Doppler ultrasonography of peripheral vascular disease: the potential for ultrasound contrast agents

Noninvasive diagnosis of peripheral vascular disease started with the introduction of Doppler technology. The development of high frequency ultrasound and color Doppler imaging allows continuous assessment of vascular disorders along the arterial tree. However, the technique remains operator dependent. It also suffers from anatomic limitations, such as bowel gas and ultrasound attenuation due to depth or wall calcification. Ultrasound contrast agents increase the Doppler signal intensity and should therefore reduce the rate of technical failures. They are useful for detecting the flux in cases of attenuated ultrasound beam and reduced blood flow. Their administration using continuous infusion protocols increases the duration of the effect. New imaging modalities such as harmonic imaging and pulse inversion imaging reduce Doppler artifacts and allow real time detection of the microbubbles flowing in the blood stream. Future directions include ultrasound-guided therapy of occlusion using encapsulated drugs targeted to the thrombus.

Genetic restriction of murine hepatitis virus type 3 expression in liver and brain: comparative study in BALB/c and C3H mice by immunochemistry and hybridization in situ

To study the host-dependent genetic variations in murine hepatitis virus type 3 (MHV 3) induced diseases, we localized the sites of MHV 3 (Mill Hill strain) expression within liver and brain by immunohistochemistry or hybridization in situ. Two strains of mice were studied: BALB/c mice, which develop an acute and lethal hepatitis and C3H mice which develop a chronic brain infection. In BALB/c mice, viral RNA and antigens appeared during the first 24h post infection (p.i.) in liver, whereas viral RNA was barely detectable in brain, up until death at day 3 p.i. In C3H mice, viral RNA and antigens were detected simultaneously in liver and brain only at day 2 p.i. In brain, the virus was detected in meningeal and ependymal cells and in perivascular cortical areas (days 5 and 7 p.i.). After day 49, the virus was no longer detected in brain parenchyma, but persisted in meningeal cells. Two host-dependent genetic differences in viral processing were observed in the liver: (1) the virus was first detected in Kupffer cells in BALB/c mice and mostly in hepatocytes in C3H mice; (2) in BALB/c mice, the 180 kDa S viral glycoprotein appeared more frequently cleaved in 90 kDa form than in C3H mice.

Human immunodeficiency virus type 1-infected monocytic cells can destroy human neural cells after cell-to-cell adhesion

Primary cultures of human embryonic neurons and astrocytes have been used to test the interactions between neural cells and either human immunodeficiency virus type 1 (HIV-1) or HIV-1-infected monocytes. After direct infection with HIV-1, neither morphological alteration of neurons and astrocytes nor signs of viral replication were observed. Similarly, cultured human neurons and astrocytes were resistant to incubation with the supernatant of HIV-1-infected U937 cells, a human monoblastoid cell line. In contrast, HIV-1-infected U937 monocytic cells adhered to neural cells and induced large plaques of necrosis surrounding them. This cytopathic effect began at the time of viral replication (day 16 after infection). Its intensity depended on that of viral replication, and its range was identical to the region of diffusion of viral antigens, as judged by immunocytochemistry. The cytopathic effect was not dependent on the release of free radicals. It could not be induced by cytokines or cytokine-stimulated U937 cells. It is likely that this cytopathic effect depends on the release of viral antigens either within the site of adherence itself or within close range of the astrocyte membrane.

[Encephalitis with viral replication. Clinical aspects, prognosis and treatment]

Encephalites with viral replication are due to multiplication of a virus within the central nervous system. Diagnosis and initial therapeutic decisions rest on simple clinical and paraclinical findings: age of the child, presence of high-grade fever, presence and localization of seizures, CSF characteristics, and EEG findings. Acyclovir is always indicated in a drowsy child with a high fever who has even a brief seizure and CSF abnormalities.

[Acute hydrocephalus due to Candida meningitis in a 2-month-old infant]

A case of triventricular acute hydrocephalus is reported in a 2 month-old male. The etiology was a Candida sepsis with neonatal onset and subacute course of meningitis and arthritis. No immune deficiency was detected and antibiotic treatment appeared to be the only predisposing factor to systemic candidiasis in this neonate. The condition was treated successfully with amphotericin B, fluocytosin and ketoconazole. At follow up, 17 months later, the development of the child appeared normal.

Effect of cyclosporin A on an experimental chronic viral infection of the central nervous system

The effects of cyclosporin A (CsA) on neuropathological lesions induced by a chronic viral infection have been tested in the experimental model of the mouse hepatitis virus 3 (MHV3) infection. Daily injections of CsA (50 mg/kg) inhibited the expression of the MHV3-induced ependymitis, meningitis, hydrocephalus and vasculitis. The effect was preserved even if CsA treatment was initiated 15 days after virus infection but was lost if CsA treatment was given later on or for a shorter period of time. Viral titers in brains of chronically infected mice were not affected by CsA treatment. During the first week following MHV3 infection, CsA treatment increased both the percentage of acute death (31 vs. 10%) and the viral titers in brain and liver of infected mice. In this model, the timing of CsA treatment appeared critical for the balance between its beneficial effect on CNS lesions and the risk of increased acute mortality.

Selective tropism of a neurotropic coronavirus for ependymal cells, neurons, and meningeal cells

The ability of a neurotropic virus, mouse hepatitis virus type 3 (MHV3), to invade the central nervous system (CNS) and to recognize cells selectively within the brain was investigated in vivo and in vitro. In vivo, MHV3 induced in C3H mice a genetically controlled infection of meningeal cells, ependymal cells, and neurons. In vitro, purified MHV3 bound to the surface of isolated ependymal cells and cultured cortical neurons but not to oligodendrocytes or cultured astrocytes. MHV3 replicated within cultured cortical neurons and neuroblastoma cells (NIE 115); infected cultured neurons nonetheless survived and matured normally for a 7-day period postinfection. On the other hand, MHV3 had a low affinity for cortical glial cells or glioma cells (C6 line), both of which appear to be morphologically unaltered by viral infection. Finally, MHV3 infected and disrupted cultured meningeal cells. This suggests that differences in the affinity of cells for MHV3 are determinants of the selective vulnerability of cellular subpopulations within the CNS. In vivo, a higher titer of virus was needed for CNS penetration in the genetically resistant (A/Jx) mice than in the susceptible (C57/BL6) mouse strain. However, in spite of viral invasion, no neuropathological lesions developed. In vitro viral binding to adult ependymal cells of susceptible and resistant strains of mice was identical. Genetic resistance to MHV3-CNS infection appeared to be mediated both by a peripheral mechanism limiting viral penetration into the CNS and by intra-CNS mechanisms, presumably at a stage after viral attachment to target cells.

Neurotransmitter changes during development of cortical neuronal cultures

Benzodiazepine (BDZ) ligands clonazepam (CLO) and Ro5-4864 which preferentially bind to neuronal and non-neuronal elements, respectively, have been used to follow neuronal and non-neuronal development in fetal murine cortical cultures. CLO-displaceable BDZ binding, choline acetyltransferase (CAT) activity, high-affinity delta-aminobutyric acid (GABA) uptake, and glutamic acid decarboxylase (GAD) activity reached a maximum value at the end of the second week in culture reflecting maximum neuronal maturation and development. There is a developmental order of these four functions: CAT activity (main enzyme in the synthesis of acetylcholine, a stimulating neurotransmitter) reached maximal levels first, 3H-GABA uptake and CLO-displaceable flunitrazepam receptor binding reached maximal levels 1 day later, and 4 days later GAD activity (primary enzyme in the synthesis of GABA, an inhibitor neurotransmitter) reached maximal levels.

[Malignant phenylketonuria caused by biopterin synthetase deficiency. Study of neuromediator catabolites in the cerebrospinal fluid during treatment]

In a child presenting with malignant phenylketonuria due to dihydrobiopterin synthetase deficiency, the authors studied the cerebrospinal fluid (CSF) homovanillic acid and 5 hydroxyindole acetic acid levels under different circumstances: without treatment; under a treatment with tetrahydrobiopterin used alone at various doses; under a treatment associating BH4, L-dopa, 5 hydroxytryptophan and carbidopa, with increasing doses and varying administration schedules. This biological study compared with clinical evolution, shows clearly the inefficacy, regardless of the doses, of BH4 on the CSF levels of neuromediators and on the neurological status, and the excellent efficacy of neuromediator precursors provided high doses are given, divided in the nyctohemeral period.

[Monoarthritis with positive Yersinia pseudotuberculosis serology in an 18-month-old girl]

A case of Yersinia pseudo-tuberculosis arthritis is reported in a 18 month-old girl. The authors emphasize the rarity of such cases, the value of testing for Yersinia antibodies in cases with arthritis of unknown origin and the uncertain long-term outcome.

[Thyroid involvement in histiocytosis X]

A thyroid involvement is reported in a 10 year-old boy with histiocytosis X. It was revealed by goiter and hypothyroidism following diabetes insipidus and growth hormone deficiency. Hypothyroidism was exclusively due to the invasion of thyroid by the tumor, while the other endocrine changes were in favor of the histiocytic infiltration of hypothalamus. The exceptional feature of thyroid involvement in disseminated histiocytosis X is emphasized.

Carotid artery surgery in patients over 70 years of age

Between 1965 and 1979, 934 patients underwent 1,057 operations for extracranial carotid stenosis at this institute, and over a recent 30-month period 463 patients underwent 511 operations of this type. This number is equal to the total of operations performed during the years 1965-1976. The increase in the frequency of carotid artery surgery has been more marked in patients of over 70 years. The percentage of elderly patients has increased from 17.5% to 27% in the recent period. In the latter group of 511 operations, results were good in 93.17% of cases, while there was a mortality rate of 1.95% (1% of which were directly related to the surgery), in 1.95% the neurologic condition deteriorated and in 3.13% there was no change. In the first period the mortality rate for patients over 70 years of age was 7.69%. In the second it was 3.27% (1.63% of which were due to non-neurologic causes), 4.09% deteriorated, in 2.18% there was no change and good results were obtained in 90.46%.

[The Doppler test: its practical importance in the study of lesions of the supra-aortic trunks]

Ultrasonography by the Doppler effect is of indisputable use in the investigation of lesions of the supra-aortic trunks leading to the brain. It allows a direct study of the extracranial carotidian and vertebral axes, and gives an idea of the intracerebral circulation. It detects the main lesions affecting them, provided that such lesions have hemodynamic repercussions. The Doppler does not replace arteriography, but is a complementary exam making it possible to decide on or to dismiss the need for it. Its harmlessness and simplicity make it a standard exam in cerebral vascular pathology.