin activity and plasma aldosterone concentrations were lower in salt-sensitive compared with salt-resistant and counterregulating subjects. The rise in plasma renin activity during salt restriction was most pronounced in counterregulating subjects. Plasma norepinephrine concentrations were not different among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Transesophageal echocardiography for hemodynamic management of thoracoabdominal aneurysm repair

Maintenance of cardiovascular stability during thoracoabdominal aneurysm repair remains a formidable challenge. Transesophageal echocardiography (TEE) has been shown to be an excellent method for detecting myocardial ischemia and assessing left ventricular volume. We examined the utility of TEE in a group of 17 patients from an overall series of 33 patients who underwent thoracoabdominal aneurysm resection between 1988 and 1992. The mortality rate was 9%, whereas the incidences of myocardial infarction and paraplegia were 13% and 6%, respectively. Intraoperative management was significantly altered by TEE data in nine patients. Two patients were noted to have mitral valve insufficiency, and one had transient ischemia-induced regional wall abnormalities. In six patients, Swan-Ganz-derived filling data failed to identify severe hemodynamic alterations that were noted on TEE. Five patients were hypovolemic and hyperdynamic, whereas one was in florid congestive heart failure. Further investigation is warranted to prospectively validate this technique.

Slip-casting alumina ceramics for crown and bridge restorations

The In-Ceram technique uses alumina ceramics and glass in a two-step firing procedure to create a high-strength core material for single-tooth restorations as well as small fixed partial dentures. Fine-grain alumina particles are sintered to form a porous substructure, which is infiltrated with molten glass. The combination of these two processes gives the material its outstanding properties. The sintering process is almost without shrinkage, providing an excellent fit, while the glass infiltration leaves practically no porosities, resulting in high strength.

Chronic kappa-opioid receptor antagonism delays the rise in blood pressure in spontaneously hypertensive rats

A 4-week subcutaneous treatment with the kappa-opioid receptor antagonists, MR 2266 or MR 1452, delayed the age-dependent increase in systolic blood pressure in young spontaneously hypertensive rats (SHR), but not in normotensive rats. The content of beta-endorphin, [Leu5]enkephalin, and catecholamines in various brain tissues was not affected by MR 2266. Specificity of the kappa-opioid receptor antagonism was tested in SHR by injection of the kappa-opioid agonist, MR 2033, and the mu agonist, morphiceptin, after 28 days of MR 1452 or saline and 2 days after the end of treatment. The increase in mean arterial blood pressure (MAP) after MR 2033 did not differ between the two groups at the 28th day of treatment but was higher 2 days later in the previous MR 1452 group, possibly indicating up-regulation of kappa-opioid receptors. Morphiceptin did not alter MAP during or after MR 1452. It is concluded that kappa-opioid receptors may have a tonic influence on the age-dependent increase of blood pressure in SHR but not in normotensive rats.

Influence of chronic opioid delta receptor antagonism on blood pressure development and tissue contents of catecholamines and endogenous opioids in spontaneously hypertensive rats

Opioid delta receptors seem to be involved in blood pressure regulation of spontaneously hypertensive rats (SHR), possibly by an interaction with the sympathetic nervous system. In the present study the effect of four weeks' chronic delta receptor antagonism with ICI 154 129 on development of blood pressure was evaluated in young SHR. Contents of adrenaline and noradrenaline and the opioid peptides beta-endorphin and leucine-enkephalin were measured in brain stem, mid brain, hypothalamus, and adrenal glands. After four weeks' treatment, systolic blood pressure was lower when compared with control SHR. During chronic delta antagonism, concentrations of adrenaline were higher in hypothalamus, mid brain and adrenal glands, contents of noradrenaline were higher in hypothalamus and adrenal glands than in control rats, contents of opioid peptides were not altered with the exception of an increase of beta-endorphin concentration in the hypothalamus. The changes in concentrations of catecholamines following chronic delta antagonism may reflect an alteration of sympathetic activity and could contribute to the retardation of blood pressure development.

[First clinical and materials experience with full porcelain crowns and In-Ceram bridge system]

The all-ceramic crown- and bridge-system In-Ceram uses a glass-infiltrated, sintered alumina-ceramic core material. The construction of bridges seems to be possible due to the high bending strength of the core material. The results concerning marginal fit and aesthetics are very pleasing. However, long-term results with this material are not available.

Recurrent medulloblastoma: frequency of tumor enhancement on Gd-DTPA MR imaging

Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor.

Recurrent medulloblastoma: frequency of tumor enhancement on Gd-DTPA MR imaging

Thirty-two children with medulloblastoma were evaluated postoperatively with conventional and gadolinium-enhanced MR imaging. Eleven patients had abnormal cranial MR studies; nine of these had recurrent tumor. In six patients recurrent tumor enhanced with Gd, while in the other three patients recurrent tumor did not enhance. The remaining two patients had areas of abnormal Gd enhancement that were caused by radiation-induced breakdown of the blood-brain barrier rather than by recurrent tumor. This study shows that not all recurrent medulloblastoma enhances and that the absence of Gd enhancement does not necessarily indicate the absence of recurrent tumor.

Altered plasma leucine-enkephalin concentrations in patients with established hypertension may be involved in impaired regulation of blood pressure

Leucine-enkephalin is known to modulate cardiovascular activity. In the present study we determined plasma leucine-enkephalin and noradrenaline concentrations in young men with essential hypertension and in normotensives at rest and after bicycle exercise. The essential hypertensive patients had a lower concentration level of resting leucine-enkephalin than the normotensives. Exercise increased leucine-enkephalin in both groups. Noradrenaline was significantly higher in the essential hypertensives than in the normotensives. The central alpha 2-agonist clonidine reduced leucine-enkephalin at rest in the normotensives and prevented its increase during exercise, but had no effect on leucine-enkephalin in the essential hypertensives. These results may reflect an altered interaction between leucine-enkephalin and noradrenaline in essential hypertensives compared to normotensives, possibly contributing to hypertension.

The marginal fit of cemented galvanoceramic crowns

Galvanoceramic restorations were constructed for five extracted teeth. Following cementation, the margins were photographed (magnification X 33) and the prints mounted to produce a continuous image of the entire margin. Cement film thickness measurements were made at 0.1-mm intervals. The five cemented restorations were then embedded in resin, sectioned longitudinally, and examined under a microscope (X 125). The mean gap at the restoration margin, as measured by each technique, was 18 microns and 19 microns, respectively. These results were consistent with the clinical impressions of cemented galvanoceramic restorations completed at the University of Tübingen.