Magnetic resonance images of 91 children with different causes of short stature: pituitary size reflects growth hormone secretion

In order to validate an association between pituitary size and severity of growth hormone deficiency (GHD) we evaluated the magnetic resonance images (MRI) of 107 children with different causes of short stature. Ninety-one MRIs were evaluable (64 male, 27 female; age: 9.1 +/- 3.9 years). The levels of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3), and tests of GH stimulation and spontaneous secretion, led to the following subgroups: severe isolated GHD (SIGHD) (GH < 7 ng/ml) (n = 21); partial, isolated GHD (GH 7-10 ng/ml) (n = 22); multiple pituitary hormone deficiency (MPHD) (n = 13); neurosecretory dysfunction (n = 10); non-classifiable diagnosis (NC) (n = 13); idiopathic short stature (n = 9); and intra-uterine growth retardation (n = 3). Pituitary height (PHT) was measured and hypoplasia was assumed when PHT was < -2 SDS. An ectopic posterior pituitary with missing stalk and a hypoplastic anterior pituitary was present in 12 (57%) SIGHD cases, 12 (92%) MPHD cases and 1 patient from the NC group. An isolated hypoplastic anterior pituitary was observed in 15%-33% of the other groups. PHT (mm; mean, SD) in MPHD (1.7 +/- 0.5) was lower than in SIGHD (2.7 +/- 1.0, P < 0.05), with PHT of both groups being lower than in all the other groups (3.8 +/- 0.9, P < 0.0001). PHT SDS correlates with IGF-I SDS (r = 0.48, P < 0.0001), IGFBP-3 SDS (r = 0.46, P < 0.0001) and the highest peaks in tests of GH stimulation and GH spontaneous secretion (r = 0.36, P < 0.0001). In contrast to all the other groups, no correlation with age was observed in MPHD and SIGHD. Breech delivery was recorded in up to 26% of patients in all seven groups. Surprisingly, only 1 out of 23 patients with an ectopic posterior pituitary was born by breech delivery, suggesting that ectopia of the posterior lobe is not necessarily related to breech delivery.

CONCLUSION

PHT is significantly correlated with GH secretion in several types of short stature. Patients with ectopic posterior pituitary, missing stalk and hypoplastic anterior pituitary either suffer from SIGHD or MPHD, and this anatomical defect is not necessarily related to breech delivery.

The importance of pial blood supply to the development of peritumoral brain edema in meningiomas

In a retrospective analysis, the authors studied the pial and dural blood supplies in 74 intracranial meningiomas and quantified their associated peritumoral brain edema (PTBE). The extent and localization of pial blush in relation to the total tumor volume were determined angiographically. The amount of edema and tumor size were calculated using computerized tomography. The edema-tumor volume ratio was defined as Edema Index (EI). There were 49 meningiomas with PTBE; of those tumors, 46 were supplied by pial vessels, and three were supplied exclusively by dural vessels. Tumors without PTBE showed no pial blush. The mean EI in meningiomas with pial blush was significantly larger (EI = 3) than in meningiomas without pial supply (EI = 1.1; p < 0.0001). Meningiomas with a smaller pial supply than dural supply had a significantly smaller mean EI than tumors with a pial supply equal to or greater than the dural supply (EI = 2.9 vs. EI = 3.7; p < 0.015). In 69.9% of cases with pial blood supply, major portions of the edema were located adjacent to the tumor region supplied by pial vessels. Edema index differences among tumors of different subgroups, as defined by size or histology, were significantly related to the pial supply in each subset. Thus, pial blood supply may be associated with the development of PTBE in meningiomas.

[Indications for contrast medium administration in MR-angiography of cerebral blood vessels]

Time-of-flight MR-angiography of large volumes is limited by the occurrence of saturation effects, which lead to low signal in both veins and arteries. Alternatively to a number of other MRA-techniques, intravenous application of paramagnetic contrast media in combination with 3D-pulse sequences with or without flow refocussing allows the depiction of slow vessels in large volumes without technical extra expenses. The main intracranial indication is anatomical 3D-imaging of normal and dysplastic cerebral veins with high spatial resolution, and the additional depiction of the venous drainage in AVMs, when unenhanced MRA shows only the arteriel supply and the nidus. In large cerebral aneurysms, bridging veins and venous sinuses, partial thromboses can easily be differentiated from slow flow. Contrast-enhancing tumors can be depicted together with normal or displaced vessels. Improvements of arterial signal due to contrast media with currently used routine MRA techniques are clinically not significant. Signal loss due to spin dephasing in vessels with complex flow is not influences by contrast media. Results of contrast-enhanced MRA are determined by the timing of injection. Since arteries and veins are both imaged with high signal intensity, improvements of postprocessing procedures for secondary vessel segmentation are necessary.

Deletion within the D17S34 locus in a primitive neuroectodermal tumor

Loss of heterozygosity on chromosome 17p13.3 is frequently observed in solid tumors, and the presence of a tumor suppressor gene has been predicted in this region of chromosome 17. We have analyzed a primitive neuroectodermal tumor sample exhibiting loss of heterozygosity at the D17S34 locus, a commonly used telomeric marker on the short arm of chromosome 17. The remaining allele showed a rearrangement. Cosmids spanning the D17S34 locus and probes from that region were used to demonstrate a 9-kb deletion within the D17S34 locus and were found to contain evolutionary, conserved sequences. Genetic alterations in this region may also affect expression of immediately adjacent genes, such as ABR, and could be a common mechanism in the causation of primitive neuroectodermal tumors.

Voluntary facial palsy with a pontine lesion

Images

Extended long-term culture reveals a highly quiescent and primitive human hematopoietic progenitor population

Long-term culture-initiating cells (LTC-IC) are hematopoietic progenitors able to generate colony-forming unit-cells (CFU) after 5 to 8 weeks (35 to 60 days) of culture on bone marrow (BM) stroma and represent the most primitive progenitors currently detectable in vitro. We have recently reported that long-term cultures initiated with CD34+CD38- cells from BM or cord blood are able to continue generating CFU for at least 100 days, ie, beyond the standard LTC-IC period. In this report, single-cell cultures from cord blood and retroviral marking of cord blood and BM were used to study whether the subpopulation of CD34+CD38- cells able to generate CFU beyond 60 days ("extended long-term culture-initiating cells" or ELTC-IC) are functionally distinct from LTC-IC in terms of timing of initial clonal proliferation and generative capacity. All cord blood LTC-IC formed clones of greater than 50 cells by day 30. In contrast, cord blood ELTC-IC proliferated later in culture, 50% forming clones after day 30. Although efficient retroviral marking of LTC-IC was seen (25% to 45%), marking of ELTC-IC was inefficient (< 1%), consistent with a more quiescent progenitor population. There was a positive correlation between time of clonal proliferation and generative capacity. ELTC-IC generated threefold to fourfold more progeny than did LTC-IC (P < .002). These studies show that there is a functional hierarchy of progenitors in long-term culture which correlates with their level of quiescence. By extending the LTC-IC assay, a more primitive progenitor may be studied that may be functionally closer to the human long-term repopulation stem cell in vivo.

Interobserver agreement in assessing early CT signs of middle cerebral artery infarction

PURPOSE

To assess the reliability of detecting signs of hemispheric infarction on CT scans obtained within 6 hours of the onset of symptoms.

METHODS

A neuroradiologist selected 12 normal and 33 abnormal CT studies showing the hyperdense middle cerebral artery sign (HMCAS) (n = 10), brain swelling (n = 22), and parenchymal hypodensity (n = 33) from two series of 750 patients with recent onset of middle cerebral artery stroke. These selections served as the reference source for a nonblinded analysis of the initial and follow-up CT scans. Six neuroradiologists then reviewed the CT scans twice, first blinded then not blinded to clinical symptoms. They assessed the signs of infarction for each hemisphere separately and estimated the volume of abnormal parenchymal hypodensity in increments of 20% within the territory of the middle cerebral artery.

RESULTS

Unblinding the reviewers did not change interobserver agreement significantly. The chance adjusted agreement was moderate to substantial: kappa = .62 (95% confidence interval [CI], .46 to .78) and kappa = .57 (95% CI, .33 to .81) for the HMCAS of the right and left hemisphere, respectively; kappa = .59 (95% CI, .47 to .71) and kappa = .56 (95% CI, .38 to .74) for focal brain swelling of the right and left hemisphere, respectively; and kappa = .58 (95% CI, .50 to .66) and kappa = .55 (95% CI, .32 to .67) for parenchymal hypodensity of the right and left hemisphere, respectively. Weighted kappa was .65 and .57 for the estimation of the hypodense tissue volume in the right and left hemisphere, respectively. Agreement with the reference source ranged from 73% to 93% for all variables and both hemispheres.

CONCLUSION

Even with no clinical information, neuroradiologists can assess subtle CT signs of cerebral infarction within the first 6 hours of symptom onset with moderate to substantial interobserver agreement.

3D MR angiography with ramp-shaped flip-angle distribution

This study addressed the use of 3D MR angiography with flip angles (FAs) linearly varying across the excitation volume in order to diminish spin saturation. The shape of the ramp profile was varied to optimize the method for different regions and pathological alterations. Radio frequency pulses with ramp-shaped excitation profiles were generated using Fourier transformation and integrated into a flow-compensated 3D-FISP sequence. With the use of ramp-shaped excitation profiles good results were obtained for intracranial arteries as well as for neck arteries (i.e. carotid and vertebral arteries) which were demonstrated in 6 healthy volunteers and in 5 patients with various stenoses and anomalies of the carotid and vertebral arteries. With this technique it was possible to use increased thicknesses of the excitation volume (slab) up to 256 mm. Ramp-shaped excitation pulses with linearly increasing FAs in main flow direction can provide improved contrast of the vessel parts located distally to the entry side of the slab. Although this method has no advantage concerning complex flow or other dephasing effects; its particular effectiveness lies in the reduction of spin saturation.

Giant cell tumor of the occipital bone in a case of von Recklinghausen neurofibromatosis

Von Recklinghausen neurofibromatosis (NF1) is the most common hereditary syndrome predisposing to neoplasia. The most common symptomatic manifestation of NF1 is the plexiform neurofibroma. We describe the case of a patient with classical von Recklinghausen neurofibromatosis presenting with a giant cell tumor (GCT) of the occipital bone infiltrating a surrounding plexiform neurofibroma.

Mouse T cell membrane proteins Rt6-1 and Rt6-2 are arginine/protein mono(ADPribosyl)transferases and share secondary structure motifs with ADP-ribosylating bacterial toxins

Mono ADP-ribosylation is a posttranslational protein modification that has been implicated in the regulation of key biological functions in bacteria as well as in animals. Recently, the first cDNAs for eucaryotic mono(ADPribosyl)transferases were cloned and found to exhibit significant sequence similarity only to one other known protein, the T cell differentiation antigen Rt6. In this paper we describe secondary structure analyses of Rt6 and related proteins and show conserved structure motifs and amino acid residues consistent with a common ancestry of these eucaryotic proteins and bacterial ADP-ribosyltransferases. Moreover, we have expressed soluble mouse Rt6-1 and Rt6-2 gene products in which C-terminal tags (FLAG-His6) replace the native glycosylphosphatidylinositol anchor signal sequences. Purified recombinant Rt6-2, but not Rt6-1, shows NAD+ glycohydrolase activity, which is inhibited by the arginine analogue agmatine. Immunoprecipitation of recombinant Rt6-1 and Rt6-2 with anti-FLAG M2 antibody followed by incubation with [32P]NAD+ leads to rapid and covalent incorporation of radioactivity into the light chain of the M2 antibody. The bound label is resistant to treatment with HgCl2 but sensitive to NH2OH, characteristic of arginine-linked ADP-ribosylation. These results demonstrate that Rt6-1 and RT6-2 possess the enzymatic activities typical for NAD+-dependent arginine/protein mono(ADPribosyl)transferases (EC 2.4.2.31). They are the first such enzymes to be molecularly characterized in the immune system.

Fixation instability and oculomotor abnormalities in Friedreich's ataxia

Eye movements were studied in 13 patients with Friedreich's ataxia and correlated with MRI findings to investigate whether oculomotor abnormalities can be traced to cerebellar disturbances in this disease. One of the most prominent eye signs was fixation instability (square-wave jerks, SWJ.). Besides SWJ the patients showed various combinations of cerebellar, vestibular and brain-stem oculomotor signs. Our patients did not comprise a homogeneous group with regard to their oculomotor findings. There was no correlation between the severity of any of the so-called cerebellar oculomotor disturbances and the number of SWJ. We tried to correlate the extent of oculomotor disturbances with floccular atrophy and atrophy of the dorsal vermis on MRI in seven of the patients. None of the oculomotor features (including SWJ) correlated with flocculus or dorsal vermis size. Furthermore, floccular and vermal measurements on MRI were normal. Accordingly, we think it unlikely that the oculomotor disturbances, including SWJ, are attributable to cerebellar pathology per se.

Scotoma perception in white-noise-field campimetry and postchiasmal visual pathway lesions

The authors examined 59 patients (32 women and 27 men) suffering from homonymous hemianopia by white-noise-field campimetry (Tübingen Electronic Campimeter) and by conventional perimetry (Tübingen Automatic Perimeter or Tübingen Manual Perimeter) and by computerized tomography (CT) or magnetic resonance imaging (MR). In all, 56 patients showed neuroradiologically detectable cerebral lesions, which were superimposed in a reconstructed "reference brain". Of these 56 patients, 18 were not capable of perceiving any white-noise-field scotoma, although their conventional perimetric findings showed defects. Lesions of these patients were concentrated along the optic radiation and spared the primary visual cortex. The lesions of the remaining 38 patients with scotoma detectable in both methods were accumulated in area V1, the primary visual cortex. The lesions of 6 patients, who had had persistent scotoma perception for more than 2 years, were situated at the occipital pole. The lesions of 8 patients with vanishing scotoma were concentrated in more rostral areas.

[Factitious disease caused by secret administration of the oral anticoagulant phenprocoumon: study of 16 personal cases]

BACKGROUND

It is frequently difficult to disclose covert ingestion of cumarins being the underlying cause of a bleeding disorder.

PATIENTS AND METHODS

We report on 16 cases (15 patients) of phenprocoumon (Marcumar) abuse. All patients (9 females, 6 males) were admitted to the hospital because of bleeding and/or prolonged thromboplastin times. Analysis of phenprocoumon in the blood was performed by HPLC.

RESULTS AND CONCLUSIONS

The clinical presentation of the bleeding was highly variable. Thromboplastin times ranged from < 5 to 58%. With the exception of two patients with hepatic dysfunctions factor V activity was normal. All but one patient denied the ingestion of Marcumar. One patient died from hemorrhage. Two types of patients emerge from our series: Type I is the young nurse (8 cases), type II the usually male patient formerly treated with phenprocoumon (5 cases). Type I patients had long medical histories and showed autoaggressive behavior including the artificial manipulation of disorders other than hemorrhage. Thromboplastin times however were within or close to the therapeutic range (10 to 25%). Type II patients did not simulate other diseases in addition to hemorrhage. Thromboplastin times were longer than in type I patients. In all instances discrimination between non suicidal and suicidal behaviour was difficult. Psychiatric consultance is indicated.

Bilateral spastic cerebral palsy--MRI pathology and origin. Analysis from a representative series of 56 cases

MRI of the brain was performed on 56 children with bilateral spastic cerebral palsy (CP) at a mean age of 10.7 years. Specific pathology was found in 91 per cent; periventricular leukomalacia was present in 42 per cent of term- and 87 per cent of preterm-born children. Parasagittal subcorticocortical injury, multicystic encephalomalacia and basal ganglia lesions were identified in 16 per cent, in all but one associated with severe peri-/neonatal events at term or near term. Maldevelopment comprised 9 per cent, all but one found in term-born children. MRI morphology correlated strikingly with outcome. Periventricular leukomalacia was associated with more severe disability in term- than preterm-born children.

Tracking of cerebral vessels in MR angiography after highpass filtering

Maximum intensity projection (MIP), the commonly used technique for calculating MR-angiograms from three-dimensional (3D) datasets, often fails to visualize small vessels due to superposition of background signal. An improved vascular depiction can be reached by application of a connectivity algorithm, but a very good delimitation of vessel signals from signals of stationary tissue is required for this technique. Results of intracranial vessel tracking could be improved by a 3D interpolation and a preceding highpass filtering of the 3D image dataset.

Multiple system atrophy: natural history, MRI morphology, and dopamine receptor imaging with 123IBZM-SPECT

Sixteen patients with a clinical diagnosis of probable multiple system atrophy (MSA) were examined clinically by MRI and by 123I-iodobenzamide single photon emission computed tomography (IBZM-SPECT). The clinical records of another 16 patients were also analysed retrospectively. On the basis of their clinical presentation, patients were subdivided into those with prominent parkinsonism (MSA-P, n = 11) and those with prominent cerebellar ataxia (MSA-C, n = 21). Autonomic symptoms were present in all patients and preceded the onset of motor symptoms in 63% of patients. Calculated median lifetime and the median time to become wheelchair bound after onset of disease were significantly shorter for MSA-P than for MSA-C (lifetime: 4.0 v 9.1 years; wheelchair: 3.1 vs 5.0 years) suggesting a better prognosis for cerebellar patients. A significant loss of striatal dopamine receptors (below 2 SD threshold) was detected by IBZM-SPECT in 63% of the patients (56% below 2.5 SD threshold). There was no difference between patients with MSA-C and those with MSA-P in the proportion with significant receptor loss and the extent of dopamine receptor loss. Planimetric MRI evaluation showed cerebellar and brainstem atrophy in both groups. Atrophy was more pronounced in patients with MSA-C than in those with MSA-P. Pontocerebellar hyperintensities and putaminal hypointensities on T2 weighted MRI were found in both groups. Pontocerebellar signal abnormalities were more pronounced in MSA-C than in MSA-P, whereas the rating scores for area but not for intensity of putaminal abnormalities were higher in MSA-P. MRI and IBZM-SPECT provide in vivo evidence for combined basal ganglia and pontocerebellar involvement in almost all patients in this series.

The "dural tail" adjacent to meningiomas studied by dynamic contrast-enhanced MRI: a comparison with histopathology

We examined 32 patients with intracranial tumors (17 meningiomas, 8 neuromas, 7 pituitary adenomas) by conventional and dynamic contrast-enhanced MRI. Our aim was to clarify whether the pathological dural contrast enhancement adjacent to meningiomas (the "dural tail") is specific to meningiomas and, more important, whether it represents neoplastic dural infiltration or hypervascularization as a tumor accompanying reaction. A "dural tail" was found in 9 of 17 meningiomas. None of the other extra-axial tumours (neuromas, pituitary adenomas) showed comparable dural enhancement. Dynamic examinations with an ultrafast single slice imaging technique (snapshot-FLASH) after a bolus injection of contrast medium showed a "dural tail" in seven out of these nine meningiomas, while in two cases the "dural tail" turned out to be a cortical vein with a characteristic dynamic contrast enhancement pattern. In the dynamic study all seven "dural tails" were found to have earlier, steeper contrast enhancement than the corresponding tumours. All the tumours and part of the adjacent dura mater in four of the seven meningiomas with dural enhancement were examined histopathologically. In none of these four cases was neoplastic tissue found more than 2 mm away from the main tumour. The results strongly support the suggestion that the "dural tail" adjacent to meningiomas represents a hypervascular, non-neoplastic dural reaction.

The effects of linearly increasing flip angles on 3D inflow MR angiography

As recently demonstrated, spin saturation effects in 3D time-of-flight (TOF) MR angiography (MRA) can be reduced by using RF pulses with linearly increasing flip angles (ramp pulses) in the main direction of flow. We developed a model for calculating the signal distribution of proton flow within the excitation volume (slab) for different ramp slopes and compared the results with the measured distribution for the lower-leg arteries. The ramp pulses were generated using the Fourier transformation of the desired excitation profiles. With a bandwidth of 6 kHz and a pulse length of 2.56 ms satisfactory ramps with variable slopes were generated and applied in a standard flow-compensated 3D FISP sequence. The effects on the signal distribution in the resulting angiograms of the lower limbs revealed a considerable reduction of saturation losses in agreement with the calculations. Calculated optimal ramp slopes are provided for flow velocities ranging from 5 to 50 cm/s and excitation volumes ranging from 5 to 25 cm.

Individualization of 5-fluorocytosine therapy

Using a convenient and fast HPLC procedure we determined serum concentrations of the fungistatic agent 5-fluorocytosine (5-FC) in 375 samples from 60 patients treated with this drug. The mean trough concentration (n = 127) was 64.3 mg/l (range: 11.8-208.0 mg/l), the mean peak concentration (n = 122) was 99.9 mg/l (range: 25.6-263.8 mg/l), the mean nonpeak/nontrough concentration (n = 126) was 80.1 mg/l (range: 10.5-268.0 mg/l). Totally 134 (35.7%) samples were outside the therapeutic range (25-100 mg/l), 108 (28.8%) being too high, 26 (6.9%) being too low. Forty-four (73%) patients showed 5-FC serum concentrations outside the therapeutic range at least once during the treatment course. In a prospective study we performed 65 dosage predictions on 30 patients by use of a 3-point method previously developed for aminoglycoside dosage adaptation. The mean absolute prediction error of the dosage adaptation was +0.7 mg/l (range: -26.0 to +28.0 mg/l). The root mean square prediction error was 10.7 mg/l. The mean predicted concentration (65.3 mg/l) agreed very well with the mean measured concentration (64.6 mg/l). The frequency distribution of 5-FC serum concentrations indicates that 5-FC monitoring is important. The applied pharmacokinetic method allows individual adaptations of 5-FC dosage with a clinically acceptable prediction error.

Hemodynamics in subclavian-steal syndrome: difficulties in their evaluation

In a patient with subclavian-steal syndrome transcranial Doppler sonography detected transient retrograde basilar blood flow whereas routine angiography failed to document this condition. Thus, orthograde basilar blood flow at routine angiography does not rule out basilar steal. Presumably the forced injection of contrast media conceals less pronounced steal phenomena. Our exemplary case indicates that a subgroup of patients with vertebro-basilar symptoms concomitant with basilar flow abnormalities may benefit from invasive or semi-invasive treatment.