Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child

Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs.     

Synthese von 2-Carbazoylthio-essigsäuren und deren Cyclisierung zu 3-Amino-thiazolidin-2,4-dionen

Synthesis of 2-(Hydrazinocarbonylthio)-acetic Acids and Cyclization to 3-Aminothiazolidine-2,4-diones N-mono- or N,N-disubstituted hydrazines are reacted with carbonyl sulfide, triethylamine and halogenoacetic acids to yield the 2-(hydrazinocarbonylthio) acetic acids 1 , which are cyclizised to yield the 3-aminothiazolidine-2,4-diones 2 by dicyclohexylcarbodiimide.     

Direct measurement of resultant forces in the anterior cruciate ligament. An in vitro study performed with a new experimental technique

A new technique was used to measure the resultant forces in the anterior cruciate ligament during a series of loading experiments on seventeen fresh-frozen cadaver specimens. The base of the ligament's tibial attachment was mechanically isolated with a coring cutter, and a specially designed load-transducer was fixed to the bone-plug that contained the ligament's tibial insertion so that the resultant forces were directly measured by the load-cell. Although the magnitudes of values for forces varied considerably between specimens for a given test condition, the patterns of loading with respect to direction of loading and the angle of flexion of the knee were remarkably consistent. Passive extension of the knee generated forces in the ligament only during the last 10 degrees of extension; at 5 degrees of hyperextension, the forces ranged from fifty to 240 newtons (mean, 118 newtons). When a 200-newton pull of the quadriceps tendon was applied to extend a knee slowly against tibial resistance, however, the force in the ligament increased at all angles of flexion of the knee. Internal tibial torque always generated greater forces in the ligament than did external tibial torque; higher forces were recorded as the knee was extended. The greatest forces (133 to 370 newtons) were generated when ten newton-meters of internal tibial torque was applied to a hyperextended knee. Fifteen newton-meters of applied varus moment generated forces of ninety-four to 177 newtons at full extension; fifteen newton-meters of applied valgus moment generated a mean force of fifty-six newtons, which remained unchanged with flexion of the knee. The force during straight anterior translation of the tibia was approximately equal to the anterior force applied to the tibia. The application of 925 newtons of tibiofemoral contact force reduced the mean force in the ligament that was generated by 200 newtons of anterior pull on the tibia by 36 per cent at full extension and 46 per cent at 20 degrees of flexion.     

Strength of initial mechanical fixation of screw ring acetabular components

This study was conducted to determine the effects of design on the initial fixation of several types of screw-ring acetabular components. The components were tested in polyurethane foam to assess relative screw fixation strengths with a consistent material. Embalmed pelves from anatomic specimens were used to conduct paired tests between designs that showed large differences in insertional torque to failure in foam. The quality of the initial fixation in foam was found to be dependent on the design features of the components. Components with widely spaced, deep threads, and minimal thread interruptions offered the strongest initial fixation in foam. Tests in bone revealed a wide range of fixation strengths reflecting the variability in bone quality. No differences in fixation strength attributable to component design were observed in bone. When the insertional failure torque was greater than 60 N.m, one-half of the pelves fractured, and these fractures occurred with all designs. At failure torques less than 60 N.m, failure was predominantly due to thread strippage of the screw, with only two of 20 specimens experiencing pelvic fracture.     

Proton NMR spectroscopy of cerebral metabolic alterations in infantile peroxisomal disorders.

Noninvasive studies of cerebral metabolism were performed with use of localized proton MR spectroscopy (MRS) in both healthy controls (n = 4, age 6 weeks to 2 years) and infants (n = 4, age 3-15 months) who had impaired peroxisomal functions classified as variants of Zellweger syndrome. All patients revealed a marked decrease of N-acetylaspartate in white and gray matter, thalamus, and cerebellum, indicating impairment of normal neuronal development as well as neuronal loss. In two cases an increase of cerebral glutamine and a decrease of the cytosolic polyol myo-inositol in gray matter and striatum reflected the impact of a concomitant effect on hepatic function. Two cases 3 and 6 months of age exhibited a notable elevation of mobile lipids and/or cholesterol in white matter. These patients with severe disease died within 4 weeks after the MRS examination. While an increase of free fatty acids generally associated with a lysosomal storage disease was not consistently observed by proton MRS of brain, this technique provides a convenient and safe tool for the direct assessment of neuropathologic aspects of Zellweger syndrome such as neuronal degeneration, demyelination, and consequences of compromised liver function.     

The impact of non-pharmaceutical interventions on COVID-19 epidemic growth in the 37 OECD member states

We estimated the impact of a comprehensive set of non-pharmeceutical interventions on the COVID-19 epidemic growth rate across the 37 member states of the Organisation for Economic Co-operation and Development during the early phase of the COVID-19 pandemic and between October and December 2020. For this task, we conducted a data-driven, longitudinal analysis using a multilevel modelling approach with both maximum likelihood and Bayesian estimation. We found that during the early phase of the epidemic: implementing restrictions on gatherings of more than 100 people, between 11 and 100 people, and 10 people or less was associated with a respective average reduction of 2.58%, 2.78% and 2.81% in the daily growth rate in weekly confirmed cases; requiring closing for some sectors or for all but essential workplaces with an average reduction of 1.51% and 1.78%; requiring closing of some school levels or all school levels with an average reduction of 1.12% or 1.65%; recommending mask wearing with an average reduction of 0.45%, requiring mask wearing country-wide in specific public spaces or in specific geographical areas within the country with an average reduction of 0.44%, requiring mask-wearing country-wide in all public places or all public places where social distancing is not possible with an average reduction of 0.96%; and number of tests per thousand population with an average reduction of 0.02% per unit increase. Between October and December 2020 work closing requirements and testing policy were significant predictors of the epidemic growth rate. These findings provide evidence to support policy decision-making regarding which NPIs to implement to control the spread of the COVID-19 pandemic.

     

Quantitative proton magnetic resonance spectroscopy of cerebral metabolic disturbances in patients with MELAS

Four patients with clinically and genetically defined MELAS were examined using quantitative localized proton magnetic resonance spectroscopy of the brain. Acute and chronic lesions were located in the occipital lobe and mostly characterized by strongly elevated concentrations of lactate (Lac) and glucose (GIc) as well as severely reduced concentrations of total N-acetylaspartyl compounds (tNAA, neuroaxonal markers), glutamate (Glu), and total creatine. These findings indicate a high degree of nonoxidative glycolysis reflecting either impaired oxidative energy metabolism or the use of anaerobic metabolism by infiltrating macrophages as well as damage or loss of viable neuroaxonal tissue. In contrast, glial cell populations, in particular astrocytes, seem to remain unaffected as evidenced by unchanged concentrations of myo-inositol (glial marker). In addition, all patients including one who never experienced a stroke-like episode showed elevated Lac and Glc as well as reduced tNAA and Glu in tissues appearing normal on MRI. These disturbances were stronger in cortical gray matter and cerebellum than in white matter and indicate that neuroaxonal damage is not restricted to structural lesions. The steady presence of Lac is consistent with a reduced capacity of the mitochondrial oxidative energy metabolism resulting from impaired respiratory chain function.     

Foix-Chavany-Marie (anterior operculum) syndrome in childhood: a reappraisal of Worster-Drought syndrome

Foix-Chavany-Marie syndrome (FCMS) is a distinct clinical picture of suprabulbar (pseudobulbar) palsy due to bilateral anterior opercular lesions. Symptoms include anarthria/severe dysarthria and loss of voluntary muscular functions of the face and tongue, and problems with mastication and swallowing with preservation of reflex and autonomic functions. FCMS may be congenital or acquired as well as persistent or intermittent. The aetiology is heterogeneous; vascular events in adulthood, nearly exclusively affecting adults who experience multiple subsequent strokes; CNS infections; bilateral dysgenesis of the perisylvian region; and epileptic disorders. Of the six cases reported here, three children had FCMS as the result of meningoencephalitis, two children had FCMS due to a congenital bilateral perisylvian syndrome, and one child had intermittent FCMS due to an atypical benign partial epilepsy with partial status epilepticus. The congenital dysgenetic type of FCMS and its functional epileptogenic variant share clinical and EEG features suggesting a common pathogenesis. Consequently, an increased vulnerability of the perisylvian region to adverse events in utero is discussed. In honour of Worster-Drought, who described the clinical entity in children 40 years ago, the term Worster-Drought syndrome is proposed for this unique disorder in children.     

Hyperlipidämie und Fibrate unter besonderer Berücksichtigung des Diabetes

The lipid triad: hypertriglyceridemia, low HDL, small dense LDL represents a high risk group for excessive cardiovascular morbidity and mortality in type 2 diabetes. In poorly controlled diabetes LDL are increasingly oxydized and glycosylated whereas HDL degradation is accelerated. The high lipid risk in coincidence with the diseases of the metabolic syndrome leads to the conclusion that diabetes today is a cardiovascular disease demanding an aggressive correction of the lipid triad. The benefit of lipid lowering treatment has been proven not only for statins but there is more and more evidence also in favour of fibrates. Fibrates are particularly useful in the treatment of hypertriglyceridemia/low HDL. This also leads to a reduction in small dense LDL. In the case of insufficient correction of LDL a combination with a low dose of a statin is recommended. A definite answer with respect to the benefit/risk ratio of fibrates should be provided by large ongoing studies with these drugs in representative groups of diabetes patients (LDS, TrUMPET, FIELD).